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