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