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