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, DiffChanged, DiffHunk,
  14    DiffHunkSecondaryStatus, DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    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, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  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;
  58use ztracing::instrument;
  59
  60pub use self::path_key::PathKey;
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    excerpts: Vec<Locator>,
 519    _subscriptions: [gpui::Subscription; 2],
 520}
 521
 522struct DiffState {
 523    diff: Entity<BufferDiff>,
 524    is_inverted: bool,
 525    _subscription: gpui::Subscription,
 526}
 527
 528impl DiffState {
 529    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 530        DiffStateSnapshot {
 531            diff: self.diff.read(cx).snapshot(cx),
 532            is_inverted: self.is_inverted,
 533        }
 534    }
 535}
 536
 537#[derive(Clone)]
 538struct DiffStateSnapshot {
 539    diff: BufferDiffSnapshot,
 540    is_inverted: bool,
 541}
 542
 543impl std::ops::Deref for DiffStateSnapshot {
 544    type Target = BufferDiffSnapshot;
 545
 546    fn deref(&self) -> &Self::Target {
 547        &self.diff
 548    }
 549}
 550
 551impl DiffState {
 552    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 553        DiffState {
 554            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 555                BufferDiffEvent::DiffChanged(DiffChanged {
 556                    changed_range,
 557                    base_text_changed_range: _,
 558                    extended_range,
 559                }) => {
 560                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 561                    let range = if use_extended {
 562                        extended_range.clone()
 563                    } else {
 564                        changed_range.clone()
 565                    };
 566                    if let Some(range) = range {
 567                        this.buffer_diff_changed(diff, range, cx)
 568                    }
 569                    cx.emit(Event::BufferDiffChanged);
 570                }
 571                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 572                _ => {}
 573            }),
 574            diff,
 575            is_inverted: false,
 576        }
 577    }
 578
 579    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 580        DiffState {
 581            _subscription: cx.subscribe(&diff, {
 582                move |this, diff, event, cx| match event {
 583                    BufferDiffEvent::DiffChanged(DiffChanged {
 584                        changed_range: _,
 585                        base_text_changed_range,
 586                        extended_range: _,
 587                    }) => {
 588                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 589                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 590                        }
 591                        cx.emit(Event::BufferDiffChanged);
 592                    }
 593                    BufferDiffEvent::LanguageChanged => {
 594                        this.inverted_buffer_diff_language_changed(diff, cx)
 595                    }
 596                    _ => {}
 597                }
 598            }),
 599            diff,
 600            is_inverted: true,
 601        }
 602    }
 603}
 604
 605/// The contents of a [`MultiBuffer`] at a single point in time.
 606#[derive(Clone, Default)]
 607pub struct MultiBufferSnapshot {
 608    excerpts: SumTree<Excerpt>,
 609    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 610    diff_transforms: SumTree<DiffTransform>,
 611    non_text_state_update_count: usize,
 612    edit_count: usize,
 613    is_dirty: bool,
 614    has_deleted_file: bool,
 615    has_conflict: bool,
 616    has_inverted_diff: bool,
 617    /// immutable fields
 618    singleton: bool,
 619    excerpt_ids: SumTree<ExcerptIdMapping>,
 620    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 621    trailing_excerpt_update_count: usize,
 622    all_diff_hunks_expanded: bool,
 623    show_deleted_hunks: bool,
 624    use_extended_diff_range: bool,
 625    show_headers: bool,
 626}
 627
 628// follower: None
 629// - BufferContent(Some)
 630// - BufferContent(None)
 631// - DeletedHunk
 632//
 633// follower: Some
 634// - BufferContent(Some)
 635// - BufferContent(None)
 636
 637#[derive(Debug, Clone)]
 638enum DiffTransform {
 639    // RealText
 640    BufferContent {
 641        summary: MBTextSummary,
 642        // modified_hunk_info
 643        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 644    },
 645    // ExpandedHunkText
 646    DeletedHunk {
 647        summary: TextSummary,
 648        buffer_id: BufferId,
 649        hunk_info: DiffTransformHunkInfo,
 650        base_text_byte_range: Range<usize>,
 651        has_trailing_newline: bool,
 652    },
 653}
 654
 655#[derive(Clone, Copy, Debug)]
 656struct DiffTransformHunkInfo {
 657    excerpt_id: ExcerptId,
 658    hunk_start_anchor: text::Anchor,
 659    hunk_secondary_status: DiffHunkSecondaryStatus,
 660    is_logically_deleted: bool,
 661}
 662
 663impl Eq for DiffTransformHunkInfo {}
 664
 665impl PartialEq for DiffTransformHunkInfo {
 666    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 667        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 668    }
 669}
 670
 671impl std::hash::Hash for DiffTransformHunkInfo {
 672    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 673        self.excerpt_id.hash(state);
 674        self.hunk_start_anchor.hash(state);
 675    }
 676}
 677
 678#[derive(Clone)]
 679pub struct ExcerptInfo {
 680    pub id: ExcerptId,
 681    pub buffer: Arc<BufferSnapshot>,
 682    pub buffer_id: BufferId,
 683    pub range: ExcerptRange<text::Anchor>,
 684    pub end_row: MultiBufferRow,
 685}
 686
 687impl std::fmt::Debug for ExcerptInfo {
 688    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 689        f.debug_struct(type_name::<Self>())
 690            .field("id", &self.id)
 691            .field("buffer_id", &self.buffer_id)
 692            .field("path", &self.buffer.file().map(|f| f.path()))
 693            .field("range", &self.range)
 694            .finish()
 695    }
 696}
 697
 698/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 699#[derive(Debug)]
 700pub struct ExcerptBoundary {
 701    pub prev: Option<ExcerptInfo>,
 702    pub next: ExcerptInfo,
 703    /// The row in the `MultiBuffer` where the boundary is located
 704    pub row: MultiBufferRow,
 705}
 706
 707impl ExcerptBoundary {
 708    pub fn starts_new_buffer(&self) -> bool {
 709        match (self.prev.as_ref(), &self.next) {
 710            (None, _) => true,
 711            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 712        }
 713    }
 714}
 715
 716#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 717pub struct ExpandInfo {
 718    pub direction: ExpandExcerptDirection,
 719    pub excerpt_id: ExcerptId,
 720}
 721
 722#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 723pub struct RowInfo {
 724    pub buffer_id: Option<BufferId>,
 725    pub buffer_row: Option<u32>,
 726    pub multibuffer_row: Option<MultiBufferRow>,
 727    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 728    pub expand_info: Option<ExpandInfo>,
 729    pub wrapped_buffer_row: Option<u32>,
 730}
 731
 732/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 733#[derive(Clone)]
 734struct Excerpt {
 735    /// The unique identifier for this excerpt
 736    id: ExcerptId,
 737    /// The location of the excerpt in the [`MultiBuffer`]
 738    locator: Locator,
 739    /// The buffer being excerpted
 740    buffer_id: BufferId,
 741    /// A snapshot of the buffer being excerpted
 742    buffer: Arc<BufferSnapshot>,
 743    /// The range of the buffer to be shown in the excerpt
 744    range: ExcerptRange<text::Anchor>,
 745    /// The last row in the excerpted slice of the buffer
 746    max_buffer_row: BufferRow,
 747    /// A summary of the text in the excerpt
 748    text_summary: TextSummary,
 749    has_trailing_newline: bool,
 750}
 751
 752/// A public view into an `Excerpt` in a [`MultiBuffer`].
 753///
 754/// Contains methods for getting the [`Buffer`] of the excerpt,
 755/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 756#[derive(Clone)]
 757pub struct MultiBufferExcerpt<'a> {
 758    excerpt: &'a Excerpt,
 759    diff_transforms:
 760        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 761    /// The offset in the multibuffer considering diff transforms.
 762    offset: MultiBufferOffset,
 763    /// The offset in the multibuffer without diff transforms.
 764    excerpt_offset: ExcerptOffset,
 765    buffer_offset: BufferOffset,
 766}
 767
 768#[derive(Clone, Debug)]
 769struct ExcerptIdMapping {
 770    id: ExcerptId,
 771    locator: Locator,
 772}
 773
 774/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 775/// These ranges are relative to the buffer itself
 776#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 777pub struct ExcerptRange<T> {
 778    /// The full range of text to be shown in the excerpt.
 779    pub context: Range<T>,
 780    /// The primary range of text to be highlighted in the excerpt.
 781    /// In a multi-buffer search, this would be the text that matched the search
 782    pub primary: Range<T>,
 783}
 784
 785impl<T: Clone> ExcerptRange<T> {
 786    pub fn new(context: Range<T>) -> Self {
 787        Self {
 788            context: context.clone(),
 789            primary: context,
 790        }
 791    }
 792}
 793
 794#[derive(Clone, Debug, Default)]
 795pub struct ExcerptSummary {
 796    excerpt_id: ExcerptId,
 797    /// The location of the last [`Excerpt`] being summarized
 798    excerpt_locator: Locator,
 799    widest_line_number: u32,
 800    text: MBTextSummary,
 801}
 802
 803#[derive(Debug, Clone)]
 804pub struct DiffTransformSummary {
 805    input: MBTextSummary,
 806    output: MBTextSummary,
 807}
 808
 809/// Summary of a string of text.
 810#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 811pub struct MBTextSummary {
 812    /// Length in bytes.
 813    pub len: MultiBufferOffset,
 814    /// Length in UTF-8.
 815    pub chars: usize,
 816    /// Length in UTF-16 code units
 817    pub len_utf16: OffsetUtf16,
 818    /// A point representing the number of lines and the length of the last line.
 819    ///
 820    /// In other words, it marks the point after the last byte in the text, (if
 821    /// EOF was a character, this would be its position).
 822    pub lines: Point,
 823    /// How many `char`s are in the first line
 824    pub first_line_chars: u32,
 825    /// How many `char`s are in the last line
 826    pub last_line_chars: u32,
 827    /// How many UTF-16 code units are in the last line
 828    pub last_line_len_utf16: u32,
 829    /// The row idx of the longest row
 830    pub longest_row: u32,
 831    /// How many `char`s are in the longest row
 832    pub longest_row_chars: u32,
 833}
 834
 835impl From<TextSummary> for MBTextSummary {
 836    fn from(summary: TextSummary) -> Self {
 837        MBTextSummary {
 838            len: MultiBufferOffset(summary.len),
 839            chars: summary.chars,
 840            len_utf16: summary.len_utf16,
 841            lines: summary.lines,
 842            first_line_chars: summary.first_line_chars,
 843            last_line_chars: summary.last_line_chars,
 844            last_line_len_utf16: summary.last_line_len_utf16,
 845            longest_row: summary.longest_row,
 846            longest_row_chars: summary.longest_row_chars,
 847        }
 848    }
 849}
 850
 851impl From<MBTextSummary> for TextSummary {
 852    fn from(summary: MBTextSummary) -> Self {
 853        TextSummary {
 854            len: summary.len.0,
 855            chars: summary.chars,
 856            len_utf16: summary.len_utf16,
 857            lines: summary.lines,
 858            first_line_chars: summary.first_line_chars,
 859            last_line_chars: summary.last_line_chars,
 860            last_line_len_utf16: summary.last_line_len_utf16,
 861            longest_row: summary.longest_row,
 862            longest_row_chars: summary.longest_row_chars,
 863        }
 864    }
 865}
 866
 867impl From<&str> for MBTextSummary {
 868    fn from(text: &str) -> Self {
 869        MBTextSummary::from(TextSummary::from(text))
 870    }
 871}
 872
 873impl MultiBufferDimension for MBTextSummary {
 874    type TextDimension = TextSummary;
 875
 876    fn from_summary(summary: &MBTextSummary) -> Self {
 877        *summary
 878    }
 879
 880    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 881        *self += *summary;
 882    }
 883
 884    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 885        *self += *summary;
 886    }
 887}
 888
 889impl AddAssign for MBTextSummary {
 890    fn add_assign(&mut self, other: MBTextSummary) {
 891        let joined_chars = self.last_line_chars + other.first_line_chars;
 892        if joined_chars > self.longest_row_chars {
 893            self.longest_row = self.lines.row;
 894            self.longest_row_chars = joined_chars;
 895        }
 896        if other.longest_row_chars > self.longest_row_chars {
 897            self.longest_row = self.lines.row + other.longest_row;
 898            self.longest_row_chars = other.longest_row_chars;
 899        }
 900
 901        if self.lines.row == 0 {
 902            self.first_line_chars += other.first_line_chars;
 903        }
 904
 905        if other.lines.row == 0 {
 906            self.last_line_chars += other.first_line_chars;
 907            self.last_line_len_utf16 += other.last_line_len_utf16;
 908        } else {
 909            self.last_line_chars = other.last_line_chars;
 910            self.last_line_len_utf16 = other.last_line_len_utf16;
 911        }
 912
 913        self.chars += other.chars;
 914        self.len += other.len;
 915        self.len_utf16 += other.len_utf16;
 916        self.lines += other.lines;
 917    }
 918}
 919
 920impl AddAssign<TextSummary> for MBTextSummary {
 921    fn add_assign(&mut self, other: TextSummary) {
 922        *self += MBTextSummary::from(other);
 923    }
 924}
 925
 926impl MBTextSummary {
 927    pub fn lines_utf16(&self) -> PointUtf16 {
 928        PointUtf16 {
 929            row: self.lines.row,
 930            column: self.last_line_len_utf16,
 931        }
 932    }
 933}
 934
 935impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 936where
 937    K: MultiBufferDimension,
 938    V: MultiBufferDimension,
 939{
 940    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 941
 942    fn from_summary(summary: &MBTextSummary) -> Self {
 943        Self {
 944            key: K::from_summary(summary),
 945            value: Some(V::from_summary(summary)),
 946        }
 947    }
 948
 949    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 950        self.key.add_text_dim(&summary.key);
 951        if let Some(value) = &mut self.value {
 952            if let Some(other_value) = summary.value.as_ref() {
 953                value.add_text_dim(other_value);
 954            }
 955        }
 956    }
 957
 958    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 959        self.key.add_mb_text_summary(summary);
 960        if let Some(value) = &mut self.value {
 961            value.add_mb_text_summary(summary);
 962        }
 963    }
 964}
 965
 966#[derive(Clone)]
 967pub struct MultiBufferRows<'a> {
 968    point: Point,
 969    is_empty: bool,
 970    is_singleton: bool,
 971    cursor: MultiBufferCursor<'a, Point, Point>,
 972}
 973
 974pub struct MultiBufferChunks<'a> {
 975    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 976    diff_transforms:
 977        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 978    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 979    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 980    buffer_chunk: Option<Chunk<'a>>,
 981    range: Range<MultiBufferOffset>,
 982    excerpt_offset_range: Range<ExcerptOffset>,
 983    excerpt_chunks: Option<ExcerptChunks<'a>>,
 984    language_aware: bool,
 985}
 986
 987pub struct ReversedMultiBufferChunks<'a> {
 988    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 989    current_chunks: Option<rope::Chunks<'a>>,
 990    start: MultiBufferOffset,
 991    offset: MultiBufferOffset,
 992}
 993
 994pub struct MultiBufferBytes<'a> {
 995    range: Range<MultiBufferOffset>,
 996    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 997    excerpt_bytes: Option<text::Bytes<'a>>,
 998    has_trailing_newline: bool,
 999    chunk: &'a [u8],
1000}
1001
1002pub struct ReversedMultiBufferBytes<'a> {
1003    range: Range<MultiBufferOffset>,
1004    chunks: ReversedMultiBufferChunks<'a>,
1005    chunk: &'a [u8],
1006}
1007
1008#[derive(Clone)]
1009struct DiffTransforms<MBD> {
1010    output_dimension: OutputDimension<MBD>,
1011    excerpt_dimension: ExcerptDimension<MBD>,
1012}
1013
1014impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1015    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1016        Self {
1017            output_dimension: OutputDimension::zero(cx),
1018            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1019                cx,
1020            ),
1021        }
1022    }
1023
1024    fn add_summary(
1025        &mut self,
1026        summary: &'a DiffTransformSummary,
1027        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1028    ) {
1029        self.output_dimension.add_summary(summary, cx);
1030        self.excerpt_dimension.add_summary(summary, cx);
1031    }
1032}
1033
1034#[derive(Clone)]
1035struct MultiBufferCursor<'a, MBD, BD> {
1036    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1037    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1038    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1039    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1040}
1041
1042#[derive(Clone)]
1043struct MultiBufferRegion<'a, MBD, BD> {
1044    buffer: &'a BufferSnapshot,
1045    is_main_buffer: bool,
1046    diff_hunk_status: Option<DiffHunkStatus>,
1047    excerpt: &'a Excerpt,
1048    buffer_range: Range<BD>,
1049    range: Range<MBD>,
1050    has_trailing_newline: bool,
1051}
1052
1053struct ExcerptChunks<'a> {
1054    excerpt_id: ExcerptId,
1055    content_chunks: BufferChunks<'a>,
1056    has_footer: bool,
1057}
1058
1059#[derive(Debug)]
1060struct BufferEdit {
1061    range: Range<BufferOffset>,
1062    new_text: Arc<str>,
1063    is_insertion: bool,
1064    original_indent_column: Option<u32>,
1065    excerpt_id: ExcerptId,
1066}
1067
1068#[derive(Clone, Copy, Debug, PartialEq)]
1069enum DiffChangeKind {
1070    BufferEdited,
1071    DiffUpdated { base_changed: bool },
1072    ExpandOrCollapseHunks { expand: bool },
1073}
1074
1075#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1076pub enum ExpandExcerptDirection {
1077    Up,
1078    Down,
1079    UpAndDown,
1080}
1081
1082impl ExpandExcerptDirection {
1083    pub fn should_expand_up(&self) -> bool {
1084        match self {
1085            ExpandExcerptDirection::Up => true,
1086            ExpandExcerptDirection::Down => false,
1087            ExpandExcerptDirection::UpAndDown => true,
1088        }
1089    }
1090
1091    pub fn should_expand_down(&self) -> bool {
1092        match self {
1093            ExpandExcerptDirection::Up => false,
1094            ExpandExcerptDirection::Down => true,
1095            ExpandExcerptDirection::UpAndDown => true,
1096        }
1097    }
1098}
1099
1100#[derive(Clone, Debug, PartialEq)]
1101pub struct IndentGuide {
1102    pub buffer_id: BufferId,
1103    pub start_row: MultiBufferRow,
1104    pub end_row: MultiBufferRow,
1105    pub depth: u32,
1106    pub tab_size: u32,
1107    pub settings: IndentGuideSettings,
1108}
1109
1110impl IndentGuide {
1111    pub fn indent_level(&self) -> u32 {
1112        self.depth * self.tab_size
1113    }
1114}
1115
1116impl MultiBuffer {
1117    pub fn new(capability: Capability) -> Self {
1118        Self::new_(
1119            capability,
1120            MultiBufferSnapshot {
1121                show_headers: true,
1122                show_deleted_hunks: true,
1123                ..MultiBufferSnapshot::default()
1124            },
1125        )
1126    }
1127
1128    pub fn without_headers(capability: Capability) -> Self {
1129        Self::new_(
1130            capability,
1131            MultiBufferSnapshot {
1132                show_deleted_hunks: true,
1133                ..MultiBufferSnapshot::default()
1134            },
1135        )
1136    }
1137
1138    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1139        let mut this = Self::new_(
1140            buffer.read(cx).capability(),
1141            MultiBufferSnapshot {
1142                singleton: true,
1143                show_deleted_hunks: true,
1144                ..MultiBufferSnapshot::default()
1145            },
1146        );
1147        this.singleton = true;
1148        let buffer_id = buffer.read(cx).remote_id();
1149        this.push_excerpts(
1150            buffer,
1151            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1152                buffer_id,
1153            ))],
1154            cx,
1155        );
1156        this
1157    }
1158
1159    #[inline]
1160    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1161        Self {
1162            snapshot: RefCell::new(snapshot),
1163            buffers: Default::default(),
1164            diffs: HashMap::default(),
1165            subscriptions: Topic::default(),
1166            singleton: false,
1167            capability,
1168            title: None,
1169            excerpts_by_path: Default::default(),
1170            paths_by_excerpt: Default::default(),
1171            buffer_changed_since_sync: Default::default(),
1172            history: History::default(),
1173        }
1174    }
1175
1176    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1177        let mut buffers = BTreeMap::default();
1178        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1179        for (buffer_id, buffer_state) in self.buffers.iter() {
1180            buffer_state.buffer.update(new_cx, |buffer, _| {
1181                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1182            });
1183            buffers.insert(
1184                *buffer_id,
1185                BufferState {
1186                    buffer: buffer_state.buffer.clone(),
1187                    last_version: buffer_state.last_version.clone(),
1188                    last_non_text_state_update_count: buffer_state
1189                        .last_non_text_state_update_count
1190                        .clone(),
1191                    excerpts: buffer_state.excerpts.clone(),
1192                    _subscriptions: [
1193                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1194                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1195                    ],
1196                },
1197            );
1198        }
1199        let mut diff_bases = HashMap::default();
1200        for (buffer_id, diff) in self.diffs.iter() {
1201            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1202        }
1203        Self {
1204            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1205            buffers: buffers,
1206            excerpts_by_path: Default::default(),
1207            paths_by_excerpt: Default::default(),
1208            diffs: diff_bases,
1209            subscriptions: Default::default(),
1210            singleton: self.singleton,
1211            capability: self.capability,
1212            history: self.history.clone(),
1213            title: self.title.clone(),
1214            buffer_changed_since_sync,
1215        }
1216    }
1217
1218    pub fn set_group_interval(&mut self, group_interval: Duration) {
1219        self.history.set_group_interval(group_interval);
1220    }
1221
1222    pub fn with_title(mut self, title: String) -> Self {
1223        self.title = Some(title);
1224        self
1225    }
1226
1227    pub fn read_only(&self) -> bool {
1228        !self.capability.editable()
1229    }
1230
1231    pub fn capability(&self) -> Capability {
1232        self.capability
1233    }
1234
1235    /// Returns an up-to-date snapshot of the MultiBuffer.
1236    #[ztracing::instrument(skip_all)]
1237    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1238        self.sync(cx);
1239        self.snapshot.borrow().clone()
1240    }
1241
1242    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1243        self.sync(cx);
1244        self.snapshot.borrow()
1245    }
1246
1247    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1248        if self.singleton {
1249            Some(self.buffers.values().next().unwrap().buffer.clone())
1250        } else {
1251            None
1252        }
1253    }
1254
1255    pub fn is_singleton(&self) -> bool {
1256        self.singleton
1257    }
1258
1259    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1260        self.subscriptions.subscribe()
1261    }
1262
1263    pub fn is_dirty(&self, cx: &App) -> bool {
1264        self.read(cx).is_dirty()
1265    }
1266
1267    pub fn has_deleted_file(&self, cx: &App) -> bool {
1268        self.read(cx).has_deleted_file()
1269    }
1270
1271    pub fn has_conflict(&self, cx: &App) -> bool {
1272        self.read(cx).has_conflict()
1273    }
1274
1275    // The `is_empty` signature doesn't match what clippy expects
1276    #[allow(clippy::len_without_is_empty)]
1277    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1278        self.read(cx).len()
1279    }
1280
1281    pub fn is_empty(&self) -> bool {
1282        self.buffers.is_empty()
1283    }
1284
1285    pub fn edit<I, S, T>(
1286        &mut self,
1287        edits: I,
1288        autoindent_mode: Option<AutoindentMode>,
1289        cx: &mut Context<Self>,
1290    ) where
1291        I: IntoIterator<Item = (Range<S>, T)>,
1292        S: ToOffset,
1293        T: Into<Arc<str>>,
1294    {
1295        self.edit_internal(edits, autoindent_mode, true, cx);
1296    }
1297
1298    pub fn edit_non_coalesce<I, S, T>(
1299        &mut self,
1300        edits: I,
1301        autoindent_mode: Option<AutoindentMode>,
1302        cx: &mut Context<Self>,
1303    ) where
1304        I: IntoIterator<Item = (Range<S>, T)>,
1305        S: ToOffset,
1306        T: Into<Arc<str>>,
1307    {
1308        self.edit_internal(edits, autoindent_mode, false, cx);
1309    }
1310
1311    fn edit_internal<I, S, T>(
1312        &mut self,
1313        edits: I,
1314        autoindent_mode: Option<AutoindentMode>,
1315        coalesce_adjacent: bool,
1316        cx: &mut Context<Self>,
1317    ) where
1318        I: IntoIterator<Item = (Range<S>, T)>,
1319        S: ToOffset,
1320        T: Into<Arc<str>>,
1321    {
1322        if self.read_only() || self.buffers.is_empty() {
1323            return;
1324        }
1325        self.sync_mut(cx);
1326        let edits = edits
1327            .into_iter()
1328            .map(|(range, new_text)| {
1329                let mut range = range.start.to_offset(self.snapshot.get_mut())
1330                    ..range.end.to_offset(self.snapshot.get_mut());
1331                if range.start > range.end {
1332                    mem::swap(&mut range.start, &mut range.end);
1333                }
1334                (range, new_text.into())
1335            })
1336            .collect::<Vec<_>>();
1337
1338        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1339
1340        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1341        fn edit_internal(
1342            this: &mut MultiBuffer,
1343            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1344            mut autoindent_mode: Option<AutoindentMode>,
1345            coalesce_adjacent: bool,
1346            cx: &mut Context<MultiBuffer>,
1347        ) {
1348            let original_indent_columns = match &mut autoindent_mode {
1349                Some(AutoindentMode::Block {
1350                    original_indent_columns,
1351                }) => mem::take(original_indent_columns),
1352                _ => Default::default(),
1353            };
1354
1355            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1356                edits,
1357                this.snapshot.get_mut(),
1358                &original_indent_columns,
1359            );
1360
1361            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1362            for (buffer_id, mut edits) in buffer_edits {
1363                buffer_ids.push(buffer_id);
1364                edits.sort_by_key(|edit| edit.range.start);
1365                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1366                    let mut edits = edits.into_iter().peekable();
1367                    let mut insertions = Vec::new();
1368                    let mut original_indent_columns = Vec::new();
1369                    let mut deletions = Vec::new();
1370                    let empty_str: Arc<str> = Arc::default();
1371                    while let Some(BufferEdit {
1372                        mut range,
1373                        mut new_text,
1374                        mut is_insertion,
1375                        original_indent_column,
1376                        excerpt_id,
1377                    }) = edits.next()
1378                    {
1379                        while let Some(BufferEdit {
1380                            range: next_range,
1381                            is_insertion: next_is_insertion,
1382                            new_text: next_new_text,
1383                            excerpt_id: next_excerpt_id,
1384                            ..
1385                        }) = edits.peek()
1386                        {
1387                            let should_coalesce = if coalesce_adjacent {
1388                                range.end >= next_range.start
1389                            } else {
1390                                range.end > next_range.start
1391                            };
1392
1393                            if should_coalesce {
1394                                range.end = cmp::max(next_range.end, range.end);
1395                                is_insertion |= *next_is_insertion;
1396                                if excerpt_id == *next_excerpt_id {
1397                                    new_text = format!("{new_text}{next_new_text}").into();
1398                                }
1399                                edits.next();
1400                            } else {
1401                                break;
1402                            }
1403                        }
1404
1405                        if is_insertion {
1406                            original_indent_columns.push(original_indent_column);
1407                            insertions.push((
1408                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1409                                new_text.clone(),
1410                            ));
1411                        } else if !range.is_empty() {
1412                            deletions.push((
1413                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1414                                empty_str.clone(),
1415                            ));
1416                        }
1417                    }
1418
1419                    let deletion_autoindent_mode =
1420                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1421                            Some(AutoindentMode::Block {
1422                                original_indent_columns: Default::default(),
1423                            })
1424                        } else {
1425                            autoindent_mode.clone()
1426                        };
1427                    let insertion_autoindent_mode =
1428                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1429                            Some(AutoindentMode::Block {
1430                                original_indent_columns,
1431                            })
1432                        } else {
1433                            autoindent_mode.clone()
1434                        };
1435
1436                    if coalesce_adjacent {
1437                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1438                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1439                    } else {
1440                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1441                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1442                    }
1443                })
1444            }
1445
1446            cx.emit(Event::ExcerptsEdited {
1447                excerpt_ids: edited_excerpt_ids,
1448                buffer_ids,
1449            });
1450        }
1451    }
1452
1453    fn convert_edits_to_buffer_edits(
1454        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1455        snapshot: &MultiBufferSnapshot,
1456        original_indent_columns: &[Option<u32>],
1457    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1458        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1459        let mut edited_excerpt_ids = Vec::new();
1460        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1461        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1462            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1463
1464            cursor.seek(&range.start);
1465            let mut start_region = cursor.region().expect("start offset out of bounds");
1466            if !start_region.is_main_buffer {
1467                cursor.next();
1468                if let Some(region) = cursor.region() {
1469                    start_region = region;
1470                } else {
1471                    continue;
1472                }
1473            }
1474
1475            if range.end < start_region.range.start {
1476                continue;
1477            }
1478
1479            let start_region = start_region.clone();
1480            if range.end > start_region.range.end {
1481                cursor.seek_forward(&range.end);
1482            }
1483            let mut end_region = cursor.region().expect("end offset out of bounds");
1484            if !end_region.is_main_buffer {
1485                cursor.prev();
1486                if let Some(region) = cursor.region() {
1487                    end_region = region;
1488                } else {
1489                    continue;
1490                }
1491            }
1492
1493            if range.start > end_region.range.end {
1494                continue;
1495            }
1496
1497            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1498            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1499            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1500                .min(start_region.buffer_range.end);
1501            let buffer_end =
1502                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1503
1504            if start_region.excerpt.id == end_region.excerpt.id {
1505                if start_region.buffer.capability == Capability::ReadWrite
1506                    && start_region.is_main_buffer
1507                {
1508                    edited_excerpt_ids.push(start_region.excerpt.id);
1509                    buffer_edits
1510                        .entry(start_region.buffer.remote_id())
1511                        .or_default()
1512                        .push(BufferEdit {
1513                            range: buffer_start..buffer_end,
1514                            new_text,
1515                            is_insertion: true,
1516                            original_indent_column,
1517                            excerpt_id: start_region.excerpt.id,
1518                        });
1519                }
1520            } else {
1521                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1522                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1523                if start_region.buffer.capability == Capability::ReadWrite
1524                    && start_region.is_main_buffer
1525                {
1526                    edited_excerpt_ids.push(start_region.excerpt.id);
1527                    buffer_edits
1528                        .entry(start_region.buffer.remote_id())
1529                        .or_default()
1530                        .push(BufferEdit {
1531                            range: start_excerpt_range,
1532                            new_text: new_text.clone(),
1533                            is_insertion: true,
1534                            original_indent_column,
1535                            excerpt_id: start_region.excerpt.id,
1536                        });
1537                }
1538                let excerpt_id = end_region.excerpt.id;
1539                if end_region.buffer.capability == Capability::ReadWrite
1540                    && end_region.is_main_buffer
1541                {
1542                    edited_excerpt_ids.push(excerpt_id);
1543                    buffer_edits
1544                        .entry(end_region.buffer.remote_id())
1545                        .or_default()
1546                        .push(BufferEdit {
1547                            range: end_excerpt_range,
1548                            new_text: new_text.clone(),
1549                            is_insertion: false,
1550                            original_indent_column,
1551                            excerpt_id,
1552                        });
1553                }
1554
1555                cursor.seek(&range.start);
1556                cursor.next_excerpt();
1557                while let Some(region) = cursor.region() {
1558                    if region.excerpt.id == excerpt_id {
1559                        break;
1560                    }
1561                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1562                        edited_excerpt_ids.push(region.excerpt.id);
1563                        buffer_edits
1564                            .entry(region.buffer.remote_id())
1565                            .or_default()
1566                            .push(BufferEdit {
1567                                range: region.buffer_range.clone(),
1568                                new_text: new_text.clone(),
1569                                is_insertion: false,
1570                                original_indent_column,
1571                                excerpt_id: region.excerpt.id,
1572                            });
1573                    }
1574                    cursor.next_excerpt();
1575                }
1576            }
1577        }
1578        (buffer_edits, edited_excerpt_ids)
1579    }
1580
1581    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1582    where
1583        I: IntoIterator<Item = Range<S>>,
1584        S: ToOffset,
1585    {
1586        if self.read_only() || self.buffers.is_empty() {
1587            return;
1588        }
1589        self.sync_mut(cx);
1590        let empty = Arc::<str>::from("");
1591        let edits = ranges
1592            .into_iter()
1593            .map(|range| {
1594                let mut range = range.start.to_offset(self.snapshot.get_mut())
1595                    ..range.end.to_offset(&self.snapshot.get_mut());
1596                if range.start > range.end {
1597                    mem::swap(&mut range.start, &mut range.end);
1598                }
1599                (range, empty.clone())
1600            })
1601            .collect::<Vec<_>>();
1602
1603        return autoindent_ranges_internal(self, edits, cx);
1604
1605        fn autoindent_ranges_internal(
1606            this: &mut MultiBuffer,
1607            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1608            cx: &mut Context<MultiBuffer>,
1609        ) {
1610            let (buffer_edits, edited_excerpt_ids) =
1611                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1612
1613            let mut buffer_ids = Vec::new();
1614            for (buffer_id, mut edits) in buffer_edits {
1615                buffer_ids.push(buffer_id);
1616                edits.sort_unstable_by_key(|edit| edit.range.start);
1617
1618                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1619                for edit in edits {
1620                    if let Some(last_range) = ranges.last_mut()
1621                        && edit.range.start <= last_range.end
1622                    {
1623                        last_range.end = last_range.end.max(edit.range.end);
1624                        continue;
1625                    }
1626                    ranges.push(edit.range);
1627                }
1628
1629                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1630                    buffer.autoindent_ranges(ranges, cx);
1631                })
1632            }
1633
1634            cx.emit(Event::ExcerptsEdited {
1635                excerpt_ids: edited_excerpt_ids,
1636                buffer_ids,
1637            });
1638        }
1639    }
1640
1641    pub fn set_active_selections(
1642        &self,
1643        selections: &[Selection<Anchor>],
1644        line_mode: bool,
1645        cursor_shape: CursorShape,
1646        cx: &mut Context<Self>,
1647    ) {
1648        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1649            Default::default();
1650        let snapshot = self.read(cx);
1651        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1652        for selection in selections {
1653            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1654            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1655
1656            cursor.seek(&Some(start_locator), Bias::Left);
1657            while let Some(excerpt) = cursor.item()
1658                && excerpt.locator <= *end_locator
1659            {
1660                let mut start = excerpt.range.context.start;
1661                let mut end = excerpt.range.context.end;
1662                if excerpt.id == selection.start.excerpt_id {
1663                    start = selection.start.text_anchor;
1664                }
1665                if excerpt.id == selection.end.excerpt_id {
1666                    end = selection.end.text_anchor;
1667                }
1668                selections_by_buffer
1669                    .entry(excerpt.buffer_id)
1670                    .or_default()
1671                    .push(Selection {
1672                        id: selection.id,
1673                        start,
1674                        end,
1675                        reversed: selection.reversed,
1676                        goal: selection.goal,
1677                    });
1678
1679                cursor.next();
1680            }
1681        }
1682
1683        for (buffer_id, buffer_state) in self.buffers.iter() {
1684            if !selections_by_buffer.contains_key(buffer_id) {
1685                buffer_state
1686                    .buffer
1687                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1688            }
1689        }
1690
1691        for (buffer_id, mut selections) in selections_by_buffer {
1692            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1693                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1694                let mut selections = selections.into_iter().peekable();
1695                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1696                    let mut selection = selections.next()?;
1697                    while let Some(next_selection) = selections.peek() {
1698                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1699                            let next_selection = selections.next().unwrap();
1700                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1701                                selection.end = next_selection.end;
1702                            }
1703                        } else {
1704                            break;
1705                        }
1706                    }
1707                    Some(selection)
1708                }));
1709                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1710            });
1711        }
1712    }
1713
1714    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1715        for buffer in self.buffers.values() {
1716            buffer
1717                .buffer
1718                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1719        }
1720    }
1721
1722    pub fn push_excerpts<O>(
1723        &mut self,
1724        buffer: Entity<Buffer>,
1725        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1726        cx: &mut Context<Self>,
1727    ) -> Vec<ExcerptId>
1728    where
1729        O: text::ToOffset,
1730    {
1731        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1732    }
1733
1734    #[instrument(skip_all)]
1735    fn merge_excerpt_ranges<'a>(
1736        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1737    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1738        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1739        let mut counts: Vec<usize> = Vec::new();
1740        for range in expanded_ranges {
1741            if let Some(last_range) = merged_ranges.last_mut() {
1742                assert!(
1743                    last_range.context.start <= range.context.start,
1744                    "ranges must be sorted: {last_range:?} <= {range:?}"
1745                );
1746                if last_range.context.end >= range.context.start
1747                    || last_range.context.end.row + 1 == range.context.start.row
1748                {
1749                    last_range.context.end = range.context.end.max(last_range.context.end);
1750                    *counts.last_mut().unwrap() += 1;
1751                    continue;
1752                }
1753            }
1754            merged_ranges.push(range.clone());
1755            counts.push(1);
1756        }
1757        (merged_ranges, counts)
1758    }
1759
1760    pub fn insert_excerpts_after<O>(
1761        &mut self,
1762        prev_excerpt_id: ExcerptId,
1763        buffer: Entity<Buffer>,
1764        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1765        cx: &mut Context<Self>,
1766    ) -> Vec<ExcerptId>
1767    where
1768        O: text::ToOffset,
1769    {
1770        let mut ids = Vec::new();
1771        let mut next_excerpt_id =
1772            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1773                last_entry.id.0 + 1
1774            } else {
1775                1
1776            };
1777        self.insert_excerpts_with_ids_after(
1778            prev_excerpt_id,
1779            buffer,
1780            ranges.into_iter().map(|range| {
1781                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1782                ids.push(id);
1783                (id, range)
1784            }),
1785            cx,
1786        );
1787        ids
1788    }
1789
1790    pub fn insert_excerpts_with_ids_after<O>(
1791        &mut self,
1792        prev_excerpt_id: ExcerptId,
1793        buffer: Entity<Buffer>,
1794        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1795        cx: &mut Context<Self>,
1796    ) where
1797        O: text::ToOffset,
1798    {
1799        assert_eq!(self.history.transaction_depth(), 0);
1800        let mut ranges = ranges.into_iter().peekable();
1801        if ranges.peek().is_none() {
1802            return Default::default();
1803        }
1804
1805        self.sync_mut(cx);
1806
1807        let buffer_snapshot = buffer.read(cx).snapshot();
1808        let buffer_id = buffer_snapshot.remote_id();
1809
1810        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1811            self.buffer_changed_since_sync.replace(true);
1812            buffer.update(cx, |buffer, _| {
1813                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1814            });
1815            BufferState {
1816                last_version: RefCell::new(buffer_snapshot.version().clone()),
1817                last_non_text_state_update_count: Cell::new(
1818                    buffer_snapshot.non_text_state_update_count(),
1819                ),
1820                excerpts: Default::default(),
1821                _subscriptions: [
1822                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1823                    cx.subscribe(&buffer, Self::on_buffer_event),
1824                ],
1825                buffer: buffer.clone(),
1826            }
1827        });
1828
1829        let mut snapshot = self.snapshot.get_mut();
1830
1831        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1832        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1833        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1834        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1835        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1836
1837        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1838        new_excerpts.update_last(
1839            |excerpt| {
1840                excerpt.has_trailing_newline = true;
1841            },
1842            (),
1843        );
1844
1845        let next_locator = if let Some(excerpt) = cursor.item() {
1846            excerpt.locator.clone()
1847        } else {
1848            Locator::max()
1849        };
1850
1851        let mut excerpts = Vec::new();
1852        let buffer_snapshot = Arc::new(buffer_snapshot);
1853        while let Some((id, range)) = ranges.next() {
1854            let locator = Locator::between(&prev_locator, &next_locator);
1855            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1856                buffer_state.excerpts.insert(ix, locator.clone());
1857            }
1858            let range = ExcerptRange {
1859                context: buffer_snapshot.anchor_before(&range.context.start)
1860                    ..buffer_snapshot.anchor_after(&range.context.end),
1861                primary: buffer_snapshot.anchor_before(&range.primary.start)
1862                    ..buffer_snapshot.anchor_after(&range.primary.end),
1863            };
1864            excerpts.push((id, range.clone()));
1865            let excerpt = Excerpt::new(
1866                id,
1867                locator.clone(),
1868                buffer_id,
1869                buffer_snapshot.clone(),
1870                range,
1871                ranges.peek().is_some() || cursor.item().is_some(),
1872            );
1873            new_excerpts.push(excerpt, ());
1874            prev_locator = locator.clone();
1875
1876            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1877                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1878            }
1879            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1880        }
1881
1882        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1883
1884        let suffix = cursor.suffix();
1885        let changed_trailing_excerpt = suffix.is_empty();
1886        new_excerpts.append(suffix, ());
1887        drop(cursor);
1888        snapshot.excerpts = new_excerpts;
1889        snapshot.excerpt_ids = new_excerpt_ids;
1890        if changed_trailing_excerpt {
1891            snapshot.trailing_excerpt_update_count += 1;
1892        }
1893
1894        let edits = Self::sync_diff_transforms(
1895            &mut snapshot,
1896            vec![Edit {
1897                old: edit_start..edit_start,
1898                new: edit_start..edit_end,
1899            }],
1900            DiffChangeKind::BufferEdited,
1901        );
1902        if !edits.is_empty() {
1903            self.subscriptions.publish(edits);
1904        }
1905
1906        cx.emit(Event::Edited {
1907            edited_buffer: None,
1908        });
1909        cx.emit(Event::ExcerptsAdded {
1910            buffer,
1911            predecessor: prev_excerpt_id,
1912            excerpts,
1913        });
1914        cx.notify();
1915    }
1916
1917    pub fn clear(&mut self, cx: &mut Context<Self>) {
1918        self.sync_mut(cx);
1919        let ids = self.excerpt_ids();
1920        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1921        self.excerpts_by_path.clear();
1922        self.paths_by_excerpt.clear();
1923        let MultiBufferSnapshot {
1924            excerpts,
1925            diffs: _,
1926            diff_transforms: _,
1927            non_text_state_update_count: _,
1928            edit_count: _,
1929            is_dirty,
1930            has_deleted_file,
1931            has_conflict,
1932            has_inverted_diff,
1933            singleton: _,
1934            excerpt_ids: _,
1935            replaced_excerpts,
1936            trailing_excerpt_update_count,
1937            all_diff_hunks_expanded: _,
1938            show_deleted_hunks: _,
1939            use_extended_diff_range: _,
1940            show_headers: _,
1941        } = self.snapshot.get_mut();
1942        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1943        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1944        *excerpts = Default::default();
1945        *trailing_excerpt_update_count += 1;
1946        *is_dirty = false;
1947        *has_deleted_file = false;
1948        *has_conflict = false;
1949        *has_inverted_diff = false;
1950        replaced_excerpts.clear();
1951
1952        let edits = Self::sync_diff_transforms(
1953            self.snapshot.get_mut(),
1954            vec![Edit {
1955                old: start..prev_len,
1956                new: start..start,
1957            }],
1958            DiffChangeKind::BufferEdited,
1959        );
1960        if !edits.is_empty() {
1961            self.subscriptions.publish(edits);
1962        }
1963        cx.emit(Event::Edited {
1964            edited_buffer: None,
1965        });
1966        cx.emit(Event::ExcerptsRemoved {
1967            ids,
1968            removed_buffer_ids,
1969        });
1970        cx.notify();
1971    }
1972
1973    #[ztracing::instrument(skip_all)]
1974    pub fn excerpts_for_buffer(
1975        &self,
1976        buffer_id: BufferId,
1977        cx: &App,
1978    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1979        let mut excerpts = Vec::new();
1980        let snapshot = self.read(cx);
1981        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1982        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1983            for locator in locators {
1984                cursor.seek_forward(&Some(locator), Bias::Left);
1985                if let Some(excerpt) = cursor.item()
1986                    && excerpt.locator == *locator
1987                {
1988                    excerpts.push((excerpt.id, excerpt.range.clone()));
1989                }
1990            }
1991        }
1992
1993        excerpts
1994    }
1995
1996    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1997        let snapshot = self.read(cx);
1998        let mut excerpts = snapshot
1999            .excerpts
2000            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2001        let mut diff_transforms = snapshot
2002            .diff_transforms
2003            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2004        diff_transforms.next();
2005        let locators = self
2006            .buffers
2007            .get(&buffer_id)
2008            .into_iter()
2009            .flat_map(|state| &state.excerpts);
2010        let mut result = Vec::new();
2011        for locator in locators {
2012            excerpts.seek_forward(&Some(locator), Bias::Left);
2013            if let Some(excerpt) = excerpts.item()
2014                && excerpt.locator == *locator
2015            {
2016                let excerpt_start = excerpts.start().1;
2017                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2018
2019                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2020                let overshoot = excerpt_start - diff_transforms.start().0;
2021                let start = diff_transforms.start().1 + overshoot;
2022
2023                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2024                let overshoot = excerpt_end - diff_transforms.start().0;
2025                let end = diff_transforms.start().1 + overshoot;
2026
2027                result.push(start.0..end.0)
2028            }
2029        }
2030        result
2031    }
2032
2033    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2034        self.snapshot
2035            .borrow()
2036            .excerpts
2037            .iter()
2038            .map(|entry| entry.buffer_id)
2039            .collect()
2040    }
2041
2042    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2043        self.snapshot
2044            .borrow()
2045            .excerpts
2046            .iter()
2047            .map(|entry| entry.id)
2048            .collect()
2049    }
2050
2051    pub fn excerpt_containing(
2052        &self,
2053        position: impl ToOffset,
2054        cx: &App,
2055    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2056        let snapshot = self.read(cx);
2057        let offset = position.to_offset(&snapshot);
2058
2059        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2060        cursor.seek(&offset);
2061        cursor
2062            .excerpt()
2063            .or_else(|| snapshot.excerpts.last())
2064            .map(|excerpt| {
2065                (
2066                    excerpt.id,
2067                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2068                    excerpt.range.context.clone(),
2069                )
2070            })
2071    }
2072
2073    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2074        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2075            self.buffer(buffer_id)
2076        } else {
2077            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2078            Some(buffer)
2079        }
2080    }
2081
2082    // If point is at the end of the buffer, the last excerpt is returned
2083    pub fn point_to_buffer_offset<T: ToOffset>(
2084        &self,
2085        point: T,
2086        cx: &App,
2087    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2088        let snapshot = self.read(cx);
2089        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2090        Some((
2091            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2092            offset,
2093        ))
2094    }
2095
2096    // If point is at the end of the buffer, the last excerpt is returned
2097    pub fn point_to_buffer_point<T: ToPoint>(
2098        &self,
2099        point: T,
2100        cx: &App,
2101    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2102        let snapshot = self.read(cx);
2103        let (buffer, point, is_main_buffer) =
2104            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2105        Some((
2106            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2107            point,
2108            is_main_buffer,
2109        ))
2110    }
2111
2112    pub fn buffer_point_to_anchor(
2113        &self,
2114        buffer: &Entity<Buffer>,
2115        point: Point,
2116        cx: &App,
2117    ) -> Option<Anchor> {
2118        let mut found = None;
2119        let snapshot = buffer.read(cx).snapshot();
2120        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2121            let start = range.context.start.to_point(&snapshot);
2122            let end = range.context.end.to_point(&snapshot);
2123            if start <= point && point < end {
2124                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2125                break;
2126            }
2127            if point < start {
2128                found = Some((start, excerpt_id));
2129            }
2130            if point > end {
2131                found = Some((end, excerpt_id));
2132            }
2133        }
2134
2135        found.map(|(point, excerpt_id)| {
2136            let text_anchor = snapshot.anchor_after(point);
2137            Anchor::in_buffer(excerpt_id, text_anchor)
2138        })
2139    }
2140
2141    pub fn buffer_anchor_to_anchor(
2142        &self,
2143        buffer: &Entity<Buffer>,
2144        anchor: text::Anchor,
2145        cx: &App,
2146    ) -> Option<Anchor> {
2147        let snapshot = buffer.read(cx).snapshot();
2148        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2149            if range.context.start.cmp(&anchor, &snapshot).is_le()
2150                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2151            {
2152                return Some(Anchor::in_buffer(excerpt_id, anchor));
2153            }
2154        }
2155
2156        None
2157    }
2158
2159    pub fn remove_excerpts(
2160        &mut self,
2161        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2162        cx: &mut Context<Self>,
2163    ) {
2164        self.sync_mut(cx);
2165        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2166        if ids.is_empty() {
2167            return;
2168        }
2169        self.buffer_changed_since_sync.replace(true);
2170
2171        let mut snapshot = self.snapshot.get_mut();
2172        let mut new_excerpts = SumTree::default();
2173        let mut cursor = snapshot
2174            .excerpts
2175            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2176        let mut edits = Vec::new();
2177        let mut excerpt_ids = ids.iter().copied().peekable();
2178        let mut removed_buffer_ids = Vec::new();
2179
2180        while let Some(excerpt_id) = excerpt_ids.next() {
2181            self.paths_by_excerpt.remove(&excerpt_id);
2182            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2183            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2184            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2185
2186            if let Some(mut excerpt) = cursor.item() {
2187                if excerpt.id != excerpt_id {
2188                    continue;
2189                }
2190                let mut old_start = cursor.start().1;
2191
2192                // Skip over the removed excerpt.
2193                'remove_excerpts: loop {
2194                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2195                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2196                        if buffer_state.excerpts.is_empty() {
2197                            log::debug!(
2198                                "removing buffer and diff for buffer {}",
2199                                excerpt.buffer_id
2200                            );
2201                            self.buffers.remove(&excerpt.buffer_id);
2202                            removed_buffer_ids.push(excerpt.buffer_id);
2203                        }
2204                    }
2205                    cursor.next();
2206
2207                    // Skip over any subsequent excerpts that are also removed.
2208                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2209                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2210                        if let Some(next_excerpt) = cursor.item()
2211                            && next_excerpt.locator == *next_locator
2212                        {
2213                            excerpt_ids.next();
2214                            excerpt = next_excerpt;
2215                            continue 'remove_excerpts;
2216                        }
2217                    }
2218
2219                    break;
2220                }
2221
2222                // When removing the last excerpt, remove the trailing newline from
2223                // the previous excerpt.
2224                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2225                    old_start -= 1;
2226                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2227                }
2228
2229                // Push an edit for the removal of this run of excerpts.
2230                let old_end = cursor.start().1;
2231                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2232                edits.push(Edit {
2233                    old: old_start..old_end,
2234                    new: new_start..new_start,
2235                });
2236            }
2237        }
2238        let suffix = cursor.suffix();
2239        let changed_trailing_excerpt = suffix.is_empty();
2240        new_excerpts.append(suffix, ());
2241        drop(cursor);
2242        snapshot.excerpts = new_excerpts;
2243        for buffer_id in &removed_buffer_ids {
2244            self.diffs.remove(buffer_id);
2245            snapshot.diffs.remove(buffer_id);
2246        }
2247
2248        // Recalculate has_inverted_diff after removing diffs
2249        if !removed_buffer_ids.is_empty() {
2250            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2251        }
2252
2253        if changed_trailing_excerpt {
2254            snapshot.trailing_excerpt_update_count += 1;
2255        }
2256
2257        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2258        if !edits.is_empty() {
2259            self.subscriptions.publish(edits);
2260        }
2261        cx.emit(Event::Edited {
2262            edited_buffer: None,
2263        });
2264        cx.emit(Event::ExcerptsRemoved {
2265            ids,
2266            removed_buffer_ids,
2267        });
2268        cx.notify();
2269    }
2270
2271    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2272        &self,
2273        anchors: Anchors,
2274        cx: &mut Context<Self>,
2275    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2276        let mut error = None;
2277        let mut futures = Vec::new();
2278        for anchor in anchors {
2279            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2280                if let Some(buffer) = self.buffers.get(&buffer_id) {
2281                    buffer.buffer.update(cx, |buffer, _| {
2282                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2283                    });
2284                } else {
2285                    error = Some(anyhow!(
2286                        "buffer {buffer_id} is not part of this multi-buffer"
2287                    ));
2288                    break;
2289                }
2290            }
2291        }
2292        async move {
2293            if let Some(error) = error {
2294                Err(error)?;
2295            }
2296            for future in futures {
2297                future.await?;
2298            }
2299            Ok(())
2300        }
2301    }
2302
2303    pub fn text_anchor_for_position<T: ToOffset>(
2304        &self,
2305        position: T,
2306        cx: &App,
2307    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2308        let snapshot = self.read(cx);
2309        let anchor = snapshot.anchor_before(position);
2310        let buffer = self
2311            .buffers
2312            .get(&anchor.text_anchor.buffer_id?)?
2313            .buffer
2314            .clone();
2315        Some((buffer, anchor.text_anchor))
2316    }
2317
2318    fn on_buffer_event(
2319        &mut self,
2320        buffer: Entity<Buffer>,
2321        event: &language::BufferEvent,
2322        cx: &mut Context<Self>,
2323    ) {
2324        use language::BufferEvent;
2325        let buffer_id = buffer.read(cx).remote_id();
2326        cx.emit(match event {
2327            BufferEvent::Edited => Event::Edited {
2328                edited_buffer: Some(buffer),
2329            },
2330            BufferEvent::DirtyChanged => Event::DirtyChanged,
2331            BufferEvent::Saved => Event::Saved,
2332            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2333            BufferEvent::Reloaded => Event::Reloaded,
2334            BufferEvent::LanguageChanged(has_language) => {
2335                Event::LanguageChanged(buffer_id, *has_language)
2336            }
2337            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2338            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2339            BufferEvent::CapabilityChanged => {
2340                self.capability = buffer.read(cx).capability();
2341                return;
2342            }
2343            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2344        });
2345    }
2346
2347    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2348        let diff = diff.read(cx);
2349        let buffer_id = diff.buffer_id;
2350        let diff = DiffStateSnapshot {
2351            diff: diff.snapshot(cx),
2352            is_inverted: false,
2353        };
2354        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2355    }
2356
2357    fn inverted_buffer_diff_language_changed(
2358        &mut self,
2359        diff: Entity<BufferDiff>,
2360        cx: &mut Context<Self>,
2361    ) {
2362        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2363        let diff = diff.read(cx);
2364        let diff = DiffStateSnapshot {
2365            diff: diff.snapshot(cx),
2366            is_inverted: true,
2367        };
2368        self.snapshot
2369            .get_mut()
2370            .diffs
2371            .insert(base_text_buffer_id, diff);
2372    }
2373
2374    fn buffer_diff_changed(
2375        &mut self,
2376        diff: Entity<BufferDiff>,
2377        range: Range<text::Anchor>,
2378        cx: &mut Context<Self>,
2379    ) {
2380        self.sync_mut(cx);
2381
2382        let diff = diff.read(cx);
2383        let buffer_id = diff.buffer_id;
2384
2385        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2386            return;
2387        };
2388        let new_diff = DiffStateSnapshot {
2389            diff: diff.snapshot(cx),
2390            is_inverted: false,
2391        };
2392        let mut snapshot = self.snapshot.get_mut();
2393        let base_text_changed = snapshot
2394            .diffs
2395            .get(&buffer_id)
2396            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2397        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2398
2399        let buffer = buffer_state.buffer.read(cx);
2400        let diff_change_range = range.to_offset(buffer);
2401
2402        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2403        let edits = Self::sync_diff_transforms(
2404            &mut snapshot,
2405            excerpt_edits,
2406            DiffChangeKind::DiffUpdated {
2407                base_changed: base_text_changed,
2408            },
2409        );
2410        if !edits.is_empty() {
2411            self.subscriptions.publish(edits);
2412        }
2413        cx.emit(Event::Edited {
2414            edited_buffer: None,
2415        });
2416    }
2417
2418    fn inverted_buffer_diff_changed(
2419        &mut self,
2420        diff: Entity<BufferDiff>,
2421        diff_change_range: Range<usize>,
2422        cx: &mut Context<Self>,
2423    ) {
2424        self.sync_mut(cx);
2425
2426        let diff = diff.read(cx);
2427        let base_text_buffer_id = diff.base_text(cx).remote_id();
2428        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2429            return;
2430        };
2431
2432        let new_diff = DiffStateSnapshot {
2433            diff: diff.snapshot(cx),
2434            is_inverted: true,
2435        };
2436        let mut snapshot = self.snapshot.get_mut();
2437        snapshot
2438            .diffs
2439            .insert_or_replace(base_text_buffer_id, new_diff);
2440
2441        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2442        let edits = Self::sync_diff_transforms(
2443            &mut snapshot,
2444            excerpt_edits,
2445            DiffChangeKind::DiffUpdated {
2446                // We don't read this field for inverted diffs.
2447                base_changed: false,
2448            },
2449        );
2450        if !edits.is_empty() {
2451            self.subscriptions.publish(edits);
2452        }
2453        cx.emit(Event::Edited {
2454            edited_buffer: None,
2455        });
2456    }
2457
2458    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2459        self.buffers.values().map(|state| state.buffer.clone())
2460    }
2461
2462    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2463        self.all_buffers_iter().collect()
2464    }
2465
2466    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2467        self.buffers.keys().copied()
2468    }
2469
2470    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2471        self.all_buffer_ids_iter().collect()
2472    }
2473
2474    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2475        self.buffers
2476            .get(&buffer_id)
2477            .map(|state| state.buffer.clone())
2478    }
2479
2480    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2481        self.point_to_buffer_offset(point, cx)
2482            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2483    }
2484
2485    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2486        let buffer_id = self
2487            .snapshot
2488            .borrow()
2489            .excerpts
2490            .first()
2491            .map(|excerpt| excerpt.buffer.remote_id());
2492        buffer_id
2493            .and_then(|buffer_id| self.buffer(buffer_id))
2494            .map(|buffer| {
2495                let buffer = buffer.read(cx);
2496                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2497            })
2498            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2499    }
2500
2501    pub fn language_settings_at<'a, T: ToOffset>(
2502        &'a self,
2503        point: T,
2504        cx: &'a App,
2505    ) -> Cow<'a, LanguageSettings> {
2506        let mut language = None;
2507        let mut file = None;
2508        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2509            let buffer = buffer.read(cx);
2510            language = buffer.language_at(offset);
2511            file = buffer.file();
2512        }
2513        language_settings(language.map(|l| l.name()), file, cx)
2514    }
2515
2516    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2517        self.buffers.values().for_each(|state| f(&state.buffer))
2518    }
2519
2520    pub fn explicit_title(&self) -> Option<&str> {
2521        self.title.as_deref()
2522    }
2523
2524    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2525        if let Some(title) = self.title.as_ref() {
2526            return title.into();
2527        }
2528
2529        if let Some(buffer) = self.as_singleton() {
2530            let buffer = buffer.read(cx);
2531
2532            if let Some(file) = buffer.file() {
2533                return file.file_name(cx).into();
2534            }
2535
2536            if let Some(title) = self.buffer_content_title(buffer) {
2537                return title;
2538            }
2539        };
2540
2541        "untitled".into()
2542    }
2543
2544    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2545        let mut is_leading_whitespace = true;
2546        let mut count = 0;
2547        let mut prev_was_space = false;
2548        let mut title = String::new();
2549
2550        for ch in buffer.snapshot().chars() {
2551            if is_leading_whitespace && ch.is_whitespace() {
2552                continue;
2553            }
2554
2555            is_leading_whitespace = false;
2556
2557            if ch == '\n' || count >= 40 {
2558                break;
2559            }
2560
2561            if ch.is_whitespace() {
2562                if !prev_was_space {
2563                    title.push(' ');
2564                    count += 1;
2565                    prev_was_space = true;
2566                }
2567            } else {
2568                title.push(ch);
2569                count += 1;
2570                prev_was_space = false;
2571            }
2572        }
2573
2574        let title = title.trim_end().to_string();
2575
2576        if title.is_empty() {
2577            return None;
2578        }
2579
2580        Some(title.into())
2581    }
2582
2583    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2584        self.title = Some(title);
2585        cx.notify();
2586    }
2587
2588    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2589    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2590        for buffer_state in self.buffers.values() {
2591            buffer_state
2592                .buffer
2593                .update(cx, |buffer, _cx| buffer.refresh_preview());
2594        }
2595    }
2596
2597    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2598    pub fn preserve_preview(&self, cx: &App) -> bool {
2599        self.buffers
2600            .values()
2601            .all(|state| state.buffer.read(cx).preserve_preview())
2602    }
2603
2604    #[cfg(any(test, feature = "test-support"))]
2605    pub fn is_parsing(&self, cx: &App) -> bool {
2606        self.as_singleton().unwrap().read(cx).is_parsing()
2607    }
2608
2609    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2610        let buffer_id = diff.read(cx).buffer_id;
2611
2612        if let Some(existing_diff) = self.diff_for(buffer_id)
2613            && diff.entity_id() == existing_diff.entity_id()
2614        {
2615            return;
2616        }
2617
2618        self.buffer_diff_changed(
2619            diff.clone(),
2620            text::Anchor::min_max_range_for_buffer(buffer_id),
2621            cx,
2622        );
2623        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2624    }
2625
2626    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2627        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2628        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2629        self.snapshot.get_mut().has_inverted_diff = true;
2630        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2631        self.diffs
2632            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2633    }
2634
2635    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2636        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2637    }
2638
2639    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2640        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2641    }
2642
2643    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2644        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2645    }
2646
2647    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2648        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2649        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2650    }
2651
2652    pub fn all_diff_hunks_expanded(&self) -> bool {
2653        self.snapshot.borrow().all_diff_hunks_expanded
2654    }
2655
2656    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2657        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2658        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2659    }
2660
2661    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2662        self.snapshot.get_mut().show_deleted_hunks = show;
2663        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2664    }
2665
2666    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2667        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2668    }
2669
2670    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2671        self.read(cx)
2672            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2673            .nth(1)
2674            .is_some()
2675    }
2676
2677    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2678        let snapshot = self.read(cx);
2679        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2680        let offset_range = range.to_offset(&snapshot);
2681        cursor.seek(&offset_range.start, Bias::Left);
2682        while let Some(item) = cursor.item() {
2683            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2684                break;
2685            }
2686            if item.hunk_info().is_some() {
2687                return true;
2688            }
2689            cursor.next();
2690        }
2691        false
2692    }
2693
2694    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2695        let snapshot = self.read(cx);
2696        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2697        for range in ranges {
2698            let range = range.to_point(&snapshot);
2699            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2700            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2701                .min(snapshot.len());
2702            cursor.seek(&start, Bias::Right);
2703            while let Some(item) = cursor.item() {
2704                if *cursor.start() >= end {
2705                    break;
2706                }
2707                if item.hunk_info().is_some() {
2708                    return true;
2709                }
2710                cursor.next();
2711            }
2712        }
2713        false
2714    }
2715
2716    pub fn expand_or_collapse_diff_hunks_inner(
2717        &mut self,
2718        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2719        expand: bool,
2720        cx: &mut Context<Self>,
2721    ) {
2722        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2723            return;
2724        }
2725        self.sync_mut(cx);
2726        let mut snapshot = self.snapshot.get_mut();
2727        let mut excerpt_edits = Vec::new();
2728        let mut last_hunk_row = None;
2729        for (range, end_excerpt_id) in ranges {
2730            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2731                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2732                    continue;
2733                }
2734                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2735                    continue;
2736                }
2737                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2738                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2739                let start = snapshot.excerpt_offset_for_anchor(&start);
2740                let end = snapshot.excerpt_offset_for_anchor(&end);
2741                last_hunk_row = Some(diff_hunk.row_range.start);
2742                excerpt_edits.push(text::Edit {
2743                    old: start..end,
2744                    new: start..end,
2745                });
2746            }
2747        }
2748
2749        let edits = Self::sync_diff_transforms(
2750            &mut snapshot,
2751            excerpt_edits,
2752            DiffChangeKind::ExpandOrCollapseHunks { expand },
2753        );
2754        if !edits.is_empty() {
2755            self.subscriptions.publish(edits);
2756        }
2757        cx.emit(Event::DiffHunksToggled);
2758        cx.emit(Event::Edited {
2759            edited_buffer: None,
2760        });
2761    }
2762
2763    pub fn expand_or_collapse_diff_hunks(
2764        &mut self,
2765        ranges: Vec<Range<Anchor>>,
2766        expand: bool,
2767        cx: &mut Context<Self>,
2768    ) {
2769        let snapshot = self.snapshot.borrow().clone();
2770        let ranges = ranges.iter().map(move |range| {
2771            let end_excerpt_id = range.end.excerpt_id;
2772            let range = range.to_point(&snapshot);
2773            let mut peek_end = range.end;
2774            if range.end.row < snapshot.max_row().0 {
2775                peek_end = Point::new(range.end.row + 1, 0);
2776            };
2777            (range.start..peek_end, end_excerpt_id)
2778        });
2779        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2780    }
2781
2782    pub fn resize_excerpt(
2783        &mut self,
2784        id: ExcerptId,
2785        range: Range<text::Anchor>,
2786        cx: &mut Context<Self>,
2787    ) {
2788        self.sync_mut(cx);
2789
2790        let mut snapshot = self.snapshot.get_mut();
2791        let locator = snapshot.excerpt_locator_for_id(id);
2792        let mut new_excerpts = SumTree::default();
2793        let mut cursor = snapshot
2794            .excerpts
2795            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2796        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2797
2798        let prefix = cursor.slice(&Some(locator), Bias::Left);
2799        new_excerpts.append(prefix, ());
2800
2801        let mut excerpt = cursor.item().unwrap().clone();
2802        let old_text_len = excerpt.text_summary.len;
2803
2804        excerpt.range.context.start = range.start;
2805        excerpt.range.context.end = range.end;
2806        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2807
2808        excerpt.text_summary = excerpt
2809            .buffer
2810            .text_summary_for_range(excerpt.range.context.clone());
2811
2812        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2813        let old_start_offset = cursor.start().1;
2814        let new_text_len = excerpt.text_summary.len;
2815        let edit = Edit {
2816            old: old_start_offset..old_start_offset + old_text_len,
2817            new: new_start_offset..new_start_offset + new_text_len,
2818        };
2819
2820        if let Some(last_edit) = edits.last_mut() {
2821            if last_edit.old.end == edit.old.start {
2822                last_edit.old.end = edit.old.end;
2823                last_edit.new.end = edit.new.end;
2824            } else {
2825                edits.push(edit);
2826            }
2827        } else {
2828            edits.push(edit);
2829        }
2830
2831        new_excerpts.push(excerpt, ());
2832
2833        cursor.next();
2834
2835        new_excerpts.append(cursor.suffix(), ());
2836
2837        drop(cursor);
2838        snapshot.excerpts = new_excerpts;
2839
2840        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2841        if !edits.is_empty() {
2842            self.subscriptions.publish(edits);
2843        }
2844        cx.emit(Event::Edited {
2845            edited_buffer: None,
2846        });
2847        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2848        cx.notify();
2849    }
2850
2851    pub fn expand_excerpts(
2852        &mut self,
2853        ids: impl IntoIterator<Item = ExcerptId>,
2854        line_count: u32,
2855        direction: ExpandExcerptDirection,
2856        cx: &mut Context<Self>,
2857    ) {
2858        if line_count == 0 {
2859            return;
2860        }
2861        self.sync_mut(cx);
2862        if !self.excerpts_by_path.is_empty() {
2863            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2864            return;
2865        }
2866        let mut snapshot = self.snapshot.get_mut();
2867
2868        let ids = ids.into_iter().collect::<Vec<_>>();
2869        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2870        let mut new_excerpts = SumTree::default();
2871        let mut cursor = snapshot
2872            .excerpts
2873            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2874        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2875
2876        for locator in &locators {
2877            let prefix = cursor.slice(&Some(locator), Bias::Left);
2878            new_excerpts.append(prefix, ());
2879
2880            let mut excerpt = cursor.item().unwrap().clone();
2881            let old_text_len = excerpt.text_summary.len;
2882
2883            let up_line_count = if direction.should_expand_up() {
2884                line_count
2885            } else {
2886                0
2887            };
2888
2889            let start_row = excerpt
2890                .range
2891                .context
2892                .start
2893                .to_point(&excerpt.buffer)
2894                .row
2895                .saturating_sub(up_line_count);
2896            let start_point = Point::new(start_row, 0);
2897            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2898
2899            let down_line_count = if direction.should_expand_down() {
2900                line_count
2901            } else {
2902                0
2903            };
2904
2905            let mut end_point = excerpt.buffer.clip_point(
2906                excerpt.range.context.end.to_point(&excerpt.buffer)
2907                    + Point::new(down_line_count, 0),
2908                Bias::Left,
2909            );
2910            end_point.column = excerpt.buffer.line_len(end_point.row);
2911            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2912            excerpt.max_buffer_row = end_point.row;
2913
2914            excerpt.text_summary = excerpt
2915                .buffer
2916                .text_summary_for_range(excerpt.range.context.clone());
2917
2918            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2919            let old_start_offset = cursor.start().1;
2920            let new_text_len = excerpt.text_summary.len;
2921            let edit = Edit {
2922                old: old_start_offset..old_start_offset + old_text_len,
2923                new: new_start_offset..new_start_offset + new_text_len,
2924            };
2925
2926            if let Some(last_edit) = edits.last_mut() {
2927                if last_edit.old.end == edit.old.start {
2928                    last_edit.old.end = edit.old.end;
2929                    last_edit.new.end = edit.new.end;
2930                } else {
2931                    edits.push(edit);
2932                }
2933            } else {
2934                edits.push(edit);
2935            }
2936
2937            new_excerpts.push(excerpt, ());
2938
2939            cursor.next();
2940        }
2941
2942        new_excerpts.append(cursor.suffix(), ());
2943
2944        drop(cursor);
2945        snapshot.excerpts = new_excerpts;
2946
2947        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2948        if !edits.is_empty() {
2949            self.subscriptions.publish(edits);
2950        }
2951        cx.emit(Event::Edited {
2952            edited_buffer: None,
2953        });
2954        cx.emit(Event::ExcerptsExpanded { ids });
2955        cx.notify();
2956    }
2957
2958    #[ztracing::instrument(skip_all)]
2959    fn sync(&self, cx: &App) {
2960        let changed = self.buffer_changed_since_sync.replace(false);
2961        if !changed {
2962            return;
2963        }
2964        let edits = Self::sync_from_buffer_changes(
2965            &mut self.snapshot.borrow_mut(),
2966            &self.buffers,
2967            &self.diffs,
2968            cx,
2969        );
2970        if !edits.is_empty() {
2971            self.subscriptions.publish(edits);
2972        }
2973    }
2974
2975    fn sync_mut(&mut self, cx: &App) {
2976        let changed = self.buffer_changed_since_sync.replace(false);
2977        if !changed {
2978            return;
2979        }
2980        let edits =
2981            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2982
2983        if !edits.is_empty() {
2984            self.subscriptions.publish(edits);
2985        }
2986    }
2987
2988    fn sync_from_buffer_changes(
2989        snapshot: &mut MultiBufferSnapshot,
2990        buffers: &BTreeMap<BufferId, BufferState>,
2991        diffs: &HashMap<BufferId, DiffState>,
2992        cx: &App,
2993    ) -> Vec<Edit<MultiBufferOffset>> {
2994        let MultiBufferSnapshot {
2995            excerpts,
2996            diffs: buffer_diff,
2997            diff_transforms: _,
2998            non_text_state_update_count,
2999            edit_count,
3000            is_dirty,
3001            has_deleted_file,
3002            has_conflict,
3003            has_inverted_diff: _,
3004            singleton: _,
3005            excerpt_ids: _,
3006            replaced_excerpts: _,
3007            trailing_excerpt_update_count: _,
3008            all_diff_hunks_expanded: _,
3009            show_deleted_hunks: _,
3010            use_extended_diff_range: _,
3011            show_headers: _,
3012        } = snapshot;
3013        *is_dirty = false;
3014        *has_deleted_file = false;
3015        *has_conflict = false;
3016
3017        if !diffs.is_empty() {
3018            let mut diffs_to_add = Vec::new();
3019            for (id, diff) in diffs {
3020                if diff.is_inverted || buffer_diff.get(id).is_none() {
3021                    if diffs_to_add.capacity() == 0 {
3022                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3023                        // meaning re-allocations will be fairly expensive
3024                        diffs_to_add.reserve(diffs.len());
3025                    }
3026                    diffs_to_add.push((*id, diff.snapshot(cx)));
3027                }
3028            }
3029            buffer_diff.extend(diffs_to_add);
3030        }
3031
3032        let mut excerpts_to_edit = Vec::new();
3033        let mut non_text_state_updated = false;
3034        let mut edited = false;
3035        for buffer_state in buffers.values() {
3036            let buffer = buffer_state.buffer.read(cx);
3037            let version = buffer.version();
3038            let non_text_state_update_count = buffer.non_text_state_update_count();
3039
3040            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3041            let buffer_non_text_state_updated =
3042                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3043            if buffer_edited || buffer_non_text_state_updated {
3044                *buffer_state.last_version.borrow_mut() = version;
3045                buffer_state
3046                    .last_non_text_state_update_count
3047                    .set(non_text_state_update_count);
3048                excerpts_to_edit.extend(
3049                    buffer_state
3050                        .excerpts
3051                        .iter()
3052                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3053                );
3054            }
3055
3056            edited |= buffer_edited;
3057            non_text_state_updated |= buffer_non_text_state_updated;
3058            *is_dirty |= buffer.is_dirty();
3059            *has_deleted_file |= buffer
3060                .file()
3061                .is_some_and(|file| file.disk_state().is_deleted());
3062            *has_conflict |= buffer.has_conflict();
3063        }
3064        if edited {
3065            *edit_count += 1;
3066        }
3067        if non_text_state_updated {
3068            *non_text_state_update_count += 1;
3069        }
3070
3071        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3072
3073        let mut edits = Vec::new();
3074        let mut new_excerpts = SumTree::default();
3075        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3076
3077        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3078            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3079            let old_excerpt = cursor.item().unwrap();
3080            let buffer = buffer.read(cx);
3081            let buffer_id = buffer.remote_id();
3082            let mut new_excerpt;
3083            if buffer_edited {
3084                edits.extend(
3085                    buffer
3086                        .edits_since_in_range::<usize>(
3087                            old_excerpt.buffer.version(),
3088                            old_excerpt.range.context.clone(),
3089                        )
3090                        .map(|edit| {
3091                            let excerpt_old_start = cursor.start().1;
3092                            let excerpt_new_start =
3093                                ExcerptDimension(new_excerpts.summary().text.len);
3094                            let old_start = excerpt_old_start + edit.old.start;
3095                            let old_end = excerpt_old_start + edit.old.end;
3096                            let new_start = excerpt_new_start + edit.new.start;
3097                            let new_end = excerpt_new_start + edit.new.end;
3098                            Edit {
3099                                old: old_start..old_end,
3100                                new: new_start..new_end,
3101                            }
3102                        }),
3103                );
3104
3105                new_excerpt = Excerpt::new(
3106                    old_excerpt.id,
3107                    locator.clone(),
3108                    buffer_id,
3109                    Arc::new(buffer.snapshot()),
3110                    old_excerpt.range.clone(),
3111                    old_excerpt.has_trailing_newline,
3112                );
3113            } else {
3114                new_excerpt = old_excerpt.clone();
3115                new_excerpt.buffer = Arc::new(buffer.snapshot());
3116            }
3117
3118            new_excerpts.push(new_excerpt, ());
3119            cursor.next();
3120        }
3121        new_excerpts.append(cursor.suffix(), ());
3122
3123        drop(cursor);
3124        *excerpts = new_excerpts;
3125
3126        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3127    }
3128
3129    fn sync_diff_transforms(
3130        snapshot: &mut MultiBufferSnapshot,
3131        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3132        change_kind: DiffChangeKind,
3133    ) -> Vec<Edit<MultiBufferOffset>> {
3134        if excerpt_edits.is_empty() {
3135            return vec![];
3136        }
3137
3138        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3139        let mut old_diff_transforms = snapshot
3140            .diff_transforms
3141            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3142        let mut new_diff_transforms = SumTree::default();
3143        let mut old_expanded_hunks = HashSet::default();
3144        let mut output_edits = Vec::new();
3145        let mut output_delta = 0_isize;
3146        let mut at_transform_boundary = true;
3147        let mut end_of_current_insert = None;
3148
3149        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3150        while let Some(edit) = excerpt_edits.next() {
3151            excerpts.seek_forward(&edit.new.start, Bias::Right);
3152            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3153                excerpts.prev();
3154            }
3155
3156            // Keep any transforms that are before the edit.
3157            if at_transform_boundary {
3158                at_transform_boundary = false;
3159                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3160                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3161                if let Some(transform) = old_diff_transforms.item()
3162                    && old_diff_transforms.end().0 == edit.old.start
3163                    && old_diff_transforms.start().0 < edit.old.start
3164                {
3165                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3166                    old_diff_transforms.next();
3167                }
3168            }
3169
3170            // Compute the start of the edit in output coordinates.
3171            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3172            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3173            let edit_new_start =
3174                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3175
3176            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3177                &edit,
3178                &mut excerpts,
3179                &mut old_diff_transforms,
3180                &mut new_diff_transforms,
3181                &mut end_of_current_insert,
3182                &mut old_expanded_hunks,
3183                snapshot,
3184                change_kind,
3185            );
3186
3187            // Compute the end of the edit in output coordinates.
3188            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3189            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3190            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3191            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3192            let output_edit = Edit {
3193                old: edit_old_start..edit_old_end,
3194                new: edit_new_start..edit_new_end,
3195            };
3196
3197            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3198            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3199            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3200                output_edits.push(output_edit);
3201            }
3202
3203            // If this is the last edit that intersects the current diff transform,
3204            // then recreate the content up to the end of this transform, to prepare
3205            // for reusing additional slices of the old transforms.
3206            if excerpt_edits
3207                .peek()
3208                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3209            {
3210                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3211                    && match old_diff_transforms.item() {
3212                        Some(DiffTransform::BufferContent {
3213                            inserted_hunk_info: Some(hunk),
3214                            ..
3215                        }) => excerpts.item().is_some_and(|excerpt| {
3216                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3217                                && diff.is_inverted
3218                            {
3219                                return true;
3220                            }
3221                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3222                        }),
3223                        _ => true,
3224                    };
3225
3226                let mut excerpt_offset = edit.new.end;
3227                if !keep_next_old_transform {
3228                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3229                    old_diff_transforms.next();
3230                }
3231
3232                old_expanded_hunks.clear();
3233                Self::push_buffer_content_transform(
3234                    snapshot,
3235                    &mut new_diff_transforms,
3236                    excerpt_offset,
3237                    end_of_current_insert,
3238                );
3239                at_transform_boundary = true;
3240            }
3241        }
3242
3243        // Keep any transforms that are after the last edit.
3244        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3245
3246        // Ensure there's always at least one buffer content transform.
3247        if new_diff_transforms.is_empty() {
3248            new_diff_transforms.push(
3249                DiffTransform::BufferContent {
3250                    summary: Default::default(),
3251                    inserted_hunk_info: None,
3252                },
3253                (),
3254            );
3255        }
3256
3257        drop(old_diff_transforms);
3258        drop(excerpts);
3259        snapshot.diff_transforms = new_diff_transforms;
3260        snapshot.edit_count += 1;
3261
3262        #[cfg(any(test, feature = "test-support"))]
3263        snapshot.check_invariants();
3264        output_edits
3265    }
3266
3267    fn recompute_diff_transforms_for_edit(
3268        edit: &Edit<ExcerptOffset>,
3269        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3270        old_diff_transforms: &mut Cursor<
3271            DiffTransform,
3272            Dimensions<ExcerptOffset, MultiBufferOffset>,
3273        >,
3274        new_diff_transforms: &mut SumTree<DiffTransform>,
3275        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3276        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3277        snapshot: &MultiBufferSnapshot,
3278        change_kind: DiffChangeKind,
3279    ) -> bool {
3280        log::trace!(
3281            "recomputing diff transform for edit {:?} => {:?}",
3282            edit.old.start..edit.old.end,
3283            edit.new.start..edit.new.end
3284        );
3285
3286        // Record which hunks were previously expanded.
3287        while let Some(item) = old_diff_transforms.item() {
3288            if let Some(hunk_info) = item.hunk_info() {
3289                log::trace!(
3290                    "previously expanded hunk at {:?}",
3291                    old_diff_transforms.start()
3292                );
3293                old_expanded_hunks.insert(hunk_info);
3294            }
3295            if old_diff_transforms.end().0 > edit.old.end {
3296                break;
3297            }
3298            old_diff_transforms.next();
3299        }
3300
3301        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3302        // For inverted diffs, hunks are always shown, so we can't skip this.
3303        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3304        if old_expanded_hunks.is_empty()
3305            && change_kind == DiffChangeKind::BufferEdited
3306            && !all_diff_hunks_expanded
3307            && !snapshot.has_inverted_diff
3308        {
3309            return false;
3310        }
3311
3312        // Visit each excerpt that intersects the edit.
3313        let mut did_expand_hunks = false;
3314        while let Some(excerpt) = excerpts.item() {
3315            // Recompute the expanded hunks in the portion of the excerpt that
3316            // intersects the edit.
3317            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3318                let buffer = &excerpt.buffer;
3319                let excerpt_start = *excerpts.start();
3320                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3321                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3322                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3323                let edit_buffer_start =
3324                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3325                let edit_buffer_end =
3326                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3327                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3328
3329                if diff.is_inverted {
3330                    for hunk in diff.hunks_intersecting_base_text_range(
3331                        edit_buffer_start..edit_buffer_end,
3332                        diff.original_buffer_snapshot(),
3333                    ) {
3334                        did_expand_hunks = true;
3335                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3336                        if hunk_buffer_range.start < excerpt_buffer_start {
3337                            log::trace!("skipping hunk that starts before excerpt");
3338                            continue;
3339                        }
3340                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3341                        let hunk_excerpt_start = excerpt_start
3342                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3343                        let hunk_excerpt_end = excerpt_end
3344                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3345                        Self::push_buffer_content_transform(
3346                            snapshot,
3347                            new_diff_transforms,
3348                            hunk_excerpt_start,
3349                            *end_of_current_insert,
3350                        );
3351                        if !hunk_buffer_range.is_empty() {
3352                            let hunk_info = DiffTransformHunkInfo {
3353                                excerpt_id: excerpt.id,
3354                                hunk_start_anchor: hunk.buffer_range.start,
3355                                hunk_secondary_status: hunk.secondary_status,
3356                                is_logically_deleted: true,
3357                            };
3358                            *end_of_current_insert =
3359                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3360                        }
3361                    }
3362                } else {
3363                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3364                        ..buffer.anchor_after(edit_buffer_end);
3365                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3366                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3367                            continue;
3368                        }
3369
3370                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3371                        if hunk_buffer_range.start < excerpt_buffer_start {
3372                            log::trace!("skipping hunk that starts before excerpt");
3373                            continue;
3374                        }
3375
3376                        let hunk_info = DiffTransformHunkInfo {
3377                            excerpt_id: excerpt.id,
3378                            hunk_start_anchor: hunk.buffer_range.start,
3379                            hunk_secondary_status: hunk.secondary_status,
3380                            is_logically_deleted: false,
3381                        };
3382
3383                        let hunk_excerpt_start = excerpt_start
3384                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3385                        let hunk_excerpt_end = excerpt_end
3386                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3387
3388                        Self::push_buffer_content_transform(
3389                            snapshot,
3390                            new_diff_transforms,
3391                            hunk_excerpt_start,
3392                            *end_of_current_insert,
3393                        );
3394
3395                        // For every existing hunk, determine if it was previously expanded
3396                        // and if it should currently be expanded.
3397                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3398                        let should_expand_hunk = match &change_kind {
3399                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3400                                was_previously_expanded || all_diff_hunks_expanded
3401                            }
3402                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3403                                let intersects = hunk_buffer_range.is_empty()
3404                                    || hunk_buffer_range.end > edit_buffer_start;
3405                                if *expand {
3406                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3407                                } else {
3408                                    !intersects
3409                                        && (was_previously_expanded || all_diff_hunks_expanded)
3410                                }
3411                            }
3412                            _ => was_previously_expanded || all_diff_hunks_expanded,
3413                        };
3414
3415                        if should_expand_hunk {
3416                            did_expand_hunks = true;
3417                            log::trace!(
3418                                "expanding hunk {:?}, excerpt:{:?}",
3419                                hunk_excerpt_start..hunk_excerpt_end,
3420                                excerpt.id
3421                            );
3422
3423                            if !hunk.diff_base_byte_range.is_empty()
3424                                && hunk_buffer_range.start >= edit_buffer_start
3425                                && hunk_buffer_range.start <= excerpt_buffer_end
3426                                && snapshot.show_deleted_hunks
3427                            {
3428                                let base_text = diff.base_text();
3429                                let mut text_cursor =
3430                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3431                                let mut base_text_summary = text_cursor
3432                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3433
3434                                let mut has_trailing_newline = false;
3435                                if base_text_summary.last_line_chars > 0 {
3436                                    base_text_summary += TextSummary::newline();
3437                                    has_trailing_newline = true;
3438                                }
3439
3440                                new_diff_transforms.push(
3441                                    DiffTransform::DeletedHunk {
3442                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3443                                        summary: base_text_summary,
3444                                        buffer_id: excerpt.buffer_id,
3445                                        hunk_info,
3446                                        has_trailing_newline,
3447                                    },
3448                                    (),
3449                                );
3450                            }
3451
3452                            if !hunk_buffer_range.is_empty() {
3453                                *end_of_current_insert =
3454                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3455                            }
3456                        }
3457                    }
3458                }
3459            }
3460
3461            if excerpts.end() <= edit.new.end {
3462                excerpts.next();
3463            } else {
3464                break;
3465            }
3466        }
3467
3468        did_expand_hunks || !old_expanded_hunks.is_empty()
3469    }
3470
3471    fn append_diff_transforms(
3472        new_transforms: &mut SumTree<DiffTransform>,
3473        subtree: SumTree<DiffTransform>,
3474    ) {
3475        if let Some(DiffTransform::BufferContent {
3476            inserted_hunk_info,
3477            summary,
3478        }) = subtree.first()
3479            && Self::extend_last_buffer_content_transform(
3480                new_transforms,
3481                *inserted_hunk_info,
3482                *summary,
3483            )
3484        {
3485            let mut cursor = subtree.cursor::<()>(());
3486            cursor.next();
3487            cursor.next();
3488            new_transforms.append(cursor.suffix(), ());
3489            return;
3490        }
3491        new_transforms.append(subtree, ());
3492    }
3493
3494    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3495        if let DiffTransform::BufferContent {
3496            inserted_hunk_info: inserted_hunk_anchor,
3497            summary,
3498        } = transform
3499            && Self::extend_last_buffer_content_transform(
3500                new_transforms,
3501                inserted_hunk_anchor,
3502                summary,
3503            )
3504        {
3505            return;
3506        }
3507        new_transforms.push(transform, ());
3508    }
3509
3510    fn push_buffer_content_transform(
3511        old_snapshot: &MultiBufferSnapshot,
3512        new_transforms: &mut SumTree<DiffTransform>,
3513        end_offset: ExcerptOffset,
3514        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3515    ) {
3516        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3517            (end_offset.min(insertion_end_offset), Some(hunk_info))
3518        });
3519        let unchanged_region = [(end_offset, None)];
3520
3521        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3522        {
3523            let start_offset = new_transforms.summary().excerpt_len();
3524            if end_offset <= start_offset {
3525                continue;
3526            }
3527            let summary_to_add = old_snapshot
3528                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3529
3530            if !Self::extend_last_buffer_content_transform(
3531                new_transforms,
3532                inserted_hunk_info,
3533                summary_to_add,
3534            ) {
3535                new_transforms.push(
3536                    DiffTransform::BufferContent {
3537                        summary: summary_to_add,
3538                        inserted_hunk_info,
3539                    },
3540                    (),
3541                )
3542            }
3543        }
3544    }
3545
3546    fn extend_last_buffer_content_transform(
3547        new_transforms: &mut SumTree<DiffTransform>,
3548        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3549        summary_to_add: MBTextSummary,
3550    ) -> bool {
3551        let mut did_extend = false;
3552        new_transforms.update_last(
3553            |last_transform| {
3554                if let DiffTransform::BufferContent {
3555                    summary,
3556                    inserted_hunk_info: inserted_hunk_anchor,
3557                } = last_transform
3558                    && *inserted_hunk_anchor == new_inserted_hunk_info
3559                {
3560                    *summary += summary_to_add;
3561                    did_extend = true;
3562                }
3563            },
3564            (),
3565        );
3566        did_extend
3567    }
3568}
3569
3570fn build_excerpt_ranges(
3571    ranges: impl IntoIterator<Item = Range<Point>>,
3572    context_line_count: u32,
3573    buffer_snapshot: &BufferSnapshot,
3574) -> Vec<ExcerptRange<Point>> {
3575    ranges
3576        .into_iter()
3577        .map(|range| {
3578            let start_row = range.start.row.saturating_sub(context_line_count);
3579            let start = Point::new(start_row, 0);
3580            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3581            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3582            ExcerptRange {
3583                context: start..end,
3584                primary: range,
3585            }
3586        })
3587        .collect()
3588}
3589
3590#[cfg(any(test, feature = "test-support"))]
3591impl MultiBuffer {
3592    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3593        let buffer = cx.new(|cx| Buffer::local(text, cx));
3594        cx.new(|cx| Self::singleton(buffer, cx))
3595    }
3596
3597    pub fn build_multi<const COUNT: usize>(
3598        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3599        cx: &mut gpui::App,
3600    ) -> Entity<Self> {
3601        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3602        for (text, ranges) in excerpts {
3603            let buffer = cx.new(|cx| Buffer::local(text, cx));
3604            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3605            multi.update(cx, |multi, cx| {
3606                multi.push_excerpts(buffer, excerpt_ranges, cx)
3607            });
3608        }
3609
3610        multi
3611    }
3612
3613    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3614        cx.new(|cx| Self::singleton(buffer, cx))
3615    }
3616
3617    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3618        cx.new(|cx| {
3619            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3620            let mutation_count = rng.random_range(1..=5);
3621            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3622            multibuffer
3623        })
3624    }
3625
3626    pub fn randomly_edit(
3627        &mut self,
3628        rng: &mut impl rand::Rng,
3629        edit_count: usize,
3630        cx: &mut Context<Self>,
3631    ) {
3632        use util::RandomCharIter;
3633
3634        let snapshot = self.read(cx);
3635        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3636        let mut last_end = None;
3637        for _ in 0..edit_count {
3638            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3639                break;
3640            }
3641
3642            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3643            let end =
3644                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3645            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3646            last_end = Some(end);
3647
3648            let mut range = start..end;
3649            if rng.random_bool(0.2) {
3650                mem::swap(&mut range.start, &mut range.end);
3651            }
3652
3653            let new_text_len = rng.random_range(0..10);
3654            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3655
3656            edits.push((range, new_text.into()));
3657        }
3658        log::info!("mutating multi-buffer with {:?}", edits);
3659        drop(snapshot);
3660
3661        self.edit(edits, None, cx);
3662    }
3663
3664    pub fn randomly_edit_excerpts(
3665        &mut self,
3666        rng: &mut impl rand::Rng,
3667        mutation_count: usize,
3668        cx: &mut Context<Self>,
3669    ) {
3670        use rand::prelude::*;
3671        use std::env;
3672        use util::RandomCharIter;
3673
3674        let max_excerpts = env::var("MAX_EXCERPTS")
3675            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3676            .unwrap_or(5);
3677
3678        let mut buffers = Vec::new();
3679        for _ in 0..mutation_count {
3680            if rng.random_bool(0.05) {
3681                log::info!("Clearing multi-buffer");
3682                self.clear(cx);
3683                continue;
3684            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3685                let ids = self.excerpt_ids();
3686                let mut excerpts = HashSet::default();
3687                for _ in 0..rng.random_range(0..ids.len()) {
3688                    excerpts.extend(ids.choose(rng).copied());
3689                }
3690
3691                let line_count = rng.random_range(0..5);
3692
3693                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3694
3695                self.expand_excerpts(
3696                    excerpts.iter().cloned(),
3697                    line_count,
3698                    ExpandExcerptDirection::UpAndDown,
3699                    cx,
3700                );
3701                continue;
3702            }
3703
3704            let excerpt_ids = self.excerpt_ids();
3705            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3706                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3707                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3708                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3709                    let buffer = buffers.last().unwrap().read(cx);
3710                    log::info!(
3711                        "Creating new buffer {} with text: {:?}",
3712                        buffer.remote_id(),
3713                        buffer.text()
3714                    );
3715                    buffers.last().unwrap().clone()
3716                } else {
3717                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3718                };
3719
3720                let buffer = buffer_handle.read(cx);
3721                let buffer_text = buffer.text();
3722                let ranges = (0..rng.random_range(0..5))
3723                    .map(|_| {
3724                        let end_ix =
3725                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3726                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3727                        ExcerptRange::new(start_ix..end_ix)
3728                    })
3729                    .collect::<Vec<_>>();
3730                log::info!(
3731                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3732                    buffer_handle.read(cx).remote_id(),
3733                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3734                    ranges
3735                        .iter()
3736                        .map(|r| &buffer_text[r.context.clone()])
3737                        .collect::<Vec<_>>()
3738                );
3739
3740                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3741                log::info!("Inserted with ids: {:?}", excerpt_id);
3742            } else {
3743                let remove_count = rng.random_range(1..=excerpt_ids.len());
3744                let mut excerpts_to_remove = excerpt_ids
3745                    .choose_multiple(rng, remove_count)
3746                    .cloned()
3747                    .collect::<Vec<_>>();
3748                let snapshot = self.snapshot.borrow();
3749                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3750                drop(snapshot);
3751                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3752                self.remove_excerpts(excerpts_to_remove, cx);
3753            }
3754        }
3755    }
3756
3757    pub fn randomly_mutate(
3758        &mut self,
3759        rng: &mut impl rand::Rng,
3760        mutation_count: usize,
3761        cx: &mut Context<Self>,
3762    ) {
3763        use rand::prelude::*;
3764
3765        if rng.random_bool(0.7) || self.singleton {
3766            let buffer = self
3767                .buffers
3768                .values()
3769                .choose(rng)
3770                .map(|state| state.buffer.clone());
3771
3772            if let Some(buffer) = buffer {
3773                buffer.update(cx, |buffer, cx| {
3774                    if rng.random() {
3775                        buffer.randomly_edit(rng, mutation_count, cx);
3776                    } else {
3777                        buffer.randomly_undo_redo(rng, cx);
3778                    }
3779                });
3780            } else {
3781                self.randomly_edit(rng, mutation_count, cx);
3782            }
3783        } else {
3784            self.randomly_edit_excerpts(rng, mutation_count, cx);
3785        }
3786
3787        self.check_invariants(cx);
3788    }
3789
3790    fn check_invariants(&self, cx: &App) {
3791        self.read(cx).check_invariants();
3792    }
3793}
3794
3795impl EventEmitter<Event> for MultiBuffer {}
3796
3797impl MultiBufferSnapshot {
3798    pub fn text(&self) -> String {
3799        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3800            .map(|chunk| chunk.text)
3801            .collect()
3802    }
3803
3804    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3805        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3806            .flat_map(|c| c.chars().rev())
3807    }
3808
3809    fn reversed_chunks_in_range(
3810        &self,
3811        range: Range<MultiBufferOffset>,
3812    ) -> ReversedMultiBufferChunks<'_> {
3813        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3814        cursor.seek(&range.end);
3815        let current_chunks = cursor.region().as_ref().map(|region| {
3816            let start_overshoot = range.start.saturating_sub(region.range.start);
3817            let end_overshoot = range.end - region.range.start;
3818            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3819            let start = region.buffer_range.start + start_overshoot;
3820            region.buffer.reversed_chunks_in_range(start..end)
3821        });
3822        ReversedMultiBufferChunks {
3823            cursor,
3824            current_chunks,
3825            start: range.start,
3826            offset: range.end,
3827        }
3828    }
3829
3830    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3831        let offset = position.to_offset(self);
3832        self.text_for_range(offset..self.len())
3833            .flat_map(|chunk| chunk.chars())
3834    }
3835
3836    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3837        self.chunks(range, false).map(|chunk| chunk.text)
3838    }
3839
3840    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3841        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3842            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3843    }
3844
3845    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3846    where
3847        T: ToOffset,
3848    {
3849        let position = position.to_offset(self);
3850        position == self.clip_offset(position, Bias::Left)
3851            && self
3852                .bytes_in_range(position..self.len())
3853                .flatten()
3854                .copied()
3855                .take(needle.len())
3856                .eq(needle.bytes())
3857    }
3858
3859    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3860        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3861    }
3862
3863    pub fn diff_hunks_in_range<T: ToPoint>(
3864        &self,
3865        range: Range<T>,
3866    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3867        let query_range = range.start.to_point(self)..range.end.to_point(self);
3868        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3869            let diff = self.diffs.get(&buffer.remote_id())?;
3870            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3871                if diff.is_inverted {
3872                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3873                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3874                    Box::new(
3875                        diff.hunks_intersecting_base_text_range(
3876                            buffer_start..buffer_end,
3877                            diff.original_buffer_snapshot(),
3878                        )
3879                        .map(move |hunk| (hunk, buffer, true)),
3880                    )
3881                } else {
3882                    let buffer_start = buffer.anchor_before(buffer_range.start);
3883                    let buffer_end = buffer.anchor_after(buffer_range.end);
3884                    Box::new(
3885                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3886                            .map(move |hunk| (hunk, buffer, false)),
3887                    )
3888                };
3889            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3890                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3891                    return None;
3892                }
3893                let range = if is_inverted {
3894                    hunk.diff_base_byte_range.to_point(&buffer)
3895                } else {
3896                    hunk.range.clone()
3897                };
3898                Some((range, (hunk, is_inverted)))
3899            }))
3900        })
3901        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3902            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3903            {
3904                return None;
3905            }
3906            let end_row = if range.end.column == 0 {
3907                range.end.row
3908            } else {
3909                range.end.row + 1
3910            };
3911
3912            let word_diffs =
3913                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3914                    .then(|| {
3915                        let mut word_diffs = Vec::new();
3916
3917                        if self.show_deleted_hunks || is_inverted {
3918                            let hunk_start_offset = if is_inverted {
3919                                Anchor::in_buffer(
3920                                    excerpt.id,
3921                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3922                                )
3923                                .to_offset(self)
3924                            } else {
3925                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3926                                    .to_offset(self)
3927                            };
3928
3929                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3930                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3931                            }));
3932                        }
3933
3934                        if !is_inverted {
3935                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3936                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3937                            }));
3938                        }
3939                        word_diffs
3940                    })
3941                    .unwrap_or_default();
3942
3943            let buffer_range = if is_inverted {
3944                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3945                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3946            } else {
3947                hunk.buffer_range.clone()
3948            };
3949            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3950                DiffHunkStatusKind::Deleted
3951            } else if hunk.diff_base_byte_range.is_empty() {
3952                DiffHunkStatusKind::Added
3953            } else {
3954                DiffHunkStatusKind::Modified
3955            };
3956            Some(MultiBufferDiffHunk {
3957                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3958                buffer_id: excerpt.buffer_id,
3959                excerpt_id: excerpt.id,
3960                buffer_range,
3961                word_diffs,
3962                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3963                    ..BufferOffset(hunk.diff_base_byte_range.end),
3964                status: DiffHunkStatus {
3965                    kind: status_kind,
3966                    secondary: hunk.secondary_status,
3967                },
3968            })
3969        })
3970    }
3971
3972    fn excerpts_for_range<T: ToOffset>(
3973        &self,
3974        range: Range<T>,
3975    ) -> impl Iterator<Item = &Excerpt> + '_ {
3976        let range = range.start.to_offset(self)..range.end.to_offset(self);
3977        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3978        cursor.seek(&range.start);
3979        std::iter::from_fn(move || {
3980            let region = cursor.region()?;
3981            if region.range.start > range.end
3982                || region.range.start == range.end && region.range.start > range.start
3983            {
3984                return None;
3985            }
3986            let excerpt = region.excerpt;
3987            cursor.next_excerpt_forwards();
3988            Some(excerpt)
3989        })
3990    }
3991
3992    pub fn excerpt_ids_for_range<T: ToOffset>(
3993        &self,
3994        range: Range<T>,
3995    ) -> impl Iterator<Item = ExcerptId> + '_ {
3996        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3997    }
3998
3999    pub fn buffer_ids_for_range<T: ToOffset>(
4000        &self,
4001        range: Range<T>,
4002    ) -> impl Iterator<Item = BufferId> + '_ {
4003        self.excerpts_for_range(range)
4004            .map(|excerpt| excerpt.buffer_id)
4005    }
4006
4007    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4008        &self,
4009        ranges: impl Iterator<Item = Range<T>>,
4010    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4011        ranges.flat_map(|range| {
4012            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4013                .into_iter()
4014        })
4015    }
4016
4017    pub fn range_to_buffer_ranges<R, T>(
4018        &self,
4019        range: R,
4020    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4021    where
4022        R: RangeBounds<T>,
4023        T: ToOffset,
4024    {
4025        let start = match range.start_bound() {
4026            Bound::Included(start) => start.to_offset(self),
4027            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4028            Bound::Unbounded => MultiBufferOffset::ZERO,
4029        };
4030        let end_bound = match range.end_bound() {
4031            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4032            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4033            Bound::Unbounded => Bound::Unbounded,
4034        };
4035        let bounds = (Bound::Included(start), end_bound);
4036
4037        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4038        cursor.seek(&start);
4039
4040        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
4041        while let Some(region) = cursor.region() {
4042            let dominated_by_end_bound = match end_bound {
4043                Bound::Included(end) => region.range.start > end,
4044                Bound::Excluded(end) => region.range.start >= end,
4045                Bound::Unbounded => false,
4046            };
4047            if dominated_by_end_bound {
4048                break;
4049            }
4050            if region.is_main_buffer {
4051                let start_overshoot = start.saturating_sub(region.range.start);
4052                let end_offset = match end_bound {
4053                    Bound::Included(end) | Bound::Excluded(end) => end,
4054                    Bound::Unbounded => region.range.end,
4055                };
4056                let end_overshoot = end_offset.saturating_sub(region.range.start);
4057                let start = region
4058                    .buffer_range
4059                    .end
4060                    .min(region.buffer_range.start + start_overshoot);
4061                let end = region
4062                    .buffer_range
4063                    .end
4064                    .min(region.buffer_range.start + end_overshoot);
4065                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
4066                    *excerpt_id == region.excerpt.id && prev_range.end == start
4067                }) {
4068                    prev.1.end = end;
4069                } else {
4070                    result.push((region.buffer, start..end, region.excerpt.id));
4071                }
4072            }
4073            cursor.next();
4074        }
4075
4076        if let Some(excerpt) = cursor.excerpt() {
4077            let dominated_by_prev_excerpt =
4078                result.last().is_some_and(|(_, _, id)| *id == excerpt.id);
4079            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4080                let excerpt_position = self.len();
4081                if bounds.contains(&excerpt_position) {
4082                    let buffer_offset =
4083                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4084                    result.push((&excerpt.buffer, buffer_offset..buffer_offset, excerpt.id));
4085                }
4086            }
4087        }
4088
4089        result
4090    }
4091
4092    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4093        &self,
4094        range: Range<T>,
4095    ) -> impl Iterator<
4096        Item = (
4097            &BufferSnapshot,
4098            Range<BufferOffset>,
4099            ExcerptId,
4100            Option<Anchor>,
4101        ),
4102    > + '_ {
4103        let start = range.start.to_offset(self);
4104        let end = range.end.to_offset(self);
4105
4106        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4107        cursor.seek(&start);
4108
4109        std::iter::from_fn(move || {
4110            let region = cursor.region()?;
4111            if region.range.start > end {
4112                return None;
4113            }
4114            let start_overshoot = start.saturating_sub(region.range.start);
4115            let end_overshoot = end.saturating_sub(region.range.start);
4116            let start = region
4117                .buffer_range
4118                .end
4119                .min(region.buffer_range.start + start_overshoot);
4120            let end = region
4121                .buffer_range
4122                .end
4123                .min(region.buffer_range.start + end_overshoot);
4124
4125            let region_excerpt_id = region.excerpt.id;
4126            let deleted_hunk_anchor = if region.is_main_buffer {
4127                None
4128            } else {
4129                Some(self.anchor_before(region.range.start))
4130            };
4131            let result = (
4132                region.buffer,
4133                start..end,
4134                region_excerpt_id,
4135                deleted_hunk_anchor,
4136            );
4137            cursor.next();
4138            Some(result)
4139        })
4140    }
4141
4142    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4143    /// coordinates.
4144    ///
4145    /// The given callback will be called for every excerpt intersecting the given range. It will
4146    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4147    /// The callback should return an iterator of metadata items from that buffer, each paired
4148    /// with a buffer range.
4149    ///
4150    /// The returned iterator yields each of these metadata items, paired with its range in
4151    /// multi-buffer coordinates.
4152    fn lift_buffer_metadata<'a, MBD, M, I>(
4153        &'a self,
4154        query_range: Range<MBD>,
4155        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4156    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4157    where
4158        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4159        MBD: MultiBufferDimension
4160            + Ord
4161            + Sub<Output = MBD::TextDimension>
4162            + ops::Add<MBD::TextDimension, Output = MBD>
4163            + ops::AddAssign<MBD::TextDimension>,
4164        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4165            + ops::Add<Output = MBD::TextDimension>
4166            + AddAssign<MBD::TextDimension>
4167            + Ord,
4168    {
4169        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4170        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4171
4172        // Find the excerpt and buffer offset where the given range ends.
4173        cursor.seek(&query_range.end);
4174        let mut range_end = None;
4175        while let Some(region) = cursor.region() {
4176            if region.is_main_buffer {
4177                let mut buffer_end = region.buffer_range.start;
4178                let overshoot = if query_range.end > region.range.start {
4179                    query_range.end - region.range.start
4180                } else {
4181                    <MBD::TextDimension>::default()
4182                };
4183                buffer_end = buffer_end + overshoot;
4184                range_end = Some((region.excerpt.id, buffer_end));
4185                break;
4186            }
4187            cursor.next();
4188        }
4189
4190        cursor.seek(&query_range.start);
4191
4192        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4193            && region.range.start > MBD::default()
4194        {
4195            cursor.prev()
4196        } else if let Some(region) = cursor.region()
4197            && region.is_main_buffer
4198            && region.diff_hunk_status.is_some()
4199        {
4200            cursor.prev();
4201            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4202                cursor.next();
4203            }
4204        }
4205
4206        iter::from_fn(move || {
4207            loop {
4208                let excerpt = cursor.excerpt()?;
4209
4210                // If we have already retrieved metadata for this excerpt, continue to use it.
4211                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4212                    .as_mut()
4213                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4214                {
4215                    Some(metadata)
4216                }
4217                // Otherwise, compute the intersection of the input range with the excerpt's range,
4218                // and retrieve the metadata for the resulting range.
4219                else {
4220                    let region = cursor.region()?;
4221                    let mut buffer_start;
4222                    if region.is_main_buffer {
4223                        buffer_start = region.buffer_range.start;
4224                        if query_range.start > region.range.start {
4225                            let overshoot = query_range.start - region.range.start;
4226                            buffer_start = buffer_start + overshoot;
4227                        }
4228                        buffer_start = buffer_start.min(region.buffer_range.end);
4229                    } else {
4230                        buffer_start = cursor.main_buffer_position()?;
4231                    };
4232                    let mut buffer_end = excerpt
4233                        .range
4234                        .context
4235                        .end
4236                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4237                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4238                        && excerpt.id == end_excerpt_id
4239                    {
4240                        buffer_end = buffer_end.min(end_buffer_offset);
4241                    }
4242
4243                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4244                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4245                    })
4246                };
4247
4248                // Visit each metadata item.
4249                if let Some((metadata_buffer_range, metadata)) =
4250                    metadata_iter.and_then(Iterator::next)
4251                {
4252                    // Find the multibuffer regions that contain the start and end of
4253                    // the metadata item's range.
4254                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4255                        while let Some(region) = cursor.region() {
4256                            if (region.is_main_buffer
4257                                && (region.buffer_range.end >= metadata_buffer_range.start
4258                                    || cursor.is_at_end_of_excerpt()))
4259                                || (!region.is_main_buffer
4260                                    && region.buffer_range.start == metadata_buffer_range.start)
4261                            {
4262                                break;
4263                            }
4264                            cursor.next();
4265                        }
4266                    }
4267                    let start_region = cursor.region()?.clone();
4268                    while let Some(region) = cursor.region() {
4269                        if region.is_main_buffer
4270                            && (region.buffer_range.end > metadata_buffer_range.end
4271                                || cursor.is_at_end_of_excerpt())
4272                        {
4273                            break;
4274                        }
4275                        cursor.next();
4276                    }
4277                    let end_region = cursor.region();
4278
4279                    // Convert the metadata item's range into multibuffer coordinates.
4280                    let mut start_position = start_region.range.start;
4281                    let region_buffer_start = start_region.buffer_range.start;
4282                    if start_region.is_main_buffer
4283                        && metadata_buffer_range.start > region_buffer_start
4284                    {
4285                        start_position =
4286                            start_position + (metadata_buffer_range.start - region_buffer_start);
4287                        start_position = start_position.min(start_region.range.end);
4288                    }
4289
4290                    let mut end_position = self.max_position();
4291                    if let Some(end_region) = &end_region {
4292                        end_position = end_region.range.start;
4293                        debug_assert!(end_region.is_main_buffer);
4294                        let region_buffer_start = end_region.buffer_range.start;
4295                        if metadata_buffer_range.end > region_buffer_start {
4296                            end_position =
4297                                end_position + (metadata_buffer_range.end - region_buffer_start);
4298                        }
4299                        end_position = end_position.min(end_region.range.end);
4300                    }
4301
4302                    if start_position <= query_range.end && end_position >= query_range.start {
4303                        return Some((start_position..end_position, metadata, excerpt));
4304                    }
4305                }
4306                // When there are no more metadata items for this excerpt, move to the next excerpt.
4307                else {
4308                    current_excerpt_metadata.take();
4309                    if let Some((end_excerpt_id, _)) = range_end
4310                        && excerpt.id == end_excerpt_id
4311                    {
4312                        return None;
4313                    }
4314                    cursor.next_excerpt_forwards();
4315                }
4316            }
4317        })
4318    }
4319
4320    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4321        let offset = position.to_offset(self);
4322
4323        let mut cursor = self
4324            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4325            );
4326        cursor.seek(&DimensionPair {
4327            key: offset,
4328            value: None,
4329        });
4330        cursor.seek_to_start_of_current_excerpt();
4331        let excerpt = cursor.excerpt()?;
4332
4333        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4334        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4335        let current_position = self
4336            .anchor_before(offset)
4337            .text_anchor
4338            .to_offset(&excerpt.buffer);
4339
4340        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4341            if diff.is_inverted {
4342                for hunk in diff.hunks_intersecting_base_text_range_rev(
4343                    excerpt_start..excerpt_end,
4344                    diff.original_buffer_snapshot(),
4345                ) {
4346                    if hunk.diff_base_byte_range.end >= current_position {
4347                        continue;
4348                    }
4349                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4350                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4351                    return Some(MultiBufferRow(start.row));
4352                }
4353            } else {
4354                let excerpt_end = excerpt
4355                    .buffer
4356                    .anchor_before(excerpt_end.min(current_position));
4357                for hunk in diff.hunks_intersecting_range_rev(
4358                    excerpt.range.context.start..excerpt_end,
4359                    &excerpt.buffer,
4360                ) {
4361                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4362                    if hunk_end >= current_position {
4363                        continue;
4364                    }
4365                    let start =
4366                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4367                    return Some(MultiBufferRow(start.row));
4368                }
4369            }
4370        }
4371
4372        loop {
4373            cursor.prev_excerpt();
4374            let excerpt = cursor.excerpt()?;
4375
4376            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4377                continue;
4378            };
4379            if diff.is_inverted {
4380                let Some(hunk) = diff
4381                    .hunks_intersecting_base_text_range_rev(
4382                        excerpt.range.context.to_offset(&excerpt.buffer),
4383                        diff.original_buffer_snapshot(),
4384                    )
4385                    .next()
4386                else {
4387                    continue;
4388                };
4389                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4390                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4391                return Some(MultiBufferRow(start.row));
4392            } else {
4393                let Some(hunk) = diff
4394                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4395                    .next()
4396                else {
4397                    continue;
4398                };
4399                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4400                return Some(MultiBufferRow(start.row));
4401            }
4402        }
4403    }
4404
4405    pub fn has_diff_hunks(&self) -> bool {
4406        self.diffs.values().any(|diff| !diff.is_empty())
4407    }
4408
4409    pub fn is_inside_word<T: ToOffset>(
4410        &self,
4411        position: T,
4412        scope_context: Option<CharScopeContext>,
4413    ) -> bool {
4414        let position = position.to_offset(self);
4415        let classifier = self
4416            .char_classifier_at(position)
4417            .scope_context(scope_context);
4418        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4419        let prev_char_kind = self
4420            .reversed_chars_at(position)
4421            .next()
4422            .map(|c| classifier.kind(c));
4423        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4424    }
4425
4426    pub fn surrounding_word<T: ToOffset>(
4427        &self,
4428        start: T,
4429        scope_context: Option<CharScopeContext>,
4430    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4431        let mut start = start.to_offset(self);
4432        let mut end = start;
4433        let mut next_chars = self.chars_at(start).peekable();
4434        let mut prev_chars = self.reversed_chars_at(start).peekable();
4435
4436        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4437
4438        let word_kind = cmp::max(
4439            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4440            next_chars.peek().copied().map(|c| classifier.kind(c)),
4441        );
4442
4443        for ch in prev_chars {
4444            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4445                start -= ch.len_utf8();
4446            } else {
4447                break;
4448            }
4449        }
4450
4451        for ch in next_chars {
4452            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4453                end += ch.len_utf8();
4454            } else {
4455                break;
4456            }
4457        }
4458
4459        (start..end, word_kind)
4460    }
4461
4462    pub fn char_kind_before<T: ToOffset>(
4463        &self,
4464        start: T,
4465        scope_context: Option<CharScopeContext>,
4466    ) -> Option<CharKind> {
4467        let start = start.to_offset(self);
4468        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4469        self.reversed_chars_at(start)
4470            .next()
4471            .map(|ch| classifier.kind(ch))
4472    }
4473
4474    pub fn is_singleton(&self) -> bool {
4475        self.singleton
4476    }
4477
4478    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4479        if self.singleton {
4480            self.excerpts
4481                .iter()
4482                .next()
4483                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4484        } else {
4485            None
4486        }
4487    }
4488
4489    pub fn len(&self) -> MultiBufferOffset {
4490        self.diff_transforms.summary().output.len
4491    }
4492
4493    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4494        MBD::from_summary(&self.text_summary())
4495    }
4496
4497    pub fn is_empty(&self) -> bool {
4498        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4499    }
4500
4501    pub fn widest_line_number(&self) -> u32 {
4502        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4503        self.excerpts.summary().widest_line_number + 1
4504    }
4505
4506    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4507        let range = range.start.to_offset(self)..range.end.to_offset(self);
4508        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4509        excerpts.seek(&range.start);
4510
4511        let mut chunk;
4512        let mut has_trailing_newline;
4513        let excerpt_bytes;
4514        if let Some(region) = excerpts.region() {
4515            let mut bytes = region.buffer.bytes_in_range(
4516                region.buffer_range.start + (range.start - region.range.start)
4517                    ..(region.buffer_range.start + (range.end - region.range.start))
4518                        .min(region.buffer_range.end),
4519            );
4520            chunk = bytes.next().unwrap_or(&[][..]);
4521            excerpt_bytes = Some(bytes);
4522            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4523            if chunk.is_empty() && has_trailing_newline {
4524                chunk = b"\n";
4525                has_trailing_newline = false;
4526            }
4527        } else {
4528            chunk = &[][..];
4529            excerpt_bytes = None;
4530            has_trailing_newline = false;
4531        };
4532
4533        MultiBufferBytes {
4534            range,
4535            cursor: excerpts,
4536            excerpt_bytes,
4537            has_trailing_newline,
4538            chunk,
4539        }
4540    }
4541
4542    pub fn reversed_bytes_in_range<T: ToOffset>(
4543        &self,
4544        range: Range<T>,
4545    ) -> ReversedMultiBufferBytes<'_> {
4546        let range = range.start.to_offset(self)..range.end.to_offset(self);
4547        let mut chunks = self.reversed_chunks_in_range(range.clone());
4548        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4549        ReversedMultiBufferBytes {
4550            range,
4551            chunks,
4552            chunk,
4553        }
4554    }
4555
4556    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4557        let mut cursor = self.cursor::<Point, Point>();
4558        cursor.seek(&Point::new(start_row.0, 0));
4559        let mut result = MultiBufferRows {
4560            point: Point::new(0, 0),
4561            is_empty: self.excerpts.is_empty(),
4562            is_singleton: self.is_singleton(),
4563            cursor,
4564        };
4565        result.seek(start_row);
4566        result
4567    }
4568
4569    pub fn chunks<T: ToOffset>(
4570        &self,
4571        range: Range<T>,
4572        language_aware: bool,
4573    ) -> MultiBufferChunks<'_> {
4574        let mut chunks = MultiBufferChunks {
4575            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4576                ..ExcerptDimension(MultiBufferOffset::ZERO),
4577            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4578            excerpts: self.excerpts.cursor(()),
4579            diff_transforms: self.diff_transforms.cursor(()),
4580            diffs: &self.diffs,
4581            diff_base_chunks: None,
4582            excerpt_chunks: None,
4583            buffer_chunk: None,
4584            language_aware,
4585        };
4586        let range = range.start.to_offset(self)..range.end.to_offset(self);
4587        chunks.seek(range);
4588        chunks
4589    }
4590
4591    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4592        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4593    }
4594
4595    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4596        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4597    }
4598
4599    pub fn clip_offset_utf16(
4600        &self,
4601        offset: MultiBufferOffsetUtf16,
4602        bias: Bias,
4603    ) -> MultiBufferOffsetUtf16 {
4604        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4605    }
4606
4607    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4608        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4609            buffer.clip_point_utf16(Unclipped(point), bias)
4610        })
4611    }
4612
4613    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4614        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4615    }
4616
4617    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4618        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4619    }
4620
4621    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4622        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4623    }
4624
4625    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4626        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4627    }
4628
4629    #[instrument(skip_all)]
4630    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4631        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4632    }
4633
4634    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4635        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4636    }
4637
4638    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4639        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4640    }
4641
4642    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4643        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4644    }
4645
4646    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4647        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4648    }
4649
4650    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4651        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4652    }
4653
4654    fn clip_dimension<MBD, BD>(
4655        &self,
4656        position: MBD,
4657        bias: Bias,
4658        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4659    ) -> MBD
4660    where
4661        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4662        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4663    {
4664        let mut cursor = self.cursor::<MBD, BD>();
4665        cursor.seek(&position);
4666        if let Some(region) = cursor.region() {
4667            if position >= region.range.end {
4668                return region.range.end;
4669            }
4670            let overshoot = position - region.range.start;
4671            let mut buffer_position = region.buffer_range.start;
4672            buffer_position += overshoot;
4673            let clipped_buffer_position =
4674                clip_buffer_position(region.buffer, buffer_position, bias);
4675            let mut position = region.range.start;
4676            position += clipped_buffer_position - region.buffer_range.start;
4677            position
4678        } else {
4679            self.max_position()
4680        }
4681    }
4682
4683    #[instrument(skip_all)]
4684    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4685        &self,
4686        key: MBR1,
4687        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4688    ) -> MBR2
4689    where
4690        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4691        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4692        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4693        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4694    {
4695        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4696        cursor.seek(&DimensionPair { key, value: None });
4697        if let Some(region) = cursor.region() {
4698            if key >= region.range.end.key {
4699                return region.range.end.value.unwrap();
4700            }
4701            let start_key = region.range.start.key;
4702            let start_value = region.range.start.value.unwrap();
4703            let buffer_start_key = region.buffer_range.start.key;
4704            let buffer_start_value = region.buffer_range.start.value.unwrap();
4705            let mut buffer_key = buffer_start_key;
4706            buffer_key += key - start_key;
4707            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4708            let mut result = start_value;
4709            result += buffer_value - buffer_start_value;
4710            result
4711        } else {
4712            self.max_position()
4713        }
4714    }
4715
4716    pub fn point_to_buffer_offset<T: ToOffset>(
4717        &self,
4718        point: T,
4719    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4720        let offset = point.to_offset(self);
4721        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4722        cursor.seek(&offset);
4723        let region = cursor.region()?;
4724        let overshoot = offset - region.range.start;
4725        let buffer_offset = region.buffer_range.start + overshoot;
4726        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4727            && region.has_trailing_newline
4728            && !region.is_main_buffer
4729        {
4730            let main_buffer_position = cursor.main_buffer_position()?;
4731            let buffer_snapshot = &cursor.excerpt()?.buffer;
4732            return Some((buffer_snapshot, main_buffer_position));
4733        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4734            return None;
4735        }
4736        Some((region.buffer, buffer_offset))
4737    }
4738
4739    pub fn point_to_buffer_point(
4740        &self,
4741        point: Point,
4742    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4743        let mut cursor = self.cursor::<Point, Point>();
4744        cursor.seek(&point);
4745        let region = cursor.region()?;
4746        let overshoot = point - region.range.start;
4747        let buffer_point = region.buffer_range.start + overshoot;
4748        let excerpt = cursor.excerpt()?;
4749        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4750            && region.has_trailing_newline
4751            && !region.is_main_buffer
4752        {
4753            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4754        } else if buffer_point > region.buffer.max_point() {
4755            return None;
4756        }
4757        Some((region.buffer, buffer_point, excerpt.id))
4758    }
4759
4760    pub fn suggested_indents(
4761        &self,
4762        rows: impl IntoIterator<Item = u32>,
4763        cx: &App,
4764    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4765        let mut result = BTreeMap::new();
4766        self.suggested_indents_callback(
4767            rows,
4768            |row, indent| {
4769                result.insert(row, indent);
4770                ControlFlow::Continue(())
4771            },
4772            cx,
4773        );
4774        result
4775    }
4776
4777    // move this to be a generator once those are a thing
4778    pub fn suggested_indents_callback(
4779        &self,
4780        rows: impl IntoIterator<Item = u32>,
4781        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4782        cx: &App,
4783    ) {
4784        let mut rows_for_excerpt = Vec::new();
4785        let mut cursor = self.cursor::<Point, Point>();
4786        let mut rows = rows.into_iter().peekable();
4787        let mut prev_row = u32::MAX;
4788        let mut prev_language_indent_size = IndentSize::default();
4789
4790        while let Some(row) = rows.next() {
4791            cursor.seek(&Point::new(row, 0));
4792            let Some(region) = cursor.region() else {
4793                continue;
4794            };
4795
4796            // Retrieve the language and indent size once for each disjoint region being indented.
4797            let single_indent_size = if row.saturating_sub(1) == prev_row {
4798                prev_language_indent_size
4799            } else {
4800                region
4801                    .buffer
4802                    .language_indent_size_at(Point::new(row, 0), cx)
4803            };
4804            prev_language_indent_size = single_indent_size;
4805            prev_row = row;
4806
4807            let start_buffer_row = region.buffer_range.start.row;
4808            let start_multibuffer_row = region.range.start.row;
4809            let end_multibuffer_row = region.range.end.row;
4810
4811            rows_for_excerpt.push(row);
4812            while let Some(next_row) = rows.peek().copied() {
4813                if end_multibuffer_row > next_row {
4814                    rows_for_excerpt.push(next_row);
4815                    rows.next();
4816                } else {
4817                    break;
4818                }
4819            }
4820
4821            let buffer_rows = rows_for_excerpt
4822                .drain(..)
4823                .map(|row| start_buffer_row + row - start_multibuffer_row);
4824            let buffer_indents = region
4825                .buffer
4826                .suggested_indents(buffer_rows, single_indent_size);
4827            for (row, indent) in buffer_indents {
4828                if cb(
4829                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4830                    indent,
4831                )
4832                .is_break()
4833                {
4834                    return;
4835                }
4836            }
4837        }
4838    }
4839
4840    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4841        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4842            let mut size = buffer.indent_size_for_line(range.start.row);
4843            size.len = size
4844                .len
4845                .min(range.end.column)
4846                .saturating_sub(range.start.column);
4847            size
4848        } else {
4849            IndentSize::spaces(0)
4850        }
4851    }
4852
4853    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4854        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4855            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4856        } else {
4857            LineIndent::spaces(0)
4858        }
4859    }
4860
4861    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4862        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4863
4864        if self.language_settings(cx).extend_comment_on_newline
4865            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4866        {
4867            let delimiters = language_scope.line_comment_prefixes();
4868            for delimiter in delimiters {
4869                if *self
4870                    .chars_at(Point::new(row.0, indent.len() as u32))
4871                    .take(delimiter.chars().count())
4872                    .collect::<String>()
4873                    .as_str()
4874                    == **delimiter
4875                {
4876                    indent.push_str(delimiter);
4877                    break;
4878                }
4879            }
4880        }
4881
4882        indent
4883    }
4884
4885    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4886    where
4887        T: ToOffset,
4888    {
4889        for char in self.reversed_chars_at(position) {
4890            if !char.is_whitespace() {
4891                return false;
4892            }
4893            if char == '\n' {
4894                return true;
4895            }
4896        }
4897        true
4898    }
4899
4900    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4901        while row.0 > 0 {
4902            row.0 -= 1;
4903            if !self.is_line_blank(row) {
4904                return Some(row);
4905            }
4906        }
4907        None
4908    }
4909
4910    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4911        if let Some((_, range)) = self.buffer_line_for_row(row) {
4912            range.end.column - range.start.column
4913        } else {
4914            0
4915        }
4916    }
4917
4918    pub fn buffer_line_for_row(
4919        &self,
4920        row: MultiBufferRow,
4921    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4922        let mut cursor = self.cursor::<Point, Point>();
4923        let point = Point::new(row.0, 0);
4924        cursor.seek(&point);
4925        let region = cursor.region()?;
4926        let overshoot = point.min(region.range.end) - region.range.start;
4927        let buffer_point = region.buffer_range.start + overshoot;
4928        if buffer_point.row > region.buffer_range.end.row {
4929            return None;
4930        }
4931        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4932        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4933            .min(region.buffer_range.end);
4934        Some((region.buffer, line_start..line_end))
4935    }
4936
4937    pub fn max_point(&self) -> Point {
4938        self.text_summary().lines
4939    }
4940
4941    pub fn max_row(&self) -> MultiBufferRow {
4942        MultiBufferRow(self.text_summary().lines.row)
4943    }
4944
4945    pub fn text_summary(&self) -> MBTextSummary {
4946        self.diff_transforms.summary().output
4947    }
4948
4949    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4950    where
4951        MBD: MultiBufferDimension + AddAssign,
4952        O: ToOffset,
4953    {
4954        let range = range.start.to_offset(self)..range.end.to_offset(self);
4955        let mut cursor = self
4956            .diff_transforms
4957            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4958        cursor.seek(&range.start, Bias::Right);
4959
4960        let Some(first_transform) = cursor.item() else {
4961            return MBD::from_summary(&MBTextSummary::default());
4962        };
4963
4964        let diff_transform_start = cursor.start().0;
4965        let diff_transform_end = cursor.end().0;
4966        let diff_start = range.start;
4967        let start_overshoot = diff_start - diff_transform_start;
4968        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4969
4970        let mut result = match first_transform {
4971            DiffTransform::BufferContent { .. } => {
4972                let excerpt_start = cursor.start().1 + start_overshoot;
4973                let excerpt_end = cursor.start().1 + end_overshoot;
4974                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4975            }
4976            DiffTransform::DeletedHunk {
4977                buffer_id,
4978                base_text_byte_range,
4979                has_trailing_newline,
4980                ..
4981            } => {
4982                let buffer_start = base_text_byte_range.start + start_overshoot;
4983                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4984                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4985                    panic!("{:?} is in non-existent deleted hunk", range.start)
4986                };
4987
4988                let include_trailing_newline =
4989                    *has_trailing_newline && range.end >= diff_transform_end;
4990                if include_trailing_newline {
4991                    buffer_end -= 1;
4992                }
4993
4994                let mut summary = base_text
4995                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4996
4997                if include_trailing_newline {
4998                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4999                        &TextSummary::newline(),
5000                    ))
5001                }
5002
5003                let mut result = MBD::default();
5004                result.add_text_dim(&summary);
5005                result
5006            }
5007        };
5008        if range.end < diff_transform_end {
5009            return result;
5010        }
5011
5012        cursor.next();
5013        result.add_mb_text_summary(
5014            &cursor
5015                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5016                .0,
5017        );
5018
5019        let Some(last_transform) = cursor.item() else {
5020            return result;
5021        };
5022
5023        let overshoot = range.end - cursor.start().0;
5024        let suffix = match last_transform {
5025            DiffTransform::BufferContent { .. } => {
5026                let end = cursor.start().1 + overshoot;
5027                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5028            }
5029            DiffTransform::DeletedHunk {
5030                base_text_byte_range,
5031                buffer_id,
5032                has_trailing_newline,
5033                ..
5034            } => {
5035                let buffer_end = base_text_byte_range.start + overshoot;
5036                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5037                    panic!("{:?} is in non-existent deleted hunk", range.end)
5038                };
5039
5040                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5041                    base_text_byte_range.start..buffer_end,
5042                );
5043                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5044                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5045                        &TextSummary::from("\n"),
5046                    ))
5047                }
5048
5049                let mut result = MBD::default();
5050                result.add_text_dim(&suffix);
5051                result
5052            }
5053        };
5054
5055        result += suffix;
5056        result
5057    }
5058
5059    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5060    where
5061        MBD: MultiBufferDimension + AddAssign,
5062    {
5063        let mut summary = MBD::default();
5064        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5065        cursor.seek(&range.start, Bias::Right);
5066        if let Some(excerpt) = cursor.item() {
5067            let mut end_before_newline = cursor.end();
5068            if excerpt.has_trailing_newline {
5069                end_before_newline -= 1;
5070            }
5071
5072            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5073            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5074            let end_in_excerpt =
5075                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5076            summary.add_text_dim(
5077                &excerpt
5078                    .buffer
5079                    .text_summary_for_range::<MBD::TextDimension, _>(
5080                        start_in_excerpt..end_in_excerpt,
5081                    ),
5082            );
5083
5084            if range.end > end_before_newline {
5085                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5086            }
5087
5088            cursor.next();
5089        }
5090
5091        if range.end > *cursor.start() {
5092            summary += cursor
5093                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5094                .0;
5095            if let Some(excerpt) = cursor.item() {
5096                range.end = cmp::max(*cursor.start(), range.end);
5097
5098                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5099                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5100                summary.add_text_dim(
5101                    &excerpt
5102                        .buffer
5103                        .text_summary_for_range::<MBD::TextDimension, _>(
5104                            excerpt_start..end_in_excerpt,
5105                        ),
5106                );
5107            }
5108        }
5109
5110        summary
5111    }
5112
5113    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5114    where
5115        MBD: MultiBufferDimension
5116            + Ord
5117            + Sub<Output = MBD::TextDimension>
5118            + Sub<MBD::TextDimension, Output = MBD>
5119            + AddAssign<MBD::TextDimension>
5120            + Add<MBD::TextDimension, Output = MBD>,
5121        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5122    {
5123        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5124        let locator = self.excerpt_locator_for_id(excerpt_id);
5125        let (start, _, mut item) = self
5126            .excerpts
5127            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5128        let mut start = MBD::from_summary(&start.text);
5129        if item.is_none() && excerpt_id == ExcerptId::max() {
5130            item = self.excerpts.last();
5131            if let Some(last_summary) = self.excerpts.last_summary() {
5132                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5133            }
5134        }
5135
5136        if self.diff_transforms.is_empty() {
5137            let excerpt_start_position = ExcerptDimension(start);
5138            if let Some(excerpt) = item {
5139                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5140                    return excerpt_start_position.0;
5141                }
5142                let excerpt_buffer_start = excerpt
5143                    .range
5144                    .context
5145                    .start
5146                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5147                let excerpt_buffer_end = excerpt
5148                    .range
5149                    .context
5150                    .end
5151                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5152                let buffer_summary = anchor
5153                    .text_anchor
5154                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5155                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5156                let mut position = excerpt_start_position;
5157                if summary > excerpt_buffer_start {
5158                    position += summary - excerpt_buffer_start;
5159                }
5160
5161                position.0
5162            } else {
5163                excerpt_start_position.0
5164            }
5165        } else {
5166            let mut diff_transforms_cursor = self
5167                .diff_transforms
5168                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5169            diff_transforms_cursor.next();
5170
5171            let excerpt_start_position = ExcerptDimension(start);
5172            if let Some(excerpt) = item {
5173                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5174                    return self.resolve_summary_for_anchor(
5175                        &Anchor::min(),
5176                        excerpt_start_position,
5177                        &mut diff_transforms_cursor,
5178                    );
5179                }
5180                let excerpt_buffer_start = excerpt
5181                    .range
5182                    .context
5183                    .start
5184                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5185                let excerpt_buffer_end = excerpt
5186                    .range
5187                    .context
5188                    .end
5189                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5190                let buffer_summary = anchor
5191                    .text_anchor
5192                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5193                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5194                let mut position = excerpt_start_position;
5195                if summary > excerpt_buffer_start {
5196                    position += summary - excerpt_buffer_start;
5197                }
5198
5199                if diff_transforms_cursor.start().0 < position {
5200                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5201                }
5202                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5203            } else {
5204                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5205                self.resolve_summary_for_anchor(
5206                    &Anchor::max(),
5207                    excerpt_start_position,
5208                    &mut diff_transforms_cursor,
5209                )
5210            }
5211        }
5212    }
5213
5214    fn resolve_summary_for_anchor<MBD>(
5215        &self,
5216        anchor: &Anchor,
5217        excerpt_position: ExcerptDimension<MBD>,
5218        diff_transforms: &mut Cursor<
5219            DiffTransform,
5220            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5221        >,
5222    ) -> MBD
5223    where
5224        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5225    {
5226        loop {
5227            let transform_end_position = diff_transforms.end().0;
5228            let at_transform_end =
5229                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5230            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5231                diff_transforms.next();
5232                continue;
5233            }
5234
5235            let mut position = diff_transforms.start().1;
5236            match diff_transforms.item() {
5237                Some(DiffTransform::DeletedHunk {
5238                    buffer_id,
5239                    base_text_byte_range,
5240                    ..
5241                }) => {
5242                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5243                        && let Some(base_text) =
5244                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5245                        && diff_base_anchor.is_valid(&base_text)
5246                    {
5247                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5248                        if base_text_offset >= base_text_byte_range.start
5249                            && base_text_offset <= base_text_byte_range.end
5250                        {
5251                            let position_in_hunk = base_text
5252                                .text_summary_for_range::<MBD::TextDimension, _>(
5253                                    base_text_byte_range.start..base_text_offset,
5254                                );
5255                            position.0.add_text_dim(&position_in_hunk);
5256                        } else if at_transform_end {
5257                            diff_transforms.next();
5258                            continue;
5259                        }
5260                    }
5261                }
5262                _ => {
5263                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5264                        diff_transforms.next();
5265                        continue;
5266                    }
5267                    let overshoot = excerpt_position - diff_transforms.start().0;
5268                    position += overshoot;
5269                }
5270            }
5271
5272            return position.0;
5273        }
5274    }
5275
5276    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5277        let mut cursor = self
5278            .excerpts
5279            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5280        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5281
5282        cursor.seek(&Some(locator), Bias::Left);
5283        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5284            cursor.prev();
5285        }
5286
5287        let mut position = cursor.start().1;
5288        if let Some(excerpt) = cursor.item()
5289            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5290        {
5291            let excerpt_buffer_start = excerpt
5292                .buffer
5293                .offset_for_anchor(&excerpt.range.context.start);
5294            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5295            let buffer_position = cmp::min(
5296                excerpt_buffer_end,
5297                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5298            );
5299            if buffer_position > excerpt_buffer_start {
5300                position += buffer_position - excerpt_buffer_start;
5301            }
5302        }
5303        position
5304    }
5305
5306    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5307        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5308            excerpt_id = *replacement;
5309        }
5310        excerpt_id
5311    }
5312
5313    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5314    where
5315        MBD: MultiBufferDimension
5316            + Ord
5317            + Sub<Output = MBD::TextDimension>
5318            + AddAssign<MBD::TextDimension>,
5319        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5320        I: 'a + IntoIterator<Item = &'a Anchor>,
5321    {
5322        let mut anchors = anchors.into_iter().peekable();
5323        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5324        let mut diff_transforms_cursor = self
5325            .diff_transforms
5326            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5327        diff_transforms_cursor.next();
5328
5329        let mut summaries = Vec::new();
5330        while let Some(anchor) = anchors.peek() {
5331            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5332
5333            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5334                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5335            });
5336
5337            let locator = self.excerpt_locator_for_id(excerpt_id);
5338            cursor.seek_forward(locator, Bias::Left);
5339            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5340                cursor.prev();
5341            }
5342
5343            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5344            if let Some(excerpt) = cursor.item() {
5345                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5346                    let position = self.resolve_summary_for_anchor(
5347                        &Anchor::min(),
5348                        excerpt_start_position,
5349                        &mut diff_transforms_cursor,
5350                    );
5351                    summaries.extend(excerpt_anchors.map(|_| position));
5352                    continue;
5353                }
5354                let excerpt_buffer_start = excerpt
5355                    .range
5356                    .context
5357                    .start
5358                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5359                let excerpt_buffer_end = excerpt
5360                    .range
5361                    .context
5362                    .end
5363                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5364                for (buffer_summary, anchor) in excerpt
5365                    .buffer
5366                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5367                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5368                    )
5369                {
5370                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5371                    let mut position = excerpt_start_position;
5372                    if summary > excerpt_buffer_start {
5373                        position += summary - excerpt_buffer_start;
5374                    }
5375
5376                    if diff_transforms_cursor.start().0 < position {
5377                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5378                    }
5379
5380                    summaries.push(self.resolve_summary_for_anchor(
5381                        anchor,
5382                        position,
5383                        &mut diff_transforms_cursor,
5384                    ));
5385                }
5386            } else {
5387                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5388                let position = self.resolve_summary_for_anchor(
5389                    &Anchor::max(),
5390                    excerpt_start_position,
5391                    &mut diff_transforms_cursor,
5392                );
5393                summaries.extend(excerpt_anchors.map(|_| position));
5394            }
5395        }
5396
5397        summaries
5398    }
5399
5400    pub fn dimensions_from_points<'a, MBD>(
5401        &'a self,
5402        points: impl 'a + IntoIterator<Item = Point>,
5403    ) -> impl 'a + Iterator<Item = MBD>
5404    where
5405        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5406    {
5407        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5408        cursor.seek(&DimensionPair {
5409            key: Point::default(),
5410            value: None,
5411        });
5412        let mut points = points.into_iter();
5413        iter::from_fn(move || {
5414            let point = points.next()?;
5415
5416            cursor.seek_forward(&DimensionPair {
5417                key: point,
5418                value: None,
5419            });
5420
5421            if let Some(region) = cursor.region() {
5422                let overshoot = point - region.range.start.key;
5423                let buffer_point = region.buffer_range.start + overshoot;
5424                let mut position = region.range.start.value.unwrap();
5425                position.add_text_dim(
5426                    &region
5427                        .buffer
5428                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5429                );
5430                if point == region.range.end.key && region.has_trailing_newline {
5431                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5432                }
5433                Some(position)
5434            } else {
5435                Some(MBD::from_summary(&self.text_summary()))
5436            }
5437        })
5438    }
5439
5440    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5441    where
5442        I: 'a + IntoIterator<Item = &'a Anchor>,
5443    {
5444        let mut anchors = anchors.into_iter().enumerate().peekable();
5445        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5446        cursor.next();
5447
5448        let mut result = Vec::new();
5449
5450        while let Some((_, anchor)) = anchors.peek() {
5451            let old_excerpt_id = anchor.excerpt_id;
5452
5453            // Find the location where this anchor's excerpt should be.
5454            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5455            cursor.seek_forward(&Some(old_locator), Bias::Left);
5456
5457            let next_excerpt = cursor.item();
5458            let prev_excerpt = cursor.prev_item();
5459
5460            // Process all of the anchors for this excerpt.
5461            while let Some((anchor_ix, &anchor)) =
5462                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5463            {
5464                let mut anchor = anchor;
5465
5466                // Leave min and max anchors unchanged if invalid or
5467                // if the old excerpt still exists at this location
5468                let mut kept_position = next_excerpt
5469                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5470                    || old_excerpt_id == ExcerptId::max()
5471                    || old_excerpt_id == ExcerptId::min();
5472
5473                // If the old excerpt no longer exists at this location, then attempt to
5474                // find an equivalent position for this anchor in an adjacent excerpt.
5475                if !kept_position {
5476                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5477                        if excerpt.contains(&anchor) {
5478                            anchor.excerpt_id = excerpt.id;
5479                            kept_position = true;
5480                            break;
5481                        }
5482                    }
5483                }
5484
5485                // If there's no adjacent excerpt that contains the anchor's position,
5486                // then report that the anchor has lost its position.
5487                if !kept_position {
5488                    anchor = if let Some(excerpt) = next_excerpt {
5489                        let mut text_anchor = excerpt
5490                            .range
5491                            .context
5492                            .start
5493                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5494                        if text_anchor
5495                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5496                            .is_gt()
5497                        {
5498                            text_anchor = excerpt.range.context.end;
5499                        }
5500                        Anchor::in_buffer(excerpt.id, text_anchor)
5501                    } else if let Some(excerpt) = prev_excerpt {
5502                        let mut text_anchor = excerpt
5503                            .range
5504                            .context
5505                            .end
5506                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5507                        if text_anchor
5508                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5509                            .is_lt()
5510                        {
5511                            text_anchor = excerpt.range.context.start;
5512                        }
5513                        Anchor::in_buffer(excerpt.id, text_anchor)
5514                    } else if anchor.text_anchor.bias == Bias::Left {
5515                        Anchor::min()
5516                    } else {
5517                        Anchor::max()
5518                    };
5519                }
5520
5521                result.push((anchor_ix, anchor, kept_position));
5522            }
5523        }
5524        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5525        result
5526    }
5527
5528    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5529        self.anchor_at(position, Bias::Left)
5530    }
5531
5532    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5533        self.anchor_at(position, Bias::Right)
5534    }
5535
5536    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5537        let offset = position.to_offset(self);
5538
5539        // Find the given position in the diff transforms. Determine the corresponding
5540        // offset in the excerpts, and whether the position is within a deleted hunk.
5541        let mut diff_transforms = self
5542            .diff_transforms
5543            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5544        diff_transforms.seek(&offset, Bias::Right);
5545
5546        if offset == diff_transforms.start().0
5547            && bias == Bias::Left
5548            && let Some(prev_item) = diff_transforms.prev_item()
5549            && let DiffTransform::DeletedHunk { .. } = prev_item
5550        {
5551            diff_transforms.prev();
5552        }
5553        let offset_in_transform = offset - diff_transforms.start().0;
5554        let mut excerpt_offset = diff_transforms.start().1;
5555        let mut diff_base_anchor = None;
5556        if let Some(DiffTransform::DeletedHunk {
5557            buffer_id,
5558            base_text_byte_range,
5559            has_trailing_newline,
5560            ..
5561        }) = diff_transforms.item()
5562        {
5563            let diff = self.diffs.get(buffer_id).expect("missing diff");
5564            if offset_in_transform > base_text_byte_range.len() {
5565                debug_assert!(*has_trailing_newline);
5566                bias = Bias::Right;
5567            } else {
5568                diff_base_anchor = Some(
5569                    diff.base_text()
5570                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5571                );
5572                bias = Bias::Left;
5573            }
5574        } else {
5575            excerpt_offset += MultiBufferOffset(offset_in_transform);
5576        };
5577
5578        let mut excerpts = self
5579            .excerpts
5580            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5581        excerpts.seek(&excerpt_offset, Bias::Right);
5582        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5583            excerpts.prev();
5584        }
5585        if let Some(excerpt) = excerpts.item() {
5586            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5587            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5588                overshoot -= 1;
5589                bias = Bias::Right;
5590            }
5591
5592            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5593            let text_anchor =
5594                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5595            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5596            match diff_base_anchor {
5597                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5598                None => anchor,
5599            }
5600        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5601        {
5602            Anchor::min()
5603        } else {
5604            Anchor::max()
5605        }
5606    }
5607
5608    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5609    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5610        let (excerpt, buffer, _) = self.as_singleton()?;
5611        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5612            Some(Anchor::in_buffer(*excerpt, text_anchor))
5613        } else {
5614            None
5615        }
5616    }
5617
5618    /// Returns an anchor for the given excerpt and text anchor,
5619    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5620    pub fn anchor_range_in_excerpt(
5621        &self,
5622        excerpt_id: ExcerptId,
5623        text_anchor: Range<text::Anchor>,
5624    ) -> Option<Range<Anchor>> {
5625        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5626
5627        Some(
5628            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5629                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5630        )
5631    }
5632
5633    /// Returns an anchor for the given excerpt and text anchor,
5634    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5635    pub fn anchor_in_excerpt(
5636        &self,
5637        excerpt_id: ExcerptId,
5638        text_anchor: text::Anchor,
5639    ) -> Option<Anchor> {
5640        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5641        Self::anchor_in_excerpt_(excerpt, text_anchor)
5642    }
5643
5644    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5645    pub fn anchors_in_excerpt(
5646        &self,
5647        excerpt_id: ExcerptId,
5648        text_anchors: impl IntoIterator<Item = text::Anchor>,
5649    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5650        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5651        Some(
5652            text_anchors
5653                .into_iter()
5654                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5655        )
5656    }
5657
5658    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5659        match text_anchor.buffer_id {
5660            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5661            Some(_) => return None,
5662            None if text_anchor.is_max() || text_anchor.is_min() => {
5663                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5664            }
5665            None => return None,
5666        }
5667
5668        let context = &excerpt.range.context;
5669        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5670            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5671        {
5672            return None;
5673        }
5674
5675        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5676    }
5677
5678    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5679        Some(self.excerpt(excerpt_id)?.range.context.clone())
5680    }
5681
5682    pub fn excerpt_range_for_excerpt(
5683        &self,
5684        excerpt_id: ExcerptId,
5685    ) -> Option<ExcerptRange<text::Anchor>> {
5686        Some(self.excerpt(excerpt_id)?.range.clone())
5687    }
5688
5689    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5690        if anchor.is_min() || anchor.is_max() {
5691            // todo(lw): should be `!self.is_empty()`
5692            true
5693        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5694            excerpt.buffer.can_resolve(&anchor.text_anchor)
5695        } else {
5696            false
5697        }
5698    }
5699
5700    pub fn excerpts(
5701        &self,
5702    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5703        self.excerpts
5704            .iter()
5705            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5706    }
5707
5708    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5709    where
5710        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5711        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5712    {
5713        let excerpts = self.excerpts.cursor(());
5714        let diff_transforms = self.diff_transforms.cursor(());
5715        MultiBufferCursor {
5716            excerpts,
5717            diff_transforms,
5718            diffs: &self.diffs,
5719            cached_region: OnceCell::new(),
5720        }
5721    }
5722
5723    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5724        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5725        let mut excerpts = self
5726            .excerpts
5727            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5728        excerpts.seek(&Some(start_locator), Bias::Left);
5729        excerpts.prev();
5730
5731        let mut diff_transforms = self
5732            .diff_transforms
5733            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5734        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5735        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5736            diff_transforms.next();
5737        }
5738
5739        let excerpt = excerpts.item()?;
5740        Some(MultiBufferExcerpt {
5741            excerpt,
5742            offset: diff_transforms.start().output_dimension.0,
5743            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5744            excerpt_offset: excerpts.start().1,
5745            diff_transforms,
5746        })
5747    }
5748
5749    pub fn excerpt_boundaries_in_range<R, T>(
5750        &self,
5751        range: R,
5752    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5753    where
5754        R: RangeBounds<T>,
5755        T: ToOffset,
5756    {
5757        let start_offset;
5758        let start = match range.start_bound() {
5759            Bound::Included(start) => {
5760                start_offset = start.to_offset(self);
5761                Bound::Included(start_offset)
5762            }
5763            Bound::Excluded(_) => {
5764                panic!("not supported")
5765            }
5766            Bound::Unbounded => {
5767                start_offset = MultiBufferOffset::ZERO;
5768                Bound::Unbounded
5769            }
5770        };
5771        let end = match range.end_bound() {
5772            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5773            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5774            Bound::Unbounded => Bound::Unbounded,
5775        };
5776        let bounds = (start, end);
5777        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5778        cursor.seek(&DimensionPair {
5779            key: start_offset,
5780            value: None,
5781        });
5782
5783        if cursor
5784            .fetch_excerpt_with_range()
5785            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5786        {
5787            cursor.prev_excerpt();
5788        } else {
5789            cursor.seek_to_start_of_current_excerpt();
5790        }
5791        let mut prev_region = cursor
5792            .fetch_excerpt_with_range()
5793            .map(|(excerpt, _)| excerpt);
5794
5795        cursor.next_excerpt_forwards();
5796
5797        iter::from_fn(move || {
5798            loop {
5799                if self.singleton {
5800                    return None;
5801                }
5802
5803                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5804                cursor.next_excerpt_forwards();
5805                if !bounds.contains(&next_range.start.key) {
5806                    prev_region = Some(next_excerpt);
5807                    continue;
5808                }
5809
5810                let next_region_start = next_range.start.value.unwrap();
5811                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5812                    range.start.value.unwrap()
5813                } else {
5814                    self.max_point()
5815                };
5816
5817                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5818                    id: region.id,
5819                    buffer: region.buffer.clone(),
5820                    buffer_id: region.buffer_id,
5821                    range: region.range.clone(),
5822                    end_row: MultiBufferRow(next_region_start.row),
5823                });
5824
5825                let next = ExcerptInfo {
5826                    id: next_excerpt.id,
5827                    buffer: next_excerpt.buffer.clone(),
5828                    buffer_id: next_excerpt.buffer_id,
5829                    range: next_excerpt.range.clone(),
5830                    end_row: if next_excerpt.has_trailing_newline {
5831                        MultiBufferRow(next_region_end.row - 1)
5832                    } else {
5833                        MultiBufferRow(next_region_end.row)
5834                    },
5835                };
5836
5837                let row = MultiBufferRow(next_region_start.row);
5838
5839                prev_region = Some(next_excerpt);
5840
5841                return Some(ExcerptBoundary { row, prev, next });
5842            }
5843        })
5844    }
5845
5846    pub fn edit_count(&self) -> usize {
5847        self.edit_count
5848    }
5849
5850    pub fn non_text_state_update_count(&self) -> usize {
5851        self.non_text_state_update_count
5852    }
5853
5854    /// Returns the smallest enclosing bracket ranges containing the given range or
5855    /// None if no brackets contain range or the range is not contained in a single
5856    /// excerpt
5857    ///
5858    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5859    #[ztracing::instrument(skip_all)]
5860    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5861        &self,
5862        range: Range<T>,
5863        range_filter: Option<
5864            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5865        >,
5866    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5867        let range = range.start.to_offset(self)..range.end.to_offset(self);
5868        let mut excerpt = self.excerpt_containing(range.clone())?;
5869        let buffer = excerpt.buffer();
5870        let excerpt_buffer_range = excerpt.buffer_range();
5871
5872        // Filter to ranges contained in the excerpt
5873        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5874            excerpt_buffer_range.contains(&BufferOffset(open.start))
5875                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5876                && range_filter.is_none_or(|filter| {
5877                    filter(
5878                        buffer,
5879                        BufferOffset(open.start)..BufferOffset(close.end),
5880                        BufferOffset(close.start)..BufferOffset(close.end),
5881                    )
5882                })
5883        };
5884
5885        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5886            excerpt.map_range_to_buffer(range),
5887            Some(&range_filter),
5888        )?;
5889
5890        Some((
5891            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5892            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5893        ))
5894    }
5895
5896    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5897    /// not contained in a single excerpt
5898    pub fn enclosing_bracket_ranges<T: ToOffset>(
5899        &self,
5900        range: Range<T>,
5901    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5902    {
5903        let range = range.start.to_offset(self)..range.end.to_offset(self);
5904        let mut excerpt = self.excerpt_containing(range.clone())?;
5905
5906        Some(
5907            excerpt
5908                .buffer()
5909                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5910                .filter_map(move |pair| {
5911                    let open_range =
5912                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5913                    let close_range =
5914                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5915                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5916                        Some((
5917                            excerpt.map_range_from_buffer(open_range),
5918                            excerpt.map_range_from_buffer(close_range),
5919                        ))
5920                    } else {
5921                        None
5922                    }
5923                }),
5924        )
5925    }
5926
5927    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5928    /// not contained in a single excerpt
5929    pub fn text_object_ranges<T: ToOffset>(
5930        &self,
5931        range: Range<T>,
5932        options: TreeSitterOptions,
5933    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5934        let range = range.start.to_offset(self)..range.end.to_offset(self);
5935        self.excerpt_containing(range.clone())
5936            .map(|mut excerpt| {
5937                excerpt
5938                    .buffer()
5939                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5940                    .filter_map(move |(range, text_object)| {
5941                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5942                        if excerpt.contains_buffer_range(range.clone()) {
5943                            Some((excerpt.map_range_from_buffer(range), text_object))
5944                        } else {
5945                            None
5946                        }
5947                    })
5948            })
5949            .into_iter()
5950            .flatten()
5951    }
5952
5953    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5954    /// not contained in a single excerpt
5955    pub fn bracket_ranges<T: ToOffset>(
5956        &self,
5957        range: Range<T>,
5958    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5959    {
5960        let range = range.start.to_offset(self)..range.end.to_offset(self);
5961        let mut excerpt = self.excerpt_containing(range.clone())?;
5962        Some(
5963            excerpt
5964                .buffer()
5965                .bracket_ranges(excerpt.map_range_to_buffer(range))
5966                .filter_map(move |pair| {
5967                    let open_range =
5968                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5969                    let close_range =
5970                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5971                    excerpt
5972                        .contains_buffer_range(open_range.start..close_range.end)
5973                        .then(|| BracketMatch {
5974                            open_range: excerpt.map_range_from_buffer(open_range),
5975                            close_range: excerpt.map_range_from_buffer(close_range),
5976                            color_index: pair.color_index,
5977                            newline_only: pair.newline_only,
5978                            syntax_layer_depth: pair.syntax_layer_depth,
5979                        })
5980                })
5981                .map(BracketMatch::bracket_ranges),
5982        )
5983    }
5984
5985    pub fn redacted_ranges<'a, T: ToOffset>(
5986        &'a self,
5987        range: Range<T>,
5988        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5989    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5990        let range = range.start.to_offset(self)..range.end.to_offset(self);
5991        self.lift_buffer_metadata(range, move |buffer, range| {
5992            if redaction_enabled(buffer.file()) {
5993                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5994            } else {
5995                None
5996            }
5997        })
5998        .map(|(range, _, _)| range)
5999    }
6000
6001    pub fn runnable_ranges(
6002        &self,
6003        range: Range<Anchor>,
6004    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6005        let range = range.start.to_offset(self)..range.end.to_offset(self);
6006        self.lift_buffer_metadata(range, move |buffer, range| {
6007            Some(
6008                buffer
6009                    .runnable_ranges(range.clone())
6010                    .filter(move |runnable| {
6011                        runnable.run_range.start >= range.start
6012                            && runnable.run_range.end < range.end
6013                    })
6014                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6015            )
6016        })
6017        .map(|(run_range, runnable, _)| (run_range, runnable))
6018    }
6019
6020    pub fn line_indents(
6021        &self,
6022        start_row: MultiBufferRow,
6023        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6024    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6025        let max_point = self.max_point();
6026        let mut cursor = self.cursor::<Point, Point>();
6027        cursor.seek(&Point::new(start_row.0, 0));
6028        iter::from_fn(move || {
6029            let mut region = cursor.region()?;
6030            while !buffer_filter(&region.excerpt.buffer) {
6031                cursor.next();
6032                region = cursor.region()?;
6033            }
6034            let region = cursor.region()?;
6035            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6036            let buffer_start_row =
6037                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6038
6039            let buffer_end_row = if region.is_main_buffer
6040                && (region.has_trailing_newline || region.range.end == max_point)
6041            {
6042                region.buffer_range.end.row
6043            } else {
6044                region.buffer_range.end.row.saturating_sub(1)
6045            };
6046
6047            let line_indents = region
6048                .buffer
6049                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6050            let region_buffer_row = region.buffer_range.start.row;
6051            let region_row = region.range.start.row;
6052            let region_buffer = &region.excerpt.buffer;
6053            cursor.next();
6054            Some(line_indents.map(move |(buffer_row, indent)| {
6055                let row = region_row + (buffer_row - region_buffer_row);
6056                (MultiBufferRow(row), indent, region_buffer.as_ref())
6057            }))
6058        })
6059        .flatten()
6060    }
6061
6062    pub fn reversed_line_indents(
6063        &self,
6064        end_row: MultiBufferRow,
6065        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6066    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6067        let max_point = self.max_point();
6068        let mut cursor = self.cursor::<Point, Point>();
6069        cursor.seek(&Point::new(end_row.0, 0));
6070        iter::from_fn(move || {
6071            let mut region = cursor.region()?;
6072            while !buffer_filter(&region.excerpt.buffer) {
6073                cursor.prev();
6074                region = cursor.region()?;
6075            }
6076            let region = cursor.region()?;
6077
6078            let buffer_start_row = region.buffer_range.start.row;
6079            let buffer_end_row = if region.is_main_buffer
6080                && (region.has_trailing_newline || region.range.end == max_point)
6081            {
6082                region.buffer_range.end.row + 1
6083            } else {
6084                region.buffer_range.end.row
6085            };
6086
6087            let overshoot = end_row.0 - region.range.start.row;
6088            let buffer_end_row =
6089                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6090
6091            let line_indents = region
6092                .buffer
6093                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6094            let region_buffer_row = region.buffer_range.start.row;
6095            let region_row = region.range.start.row;
6096            let region_buffer = &region.excerpt.buffer;
6097            cursor.prev();
6098            Some(line_indents.map(move |(buffer_row, indent)| {
6099                let row = region_row + (buffer_row - region_buffer_row);
6100                (MultiBufferRow(row), indent, region_buffer.as_ref())
6101            }))
6102        })
6103        .flatten()
6104    }
6105
6106    pub async fn enclosing_indent(
6107        &self,
6108        mut target_row: MultiBufferRow,
6109    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6110        let max_row = MultiBufferRow(self.max_point().row);
6111        if target_row >= max_row {
6112            return None;
6113        }
6114
6115        let mut target_indent = self.line_indent_for_row(target_row);
6116
6117        // If the current row is at the start of an indented block, we want to return this
6118        // block as the enclosing indent.
6119        if !target_indent.is_line_empty() && target_row < max_row {
6120            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6121            if !next_line_indent.is_line_empty()
6122                && target_indent.raw_len() < next_line_indent.raw_len()
6123            {
6124                target_indent = next_line_indent;
6125                target_row.0 += 1;
6126            }
6127        }
6128
6129        const SEARCH_ROW_LIMIT: u32 = 25000;
6130        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6131        const YIELD_INTERVAL: u32 = 100;
6132
6133        let mut accessed_row_counter = 0;
6134
6135        // If there is a blank line at the current row, search for the next non indented lines
6136        if target_indent.is_line_empty() {
6137            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6138            let end =
6139                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6140
6141            let mut non_empty_line_above = None;
6142            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6143                if row < start {
6144                    break;
6145                }
6146                accessed_row_counter += 1;
6147                if accessed_row_counter == YIELD_INTERVAL {
6148                    accessed_row_counter = 0;
6149                    yield_now().await;
6150                }
6151                if !indent.is_line_empty() {
6152                    non_empty_line_above = Some((row, indent));
6153                    break;
6154                }
6155            }
6156
6157            let mut non_empty_line_below = None;
6158            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6159                if row > end {
6160                    break;
6161                }
6162                accessed_row_counter += 1;
6163                if accessed_row_counter == YIELD_INTERVAL {
6164                    accessed_row_counter = 0;
6165                    yield_now().await;
6166                }
6167                if !indent.is_line_empty() {
6168                    non_empty_line_below = Some((row, indent));
6169                    break;
6170                }
6171            }
6172
6173            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6174                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6175                    if above_indent.raw_len() >= below_indent.raw_len() {
6176                        (above_row, above_indent)
6177                    } else {
6178                        (below_row, below_indent)
6179                    }
6180                }
6181                (Some(above), None) => above,
6182                (None, Some(below)) => below,
6183                _ => return None,
6184            };
6185
6186            target_indent = indent;
6187            target_row = row;
6188        }
6189
6190        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6191        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6192
6193        let mut start_indent = None;
6194        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6195            if row < start {
6196                break;
6197            }
6198            accessed_row_counter += 1;
6199            if accessed_row_counter == YIELD_INTERVAL {
6200                accessed_row_counter = 0;
6201                yield_now().await;
6202            }
6203            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6204                start_indent = Some((row, indent));
6205                break;
6206            }
6207        }
6208        let (start_row, start_indent_size) = start_indent?;
6209
6210        let mut end_indent = (end, None);
6211        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6212            if row > end {
6213                break;
6214            }
6215            accessed_row_counter += 1;
6216            if accessed_row_counter == YIELD_INTERVAL {
6217                accessed_row_counter = 0;
6218                yield_now().await;
6219            }
6220            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6221                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6222                break;
6223            }
6224        }
6225        let (end_row, end_indent_size) = end_indent;
6226
6227        let indent = if let Some(end_indent_size) = end_indent_size {
6228            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6229                start_indent_size
6230            } else {
6231                end_indent_size
6232            }
6233        } else {
6234            start_indent_size
6235        };
6236
6237        Some((start_row..end_row, indent))
6238    }
6239
6240    pub fn indent_guides_in_range<T: ToPoint>(
6241        &self,
6242        range: Range<T>,
6243        ignore_disabled_for_language: bool,
6244        cx: &App,
6245    ) -> impl Iterator<Item = IndentGuide> {
6246        let range = range.start.to_point(self)..range.end.to_point(self);
6247        let start_row = MultiBufferRow(range.start.row);
6248        let end_row = MultiBufferRow(range.end.row);
6249
6250        let mut row_indents = self.line_indents(start_row, |buffer| {
6251            let settings =
6252                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6253            settings.indent_guides.enabled || ignore_disabled_for_language
6254        });
6255
6256        let mut result = Vec::new();
6257        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6258
6259        let mut prev_settings = None;
6260        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6261            if first_row > end_row {
6262                break;
6263            }
6264            let current_depth = indent_stack.len() as u32;
6265
6266            // Avoid retrieving the language settings repeatedly for every buffer row.
6267            if let Some((prev_buffer_id, _)) = &prev_settings
6268                && prev_buffer_id != &buffer.remote_id()
6269            {
6270                prev_settings.take();
6271            }
6272            let settings = &prev_settings
6273                .get_or_insert_with(|| {
6274                    (
6275                        buffer.remote_id(),
6276                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6277                    )
6278                })
6279                .1;
6280            let tab_size = settings.tab_size.get();
6281
6282            // When encountering empty, continue until found useful line indent
6283            // then add to the indent stack with the depth found
6284            let mut found_indent = false;
6285            let mut last_row = first_row;
6286            if line_indent.is_line_blank() {
6287                while !found_indent {
6288                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6289                        break;
6290                    };
6291                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6292                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6293                        break;
6294                    }
6295
6296                    if new_line_indent.is_line_blank() {
6297                        continue;
6298                    }
6299                    last_row = target_row.min(end_row);
6300                    line_indent = new_line_indent;
6301                    found_indent = true;
6302                    break;
6303                }
6304            } else {
6305                found_indent = true
6306            }
6307
6308            let depth = if found_indent {
6309                line_indent.len(tab_size) / tab_size
6310            } else {
6311                0
6312            };
6313
6314            match depth.cmp(&current_depth) {
6315                cmp::Ordering::Less => {
6316                    for _ in 0..(current_depth - depth) {
6317                        let mut indent = indent_stack.pop().unwrap();
6318                        if last_row != first_row {
6319                            // In this case, we landed on an empty row, had to seek forward,
6320                            // and discovered that the indent we where on is ending.
6321                            // This means that the last display row must
6322                            // be on line that ends this indent range, so we
6323                            // should display the range up to the first non-empty line
6324                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6325                        }
6326
6327                        result.push(indent)
6328                    }
6329                }
6330                cmp::Ordering::Greater => {
6331                    for next_depth in current_depth..depth {
6332                        indent_stack.push(IndentGuide {
6333                            buffer_id: buffer.remote_id(),
6334                            start_row: first_row,
6335                            end_row: last_row,
6336                            depth: next_depth,
6337                            tab_size,
6338                            settings: settings.indent_guides.clone(),
6339                        });
6340                    }
6341                }
6342                _ => {}
6343            }
6344
6345            for indent in indent_stack.iter_mut() {
6346                indent.end_row = last_row;
6347            }
6348        }
6349
6350        result.extend(indent_stack);
6351        result.into_iter()
6352    }
6353
6354    pub fn trailing_excerpt_update_count(&self) -> usize {
6355        self.trailing_excerpt_update_count
6356    }
6357
6358    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6359        self.point_to_buffer_offset(point)
6360            .and_then(|(buffer, _)| buffer.file())
6361    }
6362
6363    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6364        self.point_to_buffer_offset(offset)
6365            .and_then(|(buffer, offset)| buffer.language_at(offset))
6366    }
6367
6368    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6369        self.excerpts
6370            .first()
6371            .map(|excerpt| &excerpt.buffer)
6372            .map(|buffer| {
6373                language_settings(
6374                    buffer.language().map(|language| language.name()),
6375                    buffer.file(),
6376                    cx,
6377                )
6378            })
6379            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6380    }
6381
6382    pub fn language_settings_at<'a, T: ToOffset>(
6383        &'a self,
6384        point: T,
6385        cx: &'a App,
6386    ) -> Cow<'a, LanguageSettings> {
6387        let mut language = None;
6388        let mut file = None;
6389        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6390            language = buffer.language_at(offset);
6391            file = buffer.file();
6392        }
6393        language_settings(language.map(|l| l.name()), file, cx)
6394    }
6395
6396    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6397        self.point_to_buffer_offset(point)
6398            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6399    }
6400
6401    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6402        self.point_to_buffer_offset(point)
6403            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6404            .unwrap_or_default()
6405    }
6406
6407    pub fn language_indent_size_at<T: ToOffset>(
6408        &self,
6409        position: T,
6410        cx: &App,
6411    ) -> Option<IndentSize> {
6412        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6413        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6414    }
6415
6416    pub fn is_dirty(&self) -> bool {
6417        self.is_dirty
6418    }
6419
6420    pub fn has_deleted_file(&self) -> bool {
6421        self.has_deleted_file
6422    }
6423
6424    pub fn has_conflict(&self) -> bool {
6425        self.has_conflict
6426    }
6427
6428    pub fn has_diagnostics(&self) -> bool {
6429        self.excerpts
6430            .iter()
6431            .any(|excerpt| excerpt.buffer.has_diagnostics())
6432    }
6433
6434    pub fn diagnostic_group(
6435        &self,
6436        buffer_id: BufferId,
6437        group_id: usize,
6438    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6439        self.lift_buffer_metadata::<Point, _, _>(
6440            Point::zero()..self.max_point(),
6441            move |buffer, range| {
6442                if buffer.remote_id() != buffer_id {
6443                    return None;
6444                };
6445                Some(
6446                    buffer
6447                        .diagnostics_in_range(range, false)
6448                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6449                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6450                )
6451            },
6452        )
6453        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6454    }
6455
6456    pub fn diagnostics_in_range<'a, MBD>(
6457        &'a self,
6458        range: Range<MBD>,
6459    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6460    where
6461        MBD::TextDimension: 'a
6462            + text::ToOffset
6463            + text::FromAnchor
6464            + Sub<Output = MBD::TextDimension>
6465            + fmt::Debug
6466            + ops::Add<Output = MBD::TextDimension>
6467            + ops::AddAssign
6468            + Ord,
6469        MBD: MultiBufferDimension
6470            + Ord
6471            + Sub<Output = MBD::TextDimension>
6472            + ops::Add<MBD::TextDimension, Output = MBD>
6473            + ops::AddAssign<MBD::TextDimension>
6474            + 'a,
6475    {
6476        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6477            Some(
6478                buffer
6479                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6480                    .map(|entry| (entry.range, entry.diagnostic)),
6481            )
6482        })
6483        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6484    }
6485
6486    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6487        &'a self,
6488        range: Range<MBD>,
6489    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6490    where
6491        MBD: MultiBufferDimension
6492            + Ord
6493            + Sub<Output = MBD::TextDimension>
6494            + ops::Add<MBD::TextDimension, Output = MBD>
6495            + ops::AddAssign<MBD::TextDimension>,
6496        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6497            + ops::Add<Output = MBD::TextDimension>
6498            + text::ToOffset
6499            + text::FromAnchor
6500            + AddAssign<MBD::TextDimension>
6501            + Ord,
6502    {
6503        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6504            Some(
6505                buffer
6506                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6507                    .map(|entry| (entry.range, entry.diagnostic)),
6508            )
6509        })
6510        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6511    }
6512
6513    pub fn syntax_ancestor<T: ToOffset>(
6514        &self,
6515        range: Range<T>,
6516    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6517        let range = range.start.to_offset(self)..range.end.to_offset(self);
6518        let mut excerpt = self.excerpt_containing(range.clone())?;
6519        let node = excerpt
6520            .buffer()
6521            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6522        let node_range = node.byte_range();
6523        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6524        if !excerpt.contains_buffer_range(node_range.clone()) {
6525            return None;
6526        };
6527        Some((node, excerpt.map_range_from_buffer(node_range)))
6528    }
6529
6530    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6531        let (excerpt_id, _, buffer) = self.as_singleton()?;
6532        let outline = buffer.outline(theme);
6533        Some(Outline::new(
6534            outline
6535                .items
6536                .into_iter()
6537                .flat_map(|item| {
6538                    Some(OutlineItem {
6539                        depth: item.depth,
6540                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6541                        source_range_for_text: self
6542                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6543                        text: item.text,
6544                        highlight_ranges: item.highlight_ranges,
6545                        name_ranges: item.name_ranges,
6546                        body_range: item.body_range.and_then(|body_range| {
6547                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6548                        }),
6549                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6550                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6551                        }),
6552                    })
6553                })
6554                .collect(),
6555        ))
6556    }
6557
6558    pub fn symbols_containing<T: ToOffset>(
6559        &self,
6560        offset: T,
6561        theme: Option<&SyntaxTheme>,
6562    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6563        let anchor = self.anchor_before(offset);
6564        let excerpt @ &Excerpt {
6565            id: excerpt_id,
6566            buffer_id,
6567            ref buffer,
6568            ..
6569        } = self.excerpt(anchor.excerpt_id)?;
6570        if cfg!(debug_assertions) {
6571            match anchor.text_anchor.buffer_id {
6572                // we clearly are hitting this according to sentry, but in what situations can this occur?
6573                Some(anchor_buffer_id) => {
6574                    assert_eq!(
6575                        anchor_buffer_id, buffer_id,
6576                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6577                    )
6578                }
6579                None => assert!(anchor.is_max()),
6580            }
6581        };
6582        Some((
6583            buffer_id,
6584            buffer
6585                .symbols_containing(anchor.text_anchor, theme)
6586                .into_iter()
6587                .flat_map(|item| {
6588                    Some(OutlineItem {
6589                        depth: item.depth,
6590                        source_range_for_text: Anchor::range_in_buffer(
6591                            excerpt_id,
6592                            item.source_range_for_text,
6593                        ),
6594                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6595                        text: item.text,
6596                        highlight_ranges: item.highlight_ranges,
6597                        name_ranges: item.name_ranges,
6598                        body_range: item
6599                            .body_range
6600                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6601                        annotation_range: item
6602                            .annotation_range
6603                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6604                    })
6605                })
6606                .collect(),
6607        ))
6608    }
6609
6610    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6611        if id == ExcerptId::min() {
6612            Locator::min_ref()
6613        } else if id == ExcerptId::max() {
6614            Locator::max_ref()
6615        } else {
6616            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6617            if let Some(entry) = item
6618                && entry.id == id
6619            {
6620                return &entry.locator;
6621            }
6622            panic!("invalid excerpt id {id:?}")
6623        }
6624    }
6625
6626    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6627    fn excerpt_locators_for_ids(
6628        &self,
6629        ids: impl IntoIterator<Item = ExcerptId>,
6630    ) -> SmallVec<[Locator; 1]> {
6631        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6632        sorted_ids.sort_unstable();
6633        sorted_ids.dedup();
6634        let mut locators = SmallVec::new();
6635
6636        while sorted_ids.last() == Some(&ExcerptId::max()) {
6637            sorted_ids.pop();
6638            locators.push(Locator::max());
6639        }
6640
6641        let mut sorted_ids = sorted_ids.into_iter().peekable();
6642        locators.extend(
6643            sorted_ids
6644                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6645                .map(|_| Locator::min()),
6646        );
6647
6648        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6649        for id in sorted_ids {
6650            if cursor.seek_forward(&id, Bias::Left) {
6651                locators.push(cursor.item().unwrap().locator.clone());
6652            } else {
6653                panic!("invalid excerpt id {:?}", id);
6654            }
6655        }
6656
6657        locators.sort_unstable();
6658        locators
6659    }
6660
6661    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6662        Some(self.excerpt(excerpt_id)?.buffer_id)
6663    }
6664
6665    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6666        Some(&self.excerpt(excerpt_id)?.buffer)
6667    }
6668
6669    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6670        let mut cursor = self
6671            .excerpts
6672            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6673        let locator = self.excerpt_locator_for_id(excerpt_id);
6674        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6675        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6676            sought_exact = true;
6677            cursor.prev();
6678        } else if excerpt_id == ExcerptId::min() {
6679            sought_exact = true;
6680        }
6681        if sought_exact {
6682            let start = cursor.start().1;
6683            let end = cursor.end().1;
6684            let mut diff_transforms = self
6685                .diff_transforms
6686                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6687            diff_transforms.seek(&start, Bias::Left);
6688            let overshoot = start - diff_transforms.start().0;
6689            let start = diff_transforms.start().1 + overshoot;
6690            diff_transforms.seek(&end, Bias::Right);
6691            let overshoot = end - diff_transforms.start().0;
6692            let end = diff_transforms.start().1 + overshoot;
6693            Some(start.0..end.0)
6694        } else {
6695            None
6696        }
6697    }
6698
6699    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6700    /// to have the latest excerpt id for the one passed in and will also remap
6701    /// `ExcerptId::max()` to the corresponding excertp ID.
6702    ///
6703    /// Callers of this function should generally use the resulting excerpt's `id` field
6704    /// afterwards.
6705    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6706        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6707        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6708        let locator = self.excerpt_locator_for_id(excerpt_id);
6709        cursor.seek(&Some(locator), Bias::Left);
6710        if let Some(excerpt) = cursor.item()
6711            && excerpt.id == excerpt_id
6712        {
6713            return Some(excerpt);
6714        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6715            cursor.prev();
6716            return cursor.item();
6717        }
6718        None
6719    }
6720
6721    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6722    pub fn excerpt_containing<T: ToOffset>(
6723        &self,
6724        range: Range<T>,
6725    ) -> Option<MultiBufferExcerpt<'_>> {
6726        let range = range.start.to_offset(self)..range.end.to_offset(self);
6727        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6728        cursor.seek(&range.start);
6729
6730        let start_excerpt = cursor.excerpt()?;
6731        if range.end != range.start {
6732            cursor.seek_forward(&range.end);
6733            if cursor.excerpt()?.id != start_excerpt.id {
6734                return None;
6735            }
6736        }
6737
6738        cursor.seek_to_start_of_current_excerpt();
6739        let region = cursor.region()?;
6740        let offset = region.range.start;
6741        let buffer_offset = start_excerpt.buffer_start_offset();
6742        let excerpt_offset = *cursor.excerpts.start();
6743        Some(MultiBufferExcerpt {
6744            diff_transforms: cursor.diff_transforms,
6745            excerpt: start_excerpt,
6746            offset,
6747            buffer_offset,
6748            excerpt_offset,
6749        })
6750    }
6751
6752    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6753        if let Some(id) = anchor.text_anchor.buffer_id {
6754            return Some(id);
6755        }
6756        let excerpt = self.excerpt_containing(anchor..anchor)?;
6757        Some(excerpt.buffer_id())
6758    }
6759
6760    pub fn selections_in_range<'a>(
6761        &'a self,
6762        range: &'a Range<Anchor>,
6763        include_local: bool,
6764    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6765        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6766        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6767        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6768        cursor.seek(start_locator, Bias::Left);
6769        cursor
6770            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6771            .flat_map(move |excerpt| {
6772                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6773                if excerpt.id == range.start.excerpt_id {
6774                    query_range.start = range.start.text_anchor;
6775                }
6776                if excerpt.id == range.end.excerpt_id {
6777                    query_range.end = range.end.text_anchor;
6778                }
6779
6780                excerpt
6781                    .buffer
6782                    .selections_in_range(query_range, include_local)
6783                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6784                        selections.map(move |selection| {
6785                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6786                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6787                            if range.start.cmp(&start, self).is_gt() {
6788                                start = range.start;
6789                            }
6790                            if range.end.cmp(&end, self).is_lt() {
6791                                end = range.end;
6792                            }
6793
6794                            (
6795                                replica_id,
6796                                line_mode,
6797                                cursor_shape,
6798                                Selection {
6799                                    id: selection.id,
6800                                    start,
6801                                    end,
6802                                    reversed: selection.reversed,
6803                                    goal: selection.goal,
6804                                },
6805                            )
6806                        })
6807                    })
6808            })
6809    }
6810
6811    pub fn show_headers(&self) -> bool {
6812        self.show_headers
6813    }
6814
6815    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6816        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6817    }
6818
6819    pub fn all_diff_hunks_expanded(&self) -> bool {
6820        self.all_diff_hunks_expanded
6821    }
6822
6823    /// Visually annotates a position or range with the `Debug` representation of a value. The
6824    /// callsite of this function is used as a key - previous annotations will be removed.
6825    #[cfg(debug_assertions)]
6826    #[track_caller]
6827    pub fn debug<V, R>(&self, ranges: &R, value: V)
6828    where
6829        R: debug::ToMultiBufferDebugRanges,
6830        V: std::fmt::Debug,
6831    {
6832        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6833    }
6834
6835    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6836    /// debug annotations with the same key will be removed. The key is also used to determine the
6837    /// annotation's color.
6838    #[cfg(debug_assertions)]
6839    #[track_caller]
6840    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6841    where
6842        K: std::hash::Hash + 'static,
6843        R: debug::ToMultiBufferDebugRanges,
6844        V: std::fmt::Debug,
6845    {
6846        let text_ranges = ranges
6847            .to_multi_buffer_debug_ranges(self)
6848            .into_iter()
6849            .flat_map(|range| {
6850                self.range_to_buffer_ranges(range.start..=range.end)
6851                    .into_iter()
6852                    .map(|(buffer, range, _excerpt_id)| {
6853                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6854                    })
6855            })
6856            .collect();
6857        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6858            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6859        });
6860    }
6861
6862    fn excerpt_edits_for_diff_change(
6863        &self,
6864        buffer_state: &BufferState,
6865        diff_change_range: Range<usize>,
6866    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6867        let mut excerpt_edits = Vec::new();
6868        for locator in &buffer_state.excerpts {
6869            let mut cursor = self
6870                .excerpts
6871                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6872            cursor.seek_forward(&Some(locator), Bias::Left);
6873            if let Some(excerpt) = cursor.item()
6874                && excerpt.locator == *locator
6875            {
6876                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6877                if diff_change_range.end < excerpt_buffer_range.start
6878                    || diff_change_range.start > excerpt_buffer_range.end
6879                {
6880                    continue;
6881                }
6882                let excerpt_start = cursor.start().1;
6883                let excerpt_len = excerpt.text_summary.len;
6884                let diff_change_start_in_excerpt = diff_change_range
6885                    .start
6886                    .saturating_sub(excerpt_buffer_range.start);
6887                let diff_change_end_in_excerpt = diff_change_range
6888                    .end
6889                    .saturating_sub(excerpt_buffer_range.start);
6890                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6891                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6892                excerpt_edits.push(Edit {
6893                    old: edit_start..edit_end,
6894                    new: edit_start..edit_end,
6895                });
6896            }
6897        }
6898        excerpt_edits
6899    }
6900}
6901
6902#[cfg(any(test, feature = "test-support"))]
6903impl MultiBufferSnapshot {
6904    pub fn random_byte_range(
6905        &self,
6906        start_offset: MultiBufferOffset,
6907        rng: &mut impl rand::Rng,
6908    ) -> Range<MultiBufferOffset> {
6909        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6910        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6911        start..end
6912    }
6913
6914    #[cfg(any(test, feature = "test-support"))]
6915    fn check_invariants(&self) {
6916        let excerpts = self.excerpts.items(());
6917        let excerpt_ids = self.excerpt_ids.items(());
6918
6919        for (ix, excerpt) in excerpts.iter().enumerate() {
6920            if ix == 0 {
6921                if excerpt.locator <= Locator::min() {
6922                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6923                }
6924            } else if excerpt.locator <= excerpts[ix - 1].locator {
6925                panic!("excerpts are out-of-order: {:?}", excerpts);
6926            }
6927        }
6928
6929        for (ix, entry) in excerpt_ids.iter().enumerate() {
6930            if ix == 0 {
6931                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6932                    panic!("invalid first excerpt id {:?}", entry.id);
6933                }
6934            } else if entry.id <= excerpt_ids[ix - 1].id {
6935                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6936            }
6937        }
6938
6939        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6940            panic!(
6941                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6942                self.excerpts.summary().text,
6943                self.diff_transforms.summary().input,
6944                self.diff_transforms.items(()),
6945            );
6946        }
6947
6948        let mut prev_transform: Option<&DiffTransform> = None;
6949        for item in self.diff_transforms.iter() {
6950            if let DiffTransform::BufferContent {
6951                summary,
6952                inserted_hunk_info,
6953            } = item
6954            {
6955                if let Some(DiffTransform::BufferContent {
6956                    inserted_hunk_info: prev_inserted_hunk_info,
6957                    ..
6958                }) = prev_transform
6959                    && *inserted_hunk_info == *prev_inserted_hunk_info
6960                {
6961                    panic!(
6962                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6963                        self.diff_transforms.items(())
6964                    );
6965                }
6966                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6967                    panic!("empty buffer content transform");
6968                }
6969            }
6970            prev_transform = Some(item);
6971        }
6972    }
6973}
6974
6975impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6976where
6977    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6978    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6979{
6980    #[instrument(skip_all)]
6981    fn seek(&mut self, position: &MBD) {
6982        let position = OutputDimension(*position);
6983        self.cached_region.take();
6984        self.diff_transforms.seek(&position, Bias::Right);
6985        if self.diff_transforms.item().is_none()
6986            && self.diff_transforms.start().output_dimension == position
6987        {
6988            self.diff_transforms.prev();
6989        }
6990
6991        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6992        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6993            let overshoot = position - self.diff_transforms.start().output_dimension;
6994            excerpt_position += overshoot;
6995        }
6996
6997        self.excerpts.seek(&excerpt_position, Bias::Right);
6998        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6999            self.excerpts.prev();
7000        }
7001    }
7002
7003    fn seek_forward(&mut self, position: &MBD) {
7004        let position = OutputDimension(*position);
7005        self.cached_region.take();
7006        self.diff_transforms.seek_forward(&position, Bias::Right);
7007        if self.diff_transforms.item().is_none()
7008            && self.diff_transforms.start().output_dimension == position
7009        {
7010            self.diff_transforms.prev();
7011        }
7012
7013        let overshoot = position - self.diff_transforms.start().output_dimension;
7014        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7015        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7016            excerpt_position += overshoot;
7017        }
7018
7019        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7020        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7021            self.excerpts.prev();
7022        }
7023    }
7024
7025    fn next_excerpt(&mut self) {
7026        self.excerpts.next();
7027        self.seek_to_start_of_current_excerpt();
7028    }
7029
7030    fn prev_excerpt(&mut self) {
7031        self.excerpts.prev();
7032        self.seek_to_start_of_current_excerpt();
7033    }
7034
7035    fn seek_to_start_of_current_excerpt(&mut self) {
7036        self.cached_region.take();
7037
7038        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7039            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7040            && self.diff_transforms.next_item().is_some()
7041        {
7042            self.diff_transforms.next();
7043        }
7044    }
7045
7046    fn next_excerpt_forwards(&mut self) {
7047        self.excerpts.next();
7048        self.seek_to_start_of_current_excerpt_forward();
7049    }
7050
7051    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7052        self.cached_region.take();
7053
7054        if self
7055            .diff_transforms
7056            .seek_forward(self.excerpts.start(), Bias::Left)
7057            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7058            && self.diff_transforms.next_item().is_some()
7059        {
7060            self.diff_transforms.next();
7061        }
7062    }
7063
7064    fn next(&mut self) {
7065        self.cached_region.take();
7066        match self
7067            .diff_transforms
7068            .end()
7069            .excerpt_dimension
7070            .cmp(&self.excerpts.end())
7071        {
7072            cmp::Ordering::Less => self.diff_transforms.next(),
7073            cmp::Ordering::Greater => self.excerpts.next(),
7074            cmp::Ordering::Equal => {
7075                self.diff_transforms.next();
7076                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7077                    || self.diff_transforms.item().is_none()
7078                {
7079                    self.excerpts.next();
7080                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7081                    self.diff_transforms.item()
7082                    && self
7083                        .excerpts
7084                        .item()
7085                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7086                {
7087                    self.excerpts.next();
7088                }
7089            }
7090        }
7091    }
7092
7093    fn prev(&mut self) {
7094        self.cached_region.take();
7095        match self
7096            .diff_transforms
7097            .start()
7098            .excerpt_dimension
7099            .cmp(self.excerpts.start())
7100        {
7101            cmp::Ordering::Less => self.excerpts.prev(),
7102            cmp::Ordering::Greater => self.diff_transforms.prev(),
7103            cmp::Ordering::Equal => {
7104                self.diff_transforms.prev();
7105                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7106                    || self.diff_transforms.item().is_none()
7107                {
7108                    self.excerpts.prev();
7109                }
7110            }
7111        }
7112    }
7113
7114    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7115        self.cached_region
7116            .get_or_init(|| self.build_region())
7117            .as_ref()
7118    }
7119
7120    fn is_at_start_of_excerpt(&mut self) -> bool {
7121        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7122            return false;
7123        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7124            return true;
7125        }
7126
7127        self.diff_transforms.prev();
7128        let prev_transform = self.diff_transforms.item();
7129        self.diff_transforms.next();
7130
7131        prev_transform.is_none_or(|next_transform| {
7132            matches!(next_transform, DiffTransform::BufferContent { .. })
7133        })
7134    }
7135
7136    fn is_at_end_of_excerpt(&self) -> bool {
7137        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7138            return false;
7139        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7140            || self.diff_transforms.item().is_none()
7141        {
7142            return true;
7143        }
7144
7145        let next_transform = self.diff_transforms.next_item();
7146        next_transform.is_none_or(|next_transform| match next_transform {
7147            DiffTransform::BufferContent { .. } => true,
7148            DiffTransform::DeletedHunk { hunk_info, .. } => self
7149                .excerpts
7150                .item()
7151                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7152        })
7153    }
7154
7155    fn main_buffer_position(&self) -> Option<BD> {
7156        let excerpt = self.excerpts.item()?;
7157        let buffer = &excerpt.buffer;
7158        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7159        let mut buffer_start = buffer_context_start;
7160        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7161        buffer_start += overshoot;
7162        Some(buffer_start)
7163    }
7164
7165    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7166        let excerpt = self.excerpts.item()?;
7167        match self.diff_transforms.item()? {
7168            DiffTransform::DeletedHunk {
7169                buffer_id,
7170                base_text_byte_range,
7171                has_trailing_newline,
7172                hunk_info,
7173                ..
7174            } => {
7175                let diff = self.diffs.get(buffer_id)?;
7176                let buffer = diff.base_text();
7177                let mut rope_cursor = buffer.as_rope().cursor(0);
7178                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7179                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7180                let mut buffer_end = buffer_start;
7181                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7182                let start = self.diff_transforms.start().output_dimension.0;
7183                let end = self.diff_transforms.end().output_dimension.0;
7184                Some(MultiBufferRegion {
7185                    buffer,
7186                    excerpt,
7187                    has_trailing_newline: *has_trailing_newline,
7188                    is_main_buffer: false,
7189                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7190                        hunk_info.hunk_secondary_status,
7191                    )),
7192                    buffer_range: buffer_start..buffer_end,
7193                    range: start..end,
7194                })
7195            }
7196            DiffTransform::BufferContent {
7197                inserted_hunk_info, ..
7198            } => {
7199                let buffer = &excerpt.buffer;
7200                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7201
7202                let mut start = self.diff_transforms.start().output_dimension.0;
7203                let mut buffer_start = buffer_context_start;
7204                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7205                    let overshoot =
7206                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7207                    start += overshoot;
7208                } else {
7209                    let overshoot =
7210                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7211                    buffer_start += overshoot;
7212                }
7213
7214                let mut end;
7215                let mut buffer_end;
7216                let has_trailing_newline;
7217                let transform_end = self.diff_transforms.end();
7218                if transform_end.excerpt_dimension < self.excerpts.end() {
7219                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7220                    end = transform_end.output_dimension.0;
7221                    buffer_end = buffer_context_start;
7222                    buffer_end += overshoot;
7223                    has_trailing_newline = false;
7224                } else {
7225                    let overshoot =
7226                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7227                    end = self.diff_transforms.start().output_dimension.0;
7228                    end += overshoot;
7229                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7230                    has_trailing_newline = excerpt.has_trailing_newline;
7231                };
7232
7233                let diff_hunk_status = inserted_hunk_info.map(|info| {
7234                    if info.is_logically_deleted {
7235                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7236                    } else {
7237                        DiffHunkStatus::added(info.hunk_secondary_status)
7238                    }
7239                });
7240
7241                Some(MultiBufferRegion {
7242                    buffer,
7243                    excerpt,
7244                    has_trailing_newline,
7245                    is_main_buffer: true,
7246                    diff_hunk_status,
7247                    buffer_range: buffer_start..buffer_end,
7248                    range: start..end,
7249                })
7250            }
7251        }
7252    }
7253
7254    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7255        let excerpt = self.excerpts.item()?;
7256        match self.diff_transforms.item()? {
7257            &DiffTransform::DeletedHunk { .. } => {
7258                let start = self.diff_transforms.start().output_dimension.0;
7259                let end = self.diff_transforms.end().output_dimension.0;
7260                Some((excerpt, start..end))
7261            }
7262            DiffTransform::BufferContent { .. } => {
7263                let mut start = self.diff_transforms.start().output_dimension.0;
7264                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7265                    let overshoot =
7266                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7267                    start += overshoot;
7268                }
7269
7270                let mut end;
7271                let transform_end = self.diff_transforms.end();
7272                if transform_end.excerpt_dimension < self.excerpts.end() {
7273                    end = transform_end.output_dimension.0;
7274                } else {
7275                    let overshoot =
7276                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7277                    end = self.diff_transforms.start().output_dimension.0;
7278                    end += overshoot;
7279                };
7280
7281                Some((excerpt, start..end))
7282            }
7283        }
7284    }
7285
7286    fn excerpt(&self) -> Option<&'a Excerpt> {
7287        self.excerpts.item()
7288    }
7289}
7290
7291impl Excerpt {
7292    fn new(
7293        id: ExcerptId,
7294        locator: Locator,
7295        buffer_id: BufferId,
7296        buffer: Arc<BufferSnapshot>,
7297        range: ExcerptRange<text::Anchor>,
7298        has_trailing_newline: bool,
7299    ) -> Self {
7300        Excerpt {
7301            id,
7302            locator,
7303            max_buffer_row: range.context.end.to_point(&buffer).row,
7304            text_summary: buffer
7305                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7306            buffer_id,
7307            buffer,
7308            range,
7309            has_trailing_newline,
7310        }
7311    }
7312
7313    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7314        let content_start = self.range.context.start.to_offset(&self.buffer);
7315        let chunks_start = content_start + range.start;
7316        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7317
7318        let has_footer = self.has_trailing_newline
7319            && range.start <= self.text_summary.len
7320            && range.end > self.text_summary.len;
7321
7322        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7323
7324        ExcerptChunks {
7325            excerpt_id: self.id,
7326            content_chunks,
7327            has_footer,
7328        }
7329    }
7330
7331    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7332        let content_start = self.range.context.start.to_offset(&self.buffer);
7333        let chunks_start = content_start + range.start;
7334        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7335        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7336        excerpt_chunks.has_footer = self.has_trailing_newline
7337            && range.start <= self.text_summary.len
7338            && range.end > self.text_summary.len;
7339    }
7340
7341    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7342        if text_anchor
7343            .cmp(&self.range.context.start, &self.buffer)
7344            .is_lt()
7345        {
7346            self.range.context.start
7347        } else if text_anchor
7348            .cmp(&self.range.context.end, &self.buffer)
7349            .is_gt()
7350        {
7351            self.range.context.end
7352        } else {
7353            text_anchor
7354        }
7355    }
7356
7357    fn contains(&self, anchor: &Anchor) -> bool {
7358        (anchor.text_anchor.buffer_id == None
7359            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7360            && self
7361                .range
7362                .context
7363                .start
7364                .cmp(&anchor.text_anchor, &self.buffer)
7365                .is_le()
7366            && self
7367                .range
7368                .context
7369                .end
7370                .cmp(&anchor.text_anchor, &self.buffer)
7371                .is_ge()
7372    }
7373
7374    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7375    fn buffer_start_offset(&self) -> BufferOffset {
7376        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7377    }
7378
7379    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7380    fn buffer_end_offset(&self) -> BufferOffset {
7381        self.buffer_start_offset() + self.text_summary.len
7382    }
7383}
7384
7385impl<'a> MultiBufferExcerpt<'a> {
7386    pub fn id(&self) -> ExcerptId {
7387        self.excerpt.id
7388    }
7389
7390    pub fn buffer_id(&self) -> BufferId {
7391        self.excerpt.buffer_id
7392    }
7393
7394    pub fn start_anchor(&self) -> Anchor {
7395        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7396    }
7397
7398    pub fn end_anchor(&self) -> Anchor {
7399        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7400    }
7401
7402    pub fn buffer(&self) -> &'a BufferSnapshot {
7403        &self.excerpt.buffer
7404    }
7405
7406    pub fn buffer_range(&self) -> Range<BufferOffset> {
7407        self.buffer_offset
7408            ..BufferOffset(
7409                self.excerpt
7410                    .range
7411                    .context
7412                    .end
7413                    .to_offset(&self.excerpt.buffer.text),
7414            )
7415    }
7416
7417    pub fn start_offset(&self) -> MultiBufferOffset {
7418        self.offset
7419    }
7420
7421    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7422    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7423        self.map_range_to_buffer(offset..offset).start
7424    }
7425
7426    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7427    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7428        self.diff_transforms
7429            .seek(&OutputDimension(range.start), Bias::Right);
7430        let start = self.map_offset_to_buffer_internal(range.start);
7431        let end = if range.end > range.start {
7432            self.diff_transforms
7433                .seek_forward(&OutputDimension(range.end), Bias::Right);
7434            self.map_offset_to_buffer_internal(range.end)
7435        } else {
7436            start
7437        };
7438        start..end
7439    }
7440
7441    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7442        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7443        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7444            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7445        };
7446        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7447        self.buffer_offset + offset_in_excerpt
7448    }
7449
7450    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7451    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7452        self.map_range_from_buffer(buffer_offset..buffer_offset)
7453            .start
7454    }
7455
7456    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7457    pub fn map_range_from_buffer(
7458        &mut self,
7459        buffer_range: Range<BufferOffset>,
7460    ) -> Range<MultiBufferOffset> {
7461        if buffer_range.start < self.buffer_offset {
7462            log::warn!(
7463                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7464            );
7465            return self.offset..self.offset;
7466        }
7467        let overshoot = buffer_range.start - self.buffer_offset;
7468        let excerpt_offset = self.excerpt_offset + overshoot;
7469        let excerpt_seek_dim = excerpt_offset;
7470        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7471        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7472            log::warn!(
7473                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7474            );
7475            return self.offset..self.offset;
7476        }
7477        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7478        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7479
7480        let end = if buffer_range.start < buffer_range.end {
7481            let overshoot = buffer_range.end - self.buffer_offset;
7482            let excerpt_offset = self.excerpt_offset + overshoot;
7483            let excerpt_seek_dim = excerpt_offset;
7484            self.diff_transforms
7485                .seek_forward(&excerpt_seek_dim, Bias::Right);
7486            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7487            // todo(lw): Clamp end to the excerpt boundaries
7488            self.diff_transforms.start().output_dimension.0 + overshoot
7489        } else {
7490            start
7491        };
7492
7493        start..end
7494    }
7495
7496    /// Returns true if the entirety of the given range is in the buffer's excerpt
7497    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7498        range.start >= self.excerpt.buffer_start_offset()
7499            && range.end <= self.excerpt.buffer_end_offset()
7500    }
7501
7502    /// Returns true if any part of the given range is in the buffer's excerpt
7503    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7504        range.start <= self.excerpt.buffer_end_offset()
7505            && range.end >= self.excerpt.buffer_start_offset()
7506    }
7507
7508    pub fn max_buffer_row(&self) -> u32 {
7509        self.excerpt.max_buffer_row
7510    }
7511}
7512
7513impl ExcerptId {
7514    pub fn min() -> Self {
7515        Self(0)
7516    }
7517
7518    pub fn max() -> Self {
7519        Self(u32::MAX)
7520    }
7521
7522    pub fn to_proto(self) -> u64 {
7523        self.0 as _
7524    }
7525
7526    pub fn from_proto(proto: u64) -> Self {
7527        Self(proto as _)
7528    }
7529
7530    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7531        let a = snapshot.excerpt_locator_for_id(*self);
7532        let b = snapshot.excerpt_locator_for_id(*other);
7533        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7534    }
7535}
7536
7537impl From<ExcerptId> for usize {
7538    fn from(val: ExcerptId) -> Self {
7539        val.0 as usize
7540    }
7541}
7542
7543impl fmt::Debug for Excerpt {
7544    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7545        f.debug_struct("Excerpt")
7546            .field("id", &self.id)
7547            .field("locator", &self.locator)
7548            .field("buffer_id", &self.buffer_id)
7549            .field("range", &self.range)
7550            .field("text_summary", &self.text_summary)
7551            .field("has_trailing_newline", &self.has_trailing_newline)
7552            .finish()
7553    }
7554}
7555
7556impl sum_tree::Item for Excerpt {
7557    type Summary = ExcerptSummary;
7558
7559    fn summary(&self, _cx: ()) -> Self::Summary {
7560        let mut text = self.text_summary;
7561        if self.has_trailing_newline {
7562            text += TextSummary::from("\n");
7563        }
7564        ExcerptSummary {
7565            excerpt_id: self.id,
7566            excerpt_locator: self.locator.clone(),
7567            widest_line_number: self.max_buffer_row,
7568            text: text.into(),
7569        }
7570    }
7571}
7572
7573impl sum_tree::Item for ExcerptIdMapping {
7574    type Summary = ExcerptId;
7575
7576    fn summary(&self, _cx: ()) -> Self::Summary {
7577        self.id
7578    }
7579}
7580
7581impl sum_tree::KeyedItem for ExcerptIdMapping {
7582    type Key = ExcerptId;
7583
7584    fn key(&self) -> Self::Key {
7585        self.id
7586    }
7587}
7588
7589impl DiffTransform {
7590    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7591        match self {
7592            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7593            DiffTransform::BufferContent {
7594                inserted_hunk_info, ..
7595            } => *inserted_hunk_info,
7596        }
7597    }
7598}
7599
7600impl sum_tree::Item for DiffTransform {
7601    type Summary = DiffTransformSummary;
7602
7603    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7604        match self {
7605            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7606                input: *summary,
7607                output: *summary,
7608            },
7609            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7610                input: MBTextSummary::default(),
7611                output: summary.into(),
7612            },
7613        }
7614    }
7615}
7616
7617impl DiffTransformSummary {
7618    fn excerpt_len(&self) -> ExcerptOffset {
7619        ExcerptDimension(self.input.len)
7620    }
7621}
7622
7623impl sum_tree::ContextLessSummary for DiffTransformSummary {
7624    fn zero() -> Self {
7625        DiffTransformSummary {
7626            input: MBTextSummary::default(),
7627            output: MBTextSummary::default(),
7628        }
7629    }
7630
7631    fn add_summary(&mut self, other: &Self) {
7632        self.input += other.input;
7633        self.output += other.output;
7634    }
7635}
7636
7637impl sum_tree::ContextLessSummary for ExcerptId {
7638    fn zero() -> Self {
7639        Self(0)
7640    }
7641
7642    fn add_summary(&mut self, summary: &Self) {
7643        *self = cmp::max(*self, *summary);
7644    }
7645}
7646
7647impl sum_tree::ContextLessSummary for ExcerptSummary {
7648    fn zero() -> Self {
7649        Self::default()
7650    }
7651
7652    fn add_summary(&mut self, summary: &Self) {
7653        debug_assert!(
7654            summary.excerpt_locator > self.excerpt_locator
7655                || self.excerpt_locator == Locator::min(),
7656            "Excerpt locators must be in ascending order: {:?} > {:?}",
7657            summary.excerpt_locator,
7658            self.excerpt_locator
7659        );
7660        self.excerpt_locator = summary.excerpt_locator.clone();
7661        self.text += summary.text;
7662        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7663    }
7664}
7665
7666impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7667    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7668        Ord::cmp(&Some(self), cursor_location)
7669    }
7670}
7671
7672impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7673    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7674        Ord::cmp(self, &cursor_location.excerpt_locator)
7675    }
7676}
7677
7678impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7679where
7680    MBD: MultiBufferDimension + Default,
7681{
7682    fn zero(_: ()) -> Self {
7683        ExcerptDimension(MBD::default())
7684    }
7685
7686    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7687        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7688    }
7689}
7690
7691impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7692    fn zero(_cx: ()) -> Self {
7693        Default::default()
7694    }
7695
7696    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7697        *self = Some(&summary.excerpt_locator);
7698    }
7699}
7700
7701impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7702    fn zero(_cx: ()) -> Self {
7703        Default::default()
7704    }
7705
7706    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7707        *self = Some(summary.excerpt_id);
7708    }
7709}
7710
7711#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7712struct OutputDimension<T>(T);
7713
7714impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7715    fn eq(&self, other: &T) -> bool {
7716        self.0 == *other
7717    }
7718}
7719
7720impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7721    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7722        self.0.partial_cmp(other)
7723    }
7724}
7725
7726impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7727where
7728    T: ops::Sub<U, Output = R>,
7729{
7730    type Output = R;
7731
7732    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7733        self.0 - other.0
7734    }
7735}
7736
7737impl<R, T, U> ops::Add<U> for OutputDimension<T>
7738where
7739    T: ops::Add<U, Output = R>,
7740{
7741    type Output = OutputDimension<R>;
7742
7743    fn add(self, other: U) -> Self::Output {
7744        OutputDimension(self.0 + other)
7745    }
7746}
7747
7748impl<T, U> AddAssign<U> for OutputDimension<T>
7749where
7750    T: AddAssign<U>,
7751{
7752    fn add_assign(&mut self, other: U) {
7753        self.0 += other;
7754    }
7755}
7756
7757impl<T, U> SubAssign<U> for OutputDimension<T>
7758where
7759    T: SubAssign<U>,
7760{
7761    fn sub_assign(&mut self, other: U) {
7762        self.0 -= other;
7763    }
7764}
7765
7766#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7767struct ExcerptDimension<T>(T);
7768
7769impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7770    fn eq(&self, other: &T) -> bool {
7771        self.0 == *other
7772    }
7773}
7774
7775impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7776    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7777        self.0.partial_cmp(other)
7778    }
7779}
7780
7781impl ExcerptOffset {
7782    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7783        self.0.saturating_sub(other.0)
7784    }
7785}
7786
7787impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7788where
7789    T: ops::Sub<U, Output = R>,
7790{
7791    type Output = R;
7792
7793    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7794        self.0 - other.0
7795    }
7796}
7797
7798impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7799where
7800    T: ops::Add<U, Output = R>,
7801{
7802    type Output = ExcerptDimension<R>;
7803
7804    fn add(self, other: U) -> Self::Output {
7805        ExcerptDimension(self.0 + other)
7806    }
7807}
7808
7809impl<T, U> AddAssign<U> for ExcerptDimension<T>
7810where
7811    T: AddAssign<U>,
7812{
7813    fn add_assign(&mut self, other: U) {
7814        self.0 += other;
7815    }
7816}
7817
7818impl<T, U> SubAssign<U> for ExcerptDimension<T>
7819where
7820    T: SubAssign<U>,
7821{
7822    fn sub_assign(&mut self, other: U) {
7823        self.0 -= other;
7824    }
7825}
7826
7827impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7828    fn zero(_: ()) -> Self {
7829        MultiBufferOffset::ZERO
7830    }
7831
7832    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7833        *self += summary.output.len;
7834    }
7835}
7836
7837impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7838    for ExcerptDimension<MBD>
7839where
7840    MBD: MultiBufferDimension + Ord,
7841{
7842    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7843        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7844    }
7845}
7846
7847impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7848    for ExcerptDimension<MBD>
7849where
7850    MBD: MultiBufferDimension + Ord,
7851{
7852    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7853        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7854    }
7855}
7856
7857impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7858    for ExcerptDimension<MBD>
7859{
7860    fn zero(_: ()) -> Self {
7861        ExcerptDimension(MBD::default())
7862    }
7863
7864    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7865        self.0.add_mb_text_summary(&summary.input)
7866    }
7867}
7868
7869impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7870    for OutputDimension<MBD>
7871where
7872    MBD: MultiBufferDimension + Ord,
7873{
7874    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7875        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7876    }
7877}
7878
7879impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7880    for OutputDimension<MBD>
7881{
7882    fn zero(_: ()) -> Self {
7883        OutputDimension(MBD::default())
7884    }
7885
7886    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7887        self.0.add_mb_text_summary(&summary.output)
7888    }
7889}
7890
7891impl MultiBufferRows<'_> {
7892    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7893        self.point = Point::new(row, 0);
7894        self.cursor.seek(&self.point);
7895    }
7896}
7897
7898impl Iterator for MultiBufferRows<'_> {
7899    type Item = RowInfo;
7900
7901    fn next(&mut self) -> Option<Self::Item> {
7902        if self.is_empty && self.point.row == 0 {
7903            self.point += Point::new(1, 0);
7904            return Some(RowInfo {
7905                buffer_id: None,
7906                buffer_row: Some(0),
7907                multibuffer_row: Some(MultiBufferRow(0)),
7908                diff_status: None,
7909                expand_info: None,
7910                wrapped_buffer_row: None,
7911            });
7912        }
7913
7914        let mut region = self.cursor.region()?.clone();
7915        while self.point >= region.range.end {
7916            self.cursor.next();
7917            if let Some(next_region) = self.cursor.region() {
7918                region = next_region.clone();
7919            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7920                let multibuffer_row = MultiBufferRow(self.point.row);
7921                let last_excerpt = self
7922                    .cursor
7923                    .excerpts
7924                    .item()
7925                    .or(self.cursor.excerpts.prev_item())?;
7926                let last_row = last_excerpt
7927                    .range
7928                    .context
7929                    .end
7930                    .to_point(&last_excerpt.buffer)
7931                    .row;
7932
7933                let first_row = last_excerpt
7934                    .range
7935                    .context
7936                    .start
7937                    .to_point(&last_excerpt.buffer)
7938                    .row;
7939
7940                let expand_info = if self.is_singleton {
7941                    None
7942                } else {
7943                    let needs_expand_up = first_row == last_row
7944                        && last_row > 0
7945                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7946                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7947
7948                    if needs_expand_up && needs_expand_down {
7949                        Some(ExpandExcerptDirection::UpAndDown)
7950                    } else if needs_expand_up {
7951                        Some(ExpandExcerptDirection::Up)
7952                    } else if needs_expand_down {
7953                        Some(ExpandExcerptDirection::Down)
7954                    } else {
7955                        None
7956                    }
7957                    .map(|direction| ExpandInfo {
7958                        direction,
7959                        excerpt_id: last_excerpt.id,
7960                    })
7961                };
7962                self.point += Point::new(1, 0);
7963                return Some(RowInfo {
7964                    buffer_id: Some(last_excerpt.buffer_id),
7965                    buffer_row: Some(last_row),
7966                    multibuffer_row: Some(multibuffer_row),
7967                    diff_status: None,
7968                    wrapped_buffer_row: None,
7969                    expand_info,
7970                });
7971            } else {
7972                return None;
7973            };
7974        }
7975
7976        let overshoot = self.point - region.range.start;
7977        let buffer_point = region.buffer_range.start + overshoot;
7978        let expand_info = if self.is_singleton {
7979            None
7980        } else {
7981            let needs_expand_up = self.point.row == region.range.start.row
7982                && self.cursor.is_at_start_of_excerpt()
7983                && buffer_point.row > 0;
7984            let needs_expand_down = (region.excerpt.has_trailing_newline
7985                && self.point.row + 1 == region.range.end.row
7986                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7987                && self.cursor.is_at_end_of_excerpt()
7988                && buffer_point.row < region.buffer.max_point().row;
7989
7990            if needs_expand_up && needs_expand_down {
7991                Some(ExpandExcerptDirection::UpAndDown)
7992            } else if needs_expand_up {
7993                Some(ExpandExcerptDirection::Up)
7994            } else if needs_expand_down {
7995                Some(ExpandExcerptDirection::Down)
7996            } else {
7997                None
7998            }
7999            .map(|direction| ExpandInfo {
8000                direction,
8001                excerpt_id: region.excerpt.id,
8002            })
8003        };
8004
8005        let result = Some(RowInfo {
8006            buffer_id: Some(region.buffer.remote_id()),
8007            buffer_row: Some(buffer_point.row),
8008            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8009            diff_status: region
8010                .diff_hunk_status
8011                .filter(|_| self.point < region.range.end),
8012            expand_info,
8013            wrapped_buffer_row: None,
8014        });
8015        self.point += Point::new(1, 0);
8016        result
8017    }
8018}
8019
8020impl<'a> MultiBufferChunks<'a> {
8021    pub fn offset(&self) -> MultiBufferOffset {
8022        self.range.start
8023    }
8024
8025    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8026        self.diff_transforms.seek(&range.end, Bias::Right);
8027        let mut excerpt_end = self.diff_transforms.start().1;
8028        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8029            let overshoot = range.end - self.diff_transforms.start().0;
8030            excerpt_end += overshoot;
8031        }
8032
8033        self.diff_transforms.seek(&range.start, Bias::Right);
8034        let mut excerpt_start = self.diff_transforms.start().1;
8035        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8036            let overshoot = range.start - self.diff_transforms.start().0;
8037            excerpt_start += overshoot;
8038        }
8039
8040        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8041        self.buffer_chunk.take();
8042        self.range = range;
8043    }
8044
8045    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8046        self.excerpt_offset_range = new_range.clone();
8047        self.excerpts.seek(&new_range.start, Bias::Right);
8048        if let Some(excerpt) = self.excerpts.item() {
8049            let excerpt_start = *self.excerpts.start();
8050            if let Some(excerpt_chunks) = self
8051                .excerpt_chunks
8052                .as_mut()
8053                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8054            {
8055                excerpt.seek_chunks(
8056                    excerpt_chunks,
8057                    (self.excerpt_offset_range.start - excerpt_start)
8058                        ..(self.excerpt_offset_range.end - excerpt_start),
8059                );
8060            } else {
8061                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8062                    (self.excerpt_offset_range.start - excerpt_start)
8063                        ..(self.excerpt_offset_range.end - excerpt_start),
8064                    self.language_aware,
8065                ));
8066            }
8067        } else {
8068            self.excerpt_chunks = None;
8069        }
8070    }
8071
8072    #[ztracing::instrument(skip_all)]
8073    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8074        loop {
8075            if self.excerpt_offset_range.is_empty() {
8076                return None;
8077            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8078                self.excerpt_offset_range.start += chunk.text.len();
8079                return Some(chunk);
8080            } else {
8081                self.excerpts.next();
8082                let excerpt = self.excerpts.item()?;
8083                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8084                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8085                    self.language_aware,
8086                ));
8087            }
8088        }
8089    }
8090}
8091
8092impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8093    type Item = &'a str;
8094
8095    fn next(&mut self) -> Option<Self::Item> {
8096        let mut region = self.cursor.region()?;
8097        if self.offset == region.range.start {
8098            self.cursor.prev();
8099            region = self.cursor.region()?;
8100            let start_overshoot = self.start.saturating_sub(region.range.start);
8101            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8102                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8103            ));
8104        }
8105
8106        if self.offset == region.range.end && region.has_trailing_newline {
8107            self.offset -= 1;
8108            Some("\n")
8109        } else {
8110            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8111            self.offset -= chunk.len();
8112            Some(chunk)
8113        }
8114    }
8115}
8116
8117impl<'a> Iterator for MultiBufferChunks<'a> {
8118    type Item = Chunk<'a>;
8119
8120    #[ztracing::instrument(skip_all)]
8121    fn next(&mut self) -> Option<Chunk<'a>> {
8122        if self.range.start >= self.range.end {
8123            return None;
8124        }
8125        if self.range.start == self.diff_transforms.end().0 {
8126            self.diff_transforms.next();
8127        }
8128
8129        let diff_transform_start = self.diff_transforms.start().0;
8130        let diff_transform_end = self.diff_transforms.end().0;
8131        debug_assert!(
8132            self.range.start < diff_transform_end,
8133            "{:?} < {:?} of ({1:?}..{2:?})",
8134            self.range.start,
8135            diff_transform_end,
8136            diff_transform_start
8137        );
8138
8139        let diff_transform = self.diff_transforms.item()?;
8140        match diff_transform {
8141            DiffTransform::BufferContent { .. } => {
8142                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8143                    chunk
8144                } else {
8145                    let chunk = self.next_excerpt_chunk().unwrap();
8146                    self.buffer_chunk.insert(chunk)
8147                };
8148
8149                let chunk_end = self.range.start + chunk.text.len();
8150                let diff_transform_end = diff_transform_end.min(self.range.end);
8151
8152                if diff_transform_end < chunk_end {
8153                    let split_idx = diff_transform_end - self.range.start;
8154                    let (before, after) = chunk.text.split_at(split_idx);
8155                    self.range.start = diff_transform_end;
8156                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8157                    let chars = chunk.chars & mask;
8158                    let tabs = chunk.tabs & mask;
8159
8160                    chunk.text = after;
8161                    chunk.chars = chunk.chars >> split_idx;
8162                    chunk.tabs = chunk.tabs >> split_idx;
8163
8164                    Some(Chunk {
8165                        text: before,
8166                        chars,
8167                        tabs,
8168                        ..chunk.clone()
8169                    })
8170                } else {
8171                    self.range.start = chunk_end;
8172                    self.buffer_chunk.take()
8173                }
8174            }
8175            DiffTransform::DeletedHunk {
8176                buffer_id,
8177                base_text_byte_range,
8178                has_trailing_newline,
8179                ..
8180            } => {
8181                let base_text_start =
8182                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8183                let base_text_end =
8184                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8185                let base_text_end = base_text_end.min(base_text_byte_range.end);
8186
8187                let mut chunks = if let Some((_, mut chunks)) = self
8188                    .diff_base_chunks
8189                    .take()
8190                    .filter(|(id, _)| id == buffer_id)
8191                {
8192                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8193                    {
8194                        chunks.seek(base_text_start..base_text_end);
8195                    }
8196                    chunks
8197                } else {
8198                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8199                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8200                };
8201
8202                let chunk = if let Some(chunk) = chunks.next() {
8203                    self.range.start += chunk.text.len();
8204                    self.diff_base_chunks = Some((*buffer_id, chunks));
8205                    chunk
8206                } else {
8207                    debug_assert!(has_trailing_newline);
8208                    self.range.start += "\n".len();
8209                    Chunk {
8210                        text: "\n",
8211                        chars: 1u128,
8212                        ..Default::default()
8213                    }
8214                };
8215                Some(chunk)
8216            }
8217        }
8218    }
8219}
8220
8221impl MultiBufferBytes<'_> {
8222    fn consume(&mut self, len: usize) {
8223        self.range.start += len;
8224        self.chunk = &self.chunk[len..];
8225
8226        if !self.range.is_empty() && self.chunk.is_empty() {
8227            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8228                self.chunk = chunk;
8229            } else if self.has_trailing_newline {
8230                self.has_trailing_newline = false;
8231                self.chunk = b"\n";
8232            } else {
8233                self.cursor.next();
8234                if let Some(region) = self.cursor.region() {
8235                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8236                        region.buffer_range.start
8237                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8238                                .min(region.buffer_range.end),
8239                    );
8240                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8241                    self.excerpt_bytes = Some(excerpt_bytes);
8242                    self.has_trailing_newline =
8243                        region.has_trailing_newline && self.range.end >= region.range.end;
8244                    if self.chunk.is_empty() && self.has_trailing_newline {
8245                        self.has_trailing_newline = false;
8246                        self.chunk = b"\n";
8247                    }
8248                }
8249            }
8250        }
8251    }
8252}
8253
8254impl<'a> Iterator for MultiBufferBytes<'a> {
8255    type Item = &'a [u8];
8256
8257    fn next(&mut self) -> Option<Self::Item> {
8258        let chunk = self.chunk;
8259        if chunk.is_empty() {
8260            None
8261        } else {
8262            self.consume(chunk.len());
8263            Some(chunk)
8264        }
8265    }
8266}
8267
8268impl io::Read for MultiBufferBytes<'_> {
8269    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8270        let len = cmp::min(buf.len(), self.chunk.len());
8271        buf[..len].copy_from_slice(&self.chunk[..len]);
8272        if len > 0 {
8273            self.consume(len);
8274        }
8275        Ok(len)
8276    }
8277}
8278
8279impl io::Read for ReversedMultiBufferBytes<'_> {
8280    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8281        let len = cmp::min(buf.len(), self.chunk.len());
8282        buf[..len].copy_from_slice(&self.chunk[..len]);
8283        buf[..len].reverse();
8284        if len > 0 {
8285            self.range.end -= len;
8286            self.chunk = &self.chunk[..self.chunk.len() - len];
8287            if !self.range.is_empty()
8288                && self.chunk.is_empty()
8289                && let Some(chunk) = self.chunks.next()
8290            {
8291                self.chunk = chunk.as_bytes();
8292            }
8293        }
8294        Ok(len)
8295    }
8296}
8297
8298impl<'a> Iterator for ExcerptChunks<'a> {
8299    type Item = Chunk<'a>;
8300
8301    fn next(&mut self) -> Option<Self::Item> {
8302        if let Some(chunk) = self.content_chunks.next() {
8303            return Some(chunk);
8304        }
8305
8306        if self.has_footer {
8307            let text = "\n";
8308            let chars = 0b1;
8309            self.has_footer = false;
8310            return Some(Chunk {
8311                text,
8312                chars,
8313                ..Default::default()
8314            });
8315        }
8316
8317        None
8318    }
8319}
8320
8321impl ToOffset for Point {
8322    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8323        snapshot.point_to_offset(*self)
8324    }
8325    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8326        snapshot.point_to_offset_utf16(*self)
8327    }
8328}
8329
8330impl ToOffset for MultiBufferOffset {
8331    #[track_caller]
8332    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8333        assert!(
8334            *self <= snapshot.len(),
8335            "offset {} is greater than the snapshot.len() {}",
8336            self.0,
8337            snapshot.len().0,
8338        );
8339        *self
8340    }
8341    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8342        snapshot.offset_to_offset_utf16(*self)
8343    }
8344}
8345
8346impl ToOffset for MultiBufferOffsetUtf16 {
8347    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8348        snapshot.offset_utf16_to_offset(*self)
8349    }
8350
8351    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8352        *self
8353    }
8354}
8355
8356impl ToOffset for PointUtf16 {
8357    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8358        snapshot.point_utf16_to_offset(*self)
8359    }
8360    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8361        snapshot.point_utf16_to_offset_utf16(*self)
8362    }
8363}
8364
8365impl ToPoint for MultiBufferOffset {
8366    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8367        snapshot.offset_to_point(*self)
8368    }
8369    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8370        snapshot.offset_to_point_utf16(*self)
8371    }
8372}
8373
8374impl ToPoint for Point {
8375    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8376        *self
8377    }
8378    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8379        snapshot.point_to_point_utf16(*self)
8380    }
8381}
8382
8383impl ToPoint for PointUtf16 {
8384    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8385        snapshot.point_utf16_to_point(*self)
8386    }
8387    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8388        *self
8389    }
8390}
8391
8392impl From<ExcerptId> for EntityId {
8393    fn from(id: ExcerptId) -> Self {
8394        EntityId::from(id.0 as u64)
8395    }
8396}
8397
8398#[cfg(debug_assertions)]
8399pub mod debug {
8400    use super::*;
8401
8402    pub trait ToMultiBufferDebugRanges {
8403        fn to_multi_buffer_debug_ranges(
8404            &self,
8405            snapshot: &MultiBufferSnapshot,
8406        ) -> Vec<Range<MultiBufferOffset>>;
8407    }
8408
8409    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8410        fn to_multi_buffer_debug_ranges(
8411            &self,
8412            snapshot: &MultiBufferSnapshot,
8413        ) -> Vec<Range<MultiBufferOffset>> {
8414            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8415        }
8416    }
8417
8418    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8419        fn to_multi_buffer_debug_ranges(
8420            &self,
8421            snapshot: &MultiBufferSnapshot,
8422        ) -> Vec<Range<MultiBufferOffset>> {
8423            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8424                .to_multi_buffer_debug_ranges(snapshot)
8425        }
8426    }
8427
8428    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8429        fn to_multi_buffer_debug_ranges(
8430            &self,
8431            snapshot: &MultiBufferSnapshot,
8432        ) -> Vec<Range<MultiBufferOffset>> {
8433            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8434        }
8435    }
8436
8437    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8438        fn to_multi_buffer_debug_ranges(
8439            &self,
8440            snapshot: &MultiBufferSnapshot,
8441        ) -> Vec<Range<MultiBufferOffset>> {
8442            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8443        }
8444    }
8445
8446    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8447        fn to_multi_buffer_debug_ranges(
8448            &self,
8449            snapshot: &MultiBufferSnapshot,
8450        ) -> Vec<Range<MultiBufferOffset>> {
8451            self.iter()
8452                .map(|item| {
8453                    let offset = item.to_offset(snapshot);
8454                    offset..offset
8455                })
8456                .collect()
8457        }
8458    }
8459
8460    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8461        fn to_multi_buffer_debug_ranges(
8462            &self,
8463            snapshot: &MultiBufferSnapshot,
8464        ) -> Vec<Range<MultiBufferOffset>> {
8465            self.iter()
8466                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8467                .collect()
8468        }
8469    }
8470}