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        let use_path_excerpts = !self.excerpts_by_path.is_empty();
3605
3606        let mut buffers = Vec::new();
3607        for _ in 0..mutation_count {
3608            if rng.random_bool(0.05) {
3609                log::info!("Clearing multi-buffer");
3610                self.clear(cx);
3611                continue;
3612            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3613                let ids = self.excerpt_ids();
3614                let mut excerpts = HashSet::default();
3615                for _ in 0..rng.random_range(0..ids.len()) {
3616                    excerpts.extend(ids.choose(rng).copied());
3617                }
3618
3619                let line_count = rng.random_range(0..5);
3620
3621                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3622
3623                self.expand_excerpts(
3624                    excerpts.iter().cloned(),
3625                    line_count,
3626                    ExpandExcerptDirection::UpAndDown,
3627                    cx,
3628                );
3629                continue;
3630            }
3631
3632            let excerpt_ids = self.excerpt_ids();
3633            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3634                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3635                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3636                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3637                    let buffer = buffers.last().unwrap().read(cx);
3638                    log::info!(
3639                        "Creating new buffer {} with text: {:?}",
3640                        buffer.remote_id(),
3641                        buffer.text()
3642                    );
3643                    buffers.last().unwrap().clone()
3644                } else {
3645                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3646                };
3647
3648                let buffer = buffer_handle.read(cx);
3649                let buffer_text = buffer.text();
3650                let ranges = (0..rng.random_range(0..5))
3651                    .map(|_| {
3652                        let end_ix =
3653                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3654                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3655                        ExcerptRange::new(start_ix..end_ix)
3656                    })
3657                    .collect::<Vec<_>>();
3658                log::info!(
3659                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3660                    buffer_handle.read(cx).remote_id(),
3661                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3662                    ranges
3663                        .iter()
3664                        .map(|r| &buffer_text[r.context.clone()])
3665                        .collect::<Vec<_>>()
3666                );
3667
3668                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3669                log::info!("Inserted with ids: {:?}", excerpt_id);
3670            } else {
3671                let remove_count = rng.random_range(1..=excerpt_ids.len());
3672                let mut excerpts_to_remove = excerpt_ids
3673                    .choose_multiple(rng, remove_count)
3674                    .cloned()
3675                    .collect::<Vec<_>>();
3676                let snapshot = self.snapshot.borrow();
3677                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3678                drop(snapshot);
3679                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3680                self.remove_excerpts(excerpts_to_remove, cx);
3681            }
3682        }
3683    }
3684
3685    pub fn randomly_mutate(
3686        &mut self,
3687        rng: &mut impl rand::Rng,
3688        mutation_count: usize,
3689        cx: &mut Context<Self>,
3690    ) {
3691        use rand::prelude::*;
3692
3693        if rng.random_bool(0.7) || self.singleton {
3694            let buffer = self
3695                .buffers
3696                .values()
3697                .choose(rng)
3698                .map(|state| state.buffer.clone());
3699
3700            if let Some(buffer) = buffer {
3701                buffer.update(cx, |buffer, cx| {
3702                    if rng.random() {
3703                        buffer.randomly_edit(rng, mutation_count, cx);
3704                    } else {
3705                        buffer.randomly_undo_redo(rng, cx);
3706                    }
3707                });
3708            } else {
3709                self.randomly_edit(rng, mutation_count, cx);
3710            }
3711        } else {
3712            self.randomly_edit_excerpts(rng, mutation_count, cx);
3713        }
3714
3715        self.check_invariants(cx);
3716    }
3717
3718    fn check_invariants(&self, cx: &App) {
3719        self.read(cx).check_invariants();
3720    }
3721}
3722
3723impl EventEmitter<Event> for MultiBuffer {}
3724
3725impl MultiBufferSnapshot {
3726    pub fn text(&self) -> String {
3727        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3728            .map(|chunk| chunk.text)
3729            .collect()
3730    }
3731
3732    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3733        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3734            .flat_map(|c| c.chars().rev())
3735    }
3736
3737    fn reversed_chunks_in_range(
3738        &self,
3739        range: Range<MultiBufferOffset>,
3740    ) -> ReversedMultiBufferChunks<'_> {
3741        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3742        cursor.seek(&range.end);
3743        let current_chunks = cursor.region().as_ref().map(|region| {
3744            let start_overshoot = range.start.saturating_sub(region.range.start);
3745            let end_overshoot = range.end - region.range.start;
3746            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3747            let start = region.buffer_range.start + start_overshoot;
3748            region.buffer.reversed_chunks_in_range(start..end)
3749        });
3750        ReversedMultiBufferChunks {
3751            cursor,
3752            current_chunks,
3753            start: range.start,
3754            offset: range.end,
3755        }
3756    }
3757
3758    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3759        let offset = position.to_offset(self);
3760        self.text_for_range(offset..self.len())
3761            .flat_map(|chunk| chunk.chars())
3762    }
3763
3764    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3765        self.chunks(range, false).map(|chunk| chunk.text)
3766    }
3767
3768    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3769        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3770            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3771    }
3772
3773    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3774    where
3775        T: ToOffset,
3776    {
3777        let position = position.to_offset(self);
3778        position == self.clip_offset(position, Bias::Left)
3779            && self
3780                .bytes_in_range(position..self.len())
3781                .flatten()
3782                .copied()
3783                .take(needle.len())
3784                .eq(needle.bytes())
3785    }
3786
3787    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3788        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3789    }
3790
3791    pub fn diff_hunks_in_range<T: ToPoint>(
3792        &self,
3793        range: Range<T>,
3794    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3795        let query_range = range.start.to_point(self)..range.end.to_point(self);
3796        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3797            let diff = self.diffs.get(&buffer.remote_id())?;
3798            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3799                if let Some(main_buffer) = &diff.main_buffer {
3800                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3801                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3802                    Box::new(
3803                        diff.hunks_intersecting_base_text_range(
3804                            buffer_start..buffer_end,
3805                            main_buffer,
3806                        )
3807                        .map(move |hunk| (hunk, buffer, true)),
3808                    )
3809                } else {
3810                    let buffer_start = buffer.anchor_before(buffer_range.start);
3811                    let buffer_end = buffer.anchor_after(buffer_range.end);
3812                    Box::new(
3813                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3814                            .map(move |hunk| (hunk, buffer, false)),
3815                    )
3816                };
3817            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3818                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3819                    return None;
3820                }
3821                let range = if is_inverted {
3822                    hunk.diff_base_byte_range.to_point(&buffer)
3823                } else {
3824                    hunk.range.clone()
3825                };
3826                Some((range, (hunk, is_inverted)))
3827            }))
3828        })
3829        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3830            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3831            {
3832                return None;
3833            }
3834            let end_row = if range.end.column == 0 {
3835                range.end.row
3836            } else {
3837                range.end.row + 1
3838            };
3839
3840            let word_diffs = (!hunk.base_word_diffs.is_empty()
3841                || !hunk.buffer_word_diffs.is_empty())
3842            .then(|| {
3843                let hunk_start_offset = if is_inverted {
3844                    Anchor::in_buffer(
3845                        excerpt.id,
3846                        excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3847                    )
3848                    .to_offset(self)
3849                } else {
3850                    Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_offset(self)
3851                };
3852
3853                let mut word_diffs = hunk
3854                    .base_word_diffs
3855                    .iter()
3856                    .map(|diff| hunk_start_offset + diff.start..hunk_start_offset + diff.end)
3857                    .collect::<Vec<_>>();
3858                if !is_inverted {
3859                    word_diffs.extend(
3860                        hunk.buffer_word_diffs
3861                            .into_iter()
3862                            .map(|diff| Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)),
3863                    );
3864                }
3865                word_diffs
3866            })
3867            .unwrap_or_default();
3868
3869            let buffer_range = if is_inverted {
3870                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3871                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3872            } else {
3873                hunk.buffer_range.clone()
3874            };
3875            Some(MultiBufferDiffHunk {
3876                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3877                buffer_id: excerpt.buffer_id,
3878                excerpt_id: excerpt.id,
3879                buffer_range,
3880                word_diffs,
3881                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3882                    ..BufferOffset(hunk.diff_base_byte_range.end),
3883                secondary_status: hunk.secondary_status,
3884            })
3885        })
3886    }
3887
3888    fn excerpts_for_range<T: ToOffset>(
3889        &self,
3890        range: Range<T>,
3891    ) -> impl Iterator<Item = &Excerpt> + '_ {
3892        let range = range.start.to_offset(self)..range.end.to_offset(self);
3893        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3894        cursor.seek(&range.start);
3895        std::iter::from_fn(move || {
3896            let region = cursor.region()?;
3897            if region.range.start > range.end
3898                || region.range.start == range.end && region.range.start > range.start
3899            {
3900                return None;
3901            }
3902            cursor.next_excerpt();
3903            Some(region.excerpt)
3904        })
3905    }
3906
3907    pub fn excerpt_ids_for_range<T: ToOffset>(
3908        &self,
3909        range: Range<T>,
3910    ) -> impl Iterator<Item = ExcerptId> + '_ {
3911        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3912    }
3913
3914    pub fn buffer_ids_for_range<T: ToOffset>(
3915        &self,
3916        range: Range<T>,
3917    ) -> impl Iterator<Item = BufferId> + '_ {
3918        self.excerpts_for_range(range)
3919            .map(|excerpt| excerpt.buffer_id)
3920    }
3921
3922    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3923        &self,
3924        ranges: impl Iterator<Item = Range<T>>,
3925    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3926        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3927    }
3928
3929    pub fn range_to_buffer_ranges<T: ToOffset>(
3930        &self,
3931        range: Range<T>,
3932    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3933        let start = range.start.to_offset(self);
3934        let end = range.end.to_offset(self);
3935
3936        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3937        cursor.seek(&start);
3938
3939        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
3940        while let Some(region) = cursor.region() {
3941            if region.range.start > end {
3942                break;
3943            }
3944            if region.is_main_buffer {
3945                let start_overshoot = start.saturating_sub(region.range.start);
3946                let end_overshoot = end.saturating_sub(region.range.start);
3947                let start = region
3948                    .buffer_range
3949                    .end
3950                    .min(region.buffer_range.start + start_overshoot);
3951                let end = region
3952                    .buffer_range
3953                    .end
3954                    .min(region.buffer_range.start + end_overshoot);
3955                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3956                    *excerpt_id == region.excerpt.id && prev_range.end == start
3957                }) {
3958                    prev.1.end = end;
3959                } else {
3960                    result.push((region.buffer, start..end, region.excerpt.id));
3961                }
3962            }
3963            cursor.next();
3964        }
3965        result
3966    }
3967
3968    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3969        &self,
3970        range: Range<T>,
3971    ) -> impl Iterator<
3972        Item = (
3973            &BufferSnapshot,
3974            Range<BufferOffset>,
3975            ExcerptId,
3976            Option<Anchor>,
3977        ),
3978    > + '_ {
3979        let start = range.start.to_offset(self);
3980        let end = range.end.to_offset(self);
3981
3982        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3983        cursor.seek(&start);
3984
3985        std::iter::from_fn(move || {
3986            let region = cursor.region()?;
3987            if region.range.start > end {
3988                return None;
3989            }
3990            let start_overshoot = start.saturating_sub(region.range.start);
3991            let end_overshoot = end.saturating_sub(region.range.start);
3992            let start = region
3993                .buffer_range
3994                .end
3995                .min(region.buffer_range.start + start_overshoot);
3996            let end = region
3997                .buffer_range
3998                .end
3999                .min(region.buffer_range.start + end_overshoot);
4000
4001            let region_excerpt_id = region.excerpt.id;
4002            let deleted_hunk_anchor = if region.is_main_buffer {
4003                None
4004            } else {
4005                Some(self.anchor_before(region.range.start))
4006            };
4007            let result = (
4008                region.buffer,
4009                start..end,
4010                region_excerpt_id,
4011                deleted_hunk_anchor,
4012            );
4013            cursor.next();
4014            Some(result)
4015        })
4016    }
4017
4018    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4019    /// coordinates.
4020    ///
4021    /// The given callback will be called for every excerpt intersecting the given range. It will
4022    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4023    /// The callback should return an iterator of metadata items from that buffer, each paired
4024    /// with a buffer range.
4025    ///
4026    /// The returned iterator yields each of these metadata items, paired with its range in
4027    /// multi-buffer coordinates.
4028    fn lift_buffer_metadata<'a, MBD, M, I>(
4029        &'a self,
4030        query_range: Range<MBD>,
4031        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4032    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4033    where
4034        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4035        MBD: MultiBufferDimension
4036            + Ord
4037            + Sub<Output = MBD::TextDimension>
4038            + ops::Add<MBD::TextDimension, Output = MBD>
4039            + ops::AddAssign<MBD::TextDimension>,
4040        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4041            + ops::Add<Output = MBD::TextDimension>
4042            + AddAssign<MBD::TextDimension>
4043            + Ord,
4044    {
4045        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4046        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4047
4048        // Find the excerpt and buffer offset where the given range ends.
4049        cursor.seek(&query_range.end);
4050        let mut range_end = None;
4051        while let Some(region) = cursor.region() {
4052            if region.is_main_buffer {
4053                let mut buffer_end = region.buffer_range.start;
4054                let overshoot = if query_range.end > region.range.start {
4055                    query_range.end - region.range.start
4056                } else {
4057                    <MBD::TextDimension>::default()
4058                };
4059                buffer_end = buffer_end + overshoot;
4060                range_end = Some((region.excerpt.id, buffer_end));
4061                break;
4062            }
4063            cursor.next();
4064        }
4065
4066        cursor.seek(&query_range.start);
4067
4068        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4069            && region.range.start > MBD::default()
4070        {
4071            cursor.prev()
4072        }
4073
4074        iter::from_fn(move || {
4075            loop {
4076                let excerpt = cursor.excerpt()?;
4077
4078                // If we have already retrieved metadata for this excerpt, continue to use it.
4079                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4080                    .as_mut()
4081                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4082                {
4083                    Some(metadata)
4084                }
4085                // Otherwise, compute the intersection of the input range with the excerpt's range,
4086                // and retrieve the metadata for the resulting range.
4087                else {
4088                    let region = cursor.region()?;
4089                    let mut buffer_start;
4090                    if region.is_main_buffer {
4091                        buffer_start = region.buffer_range.start;
4092                        if query_range.start > region.range.start {
4093                            let overshoot = query_range.start - region.range.start;
4094                            buffer_start = buffer_start + overshoot;
4095                        }
4096                        buffer_start = buffer_start.min(region.buffer_range.end);
4097                    } else {
4098                        buffer_start = cursor.main_buffer_position()?;
4099                    };
4100                    let mut buffer_end = excerpt
4101                        .range
4102                        .context
4103                        .end
4104                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4105                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4106                        && excerpt.id == end_excerpt_id
4107                    {
4108                        buffer_end = buffer_end.min(end_buffer_offset);
4109                    }
4110
4111                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4112                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4113                    })
4114                };
4115
4116                // Visit each metadata item.
4117                if let Some((metadata_buffer_range, metadata)) =
4118                    metadata_iter.and_then(Iterator::next)
4119                {
4120                    // Find the multibuffer regions that contain the start and end of
4121                    // the metadata item's range.
4122                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4123                        while let Some(region) = cursor.region() {
4124                            if region.is_main_buffer
4125                                && (region.buffer_range.end >= metadata_buffer_range.start
4126                                    || cursor.is_at_end_of_excerpt())
4127                            {
4128                                break;
4129                            }
4130                            cursor.next();
4131                        }
4132                    }
4133                    let start_region = cursor.region()?;
4134                    while let Some(region) = cursor.region() {
4135                        if region.is_main_buffer
4136                            && (region.buffer_range.end > metadata_buffer_range.end
4137                                || cursor.is_at_end_of_excerpt())
4138                        {
4139                            break;
4140                        }
4141                        cursor.next();
4142                    }
4143                    let end_region = cursor.region();
4144
4145                    // Convert the metadata item's range into multibuffer coordinates.
4146                    let mut start_position = start_region.range.start;
4147                    let region_buffer_start = start_region.buffer_range.start;
4148                    if start_region.is_main_buffer
4149                        && metadata_buffer_range.start > region_buffer_start
4150                    {
4151                        start_position =
4152                            start_position + (metadata_buffer_range.start - region_buffer_start);
4153                        start_position = start_position.min(start_region.range.end);
4154                    }
4155
4156                    let mut end_position = self.max_position();
4157                    if let Some(end_region) = &end_region {
4158                        end_position = end_region.range.start;
4159                        debug_assert!(end_region.is_main_buffer);
4160                        let region_buffer_start = end_region.buffer_range.start;
4161                        if metadata_buffer_range.end > region_buffer_start {
4162                            end_position =
4163                                end_position + (metadata_buffer_range.end - region_buffer_start);
4164                        }
4165                        end_position = end_position.min(end_region.range.end);
4166                    }
4167
4168                    if start_position <= query_range.end && end_position >= query_range.start {
4169                        return Some((start_position..end_position, metadata, excerpt));
4170                    }
4171                }
4172                // When there are no more metadata items for this excerpt, move to the next excerpt.
4173                else {
4174                    current_excerpt_metadata.take();
4175                    if let Some((end_excerpt_id, _)) = range_end
4176                        && excerpt.id == end_excerpt_id
4177                    {
4178                        return None;
4179                    }
4180                    cursor.next_excerpt();
4181                }
4182            }
4183        })
4184    }
4185
4186    // FIXME need to make this work with inverted diffs
4187    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4188        let offset = position.to_offset(self);
4189
4190        let mut cursor = self
4191            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4192            );
4193        cursor.seek(&DimensionPair {
4194            key: offset,
4195            value: None,
4196        });
4197        cursor.seek_to_start_of_current_excerpt();
4198        let excerpt = cursor.excerpt()?;
4199
4200        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4201        let current_position = self
4202            .anchor_before(offset)
4203            .text_anchor
4204            .to_offset(&excerpt.buffer);
4205        let excerpt_end = excerpt
4206            .buffer
4207            .anchor_before(excerpt_end.min(current_position));
4208
4209        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4210            for hunk in diff.hunks_intersecting_range_rev(
4211                excerpt.range.context.start..excerpt_end,
4212                &excerpt.buffer,
4213            ) {
4214                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4215                if hunk_end >= current_position {
4216                    continue;
4217                }
4218                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4219                return Some(MultiBufferRow(start.row));
4220            }
4221        }
4222
4223        loop {
4224            cursor.prev_excerpt();
4225            let excerpt = cursor.excerpt()?;
4226
4227            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4228                continue;
4229            };
4230            let mut hunks =
4231                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4232            let Some(hunk) = hunks.next() else {
4233                continue;
4234            };
4235            let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4236            return Some(MultiBufferRow(start.row));
4237        }
4238    }
4239
4240    pub fn has_diff_hunks(&self) -> bool {
4241        self.diffs.values().any(|diff| !diff.is_empty())
4242    }
4243
4244    pub fn is_inside_word<T: ToOffset>(
4245        &self,
4246        position: T,
4247        scope_context: Option<CharScopeContext>,
4248    ) -> bool {
4249        let position = position.to_offset(self);
4250        let classifier = self
4251            .char_classifier_at(position)
4252            .scope_context(scope_context);
4253        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4254        let prev_char_kind = self
4255            .reversed_chars_at(position)
4256            .next()
4257            .map(|c| classifier.kind(c));
4258        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4259    }
4260
4261    pub fn surrounding_word<T: ToOffset>(
4262        &self,
4263        start: T,
4264        scope_context: Option<CharScopeContext>,
4265    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4266        let mut start = start.to_offset(self);
4267        let mut end = start;
4268        let mut next_chars = self.chars_at(start).peekable();
4269        let mut prev_chars = self.reversed_chars_at(start).peekable();
4270
4271        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4272
4273        let word_kind = cmp::max(
4274            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4275            next_chars.peek().copied().map(|c| classifier.kind(c)),
4276        );
4277
4278        for ch in prev_chars {
4279            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4280                start -= ch.len_utf8();
4281            } else {
4282                break;
4283            }
4284        }
4285
4286        for ch in next_chars {
4287            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4288                end += ch.len_utf8();
4289            } else {
4290                break;
4291            }
4292        }
4293
4294        (start..end, word_kind)
4295    }
4296
4297    pub fn char_kind_before<T: ToOffset>(
4298        &self,
4299        start: T,
4300        scope_context: Option<CharScopeContext>,
4301    ) -> Option<CharKind> {
4302        let start = start.to_offset(self);
4303        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4304        self.reversed_chars_at(start)
4305            .next()
4306            .map(|ch| classifier.kind(ch))
4307    }
4308
4309    pub fn is_singleton(&self) -> bool {
4310        self.singleton
4311    }
4312
4313    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4314        if self.singleton {
4315            self.excerpts
4316                .iter()
4317                .next()
4318                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4319        } else {
4320            None
4321        }
4322    }
4323
4324    pub fn len(&self) -> MultiBufferOffset {
4325        self.diff_transforms.summary().output.len
4326    }
4327
4328    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4329        MBD::from_summary(&self.text_summary())
4330    }
4331
4332    pub fn is_empty(&self) -> bool {
4333        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4334    }
4335
4336    pub fn widest_line_number(&self) -> u32 {
4337        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4338        self.excerpts.summary().widest_line_number + 1
4339    }
4340
4341    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4342        let range = range.start.to_offset(self)..range.end.to_offset(self);
4343        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4344        excerpts.seek(&range.start);
4345
4346        let mut chunk;
4347        let mut has_trailing_newline;
4348        let excerpt_bytes;
4349        if let Some(region) = excerpts.region() {
4350            let mut bytes = region.buffer.bytes_in_range(
4351                region.buffer_range.start + (range.start - region.range.start)
4352                    ..(region.buffer_range.start + (range.end - region.range.start))
4353                        .min(region.buffer_range.end),
4354            );
4355            chunk = bytes.next().unwrap_or(&[][..]);
4356            excerpt_bytes = Some(bytes);
4357            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4358            if chunk.is_empty() && has_trailing_newline {
4359                chunk = b"\n";
4360                has_trailing_newline = false;
4361            }
4362        } else {
4363            chunk = &[][..];
4364            excerpt_bytes = None;
4365            has_trailing_newline = false;
4366        };
4367
4368        MultiBufferBytes {
4369            range,
4370            cursor: excerpts,
4371            excerpt_bytes,
4372            has_trailing_newline,
4373            chunk,
4374        }
4375    }
4376
4377    pub fn reversed_bytes_in_range<T: ToOffset>(
4378        &self,
4379        range: Range<T>,
4380    ) -> ReversedMultiBufferBytes<'_> {
4381        let range = range.start.to_offset(self)..range.end.to_offset(self);
4382        let mut chunks = self.reversed_chunks_in_range(range.clone());
4383        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4384        ReversedMultiBufferBytes {
4385            range,
4386            chunks,
4387            chunk,
4388        }
4389    }
4390
4391    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4392        let mut cursor = self.cursor::<Point, Point>();
4393        cursor.seek(&Point::new(start_row.0, 0));
4394        let mut result = MultiBufferRows {
4395            point: Point::new(0, 0),
4396            is_empty: self.excerpts.is_empty(),
4397            is_singleton: self.is_singleton(),
4398            cursor,
4399        };
4400        result.seek(start_row);
4401        result
4402    }
4403
4404    pub fn chunks<T: ToOffset>(
4405        &self,
4406        range: Range<T>,
4407        language_aware: bool,
4408    ) -> MultiBufferChunks<'_> {
4409        let mut chunks = MultiBufferChunks {
4410            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4411                ..ExcerptDimension(MultiBufferOffset::ZERO),
4412            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4413            excerpts: self.excerpts.cursor(()),
4414            diff_transforms: self.diff_transforms.cursor(()),
4415            diffs: &self.diffs,
4416            diff_base_chunks: None,
4417            excerpt_chunks: None,
4418            buffer_chunk: None,
4419            language_aware,
4420        };
4421        let range = range.start.to_offset(self)..range.end.to_offset(self);
4422        chunks.seek(range);
4423        chunks
4424    }
4425
4426    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4427        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4428    }
4429
4430    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4431        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4432    }
4433
4434    pub fn clip_offset_utf16(
4435        &self,
4436        offset: MultiBufferOffsetUtf16,
4437        bias: Bias,
4438    ) -> MultiBufferOffsetUtf16 {
4439        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4440    }
4441
4442    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4443        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4444            buffer.clip_point_utf16(Unclipped(point), bias)
4445        })
4446    }
4447
4448    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4449        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4450    }
4451
4452    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4453        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4454    }
4455
4456    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4457        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4458    }
4459
4460    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4461        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4462    }
4463
4464    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4465        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4466    }
4467
4468    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4469        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4470    }
4471
4472    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4473        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4474    }
4475
4476    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4477        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4478    }
4479
4480    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4481        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4482    }
4483
4484    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4485        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4486    }
4487
4488    fn clip_dimension<MBD, BD>(
4489        &self,
4490        position: MBD,
4491        bias: Bias,
4492        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4493    ) -> MBD
4494    where
4495        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4496        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4497    {
4498        let mut cursor = self.cursor::<MBD, BD>();
4499        cursor.seek(&position);
4500        if let Some(region) = cursor.region() {
4501            if position >= region.range.end {
4502                return region.range.end;
4503            }
4504            let overshoot = position - region.range.start;
4505            let mut buffer_position = region.buffer_range.start;
4506            buffer_position += overshoot;
4507            let clipped_buffer_position =
4508                clip_buffer_position(region.buffer, buffer_position, bias);
4509            let mut position = region.range.start;
4510            position += clipped_buffer_position - region.buffer_range.start;
4511            position
4512        } else {
4513            self.max_position()
4514        }
4515    }
4516
4517    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4518        &self,
4519        key: MBR1,
4520        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4521    ) -> MBR2
4522    where
4523        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4524        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4525        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4526        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4527    {
4528        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4529        cursor.seek(&DimensionPair { key, value: None });
4530        if let Some(region) = cursor.region() {
4531            if key >= region.range.end.key {
4532                return region.range.end.value.unwrap();
4533            }
4534            let start_key = region.range.start.key;
4535            let start_value = region.range.start.value.unwrap();
4536            let buffer_start_key = region.buffer_range.start.key;
4537            let buffer_start_value = region.buffer_range.start.value.unwrap();
4538            let mut buffer_key = buffer_start_key;
4539            buffer_key += key - start_key;
4540            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4541            let mut result = start_value;
4542            result += buffer_value - buffer_start_value;
4543            result
4544        } else {
4545            self.max_position()
4546        }
4547    }
4548
4549    pub fn point_to_buffer_offset<T: ToOffset>(
4550        &self,
4551        point: T,
4552    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4553        let offset = point.to_offset(self);
4554        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4555        cursor.seek(&offset);
4556        let region = cursor.region()?;
4557        let overshoot = offset - region.range.start;
4558        let buffer_offset = region.buffer_range.start + overshoot;
4559        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4560            && region.has_trailing_newline
4561            && !region.is_main_buffer
4562        {
4563            let main_buffer_position = cursor.main_buffer_position()?;
4564            let buffer_snapshot = &cursor.excerpt()?.buffer;
4565            return Some((buffer_snapshot, main_buffer_position));
4566        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4567            return None;
4568        }
4569        Some((region.buffer, buffer_offset))
4570    }
4571
4572    pub fn point_to_buffer_point(
4573        &self,
4574        point: Point,
4575    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4576        let mut cursor = self.cursor::<Point, Point>();
4577        cursor.seek(&point);
4578        let region = cursor.region()?;
4579        let overshoot = point - region.range.start;
4580        let buffer_point = region.buffer_range.start + overshoot;
4581        let excerpt = cursor.excerpt()?;
4582        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4583            && region.has_trailing_newline
4584            && !region.is_main_buffer
4585        {
4586            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4587        } else if buffer_point > region.buffer.max_point() {
4588            return None;
4589        }
4590        Some((region.buffer, buffer_point, excerpt.id))
4591    }
4592
4593    pub fn suggested_indents(
4594        &self,
4595        rows: impl IntoIterator<Item = u32>,
4596        cx: &App,
4597    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4598        let mut result = BTreeMap::new();
4599
4600        let mut rows_for_excerpt = Vec::new();
4601        let mut cursor = self.cursor::<Point, Point>();
4602        let mut rows = rows.into_iter().peekable();
4603        let mut prev_row = u32::MAX;
4604        let mut prev_language_indent_size = IndentSize::default();
4605
4606        while let Some(row) = rows.next() {
4607            cursor.seek(&Point::new(row, 0));
4608            let Some(region) = cursor.region() else {
4609                continue;
4610            };
4611
4612            // Retrieve the language and indent size once for each disjoint region being indented.
4613            let single_indent_size = if row.saturating_sub(1) == prev_row {
4614                prev_language_indent_size
4615            } else {
4616                region
4617                    .buffer
4618                    .language_indent_size_at(Point::new(row, 0), cx)
4619            };
4620            prev_language_indent_size = single_indent_size;
4621            prev_row = row;
4622
4623            let start_buffer_row = region.buffer_range.start.row;
4624            let start_multibuffer_row = region.range.start.row;
4625            let end_multibuffer_row = region.range.end.row;
4626
4627            rows_for_excerpt.push(row);
4628            while let Some(next_row) = rows.peek().copied() {
4629                if end_multibuffer_row > next_row {
4630                    rows_for_excerpt.push(next_row);
4631                    rows.next();
4632                } else {
4633                    break;
4634                }
4635            }
4636
4637            let buffer_rows = rows_for_excerpt
4638                .drain(..)
4639                .map(|row| start_buffer_row + row - start_multibuffer_row);
4640            let buffer_indents = region
4641                .buffer
4642                .suggested_indents(buffer_rows, single_indent_size);
4643            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4644                (
4645                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4646                    indent,
4647                )
4648            });
4649            result.extend(multibuffer_indents);
4650        }
4651
4652        result
4653    }
4654
4655    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4656        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4657            let mut size = buffer.indent_size_for_line(range.start.row);
4658            size.len = size
4659                .len
4660                .min(range.end.column)
4661                .saturating_sub(range.start.column);
4662            size
4663        } else {
4664            IndentSize::spaces(0)
4665        }
4666    }
4667
4668    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4669        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4670            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4671        } else {
4672            LineIndent::spaces(0)
4673        }
4674    }
4675
4676    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4677        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4678
4679        if self.language_settings(cx).extend_comment_on_newline
4680            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4681        {
4682            let delimiters = language_scope.line_comment_prefixes();
4683            for delimiter in delimiters {
4684                if *self
4685                    .chars_at(Point::new(row.0, indent.len() as u32))
4686                    .take(delimiter.chars().count())
4687                    .collect::<String>()
4688                    .as_str()
4689                    == **delimiter
4690                {
4691                    indent.push_str(delimiter);
4692                    break;
4693                }
4694            }
4695        }
4696
4697        indent
4698    }
4699
4700    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4701    where
4702        T: ToOffset,
4703    {
4704        for char in self.reversed_chars_at(position) {
4705            if !char.is_whitespace() {
4706                return false;
4707            }
4708            if char == '\n' {
4709                return true;
4710            }
4711        }
4712        true
4713    }
4714
4715    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4716        while row.0 > 0 {
4717            row.0 -= 1;
4718            if !self.is_line_blank(row) {
4719                return Some(row);
4720            }
4721        }
4722        None
4723    }
4724
4725    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4726        if let Some((_, range)) = self.buffer_line_for_row(row) {
4727            range.end.column - range.start.column
4728        } else {
4729            0
4730        }
4731    }
4732
4733    pub fn buffer_line_for_row(
4734        &self,
4735        row: MultiBufferRow,
4736    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4737        let mut cursor = self.cursor::<Point, Point>();
4738        let point = Point::new(row.0, 0);
4739        cursor.seek(&point);
4740        let region = cursor.region()?;
4741        let overshoot = point.min(region.range.end) - region.range.start;
4742        let buffer_point = region.buffer_range.start + overshoot;
4743        if buffer_point.row > region.buffer_range.end.row {
4744            return None;
4745        }
4746        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4747        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4748            .min(region.buffer_range.end);
4749        Some((region.buffer, line_start..line_end))
4750    }
4751
4752    pub fn max_point(&self) -> Point {
4753        self.text_summary().lines
4754    }
4755
4756    pub fn max_row(&self) -> MultiBufferRow {
4757        MultiBufferRow(self.text_summary().lines.row)
4758    }
4759
4760    pub fn text_summary(&self) -> MBTextSummary {
4761        self.diff_transforms.summary().output
4762    }
4763
4764    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4765    where
4766        MBD: MultiBufferDimension + AddAssign,
4767        O: ToOffset,
4768    {
4769        let range = range.start.to_offset(self)..range.end.to_offset(self);
4770        let mut cursor = self
4771            .diff_transforms
4772            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4773        cursor.seek(&range.start, Bias::Right);
4774
4775        let Some(first_transform) = cursor.item() else {
4776            return MBD::from_summary(&MBTextSummary::default());
4777        };
4778
4779        let diff_transform_start = cursor.start().0;
4780        let diff_transform_end = cursor.end().0;
4781        let diff_start = range.start;
4782        let start_overshoot = diff_start - diff_transform_start;
4783        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4784
4785        let mut result = match first_transform {
4786            DiffTransform::BufferContent { .. } => {
4787                let excerpt_start = cursor.start().1 + start_overshoot;
4788                let excerpt_end = cursor.start().1 + end_overshoot;
4789                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4790            }
4791            DiffTransform::DeletedHunk {
4792                buffer_id,
4793                base_text_byte_range,
4794                has_trailing_newline,
4795                ..
4796            } => {
4797                let buffer_start = base_text_byte_range.start + start_overshoot;
4798                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4799                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4800                    panic!("{:?} is in non-existent deleted hunk", range.start)
4801                };
4802
4803                let include_trailing_newline =
4804                    *has_trailing_newline && range.end >= diff_transform_end;
4805                if include_trailing_newline {
4806                    buffer_end -= 1;
4807                }
4808
4809                let mut summary = base_text
4810                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4811
4812                if include_trailing_newline {
4813                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4814                        &TextSummary::newline(),
4815                    ))
4816                }
4817
4818                let mut result = MBD::default();
4819                result.add_text_dim(&summary);
4820                result
4821            }
4822        };
4823        if range.end < diff_transform_end {
4824            return result;
4825        }
4826
4827        cursor.next();
4828        result.add_mb_text_summary(
4829            &cursor
4830                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4831                .0,
4832        );
4833
4834        let Some(last_transform) = cursor.item() else {
4835            return result;
4836        };
4837
4838        let overshoot = range.end - cursor.start().0;
4839        let suffix = match last_transform {
4840            DiffTransform::BufferContent { .. } => {
4841                let end = cursor.start().1 + overshoot;
4842                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4843            }
4844            DiffTransform::DeletedHunk {
4845                base_text_byte_range,
4846                buffer_id,
4847                has_trailing_newline,
4848                ..
4849            } => {
4850                let buffer_end = base_text_byte_range.start + overshoot;
4851                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4852                    panic!("{:?} is in non-existent deleted hunk", range.end)
4853                };
4854
4855                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4856                    base_text_byte_range.start..buffer_end,
4857                );
4858                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4859                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4860                        &TextSummary::from("\n"),
4861                    ))
4862                }
4863
4864                let mut result = MBD::default();
4865                result.add_text_dim(&suffix);
4866                result
4867            }
4868        };
4869
4870        result += suffix;
4871        result
4872    }
4873
4874    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4875    where
4876        MBD: MultiBufferDimension + AddAssign,
4877    {
4878        let mut summary = MBD::default();
4879        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4880        cursor.seek(&range.start, Bias::Right);
4881        if let Some(excerpt) = cursor.item() {
4882            let mut end_before_newline = cursor.end();
4883            if excerpt.has_trailing_newline {
4884                end_before_newline -= 1;
4885            }
4886
4887            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4888            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4889            let end_in_excerpt =
4890                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4891            summary.add_text_dim(
4892                &excerpt
4893                    .buffer
4894                    .text_summary_for_range::<MBD::TextDimension, _>(
4895                        start_in_excerpt..end_in_excerpt,
4896                    ),
4897            );
4898
4899            if range.end > end_before_newline {
4900                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4901            }
4902
4903            cursor.next();
4904        }
4905
4906        if range.end > *cursor.start() {
4907            summary += cursor
4908                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4909                .0;
4910            if let Some(excerpt) = cursor.item() {
4911                range.end = cmp::max(*cursor.start(), range.end);
4912
4913                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4914                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4915                summary.add_text_dim(
4916                    &excerpt
4917                        .buffer
4918                        .text_summary_for_range::<MBD::TextDimension, _>(
4919                            excerpt_start..end_in_excerpt,
4920                        ),
4921                );
4922            }
4923        }
4924
4925        summary
4926    }
4927
4928    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4929    where
4930        MBD: MultiBufferDimension
4931            + Ord
4932            + Sub<Output = MBD::TextDimension>
4933            + AddAssign<MBD::TextDimension>,
4934        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4935    {
4936        self.summaries_for_anchors([anchor])[0]
4937    }
4938
4939    fn resolve_summary_for_anchor<MBD>(
4940        &self,
4941        anchor: &Anchor,
4942        excerpt_position: ExcerptDimension<MBD>,
4943        diff_transforms: &mut Cursor<
4944            DiffTransform,
4945            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4946        >,
4947    ) -> MBD
4948    where
4949        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4950    {
4951        loop {
4952            let transform_end_position = diff_transforms.end().0;
4953            let at_transform_end =
4954                transform_end_position == excerpt_position && diff_transforms.item().is_some();
4955            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4956                diff_transforms.next();
4957                continue;
4958            }
4959
4960            let mut position = diff_transforms.start().1;
4961            match diff_transforms.item() {
4962                Some(DiffTransform::DeletedHunk {
4963                    buffer_id,
4964                    base_text_byte_range,
4965                    ..
4966                }) => {
4967                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4968                        && let Some(base_text) =
4969                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4970                        && diff_base_anchor.is_valid(&base_text)
4971                    {
4972                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4973                        if base_text_offset >= base_text_byte_range.start
4974                            && base_text_offset <= base_text_byte_range.end
4975                        {
4976                            let position_in_hunk = base_text
4977                                .text_summary_for_range::<MBD::TextDimension, _>(
4978                                    base_text_byte_range.start..base_text_offset,
4979                                );
4980                            position.0.add_text_dim(&position_in_hunk);
4981                        } else if at_transform_end {
4982                            diff_transforms.next();
4983                            continue;
4984                        }
4985                    }
4986                }
4987                _ => {
4988                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4989                        diff_transforms.next();
4990                        continue;
4991                    }
4992                    let overshoot = excerpt_position - diff_transforms.start().0;
4993                    position += overshoot;
4994                }
4995            }
4996
4997            return position.0;
4998        }
4999    }
5000
5001    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5002        let mut cursor = self
5003            .excerpts
5004            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5005        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5006
5007        cursor.seek(&Some(locator), Bias::Left);
5008        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5009            cursor.prev();
5010        }
5011
5012        let mut position = cursor.start().1;
5013        if let Some(excerpt) = cursor.item()
5014            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5015        {
5016            let excerpt_buffer_start = excerpt
5017                .buffer
5018                .offset_for_anchor(&excerpt.range.context.start);
5019            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5020            let buffer_position = cmp::min(
5021                excerpt_buffer_end,
5022                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5023            );
5024            if buffer_position > excerpt_buffer_start {
5025                position += buffer_position - excerpt_buffer_start;
5026            }
5027        }
5028        position
5029    }
5030
5031    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5032        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5033            excerpt_id = *replacement;
5034        }
5035        excerpt_id
5036    }
5037
5038    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5039    where
5040        MBD: MultiBufferDimension
5041            + Ord
5042            + Sub<Output = MBD::TextDimension>
5043            + AddAssign<MBD::TextDimension>,
5044        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5045        I: 'a + IntoIterator<Item = &'a Anchor>,
5046    {
5047        let mut anchors = anchors.into_iter().peekable();
5048        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5049        let mut diff_transforms_cursor = self
5050            .diff_transforms
5051            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5052        diff_transforms_cursor.next();
5053
5054        let mut summaries = Vec::new();
5055        while let Some(anchor) = anchors.peek() {
5056            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5057
5058            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5059                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5060            });
5061
5062            let locator = self.excerpt_locator_for_id(excerpt_id);
5063            cursor.seek_forward(locator, Bias::Left);
5064            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5065                cursor.prev();
5066            }
5067
5068            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5069            if let Some(excerpt) = cursor.item() {
5070                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5071                    let position = self.resolve_summary_for_anchor(
5072                        &Anchor::min(),
5073                        excerpt_start_position,
5074                        &mut diff_transforms_cursor,
5075                    );
5076                    summaries.extend(excerpt_anchors.map(|_| position));
5077                    continue;
5078                }
5079                let excerpt_buffer_start = excerpt
5080                    .range
5081                    .context
5082                    .start
5083                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5084                let excerpt_buffer_end = excerpt
5085                    .range
5086                    .context
5087                    .end
5088                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5089                for (buffer_summary, anchor) in excerpt
5090                    .buffer
5091                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5092                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5093                    )
5094                {
5095                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5096                    let mut position = excerpt_start_position;
5097                    if summary > excerpt_buffer_start {
5098                        position += summary - excerpt_buffer_start;
5099                    }
5100
5101                    if diff_transforms_cursor.start().0 < position {
5102                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5103                    }
5104
5105                    summaries.push(self.resolve_summary_for_anchor(
5106                        anchor,
5107                        position,
5108                        &mut diff_transforms_cursor,
5109                    ));
5110                }
5111            } else {
5112                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5113                let position = self.resolve_summary_for_anchor(
5114                    &Anchor::max(),
5115                    excerpt_start_position,
5116                    &mut diff_transforms_cursor,
5117                );
5118                summaries.extend(excerpt_anchors.map(|_| position));
5119            }
5120        }
5121
5122        summaries
5123    }
5124
5125    pub fn dimensions_from_points<'a, MBD>(
5126        &'a self,
5127        points: impl 'a + IntoIterator<Item = Point>,
5128    ) -> impl 'a + Iterator<Item = MBD>
5129    where
5130        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5131    {
5132        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5133        cursor.seek(&DimensionPair {
5134            key: Point::default(),
5135            value: None,
5136        });
5137        let mut points = points.into_iter();
5138        iter::from_fn(move || {
5139            let point = points.next()?;
5140
5141            cursor.seek_forward(&DimensionPair {
5142                key: point,
5143                value: None,
5144            });
5145
5146            if let Some(region) = cursor.region() {
5147                let overshoot = point - region.range.start.key;
5148                let buffer_point = region.buffer_range.start + overshoot;
5149                let mut position = region.range.start.value.unwrap();
5150                position.add_text_dim(
5151                    &region
5152                        .buffer
5153                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5154                );
5155                if point == region.range.end.key && region.has_trailing_newline {
5156                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5157                }
5158                Some(position)
5159            } else {
5160                Some(MBD::from_summary(&self.text_summary()))
5161            }
5162        })
5163    }
5164
5165    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5166    where
5167        I: 'a + IntoIterator<Item = &'a Anchor>,
5168    {
5169        let mut anchors = anchors.into_iter().enumerate().peekable();
5170        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5171        cursor.next();
5172
5173        let mut result = Vec::new();
5174
5175        while let Some((_, anchor)) = anchors.peek() {
5176            let old_excerpt_id = anchor.excerpt_id;
5177
5178            // Find the location where this anchor's excerpt should be.
5179            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5180            cursor.seek_forward(&Some(old_locator), Bias::Left);
5181
5182            let next_excerpt = cursor.item();
5183            let prev_excerpt = cursor.prev_item();
5184
5185            // Process all of the anchors for this excerpt.
5186            while let Some((anchor_ix, &anchor)) =
5187                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5188            {
5189                let mut anchor = anchor;
5190
5191                // Leave min and max anchors unchanged if invalid or
5192                // if the old excerpt still exists at this location
5193                let mut kept_position = next_excerpt
5194                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5195                    || old_excerpt_id == ExcerptId::max()
5196                    || old_excerpt_id == ExcerptId::min();
5197
5198                // If the old excerpt no longer exists at this location, then attempt to
5199                // find an equivalent position for this anchor in an adjacent excerpt.
5200                if !kept_position {
5201                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5202                        if excerpt.contains(&anchor) {
5203                            anchor.excerpt_id = excerpt.id;
5204                            kept_position = true;
5205                            break;
5206                        }
5207                    }
5208                }
5209
5210                // If there's no adjacent excerpt that contains the anchor's position,
5211                // then report that the anchor has lost its position.
5212                if !kept_position {
5213                    anchor = if let Some(excerpt) = next_excerpt {
5214                        let mut text_anchor = excerpt
5215                            .range
5216                            .context
5217                            .start
5218                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5219                        if text_anchor
5220                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5221                            .is_gt()
5222                        {
5223                            text_anchor = excerpt.range.context.end;
5224                        }
5225                        Anchor::in_buffer(excerpt.id, text_anchor)
5226                    } else if let Some(excerpt) = prev_excerpt {
5227                        let mut text_anchor = excerpt
5228                            .range
5229                            .context
5230                            .end
5231                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5232                        if text_anchor
5233                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5234                            .is_lt()
5235                        {
5236                            text_anchor = excerpt.range.context.start;
5237                        }
5238                        Anchor::in_buffer(excerpt.id, text_anchor)
5239                    } else if anchor.text_anchor.bias == Bias::Left {
5240                        Anchor::min()
5241                    } else {
5242                        Anchor::max()
5243                    };
5244                }
5245
5246                result.push((anchor_ix, anchor, kept_position));
5247            }
5248        }
5249        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5250        result
5251    }
5252
5253    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5254        self.anchor_at(position, Bias::Left)
5255    }
5256
5257    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5258        self.anchor_at(position, Bias::Right)
5259    }
5260
5261    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5262        let offset = position.to_offset(self);
5263
5264        // Find the given position in the diff transforms. Determine the corresponding
5265        // offset in the excerpts, and whether the position is within a deleted hunk.
5266        let mut diff_transforms = self
5267            .diff_transforms
5268            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5269        diff_transforms.seek(&offset, Bias::Right);
5270
5271        if offset == diff_transforms.start().0
5272            && bias == Bias::Left
5273            && let Some(prev_item) = diff_transforms.prev_item()
5274            && let DiffTransform::DeletedHunk { .. } = prev_item
5275        {
5276            diff_transforms.prev();
5277        }
5278        let offset_in_transform = offset - diff_transforms.start().0;
5279        let mut excerpt_offset = diff_transforms.start().1;
5280        let mut diff_base_anchor = None;
5281        if let Some(DiffTransform::DeletedHunk {
5282            buffer_id,
5283            base_text_byte_range,
5284            has_trailing_newline,
5285            ..
5286        }) = diff_transforms.item()
5287        {
5288            let diff = self.diffs.get(buffer_id).expect("missing diff");
5289            if offset_in_transform > base_text_byte_range.len() {
5290                debug_assert!(*has_trailing_newline);
5291                bias = Bias::Right;
5292            } else {
5293                diff_base_anchor = Some(
5294                    diff.base_text()
5295                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5296                );
5297                bias = Bias::Left;
5298            }
5299        } else {
5300            excerpt_offset += MultiBufferOffset(offset_in_transform);
5301        };
5302
5303        let mut excerpts = self
5304            .excerpts
5305            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5306        excerpts.seek(&excerpt_offset, Bias::Right);
5307        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5308            excerpts.prev();
5309        }
5310        if let Some(excerpt) = excerpts.item() {
5311            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5312            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5313                overshoot -= 1;
5314                bias = Bias::Right;
5315            }
5316
5317            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5318            let text_anchor =
5319                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5320            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5321            match diff_base_anchor {
5322                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5323                None => anchor,
5324            }
5325        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5326        {
5327            Anchor::min()
5328        } else {
5329            Anchor::max()
5330        }
5331    }
5332
5333    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5334    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5335        let (excerpt, buffer, _) = self.as_singleton()?;
5336        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5337            Some(Anchor::in_buffer(*excerpt, text_anchor))
5338        } else {
5339            None
5340        }
5341    }
5342
5343    /// Returns an anchor for the given excerpt and text anchor,
5344    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5345    pub fn anchor_range_in_excerpt(
5346        &self,
5347        excerpt_id: ExcerptId,
5348        text_anchor: Range<text::Anchor>,
5349    ) -> Option<Range<Anchor>> {
5350        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5351
5352        Some(
5353            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5354                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5355        )
5356    }
5357
5358    /// Returns an anchor for the given excerpt and text anchor,
5359    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5360    pub fn anchor_in_excerpt(
5361        &self,
5362        excerpt_id: ExcerptId,
5363        text_anchor: text::Anchor,
5364    ) -> Option<Anchor> {
5365        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5366        Self::anchor_in_excerpt_(excerpt, text_anchor)
5367    }
5368
5369    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5370    pub fn anchors_in_excerpt(
5371        &self,
5372        excerpt_id: ExcerptId,
5373        text_anchors: impl IntoIterator<Item = text::Anchor>,
5374    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5375        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5376        Some(
5377            text_anchors
5378                .into_iter()
5379                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5380        )
5381    }
5382
5383    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5384        match text_anchor.buffer_id {
5385            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5386            Some(_) => return None,
5387            None if text_anchor.is_max() || text_anchor.is_min() => {
5388                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5389            }
5390            None => return None,
5391        }
5392
5393        let context = &excerpt.range.context;
5394        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5395            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5396        {
5397            return None;
5398        }
5399
5400        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5401    }
5402
5403    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5404        Some(self.excerpt(excerpt_id)?.range.context.clone())
5405    }
5406
5407    pub fn excerpt_range_for_excerpt(
5408        &self,
5409        excerpt_id: ExcerptId,
5410    ) -> Option<ExcerptRange<text::Anchor>> {
5411        Some(self.excerpt(excerpt_id)?.range.clone())
5412    }
5413
5414    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5415        if anchor.is_min() || anchor.is_max() {
5416            // todo(lw): should be `!self.is_empty()`
5417            true
5418        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5419            excerpt.buffer.can_resolve(&anchor.text_anchor)
5420        } else {
5421            false
5422        }
5423    }
5424
5425    pub fn excerpts(
5426        &self,
5427    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5428        self.excerpts
5429            .iter()
5430            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5431    }
5432
5433    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5434    where
5435        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5436        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5437    {
5438        let excerpts = self.excerpts.cursor(());
5439        let diff_transforms = self.diff_transforms.cursor(());
5440        MultiBufferCursor {
5441            excerpts,
5442            diff_transforms,
5443            diffs: &self.diffs,
5444            cached_region: None,
5445        }
5446    }
5447
5448    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5449        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5450        let mut excerpts = self
5451            .excerpts
5452            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5453        excerpts.seek(&Some(start_locator), Bias::Left);
5454        excerpts.prev();
5455
5456        let mut diff_transforms = self
5457            .diff_transforms
5458            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5459        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5460        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5461            diff_transforms.next();
5462        }
5463
5464        let excerpt = excerpts.item()?;
5465        Some(MultiBufferExcerpt {
5466            excerpt,
5467            offset: diff_transforms.start().output_dimension.0,
5468            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5469            excerpt_offset: excerpts.start().1,
5470            diff_transforms,
5471        })
5472    }
5473
5474    pub fn excerpt_boundaries_in_range<R, T>(
5475        &self,
5476        range: R,
5477    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5478    where
5479        R: RangeBounds<T>,
5480        T: ToOffset,
5481    {
5482        let start_offset;
5483        let start = match range.start_bound() {
5484            Bound::Included(start) => {
5485                start_offset = start.to_offset(self);
5486                Bound::Included(start_offset)
5487            }
5488            Bound::Excluded(_) => {
5489                panic!("not supported")
5490            }
5491            Bound::Unbounded => {
5492                start_offset = MultiBufferOffset::ZERO;
5493                Bound::Unbounded
5494            }
5495        };
5496        let end = match range.end_bound() {
5497            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5498            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5499            Bound::Unbounded => Bound::Unbounded,
5500        };
5501        let bounds = (start, end);
5502        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5503        cursor.seek(&DimensionPair {
5504            key: start_offset,
5505            value: None,
5506        });
5507
5508        if cursor
5509            .region()
5510            .is_some_and(|region| bounds.contains(&region.range.start.key))
5511        {
5512            cursor.prev_excerpt();
5513        } else {
5514            cursor.seek_to_start_of_current_excerpt();
5515        }
5516        let mut prev_region = cursor.region();
5517
5518        cursor.next_excerpt();
5519
5520        iter::from_fn(move || {
5521            loop {
5522                if self.singleton {
5523                    return None;
5524                }
5525
5526                let next_region = cursor.region()?;
5527                cursor.next_excerpt();
5528                if !bounds.contains(&next_region.range.start.key) {
5529                    prev_region = Some(next_region);
5530                    continue;
5531                }
5532
5533                let next_region_start = next_region.range.start.value.unwrap();
5534                let next_region_end = if let Some(region) = cursor.region() {
5535                    region.range.start.value.unwrap()
5536                } else {
5537                    self.max_point()
5538                };
5539
5540                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5541                    id: region.excerpt.id,
5542                    buffer: region.excerpt.buffer.clone(),
5543                    buffer_id: region.excerpt.buffer_id,
5544                    range: region.excerpt.range.clone(),
5545                    end_row: MultiBufferRow(next_region_start.row),
5546                });
5547
5548                let next = ExcerptInfo {
5549                    id: next_region.excerpt.id,
5550                    buffer: next_region.excerpt.buffer.clone(),
5551                    buffer_id: next_region.excerpt.buffer_id,
5552                    range: next_region.excerpt.range.clone(),
5553                    end_row: if next_region.excerpt.has_trailing_newline {
5554                        MultiBufferRow(next_region_end.row - 1)
5555                    } else {
5556                        MultiBufferRow(next_region_end.row)
5557                    },
5558                };
5559
5560                let row = MultiBufferRow(next_region_start.row);
5561
5562                prev_region = Some(next_region);
5563
5564                return Some(ExcerptBoundary { row, prev, next });
5565            }
5566        })
5567    }
5568
5569    pub fn edit_count(&self) -> usize {
5570        self.edit_count
5571    }
5572
5573    pub fn non_text_state_update_count(&self) -> usize {
5574        self.non_text_state_update_count
5575    }
5576
5577    /// Returns the smallest enclosing bracket ranges containing the given range or
5578    /// None if no brackets contain range or the range is not contained in a single
5579    /// excerpt
5580    ///
5581    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5582    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5583        &self,
5584        range: Range<T>,
5585        range_filter: Option<
5586            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5587        >,
5588    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5589        let range = range.start.to_offset(self)..range.end.to_offset(self);
5590        let mut excerpt = self.excerpt_containing(range.clone())?;
5591        let buffer = excerpt.buffer();
5592        let excerpt_buffer_range = excerpt.buffer_range();
5593
5594        // Filter to ranges contained in the excerpt
5595        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5596            excerpt_buffer_range.contains(&BufferOffset(open.start))
5597                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5598                && range_filter.is_none_or(|filter| {
5599                    filter(
5600                        buffer,
5601                        BufferOffset(open.start)..BufferOffset(close.end),
5602                        BufferOffset(close.start)..BufferOffset(close.end),
5603                    )
5604                })
5605        };
5606
5607        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5608            excerpt.map_range_to_buffer(range),
5609            Some(&range_filter),
5610        )?;
5611
5612        Some((
5613            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5614            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5615        ))
5616    }
5617
5618    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5619    /// not contained in a single excerpt
5620    pub fn enclosing_bracket_ranges<T: ToOffset>(
5621        &self,
5622        range: Range<T>,
5623    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5624    {
5625        let range = range.start.to_offset(self)..range.end.to_offset(self);
5626        let mut excerpt = self.excerpt_containing(range.clone())?;
5627
5628        Some(
5629            excerpt
5630                .buffer()
5631                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5632                .filter_map(move |pair| {
5633                    let open_range =
5634                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5635                    let close_range =
5636                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5637                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5638                        Some((
5639                            excerpt.map_range_from_buffer(open_range),
5640                            excerpt.map_range_from_buffer(close_range),
5641                        ))
5642                    } else {
5643                        None
5644                    }
5645                }),
5646        )
5647    }
5648
5649    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5650    /// not contained in a single excerpt
5651    pub fn text_object_ranges<T: ToOffset>(
5652        &self,
5653        range: Range<T>,
5654        options: TreeSitterOptions,
5655    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5656        let range = range.start.to_offset(self)..range.end.to_offset(self);
5657        self.excerpt_containing(range.clone())
5658            .map(|mut excerpt| {
5659                excerpt
5660                    .buffer()
5661                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5662                    .filter_map(move |(range, text_object)| {
5663                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5664                        if excerpt.contains_buffer_range(range.clone()) {
5665                            Some((excerpt.map_range_from_buffer(range), text_object))
5666                        } else {
5667                            None
5668                        }
5669                    })
5670            })
5671            .into_iter()
5672            .flatten()
5673    }
5674
5675    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5676    /// not contained in a single excerpt
5677    pub fn bracket_ranges<T: ToOffset>(
5678        &self,
5679        range: Range<T>,
5680    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5681    {
5682        let range = range.start.to_offset(self)..range.end.to_offset(self);
5683        let mut excerpt = self.excerpt_containing(range.clone())?;
5684        Some(
5685            excerpt
5686                .buffer()
5687                .bracket_ranges(excerpt.map_range_to_buffer(range))
5688                .filter_map(move |pair| {
5689                    let open_range =
5690                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5691                    let close_range =
5692                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5693                    excerpt
5694                        .contains_buffer_range(open_range.start..close_range.end)
5695                        .then(|| BracketMatch {
5696                            open_range: excerpt.map_range_from_buffer(open_range),
5697                            close_range: excerpt.map_range_from_buffer(close_range),
5698                            color_index: pair.color_index,
5699                            newline_only: pair.newline_only,
5700                            syntax_layer_depth: pair.syntax_layer_depth,
5701                        })
5702                })
5703                .map(BracketMatch::bracket_ranges),
5704        )
5705    }
5706
5707    pub fn redacted_ranges<'a, T: ToOffset>(
5708        &'a self,
5709        range: Range<T>,
5710        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5711    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5712        let range = range.start.to_offset(self)..range.end.to_offset(self);
5713        self.lift_buffer_metadata(range, move |buffer, range| {
5714            if redaction_enabled(buffer.file()) {
5715                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5716            } else {
5717                None
5718            }
5719        })
5720        .map(|(range, _, _)| range)
5721    }
5722
5723    pub fn runnable_ranges(
5724        &self,
5725        range: Range<Anchor>,
5726    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5727        let range = range.start.to_offset(self)..range.end.to_offset(self);
5728        self.lift_buffer_metadata(range, move |buffer, range| {
5729            Some(
5730                buffer
5731                    .runnable_ranges(range.clone())
5732                    .filter(move |runnable| {
5733                        runnable.run_range.start >= range.start
5734                            && runnable.run_range.end < range.end
5735                    })
5736                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5737            )
5738        })
5739        .map(|(run_range, runnable, _)| (run_range, runnable))
5740    }
5741
5742    pub fn line_indents(
5743        &self,
5744        start_row: MultiBufferRow,
5745        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5746    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5747        let max_point = self.max_point();
5748        let mut cursor = self.cursor::<Point, Point>();
5749        cursor.seek(&Point::new(start_row.0, 0));
5750        iter::from_fn(move || {
5751            let mut region = cursor.region()?;
5752            while !buffer_filter(&region.excerpt.buffer) {
5753                cursor.next();
5754                region = cursor.region()?;
5755            }
5756            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5757            let buffer_start_row =
5758                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5759
5760            let buffer_end_row = if region.is_main_buffer
5761                && (region.has_trailing_newline || region.range.end == max_point)
5762            {
5763                region.buffer_range.end.row
5764            } else {
5765                region.buffer_range.end.row.saturating_sub(1)
5766            };
5767
5768            let line_indents = region
5769                .buffer
5770                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5771            cursor.next();
5772            Some(line_indents.map(move |(buffer_row, indent)| {
5773                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5774                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5775            }))
5776        })
5777        .flatten()
5778    }
5779
5780    pub fn reversed_line_indents(
5781        &self,
5782        end_row: MultiBufferRow,
5783        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5784    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5785        let max_point = self.max_point();
5786        let mut cursor = self.cursor::<Point, Point>();
5787        cursor.seek(&Point::new(end_row.0, 0));
5788        iter::from_fn(move || {
5789            let mut region = cursor.region()?;
5790            while !buffer_filter(&region.excerpt.buffer) {
5791                cursor.prev();
5792                region = cursor.region()?;
5793            }
5794
5795            let buffer_start_row = region.buffer_range.start.row;
5796            let buffer_end_row = if region.is_main_buffer
5797                && (region.has_trailing_newline || region.range.end == max_point)
5798            {
5799                region.buffer_range.end.row + 1
5800            } else {
5801                region.buffer_range.end.row
5802            };
5803
5804            let overshoot = end_row.0 - region.range.start.row;
5805            let buffer_end_row =
5806                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5807
5808            let line_indents = region
5809                .buffer
5810                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5811            cursor.prev();
5812            Some(line_indents.map(move |(buffer_row, indent)| {
5813                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5814                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5815            }))
5816        })
5817        .flatten()
5818    }
5819
5820    pub async fn enclosing_indent(
5821        &self,
5822        mut target_row: MultiBufferRow,
5823    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5824        let max_row = MultiBufferRow(self.max_point().row);
5825        if target_row >= max_row {
5826            return None;
5827        }
5828
5829        let mut target_indent = self.line_indent_for_row(target_row);
5830
5831        // If the current row is at the start of an indented block, we want to return this
5832        // block as the enclosing indent.
5833        if !target_indent.is_line_empty() && target_row < max_row {
5834            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5835            if !next_line_indent.is_line_empty()
5836                && target_indent.raw_len() < next_line_indent.raw_len()
5837            {
5838                target_indent = next_line_indent;
5839                target_row.0 += 1;
5840            }
5841        }
5842
5843        const SEARCH_ROW_LIMIT: u32 = 25000;
5844        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5845        const YIELD_INTERVAL: u32 = 100;
5846
5847        let mut accessed_row_counter = 0;
5848
5849        // If there is a blank line at the current row, search for the next non indented lines
5850        if target_indent.is_line_empty() {
5851            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5852            let end =
5853                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5854
5855            let mut non_empty_line_above = None;
5856            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5857                if row < start {
5858                    break;
5859                }
5860                accessed_row_counter += 1;
5861                if accessed_row_counter == YIELD_INTERVAL {
5862                    accessed_row_counter = 0;
5863                    yield_now().await;
5864                }
5865                if !indent.is_line_empty() {
5866                    non_empty_line_above = Some((row, indent));
5867                    break;
5868                }
5869            }
5870
5871            let mut non_empty_line_below = None;
5872            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5873                if row > end {
5874                    break;
5875                }
5876                accessed_row_counter += 1;
5877                if accessed_row_counter == YIELD_INTERVAL {
5878                    accessed_row_counter = 0;
5879                    yield_now().await;
5880                }
5881                if !indent.is_line_empty() {
5882                    non_empty_line_below = Some((row, indent));
5883                    break;
5884                }
5885            }
5886
5887            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5888                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5889                    if above_indent.raw_len() >= below_indent.raw_len() {
5890                        (above_row, above_indent)
5891                    } else {
5892                        (below_row, below_indent)
5893                    }
5894                }
5895                (Some(above), None) => above,
5896                (None, Some(below)) => below,
5897                _ => return None,
5898            };
5899
5900            target_indent = indent;
5901            target_row = row;
5902        }
5903
5904        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5905        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5906
5907        let mut start_indent = None;
5908        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5909            if row < start {
5910                break;
5911            }
5912            accessed_row_counter += 1;
5913            if accessed_row_counter == YIELD_INTERVAL {
5914                accessed_row_counter = 0;
5915                yield_now().await;
5916            }
5917            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5918                start_indent = Some((row, indent));
5919                break;
5920            }
5921        }
5922        let (start_row, start_indent_size) = start_indent?;
5923
5924        let mut end_indent = (end, None);
5925        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5926            if row > end {
5927                break;
5928            }
5929            accessed_row_counter += 1;
5930            if accessed_row_counter == YIELD_INTERVAL {
5931                accessed_row_counter = 0;
5932                yield_now().await;
5933            }
5934            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5935                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5936                break;
5937            }
5938        }
5939        let (end_row, end_indent_size) = end_indent;
5940
5941        let indent = if let Some(end_indent_size) = end_indent_size {
5942            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5943                start_indent_size
5944            } else {
5945                end_indent_size
5946            }
5947        } else {
5948            start_indent_size
5949        };
5950
5951        Some((start_row..end_row, indent))
5952    }
5953
5954    pub fn indent_guides_in_range<T: ToPoint>(
5955        &self,
5956        range: Range<T>,
5957        ignore_disabled_for_language: bool,
5958        cx: &App,
5959    ) -> impl Iterator<Item = IndentGuide> {
5960        let range = range.start.to_point(self)..range.end.to_point(self);
5961        let start_row = MultiBufferRow(range.start.row);
5962        let end_row = MultiBufferRow(range.end.row);
5963
5964        let mut row_indents = self.line_indents(start_row, |buffer| {
5965            let settings =
5966                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5967            settings.indent_guides.enabled || ignore_disabled_for_language
5968        });
5969
5970        let mut result = Vec::new();
5971        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5972
5973        let mut prev_settings = None;
5974        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5975            if first_row > end_row {
5976                break;
5977            }
5978            let current_depth = indent_stack.len() as u32;
5979
5980            // Avoid retrieving the language settings repeatedly for every buffer row.
5981            if let Some((prev_buffer_id, _)) = &prev_settings
5982                && prev_buffer_id != &buffer.remote_id()
5983            {
5984                prev_settings.take();
5985            }
5986            let settings = &prev_settings
5987                .get_or_insert_with(|| {
5988                    (
5989                        buffer.remote_id(),
5990                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5991                    )
5992                })
5993                .1;
5994            let tab_size = settings.tab_size.get();
5995
5996            // When encountering empty, continue until found useful line indent
5997            // then add to the indent stack with the depth found
5998            let mut found_indent = false;
5999            let mut last_row = first_row;
6000            if line_indent.is_line_blank() {
6001                while !found_indent {
6002                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6003                        break;
6004                    };
6005                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6006                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6007                        break;
6008                    }
6009
6010                    if new_line_indent.is_line_blank() {
6011                        continue;
6012                    }
6013                    last_row = target_row.min(end_row);
6014                    line_indent = new_line_indent;
6015                    found_indent = true;
6016                    break;
6017                }
6018            } else {
6019                found_indent = true
6020            }
6021
6022            let depth = if found_indent {
6023                line_indent.len(tab_size) / tab_size
6024            } else {
6025                0
6026            };
6027
6028            match depth.cmp(&current_depth) {
6029                cmp::Ordering::Less => {
6030                    for _ in 0..(current_depth - depth) {
6031                        let mut indent = indent_stack.pop().unwrap();
6032                        if last_row != first_row {
6033                            // In this case, we landed on an empty row, had to seek forward,
6034                            // and discovered that the indent we where on is ending.
6035                            // This means that the last display row must
6036                            // be on line that ends this indent range, so we
6037                            // should display the range up to the first non-empty line
6038                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6039                        }
6040
6041                        result.push(indent)
6042                    }
6043                }
6044                cmp::Ordering::Greater => {
6045                    for next_depth in current_depth..depth {
6046                        indent_stack.push(IndentGuide {
6047                            buffer_id: buffer.remote_id(),
6048                            start_row: first_row,
6049                            end_row: last_row,
6050                            depth: next_depth,
6051                            tab_size,
6052                            settings: settings.indent_guides.clone(),
6053                        });
6054                    }
6055                }
6056                _ => {}
6057            }
6058
6059            for indent in indent_stack.iter_mut() {
6060                indent.end_row = last_row;
6061            }
6062        }
6063
6064        result.extend(indent_stack);
6065        result.into_iter()
6066    }
6067
6068    pub fn trailing_excerpt_update_count(&self) -> usize {
6069        self.trailing_excerpt_update_count
6070    }
6071
6072    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6073        self.point_to_buffer_offset(point)
6074            .and_then(|(buffer, _)| buffer.file())
6075    }
6076
6077    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6078        self.point_to_buffer_offset(offset)
6079            .and_then(|(buffer, offset)| buffer.language_at(offset))
6080    }
6081
6082    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6083        self.excerpts
6084            .first()
6085            .map(|excerpt| &excerpt.buffer)
6086            .map(|buffer| {
6087                language_settings(
6088                    buffer.language().map(|language| language.name()),
6089                    buffer.file(),
6090                    cx,
6091                )
6092            })
6093            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6094    }
6095
6096    pub fn language_settings_at<'a, T: ToOffset>(
6097        &'a self,
6098        point: T,
6099        cx: &'a App,
6100    ) -> Cow<'a, LanguageSettings> {
6101        let mut language = None;
6102        let mut file = None;
6103        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6104            language = buffer.language_at(offset);
6105            file = buffer.file();
6106        }
6107        language_settings(language.map(|l| l.name()), file, cx)
6108    }
6109
6110    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6111        self.point_to_buffer_offset(point)
6112            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6113    }
6114
6115    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6116        self.point_to_buffer_offset(point)
6117            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6118            .unwrap_or_default()
6119    }
6120
6121    pub fn language_indent_size_at<T: ToOffset>(
6122        &self,
6123        position: T,
6124        cx: &App,
6125    ) -> Option<IndentSize> {
6126        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6127        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6128    }
6129
6130    pub fn is_dirty(&self) -> bool {
6131        self.is_dirty
6132    }
6133
6134    pub fn has_deleted_file(&self) -> bool {
6135        self.has_deleted_file
6136    }
6137
6138    pub fn has_conflict(&self) -> bool {
6139        self.has_conflict
6140    }
6141
6142    pub fn has_diagnostics(&self) -> bool {
6143        self.excerpts
6144            .iter()
6145            .any(|excerpt| excerpt.buffer.has_diagnostics())
6146    }
6147
6148    pub fn diagnostic_group(
6149        &self,
6150        buffer_id: BufferId,
6151        group_id: usize,
6152    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6153        self.lift_buffer_metadata::<Point, _, _>(
6154            Point::zero()..self.max_point(),
6155            move |buffer, range| {
6156                if buffer.remote_id() != buffer_id {
6157                    return None;
6158                };
6159                Some(
6160                    buffer
6161                        .diagnostics_in_range(range, false)
6162                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6163                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6164                )
6165            },
6166        )
6167        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6168    }
6169
6170    pub fn diagnostics_in_range<'a, MBD>(
6171        &'a self,
6172        range: Range<MBD>,
6173    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6174    where
6175        MBD::TextDimension: 'a
6176            + text::ToOffset
6177            + text::FromAnchor
6178            + Sub<Output = MBD::TextDimension>
6179            + fmt::Debug
6180            + ops::Add<Output = MBD::TextDimension>
6181            + ops::AddAssign
6182            + Ord,
6183        MBD: MultiBufferDimension
6184            + Ord
6185            + Sub<Output = MBD::TextDimension>
6186            + ops::Add<MBD::TextDimension, Output = MBD>
6187            + ops::AddAssign<MBD::TextDimension>
6188            + 'a,
6189    {
6190        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6191            Some(
6192                buffer
6193                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6194                    .map(|entry| (entry.range, entry.diagnostic)),
6195            )
6196        })
6197        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6198    }
6199
6200    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6201        &'a self,
6202        range: Range<MBD>,
6203    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6204    where
6205        MBD: MultiBufferDimension
6206            + Ord
6207            + Sub<Output = MBD::TextDimension>
6208            + ops::Add<MBD::TextDimension, Output = MBD>
6209            + ops::AddAssign<MBD::TextDimension>,
6210        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6211            + ops::Add<Output = MBD::TextDimension>
6212            + text::ToOffset
6213            + text::FromAnchor
6214            + AddAssign<MBD::TextDimension>
6215            + Ord,
6216    {
6217        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6218            Some(
6219                buffer
6220                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6221                    .map(|entry| (entry.range, entry.diagnostic)),
6222            )
6223        })
6224        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6225    }
6226
6227    pub fn syntax_ancestor<T: ToOffset>(
6228        &self,
6229        range: Range<T>,
6230    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6231        let range = range.start.to_offset(self)..range.end.to_offset(self);
6232        let mut excerpt = self.excerpt_containing(range.clone())?;
6233        let node = excerpt
6234            .buffer()
6235            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6236        let node_range = node.byte_range();
6237        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6238        if !excerpt.contains_buffer_range(node_range.clone()) {
6239            return None;
6240        };
6241        Some((node, excerpt.map_range_from_buffer(node_range)))
6242    }
6243
6244    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6245        let (excerpt_id, _, buffer) = self.as_singleton()?;
6246        let outline = buffer.outline(theme);
6247        Some(Outline::new(
6248            outline
6249                .items
6250                .into_iter()
6251                .flat_map(|item| {
6252                    Some(OutlineItem {
6253                        depth: item.depth,
6254                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6255                        source_range_for_text: self
6256                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6257                        text: item.text,
6258                        highlight_ranges: item.highlight_ranges,
6259                        name_ranges: item.name_ranges,
6260                        body_range: item.body_range.and_then(|body_range| {
6261                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6262                        }),
6263                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6264                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6265                        }),
6266                    })
6267                })
6268                .collect(),
6269        ))
6270    }
6271
6272    pub fn symbols_containing<T: ToOffset>(
6273        &self,
6274        offset: T,
6275        theme: Option<&SyntaxTheme>,
6276    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6277        let anchor = self.anchor_before(offset);
6278        let excerpt @ &Excerpt {
6279            id: excerpt_id,
6280            buffer_id,
6281            ref buffer,
6282            ..
6283        } = self.excerpt(anchor.excerpt_id)?;
6284        if cfg!(debug_assertions) {
6285            match anchor.text_anchor.buffer_id {
6286                // we clearly are hitting this according to sentry, but in what situations can this occur?
6287                Some(anchor_buffer_id) => {
6288                    assert_eq!(
6289                        anchor_buffer_id, buffer_id,
6290                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6291                    )
6292                }
6293                None => assert!(anchor.is_max()),
6294            }
6295        };
6296        Some((
6297            buffer_id,
6298            buffer
6299                .symbols_containing(anchor.text_anchor, theme)
6300                .into_iter()
6301                .flat_map(|item| {
6302                    Some(OutlineItem {
6303                        depth: item.depth,
6304                        source_range_for_text: Anchor::range_in_buffer(
6305                            excerpt_id,
6306                            item.source_range_for_text,
6307                        ),
6308                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6309                        text: item.text,
6310                        highlight_ranges: item.highlight_ranges,
6311                        name_ranges: item.name_ranges,
6312                        body_range: item
6313                            .body_range
6314                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6315                        annotation_range: item
6316                            .annotation_range
6317                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6318                    })
6319                })
6320                .collect(),
6321        ))
6322    }
6323
6324    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6325        if id == ExcerptId::min() {
6326            Locator::min_ref()
6327        } else if id == ExcerptId::max() {
6328            Locator::max_ref()
6329        } else {
6330            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6331            if let Some(entry) = item
6332                && entry.id == id
6333            {
6334                return &entry.locator;
6335            }
6336            panic!("invalid excerpt id {id:?}")
6337        }
6338    }
6339
6340    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6341    fn excerpt_locators_for_ids(
6342        &self,
6343        ids: impl IntoIterator<Item = ExcerptId>,
6344    ) -> SmallVec<[Locator; 1]> {
6345        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6346        sorted_ids.sort_unstable();
6347        sorted_ids.dedup();
6348        let mut locators = SmallVec::new();
6349
6350        while sorted_ids.last() == Some(&ExcerptId::max()) {
6351            sorted_ids.pop();
6352            locators.push(Locator::max());
6353        }
6354
6355        let mut sorted_ids = sorted_ids.into_iter().peekable();
6356        locators.extend(
6357            sorted_ids
6358                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6359                .map(|_| Locator::min()),
6360        );
6361
6362        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6363        for id in sorted_ids {
6364            if cursor.seek_forward(&id, Bias::Left) {
6365                locators.push(cursor.item().unwrap().locator.clone());
6366            } else {
6367                panic!("invalid excerpt id {:?}", id);
6368            }
6369        }
6370
6371        locators.sort_unstable();
6372        locators
6373    }
6374
6375    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6376        Some(self.excerpt(excerpt_id)?.buffer_id)
6377    }
6378
6379    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6380        Some(&self.excerpt(excerpt_id)?.buffer)
6381    }
6382
6383    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6384        let mut cursor = self
6385            .excerpts
6386            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6387        let locator = self.excerpt_locator_for_id(excerpt_id);
6388        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6389        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6390            sought_exact = true;
6391            cursor.prev();
6392        } else if excerpt_id == ExcerptId::min() {
6393            sought_exact = true;
6394        }
6395        if sought_exact {
6396            let start = cursor.start().1;
6397            let end = cursor.end().1;
6398            let mut diff_transforms = self
6399                .diff_transforms
6400                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6401            diff_transforms.seek(&start, Bias::Left);
6402            let overshoot = start - diff_transforms.start().0;
6403            let start = diff_transforms.start().1 + overshoot;
6404            diff_transforms.seek(&end, Bias::Right);
6405            let overshoot = end - diff_transforms.start().0;
6406            let end = diff_transforms.start().1 + overshoot;
6407            Some(start.0..end.0)
6408        } else {
6409            None
6410        }
6411    }
6412
6413    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6414    /// to have the same excerpt id as the one passed in, with the exception of
6415    /// `ExcerptId::max()`.
6416    ///
6417    /// Callers of this function should generally use the resulting excerpt's `id` field
6418    /// afterwards.
6419    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6420        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6421        let locator = self.excerpt_locator_for_id(excerpt_id);
6422        cursor.seek(&Some(locator), Bias::Left);
6423        if let Some(excerpt) = cursor.item()
6424            && excerpt.id == excerpt_id
6425        {
6426            return Some(excerpt);
6427        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6428            cursor.prev();
6429            return cursor.item();
6430        }
6431        None
6432    }
6433
6434    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6435    pub fn excerpt_containing<T: ToOffset>(
6436        &self,
6437        range: Range<T>,
6438    ) -> Option<MultiBufferExcerpt<'_>> {
6439        let range = range.start.to_offset(self)..range.end.to_offset(self);
6440        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6441        cursor.seek(&range.start);
6442
6443        let start_excerpt = cursor.excerpt()?;
6444        if range.end != range.start {
6445            cursor.seek_forward(&range.end);
6446            if cursor.excerpt()?.id != start_excerpt.id {
6447                return None;
6448            }
6449        }
6450
6451        cursor.seek_to_start_of_current_excerpt();
6452        let region = cursor.region()?;
6453        let offset = region.range.start;
6454        let buffer_offset = start_excerpt.buffer_start_offset();
6455        let excerpt_offset = *cursor.excerpts.start();
6456        Some(MultiBufferExcerpt {
6457            diff_transforms: cursor.diff_transforms,
6458            excerpt: start_excerpt,
6459            offset,
6460            buffer_offset,
6461            excerpt_offset,
6462        })
6463    }
6464
6465    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6466        if let Some(id) = anchor.text_anchor.buffer_id {
6467            return Some(id);
6468        }
6469        let excerpt = self.excerpt_containing(anchor..anchor)?;
6470        Some(excerpt.buffer_id())
6471    }
6472
6473    pub fn selections_in_range<'a>(
6474        &'a self,
6475        range: &'a Range<Anchor>,
6476        include_local: bool,
6477    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6478        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6479        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6480        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6481        cursor.seek(start_locator, Bias::Left);
6482        cursor
6483            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6484            .flat_map(move |excerpt| {
6485                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6486                if excerpt.id == range.start.excerpt_id {
6487                    query_range.start = range.start.text_anchor;
6488                }
6489                if excerpt.id == range.end.excerpt_id {
6490                    query_range.end = range.end.text_anchor;
6491                }
6492
6493                excerpt
6494                    .buffer
6495                    .selections_in_range(query_range, include_local)
6496                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6497                        selections.map(move |selection| {
6498                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6499                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6500                            if range.start.cmp(&start, self).is_gt() {
6501                                start = range.start;
6502                            }
6503                            if range.end.cmp(&end, self).is_lt() {
6504                                end = range.end;
6505                            }
6506
6507                            (
6508                                replica_id,
6509                                line_mode,
6510                                cursor_shape,
6511                                Selection {
6512                                    id: selection.id,
6513                                    start,
6514                                    end,
6515                                    reversed: selection.reversed,
6516                                    goal: selection.goal,
6517                                },
6518                            )
6519                        })
6520                    })
6521            })
6522    }
6523
6524    pub fn show_headers(&self) -> bool {
6525        self.show_headers
6526    }
6527
6528    /// Visually annotates a position or range with the `Debug` representation of a value. The
6529    /// callsite of this function is used as a key - previous annotations will be removed.
6530    #[cfg(debug_assertions)]
6531    #[track_caller]
6532    pub fn debug<V, R>(&self, ranges: &R, value: V)
6533    where
6534        R: debug::ToMultiBufferDebugRanges,
6535        V: std::fmt::Debug,
6536    {
6537        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6538    }
6539
6540    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6541    /// debug annotations with the same key will be removed. The key is also used to determine the
6542    /// annotation's color.
6543    #[cfg(debug_assertions)]
6544    #[track_caller]
6545    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6546    where
6547        K: std::hash::Hash + 'static,
6548        R: debug::ToMultiBufferDebugRanges,
6549        V: std::fmt::Debug,
6550    {
6551        let text_ranges = ranges
6552            .to_multi_buffer_debug_ranges(self)
6553            .into_iter()
6554            .flat_map(|range| {
6555                self.range_to_buffer_ranges(range).into_iter().map(
6556                    |(buffer, range, _excerpt_id)| {
6557                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6558                    },
6559                )
6560            })
6561            .collect();
6562        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6563            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6564        });
6565    }
6566
6567    fn excerpt_edits_for_diff_change(
6568        &self,
6569        buffer_state: &BufferState,
6570        diff_change_range: Range<usize>,
6571    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6572        let mut excerpt_edits = Vec::new();
6573        for locator in &buffer_state.excerpts {
6574            let mut cursor = self
6575                .excerpts
6576                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6577            cursor.seek_forward(&Some(locator), Bias::Left);
6578            if let Some(excerpt) = cursor.item()
6579                && excerpt.locator == *locator
6580            {
6581                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6582                if diff_change_range.end < excerpt_buffer_range.start
6583                    || diff_change_range.start > excerpt_buffer_range.end
6584                {
6585                    continue;
6586                }
6587                let excerpt_start = cursor.start().1;
6588                let excerpt_len = excerpt.text_summary.len;
6589                let diff_change_start_in_excerpt = diff_change_range
6590                    .start
6591                    .saturating_sub(excerpt_buffer_range.start);
6592                let diff_change_end_in_excerpt = diff_change_range
6593                    .end
6594                    .saturating_sub(excerpt_buffer_range.start);
6595                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6596                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6597                excerpt_edits.push(Edit {
6598                    old: edit_start..edit_end,
6599                    new: edit_start..edit_end,
6600                });
6601            }
6602        }
6603        excerpt_edits
6604    }
6605}
6606
6607#[cfg(any(test, feature = "test-support"))]
6608impl MultiBufferSnapshot {
6609    pub fn random_byte_range(
6610        &self,
6611        start_offset: MultiBufferOffset,
6612        rng: &mut impl rand::Rng,
6613    ) -> Range<MultiBufferOffset> {
6614        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6615        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6616        start..end
6617    }
6618
6619    #[cfg(any(test, feature = "test-support"))]
6620    fn check_invariants(&self) {
6621        let excerpts = self.excerpts.items(());
6622        let excerpt_ids = self.excerpt_ids.items(());
6623
6624        for (ix, excerpt) in excerpts.iter().enumerate() {
6625            if ix == 0 {
6626                if excerpt.locator <= Locator::min() {
6627                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6628                }
6629            } else if excerpt.locator <= excerpts[ix - 1].locator {
6630                panic!("excerpts are out-of-order: {:?}", excerpts);
6631            }
6632        }
6633
6634        for (ix, entry) in excerpt_ids.iter().enumerate() {
6635            if ix == 0 {
6636                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6637                    panic!("invalid first excerpt id {:?}", entry.id);
6638                }
6639            } else if entry.id <= excerpt_ids[ix - 1].id {
6640                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6641            }
6642        }
6643
6644        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6645            panic!(
6646                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6647                self.excerpts.summary().text,
6648                self.diff_transforms.summary().input,
6649                self.diff_transforms.items(()),
6650            );
6651        }
6652
6653        let mut prev_transform: Option<&DiffTransform> = None;
6654        for item in self.diff_transforms.iter() {
6655            if let DiffTransform::BufferContent {
6656                summary,
6657                inserted_hunk_info,
6658            } = item
6659            {
6660                if let Some(DiffTransform::BufferContent {
6661                    inserted_hunk_info: prev_inserted_hunk_info,
6662                    ..
6663                }) = prev_transform
6664                    && *inserted_hunk_info == *prev_inserted_hunk_info
6665                {
6666                    panic!(
6667                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6668                        self.diff_transforms.items(())
6669                    );
6670                }
6671                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6672                    panic!("empty buffer content transform");
6673                }
6674            }
6675            prev_transform = Some(item);
6676        }
6677    }
6678}
6679
6680impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6681where
6682    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6683    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6684{
6685    fn seek(&mut self, position: &MBD) {
6686        let position = OutputDimension(*position);
6687        self.cached_region.take();
6688        self.diff_transforms.seek(&position, Bias::Right);
6689        if self.diff_transforms.item().is_none()
6690            && self.diff_transforms.start().output_dimension == position
6691        {
6692            self.diff_transforms.prev();
6693        }
6694
6695        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6696        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6697            let overshoot = position - self.diff_transforms.start().output_dimension;
6698            excerpt_position += overshoot;
6699        }
6700
6701        self.excerpts.seek(&excerpt_position, Bias::Right);
6702        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6703            self.excerpts.prev();
6704        }
6705    }
6706
6707    fn seek_forward(&mut self, position: &MBD) {
6708        let position = OutputDimension(*position);
6709        self.cached_region.take();
6710        self.diff_transforms.seek_forward(&position, Bias::Right);
6711        if self.diff_transforms.item().is_none()
6712            && self.diff_transforms.start().output_dimension == position
6713        {
6714            self.diff_transforms.prev();
6715        }
6716
6717        let overshoot = position - self.diff_transforms.start().output_dimension;
6718        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6719        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6720            excerpt_position += overshoot;
6721        }
6722
6723        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6724        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6725            self.excerpts.prev();
6726        }
6727    }
6728
6729    fn next_excerpt(&mut self) {
6730        self.excerpts.next();
6731        self.seek_to_start_of_current_excerpt();
6732    }
6733
6734    fn prev_excerpt(&mut self) {
6735        self.excerpts.prev();
6736        self.seek_to_start_of_current_excerpt();
6737    }
6738
6739    fn seek_to_start_of_current_excerpt(&mut self) {
6740        self.cached_region.take();
6741        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6742        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6743            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6744            && self.diff_transforms.next_item().is_some()
6745        {
6746            self.diff_transforms.next();
6747        }
6748    }
6749
6750    fn next(&mut self) {
6751        self.cached_region.take();
6752        match self
6753            .diff_transforms
6754            .end()
6755            .excerpt_dimension
6756            .cmp(&self.excerpts.end())
6757        {
6758            cmp::Ordering::Less => self.diff_transforms.next(),
6759            cmp::Ordering::Greater => self.excerpts.next(),
6760            cmp::Ordering::Equal => {
6761                self.diff_transforms.next();
6762                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6763                    || self.diff_transforms.item().is_none()
6764                {
6765                    self.excerpts.next();
6766                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6767                    self.diff_transforms.item()
6768                    && self
6769                        .excerpts
6770                        .item()
6771                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6772                {
6773                    self.excerpts.next();
6774                }
6775            }
6776        }
6777    }
6778
6779    fn prev(&mut self) {
6780        self.cached_region.take();
6781        match self
6782            .diff_transforms
6783            .start()
6784            .excerpt_dimension
6785            .cmp(self.excerpts.start())
6786        {
6787            cmp::Ordering::Less => self.excerpts.prev(),
6788            cmp::Ordering::Greater => self.diff_transforms.prev(),
6789            cmp::Ordering::Equal => {
6790                self.diff_transforms.prev();
6791                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6792                    || self.diff_transforms.item().is_none()
6793                {
6794                    self.excerpts.prev();
6795                }
6796            }
6797        }
6798    }
6799
6800    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6801        if self.cached_region.is_none() {
6802            self.cached_region = self.build_region();
6803        }
6804        self.cached_region.clone()
6805    }
6806
6807    fn is_at_start_of_excerpt(&mut self) -> bool {
6808        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6809            return false;
6810        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6811            return true;
6812        }
6813
6814        self.diff_transforms.prev();
6815        let prev_transform = self.diff_transforms.item();
6816        self.diff_transforms.next();
6817
6818        prev_transform.is_none_or(|next_transform| {
6819            matches!(next_transform, DiffTransform::BufferContent { .. })
6820        })
6821    }
6822
6823    fn is_at_end_of_excerpt(&mut self) -> bool {
6824        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6825            return false;
6826        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6827            || self.diff_transforms.item().is_none()
6828        {
6829            return true;
6830        }
6831
6832        let next_transform = self.diff_transforms.next_item();
6833        next_transform.is_none_or(|next_transform| match next_transform {
6834            DiffTransform::BufferContent { .. } => true,
6835            DiffTransform::DeletedHunk { hunk_info, .. } => self
6836                .excerpts
6837                .item()
6838                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6839        })
6840    }
6841
6842    fn main_buffer_position(&self) -> Option<BD> {
6843        let excerpt = self.excerpts.item()?;
6844        let buffer = &excerpt.buffer;
6845        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6846        let mut buffer_start = buffer_context_start;
6847        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6848        buffer_start += overshoot;
6849        Some(buffer_start)
6850    }
6851
6852    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6853        let excerpt = self.excerpts.item()?;
6854        match self.diff_transforms.item()? {
6855            DiffTransform::DeletedHunk {
6856                buffer_id,
6857                base_text_byte_range,
6858                has_trailing_newline,
6859                hunk_info,
6860                ..
6861            } => {
6862                let diff = self.diffs.get(buffer_id)?;
6863                let buffer = diff.base_text();
6864                let mut rope_cursor = buffer.as_rope().cursor(0);
6865                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6866                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6867                let mut buffer_end = buffer_start;
6868                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6869                let start = self.diff_transforms.start().output_dimension.0;
6870                let end = self.diff_transforms.end().output_dimension.0;
6871                Some(MultiBufferRegion {
6872                    buffer,
6873                    excerpt,
6874                    has_trailing_newline: *has_trailing_newline,
6875                    is_main_buffer: false,
6876                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6877                        hunk_info.hunk_secondary_status,
6878                    )),
6879                    buffer_range: buffer_start..buffer_end,
6880                    range: start..end,
6881                })
6882            }
6883            DiffTransform::BufferContent {
6884                inserted_hunk_info, ..
6885            } => {
6886                let buffer = &excerpt.buffer;
6887                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6888
6889                let mut start = self.diff_transforms.start().output_dimension.0;
6890                let mut buffer_start = buffer_context_start;
6891                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6892                    let overshoot =
6893                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6894                    start += overshoot;
6895                } else {
6896                    let overshoot =
6897                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6898                    buffer_start += overshoot;
6899                }
6900
6901                let mut end;
6902                let mut buffer_end;
6903                let has_trailing_newline;
6904                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6905                    let overshoot =
6906                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6907                    end = self.diff_transforms.end().output_dimension.0;
6908                    buffer_end = buffer_context_start;
6909                    buffer_end += overshoot;
6910                    has_trailing_newline = false;
6911                } else {
6912                    let overshoot =
6913                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6914                    end = self.diff_transforms.start().output_dimension.0;
6915                    end += overshoot;
6916                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6917                    has_trailing_newline = excerpt.has_trailing_newline;
6918                };
6919
6920                let diff_hunk_status = inserted_hunk_info.map(|info| {
6921                    if info.is_logically_deleted {
6922                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6923                    } else {
6924                        DiffHunkStatus::added(info.hunk_secondary_status)
6925                    }
6926                });
6927
6928                Some(MultiBufferRegion {
6929                    buffer,
6930                    excerpt,
6931                    has_trailing_newline,
6932                    is_main_buffer: true,
6933                    diff_hunk_status,
6934                    buffer_range: buffer_start..buffer_end,
6935                    range: start..end,
6936                })
6937            }
6938        }
6939    }
6940
6941    fn excerpt(&self) -> Option<&'a Excerpt> {
6942        self.excerpts.item()
6943    }
6944}
6945
6946impl Excerpt {
6947    fn new(
6948        id: ExcerptId,
6949        locator: Locator,
6950        buffer_id: BufferId,
6951        buffer: BufferSnapshot,
6952        range: ExcerptRange<text::Anchor>,
6953        has_trailing_newline: bool,
6954    ) -> Self {
6955        Excerpt {
6956            id,
6957            locator,
6958            max_buffer_row: range.context.end.to_point(&buffer).row,
6959            text_summary: buffer
6960                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6961            buffer_id,
6962            buffer,
6963            range,
6964            has_trailing_newline,
6965        }
6966    }
6967
6968    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6969        let content_start = self.range.context.start.to_offset(&self.buffer);
6970        let chunks_start = content_start + range.start;
6971        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6972
6973        let has_footer = self.has_trailing_newline
6974            && range.start <= self.text_summary.len
6975            && range.end > self.text_summary.len;
6976
6977        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6978
6979        ExcerptChunks {
6980            excerpt_id: self.id,
6981            content_chunks,
6982            has_footer,
6983        }
6984    }
6985
6986    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6987        let content_start = self.range.context.start.to_offset(&self.buffer);
6988        let chunks_start = content_start + range.start;
6989        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6990        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6991        excerpt_chunks.has_footer = self.has_trailing_newline
6992            && range.start <= self.text_summary.len
6993            && range.end > self.text_summary.len;
6994    }
6995
6996    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6997        if text_anchor
6998            .cmp(&self.range.context.start, &self.buffer)
6999            .is_lt()
7000        {
7001            self.range.context.start
7002        } else if text_anchor
7003            .cmp(&self.range.context.end, &self.buffer)
7004            .is_gt()
7005        {
7006            self.range.context.end
7007        } else {
7008            text_anchor
7009        }
7010    }
7011
7012    fn contains(&self, anchor: &Anchor) -> bool {
7013        (anchor.text_anchor.buffer_id == None
7014            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7015            && self
7016                .range
7017                .context
7018                .start
7019                .cmp(&anchor.text_anchor, &self.buffer)
7020                .is_le()
7021            && self
7022                .range
7023                .context
7024                .end
7025                .cmp(&anchor.text_anchor, &self.buffer)
7026                .is_ge()
7027    }
7028
7029    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7030    fn buffer_start_offset(&self) -> BufferOffset {
7031        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7032    }
7033
7034    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7035    fn buffer_end_offset(&self) -> BufferOffset {
7036        self.buffer_start_offset() + self.text_summary.len
7037    }
7038}
7039
7040impl<'a> MultiBufferExcerpt<'a> {
7041    pub fn id(&self) -> ExcerptId {
7042        self.excerpt.id
7043    }
7044
7045    pub fn buffer_id(&self) -> BufferId {
7046        self.excerpt.buffer_id
7047    }
7048
7049    pub fn start_anchor(&self) -> Anchor {
7050        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7051    }
7052
7053    pub fn end_anchor(&self) -> Anchor {
7054        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7055    }
7056
7057    pub fn buffer(&self) -> &'a BufferSnapshot {
7058        &self.excerpt.buffer
7059    }
7060
7061    pub fn buffer_range(&self) -> Range<BufferOffset> {
7062        self.buffer_offset
7063            ..BufferOffset(
7064                self.excerpt
7065                    .range
7066                    .context
7067                    .end
7068                    .to_offset(&self.excerpt.buffer.text),
7069            )
7070    }
7071
7072    pub fn start_offset(&self) -> MultiBufferOffset {
7073        self.offset
7074    }
7075
7076    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7077    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7078        self.map_range_to_buffer(offset..offset).start
7079    }
7080
7081    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7082    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7083        self.diff_transforms
7084            .seek(&OutputDimension(range.start), Bias::Right);
7085        let start = self.map_offset_to_buffer_internal(range.start);
7086        let end = if range.end > range.start {
7087            self.diff_transforms
7088                .seek_forward(&OutputDimension(range.end), Bias::Right);
7089            self.map_offset_to_buffer_internal(range.end)
7090        } else {
7091            start
7092        };
7093        start..end
7094    }
7095
7096    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7097        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7098        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7099            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7100        };
7101        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7102        self.buffer_offset + offset_in_excerpt
7103    }
7104
7105    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7106    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7107        self.map_range_from_buffer(buffer_offset..buffer_offset)
7108            .start
7109    }
7110
7111    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7112    pub fn map_range_from_buffer(
7113        &mut self,
7114        buffer_range: Range<BufferOffset>,
7115    ) -> Range<MultiBufferOffset> {
7116        if buffer_range.start < self.buffer_offset {
7117            log::warn!(
7118                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7119            );
7120            return self.offset..self.offset;
7121        }
7122        let overshoot = buffer_range.start - self.buffer_offset;
7123        let excerpt_offset = self.excerpt_offset + overshoot;
7124        let excerpt_seek_dim = excerpt_offset;
7125        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7126        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7127            log::warn!(
7128                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7129            );
7130            return self.offset..self.offset;
7131        }
7132        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7133        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7134
7135        let end = if buffer_range.start < buffer_range.end {
7136            let overshoot = buffer_range.end - self.buffer_offset;
7137            let excerpt_offset = self.excerpt_offset + overshoot;
7138            let excerpt_seek_dim = excerpt_offset;
7139            self.diff_transforms
7140                .seek_forward(&excerpt_seek_dim, Bias::Right);
7141            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7142            // todo(lw): Clamp end to the excerpt boundaries
7143            self.diff_transforms.start().output_dimension.0 + overshoot
7144        } else {
7145            start
7146        };
7147
7148        start..end
7149    }
7150
7151    /// Returns true if the entirety of the given range is in the buffer's excerpt
7152    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7153        range.start >= self.excerpt.buffer_start_offset()
7154            && range.end <= self.excerpt.buffer_end_offset()
7155    }
7156
7157    pub fn max_buffer_row(&self) -> u32 {
7158        self.excerpt.max_buffer_row
7159    }
7160}
7161
7162impl ExcerptId {
7163    pub fn min() -> Self {
7164        Self(0)
7165    }
7166
7167    pub fn max() -> Self {
7168        Self(u32::MAX)
7169    }
7170
7171    pub fn to_proto(self) -> u64 {
7172        self.0 as _
7173    }
7174
7175    pub fn from_proto(proto: u64) -> Self {
7176        Self(proto as _)
7177    }
7178
7179    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7180        let a = snapshot.excerpt_locator_for_id(*self);
7181        let b = snapshot.excerpt_locator_for_id(*other);
7182        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7183    }
7184}
7185
7186impl From<ExcerptId> for usize {
7187    fn from(val: ExcerptId) -> Self {
7188        val.0 as usize
7189    }
7190}
7191
7192impl fmt::Debug for Excerpt {
7193    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7194        f.debug_struct("Excerpt")
7195            .field("id", &self.id)
7196            .field("locator", &self.locator)
7197            .field("buffer_id", &self.buffer_id)
7198            .field("range", &self.range)
7199            .field("text_summary", &self.text_summary)
7200            .field("has_trailing_newline", &self.has_trailing_newline)
7201            .finish()
7202    }
7203}
7204
7205impl sum_tree::Item for Excerpt {
7206    type Summary = ExcerptSummary;
7207
7208    fn summary(&self, _cx: ()) -> Self::Summary {
7209        let mut text = self.text_summary;
7210        if self.has_trailing_newline {
7211            text += TextSummary::from("\n");
7212        }
7213        ExcerptSummary {
7214            excerpt_id: self.id,
7215            excerpt_locator: self.locator.clone(),
7216            widest_line_number: self.max_buffer_row,
7217            text: text.into(),
7218        }
7219    }
7220}
7221
7222impl sum_tree::Item for ExcerptIdMapping {
7223    type Summary = ExcerptId;
7224
7225    fn summary(&self, _cx: ()) -> Self::Summary {
7226        self.id
7227    }
7228}
7229
7230impl sum_tree::KeyedItem for ExcerptIdMapping {
7231    type Key = ExcerptId;
7232
7233    fn key(&self) -> Self::Key {
7234        self.id
7235    }
7236}
7237
7238impl DiffTransform {
7239    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7240        match self {
7241            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7242            DiffTransform::BufferContent {
7243                inserted_hunk_info, ..
7244            } => *inserted_hunk_info,
7245        }
7246    }
7247}
7248
7249impl sum_tree::Item for DiffTransform {
7250    type Summary = DiffTransformSummary;
7251
7252    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7253        match self {
7254            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7255                input: *summary,
7256                output: *summary,
7257            },
7258            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7259                input: MBTextSummary::default(),
7260                output: summary.into(),
7261            },
7262        }
7263    }
7264}
7265
7266impl DiffTransformSummary {
7267    fn excerpt_len(&self) -> ExcerptOffset {
7268        ExcerptDimension(self.input.len)
7269    }
7270}
7271
7272impl sum_tree::ContextLessSummary for DiffTransformSummary {
7273    fn zero() -> Self {
7274        DiffTransformSummary {
7275            input: MBTextSummary::default(),
7276            output: MBTextSummary::default(),
7277        }
7278    }
7279
7280    fn add_summary(&mut self, other: &Self) {
7281        self.input += other.input;
7282        self.output += other.output;
7283    }
7284}
7285
7286impl sum_tree::ContextLessSummary for ExcerptId {
7287    fn zero() -> Self {
7288        Self(0)
7289    }
7290
7291    fn add_summary(&mut self, summary: &Self) {
7292        *self = cmp::max(*self, *summary);
7293    }
7294}
7295
7296impl sum_tree::ContextLessSummary for ExcerptSummary {
7297    fn zero() -> Self {
7298        Self::default()
7299    }
7300
7301    fn add_summary(&mut self, summary: &Self) {
7302        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7303        self.excerpt_locator = summary.excerpt_locator.clone();
7304        self.text += summary.text;
7305        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7306    }
7307}
7308
7309impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7310    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7311        Ord::cmp(&Some(self), cursor_location)
7312    }
7313}
7314
7315impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7316    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7317        Ord::cmp(self, &cursor_location.excerpt_locator)
7318    }
7319}
7320
7321impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7322where
7323    MBD: MultiBufferDimension + Default,
7324{
7325    fn zero(_: ()) -> Self {
7326        ExcerptDimension(MBD::default())
7327    }
7328
7329    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7330        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7331    }
7332}
7333
7334impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7335    fn zero(_cx: ()) -> Self {
7336        Default::default()
7337    }
7338
7339    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7340        *self = Some(&summary.excerpt_locator);
7341    }
7342}
7343
7344impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7345    fn zero(_cx: ()) -> Self {
7346        Default::default()
7347    }
7348
7349    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7350        *self = Some(summary.excerpt_id);
7351    }
7352}
7353
7354#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7355struct OutputDimension<T>(T);
7356
7357impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7358    fn eq(&self, other: &T) -> bool {
7359        self.0 == *other
7360    }
7361}
7362
7363impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7364    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7365        self.0.partial_cmp(other)
7366    }
7367}
7368
7369impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7370where
7371    T: ops::Sub<U, Output = R>,
7372{
7373    type Output = R;
7374
7375    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7376        self.0 - other.0
7377    }
7378}
7379
7380impl<R, T, U> ops::Add<U> for OutputDimension<T>
7381where
7382    T: ops::Add<U, Output = R>,
7383{
7384    type Output = OutputDimension<R>;
7385
7386    fn add(self, other: U) -> Self::Output {
7387        OutputDimension(self.0 + other)
7388    }
7389}
7390
7391impl<T, U> AddAssign<U> for OutputDimension<T>
7392where
7393    T: AddAssign<U>,
7394{
7395    fn add_assign(&mut self, other: U) {
7396        self.0 += other;
7397    }
7398}
7399
7400impl<T, U> SubAssign<U> for OutputDimension<T>
7401where
7402    T: SubAssign<U>,
7403{
7404    fn sub_assign(&mut self, other: U) {
7405        self.0 -= other;
7406    }
7407}
7408
7409#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7410struct ExcerptDimension<T>(T);
7411
7412impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7413    fn eq(&self, other: &T) -> bool {
7414        self.0 == *other
7415    }
7416}
7417
7418impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7419    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7420        self.0.partial_cmp(other)
7421    }
7422}
7423
7424impl ExcerptOffset {
7425    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7426        self.0.saturating_sub(other.0)
7427    }
7428}
7429
7430impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7431where
7432    T: ops::Sub<U, Output = R>,
7433{
7434    type Output = R;
7435
7436    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7437        self.0 - other.0
7438    }
7439}
7440
7441impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7442where
7443    T: ops::Add<U, Output = R>,
7444{
7445    type Output = ExcerptDimension<R>;
7446
7447    fn add(self, other: U) -> Self::Output {
7448        ExcerptDimension(self.0 + other)
7449    }
7450}
7451
7452impl<T, U> AddAssign<U> for ExcerptDimension<T>
7453where
7454    T: AddAssign<U>,
7455{
7456    fn add_assign(&mut self, other: U) {
7457        self.0 += other;
7458    }
7459}
7460
7461impl<T, U> SubAssign<U> for ExcerptDimension<T>
7462where
7463    T: SubAssign<U>,
7464{
7465    fn sub_assign(&mut self, other: U) {
7466        self.0 -= other;
7467    }
7468}
7469
7470impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7471    fn zero(_: ()) -> Self {
7472        MultiBufferOffset::ZERO
7473    }
7474
7475    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7476        *self += summary.output.len;
7477    }
7478}
7479
7480impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7481    for ExcerptDimension<MBD>
7482where
7483    MBD: MultiBufferDimension + Ord,
7484{
7485    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7486        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7487    }
7488}
7489
7490impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7491    for ExcerptDimension<MBD>
7492where
7493    MBD: MultiBufferDimension + Ord,
7494{
7495    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7496        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7497    }
7498}
7499
7500impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7501    for ExcerptDimension<MBD>
7502{
7503    fn zero(_: ()) -> Self {
7504        ExcerptDimension(MBD::default())
7505    }
7506
7507    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7508        self.0.add_mb_text_summary(&summary.input)
7509    }
7510}
7511
7512impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7513    for OutputDimension<MBD>
7514where
7515    MBD: MultiBufferDimension + Ord,
7516{
7517    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7518        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7519    }
7520}
7521
7522impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7523    for OutputDimension<MBD>
7524{
7525    fn zero(_: ()) -> Self {
7526        OutputDimension(MBD::default())
7527    }
7528
7529    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7530        self.0.add_mb_text_summary(&summary.output)
7531    }
7532}
7533
7534impl MultiBufferRows<'_> {
7535    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7536        self.point = Point::new(row, 0);
7537        self.cursor.seek(&self.point);
7538    }
7539}
7540
7541impl Iterator for MultiBufferRows<'_> {
7542    type Item = RowInfo;
7543
7544    fn next(&mut self) -> Option<Self::Item> {
7545        if self.is_empty && self.point.row == 0 {
7546            self.point += Point::new(1, 0);
7547            return Some(RowInfo {
7548                buffer_id: None,
7549                buffer_row: Some(0),
7550                multibuffer_row: Some(MultiBufferRow(0)),
7551                diff_status: None,
7552                expand_info: None,
7553                wrapped_buffer_row: None,
7554            });
7555        }
7556
7557        let mut region = self.cursor.region()?;
7558        while self.point >= region.range.end {
7559            self.cursor.next();
7560            if let Some(next_region) = self.cursor.region() {
7561                region = next_region;
7562            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7563                let multibuffer_row = MultiBufferRow(self.point.row);
7564                let last_excerpt = self
7565                    .cursor
7566                    .excerpts
7567                    .item()
7568                    .or(self.cursor.excerpts.prev_item())?;
7569                let last_row = last_excerpt
7570                    .range
7571                    .context
7572                    .end
7573                    .to_point(&last_excerpt.buffer)
7574                    .row;
7575
7576                let first_row = last_excerpt
7577                    .range
7578                    .context
7579                    .start
7580                    .to_point(&last_excerpt.buffer)
7581                    .row;
7582
7583                let expand_info = if self.is_singleton {
7584                    None
7585                } else {
7586                    let needs_expand_up = first_row == last_row
7587                        && last_row > 0
7588                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7589                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7590
7591                    if needs_expand_up && needs_expand_down {
7592                        Some(ExpandExcerptDirection::UpAndDown)
7593                    } else if needs_expand_up {
7594                        Some(ExpandExcerptDirection::Up)
7595                    } else if needs_expand_down {
7596                        Some(ExpandExcerptDirection::Down)
7597                    } else {
7598                        None
7599                    }
7600                    .map(|direction| ExpandInfo {
7601                        direction,
7602                        excerpt_id: last_excerpt.id,
7603                    })
7604                };
7605                self.point += Point::new(1, 0);
7606                return Some(RowInfo {
7607                    buffer_id: Some(last_excerpt.buffer_id),
7608                    buffer_row: Some(last_row),
7609                    multibuffer_row: Some(multibuffer_row),
7610                    diff_status: None,
7611                    wrapped_buffer_row: None,
7612                    expand_info,
7613                });
7614            } else {
7615                return None;
7616            };
7617        }
7618
7619        let overshoot = self.point - region.range.start;
7620        let buffer_point = region.buffer_range.start + overshoot;
7621        let expand_info = if self.is_singleton {
7622            None
7623        } else {
7624            let needs_expand_up = self.point.row == region.range.start.row
7625                && self.cursor.is_at_start_of_excerpt()
7626                && buffer_point.row > 0;
7627            let needs_expand_down = (region.excerpt.has_trailing_newline
7628                && self.point.row + 1 == region.range.end.row
7629                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7630                && self.cursor.is_at_end_of_excerpt()
7631                && buffer_point.row < region.buffer.max_point().row;
7632
7633            if needs_expand_up && needs_expand_down {
7634                Some(ExpandExcerptDirection::UpAndDown)
7635            } else if needs_expand_up {
7636                Some(ExpandExcerptDirection::Up)
7637            } else if needs_expand_down {
7638                Some(ExpandExcerptDirection::Down)
7639            } else {
7640                None
7641            }
7642            .map(|direction| ExpandInfo {
7643                direction,
7644                excerpt_id: region.excerpt.id,
7645            })
7646        };
7647
7648        let result = Some(RowInfo {
7649            buffer_id: Some(region.buffer.remote_id()),
7650            buffer_row: Some(buffer_point.row),
7651            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7652            diff_status: region
7653                .diff_hunk_status
7654                .filter(|_| self.point < region.range.end),
7655            expand_info,
7656            wrapped_buffer_row: None,
7657        });
7658        self.point += Point::new(1, 0);
7659        result
7660    }
7661}
7662
7663impl<'a> MultiBufferChunks<'a> {
7664    pub fn offset(&self) -> MultiBufferOffset {
7665        self.range.start
7666    }
7667
7668    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7669        self.diff_transforms.seek(&range.end, Bias::Right);
7670        let mut excerpt_end = self.diff_transforms.start().1;
7671        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7672            let overshoot = range.end - self.diff_transforms.start().0;
7673            excerpt_end += overshoot;
7674        }
7675
7676        self.diff_transforms.seek(&range.start, Bias::Right);
7677        let mut excerpt_start = self.diff_transforms.start().1;
7678        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7679            let overshoot = range.start - self.diff_transforms.start().0;
7680            excerpt_start += overshoot;
7681        }
7682
7683        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7684        self.buffer_chunk.take();
7685        self.range = range;
7686    }
7687
7688    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7689        self.excerpt_offset_range = new_range.clone();
7690        self.excerpts.seek(&new_range.start, Bias::Right);
7691        if let Some(excerpt) = self.excerpts.item() {
7692            let excerpt_start = *self.excerpts.start();
7693            if let Some(excerpt_chunks) = self
7694                .excerpt_chunks
7695                .as_mut()
7696                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7697            {
7698                excerpt.seek_chunks(
7699                    excerpt_chunks,
7700                    (self.excerpt_offset_range.start - excerpt_start)
7701                        ..(self.excerpt_offset_range.end - excerpt_start),
7702                );
7703            } else {
7704                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7705                    (self.excerpt_offset_range.start - excerpt_start)
7706                        ..(self.excerpt_offset_range.end - excerpt_start),
7707                    self.language_aware,
7708                ));
7709            }
7710        } else {
7711            self.excerpt_chunks = None;
7712        }
7713    }
7714
7715    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7716        loop {
7717            if self.excerpt_offset_range.is_empty() {
7718                return None;
7719            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7720                self.excerpt_offset_range.start += chunk.text.len();
7721                return Some(chunk);
7722            } else {
7723                self.excerpts.next();
7724                let excerpt = self.excerpts.item()?;
7725                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7726                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7727                    self.language_aware,
7728                ));
7729            }
7730        }
7731    }
7732}
7733
7734impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7735    type Item = &'a str;
7736
7737    fn next(&mut self) -> Option<Self::Item> {
7738        let mut region = self.cursor.region()?;
7739        if self.offset == region.range.start {
7740            self.cursor.prev();
7741            region = self.cursor.region()?;
7742            let start_overshoot = self.start.saturating_sub(region.range.start);
7743            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7744                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7745            ));
7746        }
7747
7748        if self.offset == region.range.end && region.has_trailing_newline {
7749            self.offset -= 1;
7750            Some("\n")
7751        } else {
7752            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7753            self.offset -= chunk.len();
7754            Some(chunk)
7755        }
7756    }
7757}
7758
7759impl<'a> Iterator for MultiBufferChunks<'a> {
7760    type Item = Chunk<'a>;
7761
7762    fn next(&mut self) -> Option<Chunk<'a>> {
7763        if self.range.start >= self.range.end {
7764            return None;
7765        }
7766        if self.range.start == self.diff_transforms.end().0 {
7767            self.diff_transforms.next();
7768        }
7769
7770        let diff_transform_start = self.diff_transforms.start().0;
7771        let diff_transform_end = self.diff_transforms.end().0;
7772        debug_assert!(
7773            self.range.start < diff_transform_end,
7774            "{:?} < {:?} of ({1:?}..{2:?})",
7775            self.range.start,
7776            diff_transform_end,
7777            diff_transform_start
7778        );
7779
7780        let diff_transform = self.diff_transforms.item()?;
7781        match diff_transform {
7782            DiffTransform::BufferContent { .. } => {
7783                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7784                    chunk
7785                } else {
7786                    let chunk = self.next_excerpt_chunk().unwrap();
7787                    self.buffer_chunk.insert(chunk)
7788                };
7789
7790                let chunk_end = self.range.start + chunk.text.len();
7791                let diff_transform_end = diff_transform_end.min(self.range.end);
7792
7793                if diff_transform_end < chunk_end {
7794                    let split_idx = diff_transform_end - self.range.start;
7795                    let (before, after) = chunk.text.split_at(split_idx);
7796                    self.range.start = diff_transform_end;
7797                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7798                    let chars = chunk.chars & mask;
7799                    let tabs = chunk.tabs & mask;
7800
7801                    chunk.text = after;
7802                    chunk.chars = chunk.chars >> split_idx;
7803                    chunk.tabs = chunk.tabs >> split_idx;
7804
7805                    Some(Chunk {
7806                        text: before,
7807                        chars,
7808                        tabs,
7809                        ..chunk.clone()
7810                    })
7811                } else {
7812                    self.range.start = chunk_end;
7813                    self.buffer_chunk.take()
7814                }
7815            }
7816            DiffTransform::DeletedHunk {
7817                buffer_id,
7818                base_text_byte_range,
7819                has_trailing_newline,
7820                ..
7821            } => {
7822                let base_text_start =
7823                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7824                let base_text_end =
7825                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7826                let base_text_end = base_text_end.min(base_text_byte_range.end);
7827
7828                let mut chunks = if let Some((_, mut chunks)) = self
7829                    .diff_base_chunks
7830                    .take()
7831                    .filter(|(id, _)| id == buffer_id)
7832                {
7833                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7834                    {
7835                        chunks.seek(base_text_start..base_text_end);
7836                    }
7837                    chunks
7838                } else {
7839                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7840                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7841                };
7842
7843                let chunk = if let Some(chunk) = chunks.next() {
7844                    self.range.start += chunk.text.len();
7845                    self.diff_base_chunks = Some((*buffer_id, chunks));
7846                    chunk
7847                } else {
7848                    debug_assert!(has_trailing_newline);
7849                    self.range.start += "\n".len();
7850                    Chunk {
7851                        text: "\n",
7852                        chars: 1u128,
7853                        ..Default::default()
7854                    }
7855                };
7856                Some(chunk)
7857            }
7858        }
7859    }
7860}
7861
7862impl MultiBufferBytes<'_> {
7863    fn consume(&mut self, len: usize) {
7864        self.range.start += len;
7865        self.chunk = &self.chunk[len..];
7866
7867        if !self.range.is_empty() && self.chunk.is_empty() {
7868            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7869                self.chunk = chunk;
7870            } else if self.has_trailing_newline {
7871                self.has_trailing_newline = false;
7872                self.chunk = b"\n";
7873            } else {
7874                self.cursor.next();
7875                if let Some(region) = self.cursor.region() {
7876                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7877                        region.buffer_range.start
7878                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7879                                .min(region.buffer_range.end),
7880                    );
7881                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7882                    self.excerpt_bytes = Some(excerpt_bytes);
7883                    self.has_trailing_newline =
7884                        region.has_trailing_newline && self.range.end >= region.range.end;
7885                    if self.chunk.is_empty() && self.has_trailing_newline {
7886                        self.has_trailing_newline = false;
7887                        self.chunk = b"\n";
7888                    }
7889                }
7890            }
7891        }
7892    }
7893}
7894
7895impl<'a> Iterator for MultiBufferBytes<'a> {
7896    type Item = &'a [u8];
7897
7898    fn next(&mut self) -> Option<Self::Item> {
7899        let chunk = self.chunk;
7900        if chunk.is_empty() {
7901            None
7902        } else {
7903            self.consume(chunk.len());
7904            Some(chunk)
7905        }
7906    }
7907}
7908
7909impl io::Read for MultiBufferBytes<'_> {
7910    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7911        let len = cmp::min(buf.len(), self.chunk.len());
7912        buf[..len].copy_from_slice(&self.chunk[..len]);
7913        if len > 0 {
7914            self.consume(len);
7915        }
7916        Ok(len)
7917    }
7918}
7919
7920impl io::Read for ReversedMultiBufferBytes<'_> {
7921    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7922        let len = cmp::min(buf.len(), self.chunk.len());
7923        buf[..len].copy_from_slice(&self.chunk[..len]);
7924        buf[..len].reverse();
7925        if len > 0 {
7926            self.range.end -= len;
7927            self.chunk = &self.chunk[..self.chunk.len() - len];
7928            if !self.range.is_empty()
7929                && self.chunk.is_empty()
7930                && let Some(chunk) = self.chunks.next()
7931            {
7932                self.chunk = chunk.as_bytes();
7933            }
7934        }
7935        Ok(len)
7936    }
7937}
7938
7939impl<'a> Iterator for ExcerptChunks<'a> {
7940    type Item = Chunk<'a>;
7941
7942    fn next(&mut self) -> Option<Self::Item> {
7943        if let Some(chunk) = self.content_chunks.next() {
7944            return Some(chunk);
7945        }
7946
7947        if self.has_footer {
7948            let text = "\n";
7949            let chars = 0b1;
7950            self.has_footer = false;
7951            return Some(Chunk {
7952                text,
7953                chars,
7954                ..Default::default()
7955            });
7956        }
7957
7958        None
7959    }
7960}
7961
7962impl ToOffset for Point {
7963    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7964        snapshot.point_to_offset(*self)
7965    }
7966    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7967        snapshot.point_to_offset_utf16(*self)
7968    }
7969}
7970
7971impl ToOffset for MultiBufferOffset {
7972    #[track_caller]
7973    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7974        assert!(
7975            *self <= snapshot.len(),
7976            "offset {} is greater than the snapshot.len() {}",
7977            self.0,
7978            snapshot.len().0,
7979        );
7980        *self
7981    }
7982    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7983        snapshot.offset_to_offset_utf16(*self)
7984    }
7985}
7986
7987impl ToOffset for MultiBufferOffsetUtf16 {
7988    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7989        snapshot.offset_utf16_to_offset(*self)
7990    }
7991
7992    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7993        *self
7994    }
7995}
7996
7997impl ToOffset for PointUtf16 {
7998    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7999        snapshot.point_utf16_to_offset(*self)
8000    }
8001    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8002        snapshot.point_utf16_to_offset_utf16(*self)
8003    }
8004}
8005
8006impl ToPoint for MultiBufferOffset {
8007    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8008        snapshot.offset_to_point(*self)
8009    }
8010    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8011        snapshot.offset_to_point_utf16(*self)
8012    }
8013}
8014
8015impl ToPoint for Point {
8016    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8017        *self
8018    }
8019    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8020        snapshot.point_to_point_utf16(*self)
8021    }
8022}
8023
8024impl ToPoint for PointUtf16 {
8025    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8026        snapshot.point_utf16_to_point(*self)
8027    }
8028    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8029        *self
8030    }
8031}
8032
8033impl From<ExcerptId> for EntityId {
8034    fn from(id: ExcerptId) -> Self {
8035        EntityId::from(id.0 as u64)
8036    }
8037}
8038
8039#[cfg(debug_assertions)]
8040pub mod debug {
8041    use super::*;
8042
8043    pub trait ToMultiBufferDebugRanges {
8044        fn to_multi_buffer_debug_ranges(
8045            &self,
8046            snapshot: &MultiBufferSnapshot,
8047        ) -> Vec<Range<MultiBufferOffset>>;
8048    }
8049
8050    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8051        fn to_multi_buffer_debug_ranges(
8052            &self,
8053            snapshot: &MultiBufferSnapshot,
8054        ) -> Vec<Range<MultiBufferOffset>> {
8055            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8056        }
8057    }
8058
8059    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8060        fn to_multi_buffer_debug_ranges(
8061            &self,
8062            snapshot: &MultiBufferSnapshot,
8063        ) -> Vec<Range<MultiBufferOffset>> {
8064            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8065                .to_multi_buffer_debug_ranges(snapshot)
8066        }
8067    }
8068
8069    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8070        fn to_multi_buffer_debug_ranges(
8071            &self,
8072            snapshot: &MultiBufferSnapshot,
8073        ) -> Vec<Range<MultiBufferOffset>> {
8074            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8075        }
8076    }
8077
8078    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8079        fn to_multi_buffer_debug_ranges(
8080            &self,
8081            snapshot: &MultiBufferSnapshot,
8082        ) -> Vec<Range<MultiBufferOffset>> {
8083            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8084        }
8085    }
8086
8087    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8088        fn to_multi_buffer_debug_ranges(
8089            &self,
8090            snapshot: &MultiBufferSnapshot,
8091        ) -> Vec<Range<MultiBufferOffset>> {
8092            self.iter()
8093                .map(|item| {
8094                    let offset = item.to_offset(snapshot);
8095                    offset..offset
8096                })
8097                .collect()
8098        }
8099    }
8100
8101    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8102        fn to_multi_buffer_debug_ranges(
8103            &self,
8104            snapshot: &MultiBufferSnapshot,
8105        ) -> Vec<Range<MultiBufferOffset>> {
8106            self.iter()
8107                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8108                .collect()
8109        }
8110    }
8111}