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