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