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};
  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    is_inverted: bool,
 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            is_inverted: self.is_inverted,
 526        }
 527    }
 528}
 529
 530#[derive(Clone)]
 531struct DiffStateSnapshot {
 532    diff: BufferDiffSnapshot,
 533    is_inverted: bool,
 534}
 535
 536impl std::ops::Deref for DiffStateSnapshot {
 537    type Target = BufferDiffSnapshot;
 538
 539    fn deref(&self) -> &Self::Target {
 540        &self.diff
 541    }
 542}
 543
 544impl DiffState {
 545    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 546        DiffState {
 547            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 548                BufferDiffEvent::DiffChanged {
 549                    changed_range,
 550                    base_text_changed_range: _,
 551                } => {
 552                    if let Some(changed_range) = changed_range.clone() {
 553                        this.buffer_diff_changed(diff, changed_range, cx)
 554                    }
 555                    cx.emit(Event::BufferDiffChanged);
 556                }
 557                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 558                _ => {}
 559            }),
 560            diff,
 561            is_inverted: false,
 562        }
 563    }
 564
 565    fn new_inverted(
 566        diff: Entity<BufferDiff>,
 567        base_text_buffer_id: BufferId,
 568        cx: &mut Context<MultiBuffer>,
 569    ) -> Self {
 570        DiffState {
 571            _subscription: cx.subscribe(&diff, move |this, diff, event, cx| match event {
 572                BufferDiffEvent::DiffChanged {
 573                    changed_range: _,
 574                    base_text_changed_range,
 575                } => {
 576                    if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 577                        this.inverted_buffer_diff_changed(
 578                            diff,
 579                            base_text_changed_range,
 580                            base_text_buffer_id,
 581                            cx,
 582                        )
 583                    }
 584                    cx.emit(Event::BufferDiffChanged);
 585                }
 586                // FIXME
 587                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 588                _ => {}
 589            }),
 590            diff,
 591            is_inverted: true,
 592        }
 593    }
 594}
 595
 596/// The contents of a [`MultiBuffer`] at a single point in time.
 597#[derive(Clone, Default)]
 598pub struct MultiBufferSnapshot {
 599    excerpts: SumTree<Excerpt>,
 600    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 601    diff_transforms: SumTree<DiffTransform>,
 602    non_text_state_update_count: usize,
 603    edit_count: usize,
 604    is_dirty: bool,
 605    has_deleted_file: bool,
 606    has_conflict: bool,
 607    /// immutable fields
 608    singleton: bool,
 609    excerpt_ids: SumTree<ExcerptIdMapping>,
 610    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 611    trailing_excerpt_update_count: usize,
 612    all_diff_hunks_expanded: bool,
 613    show_deleted_hunks: bool,
 614    show_headers: bool,
 615}
 616
 617// follower: None
 618// - BufferContent(Some)
 619// - BufferContent(None)
 620// - DeletedHunk
 621//
 622// follower: Some
 623// - BufferContent(Some)
 624// - BufferContent(None)
 625
 626#[derive(Debug, Clone)]
 627enum DiffTransform {
 628    // RealText
 629    BufferContent {
 630        summary: MBTextSummary,
 631        // modified_hunk_info
 632        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 633    },
 634    // ExpandedHunkText
 635    DeletedHunk {
 636        summary: TextSummary,
 637        buffer_id: BufferId,
 638        hunk_info: DiffTransformHunkInfo,
 639        base_text_byte_range: Range<usize>,
 640        has_trailing_newline: bool,
 641    },
 642}
 643
 644#[derive(Clone, Copy, Debug)]
 645struct DiffTransformHunkInfo {
 646    excerpt_id: ExcerptId,
 647    hunk_start_anchor: text::Anchor,
 648    hunk_secondary_status: DiffHunkSecondaryStatus,
 649}
 650
 651impl Eq for DiffTransformHunkInfo {}
 652
 653impl PartialEq for DiffTransformHunkInfo {
 654    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 655        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 656    }
 657}
 658
 659impl std::hash::Hash for DiffTransformHunkInfo {
 660    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 661        self.excerpt_id.hash(state);
 662        self.hunk_start_anchor.hash(state);
 663    }
 664}
 665
 666#[derive(Clone)]
 667pub struct ExcerptInfo {
 668    pub id: ExcerptId,
 669    pub buffer: BufferSnapshot,
 670    pub buffer_id: BufferId,
 671    pub range: ExcerptRange<text::Anchor>,
 672    pub end_row: MultiBufferRow,
 673}
 674
 675impl std::fmt::Debug for ExcerptInfo {
 676    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 677        f.debug_struct(type_name::<Self>())
 678            .field("id", &self.id)
 679            .field("buffer_id", &self.buffer_id)
 680            .field("path", &self.buffer.file().map(|f| f.path()))
 681            .field("range", &self.range)
 682            .finish()
 683    }
 684}
 685
 686/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 687#[derive(Debug)]
 688pub struct ExcerptBoundary {
 689    pub prev: Option<ExcerptInfo>,
 690    pub next: ExcerptInfo,
 691    /// The row in the `MultiBuffer` where the boundary is located
 692    pub row: MultiBufferRow,
 693}
 694
 695impl ExcerptBoundary {
 696    pub fn starts_new_buffer(&self) -> bool {
 697        match (self.prev.as_ref(), &self.next) {
 698            (None, _) => true,
 699            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 700        }
 701    }
 702}
 703
 704#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 705pub struct ExpandInfo {
 706    pub direction: ExpandExcerptDirection,
 707    pub excerpt_id: ExcerptId,
 708}
 709
 710#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 711pub struct RowInfo {
 712    pub buffer_id: Option<BufferId>,
 713    pub buffer_row: Option<u32>,
 714    pub multibuffer_row: Option<MultiBufferRow>,
 715    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 716    pub expand_info: Option<ExpandInfo>,
 717    pub wrapped_buffer_row: Option<u32>,
 718}
 719
 720/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 721#[derive(Clone)]
 722struct Excerpt {
 723    /// The unique identifier for this excerpt
 724    id: ExcerptId,
 725    /// The location of the excerpt in the [`MultiBuffer`]
 726    locator: Locator,
 727    /// The buffer being excerpted
 728    buffer_id: BufferId,
 729    /// A snapshot of the buffer being excerpted
 730    buffer: BufferSnapshot,
 731    /// The range of the buffer to be shown in the excerpt
 732    range: ExcerptRange<text::Anchor>,
 733    /// The last row in the excerpted slice of the buffer
 734    max_buffer_row: BufferRow,
 735    /// A summary of the text in the excerpt
 736    text_summary: TextSummary,
 737    has_trailing_newline: bool,
 738}
 739
 740/// A public view into an `Excerpt` in a [`MultiBuffer`].
 741///
 742/// Contains methods for getting the [`Buffer`] of the excerpt,
 743/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 744#[derive(Clone)]
 745pub struct MultiBufferExcerpt<'a> {
 746    excerpt: &'a Excerpt,
 747    diff_transforms:
 748        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 749    /// The offset in the multibuffer considering diff transforms.
 750    offset: MultiBufferOffset,
 751    /// The offset in the multibuffer without diff transforms.
 752    excerpt_offset: ExcerptOffset,
 753    buffer_offset: BufferOffset,
 754}
 755
 756#[derive(Clone, Debug)]
 757struct ExcerptIdMapping {
 758    id: ExcerptId,
 759    locator: Locator,
 760}
 761
 762/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 763/// These ranges are relative to the buffer itself
 764#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 765pub struct ExcerptRange<T> {
 766    /// The full range of text to be shown in the excerpt.
 767    pub context: Range<T>,
 768    /// The primary range of text to be highlighted in the excerpt.
 769    /// In a multi-buffer search, this would be the text that matched the search
 770    pub primary: Range<T>,
 771}
 772
 773impl<T: Clone> ExcerptRange<T> {
 774    pub fn new(context: Range<T>) -> Self {
 775        Self {
 776            context: context.clone(),
 777            primary: context,
 778        }
 779    }
 780}
 781
 782#[derive(Clone, Debug, Default)]
 783pub struct ExcerptSummary {
 784    excerpt_id: ExcerptId,
 785    /// The location of the last [`Excerpt`] being summarized
 786    excerpt_locator: Locator,
 787    widest_line_number: u32,
 788    text: MBTextSummary,
 789}
 790
 791#[derive(Debug, Clone)]
 792pub struct DiffTransformSummary {
 793    input: MBTextSummary,
 794    output: MBTextSummary,
 795}
 796
 797/// Summary of a string of text.
 798#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 799pub struct MBTextSummary {
 800    /// Length in bytes.
 801    pub len: MultiBufferOffset,
 802    /// Length in UTF-8.
 803    pub chars: usize,
 804    /// Length in UTF-16 code units
 805    pub len_utf16: OffsetUtf16,
 806    /// A point representing the number of lines and the length of the last line.
 807    ///
 808    /// In other words, it marks the point after the last byte in the text, (if
 809    /// EOF was a character, this would be its position).
 810    pub lines: Point,
 811    /// How many `char`s are in the first line
 812    pub first_line_chars: u32,
 813    /// How many `char`s are in the last line
 814    pub last_line_chars: u32,
 815    /// How many UTF-16 code units are in the last line
 816    pub last_line_len_utf16: u32,
 817    /// The row idx of the longest row
 818    pub longest_row: u32,
 819    /// How many `char`s are in the longest row
 820    pub longest_row_chars: u32,
 821}
 822
 823impl From<TextSummary> for MBTextSummary {
 824    fn from(summary: TextSummary) -> Self {
 825        MBTextSummary {
 826            len: MultiBufferOffset(summary.len),
 827            chars: summary.chars,
 828            len_utf16: summary.len_utf16,
 829            lines: summary.lines,
 830            first_line_chars: summary.first_line_chars,
 831            last_line_chars: summary.last_line_chars,
 832            last_line_len_utf16: summary.last_line_len_utf16,
 833            longest_row: summary.longest_row,
 834            longest_row_chars: summary.longest_row_chars,
 835        }
 836    }
 837}
 838impl From<&str> for MBTextSummary {
 839    fn from(text: &str) -> Self {
 840        MBTextSummary::from(TextSummary::from(text))
 841    }
 842}
 843
 844impl MultiBufferDimension for MBTextSummary {
 845    type TextDimension = TextSummary;
 846
 847    fn from_summary(summary: &MBTextSummary) -> Self {
 848        *summary
 849    }
 850
 851    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 852        *self += *summary;
 853    }
 854
 855    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 856        *self += *summary;
 857    }
 858}
 859
 860impl AddAssign for MBTextSummary {
 861    fn add_assign(&mut self, other: MBTextSummary) {
 862        let joined_chars = self.last_line_chars + other.first_line_chars;
 863        if joined_chars > self.longest_row_chars {
 864            self.longest_row = self.lines.row;
 865            self.longest_row_chars = joined_chars;
 866        }
 867        if other.longest_row_chars > self.longest_row_chars {
 868            self.longest_row = self.lines.row + other.longest_row;
 869            self.longest_row_chars = other.longest_row_chars;
 870        }
 871
 872        if self.lines.row == 0 {
 873            self.first_line_chars += other.first_line_chars;
 874        }
 875
 876        if other.lines.row == 0 {
 877            self.last_line_chars += other.first_line_chars;
 878            self.last_line_len_utf16 += other.last_line_len_utf16;
 879        } else {
 880            self.last_line_chars = other.last_line_chars;
 881            self.last_line_len_utf16 = other.last_line_len_utf16;
 882        }
 883
 884        self.chars += other.chars;
 885        self.len += other.len;
 886        self.len_utf16 += other.len_utf16;
 887        self.lines += other.lines;
 888    }
 889}
 890
 891impl AddAssign<TextSummary> for MBTextSummary {
 892    fn add_assign(&mut self, other: TextSummary) {
 893        *self += MBTextSummary::from(other);
 894    }
 895}
 896
 897impl MBTextSummary {
 898    pub fn lines_utf16(&self) -> PointUtf16 {
 899        PointUtf16 {
 900            row: self.lines.row,
 901            column: self.last_line_len_utf16,
 902        }
 903    }
 904}
 905
 906impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 907where
 908    K: MultiBufferDimension,
 909    V: MultiBufferDimension,
 910{
 911    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 912
 913    fn from_summary(summary: &MBTextSummary) -> Self {
 914        Self {
 915            key: K::from_summary(summary),
 916            value: Some(V::from_summary(summary)),
 917        }
 918    }
 919
 920    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 921        self.key.add_text_dim(&summary.key);
 922        if let Some(value) = &mut self.value {
 923            if let Some(other_value) = summary.value.as_ref() {
 924                value.add_text_dim(other_value);
 925            }
 926        }
 927    }
 928
 929    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 930        self.key.add_mb_text_summary(summary);
 931        if let Some(value) = &mut self.value {
 932            value.add_mb_text_summary(summary);
 933        }
 934    }
 935}
 936
 937#[derive(Clone)]
 938pub struct MultiBufferRows<'a> {
 939    point: Point,
 940    is_empty: bool,
 941    is_singleton: bool,
 942    cursor: MultiBufferCursor<'a, Point, Point>,
 943}
 944
 945pub struct MultiBufferChunks<'a> {
 946    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 947    diff_transforms:
 948        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 949    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 950    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 951    buffer_chunk: Option<Chunk<'a>>,
 952    range: Range<MultiBufferOffset>,
 953    excerpt_offset_range: Range<ExcerptOffset>,
 954    excerpt_chunks: Option<ExcerptChunks<'a>>,
 955    language_aware: bool,
 956}
 957
 958pub struct ReversedMultiBufferChunks<'a> {
 959    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 960    current_chunks: Option<rope::Chunks<'a>>,
 961    start: MultiBufferOffset,
 962    offset: MultiBufferOffset,
 963}
 964
 965pub struct MultiBufferBytes<'a> {
 966    range: Range<MultiBufferOffset>,
 967    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 968    excerpt_bytes: Option<text::Bytes<'a>>,
 969    has_trailing_newline: bool,
 970    chunk: &'a [u8],
 971}
 972
 973pub struct ReversedMultiBufferBytes<'a> {
 974    range: Range<MultiBufferOffset>,
 975    chunks: ReversedMultiBufferChunks<'a>,
 976    chunk: &'a [u8],
 977}
 978
 979#[derive(Clone)]
 980struct DiffTransforms<MBD> {
 981    output_dimension: OutputDimension<MBD>,
 982    excerpt_dimension: ExcerptDimension<MBD>,
 983}
 984
 985impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
 986    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 987        Self {
 988            output_dimension: OutputDimension::zero(cx),
 989            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
 990                cx,
 991            ),
 992        }
 993    }
 994
 995    fn add_summary(
 996        &mut self,
 997        summary: &'a DiffTransformSummary,
 998        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 999    ) {
1000        self.output_dimension.add_summary(summary, cx);
1001        self.excerpt_dimension.add_summary(summary, cx);
1002    }
1003}
1004
1005#[derive(Clone)]
1006struct MultiBufferCursor<'a, MBD, BD> {
1007    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1008    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1009    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1010    cached_region: Option<MultiBufferRegion<'a, MBD, BD>>,
1011}
1012
1013#[derive(Clone)]
1014struct MultiBufferRegion<'a, MBD, BD> {
1015    buffer: &'a BufferSnapshot,
1016    is_main_buffer: bool,
1017    diff_hunk_status: Option<DiffHunkStatus>,
1018    excerpt: &'a Excerpt,
1019    buffer_range: Range<BD>,
1020    range: Range<MBD>,
1021    has_trailing_newline: bool,
1022}
1023
1024struct ExcerptChunks<'a> {
1025    excerpt_id: ExcerptId,
1026    content_chunks: BufferChunks<'a>,
1027    has_footer: bool,
1028}
1029
1030#[derive(Debug)]
1031struct BufferEdit {
1032    range: Range<BufferOffset>,
1033    new_text: Arc<str>,
1034    is_insertion: bool,
1035    original_indent_column: Option<u32>,
1036    excerpt_id: ExcerptId,
1037}
1038
1039#[derive(Clone, Copy, Debug, PartialEq)]
1040enum DiffChangeKind {
1041    BufferEdited,
1042    DiffUpdated { base_changed: bool },
1043    ExpandOrCollapseHunks { expand: bool },
1044}
1045
1046#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1047pub enum ExpandExcerptDirection {
1048    Up,
1049    Down,
1050    UpAndDown,
1051}
1052
1053impl ExpandExcerptDirection {
1054    pub fn should_expand_up(&self) -> bool {
1055        match self {
1056            ExpandExcerptDirection::Up => true,
1057            ExpandExcerptDirection::Down => false,
1058            ExpandExcerptDirection::UpAndDown => true,
1059        }
1060    }
1061
1062    pub fn should_expand_down(&self) -> bool {
1063        match self {
1064            ExpandExcerptDirection::Up => false,
1065            ExpandExcerptDirection::Down => true,
1066            ExpandExcerptDirection::UpAndDown => true,
1067        }
1068    }
1069}
1070
1071#[derive(Clone, Debug, PartialEq)]
1072pub struct IndentGuide {
1073    pub buffer_id: BufferId,
1074    pub start_row: MultiBufferRow,
1075    pub end_row: MultiBufferRow,
1076    pub depth: u32,
1077    pub tab_size: u32,
1078    pub settings: IndentGuideSettings,
1079}
1080
1081impl IndentGuide {
1082    pub fn indent_level(&self) -> u32 {
1083        self.depth * self.tab_size
1084    }
1085}
1086
1087impl MultiBuffer {
1088    pub fn new(capability: Capability) -> Self {
1089        Self::new_(
1090            capability,
1091            MultiBufferSnapshot {
1092                show_headers: true,
1093                show_deleted_hunks: true,
1094                ..MultiBufferSnapshot::default()
1095            },
1096        )
1097    }
1098
1099    pub fn without_headers(capability: Capability) -> Self {
1100        Self::new_(capability, Default::default())
1101    }
1102
1103    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1104        let mut this = Self::new_(
1105            buffer.read(cx).capability(),
1106            MultiBufferSnapshot {
1107                singleton: true,
1108                ..MultiBufferSnapshot::default()
1109            },
1110        );
1111        this.singleton = true;
1112        let buffer_id = buffer.read(cx).remote_id();
1113        this.push_excerpts(
1114            buffer,
1115            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1116                buffer_id,
1117            ))],
1118            cx,
1119        );
1120        this
1121    }
1122
1123    #[inline]
1124    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1125        Self {
1126            snapshot: RefCell::new(snapshot),
1127            buffers: Default::default(),
1128            diffs: HashMap::default(),
1129            subscriptions: Topic::default(),
1130            singleton: false,
1131            capability,
1132            title: None,
1133            excerpts_by_path: Default::default(),
1134            paths_by_excerpt: Default::default(),
1135            buffer_changed_since_sync: Default::default(),
1136            history: History::default(),
1137        }
1138    }
1139
1140    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1141        let mut buffers = HashMap::default();
1142        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1143        for (buffer_id, buffer_state) in self.buffers.iter() {
1144            buffer_state.buffer.update(new_cx, |buffer, _| {
1145                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1146            });
1147            buffers.insert(
1148                *buffer_id,
1149                BufferState {
1150                    buffer: buffer_state.buffer.clone(),
1151                    last_version: buffer_state.last_version.clone(),
1152                    last_non_text_state_update_count: buffer_state
1153                        .last_non_text_state_update_count
1154                        .clone(),
1155                    excerpts: buffer_state.excerpts.clone(),
1156                    _subscriptions: [
1157                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1158                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1159                    ],
1160                },
1161            );
1162        }
1163        let mut diff_bases = HashMap::default();
1164        for (buffer_id, diff) in self.diffs.iter() {
1165            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1166        }
1167        Self {
1168            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1169            buffers: buffers,
1170            excerpts_by_path: Default::default(),
1171            paths_by_excerpt: Default::default(),
1172            diffs: diff_bases,
1173            subscriptions: Default::default(),
1174            singleton: self.singleton,
1175            capability: self.capability,
1176            history: self.history.clone(),
1177            title: self.title.clone(),
1178            buffer_changed_since_sync,
1179        }
1180    }
1181
1182    pub fn set_group_interval(&mut self, group_interval: Duration) {
1183        self.history.set_group_interval(group_interval);
1184    }
1185
1186    pub fn with_title(mut self, title: String) -> Self {
1187        self.title = Some(title);
1188        self
1189    }
1190
1191    pub fn read_only(&self) -> bool {
1192        self.capability == Capability::ReadOnly
1193    }
1194
1195    /// Returns an up-to-date snapshot of the MultiBuffer.
1196    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1197        self.sync(cx);
1198        self.snapshot.borrow().clone()
1199    }
1200
1201    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1202        self.sync(cx);
1203        self.snapshot.borrow()
1204    }
1205
1206    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1207        if self.singleton {
1208            Some(self.buffers.values().next().unwrap().buffer.clone())
1209        } else {
1210            None
1211        }
1212    }
1213
1214    pub fn is_singleton(&self) -> bool {
1215        self.singleton
1216    }
1217
1218    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1219        self.subscriptions.subscribe()
1220    }
1221
1222    pub fn is_dirty(&self, cx: &App) -> bool {
1223        self.read(cx).is_dirty()
1224    }
1225
1226    pub fn has_deleted_file(&self, cx: &App) -> bool {
1227        self.read(cx).has_deleted_file()
1228    }
1229
1230    pub fn has_conflict(&self, cx: &App) -> bool {
1231        self.read(cx).has_conflict()
1232    }
1233
1234    // The `is_empty` signature doesn't match what clippy expects
1235    #[allow(clippy::len_without_is_empty)]
1236    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1237        self.read(cx).len()
1238    }
1239
1240    pub fn is_empty(&self) -> bool {
1241        self.buffers.is_empty()
1242    }
1243
1244    pub fn edit<I, S, T>(
1245        &mut self,
1246        edits: I,
1247        autoindent_mode: Option<AutoindentMode>,
1248        cx: &mut Context<Self>,
1249    ) where
1250        I: IntoIterator<Item = (Range<S>, T)>,
1251        S: ToOffset,
1252        T: Into<Arc<str>>,
1253    {
1254        if self.read_only() || self.buffers.is_empty() {
1255            return;
1256        }
1257        self.sync_mut(cx);
1258        let edits = edits
1259            .into_iter()
1260            .map(|(range, new_text)| {
1261                let mut range = range.start.to_offset(self.snapshot.get_mut())
1262                    ..range.end.to_offset(self.snapshot.get_mut());
1263                if range.start > range.end {
1264                    mem::swap(&mut range.start, &mut range.end);
1265                }
1266                (range, new_text.into())
1267            })
1268            .collect::<Vec<_>>();
1269
1270        return edit_internal(self, edits, autoindent_mode, cx);
1271
1272        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1273        fn edit_internal(
1274            this: &mut MultiBuffer,
1275            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1276            mut autoindent_mode: Option<AutoindentMode>,
1277            cx: &mut Context<MultiBuffer>,
1278        ) {
1279            let original_indent_columns = match &mut autoindent_mode {
1280                Some(AutoindentMode::Block {
1281                    original_indent_columns,
1282                }) => mem::take(original_indent_columns),
1283                _ => Default::default(),
1284            };
1285
1286            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1287                edits,
1288                this.snapshot.get_mut(),
1289                &original_indent_columns,
1290            );
1291
1292            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1293            for (buffer_id, mut edits) in buffer_edits {
1294                buffer_ids.push(buffer_id);
1295                edits.sort_by_key(|edit| edit.range.start);
1296                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1297                    let mut edits = edits.into_iter().peekable();
1298                    let mut insertions = Vec::new();
1299                    let mut original_indent_columns = Vec::new();
1300                    let mut deletions = Vec::new();
1301                    let empty_str: Arc<str> = Arc::default();
1302                    while let Some(BufferEdit {
1303                        mut range,
1304                        mut new_text,
1305                        mut is_insertion,
1306                        original_indent_column,
1307                        excerpt_id,
1308                    }) = edits.next()
1309                    {
1310                        while let Some(BufferEdit {
1311                            range: next_range,
1312                            is_insertion: next_is_insertion,
1313                            new_text: next_new_text,
1314                            excerpt_id: next_excerpt_id,
1315                            ..
1316                        }) = edits.peek()
1317                        {
1318                            if range.end >= next_range.start {
1319                                range.end = cmp::max(next_range.end, range.end);
1320                                is_insertion |= *next_is_insertion;
1321                                if excerpt_id == *next_excerpt_id {
1322                                    new_text = format!("{new_text}{next_new_text}").into();
1323                                }
1324                                edits.next();
1325                            } else {
1326                                break;
1327                            }
1328                        }
1329
1330                        if is_insertion {
1331                            original_indent_columns.push(original_indent_column);
1332                            insertions.push((
1333                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1334                                new_text.clone(),
1335                            ));
1336                        } else if !range.is_empty() {
1337                            deletions.push((
1338                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1339                                empty_str.clone(),
1340                            ));
1341                        }
1342                    }
1343
1344                    let deletion_autoindent_mode =
1345                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1346                            Some(AutoindentMode::Block {
1347                                original_indent_columns: Default::default(),
1348                            })
1349                        } else {
1350                            autoindent_mode.clone()
1351                        };
1352                    let insertion_autoindent_mode =
1353                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1354                            Some(AutoindentMode::Block {
1355                                original_indent_columns,
1356                            })
1357                        } else {
1358                            autoindent_mode.clone()
1359                        };
1360
1361                    buffer.edit(deletions, deletion_autoindent_mode, cx);
1362                    buffer.edit(insertions, insertion_autoindent_mode, cx);
1363                })
1364            }
1365
1366            cx.emit(Event::ExcerptsEdited {
1367                excerpt_ids: edited_excerpt_ids,
1368                buffer_ids,
1369            });
1370        }
1371    }
1372
1373    fn convert_edits_to_buffer_edits(
1374        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1375        snapshot: &MultiBufferSnapshot,
1376        original_indent_columns: &[Option<u32>],
1377    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1378        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1379        let mut edited_excerpt_ids = Vec::new();
1380        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1381        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1382            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1383
1384            cursor.seek(&range.start);
1385            let mut start_region = cursor.region().expect("start offset out of bounds");
1386            if !start_region.is_main_buffer {
1387                cursor.next();
1388                if let Some(region) = cursor.region() {
1389                    start_region = region;
1390                } else {
1391                    continue;
1392                }
1393            }
1394
1395            if range.end < start_region.range.start {
1396                continue;
1397            }
1398
1399            if range.end > start_region.range.end {
1400                cursor.seek_forward(&range.end);
1401            }
1402            let mut end_region = cursor.region().expect("end offset out of bounds");
1403            if !end_region.is_main_buffer {
1404                cursor.prev();
1405                if let Some(region) = cursor.region() {
1406                    end_region = region;
1407                } else {
1408                    continue;
1409                }
1410            }
1411
1412            if range.start > end_region.range.end {
1413                continue;
1414            }
1415
1416            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1417            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1418            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1419                .min(start_region.buffer_range.end);
1420            let buffer_end =
1421                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1422
1423            if start_region.excerpt.id == end_region.excerpt.id {
1424                if start_region.is_main_buffer {
1425                    edited_excerpt_ids.push(start_region.excerpt.id);
1426                    buffer_edits
1427                        .entry(start_region.buffer.remote_id())
1428                        .or_default()
1429                        .push(BufferEdit {
1430                            range: buffer_start..buffer_end,
1431                            new_text,
1432                            is_insertion: true,
1433                            original_indent_column,
1434                            excerpt_id: start_region.excerpt.id,
1435                        });
1436                }
1437            } else {
1438                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1439                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1440                if start_region.is_main_buffer {
1441                    edited_excerpt_ids.push(start_region.excerpt.id);
1442                    buffer_edits
1443                        .entry(start_region.buffer.remote_id())
1444                        .or_default()
1445                        .push(BufferEdit {
1446                            range: start_excerpt_range,
1447                            new_text: new_text.clone(),
1448                            is_insertion: true,
1449                            original_indent_column,
1450                            excerpt_id: start_region.excerpt.id,
1451                        });
1452                }
1453                if end_region.is_main_buffer {
1454                    edited_excerpt_ids.push(end_region.excerpt.id);
1455                    buffer_edits
1456                        .entry(end_region.buffer.remote_id())
1457                        .or_default()
1458                        .push(BufferEdit {
1459                            range: end_excerpt_range,
1460                            new_text: new_text.clone(),
1461                            is_insertion: false,
1462                            original_indent_column,
1463                            excerpt_id: end_region.excerpt.id,
1464                        });
1465                }
1466
1467                cursor.seek(&range.start);
1468                cursor.next_excerpt();
1469                while let Some(region) = cursor.region() {
1470                    if region.excerpt.id == end_region.excerpt.id {
1471                        break;
1472                    }
1473                    if region.is_main_buffer {
1474                        edited_excerpt_ids.push(region.excerpt.id);
1475                        buffer_edits
1476                            .entry(region.buffer.remote_id())
1477                            .or_default()
1478                            .push(BufferEdit {
1479                                range: region.buffer_range,
1480                                new_text: new_text.clone(),
1481                                is_insertion: false,
1482                                original_indent_column,
1483                                excerpt_id: region.excerpt.id,
1484                            });
1485                    }
1486                    cursor.next_excerpt();
1487                }
1488            }
1489        }
1490        (buffer_edits, edited_excerpt_ids)
1491    }
1492
1493    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1494    where
1495        I: IntoIterator<Item = Range<S>>,
1496        S: ToOffset,
1497    {
1498        if self.read_only() || self.buffers.is_empty() {
1499            return;
1500        }
1501        self.sync_mut(cx);
1502        let empty = Arc::<str>::from("");
1503        let edits = ranges
1504            .into_iter()
1505            .map(|range| {
1506                let mut range = range.start.to_offset(self.snapshot.get_mut())
1507                    ..range.end.to_offset(&self.snapshot.get_mut());
1508                if range.start > range.end {
1509                    mem::swap(&mut range.start, &mut range.end);
1510                }
1511                (range, empty.clone())
1512            })
1513            .collect::<Vec<_>>();
1514
1515        return autoindent_ranges_internal(self, edits, cx);
1516
1517        fn autoindent_ranges_internal(
1518            this: &mut MultiBuffer,
1519            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1520            cx: &mut Context<MultiBuffer>,
1521        ) {
1522            let (buffer_edits, edited_excerpt_ids) =
1523                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1524
1525            let mut buffer_ids = Vec::new();
1526            for (buffer_id, mut edits) in buffer_edits {
1527                buffer_ids.push(buffer_id);
1528                edits.sort_unstable_by_key(|edit| edit.range.start);
1529
1530                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1531                for edit in edits {
1532                    if let Some(last_range) = ranges.last_mut()
1533                        && edit.range.start <= last_range.end
1534                    {
1535                        last_range.end = last_range.end.max(edit.range.end);
1536                        continue;
1537                    }
1538                    ranges.push(edit.range);
1539                }
1540
1541                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1542                    buffer.autoindent_ranges(ranges, cx);
1543                })
1544            }
1545
1546            cx.emit(Event::ExcerptsEdited {
1547                excerpt_ids: edited_excerpt_ids,
1548                buffer_ids,
1549            });
1550        }
1551    }
1552
1553    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1554    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1555    /// Panics if the given position is invalid.
1556    pub fn insert_empty_line(
1557        &mut self,
1558        position: impl ToPoint,
1559        space_above: bool,
1560        space_below: bool,
1561        cx: &mut Context<Self>,
1562    ) -> Point {
1563        let multibuffer_point = position.to_point(&self.read(cx));
1564        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1565        self.start_transaction(cx);
1566        let empty_line_start = buffer.update(cx, |buffer, cx| {
1567            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1568        });
1569        self.end_transaction(cx);
1570        multibuffer_point + (empty_line_start - buffer_point)
1571    }
1572
1573    pub fn set_active_selections(
1574        &self,
1575        selections: &[Selection<Anchor>],
1576        line_mode: bool,
1577        cursor_shape: CursorShape,
1578        cx: &mut Context<Self>,
1579    ) {
1580        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1581            Default::default();
1582        let snapshot = self.read(cx);
1583        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1584        for selection in selections {
1585            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1586            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1587
1588            cursor.seek(&Some(start_locator), Bias::Left);
1589            while let Some(excerpt) = cursor.item()
1590                && excerpt.locator <= *end_locator
1591            {
1592                let mut start = excerpt.range.context.start;
1593                let mut end = excerpt.range.context.end;
1594                if excerpt.id == selection.start.excerpt_id {
1595                    start = selection.start.text_anchor;
1596                }
1597                if excerpt.id == selection.end.excerpt_id {
1598                    end = selection.end.text_anchor;
1599                }
1600                selections_by_buffer
1601                    .entry(excerpt.buffer_id)
1602                    .or_default()
1603                    .push(Selection {
1604                        id: selection.id,
1605                        start,
1606                        end,
1607                        reversed: selection.reversed,
1608                        goal: selection.goal,
1609                    });
1610
1611                cursor.next();
1612            }
1613        }
1614
1615        for (buffer_id, buffer_state) in self.buffers.iter() {
1616            if !selections_by_buffer.contains_key(buffer_id) {
1617                buffer_state
1618                    .buffer
1619                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1620            }
1621        }
1622
1623        for (buffer_id, mut selections) in selections_by_buffer {
1624            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1625                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1626                let mut selections = selections.into_iter().peekable();
1627                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1628                    let mut selection = selections.next()?;
1629                    while let Some(next_selection) = selections.peek() {
1630                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1631                            let next_selection = selections.next().unwrap();
1632                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1633                                selection.end = next_selection.end;
1634                            }
1635                        } else {
1636                            break;
1637                        }
1638                    }
1639                    Some(selection)
1640                }));
1641                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1642            });
1643        }
1644    }
1645
1646    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1647        for buffer in self.buffers.values() {
1648            buffer
1649                .buffer
1650                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1651        }
1652    }
1653
1654    pub fn push_excerpts<O>(
1655        &mut self,
1656        buffer: Entity<Buffer>,
1657        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1658        cx: &mut Context<Self>,
1659    ) -> Vec<ExcerptId>
1660    where
1661        O: text::ToOffset,
1662    {
1663        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1664    }
1665
1666    fn merge_excerpt_ranges<'a>(
1667        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1668    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1669        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1670        let mut counts: Vec<usize> = Vec::new();
1671        for range in expanded_ranges {
1672            if let Some(last_range) = merged_ranges.last_mut() {
1673                assert!(
1674                    last_range.context.start <= range.context.start,
1675                    "ranges must be sorted: {last_range:?} <= {range:?}"
1676                );
1677                if last_range.context.end >= range.context.start
1678                    || last_range.context.end.row + 1 == range.context.start.row
1679                {
1680                    last_range.context.end = range.context.end.max(last_range.context.end);
1681                    *counts.last_mut().unwrap() += 1;
1682                    continue;
1683                }
1684            }
1685            merged_ranges.push(range.clone());
1686            counts.push(1);
1687        }
1688        (merged_ranges, counts)
1689    }
1690
1691    pub fn insert_excerpts_after<O>(
1692        &mut self,
1693        prev_excerpt_id: ExcerptId,
1694        buffer: Entity<Buffer>,
1695        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1696        cx: &mut Context<Self>,
1697    ) -> Vec<ExcerptId>
1698    where
1699        O: text::ToOffset,
1700    {
1701        let mut ids = Vec::new();
1702        let mut next_excerpt_id =
1703            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1704                last_entry.id.0 + 1
1705            } else {
1706                1
1707            };
1708        self.insert_excerpts_with_ids_after(
1709            prev_excerpt_id,
1710            buffer,
1711            ranges.into_iter().map(|range| {
1712                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1713                ids.push(id);
1714                (id, range)
1715            }),
1716            cx,
1717        );
1718        ids
1719    }
1720
1721    pub fn insert_excerpts_with_ids_after<O>(
1722        &mut self,
1723        prev_excerpt_id: ExcerptId,
1724        buffer: Entity<Buffer>,
1725        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1726        cx: &mut Context<Self>,
1727    ) where
1728        O: text::ToOffset,
1729    {
1730        assert_eq!(self.history.transaction_depth(), 0);
1731        let mut ranges = ranges.into_iter().peekable();
1732        if ranges.peek().is_none() {
1733            return Default::default();
1734        }
1735
1736        self.sync_mut(cx);
1737
1738        let buffer_snapshot = buffer.read(cx).snapshot();
1739        let buffer_id = buffer_snapshot.remote_id();
1740
1741        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1742            self.buffer_changed_since_sync.replace(true);
1743            buffer.update(cx, |buffer, _| {
1744                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1745            });
1746            BufferState {
1747                last_version: RefCell::new(buffer_snapshot.version().clone()),
1748                last_non_text_state_update_count: Cell::new(
1749                    buffer_snapshot.non_text_state_update_count(),
1750                ),
1751                excerpts: Default::default(),
1752                _subscriptions: [
1753                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1754                    cx.subscribe(&buffer, Self::on_buffer_event),
1755                ],
1756                buffer: buffer.clone(),
1757            }
1758        });
1759
1760        let mut snapshot = self.snapshot.get_mut();
1761
1762        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1763        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1764        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1765        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1766        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1767
1768        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1769        new_excerpts.update_last(
1770            |excerpt| {
1771                excerpt.has_trailing_newline = true;
1772            },
1773            (),
1774        );
1775
1776        let next_locator = if let Some(excerpt) = cursor.item() {
1777            excerpt.locator.clone()
1778        } else {
1779            Locator::max()
1780        };
1781
1782        let mut excerpts = Vec::new();
1783        while let Some((id, range)) = ranges.next() {
1784            let locator = Locator::between(&prev_locator, &next_locator);
1785            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1786                buffer_state.excerpts.insert(ix, locator.clone());
1787            }
1788            let range = ExcerptRange {
1789                context: buffer_snapshot.anchor_before(&range.context.start)
1790                    ..buffer_snapshot.anchor_after(&range.context.end),
1791                primary: buffer_snapshot.anchor_before(&range.primary.start)
1792                    ..buffer_snapshot.anchor_after(&range.primary.end),
1793            };
1794            excerpts.push((id, range.clone()));
1795            let excerpt = Excerpt::new(
1796                id,
1797                locator.clone(),
1798                buffer_id,
1799                buffer_snapshot.clone(),
1800                range,
1801                ranges.peek().is_some() || cursor.item().is_some(),
1802            );
1803            new_excerpts.push(excerpt, ());
1804            prev_locator = locator.clone();
1805
1806            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1807                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1808            }
1809            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1810        }
1811
1812        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1813
1814        let suffix = cursor.suffix();
1815        let changed_trailing_excerpt = suffix.is_empty();
1816        new_excerpts.append(suffix, ());
1817        drop(cursor);
1818        snapshot.excerpts = new_excerpts;
1819        snapshot.excerpt_ids = new_excerpt_ids;
1820        if changed_trailing_excerpt {
1821            snapshot.trailing_excerpt_update_count += 1;
1822        }
1823
1824        let edits = Self::sync_diff_transforms(
1825            &mut snapshot,
1826            vec![Edit {
1827                old: edit_start..edit_start,
1828                new: edit_start..edit_end,
1829            }],
1830            DiffChangeKind::BufferEdited,
1831        );
1832        if !edits.is_empty() {
1833            self.subscriptions.publish(edits);
1834        }
1835
1836        cx.emit(Event::Edited {
1837            edited_buffer: None,
1838        });
1839        cx.emit(Event::ExcerptsAdded {
1840            buffer,
1841            predecessor: prev_excerpt_id,
1842            excerpts,
1843        });
1844        cx.notify();
1845    }
1846
1847    pub fn clear(&mut self, cx: &mut Context<Self>) {
1848        self.sync_mut(cx);
1849        let ids = self.excerpt_ids();
1850        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1851        self.excerpts_by_path.clear();
1852        self.paths_by_excerpt.clear();
1853        let MultiBufferSnapshot {
1854            excerpts,
1855            diffs: _,
1856            diff_transforms: _,
1857            non_text_state_update_count: _,
1858            edit_count: _,
1859            is_dirty,
1860            has_deleted_file,
1861            has_conflict,
1862            singleton: _,
1863            excerpt_ids: _,
1864            replaced_excerpts,
1865            trailing_excerpt_update_count,
1866            all_diff_hunks_expanded: _,
1867            show_deleted_hunks: _,
1868            show_headers: _,
1869        } = self.snapshot.get_mut();
1870        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1871        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1872        *excerpts = Default::default();
1873        *trailing_excerpt_update_count += 1;
1874        *is_dirty = false;
1875        *has_deleted_file = false;
1876        *has_conflict = false;
1877        replaced_excerpts.clear();
1878
1879        let edits = Self::sync_diff_transforms(
1880            self.snapshot.get_mut(),
1881            vec![Edit {
1882                old: start..prev_len,
1883                new: start..start,
1884            }],
1885            DiffChangeKind::BufferEdited,
1886        );
1887        if !edits.is_empty() {
1888            self.subscriptions.publish(edits);
1889        }
1890        cx.emit(Event::Edited {
1891            edited_buffer: None,
1892        });
1893        cx.emit(Event::ExcerptsRemoved {
1894            ids,
1895            removed_buffer_ids,
1896        });
1897        cx.notify();
1898    }
1899
1900    pub fn excerpts_for_buffer(
1901        &self,
1902        buffer_id: BufferId,
1903        cx: &App,
1904    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1905        let mut excerpts = Vec::new();
1906        let snapshot = self.read(cx);
1907        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1908        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1909            for locator in locators {
1910                cursor.seek_forward(&Some(locator), Bias::Left);
1911                if let Some(excerpt) = cursor.item()
1912                    && excerpt.locator == *locator
1913                {
1914                    excerpts.push((excerpt.id, excerpt.range.clone()));
1915                }
1916            }
1917        }
1918
1919        excerpts
1920    }
1921
1922    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1923        let snapshot = self.read(cx);
1924        let mut excerpts = snapshot
1925            .excerpts
1926            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
1927        let mut diff_transforms = snapshot
1928            .diff_transforms
1929            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1930        diff_transforms.next();
1931        let locators = self
1932            .buffers
1933            .get(&buffer_id)
1934            .into_iter()
1935            .flat_map(|state| &state.excerpts);
1936        let mut result = Vec::new();
1937        for locator in locators {
1938            excerpts.seek_forward(&Some(locator), Bias::Left);
1939            if let Some(excerpt) = excerpts.item()
1940                && excerpt.locator == *locator
1941            {
1942                let excerpt_start = excerpts.start().1;
1943                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1944
1945                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1946                let overshoot = excerpt_start - diff_transforms.start().0;
1947                let start = diff_transforms.start().1 + overshoot;
1948
1949                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1950                let overshoot = excerpt_end - diff_transforms.start().0;
1951                let end = diff_transforms.start().1 + overshoot;
1952
1953                result.push(start.0..end.0)
1954            }
1955        }
1956        result
1957    }
1958
1959    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1960        self.snapshot
1961            .borrow()
1962            .excerpts
1963            .iter()
1964            .map(|entry| entry.buffer_id)
1965            .collect()
1966    }
1967
1968    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1969        self.snapshot
1970            .borrow()
1971            .excerpts
1972            .iter()
1973            .map(|entry| entry.id)
1974            .collect()
1975    }
1976
1977    pub fn excerpt_containing(
1978        &self,
1979        position: impl ToOffset,
1980        cx: &App,
1981    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1982        let snapshot = self.read(cx);
1983        let offset = position.to_offset(&snapshot);
1984
1985        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1986        cursor.seek(&offset);
1987        cursor
1988            .excerpt()
1989            .or_else(|| snapshot.excerpts.last())
1990            .map(|excerpt| {
1991                (
1992                    excerpt.id,
1993                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1994                    excerpt.range.context.clone(),
1995                )
1996            })
1997    }
1998
1999    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2000        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2001            self.buffer(buffer_id)
2002        } else {
2003            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2004            Some(buffer)
2005        }
2006    }
2007
2008    // If point is at the end of the buffer, the last excerpt is returned
2009    pub fn point_to_buffer_offset<T: ToOffset>(
2010        &self,
2011        point: T,
2012        cx: &App,
2013    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2014        let snapshot = self.read(cx);
2015        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2016        Some((
2017            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2018            offset,
2019        ))
2020    }
2021
2022    // If point is at the end of the buffer, the last excerpt is returned
2023    pub fn point_to_buffer_point<T: ToPoint>(
2024        &self,
2025        point: T,
2026        cx: &App,
2027    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2028        let snapshot = self.read(cx);
2029        let (buffer, point, is_main_buffer) =
2030            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2031        Some((
2032            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2033            point,
2034            is_main_buffer,
2035        ))
2036    }
2037
2038    pub fn buffer_point_to_anchor(
2039        &self,
2040        buffer: &Entity<Buffer>,
2041        point: Point,
2042        cx: &App,
2043    ) -> Option<Anchor> {
2044        let mut found = None;
2045        let snapshot = buffer.read(cx).snapshot();
2046        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2047            let start = range.context.start.to_point(&snapshot);
2048            let end = range.context.end.to_point(&snapshot);
2049            if start <= point && point < end {
2050                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2051                break;
2052            }
2053            if point < start {
2054                found = Some((start, excerpt_id));
2055            }
2056            if point > end {
2057                found = Some((end, excerpt_id));
2058            }
2059        }
2060
2061        found.map(|(point, excerpt_id)| {
2062            let text_anchor = snapshot.anchor_after(point);
2063            Anchor::in_buffer(excerpt_id, text_anchor)
2064        })
2065    }
2066
2067    pub fn buffer_anchor_to_anchor(
2068        &self,
2069        buffer: &Entity<Buffer>,
2070        anchor: text::Anchor,
2071        cx: &App,
2072    ) -> Option<Anchor> {
2073        let snapshot = buffer.read(cx).snapshot();
2074        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2075            if range.context.start.cmp(&anchor, &snapshot).is_le()
2076                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2077            {
2078                return Some(Anchor::in_buffer(excerpt_id, anchor));
2079            }
2080        }
2081
2082        None
2083    }
2084
2085    pub fn remove_excerpts(
2086        &mut self,
2087        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2088        cx: &mut Context<Self>,
2089    ) {
2090        self.sync_mut(cx);
2091        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2092        if ids.is_empty() {
2093            return;
2094        }
2095        self.buffer_changed_since_sync.replace(true);
2096
2097        let mut snapshot = self.snapshot.get_mut();
2098        let mut new_excerpts = SumTree::default();
2099        let mut cursor = snapshot
2100            .excerpts
2101            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2102        let mut edits = Vec::new();
2103        let mut excerpt_ids = ids.iter().copied().peekable();
2104        let mut removed_buffer_ids = Vec::new();
2105
2106        while let Some(excerpt_id) = excerpt_ids.next() {
2107            self.paths_by_excerpt.remove(&excerpt_id);
2108            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2109            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2110            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2111
2112            if let Some(mut excerpt) = cursor.item() {
2113                if excerpt.id != excerpt_id {
2114                    continue;
2115                }
2116                let mut old_start = cursor.start().1;
2117
2118                // Skip over the removed excerpt.
2119                'remove_excerpts: loop {
2120                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2121                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2122                        if buffer_state.excerpts.is_empty() {
2123                            log::debug!(
2124                                "removing buffer and diff for buffer {}",
2125                                excerpt.buffer_id
2126                            );
2127                            self.buffers.remove(&excerpt.buffer_id);
2128                            removed_buffer_ids.push(excerpt.buffer_id);
2129                        }
2130                    }
2131                    cursor.next();
2132
2133                    // Skip over any subsequent excerpts that are also removed.
2134                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2135                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2136                        if let Some(next_excerpt) = cursor.item()
2137                            && next_excerpt.locator == *next_locator
2138                        {
2139                            excerpt_ids.next();
2140                            excerpt = next_excerpt;
2141                            continue 'remove_excerpts;
2142                        }
2143                    }
2144
2145                    break;
2146                }
2147
2148                // When removing the last excerpt, remove the trailing newline from
2149                // the previous excerpt.
2150                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2151                    old_start -= 1;
2152                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2153                }
2154
2155                // Push an edit for the removal of this run of excerpts.
2156                let old_end = cursor.start().1;
2157                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2158                edits.push(Edit {
2159                    old: old_start..old_end,
2160                    new: new_start..new_start,
2161                });
2162            }
2163        }
2164        let suffix = cursor.suffix();
2165        let changed_trailing_excerpt = suffix.is_empty();
2166        new_excerpts.append(suffix, ());
2167        drop(cursor);
2168        snapshot.excerpts = new_excerpts;
2169        for buffer_id in &removed_buffer_ids {
2170            self.diffs.remove(buffer_id);
2171            snapshot.diffs.remove(buffer_id);
2172        }
2173
2174        if changed_trailing_excerpt {
2175            snapshot.trailing_excerpt_update_count += 1;
2176        }
2177
2178        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2179        if !edits.is_empty() {
2180            self.subscriptions.publish(edits);
2181        }
2182        cx.emit(Event::Edited {
2183            edited_buffer: None,
2184        });
2185        cx.emit(Event::ExcerptsRemoved {
2186            ids,
2187            removed_buffer_ids,
2188        });
2189        cx.notify();
2190    }
2191
2192    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2193        &self,
2194        anchors: Anchors,
2195        cx: &mut Context<Self>,
2196    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2197        let mut error = None;
2198        let mut futures = Vec::new();
2199        for anchor in anchors {
2200            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2201                if let Some(buffer) = self.buffers.get(&buffer_id) {
2202                    buffer.buffer.update(cx, |buffer, _| {
2203                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2204                    });
2205                } else {
2206                    error = Some(anyhow!(
2207                        "buffer {buffer_id} is not part of this multi-buffer"
2208                    ));
2209                    break;
2210                }
2211            }
2212        }
2213        async move {
2214            if let Some(error) = error {
2215                Err(error)?;
2216            }
2217            for future in futures {
2218                future.await?;
2219            }
2220            Ok(())
2221        }
2222    }
2223
2224    pub fn text_anchor_for_position<T: ToOffset>(
2225        &self,
2226        position: T,
2227        cx: &App,
2228    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2229        let snapshot = self.read(cx);
2230        let anchor = snapshot.anchor_before(position);
2231        let buffer = self
2232            .buffers
2233            .get(&anchor.text_anchor.buffer_id?)?
2234            .buffer
2235            .clone();
2236        Some((buffer, anchor.text_anchor))
2237    }
2238
2239    fn on_buffer_event(
2240        &mut self,
2241        buffer: Entity<Buffer>,
2242        event: &language::BufferEvent,
2243        cx: &mut Context<Self>,
2244    ) {
2245        use language::BufferEvent;
2246        cx.emit(match event {
2247            BufferEvent::Edited => Event::Edited {
2248                edited_buffer: Some(buffer),
2249            },
2250            BufferEvent::DirtyChanged => Event::DirtyChanged,
2251            BufferEvent::Saved => Event::Saved,
2252            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2253            BufferEvent::Reloaded => Event::Reloaded,
2254            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2255            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2256            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2257            BufferEvent::CapabilityChanged => {
2258                self.capability = buffer.read(cx).capability();
2259                return;
2260            }
2261            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2262        });
2263    }
2264
2265    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2266        let diff = diff.read(cx);
2267        let buffer_id = diff.buffer_id;
2268        let diff = DiffStateSnapshot {
2269            diff: diff.snapshot(cx),
2270            is_inverted: false,
2271        };
2272        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2273    }
2274
2275    fn inverted_buffer_diff_language_changed(
2276        &mut self,
2277        base_text_buffer_id: BufferId,
2278        diff: Entity<BufferDiff>,
2279        cx: &mut Context<Self>,
2280    ) {
2281        let diff = diff.read(cx);
2282        let diff = DiffStateSnapshot {
2283            diff: diff.snapshot(cx),
2284            is_inverted: true,
2285        };
2286        self.snapshot
2287            .get_mut()
2288            .diffs
2289            .insert(base_text_buffer_id, diff);
2290    }
2291
2292    fn buffer_diff_changed(
2293        &mut self,
2294        diff: Entity<BufferDiff>,
2295        range: Range<text::Anchor>,
2296        cx: &mut Context<Self>,
2297    ) {
2298        self.sync_mut(cx);
2299
2300        let diff = diff.read(cx);
2301        let buffer_id = diff.buffer_id;
2302        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2303            return;
2304        };
2305        self.buffer_changed_since_sync.replace(true);
2306
2307        let buffer = buffer_state.buffer.read(cx);
2308        let diff_change_range = range.to_offset(buffer);
2309
2310        let new_diff = DiffStateSnapshot {
2311            diff: diff.snapshot(cx),
2312            is_inverted: false,
2313        };
2314        let mut snapshot = self.snapshot.get_mut();
2315        let base_text_changed = snapshot
2316            .diffs
2317            .get(&buffer_id)
2318            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2319
2320        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2321
2322        let mut excerpt_edits = Vec::new();
2323        for locator in &buffer_state.excerpts {
2324            let mut cursor = snapshot
2325                .excerpts
2326                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2327            cursor.seek_forward(&Some(locator), Bias::Left);
2328            if let Some(excerpt) = cursor.item()
2329                && excerpt.locator == *locator
2330            {
2331                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2332                if diff_change_range.end < excerpt_buffer_range.start
2333                    || diff_change_range.start > excerpt_buffer_range.end
2334                {
2335                    continue;
2336                }
2337                let excerpt_start = cursor.start().1;
2338                let excerpt_len = excerpt.text_summary.len;
2339                let diff_change_start_in_excerpt = diff_change_range
2340                    .start
2341                    .saturating_sub(excerpt_buffer_range.start);
2342                let diff_change_end_in_excerpt = diff_change_range
2343                    .end
2344                    .saturating_sub(excerpt_buffer_range.start);
2345                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2346                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2347                excerpt_edits.push(Edit {
2348                    old: edit_start..edit_end,
2349                    new: edit_start..edit_end,
2350                });
2351            }
2352        }
2353
2354        let edits = Self::sync_diff_transforms(
2355            &mut snapshot,
2356            excerpt_edits,
2357            DiffChangeKind::DiffUpdated {
2358                base_changed: base_text_changed,
2359            },
2360        );
2361        if !edits.is_empty() {
2362            self.subscriptions.publish(edits);
2363        }
2364        cx.emit(Event::Edited {
2365            edited_buffer: None,
2366        });
2367    }
2368
2369    fn inverted_buffer_diff_changed(
2370        &mut self,
2371        diff: Entity<BufferDiff>,
2372        diff_change_range: Range<usize>,
2373        base_text_buffer_id: BufferId,
2374        cx: &mut Context<Self>,
2375    ) {
2376        // FIXME move this to the level of the splittableeditor
2377        // if base_text_changed && let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) {
2378        //     buffer_state.buffer.update(cx, |buffer, cx| {
2379        //         // FIXME use the rope directly
2380        //         buffer.set_text(diff.read(cx).base_text().text(), cx);
2381        //     });
2382        // }
2383        self.sync_mut(cx);
2384
2385        let diff = diff.read(cx);
2386        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2387            return;
2388        };
2389        self.buffer_changed_since_sync.replace(true);
2390
2391        let new_diff = DiffStateSnapshot {
2392            diff: diff.snapshot(cx),
2393            is_inverted: true,
2394        };
2395        let mut snapshot = self.snapshot.get_mut();
2396        let base_text_changed = snapshot
2397            .diffs
2398            .get(&base_text_buffer_id)
2399            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2400
2401        snapshot
2402            .diffs
2403            .insert_or_replace(base_text_buffer_id, new_diff);
2404
2405        let mut excerpt_edits = Vec::new();
2406        for locator in &buffer_state.excerpts {
2407            let mut cursor = snapshot
2408                .excerpts
2409                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2410            cursor.seek_forward(&Some(locator), Bias::Left);
2411            if let Some(excerpt) = cursor.item()
2412                && excerpt.locator == *locator
2413            {
2414                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2415                if diff_change_range.end < excerpt_buffer_range.start
2416                    || diff_change_range.start > excerpt_buffer_range.end
2417                {
2418                    continue;
2419                }
2420                let excerpt_start = cursor.start().1;
2421                let excerpt_len = excerpt.text_summary.len;
2422                let diff_change_start_in_excerpt = diff_change_range
2423                    .start
2424                    .saturating_sub(excerpt_buffer_range.start);
2425                let diff_change_end_in_excerpt = diff_change_range
2426                    .end
2427                    .saturating_sub(excerpt_buffer_range.start);
2428                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2429                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2430                excerpt_edits.push(Edit {
2431                    old: edit_start..edit_end,
2432                    new: edit_start..edit_end,
2433                });
2434            }
2435        }
2436
2437        let edits = Self::sync_diff_transforms(
2438            &mut snapshot,
2439            excerpt_edits,
2440            DiffChangeKind::DiffUpdated {
2441                base_changed: base_text_changed,
2442            },
2443        );
2444        if !edits.is_empty() {
2445            self.subscriptions.publish(edits);
2446        }
2447        cx.emit(Event::Edited {
2448            edited_buffer: None,
2449        });
2450    }
2451
2452    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2453        self.buffers.values().map(|state| state.buffer.clone())
2454    }
2455
2456    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2457        self.all_buffers_iter().collect()
2458    }
2459
2460    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2461        self.buffers.keys().copied()
2462    }
2463
2464    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2465        self.all_buffer_ids_iter().collect()
2466    }
2467
2468    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2469        self.buffers
2470            .get(&buffer_id)
2471            .map(|state| state.buffer.clone())
2472    }
2473
2474    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2475        self.point_to_buffer_offset(point, cx)
2476            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2477    }
2478
2479    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2480        let buffer_id = self
2481            .snapshot
2482            .borrow()
2483            .excerpts
2484            .first()
2485            .map(|excerpt| excerpt.buffer.remote_id());
2486        buffer_id
2487            .and_then(|buffer_id| self.buffer(buffer_id))
2488            .map(|buffer| {
2489                let buffer = buffer.read(cx);
2490                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2491            })
2492            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2493    }
2494
2495    pub fn language_settings_at<'a, T: ToOffset>(
2496        &'a self,
2497        point: T,
2498        cx: &'a App,
2499    ) -> Cow<'a, LanguageSettings> {
2500        let mut language = None;
2501        let mut file = None;
2502        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2503            let buffer = buffer.read(cx);
2504            language = buffer.language_at(offset);
2505            file = buffer.file();
2506        }
2507        language_settings(language.map(|l| l.name()), file, cx)
2508    }
2509
2510    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2511        self.buffers.values().for_each(|state| f(&state.buffer))
2512    }
2513
2514    pub fn explicit_title(&self) -> Option<&str> {
2515        self.title.as_deref()
2516    }
2517
2518    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2519        if let Some(title) = self.title.as_ref() {
2520            return title.into();
2521        }
2522
2523        if let Some(buffer) = self.as_singleton() {
2524            let buffer = buffer.read(cx);
2525
2526            if let Some(file) = buffer.file() {
2527                return file.file_name(cx).into();
2528            }
2529
2530            if let Some(title) = self.buffer_content_title(buffer) {
2531                return title;
2532            }
2533        };
2534
2535        "untitled".into()
2536    }
2537
2538    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2539        let mut is_leading_whitespace = true;
2540        let mut count = 0;
2541        let mut prev_was_space = false;
2542        let mut title = String::new();
2543
2544        for ch in buffer.snapshot().chars() {
2545            if is_leading_whitespace && ch.is_whitespace() {
2546                continue;
2547            }
2548
2549            is_leading_whitespace = false;
2550
2551            if ch == '\n' || count >= 40 {
2552                break;
2553            }
2554
2555            if ch.is_whitespace() {
2556                if !prev_was_space {
2557                    title.push(' ');
2558                    count += 1;
2559                    prev_was_space = true;
2560                }
2561            } else {
2562                title.push(ch);
2563                count += 1;
2564                prev_was_space = false;
2565            }
2566        }
2567
2568        let title = title.trim_end().to_string();
2569
2570        if title.is_empty() {
2571            return None;
2572        }
2573
2574        Some(title.into())
2575    }
2576
2577    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2578        self.title = Some(title);
2579        cx.notify();
2580    }
2581
2582    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2583    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2584        for buffer_state in self.buffers.values() {
2585            buffer_state
2586                .buffer
2587                .update(cx, |buffer, _cx| buffer.refresh_preview());
2588        }
2589    }
2590
2591    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2592    pub fn preserve_preview(&self, cx: &App) -> bool {
2593        self.buffers
2594            .values()
2595            .all(|state| state.buffer.read(cx).preserve_preview())
2596    }
2597
2598    #[cfg(any(test, feature = "test-support"))]
2599    pub fn is_parsing(&self, cx: &App) -> bool {
2600        self.as_singleton().unwrap().read(cx).is_parsing()
2601    }
2602
2603    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2604        debug_assert!(self.diffs.values().all(|diff| !diff.is_inverted));
2605
2606        let buffer_id = diff.read(cx).buffer_id;
2607        self.buffer_diff_changed(
2608            diff.clone(),
2609            text::Anchor::min_max_range_for_buffer(buffer_id),
2610            cx,
2611        );
2612        self.diffs
2613            .insert(buffer_id, DiffState::new(diff.clone(), cx));
2614    }
2615
2616    pub fn add_inverted_diff(
2617        &mut self,
2618        base_text_buffer_id: BufferId,
2619        diff: Entity<BufferDiff>,
2620        cx: &mut Context<Self>,
2621    ) {
2622        debug_assert!(self.diffs.values().all(|diff| diff.is_inverted));
2623
2624        let diff_change_range = 0..diff.read(cx).base_text().len();
2625        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, base_text_buffer_id, cx);
2626        self.diffs.insert(
2627            base_text_buffer_id,
2628            DiffState::new_inverted(diff, base_text_buffer_id, cx),
2629        );
2630    }
2631
2632    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2633        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2634    }
2635
2636    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2637        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2638    }
2639
2640    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2641        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2642    }
2643
2644    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2645        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2646        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2647    }
2648
2649    pub fn all_diff_hunks_expanded(&self) -> bool {
2650        self.snapshot.borrow().all_diff_hunks_expanded
2651    }
2652
2653    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2654        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2655        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2656    }
2657
2658    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2659        self.snapshot.get_mut().show_deleted_hunks = show;
2660        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2661    }
2662
2663    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2664        self.read(cx)
2665            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2666            .nth(1)
2667            .is_some()
2668    }
2669
2670    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2671        let snapshot = self.read(cx);
2672        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2673        let offset_range = range.to_offset(&snapshot);
2674        cursor.seek(&offset_range.start, Bias::Left);
2675        while let Some(item) = cursor.item() {
2676            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2677                break;
2678            }
2679            if item.hunk_info().is_some() {
2680                return true;
2681            }
2682            cursor.next();
2683        }
2684        false
2685    }
2686
2687    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2688        let snapshot = self.read(cx);
2689        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2690        for range in ranges {
2691            let range = range.to_point(&snapshot);
2692            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2693            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2694            let start = start.saturating_sub_usize(1);
2695            let end = snapshot.len().min(end + 1usize);
2696            cursor.seek(&start, Bias::Right);
2697            while let Some(item) = cursor.item() {
2698                if *cursor.start() >= end {
2699                    break;
2700                }
2701                if item.hunk_info().is_some() {
2702                    return true;
2703                }
2704                cursor.next();
2705            }
2706        }
2707        false
2708    }
2709
2710    pub fn expand_or_collapse_diff_hunks_inner(
2711        &mut self,
2712        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2713        expand: bool,
2714        cx: &mut Context<Self>,
2715    ) {
2716        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2717            return;
2718        }
2719        self.sync_mut(cx);
2720        let mut snapshot = self.snapshot.get_mut();
2721        let mut excerpt_edits = Vec::new();
2722        let mut last_hunk_row = None;
2723        for (range, end_excerpt_id) in ranges {
2724            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2725                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2726                    continue;
2727                }
2728                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2729                    continue;
2730                }
2731                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2732                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2733                let start = snapshot.excerpt_offset_for_anchor(&start);
2734                let end = snapshot.excerpt_offset_for_anchor(&end);
2735                last_hunk_row = Some(diff_hunk.row_range.start);
2736                excerpt_edits.push(text::Edit {
2737                    old: start..end,
2738                    new: start..end,
2739                });
2740            }
2741        }
2742
2743        let edits = Self::sync_diff_transforms(
2744            &mut snapshot,
2745            excerpt_edits,
2746            DiffChangeKind::ExpandOrCollapseHunks { expand },
2747        );
2748        if !edits.is_empty() {
2749            self.subscriptions.publish(edits);
2750        }
2751        cx.emit(Event::DiffHunksToggled);
2752        cx.emit(Event::Edited {
2753            edited_buffer: None,
2754        });
2755    }
2756
2757    pub fn expand_or_collapse_diff_hunks(
2758        &mut self,
2759        ranges: Vec<Range<Anchor>>,
2760        expand: bool,
2761        cx: &mut Context<Self>,
2762    ) {
2763        let snapshot = self.snapshot.borrow().clone();
2764        let ranges = ranges.iter().map(move |range| {
2765            let end_excerpt_id = range.end.excerpt_id;
2766            let range = range.to_point(&snapshot);
2767            let mut peek_end = range.end;
2768            if range.end.row < snapshot.max_row().0 {
2769                peek_end = Point::new(range.end.row + 1, 0);
2770            };
2771            (range.start..peek_end, end_excerpt_id)
2772        });
2773        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2774    }
2775
2776    pub fn resize_excerpt(
2777        &mut self,
2778        id: ExcerptId,
2779        range: Range<text::Anchor>,
2780        cx: &mut Context<Self>,
2781    ) {
2782        self.sync_mut(cx);
2783
2784        let mut snapshot = self.snapshot.get_mut();
2785        let locator = snapshot.excerpt_locator_for_id(id);
2786        let mut new_excerpts = SumTree::default();
2787        let mut cursor = snapshot
2788            .excerpts
2789            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2790        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2791
2792        let prefix = cursor.slice(&Some(locator), Bias::Left);
2793        new_excerpts.append(prefix, ());
2794
2795        let mut excerpt = cursor.item().unwrap().clone();
2796        let old_text_len = excerpt.text_summary.len;
2797
2798        excerpt.range.context.start = range.start;
2799        excerpt.range.context.end = range.end;
2800        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2801
2802        excerpt.text_summary = excerpt
2803            .buffer
2804            .text_summary_for_range(excerpt.range.context.clone());
2805
2806        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2807        let old_start_offset = cursor.start().1;
2808        let new_text_len = excerpt.text_summary.len;
2809        let edit = Edit {
2810            old: old_start_offset..old_start_offset + old_text_len,
2811            new: new_start_offset..new_start_offset + new_text_len,
2812        };
2813
2814        if let Some(last_edit) = edits.last_mut() {
2815            if last_edit.old.end == edit.old.start {
2816                last_edit.old.end = edit.old.end;
2817                last_edit.new.end = edit.new.end;
2818            } else {
2819                edits.push(edit);
2820            }
2821        } else {
2822            edits.push(edit);
2823        }
2824
2825        new_excerpts.push(excerpt, ());
2826
2827        cursor.next();
2828
2829        new_excerpts.append(cursor.suffix(), ());
2830
2831        drop(cursor);
2832        snapshot.excerpts = new_excerpts;
2833
2834        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2835        if !edits.is_empty() {
2836            self.subscriptions.publish(edits);
2837        }
2838        cx.emit(Event::Edited {
2839            edited_buffer: None,
2840        });
2841        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2842        cx.notify();
2843    }
2844
2845    pub fn expand_excerpts(
2846        &mut self,
2847        ids: impl IntoIterator<Item = ExcerptId>,
2848        line_count: u32,
2849        direction: ExpandExcerptDirection,
2850        cx: &mut Context<Self>,
2851    ) {
2852        if line_count == 0 {
2853            return;
2854        }
2855        self.sync_mut(cx);
2856        if !self.excerpts_by_path.is_empty() {
2857            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2858            return;
2859        }
2860        let mut snapshot = self.snapshot.get_mut();
2861
2862        let ids = ids.into_iter().collect::<Vec<_>>();
2863        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2864        let mut new_excerpts = SumTree::default();
2865        let mut cursor = snapshot
2866            .excerpts
2867            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2868        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2869
2870        for locator in &locators {
2871            let prefix = cursor.slice(&Some(locator), Bias::Left);
2872            new_excerpts.append(prefix, ());
2873
2874            let mut excerpt = cursor.item().unwrap().clone();
2875            let old_text_len = excerpt.text_summary.len;
2876
2877            let up_line_count = if direction.should_expand_up() {
2878                line_count
2879            } else {
2880                0
2881            };
2882
2883            let start_row = excerpt
2884                .range
2885                .context
2886                .start
2887                .to_point(&excerpt.buffer)
2888                .row
2889                .saturating_sub(up_line_count);
2890            let start_point = Point::new(start_row, 0);
2891            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2892
2893            let down_line_count = if direction.should_expand_down() {
2894                line_count
2895            } else {
2896                0
2897            };
2898
2899            let mut end_point = excerpt.buffer.clip_point(
2900                excerpt.range.context.end.to_point(&excerpt.buffer)
2901                    + Point::new(down_line_count, 0),
2902                Bias::Left,
2903            );
2904            end_point.column = excerpt.buffer.line_len(end_point.row);
2905            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2906            excerpt.max_buffer_row = end_point.row;
2907
2908            excerpt.text_summary = excerpt
2909                .buffer
2910                .text_summary_for_range(excerpt.range.context.clone());
2911
2912            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2913            let old_start_offset = cursor.start().1;
2914            let new_text_len = excerpt.text_summary.len;
2915            let edit = Edit {
2916                old: old_start_offset..old_start_offset + old_text_len,
2917                new: new_start_offset..new_start_offset + new_text_len,
2918            };
2919
2920            if let Some(last_edit) = edits.last_mut() {
2921                if last_edit.old.end == edit.old.start {
2922                    last_edit.old.end = edit.old.end;
2923                    last_edit.new.end = edit.new.end;
2924                } else {
2925                    edits.push(edit);
2926                }
2927            } else {
2928                edits.push(edit);
2929            }
2930
2931            new_excerpts.push(excerpt, ());
2932
2933            cursor.next();
2934        }
2935
2936        new_excerpts.append(cursor.suffix(), ());
2937
2938        drop(cursor);
2939        snapshot.excerpts = new_excerpts;
2940
2941        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2942        if !edits.is_empty() {
2943            self.subscriptions.publish(edits);
2944        }
2945        cx.emit(Event::Edited {
2946            edited_buffer: None,
2947        });
2948        cx.emit(Event::ExcerptsExpanded { ids });
2949        cx.notify();
2950    }
2951
2952    fn sync(&self, cx: &App) {
2953        let changed = self.buffer_changed_since_sync.replace(false);
2954        if !changed {
2955            return;
2956        }
2957        let edits = Self::sync_(
2958            &mut self.snapshot.borrow_mut(),
2959            &self.buffers,
2960            &self.diffs,
2961            cx,
2962        );
2963        if !edits.is_empty() {
2964            self.subscriptions.publish(edits);
2965        }
2966    }
2967
2968    fn sync_mut(&mut self, cx: &App) {
2969        let changed = self.buffer_changed_since_sync.replace(false);
2970        if !changed {
2971            return;
2972        }
2973        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2974
2975        if !edits.is_empty() {
2976            self.subscriptions.publish(edits);
2977        }
2978    }
2979
2980    fn sync_(
2981        snapshot: &mut MultiBufferSnapshot,
2982        buffers: &HashMap<BufferId, BufferState>,
2983        diffs: &HashMap<BufferId, DiffState>,
2984        cx: &App,
2985    ) -> Vec<Edit<MultiBufferOffset>> {
2986        let MultiBufferSnapshot {
2987            excerpts,
2988            diffs: buffer_diff,
2989            diff_transforms: _,
2990            non_text_state_update_count,
2991            edit_count,
2992            is_dirty,
2993            has_deleted_file,
2994            has_conflict,
2995            singleton: _,
2996            excerpt_ids: _,
2997            replaced_excerpts: _,
2998            trailing_excerpt_update_count: _,
2999            all_diff_hunks_expanded: _,
3000            show_deleted_hunks: _,
3001            show_headers: _,
3002        } = snapshot;
3003        *is_dirty = false;
3004        *has_deleted_file = false;
3005        *has_conflict = false;
3006
3007        let mut excerpts_to_edit = Vec::new();
3008        let mut non_text_state_updated = false;
3009        let mut edited = false;
3010        for buffer_state in buffers.values() {
3011            let buffer = buffer_state.buffer.read(cx);
3012            let version = buffer.version();
3013            let non_text_state_update_count = buffer.non_text_state_update_count();
3014
3015            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3016            let buffer_non_text_state_updated =
3017                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3018            if buffer_edited || buffer_non_text_state_updated {
3019                *buffer_state.last_version.borrow_mut() = version;
3020                buffer_state
3021                    .last_non_text_state_update_count
3022                    .set(non_text_state_update_count);
3023                excerpts_to_edit.extend(
3024                    buffer_state
3025                        .excerpts
3026                        .iter()
3027                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3028                );
3029            }
3030
3031            edited |= buffer_edited;
3032            non_text_state_updated |= buffer_non_text_state_updated;
3033            *is_dirty |= buffer.is_dirty();
3034            *has_deleted_file |= buffer
3035                .file()
3036                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3037            *has_conflict |= buffer.has_conflict();
3038        }
3039        if edited {
3040            *edit_count += 1;
3041        }
3042        if non_text_state_updated {
3043            *non_text_state_update_count += 1;
3044        }
3045
3046        for (id, diff) in diffs.iter() {
3047            if buffer_diff.get(id).is_none() {
3048                buffer_diff.insert(*id, diff.snapshot(cx));
3049            }
3050        }
3051
3052        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3053
3054        let mut edits = Vec::new();
3055        let mut new_excerpts = SumTree::default();
3056        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3057
3058        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3059            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3060            let old_excerpt = cursor.item().unwrap();
3061            let buffer = buffer.read(cx);
3062            let buffer_id = buffer.remote_id();
3063
3064            let mut new_excerpt;
3065            if buffer_edited {
3066                edits.extend(
3067                    buffer
3068                        .edits_since_in_range::<usize>(
3069                            old_excerpt.buffer.version(),
3070                            old_excerpt.range.context.clone(),
3071                        )
3072                        .map(|edit| {
3073                            let excerpt_old_start = cursor.start().1;
3074                            let excerpt_new_start =
3075                                ExcerptDimension(new_excerpts.summary().text.len);
3076                            let old_start = excerpt_old_start + edit.old.start;
3077                            let old_end = excerpt_old_start + edit.old.end;
3078                            let new_start = excerpt_new_start + edit.new.start;
3079                            let new_end = excerpt_new_start + edit.new.end;
3080                            Edit {
3081                                old: old_start..old_end,
3082                                new: new_start..new_end,
3083                            }
3084                        }),
3085                );
3086
3087                new_excerpt = Excerpt::new(
3088                    old_excerpt.id,
3089                    locator.clone(),
3090                    buffer_id,
3091                    buffer.snapshot(),
3092                    old_excerpt.range.clone(),
3093                    old_excerpt.has_trailing_newline,
3094                );
3095            } else {
3096                new_excerpt = old_excerpt.clone();
3097                new_excerpt.buffer = buffer.snapshot();
3098            }
3099
3100            new_excerpts.push(new_excerpt, ());
3101            cursor.next();
3102        }
3103        new_excerpts.append(cursor.suffix(), ());
3104
3105        drop(cursor);
3106        *excerpts = new_excerpts;
3107        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3108    }
3109
3110    fn sync_diff_transforms(
3111        snapshot: &mut MultiBufferSnapshot,
3112        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3113        change_kind: DiffChangeKind,
3114    ) -> Vec<Edit<MultiBufferOffset>> {
3115        if excerpt_edits.is_empty() {
3116            return vec![];
3117        }
3118
3119        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3120        let mut old_diff_transforms = snapshot
3121            .diff_transforms
3122            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3123        let mut new_diff_transforms = SumTree::default();
3124        let mut old_expanded_hunks = HashSet::default();
3125        let mut output_edits = Vec::new();
3126        let mut output_delta = 0_isize;
3127        let mut at_transform_boundary = true;
3128        let mut end_of_current_insert = None;
3129
3130        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3131        while let Some(edit) = excerpt_edits.next() {
3132            excerpts.seek_forward(&edit.new.start, Bias::Right);
3133            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3134                excerpts.prev();
3135            }
3136
3137            // Keep any transforms that are before the edit.
3138            if at_transform_boundary {
3139                at_transform_boundary = false;
3140                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3141                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3142                if let Some(transform) = old_diff_transforms.item()
3143                    && old_diff_transforms.end().0 == edit.old.start
3144                    && old_diff_transforms.start().0 < edit.old.start
3145                {
3146                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3147                    old_diff_transforms.next();
3148                }
3149            }
3150
3151            // Compute the start of the edit in output coordinates.
3152            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3153            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3154            let edit_new_start =
3155                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3156
3157            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3158                &edit,
3159                &mut excerpts,
3160                &mut old_diff_transforms,
3161                &mut new_diff_transforms,
3162                &mut end_of_current_insert,
3163                &mut old_expanded_hunks,
3164                snapshot,
3165                change_kind,
3166            );
3167
3168            // Compute the end of the edit in output coordinates.
3169            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3170            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3171            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3172            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3173            let output_edit = Edit {
3174                old: edit_old_start..edit_old_end,
3175                new: edit_new_start..edit_new_end,
3176            };
3177
3178            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3179            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3180            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3181                output_edits.push(output_edit);
3182            }
3183
3184            // If this is the last edit that intersects the current diff transform,
3185            // then recreate the content up to the end of this transform, to prepare
3186            // for reusing additional slices of the old transforms.
3187            if excerpt_edits
3188                .peek()
3189                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3190            {
3191                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3192                    && match old_diff_transforms.item() {
3193                        Some(DiffTransform::BufferContent {
3194                            inserted_hunk_info: Some(hunk),
3195                            ..
3196                        }) => excerpts.item().is_some_and(|excerpt| {
3197                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3198                        }),
3199                        _ => true,
3200                    };
3201
3202                let mut excerpt_offset = edit.new.end;
3203                if !keep_next_old_transform {
3204                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3205                    old_diff_transforms.next();
3206                }
3207
3208                old_expanded_hunks.clear();
3209                Self::push_buffer_content_transform(
3210                    snapshot,
3211                    &mut new_diff_transforms,
3212                    excerpt_offset,
3213                    end_of_current_insert,
3214                );
3215                at_transform_boundary = true;
3216            }
3217        }
3218
3219        // Keep any transforms that are after the last edit.
3220        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3221
3222        // Ensure there's always at least one buffer content transform.
3223        if new_diff_transforms.is_empty() {
3224            new_diff_transforms.push(
3225                DiffTransform::BufferContent {
3226                    summary: Default::default(),
3227                    inserted_hunk_info: None,
3228                },
3229                (),
3230            );
3231        }
3232
3233        drop(old_diff_transforms);
3234        drop(excerpts);
3235        snapshot.diff_transforms = new_diff_transforms;
3236        snapshot.edit_count += 1;
3237
3238        #[cfg(any(test, feature = "test-support"))]
3239        snapshot.check_invariants();
3240        output_edits
3241    }
3242
3243    fn recompute_diff_transforms_for_edit(
3244        edit: &Edit<ExcerptOffset>,
3245        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3246        old_diff_transforms: &mut Cursor<
3247            DiffTransform,
3248            Dimensions<ExcerptOffset, MultiBufferOffset>,
3249        >,
3250        new_diff_transforms: &mut SumTree<DiffTransform>,
3251        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3252        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3253        snapshot: &MultiBufferSnapshot,
3254        change_kind: DiffChangeKind,
3255    ) -> bool {
3256        log::trace!(
3257            "recomputing diff transform for edit {:?} => {:?}",
3258            edit.old.start..edit.old.end,
3259            edit.new.start..edit.new.end
3260        );
3261
3262        // Record which hunks were previously expanded.
3263        while let Some(item) = old_diff_transforms.item() {
3264            if let Some(hunk_info) = item.hunk_info() {
3265                log::trace!(
3266                    "previously expanded hunk at {:?}",
3267                    old_diff_transforms.start()
3268                );
3269                old_expanded_hunks.insert(hunk_info);
3270            }
3271            if old_diff_transforms.end().0 > edit.old.end {
3272                break;
3273            }
3274            old_diff_transforms.next();
3275        }
3276
3277        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3278        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3279        if old_expanded_hunks.is_empty()
3280            && change_kind == DiffChangeKind::BufferEdited
3281            && !all_diff_hunks_expanded
3282        {
3283            return false;
3284        }
3285
3286        // Visit each excerpt that intersects the edit.
3287        let mut did_expand_hunks = false;
3288        while let Some(excerpt) = excerpts.item() {
3289            // Recompute the expanded hunks in the portion of the excerpt that
3290            // intersects the edit.
3291            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3292                let buffer = &excerpt.buffer;
3293                let excerpt_start = *excerpts.start();
3294                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3295                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3296                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3297                let edit_buffer_start =
3298                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3299                let edit_buffer_end =
3300                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3301                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3302
3303                if diff.is_inverted {
3304                    for hunk in
3305                        diff.hunks_intersecting_base_text_range(edit_buffer_start..edit_buffer_end)
3306                    {
3307                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3308                        if hunk_buffer_range.start < excerpt_buffer_start {
3309                            log::trace!("skipping hunk that starts before excerpt");
3310                            continue;
3311                        }
3312                        let hunk_excerpt_start = excerpt_start
3313                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3314                        let hunk_excerpt_end = excerpt_end
3315                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3316                        Self::push_buffer_content_transform(
3317                            snapshot,
3318                            new_diff_transforms,
3319                            hunk_excerpt_start,
3320                            *end_of_current_insert,
3321                        );
3322                        // FIXME record that the status for this region should be "deleted"
3323                        if !hunk_buffer_range.is_empty() {
3324                            let hunk_info = DiffTransformHunkInfo {
3325                                excerpt_id: excerpt.id,
3326                                hunk_start_anchor: hunk.buffer_range.start,
3327                                hunk_secondary_status: hunk.secondary_status,
3328                            };
3329                            *end_of_current_insert =
3330                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3331                        }
3332                    }
3333                    continue;
3334                }
3335
3336                let edit_anchor_range =
3337                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3338                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3339                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3340                        continue;
3341                    }
3342
3343                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3344                    if hunk_buffer_range.start < excerpt_buffer_start {
3345                        log::trace!("skipping hunk that starts before excerpt");
3346                        continue;
3347                    }
3348
3349                    let hunk_info = DiffTransformHunkInfo {
3350                        excerpt_id: excerpt.id,
3351                        hunk_start_anchor: hunk.buffer_range.start,
3352                        hunk_secondary_status: hunk.secondary_status,
3353                    };
3354
3355                    let hunk_excerpt_start = excerpt_start
3356                        + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3357                    let hunk_excerpt_end = excerpt_end
3358                        .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3359
3360                    Self::push_buffer_content_transform(
3361                        snapshot,
3362                        new_diff_transforms,
3363                        hunk_excerpt_start,
3364                        *end_of_current_insert,
3365                    );
3366
3367                    // For every existing hunk, determine if it was previously expanded
3368                    // and if it should currently be expanded.
3369                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3370                    let should_expand_hunk = match &change_kind {
3371                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3372                            was_previously_expanded || all_diff_hunks_expanded
3373                        }
3374                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3375                            let intersects = hunk_buffer_range.is_empty()
3376                                || hunk_buffer_range.end > edit_buffer_start;
3377                            if *expand {
3378                                intersects || was_previously_expanded || all_diff_hunks_expanded
3379                            } else {
3380                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3381                            }
3382                        }
3383                        _ => was_previously_expanded || all_diff_hunks_expanded,
3384                    };
3385
3386                    if should_expand_hunk {
3387                        did_expand_hunks = true;
3388                        log::trace!(
3389                            "expanding hunk {:?}, excerpt:{:?}",
3390                            hunk_excerpt_start..hunk_excerpt_end,
3391                            excerpt.id
3392                        );
3393
3394                        if !hunk.diff_base_byte_range.is_empty()
3395                            && hunk_buffer_range.start >= edit_buffer_start
3396                            && hunk_buffer_range.start <= excerpt_buffer_end
3397                            && snapshot.show_deleted_hunks
3398                        {
3399                            let base_text = diff.base_text();
3400                            let mut text_cursor =
3401                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3402                            let mut base_text_summary =
3403                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3404
3405                            let mut has_trailing_newline = false;
3406                            if base_text_summary.last_line_chars > 0 {
3407                                base_text_summary += TextSummary::newline();
3408                                has_trailing_newline = true;
3409                            }
3410
3411                            new_diff_transforms.push(
3412                                DiffTransform::DeletedHunk {
3413                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3414                                    summary: base_text_summary,
3415                                    buffer_id: excerpt.buffer_id,
3416                                    hunk_info,
3417                                    has_trailing_newline,
3418                                },
3419                                (),
3420                            );
3421                        }
3422
3423                        if !hunk_buffer_range.is_empty() {
3424                            *end_of_current_insert =
3425                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3426                        }
3427                    }
3428                }
3429            }
3430
3431            if excerpts.end() <= edit.new.end {
3432                excerpts.next();
3433            } else {
3434                break;
3435            }
3436        }
3437
3438        did_expand_hunks || !old_expanded_hunks.is_empty()
3439    }
3440
3441    fn append_diff_transforms(
3442        new_transforms: &mut SumTree<DiffTransform>,
3443        subtree: SumTree<DiffTransform>,
3444    ) {
3445        if let Some(DiffTransform::BufferContent {
3446            inserted_hunk_info,
3447            summary,
3448        }) = subtree.first()
3449            && Self::extend_last_buffer_content_transform(
3450                new_transforms,
3451                *inserted_hunk_info,
3452                *summary,
3453            )
3454        {
3455            let mut cursor = subtree.cursor::<()>(());
3456            cursor.next();
3457            cursor.next();
3458            new_transforms.append(cursor.suffix(), ());
3459            return;
3460        }
3461        new_transforms.append(subtree, ());
3462    }
3463
3464    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3465        if let DiffTransform::BufferContent {
3466            inserted_hunk_info: inserted_hunk_anchor,
3467            summary,
3468        } = transform
3469            && Self::extend_last_buffer_content_transform(
3470                new_transforms,
3471                inserted_hunk_anchor,
3472                summary,
3473            )
3474        {
3475            return;
3476        }
3477        new_transforms.push(transform, ());
3478    }
3479
3480    fn push_buffer_content_transform(
3481        old_snapshot: &MultiBufferSnapshot,
3482        new_transforms: &mut SumTree<DiffTransform>,
3483        end_offset: ExcerptOffset,
3484        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3485    ) {
3486        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3487            (end_offset.min(insertion_end_offset), Some(hunk_info))
3488        });
3489        let unchanged_region = [(end_offset, None)];
3490
3491        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3492        {
3493            let start_offset = new_transforms.summary().excerpt_len();
3494            if end_offset <= start_offset {
3495                continue;
3496            }
3497            let summary_to_add = old_snapshot
3498                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3499
3500            if !Self::extend_last_buffer_content_transform(
3501                new_transforms,
3502                inserted_hunk_info,
3503                summary_to_add,
3504            ) {
3505                new_transforms.push(
3506                    DiffTransform::BufferContent {
3507                        summary: summary_to_add,
3508                        inserted_hunk_info,
3509                    },
3510                    (),
3511                )
3512            }
3513        }
3514    }
3515
3516    fn extend_last_buffer_content_transform(
3517        new_transforms: &mut SumTree<DiffTransform>,
3518        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3519        summary_to_add: MBTextSummary,
3520    ) -> bool {
3521        let mut did_extend = false;
3522        new_transforms.update_last(
3523            |last_transform| {
3524                if let DiffTransform::BufferContent {
3525                    summary,
3526                    inserted_hunk_info: inserted_hunk_anchor,
3527                } = last_transform
3528                    && *inserted_hunk_anchor == new_inserted_hunk_info
3529                {
3530                    *summary += summary_to_add;
3531                    did_extend = true;
3532                }
3533            },
3534            (),
3535        );
3536        did_extend
3537    }
3538}
3539
3540fn build_excerpt_ranges(
3541    ranges: impl IntoIterator<Item = Range<Point>>,
3542    context_line_count: u32,
3543    buffer_snapshot: &BufferSnapshot,
3544) -> Vec<ExcerptRange<Point>> {
3545    ranges
3546        .into_iter()
3547        .map(|range| {
3548            let start_row = range.start.row.saturating_sub(context_line_count);
3549            let start = Point::new(start_row, 0);
3550            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3551            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3552            ExcerptRange {
3553                context: start..end,
3554                primary: range,
3555            }
3556        })
3557        .collect()
3558}
3559
3560#[cfg(any(test, feature = "test-support"))]
3561impl MultiBuffer {
3562    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3563        let buffer = cx.new(|cx| Buffer::local(text, cx));
3564        cx.new(|cx| Self::singleton(buffer, cx))
3565    }
3566
3567    pub fn build_multi<const COUNT: usize>(
3568        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3569        cx: &mut gpui::App,
3570    ) -> Entity<Self> {
3571        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3572        for (text, ranges) in excerpts {
3573            let buffer = cx.new(|cx| Buffer::local(text, cx));
3574            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3575            multi.update(cx, |multi, cx| {
3576                multi.push_excerpts(buffer, excerpt_ranges, cx)
3577            });
3578        }
3579
3580        multi
3581    }
3582
3583    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3584        cx.new(|cx| Self::singleton(buffer, cx))
3585    }
3586
3587    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3588        cx.new(|cx| {
3589            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3590            let mutation_count = rng.random_range(1..=5);
3591            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3592            multibuffer
3593        })
3594    }
3595
3596    pub fn randomly_edit(
3597        &mut self,
3598        rng: &mut impl rand::Rng,
3599        edit_count: usize,
3600        cx: &mut Context<Self>,
3601    ) {
3602        use util::RandomCharIter;
3603
3604        let snapshot = self.read(cx);
3605        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3606        let mut last_end = None;
3607        for _ in 0..edit_count {
3608            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3609                break;
3610            }
3611
3612            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3613            let end =
3614                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3615            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3616            last_end = Some(end);
3617
3618            let mut range = start..end;
3619            if rng.random_bool(0.2) {
3620                mem::swap(&mut range.start, &mut range.end);
3621            }
3622
3623            let new_text_len = rng.random_range(0..10);
3624            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3625
3626            edits.push((range, new_text.into()));
3627        }
3628        log::info!("mutating multi-buffer with {:?}", edits);
3629        drop(snapshot);
3630
3631        self.edit(edits, None, cx);
3632    }
3633
3634    pub fn randomly_edit_excerpts(
3635        &mut self,
3636        rng: &mut impl rand::Rng,
3637        mutation_count: usize,
3638        cx: &mut Context<Self>,
3639    ) {
3640        use rand::prelude::*;
3641        use std::env;
3642        use util::RandomCharIter;
3643
3644        let max_excerpts = env::var("MAX_EXCERPTS")
3645            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3646            .unwrap_or(5);
3647
3648        let mut buffers = Vec::new();
3649        for _ in 0..mutation_count {
3650            if rng.random_bool(0.05) {
3651                log::info!("Clearing multi-buffer");
3652                self.clear(cx);
3653                continue;
3654            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3655                let ids = self.excerpt_ids();
3656                let mut excerpts = HashSet::default();
3657                for _ in 0..rng.random_range(0..ids.len()) {
3658                    excerpts.extend(ids.choose(rng).copied());
3659                }
3660
3661                let line_count = rng.random_range(0..5);
3662
3663                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3664
3665                self.expand_excerpts(
3666                    excerpts.iter().cloned(),
3667                    line_count,
3668                    ExpandExcerptDirection::UpAndDown,
3669                    cx,
3670                );
3671                continue;
3672            }
3673
3674            let excerpt_ids = self.excerpt_ids();
3675            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3676                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3677                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3678                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3679                    let buffer = buffers.last().unwrap().read(cx);
3680                    log::info!(
3681                        "Creating new buffer {} with text: {:?}",
3682                        buffer.remote_id(),
3683                        buffer.text()
3684                    );
3685                    buffers.last().unwrap().clone()
3686                } else {
3687                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3688                };
3689
3690                let buffer = buffer_handle.read(cx);
3691                let buffer_text = buffer.text();
3692                let ranges = (0..rng.random_range(0..5))
3693                    .map(|_| {
3694                        let end_ix =
3695                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3696                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3697                        ExcerptRange::new(start_ix..end_ix)
3698                    })
3699                    .collect::<Vec<_>>();
3700                log::info!(
3701                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3702                    buffer_handle.read(cx).remote_id(),
3703                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3704                    ranges
3705                        .iter()
3706                        .map(|r| &buffer_text[r.context.clone()])
3707                        .collect::<Vec<_>>()
3708                );
3709
3710                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3711                log::info!("Inserted with ids: {:?}", excerpt_id);
3712            } else {
3713                let remove_count = rng.random_range(1..=excerpt_ids.len());
3714                let mut excerpts_to_remove = excerpt_ids
3715                    .choose_multiple(rng, remove_count)
3716                    .cloned()
3717                    .collect::<Vec<_>>();
3718                let snapshot = self.snapshot.borrow();
3719                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3720                drop(snapshot);
3721                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3722                self.remove_excerpts(excerpts_to_remove, cx);
3723            }
3724        }
3725    }
3726
3727    pub fn randomly_mutate(
3728        &mut self,
3729        rng: &mut impl rand::Rng,
3730        mutation_count: usize,
3731        cx: &mut Context<Self>,
3732    ) {
3733        use rand::prelude::*;
3734
3735        if rng.random_bool(0.7) || self.singleton {
3736            let buffer = self
3737                .buffers
3738                .values()
3739                .choose(rng)
3740                .map(|state| state.buffer.clone());
3741
3742            if let Some(buffer) = buffer {
3743                buffer.update(cx, |buffer, cx| {
3744                    if rng.random() {
3745                        buffer.randomly_edit(rng, mutation_count, cx);
3746                    } else {
3747                        buffer.randomly_undo_redo(rng, cx);
3748                    }
3749                });
3750            } else {
3751                self.randomly_edit(rng, mutation_count, cx);
3752            }
3753        } else {
3754            self.randomly_edit_excerpts(rng, mutation_count, cx);
3755        }
3756
3757        self.check_invariants(cx);
3758    }
3759
3760    fn check_invariants(&self, cx: &App) {
3761        self.read(cx).check_invariants();
3762    }
3763}
3764
3765impl EventEmitter<Event> for MultiBuffer {}
3766
3767impl MultiBufferSnapshot {
3768    pub fn text(&self) -> String {
3769        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3770            .map(|chunk| chunk.text)
3771            .collect()
3772    }
3773
3774    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3775        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3776            .flat_map(|c| c.chars().rev())
3777    }
3778
3779    fn reversed_chunks_in_range(
3780        &self,
3781        range: Range<MultiBufferOffset>,
3782    ) -> ReversedMultiBufferChunks<'_> {
3783        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3784        cursor.seek(&range.end);
3785        let current_chunks = cursor.region().as_ref().map(|region| {
3786            let start_overshoot = range.start.saturating_sub(region.range.start);
3787            let end_overshoot = range.end - region.range.start;
3788            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3789            let start = region.buffer_range.start + start_overshoot;
3790            region.buffer.reversed_chunks_in_range(start..end)
3791        });
3792        ReversedMultiBufferChunks {
3793            cursor,
3794            current_chunks,
3795            start: range.start,
3796            offset: range.end,
3797        }
3798    }
3799
3800    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3801        let offset = position.to_offset(self);
3802        self.text_for_range(offset..self.len())
3803            .flat_map(|chunk| chunk.chars())
3804    }
3805
3806    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3807        self.chunks(range, false).map(|chunk| chunk.text)
3808    }
3809
3810    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3811        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3812            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3813    }
3814
3815    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3816    where
3817        T: ToOffset,
3818    {
3819        let position = position.to_offset(self);
3820        position == self.clip_offset(position, Bias::Left)
3821            && self
3822                .bytes_in_range(position..self.len())
3823                .flatten()
3824                .copied()
3825                .take(needle.len())
3826                .eq(needle.bytes())
3827    }
3828
3829    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3830        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3831    }
3832
3833    pub fn diff_hunks_in_range<T: ToPoint>(
3834        &self,
3835        range: Range<T>,
3836    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3837        let query_range = range.start.to_point(self)..range.end.to_point(self);
3838        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3839            let diff = self.diffs.get(&buffer.remote_id())?;
3840            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3841                if diff.is_inverted {
3842                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3843                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3844                    Box::new(
3845                        diff.hunks_intersecting_base_text_range(buffer_start..buffer_end)
3846                            .map(move |hunk| (hunk, buffer, true)),
3847                    )
3848                } else {
3849                    let buffer_start = buffer.anchor_before(buffer_range.start);
3850                    let buffer_end = buffer.anchor_after(buffer_range.end);
3851                    Box::new(
3852                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3853                            .map(move |hunk| (hunk, buffer, false)),
3854                    )
3855                };
3856            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3857                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3858                    return None;
3859                }
3860                let range = if is_inverted {
3861                    hunk.diff_base_byte_range.to_point(&buffer)
3862                } else {
3863                    hunk.range.clone()
3864                };
3865                Some((range, (hunk, is_inverted)))
3866            }))
3867        })
3868        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3869            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3870            {
3871                return None;
3872            }
3873            let end_row = if range.end.column == 0 {
3874                range.end.row
3875            } else {
3876                range.end.row + 1
3877            };
3878
3879            let word_diffs = (!hunk.base_word_diffs.is_empty()
3880                || !hunk.buffer_word_diffs.is_empty())
3881            .then(|| {
3882                let hunk_start_offset =
3883                    Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_offset(self);
3884
3885                hunk.base_word_diffs
3886                    .iter()
3887                    .map(|diff| hunk_start_offset + diff.start..hunk_start_offset + diff.end)
3888                    .chain(
3889                        hunk.buffer_word_diffs
3890                            .into_iter()
3891                            .map(|diff| Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)),
3892                    )
3893                    .collect()
3894            })
3895            .unwrap_or_default();
3896
3897            let buffer_range = if is_inverted {
3898                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3899                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3900            } else {
3901                hunk.buffer_range.clone()
3902            };
3903            Some(MultiBufferDiffHunk {
3904                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3905                buffer_id: excerpt.buffer_id,
3906                excerpt_id: excerpt.id,
3907                buffer_range,
3908                word_diffs,
3909                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3910                    ..BufferOffset(hunk.diff_base_byte_range.end),
3911                secondary_status: hunk.secondary_status,
3912            })
3913        })
3914    }
3915
3916    fn excerpts_for_range<T: ToOffset>(
3917        &self,
3918        range: Range<T>,
3919    ) -> impl Iterator<Item = &Excerpt> + '_ {
3920        let range = range.start.to_offset(self)..range.end.to_offset(self);
3921        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3922        cursor.seek(&range.start);
3923        std::iter::from_fn(move || {
3924            let region = cursor.region()?;
3925            if region.range.start > range.end
3926                || region.range.start == range.end && region.range.start > range.start
3927            {
3928                return None;
3929            }
3930            cursor.next_excerpt();
3931            Some(region.excerpt)
3932        })
3933    }
3934
3935    pub fn excerpt_ids_for_range<T: ToOffset>(
3936        &self,
3937        range: Range<T>,
3938    ) -> impl Iterator<Item = ExcerptId> + '_ {
3939        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3940    }
3941
3942    pub fn buffer_ids_for_range<T: ToOffset>(
3943        &self,
3944        range: Range<T>,
3945    ) -> impl Iterator<Item = BufferId> + '_ {
3946        self.excerpts_for_range(range)
3947            .map(|excerpt| excerpt.buffer_id)
3948    }
3949
3950    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3951        &self,
3952        ranges: impl Iterator<Item = Range<T>>,
3953    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3954        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3955    }
3956
3957    pub fn range_to_buffer_ranges<T: ToOffset>(
3958        &self,
3959        range: Range<T>,
3960    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3961        let start = range.start.to_offset(self);
3962        let end = range.end.to_offset(self);
3963
3964        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3965        cursor.seek(&start);
3966
3967        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
3968        while let Some(region) = cursor.region() {
3969            if region.range.start > end {
3970                break;
3971            }
3972            if region.is_main_buffer {
3973                let start_overshoot = start.saturating_sub(region.range.start);
3974                let end_overshoot = end.saturating_sub(region.range.start);
3975                let start = region
3976                    .buffer_range
3977                    .end
3978                    .min(region.buffer_range.start + start_overshoot);
3979                let end = region
3980                    .buffer_range
3981                    .end
3982                    .min(region.buffer_range.start + end_overshoot);
3983                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3984                    *excerpt_id == region.excerpt.id && prev_range.end == start
3985                }) {
3986                    prev.1.end = end;
3987                } else {
3988                    result.push((region.buffer, start..end, region.excerpt.id));
3989                }
3990            }
3991            cursor.next();
3992        }
3993        result
3994    }
3995
3996    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3997        &self,
3998        range: Range<T>,
3999    ) -> impl Iterator<
4000        Item = (
4001            &BufferSnapshot,
4002            Range<BufferOffset>,
4003            ExcerptId,
4004            Option<Anchor>,
4005        ),
4006    > + '_ {
4007        let start = range.start.to_offset(self);
4008        let end = range.end.to_offset(self);
4009
4010        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4011        cursor.seek(&start);
4012
4013        std::iter::from_fn(move || {
4014            let region = cursor.region()?;
4015            if region.range.start > end {
4016                return None;
4017            }
4018            let start_overshoot = start.saturating_sub(region.range.start);
4019            let end_overshoot = end.saturating_sub(region.range.start);
4020            let start = region
4021                .buffer_range
4022                .end
4023                .min(region.buffer_range.start + start_overshoot);
4024            let end = region
4025                .buffer_range
4026                .end
4027                .min(region.buffer_range.start + end_overshoot);
4028
4029            let region_excerpt_id = region.excerpt.id;
4030            let deleted_hunk_anchor = if region.is_main_buffer {
4031                None
4032            } else {
4033                Some(self.anchor_before(region.range.start))
4034            };
4035            let result = (
4036                region.buffer,
4037                start..end,
4038                region_excerpt_id,
4039                deleted_hunk_anchor,
4040            );
4041            cursor.next();
4042            Some(result)
4043        })
4044    }
4045
4046    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4047    /// coordinates.
4048    ///
4049    /// The given callback will be called for every excerpt intersecting the given range. It will
4050    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4051    /// The callback should return an iterator of metadata items from that buffer, each paired
4052    /// with a buffer range.
4053    ///
4054    /// The returned iterator yields each of these metadata items, paired with its range in
4055    /// multi-buffer coordinates.
4056    fn lift_buffer_metadata<'a, MBD, M, I>(
4057        &'a self,
4058        query_range: Range<MBD>,
4059        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4060    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4061    where
4062        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4063        MBD: MultiBufferDimension
4064            + Ord
4065            + Sub<Output = MBD::TextDimension>
4066            + ops::Add<MBD::TextDimension, Output = MBD>
4067            + ops::AddAssign<MBD::TextDimension>,
4068        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4069            + ops::Add<Output = MBD::TextDimension>
4070            + AddAssign<MBD::TextDimension>
4071            + Ord,
4072    {
4073        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4074        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4075
4076        // Find the excerpt and buffer offset where the given range ends.
4077        cursor.seek(&query_range.end);
4078        let mut range_end = None;
4079        while let Some(region) = cursor.region() {
4080            if region.is_main_buffer {
4081                let mut buffer_end = region.buffer_range.start;
4082                let overshoot = if query_range.end > region.range.start {
4083                    query_range.end - region.range.start
4084                } else {
4085                    <MBD::TextDimension>::default()
4086                };
4087                buffer_end = buffer_end + overshoot;
4088                range_end = Some((region.excerpt.id, buffer_end));
4089                break;
4090            }
4091            cursor.next();
4092        }
4093
4094        cursor.seek(&query_range.start);
4095
4096        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4097            && region.range.start > MBD::default()
4098        {
4099            cursor.prev()
4100        }
4101
4102        iter::from_fn(move || {
4103            loop {
4104                let excerpt = cursor.excerpt()?;
4105
4106                // If we have already retrieved metadata for this excerpt, continue to use it.
4107                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4108                    .as_mut()
4109                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4110                {
4111                    Some(metadata)
4112                }
4113                // Otherwise, compute the intersection of the input range with the excerpt's range,
4114                // and retrieve the metadata for the resulting range.
4115                else {
4116                    let region = cursor.region()?;
4117                    let mut buffer_start;
4118                    if region.is_main_buffer {
4119                        buffer_start = region.buffer_range.start;
4120                        if query_range.start > region.range.start {
4121                            let overshoot = query_range.start - region.range.start;
4122                            buffer_start = buffer_start + overshoot;
4123                        }
4124                        buffer_start = buffer_start.min(region.buffer_range.end);
4125                    } else {
4126                        buffer_start = cursor.main_buffer_position()?;
4127                    };
4128                    let mut buffer_end = excerpt
4129                        .range
4130                        .context
4131                        .end
4132                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4133                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4134                        && excerpt.id == end_excerpt_id
4135                    {
4136                        buffer_end = buffer_end.min(end_buffer_offset);
4137                    }
4138
4139                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4140                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4141                    })
4142                };
4143
4144                // Visit each metadata item.
4145                if let Some((metadata_buffer_range, metadata)) =
4146                    metadata_iter.and_then(Iterator::next)
4147                {
4148                    // Find the multibuffer regions that contain the start and end of
4149                    // the metadata item's range.
4150                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4151                        while let Some(region) = cursor.region() {
4152                            if region.is_main_buffer
4153                                && (region.buffer_range.end >= metadata_buffer_range.start
4154                                    || cursor.is_at_end_of_excerpt())
4155                            {
4156                                break;
4157                            }
4158                            cursor.next();
4159                        }
4160                    }
4161                    let start_region = cursor.region()?;
4162                    while let Some(region) = cursor.region() {
4163                        if region.is_main_buffer
4164                            && (region.buffer_range.end > metadata_buffer_range.end
4165                                || cursor.is_at_end_of_excerpt())
4166                        {
4167                            break;
4168                        }
4169                        cursor.next();
4170                    }
4171                    let end_region = cursor.region();
4172
4173                    // Convert the metadata item's range into multibuffer coordinates.
4174                    let mut start_position = start_region.range.start;
4175                    let region_buffer_start = start_region.buffer_range.start;
4176                    if start_region.is_main_buffer
4177                        && metadata_buffer_range.start > region_buffer_start
4178                    {
4179                        start_position =
4180                            start_position + (metadata_buffer_range.start - region_buffer_start);
4181                        start_position = start_position.min(start_region.range.end);
4182                    }
4183
4184                    let mut end_position = self.max_position();
4185                    if let Some(end_region) = &end_region {
4186                        end_position = end_region.range.start;
4187                        debug_assert!(end_region.is_main_buffer);
4188                        let region_buffer_start = end_region.buffer_range.start;
4189                        if metadata_buffer_range.end > region_buffer_start {
4190                            end_position =
4191                                end_position + (metadata_buffer_range.end - region_buffer_start);
4192                        }
4193                        end_position = end_position.min(end_region.range.end);
4194                    }
4195
4196                    if start_position <= query_range.end && end_position >= query_range.start {
4197                        return Some((start_position..end_position, metadata, excerpt));
4198                    }
4199                }
4200                // When there are no more metadata items for this excerpt, move to the next excerpt.
4201                else {
4202                    current_excerpt_metadata.take();
4203                    if let Some((end_excerpt_id, _)) = range_end
4204                        && excerpt.id == end_excerpt_id
4205                    {
4206                        return None;
4207                    }
4208                    cursor.next_excerpt();
4209                }
4210            }
4211        })
4212    }
4213
4214    // FIXME need to make this work with inverted diffs
4215    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4216        let offset = position.to_offset(self);
4217
4218        let mut cursor = self
4219            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4220            );
4221        cursor.seek(&DimensionPair {
4222            key: offset,
4223            value: None,
4224        });
4225        cursor.seek_to_start_of_current_excerpt();
4226        let excerpt = cursor.excerpt()?;
4227
4228        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4229        let current_position = self
4230            .anchor_before(offset)
4231            .text_anchor
4232            .to_offset(&excerpt.buffer);
4233        let excerpt_end = excerpt
4234            .buffer
4235            .anchor_before(excerpt_end.min(current_position));
4236
4237        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4238            for hunk in diff.hunks_intersecting_range_rev(
4239                excerpt.range.context.start..excerpt_end,
4240                &excerpt.buffer,
4241            ) {
4242                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4243                if hunk_end >= current_position {
4244                    continue;
4245                }
4246                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4247                return Some(MultiBufferRow(start.row));
4248            }
4249        }
4250
4251        loop {
4252            cursor.prev_excerpt();
4253            let excerpt = cursor.excerpt()?;
4254
4255            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4256                continue;
4257            };
4258            let mut hunks =
4259                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4260            let Some(hunk) = hunks.next() else {
4261                continue;
4262            };
4263            let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4264            return Some(MultiBufferRow(start.row));
4265        }
4266    }
4267
4268    pub fn has_diff_hunks(&self) -> bool {
4269        self.diffs.values().any(|diff| !diff.is_empty())
4270    }
4271
4272    pub fn is_inside_word<T: ToOffset>(
4273        &self,
4274        position: T,
4275        scope_context: Option<CharScopeContext>,
4276    ) -> bool {
4277        let position = position.to_offset(self);
4278        let classifier = self
4279            .char_classifier_at(position)
4280            .scope_context(scope_context);
4281        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4282        let prev_char_kind = self
4283            .reversed_chars_at(position)
4284            .next()
4285            .map(|c| classifier.kind(c));
4286        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4287    }
4288
4289    pub fn surrounding_word<T: ToOffset>(
4290        &self,
4291        start: T,
4292        scope_context: Option<CharScopeContext>,
4293    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4294        let mut start = start.to_offset(self);
4295        let mut end = start;
4296        let mut next_chars = self.chars_at(start).peekable();
4297        let mut prev_chars = self.reversed_chars_at(start).peekable();
4298
4299        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4300
4301        let word_kind = cmp::max(
4302            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4303            next_chars.peek().copied().map(|c| classifier.kind(c)),
4304        );
4305
4306        for ch in prev_chars {
4307            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4308                start -= ch.len_utf8();
4309            } else {
4310                break;
4311            }
4312        }
4313
4314        for ch in next_chars {
4315            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4316                end += ch.len_utf8();
4317            } else {
4318                break;
4319            }
4320        }
4321
4322        (start..end, word_kind)
4323    }
4324
4325    pub fn char_kind_before<T: ToOffset>(
4326        &self,
4327        start: T,
4328        scope_context: Option<CharScopeContext>,
4329    ) -> Option<CharKind> {
4330        let start = start.to_offset(self);
4331        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4332        self.reversed_chars_at(start)
4333            .next()
4334            .map(|ch| classifier.kind(ch))
4335    }
4336
4337    pub fn is_singleton(&self) -> bool {
4338        self.singleton
4339    }
4340
4341    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4342        if self.singleton {
4343            self.excerpts
4344                .iter()
4345                .next()
4346                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4347        } else {
4348            None
4349        }
4350    }
4351
4352    pub fn len(&self) -> MultiBufferOffset {
4353        self.diff_transforms.summary().output.len
4354    }
4355
4356    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4357        MBD::from_summary(&self.text_summary())
4358    }
4359
4360    pub fn is_empty(&self) -> bool {
4361        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4362    }
4363
4364    pub fn widest_line_number(&self) -> u32 {
4365        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4366        self.excerpts.summary().widest_line_number + 1
4367    }
4368
4369    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4370        let range = range.start.to_offset(self)..range.end.to_offset(self);
4371        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4372        excerpts.seek(&range.start);
4373
4374        let mut chunk;
4375        let mut has_trailing_newline;
4376        let excerpt_bytes;
4377        if let Some(region) = excerpts.region() {
4378            let mut bytes = region.buffer.bytes_in_range(
4379                region.buffer_range.start + (range.start - region.range.start)
4380                    ..(region.buffer_range.start + (range.end - region.range.start))
4381                        .min(region.buffer_range.end),
4382            );
4383            chunk = bytes.next().unwrap_or(&[][..]);
4384            excerpt_bytes = Some(bytes);
4385            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4386            if chunk.is_empty() && has_trailing_newline {
4387                chunk = b"\n";
4388                has_trailing_newline = false;
4389            }
4390        } else {
4391            chunk = &[][..];
4392            excerpt_bytes = None;
4393            has_trailing_newline = false;
4394        };
4395
4396        MultiBufferBytes {
4397            range,
4398            cursor: excerpts,
4399            excerpt_bytes,
4400            has_trailing_newline,
4401            chunk,
4402        }
4403    }
4404
4405    pub fn reversed_bytes_in_range<T: ToOffset>(
4406        &self,
4407        range: Range<T>,
4408    ) -> ReversedMultiBufferBytes<'_> {
4409        let range = range.start.to_offset(self)..range.end.to_offset(self);
4410        let mut chunks = self.reversed_chunks_in_range(range.clone());
4411        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4412        ReversedMultiBufferBytes {
4413            range,
4414            chunks,
4415            chunk,
4416        }
4417    }
4418
4419    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4420        let mut cursor = self.cursor::<Point, Point>();
4421        cursor.seek(&Point::new(start_row.0, 0));
4422        let mut result = MultiBufferRows {
4423            point: Point::new(0, 0),
4424            is_empty: self.excerpts.is_empty(),
4425            is_singleton: self.is_singleton(),
4426            cursor,
4427        };
4428        result.seek(start_row);
4429        result
4430    }
4431
4432    pub fn chunks<T: ToOffset>(
4433        &self,
4434        range: Range<T>,
4435        language_aware: bool,
4436    ) -> MultiBufferChunks<'_> {
4437        let mut chunks = MultiBufferChunks {
4438            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4439                ..ExcerptDimension(MultiBufferOffset::ZERO),
4440            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4441            excerpts: self.excerpts.cursor(()),
4442            diff_transforms: self.diff_transforms.cursor(()),
4443            diffs: &self.diffs,
4444            diff_base_chunks: None,
4445            excerpt_chunks: None,
4446            buffer_chunk: None,
4447            language_aware,
4448        };
4449        let range = range.start.to_offset(self)..range.end.to_offset(self);
4450        chunks.seek(range);
4451        chunks
4452    }
4453
4454    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4455        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4456    }
4457
4458    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4459        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4460    }
4461
4462    pub fn clip_offset_utf16(
4463        &self,
4464        offset: MultiBufferOffsetUtf16,
4465        bias: Bias,
4466    ) -> MultiBufferOffsetUtf16 {
4467        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4468    }
4469
4470    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4471        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4472            buffer.clip_point_utf16(Unclipped(point), bias)
4473        })
4474    }
4475
4476    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4477        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4478    }
4479
4480    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4481        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4482    }
4483
4484    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4485        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4486    }
4487
4488    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4489        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4490    }
4491
4492    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4493        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4494    }
4495
4496    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4497        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4498    }
4499
4500    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4501        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4502    }
4503
4504    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4505        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4506    }
4507
4508    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4509        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4510    }
4511
4512    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4513        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4514    }
4515
4516    fn clip_dimension<MBD, BD>(
4517        &self,
4518        position: MBD,
4519        bias: Bias,
4520        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4521    ) -> MBD
4522    where
4523        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4524        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4525    {
4526        let mut cursor = self.cursor::<MBD, BD>();
4527        cursor.seek(&position);
4528        if let Some(region) = cursor.region() {
4529            if position >= region.range.end {
4530                return region.range.end;
4531            }
4532            let overshoot = position - region.range.start;
4533            let mut buffer_position = region.buffer_range.start;
4534            buffer_position += overshoot;
4535            let clipped_buffer_position =
4536                clip_buffer_position(region.buffer, buffer_position, bias);
4537            let mut position = region.range.start;
4538            position += clipped_buffer_position - region.buffer_range.start;
4539            position
4540        } else {
4541            self.max_position()
4542        }
4543    }
4544
4545    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4546        &self,
4547        key: MBR1,
4548        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4549    ) -> MBR2
4550    where
4551        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4552        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4553        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4554        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4555    {
4556        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4557        cursor.seek(&DimensionPair { key, value: None });
4558        if let Some(region) = cursor.region() {
4559            if key >= region.range.end.key {
4560                return region.range.end.value.unwrap();
4561            }
4562            let start_key = region.range.start.key;
4563            let start_value = region.range.start.value.unwrap();
4564            let buffer_start_key = region.buffer_range.start.key;
4565            let buffer_start_value = region.buffer_range.start.value.unwrap();
4566            let mut buffer_key = buffer_start_key;
4567            buffer_key += key - start_key;
4568            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4569            let mut result = start_value;
4570            result += buffer_value - buffer_start_value;
4571            result
4572        } else {
4573            self.max_position()
4574        }
4575    }
4576
4577    pub fn point_to_buffer_offset<T: ToOffset>(
4578        &self,
4579        point: T,
4580    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4581        let offset = point.to_offset(self);
4582        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4583        cursor.seek(&offset);
4584        let region = cursor.region()?;
4585        let overshoot = offset - region.range.start;
4586        let buffer_offset = region.buffer_range.start + overshoot;
4587        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4588            && region.has_trailing_newline
4589            && !region.is_main_buffer
4590        {
4591            let main_buffer_position = cursor.main_buffer_position()?;
4592            let buffer_snapshot = &cursor.excerpt()?.buffer;
4593            return Some((buffer_snapshot, main_buffer_position));
4594        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4595            return None;
4596        }
4597        Some((region.buffer, buffer_offset))
4598    }
4599
4600    pub fn point_to_buffer_point(
4601        &self,
4602        point: Point,
4603    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4604        let mut cursor = self.cursor::<Point, Point>();
4605        cursor.seek(&point);
4606        let region = cursor.region()?;
4607        let overshoot = point - region.range.start;
4608        let buffer_point = region.buffer_range.start + overshoot;
4609        let excerpt = cursor.excerpt()?;
4610        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4611            && region.has_trailing_newline
4612            && !region.is_main_buffer
4613        {
4614            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4615        } else if buffer_point > region.buffer.max_point() {
4616            return None;
4617        }
4618        Some((region.buffer, buffer_point, excerpt.id))
4619    }
4620
4621    pub fn suggested_indents(
4622        &self,
4623        rows: impl IntoIterator<Item = u32>,
4624        cx: &App,
4625    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4626        let mut result = BTreeMap::new();
4627
4628        let mut rows_for_excerpt = Vec::new();
4629        let mut cursor = self.cursor::<Point, Point>();
4630        let mut rows = rows.into_iter().peekable();
4631        let mut prev_row = u32::MAX;
4632        let mut prev_language_indent_size = IndentSize::default();
4633
4634        while let Some(row) = rows.next() {
4635            cursor.seek(&Point::new(row, 0));
4636            let Some(region) = cursor.region() else {
4637                continue;
4638            };
4639
4640            // Retrieve the language and indent size once for each disjoint region being indented.
4641            let single_indent_size = if row.saturating_sub(1) == prev_row {
4642                prev_language_indent_size
4643            } else {
4644                region
4645                    .buffer
4646                    .language_indent_size_at(Point::new(row, 0), cx)
4647            };
4648            prev_language_indent_size = single_indent_size;
4649            prev_row = row;
4650
4651            let start_buffer_row = region.buffer_range.start.row;
4652            let start_multibuffer_row = region.range.start.row;
4653            let end_multibuffer_row = region.range.end.row;
4654
4655            rows_for_excerpt.push(row);
4656            while let Some(next_row) = rows.peek().copied() {
4657                if end_multibuffer_row > next_row {
4658                    rows_for_excerpt.push(next_row);
4659                    rows.next();
4660                } else {
4661                    break;
4662                }
4663            }
4664
4665            let buffer_rows = rows_for_excerpt
4666                .drain(..)
4667                .map(|row| start_buffer_row + row - start_multibuffer_row);
4668            let buffer_indents = region
4669                .buffer
4670                .suggested_indents(buffer_rows, single_indent_size);
4671            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4672                (
4673                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4674                    indent,
4675                )
4676            });
4677            result.extend(multibuffer_indents);
4678        }
4679
4680        result
4681    }
4682
4683    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4684        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4685            let mut size = buffer.indent_size_for_line(range.start.row);
4686            size.len = size
4687                .len
4688                .min(range.end.column)
4689                .saturating_sub(range.start.column);
4690            size
4691        } else {
4692            IndentSize::spaces(0)
4693        }
4694    }
4695
4696    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4697        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4698            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4699        } else {
4700            LineIndent::spaces(0)
4701        }
4702    }
4703
4704    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4705        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4706
4707        if self.language_settings(cx).extend_comment_on_newline
4708            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4709        {
4710            let delimiters = language_scope.line_comment_prefixes();
4711            for delimiter in delimiters {
4712                if *self
4713                    .chars_at(Point::new(row.0, indent.len() as u32))
4714                    .take(delimiter.chars().count())
4715                    .collect::<String>()
4716                    .as_str()
4717                    == **delimiter
4718                {
4719                    indent.push_str(delimiter);
4720                    break;
4721                }
4722            }
4723        }
4724
4725        indent
4726    }
4727
4728    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4729    where
4730        T: ToOffset,
4731    {
4732        for char in self.reversed_chars_at(position) {
4733            if !char.is_whitespace() {
4734                return false;
4735            }
4736            if char == '\n' {
4737                return true;
4738            }
4739        }
4740        true
4741    }
4742
4743    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4744        while row.0 > 0 {
4745            row.0 -= 1;
4746            if !self.is_line_blank(row) {
4747                return Some(row);
4748            }
4749        }
4750        None
4751    }
4752
4753    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4754        if let Some((_, range)) = self.buffer_line_for_row(row) {
4755            range.end.column - range.start.column
4756        } else {
4757            0
4758        }
4759    }
4760
4761    pub fn buffer_line_for_row(
4762        &self,
4763        row: MultiBufferRow,
4764    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4765        let mut cursor = self.cursor::<Point, Point>();
4766        let point = Point::new(row.0, 0);
4767        cursor.seek(&point);
4768        let region = cursor.region()?;
4769        let overshoot = point.min(region.range.end) - region.range.start;
4770        let buffer_point = region.buffer_range.start + overshoot;
4771        if buffer_point.row > region.buffer_range.end.row {
4772            return None;
4773        }
4774        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4775        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4776            .min(region.buffer_range.end);
4777        Some((region.buffer, line_start..line_end))
4778    }
4779
4780    pub fn max_point(&self) -> Point {
4781        self.text_summary().lines
4782    }
4783
4784    pub fn max_row(&self) -> MultiBufferRow {
4785        MultiBufferRow(self.text_summary().lines.row)
4786    }
4787
4788    pub fn text_summary(&self) -> MBTextSummary {
4789        self.diff_transforms.summary().output
4790    }
4791
4792    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4793    where
4794        MBD: MultiBufferDimension + AddAssign,
4795        O: ToOffset,
4796    {
4797        let range = range.start.to_offset(self)..range.end.to_offset(self);
4798        let mut cursor = self
4799            .diff_transforms
4800            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4801        cursor.seek(&range.start, Bias::Right);
4802
4803        let Some(first_transform) = cursor.item() else {
4804            return MBD::from_summary(&MBTextSummary::default());
4805        };
4806
4807        let diff_transform_start = cursor.start().0;
4808        let diff_transform_end = cursor.end().0;
4809        let diff_start = range.start;
4810        let start_overshoot = diff_start - diff_transform_start;
4811        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4812
4813        let mut result = match first_transform {
4814            DiffTransform::BufferContent { .. } => {
4815                let excerpt_start = cursor.start().1 + start_overshoot;
4816                let excerpt_end = cursor.start().1 + end_overshoot;
4817                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4818            }
4819            DiffTransform::DeletedHunk {
4820                buffer_id,
4821                base_text_byte_range,
4822                has_trailing_newline,
4823                ..
4824            } => {
4825                let buffer_start = base_text_byte_range.start + start_overshoot;
4826                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4827                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4828                    panic!("{:?} is in non-existent deleted hunk", range.start)
4829                };
4830
4831                let include_trailing_newline =
4832                    *has_trailing_newline && range.end >= diff_transform_end;
4833                if include_trailing_newline {
4834                    buffer_end -= 1;
4835                }
4836
4837                let mut summary = base_text
4838                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4839
4840                if include_trailing_newline {
4841                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4842                        &TextSummary::newline(),
4843                    ))
4844                }
4845
4846                let mut result = MBD::default();
4847                result.add_text_dim(&summary);
4848                result
4849            }
4850        };
4851        if range.end < diff_transform_end {
4852            return result;
4853        }
4854
4855        cursor.next();
4856        result.add_mb_text_summary(
4857            &cursor
4858                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4859                .0,
4860        );
4861
4862        let Some(last_transform) = cursor.item() else {
4863            return result;
4864        };
4865
4866        let overshoot = range.end - cursor.start().0;
4867        let suffix = match last_transform {
4868            DiffTransform::BufferContent { .. } => {
4869                let end = cursor.start().1 + overshoot;
4870                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4871            }
4872            DiffTransform::DeletedHunk {
4873                base_text_byte_range,
4874                buffer_id,
4875                has_trailing_newline,
4876                ..
4877            } => {
4878                let buffer_end = base_text_byte_range.start + overshoot;
4879                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4880                    panic!("{:?} is in non-existent deleted hunk", range.end)
4881                };
4882
4883                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4884                    base_text_byte_range.start..buffer_end,
4885                );
4886                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4887                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4888                        &TextSummary::from("\n"),
4889                    ))
4890                }
4891
4892                let mut result = MBD::default();
4893                result.add_text_dim(&suffix);
4894                result
4895            }
4896        };
4897
4898        result += suffix;
4899        result
4900    }
4901
4902    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4903    where
4904        MBD: MultiBufferDimension + AddAssign,
4905    {
4906        let mut summary = MBD::default();
4907        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4908        cursor.seek(&range.start, Bias::Right);
4909        if let Some(excerpt) = cursor.item() {
4910            let mut end_before_newline = cursor.end();
4911            if excerpt.has_trailing_newline {
4912                end_before_newline -= 1;
4913            }
4914
4915            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4916            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4917            let end_in_excerpt =
4918                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4919            summary.add_text_dim(
4920                &excerpt
4921                    .buffer
4922                    .text_summary_for_range::<MBD::TextDimension, _>(
4923                        start_in_excerpt..end_in_excerpt,
4924                    ),
4925            );
4926
4927            if range.end > end_before_newline {
4928                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4929            }
4930
4931            cursor.next();
4932        }
4933
4934        if range.end > *cursor.start() {
4935            summary += cursor
4936                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4937                .0;
4938            if let Some(excerpt) = cursor.item() {
4939                range.end = cmp::max(*cursor.start(), range.end);
4940
4941                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4942                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4943                summary.add_text_dim(
4944                    &excerpt
4945                        .buffer
4946                        .text_summary_for_range::<MBD::TextDimension, _>(
4947                            excerpt_start..end_in_excerpt,
4948                        ),
4949                );
4950            }
4951        }
4952
4953        summary
4954    }
4955
4956    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4957    where
4958        MBD: MultiBufferDimension
4959            + Ord
4960            + Sub<Output = MBD::TextDimension>
4961            + AddAssign<MBD::TextDimension>,
4962        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4963    {
4964        self.summaries_for_anchors([anchor])[0]
4965    }
4966
4967    fn resolve_summary_for_anchor<MBD>(
4968        &self,
4969        anchor: &Anchor,
4970        excerpt_position: ExcerptDimension<MBD>,
4971        diff_transforms: &mut Cursor<
4972            DiffTransform,
4973            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4974        >,
4975    ) -> MBD
4976    where
4977        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4978    {
4979        loop {
4980            let transform_end_position = diff_transforms.end().0;
4981            let at_transform_end =
4982                transform_end_position == excerpt_position && diff_transforms.item().is_some();
4983            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4984                diff_transforms.next();
4985                continue;
4986            }
4987
4988            let mut position = diff_transforms.start().1;
4989            match diff_transforms.item() {
4990                Some(DiffTransform::DeletedHunk {
4991                    buffer_id,
4992                    base_text_byte_range,
4993                    ..
4994                }) => {
4995                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4996                        && let Some(base_text) =
4997                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4998                        && base_text.can_resolve(diff_base_anchor)
4999                    {
5000                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5001                        if base_text_offset >= base_text_byte_range.start
5002                            && base_text_offset <= base_text_byte_range.end
5003                        {
5004                            let position_in_hunk = base_text
5005                                .text_summary_for_range::<MBD::TextDimension, _>(
5006                                    base_text_byte_range.start..base_text_offset,
5007                                );
5008                            position.0.add_text_dim(&position_in_hunk);
5009                        } else if at_transform_end {
5010                            diff_transforms.next();
5011                            continue;
5012                        }
5013                    }
5014                }
5015                _ => {
5016                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5017                        diff_transforms.next();
5018                        continue;
5019                    }
5020                    let overshoot = excerpt_position - diff_transforms.start().0;
5021                    position += overshoot;
5022                }
5023            }
5024
5025            return position.0;
5026        }
5027    }
5028
5029    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5030        let mut cursor = self
5031            .excerpts
5032            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5033        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5034
5035        cursor.seek(&Some(locator), Bias::Left);
5036        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5037            cursor.prev();
5038        }
5039
5040        let mut position = cursor.start().1;
5041        if let Some(excerpt) = cursor.item()
5042            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5043        {
5044            let excerpt_buffer_start = excerpt
5045                .buffer
5046                .offset_for_anchor(&excerpt.range.context.start);
5047            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5048            let buffer_position = cmp::min(
5049                excerpt_buffer_end,
5050                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5051            );
5052            if buffer_position > excerpt_buffer_start {
5053                position += buffer_position - excerpt_buffer_start;
5054            }
5055        }
5056        position
5057    }
5058
5059    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5060        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5061            excerpt_id = *replacement;
5062        }
5063        excerpt_id
5064    }
5065
5066    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5067    where
5068        MBD: MultiBufferDimension
5069            + Ord
5070            + Sub<Output = MBD::TextDimension>
5071            + AddAssign<MBD::TextDimension>,
5072        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5073        I: 'a + IntoIterator<Item = &'a Anchor>,
5074    {
5075        let mut anchors = anchors.into_iter().peekable();
5076        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5077        let mut diff_transforms_cursor = self
5078            .diff_transforms
5079            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5080        diff_transforms_cursor.next();
5081
5082        let mut summaries = Vec::new();
5083        while let Some(anchor) = anchors.peek() {
5084            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5085
5086            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5087                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5088            });
5089
5090            let locator = self.excerpt_locator_for_id(excerpt_id);
5091            cursor.seek_forward(locator, Bias::Left);
5092            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5093                cursor.prev();
5094            }
5095
5096            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5097            if let Some(excerpt) = cursor.item() {
5098                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5099                    let position = self.resolve_summary_for_anchor(
5100                        &Anchor::min(),
5101                        excerpt_start_position,
5102                        &mut diff_transforms_cursor,
5103                    );
5104                    summaries.extend(excerpt_anchors.map(|_| position));
5105                    continue;
5106                }
5107                let excerpt_buffer_start = excerpt
5108                    .range
5109                    .context
5110                    .start
5111                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5112                let excerpt_buffer_end = excerpt
5113                    .range
5114                    .context
5115                    .end
5116                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5117                for (buffer_summary, anchor) in excerpt
5118                    .buffer
5119                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5120                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5121                    )
5122                {
5123                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5124                    let mut position = excerpt_start_position;
5125                    if summary > excerpt_buffer_start {
5126                        position += summary - excerpt_buffer_start;
5127                    }
5128
5129                    if diff_transforms_cursor.start().0 < position {
5130                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5131                    }
5132
5133                    summaries.push(self.resolve_summary_for_anchor(
5134                        anchor,
5135                        position,
5136                        &mut diff_transforms_cursor,
5137                    ));
5138                }
5139            } else {
5140                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5141                let position = self.resolve_summary_for_anchor(
5142                    &Anchor::max(),
5143                    excerpt_start_position,
5144                    &mut diff_transforms_cursor,
5145                );
5146                summaries.extend(excerpt_anchors.map(|_| position));
5147            }
5148        }
5149
5150        summaries
5151    }
5152
5153    pub fn dimensions_from_points<'a, MBD>(
5154        &'a self,
5155        points: impl 'a + IntoIterator<Item = Point>,
5156    ) -> impl 'a + Iterator<Item = MBD>
5157    where
5158        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5159    {
5160        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5161        cursor.seek(&DimensionPair {
5162            key: Point::default(),
5163            value: None,
5164        });
5165        let mut points = points.into_iter();
5166        iter::from_fn(move || {
5167            let point = points.next()?;
5168
5169            cursor.seek_forward(&DimensionPair {
5170                key: point,
5171                value: None,
5172            });
5173
5174            if let Some(region) = cursor.region() {
5175                let overshoot = point - region.range.start.key;
5176                let buffer_point = region.buffer_range.start + overshoot;
5177                let mut position = region.range.start.value.unwrap();
5178                position.add_text_dim(
5179                    &region
5180                        .buffer
5181                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5182                );
5183                if point == region.range.end.key && region.has_trailing_newline {
5184                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5185                }
5186                Some(position)
5187            } else {
5188                Some(MBD::from_summary(&self.text_summary()))
5189            }
5190        })
5191    }
5192
5193    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5194    where
5195        I: 'a + IntoIterator<Item = &'a Anchor>,
5196    {
5197        let mut anchors = anchors.into_iter().enumerate().peekable();
5198        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5199        cursor.next();
5200
5201        let mut result = Vec::new();
5202
5203        while let Some((_, anchor)) = anchors.peek() {
5204            let old_excerpt_id = anchor.excerpt_id;
5205
5206            // Find the location where this anchor's excerpt should be.
5207            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5208            cursor.seek_forward(&Some(old_locator), Bias::Left);
5209
5210            let next_excerpt = cursor.item();
5211            let prev_excerpt = cursor.prev_item();
5212
5213            // Process all of the anchors for this excerpt.
5214            while let Some((anchor_ix, &anchor)) =
5215                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5216            {
5217                let mut anchor = anchor;
5218
5219                // Leave min and max anchors unchanged if invalid or
5220                // if the old excerpt still exists at this location
5221                let mut kept_position = next_excerpt
5222                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5223                    || old_excerpt_id == ExcerptId::max()
5224                    || old_excerpt_id == ExcerptId::min();
5225
5226                // If the old excerpt no longer exists at this location, then attempt to
5227                // find an equivalent position for this anchor in an adjacent excerpt.
5228                if !kept_position {
5229                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5230                        if excerpt.contains(&anchor) {
5231                            anchor.excerpt_id = excerpt.id;
5232                            kept_position = true;
5233                            break;
5234                        }
5235                    }
5236                }
5237
5238                // If there's no adjacent excerpt that contains the anchor's position,
5239                // then report that the anchor has lost its position.
5240                if !kept_position {
5241                    anchor = if let Some(excerpt) = next_excerpt {
5242                        let mut text_anchor = excerpt
5243                            .range
5244                            .context
5245                            .start
5246                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5247                        if text_anchor
5248                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5249                            .is_gt()
5250                        {
5251                            text_anchor = excerpt.range.context.end;
5252                        }
5253                        Anchor::in_buffer(excerpt.id, text_anchor)
5254                    } else if let Some(excerpt) = prev_excerpt {
5255                        let mut text_anchor = excerpt
5256                            .range
5257                            .context
5258                            .end
5259                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5260                        if text_anchor
5261                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5262                            .is_lt()
5263                        {
5264                            text_anchor = excerpt.range.context.start;
5265                        }
5266                        Anchor::in_buffer(excerpt.id, text_anchor)
5267                    } else if anchor.text_anchor.bias == Bias::Left {
5268                        Anchor::min()
5269                    } else {
5270                        Anchor::max()
5271                    };
5272                }
5273
5274                result.push((anchor_ix, anchor, kept_position));
5275            }
5276        }
5277        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5278        result
5279    }
5280
5281    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5282        self.anchor_at(position, Bias::Left)
5283    }
5284
5285    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5286        self.anchor_at(position, Bias::Right)
5287    }
5288
5289    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5290        let offset = position.to_offset(self);
5291
5292        // Find the given position in the diff transforms. Determine the corresponding
5293        // offset in the excerpts, and whether the position is within a deleted hunk.
5294        let mut diff_transforms = self
5295            .diff_transforms
5296            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5297        diff_transforms.seek(&offset, Bias::Right);
5298
5299        if offset == diff_transforms.start().0
5300            && bias == Bias::Left
5301            && let Some(prev_item) = diff_transforms.prev_item()
5302            && let DiffTransform::DeletedHunk { .. } = prev_item
5303        {
5304            diff_transforms.prev();
5305        }
5306        let offset_in_transform = offset - diff_transforms.start().0;
5307        let mut excerpt_offset = diff_transforms.start().1;
5308        let mut diff_base_anchor = None;
5309        if let Some(DiffTransform::DeletedHunk {
5310            buffer_id,
5311            base_text_byte_range,
5312            has_trailing_newline,
5313            ..
5314        }) = diff_transforms.item()
5315        {
5316            let diff = self.diffs.get(buffer_id).expect("missing diff");
5317            if offset_in_transform > base_text_byte_range.len() {
5318                debug_assert!(*has_trailing_newline);
5319                bias = Bias::Right;
5320            } else {
5321                diff_base_anchor = Some(
5322                    diff.base_text()
5323                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5324                );
5325                bias = Bias::Left;
5326            }
5327        } else {
5328            excerpt_offset += MultiBufferOffset(offset_in_transform);
5329        };
5330
5331        let mut excerpts = self
5332            .excerpts
5333            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5334        excerpts.seek(&excerpt_offset, Bias::Right);
5335        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5336            excerpts.prev();
5337        }
5338        if let Some(excerpt) = excerpts.item() {
5339            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5340            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5341                overshoot -= 1;
5342                bias = Bias::Right;
5343            }
5344
5345            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5346            let text_anchor =
5347                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5348            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5349            match diff_base_anchor {
5350                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5351                None => anchor,
5352            }
5353        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5354        {
5355            Anchor::min()
5356        } else {
5357            Anchor::max()
5358        }
5359    }
5360
5361    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5362    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5363        let (excerpt, buffer, _) = self.as_singleton()?;
5364        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5365            Some(Anchor::in_buffer(*excerpt, text_anchor))
5366        } else {
5367            None
5368        }
5369    }
5370
5371    /// Returns an anchor for the given excerpt and text anchor,
5372    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5373    pub fn anchor_range_in_excerpt(
5374        &self,
5375        excerpt_id: ExcerptId,
5376        text_anchor: Range<text::Anchor>,
5377    ) -> Option<Range<Anchor>> {
5378        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5379
5380        Some(
5381            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5382                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5383        )
5384    }
5385
5386    /// Returns an anchor for the given excerpt and text anchor,
5387    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5388    pub fn anchor_in_excerpt(
5389        &self,
5390        excerpt_id: ExcerptId,
5391        text_anchor: text::Anchor,
5392    ) -> Option<Anchor> {
5393        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5394        Self::anchor_in_excerpt_(excerpt, text_anchor)
5395    }
5396
5397    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5398    pub fn anchors_in_excerpt(
5399        &self,
5400        excerpt_id: ExcerptId,
5401        text_anchors: impl IntoIterator<Item = text::Anchor>,
5402    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5403        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5404        Some(
5405            text_anchors
5406                .into_iter()
5407                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5408        )
5409    }
5410
5411    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5412        match text_anchor.buffer_id {
5413            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5414            Some(_) => return None,
5415            None if text_anchor.is_max() || text_anchor.is_min() => {
5416                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5417            }
5418            None => return None,
5419        }
5420
5421        let context = &excerpt.range.context;
5422        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5423            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5424        {
5425            return None;
5426        }
5427
5428        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5429    }
5430
5431    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5432        Some(self.excerpt(excerpt_id)?.range.context.clone())
5433    }
5434
5435    pub fn excerpt_range_for_excerpt(
5436        &self,
5437        excerpt_id: ExcerptId,
5438    ) -> Option<ExcerptRange<text::Anchor>> {
5439        Some(self.excerpt(excerpt_id)?.range.clone())
5440    }
5441
5442    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5443        if anchor.is_min() || anchor.is_max() {
5444            // todo(lw): should be `!self.is_empty()`
5445            true
5446        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5447            excerpt.buffer.can_resolve(&anchor.text_anchor)
5448        } else {
5449            false
5450        }
5451    }
5452
5453    pub fn excerpts(
5454        &self,
5455    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5456        self.excerpts
5457            .iter()
5458            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5459    }
5460
5461    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5462    where
5463        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5464        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5465    {
5466        let excerpts = self.excerpts.cursor(());
5467        let diff_transforms = self.diff_transforms.cursor(());
5468        MultiBufferCursor {
5469            excerpts,
5470            diff_transforms,
5471            diffs: &self.diffs,
5472            cached_region: None,
5473        }
5474    }
5475
5476    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5477        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5478        let mut excerpts = self
5479            .excerpts
5480            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5481        excerpts.seek(&Some(start_locator), Bias::Left);
5482        excerpts.prev();
5483
5484        let mut diff_transforms = self
5485            .diff_transforms
5486            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5487        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5488        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5489            diff_transforms.next();
5490        }
5491
5492        let excerpt = excerpts.item()?;
5493        Some(MultiBufferExcerpt {
5494            excerpt,
5495            offset: diff_transforms.start().output_dimension.0,
5496            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5497            excerpt_offset: excerpts.start().1,
5498            diff_transforms,
5499        })
5500    }
5501
5502    pub fn excerpt_boundaries_in_range<R, T>(
5503        &self,
5504        range: R,
5505    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5506    where
5507        R: RangeBounds<T>,
5508        T: ToOffset,
5509    {
5510        let start_offset;
5511        let start = match range.start_bound() {
5512            Bound::Included(start) => {
5513                start_offset = start.to_offset(self);
5514                Bound::Included(start_offset)
5515            }
5516            Bound::Excluded(_) => {
5517                panic!("not supported")
5518            }
5519            Bound::Unbounded => {
5520                start_offset = MultiBufferOffset::ZERO;
5521                Bound::Unbounded
5522            }
5523        };
5524        let end = match range.end_bound() {
5525            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5526            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5527            Bound::Unbounded => Bound::Unbounded,
5528        };
5529        let bounds = (start, end);
5530        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5531        cursor.seek(&DimensionPair {
5532            key: start_offset,
5533            value: None,
5534        });
5535
5536        if cursor
5537            .region()
5538            .is_some_and(|region| bounds.contains(&region.range.start.key))
5539        {
5540            cursor.prev_excerpt();
5541        } else {
5542            cursor.seek_to_start_of_current_excerpt();
5543        }
5544        let mut prev_region = cursor.region();
5545
5546        cursor.next_excerpt();
5547
5548        iter::from_fn(move || {
5549            loop {
5550                if self.singleton {
5551                    return None;
5552                }
5553
5554                let next_region = cursor.region()?;
5555                cursor.next_excerpt();
5556                if !bounds.contains(&next_region.range.start.key) {
5557                    prev_region = Some(next_region);
5558                    continue;
5559                }
5560
5561                let next_region_start = next_region.range.start.value.unwrap();
5562                let next_region_end = if let Some(region) = cursor.region() {
5563                    region.range.start.value.unwrap()
5564                } else {
5565                    self.max_point()
5566                };
5567
5568                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5569                    id: region.excerpt.id,
5570                    buffer: region.excerpt.buffer.clone(),
5571                    buffer_id: region.excerpt.buffer_id,
5572                    range: region.excerpt.range.clone(),
5573                    end_row: MultiBufferRow(next_region_start.row),
5574                });
5575
5576                let next = ExcerptInfo {
5577                    id: next_region.excerpt.id,
5578                    buffer: next_region.excerpt.buffer.clone(),
5579                    buffer_id: next_region.excerpt.buffer_id,
5580                    range: next_region.excerpt.range.clone(),
5581                    end_row: if next_region.excerpt.has_trailing_newline {
5582                        MultiBufferRow(next_region_end.row - 1)
5583                    } else {
5584                        MultiBufferRow(next_region_end.row)
5585                    },
5586                };
5587
5588                let row = MultiBufferRow(next_region_start.row);
5589
5590                prev_region = Some(next_region);
5591
5592                return Some(ExcerptBoundary { row, prev, next });
5593            }
5594        })
5595    }
5596
5597    pub fn edit_count(&self) -> usize {
5598        self.edit_count
5599    }
5600
5601    pub fn non_text_state_update_count(&self) -> usize {
5602        self.non_text_state_update_count
5603    }
5604
5605    /// Returns the smallest enclosing bracket ranges containing the given range or
5606    /// None if no brackets contain range or the range is not contained in a single
5607    /// excerpt
5608    ///
5609    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5610    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5611        &self,
5612        range: Range<T>,
5613        range_filter: Option<
5614            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5615        >,
5616    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5617        let range = range.start.to_offset(self)..range.end.to_offset(self);
5618        let mut excerpt = self.excerpt_containing(range.clone())?;
5619        let buffer = excerpt.buffer();
5620        let excerpt_buffer_range = excerpt.buffer_range();
5621
5622        // Filter to ranges contained in the excerpt
5623        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5624            excerpt_buffer_range.contains(&BufferOffset(open.start))
5625                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5626                && range_filter.is_none_or(|filter| {
5627                    filter(
5628                        buffer,
5629                        BufferOffset(open.start)..BufferOffset(close.end),
5630                        BufferOffset(close.start)..BufferOffset(close.end),
5631                    )
5632                })
5633        };
5634
5635        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5636            excerpt.map_range_to_buffer(range),
5637            Some(&range_filter),
5638        )?;
5639
5640        Some((
5641            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5642            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5643        ))
5644    }
5645
5646    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5647    /// not contained in a single excerpt
5648    pub fn enclosing_bracket_ranges<T: ToOffset>(
5649        &self,
5650        range: Range<T>,
5651    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5652    {
5653        let range = range.start.to_offset(self)..range.end.to_offset(self);
5654        let mut excerpt = self.excerpt_containing(range.clone())?;
5655
5656        Some(
5657            excerpt
5658                .buffer()
5659                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5660                .filter_map(move |pair| {
5661                    let open_range =
5662                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5663                    let close_range =
5664                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5665                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5666                        Some((
5667                            excerpt.map_range_from_buffer(open_range),
5668                            excerpt.map_range_from_buffer(close_range),
5669                        ))
5670                    } else {
5671                        None
5672                    }
5673                }),
5674        )
5675    }
5676
5677    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5678    /// not contained in a single excerpt
5679    pub fn text_object_ranges<T: ToOffset>(
5680        &self,
5681        range: Range<T>,
5682        options: TreeSitterOptions,
5683    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5684        let range = range.start.to_offset(self)..range.end.to_offset(self);
5685        self.excerpt_containing(range.clone())
5686            .map(|mut excerpt| {
5687                excerpt
5688                    .buffer()
5689                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5690                    .filter_map(move |(range, text_object)| {
5691                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5692                        if excerpt.contains_buffer_range(range.clone()) {
5693                            Some((excerpt.map_range_from_buffer(range), text_object))
5694                        } else {
5695                            None
5696                        }
5697                    })
5698            })
5699            .into_iter()
5700            .flatten()
5701    }
5702
5703    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5704    /// not contained in a single excerpt
5705    pub fn bracket_ranges<T: ToOffset>(
5706        &self,
5707        range: Range<T>,
5708    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5709    {
5710        let range = range.start.to_offset(self)..range.end.to_offset(self);
5711        let mut excerpt = self.excerpt_containing(range.clone())?;
5712        Some(
5713            excerpt
5714                .buffer()
5715                .bracket_ranges(excerpt.map_range_to_buffer(range))
5716                .filter_map(move |pair| {
5717                    let open_range =
5718                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5719                    let close_range =
5720                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5721                    excerpt
5722                        .contains_buffer_range(open_range.start..close_range.end)
5723                        .then(|| BracketMatch {
5724                            open_range: excerpt.map_range_from_buffer(open_range),
5725                            close_range: excerpt.map_range_from_buffer(close_range),
5726                            color_index: pair.color_index,
5727                            newline_only: pair.newline_only,
5728                            syntax_layer_depth: pair.syntax_layer_depth,
5729                        })
5730                })
5731                .map(BracketMatch::bracket_ranges),
5732        )
5733    }
5734
5735    pub fn redacted_ranges<'a, T: ToOffset>(
5736        &'a self,
5737        range: Range<T>,
5738        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5739    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5740        let range = range.start.to_offset(self)..range.end.to_offset(self);
5741        self.lift_buffer_metadata(range, move |buffer, range| {
5742            if redaction_enabled(buffer.file()) {
5743                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5744            } else {
5745                None
5746            }
5747        })
5748        .map(|(range, _, _)| range)
5749    }
5750
5751    pub fn runnable_ranges(
5752        &self,
5753        range: Range<Anchor>,
5754    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5755        let range = range.start.to_offset(self)..range.end.to_offset(self);
5756        self.lift_buffer_metadata(range, move |buffer, range| {
5757            Some(
5758                buffer
5759                    .runnable_ranges(range.clone())
5760                    .filter(move |runnable| {
5761                        runnable.run_range.start >= range.start
5762                            && runnable.run_range.end < range.end
5763                    })
5764                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5765            )
5766        })
5767        .map(|(run_range, runnable, _)| (run_range, runnable))
5768    }
5769
5770    pub fn line_indents(
5771        &self,
5772        start_row: MultiBufferRow,
5773        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5774    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5775        let max_point = self.max_point();
5776        let mut cursor = self.cursor::<Point, Point>();
5777        cursor.seek(&Point::new(start_row.0, 0));
5778        iter::from_fn(move || {
5779            let mut region = cursor.region()?;
5780            while !buffer_filter(&region.excerpt.buffer) {
5781                cursor.next();
5782                region = cursor.region()?;
5783            }
5784            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5785            let buffer_start_row =
5786                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5787
5788            let buffer_end_row = if region.is_main_buffer
5789                && (region.has_trailing_newline || region.range.end == max_point)
5790            {
5791                region.buffer_range.end.row
5792            } else {
5793                region.buffer_range.end.row.saturating_sub(1)
5794            };
5795
5796            let line_indents = region
5797                .buffer
5798                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5799            cursor.next();
5800            Some(line_indents.map(move |(buffer_row, indent)| {
5801                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5802                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5803            }))
5804        })
5805        .flatten()
5806    }
5807
5808    pub fn reversed_line_indents(
5809        &self,
5810        end_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(end_row.0, 0));
5816        iter::from_fn(move || {
5817            let mut region = cursor.region()?;
5818            while !buffer_filter(&region.excerpt.buffer) {
5819                cursor.prev();
5820                region = cursor.region()?;
5821            }
5822
5823            let buffer_start_row = region.buffer_range.start.row;
5824            let buffer_end_row = if region.is_main_buffer
5825                && (region.has_trailing_newline || region.range.end == max_point)
5826            {
5827                region.buffer_range.end.row + 1
5828            } else {
5829                region.buffer_range.end.row
5830            };
5831
5832            let overshoot = end_row.0 - region.range.start.row;
5833            let buffer_end_row =
5834                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5835
5836            let line_indents = region
5837                .buffer
5838                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5839            cursor.prev();
5840            Some(line_indents.map(move |(buffer_row, indent)| {
5841                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5842                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5843            }))
5844        })
5845        .flatten()
5846    }
5847
5848    pub async fn enclosing_indent(
5849        &self,
5850        mut target_row: MultiBufferRow,
5851    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5852        let max_row = MultiBufferRow(self.max_point().row);
5853        if target_row >= max_row {
5854            return None;
5855        }
5856
5857        let mut target_indent = self.line_indent_for_row(target_row);
5858
5859        // If the current row is at the start of an indented block, we want to return this
5860        // block as the enclosing indent.
5861        if !target_indent.is_line_empty() && target_row < max_row {
5862            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5863            if !next_line_indent.is_line_empty()
5864                && target_indent.raw_len() < next_line_indent.raw_len()
5865            {
5866                target_indent = next_line_indent;
5867                target_row.0 += 1;
5868            }
5869        }
5870
5871        const SEARCH_ROW_LIMIT: u32 = 25000;
5872        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5873        const YIELD_INTERVAL: u32 = 100;
5874
5875        let mut accessed_row_counter = 0;
5876
5877        // If there is a blank line at the current row, search for the next non indented lines
5878        if target_indent.is_line_empty() {
5879            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5880            let end =
5881                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5882
5883            let mut non_empty_line_above = None;
5884            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5885                if row < start {
5886                    break;
5887                }
5888                accessed_row_counter += 1;
5889                if accessed_row_counter == YIELD_INTERVAL {
5890                    accessed_row_counter = 0;
5891                    yield_now().await;
5892                }
5893                if !indent.is_line_empty() {
5894                    non_empty_line_above = Some((row, indent));
5895                    break;
5896                }
5897            }
5898
5899            let mut non_empty_line_below = None;
5900            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5901                if row > end {
5902                    break;
5903                }
5904                accessed_row_counter += 1;
5905                if accessed_row_counter == YIELD_INTERVAL {
5906                    accessed_row_counter = 0;
5907                    yield_now().await;
5908                }
5909                if !indent.is_line_empty() {
5910                    non_empty_line_below = Some((row, indent));
5911                    break;
5912                }
5913            }
5914
5915            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5916                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5917                    if above_indent.raw_len() >= below_indent.raw_len() {
5918                        (above_row, above_indent)
5919                    } else {
5920                        (below_row, below_indent)
5921                    }
5922                }
5923                (Some(above), None) => above,
5924                (None, Some(below)) => below,
5925                _ => return None,
5926            };
5927
5928            target_indent = indent;
5929            target_row = row;
5930        }
5931
5932        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5933        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5934
5935        let mut start_indent = None;
5936        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5937            if row < start {
5938                break;
5939            }
5940            accessed_row_counter += 1;
5941            if accessed_row_counter == YIELD_INTERVAL {
5942                accessed_row_counter = 0;
5943                yield_now().await;
5944            }
5945            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5946                start_indent = Some((row, indent));
5947                break;
5948            }
5949        }
5950        let (start_row, start_indent_size) = start_indent?;
5951
5952        let mut end_indent = (end, None);
5953        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5954            if row > end {
5955                break;
5956            }
5957            accessed_row_counter += 1;
5958            if accessed_row_counter == YIELD_INTERVAL {
5959                accessed_row_counter = 0;
5960                yield_now().await;
5961            }
5962            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5963                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5964                break;
5965            }
5966        }
5967        let (end_row, end_indent_size) = end_indent;
5968
5969        let indent = if let Some(end_indent_size) = end_indent_size {
5970            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5971                start_indent_size
5972            } else {
5973                end_indent_size
5974            }
5975        } else {
5976            start_indent_size
5977        };
5978
5979        Some((start_row..end_row, indent))
5980    }
5981
5982    pub fn indent_guides_in_range<T: ToPoint>(
5983        &self,
5984        range: Range<T>,
5985        ignore_disabled_for_language: bool,
5986        cx: &App,
5987    ) -> impl Iterator<Item = IndentGuide> {
5988        let range = range.start.to_point(self)..range.end.to_point(self);
5989        let start_row = MultiBufferRow(range.start.row);
5990        let end_row = MultiBufferRow(range.end.row);
5991
5992        let mut row_indents = self.line_indents(start_row, |buffer| {
5993            let settings =
5994                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5995            settings.indent_guides.enabled || ignore_disabled_for_language
5996        });
5997
5998        let mut result = Vec::new();
5999        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6000
6001        let mut prev_settings = None;
6002        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6003            if first_row > end_row {
6004                break;
6005            }
6006            let current_depth = indent_stack.len() as u32;
6007
6008            // Avoid retrieving the language settings repeatedly for every buffer row.
6009            if let Some((prev_buffer_id, _)) = &prev_settings
6010                && prev_buffer_id != &buffer.remote_id()
6011            {
6012                prev_settings.take();
6013            }
6014            let settings = &prev_settings
6015                .get_or_insert_with(|| {
6016                    (
6017                        buffer.remote_id(),
6018                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6019                    )
6020                })
6021                .1;
6022            let tab_size = settings.tab_size.get();
6023
6024            // When encountering empty, continue until found useful line indent
6025            // then add to the indent stack with the depth found
6026            let mut found_indent = false;
6027            let mut last_row = first_row;
6028            if line_indent.is_line_blank() {
6029                while !found_indent {
6030                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6031                        break;
6032                    };
6033                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6034                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6035                        break;
6036                    }
6037
6038                    if new_line_indent.is_line_blank() {
6039                        continue;
6040                    }
6041                    last_row = target_row.min(end_row);
6042                    line_indent = new_line_indent;
6043                    found_indent = true;
6044                    break;
6045                }
6046            } else {
6047                found_indent = true
6048            }
6049
6050            let depth = if found_indent {
6051                line_indent.len(tab_size) / tab_size
6052            } else {
6053                0
6054            };
6055
6056            match depth.cmp(&current_depth) {
6057                cmp::Ordering::Less => {
6058                    for _ in 0..(current_depth - depth) {
6059                        let mut indent = indent_stack.pop().unwrap();
6060                        if last_row != first_row {
6061                            // In this case, we landed on an empty row, had to seek forward,
6062                            // and discovered that the indent we where on is ending.
6063                            // This means that the last display row must
6064                            // be on line that ends this indent range, so we
6065                            // should display the range up to the first non-empty line
6066                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6067                        }
6068
6069                        result.push(indent)
6070                    }
6071                }
6072                cmp::Ordering::Greater => {
6073                    for next_depth in current_depth..depth {
6074                        indent_stack.push(IndentGuide {
6075                            buffer_id: buffer.remote_id(),
6076                            start_row: first_row,
6077                            end_row: last_row,
6078                            depth: next_depth,
6079                            tab_size,
6080                            settings: settings.indent_guides.clone(),
6081                        });
6082                    }
6083                }
6084                _ => {}
6085            }
6086
6087            for indent in indent_stack.iter_mut() {
6088                indent.end_row = last_row;
6089            }
6090        }
6091
6092        result.extend(indent_stack);
6093        result.into_iter()
6094    }
6095
6096    pub fn trailing_excerpt_update_count(&self) -> usize {
6097        self.trailing_excerpt_update_count
6098    }
6099
6100    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6101        self.point_to_buffer_offset(point)
6102            .and_then(|(buffer, _)| buffer.file())
6103    }
6104
6105    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6106        self.point_to_buffer_offset(offset)
6107            .and_then(|(buffer, offset)| buffer.language_at(offset))
6108    }
6109
6110    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6111        self.excerpts
6112            .first()
6113            .map(|excerpt| &excerpt.buffer)
6114            .map(|buffer| {
6115                language_settings(
6116                    buffer.language().map(|language| language.name()),
6117                    buffer.file(),
6118                    cx,
6119                )
6120            })
6121            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6122    }
6123
6124    pub fn language_settings_at<'a, T: ToOffset>(
6125        &'a self,
6126        point: T,
6127        cx: &'a App,
6128    ) -> Cow<'a, LanguageSettings> {
6129        let mut language = None;
6130        let mut file = None;
6131        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6132            language = buffer.language_at(offset);
6133            file = buffer.file();
6134        }
6135        language_settings(language.map(|l| l.name()), file, cx)
6136    }
6137
6138    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6139        self.point_to_buffer_offset(point)
6140            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6141    }
6142
6143    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6144        self.point_to_buffer_offset(point)
6145            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6146            .unwrap_or_default()
6147    }
6148
6149    pub fn language_indent_size_at<T: ToOffset>(
6150        &self,
6151        position: T,
6152        cx: &App,
6153    ) -> Option<IndentSize> {
6154        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6155        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6156    }
6157
6158    pub fn is_dirty(&self) -> bool {
6159        self.is_dirty
6160    }
6161
6162    pub fn has_deleted_file(&self) -> bool {
6163        self.has_deleted_file
6164    }
6165
6166    pub fn has_conflict(&self) -> bool {
6167        self.has_conflict
6168    }
6169
6170    pub fn has_diagnostics(&self) -> bool {
6171        self.excerpts
6172            .iter()
6173            .any(|excerpt| excerpt.buffer.has_diagnostics())
6174    }
6175
6176    pub fn diagnostic_group(
6177        &self,
6178        buffer_id: BufferId,
6179        group_id: usize,
6180    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6181        self.lift_buffer_metadata::<Point, _, _>(
6182            Point::zero()..self.max_point(),
6183            move |buffer, range| {
6184                if buffer.remote_id() != buffer_id {
6185                    return None;
6186                };
6187                Some(
6188                    buffer
6189                        .diagnostics_in_range(range, false)
6190                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6191                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6192                )
6193            },
6194        )
6195        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6196    }
6197
6198    pub fn diagnostics_in_range<'a, MBD>(
6199        &'a self,
6200        range: Range<MBD>,
6201    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6202    where
6203        MBD::TextDimension: 'a
6204            + text::ToOffset
6205            + text::FromAnchor
6206            + Sub<Output = MBD::TextDimension>
6207            + fmt::Debug
6208            + ops::Add<Output = MBD::TextDimension>
6209            + ops::AddAssign
6210            + Ord,
6211        MBD: MultiBufferDimension
6212            + Ord
6213            + Sub<Output = MBD::TextDimension>
6214            + ops::Add<MBD::TextDimension, Output = MBD>
6215            + ops::AddAssign<MBD::TextDimension>
6216            + 'a,
6217    {
6218        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6219            Some(
6220                buffer
6221                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6222                    .map(|entry| (entry.range, entry.diagnostic)),
6223            )
6224        })
6225        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6226    }
6227
6228    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6229        &'a self,
6230        range: Range<MBD>,
6231    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6232    where
6233        MBD: MultiBufferDimension
6234            + Ord
6235            + Sub<Output = MBD::TextDimension>
6236            + ops::Add<MBD::TextDimension, Output = MBD>
6237            + ops::AddAssign<MBD::TextDimension>,
6238        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6239            + ops::Add<Output = MBD::TextDimension>
6240            + text::ToOffset
6241            + text::FromAnchor
6242            + AddAssign<MBD::TextDimension>
6243            + Ord,
6244    {
6245        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6246            Some(
6247                buffer
6248                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6249                    .map(|entry| (entry.range, entry.diagnostic)),
6250            )
6251        })
6252        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6253    }
6254
6255    pub fn syntax_ancestor<T: ToOffset>(
6256        &self,
6257        range: Range<T>,
6258    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6259        let range = range.start.to_offset(self)..range.end.to_offset(self);
6260        let mut excerpt = self.excerpt_containing(range.clone())?;
6261        let node = excerpt
6262            .buffer()
6263            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6264        let node_range = node.byte_range();
6265        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6266        if !excerpt.contains_buffer_range(node_range.clone()) {
6267            return None;
6268        };
6269        Some((node, excerpt.map_range_from_buffer(node_range)))
6270    }
6271
6272    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6273        let (excerpt_id, _, buffer) = self.as_singleton()?;
6274        let outline = buffer.outline(theme);
6275        Some(Outline::new(
6276            outline
6277                .items
6278                .into_iter()
6279                .flat_map(|item| {
6280                    Some(OutlineItem {
6281                        depth: item.depth,
6282                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6283                        source_range_for_text: self
6284                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6285                        text: item.text,
6286                        highlight_ranges: item.highlight_ranges,
6287                        name_ranges: item.name_ranges,
6288                        body_range: item.body_range.and_then(|body_range| {
6289                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6290                        }),
6291                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6292                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6293                        }),
6294                    })
6295                })
6296                .collect(),
6297        ))
6298    }
6299
6300    pub fn symbols_containing<T: ToOffset>(
6301        &self,
6302        offset: T,
6303        theme: Option<&SyntaxTheme>,
6304    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6305        let anchor = self.anchor_before(offset);
6306        let excerpt @ &Excerpt {
6307            id: excerpt_id,
6308            buffer_id,
6309            ref buffer,
6310            ..
6311        } = self.excerpt(anchor.excerpt_id)?;
6312        if cfg!(debug_assertions) {
6313            match anchor.text_anchor.buffer_id {
6314                // we clearly are hitting this according to sentry, but in what situations can this occur?
6315                Some(anchor_buffer_id) => {
6316                    assert_eq!(
6317                        anchor_buffer_id, buffer_id,
6318                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6319                    )
6320                }
6321                None => assert!(anchor.is_max()),
6322            }
6323        };
6324        Some((
6325            buffer_id,
6326            buffer
6327                .symbols_containing(anchor.text_anchor, theme)
6328                .into_iter()
6329                .flat_map(|item| {
6330                    Some(OutlineItem {
6331                        depth: item.depth,
6332                        source_range_for_text: Anchor::range_in_buffer(
6333                            excerpt_id,
6334                            item.source_range_for_text,
6335                        ),
6336                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6337                        text: item.text,
6338                        highlight_ranges: item.highlight_ranges,
6339                        name_ranges: item.name_ranges,
6340                        body_range: item
6341                            .body_range
6342                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6343                        annotation_range: item
6344                            .annotation_range
6345                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6346                    })
6347                })
6348                .collect(),
6349        ))
6350    }
6351
6352    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6353        if id == ExcerptId::min() {
6354            Locator::min_ref()
6355        } else if id == ExcerptId::max() {
6356            Locator::max_ref()
6357        } else {
6358            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6359            if let Some(entry) = item
6360                && entry.id == id
6361            {
6362                return &entry.locator;
6363            }
6364            panic!("invalid excerpt id {id:?}")
6365        }
6366    }
6367
6368    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6369    fn excerpt_locators_for_ids(
6370        &self,
6371        ids: impl IntoIterator<Item = ExcerptId>,
6372    ) -> SmallVec<[Locator; 1]> {
6373        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6374        sorted_ids.sort_unstable();
6375        sorted_ids.dedup();
6376        let mut locators = SmallVec::new();
6377
6378        while sorted_ids.last() == Some(&ExcerptId::max()) {
6379            sorted_ids.pop();
6380            locators.push(Locator::max());
6381        }
6382
6383        let mut sorted_ids = sorted_ids.into_iter().peekable();
6384        locators.extend(
6385            sorted_ids
6386                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6387                .map(|_| Locator::min()),
6388        );
6389
6390        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6391        for id in sorted_ids {
6392            if cursor.seek_forward(&id, Bias::Left) {
6393                locators.push(cursor.item().unwrap().locator.clone());
6394            } else {
6395                panic!("invalid excerpt id {:?}", id);
6396            }
6397        }
6398
6399        locators.sort_unstable();
6400        locators
6401    }
6402
6403    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6404        Some(self.excerpt(excerpt_id)?.buffer_id)
6405    }
6406
6407    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6408        Some(&self.excerpt(excerpt_id)?.buffer)
6409    }
6410
6411    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6412        let mut cursor = self
6413            .excerpts
6414            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6415        let locator = self.excerpt_locator_for_id(excerpt_id);
6416        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6417        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6418            sought_exact = true;
6419            cursor.prev();
6420        } else if excerpt_id == ExcerptId::min() {
6421            sought_exact = true;
6422        }
6423        if sought_exact {
6424            let start = cursor.start().1;
6425            let end = cursor.end().1;
6426            let mut diff_transforms = self
6427                .diff_transforms
6428                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6429            diff_transforms.seek(&start, Bias::Left);
6430            let overshoot = start - diff_transforms.start().0;
6431            let start = diff_transforms.start().1 + overshoot;
6432            diff_transforms.seek(&end, Bias::Right);
6433            let overshoot = end - diff_transforms.start().0;
6434            let end = diff_transforms.start().1 + overshoot;
6435            Some(start.0..end.0)
6436        } else {
6437            None
6438        }
6439    }
6440
6441    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6442    /// to have the same excerpt id as the one passed in, with the exception of
6443    /// `ExcerptId::max()`.
6444    ///
6445    /// Callers of this function should generally use the resulting excerpt's `id` field
6446    /// afterwards.
6447    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6448        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6449        let locator = self.excerpt_locator_for_id(excerpt_id);
6450        cursor.seek(&Some(locator), Bias::Left);
6451        if let Some(excerpt) = cursor.item()
6452            && excerpt.id == excerpt_id
6453        {
6454            return Some(excerpt);
6455        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6456            cursor.prev();
6457            return cursor.item();
6458        }
6459        None
6460    }
6461
6462    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6463    pub fn excerpt_containing<T: ToOffset>(
6464        &self,
6465        range: Range<T>,
6466    ) -> Option<MultiBufferExcerpt<'_>> {
6467        let range = range.start.to_offset(self)..range.end.to_offset(self);
6468        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6469        cursor.seek(&range.start);
6470
6471        let start_excerpt = cursor.excerpt()?;
6472        if range.end != range.start {
6473            cursor.seek_forward(&range.end);
6474            if cursor.excerpt()?.id != start_excerpt.id {
6475                return None;
6476            }
6477        }
6478
6479        cursor.seek_to_start_of_current_excerpt();
6480        let region = cursor.region()?;
6481        let offset = region.range.start;
6482        let buffer_offset = start_excerpt.buffer_start_offset();
6483        let excerpt_offset = *cursor.excerpts.start();
6484        Some(MultiBufferExcerpt {
6485            diff_transforms: cursor.diff_transforms,
6486            excerpt: start_excerpt,
6487            offset,
6488            buffer_offset,
6489            excerpt_offset,
6490        })
6491    }
6492
6493    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6494        if let Some(id) = anchor.text_anchor.buffer_id {
6495            return Some(id);
6496        }
6497        let excerpt = self.excerpt_containing(anchor..anchor)?;
6498        Some(excerpt.buffer_id())
6499    }
6500
6501    pub fn selections_in_range<'a>(
6502        &'a self,
6503        range: &'a Range<Anchor>,
6504        include_local: bool,
6505    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6506        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6507        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6508        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6509        cursor.seek(start_locator, Bias::Left);
6510        cursor
6511            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6512            .flat_map(move |excerpt| {
6513                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6514                if excerpt.id == range.start.excerpt_id {
6515                    query_range.start = range.start.text_anchor;
6516                }
6517                if excerpt.id == range.end.excerpt_id {
6518                    query_range.end = range.end.text_anchor;
6519                }
6520
6521                excerpt
6522                    .buffer
6523                    .selections_in_range(query_range, include_local)
6524                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6525                        selections.map(move |selection| {
6526                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6527                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6528                            if range.start.cmp(&start, self).is_gt() {
6529                                start = range.start;
6530                            }
6531                            if range.end.cmp(&end, self).is_lt() {
6532                                end = range.end;
6533                            }
6534
6535                            (
6536                                replica_id,
6537                                line_mode,
6538                                cursor_shape,
6539                                Selection {
6540                                    id: selection.id,
6541                                    start,
6542                                    end,
6543                                    reversed: selection.reversed,
6544                                    goal: selection.goal,
6545                                },
6546                            )
6547                        })
6548                    })
6549            })
6550    }
6551
6552    pub fn show_headers(&self) -> bool {
6553        self.show_headers
6554    }
6555
6556    /// Visually annotates a position or range with the `Debug` representation of a value. The
6557    /// callsite of this function is used as a key - previous annotations will be removed.
6558    #[cfg(debug_assertions)]
6559    #[track_caller]
6560    pub fn debug<V, R>(&self, ranges: &R, value: V)
6561    where
6562        R: debug::ToMultiBufferDebugRanges,
6563        V: std::fmt::Debug,
6564    {
6565        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6566    }
6567
6568    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6569    /// debug annotations with the same key will be removed. The key is also used to determine the
6570    /// annotation's color.
6571    #[cfg(debug_assertions)]
6572    #[track_caller]
6573    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6574    where
6575        K: std::hash::Hash + 'static,
6576        R: debug::ToMultiBufferDebugRanges,
6577        V: std::fmt::Debug,
6578    {
6579        let text_ranges = ranges
6580            .to_multi_buffer_debug_ranges(self)
6581            .into_iter()
6582            .flat_map(|range| {
6583                self.range_to_buffer_ranges(range).into_iter().map(
6584                    |(buffer, range, _excerpt_id)| {
6585                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6586                    },
6587                )
6588            })
6589            .collect();
6590        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6591            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6592        });
6593    }
6594}
6595
6596#[cfg(any(test, feature = "test-support"))]
6597impl MultiBufferSnapshot {
6598    pub fn random_byte_range(
6599        &self,
6600        start_offset: MultiBufferOffset,
6601        rng: &mut impl rand::Rng,
6602    ) -> Range<MultiBufferOffset> {
6603        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6604        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6605        start..end
6606    }
6607
6608    #[cfg(any(test, feature = "test-support"))]
6609    fn check_invariants(&self) {
6610        let excerpts = self.excerpts.items(());
6611        let excerpt_ids = self.excerpt_ids.items(());
6612
6613        for (ix, excerpt) in excerpts.iter().enumerate() {
6614            if ix == 0 {
6615                if excerpt.locator <= Locator::min() {
6616                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6617                }
6618            } else if excerpt.locator <= excerpts[ix - 1].locator {
6619                panic!("excerpts are out-of-order: {:?}", excerpts);
6620            }
6621        }
6622
6623        for (ix, entry) in excerpt_ids.iter().enumerate() {
6624            if ix == 0 {
6625                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6626                    panic!("invalid first excerpt id {:?}", entry.id);
6627                }
6628            } else if entry.id <= excerpt_ids[ix - 1].id {
6629                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6630            }
6631        }
6632
6633        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6634            panic!(
6635                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6636                self.excerpts.summary().text,
6637                self.diff_transforms.summary().input,
6638                self.diff_transforms.items(()),
6639            );
6640        }
6641
6642        let mut prev_transform: Option<&DiffTransform> = None;
6643        for item in self.diff_transforms.iter() {
6644            if let DiffTransform::BufferContent {
6645                summary,
6646                inserted_hunk_info,
6647            } = item
6648            {
6649                if let Some(DiffTransform::BufferContent {
6650                    inserted_hunk_info: prev_inserted_hunk_info,
6651                    ..
6652                }) = prev_transform
6653                    && *inserted_hunk_info == *prev_inserted_hunk_info
6654                {
6655                    panic!(
6656                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6657                        self.diff_transforms.items(())
6658                    );
6659                }
6660                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6661                    panic!("empty buffer content transform");
6662                }
6663            }
6664            prev_transform = Some(item);
6665        }
6666    }
6667}
6668
6669impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6670where
6671    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6672    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6673{
6674    fn seek(&mut self, position: &MBD) {
6675        let position = OutputDimension(*position);
6676        self.cached_region.take();
6677        self.diff_transforms.seek(&position, Bias::Right);
6678        if self.diff_transforms.item().is_none()
6679            && self.diff_transforms.start().output_dimension == position
6680        {
6681            self.diff_transforms.prev();
6682        }
6683
6684        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6685        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6686            let overshoot = position - self.diff_transforms.start().output_dimension;
6687            excerpt_position += overshoot;
6688        }
6689
6690        self.excerpts.seek(&excerpt_position, Bias::Right);
6691        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6692            self.excerpts.prev();
6693        }
6694    }
6695
6696    fn seek_forward(&mut self, position: &MBD) {
6697        let position = OutputDimension(*position);
6698        self.cached_region.take();
6699        self.diff_transforms.seek_forward(&position, Bias::Right);
6700        if self.diff_transforms.item().is_none()
6701            && self.diff_transforms.start().output_dimension == position
6702        {
6703            self.diff_transforms.prev();
6704        }
6705
6706        let overshoot = position - self.diff_transforms.start().output_dimension;
6707        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6708        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6709            excerpt_position += overshoot;
6710        }
6711
6712        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6713        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6714            self.excerpts.prev();
6715        }
6716    }
6717
6718    fn next_excerpt(&mut self) {
6719        self.excerpts.next();
6720        self.seek_to_start_of_current_excerpt();
6721    }
6722
6723    fn prev_excerpt(&mut self) {
6724        self.excerpts.prev();
6725        self.seek_to_start_of_current_excerpt();
6726    }
6727
6728    fn seek_to_start_of_current_excerpt(&mut self) {
6729        self.cached_region.take();
6730        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6731        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6732            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6733            && self.diff_transforms.next_item().is_some()
6734        {
6735            self.diff_transforms.next();
6736        }
6737    }
6738
6739    fn next(&mut self) {
6740        self.cached_region.take();
6741        match self
6742            .diff_transforms
6743            .end()
6744            .excerpt_dimension
6745            .cmp(&self.excerpts.end())
6746        {
6747            cmp::Ordering::Less => self.diff_transforms.next(),
6748            cmp::Ordering::Greater => self.excerpts.next(),
6749            cmp::Ordering::Equal => {
6750                self.diff_transforms.next();
6751                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6752                    || self.diff_transforms.item().is_none()
6753                {
6754                    self.excerpts.next();
6755                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6756                    self.diff_transforms.item()
6757                    && self
6758                        .excerpts
6759                        .item()
6760                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6761                {
6762                    self.excerpts.next();
6763                }
6764            }
6765        }
6766    }
6767
6768    fn prev(&mut self) {
6769        self.cached_region.take();
6770        match self
6771            .diff_transforms
6772            .start()
6773            .excerpt_dimension
6774            .cmp(self.excerpts.start())
6775        {
6776            cmp::Ordering::Less => self.excerpts.prev(),
6777            cmp::Ordering::Greater => self.diff_transforms.prev(),
6778            cmp::Ordering::Equal => {
6779                self.diff_transforms.prev();
6780                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6781                    || self.diff_transforms.item().is_none()
6782                {
6783                    self.excerpts.prev();
6784                }
6785            }
6786        }
6787    }
6788
6789    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6790        if self.cached_region.is_none() {
6791            self.cached_region = self.build_region();
6792        }
6793        self.cached_region.clone()
6794    }
6795
6796    fn is_at_start_of_excerpt(&mut self) -> bool {
6797        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6798            return false;
6799        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6800            return true;
6801        }
6802
6803        self.diff_transforms.prev();
6804        let prev_transform = self.diff_transforms.item();
6805        self.diff_transforms.next();
6806
6807        prev_transform.is_none_or(|next_transform| {
6808            matches!(next_transform, DiffTransform::BufferContent { .. })
6809        })
6810    }
6811
6812    fn is_at_end_of_excerpt(&mut self) -> bool {
6813        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6814            return false;
6815        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6816            || self.diff_transforms.item().is_none()
6817        {
6818            return true;
6819        }
6820
6821        let next_transform = self.diff_transforms.next_item();
6822        next_transform.is_none_or(|next_transform| match next_transform {
6823            DiffTransform::BufferContent { .. } => true,
6824            DiffTransform::DeletedHunk { hunk_info, .. } => self
6825                .excerpts
6826                .item()
6827                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6828        })
6829    }
6830
6831    fn main_buffer_position(&self) -> Option<BD> {
6832        let excerpt = self.excerpts.item()?;
6833        let buffer = &excerpt.buffer;
6834        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6835        let mut buffer_start = buffer_context_start;
6836        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6837        buffer_start += overshoot;
6838        Some(buffer_start)
6839    }
6840
6841    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6842        let excerpt = self.excerpts.item()?;
6843        match self.diff_transforms.item()? {
6844            DiffTransform::DeletedHunk {
6845                buffer_id,
6846                base_text_byte_range,
6847                has_trailing_newline,
6848                hunk_info,
6849                ..
6850            } => {
6851                let diff = self.diffs.get(buffer_id)?;
6852                let buffer = diff.base_text();
6853                let mut rope_cursor = buffer.as_rope().cursor(0);
6854                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6855                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6856                let mut buffer_end = buffer_start;
6857                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6858                let start = self.diff_transforms.start().output_dimension.0;
6859                let end = self.diff_transforms.end().output_dimension.0;
6860                Some(MultiBufferRegion {
6861                    buffer,
6862                    excerpt,
6863                    has_trailing_newline: *has_trailing_newline,
6864                    is_main_buffer: false,
6865                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6866                        hunk_info.hunk_secondary_status,
6867                    )),
6868                    buffer_range: buffer_start..buffer_end,
6869                    range: start..end,
6870                })
6871            }
6872            DiffTransform::BufferContent {
6873                inserted_hunk_info, ..
6874            } => {
6875                let buffer = &excerpt.buffer;
6876                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6877
6878                let mut start = self.diff_transforms.start().output_dimension.0;
6879                let mut buffer_start = buffer_context_start;
6880                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6881                    let overshoot =
6882                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6883                    start += overshoot;
6884                } else {
6885                    let overshoot =
6886                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6887                    buffer_start += overshoot;
6888                }
6889
6890                let mut end;
6891                let mut buffer_end;
6892                let has_trailing_newline;
6893                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6894                    let overshoot =
6895                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6896                    end = self.diff_transforms.end().output_dimension.0;
6897                    buffer_end = buffer_context_start;
6898                    buffer_end += overshoot;
6899                    has_trailing_newline = false;
6900                } else {
6901                    let overshoot =
6902                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6903                    end = self.diff_transforms.start().output_dimension.0;
6904                    end += overshoot;
6905                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6906                    has_trailing_newline = excerpt.has_trailing_newline;
6907                };
6908
6909                Some(MultiBufferRegion {
6910                    buffer,
6911                    excerpt,
6912                    has_trailing_newline,
6913                    is_main_buffer: true,
6914                    diff_hunk_status: inserted_hunk_info
6915                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6916                    buffer_range: buffer_start..buffer_end,
6917                    range: start..end,
6918                })
6919            }
6920        }
6921    }
6922
6923    fn excerpt(&self) -> Option<&'a Excerpt> {
6924        self.excerpts.item()
6925    }
6926}
6927
6928impl Excerpt {
6929    fn new(
6930        id: ExcerptId,
6931        locator: Locator,
6932        buffer_id: BufferId,
6933        buffer: BufferSnapshot,
6934        range: ExcerptRange<text::Anchor>,
6935        has_trailing_newline: bool,
6936    ) -> Self {
6937        Excerpt {
6938            id,
6939            locator,
6940            max_buffer_row: range.context.end.to_point(&buffer).row,
6941            text_summary: buffer
6942                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6943            buffer_id,
6944            buffer,
6945            range,
6946            has_trailing_newline,
6947        }
6948    }
6949
6950    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6951        let content_start = self.range.context.start.to_offset(&self.buffer);
6952        let chunks_start = content_start + range.start;
6953        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6954
6955        let has_footer = self.has_trailing_newline
6956            && range.start <= self.text_summary.len
6957            && range.end > self.text_summary.len;
6958
6959        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6960
6961        ExcerptChunks {
6962            excerpt_id: self.id,
6963            content_chunks,
6964            has_footer,
6965        }
6966    }
6967
6968    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6969        let content_start = self.range.context.start.to_offset(&self.buffer);
6970        let chunks_start = content_start + range.start;
6971        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6972        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6973        excerpt_chunks.has_footer = self.has_trailing_newline
6974            && range.start <= self.text_summary.len
6975            && range.end > self.text_summary.len;
6976    }
6977
6978    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6979        if text_anchor
6980            .cmp(&self.range.context.start, &self.buffer)
6981            .is_lt()
6982        {
6983            self.range.context.start
6984        } else if text_anchor
6985            .cmp(&self.range.context.end, &self.buffer)
6986            .is_gt()
6987        {
6988            self.range.context.end
6989        } else {
6990            text_anchor
6991        }
6992    }
6993
6994    fn contains(&self, anchor: &Anchor) -> bool {
6995        (anchor.text_anchor.buffer_id == None
6996            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
6997            && self
6998                .range
6999                .context
7000                .start
7001                .cmp(&anchor.text_anchor, &self.buffer)
7002                .is_le()
7003            && self
7004                .range
7005                .context
7006                .end
7007                .cmp(&anchor.text_anchor, &self.buffer)
7008                .is_ge()
7009    }
7010
7011    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7012    fn buffer_start_offset(&self) -> BufferOffset {
7013        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7014    }
7015
7016    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7017    fn buffer_end_offset(&self) -> BufferOffset {
7018        self.buffer_start_offset() + self.text_summary.len
7019    }
7020}
7021
7022impl<'a> MultiBufferExcerpt<'a> {
7023    pub fn id(&self) -> ExcerptId {
7024        self.excerpt.id
7025    }
7026
7027    pub fn buffer_id(&self) -> BufferId {
7028        self.excerpt.buffer_id
7029    }
7030
7031    pub fn start_anchor(&self) -> Anchor {
7032        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7033    }
7034
7035    pub fn end_anchor(&self) -> Anchor {
7036        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7037    }
7038
7039    pub fn buffer(&self) -> &'a BufferSnapshot {
7040        &self.excerpt.buffer
7041    }
7042
7043    pub fn buffer_range(&self) -> Range<BufferOffset> {
7044        self.buffer_offset
7045            ..BufferOffset(
7046                self.excerpt
7047                    .range
7048                    .context
7049                    .end
7050                    .to_offset(&self.excerpt.buffer.text),
7051            )
7052    }
7053
7054    pub fn start_offset(&self) -> MultiBufferOffset {
7055        self.offset
7056    }
7057
7058    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7059    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7060        self.map_range_to_buffer(offset..offset).start
7061    }
7062
7063    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7064    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7065        self.diff_transforms
7066            .seek(&OutputDimension(range.start), Bias::Right);
7067        let start = self.map_offset_to_buffer_internal(range.start);
7068        let end = if range.end > range.start {
7069            self.diff_transforms
7070                .seek_forward(&OutputDimension(range.end), Bias::Right);
7071            self.map_offset_to_buffer_internal(range.end)
7072        } else {
7073            start
7074        };
7075        start..end
7076    }
7077
7078    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7079        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7080        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7081            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7082        };
7083        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7084        self.buffer_offset + offset_in_excerpt
7085    }
7086
7087    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7088    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7089        self.map_range_from_buffer(buffer_offset..buffer_offset)
7090            .start
7091    }
7092
7093    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7094    pub fn map_range_from_buffer(
7095        &mut self,
7096        buffer_range: Range<BufferOffset>,
7097    ) -> Range<MultiBufferOffset> {
7098        if buffer_range.start < self.buffer_offset {
7099            log::warn!(
7100                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7101            );
7102            return self.offset..self.offset;
7103        }
7104        let overshoot = buffer_range.start - self.buffer_offset;
7105        let excerpt_offset = self.excerpt_offset + overshoot;
7106        let excerpt_seek_dim = excerpt_offset;
7107        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7108        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7109            log::warn!(
7110                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7111            );
7112            return self.offset..self.offset;
7113        }
7114        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7115        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7116
7117        let end = if buffer_range.start < buffer_range.end {
7118            let overshoot = buffer_range.end - self.buffer_offset;
7119            let excerpt_offset = self.excerpt_offset + overshoot;
7120            let excerpt_seek_dim = excerpt_offset;
7121            self.diff_transforms
7122                .seek_forward(&excerpt_seek_dim, Bias::Right);
7123            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7124            // todo(lw): Clamp end to the excerpt boundaries
7125            self.diff_transforms.start().output_dimension.0 + overshoot
7126        } else {
7127            start
7128        };
7129
7130        start..end
7131    }
7132
7133    /// Returns true if the entirety of the given range is in the buffer's excerpt
7134    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7135        range.start >= self.excerpt.buffer_start_offset()
7136            && range.end <= self.excerpt.buffer_end_offset()
7137    }
7138
7139    pub fn max_buffer_row(&self) -> u32 {
7140        self.excerpt.max_buffer_row
7141    }
7142}
7143
7144impl ExcerptId {
7145    pub fn min() -> Self {
7146        Self(0)
7147    }
7148
7149    pub fn max() -> Self {
7150        Self(u32::MAX)
7151    }
7152
7153    pub fn to_proto(self) -> u64 {
7154        self.0 as _
7155    }
7156
7157    pub fn from_proto(proto: u64) -> Self {
7158        Self(proto as _)
7159    }
7160
7161    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7162        let a = snapshot.excerpt_locator_for_id(*self);
7163        let b = snapshot.excerpt_locator_for_id(*other);
7164        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7165    }
7166}
7167
7168impl From<ExcerptId> for usize {
7169    fn from(val: ExcerptId) -> Self {
7170        val.0 as usize
7171    }
7172}
7173
7174impl fmt::Debug for Excerpt {
7175    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7176        f.debug_struct("Excerpt")
7177            .field("id", &self.id)
7178            .field("locator", &self.locator)
7179            .field("buffer_id", &self.buffer_id)
7180            .field("range", &self.range)
7181            .field("text_summary", &self.text_summary)
7182            .field("has_trailing_newline", &self.has_trailing_newline)
7183            .finish()
7184    }
7185}
7186
7187impl sum_tree::Item for Excerpt {
7188    type Summary = ExcerptSummary;
7189
7190    fn summary(&self, _cx: ()) -> Self::Summary {
7191        let mut text = self.text_summary;
7192        if self.has_trailing_newline {
7193            text += TextSummary::from("\n");
7194        }
7195        ExcerptSummary {
7196            excerpt_id: self.id,
7197            excerpt_locator: self.locator.clone(),
7198            widest_line_number: self.max_buffer_row,
7199            text: text.into(),
7200        }
7201    }
7202}
7203
7204impl sum_tree::Item for ExcerptIdMapping {
7205    type Summary = ExcerptId;
7206
7207    fn summary(&self, _cx: ()) -> Self::Summary {
7208        self.id
7209    }
7210}
7211
7212impl sum_tree::KeyedItem for ExcerptIdMapping {
7213    type Key = ExcerptId;
7214
7215    fn key(&self) -> Self::Key {
7216        self.id
7217    }
7218}
7219
7220impl DiffTransform {
7221    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7222        match self {
7223            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7224            DiffTransform::BufferContent {
7225                inserted_hunk_info, ..
7226            } => *inserted_hunk_info,
7227        }
7228    }
7229}
7230
7231impl sum_tree::Item for DiffTransform {
7232    type Summary = DiffTransformSummary;
7233
7234    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7235        match self {
7236            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7237                input: *summary,
7238                output: *summary,
7239            },
7240            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7241                input: MBTextSummary::default(),
7242                output: summary.into(),
7243            },
7244        }
7245    }
7246}
7247
7248impl DiffTransformSummary {
7249    fn excerpt_len(&self) -> ExcerptOffset {
7250        ExcerptDimension(self.input.len)
7251    }
7252}
7253
7254impl sum_tree::ContextLessSummary for DiffTransformSummary {
7255    fn zero() -> Self {
7256        DiffTransformSummary {
7257            input: MBTextSummary::default(),
7258            output: MBTextSummary::default(),
7259        }
7260    }
7261
7262    fn add_summary(&mut self, other: &Self) {
7263        self.input += other.input;
7264        self.output += other.output;
7265    }
7266}
7267
7268impl sum_tree::ContextLessSummary for ExcerptId {
7269    fn zero() -> Self {
7270        Self(0)
7271    }
7272
7273    fn add_summary(&mut self, summary: &Self) {
7274        *self = cmp::max(*self, *summary);
7275    }
7276}
7277
7278impl sum_tree::ContextLessSummary for ExcerptSummary {
7279    fn zero() -> Self {
7280        Self::default()
7281    }
7282
7283    fn add_summary(&mut self, summary: &Self) {
7284        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7285        self.excerpt_locator = summary.excerpt_locator.clone();
7286        self.text += summary.text;
7287        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7288    }
7289}
7290
7291impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7292    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7293        Ord::cmp(&Some(self), cursor_location)
7294    }
7295}
7296
7297impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7298    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7299        Ord::cmp(self, &cursor_location.excerpt_locator)
7300    }
7301}
7302
7303impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7304where
7305    MBD: MultiBufferDimension + Default,
7306{
7307    fn zero(_: ()) -> Self {
7308        ExcerptDimension(MBD::default())
7309    }
7310
7311    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7312        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7313    }
7314}
7315
7316impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7317    fn zero(_cx: ()) -> Self {
7318        Default::default()
7319    }
7320
7321    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7322        *self = Some(&summary.excerpt_locator);
7323    }
7324}
7325
7326impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7327    fn zero(_cx: ()) -> Self {
7328        Default::default()
7329    }
7330
7331    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7332        *self = Some(summary.excerpt_id);
7333    }
7334}
7335
7336#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7337struct OutputDimension<T>(T);
7338
7339impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7340    fn eq(&self, other: &T) -> bool {
7341        self.0 == *other
7342    }
7343}
7344
7345impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7346    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7347        self.0.partial_cmp(other)
7348    }
7349}
7350
7351impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7352where
7353    T: ops::Sub<U, Output = R>,
7354{
7355    type Output = R;
7356
7357    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7358        self.0 - other.0
7359    }
7360}
7361
7362impl<R, T, U> ops::Add<U> for OutputDimension<T>
7363where
7364    T: ops::Add<U, Output = R>,
7365{
7366    type Output = OutputDimension<R>;
7367
7368    fn add(self, other: U) -> Self::Output {
7369        OutputDimension(self.0 + other)
7370    }
7371}
7372
7373impl<T, U> AddAssign<U> for OutputDimension<T>
7374where
7375    T: AddAssign<U>,
7376{
7377    fn add_assign(&mut self, other: U) {
7378        self.0 += other;
7379    }
7380}
7381
7382impl<T, U> SubAssign<U> for OutputDimension<T>
7383where
7384    T: SubAssign<U>,
7385{
7386    fn sub_assign(&mut self, other: U) {
7387        self.0 -= other;
7388    }
7389}
7390
7391#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7392struct ExcerptDimension<T>(T);
7393
7394impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7395    fn eq(&self, other: &T) -> bool {
7396        self.0 == *other
7397    }
7398}
7399
7400impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7401    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7402        self.0.partial_cmp(other)
7403    }
7404}
7405
7406impl ExcerptOffset {
7407    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7408        self.0.saturating_sub(other.0)
7409    }
7410}
7411
7412impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7413where
7414    T: ops::Sub<U, Output = R>,
7415{
7416    type Output = R;
7417
7418    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7419        self.0 - other.0
7420    }
7421}
7422
7423impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7424where
7425    T: ops::Add<U, Output = R>,
7426{
7427    type Output = ExcerptDimension<R>;
7428
7429    fn add(self, other: U) -> Self::Output {
7430        ExcerptDimension(self.0 + other)
7431    }
7432}
7433
7434impl<T, U> AddAssign<U> for ExcerptDimension<T>
7435where
7436    T: AddAssign<U>,
7437{
7438    fn add_assign(&mut self, other: U) {
7439        self.0 += other;
7440    }
7441}
7442
7443impl<T, U> SubAssign<U> for ExcerptDimension<T>
7444where
7445    T: SubAssign<U>,
7446{
7447    fn sub_assign(&mut self, other: U) {
7448        self.0 -= other;
7449    }
7450}
7451
7452impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7453    fn zero(_: ()) -> Self {
7454        MultiBufferOffset::ZERO
7455    }
7456
7457    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7458        *self += summary.output.len;
7459    }
7460}
7461
7462impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7463    for ExcerptDimension<MBD>
7464where
7465    MBD: MultiBufferDimension + Ord,
7466{
7467    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7468        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7469    }
7470}
7471
7472impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7473    for ExcerptDimension<MBD>
7474where
7475    MBD: MultiBufferDimension + Ord,
7476{
7477    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7478        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7479    }
7480}
7481
7482impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7483    for ExcerptDimension<MBD>
7484{
7485    fn zero(_: ()) -> Self {
7486        ExcerptDimension(MBD::default())
7487    }
7488
7489    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7490        self.0.add_mb_text_summary(&summary.input)
7491    }
7492}
7493
7494impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7495    for OutputDimension<MBD>
7496where
7497    MBD: MultiBufferDimension + Ord,
7498{
7499    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7500        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7501    }
7502}
7503
7504impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7505    for OutputDimension<MBD>
7506{
7507    fn zero(_: ()) -> Self {
7508        OutputDimension(MBD::default())
7509    }
7510
7511    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7512        self.0.add_mb_text_summary(&summary.output)
7513    }
7514}
7515
7516impl MultiBufferRows<'_> {
7517    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7518        self.point = Point::new(row, 0);
7519        self.cursor.seek(&self.point);
7520    }
7521}
7522
7523impl Iterator for MultiBufferRows<'_> {
7524    type Item = RowInfo;
7525
7526    fn next(&mut self) -> Option<Self::Item> {
7527        if self.is_empty && self.point.row == 0 {
7528            self.point += Point::new(1, 0);
7529            return Some(RowInfo {
7530                buffer_id: None,
7531                buffer_row: Some(0),
7532                multibuffer_row: Some(MultiBufferRow(0)),
7533                diff_status: None,
7534                expand_info: None,
7535                wrapped_buffer_row: None,
7536            });
7537        }
7538
7539        let mut region = self.cursor.region()?;
7540        while self.point >= region.range.end {
7541            self.cursor.next();
7542            if let Some(next_region) = self.cursor.region() {
7543                region = next_region;
7544            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7545                let multibuffer_row = MultiBufferRow(self.point.row);
7546                let last_excerpt = self
7547                    .cursor
7548                    .excerpts
7549                    .item()
7550                    .or(self.cursor.excerpts.prev_item())?;
7551                let last_row = last_excerpt
7552                    .range
7553                    .context
7554                    .end
7555                    .to_point(&last_excerpt.buffer)
7556                    .row;
7557
7558                let first_row = last_excerpt
7559                    .range
7560                    .context
7561                    .start
7562                    .to_point(&last_excerpt.buffer)
7563                    .row;
7564
7565                let expand_info = if self.is_singleton {
7566                    None
7567                } else {
7568                    let needs_expand_up = first_row == last_row
7569                        && last_row > 0
7570                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7571                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7572
7573                    if needs_expand_up && needs_expand_down {
7574                        Some(ExpandExcerptDirection::UpAndDown)
7575                    } else if needs_expand_up {
7576                        Some(ExpandExcerptDirection::Up)
7577                    } else if needs_expand_down {
7578                        Some(ExpandExcerptDirection::Down)
7579                    } else {
7580                        None
7581                    }
7582                    .map(|direction| ExpandInfo {
7583                        direction,
7584                        excerpt_id: last_excerpt.id,
7585                    })
7586                };
7587                self.point += Point::new(1, 0);
7588                return Some(RowInfo {
7589                    buffer_id: Some(last_excerpt.buffer_id),
7590                    buffer_row: Some(last_row),
7591                    multibuffer_row: Some(multibuffer_row),
7592                    diff_status: None,
7593                    wrapped_buffer_row: None,
7594                    expand_info,
7595                });
7596            } else {
7597                return None;
7598            };
7599        }
7600
7601        let overshoot = self.point - region.range.start;
7602        let buffer_point = region.buffer_range.start + overshoot;
7603        let expand_info = if self.is_singleton {
7604            None
7605        } else {
7606            let needs_expand_up = self.point.row == region.range.start.row
7607                && self.cursor.is_at_start_of_excerpt()
7608                && buffer_point.row > 0;
7609            let needs_expand_down = (region.excerpt.has_trailing_newline
7610                && self.point.row + 1 == region.range.end.row
7611                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7612                && self.cursor.is_at_end_of_excerpt()
7613                && buffer_point.row < region.buffer.max_point().row;
7614
7615            if needs_expand_up && needs_expand_down {
7616                Some(ExpandExcerptDirection::UpAndDown)
7617            } else if needs_expand_up {
7618                Some(ExpandExcerptDirection::Up)
7619            } else if needs_expand_down {
7620                Some(ExpandExcerptDirection::Down)
7621            } else {
7622                None
7623            }
7624            .map(|direction| ExpandInfo {
7625                direction,
7626                excerpt_id: region.excerpt.id,
7627            })
7628        };
7629
7630        let result = Some(RowInfo {
7631            buffer_id: Some(region.buffer.remote_id()),
7632            buffer_row: Some(buffer_point.row),
7633            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7634            diff_status: region
7635                .diff_hunk_status
7636                .filter(|_| self.point < region.range.end),
7637            expand_info,
7638            wrapped_buffer_row: None,
7639        });
7640        self.point += Point::new(1, 0);
7641        result
7642    }
7643}
7644
7645impl<'a> MultiBufferChunks<'a> {
7646    pub fn offset(&self) -> MultiBufferOffset {
7647        self.range.start
7648    }
7649
7650    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7651        self.diff_transforms.seek(&range.end, Bias::Right);
7652        let mut excerpt_end = self.diff_transforms.start().1;
7653        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7654            let overshoot = range.end - self.diff_transforms.start().0;
7655            excerpt_end += overshoot;
7656        }
7657
7658        self.diff_transforms.seek(&range.start, Bias::Right);
7659        let mut excerpt_start = self.diff_transforms.start().1;
7660        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7661            let overshoot = range.start - self.diff_transforms.start().0;
7662            excerpt_start += overshoot;
7663        }
7664
7665        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7666        self.buffer_chunk.take();
7667        self.range = range;
7668    }
7669
7670    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7671        self.excerpt_offset_range = new_range.clone();
7672        self.excerpts.seek(&new_range.start, Bias::Right);
7673        if let Some(excerpt) = self.excerpts.item() {
7674            let excerpt_start = *self.excerpts.start();
7675            if let Some(excerpt_chunks) = self
7676                .excerpt_chunks
7677                .as_mut()
7678                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7679            {
7680                excerpt.seek_chunks(
7681                    excerpt_chunks,
7682                    (self.excerpt_offset_range.start - excerpt_start)
7683                        ..(self.excerpt_offset_range.end - excerpt_start),
7684                );
7685            } else {
7686                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7687                    (self.excerpt_offset_range.start - excerpt_start)
7688                        ..(self.excerpt_offset_range.end - excerpt_start),
7689                    self.language_aware,
7690                ));
7691            }
7692        } else {
7693            self.excerpt_chunks = None;
7694        }
7695    }
7696
7697    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7698        loop {
7699            if self.excerpt_offset_range.is_empty() {
7700                return None;
7701            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7702                self.excerpt_offset_range.start += chunk.text.len();
7703                return Some(chunk);
7704            } else {
7705                self.excerpts.next();
7706                let excerpt = self.excerpts.item()?;
7707                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7708                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7709                    self.language_aware,
7710                ));
7711            }
7712        }
7713    }
7714}
7715
7716impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7717    type Item = &'a str;
7718
7719    fn next(&mut self) -> Option<Self::Item> {
7720        let mut region = self.cursor.region()?;
7721        if self.offset == region.range.start {
7722            self.cursor.prev();
7723            region = self.cursor.region()?;
7724            let start_overshoot = self.start.saturating_sub(region.range.start);
7725            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7726                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7727            ));
7728        }
7729
7730        if self.offset == region.range.end && region.has_trailing_newline {
7731            self.offset -= 1;
7732            Some("\n")
7733        } else {
7734            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7735            self.offset -= chunk.len();
7736            Some(chunk)
7737        }
7738    }
7739}
7740
7741impl<'a> Iterator for MultiBufferChunks<'a> {
7742    type Item = Chunk<'a>;
7743
7744    fn next(&mut self) -> Option<Chunk<'a>> {
7745        if self.range.start >= self.range.end {
7746            return None;
7747        }
7748        if self.range.start == self.diff_transforms.end().0 {
7749            self.diff_transforms.next();
7750        }
7751
7752        let diff_transform_start = self.diff_transforms.start().0;
7753        let diff_transform_end = self.diff_transforms.end().0;
7754        debug_assert!(
7755            self.range.start < diff_transform_end,
7756            "{:?} < {:?} of ({1:?}..{2:?})",
7757            self.range.start,
7758            diff_transform_end,
7759            diff_transform_start
7760        );
7761
7762        let diff_transform = self.diff_transforms.item()?;
7763        match diff_transform {
7764            DiffTransform::BufferContent { .. } => {
7765                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7766                    chunk
7767                } else {
7768                    let chunk = self.next_excerpt_chunk().unwrap();
7769                    self.buffer_chunk.insert(chunk)
7770                };
7771
7772                let chunk_end = self.range.start + chunk.text.len();
7773                let diff_transform_end = diff_transform_end.min(self.range.end);
7774
7775                if diff_transform_end < chunk_end {
7776                    let split_idx = diff_transform_end - self.range.start;
7777                    let (before, after) = chunk.text.split_at(split_idx);
7778                    self.range.start = diff_transform_end;
7779                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7780                    let chars = chunk.chars & mask;
7781                    let tabs = chunk.tabs & mask;
7782
7783                    chunk.text = after;
7784                    chunk.chars = chunk.chars >> split_idx;
7785                    chunk.tabs = chunk.tabs >> split_idx;
7786
7787                    Some(Chunk {
7788                        text: before,
7789                        chars,
7790                        tabs,
7791                        ..chunk.clone()
7792                    })
7793                } else {
7794                    self.range.start = chunk_end;
7795                    self.buffer_chunk.take()
7796                }
7797            }
7798            DiffTransform::DeletedHunk {
7799                buffer_id,
7800                base_text_byte_range,
7801                has_trailing_newline,
7802                ..
7803            } => {
7804                let base_text_start =
7805                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7806                let base_text_end =
7807                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7808                let base_text_end = base_text_end.min(base_text_byte_range.end);
7809
7810                let mut chunks = if let Some((_, mut chunks)) = self
7811                    .diff_base_chunks
7812                    .take()
7813                    .filter(|(id, _)| id == buffer_id)
7814                {
7815                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7816                    {
7817                        chunks.seek(base_text_start..base_text_end);
7818                    }
7819                    chunks
7820                } else {
7821                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7822                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7823                };
7824
7825                let chunk = if let Some(chunk) = chunks.next() {
7826                    self.range.start += chunk.text.len();
7827                    self.diff_base_chunks = Some((*buffer_id, chunks));
7828                    chunk
7829                } else {
7830                    debug_assert!(has_trailing_newline);
7831                    self.range.start += "\n".len();
7832                    Chunk {
7833                        text: "\n",
7834                        chars: 1u128,
7835                        ..Default::default()
7836                    }
7837                };
7838                Some(chunk)
7839            }
7840        }
7841    }
7842}
7843
7844impl MultiBufferBytes<'_> {
7845    fn consume(&mut self, len: usize) {
7846        self.range.start += len;
7847        self.chunk = &self.chunk[len..];
7848
7849        if !self.range.is_empty() && self.chunk.is_empty() {
7850            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7851                self.chunk = chunk;
7852            } else if self.has_trailing_newline {
7853                self.has_trailing_newline = false;
7854                self.chunk = b"\n";
7855            } else {
7856                self.cursor.next();
7857                if let Some(region) = self.cursor.region() {
7858                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7859                        region.buffer_range.start
7860                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7861                                .min(region.buffer_range.end),
7862                    );
7863                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7864                    self.excerpt_bytes = Some(excerpt_bytes);
7865                    self.has_trailing_newline =
7866                        region.has_trailing_newline && self.range.end >= region.range.end;
7867                    if self.chunk.is_empty() && self.has_trailing_newline {
7868                        self.has_trailing_newline = false;
7869                        self.chunk = b"\n";
7870                    }
7871                }
7872            }
7873        }
7874    }
7875}
7876
7877impl<'a> Iterator for MultiBufferBytes<'a> {
7878    type Item = &'a [u8];
7879
7880    fn next(&mut self) -> Option<Self::Item> {
7881        let chunk = self.chunk;
7882        if chunk.is_empty() {
7883            None
7884        } else {
7885            self.consume(chunk.len());
7886            Some(chunk)
7887        }
7888    }
7889}
7890
7891impl io::Read for MultiBufferBytes<'_> {
7892    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7893        let len = cmp::min(buf.len(), self.chunk.len());
7894        buf[..len].copy_from_slice(&self.chunk[..len]);
7895        if len > 0 {
7896            self.consume(len);
7897        }
7898        Ok(len)
7899    }
7900}
7901
7902impl io::Read for ReversedMultiBufferBytes<'_> {
7903    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7904        let len = cmp::min(buf.len(), self.chunk.len());
7905        buf[..len].copy_from_slice(&self.chunk[..len]);
7906        buf[..len].reverse();
7907        if len > 0 {
7908            self.range.end -= len;
7909            self.chunk = &self.chunk[..self.chunk.len() - len];
7910            if !self.range.is_empty()
7911                && self.chunk.is_empty()
7912                && let Some(chunk) = self.chunks.next()
7913            {
7914                self.chunk = chunk.as_bytes();
7915            }
7916        }
7917        Ok(len)
7918    }
7919}
7920
7921impl<'a> Iterator for ExcerptChunks<'a> {
7922    type Item = Chunk<'a>;
7923
7924    fn next(&mut self) -> Option<Self::Item> {
7925        if let Some(chunk) = self.content_chunks.next() {
7926            return Some(chunk);
7927        }
7928
7929        if self.has_footer {
7930            let text = "\n";
7931            let chars = 0b1;
7932            self.has_footer = false;
7933            return Some(Chunk {
7934                text,
7935                chars,
7936                ..Default::default()
7937            });
7938        }
7939
7940        None
7941    }
7942}
7943
7944impl ToOffset for Point {
7945    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7946        snapshot.point_to_offset(*self)
7947    }
7948    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7949        snapshot.point_to_offset_utf16(*self)
7950    }
7951}
7952
7953impl ToOffset for MultiBufferOffset {
7954    #[track_caller]
7955    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7956        assert!(
7957            *self <= snapshot.len(),
7958            "offset {} is greater than the snapshot.len() {}",
7959            self.0,
7960            snapshot.len().0,
7961        );
7962        *self
7963    }
7964    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7965        snapshot.offset_to_offset_utf16(*self)
7966    }
7967}
7968
7969impl ToOffset for MultiBufferOffsetUtf16 {
7970    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7971        snapshot.offset_utf16_to_offset(*self)
7972    }
7973
7974    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7975        *self
7976    }
7977}
7978
7979impl ToOffset for PointUtf16 {
7980    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7981        snapshot.point_utf16_to_offset(*self)
7982    }
7983    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7984        snapshot.point_utf16_to_offset_utf16(*self)
7985    }
7986}
7987
7988impl ToPoint for MultiBufferOffset {
7989    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7990        snapshot.offset_to_point(*self)
7991    }
7992    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7993        snapshot.offset_to_point_utf16(*self)
7994    }
7995}
7996
7997impl ToPoint for Point {
7998    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7999        *self
8000    }
8001    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8002        snapshot.point_to_point_utf16(*self)
8003    }
8004}
8005
8006impl ToPoint for PointUtf16 {
8007    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8008        snapshot.point_utf16_to_point(*self)
8009    }
8010    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8011        *self
8012    }
8013}
8014
8015impl From<ExcerptId> for EntityId {
8016    fn from(id: ExcerptId) -> Self {
8017        EntityId::from(id.0 as u64)
8018    }
8019}
8020
8021#[cfg(debug_assertions)]
8022pub mod debug {
8023    use super::*;
8024
8025    pub trait ToMultiBufferDebugRanges {
8026        fn to_multi_buffer_debug_ranges(
8027            &self,
8028            snapshot: &MultiBufferSnapshot,
8029        ) -> Vec<Range<MultiBufferOffset>>;
8030    }
8031
8032    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8033        fn to_multi_buffer_debug_ranges(
8034            &self,
8035            snapshot: &MultiBufferSnapshot,
8036        ) -> Vec<Range<MultiBufferOffset>> {
8037            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8038        }
8039    }
8040
8041    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8042        fn to_multi_buffer_debug_ranges(
8043            &self,
8044            snapshot: &MultiBufferSnapshot,
8045        ) -> Vec<Range<MultiBufferOffset>> {
8046            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8047                .to_multi_buffer_debug_ranges(snapshot)
8048        }
8049    }
8050
8051    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8052        fn to_multi_buffer_debug_ranges(
8053            &self,
8054            snapshot: &MultiBufferSnapshot,
8055        ) -> Vec<Range<MultiBufferOffset>> {
8056            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8057        }
8058    }
8059
8060    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8061        fn to_multi_buffer_debug_ranges(
8062            &self,
8063            snapshot: &MultiBufferSnapshot,
8064        ) -> Vec<Range<MultiBufferOffset>> {
8065            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8066        }
8067    }
8068
8069    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8070        fn to_multi_buffer_debug_ranges(
8071            &self,
8072            snapshot: &MultiBufferSnapshot,
8073        ) -> Vec<Range<MultiBufferOffset>> {
8074            self.iter()
8075                .map(|item| {
8076                    let offset = item.to_offset(snapshot);
8077                    offset..offset
8078                })
8079                .collect()
8080        }
8081    }
8082
8083    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8084        fn to_multi_buffer_debug_ranges(
8085            &self,
8086            snapshot: &MultiBufferSnapshot,
8087        ) -> Vec<Range<MultiBufferOffset>> {
8088            self.iter()
8089                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8090                .collect()
8091        }
8092    }
8093}