multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{AllLanguageSettings, LanguageSettings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use settings::Settings;
  34use smallvec::SmallVec;
  35use smol::future::yield_now;
  36use std::{
  37    any::type_name,
  38    borrow::Cow,
  39    cell::{Cell, OnceCell, Ref, RefCell},
  40    cmp, fmt,
  41    future::Future,
  42    io,
  43    iter::{self, FromIterator},
  44    mem,
  45    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  46    rc::Rc,
  47    str,
  48    sync::{Arc, OnceLock},
  49    time::Duration,
  50};
  51use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  52use text::{
  53    BufferId, Edit, LineIndent, TextSummary,
  54    locator::Locator,
  55    subscription::{Subscription, Topic},
  56};
  57use theme::SyntaxTheme;
  58use unicode_segmentation::UnicodeSegmentation;
  59use util::post_inc;
  60use ztracing::instrument;
  61
  62pub use self::path_key::{PathExcerptInsertResult, PathKey};
  63
  64pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  65
  66pub fn excerpt_context_lines(cx: &App) -> u32 {
  67    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  68}
  69
  70#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  71pub struct ExcerptId(u32);
  72
  73/// One or more [`Buffers`](Buffer) being edited in a single view.
  74///
  75/// See <https://zed.dev/features#multi-buffers>
  76pub struct MultiBuffer {
  77    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  78    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  79    snapshot: RefCell<MultiBufferSnapshot>,
  80    /// Contains the state of the buffers being edited
  81    buffers: BTreeMap<BufferId, BufferState>,
  82    /// Mapping from path keys to their excerpts.
  83    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  84    /// Mapping from excerpt IDs to their path key.
  85    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  86    /// Mapping from buffer IDs to their diff states
  87    diffs: HashMap<BufferId, DiffState>,
  88    subscriptions: Topic<MultiBufferOffset>,
  89    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  90    singleton: bool,
  91    /// The history of the multi-buffer.
  92    history: History,
  93    /// The explicit title of the multi-buffer.
  94    /// If `None`, it will be derived from the underlying path or content.
  95    title: Option<String>,
  96    /// The writing capability of the multi-buffer.
  97    capability: Capability,
  98    buffer_changed_since_sync: Rc<Cell<bool>>,
  99}
 100
 101#[derive(Clone, Debug, PartialEq, Eq)]
 102pub enum Event {
 103    ExcerptsAdded {
 104        buffer: Entity<Buffer>,
 105        predecessor: ExcerptId,
 106        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 107    },
 108    ExcerptsRemoved {
 109        ids: Vec<ExcerptId>,
 110        /// Contains only buffer IDs for which all excerpts have been removed.
 111        /// Buffers that still have remaining excerpts are never included.
 112        removed_buffer_ids: Vec<BufferId>,
 113    },
 114    ExcerptsExpanded {
 115        ids: Vec<ExcerptId>,
 116    },
 117    ExcerptsEdited {
 118        excerpt_ids: Vec<ExcerptId>,
 119        buffer_ids: Vec<BufferId>,
 120    },
 121    DiffHunksToggled,
 122    Edited {
 123        edited_buffer: Option<Entity<Buffer>>,
 124        is_local: bool,
 125    },
 126    TransactionUndone {
 127        transaction_id: TransactionId,
 128    },
 129    Reloaded,
 130    LanguageChanged(BufferId, bool),
 131    Reparsed(BufferId),
 132    Saved,
 133    FileHandleChanged,
 134    DirtyChanged,
 135    DiagnosticsUpdated,
 136    BufferDiffChanged,
 137}
 138
 139/// A diff hunk, representing a range of consequent lines in a multibuffer.
 140#[derive(Debug, Clone, PartialEq, Eq)]
 141pub struct MultiBufferDiffHunk {
 142    /// The row range in the multibuffer where this diff hunk appears.
 143    pub row_range: Range<MultiBufferRow>,
 144    /// The buffer ID that this hunk belongs to.
 145    pub buffer_id: BufferId,
 146    /// The range of the underlying buffer that this hunk corresponds to.
 147    pub buffer_range: Range<text::Anchor>,
 148    /// The excerpt that contains the diff hunk.
 149    pub excerpt_id: ExcerptId,
 150    /// The range within the buffer's diff base that this hunk corresponds to.
 151    pub diff_base_byte_range: Range<BufferOffset>,
 152    /// The status of this hunk (added/modified/deleted and secondary status).
 153    pub status: DiffHunkStatus,
 154    /// The word diffs for this hunk.
 155    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 156}
 157
 158impl MultiBufferDiffHunk {
 159    pub fn status(&self) -> DiffHunkStatus {
 160        self.status
 161    }
 162
 163    pub fn is_created_file(&self) -> bool {
 164        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 165            && self.buffer_range.start.is_min()
 166            && self.buffer_range.end.is_max()
 167    }
 168
 169    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 170        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 171        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 172        start..end
 173    }
 174}
 175
 176pub type MultiBufferPoint = Point;
 177type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 178type ExcerptPoint = ExcerptDimension<Point>;
 179
 180#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 181#[serde(transparent)]
 182pub struct MultiBufferRow(pub u32);
 183
 184impl MultiBufferRow {
 185    pub const MIN: Self = Self(0);
 186    pub const MAX: Self = Self(u32::MAX);
 187}
 188
 189impl ops::Add<usize> for MultiBufferRow {
 190    type Output = Self;
 191
 192    fn add(self, rhs: usize) -> Self::Output {
 193        MultiBufferRow(self.0 + rhs as u32)
 194    }
 195}
 196
 197pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 198    type TextDimension: TextDimension;
 199    fn from_summary(summary: &MBTextSummary) -> Self;
 200
 201    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 202
 203    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 204}
 205
 206// todo(lw): MultiBufferPoint
 207impl MultiBufferDimension for Point {
 208    type TextDimension = Point;
 209    fn from_summary(summary: &MBTextSummary) -> Self {
 210        summary.lines
 211    }
 212
 213    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 214        *self += *other;
 215    }
 216
 217    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 218        *self += summary.lines;
 219    }
 220}
 221
 222// todo(lw): MultiBufferPointUtf16
 223impl MultiBufferDimension for PointUtf16 {
 224    type TextDimension = PointUtf16;
 225    fn from_summary(summary: &MBTextSummary) -> Self {
 226        summary.lines_utf16()
 227    }
 228
 229    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 230        *self += *other;
 231    }
 232
 233    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 234        *self += summary.lines_utf16();
 235    }
 236}
 237
 238#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 239pub struct MultiBufferOffset(pub usize);
 240
 241impl fmt::Display for MultiBufferOffset {
 242    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 243        write!(f, "{}", self.0)
 244    }
 245}
 246
 247impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 248    type Sampler = MultiBufferOffsetUniformSampler;
 249}
 250
 251pub struct MultiBufferOffsetUniformSampler {
 252    sampler: rand::distr::uniform::UniformUsize,
 253}
 254
 255impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 256    type X = MultiBufferOffset;
 257
 258    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 259    where
 260        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 261        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 262    {
 263        let low = *low_b.borrow();
 264        let high = *high_b.borrow();
 265        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 266        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 267    }
 268
 269    #[inline] // if the range is constant, this helps LLVM to do the
 270    // calculations at compile-time.
 271    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 272    where
 273        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 274        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 275    {
 276        let low = *low_b.borrow();
 277        let high = *high_b.borrow();
 278        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 279        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 280    }
 281
 282    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 283        MultiBufferOffset(self.sampler.sample(rng))
 284    }
 285}
 286impl MultiBufferDimension for MultiBufferOffset {
 287    type TextDimension = usize;
 288    fn from_summary(summary: &MBTextSummary) -> Self {
 289        summary.len
 290    }
 291
 292    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 293        self.0 += *other;
 294    }
 295
 296    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 297        *self += summary.len;
 298    }
 299}
 300impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 301    type TextDimension = OffsetUtf16;
 302    fn from_summary(summary: &MBTextSummary) -> Self {
 303        MultiBufferOffsetUtf16(summary.len_utf16)
 304    }
 305
 306    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 307        self.0 += *other;
 308    }
 309
 310    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 311        self.0 += summary.len_utf16;
 312    }
 313}
 314
 315#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 316pub struct BufferOffset(pub usize);
 317
 318impl TextDimension for BufferOffset {
 319    fn from_text_summary(summary: &TextSummary) -> Self {
 320        BufferOffset(usize::from_text_summary(summary))
 321    }
 322    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 323        BufferOffset(usize::from_chunk(chunk))
 324    }
 325    fn add_assign(&mut self, other: &Self) {
 326        TextDimension::add_assign(&mut self.0, &other.0);
 327    }
 328}
 329impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 330    fn zero(cx: ()) -> Self {
 331        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 332    }
 333
 334    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 335        usize::add_summary(&mut self.0, summary, cx);
 336    }
 337}
 338
 339impl Sub for BufferOffset {
 340    type Output = usize;
 341
 342    fn sub(self, other: BufferOffset) -> Self::Output {
 343        self.0 - other.0
 344    }
 345}
 346
 347impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 348    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 349        self.0 += other.key;
 350    }
 351}
 352
 353impl language::ToPoint for BufferOffset {
 354    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 355        self.0.to_point(snapshot)
 356    }
 357}
 358
 359impl language::ToPointUtf16 for BufferOffset {
 360    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 361        self.0.to_point_utf16(snapshot)
 362    }
 363}
 364
 365impl language::ToOffset for BufferOffset {
 366    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 367        self.0.to_offset(snapshot)
 368    }
 369}
 370
 371impl language::ToOffsetUtf16 for BufferOffset {
 372    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 373        self.0.to_offset_utf16(snapshot)
 374    }
 375}
 376
 377#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 378pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 379
 380impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 381    type Output = MultiBufferOffsetUtf16;
 382
 383    fn add(self, rhs: usize) -> Self::Output {
 384        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 385    }
 386}
 387
 388impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 389    type Output = Self;
 390
 391    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 392        MultiBufferOffsetUtf16(self.0 + rhs)
 393    }
 394}
 395
 396impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 397    fn add_assign(&mut self, rhs: OffsetUtf16) {
 398        self.0 += rhs;
 399    }
 400}
 401
 402impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 403    fn add_assign(&mut self, rhs: usize) {
 404        self.0.0 += rhs;
 405    }
 406}
 407
 408impl Sub for MultiBufferOffsetUtf16 {
 409    type Output = OffsetUtf16;
 410
 411    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 412        self.0 - other.0
 413    }
 414}
 415
 416impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 417    type Output = MultiBufferOffsetUtf16;
 418
 419    fn sub(self, other: OffsetUtf16) -> Self::Output {
 420        MultiBufferOffsetUtf16(self.0 - other)
 421    }
 422}
 423
 424#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 425pub struct BufferOffsetUtf16(pub OffsetUtf16);
 426
 427impl MultiBufferOffset {
 428    const ZERO: Self = Self(0);
 429    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 430        self.0.saturating_sub(other.0)
 431    }
 432    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 433        MultiBufferOffset(self.0.saturating_sub(other))
 434    }
 435}
 436
 437impl ops::Sub for MultiBufferOffset {
 438    type Output = usize;
 439
 440    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 441        self.0 - other.0
 442    }
 443}
 444
 445impl ops::Sub<usize> for MultiBufferOffset {
 446    type Output = Self;
 447
 448    fn sub(self, other: usize) -> Self::Output {
 449        MultiBufferOffset(self.0 - other)
 450    }
 451}
 452
 453impl ops::SubAssign<usize> for MultiBufferOffset {
 454    fn sub_assign(&mut self, other: usize) {
 455        self.0 -= other;
 456    }
 457}
 458
 459impl ops::Add<usize> for BufferOffset {
 460    type Output = Self;
 461
 462    fn add(self, rhs: usize) -> Self::Output {
 463        BufferOffset(self.0 + rhs)
 464    }
 465}
 466
 467impl ops::AddAssign<usize> for BufferOffset {
 468    fn add_assign(&mut self, other: usize) {
 469        self.0 += other;
 470    }
 471}
 472
 473impl ops::Add<usize> for MultiBufferOffset {
 474    type Output = Self;
 475
 476    fn add(self, rhs: usize) -> Self::Output {
 477        MultiBufferOffset(self.0 + rhs)
 478    }
 479}
 480
 481impl ops::AddAssign<usize> for MultiBufferOffset {
 482    fn add_assign(&mut self, other: usize) {
 483        self.0 += other;
 484    }
 485}
 486
 487impl ops::Add<isize> for MultiBufferOffset {
 488    type Output = Self;
 489
 490    fn add(self, rhs: isize) -> Self::Output {
 491        MultiBufferOffset((self.0 as isize + rhs) as usize)
 492    }
 493}
 494
 495impl ops::Add for MultiBufferOffset {
 496    type Output = Self;
 497
 498    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 499        MultiBufferOffset(self.0 + rhs.0)
 500    }
 501}
 502
 503impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 504    fn add_assign(&mut self, other: MultiBufferOffset) {
 505        self.0 += other.0;
 506    }
 507}
 508
 509pub trait ToOffset: 'static + fmt::Debug {
 510    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 511    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 512}
 513
 514pub trait ToPoint: 'static + fmt::Debug {
 515    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 516    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 517}
 518
 519struct BufferState {
 520    buffer: Entity<Buffer>,
 521    last_version: RefCell<clock::Global>,
 522    last_non_text_state_update_count: Cell<usize>,
 523    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 524    excerpts: Vec<Locator>,
 525    _subscriptions: [gpui::Subscription; 2],
 526}
 527
 528struct DiffState {
 529    diff: Entity<BufferDiff>,
 530    main_buffer: Option<Entity<language::Buffer>>,
 531    _subscription: gpui::Subscription,
 532}
 533
 534impl DiffState {
 535    fn snapshot(&self, buffer_id: BufferId, cx: &App) -> DiffStateSnapshot {
 536        DiffStateSnapshot {
 537            buffer_id,
 538            diff: self.diff.read(cx).snapshot(cx),
 539            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 540        }
 541    }
 542}
 543
 544#[derive(Clone)]
 545struct DiffStateSnapshot {
 546    buffer_id: BufferId,
 547    diff: BufferDiffSnapshot,
 548    main_buffer: Option<language::BufferSnapshot>,
 549}
 550
 551impl std::ops::Deref for DiffStateSnapshot {
 552    type Target = BufferDiffSnapshot;
 553
 554    fn deref(&self) -> &Self::Target {
 555        &self.diff
 556    }
 557}
 558
 559#[derive(Clone, Debug, Default)]
 560struct DiffStateSummary {
 561    max_buffer_id: Option<BufferId>,
 562    added_rows: u32,
 563    removed_rows: u32,
 564}
 565
 566impl sum_tree::ContextLessSummary for DiffStateSummary {
 567    fn zero() -> Self {
 568        Self::default()
 569    }
 570
 571    fn add_summary(&mut self, other: &Self) {
 572        self.max_buffer_id = std::cmp::max(self.max_buffer_id, other.max_buffer_id);
 573        self.added_rows += other.added_rows;
 574        self.removed_rows += other.removed_rows;
 575    }
 576}
 577
 578impl sum_tree::Item for DiffStateSnapshot {
 579    type Summary = DiffStateSummary;
 580
 581    fn summary(&self, _cx: ()) -> DiffStateSummary {
 582        let (added_rows, removed_rows) = self.diff.changed_row_counts();
 583        DiffStateSummary {
 584            max_buffer_id: Some(self.buffer_id),
 585            added_rows,
 586            removed_rows,
 587        }
 588    }
 589}
 590
 591impl sum_tree::KeyedItem for DiffStateSnapshot {
 592    type Key = Option<BufferId>;
 593
 594    fn key(&self) -> Option<BufferId> {
 595        Some(self.buffer_id)
 596    }
 597}
 598
 599impl<'a> Dimension<'a, DiffStateSummary> for Option<BufferId> {
 600    fn zero(_cx: ()) -> Self {
 601        None
 602    }
 603
 604    fn add_summary(&mut self, summary: &DiffStateSummary, _cx: ()) {
 605        *self = std::cmp::max(*self, summary.max_buffer_id);
 606    }
 607}
 608
 609fn find_diff_state(
 610    diffs: &SumTree<DiffStateSnapshot>,
 611    buffer_id: BufferId,
 612) -> Option<&DiffStateSnapshot> {
 613    let key = Some(buffer_id);
 614    let (.., item) = diffs.find::<Option<BufferId>, _>((), &key, Bias::Left);
 615    item.filter(|entry| entry.buffer_id == buffer_id)
 616}
 617
 618fn remove_diff_state(diffs: &mut SumTree<DiffStateSnapshot>, buffer_id: BufferId) {
 619    let key = Some(buffer_id);
 620    let mut cursor = diffs.cursor::<Option<BufferId>>(());
 621    let mut new_tree = cursor.slice(&key, Bias::Left);
 622    if key == cursor.end() {
 623        cursor.next();
 624    }
 625    new_tree.append(cursor.suffix(), ());
 626    drop(cursor);
 627    *diffs = new_tree;
 628}
 629
 630impl DiffState {
 631    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 632        DiffState {
 633            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 634                BufferDiffEvent::DiffChanged(DiffChanged {
 635                    changed_range,
 636                    base_text_changed_range: _,
 637                    extended_range,
 638                }) => {
 639                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 640                    let range = if use_extended {
 641                        extended_range.clone()
 642                    } else {
 643                        changed_range.clone()
 644                    };
 645                    if let Some(range) = range {
 646                        this.buffer_diff_changed(diff, range, cx)
 647                    }
 648                    cx.emit(Event::BufferDiffChanged);
 649                }
 650                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 651                _ => {}
 652            }),
 653            diff,
 654            main_buffer: None,
 655        }
 656    }
 657
 658    fn new_inverted(
 659        diff: Entity<BufferDiff>,
 660        main_buffer: Entity<language::Buffer>,
 661        cx: &mut Context<MultiBuffer>,
 662    ) -> Self {
 663        let weak_main_buffer = main_buffer.downgrade();
 664        DiffState {
 665            _subscription: cx.subscribe(&diff, {
 666                move |this, diff, event, cx| {
 667                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 668                        return;
 669                    };
 670                    match event {
 671                        BufferDiffEvent::DiffChanged(DiffChanged {
 672                            changed_range: _,
 673                            base_text_changed_range,
 674                            extended_range: _,
 675                        }) => {
 676                            if let Some(base_text_changed_range) = base_text_changed_range {
 677                                this.inverted_buffer_diff_changed(
 678                                    diff,
 679                                    main_buffer,
 680                                    base_text_changed_range.clone(),
 681                                    cx,
 682                                );
 683                            }
 684                            cx.emit(Event::BufferDiffChanged);
 685                        }
 686                        BufferDiffEvent::LanguageChanged => {
 687                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 688                        }
 689                        _ => {}
 690                    }
 691                }
 692            }),
 693            diff,
 694            main_buffer: Some(main_buffer),
 695        }
 696    }
 697}
 698
 699/// The contents of a [`MultiBuffer`] at a single point in time.
 700#[derive(Clone, Default)]
 701pub struct MultiBufferSnapshot {
 702    excerpts: SumTree<Excerpt>,
 703    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 704    diffs: SumTree<DiffStateSnapshot>,
 705    diff_transforms: SumTree<DiffTransform>,
 706    excerpt_ids: SumTree<ExcerptIdMapping>,
 707    replaced_excerpts: Arc<HashMap<ExcerptId, ExcerptId>>,
 708    non_text_state_update_count: usize,
 709    edit_count: usize,
 710    is_dirty: bool,
 711    has_deleted_file: bool,
 712    has_conflict: bool,
 713    has_inverted_diff: bool,
 714    singleton: bool,
 715    trailing_excerpt_update_count: usize,
 716    all_diff_hunks_expanded: bool,
 717    show_deleted_hunks: bool,
 718    use_extended_diff_range: bool,
 719    show_headers: bool,
 720}
 721
 722// follower: None
 723// - BufferContent(Some)
 724// - BufferContent(None)
 725// - DeletedHunk
 726//
 727// follower: Some
 728// - BufferContent(Some)
 729// - BufferContent(None)
 730
 731#[derive(Debug, Clone)]
 732enum DiffTransform {
 733    // RealText
 734    BufferContent {
 735        summary: MBTextSummary,
 736        // modified_hunk_info
 737        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 738    },
 739    // ExpandedHunkText
 740    DeletedHunk {
 741        summary: TextSummary,
 742        buffer_id: BufferId,
 743        hunk_info: DiffTransformHunkInfo,
 744        base_text_byte_range: Range<usize>,
 745        has_trailing_newline: bool,
 746    },
 747}
 748
 749#[derive(Clone, Copy, Debug)]
 750struct DiffTransformHunkInfo {
 751    excerpt_id: ExcerptId,
 752    hunk_start_anchor: text::Anchor,
 753    hunk_secondary_status: DiffHunkSecondaryStatus,
 754    is_logically_deleted: bool,
 755}
 756
 757impl Eq for DiffTransformHunkInfo {}
 758
 759impl PartialEq for DiffTransformHunkInfo {
 760    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 761        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 762    }
 763}
 764
 765impl std::hash::Hash for DiffTransformHunkInfo {
 766    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 767        self.excerpt_id.hash(state);
 768        self.hunk_start_anchor.hash(state);
 769    }
 770}
 771
 772#[derive(Clone)]
 773pub struct ExcerptInfo {
 774    pub id: ExcerptId,
 775    pub buffer: Arc<BufferSnapshot>,
 776    pub buffer_id: BufferId,
 777    pub range: ExcerptRange<text::Anchor>,
 778    pub end_row: MultiBufferRow,
 779}
 780
 781impl std::fmt::Debug for ExcerptInfo {
 782    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 783        f.debug_struct(type_name::<Self>())
 784            .field("id", &self.id)
 785            .field("buffer_id", &self.buffer_id)
 786            .field("path", &self.buffer.file().map(|f| f.path()))
 787            .field("range", &self.range)
 788            .finish()
 789    }
 790}
 791
 792/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 793#[derive(Debug)]
 794pub struct ExcerptBoundary {
 795    pub prev: Option<ExcerptInfo>,
 796    pub next: ExcerptInfo,
 797    /// The row in the `MultiBuffer` where the boundary is located
 798    pub row: MultiBufferRow,
 799}
 800
 801impl ExcerptBoundary {
 802    pub fn starts_new_buffer(&self) -> bool {
 803        match (self.prev.as_ref(), &self.next) {
 804            (None, _) => true,
 805            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 806        }
 807    }
 808}
 809
 810#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 811pub struct ExpandInfo {
 812    pub direction: ExpandExcerptDirection,
 813    pub excerpt_id: ExcerptId,
 814}
 815
 816#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 817pub struct RowInfo {
 818    pub buffer_id: Option<BufferId>,
 819    pub buffer_row: Option<u32>,
 820    pub multibuffer_row: Option<MultiBufferRow>,
 821    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 822    pub expand_info: Option<ExpandInfo>,
 823    pub wrapped_buffer_row: Option<u32>,
 824}
 825
 826/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 827#[derive(Clone)]
 828struct Excerpt {
 829    /// The unique identifier for this excerpt
 830    id: ExcerptId,
 831    /// The location of the excerpt in the [`MultiBuffer`]
 832    locator: Locator,
 833    /// The buffer being excerpted
 834    buffer_id: BufferId,
 835    /// A snapshot of the buffer being excerpted
 836    buffer: Arc<BufferSnapshot>,
 837    /// The range of the buffer to be shown in the excerpt
 838    range: ExcerptRange<text::Anchor>,
 839    /// The last row in the excerpted slice of the buffer
 840    max_buffer_row: BufferRow,
 841    /// A summary of the text in the excerpt
 842    text_summary: TextSummary,
 843    has_trailing_newline: bool,
 844}
 845
 846/// A public view into an `Excerpt` in a [`MultiBuffer`].
 847///
 848/// Contains methods for getting the [`Buffer`] of the excerpt,
 849/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 850#[derive(Clone)]
 851pub struct MultiBufferExcerpt<'a> {
 852    excerpt: &'a Excerpt,
 853    diff_transforms:
 854        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 855    /// The offset in the multibuffer considering diff transforms.
 856    offset: MultiBufferOffset,
 857    /// The offset in the multibuffer without diff transforms.
 858    excerpt_offset: ExcerptOffset,
 859    buffer_offset: BufferOffset,
 860}
 861
 862#[derive(Clone, Debug)]
 863struct ExcerptIdMapping {
 864    id: ExcerptId,
 865    locator: Locator,
 866}
 867
 868/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 869/// These ranges are relative to the buffer itself
 870#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 871pub struct ExcerptRange<T> {
 872    /// The full range of text to be shown in the excerpt.
 873    pub context: Range<T>,
 874    /// The primary range of text to be highlighted in the excerpt.
 875    /// In a multi-buffer search, this would be the text that matched the search
 876    pub primary: Range<T>,
 877}
 878
 879impl<T: Clone> ExcerptRange<T> {
 880    pub fn new(context: Range<T>) -> Self {
 881        Self {
 882            context: context.clone(),
 883            primary: context,
 884        }
 885    }
 886}
 887
 888#[derive(Clone, Debug, Default)]
 889pub struct ExcerptSummary {
 890    excerpt_id: ExcerptId,
 891    /// The location of the last [`Excerpt`] being summarized
 892    excerpt_locator: Locator,
 893    widest_line_number: u32,
 894    text: MBTextSummary,
 895    count: usize,
 896}
 897
 898#[derive(Debug, Clone)]
 899pub struct DiffTransformSummary {
 900    input: MBTextSummary,
 901    output: MBTextSummary,
 902}
 903
 904/// Summary of a string of text.
 905#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 906pub struct MBTextSummary {
 907    /// Length in bytes.
 908    pub len: MultiBufferOffset,
 909    /// Length in UTF-8.
 910    pub chars: usize,
 911    /// Length in UTF-16 code units
 912    pub len_utf16: OffsetUtf16,
 913    /// A point representing the number of lines and the length of the last line.
 914    ///
 915    /// In other words, it marks the point after the last byte in the text, (if
 916    /// EOF was a character, this would be its position).
 917    pub lines: Point,
 918    /// How many `char`s are in the first line
 919    pub first_line_chars: u32,
 920    /// How many `char`s are in the last line
 921    pub last_line_chars: u32,
 922    /// How many UTF-16 code units are in the last line
 923    pub last_line_len_utf16: u32,
 924    /// The row idx of the longest row
 925    pub longest_row: u32,
 926    /// How many `char`s are in the longest row
 927    pub longest_row_chars: u32,
 928}
 929
 930impl From<TextSummary> for MBTextSummary {
 931    fn from(summary: TextSummary) -> Self {
 932        MBTextSummary {
 933            len: MultiBufferOffset(summary.len),
 934            chars: summary.chars,
 935            len_utf16: summary.len_utf16,
 936            lines: summary.lines,
 937            first_line_chars: summary.first_line_chars,
 938            last_line_chars: summary.last_line_chars,
 939            last_line_len_utf16: summary.last_line_len_utf16,
 940            longest_row: summary.longest_row,
 941            longest_row_chars: summary.longest_row_chars,
 942        }
 943    }
 944}
 945
 946impl From<MBTextSummary> for TextSummary {
 947    fn from(summary: MBTextSummary) -> Self {
 948        TextSummary {
 949            len: summary.len.0,
 950            chars: summary.chars,
 951            len_utf16: summary.len_utf16,
 952            lines: summary.lines,
 953            first_line_chars: summary.first_line_chars,
 954            last_line_chars: summary.last_line_chars,
 955            last_line_len_utf16: summary.last_line_len_utf16,
 956            longest_row: summary.longest_row,
 957            longest_row_chars: summary.longest_row_chars,
 958        }
 959    }
 960}
 961
 962impl From<&str> for MBTextSummary {
 963    fn from(text: &str) -> Self {
 964        MBTextSummary::from(TextSummary::from(text))
 965    }
 966}
 967
 968impl MultiBufferDimension for MBTextSummary {
 969    type TextDimension = TextSummary;
 970
 971    fn from_summary(summary: &MBTextSummary) -> Self {
 972        *summary
 973    }
 974
 975    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 976        *self += *summary;
 977    }
 978
 979    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 980        *self += *summary;
 981    }
 982}
 983
 984impl AddAssign for MBTextSummary {
 985    fn add_assign(&mut self, other: MBTextSummary) {
 986        let joined_chars = self.last_line_chars + other.first_line_chars;
 987        if joined_chars > self.longest_row_chars {
 988            self.longest_row = self.lines.row;
 989            self.longest_row_chars = joined_chars;
 990        }
 991        if other.longest_row_chars > self.longest_row_chars {
 992            self.longest_row = self.lines.row + other.longest_row;
 993            self.longest_row_chars = other.longest_row_chars;
 994        }
 995
 996        if self.lines.row == 0 {
 997            self.first_line_chars += other.first_line_chars;
 998        }
 999
1000        if other.lines.row == 0 {
1001            self.last_line_chars += other.first_line_chars;
1002            self.last_line_len_utf16 += other.last_line_len_utf16;
1003        } else {
1004            self.last_line_chars = other.last_line_chars;
1005            self.last_line_len_utf16 = other.last_line_len_utf16;
1006        }
1007
1008        self.chars += other.chars;
1009        self.len += other.len;
1010        self.len_utf16 += other.len_utf16;
1011        self.lines += other.lines;
1012    }
1013}
1014
1015impl AddAssign<TextSummary> for MBTextSummary {
1016    fn add_assign(&mut self, other: TextSummary) {
1017        *self += MBTextSummary::from(other);
1018    }
1019}
1020
1021impl MBTextSummary {
1022    pub fn lines_utf16(&self) -> PointUtf16 {
1023        PointUtf16 {
1024            row: self.lines.row,
1025            column: self.last_line_len_utf16,
1026        }
1027    }
1028}
1029
1030impl<K, V> MultiBufferDimension for DimensionPair<K, V>
1031where
1032    K: MultiBufferDimension,
1033    V: MultiBufferDimension,
1034{
1035    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
1036
1037    fn from_summary(summary: &MBTextSummary) -> Self {
1038        Self {
1039            key: K::from_summary(summary),
1040            value: Some(V::from_summary(summary)),
1041        }
1042    }
1043
1044    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
1045        self.key.add_text_dim(&summary.key);
1046        if let Some(value) = &mut self.value {
1047            if let Some(other_value) = summary.value.as_ref() {
1048                value.add_text_dim(other_value);
1049            }
1050        }
1051    }
1052
1053    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
1054        self.key.add_mb_text_summary(summary);
1055        if let Some(value) = &mut self.value {
1056            value.add_mb_text_summary(summary);
1057        }
1058    }
1059}
1060
1061#[derive(Clone)]
1062pub struct MultiBufferRows<'a> {
1063    point: Point,
1064    is_empty: bool,
1065    is_singleton: bool,
1066    cursor: MultiBufferCursor<'a, Point, Point>,
1067}
1068
1069pub struct MultiBufferChunks<'a> {
1070    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
1071    diff_transforms:
1072        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
1073    diffs: &'a SumTree<DiffStateSnapshot>,
1074    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
1075    buffer_chunk: Option<Chunk<'a>>,
1076    range: Range<MultiBufferOffset>,
1077    excerpt_offset_range: Range<ExcerptOffset>,
1078    excerpt_chunks: Option<ExcerptChunks<'a>>,
1079    language_aware: bool,
1080}
1081
1082pub struct ReversedMultiBufferChunks<'a> {
1083    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1084    current_chunks: Option<rope::Chunks<'a>>,
1085    start: MultiBufferOffset,
1086    offset: MultiBufferOffset,
1087}
1088
1089pub struct MultiBufferBytes<'a> {
1090    range: Range<MultiBufferOffset>,
1091    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1092    excerpt_bytes: Option<text::Bytes<'a>>,
1093    has_trailing_newline: bool,
1094    chunk: &'a [u8],
1095}
1096
1097pub struct ReversedMultiBufferBytes<'a> {
1098    range: Range<MultiBufferOffset>,
1099    chunks: ReversedMultiBufferChunks<'a>,
1100    chunk: &'a [u8],
1101}
1102
1103#[derive(Clone)]
1104struct DiffTransforms<MBD> {
1105    output_dimension: OutputDimension<MBD>,
1106    excerpt_dimension: ExcerptDimension<MBD>,
1107}
1108
1109impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1110    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1111        Self {
1112            output_dimension: OutputDimension::zero(cx),
1113            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1114                cx,
1115            ),
1116        }
1117    }
1118
1119    fn add_summary(
1120        &mut self,
1121        summary: &'a DiffTransformSummary,
1122        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1123    ) {
1124        self.output_dimension.add_summary(summary, cx);
1125        self.excerpt_dimension.add_summary(summary, cx);
1126    }
1127}
1128
1129#[derive(Clone)]
1130struct MultiBufferCursor<'a, MBD, BD> {
1131    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1132    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1133    diffs: &'a SumTree<DiffStateSnapshot>,
1134    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1135}
1136
1137#[derive(Clone)]
1138struct MultiBufferRegion<'a, MBD, BD> {
1139    buffer: &'a BufferSnapshot,
1140    is_main_buffer: bool,
1141    diff_hunk_status: Option<DiffHunkStatus>,
1142    excerpt: &'a Excerpt,
1143    buffer_range: Range<BD>,
1144    range: Range<MBD>,
1145    has_trailing_newline: bool,
1146}
1147
1148struct ExcerptChunks<'a> {
1149    excerpt_id: ExcerptId,
1150    content_chunks: BufferChunks<'a>,
1151    has_footer: bool,
1152}
1153
1154#[derive(Debug)]
1155struct BufferEdit {
1156    range: Range<BufferOffset>,
1157    new_text: Arc<str>,
1158    is_insertion: bool,
1159    original_indent_column: Option<u32>,
1160    excerpt_id: ExcerptId,
1161}
1162
1163#[derive(Clone, Copy, Debug, PartialEq)]
1164enum DiffChangeKind {
1165    BufferEdited,
1166    DiffUpdated { base_changed: bool },
1167    ExpandOrCollapseHunks { expand: bool },
1168}
1169
1170#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1171pub enum ExpandExcerptDirection {
1172    Up,
1173    Down,
1174    UpAndDown,
1175}
1176
1177impl ExpandExcerptDirection {
1178    pub fn should_expand_up(&self) -> bool {
1179        match self {
1180            ExpandExcerptDirection::Up => true,
1181            ExpandExcerptDirection::Down => false,
1182            ExpandExcerptDirection::UpAndDown => true,
1183        }
1184    }
1185
1186    pub fn should_expand_down(&self) -> bool {
1187        match self {
1188            ExpandExcerptDirection::Up => false,
1189            ExpandExcerptDirection::Down => true,
1190            ExpandExcerptDirection::UpAndDown => true,
1191        }
1192    }
1193}
1194
1195#[derive(Clone, Debug, PartialEq)]
1196pub struct IndentGuide {
1197    pub buffer_id: BufferId,
1198    pub start_row: MultiBufferRow,
1199    pub end_row: MultiBufferRow,
1200    pub depth: u32,
1201    pub tab_size: u32,
1202    pub settings: IndentGuideSettings,
1203}
1204
1205impl IndentGuide {
1206    pub fn indent_level(&self) -> u32 {
1207        self.depth * self.tab_size
1208    }
1209}
1210
1211impl MultiBuffer {
1212    pub fn new(capability: Capability) -> Self {
1213        Self::new_(
1214            capability,
1215            MultiBufferSnapshot {
1216                show_headers: true,
1217                show_deleted_hunks: true,
1218                ..MultiBufferSnapshot::default()
1219            },
1220        )
1221    }
1222
1223    pub fn without_headers(capability: Capability) -> Self {
1224        Self::new_(
1225            capability,
1226            MultiBufferSnapshot {
1227                show_deleted_hunks: true,
1228                ..MultiBufferSnapshot::default()
1229            },
1230        )
1231    }
1232
1233    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1234        let mut this = Self::new_(
1235            buffer.read(cx).capability(),
1236            MultiBufferSnapshot {
1237                singleton: true,
1238                show_deleted_hunks: true,
1239                ..MultiBufferSnapshot::default()
1240            },
1241        );
1242        this.singleton = true;
1243        this.set_excerpts_for_path(
1244            PathKey::sorted(0),
1245            buffer.clone(),
1246            [Point::zero()..buffer.read(cx).max_point()],
1247            0,
1248            cx,
1249        );
1250        this
1251    }
1252
1253    #[inline]
1254    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1255        Self {
1256            snapshot: RefCell::new(snapshot),
1257            buffers: Default::default(),
1258            diffs: HashMap::default(),
1259            subscriptions: Topic::default(),
1260            singleton: false,
1261            capability,
1262            title: None,
1263            excerpts_by_path: Default::default(),
1264            paths_by_excerpt: Default::default(),
1265            buffer_changed_since_sync: Default::default(),
1266            history: History::default(),
1267        }
1268    }
1269
1270    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1271        let mut buffers = BTreeMap::default();
1272        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1273        for (buffer_id, buffer_state) in self.buffers.iter() {
1274            buffer_state.buffer.update(new_cx, |buffer, _| {
1275                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1276            });
1277            buffers.insert(
1278                *buffer_id,
1279                BufferState {
1280                    buffer: buffer_state.buffer.clone(),
1281                    last_version: buffer_state.last_version.clone(),
1282                    last_non_text_state_update_count: buffer_state
1283                        .last_non_text_state_update_count
1284                        .clone(),
1285                    excerpts: buffer_state.excerpts.clone(),
1286                    _subscriptions: [
1287                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1288                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1289                    ],
1290                },
1291            );
1292        }
1293        let mut diff_bases = HashMap::default();
1294        for (buffer_id, diff) in self.diffs.iter() {
1295            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1296        }
1297        Self {
1298            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1299            buffers,
1300            excerpts_by_path: Default::default(),
1301            paths_by_excerpt: Default::default(),
1302            diffs: diff_bases,
1303            subscriptions: Default::default(),
1304            singleton: self.singleton,
1305            capability: self.capability,
1306            history: self.history.clone(),
1307            title: self.title.clone(),
1308            buffer_changed_since_sync,
1309        }
1310    }
1311
1312    pub fn set_group_interval(&mut self, group_interval: Duration, cx: &mut Context<Self>) {
1313        self.history.set_group_interval(group_interval);
1314        if self.singleton {
1315            for BufferState { buffer, .. } in self.buffers.values() {
1316                buffer.update(cx, |buffer, _| {
1317                    buffer.set_group_interval(group_interval);
1318                });
1319            }
1320        }
1321    }
1322
1323    pub fn with_title(mut self, title: String) -> Self {
1324        self.title = Some(title);
1325        self
1326    }
1327
1328    pub fn read_only(&self) -> bool {
1329        !self.capability.editable()
1330    }
1331
1332    pub fn capability(&self) -> Capability {
1333        self.capability
1334    }
1335
1336    /// Returns an up-to-date snapshot of the MultiBuffer.
1337    #[ztracing::instrument(skip_all)]
1338    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1339        self.sync(cx);
1340        self.snapshot.borrow().clone()
1341    }
1342
1343    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1344        self.sync(cx);
1345        self.snapshot.borrow()
1346    }
1347
1348    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1349        if self.singleton {
1350            Some(self.buffers.values().next().unwrap().buffer.clone())
1351        } else {
1352            None
1353        }
1354    }
1355
1356    pub fn is_singleton(&self) -> bool {
1357        self.singleton
1358    }
1359
1360    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1361        self.subscriptions.subscribe()
1362    }
1363
1364    pub fn is_dirty(&self, cx: &App) -> bool {
1365        self.read(cx).is_dirty()
1366    }
1367
1368    pub fn has_deleted_file(&self, cx: &App) -> bool {
1369        self.read(cx).has_deleted_file()
1370    }
1371
1372    pub fn has_conflict(&self, cx: &App) -> bool {
1373        self.read(cx).has_conflict()
1374    }
1375
1376    // The `is_empty` signature doesn't match what clippy expects
1377    #[allow(clippy::len_without_is_empty)]
1378    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1379        self.read(cx).len()
1380    }
1381
1382    pub fn is_empty(&self) -> bool {
1383        self.buffers.is_empty()
1384    }
1385
1386    pub fn edit<I, S, T>(
1387        &mut self,
1388        edits: I,
1389        autoindent_mode: Option<AutoindentMode>,
1390        cx: &mut Context<Self>,
1391    ) where
1392        I: IntoIterator<Item = (Range<S>, T)>,
1393        S: ToOffset,
1394        T: Into<Arc<str>>,
1395    {
1396        self.edit_internal(edits, autoindent_mode, true, cx);
1397    }
1398
1399    pub fn edit_non_coalesce<I, S, T>(
1400        &mut self,
1401        edits: I,
1402        autoindent_mode: Option<AutoindentMode>,
1403        cx: &mut Context<Self>,
1404    ) where
1405        I: IntoIterator<Item = (Range<S>, T)>,
1406        S: ToOffset,
1407        T: Into<Arc<str>>,
1408    {
1409        self.edit_internal(edits, autoindent_mode, false, cx);
1410    }
1411
1412    fn edit_internal<I, S, T>(
1413        &mut self,
1414        edits: I,
1415        autoindent_mode: Option<AutoindentMode>,
1416        coalesce_adjacent: bool,
1417        cx: &mut Context<Self>,
1418    ) where
1419        I: IntoIterator<Item = (Range<S>, T)>,
1420        S: ToOffset,
1421        T: Into<Arc<str>>,
1422    {
1423        if self.read_only() || self.buffers.is_empty() {
1424            return;
1425        }
1426        self.sync_mut(cx);
1427        let edits = edits
1428            .into_iter()
1429            .map(|(range, new_text)| {
1430                let mut range = range.start.to_offset(self.snapshot.get_mut())
1431                    ..range.end.to_offset(self.snapshot.get_mut());
1432                if range.start > range.end {
1433                    mem::swap(&mut range.start, &mut range.end);
1434                }
1435                (range, new_text.into())
1436            })
1437            .collect::<Vec<_>>();
1438
1439        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1440
1441        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1442        fn edit_internal(
1443            this: &mut MultiBuffer,
1444            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1445            mut autoindent_mode: Option<AutoindentMode>,
1446            coalesce_adjacent: bool,
1447            cx: &mut Context<MultiBuffer>,
1448        ) {
1449            let original_indent_columns = match &mut autoindent_mode {
1450                Some(AutoindentMode::Block {
1451                    original_indent_columns,
1452                }) => mem::take(original_indent_columns),
1453                _ => Default::default(),
1454            };
1455
1456            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1457                edits,
1458                this.snapshot.get_mut(),
1459                &original_indent_columns,
1460            );
1461
1462            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1463            for (buffer_id, mut edits) in buffer_edits {
1464                buffer_ids.push(buffer_id);
1465                edits.sort_by_key(|edit| edit.range.start);
1466                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1467                    let mut edits = edits.into_iter().peekable();
1468                    let mut insertions = Vec::new();
1469                    let mut original_indent_columns = Vec::new();
1470                    let mut deletions = Vec::new();
1471                    let empty_str: Arc<str> = Arc::default();
1472                    while let Some(BufferEdit {
1473                        mut range,
1474                        mut new_text,
1475                        mut is_insertion,
1476                        original_indent_column,
1477                        excerpt_id,
1478                    }) = edits.next()
1479                    {
1480                        while let Some(BufferEdit {
1481                            range: next_range,
1482                            is_insertion: next_is_insertion,
1483                            new_text: next_new_text,
1484                            excerpt_id: next_excerpt_id,
1485                            ..
1486                        }) = edits.peek()
1487                        {
1488                            let should_coalesce = if coalesce_adjacent {
1489                                range.end >= next_range.start
1490                            } else {
1491                                range.end > next_range.start
1492                            };
1493
1494                            if should_coalesce {
1495                                range.end = cmp::max(next_range.end, range.end);
1496                                is_insertion |= *next_is_insertion;
1497                                if excerpt_id == *next_excerpt_id {
1498                                    new_text = format!("{new_text}{next_new_text}").into();
1499                                }
1500                                edits.next();
1501                            } else {
1502                                break;
1503                            }
1504                        }
1505
1506                        if is_insertion {
1507                            original_indent_columns.push(original_indent_column);
1508                            insertions.push((
1509                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1510                                new_text.clone(),
1511                            ));
1512                        } else if !range.is_empty() {
1513                            deletions.push((
1514                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1515                                empty_str.clone(),
1516                            ));
1517                        }
1518                    }
1519
1520                    let deletion_autoindent_mode =
1521                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1522                            Some(AutoindentMode::Block {
1523                                original_indent_columns: Default::default(),
1524                            })
1525                        } else {
1526                            autoindent_mode.clone()
1527                        };
1528                    let insertion_autoindent_mode =
1529                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1530                            Some(AutoindentMode::Block {
1531                                original_indent_columns,
1532                            })
1533                        } else {
1534                            autoindent_mode.clone()
1535                        };
1536
1537                    if coalesce_adjacent {
1538                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1539                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1540                    } else {
1541                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1542                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1543                    }
1544                })
1545            }
1546
1547            cx.emit(Event::ExcerptsEdited {
1548                excerpt_ids: edited_excerpt_ids,
1549                buffer_ids,
1550            });
1551        }
1552    }
1553
1554    fn convert_edits_to_buffer_edits(
1555        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1556        snapshot: &MultiBufferSnapshot,
1557        original_indent_columns: &[Option<u32>],
1558    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1559        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1560        let mut edited_excerpt_ids = Vec::new();
1561        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1562        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1563            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1564
1565            cursor.seek(&range.start);
1566            let mut start_region = cursor.region().expect("start offset out of bounds");
1567            if !start_region.is_main_buffer {
1568                cursor.next();
1569                if let Some(region) = cursor.region() {
1570                    start_region = region;
1571                } else {
1572                    continue;
1573                }
1574            }
1575
1576            if range.end < start_region.range.start {
1577                continue;
1578            }
1579
1580            let start_region = start_region.clone();
1581            if range.end > start_region.range.end {
1582                cursor.seek_forward(&range.end);
1583            }
1584            let mut end_region = cursor.region().expect("end offset out of bounds");
1585            if !end_region.is_main_buffer {
1586                cursor.prev();
1587                if let Some(region) = cursor.region() {
1588                    end_region = region;
1589                } else {
1590                    continue;
1591                }
1592            }
1593
1594            if range.start > end_region.range.end {
1595                continue;
1596            }
1597
1598            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1599            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1600            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1601                .min(start_region.buffer_range.end);
1602            let buffer_end =
1603                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1604
1605            if start_region.excerpt.id == end_region.excerpt.id {
1606                if start_region.buffer.capability == Capability::ReadWrite
1607                    && start_region.is_main_buffer
1608                {
1609                    edited_excerpt_ids.push(start_region.excerpt.id);
1610                    buffer_edits
1611                        .entry(start_region.buffer.remote_id())
1612                        .or_default()
1613                        .push(BufferEdit {
1614                            range: buffer_start..buffer_end,
1615                            new_text,
1616                            is_insertion: true,
1617                            original_indent_column,
1618                            excerpt_id: start_region.excerpt.id,
1619                        });
1620                }
1621            } else {
1622                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1623                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1624                if start_region.buffer.capability == Capability::ReadWrite
1625                    && start_region.is_main_buffer
1626                {
1627                    edited_excerpt_ids.push(start_region.excerpt.id);
1628                    buffer_edits
1629                        .entry(start_region.buffer.remote_id())
1630                        .or_default()
1631                        .push(BufferEdit {
1632                            range: start_excerpt_range,
1633                            new_text: new_text.clone(),
1634                            is_insertion: true,
1635                            original_indent_column,
1636                            excerpt_id: start_region.excerpt.id,
1637                        });
1638                }
1639                let excerpt_id = end_region.excerpt.id;
1640                if end_region.buffer.capability == Capability::ReadWrite
1641                    && end_region.is_main_buffer
1642                {
1643                    edited_excerpt_ids.push(excerpt_id);
1644                    buffer_edits
1645                        .entry(end_region.buffer.remote_id())
1646                        .or_default()
1647                        .push(BufferEdit {
1648                            range: end_excerpt_range,
1649                            new_text: new_text.clone(),
1650                            is_insertion: false,
1651                            original_indent_column,
1652                            excerpt_id,
1653                        });
1654                }
1655
1656                cursor.seek(&range.start);
1657                cursor.next_excerpt();
1658                while let Some(region) = cursor.region() {
1659                    if region.excerpt.id == excerpt_id {
1660                        break;
1661                    }
1662                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1663                        edited_excerpt_ids.push(region.excerpt.id);
1664                        buffer_edits
1665                            .entry(region.buffer.remote_id())
1666                            .or_default()
1667                            .push(BufferEdit {
1668                                range: region.buffer_range.clone(),
1669                                new_text: new_text.clone(),
1670                                is_insertion: false,
1671                                original_indent_column,
1672                                excerpt_id: region.excerpt.id,
1673                            });
1674                    }
1675                    cursor.next_excerpt();
1676                }
1677            }
1678        }
1679        (buffer_edits, edited_excerpt_ids)
1680    }
1681
1682    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1683    where
1684        I: IntoIterator<Item = Range<S>>,
1685        S: ToOffset,
1686    {
1687        if self.read_only() || self.buffers.is_empty() {
1688            return;
1689        }
1690        self.sync_mut(cx);
1691        let empty = Arc::<str>::from("");
1692        let edits = ranges
1693            .into_iter()
1694            .map(|range| {
1695                let mut range = range.start.to_offset(self.snapshot.get_mut())
1696                    ..range.end.to_offset(&self.snapshot.get_mut());
1697                if range.start > range.end {
1698                    mem::swap(&mut range.start, &mut range.end);
1699                }
1700                (range, empty.clone())
1701            })
1702            .collect::<Vec<_>>();
1703
1704        return autoindent_ranges_internal(self, edits, cx);
1705
1706        fn autoindent_ranges_internal(
1707            this: &mut MultiBuffer,
1708            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1709            cx: &mut Context<MultiBuffer>,
1710        ) {
1711            let (buffer_edits, edited_excerpt_ids) =
1712                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1713
1714            let mut buffer_ids = Vec::new();
1715            for (buffer_id, mut edits) in buffer_edits {
1716                buffer_ids.push(buffer_id);
1717                edits.sort_unstable_by_key(|edit| edit.range.start);
1718
1719                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1720                for edit in edits {
1721                    if let Some(last_range) = ranges.last_mut()
1722                        && edit.range.start <= last_range.end
1723                    {
1724                        last_range.end = last_range.end.max(edit.range.end);
1725                        continue;
1726                    }
1727                    ranges.push(edit.range);
1728                }
1729
1730                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1731                    buffer.autoindent_ranges(ranges, cx);
1732                })
1733            }
1734
1735            cx.emit(Event::ExcerptsEdited {
1736                excerpt_ids: edited_excerpt_ids,
1737                buffer_ids,
1738            });
1739        }
1740    }
1741
1742    pub fn set_active_selections(
1743        &self,
1744        selections: &[Selection<Anchor>],
1745        line_mode: bool,
1746        cursor_shape: CursorShape,
1747        cx: &mut Context<Self>,
1748    ) {
1749        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1750            Default::default();
1751        let snapshot = self.read(cx);
1752        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1753        for selection in selections {
1754            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1755            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1756
1757            cursor.seek(&Some(start_locator), Bias::Left);
1758            while let Some(excerpt) = cursor.item()
1759                && excerpt.locator <= *end_locator
1760            {
1761                let mut start = excerpt.range.context.start;
1762                let mut end = excerpt.range.context.end;
1763                if excerpt.id == selection.start.excerpt_id {
1764                    start = selection.start.text_anchor;
1765                }
1766                if excerpt.id == selection.end.excerpt_id {
1767                    end = selection.end.text_anchor;
1768                }
1769                selections_by_buffer
1770                    .entry(excerpt.buffer_id)
1771                    .or_default()
1772                    .push(Selection {
1773                        id: selection.id,
1774                        start,
1775                        end,
1776                        reversed: selection.reversed,
1777                        goal: selection.goal,
1778                    });
1779
1780                cursor.next();
1781            }
1782        }
1783
1784        for (buffer_id, buffer_state) in self.buffers.iter() {
1785            if !selections_by_buffer.contains_key(buffer_id) {
1786                buffer_state
1787                    .buffer
1788                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1789            }
1790        }
1791
1792        for (buffer_id, mut selections) in selections_by_buffer {
1793            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1794                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1795                let mut selections = selections.into_iter().peekable();
1796                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1797                    let mut selection = selections.next()?;
1798                    while let Some(next_selection) = selections.peek() {
1799                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1800                            let next_selection = selections.next().unwrap();
1801                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1802                                selection.end = next_selection.end;
1803                            }
1804                        } else {
1805                            break;
1806                        }
1807                    }
1808                    Some(selection)
1809                }));
1810                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1811            });
1812        }
1813    }
1814
1815    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1816        for buffer in self.buffers.values() {
1817            buffer
1818                .buffer
1819                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1820        }
1821    }
1822
1823    #[instrument(skip_all)]
1824    fn merge_excerpt_ranges<'a>(
1825        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1826    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1827        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1828        let mut counts: Vec<usize> = Vec::new();
1829        for range in expanded_ranges {
1830            if let Some(last_range) = merged_ranges.last_mut() {
1831                assert!(
1832                    last_range.context.start <= range.context.start,
1833                    "ranges must be sorted: {last_range:?} <= {range:?}"
1834                );
1835                if last_range.context.end >= range.context.start
1836                    || last_range.context.end.row + 1 == range.context.start.row
1837                {
1838                    last_range.context.end = range.context.end.max(last_range.context.end);
1839                    *counts.last_mut().unwrap() += 1;
1840                    continue;
1841                }
1842            }
1843            merged_ranges.push(range.clone());
1844            counts.push(1);
1845        }
1846        (merged_ranges, counts)
1847    }
1848
1849    pub fn insert_excerpts_after<O>(
1850        &mut self,
1851        prev_excerpt_id: ExcerptId,
1852        buffer: Entity<Buffer>,
1853        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1854        cx: &mut Context<Self>,
1855    ) -> Vec<ExcerptId>
1856    where
1857        O: text::ToOffset,
1858    {
1859        let mut ids = Vec::new();
1860        let mut next_excerpt_id =
1861            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1862                last_entry.id.0 + 1
1863            } else {
1864                1
1865            };
1866        self.insert_excerpts_with_ids_after(
1867            prev_excerpt_id,
1868            buffer,
1869            ranges.into_iter().map(|range| {
1870                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1871                ids.push(id);
1872                (id, range)
1873            }),
1874            cx,
1875        );
1876        ids
1877    }
1878
1879    pub fn insert_excerpts_with_ids_after<O>(
1880        &mut self,
1881        prev_excerpt_id: ExcerptId,
1882        buffer: Entity<Buffer>,
1883        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1884        cx: &mut Context<Self>,
1885    ) where
1886        O: text::ToOffset,
1887    {
1888        assert_eq!(self.history.transaction_depth(), 0);
1889        let mut ranges = ranges.into_iter().peekable();
1890        if ranges.peek().is_none() {
1891            return Default::default();
1892        }
1893
1894        self.sync_mut(cx);
1895
1896        let buffer_snapshot = buffer.read(cx).snapshot();
1897        let buffer_id = buffer_snapshot.remote_id();
1898
1899        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1900            self.buffer_changed_since_sync.replace(true);
1901            buffer.update(cx, |buffer, _| {
1902                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1903            });
1904            BufferState {
1905                last_version: RefCell::new(buffer_snapshot.version().clone()),
1906                last_non_text_state_update_count: Cell::new(
1907                    buffer_snapshot.non_text_state_update_count(),
1908                ),
1909                excerpts: Default::default(),
1910                _subscriptions: [
1911                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1912                    cx.subscribe(&buffer, Self::on_buffer_event),
1913                ],
1914                buffer: buffer.clone(),
1915            }
1916        });
1917
1918        let mut snapshot = self.snapshot.get_mut();
1919
1920        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1921        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1922        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1923        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1924        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1925
1926        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1927        new_excerpts.update_last(
1928            |excerpt| {
1929                excerpt.has_trailing_newline = true;
1930            },
1931            (),
1932        );
1933
1934        let next_locator = if let Some(excerpt) = cursor.item() {
1935            excerpt.locator.clone()
1936        } else {
1937            Locator::max()
1938        };
1939
1940        let mut excerpts = Vec::new();
1941        let buffer_snapshot = Arc::new(buffer_snapshot);
1942        while let Some((id, range)) = ranges.next() {
1943            let locator = Locator::between(&prev_locator, &next_locator);
1944            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1945                buffer_state.excerpts.insert(ix, locator.clone());
1946            }
1947            let range = ExcerptRange {
1948                context: buffer_snapshot.anchor_before(&range.context.start)
1949                    ..buffer_snapshot.anchor_after(&range.context.end),
1950                primary: buffer_snapshot.anchor_before(&range.primary.start)
1951                    ..buffer_snapshot.anchor_after(&range.primary.end),
1952            };
1953            excerpts.push((id, range.clone()));
1954            let excerpt = Excerpt::new(
1955                id,
1956                locator.clone(),
1957                buffer_id,
1958                buffer_snapshot.clone(),
1959                range,
1960                ranges.peek().is_some() || cursor.item().is_some(),
1961            );
1962            new_excerpts.push(excerpt, ());
1963            prev_locator = locator.clone();
1964
1965            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1966                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1967            }
1968            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1969        }
1970        snapshot
1971            .buffer_locators
1972            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1973
1974        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1975
1976        let suffix = cursor.suffix();
1977        let changed_trailing_excerpt = suffix.is_empty();
1978        new_excerpts.append(suffix, ());
1979        drop(cursor);
1980        snapshot.excerpts = new_excerpts;
1981        snapshot.excerpt_ids = new_excerpt_ids;
1982        if changed_trailing_excerpt {
1983            snapshot.trailing_excerpt_update_count += 1;
1984        }
1985
1986        let edits = Self::sync_diff_transforms(
1987            &mut snapshot,
1988            vec![Edit {
1989                old: edit_start..edit_start,
1990                new: edit_start..edit_end,
1991            }],
1992            DiffChangeKind::BufferEdited,
1993        );
1994        if !edits.is_empty() {
1995            self.subscriptions.publish(edits);
1996        }
1997
1998        cx.emit(Event::Edited {
1999            edited_buffer: None,
2000            is_local: true,
2001        });
2002        cx.emit(Event::ExcerptsAdded {
2003            buffer,
2004            predecessor: prev_excerpt_id,
2005            excerpts,
2006        });
2007        cx.notify();
2008    }
2009
2010    pub fn clear(&mut self, cx: &mut Context<Self>) {
2011        self.sync_mut(cx);
2012        let ids = self.excerpt_ids();
2013        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
2014        self.excerpts_by_path.clear();
2015        self.paths_by_excerpt.clear();
2016        let MultiBufferSnapshot {
2017            excerpts,
2018            buffer_locators,
2019            diffs: _,
2020            diff_transforms: _,
2021            non_text_state_update_count: _,
2022            edit_count: _,
2023            is_dirty,
2024            has_deleted_file,
2025            has_conflict,
2026            has_inverted_diff,
2027            singleton: _,
2028            excerpt_ids: _,
2029            replaced_excerpts,
2030            trailing_excerpt_update_count,
2031            all_diff_hunks_expanded: _,
2032            show_deleted_hunks: _,
2033            use_extended_diff_range: _,
2034            show_headers: _,
2035        } = self.snapshot.get_mut();
2036        buffer_locators.clear();
2037        let start = ExcerptDimension(MultiBufferOffset::ZERO);
2038        let prev_len = ExcerptDimension(excerpts.summary().text.len);
2039        *excerpts = Default::default();
2040        *trailing_excerpt_update_count += 1;
2041        *is_dirty = false;
2042        *has_deleted_file = false;
2043        *has_conflict = false;
2044        *has_inverted_diff = false;
2045        match Arc::get_mut(replaced_excerpts) {
2046            Some(replaced_excerpts) => replaced_excerpts.clear(),
2047            None => *replaced_excerpts = Default::default(),
2048        }
2049
2050        let edits = Self::sync_diff_transforms(
2051            self.snapshot.get_mut(),
2052            vec![Edit {
2053                old: start..prev_len,
2054                new: start..start,
2055            }],
2056            DiffChangeKind::BufferEdited,
2057        );
2058        if !edits.is_empty() {
2059            self.subscriptions.publish(edits);
2060        }
2061        cx.emit(Event::Edited {
2062            edited_buffer: None,
2063            is_local: true,
2064        });
2065        cx.emit(Event::ExcerptsRemoved {
2066            ids,
2067            removed_buffer_ids,
2068        });
2069        cx.notify();
2070    }
2071
2072    #[ztracing::instrument(skip_all)]
2073    pub fn excerpts_for_buffer(
2074        &self,
2075        buffer_id: BufferId,
2076        cx: &App,
2077    ) -> Vec<(ExcerptId, Arc<BufferSnapshot>, ExcerptRange<text::Anchor>)> {
2078        let mut excerpts = Vec::new();
2079        let snapshot = self.read(cx);
2080        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
2081        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
2082            for locator in &**locators {
2083                cursor.seek_forward(&Some(locator), Bias::Left);
2084                if let Some(excerpt) = cursor.item()
2085                    && excerpt.locator == *locator
2086                {
2087                    excerpts.push((excerpt.id, excerpt.buffer.clone(), excerpt.range.clone()));
2088                }
2089            }
2090        }
2091
2092        excerpts
2093    }
2094
2095    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2096        let snapshot = self.read(cx);
2097        let mut excerpts = snapshot
2098            .excerpts
2099            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2100        let mut diff_transforms = snapshot
2101            .diff_transforms
2102            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2103        diff_transforms.next();
2104        let locators = snapshot
2105            .buffer_locators
2106            .get(&buffer_id)
2107            .into_iter()
2108            .flat_map(|v| &**v);
2109        let mut result = Vec::new();
2110        for locator in locators {
2111            excerpts.seek_forward(&Some(locator), Bias::Left);
2112            if let Some(excerpt) = excerpts.item()
2113                && excerpt.locator == *locator
2114            {
2115                let excerpt_start = excerpts.start().1;
2116                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2117
2118                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2119                let overshoot = excerpt_start - diff_transforms.start().0;
2120                let start = diff_transforms.start().1 + overshoot;
2121
2122                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2123                let overshoot = excerpt_end - diff_transforms.start().0;
2124                let end = diff_transforms.start().1 + overshoot;
2125
2126                result.push(start.0..end.0)
2127            }
2128        }
2129        result
2130    }
2131
2132    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2133        self.snapshot
2134            .borrow()
2135            .excerpts
2136            .iter()
2137            .map(|entry| entry.buffer_id)
2138            .collect()
2139    }
2140
2141    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2142        let snapshot = self.snapshot.borrow();
2143        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2144        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2145        ids
2146    }
2147
2148    pub fn excerpt_containing(
2149        &self,
2150        position: impl ToOffset,
2151        cx: &App,
2152    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2153        let snapshot = self.read(cx);
2154        let offset = position.to_offset(&snapshot);
2155
2156        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2157        cursor.seek(&offset);
2158        cursor
2159            .excerpt()
2160            .or_else(|| snapshot.excerpts.last())
2161            .map(|excerpt| {
2162                (
2163                    excerpt.id,
2164                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2165                    excerpt.range.context.clone(),
2166                )
2167            })
2168    }
2169
2170    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2171        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2172            self.buffer(buffer_id)
2173        } else {
2174            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2175            Some(buffer)
2176        }
2177    }
2178
2179    // If point is at the end of the buffer, the last excerpt is returned
2180    pub fn point_to_buffer_offset<T: ToOffset>(
2181        &self,
2182        point: T,
2183        cx: &App,
2184    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2185        let snapshot = self.read(cx);
2186        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2187        Some((
2188            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2189            offset,
2190        ))
2191    }
2192
2193    // If point is at the end of the buffer, the last excerpt is returned
2194    pub fn point_to_buffer_point<T: ToPoint>(
2195        &self,
2196        point: T,
2197        cx: &App,
2198    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2199        let snapshot = self.read(cx);
2200        let (buffer, point, is_main_buffer) =
2201            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2202        Some((
2203            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2204            point,
2205            is_main_buffer,
2206        ))
2207    }
2208
2209    pub fn buffer_point_to_anchor(
2210        &self,
2211        // todo(lw): We shouldn't need this?
2212        buffer: &Entity<Buffer>,
2213        point: Point,
2214        cx: &App,
2215    ) -> Option<Anchor> {
2216        let mut found = None;
2217        let snapshot = buffer.read(cx).snapshot();
2218        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2219            let start = range.context.start.to_point(&snapshot);
2220            let end = range.context.end.to_point(&snapshot);
2221            if start <= point && point < end {
2222                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2223                break;
2224            }
2225            if point < start {
2226                found = Some((start, excerpt_id));
2227            }
2228            if point >= end {
2229                found = Some((end, excerpt_id));
2230            }
2231        }
2232
2233        found.map(|(point, excerpt_id)| {
2234            let text_anchor = snapshot.anchor_after(point);
2235            Anchor::in_buffer(excerpt_id, text_anchor)
2236        })
2237    }
2238
2239    pub fn buffer_anchor_to_anchor(
2240        &self,
2241        // todo(lw): We shouldn't need this?
2242        buffer: &Entity<Buffer>,
2243        anchor: text::Anchor,
2244        cx: &App,
2245    ) -> Option<Anchor> {
2246        let snapshot = buffer.read(cx).snapshot();
2247        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2248            if range.context.start.cmp(&anchor, &snapshot).is_le()
2249                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2250            {
2251                return Some(Anchor::in_buffer(excerpt_id, anchor));
2252            }
2253        }
2254
2255        None
2256    }
2257
2258    pub fn merge_excerpts(
2259        &mut self,
2260        excerpt_ids: &[ExcerptId],
2261        cx: &mut Context<Self>,
2262    ) -> ExcerptId {
2263        debug_assert!(!excerpt_ids.is_empty());
2264        if excerpt_ids.len() == 1 {
2265            return excerpt_ids[0];
2266        }
2267
2268        let snapshot = self.snapshot(cx);
2269
2270        let first_range = snapshot
2271            .context_range_for_excerpt(excerpt_ids[0])
2272            .expect("first excerpt must exist");
2273        let last_range = snapshot
2274            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2275            .expect("last excerpt must exist");
2276
2277        let union_range = first_range.start..last_range.end;
2278
2279        drop(snapshot);
2280
2281        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2282        let removed = &excerpt_ids[1..];
2283        for &excerpt_id in removed {
2284            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2285                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2286                    excerpt_list.retain(|id| *id != excerpt_id);
2287                    if excerpt_list.is_empty() {
2288                        let path = path.clone();
2289                        self.excerpts_by_path.remove(&path);
2290                    }
2291                }
2292            }
2293        }
2294        self.remove_excerpts(removed.iter().copied(), cx);
2295
2296        excerpt_ids[0]
2297    }
2298
2299    pub fn remove_excerpts(
2300        &mut self,
2301        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2302        cx: &mut Context<Self>,
2303    ) {
2304        self.sync_mut(cx);
2305        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2306        if ids.is_empty() {
2307            return;
2308        }
2309        self.buffer_changed_since_sync.replace(true);
2310
2311        let mut snapshot = self.snapshot.get_mut();
2312        let mut new_excerpts = SumTree::default();
2313        let mut cursor = snapshot
2314            .excerpts
2315            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2316        let mut edits = Vec::new();
2317        let mut excerpt_ids = ids.iter().copied().peekable();
2318        let mut removed_buffer_ids = Vec::new();
2319        let mut removed_excerpts_for_buffers = HashSet::default();
2320
2321        while let Some(excerpt_id) = excerpt_ids.next() {
2322            self.paths_by_excerpt.remove(&excerpt_id);
2323            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2324            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2325            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2326
2327            if let Some(mut excerpt) = cursor.item() {
2328                if excerpt.id != excerpt_id {
2329                    continue;
2330                }
2331                let mut old_start = cursor.start().1;
2332
2333                // Skip over the removed excerpt.
2334                'remove_excerpts: loop {
2335                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2336                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2337                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2338                        if buffer_state.excerpts.is_empty() {
2339                            log::debug!(
2340                                "removing buffer and diff for buffer {}",
2341                                excerpt.buffer_id
2342                            );
2343                            self.buffers.remove(&excerpt.buffer_id);
2344                            removed_buffer_ids.push(excerpt.buffer_id);
2345                        }
2346                    }
2347                    cursor.next();
2348
2349                    // Skip over any subsequent excerpts that are also removed.
2350                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2351                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2352                        if let Some(next_excerpt) = cursor.item()
2353                            && next_excerpt.locator == *next_locator
2354                        {
2355                            excerpt_ids.next();
2356                            excerpt = next_excerpt;
2357                            continue 'remove_excerpts;
2358                        }
2359                    }
2360
2361                    break;
2362                }
2363
2364                // When removing the last excerpt, remove the trailing newline from
2365                // the previous excerpt.
2366                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2367                    old_start -= 1;
2368                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2369                }
2370
2371                // Push an edit for the removal of this run of excerpts.
2372                let old_end = cursor.start().1;
2373                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2374                edits.push(Edit {
2375                    old: old_start..old_end,
2376                    new: new_start..new_start,
2377                });
2378            }
2379        }
2380        let suffix = cursor.suffix();
2381        let changed_trailing_excerpt = suffix.is_empty();
2382        new_excerpts.append(suffix, ());
2383        drop(cursor);
2384        for buffer_id in removed_excerpts_for_buffers {
2385            match self.buffers.get(&buffer_id) {
2386                Some(buffer_state) => {
2387                    snapshot
2388                        .buffer_locators
2389                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2390                }
2391                None => {
2392                    snapshot.buffer_locators.remove(&buffer_id);
2393                }
2394            }
2395        }
2396        snapshot.excerpts = new_excerpts;
2397        for buffer_id in &removed_buffer_ids {
2398            self.diffs.remove(buffer_id);
2399            remove_diff_state(&mut snapshot.diffs, *buffer_id);
2400        }
2401
2402        if !removed_buffer_ids.is_empty() {
2403            snapshot.has_inverted_diff =
2404                snapshot.diffs.iter().any(|diff| diff.main_buffer.is_some());
2405        }
2406
2407        if changed_trailing_excerpt {
2408            snapshot.trailing_excerpt_update_count += 1;
2409        }
2410
2411        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2412        if !edits.is_empty() {
2413            self.subscriptions.publish(edits);
2414        }
2415        cx.emit(Event::Edited {
2416            edited_buffer: None,
2417            is_local: true,
2418        });
2419        cx.emit(Event::ExcerptsRemoved {
2420            ids,
2421            removed_buffer_ids,
2422        });
2423        cx.notify();
2424    }
2425
2426    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2427        &self,
2428        anchors: Anchors,
2429        cx: &mut Context<Self>,
2430    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2431        let mut error = None;
2432        let mut futures = Vec::new();
2433        for anchor in anchors {
2434            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2435                if let Some(buffer) = self.buffers.get(&buffer_id) {
2436                    buffer.buffer.update(cx, |buffer, _| {
2437                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2438                    });
2439                } else {
2440                    error = Some(anyhow!(
2441                        "buffer {buffer_id} is not part of this multi-buffer"
2442                    ));
2443                    break;
2444                }
2445            }
2446        }
2447        async move {
2448            if let Some(error) = error {
2449                Err(error)?;
2450            }
2451            for future in futures {
2452                future.await?;
2453            }
2454            Ok(())
2455        }
2456    }
2457
2458    pub fn text_anchor_for_position<T: ToOffset>(
2459        &self,
2460        position: T,
2461        cx: &App,
2462    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2463        let snapshot = self.read(cx);
2464        let anchor = snapshot.anchor_before(position);
2465        let buffer = self
2466            .buffers
2467            .get(&anchor.text_anchor.buffer_id?)?
2468            .buffer
2469            .clone();
2470        Some((buffer, anchor.text_anchor))
2471    }
2472
2473    fn on_buffer_event(
2474        &mut self,
2475        buffer: Entity<Buffer>,
2476        event: &language::BufferEvent,
2477        cx: &mut Context<Self>,
2478    ) {
2479        use language::BufferEvent;
2480        let buffer_id = buffer.read(cx).remote_id();
2481        cx.emit(match event {
2482            &BufferEvent::Edited { is_local } => Event::Edited {
2483                edited_buffer: Some(buffer),
2484                is_local,
2485            },
2486            BufferEvent::DirtyChanged => Event::DirtyChanged,
2487            BufferEvent::Saved => Event::Saved,
2488            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2489            BufferEvent::Reloaded => Event::Reloaded,
2490            BufferEvent::LanguageChanged(has_language) => {
2491                Event::LanguageChanged(buffer_id, *has_language)
2492            }
2493            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2494            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2495            BufferEvent::CapabilityChanged => {
2496                self.capability = buffer.read(cx).capability();
2497                return;
2498            }
2499            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2500        });
2501    }
2502
2503    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2504        let diff = diff.read(cx);
2505        let buffer_id = diff.buffer_id;
2506        let diff = DiffStateSnapshot {
2507            buffer_id,
2508            diff: diff.snapshot(cx),
2509            main_buffer: None,
2510        };
2511        self.snapshot.get_mut().diffs.insert_or_replace(diff, ());
2512    }
2513
2514    fn inverted_buffer_diff_language_changed(
2515        &mut self,
2516        diff: Entity<BufferDiff>,
2517        main_buffer: Entity<language::Buffer>,
2518        cx: &mut Context<Self>,
2519    ) {
2520        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2521        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2522        let diff = diff.read(cx);
2523        let diff = DiffStateSnapshot {
2524            buffer_id: base_text_buffer_id,
2525            diff: diff.snapshot(cx),
2526            main_buffer: Some(main_buffer_snapshot),
2527        };
2528        self.snapshot.get_mut().diffs.insert_or_replace(diff, ());
2529    }
2530
2531    fn buffer_diff_changed(
2532        &mut self,
2533        diff: Entity<BufferDiff>,
2534        range: Range<text::Anchor>,
2535        cx: &mut Context<Self>,
2536    ) {
2537        self.sync_mut(cx);
2538
2539        let diff = diff.read(cx);
2540        let buffer_id = diff.buffer_id;
2541
2542        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2543            return;
2544        };
2545        let new_diff = DiffStateSnapshot {
2546            buffer_id,
2547            diff: diff.snapshot(cx),
2548            main_buffer: None,
2549        };
2550        let mut snapshot = self.snapshot.get_mut();
2551        let base_text_changed = find_diff_state(&snapshot.diffs, buffer_id)
2552            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2553        snapshot.diffs.insert_or_replace(new_diff, ());
2554
2555        let buffer = buffer_state.buffer.read(cx);
2556        let diff_change_range = range.to_offset(buffer);
2557
2558        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2559        let edits = Self::sync_diff_transforms(
2560            &mut snapshot,
2561            excerpt_edits,
2562            DiffChangeKind::DiffUpdated {
2563                base_changed: base_text_changed,
2564            },
2565        );
2566        if !edits.is_empty() {
2567            self.subscriptions.publish(edits);
2568        }
2569        cx.emit(Event::Edited {
2570            edited_buffer: None,
2571            is_local: true,
2572        });
2573    }
2574
2575    fn inverted_buffer_diff_changed(
2576        &mut self,
2577        diff: Entity<BufferDiff>,
2578        main_buffer: Entity<language::Buffer>,
2579        diff_change_range: Range<usize>,
2580        cx: &mut Context<Self>,
2581    ) {
2582        self.sync_mut(cx);
2583
2584        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2585        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2586            return;
2587        };
2588
2589        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2590        let diff = diff.read(cx);
2591        let new_diff = DiffStateSnapshot {
2592            buffer_id: base_text_buffer_id,
2593            diff: diff.snapshot(cx),
2594            main_buffer: Some(main_buffer_snapshot),
2595        };
2596        let mut snapshot = self.snapshot.get_mut();
2597        snapshot.diffs.insert_or_replace(new_diff, ());
2598
2599        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2600        let edits = Self::sync_diff_transforms(
2601            &mut snapshot,
2602            excerpt_edits,
2603            DiffChangeKind::DiffUpdated {
2604                // We don't read this field for inverted diffs.
2605                base_changed: false,
2606            },
2607        );
2608        if !edits.is_empty() {
2609            self.subscriptions.publish(edits);
2610        }
2611        cx.emit(Event::Edited {
2612            edited_buffer: None,
2613            is_local: true,
2614        });
2615    }
2616
2617    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2618        self.buffers.values().map(|state| state.buffer.clone())
2619    }
2620
2621    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2622        self.all_buffers_iter().collect()
2623    }
2624
2625    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2626        self.buffers.keys().copied()
2627    }
2628
2629    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2630        self.all_buffer_ids_iter().collect()
2631    }
2632
2633    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2634        self.buffers
2635            .get(&buffer_id)
2636            .map(|state| state.buffer.clone())
2637    }
2638
2639    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2640        self.point_to_buffer_offset(point, cx)
2641            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2642    }
2643
2644    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2645        let buffer_id = self
2646            .snapshot
2647            .borrow()
2648            .excerpts
2649            .first()
2650            .map(|excerpt| excerpt.buffer.remote_id());
2651        buffer_id
2652            .and_then(|buffer_id| self.buffer(buffer_id))
2653            .map(|buffer| LanguageSettings::for_buffer(&buffer.read(cx), cx))
2654            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2655    }
2656
2657    pub fn language_settings_at<'a, T: ToOffset>(
2658        &'a self,
2659        point: T,
2660        cx: &'a App,
2661    ) -> Cow<'a, LanguageSettings> {
2662        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2663            LanguageSettings::for_buffer_at(buffer.read(cx), offset, cx)
2664        } else {
2665            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
2666        }
2667    }
2668
2669    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2670        self.buffers.values().for_each(|state| f(&state.buffer))
2671    }
2672
2673    pub fn explicit_title(&self) -> Option<&str> {
2674        self.title.as_deref()
2675    }
2676
2677    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2678        if let Some(title) = self.title.as_ref() {
2679            return title.into();
2680        }
2681
2682        if let Some(buffer) = self.as_singleton() {
2683            let buffer = buffer.read(cx);
2684
2685            if let Some(file) = buffer.file() {
2686                return file.file_name(cx).into();
2687            }
2688
2689            if let Some(title) = self.buffer_content_title(buffer) {
2690                return title;
2691            }
2692        };
2693
2694        "untitled".into()
2695    }
2696
2697    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2698        let mut is_leading_whitespace = true;
2699        let mut count = 0;
2700        let mut prev_was_space = false;
2701        let mut title = String::new();
2702
2703        for ch in buffer.snapshot().chars() {
2704            if is_leading_whitespace && ch.is_whitespace() {
2705                continue;
2706            }
2707
2708            is_leading_whitespace = false;
2709
2710            if ch == '\n' || count >= 40 {
2711                break;
2712            }
2713
2714            if ch.is_whitespace() {
2715                if !prev_was_space {
2716                    title.push(' ');
2717                    count += 1;
2718                    prev_was_space = true;
2719                }
2720            } else {
2721                title.push(ch);
2722                count += 1;
2723                prev_was_space = false;
2724            }
2725        }
2726
2727        let title = title.trim_end().to_string();
2728
2729        if title.is_empty() {
2730            return None;
2731        }
2732
2733        Some(title.into())
2734    }
2735
2736    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2737        self.title = Some(title);
2738        cx.notify();
2739    }
2740
2741    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2742    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2743        for buffer_state in self.buffers.values() {
2744            buffer_state
2745                .buffer
2746                .update(cx, |buffer, _cx| buffer.refresh_preview());
2747        }
2748    }
2749
2750    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2751    pub fn preserve_preview(&self, cx: &App) -> bool {
2752        self.buffers
2753            .values()
2754            .all(|state| state.buffer.read(cx).preserve_preview())
2755    }
2756
2757    #[cfg(any(test, feature = "test-support"))]
2758    pub fn is_parsing(&self, cx: &App) -> bool {
2759        self.as_singleton().unwrap().read(cx).is_parsing()
2760    }
2761
2762    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2763        let buffer_id = diff.read(cx).buffer_id;
2764
2765        if let Some(existing_diff) = self.diff_for(buffer_id)
2766            && diff.entity_id() == existing_diff.entity_id()
2767        {
2768            return;
2769        }
2770
2771        self.buffer_diff_changed(
2772            diff.clone(),
2773            text::Anchor::min_max_range_for_buffer(buffer_id),
2774            cx,
2775        );
2776        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2777    }
2778
2779    pub fn add_inverted_diff(
2780        &mut self,
2781        diff: Entity<BufferDiff>,
2782        main_buffer: Entity<language::Buffer>,
2783        cx: &mut Context<Self>,
2784    ) {
2785        let snapshot = diff.read(cx).base_text(cx);
2786        let base_text_buffer_id = snapshot.remote_id();
2787        let diff_change_range = 0..snapshot.len();
2788        self.snapshot.get_mut().has_inverted_diff = true;
2789        self.inverted_buffer_diff_changed(diff.clone(), main_buffer.clone(), diff_change_range, cx);
2790        self.diffs.insert(
2791            base_text_buffer_id,
2792            DiffState::new_inverted(diff, main_buffer, cx),
2793        );
2794    }
2795
2796    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2797        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2798    }
2799
2800    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2801        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2802    }
2803
2804    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2805        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2806    }
2807
2808    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2809        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2810        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2811    }
2812
2813    pub fn all_diff_hunks_expanded(&self) -> bool {
2814        self.snapshot.borrow().all_diff_hunks_expanded
2815    }
2816
2817    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2818        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2819        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2820    }
2821
2822    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2823        self.snapshot.get_mut().show_deleted_hunks = show;
2824
2825        self.sync_mut(cx);
2826
2827        let old_len = self.snapshot.borrow().len();
2828
2829        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2830        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2831
2832        let new_len = self.snapshot.borrow().len();
2833
2834        self.subscriptions.publish(vec![Edit {
2835            old: MultiBufferOffset(0)..old_len,
2836            new: MultiBufferOffset(0)..new_len,
2837        }]);
2838
2839        cx.emit(Event::DiffHunksToggled);
2840        cx.emit(Event::Edited {
2841            edited_buffer: None,
2842            is_local: true,
2843        });
2844    }
2845
2846    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2847        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2848    }
2849
2850    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2851        self.read(cx)
2852            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2853            .nth(1)
2854            .is_some()
2855    }
2856
2857    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2858        let snapshot = self.read(cx);
2859        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2860        let offset_range = range.to_offset(&snapshot);
2861        cursor.seek(&offset_range.start, Bias::Left);
2862        while let Some(item) = cursor.item() {
2863            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2864                break;
2865            }
2866            if item.hunk_info().is_some() {
2867                return true;
2868            }
2869            cursor.next();
2870        }
2871        false
2872    }
2873
2874    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2875        let snapshot = self.read(cx);
2876        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2877        for range in ranges {
2878            let range = range.to_point(&snapshot);
2879            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2880            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2881                .min(snapshot.len());
2882            cursor.seek(&start, Bias::Right);
2883            while let Some(item) = cursor.item() {
2884                if *cursor.start() >= end {
2885                    break;
2886                }
2887                if item.hunk_info().is_some() {
2888                    return true;
2889                }
2890                cursor.next();
2891            }
2892        }
2893        false
2894    }
2895
2896    pub fn expand_or_collapse_diff_hunks_inner(
2897        &mut self,
2898        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2899        expand: bool,
2900        cx: &mut Context<Self>,
2901    ) -> Vec<Edit<MultiBufferOffset>> {
2902        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2903            return Vec::new();
2904        }
2905        self.sync_mut(cx);
2906        let mut snapshot = self.snapshot.get_mut();
2907        let mut excerpt_edits = Vec::new();
2908        let mut last_hunk_row = None;
2909        for (range, end_excerpt_id) in ranges {
2910            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2911                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2912                    continue;
2913                }
2914                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2915                    continue;
2916                }
2917                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2918                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2919                let start = snapshot.excerpt_offset_for_anchor(&start);
2920                let end = snapshot.excerpt_offset_for_anchor(&end);
2921                last_hunk_row = Some(diff_hunk.row_range.start);
2922                excerpt_edits.push(text::Edit {
2923                    old: start..end,
2924                    new: start..end,
2925                });
2926            }
2927        }
2928
2929        Self::sync_diff_transforms(
2930            &mut snapshot,
2931            excerpt_edits,
2932            DiffChangeKind::ExpandOrCollapseHunks { expand },
2933        )
2934    }
2935
2936    pub fn expand_or_collapse_diff_hunks(
2937        &mut self,
2938        ranges: Vec<Range<Anchor>>,
2939        expand: bool,
2940        cx: &mut Context<Self>,
2941    ) {
2942        let snapshot = self.snapshot.borrow().clone();
2943        let ranges = ranges.iter().map(move |range| {
2944            let end_excerpt_id = range.end.excerpt_id;
2945            let range = range.to_point(&snapshot);
2946            let mut peek_end = range.end;
2947            if range.end.row < snapshot.max_row().0 {
2948                peek_end = Point::new(range.end.row + 1, 0);
2949            };
2950            (range.start..peek_end, end_excerpt_id)
2951        });
2952        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2953        if !edits.is_empty() {
2954            self.subscriptions.publish(edits);
2955        }
2956        cx.emit(Event::DiffHunksToggled);
2957        cx.emit(Event::Edited {
2958            edited_buffer: None,
2959            is_local: true,
2960        });
2961    }
2962
2963    pub fn resize_excerpt(
2964        &mut self,
2965        id: ExcerptId,
2966        range: Range<text::Anchor>,
2967        cx: &mut Context<Self>,
2968    ) {
2969        self.sync_mut(cx);
2970
2971        let mut snapshot = self.snapshot.get_mut();
2972        let locator = snapshot.excerpt_locator_for_id(id);
2973        let mut new_excerpts = SumTree::default();
2974        let mut cursor = snapshot
2975            .excerpts
2976            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2977        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2978
2979        let prefix = cursor.slice(&Some(locator), Bias::Left);
2980        new_excerpts.append(prefix, ());
2981
2982        let mut excerpt = cursor.item().unwrap().clone();
2983        let old_text_len = excerpt.text_summary.len;
2984
2985        excerpt.range.context.start = range.start;
2986        excerpt.range.context.end = range.end;
2987        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2988
2989        excerpt.text_summary = excerpt
2990            .buffer
2991            .text_summary_for_range(excerpt.range.context.clone());
2992
2993        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2994        let old_start_offset = cursor.start().1;
2995        let new_text_len = excerpt.text_summary.len;
2996        let edit = Edit {
2997            old: old_start_offset..old_start_offset + old_text_len,
2998            new: new_start_offset..new_start_offset + new_text_len,
2999        };
3000
3001        if let Some(last_edit) = edits.last_mut() {
3002            if last_edit.old.end == edit.old.start {
3003                last_edit.old.end = edit.old.end;
3004                last_edit.new.end = edit.new.end;
3005            } else {
3006                edits.push(edit);
3007            }
3008        } else {
3009            edits.push(edit);
3010        }
3011
3012        new_excerpts.push(excerpt, ());
3013
3014        cursor.next();
3015
3016        new_excerpts.append(cursor.suffix(), ());
3017
3018        drop(cursor);
3019        snapshot.excerpts = new_excerpts;
3020
3021        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3022        if !edits.is_empty() {
3023            self.subscriptions.publish(edits);
3024        }
3025        cx.emit(Event::Edited {
3026            edited_buffer: None,
3027            is_local: true,
3028        });
3029        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
3030        cx.notify();
3031    }
3032
3033    pub fn expand_excerpts(
3034        &mut self,
3035        ids: impl IntoIterator<Item = ExcerptId>,
3036        line_count: u32,
3037        direction: ExpandExcerptDirection,
3038        cx: &mut Context<Self>,
3039    ) {
3040        if line_count == 0 {
3041            return;
3042        }
3043        self.sync_mut(cx);
3044        if !self.excerpts_by_path.is_empty() {
3045            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
3046            return;
3047        }
3048        let mut snapshot = self.snapshot.get_mut();
3049
3050        let ids = ids.into_iter().collect::<Vec<_>>();
3051        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
3052        let mut new_excerpts = SumTree::default();
3053        let mut cursor = snapshot
3054            .excerpts
3055            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3056        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
3057
3058        for locator in &locators {
3059            let prefix = cursor.slice(&Some(locator), Bias::Left);
3060            new_excerpts.append(prefix, ());
3061
3062            let mut excerpt = cursor.item().unwrap().clone();
3063            let old_text_len = excerpt.text_summary.len;
3064
3065            let up_line_count = if direction.should_expand_up() {
3066                line_count
3067            } else {
3068                0
3069            };
3070
3071            let start_row = excerpt
3072                .range
3073                .context
3074                .start
3075                .to_point(&excerpt.buffer)
3076                .row
3077                .saturating_sub(up_line_count);
3078            let start_point = Point::new(start_row, 0);
3079            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3080
3081            let down_line_count = if direction.should_expand_down() {
3082                line_count
3083            } else {
3084                0
3085            };
3086
3087            let mut end_point = excerpt.buffer.clip_point(
3088                excerpt.range.context.end.to_point(&excerpt.buffer)
3089                    + Point::new(down_line_count, 0),
3090                Bias::Left,
3091            );
3092            end_point.column = excerpt.buffer.line_len(end_point.row);
3093            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3094            excerpt.max_buffer_row = end_point.row;
3095
3096            excerpt.text_summary = excerpt
3097                .buffer
3098                .text_summary_for_range(excerpt.range.context.clone());
3099
3100            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3101            let old_start_offset = cursor.start().1;
3102            let new_text_len = excerpt.text_summary.len;
3103            let edit = Edit {
3104                old: old_start_offset..old_start_offset + old_text_len,
3105                new: new_start_offset..new_start_offset + new_text_len,
3106            };
3107
3108            if let Some(last_edit) = edits.last_mut() {
3109                if last_edit.old.end == edit.old.start {
3110                    last_edit.old.end = edit.old.end;
3111                    last_edit.new.end = edit.new.end;
3112                } else {
3113                    edits.push(edit);
3114                }
3115            } else {
3116                edits.push(edit);
3117            }
3118
3119            new_excerpts.push(excerpt, ());
3120
3121            cursor.next();
3122        }
3123
3124        new_excerpts.append(cursor.suffix(), ());
3125
3126        drop(cursor);
3127        snapshot.excerpts = new_excerpts;
3128
3129        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3130        if !edits.is_empty() {
3131            self.subscriptions.publish(edits);
3132        }
3133        cx.emit(Event::Edited {
3134            edited_buffer: None,
3135            is_local: true,
3136        });
3137        cx.emit(Event::ExcerptsExpanded { ids });
3138        cx.notify();
3139    }
3140
3141    #[ztracing::instrument(skip_all)]
3142    fn sync(&self, cx: &App) {
3143        let changed = self.buffer_changed_since_sync.replace(false);
3144        if !changed {
3145            return;
3146        }
3147        let edits = Self::sync_from_buffer_changes(
3148            &mut self.snapshot.borrow_mut(),
3149            &self.buffers,
3150            &self.diffs,
3151            cx,
3152        );
3153        if !edits.is_empty() {
3154            self.subscriptions.publish(edits);
3155        }
3156    }
3157
3158    fn sync_mut(&mut self, cx: &App) {
3159        let changed = self.buffer_changed_since_sync.replace(false);
3160        if !changed {
3161            return;
3162        }
3163        let edits =
3164            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3165
3166        if !edits.is_empty() {
3167            self.subscriptions.publish(edits);
3168        }
3169    }
3170
3171    fn sync_from_buffer_changes(
3172        snapshot: &mut MultiBufferSnapshot,
3173        buffers: &BTreeMap<BufferId, BufferState>,
3174        diffs: &HashMap<BufferId, DiffState>,
3175        cx: &App,
3176    ) -> Vec<Edit<MultiBufferOffset>> {
3177        let MultiBufferSnapshot {
3178            excerpts,
3179            buffer_locators: _,
3180            diffs: buffer_diff,
3181            diff_transforms: _,
3182            non_text_state_update_count,
3183            edit_count,
3184            is_dirty,
3185            has_deleted_file,
3186            has_conflict,
3187            has_inverted_diff: _,
3188            singleton: _,
3189            excerpt_ids: _,
3190            replaced_excerpts: _,
3191            trailing_excerpt_update_count: _,
3192            all_diff_hunks_expanded: _,
3193            show_deleted_hunks: _,
3194            use_extended_diff_range: _,
3195            show_headers: _,
3196        } = snapshot;
3197        *is_dirty = false;
3198        *has_deleted_file = false;
3199        *has_conflict = false;
3200
3201        if !diffs.is_empty() {
3202            let mut diffs_to_add = Vec::new();
3203            for (id, diff) in diffs {
3204                if find_diff_state(buffer_diff, *id).is_none_or(|existing_diff| {
3205                    if existing_diff.main_buffer.is_none() {
3206                        return false;
3207                    }
3208                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3209                    base_text.remote_id() != existing_diff.base_text().remote_id()
3210                        || base_text
3211                            .version()
3212                            .changed_since(existing_diff.base_text().version())
3213                }) {
3214                    if diffs_to_add.capacity() == 0 {
3215                        diffs_to_add.reserve(diffs.len());
3216                    }
3217                    diffs_to_add.push(sum_tree::Edit::Insert(diff.snapshot(*id, cx)));
3218                }
3219            }
3220            buffer_diff.edit(diffs_to_add, ());
3221        }
3222
3223        let mut excerpts_to_edit = Vec::new();
3224        let mut non_text_state_updated = false;
3225        let mut edited = false;
3226        for buffer_state in buffers.values() {
3227            let buffer = buffer_state.buffer.read(cx);
3228            let version = buffer.version();
3229            let non_text_state_update_count = buffer.non_text_state_update_count();
3230
3231            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3232            let buffer_non_text_state_updated =
3233                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3234            if buffer_edited || buffer_non_text_state_updated {
3235                *buffer_state.last_version.borrow_mut() = version;
3236                buffer_state
3237                    .last_non_text_state_update_count
3238                    .set(non_text_state_update_count);
3239                excerpts_to_edit.extend(
3240                    buffer_state
3241                        .excerpts
3242                        .iter()
3243                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3244                );
3245            }
3246
3247            edited |= buffer_edited;
3248            non_text_state_updated |= buffer_non_text_state_updated;
3249            *is_dirty |= buffer.is_dirty();
3250            *has_deleted_file |= buffer
3251                .file()
3252                .is_some_and(|file| file.disk_state().is_deleted());
3253            *has_conflict |= buffer.has_conflict();
3254        }
3255        if edited {
3256            *edit_count += 1;
3257        }
3258        if non_text_state_updated {
3259            *non_text_state_update_count += 1;
3260        }
3261
3262        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3263
3264        let mut edits = Vec::new();
3265        let mut new_excerpts = SumTree::default();
3266        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3267
3268        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3269            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3270            let old_excerpt = cursor.item().unwrap();
3271            let buffer = buffer.read(cx);
3272            let buffer_id = buffer.remote_id();
3273            let mut new_excerpt;
3274            if buffer_edited {
3275                edits.extend(
3276                    buffer
3277                        .edits_since_in_range::<usize>(
3278                            old_excerpt.buffer.version(),
3279                            old_excerpt.range.context.clone(),
3280                        )
3281                        .map(|edit| {
3282                            let excerpt_old_start = cursor.start().1;
3283                            let excerpt_new_start =
3284                                ExcerptDimension(new_excerpts.summary().text.len);
3285                            let old_start = excerpt_old_start + edit.old.start;
3286                            let old_end = excerpt_old_start + edit.old.end;
3287                            let new_start = excerpt_new_start + edit.new.start;
3288                            let new_end = excerpt_new_start + edit.new.end;
3289                            Edit {
3290                                old: old_start..old_end,
3291                                new: new_start..new_end,
3292                            }
3293                        }),
3294                );
3295
3296                new_excerpt = Excerpt::new(
3297                    old_excerpt.id,
3298                    locator.clone(),
3299                    buffer_id,
3300                    Arc::new(buffer.snapshot()),
3301                    old_excerpt.range.clone(),
3302                    old_excerpt.has_trailing_newline,
3303                );
3304            } else {
3305                new_excerpt = old_excerpt.clone();
3306                new_excerpt.buffer = Arc::new(buffer.snapshot());
3307            }
3308
3309            new_excerpts.push(new_excerpt, ());
3310            cursor.next();
3311        }
3312        new_excerpts.append(cursor.suffix(), ());
3313
3314        drop(cursor);
3315        *excerpts = new_excerpts;
3316
3317        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3318    }
3319
3320    fn sync_diff_transforms(
3321        snapshot: &mut MultiBufferSnapshot,
3322        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3323        change_kind: DiffChangeKind,
3324    ) -> Vec<Edit<MultiBufferOffset>> {
3325        if excerpt_edits.is_empty() {
3326            return vec![];
3327        }
3328
3329        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3330        let mut old_diff_transforms = snapshot
3331            .diff_transforms
3332            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3333        let mut new_diff_transforms = SumTree::default();
3334        let mut old_expanded_hunks = HashSet::default();
3335        let mut output_edits = Vec::new();
3336        let mut output_delta = 0_isize;
3337        let mut at_transform_boundary = true;
3338        let mut end_of_current_insert = None;
3339
3340        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3341        while let Some(edit) = excerpt_edits.next() {
3342            excerpts.seek_forward(&edit.new.start, Bias::Right);
3343            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3344                excerpts.prev();
3345            }
3346
3347            // Keep any transforms that are before the edit.
3348            if at_transform_boundary {
3349                at_transform_boundary = false;
3350                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3351                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3352                if let Some(transform) = old_diff_transforms.item()
3353                    && old_diff_transforms.end().0 == edit.old.start
3354                    && old_diff_transforms.start().0 < edit.old.start
3355                {
3356                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3357                    old_diff_transforms.next();
3358                }
3359            }
3360
3361            // Compute the start of the edit in output coordinates.
3362            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3363            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3364            let edit_new_start =
3365                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3366
3367            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3368                &edit,
3369                &mut excerpts,
3370                &mut old_diff_transforms,
3371                &mut new_diff_transforms,
3372                &mut end_of_current_insert,
3373                &mut old_expanded_hunks,
3374                snapshot,
3375                change_kind,
3376            );
3377
3378            // Compute the end of the edit in output coordinates.
3379            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3380            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3381            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3382            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3383            let output_edit = Edit {
3384                old: edit_old_start..edit_old_end,
3385                new: edit_new_start..edit_new_end,
3386            };
3387
3388            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3389            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3390            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3391                output_edits.push(output_edit);
3392            }
3393
3394            // If this is the last edit that intersects the current diff transform,
3395            // then recreate the content up to the end of this transform, to prepare
3396            // for reusing additional slices of the old transforms.
3397            if excerpt_edits
3398                .peek()
3399                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3400            {
3401                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3402                    && match old_diff_transforms.item() {
3403                        Some(DiffTransform::BufferContent {
3404                            inserted_hunk_info: Some(hunk),
3405                            ..
3406                        }) => excerpts.item().is_some_and(|excerpt| {
3407                            if let Some(diff) = find_diff_state(&snapshot.diffs, excerpt.buffer_id)
3408                                && diff.main_buffer.is_some()
3409                            {
3410                                return true;
3411                            }
3412                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3413                        }),
3414                        _ => true,
3415                    };
3416
3417                let mut excerpt_offset = edit.new.end;
3418                if !keep_next_old_transform {
3419                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3420                    old_diff_transforms.next();
3421                }
3422
3423                old_expanded_hunks.clear();
3424                Self::push_buffer_content_transform(
3425                    snapshot,
3426                    &mut new_diff_transforms,
3427                    excerpt_offset,
3428                    end_of_current_insert,
3429                );
3430                at_transform_boundary = true;
3431            }
3432        }
3433
3434        // Keep any transforms that are after the last edit.
3435        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3436
3437        // Ensure there's always at least one buffer content transform.
3438        if new_diff_transforms.is_empty() {
3439            new_diff_transforms.push(
3440                DiffTransform::BufferContent {
3441                    summary: Default::default(),
3442                    inserted_hunk_info: None,
3443                },
3444                (),
3445            );
3446        }
3447
3448        drop(old_diff_transforms);
3449        drop(excerpts);
3450        snapshot.diff_transforms = new_diff_transforms;
3451        snapshot.edit_count += 1;
3452
3453        #[cfg(any(test, feature = "test-support"))]
3454        snapshot.check_invariants();
3455        output_edits
3456    }
3457
3458    fn recompute_diff_transforms_for_edit(
3459        edit: &Edit<ExcerptOffset>,
3460        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3461        old_diff_transforms: &mut Cursor<
3462            DiffTransform,
3463            Dimensions<ExcerptOffset, MultiBufferOffset>,
3464        >,
3465        new_diff_transforms: &mut SumTree<DiffTransform>,
3466        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3467        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3468        snapshot: &MultiBufferSnapshot,
3469        change_kind: DiffChangeKind,
3470    ) -> bool {
3471        log::trace!(
3472            "recomputing diff transform for edit {:?} => {:?}",
3473            edit.old.start..edit.old.end,
3474            edit.new.start..edit.new.end
3475        );
3476
3477        // Record which hunks were previously expanded.
3478        while let Some(item) = old_diff_transforms.item() {
3479            if let Some(hunk_info) = item.hunk_info() {
3480                log::trace!(
3481                    "previously expanded hunk at {:?}",
3482                    old_diff_transforms.start()
3483                );
3484                old_expanded_hunks.insert(hunk_info);
3485            }
3486            if old_diff_transforms.end().0 > edit.old.end {
3487                break;
3488            }
3489            old_diff_transforms.next();
3490        }
3491
3492        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3493        // For inverted diffs, hunks are always shown, so we can't skip this.
3494        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3495        if old_expanded_hunks.is_empty()
3496            && change_kind == DiffChangeKind::BufferEdited
3497            && !all_diff_hunks_expanded
3498            && !snapshot.has_inverted_diff
3499        {
3500            return false;
3501        }
3502
3503        // Visit each excerpt that intersects the edit.
3504        let mut did_expand_hunks = false;
3505        while let Some(excerpt) = excerpts.item() {
3506            // Recompute the expanded hunks in the portion of the excerpt that
3507            // intersects the edit.
3508            if let Some(diff) = find_diff_state(&snapshot.diffs, excerpt.buffer_id) {
3509                let buffer = &excerpt.buffer;
3510                let excerpt_start = *excerpts.start();
3511                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3512                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3513                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3514                let edit_buffer_start =
3515                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3516                let edit_buffer_end =
3517                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3518                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3519
3520                if let Some(main_buffer) = &diff.main_buffer {
3521                    for hunk in diff.hunks_intersecting_base_text_range(
3522                        edit_buffer_start..edit_buffer_end,
3523                        main_buffer,
3524                    ) {
3525                        did_expand_hunks = true;
3526                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3527                        if hunk_buffer_range.start < excerpt_buffer_start {
3528                            log::trace!("skipping hunk that starts before excerpt");
3529                            continue;
3530                        }
3531                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3532                        let hunk_excerpt_start = excerpt_start
3533                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3534                        let hunk_excerpt_end = excerpt_end
3535                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3536                        Self::push_buffer_content_transform(
3537                            snapshot,
3538                            new_diff_transforms,
3539                            hunk_excerpt_start,
3540                            *end_of_current_insert,
3541                        );
3542                        if !hunk_buffer_range.is_empty() {
3543                            let hunk_info = DiffTransformHunkInfo {
3544                                excerpt_id: excerpt.id,
3545                                hunk_start_anchor: hunk.buffer_range.start,
3546                                hunk_secondary_status: hunk.secondary_status,
3547                                is_logically_deleted: true,
3548                            };
3549                            *end_of_current_insert =
3550                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3551                        }
3552                    }
3553                } else {
3554                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3555                        ..buffer.anchor_after(edit_buffer_end);
3556                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3557                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3558                            continue;
3559                        }
3560
3561                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3562                        if hunk_buffer_range.start < excerpt_buffer_start {
3563                            log::trace!("skipping hunk that starts before excerpt");
3564                            continue;
3565                        }
3566
3567                        let hunk_info = DiffTransformHunkInfo {
3568                            excerpt_id: excerpt.id,
3569                            hunk_start_anchor: hunk.buffer_range.start,
3570                            hunk_secondary_status: hunk.secondary_status,
3571                            is_logically_deleted: false,
3572                        };
3573
3574                        let hunk_excerpt_start = excerpt_start
3575                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3576                        let hunk_excerpt_end = excerpt_end
3577                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3578
3579                        Self::push_buffer_content_transform(
3580                            snapshot,
3581                            new_diff_transforms,
3582                            hunk_excerpt_start,
3583                            *end_of_current_insert,
3584                        );
3585
3586                        // For every existing hunk, determine if it was previously expanded
3587                        // and if it should currently be expanded.
3588                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3589                        let should_expand_hunk = match &change_kind {
3590                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3591                                was_previously_expanded || all_diff_hunks_expanded
3592                            }
3593                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3594                                let intersects = hunk_buffer_range.is_empty()
3595                                    || hunk_buffer_range.end > edit_buffer_start;
3596                                if *expand {
3597                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3598                                } else {
3599                                    !intersects
3600                                        && (was_previously_expanded || all_diff_hunks_expanded)
3601                                }
3602                            }
3603                            _ => was_previously_expanded || all_diff_hunks_expanded,
3604                        };
3605
3606                        if should_expand_hunk {
3607                            did_expand_hunks = true;
3608                            log::trace!(
3609                                "expanding hunk {:?}, excerpt:{:?}",
3610                                hunk_excerpt_start..hunk_excerpt_end,
3611                                excerpt.id
3612                            );
3613
3614                            if !hunk.diff_base_byte_range.is_empty()
3615                                && hunk_buffer_range.start >= edit_buffer_start
3616                                && hunk_buffer_range.start <= excerpt_buffer_end
3617                                && snapshot.show_deleted_hunks
3618                            {
3619                                let base_text = diff.base_text();
3620                                let mut text_cursor =
3621                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3622                                let mut base_text_summary = text_cursor
3623                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3624
3625                                let mut has_trailing_newline = false;
3626                                if base_text_summary.last_line_chars > 0 {
3627                                    base_text_summary += TextSummary::newline();
3628                                    has_trailing_newline = true;
3629                                }
3630
3631                                new_diff_transforms.push(
3632                                    DiffTransform::DeletedHunk {
3633                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3634                                        summary: base_text_summary,
3635                                        buffer_id: excerpt.buffer_id,
3636                                        hunk_info,
3637                                        has_trailing_newline,
3638                                    },
3639                                    (),
3640                                );
3641                            }
3642
3643                            if !hunk_buffer_range.is_empty() {
3644                                *end_of_current_insert =
3645                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3646                            }
3647                        }
3648                    }
3649                }
3650            }
3651
3652            if excerpts.end() <= edit.new.end {
3653                excerpts.next();
3654            } else {
3655                break;
3656            }
3657        }
3658
3659        did_expand_hunks || !old_expanded_hunks.is_empty()
3660    }
3661
3662    fn append_diff_transforms(
3663        new_transforms: &mut SumTree<DiffTransform>,
3664        subtree: SumTree<DiffTransform>,
3665    ) {
3666        if let Some(DiffTransform::BufferContent {
3667            inserted_hunk_info,
3668            summary,
3669        }) = subtree.first()
3670            && Self::extend_last_buffer_content_transform(
3671                new_transforms,
3672                *inserted_hunk_info,
3673                *summary,
3674            )
3675        {
3676            let mut cursor = subtree.cursor::<()>(());
3677            cursor.next();
3678            cursor.next();
3679            new_transforms.append(cursor.suffix(), ());
3680            return;
3681        }
3682        new_transforms.append(subtree, ());
3683    }
3684
3685    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3686        if let DiffTransform::BufferContent {
3687            inserted_hunk_info: inserted_hunk_anchor,
3688            summary,
3689        } = transform
3690            && Self::extend_last_buffer_content_transform(
3691                new_transforms,
3692                inserted_hunk_anchor,
3693                summary,
3694            )
3695        {
3696            return;
3697        }
3698        new_transforms.push(transform, ());
3699    }
3700
3701    fn push_buffer_content_transform(
3702        old_snapshot: &MultiBufferSnapshot,
3703        new_transforms: &mut SumTree<DiffTransform>,
3704        end_offset: ExcerptOffset,
3705        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3706    ) {
3707        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3708            (end_offset.min(insertion_end_offset), Some(hunk_info))
3709        });
3710        let unchanged_region = [(end_offset, None)];
3711
3712        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3713        {
3714            let start_offset = new_transforms.summary().excerpt_len();
3715            if end_offset <= start_offset {
3716                continue;
3717            }
3718            let summary_to_add = old_snapshot
3719                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3720
3721            if !Self::extend_last_buffer_content_transform(
3722                new_transforms,
3723                inserted_hunk_info,
3724                summary_to_add,
3725            ) {
3726                new_transforms.push(
3727                    DiffTransform::BufferContent {
3728                        summary: summary_to_add,
3729                        inserted_hunk_info,
3730                    },
3731                    (),
3732                )
3733            }
3734        }
3735    }
3736
3737    fn extend_last_buffer_content_transform(
3738        new_transforms: &mut SumTree<DiffTransform>,
3739        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3740        summary_to_add: MBTextSummary,
3741    ) -> bool {
3742        let mut did_extend = false;
3743        new_transforms.update_last(
3744            |last_transform| {
3745                if let DiffTransform::BufferContent {
3746                    summary,
3747                    inserted_hunk_info: inserted_hunk_anchor,
3748                } = last_transform
3749                    && *inserted_hunk_anchor == new_inserted_hunk_info
3750                {
3751                    *summary += summary_to_add;
3752                    did_extend = true;
3753                }
3754            },
3755            (),
3756        );
3757        did_extend
3758    }
3759
3760    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3761        let snapshot = self.snapshot(cx);
3762        let excerpt_id = range.end.excerpt_id;
3763        let point_range = range.to_point(&snapshot);
3764        let expand = !self.single_hunk_is_expanded(range, cx);
3765        let edits =
3766            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3767        if !edits.is_empty() {
3768            self.subscriptions.publish(edits);
3769        }
3770        cx.emit(Event::DiffHunksToggled);
3771        cx.emit(Event::Edited {
3772            edited_buffer: None,
3773            is_local: true,
3774        });
3775    }
3776}
3777
3778fn build_excerpt_ranges(
3779    ranges: impl IntoIterator<Item = Range<Point>>,
3780    context_line_count: u32,
3781    buffer_snapshot: &BufferSnapshot,
3782) -> Vec<ExcerptRange<Point>> {
3783    ranges
3784        .into_iter()
3785        .map(|range| {
3786            let start_row = range.start.row.saturating_sub(context_line_count);
3787            let start = Point::new(start_row, 0);
3788            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3789            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3790            ExcerptRange {
3791                context: start..end,
3792                primary: range,
3793            }
3794        })
3795        .collect()
3796}
3797
3798#[cfg(any(test, feature = "test-support"))]
3799impl MultiBuffer {
3800    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3801        let buffer = cx.new(|cx| Buffer::local(text, cx));
3802        cx.new(|cx| Self::singleton(buffer, cx))
3803    }
3804
3805    pub fn build_multi<const COUNT: usize>(
3806        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3807        cx: &mut gpui::App,
3808    ) -> Entity<Self> {
3809        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3810        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3811            let buffer = cx.new(|cx| Buffer::local(text, cx));
3812            let snapshot = buffer.read(cx).snapshot();
3813            let excerpt_ranges = ranges
3814                .into_iter()
3815                .map(ExcerptRange::new)
3816                .collect::<Vec<_>>();
3817            multi.update(cx, |multi, cx| {
3818                multi.set_excerpt_ranges_for_path(
3819                    PathKey::sorted(ix as u64),
3820                    buffer,
3821                    &snapshot,
3822                    excerpt_ranges,
3823                    cx,
3824                )
3825            });
3826        }
3827
3828        multi
3829    }
3830
3831    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3832        cx.new(|cx| Self::singleton(buffer, cx))
3833    }
3834
3835    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3836        cx.new(|cx| {
3837            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3838            let mutation_count = rng.random_range(1..=5);
3839            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3840            multibuffer
3841        })
3842    }
3843
3844    pub fn randomly_edit(
3845        &mut self,
3846        rng: &mut impl rand::Rng,
3847        edit_count: usize,
3848        cx: &mut Context<Self>,
3849    ) {
3850        use util::RandomCharIter;
3851
3852        let snapshot = self.read(cx);
3853        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3854        let mut last_end = None;
3855        for _ in 0..edit_count {
3856            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3857                break;
3858            }
3859
3860            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3861            let end =
3862                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3863            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3864            last_end = Some(end);
3865
3866            let mut range = start..end;
3867            if rng.random_bool(0.2) {
3868                mem::swap(&mut range.start, &mut range.end);
3869            }
3870
3871            let new_text_len = rng.random_range(0..10);
3872            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3873
3874            edits.push((range, new_text.into()));
3875        }
3876        log::info!("mutating multi-buffer with {:?}", edits);
3877        drop(snapshot);
3878
3879        self.edit(edits, None, cx);
3880    }
3881
3882    pub fn randomly_edit_excerpts(
3883        &mut self,
3884        rng: &mut impl rand::Rng,
3885        mutation_count: usize,
3886        cx: &mut Context<Self>,
3887    ) {
3888        use rand::prelude::*;
3889        use std::env;
3890        use util::RandomCharIter;
3891
3892        let max_excerpts = env::var("MAX_EXCERPTS")
3893            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3894            .unwrap_or(5);
3895
3896        let mut buffers = Vec::new();
3897        for _ in 0..mutation_count {
3898            if rng.random_bool(0.05) {
3899                log::info!("Clearing multi-buffer");
3900                self.clear(cx);
3901                continue;
3902            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3903                let ids = self.excerpt_ids();
3904                let mut excerpts = HashSet::default();
3905                for _ in 0..rng.random_range(0..ids.len()) {
3906                    excerpts.extend(ids.choose(rng).copied());
3907                }
3908
3909                let line_count = rng.random_range(0..5);
3910
3911                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3912
3913                self.expand_excerpts(
3914                    excerpts.iter().cloned(),
3915                    line_count,
3916                    ExpandExcerptDirection::UpAndDown,
3917                    cx,
3918                );
3919                continue;
3920            }
3921
3922            let excerpt_ids = self.excerpt_ids();
3923            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3924                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3925                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3926                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3927                    let buffer = buffers.last().unwrap().read(cx);
3928                    log::info!(
3929                        "Creating new buffer {} with text: {:?}",
3930                        buffer.remote_id(),
3931                        buffer.text()
3932                    );
3933                    buffers.last().unwrap().clone()
3934                } else {
3935                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3936                };
3937
3938                let buffer = buffer_handle.read(cx);
3939                let buffer_text = buffer.text();
3940                let ranges = (0..rng.random_range(0..5))
3941                    .map(|_| {
3942                        let end_ix =
3943                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3944                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3945                        ExcerptRange::new(start_ix..end_ix)
3946                    })
3947                    .collect::<Vec<_>>();
3948                log::info!(
3949                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3950                    buffer_handle.read(cx).remote_id(),
3951                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3952                    ranges
3953                        .iter()
3954                        .map(|r| &buffer_text[r.context.clone()])
3955                        .collect::<Vec<_>>()
3956                );
3957
3958                let excerpt_id =
3959                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3960                log::info!("Inserted with ids: {:?}", excerpt_id);
3961            } else {
3962                let remove_count = rng.random_range(1..=excerpt_ids.len());
3963                let mut excerpts_to_remove = excerpt_ids
3964                    .choose_multiple(rng, remove_count)
3965                    .cloned()
3966                    .collect::<Vec<_>>();
3967                let snapshot = self.snapshot.borrow();
3968                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3969                drop(snapshot);
3970                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3971                self.remove_excerpts(excerpts_to_remove, cx);
3972            }
3973        }
3974    }
3975
3976    pub fn randomly_mutate(
3977        &mut self,
3978        rng: &mut impl rand::Rng,
3979        mutation_count: usize,
3980        cx: &mut Context<Self>,
3981    ) {
3982        use rand::prelude::*;
3983
3984        if rng.random_bool(0.7) || self.singleton {
3985            let buffer = self
3986                .buffers
3987                .values()
3988                .choose(rng)
3989                .map(|state| state.buffer.clone());
3990
3991            if let Some(buffer) = buffer {
3992                buffer.update(cx, |buffer, cx| {
3993                    if rng.random() {
3994                        buffer.randomly_edit(rng, mutation_count, cx);
3995                    } else {
3996                        buffer.randomly_undo_redo(rng, cx);
3997                    }
3998                });
3999            } else {
4000                self.randomly_edit(rng, mutation_count, cx);
4001            }
4002        } else {
4003            self.randomly_edit_excerpts(rng, mutation_count, cx);
4004        }
4005
4006        self.check_invariants(cx);
4007    }
4008
4009    fn check_invariants(&self, cx: &App) {
4010        self.read(cx).check_invariants();
4011    }
4012}
4013
4014impl EventEmitter<Event> for MultiBuffer {}
4015
4016impl MultiBufferSnapshot {
4017    pub fn text(&self) -> String {
4018        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
4019            .map(|chunk| chunk.text)
4020            .collect()
4021    }
4022
4023    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
4024        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
4025            .flat_map(|c| c.chars().rev())
4026    }
4027
4028    fn reversed_chunks_in_range(
4029        &self,
4030        range: Range<MultiBufferOffset>,
4031    ) -> ReversedMultiBufferChunks<'_> {
4032        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4033        cursor.seek(&range.end);
4034        let current_chunks = cursor.region().as_ref().map(|region| {
4035            let start_overshoot = range.start.saturating_sub(region.range.start);
4036            let end_overshoot = range.end - region.range.start;
4037            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
4038            let start = region.buffer_range.start + start_overshoot;
4039            region.buffer.reversed_chunks_in_range(start..end)
4040        });
4041        ReversedMultiBufferChunks {
4042            cursor,
4043            current_chunks,
4044            start: range.start,
4045            offset: range.end,
4046        }
4047    }
4048
4049    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
4050        let offset = position.to_offset(self);
4051        self.text_for_range(offset..self.len())
4052            .flat_map(|chunk| chunk.chars())
4053    }
4054
4055    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
4056        self.chunks(range, false).map(|chunk| chunk.text)
4057    }
4058
4059    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
4060        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
4061            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
4062    }
4063
4064    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
4065    where
4066        T: ToOffset,
4067    {
4068        let position = position.to_offset(self);
4069        position == self.clip_offset(position, Bias::Left)
4070            && self
4071                .bytes_in_range(position..self.len())
4072                .flatten()
4073                .copied()
4074                .take(needle.len())
4075                .eq(needle.bytes())
4076    }
4077
4078    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4079        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4080    }
4081
4082    pub fn diff_hunks_in_range<T: ToPoint>(
4083        &self,
4084        range: Range<T>,
4085    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4086        let query_range = range.start.to_point(self)..range.end.to_point(self);
4087        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4088            let diff = self.diff_state(buffer.remote_id())?;
4089            let iter = if let Some(main_buffer) = &diff.main_buffer {
4090                let buffer_start = buffer.point_to_offset(buffer_range.start);
4091                let buffer_end = buffer.point_to_offset(buffer_range.end);
4092                itertools::Either::Left(
4093                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4094                        .map(move |hunk| (hunk, buffer, true)),
4095                )
4096            } else {
4097                let buffer_start = buffer.anchor_before(buffer_range.start);
4098                let buffer_end = buffer.anchor_after(buffer_range.end);
4099                itertools::Either::Right(
4100                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4101                        .map(move |hunk| (hunk, buffer, false)),
4102                )
4103            };
4104            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4105                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4106                    return None;
4107                }
4108                let range = if is_inverted {
4109                    hunk.diff_base_byte_range.to_point(&buffer)
4110                } else {
4111                    hunk.range.clone()
4112                };
4113                Some((range, (hunk, is_inverted)))
4114            }))
4115        })
4116        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4117            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4118            {
4119                return None;
4120            }
4121            let end_row = if range.end.column == 0 {
4122                range.end.row
4123            } else {
4124                range.end.row + 1
4125            };
4126
4127            let word_diffs =
4128                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4129                    .then(|| {
4130                        let mut word_diffs = Vec::new();
4131
4132                        if self.show_deleted_hunks || is_inverted {
4133                            let hunk_start_offset = if is_inverted {
4134                                Anchor::in_buffer(
4135                                    excerpt.id,
4136                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4137                                )
4138                                .to_offset(self)
4139                            } else {
4140                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4141                                    .to_offset(self)
4142                            };
4143
4144                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4145                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4146                            }));
4147                        }
4148
4149                        if !is_inverted {
4150                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4151                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4152                            }));
4153                        }
4154                        word_diffs
4155                    })
4156                    .unwrap_or_default();
4157
4158            let buffer_range = if is_inverted {
4159                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4160                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4161            } else {
4162                hunk.buffer_range.clone()
4163            };
4164            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4165                DiffHunkStatusKind::Deleted
4166            } else if hunk.diff_base_byte_range.is_empty() {
4167                DiffHunkStatusKind::Added
4168            } else {
4169                DiffHunkStatusKind::Modified
4170            };
4171            Some(MultiBufferDiffHunk {
4172                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4173                buffer_id: excerpt.buffer_id,
4174                excerpt_id: excerpt.id,
4175                buffer_range,
4176                word_diffs,
4177                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4178                    ..BufferOffset(hunk.diff_base_byte_range.end),
4179                status: DiffHunkStatus {
4180                    kind: status_kind,
4181                    secondary: hunk.secondary_status,
4182                },
4183            })
4184        })
4185    }
4186
4187    fn excerpts_for_range<T: ToOffset>(
4188        &self,
4189        range: Range<T>,
4190    ) -> impl Iterator<Item = &Excerpt> + '_ {
4191        let range = range.start.to_offset(self)..range.end.to_offset(self);
4192        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4193        cursor.seek(&range.start);
4194        std::iter::from_fn(move || {
4195            let region = cursor.region()?;
4196            if region.range.start > range.end
4197                || region.range.start == range.end && region.range.start > range.start
4198            {
4199                return None;
4200            }
4201            let excerpt = region.excerpt;
4202            cursor.next_excerpt_forwards();
4203            Some(excerpt)
4204        })
4205    }
4206
4207    pub fn excerpt_ids_for_range<T: ToOffset>(
4208        &self,
4209        range: Range<T>,
4210    ) -> impl Iterator<Item = ExcerptId> + '_ {
4211        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4212    }
4213
4214    pub fn buffer_ids_for_range<T: ToOffset>(
4215        &self,
4216        range: Range<T>,
4217    ) -> impl Iterator<Item = BufferId> + '_ {
4218        self.excerpts_for_range(range)
4219            .map(|excerpt| excerpt.buffer_id)
4220    }
4221
4222    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4223    ///
4224    /// The passed in anchors must be ordered.
4225    pub fn text_anchors_to_visible_anchors(
4226        &self,
4227        anchors: impl IntoIterator<Item = text::Anchor>,
4228    ) -> Vec<Option<Anchor>> {
4229        let anchors = anchors.into_iter();
4230        let mut result = Vec::with_capacity(anchors.size_hint().0);
4231        let mut anchors = anchors.peekable();
4232        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4233        'anchors: while let Some(anchor) = anchors.peek() {
4234            let Some(buffer_id) = anchor.buffer_id else {
4235                anchors.next();
4236                result.push(None);
4237                continue 'anchors;
4238            };
4239            let mut same_buffer_anchors =
4240                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4241
4242            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4243                let Some(mut next) = same_buffer_anchors.next() else {
4244                    continue 'anchors;
4245                };
4246                'excerpts: for locator in locators.iter() {
4247                    if cursor.seek_forward(&Some(locator), Bias::Left)
4248                        && let Some(excerpt) = cursor.item()
4249                    {
4250                        loop {
4251                            // anchor is before the first excerpt
4252                            if excerpt
4253                                .range
4254                                .context
4255                                .start
4256                                .cmp(&next, &excerpt.buffer)
4257                                .is_gt()
4258                            {
4259                                // so we skip it and try the next anchor
4260                                result.push(None);
4261                                match same_buffer_anchors.next() {
4262                                    Some(anchor) => next = anchor,
4263                                    None => continue 'anchors,
4264                                }
4265                            // anchor is within the excerpt
4266                            } else if excerpt
4267                                .range
4268                                .context
4269                                .end
4270                                .cmp(&next, &excerpt.buffer)
4271                                .is_ge()
4272                            {
4273                                // record it and all following anchors that are within
4274                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4275                                result.extend(
4276                                    same_buffer_anchors
4277                                        .peeking_take_while(|a| {
4278                                            excerpt
4279                                                .range
4280                                                .context
4281                                                .end
4282                                                .cmp(a, &excerpt.buffer)
4283                                                .is_ge()
4284                                        })
4285                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4286                                );
4287                                match same_buffer_anchors.next() {
4288                                    Some(anchor) => next = anchor,
4289                                    None => continue 'anchors,
4290                                }
4291                            // anchor is after the excerpt, try the next one
4292                            } else {
4293                                continue 'excerpts;
4294                            }
4295                        }
4296                    }
4297                }
4298                // account for `next`
4299                result.push(None);
4300            }
4301            result.extend(same_buffer_anchors.map(|_| None));
4302        }
4303
4304        result
4305    }
4306
4307    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4308        &self,
4309        ranges: impl Iterator<Item = Range<T>>,
4310    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4311        ranges.flat_map(|range| {
4312            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4313                .into_iter()
4314        })
4315    }
4316
4317    pub fn range_to_buffer_ranges<R, T>(
4318        &self,
4319        range: R,
4320    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4321    where
4322        R: RangeBounds<T>,
4323        T: ToOffset,
4324    {
4325        self.range_to_buffer_ranges_with_context(range)
4326            .into_iter()
4327            .map(|(buffer, range, id, _context)| (buffer, range, id))
4328            .collect()
4329    }
4330
4331    pub fn range_to_buffer_ranges_with_context<R, T>(
4332        &self,
4333        range: R,
4334    ) -> Vec<(
4335        &BufferSnapshot,
4336        Range<BufferOffset>,
4337        ExcerptId,
4338        Range<text::Anchor>,
4339    )>
4340    where
4341        R: RangeBounds<T>,
4342        T: ToOffset,
4343    {
4344        let start = match range.start_bound() {
4345            Bound::Included(start) => start.to_offset(self),
4346            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4347            Bound::Unbounded => MultiBufferOffset::ZERO,
4348        };
4349        let end_bound = match range.end_bound() {
4350            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4351            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4352            Bound::Unbounded => Bound::Unbounded,
4353        };
4354        let bounds = (Bound::Included(start), end_bound);
4355
4356        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4357        cursor.seek(&start);
4358
4359        let mut result: Vec<(
4360            &BufferSnapshot,
4361            Range<BufferOffset>,
4362            ExcerptId,
4363            Range<text::Anchor>,
4364        )> = Vec::new();
4365        while let Some(region) = cursor.region() {
4366            let dominated_by_end_bound = match end_bound {
4367                Bound::Included(end) => region.range.start > end,
4368                Bound::Excluded(end) => region.range.start >= end,
4369                Bound::Unbounded => false,
4370            };
4371            if dominated_by_end_bound {
4372                break;
4373            }
4374            if region.is_main_buffer {
4375                let start_overshoot = start.saturating_sub(region.range.start);
4376                let end_offset = match end_bound {
4377                    Bound::Included(end) | Bound::Excluded(end) => end,
4378                    Bound::Unbounded => region.range.end,
4379                };
4380                let end_overshoot = end_offset.saturating_sub(region.range.start);
4381                let start = region
4382                    .buffer_range
4383                    .end
4384                    .min(region.buffer_range.start + start_overshoot);
4385                let end = region
4386                    .buffer_range
4387                    .end
4388                    .min(region.buffer_range.start + end_overshoot);
4389                let context = region.excerpt.range.context.clone();
4390                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4391                    *excerpt_id == region.excerpt.id && prev_range.end == start
4392                }) {
4393                    prev.1.end = end;
4394                } else {
4395                    result.push((region.buffer, start..end, region.excerpt.id, context));
4396                }
4397            }
4398            cursor.next();
4399        }
4400
4401        if let Some(excerpt) = cursor.excerpt() {
4402            let dominated_by_prev_excerpt =
4403                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4404            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4405                let excerpt_position = self.len();
4406                if bounds.contains(&excerpt_position) {
4407                    let buffer_offset =
4408                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4409                    let context = excerpt.range.context.clone();
4410                    result.push((
4411                        &excerpt.buffer,
4412                        buffer_offset..buffer_offset,
4413                        excerpt.id,
4414                        context,
4415                    ));
4416                }
4417            }
4418        }
4419
4420        result
4421    }
4422
4423    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4424        &self,
4425        range: Range<T>,
4426    ) -> impl Iterator<
4427        Item = (
4428            &BufferSnapshot,
4429            Range<BufferOffset>,
4430            ExcerptId,
4431            Option<Anchor>,
4432        ),
4433    > + '_ {
4434        let start = range.start.to_offset(self);
4435        let end = range.end.to_offset(self);
4436
4437        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4438        cursor.seek(&start);
4439
4440        std::iter::from_fn(move || {
4441            let region = cursor.region()?;
4442            if region.range.start > end {
4443                return None;
4444            }
4445            let start_overshoot = start.saturating_sub(region.range.start);
4446            let end_overshoot = end.saturating_sub(region.range.start);
4447            let start = region
4448                .buffer_range
4449                .end
4450                .min(region.buffer_range.start + start_overshoot);
4451            let end = region
4452                .buffer_range
4453                .end
4454                .min(region.buffer_range.start + end_overshoot);
4455
4456            let region_excerpt_id = region.excerpt.id;
4457            let deleted_hunk_anchor = if region.is_main_buffer {
4458                None
4459            } else {
4460                Some(self.anchor_before(region.range.start))
4461            };
4462            let result = (
4463                region.buffer,
4464                start..end,
4465                region_excerpt_id,
4466                deleted_hunk_anchor,
4467            );
4468            cursor.next();
4469            Some(result)
4470        })
4471    }
4472
4473    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4474    /// coordinates.
4475    ///
4476    /// The given callback will be called for every excerpt intersecting the given range. It will
4477    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4478    /// The callback should return an iterator of metadata items from that buffer, each paired
4479    /// with a buffer range.
4480    ///
4481    /// The returned iterator yields each of these metadata items, paired with its range in
4482    /// multi-buffer coordinates.
4483    fn lift_buffer_metadata<'a, MBD, M, I>(
4484        &'a self,
4485        query_range: Range<MBD>,
4486        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4487    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4488    where
4489        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4490        MBD: MultiBufferDimension
4491            + Ord
4492            + Sub<Output = MBD::TextDimension>
4493            + ops::Add<MBD::TextDimension, Output = MBD>
4494            + ops::AddAssign<MBD::TextDimension>,
4495        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4496            + ops::Add<Output = MBD::TextDimension>
4497            + AddAssign<MBD::TextDimension>
4498            + Ord,
4499    {
4500        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4501        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4502
4503        // Find the excerpt and buffer offset where the given range ends.
4504        cursor.seek(&query_range.end);
4505        let mut range_end = None;
4506        while let Some(region) = cursor.region() {
4507            if region.is_main_buffer {
4508                let mut buffer_end = region.buffer_range.start;
4509                let overshoot = if query_range.end > region.range.start {
4510                    query_range.end - region.range.start
4511                } else {
4512                    <MBD::TextDimension>::default()
4513                };
4514                buffer_end = buffer_end + overshoot;
4515                range_end = Some((region.excerpt.id, buffer_end));
4516                break;
4517            }
4518            cursor.next();
4519        }
4520
4521        cursor.seek(&query_range.start);
4522
4523        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4524            && region.range.start > MBD::default()
4525        {
4526            cursor.prev()
4527        } else if let Some(region) = cursor.region()
4528            && region.is_main_buffer
4529            && region.diff_hunk_status.is_some()
4530        {
4531            cursor.prev();
4532            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4533                cursor.next();
4534            }
4535        }
4536
4537        iter::from_fn(move || {
4538            loop {
4539                let excerpt = cursor.excerpt()?;
4540
4541                // If we have already retrieved metadata for this excerpt, continue to use it.
4542                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4543                    .as_mut()
4544                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4545                {
4546                    Some(metadata)
4547                }
4548                // Otherwise, compute the intersection of the input range with the excerpt's range,
4549                // and retrieve the metadata for the resulting range.
4550                else {
4551                    let region = cursor.region()?;
4552                    let mut buffer_start;
4553                    if region.is_main_buffer {
4554                        buffer_start = region.buffer_range.start;
4555                        if query_range.start > region.range.start {
4556                            let overshoot = query_range.start - region.range.start;
4557                            buffer_start = buffer_start + overshoot;
4558                        }
4559                        buffer_start = buffer_start.min(region.buffer_range.end);
4560                    } else {
4561                        buffer_start = cursor.main_buffer_position()?;
4562                    };
4563                    let mut buffer_end = excerpt
4564                        .range
4565                        .context
4566                        .end
4567                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4568                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4569                        && excerpt.id == end_excerpt_id
4570                    {
4571                        buffer_end = buffer_end.min(end_buffer_offset);
4572                    }
4573
4574                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4575                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4576                    })
4577                };
4578
4579                // Visit each metadata item.
4580                if let Some((metadata_buffer_range, metadata)) =
4581                    metadata_iter.and_then(Iterator::next)
4582                {
4583                    // Find the multibuffer regions that contain the start and end of
4584                    // the metadata item's range.
4585                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4586                        while let Some(region) = cursor.region() {
4587                            if (region.is_main_buffer
4588                                && (region.buffer_range.end >= metadata_buffer_range.start
4589                                    || cursor.is_at_end_of_excerpt()))
4590                                || (!region.is_main_buffer
4591                                    && region.buffer_range.start == metadata_buffer_range.start)
4592                            {
4593                                break;
4594                            }
4595                            cursor.next();
4596                        }
4597                    }
4598                    let start_region = cursor.region()?.clone();
4599                    while let Some(region) = cursor.region() {
4600                        if region.is_main_buffer
4601                            && (region.buffer_range.end > metadata_buffer_range.end
4602                                || cursor.is_at_end_of_excerpt())
4603                        {
4604                            break;
4605                        }
4606                        cursor.next();
4607                    }
4608                    let end_region = cursor.region();
4609
4610                    // Convert the metadata item's range into multibuffer coordinates.
4611                    let mut start_position = start_region.range.start;
4612                    let region_buffer_start = start_region.buffer_range.start;
4613                    if start_region.is_main_buffer
4614                        && metadata_buffer_range.start > region_buffer_start
4615                    {
4616                        start_position =
4617                            start_position + (metadata_buffer_range.start - region_buffer_start);
4618                        start_position = start_position.min(start_region.range.end);
4619                    }
4620
4621                    let mut end_position = self.max_position();
4622                    if let Some(end_region) = &end_region {
4623                        end_position = end_region.range.start;
4624                        debug_assert!(end_region.is_main_buffer);
4625                        let region_buffer_start = end_region.buffer_range.start;
4626                        if metadata_buffer_range.end > region_buffer_start {
4627                            end_position =
4628                                end_position + (metadata_buffer_range.end - region_buffer_start);
4629                        }
4630                        end_position = end_position.min(end_region.range.end);
4631                    }
4632
4633                    if start_position <= query_range.end && end_position >= query_range.start {
4634                        return Some((start_position..end_position, metadata, excerpt));
4635                    }
4636                }
4637                // When there are no more metadata items for this excerpt, move to the next excerpt.
4638                else {
4639                    current_excerpt_metadata.take();
4640                    if let Some((end_excerpt_id, _)) = range_end
4641                        && excerpt.id == end_excerpt_id
4642                    {
4643                        return None;
4644                    }
4645                    cursor.next_excerpt_forwards();
4646                }
4647            }
4648        })
4649    }
4650
4651    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4652        let offset = position.to_offset(self);
4653
4654        let mut cursor = self
4655            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4656            );
4657        cursor.seek(&DimensionPair {
4658            key: offset,
4659            value: None,
4660        });
4661        cursor.seek_to_start_of_current_excerpt();
4662        let excerpt = cursor.excerpt()?;
4663
4664        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4665        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4666        let current_position = self
4667            .anchor_before(offset)
4668            .text_anchor
4669            .to_offset(&excerpt.buffer);
4670
4671        if let Some(diff) = self.diff_state(excerpt.buffer_id) {
4672            if let Some(main_buffer) = &diff.main_buffer {
4673                for hunk in diff
4674                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4675                {
4676                    if hunk.diff_base_byte_range.end >= current_position {
4677                        continue;
4678                    }
4679                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4680                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4681                    return Some(MultiBufferRow(start.row));
4682                }
4683            } else {
4684                let excerpt_end = excerpt
4685                    .buffer
4686                    .anchor_before(excerpt_end.min(current_position));
4687                for hunk in diff.hunks_intersecting_range_rev(
4688                    excerpt.range.context.start..excerpt_end,
4689                    &excerpt.buffer,
4690                ) {
4691                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4692                    if hunk_end >= current_position {
4693                        continue;
4694                    }
4695                    let start =
4696                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4697                    return Some(MultiBufferRow(start.row));
4698                }
4699            }
4700        }
4701
4702        loop {
4703            cursor.prev_excerpt();
4704            let excerpt = cursor.excerpt()?;
4705
4706            let Some(diff) = self.diff_state(excerpt.buffer_id) else {
4707                continue;
4708            };
4709            if let Some(main_buffer) = &diff.main_buffer {
4710                let Some(hunk) = diff
4711                    .hunks_intersecting_base_text_range_rev(
4712                        excerpt.range.context.to_offset(&excerpt.buffer),
4713                        main_buffer,
4714                    )
4715                    .next()
4716                else {
4717                    continue;
4718                };
4719                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4720                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4721                return Some(MultiBufferRow(start.row));
4722            } else {
4723                let Some(hunk) = diff
4724                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4725                    .next()
4726                else {
4727                    continue;
4728                };
4729                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4730                return Some(MultiBufferRow(start.row));
4731            }
4732        }
4733    }
4734
4735    pub fn has_diff_hunks(&self) -> bool {
4736        self.diffs.iter().any(|diff| !diff.is_empty())
4737    }
4738
4739    pub fn is_inside_word<T: ToOffset>(
4740        &self,
4741        position: T,
4742        scope_context: Option<CharScopeContext>,
4743    ) -> bool {
4744        let position = position.to_offset(self);
4745        let classifier = self
4746            .char_classifier_at(position)
4747            .scope_context(scope_context);
4748        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4749        let prev_char_kind = self
4750            .reversed_chars_at(position)
4751            .next()
4752            .map(|c| classifier.kind(c));
4753        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4754    }
4755
4756    pub fn surrounding_word<T: ToOffset>(
4757        &self,
4758        start: T,
4759        scope_context: Option<CharScopeContext>,
4760    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4761        let mut start = start.to_offset(self);
4762        let mut end = start;
4763        let mut next_chars = self.chars_at(start).peekable();
4764        let mut prev_chars = self.reversed_chars_at(start).peekable();
4765
4766        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4767
4768        let word_kind = cmp::max(
4769            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4770            next_chars.peek().copied().map(|c| classifier.kind(c)),
4771        );
4772
4773        for ch in prev_chars {
4774            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4775                start -= ch.len_utf8();
4776            } else {
4777                break;
4778            }
4779        }
4780
4781        for ch in next_chars {
4782            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4783                end += ch.len_utf8();
4784            } else {
4785                break;
4786            }
4787        }
4788
4789        (start..end, word_kind)
4790    }
4791
4792    pub fn char_kind_before<T: ToOffset>(
4793        &self,
4794        start: T,
4795        scope_context: Option<CharScopeContext>,
4796    ) -> Option<CharKind> {
4797        let start = start.to_offset(self);
4798        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4799        self.reversed_chars_at(start)
4800            .next()
4801            .map(|ch| classifier.kind(ch))
4802    }
4803
4804    pub fn is_singleton(&self) -> bool {
4805        self.singleton
4806    }
4807
4808    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4809        if self.singleton {
4810            self.excerpts
4811                .iter()
4812                .next()
4813                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4814        } else {
4815            None
4816        }
4817    }
4818
4819    pub fn len(&self) -> MultiBufferOffset {
4820        self.diff_transforms.summary().output.len
4821    }
4822
4823    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4824        MBD::from_summary(&self.text_summary())
4825    }
4826
4827    pub fn is_empty(&self) -> bool {
4828        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4829    }
4830
4831    pub fn widest_line_number(&self) -> u32 {
4832        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4833        self.excerpts.summary().widest_line_number + 1
4834    }
4835
4836    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4837        let range = range.start.to_offset(self)..range.end.to_offset(self);
4838        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4839        excerpts.seek(&range.start);
4840
4841        let mut chunk;
4842        let mut has_trailing_newline;
4843        let excerpt_bytes;
4844        if let Some(region) = excerpts.region() {
4845            let mut bytes = region.buffer.bytes_in_range(
4846                region.buffer_range.start + (range.start - region.range.start)
4847                    ..(region.buffer_range.start + (range.end - region.range.start))
4848                        .min(region.buffer_range.end),
4849            );
4850            chunk = bytes.next().unwrap_or(&[][..]);
4851            excerpt_bytes = Some(bytes);
4852            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4853            if chunk.is_empty() && has_trailing_newline {
4854                chunk = b"\n";
4855                has_trailing_newline = false;
4856            }
4857        } else {
4858            chunk = &[][..];
4859            excerpt_bytes = None;
4860            has_trailing_newline = false;
4861        };
4862
4863        MultiBufferBytes {
4864            range,
4865            cursor: excerpts,
4866            excerpt_bytes,
4867            has_trailing_newline,
4868            chunk,
4869        }
4870    }
4871
4872    pub fn reversed_bytes_in_range<T: ToOffset>(
4873        &self,
4874        range: Range<T>,
4875    ) -> ReversedMultiBufferBytes<'_> {
4876        let range = range.start.to_offset(self)..range.end.to_offset(self);
4877        let mut chunks = self.reversed_chunks_in_range(range.clone());
4878        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4879        ReversedMultiBufferBytes {
4880            range,
4881            chunks,
4882            chunk,
4883        }
4884    }
4885
4886    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4887        let mut cursor = self.cursor::<Point, Point>();
4888        cursor.seek(&Point::new(start_row.0, 0));
4889        let mut result = MultiBufferRows {
4890            point: Point::new(0, 0),
4891            is_empty: self.excerpts.is_empty(),
4892            is_singleton: self.is_singleton(),
4893            cursor,
4894        };
4895        result.seek(start_row);
4896        result
4897    }
4898
4899    pub fn chunks<T: ToOffset>(
4900        &self,
4901        range: Range<T>,
4902        language_aware: bool,
4903    ) -> MultiBufferChunks<'_> {
4904        let mut chunks = MultiBufferChunks {
4905            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4906                ..ExcerptDimension(MultiBufferOffset::ZERO),
4907            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4908            excerpts: self.excerpts.cursor(()),
4909            diff_transforms: self.diff_transforms.cursor(()),
4910            diffs: &self.diffs,
4911            diff_base_chunks: None,
4912            excerpt_chunks: None,
4913            buffer_chunk: None,
4914            language_aware,
4915        };
4916        let range = range.start.to_offset(self)..range.end.to_offset(self);
4917        chunks.seek(range);
4918        chunks
4919    }
4920
4921    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4922        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4923    }
4924
4925    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4926        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4927    }
4928
4929    pub fn clip_offset_utf16(
4930        &self,
4931        offset: MultiBufferOffsetUtf16,
4932        bias: Bias,
4933    ) -> MultiBufferOffsetUtf16 {
4934        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4935    }
4936
4937    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4938        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4939            buffer.clip_point_utf16(Unclipped(point), bias)
4940        })
4941    }
4942
4943    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4944        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4945    }
4946
4947    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4948        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4949    }
4950
4951    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4952        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4953    }
4954
4955    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4956        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4957    }
4958
4959    #[instrument(skip_all)]
4960    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4961        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4962    }
4963
4964    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4965        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4966    }
4967
4968    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4969        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4970    }
4971
4972    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4973        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4974    }
4975
4976    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4977        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4978    }
4979
4980    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4981        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4982    }
4983
4984    fn clip_dimension<MBD, BD>(
4985        &self,
4986        position: MBD,
4987        bias: Bias,
4988        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4989    ) -> MBD
4990    where
4991        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4992        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4993    {
4994        let mut cursor = self.cursor::<MBD, BD>();
4995        cursor.seek(&position);
4996        if let Some(region) = cursor.region() {
4997            if position >= region.range.end {
4998                return region.range.end;
4999            }
5000            let overshoot = position - region.range.start;
5001            let mut buffer_position = region.buffer_range.start;
5002            buffer_position += overshoot;
5003            let clipped_buffer_position =
5004                clip_buffer_position(region.buffer, buffer_position, bias);
5005            let mut position = region.range.start;
5006            position += clipped_buffer_position - region.buffer_range.start;
5007            position
5008        } else {
5009            self.max_position()
5010        }
5011    }
5012
5013    #[instrument(skip_all)]
5014    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
5015        &self,
5016        key: MBR1,
5017        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
5018    ) -> MBR2
5019    where
5020        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
5021        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
5022        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
5023        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
5024    {
5025        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
5026        cursor.seek(&DimensionPair { key, value: None });
5027        if let Some(region) = cursor.region() {
5028            if key >= region.range.end.key {
5029                return region.range.end.value.unwrap();
5030            }
5031            let start_key = region.range.start.key;
5032            let start_value = region.range.start.value.unwrap();
5033            let buffer_start_key = region.buffer_range.start.key;
5034            let buffer_start_value = region.buffer_range.start.value.unwrap();
5035            let mut buffer_key = buffer_start_key;
5036            buffer_key += key - start_key;
5037            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
5038            let mut result = start_value;
5039            result += buffer_value - buffer_start_value;
5040            result
5041        } else {
5042            self.max_position()
5043        }
5044    }
5045
5046    pub fn point_to_buffer_offset<T: ToOffset>(
5047        &self,
5048        point: T,
5049    ) -> Option<(&BufferSnapshot, BufferOffset)> {
5050        let offset = point.to_offset(self);
5051        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
5052        cursor.seek(&offset);
5053        let region = cursor.region()?;
5054        let overshoot = offset - region.range.start;
5055        let buffer_offset = region.buffer_range.start + overshoot;
5056        if buffer_offset == BufferOffset(region.buffer.len() + 1)
5057            && region.has_trailing_newline
5058            && !region.is_main_buffer
5059        {
5060            let main_buffer_position = cursor.main_buffer_position()?;
5061            let buffer_snapshot = &cursor.excerpt()?.buffer;
5062            return Some((buffer_snapshot, main_buffer_position));
5063        } else if buffer_offset > BufferOffset(region.buffer.len()) {
5064            return None;
5065        }
5066        Some((region.buffer, buffer_offset))
5067    }
5068
5069    pub fn point_to_buffer_point(
5070        &self,
5071        point: Point,
5072    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5073        let mut cursor = self.cursor::<Point, Point>();
5074        cursor.seek(&point);
5075        let region = cursor.region()?;
5076        let overshoot = point - region.range.start;
5077        let buffer_point = region.buffer_range.start + overshoot;
5078        let excerpt = cursor.excerpt()?;
5079        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5080            && region.has_trailing_newline
5081            && !region.is_main_buffer
5082        {
5083            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5084        } else if buffer_point > region.buffer.max_point() {
5085            return None;
5086        }
5087        Some((region.buffer, buffer_point, excerpt.id))
5088    }
5089
5090    pub fn suggested_indents(
5091        &self,
5092        rows: impl IntoIterator<Item = u32>,
5093        cx: &App,
5094    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5095        let mut result = BTreeMap::new();
5096        self.suggested_indents_callback(
5097            rows,
5098            &mut |row, indent| {
5099                result.insert(row, indent);
5100                ControlFlow::Continue(())
5101            },
5102            cx,
5103        );
5104        result
5105    }
5106
5107    // move this to be a generator once those are a thing
5108    pub fn suggested_indents_callback(
5109        &self,
5110        rows: impl IntoIterator<Item = u32>,
5111        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5112        cx: &App,
5113    ) {
5114        let mut rows_for_excerpt = Vec::new();
5115        let mut cursor = self.cursor::<Point, Point>();
5116        let mut rows = rows.into_iter().peekable();
5117        let mut prev_row = u32::MAX;
5118        let mut prev_language_indent_size = IndentSize::default();
5119
5120        while let Some(row) = rows.next() {
5121            cursor.seek(&Point::new(row, 0));
5122            let Some(region) = cursor.region() else {
5123                continue;
5124            };
5125
5126            // Retrieve the language and indent size once for each disjoint region being indented.
5127            let single_indent_size = if row.saturating_sub(1) == prev_row {
5128                prev_language_indent_size
5129            } else {
5130                region
5131                    .buffer
5132                    .language_indent_size_at(Point::new(row, 0), cx)
5133            };
5134            prev_language_indent_size = single_indent_size;
5135            prev_row = row;
5136
5137            let start_buffer_row = region.buffer_range.start.row;
5138            let start_multibuffer_row = region.range.start.row;
5139            let end_multibuffer_row = region.range.end.row;
5140
5141            rows_for_excerpt.push(row);
5142            while let Some(next_row) = rows.peek().copied() {
5143                if end_multibuffer_row > next_row {
5144                    rows_for_excerpt.push(next_row);
5145                    rows.next();
5146                } else {
5147                    break;
5148                }
5149            }
5150
5151            let buffer_rows = rows_for_excerpt
5152                .drain(..)
5153                .map(|row| start_buffer_row + row - start_multibuffer_row);
5154            let buffer_indents = region
5155                .buffer
5156                .suggested_indents(buffer_rows, single_indent_size);
5157            for (row, indent) in buffer_indents {
5158                if cb(
5159                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5160                    indent,
5161                )
5162                .is_break()
5163                {
5164                    return;
5165                }
5166            }
5167        }
5168    }
5169
5170    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5171        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5172            let mut size = buffer.indent_size_for_line(range.start.row);
5173            size.len = size
5174                .len
5175                .min(range.end.column)
5176                .saturating_sub(range.start.column);
5177            size
5178        } else {
5179            IndentSize::spaces(0)
5180        }
5181    }
5182
5183    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5184        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5185            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5186        } else {
5187            LineIndent::spaces(0)
5188        }
5189    }
5190
5191    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5192        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5193
5194        if self.language_settings(cx).extend_comment_on_newline
5195            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5196        {
5197            let delimiters = language_scope.line_comment_prefixes();
5198            for delimiter in delimiters {
5199                if *self
5200                    .chars_at(Point::new(row.0, indent.len() as u32))
5201                    .take(delimiter.chars().count())
5202                    .collect::<String>()
5203                    .as_str()
5204                    == **delimiter
5205                {
5206                    indent.push_str(delimiter);
5207                    break;
5208                }
5209            }
5210        }
5211
5212        indent
5213    }
5214
5215    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5216    where
5217        T: ToOffset,
5218    {
5219        for char in self.reversed_chars_at(position) {
5220            if !char.is_whitespace() {
5221                return false;
5222            }
5223            if char == '\n' {
5224                return true;
5225            }
5226        }
5227        true
5228    }
5229
5230    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5231        while row.0 > 0 {
5232            row.0 -= 1;
5233            if !self.is_line_blank(row) {
5234                return Some(row);
5235            }
5236        }
5237        None
5238    }
5239
5240    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5241        if let Some((_, range)) = self.buffer_line_for_row(row) {
5242            range.end.column - range.start.column
5243        } else {
5244            0
5245        }
5246    }
5247
5248    pub fn line_len_utf16(&self, row: MultiBufferRow) -> u32 {
5249        self.clip_point_utf16(Unclipped(PointUtf16::new(row.0, u32::MAX)), Bias::Left)
5250            .column
5251    }
5252
5253    pub fn buffer_line_for_row(
5254        &self,
5255        row: MultiBufferRow,
5256    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5257        let mut cursor = self.cursor::<Point, Point>();
5258        let point = Point::new(row.0, 0);
5259        cursor.seek(&point);
5260        let region = cursor.region()?;
5261        let overshoot = point.min(region.range.end) - region.range.start;
5262        let buffer_point = region.buffer_range.start + overshoot;
5263        if buffer_point.row > region.buffer_range.end.row {
5264            return None;
5265        }
5266        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5267        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5268            .min(region.buffer_range.end);
5269        Some((region.buffer, line_start..line_end))
5270    }
5271
5272    pub fn max_point(&self) -> Point {
5273        self.text_summary().lines
5274    }
5275
5276    pub fn max_row(&self) -> MultiBufferRow {
5277        MultiBufferRow(self.text_summary().lines.row)
5278    }
5279
5280    pub fn text_summary(&self) -> MBTextSummary {
5281        self.diff_transforms.summary().output
5282    }
5283
5284    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5285    where
5286        MBD: MultiBufferDimension + AddAssign,
5287        O: ToOffset,
5288    {
5289        let range = range.start.to_offset(self)..range.end.to_offset(self);
5290        let mut cursor = self
5291            .diff_transforms
5292            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5293        cursor.seek(&range.start, Bias::Right);
5294
5295        let Some(first_transform) = cursor.item() else {
5296            return MBD::from_summary(&MBTextSummary::default());
5297        };
5298
5299        let diff_transform_start = cursor.start().0;
5300        let diff_transform_end = cursor.end().0;
5301        let diff_start = range.start;
5302        let start_overshoot = diff_start - diff_transform_start;
5303        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5304
5305        let mut result = match first_transform {
5306            DiffTransform::BufferContent { .. } => {
5307                let excerpt_start = cursor.start().1 + start_overshoot;
5308                let excerpt_end = cursor.start().1 + end_overshoot;
5309                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5310            }
5311            DiffTransform::DeletedHunk {
5312                buffer_id,
5313                base_text_byte_range,
5314                has_trailing_newline,
5315                ..
5316            } => {
5317                let buffer_start = base_text_byte_range.start + start_overshoot;
5318                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5319                let Some(base_text) = self.diff_state(*buffer_id).map(|diff| diff.base_text())
5320                else {
5321                    panic!("{:?} is in non-existent deleted hunk", range.start)
5322                };
5323
5324                let include_trailing_newline =
5325                    *has_trailing_newline && range.end >= diff_transform_end;
5326                if include_trailing_newline {
5327                    buffer_end -= 1;
5328                }
5329
5330                let mut summary = base_text
5331                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5332
5333                if include_trailing_newline {
5334                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5335                        &TextSummary::newline(),
5336                    ))
5337                }
5338
5339                let mut result = MBD::default();
5340                result.add_text_dim(&summary);
5341                result
5342            }
5343        };
5344        if range.end < diff_transform_end {
5345            return result;
5346        }
5347
5348        cursor.next();
5349        result.add_mb_text_summary(
5350            &cursor
5351                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5352                .0,
5353        );
5354
5355        let Some(last_transform) = cursor.item() else {
5356            return result;
5357        };
5358
5359        let overshoot = range.end - cursor.start().0;
5360        let suffix = match last_transform {
5361            DiffTransform::BufferContent { .. } => {
5362                let end = cursor.start().1 + overshoot;
5363                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5364            }
5365            DiffTransform::DeletedHunk {
5366                base_text_byte_range,
5367                buffer_id,
5368                has_trailing_newline,
5369                ..
5370            } => {
5371                let buffer_end = base_text_byte_range.start + overshoot;
5372                let Some(base_text) = self.diff_state(*buffer_id).map(|diff| diff.base_text())
5373                else {
5374                    panic!("{:?} is in non-existent deleted hunk", range.end)
5375                };
5376
5377                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5378                    base_text_byte_range.start..buffer_end,
5379                );
5380                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5381                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5382                        &TextSummary::from("\n"),
5383                    ))
5384                }
5385
5386                let mut result = MBD::default();
5387                result.add_text_dim(&suffix);
5388                result
5389            }
5390        };
5391
5392        result += suffix;
5393        result
5394    }
5395
5396    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5397    where
5398        MBD: MultiBufferDimension + AddAssign,
5399    {
5400        let mut summary = MBD::default();
5401        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5402        cursor.seek(&range.start, Bias::Right);
5403        if let Some(excerpt) = cursor.item() {
5404            let mut end_before_newline = cursor.end();
5405            if excerpt.has_trailing_newline {
5406                end_before_newline -= 1;
5407            }
5408
5409            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5410            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5411            let end_in_excerpt =
5412                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5413            summary.add_text_dim(
5414                &excerpt
5415                    .buffer
5416                    .text_summary_for_range::<MBD::TextDimension, _>(
5417                        start_in_excerpt..end_in_excerpt,
5418                    ),
5419            );
5420
5421            if range.end > end_before_newline {
5422                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5423            }
5424
5425            cursor.next();
5426        }
5427
5428        if range.end > *cursor.start() {
5429            summary += cursor
5430                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5431                .0;
5432            if let Some(excerpt) = cursor.item() {
5433                range.end = cmp::max(*cursor.start(), range.end);
5434
5435                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5436                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5437                summary.add_text_dim(
5438                    &excerpt
5439                        .buffer
5440                        .text_summary_for_range::<MBD::TextDimension, _>(
5441                            excerpt_start..end_in_excerpt,
5442                        ),
5443                );
5444            }
5445        }
5446
5447        summary
5448    }
5449
5450    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5451    where
5452        MBD: MultiBufferDimension
5453            + Ord
5454            + Sub<Output = MBD::TextDimension>
5455            + Sub<MBD::TextDimension, Output = MBD>
5456            + AddAssign<MBD::TextDimension>
5457            + Add<MBD::TextDimension, Output = MBD>,
5458        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5459    {
5460        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5461        let locator = self.excerpt_locator_for_id(excerpt_id);
5462        let (start, _, mut item) = self
5463            .excerpts
5464            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5465        let mut start = MBD::from_summary(&start.text);
5466        if item.is_none() && excerpt_id == ExcerptId::max() {
5467            item = self.excerpts.last();
5468            if let Some(last_summary) = self.excerpts.last_summary() {
5469                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5470            }
5471        }
5472
5473        let excerpt_start_position = ExcerptDimension(start);
5474        if self.diff_transforms.is_empty() {
5475            if let Some(excerpt) = item {
5476                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5477                    return excerpt_start_position.0;
5478                }
5479                let excerpt_buffer_start = excerpt
5480                    .range
5481                    .context
5482                    .start
5483                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5484                let excerpt_buffer_end = excerpt
5485                    .range
5486                    .context
5487                    .end
5488                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5489                let buffer_summary = anchor
5490                    .text_anchor
5491                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5492                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5493                let mut position = excerpt_start_position;
5494                if summary > excerpt_buffer_start {
5495                    position += summary - excerpt_buffer_start;
5496                }
5497
5498                position.0
5499            } else {
5500                excerpt_start_position.0
5501            }
5502        } else {
5503            let mut diff_transforms_cursor = self
5504                .diff_transforms
5505                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5506            diff_transforms_cursor.next();
5507
5508            if let Some(excerpt) = item {
5509                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5510                    return self.resolve_summary_for_min_or_max_anchor(
5511                        &Anchor::min(),
5512                        excerpt_start_position,
5513                        &mut diff_transforms_cursor,
5514                    );
5515                }
5516                let excerpt_buffer_start = excerpt
5517                    .range
5518                    .context
5519                    .start
5520                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5521                let excerpt_buffer_end = excerpt
5522                    .range
5523                    .context
5524                    .end
5525                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5526                let buffer_summary = anchor
5527                    .text_anchor
5528                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5529                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5530                let mut position = excerpt_start_position;
5531                if summary > excerpt_buffer_start {
5532                    position += summary - excerpt_buffer_start;
5533                }
5534
5535                if diff_transforms_cursor.start().0 < position {
5536                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5537                }
5538                self.resolve_summary_for_anchor(
5539                    &anchor,
5540                    position,
5541                    &mut diff_transforms_cursor,
5542                    &excerpt.buffer,
5543                )
5544            } else {
5545                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5546                self.resolve_summary_for_min_or_max_anchor(
5547                    &Anchor::max(),
5548                    excerpt_start_position,
5549                    &mut diff_transforms_cursor,
5550                )
5551            }
5552        }
5553    }
5554
5555    /// Maps an anchor's excerpt-space position to its output-space position by
5556    /// walking the diff transforms. The cursor is shared across consecutive
5557    /// calls, so it may already be partway through the transform list.
5558    fn resolve_summary_for_anchor<MBD>(
5559        &self,
5560        anchor: &Anchor,
5561        excerpt_position: ExcerptDimension<MBD>,
5562        diff_transforms: &mut Cursor<
5563            DiffTransform,
5564            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5565        >,
5566        excerpt_buffer: &text::BufferSnapshot,
5567    ) -> MBD
5568    where
5569        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5570    {
5571        loop {
5572            let transform_end_position = diff_transforms.end().0;
5573            let item = diff_transforms.item();
5574            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5575
5576            // A right-biased anchor at a transform boundary belongs to the
5577            // *next* transform, so advance past the current one.
5578            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5579                diff_transforms.next();
5580                continue;
5581            }
5582
5583            let mut position = diff_transforms.start().1;
5584            match item {
5585                Some(DiffTransform::DeletedHunk {
5586                    buffer_id,
5587                    base_text_byte_range,
5588                    hunk_info,
5589                    ..
5590                }) => {
5591                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5592                        && let Some(base_text) =
5593                            self.diff_state(*buffer_id).map(|diff| diff.base_text())
5594                        && diff_base_anchor.is_valid(&base_text)
5595                    {
5596                        // The anchor carries a diff-base position — resolve it
5597                        // to a location inside the deleted hunk.
5598                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5599                        if base_text_offset >= base_text_byte_range.start
5600                            && base_text_offset <= base_text_byte_range.end
5601                        {
5602                            let position_in_hunk = base_text
5603                                .text_summary_for_range::<MBD::TextDimension, _>(
5604                                    base_text_byte_range.start..base_text_offset,
5605                                );
5606                            position.0.add_text_dim(&position_in_hunk);
5607                        } else if at_transform_end {
5608                            // diff_base offset falls outside this hunk's range;
5609                            // advance to see if the next transform is a better fit.
5610                            diff_transforms.next();
5611                            continue;
5612                        }
5613                    } else if at_transform_end
5614                        && anchor
5615                            .text_anchor
5616                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5617                            .is_gt()
5618                    {
5619                        // The anchor has no (valid) diff-base position, so it
5620                        // belongs in the buffer content, not in the deleted
5621                        // hunk. However, after an edit deletes the text between
5622                        // the hunk boundary and this anchor, both resolve to
5623                        // the same excerpt_position—landing us here on the
5624                        // DeletedHunk left behind by the shared cursor. Use the
5625                        // CRDT ordering to detect that the anchor is strictly
5626                        // *past* the hunk boundary and skip to the following
5627                        // BufferContent.
5628                        diff_transforms.next();
5629                        continue;
5630                    }
5631                }
5632                _ => {
5633                    // On a BufferContent (or no transform). If the anchor
5634                    // carries a diff_base_anchor it needs a DeletedHunk, so
5635                    // advance to find one.
5636                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5637                        diff_transforms.next();
5638                        continue;
5639                    }
5640                    let overshoot = excerpt_position - diff_transforms.start().0;
5641                    position += overshoot;
5642                }
5643            }
5644
5645            return position.0;
5646        }
5647    }
5648
5649    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5650    fn resolve_summary_for_min_or_max_anchor<MBD>(
5651        &self,
5652        anchor: &Anchor,
5653        excerpt_position: ExcerptDimension<MBD>,
5654        diff_transforms: &mut Cursor<
5655            DiffTransform,
5656            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5657        >,
5658    ) -> MBD
5659    where
5660        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5661    {
5662        loop {
5663            let transform_end_position = diff_transforms.end().0;
5664            let item = diff_transforms.item();
5665            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5666
5667            // A right-biased anchor at a transform boundary belongs to the
5668            // *next* transform, so advance past the current one.
5669            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5670                diff_transforms.next();
5671                continue;
5672            }
5673
5674            let mut position = diff_transforms.start().1;
5675            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5676                let overshoot = excerpt_position - diff_transforms.start().0;
5677                position += overshoot;
5678            }
5679
5680            return position.0;
5681        }
5682    }
5683
5684    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5685        let mut cursor = self
5686            .excerpts
5687            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5688        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5689
5690        cursor.seek(&Some(locator), Bias::Left);
5691        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5692            cursor.prev();
5693        }
5694
5695        let mut position = cursor.start().1;
5696        if let Some(excerpt) = cursor.item()
5697            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5698        {
5699            let excerpt_buffer_start = excerpt
5700                .buffer
5701                .offset_for_anchor(&excerpt.range.context.start);
5702            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5703            let buffer_position = cmp::min(
5704                excerpt_buffer_end,
5705                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5706            );
5707            if buffer_position > excerpt_buffer_start {
5708                position += buffer_position - excerpt_buffer_start;
5709            }
5710        }
5711        position
5712    }
5713
5714    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5715        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5716            excerpt_id = *replacement;
5717        }
5718        excerpt_id
5719    }
5720
5721    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5722    where
5723        MBD: MultiBufferDimension
5724            + Ord
5725            + Sub<Output = MBD::TextDimension>
5726            + AddAssign<MBD::TextDimension>,
5727        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5728        I: 'a + IntoIterator<Item = &'a Anchor>,
5729    {
5730        let mut anchors = anchors.into_iter().peekable();
5731        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5732        let mut diff_transforms_cursor = self
5733            .diff_transforms
5734            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5735        diff_transforms_cursor.next();
5736
5737        let mut summaries = Vec::new();
5738        while let Some(anchor) = anchors.peek() {
5739            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5740
5741            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5742                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5743            });
5744
5745            let locator = self.excerpt_locator_for_id(excerpt_id);
5746            cursor.seek_forward(locator, Bias::Left);
5747            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5748                cursor.prev();
5749            }
5750
5751            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5752            if let Some(excerpt) = cursor.item() {
5753                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5754                    let position = self.resolve_summary_for_min_or_max_anchor(
5755                        &Anchor::min(),
5756                        excerpt_start_position,
5757                        &mut diff_transforms_cursor,
5758                    );
5759                    summaries.extend(excerpt_anchors.map(|_| position));
5760                    continue;
5761                }
5762                let excerpt_buffer_start = excerpt
5763                    .range
5764                    .context
5765                    .start
5766                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5767                let excerpt_buffer_end = excerpt
5768                    .range
5769                    .context
5770                    .end
5771                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5772                for (buffer_summary, anchor) in excerpt
5773                    .buffer
5774                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5775                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5776                    )
5777                {
5778                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5779                    let mut position = excerpt_start_position;
5780                    if summary > excerpt_buffer_start {
5781                        position += summary - excerpt_buffer_start;
5782                    }
5783
5784                    if diff_transforms_cursor.start().0 < position {
5785                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5786                    }
5787
5788                    summaries.push(self.resolve_summary_for_anchor(
5789                        anchor,
5790                        position,
5791                        &mut diff_transforms_cursor,
5792                        &excerpt.buffer,
5793                    ));
5794                }
5795            } else {
5796                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5797                let position = self.resolve_summary_for_min_or_max_anchor(
5798                    &Anchor::max(),
5799                    excerpt_start_position,
5800                    &mut diff_transforms_cursor,
5801                );
5802                summaries.extend(excerpt_anchors.map(|_| position));
5803            }
5804        }
5805
5806        summaries
5807    }
5808
5809    pub fn dimensions_from_points<'a, MBD>(
5810        &'a self,
5811        points: impl 'a + IntoIterator<Item = Point>,
5812    ) -> impl 'a + Iterator<Item = MBD>
5813    where
5814        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5815    {
5816        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5817        cursor.seek(&DimensionPair {
5818            key: Point::default(),
5819            value: None,
5820        });
5821        let mut points = points.into_iter();
5822        iter::from_fn(move || {
5823            let point = points.next()?;
5824
5825            cursor.seek_forward(&DimensionPair {
5826                key: point,
5827                value: None,
5828            });
5829
5830            if let Some(region) = cursor.region() {
5831                let overshoot = point - region.range.start.key;
5832                let buffer_point = region.buffer_range.start + overshoot;
5833                let mut position = region.range.start.value.unwrap();
5834                position.add_text_dim(
5835                    &region
5836                        .buffer
5837                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5838                );
5839                if point == region.range.end.key && region.has_trailing_newline {
5840                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5841                }
5842                Some(position)
5843            } else {
5844                Some(MBD::from_summary(&self.text_summary()))
5845            }
5846        })
5847    }
5848
5849    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5850    where
5851        I: 'a + IntoIterator<Item = &'a Anchor>,
5852    {
5853        let mut anchors = anchors.into_iter().enumerate().peekable();
5854        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5855        cursor.next();
5856
5857        let mut result = Vec::new();
5858
5859        while let Some((_, anchor)) = anchors.peek() {
5860            let old_excerpt_id = anchor.excerpt_id;
5861
5862            // Find the location where this anchor's excerpt should be.
5863            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5864            cursor.seek_forward(&Some(old_locator), Bias::Left);
5865
5866            let next_excerpt = cursor.item();
5867            let prev_excerpt = cursor.prev_item();
5868
5869            // Process all of the anchors for this excerpt.
5870            while let Some((anchor_ix, &anchor)) =
5871                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5872            {
5873                let mut anchor = anchor;
5874
5875                // Leave min and max anchors unchanged if invalid or
5876                // if the old excerpt still exists at this location
5877                let mut kept_position = next_excerpt
5878                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5879                    || old_excerpt_id == ExcerptId::max()
5880                    || old_excerpt_id == ExcerptId::min();
5881
5882                // If the old excerpt no longer exists at this location, then attempt to
5883                // find an equivalent position for this anchor in an adjacent excerpt.
5884                if !kept_position {
5885                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5886                        if excerpt.contains(&anchor) {
5887                            anchor.excerpt_id = excerpt.id;
5888                            kept_position = true;
5889                            break;
5890                        }
5891                    }
5892                }
5893
5894                // If there's no adjacent excerpt that contains the anchor's position,
5895                // then report that the anchor has lost its position.
5896                if !kept_position {
5897                    anchor = if let Some(excerpt) = next_excerpt {
5898                        let mut text_anchor = excerpt
5899                            .range
5900                            .context
5901                            .start
5902                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5903                        if text_anchor
5904                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5905                            .is_gt()
5906                        {
5907                            text_anchor = excerpt.range.context.end;
5908                        }
5909                        Anchor::in_buffer(excerpt.id, text_anchor)
5910                    } else if let Some(excerpt) = prev_excerpt {
5911                        let mut text_anchor = excerpt
5912                            .range
5913                            .context
5914                            .end
5915                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5916                        if text_anchor
5917                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5918                            .is_lt()
5919                        {
5920                            text_anchor = excerpt.range.context.start;
5921                        }
5922                        Anchor::in_buffer(excerpt.id, text_anchor)
5923                    } else if anchor.text_anchor.bias == Bias::Left {
5924                        Anchor::min()
5925                    } else {
5926                        Anchor::max()
5927                    };
5928                }
5929
5930                result.push((anchor_ix, anchor, kept_position));
5931            }
5932        }
5933        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5934        result
5935    }
5936
5937    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5938        self.anchor_at(position, Bias::Left)
5939    }
5940
5941    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5942        self.anchor_at(position, Bias::Right)
5943    }
5944
5945    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5946        let offset = position.to_offset(self);
5947
5948        // Find the given position in the diff transforms. Determine the corresponding
5949        // offset in the excerpts, and whether the position is within a deleted hunk.
5950        let mut diff_transforms = self
5951            .diff_transforms
5952            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5953        diff_transforms.seek(&offset, Bias::Right);
5954
5955        if offset == diff_transforms.start().0
5956            && bias == Bias::Left
5957            && let Some(prev_item) = diff_transforms.prev_item()
5958            && let DiffTransform::DeletedHunk { .. } = prev_item
5959        {
5960            diff_transforms.prev();
5961        }
5962        let offset_in_transform = offset - diff_transforms.start().0;
5963        let mut excerpt_offset = diff_transforms.start().1;
5964        let mut diff_base_anchor = None;
5965        if let Some(DiffTransform::DeletedHunk {
5966            buffer_id,
5967            base_text_byte_range,
5968            has_trailing_newline,
5969            ..
5970        }) = diff_transforms.item()
5971        {
5972            let diff = self.diff_state(*buffer_id).expect("missing diff");
5973            if offset_in_transform > base_text_byte_range.len() {
5974                debug_assert!(*has_trailing_newline);
5975                bias = Bias::Right;
5976            } else {
5977                diff_base_anchor = Some(
5978                    diff.base_text()
5979                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5980                );
5981                bias = Bias::Left;
5982            }
5983        } else {
5984            excerpt_offset += MultiBufferOffset(offset_in_transform);
5985        };
5986
5987        let mut excerpts = self
5988            .excerpts
5989            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5990        excerpts.seek(&excerpt_offset, Bias::Right);
5991        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5992            excerpts.prev();
5993        }
5994        if let Some(excerpt) = excerpts.item() {
5995            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5996            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5997                overshoot -= 1;
5998                bias = Bias::Right;
5999            }
6000
6001            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
6002            let text_anchor =
6003                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
6004            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
6005            match diff_base_anchor {
6006                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
6007                None => anchor,
6008            }
6009        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
6010        {
6011            Anchor::min()
6012        } else {
6013            Anchor::max()
6014        }
6015    }
6016
6017    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
6018    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
6019        let (excerpt, buffer, _) = self.as_singleton()?;
6020        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
6021            Some(Anchor::in_buffer(excerpt, text_anchor))
6022        } else {
6023            None
6024        }
6025    }
6026
6027    /// Returns an anchor for the given excerpt and text anchor,
6028    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
6029    pub fn anchor_range_in_excerpt(
6030        &self,
6031        excerpt_id: ExcerptId,
6032        text_anchor: Range<text::Anchor>,
6033    ) -> Option<Range<Anchor>> {
6034        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
6035
6036        Some(
6037            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
6038                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
6039        )
6040    }
6041
6042    /// Returns an anchor for the given excerpt and text anchor,
6043    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
6044    pub fn anchor_in_excerpt(
6045        &self,
6046        excerpt_id: ExcerptId,
6047        text_anchor: text::Anchor,
6048    ) -> Option<Anchor> {
6049        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
6050        Self::anchor_in_excerpt_(excerpt, text_anchor)
6051    }
6052
6053    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
6054    pub fn anchors_in_excerpt(
6055        &self,
6056        excerpt_id: ExcerptId,
6057        text_anchors: impl IntoIterator<Item = text::Anchor>,
6058    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
6059        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
6060        Some(
6061            text_anchors
6062                .into_iter()
6063                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
6064        )
6065    }
6066
6067    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
6068        match text_anchor.buffer_id {
6069            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
6070            Some(_) => return None,
6071            None if text_anchor.is_max() || text_anchor.is_min() => {
6072                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
6073            }
6074            None => return None,
6075        }
6076
6077        let context = &excerpt.range.context;
6078        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6079            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6080        {
6081            return None;
6082        }
6083
6084        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6085    }
6086
6087    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6088        Some(self.excerpt(excerpt_id)?.range.context.clone())
6089    }
6090
6091    pub fn excerpt_range_for_excerpt(
6092        &self,
6093        excerpt_id: ExcerptId,
6094    ) -> Option<ExcerptRange<text::Anchor>> {
6095        Some(self.excerpt(excerpt_id)?.range.clone())
6096    }
6097
6098    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6099        if anchor.is_min() || anchor.is_max() {
6100            // todo(lw): should be `!self.is_empty()`
6101            true
6102        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6103            excerpt.buffer.can_resolve(&anchor.text_anchor)
6104        } else {
6105            false
6106        }
6107    }
6108
6109    pub fn excerpts(
6110        &self,
6111    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6112        self.excerpts
6113            .iter()
6114            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6115    }
6116
6117    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6118    where
6119        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6120        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6121    {
6122        let excerpts = self.excerpts.cursor(());
6123        let diff_transforms = self.diff_transforms.cursor(());
6124        MultiBufferCursor {
6125            excerpts,
6126            diff_transforms,
6127            diffs: &self.diffs,
6128            cached_region: OnceCell::new(),
6129        }
6130    }
6131
6132    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6133        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6134        let mut excerpts = self
6135            .excerpts
6136            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6137        excerpts.seek(&Some(start_locator), Bias::Left);
6138        excerpts.prev();
6139
6140        let mut diff_transforms = self
6141            .diff_transforms
6142            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6143        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6144        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6145            diff_transforms.next();
6146        }
6147
6148        let excerpt = excerpts.item()?;
6149        Some(MultiBufferExcerpt {
6150            excerpt,
6151            offset: diff_transforms.start().output_dimension.0,
6152            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6153            excerpt_offset: excerpts.start().1,
6154            diff_transforms,
6155        })
6156    }
6157
6158    pub fn excerpt_boundaries_in_range<R, T>(
6159        &self,
6160        range: R,
6161    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6162    where
6163        R: RangeBounds<T>,
6164        T: ToOffset,
6165    {
6166        let start_offset;
6167        let start = match range.start_bound() {
6168            Bound::Included(start) => {
6169                start_offset = start.to_offset(self);
6170                Bound::Included(start_offset)
6171            }
6172            Bound::Excluded(_) => {
6173                panic!("not supported")
6174            }
6175            Bound::Unbounded => {
6176                start_offset = MultiBufferOffset::ZERO;
6177                Bound::Unbounded
6178            }
6179        };
6180        let end = match range.end_bound() {
6181            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6182            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6183            Bound::Unbounded => Bound::Unbounded,
6184        };
6185        let bounds = (start, end);
6186        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6187        cursor.seek(&DimensionPair {
6188            key: start_offset,
6189            value: None,
6190        });
6191
6192        if cursor
6193            .fetch_excerpt_with_range()
6194            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6195        {
6196            cursor.prev_excerpt();
6197        } else {
6198            cursor.seek_to_start_of_current_excerpt();
6199        }
6200        let mut prev_region = cursor
6201            .fetch_excerpt_with_range()
6202            .map(|(excerpt, _)| excerpt);
6203
6204        cursor.next_excerpt_forwards();
6205
6206        iter::from_fn(move || {
6207            loop {
6208                if self.singleton {
6209                    return None;
6210                }
6211
6212                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6213                cursor.next_excerpt_forwards();
6214                if !bounds.contains(&next_range.start.key) {
6215                    prev_region = Some(next_excerpt);
6216                    continue;
6217                }
6218
6219                let next_region_start = next_range.start.value.unwrap();
6220                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6221                    range.start.value.unwrap()
6222                } else {
6223                    self.max_point()
6224                };
6225
6226                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6227                    id: region.id,
6228                    buffer: region.buffer.clone(),
6229                    buffer_id: region.buffer_id,
6230                    range: region.range.clone(),
6231                    end_row: MultiBufferRow(next_region_start.row),
6232                });
6233
6234                let next = ExcerptInfo {
6235                    id: next_excerpt.id,
6236                    buffer: next_excerpt.buffer.clone(),
6237                    buffer_id: next_excerpt.buffer_id,
6238                    range: next_excerpt.range.clone(),
6239                    end_row: if next_excerpt.has_trailing_newline {
6240                        MultiBufferRow(next_region_end.row - 1)
6241                    } else {
6242                        MultiBufferRow(next_region_end.row)
6243                    },
6244                };
6245
6246                let row = MultiBufferRow(next_region_start.row);
6247
6248                prev_region = Some(next_excerpt);
6249
6250                return Some(ExcerptBoundary { row, prev, next });
6251            }
6252        })
6253    }
6254
6255    pub fn edit_count(&self) -> usize {
6256        self.edit_count
6257    }
6258
6259    pub fn non_text_state_update_count(&self) -> usize {
6260        self.non_text_state_update_count
6261    }
6262
6263    /// Returns the smallest enclosing bracket ranges containing the given range or
6264    /// None if no brackets contain range or the range is not contained in a single
6265    /// excerpt
6266    ///
6267    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6268    #[ztracing::instrument(skip_all)]
6269    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6270        &self,
6271        range: Range<T>,
6272        range_filter: Option<
6273            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6274        >,
6275    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6276        let range = range.start.to_offset(self)..range.end.to_offset(self);
6277        let mut excerpt = self.excerpt_containing(range.clone())?;
6278        let buffer = excerpt.buffer();
6279        let excerpt_buffer_range = excerpt.buffer_range();
6280
6281        // Filter to ranges contained in the excerpt
6282        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6283            excerpt_buffer_range.contains(&BufferOffset(open.start))
6284                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6285                && range_filter.is_none_or(|filter| {
6286                    filter(
6287                        buffer,
6288                        BufferOffset(open.start)..BufferOffset(close.end),
6289                        BufferOffset(close.start)..BufferOffset(close.end),
6290                    )
6291                })
6292        };
6293
6294        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6295            excerpt.map_range_to_buffer(range),
6296            Some(&range_filter),
6297        )?;
6298
6299        Some((
6300            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6301            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6302        ))
6303    }
6304
6305    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6306    /// not contained in a single excerpt
6307    pub fn enclosing_bracket_ranges<T: ToOffset>(
6308        &self,
6309        range: Range<T>,
6310    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6311    {
6312        let range = range.start.to_offset(self)..range.end.to_offset(self);
6313        let mut excerpt = self.excerpt_containing(range.clone())?;
6314
6315        Some(
6316            excerpt
6317                .buffer()
6318                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6319                .filter_map(move |pair| {
6320                    let open_range =
6321                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6322                    let close_range =
6323                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6324                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6325                        Some((
6326                            excerpt.map_range_from_buffer(open_range),
6327                            excerpt.map_range_from_buffer(close_range),
6328                        ))
6329                    } else {
6330                        None
6331                    }
6332                }),
6333        )
6334    }
6335
6336    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6337    /// not contained in a single excerpt
6338    pub fn text_object_ranges<T: ToOffset>(
6339        &self,
6340        range: Range<T>,
6341        options: TreeSitterOptions,
6342    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6343        let range = range.start.to_offset(self)..range.end.to_offset(self);
6344        self.excerpt_containing(range.clone())
6345            .map(|mut excerpt| {
6346                excerpt
6347                    .buffer()
6348                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6349                    .filter_map(move |(range, text_object)| {
6350                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6351                        if excerpt.contains_buffer_range(range.clone()) {
6352                            Some((excerpt.map_range_from_buffer(range), text_object))
6353                        } else {
6354                            None
6355                        }
6356                    })
6357            })
6358            .into_iter()
6359            .flatten()
6360    }
6361
6362    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6363    /// not contained in a single excerpt
6364    pub fn bracket_ranges<T: ToOffset>(
6365        &self,
6366        range: Range<T>,
6367    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6368    {
6369        let range = range.start.to_offset(self)..range.end.to_offset(self);
6370        let mut excerpt = self.excerpt_containing(range.clone())?;
6371        Some(
6372            excerpt
6373                .buffer()
6374                .bracket_ranges(excerpt.map_range_to_buffer(range))
6375                .filter_map(move |pair| {
6376                    let open_range =
6377                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6378                    let close_range =
6379                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6380                    excerpt
6381                        .contains_buffer_range(open_range.start..close_range.end)
6382                        .then(|| BracketMatch {
6383                            open_range: excerpt.map_range_from_buffer(open_range),
6384                            close_range: excerpt.map_range_from_buffer(close_range),
6385                            color_index: pair.color_index,
6386                            newline_only: pair.newline_only,
6387                            syntax_layer_depth: pair.syntax_layer_depth,
6388                        })
6389                })
6390                .map(BracketMatch::bracket_ranges),
6391        )
6392    }
6393
6394    pub fn redacted_ranges<'a, T: ToOffset>(
6395        &'a self,
6396        range: Range<T>,
6397        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6398    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6399        let range = range.start.to_offset(self)..range.end.to_offset(self);
6400        self.lift_buffer_metadata(range, move |buffer, range| {
6401            if redaction_enabled(buffer.file()) {
6402                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6403            } else {
6404                None
6405            }
6406        })
6407        .map(|(range, _, _)| range)
6408    }
6409
6410    pub fn runnable_ranges(
6411        &self,
6412        range: Range<Anchor>,
6413    ) -> impl Iterator<Item = (Range<Anchor>, language::RunnableRange)> + '_ {
6414        let range = range.start.to_offset(self)..range.end.to_offset(self);
6415        self.lift_buffer_metadata(range, move |buffer, range| {
6416            Some(
6417                buffer
6418                    .runnable_ranges(range.clone())
6419                    .filter(move |runnable| {
6420                        runnable.run_range.start >= range.start
6421                            && runnable.run_range.end < range.end
6422                    })
6423                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6424            )
6425        })
6426        .map(|(run_range, runnable, _)| {
6427            (
6428                self.anchor_after(run_range.start)..self.anchor_before(run_range.end),
6429                runnable,
6430            )
6431        })
6432    }
6433
6434    pub fn line_indents(
6435        &self,
6436        start_row: MultiBufferRow,
6437        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6438    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6439        let max_point = self.max_point();
6440        let mut cursor = self.cursor::<Point, Point>();
6441        cursor.seek(&Point::new(start_row.0, 0));
6442        iter::from_fn(move || {
6443            let mut region = cursor.region()?;
6444            while !buffer_filter(&region.excerpt.buffer) {
6445                cursor.next();
6446                region = cursor.region()?;
6447            }
6448            let region = cursor.region()?;
6449            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6450            let buffer_start_row =
6451                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6452
6453            let buffer_end_row = if region.is_main_buffer
6454                && (region.has_trailing_newline || region.range.end == max_point)
6455            {
6456                region.buffer_range.end.row
6457            } else {
6458                region.buffer_range.end.row.saturating_sub(1)
6459            };
6460
6461            let line_indents = region
6462                .buffer
6463                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6464            let region_buffer_row = region.buffer_range.start.row;
6465            let region_row = region.range.start.row;
6466            let region_buffer = &region.excerpt.buffer;
6467            cursor.next();
6468            Some(line_indents.map(move |(buffer_row, indent)| {
6469                let row = region_row + (buffer_row - region_buffer_row);
6470                (MultiBufferRow(row), indent, region_buffer.as_ref())
6471            }))
6472        })
6473        .flatten()
6474    }
6475
6476    pub fn reversed_line_indents(
6477        &self,
6478        end_row: MultiBufferRow,
6479        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6480    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6481        let max_point = self.max_point();
6482        let mut cursor = self.cursor::<Point, Point>();
6483        cursor.seek(&Point::new(end_row.0, 0));
6484        iter::from_fn(move || {
6485            let mut region = cursor.region()?;
6486            while !buffer_filter(&region.excerpt.buffer) {
6487                cursor.prev();
6488                region = cursor.region()?;
6489            }
6490            let region = cursor.region()?;
6491
6492            let buffer_start_row = region.buffer_range.start.row;
6493            let buffer_end_row = if region.is_main_buffer
6494                && (region.has_trailing_newline || region.range.end == max_point)
6495            {
6496                region.buffer_range.end.row + 1
6497            } else {
6498                region.buffer_range.end.row
6499            };
6500
6501            let overshoot = end_row.0 - region.range.start.row;
6502            let buffer_end_row =
6503                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6504
6505            let line_indents = region
6506                .buffer
6507                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6508            let region_buffer_row = region.buffer_range.start.row;
6509            let region_row = region.range.start.row;
6510            let region_buffer = &region.excerpt.buffer;
6511            cursor.prev();
6512            Some(line_indents.map(move |(buffer_row, indent)| {
6513                let row = region_row + (buffer_row - region_buffer_row);
6514                (MultiBufferRow(row), indent, region_buffer.as_ref())
6515            }))
6516        })
6517        .flatten()
6518    }
6519
6520    pub async fn enclosing_indent(
6521        &self,
6522        mut target_row: MultiBufferRow,
6523    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6524        let max_row = MultiBufferRow(self.max_point().row);
6525        if target_row >= max_row {
6526            return None;
6527        }
6528
6529        let mut target_indent = self.line_indent_for_row(target_row);
6530
6531        // If the current row is at the start of an indented block, we want to return this
6532        // block as the enclosing indent.
6533        if !target_indent.is_line_empty() && target_row < max_row {
6534            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6535            if !next_line_indent.is_line_empty()
6536                && target_indent.raw_len() < next_line_indent.raw_len()
6537            {
6538                target_indent = next_line_indent;
6539                target_row.0 += 1;
6540            }
6541        }
6542
6543        const SEARCH_ROW_LIMIT: u32 = 25000;
6544        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6545        const YIELD_INTERVAL: u32 = 100;
6546
6547        let mut accessed_row_counter = 0;
6548
6549        // If there is a blank line at the current row, search for the next non indented lines
6550        if target_indent.is_line_empty() {
6551            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6552            let end =
6553                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6554
6555            let mut non_empty_line_above = None;
6556            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6557                if row < start {
6558                    break;
6559                }
6560                accessed_row_counter += 1;
6561                if accessed_row_counter == YIELD_INTERVAL {
6562                    accessed_row_counter = 0;
6563                    yield_now().await;
6564                }
6565                if !indent.is_line_empty() {
6566                    non_empty_line_above = Some((row, indent));
6567                    break;
6568                }
6569            }
6570
6571            let mut non_empty_line_below = None;
6572            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6573                if row > end {
6574                    break;
6575                }
6576                accessed_row_counter += 1;
6577                if accessed_row_counter == YIELD_INTERVAL {
6578                    accessed_row_counter = 0;
6579                    yield_now().await;
6580                }
6581                if !indent.is_line_empty() {
6582                    non_empty_line_below = Some((row, indent));
6583                    break;
6584                }
6585            }
6586
6587            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6588                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6589                    if above_indent.raw_len() >= below_indent.raw_len() {
6590                        (above_row, above_indent)
6591                    } else {
6592                        (below_row, below_indent)
6593                    }
6594                }
6595                (Some(above), None) => above,
6596                (None, Some(below)) => below,
6597                _ => return None,
6598            };
6599
6600            target_indent = indent;
6601            target_row = row;
6602        }
6603
6604        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6605        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6606
6607        let mut start_indent = None;
6608        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6609            if row < start {
6610                break;
6611            }
6612            accessed_row_counter += 1;
6613            if accessed_row_counter == YIELD_INTERVAL {
6614                accessed_row_counter = 0;
6615                yield_now().await;
6616            }
6617            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6618                start_indent = Some((row, indent));
6619                break;
6620            }
6621        }
6622        let (start_row, start_indent_size) = start_indent?;
6623
6624        let mut end_indent = (end, None);
6625        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6626            if row > end {
6627                break;
6628            }
6629            accessed_row_counter += 1;
6630            if accessed_row_counter == YIELD_INTERVAL {
6631                accessed_row_counter = 0;
6632                yield_now().await;
6633            }
6634            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6635                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6636                break;
6637            }
6638        }
6639        let (end_row, end_indent_size) = end_indent;
6640
6641        let indent = if let Some(end_indent_size) = end_indent_size {
6642            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6643                start_indent_size
6644            } else {
6645                end_indent_size
6646            }
6647        } else {
6648            start_indent_size
6649        };
6650
6651        Some((start_row..end_row, indent))
6652    }
6653
6654    pub fn indent_guides_in_range<T: ToPoint>(
6655        &self,
6656        range: Range<T>,
6657        ignore_disabled_for_language: bool,
6658        cx: &App,
6659    ) -> impl Iterator<Item = IndentGuide> {
6660        let range = range.start.to_point(self)..range.end.to_point(self);
6661        let start_row = MultiBufferRow(range.start.row);
6662        let end_row = MultiBufferRow(range.end.row);
6663
6664        let mut row_indents = self.line_indents(start_row, |buffer| {
6665            let settings = LanguageSettings::for_buffer_snapshot(buffer, None, cx);
6666            settings.indent_guides.enabled || ignore_disabled_for_language
6667        });
6668
6669        let mut result = Vec::new();
6670        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6671
6672        let mut prev_settings = None;
6673        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6674            if first_row > end_row {
6675                break;
6676            }
6677            let current_depth = indent_stack.len() as u32;
6678
6679            // Avoid retrieving the language settings repeatedly for every buffer row.
6680            if let Some((prev_buffer_id, _)) = &prev_settings
6681                && prev_buffer_id != &buffer.remote_id()
6682            {
6683                prev_settings.take();
6684            }
6685            let settings = &prev_settings
6686                .get_or_insert_with(|| {
6687                    (
6688                        buffer.remote_id(),
6689                        LanguageSettings::for_buffer_snapshot(buffer, None, cx),
6690                    )
6691                })
6692                .1;
6693            let tab_size = settings.tab_size.get();
6694
6695            // When encountering empty, continue until found useful line indent
6696            // then add to the indent stack with the depth found
6697            let mut found_indent = false;
6698            let mut last_row = first_row;
6699            if line_indent.is_line_blank() {
6700                while !found_indent {
6701                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6702                        break;
6703                    };
6704                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6705                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6706                        break;
6707                    }
6708
6709                    if new_line_indent.is_line_blank() {
6710                        continue;
6711                    }
6712                    last_row = target_row.min(end_row);
6713                    line_indent = new_line_indent;
6714                    found_indent = true;
6715                    break;
6716                }
6717            } else {
6718                found_indent = true
6719            }
6720
6721            let depth = if found_indent {
6722                line_indent.len(tab_size) / tab_size
6723            } else {
6724                0
6725            };
6726
6727            match depth.cmp(&current_depth) {
6728                cmp::Ordering::Less => {
6729                    for _ in 0..(current_depth - depth) {
6730                        let mut indent = indent_stack.pop().unwrap();
6731                        if last_row != first_row {
6732                            // In this case, we landed on an empty row, had to seek forward,
6733                            // and discovered that the indent we where on is ending.
6734                            // This means that the last display row must
6735                            // be on line that ends this indent range, so we
6736                            // should display the range up to the first non-empty line
6737                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6738                        }
6739
6740                        result.push(indent)
6741                    }
6742                }
6743                cmp::Ordering::Greater => {
6744                    for next_depth in current_depth..depth {
6745                        indent_stack.push(IndentGuide {
6746                            buffer_id: buffer.remote_id(),
6747                            start_row: first_row,
6748                            end_row: last_row,
6749                            depth: next_depth,
6750                            tab_size,
6751                            settings: settings.indent_guides.clone(),
6752                        });
6753                    }
6754                }
6755                _ => {}
6756            }
6757
6758            for indent in indent_stack.iter_mut() {
6759                indent.end_row = last_row;
6760            }
6761        }
6762
6763        result.extend(indent_stack);
6764        result.into_iter()
6765    }
6766
6767    pub fn trailing_excerpt_update_count(&self) -> usize {
6768        self.trailing_excerpt_update_count
6769    }
6770
6771    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6772        self.point_to_buffer_offset(point)
6773            .and_then(|(buffer, _)| buffer.file())
6774    }
6775
6776    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6777        self.point_to_buffer_offset(offset)
6778            .and_then(|(buffer, offset)| buffer.language_at(offset))
6779    }
6780
6781    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6782        self.excerpts
6783            .first()
6784            .map(|excerpt| &excerpt.buffer)
6785            .map(|buffer| LanguageSettings::for_buffer_snapshot(buffer, None, cx))
6786            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6787    }
6788
6789    pub fn language_settings_at<'a, T: ToOffset>(
6790        &'a self,
6791        point: T,
6792        cx: &'a App,
6793    ) -> Cow<'a, LanguageSettings> {
6794        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6795            buffer.settings_at(offset, cx)
6796        } else {
6797            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
6798        }
6799    }
6800
6801    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6802        self.point_to_buffer_offset(point)
6803            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6804    }
6805
6806    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6807        self.point_to_buffer_offset(point)
6808            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6809            .unwrap_or_default()
6810    }
6811
6812    pub fn language_indent_size_at<T: ToOffset>(
6813        &self,
6814        position: T,
6815        cx: &App,
6816    ) -> Option<IndentSize> {
6817        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6818        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6819    }
6820
6821    pub fn is_dirty(&self) -> bool {
6822        self.is_dirty
6823    }
6824
6825    pub fn has_deleted_file(&self) -> bool {
6826        self.has_deleted_file
6827    }
6828
6829    pub fn has_conflict(&self) -> bool {
6830        self.has_conflict
6831    }
6832
6833    pub fn has_diagnostics(&self) -> bool {
6834        self.excerpts
6835            .iter()
6836            .any(|excerpt| excerpt.buffer.has_diagnostics())
6837    }
6838
6839    pub fn diagnostic_group(
6840        &self,
6841        buffer_id: BufferId,
6842        group_id: usize,
6843    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6844        self.lift_buffer_metadata::<Point, _, _>(
6845            Point::zero()..self.max_point(),
6846            move |buffer, range| {
6847                if buffer.remote_id() != buffer_id {
6848                    return None;
6849                };
6850                Some(
6851                    buffer
6852                        .diagnostics_in_range(range, false)
6853                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6854                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6855                )
6856            },
6857        )
6858        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6859    }
6860
6861    pub fn diagnostics_in_range<'a, MBD>(
6862        &'a self,
6863        range: Range<MBD>,
6864    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6865    where
6866        MBD::TextDimension: 'a
6867            + text::ToOffset
6868            + text::FromAnchor
6869            + Sub<Output = MBD::TextDimension>
6870            + fmt::Debug
6871            + ops::Add<Output = MBD::TextDimension>
6872            + ops::AddAssign
6873            + Ord,
6874        MBD: MultiBufferDimension
6875            + Ord
6876            + Sub<Output = MBD::TextDimension>
6877            + ops::Add<MBD::TextDimension, Output = MBD>
6878            + ops::AddAssign<MBD::TextDimension>
6879            + 'a,
6880    {
6881        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6882            Some(
6883                buffer
6884                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6885                    .map(|entry| (entry.range, entry.diagnostic)),
6886            )
6887        })
6888        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6889    }
6890
6891    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6892        &'a self,
6893        range: Range<MBD>,
6894    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6895    where
6896        MBD: MultiBufferDimension
6897            + Ord
6898            + Sub<Output = MBD::TextDimension>
6899            + ops::Add<MBD::TextDimension, Output = MBD>
6900            + ops::AddAssign<MBD::TextDimension>,
6901        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6902            + ops::Add<Output = MBD::TextDimension>
6903            + text::ToOffset
6904            + text::FromAnchor
6905            + AddAssign<MBD::TextDimension>
6906            + Ord,
6907    {
6908        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6909            Some(
6910                buffer
6911                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6912                    .map(|entry| (entry.range, entry.diagnostic)),
6913            )
6914        })
6915        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6916    }
6917
6918    pub fn syntax_ancestor<T: ToOffset>(
6919        &self,
6920        range: Range<T>,
6921    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6922        let range = range.start.to_offset(self)..range.end.to_offset(self);
6923        let mut excerpt = self.excerpt_containing(range.clone())?;
6924        let node = excerpt
6925            .buffer()
6926            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6927        let node_range = node.byte_range();
6928        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6929        if !excerpt.contains_buffer_range(node_range.clone()) {
6930            return None;
6931        };
6932        Some((node, excerpt.map_range_from_buffer(node_range)))
6933    }
6934
6935    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6936        let (excerpt_id, _, buffer) = self.as_singleton()?;
6937        let outline = buffer.outline(theme);
6938        Some(Outline::new(
6939            outline
6940                .items
6941                .into_iter()
6942                .flat_map(|item| {
6943                    Some(OutlineItem {
6944                        depth: item.depth,
6945                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6946                        source_range_for_text: self
6947                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6948                        text: item.text,
6949                        highlight_ranges: item.highlight_ranges,
6950                        name_ranges: item.name_ranges,
6951                        body_range: item.body_range.and_then(|body_range| {
6952                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6953                        }),
6954                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6955                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6956                        }),
6957                    })
6958                })
6959                .collect(),
6960        ))
6961    }
6962
6963    pub fn symbols_containing<T: ToOffset>(
6964        &self,
6965        offset: T,
6966        theme: Option<&SyntaxTheme>,
6967    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6968        let anchor = self.anchor_before(offset);
6969        let excerpt @ &Excerpt {
6970            id: excerpt_id,
6971            buffer_id,
6972            ref buffer,
6973            ..
6974        } = self.excerpt(anchor.excerpt_id)?;
6975        if cfg!(debug_assertions) {
6976            match anchor.text_anchor.buffer_id {
6977                // we clearly are hitting this according to sentry, but in what situations can this occur?
6978                Some(anchor_buffer_id) => {
6979                    assert_eq!(
6980                        anchor_buffer_id, buffer_id,
6981                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6982                    )
6983                }
6984                None => assert!(anchor.is_max()),
6985            }
6986        };
6987        Some((
6988            buffer_id,
6989            buffer
6990                .symbols_containing(anchor.text_anchor, theme)
6991                .into_iter()
6992                .flat_map(|item| {
6993                    Some(OutlineItem {
6994                        depth: item.depth,
6995                        source_range_for_text: Anchor::range_in_buffer(
6996                            excerpt_id,
6997                            item.source_range_for_text,
6998                        ),
6999                        range: Anchor::range_in_buffer(excerpt_id, item.range),
7000                        text: item.text,
7001                        highlight_ranges: item.highlight_ranges,
7002                        name_ranges: item.name_ranges,
7003                        body_range: item
7004                            .body_range
7005                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
7006                        annotation_range: item
7007                            .annotation_range
7008                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
7009                    })
7010                })
7011                .collect(),
7012        ))
7013    }
7014
7015    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
7016        self.try_excerpt_locator_for_id(id)
7017            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
7018    }
7019
7020    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
7021        if id == ExcerptId::min() {
7022            Some(Locator::min_ref())
7023        } else if id == ExcerptId::max() {
7024            Some(Locator::max_ref())
7025        } else {
7026            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
7027            if let Some(entry) = item
7028                && entry.id == id
7029            {
7030                return Some(&entry.locator);
7031            }
7032            None
7033        }
7034    }
7035
7036    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
7037    fn excerpt_locators_for_ids(
7038        &self,
7039        ids: impl IntoIterator<Item = ExcerptId>,
7040    ) -> SmallVec<[Locator; 1]> {
7041        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
7042        sorted_ids.sort_unstable();
7043        sorted_ids.dedup();
7044        let mut locators = SmallVec::new();
7045
7046        while sorted_ids.last() == Some(&ExcerptId::max()) {
7047            sorted_ids.pop();
7048            locators.push(Locator::max());
7049        }
7050
7051        let mut sorted_ids = sorted_ids.into_iter().peekable();
7052        locators.extend(
7053            sorted_ids
7054                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
7055                .map(|_| Locator::min()),
7056        );
7057
7058        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
7059        for id in sorted_ids {
7060            if cursor.seek_forward(&id, Bias::Left) {
7061                locators.push(cursor.item().unwrap().locator.clone());
7062            } else {
7063                panic!("invalid excerpt id {:?}", id);
7064            }
7065        }
7066
7067        locators.sort_unstable();
7068        locators
7069    }
7070
7071    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
7072        Some(self.excerpt(excerpt_id)?.buffer_id)
7073    }
7074
7075    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7076        Some(&self.excerpt(excerpt_id)?.buffer)
7077    }
7078
7079    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7080        let mut cursor = self
7081            .excerpts
7082            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7083        let locator = self.excerpt_locator_for_id(excerpt_id);
7084        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7085        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7086            sought_exact = true;
7087            cursor.prev();
7088        } else if excerpt_id == ExcerptId::min() {
7089            sought_exact = true;
7090        }
7091        if sought_exact {
7092            let start = cursor.start().1;
7093            let end = cursor.end().1;
7094            let mut diff_transforms = self
7095                .diff_transforms
7096                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7097            diff_transforms.seek(&start, Bias::Left);
7098            let overshoot = start - diff_transforms.start().0;
7099            let start = diff_transforms.start().1 + overshoot;
7100            diff_transforms.seek(&end, Bias::Right);
7101            let overshoot = end - diff_transforms.start().0;
7102            let end = diff_transforms.start().1 + overshoot;
7103            Some(start.0..end.0)
7104        } else {
7105            None
7106        }
7107    }
7108
7109    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7110    /// to have the latest excerpt id for the one passed in and will also remap
7111    /// `ExcerptId::max()` to the corresponding excertp ID.
7112    ///
7113    /// Callers of this function should generally use the resulting excerpt's `id` field
7114    /// afterwards.
7115    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7116        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7117        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7118        let (_, _, item) =
7119            self.excerpts
7120                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7121        if let Some(excerpt) = item
7122            && excerpt.id == excerpt_id
7123        {
7124            return Some(excerpt);
7125        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7126            return self.excerpts.last();
7127        }
7128        None
7129    }
7130
7131    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7132    pub fn excerpt_containing<T: ToOffset>(
7133        &self,
7134        range: Range<T>,
7135    ) -> Option<MultiBufferExcerpt<'_>> {
7136        let range = range.start.to_offset(self)..range.end.to_offset(self);
7137        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7138        cursor.seek(&range.start);
7139
7140        let start_excerpt = cursor.excerpt()?;
7141        if range.end != range.start {
7142            cursor.seek_forward(&range.end);
7143            if cursor.excerpt()?.id != start_excerpt.id {
7144                return None;
7145            }
7146        }
7147
7148        cursor.seek_to_start_of_current_excerpt();
7149        let region = cursor.region()?;
7150        let offset = region.range.start;
7151        let buffer_offset = start_excerpt.buffer_start_offset();
7152        let excerpt_offset = *cursor.excerpts.start();
7153        Some(MultiBufferExcerpt {
7154            diff_transforms: cursor.diff_transforms,
7155            excerpt: start_excerpt,
7156            offset,
7157            buffer_offset,
7158            excerpt_offset,
7159        })
7160    }
7161
7162    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7163        if let Some(id) = anchor.text_anchor.buffer_id {
7164            return Some(id);
7165        }
7166        let excerpt = self.excerpt_containing(anchor..anchor)?;
7167        Some(excerpt.buffer_id())
7168    }
7169
7170    pub fn selections_in_range<'a>(
7171        &'a self,
7172        range: &'a Range<Anchor>,
7173        include_local: bool,
7174    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7175        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7176        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7177        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7178        cursor.seek(start_locator, Bias::Left);
7179        cursor
7180            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7181            .flat_map(move |excerpt| {
7182                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7183                if excerpt.id == range.start.excerpt_id {
7184                    query_range.start = range.start.text_anchor;
7185                }
7186                if excerpt.id == range.end.excerpt_id {
7187                    query_range.end = range.end.text_anchor;
7188                }
7189
7190                excerpt
7191                    .buffer
7192                    .selections_in_range(query_range, include_local)
7193                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7194                        selections.map(move |selection| {
7195                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7196                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7197                            if range.start.cmp(&start, self).is_gt() {
7198                                start = range.start;
7199                            }
7200                            if range.end.cmp(&end, self).is_lt() {
7201                                end = range.end;
7202                            }
7203
7204                            (
7205                                replica_id,
7206                                line_mode,
7207                                cursor_shape,
7208                                Selection {
7209                                    id: selection.id,
7210                                    start,
7211                                    end,
7212                                    reversed: selection.reversed,
7213                                    goal: selection.goal,
7214                                },
7215                            )
7216                        })
7217                    })
7218            })
7219    }
7220
7221    pub fn show_headers(&self) -> bool {
7222        self.show_headers
7223    }
7224
7225    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7226        self.diff_state(buffer_id).map(|diff| &diff.diff)
7227    }
7228
7229    fn diff_state(&self, buffer_id: BufferId) -> Option<&DiffStateSnapshot> {
7230        find_diff_state(&self.diffs, buffer_id)
7231    }
7232
7233    pub fn total_changed_lines(&self) -> (u32, u32) {
7234        let summary = self.diffs.summary();
7235        (summary.added_rows, summary.removed_rows)
7236    }
7237
7238    pub fn all_diff_hunks_expanded(&self) -> bool {
7239        self.all_diff_hunks_expanded
7240    }
7241
7242    /// Visually annotates a position or range with the `Debug` representation of a value. The
7243    /// callsite of this function is used as a key - previous annotations will be removed.
7244    #[cfg(debug_assertions)]
7245    #[track_caller]
7246    pub fn debug<V, R>(&self, ranges: &R, value: V)
7247    where
7248        R: debug::ToMultiBufferDebugRanges,
7249        V: std::fmt::Debug,
7250    {
7251        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7252    }
7253
7254    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7255    /// debug annotations with the same key will be removed. The key is also used to determine the
7256    /// annotation's color.
7257    #[cfg(debug_assertions)]
7258    #[track_caller]
7259    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7260    where
7261        K: std::hash::Hash + 'static,
7262        R: debug::ToMultiBufferDebugRanges,
7263        V: std::fmt::Debug,
7264    {
7265        let text_ranges = ranges
7266            .to_multi_buffer_debug_ranges(self)
7267            .into_iter()
7268            .flat_map(|range| {
7269                self.range_to_buffer_ranges(range.start..=range.end)
7270                    .into_iter()
7271                    .map(|(buffer, range, _excerpt_id)| {
7272                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7273                    })
7274            })
7275            .collect();
7276        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7277            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7278        });
7279    }
7280
7281    fn excerpt_edits_for_diff_change(
7282        &self,
7283        buffer_state: &BufferState,
7284        diff_change_range: Range<usize>,
7285    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7286        let mut excerpt_edits = Vec::new();
7287        for locator in &buffer_state.excerpts {
7288            let mut cursor = self
7289                .excerpts
7290                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7291            cursor.seek_forward(&Some(locator), Bias::Left);
7292            if let Some(excerpt) = cursor.item()
7293                && excerpt.locator == *locator
7294            {
7295                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7296                if diff_change_range.end < excerpt_buffer_range.start
7297                    || diff_change_range.start > excerpt_buffer_range.end
7298                {
7299                    continue;
7300                }
7301                let excerpt_start = cursor.start().1;
7302                let excerpt_len = excerpt.text_summary.len;
7303                let diff_change_start_in_excerpt = diff_change_range
7304                    .start
7305                    .saturating_sub(excerpt_buffer_range.start);
7306                let diff_change_end_in_excerpt = diff_change_range
7307                    .end
7308                    .saturating_sub(excerpt_buffer_range.start);
7309                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7310                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7311                excerpt_edits.push(Edit {
7312                    old: edit_start..edit_end,
7313                    new: edit_start..edit_end,
7314                });
7315            }
7316        }
7317        excerpt_edits
7318    }
7319
7320    /// Returns the number of graphemes in `range`.
7321    ///
7322    /// This counts user-visible characters like `e\u{301}` as one.
7323    pub fn grapheme_count_for_range(&self, range: &Range<MultiBufferOffset>) -> usize {
7324        self.text_for_range(range.clone())
7325            .collect::<String>()
7326            .graphemes(true)
7327            .count()
7328    }
7329}
7330
7331#[cfg(any(test, feature = "test-support"))]
7332impl MultiBufferSnapshot {
7333    pub fn random_byte_range(
7334        &self,
7335        start_offset: MultiBufferOffset,
7336        rng: &mut impl rand::Rng,
7337    ) -> Range<MultiBufferOffset> {
7338        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7339        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7340        start..end
7341    }
7342
7343    #[cfg(any(test, feature = "test-support"))]
7344    fn check_invariants(&self) {
7345        let excerpts = self.excerpts.items(());
7346        let excerpt_ids = self.excerpt_ids.items(());
7347
7348        for (ix, excerpt) in excerpts.iter().enumerate() {
7349            if ix == 0 {
7350                if excerpt.locator <= Locator::min() {
7351                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7352                }
7353            } else if excerpt.locator <= excerpts[ix - 1].locator {
7354                panic!("excerpts are out-of-order: {:?}", excerpts);
7355            }
7356        }
7357
7358        for (ix, entry) in excerpt_ids.iter().enumerate() {
7359            if ix == 0 {
7360                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7361                    panic!("invalid first excerpt id {:?}", entry.id);
7362                }
7363            } else if entry.id <= excerpt_ids[ix - 1].id {
7364                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7365            }
7366        }
7367
7368        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7369            panic!(
7370                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7371                self.excerpts.summary().text,
7372                self.diff_transforms.summary().input,
7373                self.diff_transforms.items(()),
7374            );
7375        }
7376
7377        let mut prev_transform: Option<&DiffTransform> = None;
7378        for item in self.diff_transforms.iter() {
7379            if let DiffTransform::BufferContent {
7380                summary,
7381                inserted_hunk_info,
7382            } = item
7383            {
7384                if let Some(DiffTransform::BufferContent {
7385                    inserted_hunk_info: prev_inserted_hunk_info,
7386                    ..
7387                }) = prev_transform
7388                    && *inserted_hunk_info == *prev_inserted_hunk_info
7389                {
7390                    panic!(
7391                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7392                        self.diff_transforms.items(())
7393                    );
7394                }
7395                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7396                    panic!("empty buffer content transform");
7397                }
7398            }
7399            prev_transform = Some(item);
7400        }
7401    }
7402}
7403
7404impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7405where
7406    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7407    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7408{
7409    #[instrument(skip_all)]
7410    fn seek(&mut self, position: &MBD) {
7411        let position = OutputDimension(*position);
7412        self.cached_region.take();
7413        self.diff_transforms.seek(&position, Bias::Right);
7414        if self.diff_transforms.item().is_none()
7415            && self.diff_transforms.start().output_dimension == position
7416        {
7417            self.diff_transforms.prev();
7418        }
7419
7420        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7421        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7422            let overshoot = position - self.diff_transforms.start().output_dimension;
7423            excerpt_position += overshoot;
7424        }
7425
7426        self.excerpts.seek(&excerpt_position, Bias::Right);
7427        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7428            self.excerpts.prev();
7429        }
7430    }
7431
7432    fn seek_forward(&mut self, position: &MBD) {
7433        let position = OutputDimension(*position);
7434        self.cached_region.take();
7435        self.diff_transforms.seek_forward(&position, Bias::Right);
7436        if self.diff_transforms.item().is_none()
7437            && self.diff_transforms.start().output_dimension == position
7438        {
7439            self.diff_transforms.prev();
7440        }
7441
7442        let overshoot = position - self.diff_transforms.start().output_dimension;
7443        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7444        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7445            excerpt_position += overshoot;
7446        }
7447
7448        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7449        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7450            self.excerpts.prev();
7451        }
7452    }
7453
7454    fn next_excerpt(&mut self) {
7455        self.excerpts.next();
7456        self.seek_to_start_of_current_excerpt();
7457    }
7458
7459    fn prev_excerpt(&mut self) {
7460        self.excerpts.prev();
7461        self.seek_to_start_of_current_excerpt();
7462    }
7463
7464    fn seek_to_start_of_current_excerpt(&mut self) {
7465        self.cached_region.take();
7466
7467        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7468            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7469            && self.diff_transforms.next_item().is_some()
7470        {
7471            self.diff_transforms.next();
7472        }
7473    }
7474
7475    fn next_excerpt_forwards(&mut self) {
7476        self.excerpts.next();
7477        self.seek_to_start_of_current_excerpt_forward();
7478    }
7479
7480    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7481        self.cached_region.take();
7482
7483        if self
7484            .diff_transforms
7485            .seek_forward(self.excerpts.start(), Bias::Left)
7486            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7487            && self.diff_transforms.next_item().is_some()
7488        {
7489            self.diff_transforms.next();
7490        }
7491    }
7492
7493    fn next(&mut self) {
7494        self.cached_region.take();
7495        match self
7496            .diff_transforms
7497            .end()
7498            .excerpt_dimension
7499            .cmp(&self.excerpts.end())
7500        {
7501            cmp::Ordering::Less => self.diff_transforms.next(),
7502            cmp::Ordering::Greater => self.excerpts.next(),
7503            cmp::Ordering::Equal => {
7504                self.diff_transforms.next();
7505                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7506                    || self.diff_transforms.item().is_none()
7507                {
7508                    self.excerpts.next();
7509                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7510                    self.diff_transforms.item()
7511                    && self
7512                        .excerpts
7513                        .item()
7514                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7515                {
7516                    self.excerpts.next();
7517                }
7518            }
7519        }
7520    }
7521
7522    fn prev(&mut self) {
7523        self.cached_region.take();
7524        match self
7525            .diff_transforms
7526            .start()
7527            .excerpt_dimension
7528            .cmp(self.excerpts.start())
7529        {
7530            cmp::Ordering::Less => self.excerpts.prev(),
7531            cmp::Ordering::Greater => self.diff_transforms.prev(),
7532            cmp::Ordering::Equal => {
7533                self.diff_transforms.prev();
7534                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7535                    || self.diff_transforms.item().is_none()
7536                {
7537                    self.excerpts.prev();
7538                }
7539            }
7540        }
7541    }
7542
7543    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7544        self.cached_region
7545            .get_or_init(|| self.build_region())
7546            .as_ref()
7547    }
7548
7549    fn is_at_start_of_excerpt(&mut self) -> bool {
7550        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7551            return false;
7552        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7553            return true;
7554        }
7555
7556        self.diff_transforms.prev();
7557        let prev_transform = self.diff_transforms.item();
7558        self.diff_transforms.next();
7559
7560        prev_transform.is_none_or(|next_transform| {
7561            matches!(next_transform, DiffTransform::BufferContent { .. })
7562        })
7563    }
7564
7565    fn is_at_end_of_excerpt(&self) -> bool {
7566        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7567            return false;
7568        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7569            || self.diff_transforms.item().is_none()
7570        {
7571            return true;
7572        }
7573
7574        let next_transform = self.diff_transforms.next_item();
7575        next_transform.is_none_or(|next_transform| match next_transform {
7576            DiffTransform::BufferContent { .. } => true,
7577            DiffTransform::DeletedHunk { hunk_info, .. } => self
7578                .excerpts
7579                .item()
7580                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7581        })
7582    }
7583
7584    fn main_buffer_position(&self) -> Option<BD> {
7585        let excerpt = self.excerpts.item()?;
7586        let buffer = &excerpt.buffer;
7587        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7588        let mut buffer_start = buffer_context_start;
7589        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7590        buffer_start += overshoot;
7591        Some(buffer_start)
7592    }
7593
7594    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7595        let excerpt = self.excerpts.item()?;
7596        match self.diff_transforms.item()? {
7597            DiffTransform::DeletedHunk {
7598                buffer_id,
7599                base_text_byte_range,
7600                has_trailing_newline,
7601                hunk_info,
7602                ..
7603            } => {
7604                let diff = find_diff_state(self.diffs, *buffer_id)?;
7605                let buffer = diff.base_text();
7606                let mut rope_cursor = buffer.as_rope().cursor(0);
7607                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7608                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7609                let mut buffer_end = buffer_start;
7610                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7611                let start = self.diff_transforms.start().output_dimension.0;
7612                let end = self.diff_transforms.end().output_dimension.0;
7613                Some(MultiBufferRegion {
7614                    buffer,
7615                    excerpt,
7616                    has_trailing_newline: *has_trailing_newline,
7617                    is_main_buffer: false,
7618                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7619                        hunk_info.hunk_secondary_status,
7620                    )),
7621                    buffer_range: buffer_start..buffer_end,
7622                    range: start..end,
7623                })
7624            }
7625            DiffTransform::BufferContent {
7626                inserted_hunk_info, ..
7627            } => {
7628                let buffer = &excerpt.buffer;
7629                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7630
7631                let mut start = self.diff_transforms.start().output_dimension.0;
7632                let mut buffer_start = buffer_context_start;
7633                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7634                    let overshoot =
7635                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7636                    start += overshoot;
7637                } else {
7638                    let overshoot =
7639                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7640                    buffer_start += overshoot;
7641                }
7642
7643                let mut end;
7644                let mut buffer_end;
7645                let has_trailing_newline;
7646                let transform_end = self.diff_transforms.end();
7647                if transform_end.excerpt_dimension < self.excerpts.end() {
7648                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7649                    end = transform_end.output_dimension.0;
7650                    buffer_end = buffer_context_start;
7651                    buffer_end += overshoot;
7652                    has_trailing_newline = false;
7653                } else {
7654                    let overshoot =
7655                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7656                    end = self.diff_transforms.start().output_dimension.0;
7657                    end += overshoot;
7658                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7659                    has_trailing_newline = excerpt.has_trailing_newline;
7660                };
7661
7662                let diff_hunk_status = inserted_hunk_info.map(|info| {
7663                    if info.is_logically_deleted {
7664                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7665                    } else {
7666                        DiffHunkStatus::added(info.hunk_secondary_status)
7667                    }
7668                });
7669
7670                Some(MultiBufferRegion {
7671                    buffer,
7672                    excerpt,
7673                    has_trailing_newline,
7674                    is_main_buffer: true,
7675                    diff_hunk_status,
7676                    buffer_range: buffer_start..buffer_end,
7677                    range: start..end,
7678                })
7679            }
7680        }
7681    }
7682
7683    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7684        let excerpt = self.excerpts.item()?;
7685        match self.diff_transforms.item()? {
7686            &DiffTransform::DeletedHunk { .. } => {
7687                let start = self.diff_transforms.start().output_dimension.0;
7688                let end = self.diff_transforms.end().output_dimension.0;
7689                Some((excerpt, start..end))
7690            }
7691            DiffTransform::BufferContent { .. } => {
7692                let mut start = self.diff_transforms.start().output_dimension.0;
7693                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7694                    let overshoot =
7695                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7696                    start += overshoot;
7697                }
7698
7699                let mut end;
7700                let transform_end = self.diff_transforms.end();
7701                if transform_end.excerpt_dimension < self.excerpts.end() {
7702                    end = transform_end.output_dimension.0;
7703                } else {
7704                    let overshoot =
7705                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7706                    end = self.diff_transforms.start().output_dimension.0;
7707                    end += overshoot;
7708                };
7709
7710                Some((excerpt, start..end))
7711            }
7712        }
7713    }
7714
7715    fn excerpt(&self) -> Option<&'a Excerpt> {
7716        self.excerpts.item()
7717    }
7718}
7719
7720impl Excerpt {
7721    fn new(
7722        id: ExcerptId,
7723        locator: Locator,
7724        buffer_id: BufferId,
7725        buffer: Arc<BufferSnapshot>,
7726        range: ExcerptRange<text::Anchor>,
7727        has_trailing_newline: bool,
7728    ) -> Self {
7729        Excerpt {
7730            id,
7731            locator,
7732            max_buffer_row: range.context.end.to_point(&buffer).row,
7733            text_summary: buffer
7734                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7735            buffer_id,
7736            buffer,
7737            range,
7738            has_trailing_newline,
7739        }
7740    }
7741
7742    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7743        let content_start = self.range.context.start.to_offset(&self.buffer);
7744        let chunks_start = content_start + range.start;
7745        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7746
7747        let has_footer = self.has_trailing_newline
7748            && range.start <= self.text_summary.len
7749            && range.end > self.text_summary.len;
7750
7751        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7752
7753        ExcerptChunks {
7754            excerpt_id: self.id,
7755            content_chunks,
7756            has_footer,
7757        }
7758    }
7759
7760    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7761        let content_start = self.range.context.start.to_offset(&self.buffer);
7762        let chunks_start = content_start + range.start;
7763        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7764        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7765        excerpt_chunks.has_footer = self.has_trailing_newline
7766            && range.start <= self.text_summary.len
7767            && range.end > self.text_summary.len;
7768    }
7769
7770    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7771        if text_anchor
7772            .cmp(&self.range.context.start, &self.buffer)
7773            .is_lt()
7774        {
7775            self.range.context.start
7776        } else if text_anchor
7777            .cmp(&self.range.context.end, &self.buffer)
7778            .is_gt()
7779        {
7780            self.range.context.end
7781        } else {
7782            text_anchor
7783        }
7784    }
7785
7786    fn contains(&self, anchor: &Anchor) -> bool {
7787        (anchor.text_anchor.buffer_id == None
7788            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7789            && self
7790                .range
7791                .context
7792                .start
7793                .cmp(&anchor.text_anchor, &self.buffer)
7794                .is_le()
7795            && self
7796                .range
7797                .context
7798                .end
7799                .cmp(&anchor.text_anchor, &self.buffer)
7800                .is_ge()
7801    }
7802
7803    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7804    fn buffer_start_offset(&self) -> BufferOffset {
7805        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7806    }
7807
7808    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7809    fn buffer_end_offset(&self) -> BufferOffset {
7810        self.buffer_start_offset() + self.text_summary.len
7811    }
7812}
7813
7814impl<'a> MultiBufferExcerpt<'a> {
7815    pub fn id(&self) -> ExcerptId {
7816        self.excerpt.id
7817    }
7818
7819    pub fn buffer_id(&self) -> BufferId {
7820        self.excerpt.buffer_id
7821    }
7822
7823    pub fn start_anchor(&self) -> Anchor {
7824        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7825    }
7826
7827    pub fn end_anchor(&self) -> Anchor {
7828        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7829    }
7830
7831    pub fn buffer(&self) -> &'a BufferSnapshot {
7832        &self.excerpt.buffer
7833    }
7834
7835    pub fn buffer_range(&self) -> Range<BufferOffset> {
7836        self.buffer_offset
7837            ..BufferOffset(
7838                self.excerpt
7839                    .range
7840                    .context
7841                    .end
7842                    .to_offset(&self.excerpt.buffer.text),
7843            )
7844    }
7845
7846    pub fn start_offset(&self) -> MultiBufferOffset {
7847        self.offset
7848    }
7849
7850    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7851    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7852        self.map_range_to_buffer(offset..offset).start
7853    }
7854
7855    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7856    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7857        self.diff_transforms
7858            .seek(&OutputDimension(range.start), Bias::Right);
7859        let start = self.map_offset_to_buffer_internal(range.start);
7860        let end = if range.end > range.start {
7861            self.diff_transforms
7862                .seek_forward(&OutputDimension(range.end), Bias::Right);
7863            self.map_offset_to_buffer_internal(range.end)
7864        } else {
7865            start
7866        };
7867        start..end
7868    }
7869
7870    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7871        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7872        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7873            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7874        };
7875        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7876        self.buffer_offset + offset_in_excerpt
7877    }
7878
7879    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7880    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7881        self.map_range_from_buffer(buffer_offset..buffer_offset)
7882            .start
7883    }
7884
7885    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7886    pub fn map_range_from_buffer(
7887        &mut self,
7888        buffer_range: Range<BufferOffset>,
7889    ) -> Range<MultiBufferOffset> {
7890        if buffer_range.start < self.buffer_offset {
7891            log::warn!(
7892                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7893            );
7894            return self.offset..self.offset;
7895        }
7896        let overshoot = buffer_range.start - self.buffer_offset;
7897        let excerpt_offset = self.excerpt_offset + overshoot;
7898        let excerpt_seek_dim = excerpt_offset;
7899        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7900        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7901            log::warn!(
7902                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7903            );
7904            return self.offset..self.offset;
7905        }
7906        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7907        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7908
7909        let end = if buffer_range.start < buffer_range.end {
7910            let overshoot = buffer_range.end - self.buffer_offset;
7911            let excerpt_offset = self.excerpt_offset + overshoot;
7912            let excerpt_seek_dim = excerpt_offset;
7913            self.diff_transforms
7914                .seek_forward(&excerpt_seek_dim, Bias::Right);
7915            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7916            // todo(lw): Clamp end to the excerpt boundaries
7917            self.diff_transforms.start().output_dimension.0 + overshoot
7918        } else {
7919            start
7920        };
7921
7922        start..end
7923    }
7924
7925    /// Returns true if the entirety of the given range is in the buffer's excerpt
7926    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7927        range.start >= self.excerpt.buffer_start_offset()
7928            && range.end <= self.excerpt.buffer_end_offset()
7929    }
7930
7931    /// Returns true if any part of the given range is in the buffer's excerpt
7932    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7933        range.start <= self.excerpt.buffer_end_offset()
7934            && range.end >= self.excerpt.buffer_start_offset()
7935    }
7936
7937    pub fn max_buffer_row(&self) -> u32 {
7938        self.excerpt.max_buffer_row
7939    }
7940}
7941
7942impl ExcerptId {
7943    pub fn min() -> Self {
7944        Self(0)
7945    }
7946
7947    pub fn max() -> Self {
7948        Self(u32::MAX)
7949    }
7950
7951    pub fn to_proto(self) -> u64 {
7952        self.0 as _
7953    }
7954
7955    pub fn from_proto(proto: u64) -> Self {
7956        Self(proto as _)
7957    }
7958
7959    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7960        let a = snapshot.excerpt_locator_for_id(*self);
7961        let b = snapshot.excerpt_locator_for_id(*other);
7962        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7963    }
7964}
7965
7966impl From<ExcerptId> for usize {
7967    fn from(val: ExcerptId) -> Self {
7968        val.0 as usize
7969    }
7970}
7971
7972impl fmt::Debug for Excerpt {
7973    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7974        f.debug_struct("Excerpt")
7975            .field("id", &self.id)
7976            .field("locator", &self.locator)
7977            .field("buffer_id", &self.buffer_id)
7978            .field("range", &self.range)
7979            .field("text_summary", &self.text_summary)
7980            .field("has_trailing_newline", &self.has_trailing_newline)
7981            .finish()
7982    }
7983}
7984
7985impl sum_tree::Item for Excerpt {
7986    type Summary = ExcerptSummary;
7987
7988    fn summary(&self, _cx: ()) -> Self::Summary {
7989        let mut text = self.text_summary;
7990        if self.has_trailing_newline {
7991            text += TextSummary::from("\n");
7992        }
7993        ExcerptSummary {
7994            excerpt_id: self.id,
7995            excerpt_locator: self.locator.clone(),
7996            widest_line_number: self.max_buffer_row,
7997            text: text.into(),
7998            count: 1,
7999        }
8000    }
8001}
8002
8003impl sum_tree::Item for ExcerptIdMapping {
8004    type Summary = ExcerptId;
8005
8006    fn summary(&self, _cx: ()) -> Self::Summary {
8007        self.id
8008    }
8009}
8010
8011impl sum_tree::KeyedItem for ExcerptIdMapping {
8012    type Key = ExcerptId;
8013
8014    fn key(&self) -> Self::Key {
8015        self.id
8016    }
8017}
8018
8019impl DiffTransform {
8020    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
8021        match self {
8022            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
8023            DiffTransform::BufferContent {
8024                inserted_hunk_info, ..
8025            } => *inserted_hunk_info,
8026        }
8027    }
8028}
8029
8030impl sum_tree::Item for DiffTransform {
8031    type Summary = DiffTransformSummary;
8032
8033    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
8034        match self {
8035            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
8036                input: *summary,
8037                output: *summary,
8038            },
8039            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
8040                input: MBTextSummary::default(),
8041                output: summary.into(),
8042            },
8043        }
8044    }
8045}
8046
8047impl DiffTransformSummary {
8048    fn excerpt_len(&self) -> ExcerptOffset {
8049        ExcerptDimension(self.input.len)
8050    }
8051}
8052
8053impl sum_tree::ContextLessSummary for DiffTransformSummary {
8054    fn zero() -> Self {
8055        DiffTransformSummary {
8056            input: MBTextSummary::default(),
8057            output: MBTextSummary::default(),
8058        }
8059    }
8060
8061    fn add_summary(&mut self, other: &Self) {
8062        self.input += other.input;
8063        self.output += other.output;
8064    }
8065}
8066
8067impl sum_tree::ContextLessSummary for ExcerptId {
8068    fn zero() -> Self {
8069        Self(0)
8070    }
8071
8072    fn add_summary(&mut self, summary: &Self) {
8073        *self = cmp::max(*self, *summary);
8074    }
8075}
8076
8077impl sum_tree::ContextLessSummary for ExcerptSummary {
8078    fn zero() -> Self {
8079        Self::default()
8080    }
8081
8082    fn add_summary(&mut self, summary: &Self) {
8083        debug_assert!(
8084            summary.excerpt_locator > self.excerpt_locator
8085                || self.excerpt_locator == Locator::min(),
8086            "Excerpt locators must be in ascending order: {:?} > {:?}",
8087            summary.excerpt_locator,
8088            self.excerpt_locator
8089        );
8090        self.excerpt_locator = summary.excerpt_locator.clone();
8091        self.text += summary.text;
8092        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
8093        self.count += summary.count;
8094    }
8095}
8096
8097impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8098    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8099        Ord::cmp(&Some(self), cursor_location)
8100    }
8101}
8102
8103impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8104    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8105        Ord::cmp(self, &cursor_location.excerpt_locator)
8106    }
8107}
8108
8109impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8110where
8111    MBD: MultiBufferDimension + Default,
8112{
8113    fn zero(_: ()) -> Self {
8114        ExcerptDimension(MBD::default())
8115    }
8116
8117    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8118        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8119    }
8120}
8121
8122impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8123    fn zero(_cx: ()) -> Self {
8124        Default::default()
8125    }
8126
8127    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8128        *self = Some(&summary.excerpt_locator);
8129    }
8130}
8131
8132impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8133    fn zero(_cx: ()) -> Self {
8134        Default::default()
8135    }
8136
8137    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8138        *self = Some(summary.excerpt_id);
8139    }
8140}
8141
8142#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8143struct OutputDimension<T>(T);
8144
8145impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8146    fn eq(&self, other: &T) -> bool {
8147        self.0 == *other
8148    }
8149}
8150
8151impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8152    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8153        self.0.partial_cmp(other)
8154    }
8155}
8156
8157impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8158where
8159    T: ops::Sub<U, Output = R>,
8160{
8161    type Output = R;
8162
8163    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8164        self.0 - other.0
8165    }
8166}
8167
8168impl<R, T, U> ops::Add<U> for OutputDimension<T>
8169where
8170    T: ops::Add<U, Output = R>,
8171{
8172    type Output = OutputDimension<R>;
8173
8174    fn add(self, other: U) -> Self::Output {
8175        OutputDimension(self.0 + other)
8176    }
8177}
8178
8179impl<T, U> AddAssign<U> for OutputDimension<T>
8180where
8181    T: AddAssign<U>,
8182{
8183    fn add_assign(&mut self, other: U) {
8184        self.0 += other;
8185    }
8186}
8187
8188impl<T, U> SubAssign<U> for OutputDimension<T>
8189where
8190    T: SubAssign<U>,
8191{
8192    fn sub_assign(&mut self, other: U) {
8193        self.0 -= other;
8194    }
8195}
8196
8197#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8198struct ExcerptDimension<T>(T);
8199
8200impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8201    fn eq(&self, other: &T) -> bool {
8202        self.0 == *other
8203    }
8204}
8205
8206impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8207    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8208        self.0.partial_cmp(other)
8209    }
8210}
8211
8212impl ExcerptOffset {
8213    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8214        self.0.saturating_sub(other.0)
8215    }
8216}
8217
8218impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8219where
8220    T: ops::Sub<U, Output = R>,
8221{
8222    type Output = R;
8223
8224    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8225        self.0 - other.0
8226    }
8227}
8228
8229impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8230where
8231    T: ops::Add<U, Output = R>,
8232{
8233    type Output = ExcerptDimension<R>;
8234
8235    fn add(self, other: U) -> Self::Output {
8236        ExcerptDimension(self.0 + other)
8237    }
8238}
8239
8240impl<T, U> AddAssign<U> for ExcerptDimension<T>
8241where
8242    T: AddAssign<U>,
8243{
8244    fn add_assign(&mut self, other: U) {
8245        self.0 += other;
8246    }
8247}
8248
8249impl<T, U> SubAssign<U> for ExcerptDimension<T>
8250where
8251    T: SubAssign<U>,
8252{
8253    fn sub_assign(&mut self, other: U) {
8254        self.0 -= other;
8255    }
8256}
8257
8258impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8259    fn zero(_: ()) -> Self {
8260        MultiBufferOffset::ZERO
8261    }
8262
8263    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8264        *self += summary.output.len;
8265    }
8266}
8267
8268impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8269    for ExcerptDimension<MBD>
8270where
8271    MBD: MultiBufferDimension + Ord,
8272{
8273    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8274        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8275    }
8276}
8277
8278impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8279    for ExcerptDimension<MBD>
8280where
8281    MBD: MultiBufferDimension + Ord,
8282{
8283    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8284        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8285    }
8286}
8287
8288impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8289    for ExcerptDimension<MBD>
8290{
8291    fn zero(_: ()) -> Self {
8292        ExcerptDimension(MBD::default())
8293    }
8294
8295    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8296        self.0.add_mb_text_summary(&summary.input)
8297    }
8298}
8299
8300impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8301    for OutputDimension<MBD>
8302where
8303    MBD: MultiBufferDimension + Ord,
8304{
8305    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8306        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8307    }
8308}
8309
8310impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8311    for OutputDimension<MBD>
8312{
8313    fn zero(_: ()) -> Self {
8314        OutputDimension(MBD::default())
8315    }
8316
8317    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8318        self.0.add_mb_text_summary(&summary.output)
8319    }
8320}
8321
8322impl MultiBufferRows<'_> {
8323    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8324        self.point = Point::new(row, 0);
8325        self.cursor.seek(&self.point);
8326    }
8327}
8328
8329impl Iterator for MultiBufferRows<'_> {
8330    type Item = RowInfo;
8331
8332    fn next(&mut self) -> Option<Self::Item> {
8333        if self.is_empty && self.point.row == 0 {
8334            self.point += Point::new(1, 0);
8335            return Some(RowInfo {
8336                buffer_id: None,
8337                buffer_row: Some(0),
8338                multibuffer_row: Some(MultiBufferRow(0)),
8339                diff_status: None,
8340                expand_info: None,
8341                wrapped_buffer_row: None,
8342            });
8343        }
8344
8345        let mut region = self.cursor.region()?.clone();
8346        while self.point >= region.range.end {
8347            self.cursor.next();
8348            if let Some(next_region) = self.cursor.region() {
8349                region = next_region.clone();
8350            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8351                let multibuffer_row = MultiBufferRow(self.point.row);
8352                let last_excerpt = self
8353                    .cursor
8354                    .excerpts
8355                    .item()
8356                    .or(self.cursor.excerpts.prev_item())?;
8357                let last_row = last_excerpt
8358                    .range
8359                    .context
8360                    .end
8361                    .to_point(&last_excerpt.buffer)
8362                    .row;
8363
8364                let first_row = last_excerpt
8365                    .range
8366                    .context
8367                    .start
8368                    .to_point(&last_excerpt.buffer)
8369                    .row;
8370
8371                let expand_info = if self.is_singleton {
8372                    None
8373                } else {
8374                    let needs_expand_up = first_row == last_row
8375                        && last_row > 0
8376                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8377                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8378
8379                    if needs_expand_up && needs_expand_down {
8380                        Some(ExpandExcerptDirection::UpAndDown)
8381                    } else if needs_expand_up {
8382                        Some(ExpandExcerptDirection::Up)
8383                    } else if needs_expand_down {
8384                        Some(ExpandExcerptDirection::Down)
8385                    } else {
8386                        None
8387                    }
8388                    .map(|direction| ExpandInfo {
8389                        direction,
8390                        excerpt_id: last_excerpt.id,
8391                    })
8392                };
8393                self.point += Point::new(1, 0);
8394                return Some(RowInfo {
8395                    buffer_id: Some(last_excerpt.buffer_id),
8396                    buffer_row: Some(last_row),
8397                    multibuffer_row: Some(multibuffer_row),
8398                    diff_status: None,
8399                    wrapped_buffer_row: None,
8400                    expand_info,
8401                });
8402            } else {
8403                return None;
8404            };
8405        }
8406
8407        let overshoot = self.point - region.range.start;
8408        let buffer_point = region.buffer_range.start + overshoot;
8409        let expand_info = if self.is_singleton {
8410            None
8411        } else {
8412            let needs_expand_up = self.point.row == region.range.start.row
8413                && self.cursor.is_at_start_of_excerpt()
8414                && buffer_point.row > 0;
8415            let needs_expand_down = (region.excerpt.has_trailing_newline
8416                && self.point.row + 1 == region.range.end.row
8417                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8418                && self.cursor.is_at_end_of_excerpt()
8419                && buffer_point.row < region.buffer.max_point().row;
8420
8421            if needs_expand_up && needs_expand_down {
8422                Some(ExpandExcerptDirection::UpAndDown)
8423            } else if needs_expand_up {
8424                Some(ExpandExcerptDirection::Up)
8425            } else if needs_expand_down {
8426                Some(ExpandExcerptDirection::Down)
8427            } else {
8428                None
8429            }
8430            .map(|direction| ExpandInfo {
8431                direction,
8432                excerpt_id: region.excerpt.id,
8433            })
8434        };
8435
8436        let result = Some(RowInfo {
8437            buffer_id: Some(region.buffer.remote_id()),
8438            buffer_row: Some(buffer_point.row),
8439            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8440            diff_status: region
8441                .diff_hunk_status
8442                .filter(|_| self.point < region.range.end),
8443            expand_info,
8444            wrapped_buffer_row: None,
8445        });
8446        self.point += Point::new(1, 0);
8447        result
8448    }
8449}
8450
8451impl<'a> MultiBufferChunks<'a> {
8452    pub fn offset(&self) -> MultiBufferOffset {
8453        self.range.start
8454    }
8455
8456    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8457        self.diff_transforms.seek(&range.end, Bias::Right);
8458        let mut excerpt_end = self.diff_transforms.start().1;
8459        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8460            let overshoot = range.end - self.diff_transforms.start().0;
8461            excerpt_end += overshoot;
8462        }
8463
8464        self.diff_transforms.seek(&range.start, Bias::Right);
8465        let mut excerpt_start = self.diff_transforms.start().1;
8466        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8467            let overshoot = range.start - self.diff_transforms.start().0;
8468            excerpt_start += overshoot;
8469        }
8470
8471        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8472        self.buffer_chunk.take();
8473        self.range = range;
8474    }
8475
8476    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8477        self.excerpt_offset_range = new_range.clone();
8478        self.excerpts.seek(&new_range.start, Bias::Right);
8479        if let Some(excerpt) = self.excerpts.item() {
8480            let excerpt_start = *self.excerpts.start();
8481            if let Some(excerpt_chunks) = self
8482                .excerpt_chunks
8483                .as_mut()
8484                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8485            {
8486                excerpt.seek_chunks(
8487                    excerpt_chunks,
8488                    (self.excerpt_offset_range.start - excerpt_start)
8489                        ..(self.excerpt_offset_range.end - excerpt_start),
8490                );
8491            } else {
8492                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8493                    (self.excerpt_offset_range.start - excerpt_start)
8494                        ..(self.excerpt_offset_range.end - excerpt_start),
8495                    self.language_aware,
8496                ));
8497            }
8498        } else {
8499            self.excerpt_chunks = None;
8500        }
8501    }
8502
8503    #[ztracing::instrument(skip_all)]
8504    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8505        loop {
8506            if self.excerpt_offset_range.is_empty() {
8507                return None;
8508            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8509                self.excerpt_offset_range.start += chunk.text.len();
8510                return Some(chunk);
8511            } else {
8512                self.excerpts.next();
8513                let excerpt = self.excerpts.item()?;
8514                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8515                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8516                    self.language_aware,
8517                ));
8518            }
8519        }
8520    }
8521}
8522
8523impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8524    type Item = &'a str;
8525
8526    fn next(&mut self) -> Option<Self::Item> {
8527        let mut region = self.cursor.region()?;
8528        if self.offset == region.range.start {
8529            self.cursor.prev();
8530            region = self.cursor.region()?;
8531            let start_overshoot = self.start.saturating_sub(region.range.start);
8532            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8533                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8534            ));
8535        }
8536
8537        if self.offset == region.range.end && region.has_trailing_newline {
8538            self.offset -= 1;
8539            Some("\n")
8540        } else {
8541            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8542            self.offset -= chunk.len();
8543            Some(chunk)
8544        }
8545    }
8546}
8547
8548impl<'a> Iterator for MultiBufferChunks<'a> {
8549    type Item = Chunk<'a>;
8550
8551    #[ztracing::instrument(skip_all)]
8552    fn next(&mut self) -> Option<Chunk<'a>> {
8553        if self.range.start >= self.range.end {
8554            return None;
8555        }
8556        if self.range.start == self.diff_transforms.end().0 {
8557            self.diff_transforms.next();
8558        }
8559
8560        let diff_transform_start = self.diff_transforms.start().0;
8561        let diff_transform_end = self.diff_transforms.end().0;
8562        debug_assert!(
8563            self.range.start < diff_transform_end,
8564            "{:?} < {:?} of ({1:?}..{2:?})",
8565            self.range.start,
8566            diff_transform_end,
8567            diff_transform_start
8568        );
8569
8570        let diff_transform = self.diff_transforms.item()?;
8571        match diff_transform {
8572            DiffTransform::BufferContent { .. } => {
8573                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8574                    chunk
8575                } else {
8576                    let chunk = self.next_excerpt_chunk().unwrap();
8577                    self.buffer_chunk.insert(chunk)
8578                };
8579
8580                let chunk_end = self.range.start + chunk.text.len();
8581                let diff_transform_end = diff_transform_end.min(self.range.end);
8582
8583                if diff_transform_end < chunk_end {
8584                    let split_idx = diff_transform_end - self.range.start;
8585                    let (before, after) = chunk.text.split_at(split_idx);
8586                    self.range.start = diff_transform_end;
8587                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8588                    let chars = chunk.chars & mask;
8589                    let tabs = chunk.tabs & mask;
8590                    let newlines = chunk.newlines & mask;
8591
8592                    chunk.text = after;
8593                    chunk.chars = chunk.chars >> split_idx;
8594                    chunk.tabs = chunk.tabs >> split_idx;
8595                    chunk.newlines = chunk.newlines >> split_idx;
8596
8597                    Some(Chunk {
8598                        text: before,
8599                        chars,
8600                        tabs,
8601                        newlines,
8602                        ..chunk.clone()
8603                    })
8604                } else {
8605                    self.range.start = chunk_end;
8606                    self.buffer_chunk.take()
8607                }
8608            }
8609            DiffTransform::DeletedHunk {
8610                buffer_id,
8611                base_text_byte_range,
8612                has_trailing_newline,
8613                ..
8614            } => {
8615                let base_text_start =
8616                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8617                let base_text_end =
8618                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8619                let base_text_end = base_text_end.min(base_text_byte_range.end);
8620
8621                let mut chunks = if let Some((_, mut chunks)) = self
8622                    .diff_base_chunks
8623                    .take()
8624                    .filter(|(id, _)| id == buffer_id)
8625                {
8626                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8627                    {
8628                        chunks.seek(base_text_start..base_text_end);
8629                    }
8630                    chunks
8631                } else {
8632                    let base_buffer = &find_diff_state(self.diffs, *buffer_id)?.base_text();
8633                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8634                };
8635
8636                let chunk = if let Some(chunk) = chunks.next() {
8637                    self.range.start += chunk.text.len();
8638                    self.diff_base_chunks = Some((*buffer_id, chunks));
8639                    chunk
8640                } else {
8641                    debug_assert!(has_trailing_newline);
8642                    self.range.start += "\n".len();
8643                    Chunk {
8644                        text: "\n",
8645                        chars: 1u128,
8646                        newlines: 1u128,
8647                        ..Default::default()
8648                    }
8649                };
8650                Some(chunk)
8651            }
8652        }
8653    }
8654}
8655
8656impl MultiBufferBytes<'_> {
8657    fn consume(&mut self, len: usize) {
8658        self.range.start += len;
8659        self.chunk = &self.chunk[len..];
8660
8661        if !self.range.is_empty() && self.chunk.is_empty() {
8662            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8663                self.chunk = chunk;
8664            } else if self.has_trailing_newline {
8665                self.has_trailing_newline = false;
8666                self.chunk = b"\n";
8667            } else {
8668                self.cursor.next();
8669                if let Some(region) = self.cursor.region() {
8670                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8671                        region.buffer_range.start
8672                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8673                                .min(region.buffer_range.end),
8674                    );
8675                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8676                    self.excerpt_bytes = Some(excerpt_bytes);
8677                    self.has_trailing_newline =
8678                        region.has_trailing_newline && self.range.end >= region.range.end;
8679                    if self.chunk.is_empty() && self.has_trailing_newline {
8680                        self.has_trailing_newline = false;
8681                        self.chunk = b"\n";
8682                    }
8683                }
8684            }
8685        }
8686    }
8687}
8688
8689impl<'a> Iterator for MultiBufferBytes<'a> {
8690    type Item = &'a [u8];
8691
8692    fn next(&mut self) -> Option<Self::Item> {
8693        let chunk = self.chunk;
8694        if chunk.is_empty() {
8695            None
8696        } else {
8697            self.consume(chunk.len());
8698            Some(chunk)
8699        }
8700    }
8701}
8702
8703impl io::Read for MultiBufferBytes<'_> {
8704    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8705        let len = cmp::min(buf.len(), self.chunk.len());
8706        buf[..len].copy_from_slice(&self.chunk[..len]);
8707        if len > 0 {
8708            self.consume(len);
8709        }
8710        Ok(len)
8711    }
8712}
8713
8714impl io::Read for ReversedMultiBufferBytes<'_> {
8715    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8716        let len = cmp::min(buf.len(), self.chunk.len());
8717        buf[..len].copy_from_slice(&self.chunk[..len]);
8718        buf[..len].reverse();
8719        if len > 0 {
8720            self.range.end -= len;
8721            self.chunk = &self.chunk[..self.chunk.len() - len];
8722            if !self.range.is_empty()
8723                && self.chunk.is_empty()
8724                && let Some(chunk) = self.chunks.next()
8725            {
8726                self.chunk = chunk.as_bytes();
8727            }
8728        }
8729        Ok(len)
8730    }
8731}
8732
8733impl<'a> Iterator for ExcerptChunks<'a> {
8734    type Item = Chunk<'a>;
8735
8736    fn next(&mut self) -> Option<Self::Item> {
8737        if let Some(chunk) = self.content_chunks.next() {
8738            return Some(chunk);
8739        }
8740
8741        if self.has_footer {
8742            let text = "\n";
8743            let chars = 0b1;
8744            let newlines = 0b1;
8745            self.has_footer = false;
8746            return Some(Chunk {
8747                text,
8748                chars,
8749                newlines,
8750                ..Default::default()
8751            });
8752        }
8753
8754        None
8755    }
8756}
8757
8758impl ToOffset for Point {
8759    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8760        snapshot.point_to_offset(*self)
8761    }
8762    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8763        snapshot.point_to_offset_utf16(*self)
8764    }
8765}
8766
8767impl ToOffset for MultiBufferOffset {
8768    #[track_caller]
8769    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8770        assert!(
8771            *self <= snapshot.len(),
8772            "offset {} is greater than the snapshot.len() {}",
8773            self.0,
8774            snapshot.len().0,
8775        );
8776        *self
8777    }
8778    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8779        snapshot.offset_to_offset_utf16(*self)
8780    }
8781}
8782
8783impl ToOffset for MultiBufferOffsetUtf16 {
8784    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8785        snapshot.offset_utf16_to_offset(*self)
8786    }
8787
8788    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8789        *self
8790    }
8791}
8792
8793impl ToOffset for PointUtf16 {
8794    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8795        snapshot.point_utf16_to_offset(*self)
8796    }
8797    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8798        snapshot.point_utf16_to_offset_utf16(*self)
8799    }
8800}
8801
8802impl ToPoint for MultiBufferOffset {
8803    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8804        snapshot.offset_to_point(*self)
8805    }
8806    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8807        snapshot.offset_to_point_utf16(*self)
8808    }
8809}
8810
8811impl ToPoint for Point {
8812    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8813        *self
8814    }
8815    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8816        snapshot.point_to_point_utf16(*self)
8817    }
8818}
8819
8820impl ToPoint for PointUtf16 {
8821    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8822        snapshot.point_utf16_to_point(*self)
8823    }
8824    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8825        *self
8826    }
8827}
8828
8829impl From<ExcerptId> for EntityId {
8830    fn from(id: ExcerptId) -> Self {
8831        EntityId::from(id.0 as u64)
8832    }
8833}
8834
8835#[cfg(debug_assertions)]
8836pub mod debug {
8837    use super::*;
8838
8839    pub trait ToMultiBufferDebugRanges {
8840        fn to_multi_buffer_debug_ranges(
8841            &self,
8842            snapshot: &MultiBufferSnapshot,
8843        ) -> Vec<Range<MultiBufferOffset>>;
8844    }
8845
8846    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8847        fn to_multi_buffer_debug_ranges(
8848            &self,
8849            snapshot: &MultiBufferSnapshot,
8850        ) -> Vec<Range<MultiBufferOffset>> {
8851            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8852        }
8853    }
8854
8855    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8856        fn to_multi_buffer_debug_ranges(
8857            &self,
8858            snapshot: &MultiBufferSnapshot,
8859        ) -> Vec<Range<MultiBufferOffset>> {
8860            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8861                .to_multi_buffer_debug_ranges(snapshot)
8862        }
8863    }
8864
8865    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8866        fn to_multi_buffer_debug_ranges(
8867            &self,
8868            snapshot: &MultiBufferSnapshot,
8869        ) -> Vec<Range<MultiBufferOffset>> {
8870            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8871        }
8872    }
8873
8874    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8875        fn to_multi_buffer_debug_ranges(
8876            &self,
8877            snapshot: &MultiBufferSnapshot,
8878        ) -> Vec<Range<MultiBufferOffset>> {
8879            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8880        }
8881    }
8882
8883    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8884        fn to_multi_buffer_debug_ranges(
8885            &self,
8886            snapshot: &MultiBufferSnapshot,
8887        ) -> Vec<Range<MultiBufferOffset>> {
8888            self.iter()
8889                .map(|item| {
8890                    let offset = item.to_offset(snapshot);
8891                    offset..offset
8892                })
8893                .collect()
8894        }
8895    }
8896
8897    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8898        fn to_multi_buffer_debug_ranges(
8899            &self,
8900            snapshot: &MultiBufferSnapshot,
8901        ) -> Vec<Range<MultiBufferOffset>> {
8902            self.iter()
8903                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8904                .collect()
8905        }
8906    }
8907}