multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunk, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter, WeakEntity};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState,
  23    File, IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16,
  24    Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, AddAssign, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::Arc,
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58
  59pub use self::path_key::PathKey;
  60
  61#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  62pub struct ExcerptId(u32);
  63
  64/// One or more [`Buffers`](Buffer) being edited in a single view.
  65///
  66/// See <https://zed.dev/features#multi-buffers>
  67pub struct MultiBuffer {
  68    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  69    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  70    snapshot: RefCell<MultiBufferSnapshot>,
  71    /// Contains the state of the buffers being edited
  72    buffers: HashMap<BufferId, BufferState>,
  73    /// Mapping from path keys to their excerpts.
  74    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  75    /// Mapping from excerpt IDs to their path key.
  76    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  77    /// Mapping from buffer IDs to their diff states
  78    diffs: HashMap<BufferId, DiffState>,
  79    subscriptions: Topic<MultiBufferOffset>,
  80    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  81    singleton: bool,
  82    /// The history of the multi-buffer.
  83    history: History,
  84    /// The explicit title of the multi-buffer.
  85    /// If `None`, it will be derived from the underlying path or content.
  86    title: Option<String>,
  87    /// The writing capability of the multi-buffer.
  88    capability: Capability,
  89    buffer_changed_since_sync: Rc<Cell<bool>>,
  90}
  91
  92#[derive(Clone, Debug, PartialEq, Eq)]
  93pub enum Event {
  94    ExcerptsAdded {
  95        buffer: Entity<Buffer>,
  96        predecessor: ExcerptId,
  97        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  98    },
  99    ExcerptsRemoved {
 100        ids: Vec<ExcerptId>,
 101        removed_buffer_ids: Vec<BufferId>,
 102    },
 103    ExcerptsExpanded {
 104        ids: Vec<ExcerptId>,
 105    },
 106    ExcerptsEdited {
 107        excerpt_ids: Vec<ExcerptId>,
 108        buffer_ids: Vec<BufferId>,
 109    },
 110    DiffHunksToggled,
 111    Edited {
 112        edited_buffer: Option<Entity<Buffer>>,
 113    },
 114    TransactionUndone {
 115        transaction_id: TransactionId,
 116    },
 117    Reloaded,
 118    LanguageChanged(BufferId),
 119    Reparsed(BufferId),
 120    Saved,
 121    FileHandleChanged,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124    BufferDiffChanged,
 125}
 126
 127/// A diff hunk, representing a range of consequent lines in a multibuffer.
 128#[derive(Debug, Clone, PartialEq, Eq)]
 129pub struct MultiBufferDiffHunk {
 130    /// The row range in the multibuffer where this diff hunk appears.
 131    pub row_range: Range<MultiBufferRow>,
 132    /// The buffer ID that this hunk belongs to.
 133    pub buffer_id: BufferId,
 134    /// The range of the underlying buffer that this hunk corresponds to.
 135    pub buffer_range: Range<text::Anchor>,
 136    /// The excerpt that contains the diff hunk.
 137    pub excerpt_id: ExcerptId,
 138    /// The range within the buffer's diff base that this hunk corresponds to.
 139    pub diff_base_byte_range: Range<BufferOffset>,
 140    /// Whether or not this hunk also appears in the 'secondary diff'.
 141    pub secondary_status: DiffHunkSecondaryStatus,
 142    /// The word diffs for this hunk.
 143    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 163            && self.buffer_range.start.is_min()
 164            && self.buffer_range.end.is_max()
 165    }
 166
 167    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 168        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 169        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 170        start..end
 171    }
 172}
 173
 174pub type MultiBufferPoint = Point;
 175type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 176type ExcerptPoint = ExcerptDimension<Point>;
 177
 178#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 179#[serde(transparent)]
 180pub struct MultiBufferRow(pub u32);
 181
 182impl MultiBufferRow {
 183    pub const MIN: Self = Self(0);
 184    pub const MAX: Self = Self(u32::MAX);
 185}
 186
 187impl ops::Add<usize> for MultiBufferRow {
 188    type Output = Self;
 189
 190    fn add(self, rhs: usize) -> Self::Output {
 191        MultiBufferRow(self.0 + rhs as u32)
 192    }
 193}
 194
 195pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 196    type TextDimension: TextDimension;
 197    fn from_summary(summary: &MBTextSummary) -> Self;
 198
 199    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 200
 201    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 202}
 203
 204// todo(lw): MultiBufferPoint
 205impl MultiBufferDimension for Point {
 206    type TextDimension = Point;
 207    fn from_summary(summary: &MBTextSummary) -> Self {
 208        summary.lines
 209    }
 210
 211    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 212        *self += *other;
 213    }
 214
 215    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 216        *self += summary.lines;
 217    }
 218}
 219
 220// todo(lw): MultiBufferPointUtf16
 221impl MultiBufferDimension for PointUtf16 {
 222    type TextDimension = PointUtf16;
 223    fn from_summary(summary: &MBTextSummary) -> Self {
 224        summary.lines_utf16()
 225    }
 226
 227    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 228        *self += *other;
 229    }
 230
 231    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 232        *self += summary.lines_utf16();
 233    }
 234}
 235
 236#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 237pub struct MultiBufferOffset(pub usize);
 238
 239impl fmt::Display for MultiBufferOffset {
 240    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 241        write!(f, "{}", self.0)
 242    }
 243}
 244
 245impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 246    type Sampler = MultiBufferOffsetUniformSampler;
 247}
 248
 249pub struct MultiBufferOffsetUniformSampler {
 250    sampler: rand::distr::uniform::UniformUsize,
 251}
 252
 253impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 254    type X = MultiBufferOffset;
 255
 256    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 257    where
 258        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 260    {
 261        let low = *low_b.borrow();
 262        let high = *high_b.borrow();
 263        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 264        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 265    }
 266
 267    #[inline] // if the range is constant, this helps LLVM to do the
 268    // calculations at compile-time.
 269    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 270    where
 271        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 273    {
 274        let low = *low_b.borrow();
 275        let high = *high_b.borrow();
 276        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 277        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 278    }
 279
 280    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 281        MultiBufferOffset(self.sampler.sample(rng))
 282    }
 283}
 284impl MultiBufferDimension for MultiBufferOffset {
 285    type TextDimension = usize;
 286    fn from_summary(summary: &MBTextSummary) -> Self {
 287        summary.len
 288    }
 289
 290    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 291        self.0 += *other;
 292    }
 293
 294    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 295        *self += summary.len;
 296    }
 297}
 298impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 299    type TextDimension = OffsetUtf16;
 300    fn from_summary(summary: &MBTextSummary) -> Self {
 301        MultiBufferOffsetUtf16(summary.len_utf16)
 302    }
 303
 304    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 305        self.0 += *other;
 306    }
 307
 308    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 309        self.0 += summary.len_utf16;
 310    }
 311}
 312
 313#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 314pub struct BufferOffset(pub usize);
 315
 316impl TextDimension for BufferOffset {
 317    fn from_text_summary(summary: &TextSummary) -> Self {
 318        BufferOffset(usize::from_text_summary(summary))
 319    }
 320    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 321        BufferOffset(usize::from_chunk(chunk))
 322    }
 323    fn add_assign(&mut self, other: &Self) {
 324        TextDimension::add_assign(&mut self.0, &other.0);
 325    }
 326}
 327impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 328    fn zero(cx: ()) -> Self {
 329        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 330    }
 331
 332    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 333        usize::add_summary(&mut self.0, summary, cx);
 334    }
 335}
 336
 337impl Sub for BufferOffset {
 338    type Output = usize;
 339
 340    fn sub(self, other: BufferOffset) -> Self::Output {
 341        self.0 - other.0
 342    }
 343}
 344
 345impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 346    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 347        self.0 += other.key;
 348    }
 349}
 350
 351impl language::ToPoint for BufferOffset {
 352    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 353        self.0.to_point(snapshot)
 354    }
 355}
 356
 357impl language::ToPointUtf16 for BufferOffset {
 358    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 359        self.0.to_point_utf16(snapshot)
 360    }
 361}
 362
 363impl language::ToOffset for BufferOffset {
 364    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 365        self.0.to_offset(snapshot)
 366    }
 367}
 368
 369impl language::ToOffsetUtf16 for BufferOffset {
 370    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 371        self.0.to_offset_utf16(snapshot)
 372    }
 373}
 374
 375#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 376pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 377
 378impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 379    type Output = MultiBufferOffsetUtf16;
 380
 381    fn add(self, rhs: usize) -> Self::Output {
 382        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 383    }
 384}
 385
 386impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 387    fn add_assign(&mut self, rhs: OffsetUtf16) {
 388        self.0 += rhs;
 389    }
 390}
 391
 392impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 393    fn add_assign(&mut self, rhs: usize) {
 394        self.0.0 += rhs;
 395    }
 396}
 397
 398impl Sub for MultiBufferOffsetUtf16 {
 399    type Output = OffsetUtf16;
 400
 401    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 402        self.0 - other.0
 403    }
 404}
 405
 406#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 407pub struct BufferOffsetUtf16(pub OffsetUtf16);
 408
 409impl MultiBufferOffset {
 410    const ZERO: Self = Self(0);
 411    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 412        self.0.saturating_sub(other.0)
 413    }
 414    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 415        MultiBufferOffset(self.0.saturating_sub(other))
 416    }
 417}
 418
 419impl ops::Sub for MultiBufferOffset {
 420    type Output = usize;
 421
 422    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 423        self.0 - other.0
 424    }
 425}
 426
 427impl ops::Sub<usize> for MultiBufferOffset {
 428    type Output = Self;
 429
 430    fn sub(self, other: usize) -> Self::Output {
 431        MultiBufferOffset(self.0 - other)
 432    }
 433}
 434
 435impl ops::SubAssign<usize> for MultiBufferOffset {
 436    fn sub_assign(&mut self, other: usize) {
 437        self.0 -= other;
 438    }
 439}
 440
 441impl ops::Add<usize> for BufferOffset {
 442    type Output = Self;
 443
 444    fn add(self, rhs: usize) -> Self::Output {
 445        BufferOffset(self.0 + rhs)
 446    }
 447}
 448
 449impl ops::AddAssign<usize> for BufferOffset {
 450    fn add_assign(&mut self, other: usize) {
 451        self.0 += other;
 452    }
 453}
 454
 455impl ops::Add<usize> for MultiBufferOffset {
 456    type Output = Self;
 457
 458    fn add(self, rhs: usize) -> Self::Output {
 459        MultiBufferOffset(self.0 + rhs)
 460    }
 461}
 462
 463impl ops::AddAssign<usize> for MultiBufferOffset {
 464    fn add_assign(&mut self, other: usize) {
 465        self.0 += other;
 466    }
 467}
 468
 469impl ops::Add<isize> for MultiBufferOffset {
 470    type Output = Self;
 471
 472    fn add(self, rhs: isize) -> Self::Output {
 473        MultiBufferOffset((self.0 as isize + rhs) as usize)
 474    }
 475}
 476
 477impl ops::Add for MultiBufferOffset {
 478    type Output = Self;
 479
 480    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 481        MultiBufferOffset(self.0 + rhs.0)
 482    }
 483}
 484
 485impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 486    fn add_assign(&mut self, other: MultiBufferOffset) {
 487        self.0 += other.0;
 488    }
 489}
 490
 491pub trait ToOffset: 'static + fmt::Debug {
 492    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 493    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 494}
 495
 496pub trait ToPoint: 'static + fmt::Debug {
 497    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 498    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 499}
 500
 501struct BufferState {
 502    buffer: Entity<Buffer>,
 503    last_version: RefCell<clock::Global>,
 504    last_non_text_state_update_count: Cell<usize>,
 505    excerpts: Vec<Locator>,
 506    _subscriptions: [gpui::Subscription; 2],
 507}
 508
 509struct DiffState {
 510    diff: Entity<BufferDiff>,
 511    /// Whether the [`MultiBuffer`] this is associated with is inverted (i.e.
 512    /// showing additions as deletions). This is used in the side-by-side diff
 513    /// view.
 514    ///
 515    /// The [`DiffState`]s in a [`MultiBuffer`] must either be all inverted, or
 516    // all not inverted.
 517    main_buffer: Option<WeakEntity<Buffer>>,
 518    _subscription: gpui::Subscription,
 519}
 520
 521impl DiffState {
 522    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 523        DiffStateSnapshot {
 524            diff: self.diff.read(cx).snapshot(cx),
 525            main_buffer: self.main_buffer.as_ref().and_then(|main_buffer| {
 526                main_buffer
 527                    .read_with(cx, |main_buffer, _| main_buffer.snapshot())
 528                    .ok()
 529            }),
 530        }
 531    }
 532}
 533
 534#[derive(Clone)]
 535struct DiffStateSnapshot {
 536    diff: BufferDiffSnapshot,
 537    main_buffer: Option<BufferSnapshot>,
 538}
 539
 540impl std::ops::Deref for DiffStateSnapshot {
 541    type Target = BufferDiffSnapshot;
 542
 543    fn deref(&self) -> &Self::Target {
 544        &self.diff
 545    }
 546}
 547
 548impl DiffState {
 549    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 550        DiffState {
 551            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 552                BufferDiffEvent::DiffChanged {
 553                    changed_range,
 554                    base_text_changed_range: _,
 555                } => {
 556                    if let Some(changed_range) = changed_range.clone() {
 557                        this.buffer_diff_changed(diff, changed_range, cx)
 558                    }
 559                    cx.emit(Event::BufferDiffChanged);
 560                }
 561                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 562                _ => {}
 563            }),
 564            diff,
 565            main_buffer: None,
 566        }
 567    }
 568
 569    fn new_inverted(
 570        diff: Entity<BufferDiff>,
 571        base_text_buffer_id: BufferId,
 572        main_buffer: Entity<Buffer>,
 573        cx: &mut Context<MultiBuffer>,
 574    ) -> Self {
 575        let main_buffer = main_buffer.downgrade();
 576        DiffState {
 577            _subscription: cx.subscribe(&diff, {
 578                let main_buffer = main_buffer.clone();
 579                move |this, diff, event, cx| match event {
 580                    BufferDiffEvent::DiffChanged {
 581                        changed_range: _,
 582                        base_text_changed_range,
 583                    } => {
 584                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 585                            this.inverted_buffer_diff_changed(
 586                                diff,
 587                                base_text_changed_range,
 588                                base_text_buffer_id,
 589                                main_buffer.clone(),
 590                                cx,
 591                            )
 592                        }
 593                        cx.emit(Event::BufferDiffChanged);
 594                    }
 595                    BufferDiffEvent::LanguageChanged => this.inverted_buffer_diff_language_changed(
 596                        base_text_buffer_id,
 597                        diff,
 598                        main_buffer.clone(),
 599                        cx,
 600                    ),
 601                    _ => {}
 602                }
 603            }),
 604            diff,
 605            main_buffer: Some(main_buffer),
 606        }
 607    }
 608}
 609
 610/// The contents of a [`MultiBuffer`] at a single point in time.
 611#[derive(Clone, Default)]
 612pub struct MultiBufferSnapshot {
 613    excerpts: SumTree<Excerpt>,
 614    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 615    diff_transforms: SumTree<DiffTransform>,
 616    non_text_state_update_count: usize,
 617    edit_count: usize,
 618    is_dirty: bool,
 619    has_deleted_file: bool,
 620    has_conflict: bool,
 621    /// immutable fields
 622    singleton: bool,
 623    excerpt_ids: SumTree<ExcerptIdMapping>,
 624    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 625    trailing_excerpt_update_count: usize,
 626    all_diff_hunks_expanded: bool,
 627    // FIXME
 628    pub show_deleted_hunks: bool,
 629    show_headers: bool,
 630}
 631
 632// follower: None
 633// - BufferContent(Some)
 634// - BufferContent(None)
 635// - DeletedHunk
 636//
 637// follower: Some
 638// - BufferContent(Some)
 639// - BufferContent(None)
 640
 641#[derive(Debug, Clone)]
 642enum DiffTransform {
 643    // RealText
 644    BufferContent {
 645        summary: MBTextSummary,
 646        // modified_hunk_info
 647        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 648    },
 649    // ExpandedHunkText
 650    DeletedHunk {
 651        summary: TextSummary,
 652        buffer_id: BufferId,
 653        hunk_info: DiffTransformHunkInfo,
 654        base_text_byte_range: Range<usize>,
 655        has_trailing_newline: bool,
 656    },
 657}
 658
 659#[derive(Clone, Copy, Debug)]
 660struct DiffTransformHunkInfo {
 661    excerpt_id: ExcerptId,
 662    hunk_start_anchor: text::Anchor,
 663    hunk_secondary_status: DiffHunkSecondaryStatus,
 664    is_logically_deleted: bool,
 665}
 666
 667impl Eq for DiffTransformHunkInfo {}
 668
 669impl PartialEq for DiffTransformHunkInfo {
 670    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 671        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 672    }
 673}
 674
 675impl std::hash::Hash for DiffTransformHunkInfo {
 676    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 677        self.excerpt_id.hash(state);
 678        self.hunk_start_anchor.hash(state);
 679    }
 680}
 681
 682#[derive(Clone)]
 683pub struct ExcerptInfo {
 684    pub id: ExcerptId,
 685    pub buffer: BufferSnapshot,
 686    pub buffer_id: BufferId,
 687    pub range: ExcerptRange<text::Anchor>,
 688    pub end_row: MultiBufferRow,
 689}
 690
 691impl std::fmt::Debug for ExcerptInfo {
 692    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 693        f.debug_struct(type_name::<Self>())
 694            .field("id", &self.id)
 695            .field("buffer_id", &self.buffer_id)
 696            .field("path", &self.buffer.file().map(|f| f.path()))
 697            .field("range", &self.range)
 698            .finish()
 699    }
 700}
 701
 702/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 703#[derive(Debug)]
 704pub struct ExcerptBoundary {
 705    pub prev: Option<ExcerptInfo>,
 706    pub next: ExcerptInfo,
 707    /// The row in the `MultiBuffer` where the boundary is located
 708    pub row: MultiBufferRow,
 709}
 710
 711impl ExcerptBoundary {
 712    pub fn starts_new_buffer(&self) -> bool {
 713        match (self.prev.as_ref(), &self.next) {
 714            (None, _) => true,
 715            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 716        }
 717    }
 718}
 719
 720#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 721pub struct ExpandInfo {
 722    pub direction: ExpandExcerptDirection,
 723    pub excerpt_id: ExcerptId,
 724}
 725
 726#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 727pub struct RowInfo {
 728    pub buffer_id: Option<BufferId>,
 729    pub buffer_row: Option<u32>,
 730    pub multibuffer_row: Option<MultiBufferRow>,
 731    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 732    pub expand_info: Option<ExpandInfo>,
 733    pub wrapped_buffer_row: Option<u32>,
 734}
 735
 736/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 737#[derive(Clone)]
 738struct Excerpt {
 739    /// The unique identifier for this excerpt
 740    id: ExcerptId,
 741    /// The location of the excerpt in the [`MultiBuffer`]
 742    locator: Locator,
 743    /// The buffer being excerpted
 744    buffer_id: BufferId,
 745    /// A snapshot of the buffer being excerpted
 746    buffer: BufferSnapshot,
 747    /// The range of the buffer to be shown in the excerpt
 748    range: ExcerptRange<text::Anchor>,
 749    /// The last row in the excerpted slice of the buffer
 750    max_buffer_row: BufferRow,
 751    /// A summary of the text in the excerpt
 752    text_summary: TextSummary,
 753    has_trailing_newline: bool,
 754}
 755
 756/// A public view into an `Excerpt` in a [`MultiBuffer`].
 757///
 758/// Contains methods for getting the [`Buffer`] of the excerpt,
 759/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 760#[derive(Clone)]
 761pub struct MultiBufferExcerpt<'a> {
 762    excerpt: &'a Excerpt,
 763    diff_transforms:
 764        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 765    /// The offset in the multibuffer considering diff transforms.
 766    offset: MultiBufferOffset,
 767    /// The offset in the multibuffer without diff transforms.
 768    excerpt_offset: ExcerptOffset,
 769    buffer_offset: BufferOffset,
 770}
 771
 772#[derive(Clone, Debug)]
 773struct ExcerptIdMapping {
 774    id: ExcerptId,
 775    locator: Locator,
 776}
 777
 778/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 779/// These ranges are relative to the buffer itself
 780#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 781pub struct ExcerptRange<T> {
 782    /// The full range of text to be shown in the excerpt.
 783    pub context: Range<T>,
 784    /// The primary range of text to be highlighted in the excerpt.
 785    /// In a multi-buffer search, this would be the text that matched the search
 786    pub primary: Range<T>,
 787}
 788
 789impl<T: Clone> ExcerptRange<T> {
 790    pub fn new(context: Range<T>) -> Self {
 791        Self {
 792            context: context.clone(),
 793            primary: context,
 794        }
 795    }
 796}
 797
 798#[derive(Clone, Debug, Default)]
 799pub struct ExcerptSummary {
 800    excerpt_id: ExcerptId,
 801    /// The location of the last [`Excerpt`] being summarized
 802    excerpt_locator: Locator,
 803    widest_line_number: u32,
 804    text: MBTextSummary,
 805}
 806
 807#[derive(Debug, Clone)]
 808pub struct DiffTransformSummary {
 809    input: MBTextSummary,
 810    output: MBTextSummary,
 811}
 812
 813/// Summary of a string of text.
 814#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 815pub struct MBTextSummary {
 816    /// Length in bytes.
 817    pub len: MultiBufferOffset,
 818    /// Length in UTF-8.
 819    pub chars: usize,
 820    /// Length in UTF-16 code units
 821    pub len_utf16: OffsetUtf16,
 822    /// A point representing the number of lines and the length of the last line.
 823    ///
 824    /// In other words, it marks the point after the last byte in the text, (if
 825    /// EOF was a character, this would be its position).
 826    pub lines: Point,
 827    /// How many `char`s are in the first line
 828    pub first_line_chars: u32,
 829    /// How many `char`s are in the last line
 830    pub last_line_chars: u32,
 831    /// How many UTF-16 code units are in the last line
 832    pub last_line_len_utf16: u32,
 833    /// The row idx of the longest row
 834    pub longest_row: u32,
 835    /// How many `char`s are in the longest row
 836    pub longest_row_chars: u32,
 837}
 838
 839impl From<TextSummary> for MBTextSummary {
 840    fn from(summary: TextSummary) -> Self {
 841        MBTextSummary {
 842            len: MultiBufferOffset(summary.len),
 843            chars: summary.chars,
 844            len_utf16: summary.len_utf16,
 845            lines: summary.lines,
 846            first_line_chars: summary.first_line_chars,
 847            last_line_chars: summary.last_line_chars,
 848            last_line_len_utf16: summary.last_line_len_utf16,
 849            longest_row: summary.longest_row,
 850            longest_row_chars: summary.longest_row_chars,
 851        }
 852    }
 853}
 854impl From<&str> for MBTextSummary {
 855    fn from(text: &str) -> Self {
 856        MBTextSummary::from(TextSummary::from(text))
 857    }
 858}
 859
 860impl MultiBufferDimension for MBTextSummary {
 861    type TextDimension = TextSummary;
 862
 863    fn from_summary(summary: &MBTextSummary) -> Self {
 864        *summary
 865    }
 866
 867    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 868        *self += *summary;
 869    }
 870
 871    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 872        *self += *summary;
 873    }
 874}
 875
 876impl AddAssign for MBTextSummary {
 877    fn add_assign(&mut self, other: MBTextSummary) {
 878        let joined_chars = self.last_line_chars + other.first_line_chars;
 879        if joined_chars > self.longest_row_chars {
 880            self.longest_row = self.lines.row;
 881            self.longest_row_chars = joined_chars;
 882        }
 883        if other.longest_row_chars > self.longest_row_chars {
 884            self.longest_row = self.lines.row + other.longest_row;
 885            self.longest_row_chars = other.longest_row_chars;
 886        }
 887
 888        if self.lines.row == 0 {
 889            self.first_line_chars += other.first_line_chars;
 890        }
 891
 892        if other.lines.row == 0 {
 893            self.last_line_chars += other.first_line_chars;
 894            self.last_line_len_utf16 += other.last_line_len_utf16;
 895        } else {
 896            self.last_line_chars = other.last_line_chars;
 897            self.last_line_len_utf16 = other.last_line_len_utf16;
 898        }
 899
 900        self.chars += other.chars;
 901        self.len += other.len;
 902        self.len_utf16 += other.len_utf16;
 903        self.lines += other.lines;
 904    }
 905}
 906
 907impl AddAssign<TextSummary> for MBTextSummary {
 908    fn add_assign(&mut self, other: TextSummary) {
 909        *self += MBTextSummary::from(other);
 910    }
 911}
 912
 913impl MBTextSummary {
 914    pub fn lines_utf16(&self) -> PointUtf16 {
 915        PointUtf16 {
 916            row: self.lines.row,
 917            column: self.last_line_len_utf16,
 918        }
 919    }
 920}
 921
 922impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 923where
 924    K: MultiBufferDimension,
 925    V: MultiBufferDimension,
 926{
 927    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 928
 929    fn from_summary(summary: &MBTextSummary) -> Self {
 930        Self {
 931            key: K::from_summary(summary),
 932            value: Some(V::from_summary(summary)),
 933        }
 934    }
 935
 936    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 937        self.key.add_text_dim(&summary.key);
 938        if let Some(value) = &mut self.value {
 939            if let Some(other_value) = summary.value.as_ref() {
 940                value.add_text_dim(other_value);
 941            }
 942        }
 943    }
 944
 945    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 946        self.key.add_mb_text_summary(summary);
 947        if let Some(value) = &mut self.value {
 948            value.add_mb_text_summary(summary);
 949        }
 950    }
 951}
 952
 953#[derive(Clone)]
 954pub struct MultiBufferRows<'a> {
 955    point: Point,
 956    is_empty: bool,
 957    is_singleton: bool,
 958    cursor: MultiBufferCursor<'a, Point, Point>,
 959}
 960
 961pub struct MultiBufferChunks<'a> {
 962    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 963    diff_transforms:
 964        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 965    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 966    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 967    buffer_chunk: Option<Chunk<'a>>,
 968    range: Range<MultiBufferOffset>,
 969    excerpt_offset_range: Range<ExcerptOffset>,
 970    excerpt_chunks: Option<ExcerptChunks<'a>>,
 971    language_aware: bool,
 972}
 973
 974pub struct ReversedMultiBufferChunks<'a> {
 975    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 976    current_chunks: Option<rope::Chunks<'a>>,
 977    start: MultiBufferOffset,
 978    offset: MultiBufferOffset,
 979}
 980
 981pub struct MultiBufferBytes<'a> {
 982    range: Range<MultiBufferOffset>,
 983    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 984    excerpt_bytes: Option<text::Bytes<'a>>,
 985    has_trailing_newline: bool,
 986    chunk: &'a [u8],
 987}
 988
 989pub struct ReversedMultiBufferBytes<'a> {
 990    range: Range<MultiBufferOffset>,
 991    chunks: ReversedMultiBufferChunks<'a>,
 992    chunk: &'a [u8],
 993}
 994
 995#[derive(Clone)]
 996struct DiffTransforms<MBD> {
 997    output_dimension: OutputDimension<MBD>,
 998    excerpt_dimension: ExcerptDimension<MBD>,
 999}
1000
1001impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1002    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1003        Self {
1004            output_dimension: OutputDimension::zero(cx),
1005            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1006                cx,
1007            ),
1008        }
1009    }
1010
1011    fn add_summary(
1012        &mut self,
1013        summary: &'a DiffTransformSummary,
1014        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1015    ) {
1016        self.output_dimension.add_summary(summary, cx);
1017        self.excerpt_dimension.add_summary(summary, cx);
1018    }
1019}
1020
1021#[derive(Clone)]
1022struct MultiBufferCursor<'a, MBD, BD> {
1023    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1024    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1025    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1026    cached_region: Option<MultiBufferRegion<'a, MBD, BD>>,
1027}
1028
1029#[derive(Clone)]
1030struct MultiBufferRegion<'a, MBD, BD> {
1031    buffer: &'a BufferSnapshot,
1032    is_main_buffer: bool,
1033    diff_hunk_status: Option<DiffHunkStatus>,
1034    excerpt: &'a Excerpt,
1035    buffer_range: Range<BD>,
1036    range: Range<MBD>,
1037    has_trailing_newline: bool,
1038}
1039
1040struct ExcerptChunks<'a> {
1041    excerpt_id: ExcerptId,
1042    content_chunks: BufferChunks<'a>,
1043    has_footer: bool,
1044}
1045
1046#[derive(Debug)]
1047struct BufferEdit {
1048    range: Range<BufferOffset>,
1049    new_text: Arc<str>,
1050    is_insertion: bool,
1051    original_indent_column: Option<u32>,
1052    excerpt_id: ExcerptId,
1053}
1054
1055#[derive(Clone, Copy, Debug, PartialEq)]
1056enum DiffChangeKind {
1057    BufferEdited,
1058    DiffUpdated { base_changed: bool },
1059    ExpandOrCollapseHunks { expand: bool },
1060}
1061
1062#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1063pub enum ExpandExcerptDirection {
1064    Up,
1065    Down,
1066    UpAndDown,
1067}
1068
1069impl ExpandExcerptDirection {
1070    pub fn should_expand_up(&self) -> bool {
1071        match self {
1072            ExpandExcerptDirection::Up => true,
1073            ExpandExcerptDirection::Down => false,
1074            ExpandExcerptDirection::UpAndDown => true,
1075        }
1076    }
1077
1078    pub fn should_expand_down(&self) -> bool {
1079        match self {
1080            ExpandExcerptDirection::Up => false,
1081            ExpandExcerptDirection::Down => true,
1082            ExpandExcerptDirection::UpAndDown => true,
1083        }
1084    }
1085}
1086
1087#[derive(Clone, Debug, PartialEq)]
1088pub struct IndentGuide {
1089    pub buffer_id: BufferId,
1090    pub start_row: MultiBufferRow,
1091    pub end_row: MultiBufferRow,
1092    pub depth: u32,
1093    pub tab_size: u32,
1094    pub settings: IndentGuideSettings,
1095}
1096
1097impl IndentGuide {
1098    pub fn indent_level(&self) -> u32 {
1099        self.depth * self.tab_size
1100    }
1101}
1102
1103impl MultiBuffer {
1104    pub fn new(capability: Capability) -> Self {
1105        Self::new_(
1106            capability,
1107            MultiBufferSnapshot {
1108                show_headers: true,
1109                show_deleted_hunks: true,
1110                ..MultiBufferSnapshot::default()
1111            },
1112        )
1113    }
1114
1115    pub fn without_headers(capability: Capability) -> Self {
1116        Self::new_(capability, Default::default())
1117    }
1118
1119    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1120        let mut this = Self::new_(
1121            buffer.read(cx).capability(),
1122            MultiBufferSnapshot {
1123                singleton: true,
1124                show_deleted_hunks: true,
1125                ..MultiBufferSnapshot::default()
1126            },
1127        );
1128        this.singleton = true;
1129        let buffer_id = buffer.read(cx).remote_id();
1130        this.push_excerpts(
1131            buffer,
1132            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1133                buffer_id,
1134            ))],
1135            cx,
1136        );
1137        this
1138    }
1139
1140    #[inline]
1141    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1142        Self {
1143            snapshot: RefCell::new(snapshot),
1144            buffers: Default::default(),
1145            diffs: HashMap::default(),
1146            subscriptions: Topic::default(),
1147            singleton: false,
1148            capability,
1149            title: None,
1150            excerpts_by_path: Default::default(),
1151            paths_by_excerpt: Default::default(),
1152            buffer_changed_since_sync: Default::default(),
1153            history: History::default(),
1154        }
1155    }
1156
1157    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1158        let mut buffers = HashMap::default();
1159        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1160        for (buffer_id, buffer_state) in self.buffers.iter() {
1161            buffer_state.buffer.update(new_cx, |buffer, _| {
1162                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1163            });
1164            buffers.insert(
1165                *buffer_id,
1166                BufferState {
1167                    buffer: buffer_state.buffer.clone(),
1168                    last_version: buffer_state.last_version.clone(),
1169                    last_non_text_state_update_count: buffer_state
1170                        .last_non_text_state_update_count
1171                        .clone(),
1172                    excerpts: buffer_state.excerpts.clone(),
1173                    _subscriptions: [
1174                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1175                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1176                    ],
1177                },
1178            );
1179        }
1180        let mut diff_bases = HashMap::default();
1181        for (buffer_id, diff) in self.diffs.iter() {
1182            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1183        }
1184        Self {
1185            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1186            buffers: buffers,
1187            excerpts_by_path: Default::default(),
1188            paths_by_excerpt: Default::default(),
1189            diffs: diff_bases,
1190            subscriptions: Default::default(),
1191            singleton: self.singleton,
1192            capability: self.capability,
1193            history: self.history.clone(),
1194            title: self.title.clone(),
1195            buffer_changed_since_sync,
1196        }
1197    }
1198
1199    pub fn set_group_interval(&mut self, group_interval: Duration) {
1200        self.history.set_group_interval(group_interval);
1201    }
1202
1203    pub fn with_title(mut self, title: String) -> Self {
1204        self.title = Some(title);
1205        self
1206    }
1207
1208    pub fn read_only(&self) -> bool {
1209        self.capability == Capability::ReadOnly
1210    }
1211
1212    /// Returns an up-to-date snapshot of the MultiBuffer.
1213    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1214        self.sync(cx);
1215        self.snapshot.borrow().clone()
1216    }
1217
1218    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1219        self.sync(cx);
1220        self.snapshot.borrow()
1221    }
1222
1223    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1224        if self.singleton {
1225            Some(self.buffers.values().next().unwrap().buffer.clone())
1226        } else {
1227            None
1228        }
1229    }
1230
1231    pub fn is_singleton(&self) -> bool {
1232        self.singleton
1233    }
1234
1235    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1236        self.subscriptions.subscribe()
1237    }
1238
1239    pub fn is_dirty(&self, cx: &App) -> bool {
1240        self.read(cx).is_dirty()
1241    }
1242
1243    pub fn has_deleted_file(&self, cx: &App) -> bool {
1244        self.read(cx).has_deleted_file()
1245    }
1246
1247    pub fn has_conflict(&self, cx: &App) -> bool {
1248        self.read(cx).has_conflict()
1249    }
1250
1251    // The `is_empty` signature doesn't match what clippy expects
1252    #[allow(clippy::len_without_is_empty)]
1253    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1254        self.read(cx).len()
1255    }
1256
1257    pub fn is_empty(&self) -> bool {
1258        self.buffers.is_empty()
1259    }
1260
1261    pub fn edit<I, S, T>(
1262        &mut self,
1263        edits: I,
1264        autoindent_mode: Option<AutoindentMode>,
1265        cx: &mut Context<Self>,
1266    ) where
1267        I: IntoIterator<Item = (Range<S>, T)>,
1268        S: ToOffset,
1269        T: Into<Arc<str>>,
1270    {
1271        if self.read_only() || self.buffers.is_empty() {
1272            return;
1273        }
1274        self.sync_mut(cx);
1275        let edits = edits
1276            .into_iter()
1277            .map(|(range, new_text)| {
1278                let mut range = range.start.to_offset(self.snapshot.get_mut())
1279                    ..range.end.to_offset(self.snapshot.get_mut());
1280                if range.start > range.end {
1281                    mem::swap(&mut range.start, &mut range.end);
1282                }
1283                (range, new_text.into())
1284            })
1285            .collect::<Vec<_>>();
1286
1287        return edit_internal(self, edits, autoindent_mode, cx);
1288
1289        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1290        fn edit_internal(
1291            this: &mut MultiBuffer,
1292            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1293            mut autoindent_mode: Option<AutoindentMode>,
1294            cx: &mut Context<MultiBuffer>,
1295        ) {
1296            let original_indent_columns = match &mut autoindent_mode {
1297                Some(AutoindentMode::Block {
1298                    original_indent_columns,
1299                }) => mem::take(original_indent_columns),
1300                _ => Default::default(),
1301            };
1302
1303            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1304                edits,
1305                this.snapshot.get_mut(),
1306                &original_indent_columns,
1307            );
1308
1309            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1310            for (buffer_id, mut edits) in buffer_edits {
1311                buffer_ids.push(buffer_id);
1312                edits.sort_by_key(|edit| edit.range.start);
1313                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1314                    let mut edits = edits.into_iter().peekable();
1315                    let mut insertions = Vec::new();
1316                    let mut original_indent_columns = Vec::new();
1317                    let mut deletions = Vec::new();
1318                    let empty_str: Arc<str> = Arc::default();
1319                    while let Some(BufferEdit {
1320                        mut range,
1321                        mut new_text,
1322                        mut is_insertion,
1323                        original_indent_column,
1324                        excerpt_id,
1325                    }) = edits.next()
1326                    {
1327                        while let Some(BufferEdit {
1328                            range: next_range,
1329                            is_insertion: next_is_insertion,
1330                            new_text: next_new_text,
1331                            excerpt_id: next_excerpt_id,
1332                            ..
1333                        }) = edits.peek()
1334                        {
1335                            if range.end >= next_range.start {
1336                                range.end = cmp::max(next_range.end, range.end);
1337                                is_insertion |= *next_is_insertion;
1338                                if excerpt_id == *next_excerpt_id {
1339                                    new_text = format!("{new_text}{next_new_text}").into();
1340                                }
1341                                edits.next();
1342                            } else {
1343                                break;
1344                            }
1345                        }
1346
1347                        if is_insertion {
1348                            original_indent_columns.push(original_indent_column);
1349                            insertions.push((
1350                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1351                                new_text.clone(),
1352                            ));
1353                        } else if !range.is_empty() {
1354                            deletions.push((
1355                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1356                                empty_str.clone(),
1357                            ));
1358                        }
1359                    }
1360
1361                    let deletion_autoindent_mode =
1362                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1363                            Some(AutoindentMode::Block {
1364                                original_indent_columns: Default::default(),
1365                            })
1366                        } else {
1367                            autoindent_mode.clone()
1368                        };
1369                    let insertion_autoindent_mode =
1370                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1371                            Some(AutoindentMode::Block {
1372                                original_indent_columns,
1373                            })
1374                        } else {
1375                            autoindent_mode.clone()
1376                        };
1377
1378                    buffer.edit(deletions, deletion_autoindent_mode, cx);
1379                    buffer.edit(insertions, insertion_autoindent_mode, cx);
1380                })
1381            }
1382
1383            cx.emit(Event::ExcerptsEdited {
1384                excerpt_ids: edited_excerpt_ids,
1385                buffer_ids,
1386            });
1387        }
1388    }
1389
1390    fn convert_edits_to_buffer_edits(
1391        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1392        snapshot: &MultiBufferSnapshot,
1393        original_indent_columns: &[Option<u32>],
1394    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1395        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1396        let mut edited_excerpt_ids = Vec::new();
1397        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1398        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1399            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1400
1401            cursor.seek(&range.start);
1402            let mut start_region = cursor.region().expect("start offset out of bounds");
1403            if !start_region.is_main_buffer {
1404                cursor.next();
1405                if let Some(region) = cursor.region() {
1406                    start_region = region;
1407                } else {
1408                    continue;
1409                }
1410            }
1411
1412            if range.end < start_region.range.start {
1413                continue;
1414            }
1415
1416            if range.end > start_region.range.end {
1417                cursor.seek_forward(&range.end);
1418            }
1419            let mut end_region = cursor.region().expect("end offset out of bounds");
1420            if !end_region.is_main_buffer {
1421                cursor.prev();
1422                if let Some(region) = cursor.region() {
1423                    end_region = region;
1424                } else {
1425                    continue;
1426                }
1427            }
1428
1429            if range.start > end_region.range.end {
1430                continue;
1431            }
1432
1433            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1434            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1435            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1436                .min(start_region.buffer_range.end);
1437            let buffer_end =
1438                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1439
1440            if start_region.excerpt.id == end_region.excerpt.id {
1441                if start_region.is_main_buffer {
1442                    edited_excerpt_ids.push(start_region.excerpt.id);
1443                    buffer_edits
1444                        .entry(start_region.buffer.remote_id())
1445                        .or_default()
1446                        .push(BufferEdit {
1447                            range: buffer_start..buffer_end,
1448                            new_text,
1449                            is_insertion: true,
1450                            original_indent_column,
1451                            excerpt_id: start_region.excerpt.id,
1452                        });
1453                }
1454            } else {
1455                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1456                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1457                if start_region.is_main_buffer {
1458                    edited_excerpt_ids.push(start_region.excerpt.id);
1459                    buffer_edits
1460                        .entry(start_region.buffer.remote_id())
1461                        .or_default()
1462                        .push(BufferEdit {
1463                            range: start_excerpt_range,
1464                            new_text: new_text.clone(),
1465                            is_insertion: true,
1466                            original_indent_column,
1467                            excerpt_id: start_region.excerpt.id,
1468                        });
1469                }
1470                if end_region.is_main_buffer {
1471                    edited_excerpt_ids.push(end_region.excerpt.id);
1472                    buffer_edits
1473                        .entry(end_region.buffer.remote_id())
1474                        .or_default()
1475                        .push(BufferEdit {
1476                            range: end_excerpt_range,
1477                            new_text: new_text.clone(),
1478                            is_insertion: false,
1479                            original_indent_column,
1480                            excerpt_id: end_region.excerpt.id,
1481                        });
1482                }
1483
1484                cursor.seek(&range.start);
1485                cursor.next_excerpt();
1486                while let Some(region) = cursor.region() {
1487                    if region.excerpt.id == end_region.excerpt.id {
1488                        break;
1489                    }
1490                    if region.is_main_buffer {
1491                        edited_excerpt_ids.push(region.excerpt.id);
1492                        buffer_edits
1493                            .entry(region.buffer.remote_id())
1494                            .or_default()
1495                            .push(BufferEdit {
1496                                range: region.buffer_range,
1497                                new_text: new_text.clone(),
1498                                is_insertion: false,
1499                                original_indent_column,
1500                                excerpt_id: region.excerpt.id,
1501                            });
1502                    }
1503                    cursor.next_excerpt();
1504                }
1505            }
1506        }
1507        (buffer_edits, edited_excerpt_ids)
1508    }
1509
1510    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1511    where
1512        I: IntoIterator<Item = Range<S>>,
1513        S: ToOffset,
1514    {
1515        if self.read_only() || self.buffers.is_empty() {
1516            return;
1517        }
1518        self.sync_mut(cx);
1519        let empty = Arc::<str>::from("");
1520        let edits = ranges
1521            .into_iter()
1522            .map(|range| {
1523                let mut range = range.start.to_offset(self.snapshot.get_mut())
1524                    ..range.end.to_offset(&self.snapshot.get_mut());
1525                if range.start > range.end {
1526                    mem::swap(&mut range.start, &mut range.end);
1527                }
1528                (range, empty.clone())
1529            })
1530            .collect::<Vec<_>>();
1531
1532        return autoindent_ranges_internal(self, edits, cx);
1533
1534        fn autoindent_ranges_internal(
1535            this: &mut MultiBuffer,
1536            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1537            cx: &mut Context<MultiBuffer>,
1538        ) {
1539            let (buffer_edits, edited_excerpt_ids) =
1540                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1541
1542            let mut buffer_ids = Vec::new();
1543            for (buffer_id, mut edits) in buffer_edits {
1544                buffer_ids.push(buffer_id);
1545                edits.sort_unstable_by_key(|edit| edit.range.start);
1546
1547                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1548                for edit in edits {
1549                    if let Some(last_range) = ranges.last_mut()
1550                        && edit.range.start <= last_range.end
1551                    {
1552                        last_range.end = last_range.end.max(edit.range.end);
1553                        continue;
1554                    }
1555                    ranges.push(edit.range);
1556                }
1557
1558                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1559                    buffer.autoindent_ranges(ranges, cx);
1560                })
1561            }
1562
1563            cx.emit(Event::ExcerptsEdited {
1564                excerpt_ids: edited_excerpt_ids,
1565                buffer_ids,
1566            });
1567        }
1568    }
1569
1570    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1571    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1572    /// Panics if the given position is invalid.
1573    pub fn insert_empty_line(
1574        &mut self,
1575        position: impl ToPoint,
1576        space_above: bool,
1577        space_below: bool,
1578        cx: &mut Context<Self>,
1579    ) -> Point {
1580        let multibuffer_point = position.to_point(&self.read(cx));
1581        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1582        self.start_transaction(cx);
1583        let empty_line_start = buffer.update(cx, |buffer, cx| {
1584            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1585        });
1586        self.end_transaction(cx);
1587        multibuffer_point + (empty_line_start - buffer_point)
1588    }
1589
1590    pub fn set_active_selections(
1591        &self,
1592        selections: &[Selection<Anchor>],
1593        line_mode: bool,
1594        cursor_shape: CursorShape,
1595        cx: &mut Context<Self>,
1596    ) {
1597        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1598            Default::default();
1599        let snapshot = self.read(cx);
1600        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1601        for selection in selections {
1602            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1603            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1604
1605            cursor.seek(&Some(start_locator), Bias::Left);
1606            while let Some(excerpt) = cursor.item()
1607                && excerpt.locator <= *end_locator
1608            {
1609                let mut start = excerpt.range.context.start;
1610                let mut end = excerpt.range.context.end;
1611                if excerpt.id == selection.start.excerpt_id {
1612                    start = selection.start.text_anchor;
1613                }
1614                if excerpt.id == selection.end.excerpt_id {
1615                    end = selection.end.text_anchor;
1616                }
1617                selections_by_buffer
1618                    .entry(excerpt.buffer_id)
1619                    .or_default()
1620                    .push(Selection {
1621                        id: selection.id,
1622                        start,
1623                        end,
1624                        reversed: selection.reversed,
1625                        goal: selection.goal,
1626                    });
1627
1628                cursor.next();
1629            }
1630        }
1631
1632        for (buffer_id, buffer_state) in self.buffers.iter() {
1633            if !selections_by_buffer.contains_key(buffer_id) {
1634                buffer_state
1635                    .buffer
1636                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1637            }
1638        }
1639
1640        for (buffer_id, mut selections) in selections_by_buffer {
1641            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1642                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1643                let mut selections = selections.into_iter().peekable();
1644                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1645                    let mut selection = selections.next()?;
1646                    while let Some(next_selection) = selections.peek() {
1647                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1648                            let next_selection = selections.next().unwrap();
1649                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1650                                selection.end = next_selection.end;
1651                            }
1652                        } else {
1653                            break;
1654                        }
1655                    }
1656                    Some(selection)
1657                }));
1658                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1659            });
1660        }
1661    }
1662
1663    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1664        for buffer in self.buffers.values() {
1665            buffer
1666                .buffer
1667                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1668        }
1669    }
1670
1671    pub fn push_excerpts<O>(
1672        &mut self,
1673        buffer: Entity<Buffer>,
1674        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1675        cx: &mut Context<Self>,
1676    ) -> Vec<ExcerptId>
1677    where
1678        O: text::ToOffset,
1679    {
1680        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1681    }
1682
1683    fn merge_excerpt_ranges<'a>(
1684        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1685    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1686        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1687        let mut counts: Vec<usize> = Vec::new();
1688        for range in expanded_ranges {
1689            if let Some(last_range) = merged_ranges.last_mut() {
1690                assert!(
1691                    last_range.context.start <= range.context.start,
1692                    "ranges must be sorted: {last_range:?} <= {range:?}"
1693                );
1694                if last_range.context.end >= range.context.start
1695                    || last_range.context.end.row + 1 == range.context.start.row
1696                {
1697                    last_range.context.end = range.context.end.max(last_range.context.end);
1698                    *counts.last_mut().unwrap() += 1;
1699                    continue;
1700                }
1701            }
1702            merged_ranges.push(range.clone());
1703            counts.push(1);
1704        }
1705        (merged_ranges, counts)
1706    }
1707
1708    pub fn insert_excerpts_after<O>(
1709        &mut self,
1710        prev_excerpt_id: ExcerptId,
1711        buffer: Entity<Buffer>,
1712        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1713        cx: &mut Context<Self>,
1714    ) -> Vec<ExcerptId>
1715    where
1716        O: text::ToOffset,
1717    {
1718        let mut ids = Vec::new();
1719        let mut next_excerpt_id =
1720            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1721                last_entry.id.0 + 1
1722            } else {
1723                1
1724            };
1725        self.insert_excerpts_with_ids_after(
1726            prev_excerpt_id,
1727            buffer,
1728            ranges.into_iter().map(|range| {
1729                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1730                ids.push(id);
1731                (id, range)
1732            }),
1733            cx,
1734        );
1735        ids
1736    }
1737
1738    pub fn insert_excerpts_with_ids_after<O>(
1739        &mut self,
1740        prev_excerpt_id: ExcerptId,
1741        buffer: Entity<Buffer>,
1742        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1743        cx: &mut Context<Self>,
1744    ) where
1745        O: text::ToOffset,
1746    {
1747        assert_eq!(self.history.transaction_depth(), 0);
1748        let mut ranges = ranges.into_iter().peekable();
1749        if ranges.peek().is_none() {
1750            return Default::default();
1751        }
1752
1753        self.sync_mut(cx);
1754
1755        let buffer_snapshot = buffer.read(cx).snapshot();
1756        let buffer_id = buffer_snapshot.remote_id();
1757
1758        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1759            self.buffer_changed_since_sync.replace(true);
1760            buffer.update(cx, |buffer, _| {
1761                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1762            });
1763            BufferState {
1764                last_version: RefCell::new(buffer_snapshot.version().clone()),
1765                last_non_text_state_update_count: Cell::new(
1766                    buffer_snapshot.non_text_state_update_count(),
1767                ),
1768                excerpts: Default::default(),
1769                _subscriptions: [
1770                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1771                    cx.subscribe(&buffer, Self::on_buffer_event),
1772                ],
1773                buffer: buffer.clone(),
1774            }
1775        });
1776
1777        let mut snapshot = self.snapshot.get_mut();
1778
1779        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1780        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1781        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1782        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1783        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1784
1785        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1786        new_excerpts.update_last(
1787            |excerpt| {
1788                excerpt.has_trailing_newline = true;
1789            },
1790            (),
1791        );
1792
1793        let next_locator = if let Some(excerpt) = cursor.item() {
1794            excerpt.locator.clone()
1795        } else {
1796            Locator::max()
1797        };
1798
1799        let mut excerpts = Vec::new();
1800        while let Some((id, range)) = ranges.next() {
1801            let locator = Locator::between(&prev_locator, &next_locator);
1802            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1803                buffer_state.excerpts.insert(ix, locator.clone());
1804            }
1805            let range = ExcerptRange {
1806                context: buffer_snapshot.anchor_before(&range.context.start)
1807                    ..buffer_snapshot.anchor_after(&range.context.end),
1808                primary: buffer_snapshot.anchor_before(&range.primary.start)
1809                    ..buffer_snapshot.anchor_after(&range.primary.end),
1810            };
1811            excerpts.push((id, range.clone()));
1812            let excerpt = Excerpt::new(
1813                id,
1814                locator.clone(),
1815                buffer_id,
1816                buffer_snapshot.clone(),
1817                range,
1818                ranges.peek().is_some() || cursor.item().is_some(),
1819            );
1820            new_excerpts.push(excerpt, ());
1821            prev_locator = locator.clone();
1822
1823            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1824                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1825            }
1826            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1827        }
1828
1829        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1830
1831        let suffix = cursor.suffix();
1832        let changed_trailing_excerpt = suffix.is_empty();
1833        new_excerpts.append(suffix, ());
1834        drop(cursor);
1835        snapshot.excerpts = new_excerpts;
1836        snapshot.excerpt_ids = new_excerpt_ids;
1837        if changed_trailing_excerpt {
1838            snapshot.trailing_excerpt_update_count += 1;
1839        }
1840
1841        let edits = Self::sync_diff_transforms(
1842            &mut snapshot,
1843            vec![Edit {
1844                old: edit_start..edit_start,
1845                new: edit_start..edit_end,
1846            }],
1847            DiffChangeKind::BufferEdited,
1848        );
1849        if !edits.is_empty() {
1850            self.subscriptions.publish(edits);
1851        }
1852
1853        cx.emit(Event::Edited {
1854            edited_buffer: None,
1855        });
1856        cx.emit(Event::ExcerptsAdded {
1857            buffer,
1858            predecessor: prev_excerpt_id,
1859            excerpts,
1860        });
1861        cx.notify();
1862    }
1863
1864    pub fn clear(&mut self, cx: &mut Context<Self>) {
1865        self.sync_mut(cx);
1866        let ids = self.excerpt_ids();
1867        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1868        self.excerpts_by_path.clear();
1869        self.paths_by_excerpt.clear();
1870        let MultiBufferSnapshot {
1871            excerpts,
1872            diffs: _,
1873            diff_transforms: _,
1874            non_text_state_update_count: _,
1875            edit_count: _,
1876            is_dirty,
1877            has_deleted_file,
1878            has_conflict,
1879            singleton: _,
1880            excerpt_ids: _,
1881            replaced_excerpts,
1882            trailing_excerpt_update_count,
1883            all_diff_hunks_expanded: _,
1884            show_deleted_hunks: _,
1885            show_headers: _,
1886        } = self.snapshot.get_mut();
1887        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1888        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1889        *excerpts = Default::default();
1890        *trailing_excerpt_update_count += 1;
1891        *is_dirty = false;
1892        *has_deleted_file = false;
1893        *has_conflict = false;
1894        replaced_excerpts.clear();
1895
1896        let edits = Self::sync_diff_transforms(
1897            self.snapshot.get_mut(),
1898            vec![Edit {
1899                old: start..prev_len,
1900                new: start..start,
1901            }],
1902            DiffChangeKind::BufferEdited,
1903        );
1904        if !edits.is_empty() {
1905            self.subscriptions.publish(edits);
1906        }
1907        cx.emit(Event::Edited {
1908            edited_buffer: None,
1909        });
1910        cx.emit(Event::ExcerptsRemoved {
1911            ids,
1912            removed_buffer_ids,
1913        });
1914        cx.notify();
1915    }
1916
1917    pub fn excerpts_for_buffer(
1918        &self,
1919        buffer_id: BufferId,
1920        cx: &App,
1921    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1922        let mut excerpts = Vec::new();
1923        let snapshot = self.read(cx);
1924        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1925        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1926            for locator in locators {
1927                cursor.seek_forward(&Some(locator), Bias::Left);
1928                if let Some(excerpt) = cursor.item()
1929                    && excerpt.locator == *locator
1930                {
1931                    excerpts.push((excerpt.id, excerpt.range.clone()));
1932                }
1933            }
1934        }
1935
1936        excerpts
1937    }
1938
1939    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1940        let snapshot = self.read(cx);
1941        let mut excerpts = snapshot
1942            .excerpts
1943            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
1944        let mut diff_transforms = snapshot
1945            .diff_transforms
1946            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1947        diff_transforms.next();
1948        let locators = self
1949            .buffers
1950            .get(&buffer_id)
1951            .into_iter()
1952            .flat_map(|state| &state.excerpts);
1953        let mut result = Vec::new();
1954        for locator in locators {
1955            excerpts.seek_forward(&Some(locator), Bias::Left);
1956            if let Some(excerpt) = excerpts.item()
1957                && excerpt.locator == *locator
1958            {
1959                let excerpt_start = excerpts.start().1;
1960                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1961
1962                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1963                let overshoot = excerpt_start - diff_transforms.start().0;
1964                let start = diff_transforms.start().1 + overshoot;
1965
1966                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1967                let overshoot = excerpt_end - diff_transforms.start().0;
1968                let end = diff_transforms.start().1 + overshoot;
1969
1970                result.push(start.0..end.0)
1971            }
1972        }
1973        result
1974    }
1975
1976    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1977        self.snapshot
1978            .borrow()
1979            .excerpts
1980            .iter()
1981            .map(|entry| entry.buffer_id)
1982            .collect()
1983    }
1984
1985    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1986        self.snapshot
1987            .borrow()
1988            .excerpts
1989            .iter()
1990            .map(|entry| entry.id)
1991            .collect()
1992    }
1993
1994    pub fn excerpt_containing(
1995        &self,
1996        position: impl ToOffset,
1997        cx: &App,
1998    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1999        let snapshot = self.read(cx);
2000        let offset = position.to_offset(&snapshot);
2001
2002        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2003        cursor.seek(&offset);
2004        cursor
2005            .excerpt()
2006            .or_else(|| snapshot.excerpts.last())
2007            .map(|excerpt| {
2008                (
2009                    excerpt.id,
2010                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2011                    excerpt.range.context.clone(),
2012                )
2013            })
2014    }
2015
2016    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2017        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2018            self.buffer(buffer_id)
2019        } else {
2020            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2021            Some(buffer)
2022        }
2023    }
2024
2025    // If point is at the end of the buffer, the last excerpt is returned
2026    pub fn point_to_buffer_offset<T: ToOffset>(
2027        &self,
2028        point: T,
2029        cx: &App,
2030    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2031        let snapshot = self.read(cx);
2032        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2033        Some((
2034            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2035            offset,
2036        ))
2037    }
2038
2039    // If point is at the end of the buffer, the last excerpt is returned
2040    pub fn point_to_buffer_point<T: ToPoint>(
2041        &self,
2042        point: T,
2043        cx: &App,
2044    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2045        let snapshot = self.read(cx);
2046        let (buffer, point, is_main_buffer) =
2047            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2048        Some((
2049            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2050            point,
2051            is_main_buffer,
2052        ))
2053    }
2054
2055    pub fn buffer_point_to_anchor(
2056        &self,
2057        buffer: &Entity<Buffer>,
2058        point: Point,
2059        cx: &App,
2060    ) -> Option<Anchor> {
2061        let mut found = None;
2062        let snapshot = buffer.read(cx).snapshot();
2063        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2064            let start = range.context.start.to_point(&snapshot);
2065            let end = range.context.end.to_point(&snapshot);
2066            if start <= point && point < end {
2067                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2068                break;
2069            }
2070            if point < start {
2071                found = Some((start, excerpt_id));
2072            }
2073            if point > end {
2074                found = Some((end, excerpt_id));
2075            }
2076        }
2077
2078        found.map(|(point, excerpt_id)| {
2079            let text_anchor = snapshot.anchor_after(point);
2080            Anchor::in_buffer(excerpt_id, text_anchor)
2081        })
2082    }
2083
2084    pub fn buffer_anchor_to_anchor(
2085        &self,
2086        buffer: &Entity<Buffer>,
2087        anchor: text::Anchor,
2088        cx: &App,
2089    ) -> Option<Anchor> {
2090        let snapshot = buffer.read(cx).snapshot();
2091        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2092            if range.context.start.cmp(&anchor, &snapshot).is_le()
2093                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2094            {
2095                return Some(Anchor::in_buffer(excerpt_id, anchor));
2096            }
2097        }
2098
2099        None
2100    }
2101
2102    pub fn remove_excerpts(
2103        &mut self,
2104        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2105        cx: &mut Context<Self>,
2106    ) {
2107        self.sync_mut(cx);
2108        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2109        if ids.is_empty() {
2110            return;
2111        }
2112        self.buffer_changed_since_sync.replace(true);
2113
2114        let mut snapshot = self.snapshot.get_mut();
2115        let mut new_excerpts = SumTree::default();
2116        let mut cursor = snapshot
2117            .excerpts
2118            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2119        let mut edits = Vec::new();
2120        let mut excerpt_ids = ids.iter().copied().peekable();
2121        let mut removed_buffer_ids = Vec::new();
2122
2123        while let Some(excerpt_id) = excerpt_ids.next() {
2124            self.paths_by_excerpt.remove(&excerpt_id);
2125            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2126            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2127            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2128
2129            if let Some(mut excerpt) = cursor.item() {
2130                if excerpt.id != excerpt_id {
2131                    continue;
2132                }
2133                let mut old_start = cursor.start().1;
2134
2135                // Skip over the removed excerpt.
2136                'remove_excerpts: loop {
2137                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2138                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2139                        if buffer_state.excerpts.is_empty() {
2140                            log::debug!(
2141                                "removing buffer and diff for buffer {}",
2142                                excerpt.buffer_id
2143                            );
2144                            self.buffers.remove(&excerpt.buffer_id);
2145                            removed_buffer_ids.push(excerpt.buffer_id);
2146                        }
2147                    }
2148                    cursor.next();
2149
2150                    // Skip over any subsequent excerpts that are also removed.
2151                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2152                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2153                        if let Some(next_excerpt) = cursor.item()
2154                            && next_excerpt.locator == *next_locator
2155                        {
2156                            excerpt_ids.next();
2157                            excerpt = next_excerpt;
2158                            continue 'remove_excerpts;
2159                        }
2160                    }
2161
2162                    break;
2163                }
2164
2165                // When removing the last excerpt, remove the trailing newline from
2166                // the previous excerpt.
2167                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2168                    old_start -= 1;
2169                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2170                }
2171
2172                // Push an edit for the removal of this run of excerpts.
2173                let old_end = cursor.start().1;
2174                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2175                edits.push(Edit {
2176                    old: old_start..old_end,
2177                    new: new_start..new_start,
2178                });
2179            }
2180        }
2181        let suffix = cursor.suffix();
2182        let changed_trailing_excerpt = suffix.is_empty();
2183        new_excerpts.append(suffix, ());
2184        drop(cursor);
2185        snapshot.excerpts = new_excerpts;
2186        for buffer_id in &removed_buffer_ids {
2187            self.diffs.remove(buffer_id);
2188            snapshot.diffs.remove(buffer_id);
2189        }
2190
2191        if changed_trailing_excerpt {
2192            snapshot.trailing_excerpt_update_count += 1;
2193        }
2194
2195        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2196        if !edits.is_empty() {
2197            self.subscriptions.publish(edits);
2198        }
2199        cx.emit(Event::Edited {
2200            edited_buffer: None,
2201        });
2202        cx.emit(Event::ExcerptsRemoved {
2203            ids,
2204            removed_buffer_ids,
2205        });
2206        cx.notify();
2207    }
2208
2209    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2210        &self,
2211        anchors: Anchors,
2212        cx: &mut Context<Self>,
2213    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2214        let mut error = None;
2215        let mut futures = Vec::new();
2216        for anchor in anchors {
2217            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2218                if let Some(buffer) = self.buffers.get(&buffer_id) {
2219                    buffer.buffer.update(cx, |buffer, _| {
2220                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2221                    });
2222                } else {
2223                    error = Some(anyhow!(
2224                        "buffer {buffer_id} is not part of this multi-buffer"
2225                    ));
2226                    break;
2227                }
2228            }
2229        }
2230        async move {
2231            if let Some(error) = error {
2232                Err(error)?;
2233            }
2234            for future in futures {
2235                future.await?;
2236            }
2237            Ok(())
2238        }
2239    }
2240
2241    pub fn text_anchor_for_position<T: ToOffset>(
2242        &self,
2243        position: T,
2244        cx: &App,
2245    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2246        let snapshot = self.read(cx);
2247        let anchor = snapshot.anchor_before(position);
2248        let buffer = self
2249            .buffers
2250            .get(&anchor.text_anchor.buffer_id?)?
2251            .buffer
2252            .clone();
2253        Some((buffer, anchor.text_anchor))
2254    }
2255
2256    fn on_buffer_event(
2257        &mut self,
2258        buffer: Entity<Buffer>,
2259        event: &language::BufferEvent,
2260        cx: &mut Context<Self>,
2261    ) {
2262        use language::BufferEvent;
2263        cx.emit(match event {
2264            BufferEvent::Edited => Event::Edited {
2265                edited_buffer: Some(buffer),
2266            },
2267            BufferEvent::DirtyChanged => Event::DirtyChanged,
2268            BufferEvent::Saved => Event::Saved,
2269            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2270            BufferEvent::Reloaded => Event::Reloaded,
2271            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2272            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2273            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2274            BufferEvent::CapabilityChanged => {
2275                self.capability = buffer.read(cx).capability();
2276                return;
2277            }
2278            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2279        });
2280    }
2281
2282    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2283        let diff = diff.read(cx);
2284        let buffer_id = diff.buffer_id;
2285        let diff = DiffStateSnapshot {
2286            diff: diff.snapshot(cx),
2287            main_buffer: None,
2288        };
2289        dbg!();
2290        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2291    }
2292
2293    fn inverted_buffer_diff_language_changed(
2294        &mut self,
2295        base_text_buffer_id: BufferId,
2296        diff: Entity<BufferDiff>,
2297        main_buffer: WeakEntity<Buffer>,
2298        cx: &mut Context<Self>,
2299    ) {
2300        let diff = diff.read(cx);
2301        let diff = DiffStateSnapshot {
2302            diff: diff.snapshot(cx),
2303            main_buffer: main_buffer
2304                .update(cx, |main_buffer, _| main_buffer.snapshot())
2305                .ok(),
2306        };
2307        self.snapshot
2308            .get_mut()
2309            .diffs
2310            .insert(base_text_buffer_id, diff);
2311    }
2312
2313    fn buffer_diff_changed(
2314        &mut self,
2315        diff: Entity<BufferDiff>,
2316        range: Range<text::Anchor>,
2317        cx: &mut Context<Self>,
2318    ) {
2319        self.sync_mut(cx);
2320
2321        let diff = diff.read(cx);
2322        let buffer_id = diff.buffer_id;
2323
2324        let new_diff = DiffStateSnapshot {
2325            diff: diff.snapshot(cx),
2326            main_buffer: None,
2327        };
2328        let mut snapshot = self.snapshot.get_mut();
2329        let base_text_changed = snapshot
2330            .diffs
2331            .get(&buffer_id)
2332            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2333        snapshot.diffs.insert_or_replace(dbg!(buffer_id), new_diff);
2334
2335        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2336            return;
2337        };
2338        self.buffer_changed_since_sync.replace(true);
2339
2340        let buffer = buffer_state.buffer.read(cx);
2341        let diff_change_range = range.to_offset(buffer);
2342
2343        let mut excerpt_edits = Vec::new();
2344        for locator in &buffer_state.excerpts {
2345            let mut cursor = snapshot
2346                .excerpts
2347                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2348            cursor.seek_forward(&Some(locator), Bias::Left);
2349            if let Some(excerpt) = cursor.item()
2350                && excerpt.locator == *locator
2351            {
2352                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2353                if diff_change_range.end < excerpt_buffer_range.start
2354                    || diff_change_range.start > excerpt_buffer_range.end
2355                {
2356                    continue;
2357                }
2358                let excerpt_start = cursor.start().1;
2359                let excerpt_len = excerpt.text_summary.len;
2360                let diff_change_start_in_excerpt = diff_change_range
2361                    .start
2362                    .saturating_sub(excerpt_buffer_range.start);
2363                let diff_change_end_in_excerpt = diff_change_range
2364                    .end
2365                    .saturating_sub(excerpt_buffer_range.start);
2366                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2367                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2368                excerpt_edits.push(Edit {
2369                    old: edit_start..edit_end,
2370                    new: edit_start..edit_end,
2371                });
2372            }
2373        }
2374
2375        let edits = Self::sync_diff_transforms(
2376            &mut snapshot,
2377            excerpt_edits,
2378            DiffChangeKind::DiffUpdated {
2379                base_changed: base_text_changed,
2380            },
2381        );
2382        if !edits.is_empty() {
2383            self.subscriptions.publish(edits);
2384        }
2385        cx.emit(Event::Edited {
2386            edited_buffer: None,
2387        });
2388    }
2389
2390    fn inverted_buffer_diff_changed(
2391        &mut self,
2392        diff: Entity<BufferDiff>,
2393        diff_change_range: Range<usize>,
2394        base_text_buffer_id: BufferId,
2395        main_buffer: WeakEntity<Buffer>,
2396        cx: &mut Context<Self>,
2397    ) {
2398        self.sync_mut(cx);
2399
2400        let diff = diff.read(cx);
2401        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2402            return;
2403        };
2404        self.buffer_changed_since_sync.replace(true);
2405
2406        let new_diff = DiffStateSnapshot {
2407            diff: diff.snapshot(cx),
2408            main_buffer: main_buffer
2409                .update(cx, |main_buffer, _| main_buffer.snapshot())
2410                .ok(),
2411        };
2412        let mut snapshot = self.snapshot.get_mut();
2413        let base_text_changed = snapshot
2414            .diffs
2415            .get(&base_text_buffer_id)
2416            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2417
2418        snapshot
2419            .diffs
2420            .insert_or_replace(base_text_buffer_id, new_diff);
2421
2422        let mut excerpt_edits = Vec::new();
2423        for locator in &buffer_state.excerpts {
2424            let mut cursor = snapshot
2425                .excerpts
2426                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2427            cursor.seek_forward(&Some(locator), Bias::Left);
2428            if let Some(excerpt) = cursor.item()
2429                && excerpt.locator == *locator
2430            {
2431                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2432                if diff_change_range.end < excerpt_buffer_range.start
2433                    || diff_change_range.start > excerpt_buffer_range.end
2434                {
2435                    continue;
2436                }
2437                let excerpt_start = cursor.start().1;
2438                let excerpt_len = excerpt.text_summary.len;
2439                let diff_change_start_in_excerpt = diff_change_range
2440                    .start
2441                    .saturating_sub(excerpt_buffer_range.start);
2442                let diff_change_end_in_excerpt = diff_change_range
2443                    .end
2444                    .saturating_sub(excerpt_buffer_range.start);
2445                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2446                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2447                excerpt_edits.push(Edit {
2448                    old: edit_start..edit_end,
2449                    new: edit_start..edit_end,
2450                });
2451            }
2452        }
2453
2454        let edits = Self::sync_diff_transforms(
2455            &mut snapshot,
2456            excerpt_edits,
2457            DiffChangeKind::DiffUpdated {
2458                base_changed: base_text_changed,
2459            },
2460        );
2461        if !edits.is_empty() {
2462            self.subscriptions.publish(edits);
2463        }
2464        cx.emit(Event::Edited {
2465            edited_buffer: None,
2466        });
2467    }
2468
2469    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2470        self.buffers.values().map(|state| state.buffer.clone())
2471    }
2472
2473    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2474        self.all_buffers_iter().collect()
2475    }
2476
2477    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2478        self.buffers.keys().copied()
2479    }
2480
2481    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2482        self.all_buffer_ids_iter().collect()
2483    }
2484
2485    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2486        self.buffers
2487            .get(&buffer_id)
2488            .map(|state| state.buffer.clone())
2489    }
2490
2491    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2492        self.point_to_buffer_offset(point, cx)
2493            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2494    }
2495
2496    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2497        let buffer_id = self
2498            .snapshot
2499            .borrow()
2500            .excerpts
2501            .first()
2502            .map(|excerpt| excerpt.buffer.remote_id());
2503        buffer_id
2504            .and_then(|buffer_id| self.buffer(buffer_id))
2505            .map(|buffer| {
2506                let buffer = buffer.read(cx);
2507                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2508            })
2509            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2510    }
2511
2512    pub fn language_settings_at<'a, T: ToOffset>(
2513        &'a self,
2514        point: T,
2515        cx: &'a App,
2516    ) -> Cow<'a, LanguageSettings> {
2517        let mut language = None;
2518        let mut file = None;
2519        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2520            let buffer = buffer.read(cx);
2521            language = buffer.language_at(offset);
2522            file = buffer.file();
2523        }
2524        language_settings(language.map(|l| l.name()), file, cx)
2525    }
2526
2527    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2528        self.buffers.values().for_each(|state| f(&state.buffer))
2529    }
2530
2531    pub fn explicit_title(&self) -> Option<&str> {
2532        self.title.as_deref()
2533    }
2534
2535    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2536        if let Some(title) = self.title.as_ref() {
2537            return title.into();
2538        }
2539
2540        if let Some(buffer) = self.as_singleton() {
2541            let buffer = buffer.read(cx);
2542
2543            if let Some(file) = buffer.file() {
2544                return file.file_name(cx).into();
2545            }
2546
2547            if let Some(title) = self.buffer_content_title(buffer) {
2548                return title;
2549            }
2550        };
2551
2552        "untitled".into()
2553    }
2554
2555    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2556        let mut is_leading_whitespace = true;
2557        let mut count = 0;
2558        let mut prev_was_space = false;
2559        let mut title = String::new();
2560
2561        for ch in buffer.snapshot().chars() {
2562            if is_leading_whitespace && ch.is_whitespace() {
2563                continue;
2564            }
2565
2566            is_leading_whitespace = false;
2567
2568            if ch == '\n' || count >= 40 {
2569                break;
2570            }
2571
2572            if ch.is_whitespace() {
2573                if !prev_was_space {
2574                    title.push(' ');
2575                    count += 1;
2576                    prev_was_space = true;
2577                }
2578            } else {
2579                title.push(ch);
2580                count += 1;
2581                prev_was_space = false;
2582            }
2583        }
2584
2585        let title = title.trim_end().to_string();
2586
2587        if title.is_empty() {
2588            return None;
2589        }
2590
2591        Some(title.into())
2592    }
2593
2594    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2595        self.title = Some(title);
2596        cx.notify();
2597    }
2598
2599    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2600    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2601        for buffer_state in self.buffers.values() {
2602            buffer_state
2603                .buffer
2604                .update(cx, |buffer, _cx| buffer.refresh_preview());
2605        }
2606    }
2607
2608    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2609    pub fn preserve_preview(&self, cx: &App) -> bool {
2610        self.buffers
2611            .values()
2612            .all(|state| state.buffer.read(cx).preserve_preview())
2613    }
2614
2615    #[cfg(any(test, feature = "test-support"))]
2616    pub fn is_parsing(&self, cx: &App) -> bool {
2617        self.as_singleton().unwrap().read(cx).is_parsing()
2618    }
2619
2620    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2621        debug_assert!(self.diffs.values().all(|diff| diff.main_buffer.is_none()));
2622
2623        let buffer_id = diff.read(cx).buffer_id;
2624        self.buffer_diff_changed(
2625            diff.clone(),
2626            text::Anchor::min_max_range_for_buffer(buffer_id),
2627            cx,
2628        );
2629        self.diffs
2630            .insert(buffer_id, DiffState::new(diff.clone(), cx));
2631    }
2632
2633    pub fn add_inverted_diff(
2634        &mut self,
2635        base_text_buffer_id: BufferId,
2636        diff: Entity<BufferDiff>,
2637        main_buffer: Entity<Buffer>,
2638        cx: &mut Context<Self>,
2639    ) {
2640        debug_assert!(self.diffs.values().all(|diff| diff.main_buffer.is_some()));
2641
2642        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2643        self.inverted_buffer_diff_changed(
2644            diff.clone(),
2645            diff_change_range,
2646            base_text_buffer_id,
2647            main_buffer.downgrade(),
2648            cx,
2649        );
2650        self.diffs.insert(
2651            base_text_buffer_id,
2652            DiffState::new_inverted(diff, base_text_buffer_id, main_buffer, cx),
2653        );
2654    }
2655
2656    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2657        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2658    }
2659
2660    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2661        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2662    }
2663
2664    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2665        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2666    }
2667
2668    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2669        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2670        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2671    }
2672
2673    pub fn all_diff_hunks_expanded(&self) -> bool {
2674        self.snapshot.borrow().all_diff_hunks_expanded
2675    }
2676
2677    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2678        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2679        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2680    }
2681
2682    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2683        self.snapshot.get_mut().show_deleted_hunks = show;
2684        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2685    }
2686
2687    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2688        self.read(cx)
2689            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2690            .nth(1)
2691            .is_some()
2692    }
2693
2694    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2695        let snapshot = self.read(cx);
2696        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2697        let offset_range = range.to_offset(&snapshot);
2698        cursor.seek(&offset_range.start, Bias::Left);
2699        while let Some(item) = cursor.item() {
2700            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2701                break;
2702            }
2703            if item.hunk_info().is_some() {
2704                return true;
2705            }
2706            cursor.next();
2707        }
2708        false
2709    }
2710
2711    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2712        let snapshot = self.read(cx);
2713        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2714        for range in ranges {
2715            let range = range.to_point(&snapshot);
2716            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2717            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2718            let start = start.saturating_sub_usize(1);
2719            let end = snapshot.len().min(end + 1usize);
2720            cursor.seek(&start, Bias::Right);
2721            while let Some(item) = cursor.item() {
2722                if *cursor.start() >= end {
2723                    break;
2724                }
2725                if item.hunk_info().is_some() {
2726                    return true;
2727                }
2728                cursor.next();
2729            }
2730        }
2731        false
2732    }
2733
2734    pub fn expand_or_collapse_diff_hunks_inner(
2735        &mut self,
2736        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2737        expand: bool,
2738        cx: &mut Context<Self>,
2739    ) {
2740        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2741            return;
2742        }
2743        self.sync_mut(cx);
2744        let mut snapshot = self.snapshot.get_mut();
2745        let mut excerpt_edits = Vec::new();
2746        let mut last_hunk_row = None;
2747        for (range, end_excerpt_id) in ranges {
2748            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2749                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2750                    continue;
2751                }
2752                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2753                    continue;
2754                }
2755                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2756                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2757                let start = snapshot.excerpt_offset_for_anchor(&start);
2758                let end = snapshot.excerpt_offset_for_anchor(&end);
2759                last_hunk_row = Some(diff_hunk.row_range.start);
2760                excerpt_edits.push(text::Edit {
2761                    old: start..end,
2762                    new: start..end,
2763                });
2764            }
2765        }
2766
2767        let edits = Self::sync_diff_transforms(
2768            &mut snapshot,
2769            excerpt_edits,
2770            DiffChangeKind::ExpandOrCollapseHunks { expand },
2771        );
2772        if !edits.is_empty() {
2773            self.subscriptions.publish(edits);
2774        }
2775        cx.emit(Event::DiffHunksToggled);
2776        cx.emit(Event::Edited {
2777            edited_buffer: None,
2778        });
2779    }
2780
2781    pub fn expand_or_collapse_diff_hunks(
2782        &mut self,
2783        ranges: Vec<Range<Anchor>>,
2784        expand: bool,
2785        cx: &mut Context<Self>,
2786    ) {
2787        let snapshot = self.snapshot.borrow().clone();
2788        let ranges = ranges.iter().map(move |range| {
2789            let end_excerpt_id = range.end.excerpt_id;
2790            let range = range.to_point(&snapshot);
2791            let mut peek_end = range.end;
2792            if range.end.row < snapshot.max_row().0 {
2793                peek_end = Point::new(range.end.row + 1, 0);
2794            };
2795            (range.start..peek_end, end_excerpt_id)
2796        });
2797        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2798    }
2799
2800    pub fn resize_excerpt(
2801        &mut self,
2802        id: ExcerptId,
2803        range: Range<text::Anchor>,
2804        cx: &mut Context<Self>,
2805    ) {
2806        self.sync_mut(cx);
2807
2808        let mut snapshot = self.snapshot.get_mut();
2809        let locator = snapshot.excerpt_locator_for_id(id);
2810        let mut new_excerpts = SumTree::default();
2811        let mut cursor = snapshot
2812            .excerpts
2813            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2814        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2815
2816        let prefix = cursor.slice(&Some(locator), Bias::Left);
2817        new_excerpts.append(prefix, ());
2818
2819        let mut excerpt = cursor.item().unwrap().clone();
2820        let old_text_len = excerpt.text_summary.len;
2821
2822        excerpt.range.context.start = range.start;
2823        excerpt.range.context.end = range.end;
2824        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2825
2826        excerpt.text_summary = excerpt
2827            .buffer
2828            .text_summary_for_range(excerpt.range.context.clone());
2829
2830        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2831        let old_start_offset = cursor.start().1;
2832        let new_text_len = excerpt.text_summary.len;
2833        let edit = Edit {
2834            old: old_start_offset..old_start_offset + old_text_len,
2835            new: new_start_offset..new_start_offset + new_text_len,
2836        };
2837
2838        if let Some(last_edit) = edits.last_mut() {
2839            if last_edit.old.end == edit.old.start {
2840                last_edit.old.end = edit.old.end;
2841                last_edit.new.end = edit.new.end;
2842            } else {
2843                edits.push(edit);
2844            }
2845        } else {
2846            edits.push(edit);
2847        }
2848
2849        new_excerpts.push(excerpt, ());
2850
2851        cursor.next();
2852
2853        new_excerpts.append(cursor.suffix(), ());
2854
2855        drop(cursor);
2856        snapshot.excerpts = new_excerpts;
2857
2858        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2859        if !edits.is_empty() {
2860            self.subscriptions.publish(edits);
2861        }
2862        cx.emit(Event::Edited {
2863            edited_buffer: None,
2864        });
2865        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2866        cx.notify();
2867    }
2868
2869    pub fn expand_excerpts(
2870        &mut self,
2871        ids: impl IntoIterator<Item = ExcerptId>,
2872        line_count: u32,
2873        direction: ExpandExcerptDirection,
2874        cx: &mut Context<Self>,
2875    ) {
2876        if line_count == 0 {
2877            return;
2878        }
2879        self.sync_mut(cx);
2880        if !self.excerpts_by_path.is_empty() {
2881            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2882            return;
2883        }
2884        let mut snapshot = self.snapshot.get_mut();
2885
2886        let ids = ids.into_iter().collect::<Vec<_>>();
2887        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2888        let mut new_excerpts = SumTree::default();
2889        let mut cursor = snapshot
2890            .excerpts
2891            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2892        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2893
2894        for locator in &locators {
2895            let prefix = cursor.slice(&Some(locator), Bias::Left);
2896            new_excerpts.append(prefix, ());
2897
2898            let mut excerpt = cursor.item().unwrap().clone();
2899            let old_text_len = excerpt.text_summary.len;
2900
2901            let up_line_count = if direction.should_expand_up() {
2902                line_count
2903            } else {
2904                0
2905            };
2906
2907            let start_row = excerpt
2908                .range
2909                .context
2910                .start
2911                .to_point(&excerpt.buffer)
2912                .row
2913                .saturating_sub(up_line_count);
2914            let start_point = Point::new(start_row, 0);
2915            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2916
2917            let down_line_count = if direction.should_expand_down() {
2918                line_count
2919            } else {
2920                0
2921            };
2922
2923            let mut end_point = excerpt.buffer.clip_point(
2924                excerpt.range.context.end.to_point(&excerpt.buffer)
2925                    + Point::new(down_line_count, 0),
2926                Bias::Left,
2927            );
2928            end_point.column = excerpt.buffer.line_len(end_point.row);
2929            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2930            excerpt.max_buffer_row = end_point.row;
2931
2932            excerpt.text_summary = excerpt
2933                .buffer
2934                .text_summary_for_range(excerpt.range.context.clone());
2935
2936            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2937            let old_start_offset = cursor.start().1;
2938            let new_text_len = excerpt.text_summary.len;
2939            let edit = Edit {
2940                old: old_start_offset..old_start_offset + old_text_len,
2941                new: new_start_offset..new_start_offset + new_text_len,
2942            };
2943
2944            if let Some(last_edit) = edits.last_mut() {
2945                if last_edit.old.end == edit.old.start {
2946                    last_edit.old.end = edit.old.end;
2947                    last_edit.new.end = edit.new.end;
2948                } else {
2949                    edits.push(edit);
2950                }
2951            } else {
2952                edits.push(edit);
2953            }
2954
2955            new_excerpts.push(excerpt, ());
2956
2957            cursor.next();
2958        }
2959
2960        new_excerpts.append(cursor.suffix(), ());
2961
2962        drop(cursor);
2963        snapshot.excerpts = new_excerpts;
2964
2965        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2966        if !edits.is_empty() {
2967            self.subscriptions.publish(edits);
2968        }
2969        cx.emit(Event::Edited {
2970            edited_buffer: None,
2971        });
2972        cx.emit(Event::ExcerptsExpanded { ids });
2973        cx.notify();
2974    }
2975
2976    fn sync(&self, cx: &App) {
2977        let changed = self.buffer_changed_since_sync.replace(false);
2978        if !changed {
2979            return;
2980        }
2981        let edits = Self::sync_(
2982            &mut self.snapshot.borrow_mut(),
2983            &self.buffers,
2984            &self.diffs,
2985            cx,
2986        );
2987        if !edits.is_empty() {
2988            self.subscriptions.publish(edits);
2989        }
2990    }
2991
2992    fn sync_mut(&mut self, cx: &App) {
2993        let changed = self.buffer_changed_since_sync.replace(false);
2994        if !changed {
2995            return;
2996        }
2997        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2998
2999        if !edits.is_empty() {
3000            self.subscriptions.publish(edits);
3001        }
3002    }
3003
3004    fn sync_(
3005        snapshot: &mut MultiBufferSnapshot,
3006        buffers: &HashMap<BufferId, BufferState>,
3007        diffs: &HashMap<BufferId, DiffState>,
3008        cx: &App,
3009    ) -> Vec<Edit<MultiBufferOffset>> {
3010        let MultiBufferSnapshot {
3011            excerpts,
3012            diffs: buffer_diff,
3013            diff_transforms: _,
3014            non_text_state_update_count,
3015            edit_count,
3016            is_dirty,
3017            has_deleted_file,
3018            has_conflict,
3019            singleton: _,
3020            excerpt_ids: _,
3021            replaced_excerpts: _,
3022            trailing_excerpt_update_count: _,
3023            all_diff_hunks_expanded: _,
3024            show_deleted_hunks: _,
3025            show_headers: _,
3026        } = snapshot;
3027        *is_dirty = false;
3028        *has_deleted_file = false;
3029        *has_conflict = false;
3030
3031        let mut excerpts_to_edit = Vec::new();
3032        let mut non_text_state_updated = false;
3033        let mut edited = false;
3034        for buffer_state in buffers.values() {
3035            let buffer = buffer_state.buffer.read(cx);
3036            let version = buffer.version();
3037            let non_text_state_update_count = buffer.non_text_state_update_count();
3038
3039            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3040            let buffer_non_text_state_updated =
3041                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3042            if buffer_edited || buffer_non_text_state_updated {
3043                *buffer_state.last_version.borrow_mut() = version;
3044                buffer_state
3045                    .last_non_text_state_update_count
3046                    .set(non_text_state_update_count);
3047                excerpts_to_edit.extend(
3048                    buffer_state
3049                        .excerpts
3050                        .iter()
3051                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3052                );
3053            }
3054
3055            edited |= buffer_edited;
3056            non_text_state_updated |= buffer_non_text_state_updated;
3057            *is_dirty |= buffer.is_dirty();
3058            *has_deleted_file |= buffer
3059                .file()
3060                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3061            *has_conflict |= buffer.has_conflict();
3062        }
3063        if edited {
3064            *edit_count += 1;
3065        }
3066        if non_text_state_updated {
3067            *non_text_state_update_count += 1;
3068        }
3069
3070        for (id, diff) in diffs.iter() {
3071            if buffer_diff.get(id).is_none() {
3072                buffer_diff.insert(dbg!(*id), diff.snapshot(cx));
3073            }
3074        }
3075
3076        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3077
3078        let mut edits = Vec::new();
3079        let mut new_excerpts = SumTree::default();
3080        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3081
3082        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3083            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3084            let old_excerpt = cursor.item().unwrap();
3085            let buffer = buffer.read(cx);
3086            let buffer_id = buffer.remote_id();
3087
3088            let mut new_excerpt;
3089            if buffer_edited {
3090                edits.extend(
3091                    buffer
3092                        .edits_since_in_range::<usize>(
3093                            old_excerpt.buffer.version(),
3094                            old_excerpt.range.context.clone(),
3095                        )
3096                        .map(|edit| {
3097                            let excerpt_old_start = cursor.start().1;
3098                            let excerpt_new_start =
3099                                ExcerptDimension(new_excerpts.summary().text.len);
3100                            let old_start = excerpt_old_start + edit.old.start;
3101                            let old_end = excerpt_old_start + edit.old.end;
3102                            let new_start = excerpt_new_start + edit.new.start;
3103                            let new_end = excerpt_new_start + edit.new.end;
3104                            Edit {
3105                                old: old_start..old_end,
3106                                new: new_start..new_end,
3107                            }
3108                        }),
3109                );
3110
3111                new_excerpt = Excerpt::new(
3112                    old_excerpt.id,
3113                    locator.clone(),
3114                    buffer_id,
3115                    buffer.snapshot(),
3116                    old_excerpt.range.clone(),
3117                    old_excerpt.has_trailing_newline,
3118                );
3119            } else {
3120                new_excerpt = old_excerpt.clone();
3121                new_excerpt.buffer = buffer.snapshot();
3122            }
3123
3124            new_excerpts.push(new_excerpt, ());
3125            cursor.next();
3126        }
3127        new_excerpts.append(cursor.suffix(), ());
3128
3129        drop(cursor);
3130        *excerpts = new_excerpts;
3131        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3132    }
3133
3134    fn sync_diff_transforms(
3135        snapshot: &mut MultiBufferSnapshot,
3136        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3137        change_kind: DiffChangeKind,
3138    ) -> Vec<Edit<MultiBufferOffset>> {
3139        if excerpt_edits.is_empty() {
3140            return vec![];
3141        }
3142
3143        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3144        let mut old_diff_transforms = snapshot
3145            .diff_transforms
3146            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3147        let mut new_diff_transforms = SumTree::default();
3148        let mut old_expanded_hunks = HashSet::default();
3149        let mut output_edits = Vec::new();
3150        let mut output_delta = 0_isize;
3151        let mut at_transform_boundary = true;
3152        let mut end_of_current_insert = None;
3153
3154        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3155        while let Some(edit) = excerpt_edits.next() {
3156            excerpts.seek_forward(&edit.new.start, Bias::Right);
3157            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3158                excerpts.prev();
3159            }
3160
3161            // Keep any transforms that are before the edit.
3162            if at_transform_boundary {
3163                at_transform_boundary = false;
3164                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3165                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3166                if let Some(transform) = old_diff_transforms.item()
3167                    && old_diff_transforms.end().0 == edit.old.start
3168                    && old_diff_transforms.start().0 < edit.old.start
3169                {
3170                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3171                    old_diff_transforms.next();
3172                }
3173            }
3174
3175            // Compute the start of the edit in output coordinates.
3176            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3177            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3178            let edit_new_start =
3179                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3180
3181            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3182                &edit,
3183                &mut excerpts,
3184                &mut old_diff_transforms,
3185                &mut new_diff_transforms,
3186                &mut end_of_current_insert,
3187                &mut old_expanded_hunks,
3188                snapshot,
3189                change_kind,
3190            );
3191
3192            // Compute the end of the edit in output coordinates.
3193            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3194            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3195            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3196            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3197            let output_edit = Edit {
3198                old: edit_old_start..edit_old_end,
3199                new: edit_new_start..edit_new_end,
3200            };
3201
3202            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3203            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3204            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3205                output_edits.push(output_edit);
3206            }
3207
3208            // If this is the last edit that intersects the current diff transform,
3209            // then recreate the content up to the end of this transform, to prepare
3210            // for reusing additional slices of the old transforms.
3211            if excerpt_edits
3212                .peek()
3213                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3214            {
3215                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3216                    && match old_diff_transforms.item() {
3217                        Some(DiffTransform::BufferContent {
3218                            inserted_hunk_info: Some(hunk),
3219                            ..
3220                        }) => excerpts.item().is_some_and(|excerpt| {
3221                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3222                        }),
3223                        _ => true,
3224                    };
3225
3226                let mut excerpt_offset = edit.new.end;
3227                if !keep_next_old_transform {
3228                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3229                    old_diff_transforms.next();
3230                }
3231
3232                old_expanded_hunks.clear();
3233                Self::push_buffer_content_transform(
3234                    snapshot,
3235                    &mut new_diff_transforms,
3236                    excerpt_offset,
3237                    end_of_current_insert,
3238                );
3239                at_transform_boundary = true;
3240            }
3241        }
3242
3243        // Keep any transforms that are after the last edit.
3244        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3245
3246        // Ensure there's always at least one buffer content transform.
3247        if new_diff_transforms.is_empty() {
3248            new_diff_transforms.push(
3249                DiffTransform::BufferContent {
3250                    summary: Default::default(),
3251                    inserted_hunk_info: None,
3252                },
3253                (),
3254            );
3255        }
3256
3257        drop(old_diff_transforms);
3258        drop(excerpts);
3259        snapshot.diff_transforms = new_diff_transforms;
3260        snapshot.edit_count += 1;
3261
3262        #[cfg(any(test, feature = "test-support"))]
3263        snapshot.check_invariants();
3264        output_edits
3265    }
3266
3267    fn recompute_diff_transforms_for_edit(
3268        edit: &Edit<ExcerptOffset>,
3269        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3270        old_diff_transforms: &mut Cursor<
3271            DiffTransform,
3272            Dimensions<ExcerptOffset, MultiBufferOffset>,
3273        >,
3274        new_diff_transforms: &mut SumTree<DiffTransform>,
3275        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3276        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3277        snapshot: &MultiBufferSnapshot,
3278        change_kind: DiffChangeKind,
3279    ) -> bool {
3280        log::trace!(
3281            "recomputing diff transform for edit {:?} => {:?}",
3282            edit.old.start..edit.old.end,
3283            edit.new.start..edit.new.end
3284        );
3285
3286        dbg!(&change_kind);
3287
3288        // Record which hunks were previously expanded.
3289        while let Some(item) = old_diff_transforms.item() {
3290            if let Some(hunk_info) = item.hunk_info() {
3291                log::trace!(
3292                    "previously expanded hunk at {:?}",
3293                    old_diff_transforms.start()
3294                );
3295                old_expanded_hunks.insert(hunk_info);
3296            }
3297            if old_diff_transforms.end().0 > edit.old.end {
3298                break;
3299            }
3300            old_diff_transforms.next();
3301        }
3302
3303        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3304        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3305        if old_expanded_hunks.is_empty()
3306            && change_kind == DiffChangeKind::BufferEdited
3307            && !all_diff_hunks_expanded
3308        {
3309            return false;
3310        }
3311
3312        // Visit each excerpt that intersects the edit.
3313        let mut did_expand_hunks = false;
3314        while let Some(excerpt) = excerpts.item() {
3315            // Recompute the expanded hunks in the portion of the excerpt that
3316            // intersects the edit.
3317            if let Some(diff) = snapshot.diffs.get(dbg!(&excerpt.buffer_id)) {
3318                let buffer = &excerpt.buffer;
3319                let excerpt_start = *excerpts.start();
3320                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3321                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3322                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3323                let edit_buffer_start =
3324                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3325                let edit_buffer_end =
3326                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3327                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3328
3329                if let Some(main_buffer) = &diff.main_buffer {
3330                    for hunk in diff.hunks_intersecting_base_text_range(
3331                        edit_buffer_start..edit_buffer_end,
3332                        main_buffer,
3333                    ) {
3334                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3335                        if hunk_buffer_range.start < excerpt_buffer_start {
3336                            log::trace!("skipping hunk that starts before excerpt");
3337                            continue;
3338                        }
3339                        let hunk_excerpt_start = excerpt_start
3340                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3341                        let hunk_excerpt_end = excerpt_end
3342                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3343                        Self::push_buffer_content_transform(
3344                            snapshot,
3345                            new_diff_transforms,
3346                            hunk_excerpt_start,
3347                            *end_of_current_insert,
3348                        );
3349                        if !hunk_buffer_range.is_empty() {
3350                            let hunk_info = DiffTransformHunkInfo {
3351                                excerpt_id: excerpt.id,
3352                                hunk_start_anchor: hunk.buffer_range.start,
3353                                hunk_secondary_status: hunk.secondary_status,
3354                                is_logically_deleted: true,
3355                            };
3356                            *end_of_current_insert =
3357                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3358                        }
3359                    }
3360                } else {
3361                    dbg!(buffer.remote_id());
3362                    dbg!(diff.hunks(buffer).collect::<Vec<_>>());
3363
3364                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3365                        ..buffer.anchor_after(edit_buffer_end);
3366                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3367                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3368                            continue;
3369                        }
3370
3371                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3372                        if hunk_buffer_range.start < excerpt_buffer_start {
3373                            log::trace!("skipping hunk that starts before excerpt");
3374                            continue;
3375                        }
3376
3377                        let hunk_info = DiffTransformHunkInfo {
3378                            excerpt_id: excerpt.id,
3379                            hunk_start_anchor: hunk.buffer_range.start,
3380                            hunk_secondary_status: hunk.secondary_status,
3381                            is_logically_deleted: false,
3382                        };
3383
3384                        let hunk_excerpt_start = excerpt_start
3385                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3386                        let hunk_excerpt_end = excerpt_end
3387                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3388
3389                        Self::push_buffer_content_transform(
3390                            snapshot,
3391                            new_diff_transforms,
3392                            hunk_excerpt_start,
3393                            *end_of_current_insert,
3394                        );
3395
3396                        // For every existing hunk, determine if it was previously expanded
3397                        // and if it should currently be expanded.
3398                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3399                        let should_expand_hunk = match &change_kind {
3400                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3401                                was_previously_expanded || all_diff_hunks_expanded
3402                            }
3403                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3404                                let intersects = hunk_buffer_range.is_empty()
3405                                    || hunk_buffer_range.end > edit_buffer_start;
3406                                if *expand {
3407                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3408                                } else {
3409                                    !intersects
3410                                        && (was_previously_expanded || all_diff_hunks_expanded)
3411                                }
3412                            }
3413                            _ => was_previously_expanded || all_diff_hunks_expanded,
3414                        };
3415
3416                        if should_expand_hunk {
3417                            did_expand_hunks = true;
3418                            log::trace!(
3419                                "expanding hunk {:?}, excerpt:{:?}",
3420                                hunk_excerpt_start..hunk_excerpt_end,
3421                                excerpt.id
3422                            );
3423
3424                            dbg!(&hunk);
3425                            if !hunk.diff_base_byte_range.is_empty()
3426                                && hunk_buffer_range.start >= edit_buffer_start
3427                                && hunk_buffer_range.start <= excerpt_buffer_end
3428                                && dbg!(snapshot.show_deleted_hunks)
3429                            {
3430                                dbg!();
3431                                let base_text = diff.base_text();
3432                                let mut text_cursor =
3433                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3434                                let mut base_text_summary = text_cursor
3435                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3436
3437                                let mut has_trailing_newline = false;
3438                                if base_text_summary.last_line_chars > 0 {
3439                                    base_text_summary += TextSummary::newline();
3440                                    has_trailing_newline = true;
3441                                }
3442
3443                                new_diff_transforms.push(
3444                                    DiffTransform::DeletedHunk {
3445                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3446                                        summary: base_text_summary,
3447                                        buffer_id: excerpt.buffer_id,
3448                                        hunk_info,
3449                                        has_trailing_newline,
3450                                    },
3451                                    (),
3452                                );
3453                            }
3454
3455                            if !hunk_buffer_range.is_empty() {
3456                                *end_of_current_insert =
3457                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3458                            }
3459                        }
3460                    }
3461                }
3462            }
3463
3464            if excerpts.end() <= edit.new.end {
3465                excerpts.next();
3466            } else {
3467                break;
3468            }
3469        }
3470
3471        did_expand_hunks || !old_expanded_hunks.is_empty()
3472    }
3473
3474    fn append_diff_transforms(
3475        new_transforms: &mut SumTree<DiffTransform>,
3476        subtree: SumTree<DiffTransform>,
3477    ) {
3478        if let Some(DiffTransform::BufferContent {
3479            inserted_hunk_info,
3480            summary,
3481        }) = subtree.first()
3482            && Self::extend_last_buffer_content_transform(
3483                new_transforms,
3484                *inserted_hunk_info,
3485                *summary,
3486            )
3487        {
3488            let mut cursor = subtree.cursor::<()>(());
3489            cursor.next();
3490            cursor.next();
3491            new_transforms.append(cursor.suffix(), ());
3492            return;
3493        }
3494        new_transforms.append(subtree, ());
3495    }
3496
3497    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3498        if let DiffTransform::BufferContent {
3499            inserted_hunk_info: inserted_hunk_anchor,
3500            summary,
3501        } = transform
3502            && Self::extend_last_buffer_content_transform(
3503                new_transforms,
3504                inserted_hunk_anchor,
3505                summary,
3506            )
3507        {
3508            return;
3509        }
3510        new_transforms.push(transform, ());
3511    }
3512
3513    fn push_buffer_content_transform(
3514        old_snapshot: &MultiBufferSnapshot,
3515        new_transforms: &mut SumTree<DiffTransform>,
3516        end_offset: ExcerptOffset,
3517        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3518    ) {
3519        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3520            (end_offset.min(insertion_end_offset), Some(hunk_info))
3521        });
3522        let unchanged_region = [(end_offset, None)];
3523
3524        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3525        {
3526            let start_offset = new_transforms.summary().excerpt_len();
3527            if end_offset <= start_offset {
3528                continue;
3529            }
3530            let summary_to_add = old_snapshot
3531                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3532
3533            if !Self::extend_last_buffer_content_transform(
3534                new_transforms,
3535                inserted_hunk_info,
3536                summary_to_add,
3537            ) {
3538                new_transforms.push(
3539                    DiffTransform::BufferContent {
3540                        summary: summary_to_add,
3541                        inserted_hunk_info,
3542                    },
3543                    (),
3544                )
3545            }
3546        }
3547    }
3548
3549    fn extend_last_buffer_content_transform(
3550        new_transforms: &mut SumTree<DiffTransform>,
3551        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3552        summary_to_add: MBTextSummary,
3553    ) -> bool {
3554        let mut did_extend = false;
3555        new_transforms.update_last(
3556            |last_transform| {
3557                if let DiffTransform::BufferContent {
3558                    summary,
3559                    inserted_hunk_info: inserted_hunk_anchor,
3560                } = last_transform
3561                    && *inserted_hunk_anchor == new_inserted_hunk_info
3562                {
3563                    *summary += summary_to_add;
3564                    did_extend = true;
3565                }
3566            },
3567            (),
3568        );
3569        did_extend
3570    }
3571}
3572
3573fn build_excerpt_ranges(
3574    ranges: impl IntoIterator<Item = Range<Point>>,
3575    context_line_count: u32,
3576    buffer_snapshot: &BufferSnapshot,
3577) -> Vec<ExcerptRange<Point>> {
3578    ranges
3579        .into_iter()
3580        .map(|range| {
3581            let start_row = range.start.row.saturating_sub(context_line_count);
3582            let start = Point::new(start_row, 0);
3583            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3584            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3585            ExcerptRange {
3586                context: start..end,
3587                primary: range,
3588            }
3589        })
3590        .collect()
3591}
3592
3593#[cfg(any(test, feature = "test-support"))]
3594impl MultiBuffer {
3595    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3596        let buffer = cx.new(|cx| Buffer::local(text, cx));
3597        cx.new(|cx| Self::singleton(buffer, cx))
3598    }
3599
3600    pub fn build_multi<const COUNT: usize>(
3601        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3602        cx: &mut gpui::App,
3603    ) -> Entity<Self> {
3604        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3605        for (text, ranges) in excerpts {
3606            let buffer = cx.new(|cx| Buffer::local(text, cx));
3607            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3608            multi.update(cx, |multi, cx| {
3609                multi.push_excerpts(buffer, excerpt_ranges, cx)
3610            });
3611        }
3612
3613        multi
3614    }
3615
3616    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3617        cx.new(|cx| Self::singleton(buffer, cx))
3618    }
3619
3620    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3621        cx.new(|cx| {
3622            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3623            let mutation_count = rng.random_range(1..=5);
3624            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3625            multibuffer
3626        })
3627    }
3628
3629    pub fn randomly_edit(
3630        &mut self,
3631        rng: &mut impl rand::Rng,
3632        edit_count: usize,
3633        cx: &mut Context<Self>,
3634    ) {
3635        use util::RandomCharIter;
3636
3637        let snapshot = self.read(cx);
3638        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3639        let mut last_end = None;
3640        for _ in 0..edit_count {
3641            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3642                break;
3643            }
3644
3645            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3646            let end =
3647                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3648            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3649            last_end = Some(end);
3650
3651            let mut range = start..end;
3652            if rng.random_bool(0.2) {
3653                mem::swap(&mut range.start, &mut range.end);
3654            }
3655
3656            let new_text_len = rng.random_range(0..10);
3657            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3658
3659            edits.push((range, new_text.into()));
3660        }
3661        log::info!("mutating multi-buffer with {:?}", edits);
3662        drop(snapshot);
3663
3664        self.edit(edits, None, cx);
3665    }
3666
3667    pub fn randomly_edit_excerpts(
3668        &mut self,
3669        rng: &mut impl rand::Rng,
3670        mutation_count: usize,
3671        cx: &mut Context<Self>,
3672    ) {
3673        use rand::prelude::*;
3674        use std::env;
3675        use util::RandomCharIter;
3676
3677        let max_excerpts = env::var("MAX_EXCERPTS")
3678            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3679            .unwrap_or(5);
3680
3681        let mut buffers = Vec::new();
3682        for _ in 0..mutation_count {
3683            if rng.random_bool(0.05) {
3684                log::info!("Clearing multi-buffer");
3685                self.clear(cx);
3686                continue;
3687            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3688                let ids = self.excerpt_ids();
3689                let mut excerpts = HashSet::default();
3690                for _ in 0..rng.random_range(0..ids.len()) {
3691                    excerpts.extend(ids.choose(rng).copied());
3692                }
3693
3694                let line_count = rng.random_range(0..5);
3695
3696                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3697
3698                self.expand_excerpts(
3699                    excerpts.iter().cloned(),
3700                    line_count,
3701                    ExpandExcerptDirection::UpAndDown,
3702                    cx,
3703                );
3704                continue;
3705            }
3706
3707            let excerpt_ids = self.excerpt_ids();
3708            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3709                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3710                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3711                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3712                    let buffer = buffers.last().unwrap().read(cx);
3713                    log::info!(
3714                        "Creating new buffer {} with text: {:?}",
3715                        buffer.remote_id(),
3716                        buffer.text()
3717                    );
3718                    buffers.last().unwrap().clone()
3719                } else {
3720                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3721                };
3722
3723                let buffer = buffer_handle.read(cx);
3724                let buffer_text = buffer.text();
3725                let ranges = (0..rng.random_range(0..5))
3726                    .map(|_| {
3727                        let end_ix =
3728                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3729                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3730                        ExcerptRange::new(start_ix..end_ix)
3731                    })
3732                    .collect::<Vec<_>>();
3733                log::info!(
3734                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3735                    buffer_handle.read(cx).remote_id(),
3736                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3737                    ranges
3738                        .iter()
3739                        .map(|r| &buffer_text[r.context.clone()])
3740                        .collect::<Vec<_>>()
3741                );
3742
3743                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3744                log::info!("Inserted with ids: {:?}", excerpt_id);
3745            } else {
3746                let remove_count = rng.random_range(1..=excerpt_ids.len());
3747                let mut excerpts_to_remove = excerpt_ids
3748                    .choose_multiple(rng, remove_count)
3749                    .cloned()
3750                    .collect::<Vec<_>>();
3751                let snapshot = self.snapshot.borrow();
3752                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3753                drop(snapshot);
3754                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3755                self.remove_excerpts(excerpts_to_remove, cx);
3756            }
3757        }
3758    }
3759
3760    pub fn randomly_mutate(
3761        &mut self,
3762        rng: &mut impl rand::Rng,
3763        mutation_count: usize,
3764        cx: &mut Context<Self>,
3765    ) {
3766        use rand::prelude::*;
3767
3768        if rng.random_bool(0.7) || self.singleton {
3769            let buffer = self
3770                .buffers
3771                .values()
3772                .choose(rng)
3773                .map(|state| state.buffer.clone());
3774
3775            if let Some(buffer) = buffer {
3776                buffer.update(cx, |buffer, cx| {
3777                    if rng.random() {
3778                        buffer.randomly_edit(rng, mutation_count, cx);
3779                    } else {
3780                        buffer.randomly_undo_redo(rng, cx);
3781                    }
3782                });
3783            } else {
3784                self.randomly_edit(rng, mutation_count, cx);
3785            }
3786        } else {
3787            self.randomly_edit_excerpts(rng, mutation_count, cx);
3788        }
3789
3790        self.check_invariants(cx);
3791    }
3792
3793    fn check_invariants(&self, cx: &App) {
3794        self.read(cx).check_invariants();
3795    }
3796}
3797
3798impl EventEmitter<Event> for MultiBuffer {}
3799
3800impl MultiBufferSnapshot {
3801    pub fn text(&self) -> String {
3802        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3803            .map(|chunk| chunk.text)
3804            .collect()
3805    }
3806
3807    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3808        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3809            .flat_map(|c| c.chars().rev())
3810    }
3811
3812    fn reversed_chunks_in_range(
3813        &self,
3814        range: Range<MultiBufferOffset>,
3815    ) -> ReversedMultiBufferChunks<'_> {
3816        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3817        cursor.seek(&range.end);
3818        let current_chunks = cursor.region().as_ref().map(|region| {
3819            let start_overshoot = range.start.saturating_sub(region.range.start);
3820            let end_overshoot = range.end - region.range.start;
3821            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3822            let start = region.buffer_range.start + start_overshoot;
3823            region.buffer.reversed_chunks_in_range(start..end)
3824        });
3825        ReversedMultiBufferChunks {
3826            cursor,
3827            current_chunks,
3828            start: range.start,
3829            offset: range.end,
3830        }
3831    }
3832
3833    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3834        let offset = position.to_offset(self);
3835        self.text_for_range(offset..self.len())
3836            .flat_map(|chunk| chunk.chars())
3837    }
3838
3839    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3840        self.chunks(range, false).map(|chunk| chunk.text)
3841    }
3842
3843    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3844        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3845            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3846    }
3847
3848    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3849    where
3850        T: ToOffset,
3851    {
3852        let position = position.to_offset(self);
3853        position == self.clip_offset(position, Bias::Left)
3854            && self
3855                .bytes_in_range(position..self.len())
3856                .flatten()
3857                .copied()
3858                .take(needle.len())
3859                .eq(needle.bytes())
3860    }
3861
3862    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3863        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3864    }
3865
3866    pub fn diff_hunks_in_range<T: ToPoint>(
3867        &self,
3868        range: Range<T>,
3869    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3870        let query_range = range.start.to_point(self)..range.end.to_point(self);
3871        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3872            let diff = self.diffs.get(&buffer.remote_id())?;
3873            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3874                if let Some(main_buffer) = &diff.main_buffer {
3875                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3876                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3877                    Box::new(
3878                        diff.hunks_intersecting_base_text_range(
3879                            buffer_start..buffer_end,
3880                            main_buffer,
3881                        )
3882                        .map(move |hunk| (hunk, buffer, true)),
3883                    )
3884                } else {
3885                    let buffer_start = buffer.anchor_before(buffer_range.start);
3886                    let buffer_end = buffer.anchor_after(buffer_range.end);
3887                    Box::new(
3888                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3889                            .map(move |hunk| (hunk, buffer, false)),
3890                    )
3891                };
3892            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3893                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3894                    return None;
3895                }
3896                let range = if is_inverted {
3897                    hunk.diff_base_byte_range.to_point(&buffer)
3898                } else {
3899                    hunk.range.clone()
3900                };
3901                Some((range, (hunk, is_inverted)))
3902            }))
3903        })
3904        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3905            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3906            {
3907                return None;
3908            }
3909            let end_row = if range.end.column == 0 {
3910                range.end.row
3911            } else {
3912                range.end.row + 1
3913            };
3914
3915            let word_diffs = (!hunk.base_word_diffs.is_empty()
3916                || !hunk.buffer_word_diffs.is_empty())
3917            .then(|| {
3918                let hunk_start_offset = if is_inverted {
3919                    Anchor::in_buffer(
3920                        excerpt.id,
3921                        excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3922                    )
3923                    .to_offset(self)
3924                } else {
3925                    Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_offset(self)
3926                };
3927
3928                let mut word_diffs = hunk
3929                    .base_word_diffs
3930                    .iter()
3931                    .map(|diff| hunk_start_offset + diff.start..hunk_start_offset + diff.end)
3932                    .collect::<Vec<_>>();
3933                if !is_inverted {
3934                    word_diffs.extend(
3935                        hunk.buffer_word_diffs
3936                            .into_iter()
3937                            .map(|diff| Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)),
3938                    );
3939                }
3940                word_diffs
3941            })
3942            .unwrap_or_default();
3943
3944            let buffer_range = if is_inverted {
3945                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3946                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3947            } else {
3948                hunk.buffer_range.clone()
3949            };
3950            Some(MultiBufferDiffHunk {
3951                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3952                buffer_id: excerpt.buffer_id,
3953                excerpt_id: excerpt.id,
3954                buffer_range,
3955                word_diffs,
3956                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3957                    ..BufferOffset(hunk.diff_base_byte_range.end),
3958                secondary_status: hunk.secondary_status,
3959            })
3960        })
3961    }
3962
3963    fn excerpts_for_range<T: ToOffset>(
3964        &self,
3965        range: Range<T>,
3966    ) -> impl Iterator<Item = &Excerpt> + '_ {
3967        let range = range.start.to_offset(self)..range.end.to_offset(self);
3968        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3969        cursor.seek(&range.start);
3970        std::iter::from_fn(move || {
3971            let region = cursor.region()?;
3972            if region.range.start > range.end
3973                || region.range.start == range.end && region.range.start > range.start
3974            {
3975                return None;
3976            }
3977            cursor.next_excerpt();
3978            Some(region.excerpt)
3979        })
3980    }
3981
3982    pub fn excerpt_ids_for_range<T: ToOffset>(
3983        &self,
3984        range: Range<T>,
3985    ) -> impl Iterator<Item = ExcerptId> + '_ {
3986        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3987    }
3988
3989    pub fn buffer_ids_for_range<T: ToOffset>(
3990        &self,
3991        range: Range<T>,
3992    ) -> impl Iterator<Item = BufferId> + '_ {
3993        self.excerpts_for_range(range)
3994            .map(|excerpt| excerpt.buffer_id)
3995    }
3996
3997    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3998        &self,
3999        ranges: impl Iterator<Item = Range<T>>,
4000    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4001        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
4002    }
4003
4004    pub fn range_to_buffer_ranges<T: ToOffset>(
4005        &self,
4006        range: Range<T>,
4007    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4008        let start = range.start.to_offset(self);
4009        let end = range.end.to_offset(self);
4010
4011        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4012        cursor.seek(&start);
4013
4014        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
4015        while let Some(region) = cursor.region() {
4016            if region.range.start > end {
4017                break;
4018            }
4019            if region.is_main_buffer {
4020                let start_overshoot = start.saturating_sub(region.range.start);
4021                let end_overshoot = end.saturating_sub(region.range.start);
4022                let start = region
4023                    .buffer_range
4024                    .end
4025                    .min(region.buffer_range.start + start_overshoot);
4026                let end = region
4027                    .buffer_range
4028                    .end
4029                    .min(region.buffer_range.start + end_overshoot);
4030                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
4031                    *excerpt_id == region.excerpt.id && prev_range.end == start
4032                }) {
4033                    prev.1.end = end;
4034                } else {
4035                    result.push((region.buffer, start..end, region.excerpt.id));
4036                }
4037            }
4038            cursor.next();
4039        }
4040        result
4041    }
4042
4043    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4044        &self,
4045        range: Range<T>,
4046    ) -> impl Iterator<
4047        Item = (
4048            &BufferSnapshot,
4049            Range<BufferOffset>,
4050            ExcerptId,
4051            Option<Anchor>,
4052        ),
4053    > + '_ {
4054        let start = range.start.to_offset(self);
4055        let end = range.end.to_offset(self);
4056
4057        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4058        cursor.seek(&start);
4059
4060        std::iter::from_fn(move || {
4061            let region = cursor.region()?;
4062            if region.range.start > end {
4063                return None;
4064            }
4065            let start_overshoot = start.saturating_sub(region.range.start);
4066            let end_overshoot = end.saturating_sub(region.range.start);
4067            let start = region
4068                .buffer_range
4069                .end
4070                .min(region.buffer_range.start + start_overshoot);
4071            let end = region
4072                .buffer_range
4073                .end
4074                .min(region.buffer_range.start + end_overshoot);
4075
4076            let region_excerpt_id = region.excerpt.id;
4077            let deleted_hunk_anchor = if region.is_main_buffer {
4078                None
4079            } else {
4080                Some(self.anchor_before(region.range.start))
4081            };
4082            let result = (
4083                region.buffer,
4084                start..end,
4085                region_excerpt_id,
4086                deleted_hunk_anchor,
4087            );
4088            cursor.next();
4089            Some(result)
4090        })
4091    }
4092
4093    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4094    /// coordinates.
4095    ///
4096    /// The given callback will be called for every excerpt intersecting the given range. It will
4097    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4098    /// The callback should return an iterator of metadata items from that buffer, each paired
4099    /// with a buffer range.
4100    ///
4101    /// The returned iterator yields each of these metadata items, paired with its range in
4102    /// multi-buffer coordinates.
4103    fn lift_buffer_metadata<'a, MBD, M, I>(
4104        &'a self,
4105        query_range: Range<MBD>,
4106        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4107    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4108    where
4109        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4110        MBD: MultiBufferDimension
4111            + Ord
4112            + Sub<Output = MBD::TextDimension>
4113            + ops::Add<MBD::TextDimension, Output = MBD>
4114            + ops::AddAssign<MBD::TextDimension>,
4115        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4116            + ops::Add<Output = MBD::TextDimension>
4117            + AddAssign<MBD::TextDimension>
4118            + Ord,
4119    {
4120        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4121        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4122
4123        // Find the excerpt and buffer offset where the given range ends.
4124        cursor.seek(&query_range.end);
4125        let mut range_end = None;
4126        while let Some(region) = cursor.region() {
4127            if region.is_main_buffer {
4128                let mut buffer_end = region.buffer_range.start;
4129                let overshoot = if query_range.end > region.range.start {
4130                    query_range.end - region.range.start
4131                } else {
4132                    <MBD::TextDimension>::default()
4133                };
4134                buffer_end = buffer_end + overshoot;
4135                range_end = Some((region.excerpt.id, buffer_end));
4136                break;
4137            }
4138            cursor.next();
4139        }
4140
4141        cursor.seek(&query_range.start);
4142
4143        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4144            && region.range.start > MBD::default()
4145        {
4146            cursor.prev()
4147        }
4148
4149        iter::from_fn(move || {
4150            loop {
4151                let excerpt = cursor.excerpt()?;
4152
4153                // If we have already retrieved metadata for this excerpt, continue to use it.
4154                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4155                    .as_mut()
4156                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4157                {
4158                    Some(metadata)
4159                }
4160                // Otherwise, compute the intersection of the input range with the excerpt's range,
4161                // and retrieve the metadata for the resulting range.
4162                else {
4163                    let region = cursor.region()?;
4164                    let mut buffer_start;
4165                    if region.is_main_buffer {
4166                        buffer_start = region.buffer_range.start;
4167                        if query_range.start > region.range.start {
4168                            let overshoot = query_range.start - region.range.start;
4169                            buffer_start = buffer_start + overshoot;
4170                        }
4171                        buffer_start = buffer_start.min(region.buffer_range.end);
4172                    } else {
4173                        buffer_start = cursor.main_buffer_position()?;
4174                    };
4175                    let mut buffer_end = excerpt
4176                        .range
4177                        .context
4178                        .end
4179                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4180                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4181                        && excerpt.id == end_excerpt_id
4182                    {
4183                        buffer_end = buffer_end.min(end_buffer_offset);
4184                    }
4185
4186                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4187                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4188                    })
4189                };
4190
4191                // Visit each metadata item.
4192                if let Some((metadata_buffer_range, metadata)) =
4193                    metadata_iter.and_then(Iterator::next)
4194                {
4195                    // Find the multibuffer regions that contain the start and end of
4196                    // the metadata item's range.
4197                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4198                        while let Some(region) = cursor.region() {
4199                            if region.is_main_buffer
4200                                && (region.buffer_range.end >= metadata_buffer_range.start
4201                                    || cursor.is_at_end_of_excerpt())
4202                            {
4203                                break;
4204                            }
4205                            cursor.next();
4206                        }
4207                    }
4208                    let start_region = cursor.region()?;
4209                    while let Some(region) = cursor.region() {
4210                        if region.is_main_buffer
4211                            && (region.buffer_range.end > metadata_buffer_range.end
4212                                || cursor.is_at_end_of_excerpt())
4213                        {
4214                            break;
4215                        }
4216                        cursor.next();
4217                    }
4218                    let end_region = cursor.region();
4219
4220                    // Convert the metadata item's range into multibuffer coordinates.
4221                    let mut start_position = start_region.range.start;
4222                    let region_buffer_start = start_region.buffer_range.start;
4223                    if start_region.is_main_buffer
4224                        && metadata_buffer_range.start > region_buffer_start
4225                    {
4226                        start_position =
4227                            start_position + (metadata_buffer_range.start - region_buffer_start);
4228                        start_position = start_position.min(start_region.range.end);
4229                    }
4230
4231                    let mut end_position = self.max_position();
4232                    if let Some(end_region) = &end_region {
4233                        end_position = end_region.range.start;
4234                        debug_assert!(end_region.is_main_buffer);
4235                        let region_buffer_start = end_region.buffer_range.start;
4236                        if metadata_buffer_range.end > region_buffer_start {
4237                            end_position =
4238                                end_position + (metadata_buffer_range.end - region_buffer_start);
4239                        }
4240                        end_position = end_position.min(end_region.range.end);
4241                    }
4242
4243                    if start_position <= query_range.end && end_position >= query_range.start {
4244                        return Some((start_position..end_position, metadata, excerpt));
4245                    }
4246                }
4247                // When there are no more metadata items for this excerpt, move to the next excerpt.
4248                else {
4249                    current_excerpt_metadata.take();
4250                    if let Some((end_excerpt_id, _)) = range_end
4251                        && excerpt.id == end_excerpt_id
4252                    {
4253                        return None;
4254                    }
4255                    cursor.next_excerpt();
4256                }
4257            }
4258        })
4259    }
4260
4261    // FIXME need to make this work with inverted diffs
4262    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4263        let offset = position.to_offset(self);
4264
4265        let mut cursor = self
4266            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4267            );
4268        cursor.seek(&DimensionPair {
4269            key: offset,
4270            value: None,
4271        });
4272        cursor.seek_to_start_of_current_excerpt();
4273        let excerpt = cursor.excerpt()?;
4274
4275        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4276        let current_position = self
4277            .anchor_before(offset)
4278            .text_anchor
4279            .to_offset(&excerpt.buffer);
4280        let excerpt_end = excerpt
4281            .buffer
4282            .anchor_before(excerpt_end.min(current_position));
4283
4284        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4285            for hunk in diff.hunks_intersecting_range_rev(
4286                excerpt.range.context.start..excerpt_end,
4287                &excerpt.buffer,
4288            ) {
4289                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4290                if hunk_end >= current_position {
4291                    continue;
4292                }
4293                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4294                return Some(MultiBufferRow(start.row));
4295            }
4296        }
4297
4298        loop {
4299            cursor.prev_excerpt();
4300            let excerpt = cursor.excerpt()?;
4301
4302            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4303                continue;
4304            };
4305            let mut hunks =
4306                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4307            let Some(hunk) = hunks.next() else {
4308                continue;
4309            };
4310            let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4311            return Some(MultiBufferRow(start.row));
4312        }
4313    }
4314
4315    pub fn has_diff_hunks(&self) -> bool {
4316        self.diffs.values().any(|diff| !diff.is_empty())
4317    }
4318
4319    pub fn is_inside_word<T: ToOffset>(
4320        &self,
4321        position: T,
4322        scope_context: Option<CharScopeContext>,
4323    ) -> bool {
4324        let position = position.to_offset(self);
4325        let classifier = self
4326            .char_classifier_at(position)
4327            .scope_context(scope_context);
4328        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4329        let prev_char_kind = self
4330            .reversed_chars_at(position)
4331            .next()
4332            .map(|c| classifier.kind(c));
4333        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4334    }
4335
4336    pub fn surrounding_word<T: ToOffset>(
4337        &self,
4338        start: T,
4339        scope_context: Option<CharScopeContext>,
4340    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4341        let mut start = start.to_offset(self);
4342        let mut end = start;
4343        let mut next_chars = self.chars_at(start).peekable();
4344        let mut prev_chars = self.reversed_chars_at(start).peekable();
4345
4346        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4347
4348        let word_kind = cmp::max(
4349            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4350            next_chars.peek().copied().map(|c| classifier.kind(c)),
4351        );
4352
4353        for ch in prev_chars {
4354            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4355                start -= ch.len_utf8();
4356            } else {
4357                break;
4358            }
4359        }
4360
4361        for ch in next_chars {
4362            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4363                end += ch.len_utf8();
4364            } else {
4365                break;
4366            }
4367        }
4368
4369        (start..end, word_kind)
4370    }
4371
4372    pub fn char_kind_before<T: ToOffset>(
4373        &self,
4374        start: T,
4375        scope_context: Option<CharScopeContext>,
4376    ) -> Option<CharKind> {
4377        let start = start.to_offset(self);
4378        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4379        self.reversed_chars_at(start)
4380            .next()
4381            .map(|ch| classifier.kind(ch))
4382    }
4383
4384    pub fn is_singleton(&self) -> bool {
4385        self.singleton
4386    }
4387
4388    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4389        if self.singleton {
4390            self.excerpts
4391                .iter()
4392                .next()
4393                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4394        } else {
4395            None
4396        }
4397    }
4398
4399    pub fn len(&self) -> MultiBufferOffset {
4400        self.diff_transforms.summary().output.len
4401    }
4402
4403    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4404        MBD::from_summary(&self.text_summary())
4405    }
4406
4407    pub fn is_empty(&self) -> bool {
4408        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4409    }
4410
4411    pub fn widest_line_number(&self) -> u32 {
4412        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4413        self.excerpts.summary().widest_line_number + 1
4414    }
4415
4416    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4417        let range = range.start.to_offset(self)..range.end.to_offset(self);
4418        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4419        excerpts.seek(&range.start);
4420
4421        let mut chunk;
4422        let mut has_trailing_newline;
4423        let excerpt_bytes;
4424        if let Some(region) = excerpts.region() {
4425            let mut bytes = region.buffer.bytes_in_range(
4426                region.buffer_range.start + (range.start - region.range.start)
4427                    ..(region.buffer_range.start + (range.end - region.range.start))
4428                        .min(region.buffer_range.end),
4429            );
4430            chunk = bytes.next().unwrap_or(&[][..]);
4431            excerpt_bytes = Some(bytes);
4432            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4433            if chunk.is_empty() && has_trailing_newline {
4434                chunk = b"\n";
4435                has_trailing_newline = false;
4436            }
4437        } else {
4438            chunk = &[][..];
4439            excerpt_bytes = None;
4440            has_trailing_newline = false;
4441        };
4442
4443        MultiBufferBytes {
4444            range,
4445            cursor: excerpts,
4446            excerpt_bytes,
4447            has_trailing_newline,
4448            chunk,
4449        }
4450    }
4451
4452    pub fn reversed_bytes_in_range<T: ToOffset>(
4453        &self,
4454        range: Range<T>,
4455    ) -> ReversedMultiBufferBytes<'_> {
4456        let range = range.start.to_offset(self)..range.end.to_offset(self);
4457        let mut chunks = self.reversed_chunks_in_range(range.clone());
4458        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4459        ReversedMultiBufferBytes {
4460            range,
4461            chunks,
4462            chunk,
4463        }
4464    }
4465
4466    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4467        let mut cursor = self.cursor::<Point, Point>();
4468        cursor.seek(&Point::new(start_row.0, 0));
4469        let mut result = MultiBufferRows {
4470            point: Point::new(0, 0),
4471            is_empty: self.excerpts.is_empty(),
4472            is_singleton: self.is_singleton(),
4473            cursor,
4474        };
4475        result.seek(start_row);
4476        result
4477    }
4478
4479    pub fn chunks<T: ToOffset>(
4480        &self,
4481        range: Range<T>,
4482        language_aware: bool,
4483    ) -> MultiBufferChunks<'_> {
4484        let mut chunks = MultiBufferChunks {
4485            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4486                ..ExcerptDimension(MultiBufferOffset::ZERO),
4487            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4488            excerpts: self.excerpts.cursor(()),
4489            diff_transforms: self.diff_transforms.cursor(()),
4490            diffs: &self.diffs,
4491            diff_base_chunks: None,
4492            excerpt_chunks: None,
4493            buffer_chunk: None,
4494            language_aware,
4495        };
4496        let range = range.start.to_offset(self)..range.end.to_offset(self);
4497        chunks.seek(range);
4498        chunks
4499    }
4500
4501    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4502        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4503    }
4504
4505    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4506        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4507    }
4508
4509    pub fn clip_offset_utf16(
4510        &self,
4511        offset: MultiBufferOffsetUtf16,
4512        bias: Bias,
4513    ) -> MultiBufferOffsetUtf16 {
4514        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4515    }
4516
4517    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4518        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4519            buffer.clip_point_utf16(Unclipped(point), bias)
4520        })
4521    }
4522
4523    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4524        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4525    }
4526
4527    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4528        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4529    }
4530
4531    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4532        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4533    }
4534
4535    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4536        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4537    }
4538
4539    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4540        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4541    }
4542
4543    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4544        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4545    }
4546
4547    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4548        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4549    }
4550
4551    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4552        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4553    }
4554
4555    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4556        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4557    }
4558
4559    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4560        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4561    }
4562
4563    fn clip_dimension<MBD, BD>(
4564        &self,
4565        position: MBD,
4566        bias: Bias,
4567        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4568    ) -> MBD
4569    where
4570        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4571        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4572    {
4573        let mut cursor = self.cursor::<MBD, BD>();
4574        cursor.seek(&position);
4575        if let Some(region) = cursor.region() {
4576            if position >= region.range.end {
4577                return region.range.end;
4578            }
4579            let overshoot = position - region.range.start;
4580            let mut buffer_position = region.buffer_range.start;
4581            buffer_position += overshoot;
4582            let clipped_buffer_position =
4583                clip_buffer_position(region.buffer, buffer_position, bias);
4584            let mut position = region.range.start;
4585            position += clipped_buffer_position - region.buffer_range.start;
4586            position
4587        } else {
4588            self.max_position()
4589        }
4590    }
4591
4592    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4593        &self,
4594        key: MBR1,
4595        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4596    ) -> MBR2
4597    where
4598        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4599        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4600        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4601        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4602    {
4603        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4604        cursor.seek(&DimensionPair { key, value: None });
4605        if let Some(region) = cursor.region() {
4606            if key >= region.range.end.key {
4607                return region.range.end.value.unwrap();
4608            }
4609            let start_key = region.range.start.key;
4610            let start_value = region.range.start.value.unwrap();
4611            let buffer_start_key = region.buffer_range.start.key;
4612            let buffer_start_value = region.buffer_range.start.value.unwrap();
4613            let mut buffer_key = buffer_start_key;
4614            buffer_key += key - start_key;
4615            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4616            let mut result = start_value;
4617            result += buffer_value - buffer_start_value;
4618            result
4619        } else {
4620            self.max_position()
4621        }
4622    }
4623
4624    pub fn point_to_buffer_offset<T: ToOffset>(
4625        &self,
4626        point: T,
4627    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4628        let offset = point.to_offset(self);
4629        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4630        cursor.seek(&offset);
4631        let region = cursor.region()?;
4632        let overshoot = offset - region.range.start;
4633        let buffer_offset = region.buffer_range.start + overshoot;
4634        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4635            && region.has_trailing_newline
4636            && !region.is_main_buffer
4637        {
4638            let main_buffer_position = cursor.main_buffer_position()?;
4639            let buffer_snapshot = &cursor.excerpt()?.buffer;
4640            return Some((buffer_snapshot, main_buffer_position));
4641        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4642            return None;
4643        }
4644        Some((region.buffer, buffer_offset))
4645    }
4646
4647    pub fn point_to_buffer_point(
4648        &self,
4649        point: Point,
4650    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4651        let mut cursor = self.cursor::<Point, Point>();
4652        cursor.seek(&point);
4653        let region = cursor.region()?;
4654        let overshoot = point - region.range.start;
4655        let buffer_point = region.buffer_range.start + overshoot;
4656        let excerpt = cursor.excerpt()?;
4657        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4658            && region.has_trailing_newline
4659            && !region.is_main_buffer
4660        {
4661            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4662        } else if buffer_point > region.buffer.max_point() {
4663            return None;
4664        }
4665        Some((region.buffer, buffer_point, excerpt.id))
4666    }
4667
4668    pub fn suggested_indents(
4669        &self,
4670        rows: impl IntoIterator<Item = u32>,
4671        cx: &App,
4672    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4673        let mut result = BTreeMap::new();
4674
4675        let mut rows_for_excerpt = Vec::new();
4676        let mut cursor = self.cursor::<Point, Point>();
4677        let mut rows = rows.into_iter().peekable();
4678        let mut prev_row = u32::MAX;
4679        let mut prev_language_indent_size = IndentSize::default();
4680
4681        while let Some(row) = rows.next() {
4682            cursor.seek(&Point::new(row, 0));
4683            let Some(region) = cursor.region() else {
4684                continue;
4685            };
4686
4687            // Retrieve the language and indent size once for each disjoint region being indented.
4688            let single_indent_size = if row.saturating_sub(1) == prev_row {
4689                prev_language_indent_size
4690            } else {
4691                region
4692                    .buffer
4693                    .language_indent_size_at(Point::new(row, 0), cx)
4694            };
4695            prev_language_indent_size = single_indent_size;
4696            prev_row = row;
4697
4698            let start_buffer_row = region.buffer_range.start.row;
4699            let start_multibuffer_row = region.range.start.row;
4700            let end_multibuffer_row = region.range.end.row;
4701
4702            rows_for_excerpt.push(row);
4703            while let Some(next_row) = rows.peek().copied() {
4704                if end_multibuffer_row > next_row {
4705                    rows_for_excerpt.push(next_row);
4706                    rows.next();
4707                } else {
4708                    break;
4709                }
4710            }
4711
4712            let buffer_rows = rows_for_excerpt
4713                .drain(..)
4714                .map(|row| start_buffer_row + row - start_multibuffer_row);
4715            let buffer_indents = region
4716                .buffer
4717                .suggested_indents(buffer_rows, single_indent_size);
4718            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4719                (
4720                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4721                    indent,
4722                )
4723            });
4724            result.extend(multibuffer_indents);
4725        }
4726
4727        result
4728    }
4729
4730    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4731        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4732            let mut size = buffer.indent_size_for_line(range.start.row);
4733            size.len = size
4734                .len
4735                .min(range.end.column)
4736                .saturating_sub(range.start.column);
4737            size
4738        } else {
4739            IndentSize::spaces(0)
4740        }
4741    }
4742
4743    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4744        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4745            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4746        } else {
4747            LineIndent::spaces(0)
4748        }
4749    }
4750
4751    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4752        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4753
4754        if self.language_settings(cx).extend_comment_on_newline
4755            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4756        {
4757            let delimiters = language_scope.line_comment_prefixes();
4758            for delimiter in delimiters {
4759                if *self
4760                    .chars_at(Point::new(row.0, indent.len() as u32))
4761                    .take(delimiter.chars().count())
4762                    .collect::<String>()
4763                    .as_str()
4764                    == **delimiter
4765                {
4766                    indent.push_str(delimiter);
4767                    break;
4768                }
4769            }
4770        }
4771
4772        indent
4773    }
4774
4775    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4776    where
4777        T: ToOffset,
4778    {
4779        for char in self.reversed_chars_at(position) {
4780            if !char.is_whitespace() {
4781                return false;
4782            }
4783            if char == '\n' {
4784                return true;
4785            }
4786        }
4787        true
4788    }
4789
4790    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4791        while row.0 > 0 {
4792            row.0 -= 1;
4793            if !self.is_line_blank(row) {
4794                return Some(row);
4795            }
4796        }
4797        None
4798    }
4799
4800    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4801        if let Some((_, range)) = self.buffer_line_for_row(row) {
4802            range.end.column - range.start.column
4803        } else {
4804            0
4805        }
4806    }
4807
4808    pub fn buffer_line_for_row(
4809        &self,
4810        row: MultiBufferRow,
4811    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4812        let mut cursor = self.cursor::<Point, Point>();
4813        let point = Point::new(row.0, 0);
4814        cursor.seek(&point);
4815        let region = cursor.region()?;
4816        let overshoot = point.min(region.range.end) - region.range.start;
4817        let buffer_point = region.buffer_range.start + overshoot;
4818        if buffer_point.row > region.buffer_range.end.row {
4819            return None;
4820        }
4821        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4822        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4823            .min(region.buffer_range.end);
4824        Some((region.buffer, line_start..line_end))
4825    }
4826
4827    pub fn max_point(&self) -> Point {
4828        self.text_summary().lines
4829    }
4830
4831    pub fn max_row(&self) -> MultiBufferRow {
4832        MultiBufferRow(self.text_summary().lines.row)
4833    }
4834
4835    pub fn text_summary(&self) -> MBTextSummary {
4836        self.diff_transforms.summary().output
4837    }
4838
4839    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4840    where
4841        MBD: MultiBufferDimension + AddAssign,
4842        O: ToOffset,
4843    {
4844        let range = range.start.to_offset(self)..range.end.to_offset(self);
4845        let mut cursor = self
4846            .diff_transforms
4847            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4848        cursor.seek(&range.start, Bias::Right);
4849
4850        let Some(first_transform) = cursor.item() else {
4851            return MBD::from_summary(&MBTextSummary::default());
4852        };
4853
4854        let diff_transform_start = cursor.start().0;
4855        let diff_transform_end = cursor.end().0;
4856        let diff_start = range.start;
4857        let start_overshoot = diff_start - diff_transform_start;
4858        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4859
4860        let mut result = match first_transform {
4861            DiffTransform::BufferContent { .. } => {
4862                let excerpt_start = cursor.start().1 + start_overshoot;
4863                let excerpt_end = cursor.start().1 + end_overshoot;
4864                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4865            }
4866            DiffTransform::DeletedHunk {
4867                buffer_id,
4868                base_text_byte_range,
4869                has_trailing_newline,
4870                ..
4871            } => {
4872                let buffer_start = base_text_byte_range.start + start_overshoot;
4873                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4874                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4875                    panic!("{:?} is in non-existent deleted hunk", range.start)
4876                };
4877
4878                let include_trailing_newline =
4879                    *has_trailing_newline && range.end >= diff_transform_end;
4880                if include_trailing_newline {
4881                    buffer_end -= 1;
4882                }
4883
4884                let mut summary = base_text
4885                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4886
4887                if include_trailing_newline {
4888                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4889                        &TextSummary::newline(),
4890                    ))
4891                }
4892
4893                let mut result = MBD::default();
4894                result.add_text_dim(&summary);
4895                result
4896            }
4897        };
4898        if range.end < diff_transform_end {
4899            return result;
4900        }
4901
4902        cursor.next();
4903        result.add_mb_text_summary(
4904            &cursor
4905                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4906                .0,
4907        );
4908
4909        let Some(last_transform) = cursor.item() else {
4910            return result;
4911        };
4912
4913        let overshoot = range.end - cursor.start().0;
4914        let suffix = match last_transform {
4915            DiffTransform::BufferContent { .. } => {
4916                let end = cursor.start().1 + overshoot;
4917                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4918            }
4919            DiffTransform::DeletedHunk {
4920                base_text_byte_range,
4921                buffer_id,
4922                has_trailing_newline,
4923                ..
4924            } => {
4925                let buffer_end = base_text_byte_range.start + overshoot;
4926                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4927                    panic!("{:?} is in non-existent deleted hunk", range.end)
4928                };
4929
4930                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4931                    base_text_byte_range.start..buffer_end,
4932                );
4933                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4934                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4935                        &TextSummary::from("\n"),
4936                    ))
4937                }
4938
4939                let mut result = MBD::default();
4940                result.add_text_dim(&suffix);
4941                result
4942            }
4943        };
4944
4945        result += suffix;
4946        result
4947    }
4948
4949    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4950    where
4951        MBD: MultiBufferDimension + AddAssign,
4952    {
4953        let mut summary = MBD::default();
4954        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4955        cursor.seek(&range.start, Bias::Right);
4956        if let Some(excerpt) = cursor.item() {
4957            let mut end_before_newline = cursor.end();
4958            if excerpt.has_trailing_newline {
4959                end_before_newline -= 1;
4960            }
4961
4962            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4963            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4964            let end_in_excerpt =
4965                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4966            summary.add_text_dim(
4967                &excerpt
4968                    .buffer
4969                    .text_summary_for_range::<MBD::TextDimension, _>(
4970                        start_in_excerpt..end_in_excerpt,
4971                    ),
4972            );
4973
4974            if range.end > end_before_newline {
4975                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4976            }
4977
4978            cursor.next();
4979        }
4980
4981        if range.end > *cursor.start() {
4982            summary += cursor
4983                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4984                .0;
4985            if let Some(excerpt) = cursor.item() {
4986                range.end = cmp::max(*cursor.start(), range.end);
4987
4988                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4989                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4990                summary.add_text_dim(
4991                    &excerpt
4992                        .buffer
4993                        .text_summary_for_range::<MBD::TextDimension, _>(
4994                            excerpt_start..end_in_excerpt,
4995                        ),
4996                );
4997            }
4998        }
4999
5000        summary
5001    }
5002
5003    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5004    where
5005        MBD: MultiBufferDimension
5006            + Ord
5007            + Sub<Output = MBD::TextDimension>
5008            + AddAssign<MBD::TextDimension>,
5009        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5010    {
5011        self.summaries_for_anchors([anchor])[0]
5012    }
5013
5014    fn resolve_summary_for_anchor<MBD>(
5015        &self,
5016        anchor: &Anchor,
5017        excerpt_position: ExcerptDimension<MBD>,
5018        diff_transforms: &mut Cursor<
5019            DiffTransform,
5020            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5021        >,
5022    ) -> MBD
5023    where
5024        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5025    {
5026        loop {
5027            let transform_end_position = diff_transforms.end().0;
5028            let at_transform_end =
5029                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5030            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5031                diff_transforms.next();
5032                continue;
5033            }
5034
5035            let mut position = diff_transforms.start().1;
5036            match diff_transforms.item() {
5037                Some(DiffTransform::DeletedHunk {
5038                    buffer_id,
5039                    base_text_byte_range,
5040                    ..
5041                }) => {
5042                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5043                        && let Some(base_text) =
5044                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5045                        && diff_base_anchor.is_valid(&base_text)
5046                    {
5047                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5048                        if base_text_offset >= base_text_byte_range.start
5049                            && base_text_offset <= base_text_byte_range.end
5050                        {
5051                            let position_in_hunk = base_text
5052                                .text_summary_for_range::<MBD::TextDimension, _>(
5053                                    base_text_byte_range.start..base_text_offset,
5054                                );
5055                            position.0.add_text_dim(&position_in_hunk);
5056                        } else if at_transform_end {
5057                            diff_transforms.next();
5058                            continue;
5059                        }
5060                    }
5061                }
5062                _ => {
5063                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5064                        diff_transforms.next();
5065                        continue;
5066                    }
5067                    let overshoot = excerpt_position - diff_transforms.start().0;
5068                    position += overshoot;
5069                }
5070            }
5071
5072            return position.0;
5073        }
5074    }
5075
5076    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5077        let mut cursor = self
5078            .excerpts
5079            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5080        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5081
5082        cursor.seek(&Some(locator), Bias::Left);
5083        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5084            cursor.prev();
5085        }
5086
5087        let mut position = cursor.start().1;
5088        if let Some(excerpt) = cursor.item()
5089            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5090        {
5091            let excerpt_buffer_start = excerpt
5092                .buffer
5093                .offset_for_anchor(&excerpt.range.context.start);
5094            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5095            let buffer_position = cmp::min(
5096                excerpt_buffer_end,
5097                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5098            );
5099            if buffer_position > excerpt_buffer_start {
5100                position += buffer_position - excerpt_buffer_start;
5101            }
5102        }
5103        position
5104    }
5105
5106    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5107        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5108            excerpt_id = *replacement;
5109        }
5110        excerpt_id
5111    }
5112
5113    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5114    where
5115        MBD: MultiBufferDimension
5116            + Ord
5117            + Sub<Output = MBD::TextDimension>
5118            + AddAssign<MBD::TextDimension>,
5119        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5120        I: 'a + IntoIterator<Item = &'a Anchor>,
5121    {
5122        let mut anchors = anchors.into_iter().peekable();
5123        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5124        let mut diff_transforms_cursor = self
5125            .diff_transforms
5126            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5127        diff_transforms_cursor.next();
5128
5129        let mut summaries = Vec::new();
5130        while let Some(anchor) = anchors.peek() {
5131            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5132
5133            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5134                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5135            });
5136
5137            let locator = self.excerpt_locator_for_id(excerpt_id);
5138            cursor.seek_forward(locator, Bias::Left);
5139            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5140                cursor.prev();
5141            }
5142
5143            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5144            if let Some(excerpt) = cursor.item() {
5145                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5146                    let position = self.resolve_summary_for_anchor(
5147                        &Anchor::min(),
5148                        excerpt_start_position,
5149                        &mut diff_transforms_cursor,
5150                    );
5151                    summaries.extend(excerpt_anchors.map(|_| position));
5152                    continue;
5153                }
5154                let excerpt_buffer_start = excerpt
5155                    .range
5156                    .context
5157                    .start
5158                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5159                let excerpt_buffer_end = excerpt
5160                    .range
5161                    .context
5162                    .end
5163                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5164                for (buffer_summary, anchor) in excerpt
5165                    .buffer
5166                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5167                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5168                    )
5169                {
5170                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5171                    let mut position = excerpt_start_position;
5172                    if summary > excerpt_buffer_start {
5173                        position += summary - excerpt_buffer_start;
5174                    }
5175
5176                    if diff_transforms_cursor.start().0 < position {
5177                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5178                    }
5179
5180                    summaries.push(self.resolve_summary_for_anchor(
5181                        anchor,
5182                        position,
5183                        &mut diff_transforms_cursor,
5184                    ));
5185                }
5186            } else {
5187                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5188                let position = self.resolve_summary_for_anchor(
5189                    &Anchor::max(),
5190                    excerpt_start_position,
5191                    &mut diff_transforms_cursor,
5192                );
5193                summaries.extend(excerpt_anchors.map(|_| position));
5194            }
5195        }
5196
5197        summaries
5198    }
5199
5200    pub fn dimensions_from_points<'a, MBD>(
5201        &'a self,
5202        points: impl 'a + IntoIterator<Item = Point>,
5203    ) -> impl 'a + Iterator<Item = MBD>
5204    where
5205        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5206    {
5207        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5208        cursor.seek(&DimensionPair {
5209            key: Point::default(),
5210            value: None,
5211        });
5212        let mut points = points.into_iter();
5213        iter::from_fn(move || {
5214            let point = points.next()?;
5215
5216            cursor.seek_forward(&DimensionPair {
5217                key: point,
5218                value: None,
5219            });
5220
5221            if let Some(region) = cursor.region() {
5222                let overshoot = point - region.range.start.key;
5223                let buffer_point = region.buffer_range.start + overshoot;
5224                let mut position = region.range.start.value.unwrap();
5225                position.add_text_dim(
5226                    &region
5227                        .buffer
5228                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5229                );
5230                if point == region.range.end.key && region.has_trailing_newline {
5231                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5232                }
5233                Some(position)
5234            } else {
5235                Some(MBD::from_summary(&self.text_summary()))
5236            }
5237        })
5238    }
5239
5240    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5241    where
5242        I: 'a + IntoIterator<Item = &'a Anchor>,
5243    {
5244        let mut anchors = anchors.into_iter().enumerate().peekable();
5245        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5246        cursor.next();
5247
5248        let mut result = Vec::new();
5249
5250        while let Some((_, anchor)) = anchors.peek() {
5251            let old_excerpt_id = anchor.excerpt_id;
5252
5253            // Find the location where this anchor's excerpt should be.
5254            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5255            cursor.seek_forward(&Some(old_locator), Bias::Left);
5256
5257            let next_excerpt = cursor.item();
5258            let prev_excerpt = cursor.prev_item();
5259
5260            // Process all of the anchors for this excerpt.
5261            while let Some((anchor_ix, &anchor)) =
5262                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5263            {
5264                let mut anchor = anchor;
5265
5266                // Leave min and max anchors unchanged if invalid or
5267                // if the old excerpt still exists at this location
5268                let mut kept_position = next_excerpt
5269                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5270                    || old_excerpt_id == ExcerptId::max()
5271                    || old_excerpt_id == ExcerptId::min();
5272
5273                // If the old excerpt no longer exists at this location, then attempt to
5274                // find an equivalent position for this anchor in an adjacent excerpt.
5275                if !kept_position {
5276                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5277                        if excerpt.contains(&anchor) {
5278                            anchor.excerpt_id = excerpt.id;
5279                            kept_position = true;
5280                            break;
5281                        }
5282                    }
5283                }
5284
5285                // If there's no adjacent excerpt that contains the anchor's position,
5286                // then report that the anchor has lost its position.
5287                if !kept_position {
5288                    anchor = if let Some(excerpt) = next_excerpt {
5289                        let mut text_anchor = excerpt
5290                            .range
5291                            .context
5292                            .start
5293                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5294                        if text_anchor
5295                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5296                            .is_gt()
5297                        {
5298                            text_anchor = excerpt.range.context.end;
5299                        }
5300                        Anchor::in_buffer(excerpt.id, text_anchor)
5301                    } else if let Some(excerpt) = prev_excerpt {
5302                        let mut text_anchor = excerpt
5303                            .range
5304                            .context
5305                            .end
5306                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5307                        if text_anchor
5308                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5309                            .is_lt()
5310                        {
5311                            text_anchor = excerpt.range.context.start;
5312                        }
5313                        Anchor::in_buffer(excerpt.id, text_anchor)
5314                    } else if anchor.text_anchor.bias == Bias::Left {
5315                        Anchor::min()
5316                    } else {
5317                        Anchor::max()
5318                    };
5319                }
5320
5321                result.push((anchor_ix, anchor, kept_position));
5322            }
5323        }
5324        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5325        result
5326    }
5327
5328    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5329        self.anchor_at(position, Bias::Left)
5330    }
5331
5332    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5333        self.anchor_at(position, Bias::Right)
5334    }
5335
5336    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5337        let offset = position.to_offset(self);
5338
5339        // Find the given position in the diff transforms. Determine the corresponding
5340        // offset in the excerpts, and whether the position is within a deleted hunk.
5341        let mut diff_transforms = self
5342            .diff_transforms
5343            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5344        diff_transforms.seek(&offset, Bias::Right);
5345
5346        if offset == diff_transforms.start().0
5347            && bias == Bias::Left
5348            && let Some(prev_item) = diff_transforms.prev_item()
5349            && let DiffTransform::DeletedHunk { .. } = prev_item
5350        {
5351            diff_transforms.prev();
5352        }
5353        let offset_in_transform = offset - diff_transforms.start().0;
5354        let mut excerpt_offset = diff_transforms.start().1;
5355        let mut diff_base_anchor = None;
5356        if let Some(DiffTransform::DeletedHunk {
5357            buffer_id,
5358            base_text_byte_range,
5359            has_trailing_newline,
5360            ..
5361        }) = diff_transforms.item()
5362        {
5363            let diff = self.diffs.get(buffer_id).expect("missing diff");
5364            if offset_in_transform > base_text_byte_range.len() {
5365                debug_assert!(*has_trailing_newline);
5366                bias = Bias::Right;
5367            } else {
5368                diff_base_anchor = Some(
5369                    diff.base_text()
5370                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5371                );
5372                bias = Bias::Left;
5373            }
5374        } else {
5375            excerpt_offset += MultiBufferOffset(offset_in_transform);
5376        };
5377
5378        let mut excerpts = self
5379            .excerpts
5380            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5381        excerpts.seek(&excerpt_offset, Bias::Right);
5382        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5383            excerpts.prev();
5384        }
5385        if let Some(excerpt) = excerpts.item() {
5386            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5387            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5388                overshoot -= 1;
5389                bias = Bias::Right;
5390            }
5391
5392            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5393            let text_anchor =
5394                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5395            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5396            match diff_base_anchor {
5397                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5398                None => anchor,
5399            }
5400        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5401        {
5402            Anchor::min()
5403        } else {
5404            Anchor::max()
5405        }
5406    }
5407
5408    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5409    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5410        let (excerpt, buffer, _) = self.as_singleton()?;
5411        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5412            Some(Anchor::in_buffer(*excerpt, text_anchor))
5413        } else {
5414            None
5415        }
5416    }
5417
5418    /// Returns an anchor for the given excerpt and text anchor,
5419    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5420    pub fn anchor_range_in_excerpt(
5421        &self,
5422        excerpt_id: ExcerptId,
5423        text_anchor: Range<text::Anchor>,
5424    ) -> Option<Range<Anchor>> {
5425        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5426
5427        Some(
5428            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5429                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5430        )
5431    }
5432
5433    /// Returns an anchor for the given excerpt and text anchor,
5434    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5435    pub fn anchor_in_excerpt(
5436        &self,
5437        excerpt_id: ExcerptId,
5438        text_anchor: text::Anchor,
5439    ) -> Option<Anchor> {
5440        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5441        Self::anchor_in_excerpt_(excerpt, text_anchor)
5442    }
5443
5444    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5445    pub fn anchors_in_excerpt(
5446        &self,
5447        excerpt_id: ExcerptId,
5448        text_anchors: impl IntoIterator<Item = text::Anchor>,
5449    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5450        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5451        Some(
5452            text_anchors
5453                .into_iter()
5454                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5455        )
5456    }
5457
5458    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5459        match text_anchor.buffer_id {
5460            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5461            Some(_) => return None,
5462            None if text_anchor.is_max() || text_anchor.is_min() => {
5463                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5464            }
5465            None => return None,
5466        }
5467
5468        let context = &excerpt.range.context;
5469        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5470            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5471        {
5472            return None;
5473        }
5474
5475        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5476    }
5477
5478    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5479        Some(self.excerpt(excerpt_id)?.range.context.clone())
5480    }
5481
5482    pub fn excerpt_range_for_excerpt(
5483        &self,
5484        excerpt_id: ExcerptId,
5485    ) -> Option<ExcerptRange<text::Anchor>> {
5486        Some(self.excerpt(excerpt_id)?.range.clone())
5487    }
5488
5489    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5490        if anchor.is_min() || anchor.is_max() {
5491            // todo(lw): should be `!self.is_empty()`
5492            true
5493        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5494            excerpt.buffer.can_resolve(&anchor.text_anchor)
5495        } else {
5496            false
5497        }
5498    }
5499
5500    pub fn excerpts(
5501        &self,
5502    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5503        self.excerpts
5504            .iter()
5505            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5506    }
5507
5508    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5509    where
5510        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5511        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5512    {
5513        let excerpts = self.excerpts.cursor(());
5514        let diff_transforms = self.diff_transforms.cursor(());
5515        MultiBufferCursor {
5516            excerpts,
5517            diff_transforms,
5518            diffs: &self.diffs,
5519            cached_region: None,
5520        }
5521    }
5522
5523    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5524        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5525        let mut excerpts = self
5526            .excerpts
5527            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5528        excerpts.seek(&Some(start_locator), Bias::Left);
5529        excerpts.prev();
5530
5531        let mut diff_transforms = self
5532            .diff_transforms
5533            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5534        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5535        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5536            diff_transforms.next();
5537        }
5538
5539        let excerpt = excerpts.item()?;
5540        Some(MultiBufferExcerpt {
5541            excerpt,
5542            offset: diff_transforms.start().output_dimension.0,
5543            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5544            excerpt_offset: excerpts.start().1,
5545            diff_transforms,
5546        })
5547    }
5548
5549    pub fn excerpt_boundaries_in_range<R, T>(
5550        &self,
5551        range: R,
5552    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5553    where
5554        R: RangeBounds<T>,
5555        T: ToOffset,
5556    {
5557        let start_offset;
5558        let start = match range.start_bound() {
5559            Bound::Included(start) => {
5560                start_offset = start.to_offset(self);
5561                Bound::Included(start_offset)
5562            }
5563            Bound::Excluded(_) => {
5564                panic!("not supported")
5565            }
5566            Bound::Unbounded => {
5567                start_offset = MultiBufferOffset::ZERO;
5568                Bound::Unbounded
5569            }
5570        };
5571        let end = match range.end_bound() {
5572            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5573            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5574            Bound::Unbounded => Bound::Unbounded,
5575        };
5576        let bounds = (start, end);
5577        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5578        cursor.seek(&DimensionPair {
5579            key: start_offset,
5580            value: None,
5581        });
5582
5583        if cursor
5584            .region()
5585            .is_some_and(|region| bounds.contains(&region.range.start.key))
5586        {
5587            cursor.prev_excerpt();
5588        } else {
5589            cursor.seek_to_start_of_current_excerpt();
5590        }
5591        let mut prev_region = cursor.region();
5592
5593        cursor.next_excerpt();
5594
5595        iter::from_fn(move || {
5596            loop {
5597                if self.singleton {
5598                    return None;
5599                }
5600
5601                let next_region = cursor.region()?;
5602                cursor.next_excerpt();
5603                if !bounds.contains(&next_region.range.start.key) {
5604                    prev_region = Some(next_region);
5605                    continue;
5606                }
5607
5608                let next_region_start = next_region.range.start.value.unwrap();
5609                let next_region_end = if let Some(region) = cursor.region() {
5610                    region.range.start.value.unwrap()
5611                } else {
5612                    self.max_point()
5613                };
5614
5615                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5616                    id: region.excerpt.id,
5617                    buffer: region.excerpt.buffer.clone(),
5618                    buffer_id: region.excerpt.buffer_id,
5619                    range: region.excerpt.range.clone(),
5620                    end_row: MultiBufferRow(next_region_start.row),
5621                });
5622
5623                let next = ExcerptInfo {
5624                    id: next_region.excerpt.id,
5625                    buffer: next_region.excerpt.buffer.clone(),
5626                    buffer_id: next_region.excerpt.buffer_id,
5627                    range: next_region.excerpt.range.clone(),
5628                    end_row: if next_region.excerpt.has_trailing_newline {
5629                        MultiBufferRow(next_region_end.row - 1)
5630                    } else {
5631                        MultiBufferRow(next_region_end.row)
5632                    },
5633                };
5634
5635                let row = MultiBufferRow(next_region_start.row);
5636
5637                prev_region = Some(next_region);
5638
5639                return Some(ExcerptBoundary { row, prev, next });
5640            }
5641        })
5642    }
5643
5644    pub fn edit_count(&self) -> usize {
5645        self.edit_count
5646    }
5647
5648    pub fn non_text_state_update_count(&self) -> usize {
5649        self.non_text_state_update_count
5650    }
5651
5652    /// Returns the smallest enclosing bracket ranges containing the given range or
5653    /// None if no brackets contain range or the range is not contained in a single
5654    /// excerpt
5655    ///
5656    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5657    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5658        &self,
5659        range: Range<T>,
5660        range_filter: Option<
5661            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5662        >,
5663    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5664        let range = range.start.to_offset(self)..range.end.to_offset(self);
5665        let mut excerpt = self.excerpt_containing(range.clone())?;
5666        let buffer = excerpt.buffer();
5667        let excerpt_buffer_range = excerpt.buffer_range();
5668
5669        // Filter to ranges contained in the excerpt
5670        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5671            excerpt_buffer_range.contains(&BufferOffset(open.start))
5672                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5673                && range_filter.is_none_or(|filter| {
5674                    filter(
5675                        buffer,
5676                        BufferOffset(open.start)..BufferOffset(close.end),
5677                        BufferOffset(close.start)..BufferOffset(close.end),
5678                    )
5679                })
5680        };
5681
5682        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5683            excerpt.map_range_to_buffer(range),
5684            Some(&range_filter),
5685        )?;
5686
5687        Some((
5688            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5689            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5690        ))
5691    }
5692
5693    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5694    /// not contained in a single excerpt
5695    pub fn enclosing_bracket_ranges<T: ToOffset>(
5696        &self,
5697        range: Range<T>,
5698    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5699    {
5700        let range = range.start.to_offset(self)..range.end.to_offset(self);
5701        let mut excerpt = self.excerpt_containing(range.clone())?;
5702
5703        Some(
5704            excerpt
5705                .buffer()
5706                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5707                .filter_map(move |pair| {
5708                    let open_range =
5709                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5710                    let close_range =
5711                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5712                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5713                        Some((
5714                            excerpt.map_range_from_buffer(open_range),
5715                            excerpt.map_range_from_buffer(close_range),
5716                        ))
5717                    } else {
5718                        None
5719                    }
5720                }),
5721        )
5722    }
5723
5724    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5725    /// not contained in a single excerpt
5726    pub fn text_object_ranges<T: ToOffset>(
5727        &self,
5728        range: Range<T>,
5729        options: TreeSitterOptions,
5730    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5731        let range = range.start.to_offset(self)..range.end.to_offset(self);
5732        self.excerpt_containing(range.clone())
5733            .map(|mut excerpt| {
5734                excerpt
5735                    .buffer()
5736                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5737                    .filter_map(move |(range, text_object)| {
5738                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5739                        if excerpt.contains_buffer_range(range.clone()) {
5740                            Some((excerpt.map_range_from_buffer(range), text_object))
5741                        } else {
5742                            None
5743                        }
5744                    })
5745            })
5746            .into_iter()
5747            .flatten()
5748    }
5749
5750    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5751    /// not contained in a single excerpt
5752    pub fn bracket_ranges<T: ToOffset>(
5753        &self,
5754        range: Range<T>,
5755    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5756    {
5757        let range = range.start.to_offset(self)..range.end.to_offset(self);
5758        let mut excerpt = self.excerpt_containing(range.clone())?;
5759        Some(
5760            excerpt
5761                .buffer()
5762                .bracket_ranges(excerpt.map_range_to_buffer(range))
5763                .filter_map(move |pair| {
5764                    let open_range =
5765                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5766                    let close_range =
5767                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5768                    excerpt
5769                        .contains_buffer_range(open_range.start..close_range.end)
5770                        .then(|| BracketMatch {
5771                            open_range: excerpt.map_range_from_buffer(open_range),
5772                            close_range: excerpt.map_range_from_buffer(close_range),
5773                            color_index: pair.color_index,
5774                            newline_only: pair.newline_only,
5775                            syntax_layer_depth: pair.syntax_layer_depth,
5776                        })
5777                })
5778                .map(BracketMatch::bracket_ranges),
5779        )
5780    }
5781
5782    pub fn redacted_ranges<'a, T: ToOffset>(
5783        &'a self,
5784        range: Range<T>,
5785        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5786    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5787        let range = range.start.to_offset(self)..range.end.to_offset(self);
5788        self.lift_buffer_metadata(range, move |buffer, range| {
5789            if redaction_enabled(buffer.file()) {
5790                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5791            } else {
5792                None
5793            }
5794        })
5795        .map(|(range, _, _)| range)
5796    }
5797
5798    pub fn runnable_ranges(
5799        &self,
5800        range: Range<Anchor>,
5801    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5802        let range = range.start.to_offset(self)..range.end.to_offset(self);
5803        self.lift_buffer_metadata(range, move |buffer, range| {
5804            Some(
5805                buffer
5806                    .runnable_ranges(range.clone())
5807                    .filter(move |runnable| {
5808                        runnable.run_range.start >= range.start
5809                            && runnable.run_range.end < range.end
5810                    })
5811                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5812            )
5813        })
5814        .map(|(run_range, runnable, _)| (run_range, runnable))
5815    }
5816
5817    pub fn line_indents(
5818        &self,
5819        start_row: MultiBufferRow,
5820        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5821    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5822        let max_point = self.max_point();
5823        let mut cursor = self.cursor::<Point, Point>();
5824        cursor.seek(&Point::new(start_row.0, 0));
5825        iter::from_fn(move || {
5826            let mut region = cursor.region()?;
5827            while !buffer_filter(&region.excerpt.buffer) {
5828                cursor.next();
5829                region = cursor.region()?;
5830            }
5831            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5832            let buffer_start_row =
5833                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5834
5835            let buffer_end_row = if region.is_main_buffer
5836                && (region.has_trailing_newline || region.range.end == max_point)
5837            {
5838                region.buffer_range.end.row
5839            } else {
5840                region.buffer_range.end.row.saturating_sub(1)
5841            };
5842
5843            let line_indents = region
5844                .buffer
5845                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5846            cursor.next();
5847            Some(line_indents.map(move |(buffer_row, indent)| {
5848                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5849                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5850            }))
5851        })
5852        .flatten()
5853    }
5854
5855    pub fn reversed_line_indents(
5856        &self,
5857        end_row: MultiBufferRow,
5858        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5859    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5860        let max_point = self.max_point();
5861        let mut cursor = self.cursor::<Point, Point>();
5862        cursor.seek(&Point::new(end_row.0, 0));
5863        iter::from_fn(move || {
5864            let mut region = cursor.region()?;
5865            while !buffer_filter(&region.excerpt.buffer) {
5866                cursor.prev();
5867                region = cursor.region()?;
5868            }
5869
5870            let buffer_start_row = region.buffer_range.start.row;
5871            let buffer_end_row = if region.is_main_buffer
5872                && (region.has_trailing_newline || region.range.end == max_point)
5873            {
5874                region.buffer_range.end.row + 1
5875            } else {
5876                region.buffer_range.end.row
5877            };
5878
5879            let overshoot = end_row.0 - region.range.start.row;
5880            let buffer_end_row =
5881                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5882
5883            let line_indents = region
5884                .buffer
5885                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5886            cursor.prev();
5887            Some(line_indents.map(move |(buffer_row, indent)| {
5888                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5889                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5890            }))
5891        })
5892        .flatten()
5893    }
5894
5895    pub async fn enclosing_indent(
5896        &self,
5897        mut target_row: MultiBufferRow,
5898    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5899        let max_row = MultiBufferRow(self.max_point().row);
5900        if target_row >= max_row {
5901            return None;
5902        }
5903
5904        let mut target_indent = self.line_indent_for_row(target_row);
5905
5906        // If the current row is at the start of an indented block, we want to return this
5907        // block as the enclosing indent.
5908        if !target_indent.is_line_empty() && target_row < max_row {
5909            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5910            if !next_line_indent.is_line_empty()
5911                && target_indent.raw_len() < next_line_indent.raw_len()
5912            {
5913                target_indent = next_line_indent;
5914                target_row.0 += 1;
5915            }
5916        }
5917
5918        const SEARCH_ROW_LIMIT: u32 = 25000;
5919        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5920        const YIELD_INTERVAL: u32 = 100;
5921
5922        let mut accessed_row_counter = 0;
5923
5924        // If there is a blank line at the current row, search for the next non indented lines
5925        if target_indent.is_line_empty() {
5926            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5927            let end =
5928                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5929
5930            let mut non_empty_line_above = None;
5931            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5932                if row < start {
5933                    break;
5934                }
5935                accessed_row_counter += 1;
5936                if accessed_row_counter == YIELD_INTERVAL {
5937                    accessed_row_counter = 0;
5938                    yield_now().await;
5939                }
5940                if !indent.is_line_empty() {
5941                    non_empty_line_above = Some((row, indent));
5942                    break;
5943                }
5944            }
5945
5946            let mut non_empty_line_below = None;
5947            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5948                if row > end {
5949                    break;
5950                }
5951                accessed_row_counter += 1;
5952                if accessed_row_counter == YIELD_INTERVAL {
5953                    accessed_row_counter = 0;
5954                    yield_now().await;
5955                }
5956                if !indent.is_line_empty() {
5957                    non_empty_line_below = Some((row, indent));
5958                    break;
5959                }
5960            }
5961
5962            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5963                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5964                    if above_indent.raw_len() >= below_indent.raw_len() {
5965                        (above_row, above_indent)
5966                    } else {
5967                        (below_row, below_indent)
5968                    }
5969                }
5970                (Some(above), None) => above,
5971                (None, Some(below)) => below,
5972                _ => return None,
5973            };
5974
5975            target_indent = indent;
5976            target_row = row;
5977        }
5978
5979        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5980        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5981
5982        let mut start_indent = None;
5983        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5984            if row < start {
5985                break;
5986            }
5987            accessed_row_counter += 1;
5988            if accessed_row_counter == YIELD_INTERVAL {
5989                accessed_row_counter = 0;
5990                yield_now().await;
5991            }
5992            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5993                start_indent = Some((row, indent));
5994                break;
5995            }
5996        }
5997        let (start_row, start_indent_size) = start_indent?;
5998
5999        let mut end_indent = (end, None);
6000        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6001            if row > end {
6002                break;
6003            }
6004            accessed_row_counter += 1;
6005            if accessed_row_counter == YIELD_INTERVAL {
6006                accessed_row_counter = 0;
6007                yield_now().await;
6008            }
6009            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6010                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6011                break;
6012            }
6013        }
6014        let (end_row, end_indent_size) = end_indent;
6015
6016        let indent = if let Some(end_indent_size) = end_indent_size {
6017            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6018                start_indent_size
6019            } else {
6020                end_indent_size
6021            }
6022        } else {
6023            start_indent_size
6024        };
6025
6026        Some((start_row..end_row, indent))
6027    }
6028
6029    pub fn indent_guides_in_range<T: ToPoint>(
6030        &self,
6031        range: Range<T>,
6032        ignore_disabled_for_language: bool,
6033        cx: &App,
6034    ) -> impl Iterator<Item = IndentGuide> {
6035        let range = range.start.to_point(self)..range.end.to_point(self);
6036        let start_row = MultiBufferRow(range.start.row);
6037        let end_row = MultiBufferRow(range.end.row);
6038
6039        let mut row_indents = self.line_indents(start_row, |buffer| {
6040            let settings =
6041                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6042            settings.indent_guides.enabled || ignore_disabled_for_language
6043        });
6044
6045        let mut result = Vec::new();
6046        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6047
6048        let mut prev_settings = None;
6049        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6050            if first_row > end_row {
6051                break;
6052            }
6053            let current_depth = indent_stack.len() as u32;
6054
6055            // Avoid retrieving the language settings repeatedly for every buffer row.
6056            if let Some((prev_buffer_id, _)) = &prev_settings
6057                && prev_buffer_id != &buffer.remote_id()
6058            {
6059                prev_settings.take();
6060            }
6061            let settings = &prev_settings
6062                .get_or_insert_with(|| {
6063                    (
6064                        buffer.remote_id(),
6065                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6066                    )
6067                })
6068                .1;
6069            let tab_size = settings.tab_size.get();
6070
6071            // When encountering empty, continue until found useful line indent
6072            // then add to the indent stack with the depth found
6073            let mut found_indent = false;
6074            let mut last_row = first_row;
6075            if line_indent.is_line_blank() {
6076                while !found_indent {
6077                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6078                        break;
6079                    };
6080                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6081                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6082                        break;
6083                    }
6084
6085                    if new_line_indent.is_line_blank() {
6086                        continue;
6087                    }
6088                    last_row = target_row.min(end_row);
6089                    line_indent = new_line_indent;
6090                    found_indent = true;
6091                    break;
6092                }
6093            } else {
6094                found_indent = true
6095            }
6096
6097            let depth = if found_indent {
6098                line_indent.len(tab_size) / tab_size
6099            } else {
6100                0
6101            };
6102
6103            match depth.cmp(&current_depth) {
6104                cmp::Ordering::Less => {
6105                    for _ in 0..(current_depth - depth) {
6106                        let mut indent = indent_stack.pop().unwrap();
6107                        if last_row != first_row {
6108                            // In this case, we landed on an empty row, had to seek forward,
6109                            // and discovered that the indent we where on is ending.
6110                            // This means that the last display row must
6111                            // be on line that ends this indent range, so we
6112                            // should display the range up to the first non-empty line
6113                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6114                        }
6115
6116                        result.push(indent)
6117                    }
6118                }
6119                cmp::Ordering::Greater => {
6120                    for next_depth in current_depth..depth {
6121                        indent_stack.push(IndentGuide {
6122                            buffer_id: buffer.remote_id(),
6123                            start_row: first_row,
6124                            end_row: last_row,
6125                            depth: next_depth,
6126                            tab_size,
6127                            settings: settings.indent_guides.clone(),
6128                        });
6129                    }
6130                }
6131                _ => {}
6132            }
6133
6134            for indent in indent_stack.iter_mut() {
6135                indent.end_row = last_row;
6136            }
6137        }
6138
6139        result.extend(indent_stack);
6140        result.into_iter()
6141    }
6142
6143    pub fn trailing_excerpt_update_count(&self) -> usize {
6144        self.trailing_excerpt_update_count
6145    }
6146
6147    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6148        self.point_to_buffer_offset(point)
6149            .and_then(|(buffer, _)| buffer.file())
6150    }
6151
6152    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6153        self.point_to_buffer_offset(offset)
6154            .and_then(|(buffer, offset)| buffer.language_at(offset))
6155    }
6156
6157    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6158        self.excerpts
6159            .first()
6160            .map(|excerpt| &excerpt.buffer)
6161            .map(|buffer| {
6162                language_settings(
6163                    buffer.language().map(|language| language.name()),
6164                    buffer.file(),
6165                    cx,
6166                )
6167            })
6168            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6169    }
6170
6171    pub fn language_settings_at<'a, T: ToOffset>(
6172        &'a self,
6173        point: T,
6174        cx: &'a App,
6175    ) -> Cow<'a, LanguageSettings> {
6176        let mut language = None;
6177        let mut file = None;
6178        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6179            language = buffer.language_at(offset);
6180            file = buffer.file();
6181        }
6182        language_settings(language.map(|l| l.name()), file, cx)
6183    }
6184
6185    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6186        self.point_to_buffer_offset(point)
6187            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6188    }
6189
6190    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6191        self.point_to_buffer_offset(point)
6192            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6193            .unwrap_or_default()
6194    }
6195
6196    pub fn language_indent_size_at<T: ToOffset>(
6197        &self,
6198        position: T,
6199        cx: &App,
6200    ) -> Option<IndentSize> {
6201        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6202        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6203    }
6204
6205    pub fn is_dirty(&self) -> bool {
6206        self.is_dirty
6207    }
6208
6209    pub fn has_deleted_file(&self) -> bool {
6210        self.has_deleted_file
6211    }
6212
6213    pub fn has_conflict(&self) -> bool {
6214        self.has_conflict
6215    }
6216
6217    pub fn has_diagnostics(&self) -> bool {
6218        self.excerpts
6219            .iter()
6220            .any(|excerpt| excerpt.buffer.has_diagnostics())
6221    }
6222
6223    pub fn diagnostic_group(
6224        &self,
6225        buffer_id: BufferId,
6226        group_id: usize,
6227    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6228        self.lift_buffer_metadata::<Point, _, _>(
6229            Point::zero()..self.max_point(),
6230            move |buffer, range| {
6231                if buffer.remote_id() != buffer_id {
6232                    return None;
6233                };
6234                Some(
6235                    buffer
6236                        .diagnostics_in_range(range, false)
6237                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6238                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6239                )
6240            },
6241        )
6242        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6243    }
6244
6245    pub fn diagnostics_in_range<'a, MBD>(
6246        &'a self,
6247        range: Range<MBD>,
6248    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6249    where
6250        MBD::TextDimension: 'a
6251            + text::ToOffset
6252            + text::FromAnchor
6253            + Sub<Output = MBD::TextDimension>
6254            + fmt::Debug
6255            + ops::Add<Output = MBD::TextDimension>
6256            + ops::AddAssign
6257            + Ord,
6258        MBD: MultiBufferDimension
6259            + Ord
6260            + Sub<Output = MBD::TextDimension>
6261            + ops::Add<MBD::TextDimension, Output = MBD>
6262            + ops::AddAssign<MBD::TextDimension>
6263            + 'a,
6264    {
6265        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6266            Some(
6267                buffer
6268                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6269                    .map(|entry| (entry.range, entry.diagnostic)),
6270            )
6271        })
6272        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6273    }
6274
6275    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6276        &'a self,
6277        range: Range<MBD>,
6278    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6279    where
6280        MBD: MultiBufferDimension
6281            + Ord
6282            + Sub<Output = MBD::TextDimension>
6283            + ops::Add<MBD::TextDimension, Output = MBD>
6284            + ops::AddAssign<MBD::TextDimension>,
6285        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6286            + ops::Add<Output = MBD::TextDimension>
6287            + text::ToOffset
6288            + text::FromAnchor
6289            + AddAssign<MBD::TextDimension>
6290            + Ord,
6291    {
6292        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6293            Some(
6294                buffer
6295                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6296                    .map(|entry| (entry.range, entry.diagnostic)),
6297            )
6298        })
6299        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6300    }
6301
6302    pub fn syntax_ancestor<T: ToOffset>(
6303        &self,
6304        range: Range<T>,
6305    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6306        let range = range.start.to_offset(self)..range.end.to_offset(self);
6307        let mut excerpt = self.excerpt_containing(range.clone())?;
6308        let node = excerpt
6309            .buffer()
6310            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6311        let node_range = node.byte_range();
6312        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6313        if !excerpt.contains_buffer_range(node_range.clone()) {
6314            return None;
6315        };
6316        Some((node, excerpt.map_range_from_buffer(node_range)))
6317    }
6318
6319    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6320        let (excerpt_id, _, buffer) = self.as_singleton()?;
6321        let outline = buffer.outline(theme);
6322        Some(Outline::new(
6323            outline
6324                .items
6325                .into_iter()
6326                .flat_map(|item| {
6327                    Some(OutlineItem {
6328                        depth: item.depth,
6329                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6330                        source_range_for_text: self
6331                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6332                        text: item.text,
6333                        highlight_ranges: item.highlight_ranges,
6334                        name_ranges: item.name_ranges,
6335                        body_range: item.body_range.and_then(|body_range| {
6336                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6337                        }),
6338                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6339                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6340                        }),
6341                    })
6342                })
6343                .collect(),
6344        ))
6345    }
6346
6347    pub fn symbols_containing<T: ToOffset>(
6348        &self,
6349        offset: T,
6350        theme: Option<&SyntaxTheme>,
6351    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6352        let anchor = self.anchor_before(offset);
6353        let excerpt @ &Excerpt {
6354            id: excerpt_id,
6355            buffer_id,
6356            ref buffer,
6357            ..
6358        } = self.excerpt(anchor.excerpt_id)?;
6359        if cfg!(debug_assertions) {
6360            match anchor.text_anchor.buffer_id {
6361                // we clearly are hitting this according to sentry, but in what situations can this occur?
6362                Some(anchor_buffer_id) => {
6363                    assert_eq!(
6364                        anchor_buffer_id, buffer_id,
6365                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6366                    )
6367                }
6368                None => assert!(anchor.is_max()),
6369            }
6370        };
6371        Some((
6372            buffer_id,
6373            buffer
6374                .symbols_containing(anchor.text_anchor, theme)
6375                .into_iter()
6376                .flat_map(|item| {
6377                    Some(OutlineItem {
6378                        depth: item.depth,
6379                        source_range_for_text: Anchor::range_in_buffer(
6380                            excerpt_id,
6381                            item.source_range_for_text,
6382                        ),
6383                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6384                        text: item.text,
6385                        highlight_ranges: item.highlight_ranges,
6386                        name_ranges: item.name_ranges,
6387                        body_range: item
6388                            .body_range
6389                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6390                        annotation_range: item
6391                            .annotation_range
6392                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6393                    })
6394                })
6395                .collect(),
6396        ))
6397    }
6398
6399    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6400        if id == ExcerptId::min() {
6401            Locator::min_ref()
6402        } else if id == ExcerptId::max() {
6403            Locator::max_ref()
6404        } else {
6405            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6406            if let Some(entry) = item
6407                && entry.id == id
6408            {
6409                return &entry.locator;
6410            }
6411            panic!("invalid excerpt id {id:?}")
6412        }
6413    }
6414
6415    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6416    fn excerpt_locators_for_ids(
6417        &self,
6418        ids: impl IntoIterator<Item = ExcerptId>,
6419    ) -> SmallVec<[Locator; 1]> {
6420        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6421        sorted_ids.sort_unstable();
6422        sorted_ids.dedup();
6423        let mut locators = SmallVec::new();
6424
6425        while sorted_ids.last() == Some(&ExcerptId::max()) {
6426            sorted_ids.pop();
6427            locators.push(Locator::max());
6428        }
6429
6430        let mut sorted_ids = sorted_ids.into_iter().peekable();
6431        locators.extend(
6432            sorted_ids
6433                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6434                .map(|_| Locator::min()),
6435        );
6436
6437        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6438        for id in sorted_ids {
6439            if cursor.seek_forward(&id, Bias::Left) {
6440                locators.push(cursor.item().unwrap().locator.clone());
6441            } else {
6442                panic!("invalid excerpt id {:?}", id);
6443            }
6444        }
6445
6446        locators.sort_unstable();
6447        locators
6448    }
6449
6450    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6451        Some(self.excerpt(excerpt_id)?.buffer_id)
6452    }
6453
6454    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6455        Some(&self.excerpt(excerpt_id)?.buffer)
6456    }
6457
6458    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6459        let mut cursor = self
6460            .excerpts
6461            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6462        let locator = self.excerpt_locator_for_id(excerpt_id);
6463        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6464        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6465            sought_exact = true;
6466            cursor.prev();
6467        } else if excerpt_id == ExcerptId::min() {
6468            sought_exact = true;
6469        }
6470        if sought_exact {
6471            let start = cursor.start().1;
6472            let end = cursor.end().1;
6473            let mut diff_transforms = self
6474                .diff_transforms
6475                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6476            diff_transforms.seek(&start, Bias::Left);
6477            let overshoot = start - diff_transforms.start().0;
6478            let start = diff_transforms.start().1 + overshoot;
6479            diff_transforms.seek(&end, Bias::Right);
6480            let overshoot = end - diff_transforms.start().0;
6481            let end = diff_transforms.start().1 + overshoot;
6482            Some(start.0..end.0)
6483        } else {
6484            None
6485        }
6486    }
6487
6488    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6489    /// to have the same excerpt id as the one passed in, with the exception of
6490    /// `ExcerptId::max()`.
6491    ///
6492    /// Callers of this function should generally use the resulting excerpt's `id` field
6493    /// afterwards.
6494    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6495        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6496        let locator = self.excerpt_locator_for_id(excerpt_id);
6497        cursor.seek(&Some(locator), Bias::Left);
6498        if let Some(excerpt) = cursor.item()
6499            && excerpt.id == excerpt_id
6500        {
6501            return Some(excerpt);
6502        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6503            cursor.prev();
6504            return cursor.item();
6505        }
6506        None
6507    }
6508
6509    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6510    pub fn excerpt_containing<T: ToOffset>(
6511        &self,
6512        range: Range<T>,
6513    ) -> Option<MultiBufferExcerpt<'_>> {
6514        let range = range.start.to_offset(self)..range.end.to_offset(self);
6515        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6516        cursor.seek(&range.start);
6517
6518        let start_excerpt = cursor.excerpt()?;
6519        if range.end != range.start {
6520            cursor.seek_forward(&range.end);
6521            if cursor.excerpt()?.id != start_excerpt.id {
6522                return None;
6523            }
6524        }
6525
6526        cursor.seek_to_start_of_current_excerpt();
6527        let region = cursor.region()?;
6528        let offset = region.range.start;
6529        let buffer_offset = start_excerpt.buffer_start_offset();
6530        let excerpt_offset = *cursor.excerpts.start();
6531        Some(MultiBufferExcerpt {
6532            diff_transforms: cursor.diff_transforms,
6533            excerpt: start_excerpt,
6534            offset,
6535            buffer_offset,
6536            excerpt_offset,
6537        })
6538    }
6539
6540    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6541        if let Some(id) = anchor.text_anchor.buffer_id {
6542            return Some(id);
6543        }
6544        let excerpt = self.excerpt_containing(anchor..anchor)?;
6545        Some(excerpt.buffer_id())
6546    }
6547
6548    pub fn selections_in_range<'a>(
6549        &'a self,
6550        range: &'a Range<Anchor>,
6551        include_local: bool,
6552    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6553        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6554        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6555        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6556        cursor.seek(start_locator, Bias::Left);
6557        cursor
6558            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6559            .flat_map(move |excerpt| {
6560                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6561                if excerpt.id == range.start.excerpt_id {
6562                    query_range.start = range.start.text_anchor;
6563                }
6564                if excerpt.id == range.end.excerpt_id {
6565                    query_range.end = range.end.text_anchor;
6566                }
6567
6568                excerpt
6569                    .buffer
6570                    .selections_in_range(query_range, include_local)
6571                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6572                        selections.map(move |selection| {
6573                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6574                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6575                            if range.start.cmp(&start, self).is_gt() {
6576                                start = range.start;
6577                            }
6578                            if range.end.cmp(&end, self).is_lt() {
6579                                end = range.end;
6580                            }
6581
6582                            (
6583                                replica_id,
6584                                line_mode,
6585                                cursor_shape,
6586                                Selection {
6587                                    id: selection.id,
6588                                    start,
6589                                    end,
6590                                    reversed: selection.reversed,
6591                                    goal: selection.goal,
6592                                },
6593                            )
6594                        })
6595                    })
6596            })
6597    }
6598
6599    pub fn show_headers(&self) -> bool {
6600        self.show_headers
6601    }
6602
6603    /// Visually annotates a position or range with the `Debug` representation of a value. The
6604    /// callsite of this function is used as a key - previous annotations will be removed.
6605    #[cfg(debug_assertions)]
6606    #[track_caller]
6607    pub fn debug<V, R>(&self, ranges: &R, value: V)
6608    where
6609        R: debug::ToMultiBufferDebugRanges,
6610        V: std::fmt::Debug,
6611    {
6612        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6613    }
6614
6615    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6616    /// debug annotations with the same key will be removed. The key is also used to determine the
6617    /// annotation's color.
6618    #[cfg(debug_assertions)]
6619    #[track_caller]
6620    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6621    where
6622        K: std::hash::Hash + 'static,
6623        R: debug::ToMultiBufferDebugRanges,
6624        V: std::fmt::Debug,
6625    {
6626        let text_ranges = ranges
6627            .to_multi_buffer_debug_ranges(self)
6628            .into_iter()
6629            .flat_map(|range| {
6630                self.range_to_buffer_ranges(range).into_iter().map(
6631                    |(buffer, range, _excerpt_id)| {
6632                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6633                    },
6634                )
6635            })
6636            .collect();
6637        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6638            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6639        });
6640    }
6641}
6642
6643#[cfg(any(test, feature = "test-support"))]
6644impl MultiBufferSnapshot {
6645    pub fn random_byte_range(
6646        &self,
6647        start_offset: MultiBufferOffset,
6648        rng: &mut impl rand::Rng,
6649    ) -> Range<MultiBufferOffset> {
6650        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6651        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6652        start..end
6653    }
6654
6655    #[cfg(any(test, feature = "test-support"))]
6656    fn check_invariants(&self) {
6657        let excerpts = self.excerpts.items(());
6658        let excerpt_ids = self.excerpt_ids.items(());
6659
6660        for (ix, excerpt) in excerpts.iter().enumerate() {
6661            if ix == 0 {
6662                if excerpt.locator <= Locator::min() {
6663                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6664                }
6665            } else if excerpt.locator <= excerpts[ix - 1].locator {
6666                panic!("excerpts are out-of-order: {:?}", excerpts);
6667            }
6668        }
6669
6670        for (ix, entry) in excerpt_ids.iter().enumerate() {
6671            if ix == 0 {
6672                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6673                    panic!("invalid first excerpt id {:?}", entry.id);
6674                }
6675            } else if entry.id <= excerpt_ids[ix - 1].id {
6676                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6677            }
6678        }
6679
6680        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6681            panic!(
6682                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6683                self.excerpts.summary().text,
6684                self.diff_transforms.summary().input,
6685                self.diff_transforms.items(()),
6686            );
6687        }
6688
6689        let mut prev_transform: Option<&DiffTransform> = None;
6690        for item in self.diff_transforms.iter() {
6691            if let DiffTransform::BufferContent {
6692                summary,
6693                inserted_hunk_info,
6694            } = item
6695            {
6696                if let Some(DiffTransform::BufferContent {
6697                    inserted_hunk_info: prev_inserted_hunk_info,
6698                    ..
6699                }) = prev_transform
6700                    && *inserted_hunk_info == *prev_inserted_hunk_info
6701                {
6702                    panic!(
6703                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6704                        self.diff_transforms.items(())
6705                    );
6706                }
6707                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6708                    panic!("empty buffer content transform");
6709                }
6710            }
6711            prev_transform = Some(item);
6712        }
6713    }
6714}
6715
6716impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6717where
6718    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6719    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6720{
6721    fn seek(&mut self, position: &MBD) {
6722        let position = OutputDimension(*position);
6723        self.cached_region.take();
6724        self.diff_transforms.seek(&position, Bias::Right);
6725        if self.diff_transforms.item().is_none()
6726            && self.diff_transforms.start().output_dimension == position
6727        {
6728            self.diff_transforms.prev();
6729        }
6730
6731        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6732        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6733            let overshoot = position - self.diff_transforms.start().output_dimension;
6734            excerpt_position += overshoot;
6735        }
6736
6737        self.excerpts.seek(&excerpt_position, Bias::Right);
6738        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6739            self.excerpts.prev();
6740        }
6741    }
6742
6743    fn seek_forward(&mut self, position: &MBD) {
6744        let position = OutputDimension(*position);
6745        self.cached_region.take();
6746        self.diff_transforms.seek_forward(&position, Bias::Right);
6747        if self.diff_transforms.item().is_none()
6748            && self.diff_transforms.start().output_dimension == position
6749        {
6750            self.diff_transforms.prev();
6751        }
6752
6753        let overshoot = position - self.diff_transforms.start().output_dimension;
6754        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6755        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6756            excerpt_position += overshoot;
6757        }
6758
6759        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6760        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6761            self.excerpts.prev();
6762        }
6763    }
6764
6765    fn next_excerpt(&mut self) {
6766        self.excerpts.next();
6767        self.seek_to_start_of_current_excerpt();
6768    }
6769
6770    fn prev_excerpt(&mut self) {
6771        self.excerpts.prev();
6772        self.seek_to_start_of_current_excerpt();
6773    }
6774
6775    fn seek_to_start_of_current_excerpt(&mut self) {
6776        self.cached_region.take();
6777        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6778        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6779            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6780            && self.diff_transforms.next_item().is_some()
6781        {
6782            self.diff_transforms.next();
6783        }
6784    }
6785
6786    fn next(&mut self) {
6787        self.cached_region.take();
6788        match self
6789            .diff_transforms
6790            .end()
6791            .excerpt_dimension
6792            .cmp(&self.excerpts.end())
6793        {
6794            cmp::Ordering::Less => self.diff_transforms.next(),
6795            cmp::Ordering::Greater => self.excerpts.next(),
6796            cmp::Ordering::Equal => {
6797                self.diff_transforms.next();
6798                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6799                    || self.diff_transforms.item().is_none()
6800                {
6801                    self.excerpts.next();
6802                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6803                    self.diff_transforms.item()
6804                    && self
6805                        .excerpts
6806                        .item()
6807                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6808                {
6809                    self.excerpts.next();
6810                }
6811            }
6812        }
6813    }
6814
6815    fn prev(&mut self) {
6816        self.cached_region.take();
6817        match self
6818            .diff_transforms
6819            .start()
6820            .excerpt_dimension
6821            .cmp(self.excerpts.start())
6822        {
6823            cmp::Ordering::Less => self.excerpts.prev(),
6824            cmp::Ordering::Greater => self.diff_transforms.prev(),
6825            cmp::Ordering::Equal => {
6826                self.diff_transforms.prev();
6827                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6828                    || self.diff_transforms.item().is_none()
6829                {
6830                    self.excerpts.prev();
6831                }
6832            }
6833        }
6834    }
6835
6836    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6837        if self.cached_region.is_none() {
6838            self.cached_region = self.build_region();
6839        }
6840        self.cached_region.clone()
6841    }
6842
6843    fn is_at_start_of_excerpt(&mut self) -> bool {
6844        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6845            return false;
6846        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6847            return true;
6848        }
6849
6850        self.diff_transforms.prev();
6851        let prev_transform = self.diff_transforms.item();
6852        self.diff_transforms.next();
6853
6854        prev_transform.is_none_or(|next_transform| {
6855            matches!(next_transform, DiffTransform::BufferContent { .. })
6856        })
6857    }
6858
6859    fn is_at_end_of_excerpt(&mut self) -> bool {
6860        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6861            return false;
6862        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6863            || self.diff_transforms.item().is_none()
6864        {
6865            return true;
6866        }
6867
6868        let next_transform = self.diff_transforms.next_item();
6869        next_transform.is_none_or(|next_transform| match next_transform {
6870            DiffTransform::BufferContent { .. } => true,
6871            DiffTransform::DeletedHunk { hunk_info, .. } => self
6872                .excerpts
6873                .item()
6874                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6875        })
6876    }
6877
6878    fn main_buffer_position(&self) -> Option<BD> {
6879        let excerpt = self.excerpts.item()?;
6880        let buffer = &excerpt.buffer;
6881        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6882        let mut buffer_start = buffer_context_start;
6883        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6884        buffer_start += overshoot;
6885        Some(buffer_start)
6886    }
6887
6888    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6889        let excerpt = self.excerpts.item()?;
6890        match self.diff_transforms.item()? {
6891            DiffTransform::DeletedHunk {
6892                buffer_id,
6893                base_text_byte_range,
6894                has_trailing_newline,
6895                hunk_info,
6896                ..
6897            } => {
6898                let diff = self.diffs.get(buffer_id)?;
6899                let buffer = diff.base_text();
6900                let mut rope_cursor = buffer.as_rope().cursor(0);
6901                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6902                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6903                let mut buffer_end = buffer_start;
6904                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6905                let start = self.diff_transforms.start().output_dimension.0;
6906                let end = self.diff_transforms.end().output_dimension.0;
6907                Some(MultiBufferRegion {
6908                    buffer,
6909                    excerpt,
6910                    has_trailing_newline: *has_trailing_newline,
6911                    is_main_buffer: false,
6912                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6913                        hunk_info.hunk_secondary_status,
6914                    )),
6915                    buffer_range: buffer_start..buffer_end,
6916                    range: start..end,
6917                })
6918            }
6919            DiffTransform::BufferContent {
6920                inserted_hunk_info, ..
6921            } => {
6922                let buffer = &excerpt.buffer;
6923                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6924
6925                let mut start = self.diff_transforms.start().output_dimension.0;
6926                let mut buffer_start = buffer_context_start;
6927                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6928                    let overshoot =
6929                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6930                    start += overshoot;
6931                } else {
6932                    let overshoot =
6933                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6934                    buffer_start += overshoot;
6935                }
6936
6937                let mut end;
6938                let mut buffer_end;
6939                let has_trailing_newline;
6940                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6941                    let overshoot =
6942                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6943                    end = self.diff_transforms.end().output_dimension.0;
6944                    buffer_end = buffer_context_start;
6945                    buffer_end += overshoot;
6946                    has_trailing_newline = false;
6947                } else {
6948                    let overshoot =
6949                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6950                    end = self.diff_transforms.start().output_dimension.0;
6951                    end += overshoot;
6952                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6953                    has_trailing_newline = excerpt.has_trailing_newline;
6954                };
6955
6956                let diff_hunk_status = inserted_hunk_info.map(|info| {
6957                    if info.is_logically_deleted {
6958                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6959                    } else {
6960                        DiffHunkStatus::added(info.hunk_secondary_status)
6961                    }
6962                });
6963
6964                Some(MultiBufferRegion {
6965                    buffer,
6966                    excerpt,
6967                    has_trailing_newline,
6968                    is_main_buffer: true,
6969                    diff_hunk_status,
6970                    buffer_range: buffer_start..buffer_end,
6971                    range: start..end,
6972                })
6973            }
6974        }
6975    }
6976
6977    fn excerpt(&self) -> Option<&'a Excerpt> {
6978        self.excerpts.item()
6979    }
6980}
6981
6982impl Excerpt {
6983    fn new(
6984        id: ExcerptId,
6985        locator: Locator,
6986        buffer_id: BufferId,
6987        buffer: BufferSnapshot,
6988        range: ExcerptRange<text::Anchor>,
6989        has_trailing_newline: bool,
6990    ) -> Self {
6991        Excerpt {
6992            id,
6993            locator,
6994            max_buffer_row: range.context.end.to_point(&buffer).row,
6995            text_summary: buffer
6996                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6997            buffer_id,
6998            buffer,
6999            range,
7000            has_trailing_newline,
7001        }
7002    }
7003
7004    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7005        let content_start = self.range.context.start.to_offset(&self.buffer);
7006        let chunks_start = content_start + range.start;
7007        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7008
7009        let has_footer = self.has_trailing_newline
7010            && range.start <= self.text_summary.len
7011            && range.end > self.text_summary.len;
7012
7013        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7014
7015        ExcerptChunks {
7016            excerpt_id: self.id,
7017            content_chunks,
7018            has_footer,
7019        }
7020    }
7021
7022    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7023        let content_start = self.range.context.start.to_offset(&self.buffer);
7024        let chunks_start = content_start + range.start;
7025        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7026        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7027        excerpt_chunks.has_footer = self.has_trailing_newline
7028            && range.start <= self.text_summary.len
7029            && range.end > self.text_summary.len;
7030    }
7031
7032    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7033        if text_anchor
7034            .cmp(&self.range.context.start, &self.buffer)
7035            .is_lt()
7036        {
7037            self.range.context.start
7038        } else if text_anchor
7039            .cmp(&self.range.context.end, &self.buffer)
7040            .is_gt()
7041        {
7042            self.range.context.end
7043        } else {
7044            text_anchor
7045        }
7046    }
7047
7048    fn contains(&self, anchor: &Anchor) -> bool {
7049        (anchor.text_anchor.buffer_id == None
7050            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7051            && self
7052                .range
7053                .context
7054                .start
7055                .cmp(&anchor.text_anchor, &self.buffer)
7056                .is_le()
7057            && self
7058                .range
7059                .context
7060                .end
7061                .cmp(&anchor.text_anchor, &self.buffer)
7062                .is_ge()
7063    }
7064
7065    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7066    fn buffer_start_offset(&self) -> BufferOffset {
7067        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7068    }
7069
7070    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7071    fn buffer_end_offset(&self) -> BufferOffset {
7072        self.buffer_start_offset() + self.text_summary.len
7073    }
7074}
7075
7076impl<'a> MultiBufferExcerpt<'a> {
7077    pub fn id(&self) -> ExcerptId {
7078        self.excerpt.id
7079    }
7080
7081    pub fn buffer_id(&self) -> BufferId {
7082        self.excerpt.buffer_id
7083    }
7084
7085    pub fn start_anchor(&self) -> Anchor {
7086        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7087    }
7088
7089    pub fn end_anchor(&self) -> Anchor {
7090        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7091    }
7092
7093    pub fn buffer(&self) -> &'a BufferSnapshot {
7094        &self.excerpt.buffer
7095    }
7096
7097    pub fn buffer_range(&self) -> Range<BufferOffset> {
7098        self.buffer_offset
7099            ..BufferOffset(
7100                self.excerpt
7101                    .range
7102                    .context
7103                    .end
7104                    .to_offset(&self.excerpt.buffer.text),
7105            )
7106    }
7107
7108    pub fn start_offset(&self) -> MultiBufferOffset {
7109        self.offset
7110    }
7111
7112    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7113    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7114        self.map_range_to_buffer(offset..offset).start
7115    }
7116
7117    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7118    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7119        self.diff_transforms
7120            .seek(&OutputDimension(range.start), Bias::Right);
7121        let start = self.map_offset_to_buffer_internal(range.start);
7122        let end = if range.end > range.start {
7123            self.diff_transforms
7124                .seek_forward(&OutputDimension(range.end), Bias::Right);
7125            self.map_offset_to_buffer_internal(range.end)
7126        } else {
7127            start
7128        };
7129        start..end
7130    }
7131
7132    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7133        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7134        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7135            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7136        };
7137        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7138        self.buffer_offset + offset_in_excerpt
7139    }
7140
7141    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7142    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7143        self.map_range_from_buffer(buffer_offset..buffer_offset)
7144            .start
7145    }
7146
7147    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7148    pub fn map_range_from_buffer(
7149        &mut self,
7150        buffer_range: Range<BufferOffset>,
7151    ) -> Range<MultiBufferOffset> {
7152        if buffer_range.start < self.buffer_offset {
7153            log::warn!(
7154                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7155            );
7156            return self.offset..self.offset;
7157        }
7158        let overshoot = buffer_range.start - self.buffer_offset;
7159        let excerpt_offset = self.excerpt_offset + overshoot;
7160        let excerpt_seek_dim = excerpt_offset;
7161        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7162        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7163            log::warn!(
7164                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7165            );
7166            return self.offset..self.offset;
7167        }
7168        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7169        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7170
7171        let end = if buffer_range.start < buffer_range.end {
7172            let overshoot = buffer_range.end - self.buffer_offset;
7173            let excerpt_offset = self.excerpt_offset + overshoot;
7174            let excerpt_seek_dim = excerpt_offset;
7175            self.diff_transforms
7176                .seek_forward(&excerpt_seek_dim, Bias::Right);
7177            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7178            // todo(lw): Clamp end to the excerpt boundaries
7179            self.diff_transforms.start().output_dimension.0 + overshoot
7180        } else {
7181            start
7182        };
7183
7184        start..end
7185    }
7186
7187    /// Returns true if the entirety of the given range is in the buffer's excerpt
7188    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7189        range.start >= self.excerpt.buffer_start_offset()
7190            && range.end <= self.excerpt.buffer_end_offset()
7191    }
7192
7193    pub fn max_buffer_row(&self) -> u32 {
7194        self.excerpt.max_buffer_row
7195    }
7196}
7197
7198impl ExcerptId {
7199    pub fn min() -> Self {
7200        Self(0)
7201    }
7202
7203    pub fn max() -> Self {
7204        Self(u32::MAX)
7205    }
7206
7207    pub fn to_proto(self) -> u64 {
7208        self.0 as _
7209    }
7210
7211    pub fn from_proto(proto: u64) -> Self {
7212        Self(proto as _)
7213    }
7214
7215    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7216        let a = snapshot.excerpt_locator_for_id(*self);
7217        let b = snapshot.excerpt_locator_for_id(*other);
7218        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7219    }
7220}
7221
7222impl From<ExcerptId> for usize {
7223    fn from(val: ExcerptId) -> Self {
7224        val.0 as usize
7225    }
7226}
7227
7228impl fmt::Debug for Excerpt {
7229    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7230        f.debug_struct("Excerpt")
7231            .field("id", &self.id)
7232            .field("locator", &self.locator)
7233            .field("buffer_id", &self.buffer_id)
7234            .field("range", &self.range)
7235            .field("text_summary", &self.text_summary)
7236            .field("has_trailing_newline", &self.has_trailing_newline)
7237            .finish()
7238    }
7239}
7240
7241impl sum_tree::Item for Excerpt {
7242    type Summary = ExcerptSummary;
7243
7244    fn summary(&self, _cx: ()) -> Self::Summary {
7245        let mut text = self.text_summary;
7246        if self.has_trailing_newline {
7247            text += TextSummary::from("\n");
7248        }
7249        ExcerptSummary {
7250            excerpt_id: self.id,
7251            excerpt_locator: self.locator.clone(),
7252            widest_line_number: self.max_buffer_row,
7253            text: text.into(),
7254        }
7255    }
7256}
7257
7258impl sum_tree::Item for ExcerptIdMapping {
7259    type Summary = ExcerptId;
7260
7261    fn summary(&self, _cx: ()) -> Self::Summary {
7262        self.id
7263    }
7264}
7265
7266impl sum_tree::KeyedItem for ExcerptIdMapping {
7267    type Key = ExcerptId;
7268
7269    fn key(&self) -> Self::Key {
7270        self.id
7271    }
7272}
7273
7274impl DiffTransform {
7275    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7276        match self {
7277            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7278            DiffTransform::BufferContent {
7279                inserted_hunk_info, ..
7280            } => *inserted_hunk_info,
7281        }
7282    }
7283}
7284
7285impl sum_tree::Item for DiffTransform {
7286    type Summary = DiffTransformSummary;
7287
7288    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7289        match self {
7290            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7291                input: *summary,
7292                output: *summary,
7293            },
7294            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7295                input: MBTextSummary::default(),
7296                output: summary.into(),
7297            },
7298        }
7299    }
7300}
7301
7302impl DiffTransformSummary {
7303    fn excerpt_len(&self) -> ExcerptOffset {
7304        ExcerptDimension(self.input.len)
7305    }
7306}
7307
7308impl sum_tree::ContextLessSummary for DiffTransformSummary {
7309    fn zero() -> Self {
7310        DiffTransformSummary {
7311            input: MBTextSummary::default(),
7312            output: MBTextSummary::default(),
7313        }
7314    }
7315
7316    fn add_summary(&mut self, other: &Self) {
7317        self.input += other.input;
7318        self.output += other.output;
7319    }
7320}
7321
7322impl sum_tree::ContextLessSummary for ExcerptId {
7323    fn zero() -> Self {
7324        Self(0)
7325    }
7326
7327    fn add_summary(&mut self, summary: &Self) {
7328        *self = cmp::max(*self, *summary);
7329    }
7330}
7331
7332impl sum_tree::ContextLessSummary for ExcerptSummary {
7333    fn zero() -> Self {
7334        Self::default()
7335    }
7336
7337    fn add_summary(&mut self, summary: &Self) {
7338        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7339        self.excerpt_locator = summary.excerpt_locator.clone();
7340        self.text += summary.text;
7341        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7342    }
7343}
7344
7345impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7346    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7347        Ord::cmp(&Some(self), cursor_location)
7348    }
7349}
7350
7351impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7352    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7353        Ord::cmp(self, &cursor_location.excerpt_locator)
7354    }
7355}
7356
7357impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7358where
7359    MBD: MultiBufferDimension + Default,
7360{
7361    fn zero(_: ()) -> Self {
7362        ExcerptDimension(MBD::default())
7363    }
7364
7365    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7366        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7367    }
7368}
7369
7370impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7371    fn zero(_cx: ()) -> Self {
7372        Default::default()
7373    }
7374
7375    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7376        *self = Some(&summary.excerpt_locator);
7377    }
7378}
7379
7380impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7381    fn zero(_cx: ()) -> Self {
7382        Default::default()
7383    }
7384
7385    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7386        *self = Some(summary.excerpt_id);
7387    }
7388}
7389
7390#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7391struct OutputDimension<T>(T);
7392
7393impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7394    fn eq(&self, other: &T) -> bool {
7395        self.0 == *other
7396    }
7397}
7398
7399impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7400    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7401        self.0.partial_cmp(other)
7402    }
7403}
7404
7405impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7406where
7407    T: ops::Sub<U, Output = R>,
7408{
7409    type Output = R;
7410
7411    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7412        self.0 - other.0
7413    }
7414}
7415
7416impl<R, T, U> ops::Add<U> for OutputDimension<T>
7417where
7418    T: ops::Add<U, Output = R>,
7419{
7420    type Output = OutputDimension<R>;
7421
7422    fn add(self, other: U) -> Self::Output {
7423        OutputDimension(self.0 + other)
7424    }
7425}
7426
7427impl<T, U> AddAssign<U> for OutputDimension<T>
7428where
7429    T: AddAssign<U>,
7430{
7431    fn add_assign(&mut self, other: U) {
7432        self.0 += other;
7433    }
7434}
7435
7436impl<T, U> SubAssign<U> for OutputDimension<T>
7437where
7438    T: SubAssign<U>,
7439{
7440    fn sub_assign(&mut self, other: U) {
7441        self.0 -= other;
7442    }
7443}
7444
7445#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7446struct ExcerptDimension<T>(T);
7447
7448impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7449    fn eq(&self, other: &T) -> bool {
7450        self.0 == *other
7451    }
7452}
7453
7454impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7455    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7456        self.0.partial_cmp(other)
7457    }
7458}
7459
7460impl ExcerptOffset {
7461    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7462        self.0.saturating_sub(other.0)
7463    }
7464}
7465
7466impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7467where
7468    T: ops::Sub<U, Output = R>,
7469{
7470    type Output = R;
7471
7472    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7473        self.0 - other.0
7474    }
7475}
7476
7477impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7478where
7479    T: ops::Add<U, Output = R>,
7480{
7481    type Output = ExcerptDimension<R>;
7482
7483    fn add(self, other: U) -> Self::Output {
7484        ExcerptDimension(self.0 + other)
7485    }
7486}
7487
7488impl<T, U> AddAssign<U> for ExcerptDimension<T>
7489where
7490    T: AddAssign<U>,
7491{
7492    fn add_assign(&mut self, other: U) {
7493        self.0 += other;
7494    }
7495}
7496
7497impl<T, U> SubAssign<U> for ExcerptDimension<T>
7498where
7499    T: SubAssign<U>,
7500{
7501    fn sub_assign(&mut self, other: U) {
7502        self.0 -= other;
7503    }
7504}
7505
7506impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7507    fn zero(_: ()) -> Self {
7508        MultiBufferOffset::ZERO
7509    }
7510
7511    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7512        *self += summary.output.len;
7513    }
7514}
7515
7516impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7517    for ExcerptDimension<MBD>
7518where
7519    MBD: MultiBufferDimension + Ord,
7520{
7521    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7522        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7523    }
7524}
7525
7526impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7527    for ExcerptDimension<MBD>
7528where
7529    MBD: MultiBufferDimension + Ord,
7530{
7531    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7532        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7533    }
7534}
7535
7536impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7537    for ExcerptDimension<MBD>
7538{
7539    fn zero(_: ()) -> Self {
7540        ExcerptDimension(MBD::default())
7541    }
7542
7543    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7544        self.0.add_mb_text_summary(&summary.input)
7545    }
7546}
7547
7548impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7549    for OutputDimension<MBD>
7550where
7551    MBD: MultiBufferDimension + Ord,
7552{
7553    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7554        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7555    }
7556}
7557
7558impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7559    for OutputDimension<MBD>
7560{
7561    fn zero(_: ()) -> Self {
7562        OutputDimension(MBD::default())
7563    }
7564
7565    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7566        self.0.add_mb_text_summary(&summary.output)
7567    }
7568}
7569
7570impl MultiBufferRows<'_> {
7571    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7572        self.point = Point::new(row, 0);
7573        self.cursor.seek(&self.point);
7574    }
7575}
7576
7577impl Iterator for MultiBufferRows<'_> {
7578    type Item = RowInfo;
7579
7580    fn next(&mut self) -> Option<Self::Item> {
7581        if self.is_empty && self.point.row == 0 {
7582            self.point += Point::new(1, 0);
7583            return Some(RowInfo {
7584                buffer_id: None,
7585                buffer_row: Some(0),
7586                multibuffer_row: Some(MultiBufferRow(0)),
7587                diff_status: None,
7588                expand_info: None,
7589                wrapped_buffer_row: None,
7590            });
7591        }
7592
7593        let mut region = self.cursor.region()?;
7594        while self.point >= region.range.end {
7595            self.cursor.next();
7596            if let Some(next_region) = self.cursor.region() {
7597                region = next_region;
7598            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7599                let multibuffer_row = MultiBufferRow(self.point.row);
7600                let last_excerpt = self
7601                    .cursor
7602                    .excerpts
7603                    .item()
7604                    .or(self.cursor.excerpts.prev_item())?;
7605                let last_row = last_excerpt
7606                    .range
7607                    .context
7608                    .end
7609                    .to_point(&last_excerpt.buffer)
7610                    .row;
7611
7612                let first_row = last_excerpt
7613                    .range
7614                    .context
7615                    .start
7616                    .to_point(&last_excerpt.buffer)
7617                    .row;
7618
7619                let expand_info = if self.is_singleton {
7620                    None
7621                } else {
7622                    let needs_expand_up = first_row == last_row
7623                        && last_row > 0
7624                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7625                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7626
7627                    if needs_expand_up && needs_expand_down {
7628                        Some(ExpandExcerptDirection::UpAndDown)
7629                    } else if needs_expand_up {
7630                        Some(ExpandExcerptDirection::Up)
7631                    } else if needs_expand_down {
7632                        Some(ExpandExcerptDirection::Down)
7633                    } else {
7634                        None
7635                    }
7636                    .map(|direction| ExpandInfo {
7637                        direction,
7638                        excerpt_id: last_excerpt.id,
7639                    })
7640                };
7641                self.point += Point::new(1, 0);
7642                return Some(RowInfo {
7643                    buffer_id: Some(last_excerpt.buffer_id),
7644                    buffer_row: Some(last_row),
7645                    multibuffer_row: Some(multibuffer_row),
7646                    diff_status: None,
7647                    wrapped_buffer_row: None,
7648                    expand_info,
7649                });
7650            } else {
7651                return None;
7652            };
7653        }
7654
7655        let overshoot = self.point - region.range.start;
7656        let buffer_point = region.buffer_range.start + overshoot;
7657        let expand_info = if self.is_singleton {
7658            None
7659        } else {
7660            let needs_expand_up = self.point.row == region.range.start.row
7661                && self.cursor.is_at_start_of_excerpt()
7662                && buffer_point.row > 0;
7663            let needs_expand_down = (region.excerpt.has_trailing_newline
7664                && self.point.row + 1 == region.range.end.row
7665                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7666                && self.cursor.is_at_end_of_excerpt()
7667                && buffer_point.row < region.buffer.max_point().row;
7668
7669            if needs_expand_up && needs_expand_down {
7670                Some(ExpandExcerptDirection::UpAndDown)
7671            } else if needs_expand_up {
7672                Some(ExpandExcerptDirection::Up)
7673            } else if needs_expand_down {
7674                Some(ExpandExcerptDirection::Down)
7675            } else {
7676                None
7677            }
7678            .map(|direction| ExpandInfo {
7679                direction,
7680                excerpt_id: region.excerpt.id,
7681            })
7682        };
7683
7684        let result = Some(RowInfo {
7685            buffer_id: Some(region.buffer.remote_id()),
7686            buffer_row: Some(buffer_point.row),
7687            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7688            diff_status: region
7689                .diff_hunk_status
7690                .filter(|_| self.point < region.range.end),
7691            expand_info,
7692            wrapped_buffer_row: None,
7693        });
7694        self.point += Point::new(1, 0);
7695        result
7696    }
7697}
7698
7699impl<'a> MultiBufferChunks<'a> {
7700    pub fn offset(&self) -> MultiBufferOffset {
7701        self.range.start
7702    }
7703
7704    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7705        self.diff_transforms.seek(&range.end, Bias::Right);
7706        let mut excerpt_end = self.diff_transforms.start().1;
7707        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7708            let overshoot = range.end - self.diff_transforms.start().0;
7709            excerpt_end += overshoot;
7710        }
7711
7712        self.diff_transforms.seek(&range.start, Bias::Right);
7713        let mut excerpt_start = self.diff_transforms.start().1;
7714        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7715            let overshoot = range.start - self.diff_transforms.start().0;
7716            excerpt_start += overshoot;
7717        }
7718
7719        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7720        self.buffer_chunk.take();
7721        self.range = range;
7722    }
7723
7724    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7725        self.excerpt_offset_range = new_range.clone();
7726        self.excerpts.seek(&new_range.start, Bias::Right);
7727        if let Some(excerpt) = self.excerpts.item() {
7728            let excerpt_start = *self.excerpts.start();
7729            if let Some(excerpt_chunks) = self
7730                .excerpt_chunks
7731                .as_mut()
7732                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7733            {
7734                excerpt.seek_chunks(
7735                    excerpt_chunks,
7736                    (self.excerpt_offset_range.start - excerpt_start)
7737                        ..(self.excerpt_offset_range.end - excerpt_start),
7738                );
7739            } else {
7740                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7741                    (self.excerpt_offset_range.start - excerpt_start)
7742                        ..(self.excerpt_offset_range.end - excerpt_start),
7743                    self.language_aware,
7744                ));
7745            }
7746        } else {
7747            self.excerpt_chunks = None;
7748        }
7749    }
7750
7751    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7752        loop {
7753            if self.excerpt_offset_range.is_empty() {
7754                return None;
7755            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7756                self.excerpt_offset_range.start += chunk.text.len();
7757                return Some(chunk);
7758            } else {
7759                self.excerpts.next();
7760                let excerpt = self.excerpts.item()?;
7761                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7762                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7763                    self.language_aware,
7764                ));
7765            }
7766        }
7767    }
7768}
7769
7770impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7771    type Item = &'a str;
7772
7773    fn next(&mut self) -> Option<Self::Item> {
7774        let mut region = self.cursor.region()?;
7775        if self.offset == region.range.start {
7776            self.cursor.prev();
7777            region = self.cursor.region()?;
7778            let start_overshoot = self.start.saturating_sub(region.range.start);
7779            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7780                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7781            ));
7782        }
7783
7784        if self.offset == region.range.end && region.has_trailing_newline {
7785            self.offset -= 1;
7786            Some("\n")
7787        } else {
7788            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7789            self.offset -= chunk.len();
7790            Some(chunk)
7791        }
7792    }
7793}
7794
7795impl<'a> Iterator for MultiBufferChunks<'a> {
7796    type Item = Chunk<'a>;
7797
7798    fn next(&mut self) -> Option<Chunk<'a>> {
7799        if self.range.start >= self.range.end {
7800            return None;
7801        }
7802        if self.range.start == self.diff_transforms.end().0 {
7803            self.diff_transforms.next();
7804        }
7805
7806        let diff_transform_start = self.diff_transforms.start().0;
7807        let diff_transform_end = self.diff_transforms.end().0;
7808        debug_assert!(
7809            self.range.start < diff_transform_end,
7810            "{:?} < {:?} of ({1:?}..{2:?})",
7811            self.range.start,
7812            diff_transform_end,
7813            diff_transform_start
7814        );
7815
7816        let diff_transform = self.diff_transforms.item()?;
7817        match diff_transform {
7818            DiffTransform::BufferContent { .. } => {
7819                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7820                    chunk
7821                } else {
7822                    let chunk = self.next_excerpt_chunk().unwrap();
7823                    self.buffer_chunk.insert(chunk)
7824                };
7825
7826                let chunk_end = self.range.start + chunk.text.len();
7827                let diff_transform_end = diff_transform_end.min(self.range.end);
7828
7829                if diff_transform_end < chunk_end {
7830                    let split_idx = diff_transform_end - self.range.start;
7831                    let (before, after) = chunk.text.split_at(split_idx);
7832                    self.range.start = diff_transform_end;
7833                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7834                    let chars = chunk.chars & mask;
7835                    let tabs = chunk.tabs & mask;
7836
7837                    chunk.text = after;
7838                    chunk.chars = chunk.chars >> split_idx;
7839                    chunk.tabs = chunk.tabs >> split_idx;
7840
7841                    Some(Chunk {
7842                        text: before,
7843                        chars,
7844                        tabs,
7845                        ..chunk.clone()
7846                    })
7847                } else {
7848                    self.range.start = chunk_end;
7849                    self.buffer_chunk.take()
7850                }
7851            }
7852            DiffTransform::DeletedHunk {
7853                buffer_id,
7854                base_text_byte_range,
7855                has_trailing_newline,
7856                ..
7857            } => {
7858                let base_text_start =
7859                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7860                let base_text_end =
7861                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7862                let base_text_end = base_text_end.min(base_text_byte_range.end);
7863
7864                let mut chunks = if let Some((_, mut chunks)) = self
7865                    .diff_base_chunks
7866                    .take()
7867                    .filter(|(id, _)| id == buffer_id)
7868                {
7869                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7870                    {
7871                        chunks.seek(base_text_start..base_text_end);
7872                    }
7873                    chunks
7874                } else {
7875                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7876                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7877                };
7878
7879                let chunk = if let Some(chunk) = chunks.next() {
7880                    self.range.start += chunk.text.len();
7881                    self.diff_base_chunks = Some((*buffer_id, chunks));
7882                    chunk
7883                } else {
7884                    debug_assert!(has_trailing_newline);
7885                    self.range.start += "\n".len();
7886                    Chunk {
7887                        text: "\n",
7888                        chars: 1u128,
7889                        ..Default::default()
7890                    }
7891                };
7892                Some(chunk)
7893            }
7894        }
7895    }
7896}
7897
7898impl MultiBufferBytes<'_> {
7899    fn consume(&mut self, len: usize) {
7900        self.range.start += len;
7901        self.chunk = &self.chunk[len..];
7902
7903        if !self.range.is_empty() && self.chunk.is_empty() {
7904            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7905                self.chunk = chunk;
7906            } else if self.has_trailing_newline {
7907                self.has_trailing_newline = false;
7908                self.chunk = b"\n";
7909            } else {
7910                self.cursor.next();
7911                if let Some(region) = self.cursor.region() {
7912                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7913                        region.buffer_range.start
7914                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7915                                .min(region.buffer_range.end),
7916                    );
7917                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7918                    self.excerpt_bytes = Some(excerpt_bytes);
7919                    self.has_trailing_newline =
7920                        region.has_trailing_newline && self.range.end >= region.range.end;
7921                    if self.chunk.is_empty() && self.has_trailing_newline {
7922                        self.has_trailing_newline = false;
7923                        self.chunk = b"\n";
7924                    }
7925                }
7926            }
7927        }
7928    }
7929}
7930
7931impl<'a> Iterator for MultiBufferBytes<'a> {
7932    type Item = &'a [u8];
7933
7934    fn next(&mut self) -> Option<Self::Item> {
7935        let chunk = self.chunk;
7936        if chunk.is_empty() {
7937            None
7938        } else {
7939            self.consume(chunk.len());
7940            Some(chunk)
7941        }
7942    }
7943}
7944
7945impl io::Read for MultiBufferBytes<'_> {
7946    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7947        let len = cmp::min(buf.len(), self.chunk.len());
7948        buf[..len].copy_from_slice(&self.chunk[..len]);
7949        if len > 0 {
7950            self.consume(len);
7951        }
7952        Ok(len)
7953    }
7954}
7955
7956impl io::Read for ReversedMultiBufferBytes<'_> {
7957    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7958        let len = cmp::min(buf.len(), self.chunk.len());
7959        buf[..len].copy_from_slice(&self.chunk[..len]);
7960        buf[..len].reverse();
7961        if len > 0 {
7962            self.range.end -= len;
7963            self.chunk = &self.chunk[..self.chunk.len() - len];
7964            if !self.range.is_empty()
7965                && self.chunk.is_empty()
7966                && let Some(chunk) = self.chunks.next()
7967            {
7968                self.chunk = chunk.as_bytes();
7969            }
7970        }
7971        Ok(len)
7972    }
7973}
7974
7975impl<'a> Iterator for ExcerptChunks<'a> {
7976    type Item = Chunk<'a>;
7977
7978    fn next(&mut self) -> Option<Self::Item> {
7979        if let Some(chunk) = self.content_chunks.next() {
7980            return Some(chunk);
7981        }
7982
7983        if self.has_footer {
7984            let text = "\n";
7985            let chars = 0b1;
7986            self.has_footer = false;
7987            return Some(Chunk {
7988                text,
7989                chars,
7990                ..Default::default()
7991            });
7992        }
7993
7994        None
7995    }
7996}
7997
7998impl ToOffset for Point {
7999    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8000        snapshot.point_to_offset(*self)
8001    }
8002    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8003        snapshot.point_to_offset_utf16(*self)
8004    }
8005}
8006
8007impl ToOffset for MultiBufferOffset {
8008    #[track_caller]
8009    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8010        assert!(
8011            *self <= snapshot.len(),
8012            "offset {} is greater than the snapshot.len() {}",
8013            self.0,
8014            snapshot.len().0,
8015        );
8016        *self
8017    }
8018    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8019        snapshot.offset_to_offset_utf16(*self)
8020    }
8021}
8022
8023impl ToOffset for MultiBufferOffsetUtf16 {
8024    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8025        snapshot.offset_utf16_to_offset(*self)
8026    }
8027
8028    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8029        *self
8030    }
8031}
8032
8033impl ToOffset for PointUtf16 {
8034    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8035        snapshot.point_utf16_to_offset(*self)
8036    }
8037    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8038        snapshot.point_utf16_to_offset_utf16(*self)
8039    }
8040}
8041
8042impl ToPoint for MultiBufferOffset {
8043    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8044        snapshot.offset_to_point(*self)
8045    }
8046    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8047        snapshot.offset_to_point_utf16(*self)
8048    }
8049}
8050
8051impl ToPoint for Point {
8052    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8053        *self
8054    }
8055    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8056        snapshot.point_to_point_utf16(*self)
8057    }
8058}
8059
8060impl ToPoint for PointUtf16 {
8061    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8062        snapshot.point_utf16_to_point(*self)
8063    }
8064    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8065        *self
8066    }
8067}
8068
8069impl From<ExcerptId> for EntityId {
8070    fn from(id: ExcerptId) -> Self {
8071        EntityId::from(id.0 as u64)
8072    }
8073}
8074
8075#[cfg(debug_assertions)]
8076pub mod debug {
8077    use super::*;
8078
8079    pub trait ToMultiBufferDebugRanges {
8080        fn to_multi_buffer_debug_ranges(
8081            &self,
8082            snapshot: &MultiBufferSnapshot,
8083        ) -> Vec<Range<MultiBufferOffset>>;
8084    }
8085
8086    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8087        fn to_multi_buffer_debug_ranges(
8088            &self,
8089            snapshot: &MultiBufferSnapshot,
8090        ) -> Vec<Range<MultiBufferOffset>> {
8091            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8092        }
8093    }
8094
8095    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8096        fn to_multi_buffer_debug_ranges(
8097            &self,
8098            snapshot: &MultiBufferSnapshot,
8099        ) -> Vec<Range<MultiBufferOffset>> {
8100            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8101                .to_multi_buffer_debug_ranges(snapshot)
8102        }
8103    }
8104
8105    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8106        fn to_multi_buffer_debug_ranges(
8107            &self,
8108            snapshot: &MultiBufferSnapshot,
8109        ) -> Vec<Range<MultiBufferOffset>> {
8110            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8111        }
8112    }
8113
8114    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8115        fn to_multi_buffer_debug_ranges(
8116            &self,
8117            snapshot: &MultiBufferSnapshot,
8118        ) -> Vec<Range<MultiBufferOffset>> {
8119            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8120        }
8121    }
8122
8123    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8124        fn to_multi_buffer_debug_ranges(
8125            &self,
8126            snapshot: &MultiBufferSnapshot,
8127        ) -> Vec<Range<MultiBufferOffset>> {
8128            self.iter()
8129                .map(|item| {
8130                    let offset = item.to_offset(snapshot);
8131                    offset..offset
8132                })
8133                .collect()
8134        }
8135    }
8136
8137    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8138        fn to_multi_buffer_debug_ranges(
8139            &self,
8140            snapshot: &MultiBufferSnapshot,
8141        ) -> Vec<Range<MultiBufferOffset>> {
8142            self.iter()
8143                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8144                .collect()
8145        }
8146    }
8147}