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