multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunk, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter, WeakEntity};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState,
  23    File, IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16,
  24    Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, AddAssign, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::Arc,
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58
  59pub use self::path_key::PathKey;
  60
  61#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  62pub struct ExcerptId(u32);
  63
  64/// One or more [`Buffers`](Buffer) being edited in a single view.
  65///
  66/// See <https://zed.dev/features#multi-buffers>
  67pub struct MultiBuffer {
  68    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  69    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  70    snapshot: RefCell<MultiBufferSnapshot>,
  71    /// Contains the state of the buffers being edited
  72    buffers: HashMap<BufferId, BufferState>,
  73    /// Mapping from path keys to their excerpts.
  74    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  75    /// Mapping from excerpt IDs to their path key.
  76    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  77    /// Mapping from buffer IDs to their diff states
  78    diffs: HashMap<BufferId, DiffState>,
  79    subscriptions: Topic<MultiBufferOffset>,
  80    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  81    singleton: bool,
  82    /// The history of the multi-buffer.
  83    history: History,
  84    /// The explicit title of the multi-buffer.
  85    /// If `None`, it will be derived from the underlying path or content.
  86    title: Option<String>,
  87    /// The writing capability of the multi-buffer.
  88    capability: Capability,
  89    buffer_changed_since_sync: Rc<Cell<bool>>,
  90}
  91
  92#[derive(Clone, Debug, PartialEq, Eq)]
  93pub enum Event {
  94    ExcerptsAdded {
  95        buffer: Entity<Buffer>,
  96        predecessor: ExcerptId,
  97        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  98    },
  99    ExcerptsRemoved {
 100        ids: Vec<ExcerptId>,
 101        removed_buffer_ids: Vec<BufferId>,
 102    },
 103    ExcerptsExpanded {
 104        ids: Vec<ExcerptId>,
 105    },
 106    ExcerptsEdited {
 107        excerpt_ids: Vec<ExcerptId>,
 108        buffer_ids: Vec<BufferId>,
 109    },
 110    DiffHunksToggled,
 111    Edited {
 112        edited_buffer: Option<Entity<Buffer>>,
 113    },
 114    TransactionUndone {
 115        transaction_id: TransactionId,
 116    },
 117    Reloaded,
 118    LanguageChanged(BufferId),
 119    Reparsed(BufferId),
 120    Saved,
 121    FileHandleChanged,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124    BufferDiffChanged,
 125}
 126
 127/// A diff hunk, representing a range of consequent lines in a multibuffer.
 128#[derive(Debug, Clone, PartialEq, Eq)]
 129pub struct MultiBufferDiffHunk {
 130    /// The row range in the multibuffer where this diff hunk appears.
 131    pub row_range: Range<MultiBufferRow>,
 132    /// The buffer ID that this hunk belongs to.
 133    pub buffer_id: BufferId,
 134    /// The range of the underlying buffer that this hunk corresponds to.
 135    pub buffer_range: Range<text::Anchor>,
 136    /// The excerpt that contains the diff hunk.
 137    pub excerpt_id: ExcerptId,
 138    /// The range within the buffer's diff base that this hunk corresponds to.
 139    pub diff_base_byte_range: Range<BufferOffset>,
 140    /// Whether or not this hunk also appears in the 'secondary diff'.
 141    pub secondary_status: DiffHunkSecondaryStatus,
 142    /// The word diffs for this hunk.
 143    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 163            && self.buffer_range.start.is_min()
 164            && self.buffer_range.end.is_max()
 165    }
 166
 167    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 168        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 169        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 170        start..end
 171    }
 172}
 173
 174pub type MultiBufferPoint = Point;
 175type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 176type ExcerptPoint = ExcerptDimension<Point>;
 177
 178#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 179#[serde(transparent)]
 180pub struct MultiBufferRow(pub u32);
 181
 182impl MultiBufferRow {
 183    pub const MIN: Self = Self(0);
 184    pub const MAX: Self = Self(u32::MAX);
 185}
 186
 187impl ops::Add<usize> for MultiBufferRow {
 188    type Output = Self;
 189
 190    fn add(self, rhs: usize) -> Self::Output {
 191        MultiBufferRow(self.0 + rhs as u32)
 192    }
 193}
 194
 195pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 196    type TextDimension: TextDimension;
 197    fn from_summary(summary: &MBTextSummary) -> Self;
 198
 199    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 200
 201    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 202}
 203
 204// todo(lw): MultiBufferPoint
 205impl MultiBufferDimension for Point {
 206    type TextDimension = Point;
 207    fn from_summary(summary: &MBTextSummary) -> Self {
 208        summary.lines
 209    }
 210
 211    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 212        *self += *other;
 213    }
 214
 215    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 216        *self += summary.lines;
 217    }
 218}
 219
 220// todo(lw): MultiBufferPointUtf16
 221impl MultiBufferDimension for PointUtf16 {
 222    type TextDimension = PointUtf16;
 223    fn from_summary(summary: &MBTextSummary) -> Self {
 224        summary.lines_utf16()
 225    }
 226
 227    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 228        *self += *other;
 229    }
 230
 231    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 232        *self += summary.lines_utf16();
 233    }
 234}
 235
 236#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 237pub struct MultiBufferOffset(pub usize);
 238
 239impl fmt::Display for MultiBufferOffset {
 240    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 241        write!(f, "{}", self.0)
 242    }
 243}
 244
 245impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 246    type Sampler = MultiBufferOffsetUniformSampler;
 247}
 248
 249pub struct MultiBufferOffsetUniformSampler {
 250    sampler: rand::distr::uniform::UniformUsize,
 251}
 252
 253impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 254    type X = MultiBufferOffset;
 255
 256    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 257    where
 258        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 260    {
 261        let low = *low_b.borrow();
 262        let high = *high_b.borrow();
 263        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 264        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 265    }
 266
 267    #[inline] // if the range is constant, this helps LLVM to do the
 268    // calculations at compile-time.
 269    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 270    where
 271        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 273    {
 274        let low = *low_b.borrow();
 275        let high = *high_b.borrow();
 276        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 277        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 278    }
 279
 280    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 281        MultiBufferOffset(self.sampler.sample(rng))
 282    }
 283}
 284impl MultiBufferDimension for MultiBufferOffset {
 285    type TextDimension = usize;
 286    fn from_summary(summary: &MBTextSummary) -> Self {
 287        summary.len
 288    }
 289
 290    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 291        self.0 += *other;
 292    }
 293
 294    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 295        *self += summary.len;
 296    }
 297}
 298impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 299    type TextDimension = OffsetUtf16;
 300    fn from_summary(summary: &MBTextSummary) -> Self {
 301        MultiBufferOffsetUtf16(summary.len_utf16)
 302    }
 303
 304    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 305        self.0 += *other;
 306    }
 307
 308    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 309        self.0 += summary.len_utf16;
 310    }
 311}
 312
 313#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 314pub struct BufferOffset(pub usize);
 315
 316impl TextDimension for BufferOffset {
 317    fn from_text_summary(summary: &TextSummary) -> Self {
 318        BufferOffset(usize::from_text_summary(summary))
 319    }
 320    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 321        BufferOffset(usize::from_chunk(chunk))
 322    }
 323    fn add_assign(&mut self, other: &Self) {
 324        TextDimension::add_assign(&mut self.0, &other.0);
 325    }
 326}
 327impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 328    fn zero(cx: ()) -> Self {
 329        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 330    }
 331
 332    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 333        usize::add_summary(&mut self.0, summary, cx);
 334    }
 335}
 336
 337impl Sub for BufferOffset {
 338    type Output = usize;
 339
 340    fn sub(self, other: BufferOffset) -> Self::Output {
 341        self.0 - other.0
 342    }
 343}
 344
 345impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 346    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 347        self.0 += other.key;
 348    }
 349}
 350
 351impl language::ToPoint for BufferOffset {
 352    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 353        self.0.to_point(snapshot)
 354    }
 355}
 356
 357impl language::ToPointUtf16 for BufferOffset {
 358    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 359        self.0.to_point_utf16(snapshot)
 360    }
 361}
 362
 363impl language::ToOffset for BufferOffset {
 364    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 365        self.0.to_offset(snapshot)
 366    }
 367}
 368
 369impl language::ToOffsetUtf16 for BufferOffset {
 370    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 371        self.0.to_offset_utf16(snapshot)
 372    }
 373}
 374
 375#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 376pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 377
 378impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 379    type Output = MultiBufferOffsetUtf16;
 380
 381    fn add(self, rhs: usize) -> Self::Output {
 382        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 383    }
 384}
 385
 386impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 387    fn add_assign(&mut self, rhs: OffsetUtf16) {
 388        self.0 += rhs;
 389    }
 390}
 391
 392impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 393    fn add_assign(&mut self, rhs: usize) {
 394        self.0.0 += rhs;
 395    }
 396}
 397
 398impl Sub for MultiBufferOffsetUtf16 {
 399    type Output = OffsetUtf16;
 400
 401    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 402        self.0 - other.0
 403    }
 404}
 405
 406#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 407pub struct BufferOffsetUtf16(pub OffsetUtf16);
 408
 409impl MultiBufferOffset {
 410    const ZERO: Self = Self(0);
 411    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 412        self.0.saturating_sub(other.0)
 413    }
 414    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 415        MultiBufferOffset(self.0.saturating_sub(other))
 416    }
 417}
 418
 419impl ops::Sub for MultiBufferOffset {
 420    type Output = usize;
 421
 422    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 423        self.0 - other.0
 424    }
 425}
 426
 427impl ops::Sub<usize> for MultiBufferOffset {
 428    type Output = Self;
 429
 430    fn sub(self, other: usize) -> Self::Output {
 431        MultiBufferOffset(self.0 - other)
 432    }
 433}
 434
 435impl ops::SubAssign<usize> for MultiBufferOffset {
 436    fn sub_assign(&mut self, other: usize) {
 437        self.0 -= other;
 438    }
 439}
 440
 441impl ops::Add<usize> for BufferOffset {
 442    type Output = Self;
 443
 444    fn add(self, rhs: usize) -> Self::Output {
 445        BufferOffset(self.0 + rhs)
 446    }
 447}
 448
 449impl ops::AddAssign<usize> for BufferOffset {
 450    fn add_assign(&mut self, other: usize) {
 451        self.0 += other;
 452    }
 453}
 454
 455impl ops::Add<usize> for MultiBufferOffset {
 456    type Output = Self;
 457
 458    fn add(self, rhs: usize) -> Self::Output {
 459        MultiBufferOffset(self.0 + rhs)
 460    }
 461}
 462
 463impl ops::AddAssign<usize> for MultiBufferOffset {
 464    fn add_assign(&mut self, other: usize) {
 465        self.0 += other;
 466    }
 467}
 468
 469impl ops::Add<isize> for MultiBufferOffset {
 470    type Output = Self;
 471
 472    fn add(self, rhs: isize) -> Self::Output {
 473        MultiBufferOffset((self.0 as isize + rhs) as usize)
 474    }
 475}
 476
 477impl ops::Add for MultiBufferOffset {
 478    type Output = Self;
 479
 480    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 481        MultiBufferOffset(self.0 + rhs.0)
 482    }
 483}
 484
 485impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 486    fn add_assign(&mut self, other: MultiBufferOffset) {
 487        self.0 += other.0;
 488    }
 489}
 490
 491pub trait ToOffset: 'static + fmt::Debug {
 492    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 493    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 494}
 495
 496pub trait ToPoint: 'static + fmt::Debug {
 497    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 498    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 499}
 500
 501struct BufferState {
 502    buffer: Entity<Buffer>,
 503    last_version: RefCell<clock::Global>,
 504    last_non_text_state_update_count: Cell<usize>,
 505    excerpts: Vec<Locator>,
 506    _subscriptions: [gpui::Subscription; 2],
 507}
 508
 509struct DiffState {
 510    diff: Entity<BufferDiff>,
 511    /// Whether the [`MultiBuffer`] this is associated with is inverted (i.e.
 512    /// showing additions as deletions). This is used in the side-by-side diff
 513    /// view.
 514    ///
 515    /// The [`DiffState`]s in a [`MultiBuffer`] must either be all inverted, or
 516    // all not inverted.
 517    main_buffer: Option<WeakEntity<Buffer>>,
 518    _subscription: gpui::Subscription,
 519}
 520
 521impl DiffState {
 522    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 523        DiffStateSnapshot {
 524            diff: self.diff.read(cx).snapshot(cx),
 525            main_buffer: self.main_buffer.as_ref().and_then(|main_buffer| {
 526                main_buffer
 527                    .read_with(cx, |main_buffer, _| main_buffer.snapshot())
 528                    .ok()
 529            }),
 530        }
 531    }
 532}
 533
 534#[derive(Clone)]
 535struct DiffStateSnapshot {
 536    diff: BufferDiffSnapshot,
 537    main_buffer: Option<BufferSnapshot>,
 538}
 539
 540impl std::ops::Deref for DiffStateSnapshot {
 541    type Target = BufferDiffSnapshot;
 542
 543    fn deref(&self) -> &Self::Target {
 544        &self.diff
 545    }
 546}
 547
 548impl DiffState {
 549    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 550        DiffState {
 551            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 552                BufferDiffEvent::DiffChanged {
 553                    changed_range,
 554                    base_text_changed_range: _,
 555                } => {
 556                    if let Some(changed_range) = changed_range.clone() {
 557                        this.buffer_diff_changed(diff, changed_range, cx)
 558                    }
 559                    cx.emit(Event::BufferDiffChanged);
 560                }
 561                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 562                _ => {}
 563            }),
 564            diff,
 565            main_buffer: None,
 566        }
 567    }
 568
 569    fn new_inverted(
 570        diff: Entity<BufferDiff>,
 571        base_text_buffer_id: BufferId,
 572        main_buffer: Entity<Buffer>,
 573        cx: &mut Context<MultiBuffer>,
 574    ) -> Self {
 575        let main_buffer = main_buffer.downgrade();
 576        DiffState {
 577            _subscription: cx.subscribe(&diff, {
 578                let main_buffer = main_buffer.clone();
 579                move |this, diff, event, cx| match event {
 580                    BufferDiffEvent::DiffChanged {
 581                        changed_range: _,
 582                        base_text_changed_range,
 583                    } => {
 584                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 585                            this.inverted_buffer_diff_changed(
 586                                diff,
 587                                base_text_changed_range,
 588                                base_text_buffer_id,
 589                                main_buffer.clone(),
 590                                cx,
 591                            )
 592                        }
 593                        cx.emit(Event::BufferDiffChanged);
 594                    }
 595                    BufferDiffEvent::LanguageChanged => this.inverted_buffer_diff_language_changed(
 596                        base_text_buffer_id,
 597                        diff,
 598                        main_buffer.clone(),
 599                        cx,
 600                    ),
 601                    _ => {}
 602                }
 603            }),
 604            diff,
 605            main_buffer: Some(main_buffer),
 606        }
 607    }
 608}
 609
 610/// The contents of a [`MultiBuffer`] at a single point in time.
 611#[derive(Clone, Default)]
 612pub struct MultiBufferSnapshot {
 613    excerpts: SumTree<Excerpt>,
 614    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 615    diff_transforms: SumTree<DiffTransform>,
 616    non_text_state_update_count: usize,
 617    edit_count: usize,
 618    is_dirty: bool,
 619    has_deleted_file: bool,
 620    has_conflict: bool,
 621    /// immutable fields
 622    singleton: bool,
 623    excerpt_ids: SumTree<ExcerptIdMapping>,
 624    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 625    trailing_excerpt_update_count: usize,
 626    all_diff_hunks_expanded: bool,
 627    // FIXME
 628    pub show_deleted_hunks: bool,
 629    show_headers: bool,
 630}
 631
 632// follower: None
 633// - BufferContent(Some)
 634// - BufferContent(None)
 635// - DeletedHunk
 636//
 637// follower: Some
 638// - BufferContent(Some)
 639// - BufferContent(None)
 640
 641#[derive(Debug, Clone)]
 642enum DiffTransform {
 643    // RealText
 644    BufferContent {
 645        summary: MBTextSummary,
 646        // modified_hunk_info
 647        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 648    },
 649    // ExpandedHunkText
 650    DeletedHunk {
 651        summary: TextSummary,
 652        buffer_id: BufferId,
 653        hunk_info: DiffTransformHunkInfo,
 654        base_text_byte_range: Range<usize>,
 655        has_trailing_newline: bool,
 656    },
 657}
 658
 659#[derive(Clone, Copy, Debug)]
 660struct DiffTransformHunkInfo {
 661    excerpt_id: ExcerptId,
 662    hunk_start_anchor: text::Anchor,
 663    hunk_secondary_status: DiffHunkSecondaryStatus,
 664    is_logically_deleted: bool,
 665}
 666
 667impl Eq for DiffTransformHunkInfo {}
 668
 669impl PartialEq for DiffTransformHunkInfo {
 670    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 671        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 672    }
 673}
 674
 675impl std::hash::Hash for DiffTransformHunkInfo {
 676    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 677        self.excerpt_id.hash(state);
 678        self.hunk_start_anchor.hash(state);
 679    }
 680}
 681
 682#[derive(Clone)]
 683pub struct ExcerptInfo {
 684    pub id: ExcerptId,
 685    pub buffer: BufferSnapshot,
 686    pub buffer_id: BufferId,
 687    pub range: ExcerptRange<text::Anchor>,
 688    pub end_row: MultiBufferRow,
 689}
 690
 691impl std::fmt::Debug for ExcerptInfo {
 692    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 693        f.debug_struct(type_name::<Self>())
 694            .field("id", &self.id)
 695            .field("buffer_id", &self.buffer_id)
 696            .field("path", &self.buffer.file().map(|f| f.path()))
 697            .field("range", &self.range)
 698            .finish()
 699    }
 700}
 701
 702/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 703#[derive(Debug)]
 704pub struct ExcerptBoundary {
 705    pub prev: Option<ExcerptInfo>,
 706    pub next: ExcerptInfo,
 707    /// The row in the `MultiBuffer` where the boundary is located
 708    pub row: MultiBufferRow,
 709}
 710
 711impl ExcerptBoundary {
 712    pub fn starts_new_buffer(&self) -> bool {
 713        match (self.prev.as_ref(), &self.next) {
 714            (None, _) => true,
 715            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 716        }
 717    }
 718}
 719
 720#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 721pub struct ExpandInfo {
 722    pub direction: ExpandExcerptDirection,
 723    pub excerpt_id: ExcerptId,
 724}
 725
 726#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 727pub struct RowInfo {
 728    pub buffer_id: Option<BufferId>,
 729    pub buffer_row: Option<u32>,
 730    pub multibuffer_row: Option<MultiBufferRow>,
 731    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 732    pub expand_info: Option<ExpandInfo>,
 733    pub wrapped_buffer_row: Option<u32>,
 734}
 735
 736/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 737#[derive(Clone)]
 738struct Excerpt {
 739    /// The unique identifier for this excerpt
 740    id: ExcerptId,
 741    /// The location of the excerpt in the [`MultiBuffer`]
 742    locator: Locator,
 743    /// The buffer being excerpted
 744    buffer_id: BufferId,
 745    /// A snapshot of the buffer being excerpted
 746    buffer: BufferSnapshot,
 747    /// The range of the buffer to be shown in the excerpt
 748    range: ExcerptRange<text::Anchor>,
 749    /// The last row in the excerpted slice of the buffer
 750    max_buffer_row: BufferRow,
 751    /// A summary of the text in the excerpt
 752    text_summary: TextSummary,
 753    has_trailing_newline: bool,
 754}
 755
 756/// A public view into an `Excerpt` in a [`MultiBuffer`].
 757///
 758/// Contains methods for getting the [`Buffer`] of the excerpt,
 759/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 760#[derive(Clone)]
 761pub struct MultiBufferExcerpt<'a> {
 762    excerpt: &'a Excerpt,
 763    diff_transforms:
 764        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 765    /// The offset in the multibuffer considering diff transforms.
 766    offset: MultiBufferOffset,
 767    /// The offset in the multibuffer without diff transforms.
 768    excerpt_offset: ExcerptOffset,
 769    buffer_offset: BufferOffset,
 770}
 771
 772#[derive(Clone, Debug)]
 773struct ExcerptIdMapping {
 774    id: ExcerptId,
 775    locator: Locator,
 776}
 777
 778/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 779/// These ranges are relative to the buffer itself
 780#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 781pub struct ExcerptRange<T> {
 782    /// The full range of text to be shown in the excerpt.
 783    pub context: Range<T>,
 784    /// The primary range of text to be highlighted in the excerpt.
 785    /// In a multi-buffer search, this would be the text that matched the search
 786    pub primary: Range<T>,
 787}
 788
 789impl<T: Clone> ExcerptRange<T> {
 790    pub fn new(context: Range<T>) -> Self {
 791        Self {
 792            context: context.clone(),
 793            primary: context,
 794        }
 795    }
 796}
 797
 798#[derive(Clone, Debug, Default)]
 799pub struct ExcerptSummary {
 800    excerpt_id: ExcerptId,
 801    /// The location of the last [`Excerpt`] being summarized
 802    excerpt_locator: Locator,
 803    widest_line_number: u32,
 804    text: MBTextSummary,
 805}
 806
 807#[derive(Debug, Clone)]
 808pub struct DiffTransformSummary {
 809    input: MBTextSummary,
 810    output: MBTextSummary,
 811}
 812
 813/// Summary of a string of text.
 814#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 815pub struct MBTextSummary {
 816    /// Length in bytes.
 817    pub len: MultiBufferOffset,
 818    /// Length in UTF-8.
 819    pub chars: usize,
 820    /// Length in UTF-16 code units
 821    pub len_utf16: OffsetUtf16,
 822    /// A point representing the number of lines and the length of the last line.
 823    ///
 824    /// In other words, it marks the point after the last byte in the text, (if
 825    /// EOF was a character, this would be its position).
 826    pub lines: Point,
 827    /// How many `char`s are in the first line
 828    pub first_line_chars: u32,
 829    /// How many `char`s are in the last line
 830    pub last_line_chars: u32,
 831    /// How many UTF-16 code units are in the last line
 832    pub last_line_len_utf16: u32,
 833    /// The row idx of the longest row
 834    pub longest_row: u32,
 835    /// How many `char`s are in the longest row
 836    pub longest_row_chars: u32,
 837}
 838
 839impl From<TextSummary> for MBTextSummary {
 840    fn from(summary: TextSummary) -> Self {
 841        MBTextSummary {
 842            len: MultiBufferOffset(summary.len),
 843            chars: summary.chars,
 844            len_utf16: summary.len_utf16,
 845            lines: summary.lines,
 846            first_line_chars: summary.first_line_chars,
 847            last_line_chars: summary.last_line_chars,
 848            last_line_len_utf16: summary.last_line_len_utf16,
 849            longest_row: summary.longest_row,
 850            longest_row_chars: summary.longest_row_chars,
 851        }
 852    }
 853}
 854impl From<&str> for MBTextSummary {
 855    fn from(text: &str) -> Self {
 856        MBTextSummary::from(TextSummary::from(text))
 857    }
 858}
 859
 860impl MultiBufferDimension for MBTextSummary {
 861    type TextDimension = TextSummary;
 862
 863    fn from_summary(summary: &MBTextSummary) -> Self {
 864        *summary
 865    }
 866
 867    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 868        *self += *summary;
 869    }
 870
 871    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 872        *self += *summary;
 873    }
 874}
 875
 876impl AddAssign for MBTextSummary {
 877    fn add_assign(&mut self, other: MBTextSummary) {
 878        let joined_chars = self.last_line_chars + other.first_line_chars;
 879        if joined_chars > self.longest_row_chars {
 880            self.longest_row = self.lines.row;
 881            self.longest_row_chars = joined_chars;
 882        }
 883        if other.longest_row_chars > self.longest_row_chars {
 884            self.longest_row = self.lines.row + other.longest_row;
 885            self.longest_row_chars = other.longest_row_chars;
 886        }
 887
 888        if self.lines.row == 0 {
 889            self.first_line_chars += other.first_line_chars;
 890        }
 891
 892        if other.lines.row == 0 {
 893            self.last_line_chars += other.first_line_chars;
 894            self.last_line_len_utf16 += other.last_line_len_utf16;
 895        } else {
 896            self.last_line_chars = other.last_line_chars;
 897            self.last_line_len_utf16 = other.last_line_len_utf16;
 898        }
 899
 900        self.chars += other.chars;
 901        self.len += other.len;
 902        self.len_utf16 += other.len_utf16;
 903        self.lines += other.lines;
 904    }
 905}
 906
 907impl AddAssign<TextSummary> for MBTextSummary {
 908    fn add_assign(&mut self, other: TextSummary) {
 909        *self += MBTextSummary::from(other);
 910    }
 911}
 912
 913impl MBTextSummary {
 914    pub fn lines_utf16(&self) -> PointUtf16 {
 915        PointUtf16 {
 916            row: self.lines.row,
 917            column: self.last_line_len_utf16,
 918        }
 919    }
 920}
 921
 922impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 923where
 924    K: MultiBufferDimension,
 925    V: MultiBufferDimension,
 926{
 927    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 928
 929    fn from_summary(summary: &MBTextSummary) -> Self {
 930        Self {
 931            key: K::from_summary(summary),
 932            value: Some(V::from_summary(summary)),
 933        }
 934    }
 935
 936    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 937        self.key.add_text_dim(&summary.key);
 938        if let Some(value) = &mut self.value {
 939            if let Some(other_value) = summary.value.as_ref() {
 940                value.add_text_dim(other_value);
 941            }
 942        }
 943    }
 944
 945    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 946        self.key.add_mb_text_summary(summary);
 947        if let Some(value) = &mut self.value {
 948            value.add_mb_text_summary(summary);
 949        }
 950    }
 951}
 952
 953#[derive(Clone)]
 954pub struct MultiBufferRows<'a> {
 955    point: Point,
 956    is_empty: bool,
 957    is_singleton: bool,
 958    cursor: MultiBufferCursor<'a, Point, Point>,
 959}
 960
 961pub struct MultiBufferChunks<'a> {
 962    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 963    diff_transforms:
 964        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 965    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 966    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 967    buffer_chunk: Option<Chunk<'a>>,
 968    range: Range<MultiBufferOffset>,
 969    excerpt_offset_range: Range<ExcerptOffset>,
 970    excerpt_chunks: Option<ExcerptChunks<'a>>,
 971    language_aware: bool,
 972}
 973
 974pub struct ReversedMultiBufferChunks<'a> {
 975    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 976    current_chunks: Option<rope::Chunks<'a>>,
 977    start: MultiBufferOffset,
 978    offset: MultiBufferOffset,
 979}
 980
 981pub struct MultiBufferBytes<'a> {
 982    range: Range<MultiBufferOffset>,
 983    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 984    excerpt_bytes: Option<text::Bytes<'a>>,
 985    has_trailing_newline: bool,
 986    chunk: &'a [u8],
 987}
 988
 989pub struct ReversedMultiBufferBytes<'a> {
 990    range: Range<MultiBufferOffset>,
 991    chunks: ReversedMultiBufferChunks<'a>,
 992    chunk: &'a [u8],
 993}
 994
 995#[derive(Clone)]
 996struct DiffTransforms<MBD> {
 997    output_dimension: OutputDimension<MBD>,
 998    excerpt_dimension: ExcerptDimension<MBD>,
 999}
1000
1001impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1002    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1003        Self {
1004            output_dimension: OutputDimension::zero(cx),
1005            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1006                cx,
1007            ),
1008        }
1009    }
1010
1011    fn add_summary(
1012        &mut self,
1013        summary: &'a DiffTransformSummary,
1014        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1015    ) {
1016        self.output_dimension.add_summary(summary, cx);
1017        self.excerpt_dimension.add_summary(summary, cx);
1018    }
1019}
1020
1021#[derive(Clone)]
1022struct MultiBufferCursor<'a, MBD, BD> {
1023    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1024    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1025    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1026    cached_region: Option<MultiBufferRegion<'a, MBD, BD>>,
1027}
1028
1029#[derive(Clone)]
1030struct MultiBufferRegion<'a, MBD, BD> {
1031    buffer: &'a BufferSnapshot,
1032    is_main_buffer: bool,
1033    diff_hunk_status: Option<DiffHunkStatus>,
1034    excerpt: &'a Excerpt,
1035    buffer_range: Range<BD>,
1036    range: Range<MBD>,
1037    has_trailing_newline: bool,
1038}
1039
1040struct ExcerptChunks<'a> {
1041    excerpt_id: ExcerptId,
1042    content_chunks: BufferChunks<'a>,
1043    has_footer: bool,
1044}
1045
1046#[derive(Debug)]
1047struct BufferEdit {
1048    range: Range<BufferOffset>,
1049    new_text: Arc<str>,
1050    is_insertion: bool,
1051    original_indent_column: Option<u32>,
1052    excerpt_id: ExcerptId,
1053}
1054
1055#[derive(Clone, Copy, Debug, PartialEq)]
1056enum DiffChangeKind {
1057    BufferEdited,
1058    DiffUpdated { base_changed: bool },
1059    ExpandOrCollapseHunks { expand: bool },
1060}
1061
1062#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1063pub enum ExpandExcerptDirection {
1064    Up,
1065    Down,
1066    UpAndDown,
1067}
1068
1069impl ExpandExcerptDirection {
1070    pub fn should_expand_up(&self) -> bool {
1071        match self {
1072            ExpandExcerptDirection::Up => true,
1073            ExpandExcerptDirection::Down => false,
1074            ExpandExcerptDirection::UpAndDown => true,
1075        }
1076    }
1077
1078    pub fn should_expand_down(&self) -> bool {
1079        match self {
1080            ExpandExcerptDirection::Up => false,
1081            ExpandExcerptDirection::Down => true,
1082            ExpandExcerptDirection::UpAndDown => true,
1083        }
1084    }
1085}
1086
1087#[derive(Clone, Debug, PartialEq)]
1088pub struct IndentGuide {
1089    pub buffer_id: BufferId,
1090    pub start_row: MultiBufferRow,
1091    pub end_row: MultiBufferRow,
1092    pub depth: u32,
1093    pub tab_size: u32,
1094    pub settings: IndentGuideSettings,
1095}
1096
1097impl IndentGuide {
1098    pub fn indent_level(&self) -> u32 {
1099        self.depth * self.tab_size
1100    }
1101}
1102
1103impl MultiBuffer {
1104    pub fn new(capability: Capability) -> Self {
1105        Self::new_(
1106            capability,
1107            MultiBufferSnapshot {
1108                show_headers: true,
1109                show_deleted_hunks: true,
1110                ..MultiBufferSnapshot::default()
1111            },
1112        )
1113    }
1114
1115    pub fn without_headers(capability: Capability) -> Self {
1116        Self::new_(capability, Default::default())
1117    }
1118
1119    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1120        let mut this = Self::new_(
1121            buffer.read(cx).capability(),
1122            MultiBufferSnapshot {
1123                singleton: true,
1124                show_deleted_hunks: true,
1125                ..MultiBufferSnapshot::default()
1126            },
1127        );
1128        this.singleton = true;
1129        let buffer_id = buffer.read(cx).remote_id();
1130        this.push_excerpts(
1131            buffer,
1132            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1133                buffer_id,
1134            ))],
1135            cx,
1136        );
1137        this
1138    }
1139
1140    #[inline]
1141    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1142        Self {
1143            snapshot: RefCell::new(snapshot),
1144            buffers: Default::default(),
1145            diffs: HashMap::default(),
1146            subscriptions: Topic::default(),
1147            singleton: false,
1148            capability,
1149            title: None,
1150            excerpts_by_path: Default::default(),
1151            paths_by_excerpt: Default::default(),
1152            buffer_changed_since_sync: Default::default(),
1153            history: History::default(),
1154        }
1155    }
1156
1157    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1158        let mut buffers = HashMap::default();
1159        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1160        for (buffer_id, buffer_state) in self.buffers.iter() {
1161            buffer_state.buffer.update(new_cx, |buffer, _| {
1162                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1163            });
1164            buffers.insert(
1165                *buffer_id,
1166                BufferState {
1167                    buffer: buffer_state.buffer.clone(),
1168                    last_version: buffer_state.last_version.clone(),
1169                    last_non_text_state_update_count: buffer_state
1170                        .last_non_text_state_update_count
1171                        .clone(),
1172                    excerpts: buffer_state.excerpts.clone(),
1173                    _subscriptions: [
1174                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1175                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1176                    ],
1177                },
1178            );
1179        }
1180        let mut diff_bases = HashMap::default();
1181        for (buffer_id, diff) in self.diffs.iter() {
1182            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1183        }
1184        Self {
1185            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1186            buffers: buffers,
1187            excerpts_by_path: Default::default(),
1188            paths_by_excerpt: Default::default(),
1189            diffs: diff_bases,
1190            subscriptions: Default::default(),
1191            singleton: self.singleton,
1192            capability: self.capability,
1193            history: self.history.clone(),
1194            title: self.title.clone(),
1195            buffer_changed_since_sync,
1196        }
1197    }
1198
1199    pub fn set_group_interval(&mut self, group_interval: Duration) {
1200        self.history.set_group_interval(group_interval);
1201    }
1202
1203    pub fn with_title(mut self, title: String) -> Self {
1204        self.title = Some(title);
1205        self
1206    }
1207
1208    pub fn read_only(&self) -> bool {
1209        self.capability == Capability::ReadOnly
1210    }
1211
1212    /// Returns an up-to-date snapshot of the MultiBuffer.
1213    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1214        self.sync(cx);
1215        self.snapshot.borrow().clone()
1216    }
1217
1218    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1219        self.sync(cx);
1220        self.snapshot.borrow()
1221    }
1222
1223    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1224        if self.singleton {
1225            Some(self.buffers.values().next().unwrap().buffer.clone())
1226        } else {
1227            None
1228        }
1229    }
1230
1231    pub fn is_singleton(&self) -> bool {
1232        self.singleton
1233    }
1234
1235    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1236        self.subscriptions.subscribe()
1237    }
1238
1239    pub fn is_dirty(&self, cx: &App) -> bool {
1240        self.read(cx).is_dirty()
1241    }
1242
1243    pub fn has_deleted_file(&self, cx: &App) -> bool {
1244        self.read(cx).has_deleted_file()
1245    }
1246
1247    pub fn has_conflict(&self, cx: &App) -> bool {
1248        self.read(cx).has_conflict()
1249    }
1250
1251    // The `is_empty` signature doesn't match what clippy expects
1252    #[allow(clippy::len_without_is_empty)]
1253    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1254        self.read(cx).len()
1255    }
1256
1257    pub fn is_empty(&self) -> bool {
1258        self.buffers.is_empty()
1259    }
1260
1261    pub fn edit<I, S, T>(
1262        &mut self,
1263        edits: I,
1264        autoindent_mode: Option<AutoindentMode>,
1265        cx: &mut Context<Self>,
1266    ) where
1267        I: IntoIterator<Item = (Range<S>, T)>,
1268        S: ToOffset,
1269        T: Into<Arc<str>>,
1270    {
1271        if self.read_only() || self.buffers.is_empty() {
1272            return;
1273        }
1274        self.sync_mut(cx);
1275        let edits = edits
1276            .into_iter()
1277            .map(|(range, new_text)| {
1278                let mut range = range.start.to_offset(self.snapshot.get_mut())
1279                    ..range.end.to_offset(self.snapshot.get_mut());
1280                if range.start > range.end {
1281                    mem::swap(&mut range.start, &mut range.end);
1282                }
1283                (range, new_text.into())
1284            })
1285            .collect::<Vec<_>>();
1286
1287        return edit_internal(self, edits, autoindent_mode, cx);
1288
1289        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1290        fn edit_internal(
1291            this: &mut MultiBuffer,
1292            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1293            mut autoindent_mode: Option<AutoindentMode>,
1294            cx: &mut Context<MultiBuffer>,
1295        ) {
1296            let original_indent_columns = match &mut autoindent_mode {
1297                Some(AutoindentMode::Block {
1298                    original_indent_columns,
1299                }) => mem::take(original_indent_columns),
1300                _ => Default::default(),
1301            };
1302
1303            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1304                edits,
1305                this.snapshot.get_mut(),
1306                &original_indent_columns,
1307            );
1308
1309            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1310            for (buffer_id, mut edits) in buffer_edits {
1311                buffer_ids.push(buffer_id);
1312                edits.sort_by_key(|edit| edit.range.start);
1313                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1314                    let mut edits = edits.into_iter().peekable();
1315                    let mut insertions = Vec::new();
1316                    let mut original_indent_columns = Vec::new();
1317                    let mut deletions = Vec::new();
1318                    let empty_str: Arc<str> = Arc::default();
1319                    while let Some(BufferEdit {
1320                        mut range,
1321                        mut new_text,
1322                        mut is_insertion,
1323                        original_indent_column,
1324                        excerpt_id,
1325                    }) = edits.next()
1326                    {
1327                        while let Some(BufferEdit {
1328                            range: next_range,
1329                            is_insertion: next_is_insertion,
1330                            new_text: next_new_text,
1331                            excerpt_id: next_excerpt_id,
1332                            ..
1333                        }) = edits.peek()
1334                        {
1335                            if range.end >= next_range.start {
1336                                range.end = cmp::max(next_range.end, range.end);
1337                                is_insertion |= *next_is_insertion;
1338                                if excerpt_id == *next_excerpt_id {
1339                                    new_text = format!("{new_text}{next_new_text}").into();
1340                                }
1341                                edits.next();
1342                            } else {
1343                                break;
1344                            }
1345                        }
1346
1347                        if is_insertion {
1348                            original_indent_columns.push(original_indent_column);
1349                            insertions.push((
1350                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1351                                new_text.clone(),
1352                            ));
1353                        } else if !range.is_empty() {
1354                            deletions.push((
1355                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1356                                empty_str.clone(),
1357                            ));
1358                        }
1359                    }
1360
1361                    let deletion_autoindent_mode =
1362                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1363                            Some(AutoindentMode::Block {
1364                                original_indent_columns: Default::default(),
1365                            })
1366                        } else {
1367                            autoindent_mode.clone()
1368                        };
1369                    let insertion_autoindent_mode =
1370                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1371                            Some(AutoindentMode::Block {
1372                                original_indent_columns,
1373                            })
1374                        } else {
1375                            autoindent_mode.clone()
1376                        };
1377
1378                    buffer.edit(deletions, deletion_autoindent_mode, cx);
1379                    buffer.edit(insertions, insertion_autoindent_mode, cx);
1380                })
1381            }
1382
1383            cx.emit(Event::ExcerptsEdited {
1384                excerpt_ids: edited_excerpt_ids,
1385                buffer_ids,
1386            });
1387        }
1388    }
1389
1390    fn convert_edits_to_buffer_edits(
1391        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1392        snapshot: &MultiBufferSnapshot,
1393        original_indent_columns: &[Option<u32>],
1394    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1395        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1396        let mut edited_excerpt_ids = Vec::new();
1397        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1398        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1399            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1400
1401            cursor.seek(&range.start);
1402            let mut start_region = cursor.region().expect("start offset out of bounds");
1403            if !start_region.is_main_buffer {
1404                cursor.next();
1405                if let Some(region) = cursor.region() {
1406                    start_region = region;
1407                } else {
1408                    continue;
1409                }
1410            }
1411
1412            if range.end < start_region.range.start {
1413                continue;
1414            }
1415
1416            if range.end > start_region.range.end {
1417                cursor.seek_forward(&range.end);
1418            }
1419            let mut end_region = cursor.region().expect("end offset out of bounds");
1420            if !end_region.is_main_buffer {
1421                cursor.prev();
1422                if let Some(region) = cursor.region() {
1423                    end_region = region;
1424                } else {
1425                    continue;
1426                }
1427            }
1428
1429            if range.start > end_region.range.end {
1430                continue;
1431            }
1432
1433            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1434            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1435            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1436                .min(start_region.buffer_range.end);
1437            let buffer_end =
1438                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1439
1440            if start_region.excerpt.id == end_region.excerpt.id {
1441                if start_region.is_main_buffer {
1442                    edited_excerpt_ids.push(start_region.excerpt.id);
1443                    buffer_edits
1444                        .entry(start_region.buffer.remote_id())
1445                        .or_default()
1446                        .push(BufferEdit {
1447                            range: buffer_start..buffer_end,
1448                            new_text,
1449                            is_insertion: true,
1450                            original_indent_column,
1451                            excerpt_id: start_region.excerpt.id,
1452                        });
1453                }
1454            } else {
1455                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1456                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1457                if start_region.is_main_buffer {
1458                    edited_excerpt_ids.push(start_region.excerpt.id);
1459                    buffer_edits
1460                        .entry(start_region.buffer.remote_id())
1461                        .or_default()
1462                        .push(BufferEdit {
1463                            range: start_excerpt_range,
1464                            new_text: new_text.clone(),
1465                            is_insertion: true,
1466                            original_indent_column,
1467                            excerpt_id: start_region.excerpt.id,
1468                        });
1469                }
1470                if end_region.is_main_buffer {
1471                    edited_excerpt_ids.push(end_region.excerpt.id);
1472                    buffer_edits
1473                        .entry(end_region.buffer.remote_id())
1474                        .or_default()
1475                        .push(BufferEdit {
1476                            range: end_excerpt_range,
1477                            new_text: new_text.clone(),
1478                            is_insertion: false,
1479                            original_indent_column,
1480                            excerpt_id: end_region.excerpt.id,
1481                        });
1482                }
1483
1484                cursor.seek(&range.start);
1485                cursor.next_excerpt();
1486                while let Some(region) = cursor.region() {
1487                    if region.excerpt.id == end_region.excerpt.id {
1488                        break;
1489                    }
1490                    if region.is_main_buffer {
1491                        edited_excerpt_ids.push(region.excerpt.id);
1492                        buffer_edits
1493                            .entry(region.buffer.remote_id())
1494                            .or_default()
1495                            .push(BufferEdit {
1496                                range: region.buffer_range,
1497                                new_text: new_text.clone(),
1498                                is_insertion: false,
1499                                original_indent_column,
1500                                excerpt_id: region.excerpt.id,
1501                            });
1502                    }
1503                    cursor.next_excerpt();
1504                }
1505            }
1506        }
1507        (buffer_edits, edited_excerpt_ids)
1508    }
1509
1510    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1511    where
1512        I: IntoIterator<Item = Range<S>>,
1513        S: ToOffset,
1514    {
1515        if self.read_only() || self.buffers.is_empty() {
1516            return;
1517        }
1518        self.sync_mut(cx);
1519        let empty = Arc::<str>::from("");
1520        let edits = ranges
1521            .into_iter()
1522            .map(|range| {
1523                let mut range = range.start.to_offset(self.snapshot.get_mut())
1524                    ..range.end.to_offset(&self.snapshot.get_mut());
1525                if range.start > range.end {
1526                    mem::swap(&mut range.start, &mut range.end);
1527                }
1528                (range, empty.clone())
1529            })
1530            .collect::<Vec<_>>();
1531
1532        return autoindent_ranges_internal(self, edits, cx);
1533
1534        fn autoindent_ranges_internal(
1535            this: &mut MultiBuffer,
1536            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1537            cx: &mut Context<MultiBuffer>,
1538        ) {
1539            let (buffer_edits, edited_excerpt_ids) =
1540                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1541
1542            let mut buffer_ids = Vec::new();
1543            for (buffer_id, mut edits) in buffer_edits {
1544                buffer_ids.push(buffer_id);
1545                edits.sort_unstable_by_key(|edit| edit.range.start);
1546
1547                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1548                for edit in edits {
1549                    if let Some(last_range) = ranges.last_mut()
1550                        && edit.range.start <= last_range.end
1551                    {
1552                        last_range.end = last_range.end.max(edit.range.end);
1553                        continue;
1554                    }
1555                    ranges.push(edit.range);
1556                }
1557
1558                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1559                    buffer.autoindent_ranges(ranges, cx);
1560                })
1561            }
1562
1563            cx.emit(Event::ExcerptsEdited {
1564                excerpt_ids: edited_excerpt_ids,
1565                buffer_ids,
1566            });
1567        }
1568    }
1569
1570    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1571    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1572    /// Panics if the given position is invalid.
1573    pub fn insert_empty_line(
1574        &mut self,
1575        position: impl ToPoint,
1576        space_above: bool,
1577        space_below: bool,
1578        cx: &mut Context<Self>,
1579    ) -> Point {
1580        let multibuffer_point = position.to_point(&self.read(cx));
1581        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1582        self.start_transaction(cx);
1583        let empty_line_start = buffer.update(cx, |buffer, cx| {
1584            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1585        });
1586        self.end_transaction(cx);
1587        multibuffer_point + (empty_line_start - buffer_point)
1588    }
1589
1590    pub fn set_active_selections(
1591        &self,
1592        selections: &[Selection<Anchor>],
1593        line_mode: bool,
1594        cursor_shape: CursorShape,
1595        cx: &mut Context<Self>,
1596    ) {
1597        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1598            Default::default();
1599        let snapshot = self.read(cx);
1600        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1601        for selection in selections {
1602            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1603            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1604
1605            cursor.seek(&Some(start_locator), Bias::Left);
1606            while let Some(excerpt) = cursor.item()
1607                && excerpt.locator <= *end_locator
1608            {
1609                let mut start = excerpt.range.context.start;
1610                let mut end = excerpt.range.context.end;
1611                if excerpt.id == selection.start.excerpt_id {
1612                    start = selection.start.text_anchor;
1613                }
1614                if excerpt.id == selection.end.excerpt_id {
1615                    end = selection.end.text_anchor;
1616                }
1617                selections_by_buffer
1618                    .entry(excerpt.buffer_id)
1619                    .or_default()
1620                    .push(Selection {
1621                        id: selection.id,
1622                        start,
1623                        end,
1624                        reversed: selection.reversed,
1625                        goal: selection.goal,
1626                    });
1627
1628                cursor.next();
1629            }
1630        }
1631
1632        for (buffer_id, buffer_state) in self.buffers.iter() {
1633            if !selections_by_buffer.contains_key(buffer_id) {
1634                buffer_state
1635                    .buffer
1636                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1637            }
1638        }
1639
1640        for (buffer_id, mut selections) in selections_by_buffer {
1641            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1642                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1643                let mut selections = selections.into_iter().peekable();
1644                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1645                    let mut selection = selections.next()?;
1646                    while let Some(next_selection) = selections.peek() {
1647                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1648                            let next_selection = selections.next().unwrap();
1649                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1650                                selection.end = next_selection.end;
1651                            }
1652                        } else {
1653                            break;
1654                        }
1655                    }
1656                    Some(selection)
1657                }));
1658                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1659            });
1660        }
1661    }
1662
1663    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1664        for buffer in self.buffers.values() {
1665            buffer
1666                .buffer
1667                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1668        }
1669    }
1670
1671    pub fn push_excerpts<O>(
1672        &mut self,
1673        buffer: Entity<Buffer>,
1674        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1675        cx: &mut Context<Self>,
1676    ) -> Vec<ExcerptId>
1677    where
1678        O: text::ToOffset,
1679    {
1680        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1681    }
1682
1683    fn merge_excerpt_ranges<'a>(
1684        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1685    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1686        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1687        let mut counts: Vec<usize> = Vec::new();
1688        for range in expanded_ranges {
1689            if let Some(last_range) = merged_ranges.last_mut() {
1690                assert!(
1691                    last_range.context.start <= range.context.start,
1692                    "ranges must be sorted: {last_range:?} <= {range:?}"
1693                );
1694                if last_range.context.end >= range.context.start
1695                    || last_range.context.end.row + 1 == range.context.start.row
1696                {
1697                    last_range.context.end = range.context.end.max(last_range.context.end);
1698                    *counts.last_mut().unwrap() += 1;
1699                    continue;
1700                }
1701            }
1702            merged_ranges.push(range.clone());
1703            counts.push(1);
1704        }
1705        (merged_ranges, counts)
1706    }
1707
1708    pub fn insert_excerpts_after<O>(
1709        &mut self,
1710        prev_excerpt_id: ExcerptId,
1711        buffer: Entity<Buffer>,
1712        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1713        cx: &mut Context<Self>,
1714    ) -> Vec<ExcerptId>
1715    where
1716        O: text::ToOffset,
1717    {
1718        let mut ids = Vec::new();
1719        let mut next_excerpt_id =
1720            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1721                last_entry.id.0 + 1
1722            } else {
1723                1
1724            };
1725        self.insert_excerpts_with_ids_after(
1726            prev_excerpt_id,
1727            buffer,
1728            ranges.into_iter().map(|range| {
1729                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1730                ids.push(id);
1731                (id, range)
1732            }),
1733            cx,
1734        );
1735        ids
1736    }
1737
1738    pub fn insert_excerpts_with_ids_after<O>(
1739        &mut self,
1740        prev_excerpt_id: ExcerptId,
1741        buffer: Entity<Buffer>,
1742        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1743        cx: &mut Context<Self>,
1744    ) where
1745        O: text::ToOffset,
1746    {
1747        assert_eq!(self.history.transaction_depth(), 0);
1748        let mut ranges = ranges.into_iter().peekable();
1749        if ranges.peek().is_none() {
1750            return Default::default();
1751        }
1752
1753        self.sync_mut(cx);
1754
1755        let buffer_snapshot = buffer.read(cx).snapshot();
1756        let buffer_id = buffer_snapshot.remote_id();
1757
1758        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1759            self.buffer_changed_since_sync.replace(true);
1760            buffer.update(cx, |buffer, _| {
1761                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1762            });
1763            BufferState {
1764                last_version: RefCell::new(buffer_snapshot.version().clone()),
1765                last_non_text_state_update_count: Cell::new(
1766                    buffer_snapshot.non_text_state_update_count(),
1767                ),
1768                excerpts: Default::default(),
1769                _subscriptions: [
1770                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1771                    cx.subscribe(&buffer, Self::on_buffer_event),
1772                ],
1773                buffer: buffer.clone(),
1774            }
1775        });
1776
1777        let mut snapshot = self.snapshot.get_mut();
1778
1779        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1780        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1781        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1782        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1783        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1784
1785        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1786        new_excerpts.update_last(
1787            |excerpt| {
1788                excerpt.has_trailing_newline = true;
1789            },
1790            (),
1791        );
1792
1793        let next_locator = if let Some(excerpt) = cursor.item() {
1794            excerpt.locator.clone()
1795        } else {
1796            Locator::max()
1797        };
1798
1799        let mut excerpts = Vec::new();
1800        while let Some((id, range)) = ranges.next() {
1801            let locator = Locator::between(&prev_locator, &next_locator);
1802            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1803                buffer_state.excerpts.insert(ix, locator.clone());
1804            }
1805            let range = ExcerptRange {
1806                context: buffer_snapshot.anchor_before(&range.context.start)
1807                    ..buffer_snapshot.anchor_after(&range.context.end),
1808                primary: buffer_snapshot.anchor_before(&range.primary.start)
1809                    ..buffer_snapshot.anchor_after(&range.primary.end),
1810            };
1811            excerpts.push((id, range.clone()));
1812            let excerpt = Excerpt::new(
1813                id,
1814                locator.clone(),
1815                buffer_id,
1816                buffer_snapshot.clone(),
1817                range,
1818                ranges.peek().is_some() || cursor.item().is_some(),
1819            );
1820            new_excerpts.push(excerpt, ());
1821            prev_locator = locator.clone();
1822
1823            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1824                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1825            }
1826            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1827        }
1828
1829        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1830
1831        let suffix = cursor.suffix();
1832        let changed_trailing_excerpt = suffix.is_empty();
1833        new_excerpts.append(suffix, ());
1834        drop(cursor);
1835        snapshot.excerpts = new_excerpts;
1836        snapshot.excerpt_ids = new_excerpt_ids;
1837        if changed_trailing_excerpt {
1838            snapshot.trailing_excerpt_update_count += 1;
1839        }
1840
1841        let edits = Self::sync_diff_transforms(
1842            &mut snapshot,
1843            vec![Edit {
1844                old: edit_start..edit_start,
1845                new: edit_start..edit_end,
1846            }],
1847            DiffChangeKind::BufferEdited,
1848        );
1849        if !edits.is_empty() {
1850            self.subscriptions.publish(edits);
1851        }
1852
1853        cx.emit(Event::Edited {
1854            edited_buffer: None,
1855        });
1856        cx.emit(Event::ExcerptsAdded {
1857            buffer,
1858            predecessor: prev_excerpt_id,
1859            excerpts,
1860        });
1861        cx.notify();
1862    }
1863
1864    pub fn clear(&mut self, cx: &mut Context<Self>) {
1865        self.sync_mut(cx);
1866        let ids = self.excerpt_ids();
1867        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1868        self.excerpts_by_path.clear();
1869        self.paths_by_excerpt.clear();
1870        let MultiBufferSnapshot {
1871            excerpts,
1872            diffs: _,
1873            diff_transforms: _,
1874            non_text_state_update_count: _,
1875            edit_count: _,
1876            is_dirty,
1877            has_deleted_file,
1878            has_conflict,
1879            singleton: _,
1880            excerpt_ids: _,
1881            replaced_excerpts,
1882            trailing_excerpt_update_count,
1883            all_diff_hunks_expanded: _,
1884            show_deleted_hunks: _,
1885            show_headers: _,
1886        } = self.snapshot.get_mut();
1887        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1888        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1889        *excerpts = Default::default();
1890        *trailing_excerpt_update_count += 1;
1891        *is_dirty = false;
1892        *has_deleted_file = false;
1893        *has_conflict = false;
1894        replaced_excerpts.clear();
1895
1896        let edits = Self::sync_diff_transforms(
1897            self.snapshot.get_mut(),
1898            vec![Edit {
1899                old: start..prev_len,
1900                new: start..start,
1901            }],
1902            DiffChangeKind::BufferEdited,
1903        );
1904        if !edits.is_empty() {
1905            self.subscriptions.publish(edits);
1906        }
1907        cx.emit(Event::Edited {
1908            edited_buffer: None,
1909        });
1910        cx.emit(Event::ExcerptsRemoved {
1911            ids,
1912            removed_buffer_ids,
1913        });
1914        cx.notify();
1915    }
1916
1917    pub fn excerpts_for_buffer(
1918        &self,
1919        buffer_id: BufferId,
1920        cx: &App,
1921    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1922        let mut excerpts = Vec::new();
1923        let snapshot = self.read(cx);
1924        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1925        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1926            for locator in locators {
1927                cursor.seek_forward(&Some(locator), Bias::Left);
1928                if let Some(excerpt) = cursor.item()
1929                    && excerpt.locator == *locator
1930                {
1931                    excerpts.push((excerpt.id, excerpt.range.clone()));
1932                }
1933            }
1934        }
1935
1936        excerpts
1937    }
1938
1939    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1940        let snapshot = self.read(cx);
1941        let mut excerpts = snapshot
1942            .excerpts
1943            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
1944        let mut diff_transforms = snapshot
1945            .diff_transforms
1946            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1947        diff_transforms.next();
1948        let locators = self
1949            .buffers
1950            .get(&buffer_id)
1951            .into_iter()
1952            .flat_map(|state| &state.excerpts);
1953        let mut result = Vec::new();
1954        for locator in locators {
1955            excerpts.seek_forward(&Some(locator), Bias::Left);
1956            if let Some(excerpt) = excerpts.item()
1957                && excerpt.locator == *locator
1958            {
1959                let excerpt_start = excerpts.start().1;
1960                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1961
1962                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1963                let overshoot = excerpt_start - diff_transforms.start().0;
1964                let start = diff_transforms.start().1 + overshoot;
1965
1966                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1967                let overshoot = excerpt_end - diff_transforms.start().0;
1968                let end = diff_transforms.start().1 + overshoot;
1969
1970                result.push(start.0..end.0)
1971            }
1972        }
1973        result
1974    }
1975
1976    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1977        self.snapshot
1978            .borrow()
1979            .excerpts
1980            .iter()
1981            .map(|entry| entry.buffer_id)
1982            .collect()
1983    }
1984
1985    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1986        self.snapshot
1987            .borrow()
1988            .excerpts
1989            .iter()
1990            .map(|entry| entry.id)
1991            .collect()
1992    }
1993
1994    pub fn excerpt_containing(
1995        &self,
1996        position: impl ToOffset,
1997        cx: &App,
1998    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1999        let snapshot = self.read(cx);
2000        let offset = position.to_offset(&snapshot);
2001
2002        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2003        cursor.seek(&offset);
2004        cursor
2005            .excerpt()
2006            .or_else(|| snapshot.excerpts.last())
2007            .map(|excerpt| {
2008                (
2009                    excerpt.id,
2010                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2011                    excerpt.range.context.clone(),
2012                )
2013            })
2014    }
2015
2016    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2017        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2018            self.buffer(buffer_id)
2019        } else {
2020            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2021            Some(buffer)
2022        }
2023    }
2024
2025    // If point is at the end of the buffer, the last excerpt is returned
2026    pub fn point_to_buffer_offset<T: ToOffset>(
2027        &self,
2028        point: T,
2029        cx: &App,
2030    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2031        let snapshot = self.read(cx);
2032        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2033        Some((
2034            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2035            offset,
2036        ))
2037    }
2038
2039    // If point is at the end of the buffer, the last excerpt is returned
2040    pub fn point_to_buffer_point<T: ToPoint>(
2041        &self,
2042        point: T,
2043        cx: &App,
2044    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2045        let snapshot = self.read(cx);
2046        let (buffer, point, is_main_buffer) =
2047            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2048        Some((
2049            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2050            point,
2051            is_main_buffer,
2052        ))
2053    }
2054
2055    pub fn buffer_point_to_anchor(
2056        &self,
2057        buffer: &Entity<Buffer>,
2058        point: Point,
2059        cx: &App,
2060    ) -> Option<Anchor> {
2061        let mut found = None;
2062        let snapshot = buffer.read(cx).snapshot();
2063        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2064            let start = range.context.start.to_point(&snapshot);
2065            let end = range.context.end.to_point(&snapshot);
2066            if start <= point && point < end {
2067                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2068                break;
2069            }
2070            if point < start {
2071                found = Some((start, excerpt_id));
2072            }
2073            if point > end {
2074                found = Some((end, excerpt_id));
2075            }
2076        }
2077
2078        found.map(|(point, excerpt_id)| {
2079            let text_anchor = snapshot.anchor_after(point);
2080            Anchor::in_buffer(excerpt_id, text_anchor)
2081        })
2082    }
2083
2084    pub fn buffer_anchor_to_anchor(
2085        &self,
2086        buffer: &Entity<Buffer>,
2087        anchor: text::Anchor,
2088        cx: &App,
2089    ) -> Option<Anchor> {
2090        let snapshot = buffer.read(cx).snapshot();
2091        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2092            if range.context.start.cmp(&anchor, &snapshot).is_le()
2093                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2094            {
2095                return Some(Anchor::in_buffer(excerpt_id, anchor));
2096            }
2097        }
2098
2099        None
2100    }
2101
2102    pub fn remove_excerpts(
2103        &mut self,
2104        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2105        cx: &mut Context<Self>,
2106    ) {
2107        self.sync_mut(cx);
2108        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2109        if ids.is_empty() {
2110            return;
2111        }
2112        self.buffer_changed_since_sync.replace(true);
2113
2114        let mut snapshot = self.snapshot.get_mut();
2115        let mut new_excerpts = SumTree::default();
2116        let mut cursor = snapshot
2117            .excerpts
2118            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2119        let mut edits = Vec::new();
2120        let mut excerpt_ids = ids.iter().copied().peekable();
2121        let mut removed_buffer_ids = Vec::new();
2122
2123        while let Some(excerpt_id) = excerpt_ids.next() {
2124            self.paths_by_excerpt.remove(&excerpt_id);
2125            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2126            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2127            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2128
2129            if let Some(mut excerpt) = cursor.item() {
2130                if excerpt.id != excerpt_id {
2131                    continue;
2132                }
2133                let mut old_start = cursor.start().1;
2134
2135                // Skip over the removed excerpt.
2136                'remove_excerpts: loop {
2137                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2138                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2139                        if buffer_state.excerpts.is_empty() {
2140                            log::debug!(
2141                                "removing buffer and diff for buffer {}",
2142                                excerpt.buffer_id
2143                            );
2144                            self.buffers.remove(&excerpt.buffer_id);
2145                            removed_buffer_ids.push(excerpt.buffer_id);
2146                        }
2147                    }
2148                    cursor.next();
2149
2150                    // Skip over any subsequent excerpts that are also removed.
2151                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2152                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2153                        if let Some(next_excerpt) = cursor.item()
2154                            && next_excerpt.locator == *next_locator
2155                        {
2156                            excerpt_ids.next();
2157                            excerpt = next_excerpt;
2158                            continue 'remove_excerpts;
2159                        }
2160                    }
2161
2162                    break;
2163                }
2164
2165                // When removing the last excerpt, remove the trailing newline from
2166                // the previous excerpt.
2167                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2168                    old_start -= 1;
2169                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2170                }
2171
2172                // Push an edit for the removal of this run of excerpts.
2173                let old_end = cursor.start().1;
2174                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2175                edits.push(Edit {
2176                    old: old_start..old_end,
2177                    new: new_start..new_start,
2178                });
2179            }
2180        }
2181        let suffix = cursor.suffix();
2182        let changed_trailing_excerpt = suffix.is_empty();
2183        new_excerpts.append(suffix, ());
2184        drop(cursor);
2185        snapshot.excerpts = new_excerpts;
2186        for buffer_id in &removed_buffer_ids {
2187            self.diffs.remove(buffer_id);
2188            snapshot.diffs.remove(buffer_id);
2189        }
2190
2191        if changed_trailing_excerpt {
2192            snapshot.trailing_excerpt_update_count += 1;
2193        }
2194
2195        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2196        if !edits.is_empty() {
2197            self.subscriptions.publish(edits);
2198        }
2199        cx.emit(Event::Edited {
2200            edited_buffer: None,
2201        });
2202        cx.emit(Event::ExcerptsRemoved {
2203            ids,
2204            removed_buffer_ids,
2205        });
2206        cx.notify();
2207    }
2208
2209    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2210        &self,
2211        anchors: Anchors,
2212        cx: &mut Context<Self>,
2213    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2214        let mut error = None;
2215        let mut futures = Vec::new();
2216        for anchor in anchors {
2217            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2218                if let Some(buffer) = self.buffers.get(&buffer_id) {
2219                    buffer.buffer.update(cx, |buffer, _| {
2220                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2221                    });
2222                } else {
2223                    error = Some(anyhow!(
2224                        "buffer {buffer_id} is not part of this multi-buffer"
2225                    ));
2226                    break;
2227                }
2228            }
2229        }
2230        async move {
2231            if let Some(error) = error {
2232                Err(error)?;
2233            }
2234            for future in futures {
2235                future.await?;
2236            }
2237            Ok(())
2238        }
2239    }
2240
2241    pub fn text_anchor_for_position<T: ToOffset>(
2242        &self,
2243        position: T,
2244        cx: &App,
2245    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2246        let snapshot = self.read(cx);
2247        let anchor = snapshot.anchor_before(position);
2248        let buffer = self
2249            .buffers
2250            .get(&anchor.text_anchor.buffer_id?)?
2251            .buffer
2252            .clone();
2253        Some((buffer, anchor.text_anchor))
2254    }
2255
2256    fn on_buffer_event(
2257        &mut self,
2258        buffer: Entity<Buffer>,
2259        event: &language::BufferEvent,
2260        cx: &mut Context<Self>,
2261    ) {
2262        use language::BufferEvent;
2263        cx.emit(match event {
2264            BufferEvent::Edited => Event::Edited {
2265                edited_buffer: Some(buffer),
2266            },
2267            BufferEvent::DirtyChanged => Event::DirtyChanged,
2268            BufferEvent::Saved => Event::Saved,
2269            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2270            BufferEvent::Reloaded => Event::Reloaded,
2271            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2272            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2273            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2274            BufferEvent::CapabilityChanged => {
2275                self.capability = buffer.read(cx).capability();
2276                return;
2277            }
2278            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2279        });
2280    }
2281
2282    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2283        let diff = diff.read(cx);
2284        let buffer_id = diff.buffer_id;
2285        let diff = DiffStateSnapshot {
2286            diff: diff.snapshot(cx),
2287            main_buffer: None,
2288        };
2289        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2290    }
2291
2292    fn inverted_buffer_diff_language_changed(
2293        &mut self,
2294        base_text_buffer_id: BufferId,
2295        diff: Entity<BufferDiff>,
2296        main_buffer: WeakEntity<Buffer>,
2297        cx: &mut Context<Self>,
2298    ) {
2299        let diff = diff.read(cx);
2300        let diff = DiffStateSnapshot {
2301            diff: diff.snapshot(cx),
2302            main_buffer: main_buffer
2303                .update(cx, |main_buffer, _| main_buffer.snapshot())
2304                .ok(),
2305        };
2306        self.snapshot
2307            .get_mut()
2308            .diffs
2309            .insert(base_text_buffer_id, diff);
2310    }
2311
2312    fn buffer_diff_changed(
2313        &mut self,
2314        diff: Entity<BufferDiff>,
2315        range: Range<text::Anchor>,
2316        cx: &mut Context<Self>,
2317    ) {
2318        self.sync_mut(cx);
2319
2320        let diff = diff.read(cx);
2321        let buffer_id = diff.buffer_id;
2322        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2323            return;
2324        };
2325        self.buffer_changed_since_sync.replace(true);
2326
2327        let buffer = buffer_state.buffer.read(cx);
2328        let diff_change_range = range.to_offset(buffer);
2329
2330        let new_diff = DiffStateSnapshot {
2331            diff: diff.snapshot(cx),
2332            main_buffer: None,
2333        };
2334        let mut snapshot = self.snapshot.get_mut();
2335        let base_text_changed = snapshot
2336            .diffs
2337            .get(&buffer_id)
2338            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2339
2340        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2341
2342        let mut excerpt_edits = Vec::new();
2343        for locator in &buffer_state.excerpts {
2344            let mut cursor = snapshot
2345                .excerpts
2346                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2347            cursor.seek_forward(&Some(locator), Bias::Left);
2348            if let Some(excerpt) = cursor.item()
2349                && excerpt.locator == *locator
2350            {
2351                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2352                if diff_change_range.end < excerpt_buffer_range.start
2353                    || diff_change_range.start > excerpt_buffer_range.end
2354                {
2355                    continue;
2356                }
2357                let excerpt_start = cursor.start().1;
2358                let excerpt_len = excerpt.text_summary.len;
2359                let diff_change_start_in_excerpt = diff_change_range
2360                    .start
2361                    .saturating_sub(excerpt_buffer_range.start);
2362                let diff_change_end_in_excerpt = diff_change_range
2363                    .end
2364                    .saturating_sub(excerpt_buffer_range.start);
2365                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2366                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2367                excerpt_edits.push(Edit {
2368                    old: edit_start..edit_end,
2369                    new: edit_start..edit_end,
2370                });
2371            }
2372        }
2373
2374        let edits = Self::sync_diff_transforms(
2375            &mut snapshot,
2376            excerpt_edits,
2377            DiffChangeKind::DiffUpdated {
2378                base_changed: base_text_changed,
2379            },
2380        );
2381        if !edits.is_empty() {
2382            self.subscriptions.publish(edits);
2383        }
2384        cx.emit(Event::Edited {
2385            edited_buffer: None,
2386        });
2387    }
2388
2389    fn inverted_buffer_diff_changed(
2390        &mut self,
2391        diff: Entity<BufferDiff>,
2392        diff_change_range: Range<usize>,
2393        base_text_buffer_id: BufferId,
2394        main_buffer: WeakEntity<Buffer>,
2395        cx: &mut Context<Self>,
2396    ) {
2397        self.sync_mut(cx);
2398
2399        let diff = diff.read(cx);
2400        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2401            return;
2402        };
2403        self.buffer_changed_since_sync.replace(true);
2404
2405        let new_diff = DiffStateSnapshot {
2406            diff: diff.snapshot(cx),
2407            main_buffer: main_buffer
2408                .update(cx, |main_buffer, _| main_buffer.snapshot())
2409                .ok(),
2410        };
2411        let mut snapshot = self.snapshot.get_mut();
2412        let base_text_changed = snapshot
2413            .diffs
2414            .get(&base_text_buffer_id)
2415            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2416
2417        snapshot
2418            .diffs
2419            .insert_or_replace(base_text_buffer_id, new_diff);
2420
2421        let mut excerpt_edits = Vec::new();
2422        for locator in &buffer_state.excerpts {
2423            let mut cursor = snapshot
2424                .excerpts
2425                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2426            cursor.seek_forward(&Some(locator), Bias::Left);
2427            if let Some(excerpt) = cursor.item()
2428                && excerpt.locator == *locator
2429            {
2430                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2431                if diff_change_range.end < excerpt_buffer_range.start
2432                    || diff_change_range.start > excerpt_buffer_range.end
2433                {
2434                    continue;
2435                }
2436                let excerpt_start = cursor.start().1;
2437                let excerpt_len = excerpt.text_summary.len;
2438                let diff_change_start_in_excerpt = diff_change_range
2439                    .start
2440                    .saturating_sub(excerpt_buffer_range.start);
2441                let diff_change_end_in_excerpt = diff_change_range
2442                    .end
2443                    .saturating_sub(excerpt_buffer_range.start);
2444                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2445                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2446                excerpt_edits.push(Edit {
2447                    old: edit_start..edit_end,
2448                    new: edit_start..edit_end,
2449                });
2450            }
2451        }
2452
2453        let edits = Self::sync_diff_transforms(
2454            &mut snapshot,
2455            excerpt_edits,
2456            DiffChangeKind::DiffUpdated {
2457                base_changed: base_text_changed,
2458            },
2459        );
2460        if !edits.is_empty() {
2461            self.subscriptions.publish(edits);
2462        }
2463        cx.emit(Event::Edited {
2464            edited_buffer: None,
2465        });
2466    }
2467
2468    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2469        self.buffers.values().map(|state| state.buffer.clone())
2470    }
2471
2472    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2473        self.all_buffers_iter().collect()
2474    }
2475
2476    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2477        self.buffers.keys().copied()
2478    }
2479
2480    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2481        self.all_buffer_ids_iter().collect()
2482    }
2483
2484    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2485        self.buffers
2486            .get(&buffer_id)
2487            .map(|state| state.buffer.clone())
2488    }
2489
2490    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2491        self.point_to_buffer_offset(point, cx)
2492            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2493    }
2494
2495    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2496        let buffer_id = self
2497            .snapshot
2498            .borrow()
2499            .excerpts
2500            .first()
2501            .map(|excerpt| excerpt.buffer.remote_id());
2502        buffer_id
2503            .and_then(|buffer_id| self.buffer(buffer_id))
2504            .map(|buffer| {
2505                let buffer = buffer.read(cx);
2506                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2507            })
2508            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2509    }
2510
2511    pub fn language_settings_at<'a, T: ToOffset>(
2512        &'a self,
2513        point: T,
2514        cx: &'a App,
2515    ) -> Cow<'a, LanguageSettings> {
2516        let mut language = None;
2517        let mut file = None;
2518        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2519            let buffer = buffer.read(cx);
2520            language = buffer.language_at(offset);
2521            file = buffer.file();
2522        }
2523        language_settings(language.map(|l| l.name()), file, cx)
2524    }
2525
2526    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2527        self.buffers.values().for_each(|state| f(&state.buffer))
2528    }
2529
2530    pub fn explicit_title(&self) -> Option<&str> {
2531        self.title.as_deref()
2532    }
2533
2534    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2535        if let Some(title) = self.title.as_ref() {
2536            return title.into();
2537        }
2538
2539        if let Some(buffer) = self.as_singleton() {
2540            let buffer = buffer.read(cx);
2541
2542            if let Some(file) = buffer.file() {
2543                return file.file_name(cx).into();
2544            }
2545
2546            if let Some(title) = self.buffer_content_title(buffer) {
2547                return title;
2548            }
2549        };
2550
2551        "untitled".into()
2552    }
2553
2554    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2555        let mut is_leading_whitespace = true;
2556        let mut count = 0;
2557        let mut prev_was_space = false;
2558        let mut title = String::new();
2559
2560        for ch in buffer.snapshot().chars() {
2561            if is_leading_whitespace && ch.is_whitespace() {
2562                continue;
2563            }
2564
2565            is_leading_whitespace = false;
2566
2567            if ch == '\n' || count >= 40 {
2568                break;
2569            }
2570
2571            if ch.is_whitespace() {
2572                if !prev_was_space {
2573                    title.push(' ');
2574                    count += 1;
2575                    prev_was_space = true;
2576                }
2577            } else {
2578                title.push(ch);
2579                count += 1;
2580                prev_was_space = false;
2581            }
2582        }
2583
2584        let title = title.trim_end().to_string();
2585
2586        if title.is_empty() {
2587            return None;
2588        }
2589
2590        Some(title.into())
2591    }
2592
2593    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2594        self.title = Some(title);
2595        cx.notify();
2596    }
2597
2598    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2599    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2600        for buffer_state in self.buffers.values() {
2601            buffer_state
2602                .buffer
2603                .update(cx, |buffer, _cx| buffer.refresh_preview());
2604        }
2605    }
2606
2607    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2608    pub fn preserve_preview(&self, cx: &App) -> bool {
2609        self.buffers
2610            .values()
2611            .all(|state| state.buffer.read(cx).preserve_preview())
2612    }
2613
2614    #[cfg(any(test, feature = "test-support"))]
2615    pub fn is_parsing(&self, cx: &App) -> bool {
2616        self.as_singleton().unwrap().read(cx).is_parsing()
2617    }
2618
2619    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2620        debug_assert!(self.diffs.values().all(|diff| diff.main_buffer.is_none()));
2621
2622        let buffer_id = diff.read(cx).buffer_id;
2623        self.buffer_diff_changed(
2624            diff.clone(),
2625            text::Anchor::min_max_range_for_buffer(buffer_id),
2626            cx,
2627        );
2628        self.diffs
2629            .insert(buffer_id, DiffState::new(diff.clone(), cx));
2630    }
2631
2632    pub fn add_inverted_diff(
2633        &mut self,
2634        base_text_buffer_id: BufferId,
2635        diff: Entity<BufferDiff>,
2636        main_buffer: Entity<Buffer>,
2637        cx: &mut Context<Self>,
2638    ) {
2639        debug_assert!(self.diffs.values().all(|diff| diff.main_buffer.is_some()));
2640
2641        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2642        self.inverted_buffer_diff_changed(
2643            diff.clone(),
2644            diff_change_range,
2645            base_text_buffer_id,
2646            main_buffer.downgrade(),
2647            cx,
2648        );
2649        self.diffs.insert(
2650            base_text_buffer_id,
2651            DiffState::new_inverted(diff, base_text_buffer_id, main_buffer, cx),
2652        );
2653    }
2654
2655    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2656        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2657    }
2658
2659    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2660        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2661    }
2662
2663    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2664        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2665    }
2666
2667    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2668        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2669        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2670    }
2671
2672    pub fn all_diff_hunks_expanded(&self) -> bool {
2673        self.snapshot.borrow().all_diff_hunks_expanded
2674    }
2675
2676    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2677        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2678        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2679    }
2680
2681    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2682        self.snapshot.get_mut().show_deleted_hunks = show;
2683        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2684    }
2685
2686    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2687        self.read(cx)
2688            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2689            .nth(1)
2690            .is_some()
2691    }
2692
2693    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2694        let snapshot = self.read(cx);
2695        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2696        let offset_range = range.to_offset(&snapshot);
2697        cursor.seek(&offset_range.start, Bias::Left);
2698        while let Some(item) = cursor.item() {
2699            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2700                break;
2701            }
2702            if item.hunk_info().is_some() {
2703                return true;
2704            }
2705            cursor.next();
2706        }
2707        false
2708    }
2709
2710    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2711        let snapshot = self.read(cx);
2712        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2713        for range in ranges {
2714            let range = range.to_point(&snapshot);
2715            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2716            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2717            let start = start.saturating_sub_usize(1);
2718            let end = snapshot.len().min(end + 1usize);
2719            cursor.seek(&start, Bias::Right);
2720            while let Some(item) = cursor.item() {
2721                if *cursor.start() >= end {
2722                    break;
2723                }
2724                if item.hunk_info().is_some() {
2725                    return true;
2726                }
2727                cursor.next();
2728            }
2729        }
2730        false
2731    }
2732
2733    pub fn expand_or_collapse_diff_hunks_inner(
2734        &mut self,
2735        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2736        expand: bool,
2737        cx: &mut Context<Self>,
2738    ) {
2739        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2740            return;
2741        }
2742        self.sync_mut(cx);
2743        let mut snapshot = self.snapshot.get_mut();
2744        let mut excerpt_edits = Vec::new();
2745        let mut last_hunk_row = None;
2746        for (range, end_excerpt_id) in ranges {
2747            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2748                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2749                    continue;
2750                }
2751                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2752                    continue;
2753                }
2754                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2755                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2756                let start = snapshot.excerpt_offset_for_anchor(&start);
2757                let end = snapshot.excerpt_offset_for_anchor(&end);
2758                last_hunk_row = Some(diff_hunk.row_range.start);
2759                excerpt_edits.push(text::Edit {
2760                    old: start..end,
2761                    new: start..end,
2762                });
2763            }
2764        }
2765
2766        let edits = Self::sync_diff_transforms(
2767            &mut snapshot,
2768            excerpt_edits,
2769            DiffChangeKind::ExpandOrCollapseHunks { expand },
2770        );
2771        if !edits.is_empty() {
2772            self.subscriptions.publish(edits);
2773        }
2774        cx.emit(Event::DiffHunksToggled);
2775        cx.emit(Event::Edited {
2776            edited_buffer: None,
2777        });
2778    }
2779
2780    pub fn expand_or_collapse_diff_hunks(
2781        &mut self,
2782        ranges: Vec<Range<Anchor>>,
2783        expand: bool,
2784        cx: &mut Context<Self>,
2785    ) {
2786        let snapshot = self.snapshot.borrow().clone();
2787        let ranges = ranges.iter().map(move |range| {
2788            let end_excerpt_id = range.end.excerpt_id;
2789            let range = range.to_point(&snapshot);
2790            let mut peek_end = range.end;
2791            if range.end.row < snapshot.max_row().0 {
2792                peek_end = Point::new(range.end.row + 1, 0);
2793            };
2794            (range.start..peek_end, end_excerpt_id)
2795        });
2796        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2797    }
2798
2799    pub fn resize_excerpt(
2800        &mut self,
2801        id: ExcerptId,
2802        range: Range<text::Anchor>,
2803        cx: &mut Context<Self>,
2804    ) {
2805        self.sync_mut(cx);
2806
2807        let mut snapshot = self.snapshot.get_mut();
2808        let locator = snapshot.excerpt_locator_for_id(id);
2809        let mut new_excerpts = SumTree::default();
2810        let mut cursor = snapshot
2811            .excerpts
2812            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2813        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2814
2815        let prefix = cursor.slice(&Some(locator), Bias::Left);
2816        new_excerpts.append(prefix, ());
2817
2818        let mut excerpt = cursor.item().unwrap().clone();
2819        let old_text_len = excerpt.text_summary.len;
2820
2821        excerpt.range.context.start = range.start;
2822        excerpt.range.context.end = range.end;
2823        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2824
2825        excerpt.text_summary = excerpt
2826            .buffer
2827            .text_summary_for_range(excerpt.range.context.clone());
2828
2829        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2830        let old_start_offset = cursor.start().1;
2831        let new_text_len = excerpt.text_summary.len;
2832        let edit = Edit {
2833            old: old_start_offset..old_start_offset + old_text_len,
2834            new: new_start_offset..new_start_offset + new_text_len,
2835        };
2836
2837        if let Some(last_edit) = edits.last_mut() {
2838            if last_edit.old.end == edit.old.start {
2839                last_edit.old.end = edit.old.end;
2840                last_edit.new.end = edit.new.end;
2841            } else {
2842                edits.push(edit);
2843            }
2844        } else {
2845            edits.push(edit);
2846        }
2847
2848        new_excerpts.push(excerpt, ());
2849
2850        cursor.next();
2851
2852        new_excerpts.append(cursor.suffix(), ());
2853
2854        drop(cursor);
2855        snapshot.excerpts = new_excerpts;
2856
2857        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2858        if !edits.is_empty() {
2859            self.subscriptions.publish(edits);
2860        }
2861        cx.emit(Event::Edited {
2862            edited_buffer: None,
2863        });
2864        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2865        cx.notify();
2866    }
2867
2868    pub fn expand_excerpts(
2869        &mut self,
2870        ids: impl IntoIterator<Item = ExcerptId>,
2871        line_count: u32,
2872        direction: ExpandExcerptDirection,
2873        cx: &mut Context<Self>,
2874    ) {
2875        if line_count == 0 {
2876            return;
2877        }
2878        self.sync_mut(cx);
2879        if !self.excerpts_by_path.is_empty() {
2880            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2881            return;
2882        }
2883        let mut snapshot = self.snapshot.get_mut();
2884
2885        let ids = ids.into_iter().collect::<Vec<_>>();
2886        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2887        let mut new_excerpts = SumTree::default();
2888        let mut cursor = snapshot
2889            .excerpts
2890            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2891        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2892
2893        for locator in &locators {
2894            let prefix = cursor.slice(&Some(locator), Bias::Left);
2895            new_excerpts.append(prefix, ());
2896
2897            let mut excerpt = cursor.item().unwrap().clone();
2898            let old_text_len = excerpt.text_summary.len;
2899
2900            let up_line_count = if direction.should_expand_up() {
2901                line_count
2902            } else {
2903                0
2904            };
2905
2906            let start_row = excerpt
2907                .range
2908                .context
2909                .start
2910                .to_point(&excerpt.buffer)
2911                .row
2912                .saturating_sub(up_line_count);
2913            let start_point = Point::new(start_row, 0);
2914            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2915
2916            let down_line_count = if direction.should_expand_down() {
2917                line_count
2918            } else {
2919                0
2920            };
2921
2922            let mut end_point = excerpt.buffer.clip_point(
2923                excerpt.range.context.end.to_point(&excerpt.buffer)
2924                    + Point::new(down_line_count, 0),
2925                Bias::Left,
2926            );
2927            end_point.column = excerpt.buffer.line_len(end_point.row);
2928            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2929            excerpt.max_buffer_row = end_point.row;
2930
2931            excerpt.text_summary = excerpt
2932                .buffer
2933                .text_summary_for_range(excerpt.range.context.clone());
2934
2935            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2936            let old_start_offset = cursor.start().1;
2937            let new_text_len = excerpt.text_summary.len;
2938            let edit = Edit {
2939                old: old_start_offset..old_start_offset + old_text_len,
2940                new: new_start_offset..new_start_offset + new_text_len,
2941            };
2942
2943            if let Some(last_edit) = edits.last_mut() {
2944                if last_edit.old.end == edit.old.start {
2945                    last_edit.old.end = edit.old.end;
2946                    last_edit.new.end = edit.new.end;
2947                } else {
2948                    edits.push(edit);
2949                }
2950            } else {
2951                edits.push(edit);
2952            }
2953
2954            new_excerpts.push(excerpt, ());
2955
2956            cursor.next();
2957        }
2958
2959        new_excerpts.append(cursor.suffix(), ());
2960
2961        drop(cursor);
2962        snapshot.excerpts = new_excerpts;
2963
2964        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2965        if !edits.is_empty() {
2966            self.subscriptions.publish(edits);
2967        }
2968        cx.emit(Event::Edited {
2969            edited_buffer: None,
2970        });
2971        cx.emit(Event::ExcerptsExpanded { ids });
2972        cx.notify();
2973    }
2974
2975    fn sync(&self, cx: &App) {
2976        let changed = self.buffer_changed_since_sync.replace(false);
2977        if !changed {
2978            return;
2979        }
2980        let edits = Self::sync_(
2981            &mut self.snapshot.borrow_mut(),
2982            &self.buffers,
2983            &self.diffs,
2984            cx,
2985        );
2986        if !edits.is_empty() {
2987            self.subscriptions.publish(edits);
2988        }
2989    }
2990
2991    fn sync_mut(&mut self, cx: &App) {
2992        let changed = self.buffer_changed_since_sync.replace(false);
2993        if !changed {
2994            return;
2995        }
2996        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2997
2998        if !edits.is_empty() {
2999            self.subscriptions.publish(edits);
3000        }
3001    }
3002
3003    fn sync_(
3004        snapshot: &mut MultiBufferSnapshot,
3005        buffers: &HashMap<BufferId, BufferState>,
3006        diffs: &HashMap<BufferId, DiffState>,
3007        cx: &App,
3008    ) -> Vec<Edit<MultiBufferOffset>> {
3009        let MultiBufferSnapshot {
3010            excerpts,
3011            diffs: buffer_diff,
3012            diff_transforms: _,
3013            non_text_state_update_count,
3014            edit_count,
3015            is_dirty,
3016            has_deleted_file,
3017            has_conflict,
3018            singleton: _,
3019            excerpt_ids: _,
3020            replaced_excerpts: _,
3021            trailing_excerpt_update_count: _,
3022            all_diff_hunks_expanded: _,
3023            show_deleted_hunks: _,
3024            show_headers: _,
3025        } = snapshot;
3026        *is_dirty = false;
3027        *has_deleted_file = false;
3028        *has_conflict = false;
3029
3030        let mut excerpts_to_edit = Vec::new();
3031        let mut non_text_state_updated = false;
3032        let mut edited = false;
3033        for buffer_state in buffers.values() {
3034            let buffer = buffer_state.buffer.read(cx);
3035            let version = buffer.version();
3036            let non_text_state_update_count = buffer.non_text_state_update_count();
3037
3038            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3039            let buffer_non_text_state_updated =
3040                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3041            if buffer_edited || buffer_non_text_state_updated {
3042                *buffer_state.last_version.borrow_mut() = version;
3043                buffer_state
3044                    .last_non_text_state_update_count
3045                    .set(non_text_state_update_count);
3046                excerpts_to_edit.extend(
3047                    buffer_state
3048                        .excerpts
3049                        .iter()
3050                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3051                );
3052            }
3053
3054            edited |= buffer_edited;
3055            non_text_state_updated |= buffer_non_text_state_updated;
3056            *is_dirty |= buffer.is_dirty();
3057            *has_deleted_file |= buffer
3058                .file()
3059                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3060            *has_conflict |= buffer.has_conflict();
3061        }
3062        if edited {
3063            *edit_count += 1;
3064        }
3065        if non_text_state_updated {
3066            *non_text_state_update_count += 1;
3067        }
3068
3069        for (id, diff) in diffs.iter() {
3070            if buffer_diff.get(id).is_none() {
3071                buffer_diff.insert(*id, diff.snapshot(cx));
3072            }
3073        }
3074
3075        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3076
3077        let mut edits = Vec::new();
3078        let mut new_excerpts = SumTree::default();
3079        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3080
3081        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3082            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3083            let old_excerpt = cursor.item().unwrap();
3084            let buffer = buffer.read(cx);
3085            let buffer_id = buffer.remote_id();
3086
3087            let mut new_excerpt;
3088            if buffer_edited {
3089                edits.extend(
3090                    buffer
3091                        .edits_since_in_range::<usize>(
3092                            old_excerpt.buffer.version(),
3093                            old_excerpt.range.context.clone(),
3094                        )
3095                        .map(|edit| {
3096                            let excerpt_old_start = cursor.start().1;
3097                            let excerpt_new_start =
3098                                ExcerptDimension(new_excerpts.summary().text.len);
3099                            let old_start = excerpt_old_start + edit.old.start;
3100                            let old_end = excerpt_old_start + edit.old.end;
3101                            let new_start = excerpt_new_start + edit.new.start;
3102                            let new_end = excerpt_new_start + edit.new.end;
3103                            Edit {
3104                                old: old_start..old_end,
3105                                new: new_start..new_end,
3106                            }
3107                        }),
3108                );
3109
3110                new_excerpt = Excerpt::new(
3111                    old_excerpt.id,
3112                    locator.clone(),
3113                    buffer_id,
3114                    buffer.snapshot(),
3115                    old_excerpt.range.clone(),
3116                    old_excerpt.has_trailing_newline,
3117                );
3118            } else {
3119                new_excerpt = old_excerpt.clone();
3120                new_excerpt.buffer = buffer.snapshot();
3121            }
3122
3123            new_excerpts.push(new_excerpt, ());
3124            cursor.next();
3125        }
3126        new_excerpts.append(cursor.suffix(), ());
3127
3128        drop(cursor);
3129        *excerpts = new_excerpts;
3130        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3131    }
3132
3133    fn sync_diff_transforms(
3134        snapshot: &mut MultiBufferSnapshot,
3135        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3136        change_kind: DiffChangeKind,
3137    ) -> Vec<Edit<MultiBufferOffset>> {
3138        if excerpt_edits.is_empty() {
3139            return vec![];
3140        }
3141
3142        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3143        let mut old_diff_transforms = snapshot
3144            .diff_transforms
3145            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3146        let mut new_diff_transforms = SumTree::default();
3147        let mut old_expanded_hunks = HashSet::default();
3148        let mut output_edits = Vec::new();
3149        let mut output_delta = 0_isize;
3150        let mut at_transform_boundary = true;
3151        let mut end_of_current_insert = None;
3152
3153        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3154        while let Some(edit) = excerpt_edits.next() {
3155            excerpts.seek_forward(&edit.new.start, Bias::Right);
3156            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3157                excerpts.prev();
3158            }
3159
3160            // Keep any transforms that are before the edit.
3161            if at_transform_boundary {
3162                at_transform_boundary = false;
3163                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3164                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3165                if let Some(transform) = old_diff_transforms.item()
3166                    && old_diff_transforms.end().0 == edit.old.start
3167                    && old_diff_transforms.start().0 < edit.old.start
3168                {
3169                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3170                    old_diff_transforms.next();
3171                }
3172            }
3173
3174            // Compute the start of the edit in output coordinates.
3175            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3176            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3177            let edit_new_start =
3178                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3179
3180            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3181                &edit,
3182                &mut excerpts,
3183                &mut old_diff_transforms,
3184                &mut new_diff_transforms,
3185                &mut end_of_current_insert,
3186                &mut old_expanded_hunks,
3187                snapshot,
3188                change_kind,
3189            );
3190
3191            // Compute the end of the edit in output coordinates.
3192            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3193            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3194            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3195            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3196            let output_edit = Edit {
3197                old: edit_old_start..edit_old_end,
3198                new: edit_new_start..edit_new_end,
3199            };
3200
3201            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3202            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3203            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3204                output_edits.push(output_edit);
3205            }
3206
3207            // If this is the last edit that intersects the current diff transform,
3208            // then recreate the content up to the end of this transform, to prepare
3209            // for reusing additional slices of the old transforms.
3210            if excerpt_edits
3211                .peek()
3212                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3213            {
3214                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3215                    && match old_diff_transforms.item() {
3216                        Some(DiffTransform::BufferContent {
3217                            inserted_hunk_info: Some(hunk),
3218                            ..
3219                        }) => excerpts.item().is_some_and(|excerpt| {
3220                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3221                        }),
3222                        _ => true,
3223                    };
3224
3225                let mut excerpt_offset = edit.new.end;
3226                if !keep_next_old_transform {
3227                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3228                    old_diff_transforms.next();
3229                }
3230
3231                old_expanded_hunks.clear();
3232                Self::push_buffer_content_transform(
3233                    snapshot,
3234                    &mut new_diff_transforms,
3235                    excerpt_offset,
3236                    end_of_current_insert,
3237                );
3238                at_transform_boundary = true;
3239            }
3240        }
3241
3242        // Keep any transforms that are after the last edit.
3243        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3244
3245        // Ensure there's always at least one buffer content transform.
3246        if new_diff_transforms.is_empty() {
3247            new_diff_transforms.push(
3248                DiffTransform::BufferContent {
3249                    summary: Default::default(),
3250                    inserted_hunk_info: None,
3251                },
3252                (),
3253            );
3254        }
3255
3256        drop(old_diff_transforms);
3257        drop(excerpts);
3258        snapshot.diff_transforms = new_diff_transforms;
3259        snapshot.edit_count += 1;
3260
3261        #[cfg(any(test, feature = "test-support"))]
3262        snapshot.check_invariants();
3263        output_edits
3264    }
3265
3266    fn recompute_diff_transforms_for_edit(
3267        edit: &Edit<ExcerptOffset>,
3268        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3269        old_diff_transforms: &mut Cursor<
3270            DiffTransform,
3271            Dimensions<ExcerptOffset, MultiBufferOffset>,
3272        >,
3273        new_diff_transforms: &mut SumTree<DiffTransform>,
3274        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3275        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3276        snapshot: &MultiBufferSnapshot,
3277        change_kind: DiffChangeKind,
3278    ) -> bool {
3279        log::trace!(
3280            "recomputing diff transform for edit {:?} => {:?}",
3281            edit.old.start..edit.old.end,
3282            edit.new.start..edit.new.end
3283        );
3284
3285        // Record which hunks were previously expanded.
3286        while let Some(item) = old_diff_transforms.item() {
3287            if let Some(hunk_info) = item.hunk_info() {
3288                log::trace!(
3289                    "previously expanded hunk at {:?}",
3290                    old_diff_transforms.start()
3291                );
3292                old_expanded_hunks.insert(hunk_info);
3293            }
3294            if old_diff_transforms.end().0 > edit.old.end {
3295                break;
3296            }
3297            old_diff_transforms.next();
3298        }
3299
3300        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3301        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3302        if old_expanded_hunks.is_empty()
3303            && change_kind == DiffChangeKind::BufferEdited
3304            && !all_diff_hunks_expanded
3305        {
3306            return false;
3307        }
3308
3309        // Visit each excerpt that intersects the edit.
3310        let mut did_expand_hunks = false;
3311        while let Some(excerpt) = excerpts.item() {
3312            // Recompute the expanded hunks in the portion of the excerpt that
3313            // intersects the edit.
3314            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3315                let buffer = &excerpt.buffer;
3316                let excerpt_start = *excerpts.start();
3317                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3318                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3319                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3320                let edit_buffer_start =
3321                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3322                let edit_buffer_end =
3323                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3324                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3325
3326                if let Some(main_buffer) = &diff.main_buffer {
3327                    for hunk in diff.hunks_intersecting_base_text_range(
3328                        edit_buffer_start..edit_buffer_end,
3329                        main_buffer,
3330                    ) {
3331                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3332                        if hunk_buffer_range.start < excerpt_buffer_start {
3333                            log::trace!("skipping hunk that starts before excerpt");
3334                            continue;
3335                        }
3336                        let hunk_excerpt_start = excerpt_start
3337                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3338                        let hunk_excerpt_end = excerpt_end
3339                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3340                        Self::push_buffer_content_transform(
3341                            snapshot,
3342                            new_diff_transforms,
3343                            hunk_excerpt_start,
3344                            *end_of_current_insert,
3345                        );
3346                        // FIXME record that the status for this region should be "deleted"
3347                        if !hunk_buffer_range.is_empty() {
3348                            let hunk_info = DiffTransformHunkInfo {
3349                                excerpt_id: excerpt.id,
3350                                hunk_start_anchor: hunk.buffer_range.start,
3351                                hunk_secondary_status: hunk.secondary_status,
3352                                is_logically_deleted: true,
3353                            };
3354                            *end_of_current_insert =
3355                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3356                        }
3357                    }
3358                } else {
3359                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3360                        ..buffer.anchor_after(edit_buffer_end);
3361                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3362                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3363                            continue;
3364                        }
3365
3366                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3367                        if hunk_buffer_range.start < excerpt_buffer_start {
3368                            log::trace!("skipping hunk that starts before excerpt");
3369                            continue;
3370                        }
3371
3372                        let hunk_info = DiffTransformHunkInfo {
3373                            excerpt_id: excerpt.id,
3374                            hunk_start_anchor: hunk.buffer_range.start,
3375                            hunk_secondary_status: hunk.secondary_status,
3376                            is_logically_deleted: false,
3377                        };
3378
3379                        let hunk_excerpt_start = excerpt_start
3380                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3381                        let hunk_excerpt_end = excerpt_end
3382                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3383
3384                        Self::push_buffer_content_transform(
3385                            snapshot,
3386                            new_diff_transforms,
3387                            hunk_excerpt_start,
3388                            *end_of_current_insert,
3389                        );
3390
3391                        // For every existing hunk, determine if it was previously expanded
3392                        // and if it should currently be expanded.
3393                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3394                        let should_expand_hunk = match &change_kind {
3395                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3396                                was_previously_expanded || all_diff_hunks_expanded
3397                            }
3398                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3399                                let intersects = hunk_buffer_range.is_empty()
3400                                    || hunk_buffer_range.end > edit_buffer_start;
3401                                if *expand {
3402                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3403                                } else {
3404                                    !intersects
3405                                        && (was_previously_expanded || all_diff_hunks_expanded)
3406                                }
3407                            }
3408                            _ => was_previously_expanded || all_diff_hunks_expanded,
3409                        };
3410
3411                        if should_expand_hunk {
3412                            did_expand_hunks = true;
3413                            log::trace!(
3414                                "expanding hunk {:?}, excerpt:{:?}",
3415                                hunk_excerpt_start..hunk_excerpt_end,
3416                                excerpt.id
3417                            );
3418
3419                            if !hunk.diff_base_byte_range.is_empty()
3420                                && hunk_buffer_range.start >= edit_buffer_start
3421                                && hunk_buffer_range.start <= excerpt_buffer_end
3422                                && dbg!(snapshot.show_deleted_hunks)
3423                            {
3424                                let base_text = diff.base_text();
3425                                let mut text_cursor =
3426                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3427                                let mut base_text_summary = text_cursor
3428                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3429
3430                                let mut has_trailing_newline = false;
3431                                if base_text_summary.last_line_chars > 0 {
3432                                    base_text_summary += TextSummary::newline();
3433                                    has_trailing_newline = true;
3434                                }
3435
3436                                new_diff_transforms.push(
3437                                    DiffTransform::DeletedHunk {
3438                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3439                                        summary: base_text_summary,
3440                                        buffer_id: excerpt.buffer_id,
3441                                        hunk_info,
3442                                        has_trailing_newline,
3443                                    },
3444                                    (),
3445                                );
3446                            }
3447
3448                            if !hunk_buffer_range.is_empty() {
3449                                *end_of_current_insert =
3450                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3451                            }
3452                        }
3453                    }
3454                }
3455            }
3456
3457            if excerpts.end() <= edit.new.end {
3458                excerpts.next();
3459            } else {
3460                break;
3461            }
3462        }
3463
3464        did_expand_hunks || !old_expanded_hunks.is_empty()
3465    }
3466
3467    fn append_diff_transforms(
3468        new_transforms: &mut SumTree<DiffTransform>,
3469        subtree: SumTree<DiffTransform>,
3470    ) {
3471        if let Some(DiffTransform::BufferContent {
3472            inserted_hunk_info,
3473            summary,
3474        }) = subtree.first()
3475            && Self::extend_last_buffer_content_transform(
3476                new_transforms,
3477                *inserted_hunk_info,
3478                *summary,
3479            )
3480        {
3481            let mut cursor = subtree.cursor::<()>(());
3482            cursor.next();
3483            cursor.next();
3484            new_transforms.append(cursor.suffix(), ());
3485            return;
3486        }
3487        new_transforms.append(subtree, ());
3488    }
3489
3490    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3491        if let DiffTransform::BufferContent {
3492            inserted_hunk_info: inserted_hunk_anchor,
3493            summary,
3494        } = transform
3495            && Self::extend_last_buffer_content_transform(
3496                new_transforms,
3497                inserted_hunk_anchor,
3498                summary,
3499            )
3500        {
3501            return;
3502        }
3503        new_transforms.push(transform, ());
3504    }
3505
3506    fn push_buffer_content_transform(
3507        old_snapshot: &MultiBufferSnapshot,
3508        new_transforms: &mut SumTree<DiffTransform>,
3509        end_offset: ExcerptOffset,
3510        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3511    ) {
3512        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3513            (end_offset.min(insertion_end_offset), Some(hunk_info))
3514        });
3515        let unchanged_region = [(end_offset, None)];
3516
3517        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3518        {
3519            let start_offset = new_transforms.summary().excerpt_len();
3520            if end_offset <= start_offset {
3521                continue;
3522            }
3523            let summary_to_add = old_snapshot
3524                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3525
3526            if !Self::extend_last_buffer_content_transform(
3527                new_transforms,
3528                inserted_hunk_info,
3529                summary_to_add,
3530            ) {
3531                new_transforms.push(
3532                    DiffTransform::BufferContent {
3533                        summary: summary_to_add,
3534                        inserted_hunk_info,
3535                    },
3536                    (),
3537                )
3538            }
3539        }
3540    }
3541
3542    fn extend_last_buffer_content_transform(
3543        new_transforms: &mut SumTree<DiffTransform>,
3544        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3545        summary_to_add: MBTextSummary,
3546    ) -> bool {
3547        let mut did_extend = false;
3548        new_transforms.update_last(
3549            |last_transform| {
3550                if let DiffTransform::BufferContent {
3551                    summary,
3552                    inserted_hunk_info: inserted_hunk_anchor,
3553                } = last_transform
3554                    && *inserted_hunk_anchor == new_inserted_hunk_info
3555                {
3556                    *summary += summary_to_add;
3557                    did_extend = true;
3558                }
3559            },
3560            (),
3561        );
3562        did_extend
3563    }
3564}
3565
3566fn build_excerpt_ranges(
3567    ranges: impl IntoIterator<Item = Range<Point>>,
3568    context_line_count: u32,
3569    buffer_snapshot: &BufferSnapshot,
3570) -> Vec<ExcerptRange<Point>> {
3571    ranges
3572        .into_iter()
3573        .map(|range| {
3574            let start_row = range.start.row.saturating_sub(context_line_count);
3575            let start = Point::new(start_row, 0);
3576            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3577            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3578            ExcerptRange {
3579                context: start..end,
3580                primary: range,
3581            }
3582        })
3583        .collect()
3584}
3585
3586#[cfg(any(test, feature = "test-support"))]
3587impl MultiBuffer {
3588    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3589        let buffer = cx.new(|cx| Buffer::local(text, cx));
3590        cx.new(|cx| Self::singleton(buffer, cx))
3591    }
3592
3593    pub fn build_multi<const COUNT: usize>(
3594        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3595        cx: &mut gpui::App,
3596    ) -> Entity<Self> {
3597        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3598        for (text, ranges) in excerpts {
3599            let buffer = cx.new(|cx| Buffer::local(text, cx));
3600            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3601            multi.update(cx, |multi, cx| {
3602                multi.push_excerpts(buffer, excerpt_ranges, cx)
3603            });
3604        }
3605
3606        multi
3607    }
3608
3609    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3610        cx.new(|cx| Self::singleton(buffer, cx))
3611    }
3612
3613    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3614        cx.new(|cx| {
3615            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3616            let mutation_count = rng.random_range(1..=5);
3617            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3618            multibuffer
3619        })
3620    }
3621
3622    pub fn randomly_edit(
3623        &mut self,
3624        rng: &mut impl rand::Rng,
3625        edit_count: usize,
3626        cx: &mut Context<Self>,
3627    ) {
3628        use util::RandomCharIter;
3629
3630        let snapshot = self.read(cx);
3631        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3632        let mut last_end = None;
3633        for _ in 0..edit_count {
3634            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3635                break;
3636            }
3637
3638            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3639            let end =
3640                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3641            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3642            last_end = Some(end);
3643
3644            let mut range = start..end;
3645            if rng.random_bool(0.2) {
3646                mem::swap(&mut range.start, &mut range.end);
3647            }
3648
3649            let new_text_len = rng.random_range(0..10);
3650            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3651
3652            edits.push((range, new_text.into()));
3653        }
3654        log::info!("mutating multi-buffer with {:?}", edits);
3655        drop(snapshot);
3656
3657        self.edit(edits, None, cx);
3658    }
3659
3660    pub fn randomly_edit_excerpts(
3661        &mut self,
3662        rng: &mut impl rand::Rng,
3663        mutation_count: usize,
3664        cx: &mut Context<Self>,
3665    ) {
3666        use rand::prelude::*;
3667        use std::env;
3668        use util::RandomCharIter;
3669
3670        let max_excerpts = env::var("MAX_EXCERPTS")
3671            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3672            .unwrap_or(5);
3673
3674        let mut buffers = Vec::new();
3675        for _ in 0..mutation_count {
3676            if rng.random_bool(0.05) {
3677                log::info!("Clearing multi-buffer");
3678                self.clear(cx);
3679                continue;
3680            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3681                let ids = self.excerpt_ids();
3682                let mut excerpts = HashSet::default();
3683                for _ in 0..rng.random_range(0..ids.len()) {
3684                    excerpts.extend(ids.choose(rng).copied());
3685                }
3686
3687                let line_count = rng.random_range(0..5);
3688
3689                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3690
3691                self.expand_excerpts(
3692                    excerpts.iter().cloned(),
3693                    line_count,
3694                    ExpandExcerptDirection::UpAndDown,
3695                    cx,
3696                );
3697                continue;
3698            }
3699
3700            let excerpt_ids = self.excerpt_ids();
3701            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3702                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3703                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3704                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3705                    let buffer = buffers.last().unwrap().read(cx);
3706                    log::info!(
3707                        "Creating new buffer {} with text: {:?}",
3708                        buffer.remote_id(),
3709                        buffer.text()
3710                    );
3711                    buffers.last().unwrap().clone()
3712                } else {
3713                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3714                };
3715
3716                let buffer = buffer_handle.read(cx);
3717                let buffer_text = buffer.text();
3718                let ranges = (0..rng.random_range(0..5))
3719                    .map(|_| {
3720                        let end_ix =
3721                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3722                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3723                        ExcerptRange::new(start_ix..end_ix)
3724                    })
3725                    .collect::<Vec<_>>();
3726                log::info!(
3727                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3728                    buffer_handle.read(cx).remote_id(),
3729                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3730                    ranges
3731                        .iter()
3732                        .map(|r| &buffer_text[r.context.clone()])
3733                        .collect::<Vec<_>>()
3734                );
3735
3736                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3737                log::info!("Inserted with ids: {:?}", excerpt_id);
3738            } else {
3739                let remove_count = rng.random_range(1..=excerpt_ids.len());
3740                let mut excerpts_to_remove = excerpt_ids
3741                    .choose_multiple(rng, remove_count)
3742                    .cloned()
3743                    .collect::<Vec<_>>();
3744                let snapshot = self.snapshot.borrow();
3745                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3746                drop(snapshot);
3747                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3748                self.remove_excerpts(excerpts_to_remove, cx);
3749            }
3750        }
3751    }
3752
3753    pub fn randomly_mutate(
3754        &mut self,
3755        rng: &mut impl rand::Rng,
3756        mutation_count: usize,
3757        cx: &mut Context<Self>,
3758    ) {
3759        use rand::prelude::*;
3760
3761        if rng.random_bool(0.7) || self.singleton {
3762            let buffer = self
3763                .buffers
3764                .values()
3765                .choose(rng)
3766                .map(|state| state.buffer.clone());
3767
3768            if let Some(buffer) = buffer {
3769                buffer.update(cx, |buffer, cx| {
3770                    if rng.random() {
3771                        buffer.randomly_edit(rng, mutation_count, cx);
3772                    } else {
3773                        buffer.randomly_undo_redo(rng, cx);
3774                    }
3775                });
3776            } else {
3777                self.randomly_edit(rng, mutation_count, cx);
3778            }
3779        } else {
3780            self.randomly_edit_excerpts(rng, mutation_count, cx);
3781        }
3782
3783        self.check_invariants(cx);
3784    }
3785
3786    fn check_invariants(&self, cx: &App) {
3787        self.read(cx).check_invariants();
3788    }
3789}
3790
3791impl EventEmitter<Event> for MultiBuffer {}
3792
3793impl MultiBufferSnapshot {
3794    pub fn text(&self) -> String {
3795        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3796            .map(|chunk| chunk.text)
3797            .collect()
3798    }
3799
3800    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3801        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3802            .flat_map(|c| c.chars().rev())
3803    }
3804
3805    fn reversed_chunks_in_range(
3806        &self,
3807        range: Range<MultiBufferOffset>,
3808    ) -> ReversedMultiBufferChunks<'_> {
3809        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3810        cursor.seek(&range.end);
3811        let current_chunks = cursor.region().as_ref().map(|region| {
3812            let start_overshoot = range.start.saturating_sub(region.range.start);
3813            let end_overshoot = range.end - region.range.start;
3814            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3815            let start = region.buffer_range.start + start_overshoot;
3816            region.buffer.reversed_chunks_in_range(start..end)
3817        });
3818        ReversedMultiBufferChunks {
3819            cursor,
3820            current_chunks,
3821            start: range.start,
3822            offset: range.end,
3823        }
3824    }
3825
3826    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3827        let offset = position.to_offset(self);
3828        self.text_for_range(offset..self.len())
3829            .flat_map(|chunk| chunk.chars())
3830    }
3831
3832    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3833        self.chunks(range, false).map(|chunk| chunk.text)
3834    }
3835
3836    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3837        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3838            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3839    }
3840
3841    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3842    where
3843        T: ToOffset,
3844    {
3845        let position = position.to_offset(self);
3846        position == self.clip_offset(position, Bias::Left)
3847            && self
3848                .bytes_in_range(position..self.len())
3849                .flatten()
3850                .copied()
3851                .take(needle.len())
3852                .eq(needle.bytes())
3853    }
3854
3855    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3856        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3857    }
3858
3859    pub fn diff_hunks_in_range<T: ToPoint>(
3860        &self,
3861        range: Range<T>,
3862    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3863        let query_range = range.start.to_point(self)..range.end.to_point(self);
3864        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3865            let diff = self.diffs.get(&buffer.remote_id())?;
3866            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3867                if let Some(main_buffer) = &diff.main_buffer {
3868                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3869                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3870                    Box::new(
3871                        diff.hunks_intersecting_base_text_range(
3872                            buffer_start..buffer_end,
3873                            main_buffer,
3874                        )
3875                        .map(move |hunk| (hunk, buffer, true)),
3876                    )
3877                } else {
3878                    let buffer_start = buffer.anchor_before(buffer_range.start);
3879                    let buffer_end = buffer.anchor_after(buffer_range.end);
3880                    Box::new(
3881                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3882                            .map(move |hunk| (hunk, buffer, false)),
3883                    )
3884                };
3885            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3886                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3887                    return None;
3888                }
3889                let range = if is_inverted {
3890                    hunk.diff_base_byte_range.to_point(&buffer)
3891                } else {
3892                    hunk.range.clone()
3893                };
3894                Some((range, (hunk, is_inverted)))
3895            }))
3896        })
3897        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3898            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3899            {
3900                return None;
3901            }
3902            let end_row = if range.end.column == 0 {
3903                range.end.row
3904            } else {
3905                range.end.row + 1
3906            };
3907
3908            let word_diffs = (!hunk.base_word_diffs.is_empty()
3909                || !hunk.buffer_word_diffs.is_empty())
3910            .then(|| {
3911                let hunk_start_offset = if is_inverted {
3912                    Anchor::in_buffer(
3913                        excerpt.id,
3914                        excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3915                    )
3916                    .to_offset(self)
3917                } else {
3918                    Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_offset(self)
3919                };
3920
3921                let mut word_diffs = hunk
3922                    .base_word_diffs
3923                    .iter()
3924                    .map(|diff| hunk_start_offset + diff.start..hunk_start_offset + diff.end)
3925                    .collect::<Vec<_>>();
3926                if !is_inverted {
3927                    word_diffs.extend(
3928                        hunk.buffer_word_diffs
3929                            .into_iter()
3930                            .map(|diff| Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)),
3931                    );
3932                }
3933                word_diffs
3934            })
3935            .unwrap_or_default();
3936
3937            let buffer_range = if is_inverted {
3938                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3939                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3940            } else {
3941                hunk.buffer_range.clone()
3942            };
3943            Some(MultiBufferDiffHunk {
3944                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3945                buffer_id: excerpt.buffer_id,
3946                excerpt_id: excerpt.id,
3947                buffer_range,
3948                word_diffs,
3949                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3950                    ..BufferOffset(hunk.diff_base_byte_range.end),
3951                secondary_status: hunk.secondary_status,
3952            })
3953        })
3954    }
3955
3956    fn excerpts_for_range<T: ToOffset>(
3957        &self,
3958        range: Range<T>,
3959    ) -> impl Iterator<Item = &Excerpt> + '_ {
3960        let range = range.start.to_offset(self)..range.end.to_offset(self);
3961        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3962        cursor.seek(&range.start);
3963        std::iter::from_fn(move || {
3964            let region = cursor.region()?;
3965            if region.range.start > range.end
3966                || region.range.start == range.end && region.range.start > range.start
3967            {
3968                return None;
3969            }
3970            cursor.next_excerpt();
3971            Some(region.excerpt)
3972        })
3973    }
3974
3975    pub fn excerpt_ids_for_range<T: ToOffset>(
3976        &self,
3977        range: Range<T>,
3978    ) -> impl Iterator<Item = ExcerptId> + '_ {
3979        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3980    }
3981
3982    pub fn buffer_ids_for_range<T: ToOffset>(
3983        &self,
3984        range: Range<T>,
3985    ) -> impl Iterator<Item = BufferId> + '_ {
3986        self.excerpts_for_range(range)
3987            .map(|excerpt| excerpt.buffer_id)
3988    }
3989
3990    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3991        &self,
3992        ranges: impl Iterator<Item = Range<T>>,
3993    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3994        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3995    }
3996
3997    pub fn range_to_buffer_ranges<T: ToOffset>(
3998        &self,
3999        range: Range<T>,
4000    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4001        let start = range.start.to_offset(self);
4002        let end = range.end.to_offset(self);
4003
4004        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4005        cursor.seek(&start);
4006
4007        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
4008        while let Some(region) = cursor.region() {
4009            if region.range.start > end {
4010                break;
4011            }
4012            if region.is_main_buffer {
4013                let start_overshoot = start.saturating_sub(region.range.start);
4014                let end_overshoot = end.saturating_sub(region.range.start);
4015                let start = region
4016                    .buffer_range
4017                    .end
4018                    .min(region.buffer_range.start + start_overshoot);
4019                let end = region
4020                    .buffer_range
4021                    .end
4022                    .min(region.buffer_range.start + end_overshoot);
4023                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
4024                    *excerpt_id == region.excerpt.id && prev_range.end == start
4025                }) {
4026                    prev.1.end = end;
4027                } else {
4028                    result.push((region.buffer, start..end, region.excerpt.id));
4029                }
4030            }
4031            cursor.next();
4032        }
4033        result
4034    }
4035
4036    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4037        &self,
4038        range: Range<T>,
4039    ) -> impl Iterator<
4040        Item = (
4041            &BufferSnapshot,
4042            Range<BufferOffset>,
4043            ExcerptId,
4044            Option<Anchor>,
4045        ),
4046    > + '_ {
4047        let start = range.start.to_offset(self);
4048        let end = range.end.to_offset(self);
4049
4050        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4051        cursor.seek(&start);
4052
4053        std::iter::from_fn(move || {
4054            let region = cursor.region()?;
4055            if region.range.start > end {
4056                return None;
4057            }
4058            let start_overshoot = start.saturating_sub(region.range.start);
4059            let end_overshoot = end.saturating_sub(region.range.start);
4060            let start = region
4061                .buffer_range
4062                .end
4063                .min(region.buffer_range.start + start_overshoot);
4064            let end = region
4065                .buffer_range
4066                .end
4067                .min(region.buffer_range.start + end_overshoot);
4068
4069            let region_excerpt_id = region.excerpt.id;
4070            let deleted_hunk_anchor = if region.is_main_buffer {
4071                None
4072            } else {
4073                Some(self.anchor_before(region.range.start))
4074            };
4075            let result = (
4076                region.buffer,
4077                start..end,
4078                region_excerpt_id,
4079                deleted_hunk_anchor,
4080            );
4081            cursor.next();
4082            Some(result)
4083        })
4084    }
4085
4086    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4087    /// coordinates.
4088    ///
4089    /// The given callback will be called for every excerpt intersecting the given range. It will
4090    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4091    /// The callback should return an iterator of metadata items from that buffer, each paired
4092    /// with a buffer range.
4093    ///
4094    /// The returned iterator yields each of these metadata items, paired with its range in
4095    /// multi-buffer coordinates.
4096    fn lift_buffer_metadata<'a, MBD, M, I>(
4097        &'a self,
4098        query_range: Range<MBD>,
4099        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4100    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4101    where
4102        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4103        MBD: MultiBufferDimension
4104            + Ord
4105            + Sub<Output = MBD::TextDimension>
4106            + ops::Add<MBD::TextDimension, Output = MBD>
4107            + ops::AddAssign<MBD::TextDimension>,
4108        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4109            + ops::Add<Output = MBD::TextDimension>
4110            + AddAssign<MBD::TextDimension>
4111            + Ord,
4112    {
4113        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4114        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4115
4116        // Find the excerpt and buffer offset where the given range ends.
4117        cursor.seek(&query_range.end);
4118        let mut range_end = None;
4119        while let Some(region) = cursor.region() {
4120            if region.is_main_buffer {
4121                let mut buffer_end = region.buffer_range.start;
4122                let overshoot = if query_range.end > region.range.start {
4123                    query_range.end - region.range.start
4124                } else {
4125                    <MBD::TextDimension>::default()
4126                };
4127                buffer_end = buffer_end + overshoot;
4128                range_end = Some((region.excerpt.id, buffer_end));
4129                break;
4130            }
4131            cursor.next();
4132        }
4133
4134        cursor.seek(&query_range.start);
4135
4136        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4137            && region.range.start > MBD::default()
4138        {
4139            cursor.prev()
4140        }
4141
4142        iter::from_fn(move || {
4143            loop {
4144                let excerpt = cursor.excerpt()?;
4145
4146                // If we have already retrieved metadata for this excerpt, continue to use it.
4147                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4148                    .as_mut()
4149                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4150                {
4151                    Some(metadata)
4152                }
4153                // Otherwise, compute the intersection of the input range with the excerpt's range,
4154                // and retrieve the metadata for the resulting range.
4155                else {
4156                    let region = cursor.region()?;
4157                    let mut buffer_start;
4158                    if region.is_main_buffer {
4159                        buffer_start = region.buffer_range.start;
4160                        if query_range.start > region.range.start {
4161                            let overshoot = query_range.start - region.range.start;
4162                            buffer_start = buffer_start + overshoot;
4163                        }
4164                        buffer_start = buffer_start.min(region.buffer_range.end);
4165                    } else {
4166                        buffer_start = cursor.main_buffer_position()?;
4167                    };
4168                    let mut buffer_end = excerpt
4169                        .range
4170                        .context
4171                        .end
4172                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4173                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4174                        && excerpt.id == end_excerpt_id
4175                    {
4176                        buffer_end = buffer_end.min(end_buffer_offset);
4177                    }
4178
4179                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4180                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4181                    })
4182                };
4183
4184                // Visit each metadata item.
4185                if let Some((metadata_buffer_range, metadata)) =
4186                    metadata_iter.and_then(Iterator::next)
4187                {
4188                    // Find the multibuffer regions that contain the start and end of
4189                    // the metadata item's range.
4190                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4191                        while let Some(region) = cursor.region() {
4192                            if region.is_main_buffer
4193                                && (region.buffer_range.end >= metadata_buffer_range.start
4194                                    || cursor.is_at_end_of_excerpt())
4195                            {
4196                                break;
4197                            }
4198                            cursor.next();
4199                        }
4200                    }
4201                    let start_region = cursor.region()?;
4202                    while let Some(region) = cursor.region() {
4203                        if region.is_main_buffer
4204                            && (region.buffer_range.end > metadata_buffer_range.end
4205                                || cursor.is_at_end_of_excerpt())
4206                        {
4207                            break;
4208                        }
4209                        cursor.next();
4210                    }
4211                    let end_region = cursor.region();
4212
4213                    // Convert the metadata item's range into multibuffer coordinates.
4214                    let mut start_position = start_region.range.start;
4215                    let region_buffer_start = start_region.buffer_range.start;
4216                    if start_region.is_main_buffer
4217                        && metadata_buffer_range.start > region_buffer_start
4218                    {
4219                        start_position =
4220                            start_position + (metadata_buffer_range.start - region_buffer_start);
4221                        start_position = start_position.min(start_region.range.end);
4222                    }
4223
4224                    let mut end_position = self.max_position();
4225                    if let Some(end_region) = &end_region {
4226                        end_position = end_region.range.start;
4227                        debug_assert!(end_region.is_main_buffer);
4228                        let region_buffer_start = end_region.buffer_range.start;
4229                        if metadata_buffer_range.end > region_buffer_start {
4230                            end_position =
4231                                end_position + (metadata_buffer_range.end - region_buffer_start);
4232                        }
4233                        end_position = end_position.min(end_region.range.end);
4234                    }
4235
4236                    if start_position <= query_range.end && end_position >= query_range.start {
4237                        return Some((start_position..end_position, metadata, excerpt));
4238                    }
4239                }
4240                // When there are no more metadata items for this excerpt, move to the next excerpt.
4241                else {
4242                    current_excerpt_metadata.take();
4243                    if let Some((end_excerpt_id, _)) = range_end
4244                        && excerpt.id == end_excerpt_id
4245                    {
4246                        return None;
4247                    }
4248                    cursor.next_excerpt();
4249                }
4250            }
4251        })
4252    }
4253
4254    // FIXME need to make this work with inverted diffs
4255    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4256        let offset = position.to_offset(self);
4257
4258        let mut cursor = self
4259            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4260            );
4261        cursor.seek(&DimensionPair {
4262            key: offset,
4263            value: None,
4264        });
4265        cursor.seek_to_start_of_current_excerpt();
4266        let excerpt = cursor.excerpt()?;
4267
4268        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4269        let current_position = self
4270            .anchor_before(offset)
4271            .text_anchor
4272            .to_offset(&excerpt.buffer);
4273        let excerpt_end = excerpt
4274            .buffer
4275            .anchor_before(excerpt_end.min(current_position));
4276
4277        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4278            for hunk in diff.hunks_intersecting_range_rev(
4279                excerpt.range.context.start..excerpt_end,
4280                &excerpt.buffer,
4281            ) {
4282                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4283                if hunk_end >= current_position {
4284                    continue;
4285                }
4286                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4287                return Some(MultiBufferRow(start.row));
4288            }
4289        }
4290
4291        loop {
4292            cursor.prev_excerpt();
4293            let excerpt = cursor.excerpt()?;
4294
4295            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4296                continue;
4297            };
4298            let mut hunks =
4299                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4300            let Some(hunk) = hunks.next() else {
4301                continue;
4302            };
4303            let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4304            return Some(MultiBufferRow(start.row));
4305        }
4306    }
4307
4308    pub fn has_diff_hunks(&self) -> bool {
4309        self.diffs.values().any(|diff| !diff.is_empty())
4310    }
4311
4312    pub fn is_inside_word<T: ToOffset>(
4313        &self,
4314        position: T,
4315        scope_context: Option<CharScopeContext>,
4316    ) -> bool {
4317        let position = position.to_offset(self);
4318        let classifier = self
4319            .char_classifier_at(position)
4320            .scope_context(scope_context);
4321        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4322        let prev_char_kind = self
4323            .reversed_chars_at(position)
4324            .next()
4325            .map(|c| classifier.kind(c));
4326        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4327    }
4328
4329    pub fn surrounding_word<T: ToOffset>(
4330        &self,
4331        start: T,
4332        scope_context: Option<CharScopeContext>,
4333    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4334        let mut start = start.to_offset(self);
4335        let mut end = start;
4336        let mut next_chars = self.chars_at(start).peekable();
4337        let mut prev_chars = self.reversed_chars_at(start).peekable();
4338
4339        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4340
4341        let word_kind = cmp::max(
4342            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4343            next_chars.peek().copied().map(|c| classifier.kind(c)),
4344        );
4345
4346        for ch in prev_chars {
4347            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4348                start -= ch.len_utf8();
4349            } else {
4350                break;
4351            }
4352        }
4353
4354        for ch in next_chars {
4355            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4356                end += ch.len_utf8();
4357            } else {
4358                break;
4359            }
4360        }
4361
4362        (start..end, word_kind)
4363    }
4364
4365    pub fn char_kind_before<T: ToOffset>(
4366        &self,
4367        start: T,
4368        scope_context: Option<CharScopeContext>,
4369    ) -> Option<CharKind> {
4370        let start = start.to_offset(self);
4371        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4372        self.reversed_chars_at(start)
4373            .next()
4374            .map(|ch| classifier.kind(ch))
4375    }
4376
4377    pub fn is_singleton(&self) -> bool {
4378        self.singleton
4379    }
4380
4381    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4382        if self.singleton {
4383            self.excerpts
4384                .iter()
4385                .next()
4386                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4387        } else {
4388            None
4389        }
4390    }
4391
4392    pub fn len(&self) -> MultiBufferOffset {
4393        self.diff_transforms.summary().output.len
4394    }
4395
4396    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4397        MBD::from_summary(&self.text_summary())
4398    }
4399
4400    pub fn is_empty(&self) -> bool {
4401        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4402    }
4403
4404    pub fn widest_line_number(&self) -> u32 {
4405        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4406        self.excerpts.summary().widest_line_number + 1
4407    }
4408
4409    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4410        let range = range.start.to_offset(self)..range.end.to_offset(self);
4411        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4412        excerpts.seek(&range.start);
4413
4414        let mut chunk;
4415        let mut has_trailing_newline;
4416        let excerpt_bytes;
4417        if let Some(region) = excerpts.region() {
4418            let mut bytes = region.buffer.bytes_in_range(
4419                region.buffer_range.start + (range.start - region.range.start)
4420                    ..(region.buffer_range.start + (range.end - region.range.start))
4421                        .min(region.buffer_range.end),
4422            );
4423            chunk = bytes.next().unwrap_or(&[][..]);
4424            excerpt_bytes = Some(bytes);
4425            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4426            if chunk.is_empty() && has_trailing_newline {
4427                chunk = b"\n";
4428                has_trailing_newline = false;
4429            }
4430        } else {
4431            chunk = &[][..];
4432            excerpt_bytes = None;
4433            has_trailing_newline = false;
4434        };
4435
4436        MultiBufferBytes {
4437            range,
4438            cursor: excerpts,
4439            excerpt_bytes,
4440            has_trailing_newline,
4441            chunk,
4442        }
4443    }
4444
4445    pub fn reversed_bytes_in_range<T: ToOffset>(
4446        &self,
4447        range: Range<T>,
4448    ) -> ReversedMultiBufferBytes<'_> {
4449        let range = range.start.to_offset(self)..range.end.to_offset(self);
4450        let mut chunks = self.reversed_chunks_in_range(range.clone());
4451        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4452        ReversedMultiBufferBytes {
4453            range,
4454            chunks,
4455            chunk,
4456        }
4457    }
4458
4459    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4460        let mut cursor = self.cursor::<Point, Point>();
4461        cursor.seek(&Point::new(start_row.0, 0));
4462        let mut result = MultiBufferRows {
4463            point: Point::new(0, 0),
4464            is_empty: self.excerpts.is_empty(),
4465            is_singleton: self.is_singleton(),
4466            cursor,
4467        };
4468        result.seek(start_row);
4469        result
4470    }
4471
4472    pub fn chunks<T: ToOffset>(
4473        &self,
4474        range: Range<T>,
4475        language_aware: bool,
4476    ) -> MultiBufferChunks<'_> {
4477        let mut chunks = MultiBufferChunks {
4478            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4479                ..ExcerptDimension(MultiBufferOffset::ZERO),
4480            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4481            excerpts: self.excerpts.cursor(()),
4482            diff_transforms: self.diff_transforms.cursor(()),
4483            diffs: &self.diffs,
4484            diff_base_chunks: None,
4485            excerpt_chunks: None,
4486            buffer_chunk: None,
4487            language_aware,
4488        };
4489        let range = range.start.to_offset(self)..range.end.to_offset(self);
4490        chunks.seek(range);
4491        chunks
4492    }
4493
4494    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4495        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4496    }
4497
4498    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4499        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4500    }
4501
4502    pub fn clip_offset_utf16(
4503        &self,
4504        offset: MultiBufferOffsetUtf16,
4505        bias: Bias,
4506    ) -> MultiBufferOffsetUtf16 {
4507        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4508    }
4509
4510    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4511        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4512            buffer.clip_point_utf16(Unclipped(point), bias)
4513        })
4514    }
4515
4516    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4517        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4518    }
4519
4520    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4521        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4522    }
4523
4524    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4525        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4526    }
4527
4528    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4529        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4530    }
4531
4532    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4533        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4534    }
4535
4536    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4537        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4538    }
4539
4540    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4541        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4542    }
4543
4544    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4545        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4546    }
4547
4548    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4549        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4550    }
4551
4552    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4553        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4554    }
4555
4556    fn clip_dimension<MBD, BD>(
4557        &self,
4558        position: MBD,
4559        bias: Bias,
4560        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4561    ) -> MBD
4562    where
4563        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4564        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4565    {
4566        let mut cursor = self.cursor::<MBD, BD>();
4567        cursor.seek(&position);
4568        if let Some(region) = cursor.region() {
4569            if position >= region.range.end {
4570                return region.range.end;
4571            }
4572            let overshoot = position - region.range.start;
4573            let mut buffer_position = region.buffer_range.start;
4574            buffer_position += overshoot;
4575            let clipped_buffer_position =
4576                clip_buffer_position(region.buffer, buffer_position, bias);
4577            let mut position = region.range.start;
4578            position += clipped_buffer_position - region.buffer_range.start;
4579            position
4580        } else {
4581            self.max_position()
4582        }
4583    }
4584
4585    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4586        &self,
4587        key: MBR1,
4588        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4589    ) -> MBR2
4590    where
4591        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4592        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4593        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4594        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4595    {
4596        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4597        cursor.seek(&DimensionPair { key, value: None });
4598        if let Some(region) = cursor.region() {
4599            if key >= region.range.end.key {
4600                return region.range.end.value.unwrap();
4601            }
4602            let start_key = region.range.start.key;
4603            let start_value = region.range.start.value.unwrap();
4604            let buffer_start_key = region.buffer_range.start.key;
4605            let buffer_start_value = region.buffer_range.start.value.unwrap();
4606            let mut buffer_key = buffer_start_key;
4607            buffer_key += key - start_key;
4608            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4609            let mut result = start_value;
4610            result += buffer_value - buffer_start_value;
4611            result
4612        } else {
4613            self.max_position()
4614        }
4615    }
4616
4617    pub fn point_to_buffer_offset<T: ToOffset>(
4618        &self,
4619        point: T,
4620    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4621        let offset = point.to_offset(self);
4622        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4623        cursor.seek(&offset);
4624        let region = cursor.region()?;
4625        let overshoot = offset - region.range.start;
4626        let buffer_offset = region.buffer_range.start + overshoot;
4627        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4628            && region.has_trailing_newline
4629            && !region.is_main_buffer
4630        {
4631            let main_buffer_position = cursor.main_buffer_position()?;
4632            let buffer_snapshot = &cursor.excerpt()?.buffer;
4633            return Some((buffer_snapshot, main_buffer_position));
4634        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4635            return None;
4636        }
4637        Some((region.buffer, buffer_offset))
4638    }
4639
4640    pub fn point_to_buffer_point(
4641        &self,
4642        point: Point,
4643    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4644        let mut cursor = self.cursor::<Point, Point>();
4645        cursor.seek(&point);
4646        let region = cursor.region()?;
4647        let overshoot = point - region.range.start;
4648        let buffer_point = region.buffer_range.start + overshoot;
4649        let excerpt = cursor.excerpt()?;
4650        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4651            && region.has_trailing_newline
4652            && !region.is_main_buffer
4653        {
4654            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4655        } else if buffer_point > region.buffer.max_point() {
4656            return None;
4657        }
4658        Some((region.buffer, buffer_point, excerpt.id))
4659    }
4660
4661    pub fn suggested_indents(
4662        &self,
4663        rows: impl IntoIterator<Item = u32>,
4664        cx: &App,
4665    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4666        let mut result = BTreeMap::new();
4667
4668        let mut rows_for_excerpt = Vec::new();
4669        let mut cursor = self.cursor::<Point, Point>();
4670        let mut rows = rows.into_iter().peekable();
4671        let mut prev_row = u32::MAX;
4672        let mut prev_language_indent_size = IndentSize::default();
4673
4674        while let Some(row) = rows.next() {
4675            cursor.seek(&Point::new(row, 0));
4676            let Some(region) = cursor.region() else {
4677                continue;
4678            };
4679
4680            // Retrieve the language and indent size once for each disjoint region being indented.
4681            let single_indent_size = if row.saturating_sub(1) == prev_row {
4682                prev_language_indent_size
4683            } else {
4684                region
4685                    .buffer
4686                    .language_indent_size_at(Point::new(row, 0), cx)
4687            };
4688            prev_language_indent_size = single_indent_size;
4689            prev_row = row;
4690
4691            let start_buffer_row = region.buffer_range.start.row;
4692            let start_multibuffer_row = region.range.start.row;
4693            let end_multibuffer_row = region.range.end.row;
4694
4695            rows_for_excerpt.push(row);
4696            while let Some(next_row) = rows.peek().copied() {
4697                if end_multibuffer_row > next_row {
4698                    rows_for_excerpt.push(next_row);
4699                    rows.next();
4700                } else {
4701                    break;
4702                }
4703            }
4704
4705            let buffer_rows = rows_for_excerpt
4706                .drain(..)
4707                .map(|row| start_buffer_row + row - start_multibuffer_row);
4708            let buffer_indents = region
4709                .buffer
4710                .suggested_indents(buffer_rows, single_indent_size);
4711            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4712                (
4713                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4714                    indent,
4715                )
4716            });
4717            result.extend(multibuffer_indents);
4718        }
4719
4720        result
4721    }
4722
4723    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4724        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4725            let mut size = buffer.indent_size_for_line(range.start.row);
4726            size.len = size
4727                .len
4728                .min(range.end.column)
4729                .saturating_sub(range.start.column);
4730            size
4731        } else {
4732            IndentSize::spaces(0)
4733        }
4734    }
4735
4736    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4737        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4738            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4739        } else {
4740            LineIndent::spaces(0)
4741        }
4742    }
4743
4744    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4745        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4746
4747        if self.language_settings(cx).extend_comment_on_newline
4748            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4749        {
4750            let delimiters = language_scope.line_comment_prefixes();
4751            for delimiter in delimiters {
4752                if *self
4753                    .chars_at(Point::new(row.0, indent.len() as u32))
4754                    .take(delimiter.chars().count())
4755                    .collect::<String>()
4756                    .as_str()
4757                    == **delimiter
4758                {
4759                    indent.push_str(delimiter);
4760                    break;
4761                }
4762            }
4763        }
4764
4765        indent
4766    }
4767
4768    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4769    where
4770        T: ToOffset,
4771    {
4772        for char in self.reversed_chars_at(position) {
4773            if !char.is_whitespace() {
4774                return false;
4775            }
4776            if char == '\n' {
4777                return true;
4778            }
4779        }
4780        true
4781    }
4782
4783    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4784        while row.0 > 0 {
4785            row.0 -= 1;
4786            if !self.is_line_blank(row) {
4787                return Some(row);
4788            }
4789        }
4790        None
4791    }
4792
4793    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4794        if let Some((_, range)) = self.buffer_line_for_row(row) {
4795            range.end.column - range.start.column
4796        } else {
4797            0
4798        }
4799    }
4800
4801    pub fn buffer_line_for_row(
4802        &self,
4803        row: MultiBufferRow,
4804    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4805        let mut cursor = self.cursor::<Point, Point>();
4806        let point = Point::new(row.0, 0);
4807        cursor.seek(&point);
4808        let region = cursor.region()?;
4809        let overshoot = point.min(region.range.end) - region.range.start;
4810        let buffer_point = region.buffer_range.start + overshoot;
4811        if buffer_point.row > region.buffer_range.end.row {
4812            return None;
4813        }
4814        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4815        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4816            .min(region.buffer_range.end);
4817        Some((region.buffer, line_start..line_end))
4818    }
4819
4820    pub fn max_point(&self) -> Point {
4821        self.text_summary().lines
4822    }
4823
4824    pub fn max_row(&self) -> MultiBufferRow {
4825        MultiBufferRow(self.text_summary().lines.row)
4826    }
4827
4828    pub fn text_summary(&self) -> MBTextSummary {
4829        self.diff_transforms.summary().output
4830    }
4831
4832    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4833    where
4834        MBD: MultiBufferDimension + AddAssign,
4835        O: ToOffset,
4836    {
4837        let range = range.start.to_offset(self)..range.end.to_offset(self);
4838        let mut cursor = self
4839            .diff_transforms
4840            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4841        cursor.seek(&range.start, Bias::Right);
4842
4843        let Some(first_transform) = cursor.item() else {
4844            return MBD::from_summary(&MBTextSummary::default());
4845        };
4846
4847        let diff_transform_start = cursor.start().0;
4848        let diff_transform_end = cursor.end().0;
4849        let diff_start = range.start;
4850        let start_overshoot = diff_start - diff_transform_start;
4851        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4852
4853        let mut result = match first_transform {
4854            DiffTransform::BufferContent { .. } => {
4855                let excerpt_start = cursor.start().1 + start_overshoot;
4856                let excerpt_end = cursor.start().1 + end_overshoot;
4857                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4858            }
4859            DiffTransform::DeletedHunk {
4860                buffer_id,
4861                base_text_byte_range,
4862                has_trailing_newline,
4863                ..
4864            } => {
4865                let buffer_start = base_text_byte_range.start + start_overshoot;
4866                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4867                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4868                    panic!("{:?} is in non-existent deleted hunk", range.start)
4869                };
4870
4871                let include_trailing_newline =
4872                    *has_trailing_newline && range.end >= diff_transform_end;
4873                if include_trailing_newline {
4874                    buffer_end -= 1;
4875                }
4876
4877                let mut summary = base_text
4878                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4879
4880                if include_trailing_newline {
4881                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4882                        &TextSummary::newline(),
4883                    ))
4884                }
4885
4886                let mut result = MBD::default();
4887                result.add_text_dim(&summary);
4888                result
4889            }
4890        };
4891        if range.end < diff_transform_end {
4892            return result;
4893        }
4894
4895        cursor.next();
4896        result.add_mb_text_summary(
4897            &cursor
4898                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4899                .0,
4900        );
4901
4902        let Some(last_transform) = cursor.item() else {
4903            return result;
4904        };
4905
4906        let overshoot = range.end - cursor.start().0;
4907        let suffix = match last_transform {
4908            DiffTransform::BufferContent { .. } => {
4909                let end = cursor.start().1 + overshoot;
4910                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4911            }
4912            DiffTransform::DeletedHunk {
4913                base_text_byte_range,
4914                buffer_id,
4915                has_trailing_newline,
4916                ..
4917            } => {
4918                let buffer_end = base_text_byte_range.start + overshoot;
4919                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4920                    panic!("{:?} is in non-existent deleted hunk", range.end)
4921                };
4922
4923                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4924                    base_text_byte_range.start..buffer_end,
4925                );
4926                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4927                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4928                        &TextSummary::from("\n"),
4929                    ))
4930                }
4931
4932                let mut result = MBD::default();
4933                result.add_text_dim(&suffix);
4934                result
4935            }
4936        };
4937
4938        result += suffix;
4939        result
4940    }
4941
4942    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4943    where
4944        MBD: MultiBufferDimension + AddAssign,
4945    {
4946        let mut summary = MBD::default();
4947        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4948        cursor.seek(&range.start, Bias::Right);
4949        if let Some(excerpt) = cursor.item() {
4950            let mut end_before_newline = cursor.end();
4951            if excerpt.has_trailing_newline {
4952                end_before_newline -= 1;
4953            }
4954
4955            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4956            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4957            let end_in_excerpt =
4958                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4959            summary.add_text_dim(
4960                &excerpt
4961                    .buffer
4962                    .text_summary_for_range::<MBD::TextDimension, _>(
4963                        start_in_excerpt..end_in_excerpt,
4964                    ),
4965            );
4966
4967            if range.end > end_before_newline {
4968                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4969            }
4970
4971            cursor.next();
4972        }
4973
4974        if range.end > *cursor.start() {
4975            summary += cursor
4976                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4977                .0;
4978            if let Some(excerpt) = cursor.item() {
4979                range.end = cmp::max(*cursor.start(), range.end);
4980
4981                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4982                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4983                summary.add_text_dim(
4984                    &excerpt
4985                        .buffer
4986                        .text_summary_for_range::<MBD::TextDimension, _>(
4987                            excerpt_start..end_in_excerpt,
4988                        ),
4989                );
4990            }
4991        }
4992
4993        summary
4994    }
4995
4996    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4997    where
4998        MBD: MultiBufferDimension
4999            + Ord
5000            + Sub<Output = MBD::TextDimension>
5001            + AddAssign<MBD::TextDimension>,
5002        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5003    {
5004        self.summaries_for_anchors([anchor])[0]
5005    }
5006
5007    fn resolve_summary_for_anchor<MBD>(
5008        &self,
5009        anchor: &Anchor,
5010        excerpt_position: ExcerptDimension<MBD>,
5011        diff_transforms: &mut Cursor<
5012            DiffTransform,
5013            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5014        >,
5015    ) -> MBD
5016    where
5017        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5018    {
5019        loop {
5020            let transform_end_position = diff_transforms.end().0;
5021            let at_transform_end =
5022                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5023            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5024                diff_transforms.next();
5025                continue;
5026            }
5027
5028            let mut position = diff_transforms.start().1;
5029            match diff_transforms.item() {
5030                Some(DiffTransform::DeletedHunk {
5031                    buffer_id,
5032                    base_text_byte_range,
5033                    ..
5034                }) => {
5035                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5036                        && let Some(base_text) =
5037                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5038                        && diff_base_anchor.is_valid(&base_text)
5039                    {
5040                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5041                        if base_text_offset >= base_text_byte_range.start
5042                            && base_text_offset <= base_text_byte_range.end
5043                        {
5044                            let position_in_hunk = base_text
5045                                .text_summary_for_range::<MBD::TextDimension, _>(
5046                                    base_text_byte_range.start..base_text_offset,
5047                                );
5048                            position.0.add_text_dim(&position_in_hunk);
5049                        } else if at_transform_end {
5050                            diff_transforms.next();
5051                            continue;
5052                        }
5053                    }
5054                }
5055                _ => {
5056                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5057                        diff_transforms.next();
5058                        continue;
5059                    }
5060                    let overshoot = excerpt_position - diff_transforms.start().0;
5061                    position += overshoot;
5062                }
5063            }
5064
5065            return position.0;
5066        }
5067    }
5068
5069    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5070        let mut cursor = self
5071            .excerpts
5072            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5073        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5074
5075        cursor.seek(&Some(locator), Bias::Left);
5076        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5077            cursor.prev();
5078        }
5079
5080        let mut position = cursor.start().1;
5081        if let Some(excerpt) = cursor.item()
5082            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5083        {
5084            let excerpt_buffer_start = excerpt
5085                .buffer
5086                .offset_for_anchor(&excerpt.range.context.start);
5087            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5088            let buffer_position = cmp::min(
5089                excerpt_buffer_end,
5090                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5091            );
5092            if buffer_position > excerpt_buffer_start {
5093                position += buffer_position - excerpt_buffer_start;
5094            }
5095        }
5096        position
5097    }
5098
5099    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5100        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5101            excerpt_id = *replacement;
5102        }
5103        excerpt_id
5104    }
5105
5106    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5107    where
5108        MBD: MultiBufferDimension
5109            + Ord
5110            + Sub<Output = MBD::TextDimension>
5111            + AddAssign<MBD::TextDimension>,
5112        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5113        I: 'a + IntoIterator<Item = &'a Anchor>,
5114    {
5115        let mut anchors = anchors.into_iter().peekable();
5116        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5117        let mut diff_transforms_cursor = self
5118            .diff_transforms
5119            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5120        diff_transforms_cursor.next();
5121
5122        let mut summaries = Vec::new();
5123        while let Some(anchor) = anchors.peek() {
5124            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5125
5126            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5127                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5128            });
5129
5130            let locator = self.excerpt_locator_for_id(excerpt_id);
5131            cursor.seek_forward(locator, Bias::Left);
5132            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5133                cursor.prev();
5134            }
5135
5136            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5137            if let Some(excerpt) = cursor.item() {
5138                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5139                    let position = self.resolve_summary_for_anchor(
5140                        &Anchor::min(),
5141                        excerpt_start_position,
5142                        &mut diff_transforms_cursor,
5143                    );
5144                    summaries.extend(excerpt_anchors.map(|_| position));
5145                    continue;
5146                }
5147                let excerpt_buffer_start = excerpt
5148                    .range
5149                    .context
5150                    .start
5151                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5152                let excerpt_buffer_end = excerpt
5153                    .range
5154                    .context
5155                    .end
5156                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5157                for (buffer_summary, anchor) in excerpt
5158                    .buffer
5159                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5160                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5161                    )
5162                {
5163                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5164                    let mut position = excerpt_start_position;
5165                    if summary > excerpt_buffer_start {
5166                        position += summary - excerpt_buffer_start;
5167                    }
5168
5169                    if diff_transforms_cursor.start().0 < position {
5170                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5171                    }
5172
5173                    summaries.push(self.resolve_summary_for_anchor(
5174                        anchor,
5175                        position,
5176                        &mut diff_transforms_cursor,
5177                    ));
5178                }
5179            } else {
5180                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5181                let position = self.resolve_summary_for_anchor(
5182                    &Anchor::max(),
5183                    excerpt_start_position,
5184                    &mut diff_transforms_cursor,
5185                );
5186                summaries.extend(excerpt_anchors.map(|_| position));
5187            }
5188        }
5189
5190        summaries
5191    }
5192
5193    pub fn dimensions_from_points<'a, MBD>(
5194        &'a self,
5195        points: impl 'a + IntoIterator<Item = Point>,
5196    ) -> impl 'a + Iterator<Item = MBD>
5197    where
5198        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5199    {
5200        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5201        cursor.seek(&DimensionPair {
5202            key: Point::default(),
5203            value: None,
5204        });
5205        let mut points = points.into_iter();
5206        iter::from_fn(move || {
5207            let point = points.next()?;
5208
5209            cursor.seek_forward(&DimensionPair {
5210                key: point,
5211                value: None,
5212            });
5213
5214            if let Some(region) = cursor.region() {
5215                let overshoot = point - region.range.start.key;
5216                let buffer_point = region.buffer_range.start + overshoot;
5217                let mut position = region.range.start.value.unwrap();
5218                position.add_text_dim(
5219                    &region
5220                        .buffer
5221                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5222                );
5223                if point == region.range.end.key && region.has_trailing_newline {
5224                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5225                }
5226                Some(position)
5227            } else {
5228                Some(MBD::from_summary(&self.text_summary()))
5229            }
5230        })
5231    }
5232
5233    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5234    where
5235        I: 'a + IntoIterator<Item = &'a Anchor>,
5236    {
5237        let mut anchors = anchors.into_iter().enumerate().peekable();
5238        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5239        cursor.next();
5240
5241        let mut result = Vec::new();
5242
5243        while let Some((_, anchor)) = anchors.peek() {
5244            let old_excerpt_id = anchor.excerpt_id;
5245
5246            // Find the location where this anchor's excerpt should be.
5247            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5248            cursor.seek_forward(&Some(old_locator), Bias::Left);
5249
5250            let next_excerpt = cursor.item();
5251            let prev_excerpt = cursor.prev_item();
5252
5253            // Process all of the anchors for this excerpt.
5254            while let Some((anchor_ix, &anchor)) =
5255                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5256            {
5257                let mut anchor = anchor;
5258
5259                // Leave min and max anchors unchanged if invalid or
5260                // if the old excerpt still exists at this location
5261                let mut kept_position = next_excerpt
5262                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5263                    || old_excerpt_id == ExcerptId::max()
5264                    || old_excerpt_id == ExcerptId::min();
5265
5266                // If the old excerpt no longer exists at this location, then attempt to
5267                // find an equivalent position for this anchor in an adjacent excerpt.
5268                if !kept_position {
5269                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5270                        if excerpt.contains(&anchor) {
5271                            anchor.excerpt_id = excerpt.id;
5272                            kept_position = true;
5273                            break;
5274                        }
5275                    }
5276                }
5277
5278                // If there's no adjacent excerpt that contains the anchor's position,
5279                // then report that the anchor has lost its position.
5280                if !kept_position {
5281                    anchor = if let Some(excerpt) = next_excerpt {
5282                        let mut text_anchor = excerpt
5283                            .range
5284                            .context
5285                            .start
5286                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5287                        if text_anchor
5288                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5289                            .is_gt()
5290                        {
5291                            text_anchor = excerpt.range.context.end;
5292                        }
5293                        Anchor::in_buffer(excerpt.id, text_anchor)
5294                    } else if let Some(excerpt) = prev_excerpt {
5295                        let mut text_anchor = excerpt
5296                            .range
5297                            .context
5298                            .end
5299                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5300                        if text_anchor
5301                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5302                            .is_lt()
5303                        {
5304                            text_anchor = excerpt.range.context.start;
5305                        }
5306                        Anchor::in_buffer(excerpt.id, text_anchor)
5307                    } else if anchor.text_anchor.bias == Bias::Left {
5308                        Anchor::min()
5309                    } else {
5310                        Anchor::max()
5311                    };
5312                }
5313
5314                result.push((anchor_ix, anchor, kept_position));
5315            }
5316        }
5317        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5318        result
5319    }
5320
5321    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5322        self.anchor_at(position, Bias::Left)
5323    }
5324
5325    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5326        self.anchor_at(position, Bias::Right)
5327    }
5328
5329    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5330        let offset = position.to_offset(self);
5331
5332        // Find the given position in the diff transforms. Determine the corresponding
5333        // offset in the excerpts, and whether the position is within a deleted hunk.
5334        let mut diff_transforms = self
5335            .diff_transforms
5336            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5337        diff_transforms.seek(&offset, Bias::Right);
5338
5339        if offset == diff_transforms.start().0
5340            && bias == Bias::Left
5341            && let Some(prev_item) = diff_transforms.prev_item()
5342            && let DiffTransform::DeletedHunk { .. } = prev_item
5343        {
5344            diff_transforms.prev();
5345        }
5346        let offset_in_transform = offset - diff_transforms.start().0;
5347        let mut excerpt_offset = diff_transforms.start().1;
5348        let mut diff_base_anchor = None;
5349        if let Some(DiffTransform::DeletedHunk {
5350            buffer_id,
5351            base_text_byte_range,
5352            has_trailing_newline,
5353            ..
5354        }) = diff_transforms.item()
5355        {
5356            let diff = self.diffs.get(buffer_id).expect("missing diff");
5357            if offset_in_transform > base_text_byte_range.len() {
5358                debug_assert!(*has_trailing_newline);
5359                bias = Bias::Right;
5360            } else {
5361                diff_base_anchor = Some(
5362                    diff.base_text()
5363                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5364                );
5365                bias = Bias::Left;
5366            }
5367        } else {
5368            excerpt_offset += MultiBufferOffset(offset_in_transform);
5369        };
5370
5371        let mut excerpts = self
5372            .excerpts
5373            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5374        excerpts.seek(&excerpt_offset, Bias::Right);
5375        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5376            excerpts.prev();
5377        }
5378        if let Some(excerpt) = excerpts.item() {
5379            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5380            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5381                overshoot -= 1;
5382                bias = Bias::Right;
5383            }
5384
5385            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5386            let text_anchor =
5387                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5388            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5389            match diff_base_anchor {
5390                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5391                None => anchor,
5392            }
5393        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5394        {
5395            Anchor::min()
5396        } else {
5397            Anchor::max()
5398        }
5399    }
5400
5401    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5402    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5403        let (excerpt, buffer, _) = self.as_singleton()?;
5404        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5405            Some(Anchor::in_buffer(*excerpt, text_anchor))
5406        } else {
5407            None
5408        }
5409    }
5410
5411    /// Returns an anchor for the given excerpt and text anchor,
5412    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5413    pub fn anchor_range_in_excerpt(
5414        &self,
5415        excerpt_id: ExcerptId,
5416        text_anchor: Range<text::Anchor>,
5417    ) -> Option<Range<Anchor>> {
5418        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5419
5420        Some(
5421            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5422                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5423        )
5424    }
5425
5426    /// Returns an anchor for the given excerpt and text anchor,
5427    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5428    pub fn anchor_in_excerpt(
5429        &self,
5430        excerpt_id: ExcerptId,
5431        text_anchor: text::Anchor,
5432    ) -> Option<Anchor> {
5433        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5434        Self::anchor_in_excerpt_(excerpt, text_anchor)
5435    }
5436
5437    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5438    pub fn anchors_in_excerpt(
5439        &self,
5440        excerpt_id: ExcerptId,
5441        text_anchors: impl IntoIterator<Item = text::Anchor>,
5442    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5443        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5444        Some(
5445            text_anchors
5446                .into_iter()
5447                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5448        )
5449    }
5450
5451    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5452        match text_anchor.buffer_id {
5453            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5454            Some(_) => return None,
5455            None if text_anchor.is_max() || text_anchor.is_min() => {
5456                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5457            }
5458            None => return None,
5459        }
5460
5461        let context = &excerpt.range.context;
5462        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5463            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5464        {
5465            return None;
5466        }
5467
5468        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5469    }
5470
5471    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5472        Some(self.excerpt(excerpt_id)?.range.context.clone())
5473    }
5474
5475    pub fn excerpt_range_for_excerpt(
5476        &self,
5477        excerpt_id: ExcerptId,
5478    ) -> Option<ExcerptRange<text::Anchor>> {
5479        Some(self.excerpt(excerpt_id)?.range.clone())
5480    }
5481
5482    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5483        if anchor.is_min() || anchor.is_max() {
5484            // todo(lw): should be `!self.is_empty()`
5485            true
5486        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5487            excerpt.buffer.can_resolve(&anchor.text_anchor)
5488        } else {
5489            false
5490        }
5491    }
5492
5493    pub fn excerpts(
5494        &self,
5495    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5496        self.excerpts
5497            .iter()
5498            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5499    }
5500
5501    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5502    where
5503        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5504        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5505    {
5506        let excerpts = self.excerpts.cursor(());
5507        let diff_transforms = self.diff_transforms.cursor(());
5508        MultiBufferCursor {
5509            excerpts,
5510            diff_transforms,
5511            diffs: &self.diffs,
5512            cached_region: None,
5513        }
5514    }
5515
5516    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5517        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5518        let mut excerpts = self
5519            .excerpts
5520            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5521        excerpts.seek(&Some(start_locator), Bias::Left);
5522        excerpts.prev();
5523
5524        let mut diff_transforms = self
5525            .diff_transforms
5526            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5527        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5528        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5529            diff_transforms.next();
5530        }
5531
5532        let excerpt = excerpts.item()?;
5533        Some(MultiBufferExcerpt {
5534            excerpt,
5535            offset: diff_transforms.start().output_dimension.0,
5536            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5537            excerpt_offset: excerpts.start().1,
5538            diff_transforms,
5539        })
5540    }
5541
5542    pub fn excerpt_boundaries_in_range<R, T>(
5543        &self,
5544        range: R,
5545    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5546    where
5547        R: RangeBounds<T>,
5548        T: ToOffset,
5549    {
5550        let start_offset;
5551        let start = match range.start_bound() {
5552            Bound::Included(start) => {
5553                start_offset = start.to_offset(self);
5554                Bound::Included(start_offset)
5555            }
5556            Bound::Excluded(_) => {
5557                panic!("not supported")
5558            }
5559            Bound::Unbounded => {
5560                start_offset = MultiBufferOffset::ZERO;
5561                Bound::Unbounded
5562            }
5563        };
5564        let end = match range.end_bound() {
5565            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5566            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5567            Bound::Unbounded => Bound::Unbounded,
5568        };
5569        let bounds = (start, end);
5570        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5571        cursor.seek(&DimensionPair {
5572            key: start_offset,
5573            value: None,
5574        });
5575
5576        if cursor
5577            .region()
5578            .is_some_and(|region| bounds.contains(&region.range.start.key))
5579        {
5580            cursor.prev_excerpt();
5581        } else {
5582            cursor.seek_to_start_of_current_excerpt();
5583        }
5584        let mut prev_region = cursor.region();
5585
5586        cursor.next_excerpt();
5587
5588        iter::from_fn(move || {
5589            loop {
5590                if self.singleton {
5591                    return None;
5592                }
5593
5594                let next_region = cursor.region()?;
5595                cursor.next_excerpt();
5596                if !bounds.contains(&next_region.range.start.key) {
5597                    prev_region = Some(next_region);
5598                    continue;
5599                }
5600
5601                let next_region_start = next_region.range.start.value.unwrap();
5602                let next_region_end = if let Some(region) = cursor.region() {
5603                    region.range.start.value.unwrap()
5604                } else {
5605                    self.max_point()
5606                };
5607
5608                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5609                    id: region.excerpt.id,
5610                    buffer: region.excerpt.buffer.clone(),
5611                    buffer_id: region.excerpt.buffer_id,
5612                    range: region.excerpt.range.clone(),
5613                    end_row: MultiBufferRow(next_region_start.row),
5614                });
5615
5616                let next = ExcerptInfo {
5617                    id: next_region.excerpt.id,
5618                    buffer: next_region.excerpt.buffer.clone(),
5619                    buffer_id: next_region.excerpt.buffer_id,
5620                    range: next_region.excerpt.range.clone(),
5621                    end_row: if next_region.excerpt.has_trailing_newline {
5622                        MultiBufferRow(next_region_end.row - 1)
5623                    } else {
5624                        MultiBufferRow(next_region_end.row)
5625                    },
5626                };
5627
5628                let row = MultiBufferRow(next_region_start.row);
5629
5630                prev_region = Some(next_region);
5631
5632                return Some(ExcerptBoundary { row, prev, next });
5633            }
5634        })
5635    }
5636
5637    pub fn edit_count(&self) -> usize {
5638        self.edit_count
5639    }
5640
5641    pub fn non_text_state_update_count(&self) -> usize {
5642        self.non_text_state_update_count
5643    }
5644
5645    /// Returns the smallest enclosing bracket ranges containing the given range or
5646    /// None if no brackets contain range or the range is not contained in a single
5647    /// excerpt
5648    ///
5649    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5650    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5651        &self,
5652        range: Range<T>,
5653        range_filter: Option<
5654            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5655        >,
5656    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5657        let range = range.start.to_offset(self)..range.end.to_offset(self);
5658        let mut excerpt = self.excerpt_containing(range.clone())?;
5659        let buffer = excerpt.buffer();
5660        let excerpt_buffer_range = excerpt.buffer_range();
5661
5662        // Filter to ranges contained in the excerpt
5663        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5664            excerpt_buffer_range.contains(&BufferOffset(open.start))
5665                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5666                && range_filter.is_none_or(|filter| {
5667                    filter(
5668                        buffer,
5669                        BufferOffset(open.start)..BufferOffset(close.end),
5670                        BufferOffset(close.start)..BufferOffset(close.end),
5671                    )
5672                })
5673        };
5674
5675        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5676            excerpt.map_range_to_buffer(range),
5677            Some(&range_filter),
5678        )?;
5679
5680        Some((
5681            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5682            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5683        ))
5684    }
5685
5686    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5687    /// not contained in a single excerpt
5688    pub fn enclosing_bracket_ranges<T: ToOffset>(
5689        &self,
5690        range: Range<T>,
5691    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5692    {
5693        let range = range.start.to_offset(self)..range.end.to_offset(self);
5694        let mut excerpt = self.excerpt_containing(range.clone())?;
5695
5696        Some(
5697            excerpt
5698                .buffer()
5699                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5700                .filter_map(move |pair| {
5701                    let open_range =
5702                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5703                    let close_range =
5704                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5705                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5706                        Some((
5707                            excerpt.map_range_from_buffer(open_range),
5708                            excerpt.map_range_from_buffer(close_range),
5709                        ))
5710                    } else {
5711                        None
5712                    }
5713                }),
5714        )
5715    }
5716
5717    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5718    /// not contained in a single excerpt
5719    pub fn text_object_ranges<T: ToOffset>(
5720        &self,
5721        range: Range<T>,
5722        options: TreeSitterOptions,
5723    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5724        let range = range.start.to_offset(self)..range.end.to_offset(self);
5725        self.excerpt_containing(range.clone())
5726            .map(|mut excerpt| {
5727                excerpt
5728                    .buffer()
5729                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5730                    .filter_map(move |(range, text_object)| {
5731                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5732                        if excerpt.contains_buffer_range(range.clone()) {
5733                            Some((excerpt.map_range_from_buffer(range), text_object))
5734                        } else {
5735                            None
5736                        }
5737                    })
5738            })
5739            .into_iter()
5740            .flatten()
5741    }
5742
5743    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5744    /// not contained in a single excerpt
5745    pub fn bracket_ranges<T: ToOffset>(
5746        &self,
5747        range: Range<T>,
5748    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5749    {
5750        let range = range.start.to_offset(self)..range.end.to_offset(self);
5751        let mut excerpt = self.excerpt_containing(range.clone())?;
5752        Some(
5753            excerpt
5754                .buffer()
5755                .bracket_ranges(excerpt.map_range_to_buffer(range))
5756                .filter_map(move |pair| {
5757                    let open_range =
5758                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5759                    let close_range =
5760                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5761                    excerpt
5762                        .contains_buffer_range(open_range.start..close_range.end)
5763                        .then(|| BracketMatch {
5764                            open_range: excerpt.map_range_from_buffer(open_range),
5765                            close_range: excerpt.map_range_from_buffer(close_range),
5766                            color_index: pair.color_index,
5767                            newline_only: pair.newline_only,
5768                            syntax_layer_depth: pair.syntax_layer_depth,
5769                        })
5770                })
5771                .map(BracketMatch::bracket_ranges),
5772        )
5773    }
5774
5775    pub fn redacted_ranges<'a, T: ToOffset>(
5776        &'a self,
5777        range: Range<T>,
5778        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5779    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5780        let range = range.start.to_offset(self)..range.end.to_offset(self);
5781        self.lift_buffer_metadata(range, move |buffer, range| {
5782            if redaction_enabled(buffer.file()) {
5783                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5784            } else {
5785                None
5786            }
5787        })
5788        .map(|(range, _, _)| range)
5789    }
5790
5791    pub fn runnable_ranges(
5792        &self,
5793        range: Range<Anchor>,
5794    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5795        let range = range.start.to_offset(self)..range.end.to_offset(self);
5796        self.lift_buffer_metadata(range, move |buffer, range| {
5797            Some(
5798                buffer
5799                    .runnable_ranges(range.clone())
5800                    .filter(move |runnable| {
5801                        runnable.run_range.start >= range.start
5802                            && runnable.run_range.end < range.end
5803                    })
5804                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5805            )
5806        })
5807        .map(|(run_range, runnable, _)| (run_range, runnable))
5808    }
5809
5810    pub fn line_indents(
5811        &self,
5812        start_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(start_row.0, 0));
5818        iter::from_fn(move || {
5819            let mut region = cursor.region()?;
5820            while !buffer_filter(&region.excerpt.buffer) {
5821                cursor.next();
5822                region = cursor.region()?;
5823            }
5824            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5825            let buffer_start_row =
5826                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5827
5828            let buffer_end_row = if region.is_main_buffer
5829                && (region.has_trailing_newline || region.range.end == max_point)
5830            {
5831                region.buffer_range.end.row
5832            } else {
5833                region.buffer_range.end.row.saturating_sub(1)
5834            };
5835
5836            let line_indents = region
5837                .buffer
5838                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5839            cursor.next();
5840            Some(line_indents.map(move |(buffer_row, indent)| {
5841                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5842                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5843            }))
5844        })
5845        .flatten()
5846    }
5847
5848    pub fn reversed_line_indents(
5849        &self,
5850        end_row: MultiBufferRow,
5851        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5852    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5853        let max_point = self.max_point();
5854        let mut cursor = self.cursor::<Point, Point>();
5855        cursor.seek(&Point::new(end_row.0, 0));
5856        iter::from_fn(move || {
5857            let mut region = cursor.region()?;
5858            while !buffer_filter(&region.excerpt.buffer) {
5859                cursor.prev();
5860                region = cursor.region()?;
5861            }
5862
5863            let buffer_start_row = region.buffer_range.start.row;
5864            let buffer_end_row = if region.is_main_buffer
5865                && (region.has_trailing_newline || region.range.end == max_point)
5866            {
5867                region.buffer_range.end.row + 1
5868            } else {
5869                region.buffer_range.end.row
5870            };
5871
5872            let overshoot = end_row.0 - region.range.start.row;
5873            let buffer_end_row =
5874                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5875
5876            let line_indents = region
5877                .buffer
5878                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5879            cursor.prev();
5880            Some(line_indents.map(move |(buffer_row, indent)| {
5881                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5882                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5883            }))
5884        })
5885        .flatten()
5886    }
5887
5888    pub async fn enclosing_indent(
5889        &self,
5890        mut target_row: MultiBufferRow,
5891    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5892        let max_row = MultiBufferRow(self.max_point().row);
5893        if target_row >= max_row {
5894            return None;
5895        }
5896
5897        let mut target_indent = self.line_indent_for_row(target_row);
5898
5899        // If the current row is at the start of an indented block, we want to return this
5900        // block as the enclosing indent.
5901        if !target_indent.is_line_empty() && target_row < max_row {
5902            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5903            if !next_line_indent.is_line_empty()
5904                && target_indent.raw_len() < next_line_indent.raw_len()
5905            {
5906                target_indent = next_line_indent;
5907                target_row.0 += 1;
5908            }
5909        }
5910
5911        const SEARCH_ROW_LIMIT: u32 = 25000;
5912        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5913        const YIELD_INTERVAL: u32 = 100;
5914
5915        let mut accessed_row_counter = 0;
5916
5917        // If there is a blank line at the current row, search for the next non indented lines
5918        if target_indent.is_line_empty() {
5919            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5920            let end =
5921                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5922
5923            let mut non_empty_line_above = None;
5924            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5925                if row < start {
5926                    break;
5927                }
5928                accessed_row_counter += 1;
5929                if accessed_row_counter == YIELD_INTERVAL {
5930                    accessed_row_counter = 0;
5931                    yield_now().await;
5932                }
5933                if !indent.is_line_empty() {
5934                    non_empty_line_above = Some((row, indent));
5935                    break;
5936                }
5937            }
5938
5939            let mut non_empty_line_below = None;
5940            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5941                if row > end {
5942                    break;
5943                }
5944                accessed_row_counter += 1;
5945                if accessed_row_counter == YIELD_INTERVAL {
5946                    accessed_row_counter = 0;
5947                    yield_now().await;
5948                }
5949                if !indent.is_line_empty() {
5950                    non_empty_line_below = Some((row, indent));
5951                    break;
5952                }
5953            }
5954
5955            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5956                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5957                    if above_indent.raw_len() >= below_indent.raw_len() {
5958                        (above_row, above_indent)
5959                    } else {
5960                        (below_row, below_indent)
5961                    }
5962                }
5963                (Some(above), None) => above,
5964                (None, Some(below)) => below,
5965                _ => return None,
5966            };
5967
5968            target_indent = indent;
5969            target_row = row;
5970        }
5971
5972        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5973        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5974
5975        let mut start_indent = None;
5976        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5977            if row < start {
5978                break;
5979            }
5980            accessed_row_counter += 1;
5981            if accessed_row_counter == YIELD_INTERVAL {
5982                accessed_row_counter = 0;
5983                yield_now().await;
5984            }
5985            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5986                start_indent = Some((row, indent));
5987                break;
5988            }
5989        }
5990        let (start_row, start_indent_size) = start_indent?;
5991
5992        let mut end_indent = (end, None);
5993        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5994            if row > end {
5995                break;
5996            }
5997            accessed_row_counter += 1;
5998            if accessed_row_counter == YIELD_INTERVAL {
5999                accessed_row_counter = 0;
6000                yield_now().await;
6001            }
6002            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6003                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6004                break;
6005            }
6006        }
6007        let (end_row, end_indent_size) = end_indent;
6008
6009        let indent = if let Some(end_indent_size) = end_indent_size {
6010            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6011                start_indent_size
6012            } else {
6013                end_indent_size
6014            }
6015        } else {
6016            start_indent_size
6017        };
6018
6019        Some((start_row..end_row, indent))
6020    }
6021
6022    pub fn indent_guides_in_range<T: ToPoint>(
6023        &self,
6024        range: Range<T>,
6025        ignore_disabled_for_language: bool,
6026        cx: &App,
6027    ) -> impl Iterator<Item = IndentGuide> {
6028        let range = range.start.to_point(self)..range.end.to_point(self);
6029        let start_row = MultiBufferRow(range.start.row);
6030        let end_row = MultiBufferRow(range.end.row);
6031
6032        let mut row_indents = self.line_indents(start_row, |buffer| {
6033            let settings =
6034                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6035            settings.indent_guides.enabled || ignore_disabled_for_language
6036        });
6037
6038        let mut result = Vec::new();
6039        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6040
6041        let mut prev_settings = None;
6042        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6043            if first_row > end_row {
6044                break;
6045            }
6046            let current_depth = indent_stack.len() as u32;
6047
6048            // Avoid retrieving the language settings repeatedly for every buffer row.
6049            if let Some((prev_buffer_id, _)) = &prev_settings
6050                && prev_buffer_id != &buffer.remote_id()
6051            {
6052                prev_settings.take();
6053            }
6054            let settings = &prev_settings
6055                .get_or_insert_with(|| {
6056                    (
6057                        buffer.remote_id(),
6058                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6059                    )
6060                })
6061                .1;
6062            let tab_size = settings.tab_size.get();
6063
6064            // When encountering empty, continue until found useful line indent
6065            // then add to the indent stack with the depth found
6066            let mut found_indent = false;
6067            let mut last_row = first_row;
6068            if line_indent.is_line_blank() {
6069                while !found_indent {
6070                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6071                        break;
6072                    };
6073                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6074                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6075                        break;
6076                    }
6077
6078                    if new_line_indent.is_line_blank() {
6079                        continue;
6080                    }
6081                    last_row = target_row.min(end_row);
6082                    line_indent = new_line_indent;
6083                    found_indent = true;
6084                    break;
6085                }
6086            } else {
6087                found_indent = true
6088            }
6089
6090            let depth = if found_indent {
6091                line_indent.len(tab_size) / tab_size
6092            } else {
6093                0
6094            };
6095
6096            match depth.cmp(&current_depth) {
6097                cmp::Ordering::Less => {
6098                    for _ in 0..(current_depth - depth) {
6099                        let mut indent = indent_stack.pop().unwrap();
6100                        if last_row != first_row {
6101                            // In this case, we landed on an empty row, had to seek forward,
6102                            // and discovered that the indent we where on is ending.
6103                            // This means that the last display row must
6104                            // be on line that ends this indent range, so we
6105                            // should display the range up to the first non-empty line
6106                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6107                        }
6108
6109                        result.push(indent)
6110                    }
6111                }
6112                cmp::Ordering::Greater => {
6113                    for next_depth in current_depth..depth {
6114                        indent_stack.push(IndentGuide {
6115                            buffer_id: buffer.remote_id(),
6116                            start_row: first_row,
6117                            end_row: last_row,
6118                            depth: next_depth,
6119                            tab_size,
6120                            settings: settings.indent_guides.clone(),
6121                        });
6122                    }
6123                }
6124                _ => {}
6125            }
6126
6127            for indent in indent_stack.iter_mut() {
6128                indent.end_row = last_row;
6129            }
6130        }
6131
6132        result.extend(indent_stack);
6133        result.into_iter()
6134    }
6135
6136    pub fn trailing_excerpt_update_count(&self) -> usize {
6137        self.trailing_excerpt_update_count
6138    }
6139
6140    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6141        self.point_to_buffer_offset(point)
6142            .and_then(|(buffer, _)| buffer.file())
6143    }
6144
6145    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6146        self.point_to_buffer_offset(offset)
6147            .and_then(|(buffer, offset)| buffer.language_at(offset))
6148    }
6149
6150    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6151        self.excerpts
6152            .first()
6153            .map(|excerpt| &excerpt.buffer)
6154            .map(|buffer| {
6155                language_settings(
6156                    buffer.language().map(|language| language.name()),
6157                    buffer.file(),
6158                    cx,
6159                )
6160            })
6161            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6162    }
6163
6164    pub fn language_settings_at<'a, T: ToOffset>(
6165        &'a self,
6166        point: T,
6167        cx: &'a App,
6168    ) -> Cow<'a, LanguageSettings> {
6169        let mut language = None;
6170        let mut file = None;
6171        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6172            language = buffer.language_at(offset);
6173            file = buffer.file();
6174        }
6175        language_settings(language.map(|l| l.name()), file, cx)
6176    }
6177
6178    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6179        self.point_to_buffer_offset(point)
6180            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6181    }
6182
6183    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6184        self.point_to_buffer_offset(point)
6185            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6186            .unwrap_or_default()
6187    }
6188
6189    pub fn language_indent_size_at<T: ToOffset>(
6190        &self,
6191        position: T,
6192        cx: &App,
6193    ) -> Option<IndentSize> {
6194        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6195        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6196    }
6197
6198    pub fn is_dirty(&self) -> bool {
6199        self.is_dirty
6200    }
6201
6202    pub fn has_deleted_file(&self) -> bool {
6203        self.has_deleted_file
6204    }
6205
6206    pub fn has_conflict(&self) -> bool {
6207        self.has_conflict
6208    }
6209
6210    pub fn has_diagnostics(&self) -> bool {
6211        self.excerpts
6212            .iter()
6213            .any(|excerpt| excerpt.buffer.has_diagnostics())
6214    }
6215
6216    pub fn diagnostic_group(
6217        &self,
6218        buffer_id: BufferId,
6219        group_id: usize,
6220    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6221        self.lift_buffer_metadata::<Point, _, _>(
6222            Point::zero()..self.max_point(),
6223            move |buffer, range| {
6224                if buffer.remote_id() != buffer_id {
6225                    return None;
6226                };
6227                Some(
6228                    buffer
6229                        .diagnostics_in_range(range, false)
6230                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6231                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6232                )
6233            },
6234        )
6235        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6236    }
6237
6238    pub fn diagnostics_in_range<'a, MBD>(
6239        &'a self,
6240        range: Range<MBD>,
6241    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6242    where
6243        MBD::TextDimension: 'a
6244            + text::ToOffset
6245            + text::FromAnchor
6246            + Sub<Output = MBD::TextDimension>
6247            + fmt::Debug
6248            + ops::Add<Output = MBD::TextDimension>
6249            + ops::AddAssign
6250            + Ord,
6251        MBD: MultiBufferDimension
6252            + Ord
6253            + Sub<Output = MBD::TextDimension>
6254            + ops::Add<MBD::TextDimension, Output = MBD>
6255            + ops::AddAssign<MBD::TextDimension>
6256            + 'a,
6257    {
6258        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6259            Some(
6260                buffer
6261                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6262                    .map(|entry| (entry.range, entry.diagnostic)),
6263            )
6264        })
6265        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6266    }
6267
6268    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6269        &'a self,
6270        range: Range<MBD>,
6271    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6272    where
6273        MBD: MultiBufferDimension
6274            + Ord
6275            + Sub<Output = MBD::TextDimension>
6276            + ops::Add<MBD::TextDimension, Output = MBD>
6277            + ops::AddAssign<MBD::TextDimension>,
6278        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6279            + ops::Add<Output = MBD::TextDimension>
6280            + text::ToOffset
6281            + text::FromAnchor
6282            + AddAssign<MBD::TextDimension>
6283            + Ord,
6284    {
6285        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6286            Some(
6287                buffer
6288                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6289                    .map(|entry| (entry.range, entry.diagnostic)),
6290            )
6291        })
6292        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6293    }
6294
6295    pub fn syntax_ancestor<T: ToOffset>(
6296        &self,
6297        range: Range<T>,
6298    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6299        let range = range.start.to_offset(self)..range.end.to_offset(self);
6300        let mut excerpt = self.excerpt_containing(range.clone())?;
6301        let node = excerpt
6302            .buffer()
6303            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6304        let node_range = node.byte_range();
6305        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6306        if !excerpt.contains_buffer_range(node_range.clone()) {
6307            return None;
6308        };
6309        Some((node, excerpt.map_range_from_buffer(node_range)))
6310    }
6311
6312    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6313        let (excerpt_id, _, buffer) = self.as_singleton()?;
6314        let outline = buffer.outline(theme);
6315        Some(Outline::new(
6316            outline
6317                .items
6318                .into_iter()
6319                .flat_map(|item| {
6320                    Some(OutlineItem {
6321                        depth: item.depth,
6322                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6323                        source_range_for_text: self
6324                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6325                        text: item.text,
6326                        highlight_ranges: item.highlight_ranges,
6327                        name_ranges: item.name_ranges,
6328                        body_range: item.body_range.and_then(|body_range| {
6329                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6330                        }),
6331                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6332                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6333                        }),
6334                    })
6335                })
6336                .collect(),
6337        ))
6338    }
6339
6340    pub fn symbols_containing<T: ToOffset>(
6341        &self,
6342        offset: T,
6343        theme: Option<&SyntaxTheme>,
6344    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6345        let anchor = self.anchor_before(offset);
6346        let excerpt @ &Excerpt {
6347            id: excerpt_id,
6348            buffer_id,
6349            ref buffer,
6350            ..
6351        } = self.excerpt(anchor.excerpt_id)?;
6352        if cfg!(debug_assertions) {
6353            match anchor.text_anchor.buffer_id {
6354                // we clearly are hitting this according to sentry, but in what situations can this occur?
6355                Some(anchor_buffer_id) => {
6356                    assert_eq!(
6357                        anchor_buffer_id, buffer_id,
6358                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6359                    )
6360                }
6361                None => assert!(anchor.is_max()),
6362            }
6363        };
6364        Some((
6365            buffer_id,
6366            buffer
6367                .symbols_containing(anchor.text_anchor, theme)
6368                .into_iter()
6369                .flat_map(|item| {
6370                    Some(OutlineItem {
6371                        depth: item.depth,
6372                        source_range_for_text: Anchor::range_in_buffer(
6373                            excerpt_id,
6374                            item.source_range_for_text,
6375                        ),
6376                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6377                        text: item.text,
6378                        highlight_ranges: item.highlight_ranges,
6379                        name_ranges: item.name_ranges,
6380                        body_range: item
6381                            .body_range
6382                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6383                        annotation_range: item
6384                            .annotation_range
6385                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6386                    })
6387                })
6388                .collect(),
6389        ))
6390    }
6391
6392    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6393        if id == ExcerptId::min() {
6394            Locator::min_ref()
6395        } else if id == ExcerptId::max() {
6396            Locator::max_ref()
6397        } else {
6398            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6399            if let Some(entry) = item
6400                && entry.id == id
6401            {
6402                return &entry.locator;
6403            }
6404            panic!("invalid excerpt id {id:?}")
6405        }
6406    }
6407
6408    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6409    fn excerpt_locators_for_ids(
6410        &self,
6411        ids: impl IntoIterator<Item = ExcerptId>,
6412    ) -> SmallVec<[Locator; 1]> {
6413        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6414        sorted_ids.sort_unstable();
6415        sorted_ids.dedup();
6416        let mut locators = SmallVec::new();
6417
6418        while sorted_ids.last() == Some(&ExcerptId::max()) {
6419            sorted_ids.pop();
6420            locators.push(Locator::max());
6421        }
6422
6423        let mut sorted_ids = sorted_ids.into_iter().peekable();
6424        locators.extend(
6425            sorted_ids
6426                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6427                .map(|_| Locator::min()),
6428        );
6429
6430        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6431        for id in sorted_ids {
6432            if cursor.seek_forward(&id, Bias::Left) {
6433                locators.push(cursor.item().unwrap().locator.clone());
6434            } else {
6435                panic!("invalid excerpt id {:?}", id);
6436            }
6437        }
6438
6439        locators.sort_unstable();
6440        locators
6441    }
6442
6443    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6444        Some(self.excerpt(excerpt_id)?.buffer_id)
6445    }
6446
6447    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6448        Some(&self.excerpt(excerpt_id)?.buffer)
6449    }
6450
6451    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6452        let mut cursor = self
6453            .excerpts
6454            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6455        let locator = self.excerpt_locator_for_id(excerpt_id);
6456        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6457        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6458            sought_exact = true;
6459            cursor.prev();
6460        } else if excerpt_id == ExcerptId::min() {
6461            sought_exact = true;
6462        }
6463        if sought_exact {
6464            let start = cursor.start().1;
6465            let end = cursor.end().1;
6466            let mut diff_transforms = self
6467                .diff_transforms
6468                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6469            diff_transforms.seek(&start, Bias::Left);
6470            let overshoot = start - diff_transforms.start().0;
6471            let start = diff_transforms.start().1 + overshoot;
6472            diff_transforms.seek(&end, Bias::Right);
6473            let overshoot = end - diff_transforms.start().0;
6474            let end = diff_transforms.start().1 + overshoot;
6475            Some(start.0..end.0)
6476        } else {
6477            None
6478        }
6479    }
6480
6481    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6482    /// to have the same excerpt id as the one passed in, with the exception of
6483    /// `ExcerptId::max()`.
6484    ///
6485    /// Callers of this function should generally use the resulting excerpt's `id` field
6486    /// afterwards.
6487    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6488        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6489        let locator = self.excerpt_locator_for_id(excerpt_id);
6490        cursor.seek(&Some(locator), Bias::Left);
6491        if let Some(excerpt) = cursor.item()
6492            && excerpt.id == excerpt_id
6493        {
6494            return Some(excerpt);
6495        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6496            cursor.prev();
6497            return cursor.item();
6498        }
6499        None
6500    }
6501
6502    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6503    pub fn excerpt_containing<T: ToOffset>(
6504        &self,
6505        range: Range<T>,
6506    ) -> Option<MultiBufferExcerpt<'_>> {
6507        let range = range.start.to_offset(self)..range.end.to_offset(self);
6508        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6509        cursor.seek(&range.start);
6510
6511        let start_excerpt = cursor.excerpt()?;
6512        if range.end != range.start {
6513            cursor.seek_forward(&range.end);
6514            if cursor.excerpt()?.id != start_excerpt.id {
6515                return None;
6516            }
6517        }
6518
6519        cursor.seek_to_start_of_current_excerpt();
6520        let region = cursor.region()?;
6521        let offset = region.range.start;
6522        let buffer_offset = start_excerpt.buffer_start_offset();
6523        let excerpt_offset = *cursor.excerpts.start();
6524        Some(MultiBufferExcerpt {
6525            diff_transforms: cursor.diff_transforms,
6526            excerpt: start_excerpt,
6527            offset,
6528            buffer_offset,
6529            excerpt_offset,
6530        })
6531    }
6532
6533    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6534        if let Some(id) = anchor.text_anchor.buffer_id {
6535            return Some(id);
6536        }
6537        let excerpt = self.excerpt_containing(anchor..anchor)?;
6538        Some(excerpt.buffer_id())
6539    }
6540
6541    pub fn selections_in_range<'a>(
6542        &'a self,
6543        range: &'a Range<Anchor>,
6544        include_local: bool,
6545    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6546        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6547        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6548        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6549        cursor.seek(start_locator, Bias::Left);
6550        cursor
6551            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6552            .flat_map(move |excerpt| {
6553                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6554                if excerpt.id == range.start.excerpt_id {
6555                    query_range.start = range.start.text_anchor;
6556                }
6557                if excerpt.id == range.end.excerpt_id {
6558                    query_range.end = range.end.text_anchor;
6559                }
6560
6561                excerpt
6562                    .buffer
6563                    .selections_in_range(query_range, include_local)
6564                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6565                        selections.map(move |selection| {
6566                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6567                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6568                            if range.start.cmp(&start, self).is_gt() {
6569                                start = range.start;
6570                            }
6571                            if range.end.cmp(&end, self).is_lt() {
6572                                end = range.end;
6573                            }
6574
6575                            (
6576                                replica_id,
6577                                line_mode,
6578                                cursor_shape,
6579                                Selection {
6580                                    id: selection.id,
6581                                    start,
6582                                    end,
6583                                    reversed: selection.reversed,
6584                                    goal: selection.goal,
6585                                },
6586                            )
6587                        })
6588                    })
6589            })
6590    }
6591
6592    pub fn show_headers(&self) -> bool {
6593        self.show_headers
6594    }
6595
6596    /// Visually annotates a position or range with the `Debug` representation of a value. The
6597    /// callsite of this function is used as a key - previous annotations will be removed.
6598    #[cfg(debug_assertions)]
6599    #[track_caller]
6600    pub fn debug<V, R>(&self, ranges: &R, value: V)
6601    where
6602        R: debug::ToMultiBufferDebugRanges,
6603        V: std::fmt::Debug,
6604    {
6605        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6606    }
6607
6608    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6609    /// debug annotations with the same key will be removed. The key is also used to determine the
6610    /// annotation's color.
6611    #[cfg(debug_assertions)]
6612    #[track_caller]
6613    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6614    where
6615        K: std::hash::Hash + 'static,
6616        R: debug::ToMultiBufferDebugRanges,
6617        V: std::fmt::Debug,
6618    {
6619        let text_ranges = ranges
6620            .to_multi_buffer_debug_ranges(self)
6621            .into_iter()
6622            .flat_map(|range| {
6623                self.range_to_buffer_ranges(range).into_iter().map(
6624                    |(buffer, range, _excerpt_id)| {
6625                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6626                    },
6627                )
6628            })
6629            .collect();
6630        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6631            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6632        });
6633    }
6634}
6635
6636#[cfg(any(test, feature = "test-support"))]
6637impl MultiBufferSnapshot {
6638    pub fn random_byte_range(
6639        &self,
6640        start_offset: MultiBufferOffset,
6641        rng: &mut impl rand::Rng,
6642    ) -> Range<MultiBufferOffset> {
6643        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6644        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6645        start..end
6646    }
6647
6648    #[cfg(any(test, feature = "test-support"))]
6649    fn check_invariants(&self) {
6650        let excerpts = self.excerpts.items(());
6651        let excerpt_ids = self.excerpt_ids.items(());
6652
6653        for (ix, excerpt) in excerpts.iter().enumerate() {
6654            if ix == 0 {
6655                if excerpt.locator <= Locator::min() {
6656                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6657                }
6658            } else if excerpt.locator <= excerpts[ix - 1].locator {
6659                panic!("excerpts are out-of-order: {:?}", excerpts);
6660            }
6661        }
6662
6663        for (ix, entry) in excerpt_ids.iter().enumerate() {
6664            if ix == 0 {
6665                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6666                    panic!("invalid first excerpt id {:?}", entry.id);
6667                }
6668            } else if entry.id <= excerpt_ids[ix - 1].id {
6669                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6670            }
6671        }
6672
6673        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6674            panic!(
6675                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6676                self.excerpts.summary().text,
6677                self.diff_transforms.summary().input,
6678                self.diff_transforms.items(()),
6679            );
6680        }
6681
6682        let mut prev_transform: Option<&DiffTransform> = None;
6683        for item in self.diff_transforms.iter() {
6684            if let DiffTransform::BufferContent {
6685                summary,
6686                inserted_hunk_info,
6687            } = item
6688            {
6689                if let Some(DiffTransform::BufferContent {
6690                    inserted_hunk_info: prev_inserted_hunk_info,
6691                    ..
6692                }) = prev_transform
6693                    && *inserted_hunk_info == *prev_inserted_hunk_info
6694                {
6695                    panic!(
6696                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6697                        self.diff_transforms.items(())
6698                    );
6699                }
6700                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6701                    panic!("empty buffer content transform");
6702                }
6703            }
6704            prev_transform = Some(item);
6705        }
6706    }
6707}
6708
6709impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6710where
6711    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6712    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6713{
6714    fn seek(&mut self, position: &MBD) {
6715        let position = OutputDimension(*position);
6716        self.cached_region.take();
6717        self.diff_transforms.seek(&position, Bias::Right);
6718        if self.diff_transforms.item().is_none()
6719            && self.diff_transforms.start().output_dimension == position
6720        {
6721            self.diff_transforms.prev();
6722        }
6723
6724        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6725        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6726            let overshoot = position - self.diff_transforms.start().output_dimension;
6727            excerpt_position += overshoot;
6728        }
6729
6730        self.excerpts.seek(&excerpt_position, Bias::Right);
6731        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6732            self.excerpts.prev();
6733        }
6734    }
6735
6736    fn seek_forward(&mut self, position: &MBD) {
6737        let position = OutputDimension(*position);
6738        self.cached_region.take();
6739        self.diff_transforms.seek_forward(&position, Bias::Right);
6740        if self.diff_transforms.item().is_none()
6741            && self.diff_transforms.start().output_dimension == position
6742        {
6743            self.diff_transforms.prev();
6744        }
6745
6746        let overshoot = position - self.diff_transforms.start().output_dimension;
6747        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6748        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6749            excerpt_position += overshoot;
6750        }
6751
6752        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6753        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6754            self.excerpts.prev();
6755        }
6756    }
6757
6758    fn next_excerpt(&mut self) {
6759        self.excerpts.next();
6760        self.seek_to_start_of_current_excerpt();
6761    }
6762
6763    fn prev_excerpt(&mut self) {
6764        self.excerpts.prev();
6765        self.seek_to_start_of_current_excerpt();
6766    }
6767
6768    fn seek_to_start_of_current_excerpt(&mut self) {
6769        self.cached_region.take();
6770        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6771        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6772            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6773            && self.diff_transforms.next_item().is_some()
6774        {
6775            self.diff_transforms.next();
6776        }
6777    }
6778
6779    fn next(&mut self) {
6780        self.cached_region.take();
6781        match self
6782            .diff_transforms
6783            .end()
6784            .excerpt_dimension
6785            .cmp(&self.excerpts.end())
6786        {
6787            cmp::Ordering::Less => self.diff_transforms.next(),
6788            cmp::Ordering::Greater => self.excerpts.next(),
6789            cmp::Ordering::Equal => {
6790                self.diff_transforms.next();
6791                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6792                    || self.diff_transforms.item().is_none()
6793                {
6794                    self.excerpts.next();
6795                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6796                    self.diff_transforms.item()
6797                    && self
6798                        .excerpts
6799                        .item()
6800                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6801                {
6802                    self.excerpts.next();
6803                }
6804            }
6805        }
6806    }
6807
6808    fn prev(&mut self) {
6809        self.cached_region.take();
6810        match self
6811            .diff_transforms
6812            .start()
6813            .excerpt_dimension
6814            .cmp(self.excerpts.start())
6815        {
6816            cmp::Ordering::Less => self.excerpts.prev(),
6817            cmp::Ordering::Greater => self.diff_transforms.prev(),
6818            cmp::Ordering::Equal => {
6819                self.diff_transforms.prev();
6820                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6821                    || self.diff_transforms.item().is_none()
6822                {
6823                    self.excerpts.prev();
6824                }
6825            }
6826        }
6827    }
6828
6829    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6830        if self.cached_region.is_none() {
6831            self.cached_region = self.build_region();
6832        }
6833        self.cached_region.clone()
6834    }
6835
6836    fn is_at_start_of_excerpt(&mut self) -> bool {
6837        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6838            return false;
6839        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6840            return true;
6841        }
6842
6843        self.diff_transforms.prev();
6844        let prev_transform = self.diff_transforms.item();
6845        self.diff_transforms.next();
6846
6847        prev_transform.is_none_or(|next_transform| {
6848            matches!(next_transform, DiffTransform::BufferContent { .. })
6849        })
6850    }
6851
6852    fn is_at_end_of_excerpt(&mut self) -> bool {
6853        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6854            return false;
6855        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6856            || self.diff_transforms.item().is_none()
6857        {
6858            return true;
6859        }
6860
6861        let next_transform = self.diff_transforms.next_item();
6862        next_transform.is_none_or(|next_transform| match next_transform {
6863            DiffTransform::BufferContent { .. } => true,
6864            DiffTransform::DeletedHunk { hunk_info, .. } => self
6865                .excerpts
6866                .item()
6867                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6868        })
6869    }
6870
6871    fn main_buffer_position(&self) -> Option<BD> {
6872        let excerpt = self.excerpts.item()?;
6873        let buffer = &excerpt.buffer;
6874        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6875        let mut buffer_start = buffer_context_start;
6876        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6877        buffer_start += overshoot;
6878        Some(buffer_start)
6879    }
6880
6881    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6882        let excerpt = self.excerpts.item()?;
6883        match self.diff_transforms.item()? {
6884            DiffTransform::DeletedHunk {
6885                buffer_id,
6886                base_text_byte_range,
6887                has_trailing_newline,
6888                hunk_info,
6889                ..
6890            } => {
6891                let diff = self.diffs.get(buffer_id)?;
6892                let buffer = diff.base_text();
6893                let mut rope_cursor = buffer.as_rope().cursor(0);
6894                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6895                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6896                let mut buffer_end = buffer_start;
6897                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6898                let start = self.diff_transforms.start().output_dimension.0;
6899                let end = self.diff_transforms.end().output_dimension.0;
6900                Some(MultiBufferRegion {
6901                    buffer,
6902                    excerpt,
6903                    has_trailing_newline: *has_trailing_newline,
6904                    is_main_buffer: false,
6905                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6906                        hunk_info.hunk_secondary_status,
6907                    )),
6908                    buffer_range: buffer_start..buffer_end,
6909                    range: start..end,
6910                })
6911            }
6912            DiffTransform::BufferContent {
6913                inserted_hunk_info, ..
6914            } => {
6915                let buffer = &excerpt.buffer;
6916                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6917
6918                let mut start = self.diff_transforms.start().output_dimension.0;
6919                let mut buffer_start = buffer_context_start;
6920                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6921                    let overshoot =
6922                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6923                    start += overshoot;
6924                } else {
6925                    let overshoot =
6926                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6927                    buffer_start += overshoot;
6928                }
6929
6930                let mut end;
6931                let mut buffer_end;
6932                let has_trailing_newline;
6933                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6934                    let overshoot =
6935                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6936                    end = self.diff_transforms.end().output_dimension.0;
6937                    buffer_end = buffer_context_start;
6938                    buffer_end += overshoot;
6939                    has_trailing_newline = false;
6940                } else {
6941                    let overshoot =
6942                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6943                    end = self.diff_transforms.start().output_dimension.0;
6944                    end += overshoot;
6945                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6946                    has_trailing_newline = excerpt.has_trailing_newline;
6947                };
6948
6949                let diff_hunk_status = inserted_hunk_info.map(|info| {
6950                    if info.is_logically_deleted {
6951                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6952                    } else {
6953                        DiffHunkStatus::added(info.hunk_secondary_status)
6954                    }
6955                });
6956
6957                Some(MultiBufferRegion {
6958                    buffer,
6959                    excerpt,
6960                    has_trailing_newline,
6961                    is_main_buffer: true,
6962                    diff_hunk_status,
6963                    buffer_range: buffer_start..buffer_end,
6964                    range: start..end,
6965                })
6966            }
6967        }
6968    }
6969
6970    fn excerpt(&self) -> Option<&'a Excerpt> {
6971        self.excerpts.item()
6972    }
6973}
6974
6975impl Excerpt {
6976    fn new(
6977        id: ExcerptId,
6978        locator: Locator,
6979        buffer_id: BufferId,
6980        buffer: BufferSnapshot,
6981        range: ExcerptRange<text::Anchor>,
6982        has_trailing_newline: bool,
6983    ) -> Self {
6984        Excerpt {
6985            id,
6986            locator,
6987            max_buffer_row: range.context.end.to_point(&buffer).row,
6988            text_summary: buffer
6989                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6990            buffer_id,
6991            buffer,
6992            range,
6993            has_trailing_newline,
6994        }
6995    }
6996
6997    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6998        let content_start = self.range.context.start.to_offset(&self.buffer);
6999        let chunks_start = content_start + range.start;
7000        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7001
7002        let has_footer = self.has_trailing_newline
7003            && range.start <= self.text_summary.len
7004            && range.end > self.text_summary.len;
7005
7006        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7007
7008        ExcerptChunks {
7009            excerpt_id: self.id,
7010            content_chunks,
7011            has_footer,
7012        }
7013    }
7014
7015    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7016        let content_start = self.range.context.start.to_offset(&self.buffer);
7017        let chunks_start = content_start + range.start;
7018        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7019        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7020        excerpt_chunks.has_footer = self.has_trailing_newline
7021            && range.start <= self.text_summary.len
7022            && range.end > self.text_summary.len;
7023    }
7024
7025    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7026        if text_anchor
7027            .cmp(&self.range.context.start, &self.buffer)
7028            .is_lt()
7029        {
7030            self.range.context.start
7031        } else if text_anchor
7032            .cmp(&self.range.context.end, &self.buffer)
7033            .is_gt()
7034        {
7035            self.range.context.end
7036        } else {
7037            text_anchor
7038        }
7039    }
7040
7041    fn contains(&self, anchor: &Anchor) -> bool {
7042        (anchor.text_anchor.buffer_id == None
7043            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7044            && self
7045                .range
7046                .context
7047                .start
7048                .cmp(&anchor.text_anchor, &self.buffer)
7049                .is_le()
7050            && self
7051                .range
7052                .context
7053                .end
7054                .cmp(&anchor.text_anchor, &self.buffer)
7055                .is_ge()
7056    }
7057
7058    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7059    fn buffer_start_offset(&self) -> BufferOffset {
7060        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7061    }
7062
7063    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7064    fn buffer_end_offset(&self) -> BufferOffset {
7065        self.buffer_start_offset() + self.text_summary.len
7066    }
7067}
7068
7069impl<'a> MultiBufferExcerpt<'a> {
7070    pub fn id(&self) -> ExcerptId {
7071        self.excerpt.id
7072    }
7073
7074    pub fn buffer_id(&self) -> BufferId {
7075        self.excerpt.buffer_id
7076    }
7077
7078    pub fn start_anchor(&self) -> Anchor {
7079        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7080    }
7081
7082    pub fn end_anchor(&self) -> Anchor {
7083        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7084    }
7085
7086    pub fn buffer(&self) -> &'a BufferSnapshot {
7087        &self.excerpt.buffer
7088    }
7089
7090    pub fn buffer_range(&self) -> Range<BufferOffset> {
7091        self.buffer_offset
7092            ..BufferOffset(
7093                self.excerpt
7094                    .range
7095                    .context
7096                    .end
7097                    .to_offset(&self.excerpt.buffer.text),
7098            )
7099    }
7100
7101    pub fn start_offset(&self) -> MultiBufferOffset {
7102        self.offset
7103    }
7104
7105    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7106    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7107        self.map_range_to_buffer(offset..offset).start
7108    }
7109
7110    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7111    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7112        self.diff_transforms
7113            .seek(&OutputDimension(range.start), Bias::Right);
7114        let start = self.map_offset_to_buffer_internal(range.start);
7115        let end = if range.end > range.start {
7116            self.diff_transforms
7117                .seek_forward(&OutputDimension(range.end), Bias::Right);
7118            self.map_offset_to_buffer_internal(range.end)
7119        } else {
7120            start
7121        };
7122        start..end
7123    }
7124
7125    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7126        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7127        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7128            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7129        };
7130        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7131        self.buffer_offset + offset_in_excerpt
7132    }
7133
7134    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7135    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7136        self.map_range_from_buffer(buffer_offset..buffer_offset)
7137            .start
7138    }
7139
7140    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7141    pub fn map_range_from_buffer(
7142        &mut self,
7143        buffer_range: Range<BufferOffset>,
7144    ) -> Range<MultiBufferOffset> {
7145        if buffer_range.start < self.buffer_offset {
7146            log::warn!(
7147                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7148            );
7149            return self.offset..self.offset;
7150        }
7151        let overshoot = buffer_range.start - self.buffer_offset;
7152        let excerpt_offset = self.excerpt_offset + overshoot;
7153        let excerpt_seek_dim = excerpt_offset;
7154        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7155        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7156            log::warn!(
7157                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7158            );
7159            return self.offset..self.offset;
7160        }
7161        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7162        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7163
7164        let end = if buffer_range.start < buffer_range.end {
7165            let overshoot = buffer_range.end - self.buffer_offset;
7166            let excerpt_offset = self.excerpt_offset + overshoot;
7167            let excerpt_seek_dim = excerpt_offset;
7168            self.diff_transforms
7169                .seek_forward(&excerpt_seek_dim, Bias::Right);
7170            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7171            // todo(lw): Clamp end to the excerpt boundaries
7172            self.diff_transforms.start().output_dimension.0 + overshoot
7173        } else {
7174            start
7175        };
7176
7177        start..end
7178    }
7179
7180    /// Returns true if the entirety of the given range is in the buffer's excerpt
7181    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7182        range.start >= self.excerpt.buffer_start_offset()
7183            && range.end <= self.excerpt.buffer_end_offset()
7184    }
7185
7186    pub fn max_buffer_row(&self) -> u32 {
7187        self.excerpt.max_buffer_row
7188    }
7189}
7190
7191impl ExcerptId {
7192    pub fn min() -> Self {
7193        Self(0)
7194    }
7195
7196    pub fn max() -> Self {
7197        Self(u32::MAX)
7198    }
7199
7200    pub fn to_proto(self) -> u64 {
7201        self.0 as _
7202    }
7203
7204    pub fn from_proto(proto: u64) -> Self {
7205        Self(proto as _)
7206    }
7207
7208    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7209        let a = snapshot.excerpt_locator_for_id(*self);
7210        let b = snapshot.excerpt_locator_for_id(*other);
7211        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7212    }
7213}
7214
7215impl From<ExcerptId> for usize {
7216    fn from(val: ExcerptId) -> Self {
7217        val.0 as usize
7218    }
7219}
7220
7221impl fmt::Debug for Excerpt {
7222    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7223        f.debug_struct("Excerpt")
7224            .field("id", &self.id)
7225            .field("locator", &self.locator)
7226            .field("buffer_id", &self.buffer_id)
7227            .field("range", &self.range)
7228            .field("text_summary", &self.text_summary)
7229            .field("has_trailing_newline", &self.has_trailing_newline)
7230            .finish()
7231    }
7232}
7233
7234impl sum_tree::Item for Excerpt {
7235    type Summary = ExcerptSummary;
7236
7237    fn summary(&self, _cx: ()) -> Self::Summary {
7238        let mut text = self.text_summary;
7239        if self.has_trailing_newline {
7240            text += TextSummary::from("\n");
7241        }
7242        ExcerptSummary {
7243            excerpt_id: self.id,
7244            excerpt_locator: self.locator.clone(),
7245            widest_line_number: self.max_buffer_row,
7246            text: text.into(),
7247        }
7248    }
7249}
7250
7251impl sum_tree::Item for ExcerptIdMapping {
7252    type Summary = ExcerptId;
7253
7254    fn summary(&self, _cx: ()) -> Self::Summary {
7255        self.id
7256    }
7257}
7258
7259impl sum_tree::KeyedItem for ExcerptIdMapping {
7260    type Key = ExcerptId;
7261
7262    fn key(&self) -> Self::Key {
7263        self.id
7264    }
7265}
7266
7267impl DiffTransform {
7268    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7269        match self {
7270            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7271            DiffTransform::BufferContent {
7272                inserted_hunk_info, ..
7273            } => *inserted_hunk_info,
7274        }
7275    }
7276}
7277
7278impl sum_tree::Item for DiffTransform {
7279    type Summary = DiffTransformSummary;
7280
7281    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7282        match self {
7283            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7284                input: *summary,
7285                output: *summary,
7286            },
7287            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7288                input: MBTextSummary::default(),
7289                output: summary.into(),
7290            },
7291        }
7292    }
7293}
7294
7295impl DiffTransformSummary {
7296    fn excerpt_len(&self) -> ExcerptOffset {
7297        ExcerptDimension(self.input.len)
7298    }
7299}
7300
7301impl sum_tree::ContextLessSummary for DiffTransformSummary {
7302    fn zero() -> Self {
7303        DiffTransformSummary {
7304            input: MBTextSummary::default(),
7305            output: MBTextSummary::default(),
7306        }
7307    }
7308
7309    fn add_summary(&mut self, other: &Self) {
7310        self.input += other.input;
7311        self.output += other.output;
7312    }
7313}
7314
7315impl sum_tree::ContextLessSummary for ExcerptId {
7316    fn zero() -> Self {
7317        Self(0)
7318    }
7319
7320    fn add_summary(&mut self, summary: &Self) {
7321        *self = cmp::max(*self, *summary);
7322    }
7323}
7324
7325impl sum_tree::ContextLessSummary for ExcerptSummary {
7326    fn zero() -> Self {
7327        Self::default()
7328    }
7329
7330    fn add_summary(&mut self, summary: &Self) {
7331        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7332        self.excerpt_locator = summary.excerpt_locator.clone();
7333        self.text += summary.text;
7334        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7335    }
7336}
7337
7338impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7339    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7340        Ord::cmp(&Some(self), cursor_location)
7341    }
7342}
7343
7344impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7345    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7346        Ord::cmp(self, &cursor_location.excerpt_locator)
7347    }
7348}
7349
7350impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7351where
7352    MBD: MultiBufferDimension + Default,
7353{
7354    fn zero(_: ()) -> Self {
7355        ExcerptDimension(MBD::default())
7356    }
7357
7358    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7359        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7360    }
7361}
7362
7363impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7364    fn zero(_cx: ()) -> Self {
7365        Default::default()
7366    }
7367
7368    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7369        *self = Some(&summary.excerpt_locator);
7370    }
7371}
7372
7373impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7374    fn zero(_cx: ()) -> Self {
7375        Default::default()
7376    }
7377
7378    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7379        *self = Some(summary.excerpt_id);
7380    }
7381}
7382
7383#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7384struct OutputDimension<T>(T);
7385
7386impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7387    fn eq(&self, other: &T) -> bool {
7388        self.0 == *other
7389    }
7390}
7391
7392impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7393    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7394        self.0.partial_cmp(other)
7395    }
7396}
7397
7398impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7399where
7400    T: ops::Sub<U, Output = R>,
7401{
7402    type Output = R;
7403
7404    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7405        self.0 - other.0
7406    }
7407}
7408
7409impl<R, T, U> ops::Add<U> for OutputDimension<T>
7410where
7411    T: ops::Add<U, Output = R>,
7412{
7413    type Output = OutputDimension<R>;
7414
7415    fn add(self, other: U) -> Self::Output {
7416        OutputDimension(self.0 + other)
7417    }
7418}
7419
7420impl<T, U> AddAssign<U> for OutputDimension<T>
7421where
7422    T: AddAssign<U>,
7423{
7424    fn add_assign(&mut self, other: U) {
7425        self.0 += other;
7426    }
7427}
7428
7429impl<T, U> SubAssign<U> for OutputDimension<T>
7430where
7431    T: SubAssign<U>,
7432{
7433    fn sub_assign(&mut self, other: U) {
7434        self.0 -= other;
7435    }
7436}
7437
7438#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7439struct ExcerptDimension<T>(T);
7440
7441impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7442    fn eq(&self, other: &T) -> bool {
7443        self.0 == *other
7444    }
7445}
7446
7447impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7448    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7449        self.0.partial_cmp(other)
7450    }
7451}
7452
7453impl ExcerptOffset {
7454    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7455        self.0.saturating_sub(other.0)
7456    }
7457}
7458
7459impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7460where
7461    T: ops::Sub<U, Output = R>,
7462{
7463    type Output = R;
7464
7465    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7466        self.0 - other.0
7467    }
7468}
7469
7470impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7471where
7472    T: ops::Add<U, Output = R>,
7473{
7474    type Output = ExcerptDimension<R>;
7475
7476    fn add(self, other: U) -> Self::Output {
7477        ExcerptDimension(self.0 + other)
7478    }
7479}
7480
7481impl<T, U> AddAssign<U> for ExcerptDimension<T>
7482where
7483    T: AddAssign<U>,
7484{
7485    fn add_assign(&mut self, other: U) {
7486        self.0 += other;
7487    }
7488}
7489
7490impl<T, U> SubAssign<U> for ExcerptDimension<T>
7491where
7492    T: SubAssign<U>,
7493{
7494    fn sub_assign(&mut self, other: U) {
7495        self.0 -= other;
7496    }
7497}
7498
7499impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7500    fn zero(_: ()) -> Self {
7501        MultiBufferOffset::ZERO
7502    }
7503
7504    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7505        *self += summary.output.len;
7506    }
7507}
7508
7509impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7510    for ExcerptDimension<MBD>
7511where
7512    MBD: MultiBufferDimension + Ord,
7513{
7514    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7515        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7516    }
7517}
7518
7519impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7520    for ExcerptDimension<MBD>
7521where
7522    MBD: MultiBufferDimension + Ord,
7523{
7524    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7525        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7526    }
7527}
7528
7529impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7530    for ExcerptDimension<MBD>
7531{
7532    fn zero(_: ()) -> Self {
7533        ExcerptDimension(MBD::default())
7534    }
7535
7536    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7537        self.0.add_mb_text_summary(&summary.input)
7538    }
7539}
7540
7541impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7542    for OutputDimension<MBD>
7543where
7544    MBD: MultiBufferDimension + Ord,
7545{
7546    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7547        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7548    }
7549}
7550
7551impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7552    for OutputDimension<MBD>
7553{
7554    fn zero(_: ()) -> Self {
7555        OutputDimension(MBD::default())
7556    }
7557
7558    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7559        self.0.add_mb_text_summary(&summary.output)
7560    }
7561}
7562
7563impl MultiBufferRows<'_> {
7564    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7565        self.point = Point::new(row, 0);
7566        self.cursor.seek(&self.point);
7567    }
7568}
7569
7570impl Iterator for MultiBufferRows<'_> {
7571    type Item = RowInfo;
7572
7573    fn next(&mut self) -> Option<Self::Item> {
7574        if self.is_empty && self.point.row == 0 {
7575            self.point += Point::new(1, 0);
7576            return Some(RowInfo {
7577                buffer_id: None,
7578                buffer_row: Some(0),
7579                multibuffer_row: Some(MultiBufferRow(0)),
7580                diff_status: None,
7581                expand_info: None,
7582                wrapped_buffer_row: None,
7583            });
7584        }
7585
7586        let mut region = self.cursor.region()?;
7587        while self.point >= region.range.end {
7588            self.cursor.next();
7589            if let Some(next_region) = self.cursor.region() {
7590                region = next_region;
7591            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7592                let multibuffer_row = MultiBufferRow(self.point.row);
7593                let last_excerpt = self
7594                    .cursor
7595                    .excerpts
7596                    .item()
7597                    .or(self.cursor.excerpts.prev_item())?;
7598                let last_row = last_excerpt
7599                    .range
7600                    .context
7601                    .end
7602                    .to_point(&last_excerpt.buffer)
7603                    .row;
7604
7605                let first_row = last_excerpt
7606                    .range
7607                    .context
7608                    .start
7609                    .to_point(&last_excerpt.buffer)
7610                    .row;
7611
7612                let expand_info = if self.is_singleton {
7613                    None
7614                } else {
7615                    let needs_expand_up = first_row == last_row
7616                        && last_row > 0
7617                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7618                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7619
7620                    if needs_expand_up && needs_expand_down {
7621                        Some(ExpandExcerptDirection::UpAndDown)
7622                    } else if needs_expand_up {
7623                        Some(ExpandExcerptDirection::Up)
7624                    } else if needs_expand_down {
7625                        Some(ExpandExcerptDirection::Down)
7626                    } else {
7627                        None
7628                    }
7629                    .map(|direction| ExpandInfo {
7630                        direction,
7631                        excerpt_id: last_excerpt.id,
7632                    })
7633                };
7634                self.point += Point::new(1, 0);
7635                return Some(RowInfo {
7636                    buffer_id: Some(last_excerpt.buffer_id),
7637                    buffer_row: Some(last_row),
7638                    multibuffer_row: Some(multibuffer_row),
7639                    diff_status: None,
7640                    wrapped_buffer_row: None,
7641                    expand_info,
7642                });
7643            } else {
7644                return None;
7645            };
7646        }
7647
7648        let overshoot = self.point - region.range.start;
7649        let buffer_point = region.buffer_range.start + overshoot;
7650        let expand_info = if self.is_singleton {
7651            None
7652        } else {
7653            let needs_expand_up = self.point.row == region.range.start.row
7654                && self.cursor.is_at_start_of_excerpt()
7655                && buffer_point.row > 0;
7656            let needs_expand_down = (region.excerpt.has_trailing_newline
7657                && self.point.row + 1 == region.range.end.row
7658                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7659                && self.cursor.is_at_end_of_excerpt()
7660                && buffer_point.row < region.buffer.max_point().row;
7661
7662            if needs_expand_up && needs_expand_down {
7663                Some(ExpandExcerptDirection::UpAndDown)
7664            } else if needs_expand_up {
7665                Some(ExpandExcerptDirection::Up)
7666            } else if needs_expand_down {
7667                Some(ExpandExcerptDirection::Down)
7668            } else {
7669                None
7670            }
7671            .map(|direction| ExpandInfo {
7672                direction,
7673                excerpt_id: region.excerpt.id,
7674            })
7675        };
7676
7677        let result = Some(RowInfo {
7678            buffer_id: Some(region.buffer.remote_id()),
7679            buffer_row: Some(buffer_point.row),
7680            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7681            diff_status: region
7682                .diff_hunk_status
7683                .filter(|_| self.point < region.range.end),
7684            expand_info,
7685            wrapped_buffer_row: None,
7686        });
7687        self.point += Point::new(1, 0);
7688        result
7689    }
7690}
7691
7692impl<'a> MultiBufferChunks<'a> {
7693    pub fn offset(&self) -> MultiBufferOffset {
7694        self.range.start
7695    }
7696
7697    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7698        self.diff_transforms.seek(&range.end, Bias::Right);
7699        let mut excerpt_end = self.diff_transforms.start().1;
7700        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7701            let overshoot = range.end - self.diff_transforms.start().0;
7702            excerpt_end += overshoot;
7703        }
7704
7705        self.diff_transforms.seek(&range.start, Bias::Right);
7706        let mut excerpt_start = self.diff_transforms.start().1;
7707        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7708            let overshoot = range.start - self.diff_transforms.start().0;
7709            excerpt_start += overshoot;
7710        }
7711
7712        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7713        self.buffer_chunk.take();
7714        self.range = range;
7715    }
7716
7717    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7718        self.excerpt_offset_range = new_range.clone();
7719        self.excerpts.seek(&new_range.start, Bias::Right);
7720        if let Some(excerpt) = self.excerpts.item() {
7721            let excerpt_start = *self.excerpts.start();
7722            if let Some(excerpt_chunks) = self
7723                .excerpt_chunks
7724                .as_mut()
7725                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7726            {
7727                excerpt.seek_chunks(
7728                    excerpt_chunks,
7729                    (self.excerpt_offset_range.start - excerpt_start)
7730                        ..(self.excerpt_offset_range.end - excerpt_start),
7731                );
7732            } else {
7733                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7734                    (self.excerpt_offset_range.start - excerpt_start)
7735                        ..(self.excerpt_offset_range.end - excerpt_start),
7736                    self.language_aware,
7737                ));
7738            }
7739        } else {
7740            self.excerpt_chunks = None;
7741        }
7742    }
7743
7744    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7745        loop {
7746            if self.excerpt_offset_range.is_empty() {
7747                return None;
7748            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7749                self.excerpt_offset_range.start += chunk.text.len();
7750                return Some(chunk);
7751            } else {
7752                self.excerpts.next();
7753                let excerpt = self.excerpts.item()?;
7754                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7755                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7756                    self.language_aware,
7757                ));
7758            }
7759        }
7760    }
7761}
7762
7763impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7764    type Item = &'a str;
7765
7766    fn next(&mut self) -> Option<Self::Item> {
7767        let mut region = self.cursor.region()?;
7768        if self.offset == region.range.start {
7769            self.cursor.prev();
7770            region = self.cursor.region()?;
7771            let start_overshoot = self.start.saturating_sub(region.range.start);
7772            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7773                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7774            ));
7775        }
7776
7777        if self.offset == region.range.end && region.has_trailing_newline {
7778            self.offset -= 1;
7779            Some("\n")
7780        } else {
7781            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7782            self.offset -= chunk.len();
7783            Some(chunk)
7784        }
7785    }
7786}
7787
7788impl<'a> Iterator for MultiBufferChunks<'a> {
7789    type Item = Chunk<'a>;
7790
7791    fn next(&mut self) -> Option<Chunk<'a>> {
7792        if self.range.start >= self.range.end {
7793            return None;
7794        }
7795        if self.range.start == self.diff_transforms.end().0 {
7796            self.diff_transforms.next();
7797        }
7798
7799        let diff_transform_start = self.diff_transforms.start().0;
7800        let diff_transform_end = self.diff_transforms.end().0;
7801        debug_assert!(
7802            self.range.start < diff_transform_end,
7803            "{:?} < {:?} of ({1:?}..{2:?})",
7804            self.range.start,
7805            diff_transform_end,
7806            diff_transform_start
7807        );
7808
7809        let diff_transform = self.diff_transforms.item()?;
7810        match diff_transform {
7811            DiffTransform::BufferContent { .. } => {
7812                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7813                    chunk
7814                } else {
7815                    let chunk = self.next_excerpt_chunk().unwrap();
7816                    self.buffer_chunk.insert(chunk)
7817                };
7818
7819                let chunk_end = self.range.start + chunk.text.len();
7820                let diff_transform_end = diff_transform_end.min(self.range.end);
7821
7822                if diff_transform_end < chunk_end {
7823                    let split_idx = diff_transform_end - self.range.start;
7824                    let (before, after) = chunk.text.split_at(split_idx);
7825                    self.range.start = diff_transform_end;
7826                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7827                    let chars = chunk.chars & mask;
7828                    let tabs = chunk.tabs & mask;
7829
7830                    chunk.text = after;
7831                    chunk.chars = chunk.chars >> split_idx;
7832                    chunk.tabs = chunk.tabs >> split_idx;
7833
7834                    Some(Chunk {
7835                        text: before,
7836                        chars,
7837                        tabs,
7838                        ..chunk.clone()
7839                    })
7840                } else {
7841                    self.range.start = chunk_end;
7842                    self.buffer_chunk.take()
7843                }
7844            }
7845            DiffTransform::DeletedHunk {
7846                buffer_id,
7847                base_text_byte_range,
7848                has_trailing_newline,
7849                ..
7850            } => {
7851                let base_text_start =
7852                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7853                let base_text_end =
7854                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7855                let base_text_end = base_text_end.min(base_text_byte_range.end);
7856
7857                let mut chunks = if let Some((_, mut chunks)) = self
7858                    .diff_base_chunks
7859                    .take()
7860                    .filter(|(id, _)| id == buffer_id)
7861                {
7862                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7863                    {
7864                        chunks.seek(base_text_start..base_text_end);
7865                    }
7866                    chunks
7867                } else {
7868                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7869                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7870                };
7871
7872                let chunk = if let Some(chunk) = chunks.next() {
7873                    self.range.start += chunk.text.len();
7874                    self.diff_base_chunks = Some((*buffer_id, chunks));
7875                    chunk
7876                } else {
7877                    debug_assert!(has_trailing_newline);
7878                    self.range.start += "\n".len();
7879                    Chunk {
7880                        text: "\n",
7881                        chars: 1u128,
7882                        ..Default::default()
7883                    }
7884                };
7885                Some(chunk)
7886            }
7887        }
7888    }
7889}
7890
7891impl MultiBufferBytes<'_> {
7892    fn consume(&mut self, len: usize) {
7893        self.range.start += len;
7894        self.chunk = &self.chunk[len..];
7895
7896        if !self.range.is_empty() && self.chunk.is_empty() {
7897            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7898                self.chunk = chunk;
7899            } else if self.has_trailing_newline {
7900                self.has_trailing_newline = false;
7901                self.chunk = b"\n";
7902            } else {
7903                self.cursor.next();
7904                if let Some(region) = self.cursor.region() {
7905                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7906                        region.buffer_range.start
7907                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7908                                .min(region.buffer_range.end),
7909                    );
7910                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7911                    self.excerpt_bytes = Some(excerpt_bytes);
7912                    self.has_trailing_newline =
7913                        region.has_trailing_newline && self.range.end >= region.range.end;
7914                    if self.chunk.is_empty() && self.has_trailing_newline {
7915                        self.has_trailing_newline = false;
7916                        self.chunk = b"\n";
7917                    }
7918                }
7919            }
7920        }
7921    }
7922}
7923
7924impl<'a> Iterator for MultiBufferBytes<'a> {
7925    type Item = &'a [u8];
7926
7927    fn next(&mut self) -> Option<Self::Item> {
7928        let chunk = self.chunk;
7929        if chunk.is_empty() {
7930            None
7931        } else {
7932            self.consume(chunk.len());
7933            Some(chunk)
7934        }
7935    }
7936}
7937
7938impl io::Read for MultiBufferBytes<'_> {
7939    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7940        let len = cmp::min(buf.len(), self.chunk.len());
7941        buf[..len].copy_from_slice(&self.chunk[..len]);
7942        if len > 0 {
7943            self.consume(len);
7944        }
7945        Ok(len)
7946    }
7947}
7948
7949impl io::Read for ReversedMultiBufferBytes<'_> {
7950    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7951        let len = cmp::min(buf.len(), self.chunk.len());
7952        buf[..len].copy_from_slice(&self.chunk[..len]);
7953        buf[..len].reverse();
7954        if len > 0 {
7955            self.range.end -= len;
7956            self.chunk = &self.chunk[..self.chunk.len() - len];
7957            if !self.range.is_empty()
7958                && self.chunk.is_empty()
7959                && let Some(chunk) = self.chunks.next()
7960            {
7961                self.chunk = chunk.as_bytes();
7962            }
7963        }
7964        Ok(len)
7965    }
7966}
7967
7968impl<'a> Iterator for ExcerptChunks<'a> {
7969    type Item = Chunk<'a>;
7970
7971    fn next(&mut self) -> Option<Self::Item> {
7972        if let Some(chunk) = self.content_chunks.next() {
7973            return Some(chunk);
7974        }
7975
7976        if self.has_footer {
7977            let text = "\n";
7978            let chars = 0b1;
7979            self.has_footer = false;
7980            return Some(Chunk {
7981                text,
7982                chars,
7983                ..Default::default()
7984            });
7985        }
7986
7987        None
7988    }
7989}
7990
7991impl ToOffset for Point {
7992    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7993        snapshot.point_to_offset(*self)
7994    }
7995    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7996        snapshot.point_to_offset_utf16(*self)
7997    }
7998}
7999
8000impl ToOffset for MultiBufferOffset {
8001    #[track_caller]
8002    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8003        assert!(
8004            *self <= snapshot.len(),
8005            "offset {} is greater than the snapshot.len() {}",
8006            self.0,
8007            snapshot.len().0,
8008        );
8009        *self
8010    }
8011    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8012        snapshot.offset_to_offset_utf16(*self)
8013    }
8014}
8015
8016impl ToOffset for MultiBufferOffsetUtf16 {
8017    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8018        snapshot.offset_utf16_to_offset(*self)
8019    }
8020
8021    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8022        *self
8023    }
8024}
8025
8026impl ToOffset for PointUtf16 {
8027    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8028        snapshot.point_utf16_to_offset(*self)
8029    }
8030    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8031        snapshot.point_utf16_to_offset_utf16(*self)
8032    }
8033}
8034
8035impl ToPoint for MultiBufferOffset {
8036    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8037        snapshot.offset_to_point(*self)
8038    }
8039    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8040        snapshot.offset_to_point_utf16(*self)
8041    }
8042}
8043
8044impl ToPoint for Point {
8045    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8046        *self
8047    }
8048    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8049        snapshot.point_to_point_utf16(*self)
8050    }
8051}
8052
8053impl ToPoint for PointUtf16 {
8054    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8055        snapshot.point_utf16_to_point(*self)
8056    }
8057    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8058        *self
8059    }
8060}
8061
8062impl From<ExcerptId> for EntityId {
8063    fn from(id: ExcerptId) -> Self {
8064        EntityId::from(id.0 as u64)
8065    }
8066}
8067
8068#[cfg(debug_assertions)]
8069pub mod debug {
8070    use super::*;
8071
8072    pub trait ToMultiBufferDebugRanges {
8073        fn to_multi_buffer_debug_ranges(
8074            &self,
8075            snapshot: &MultiBufferSnapshot,
8076        ) -> Vec<Range<MultiBufferOffset>>;
8077    }
8078
8079    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8080        fn to_multi_buffer_debug_ranges(
8081            &self,
8082            snapshot: &MultiBufferSnapshot,
8083        ) -> Vec<Range<MultiBufferOffset>> {
8084            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8085        }
8086    }
8087
8088    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8089        fn to_multi_buffer_debug_ranges(
8090            &self,
8091            snapshot: &MultiBufferSnapshot,
8092        ) -> Vec<Range<MultiBufferOffset>> {
8093            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8094                .to_multi_buffer_debug_ranges(snapshot)
8095        }
8096    }
8097
8098    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8099        fn to_multi_buffer_debug_ranges(
8100            &self,
8101            snapshot: &MultiBufferSnapshot,
8102        ) -> Vec<Range<MultiBufferOffset>> {
8103            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8104        }
8105    }
8106
8107    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8108        fn to_multi_buffer_debug_ranges(
8109            &self,
8110            snapshot: &MultiBufferSnapshot,
8111        ) -> Vec<Range<MultiBufferOffset>> {
8112            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8113        }
8114    }
8115
8116    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8117        fn to_multi_buffer_debug_ranges(
8118            &self,
8119            snapshot: &MultiBufferSnapshot,
8120        ) -> Vec<Range<MultiBufferOffset>> {
8121            self.iter()
8122                .map(|item| {
8123                    let offset = item.to_offset(snapshot);
8124                    offset..offset
8125                })
8126                .collect()
8127        }
8128    }
8129
8130    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8131        fn to_multi_buffer_debug_ranges(
8132            &self,
8133            snapshot: &MultiBufferSnapshot,
8134        ) -> Vec<Range<MultiBufferOffset>> {
8135            self.iter()
8136                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8137                .collect()
8138        }
8139    }
8140}