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