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