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