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