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::{PathExcerptInsertResult, 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 merge_excerpts(
2160        &mut self,
2161        excerpt_ids: &[ExcerptId],
2162        cx: &mut Context<Self>,
2163    ) -> ExcerptId {
2164        debug_assert!(!excerpt_ids.is_empty());
2165        if excerpt_ids.len() == 1 {
2166            return excerpt_ids[0];
2167        }
2168
2169        let snapshot = self.snapshot(cx);
2170
2171        let first_range = snapshot
2172            .context_range_for_excerpt(excerpt_ids[0])
2173            .expect("first excerpt must exist");
2174        let last_range = snapshot
2175            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2176            .expect("last excerpt must exist");
2177
2178        let union_range = first_range.start..last_range.end;
2179
2180        drop(snapshot);
2181
2182        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2183        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2184
2185        excerpt_ids[0]
2186    }
2187
2188    pub fn remove_excerpts(
2189        &mut self,
2190        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2191        cx: &mut Context<Self>,
2192    ) {
2193        self.sync_mut(cx);
2194        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2195        if ids.is_empty() {
2196            return;
2197        }
2198        self.buffer_changed_since_sync.replace(true);
2199
2200        let mut snapshot = self.snapshot.get_mut();
2201        let mut new_excerpts = SumTree::default();
2202        let mut cursor = snapshot
2203            .excerpts
2204            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2205        let mut edits = Vec::new();
2206        let mut excerpt_ids = ids.iter().copied().peekable();
2207        let mut removed_buffer_ids = Vec::new();
2208
2209        while let Some(excerpt_id) = excerpt_ids.next() {
2210            self.paths_by_excerpt.remove(&excerpt_id);
2211            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2212            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2213            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2214
2215            if let Some(mut excerpt) = cursor.item() {
2216                if excerpt.id != excerpt_id {
2217                    continue;
2218                }
2219                let mut old_start = cursor.start().1;
2220
2221                // Skip over the removed excerpt.
2222                'remove_excerpts: loop {
2223                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2224                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2225                        if buffer_state.excerpts.is_empty() {
2226                            log::debug!(
2227                                "removing buffer and diff for buffer {}",
2228                                excerpt.buffer_id
2229                            );
2230                            self.buffers.remove(&excerpt.buffer_id);
2231                            removed_buffer_ids.push(excerpt.buffer_id);
2232                        }
2233                    }
2234                    cursor.next();
2235
2236                    // Skip over any subsequent excerpts that are also removed.
2237                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2238                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2239                        if let Some(next_excerpt) = cursor.item()
2240                            && next_excerpt.locator == *next_locator
2241                        {
2242                            excerpt_ids.next();
2243                            excerpt = next_excerpt;
2244                            continue 'remove_excerpts;
2245                        }
2246                    }
2247
2248                    break;
2249                }
2250
2251                // When removing the last excerpt, remove the trailing newline from
2252                // the previous excerpt.
2253                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2254                    old_start -= 1;
2255                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2256                }
2257
2258                // Push an edit for the removal of this run of excerpts.
2259                let old_end = cursor.start().1;
2260                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2261                edits.push(Edit {
2262                    old: old_start..old_end,
2263                    new: new_start..new_start,
2264                });
2265            }
2266        }
2267        let suffix = cursor.suffix();
2268        let changed_trailing_excerpt = suffix.is_empty();
2269        new_excerpts.append(suffix, ());
2270        drop(cursor);
2271        snapshot.excerpts = new_excerpts;
2272        for buffer_id in &removed_buffer_ids {
2273            self.diffs.remove(buffer_id);
2274            snapshot.diffs.remove(buffer_id);
2275        }
2276
2277        // Recalculate has_inverted_diff after removing diffs
2278        if !removed_buffer_ids.is_empty() {
2279            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2280        }
2281
2282        if changed_trailing_excerpt {
2283            snapshot.trailing_excerpt_update_count += 1;
2284        }
2285
2286        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2287        if !edits.is_empty() {
2288            self.subscriptions.publish(edits);
2289        }
2290        cx.emit(Event::Edited {
2291            edited_buffer: None,
2292        });
2293        cx.emit(Event::ExcerptsRemoved {
2294            ids,
2295            removed_buffer_ids,
2296        });
2297        cx.notify();
2298    }
2299
2300    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2301        &self,
2302        anchors: Anchors,
2303        cx: &mut Context<Self>,
2304    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2305        let mut error = None;
2306        let mut futures = Vec::new();
2307        for anchor in anchors {
2308            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2309                if let Some(buffer) = self.buffers.get(&buffer_id) {
2310                    buffer.buffer.update(cx, |buffer, _| {
2311                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2312                    });
2313                } else {
2314                    error = Some(anyhow!(
2315                        "buffer {buffer_id} is not part of this multi-buffer"
2316                    ));
2317                    break;
2318                }
2319            }
2320        }
2321        async move {
2322            if let Some(error) = error {
2323                Err(error)?;
2324            }
2325            for future in futures {
2326                future.await?;
2327            }
2328            Ok(())
2329        }
2330    }
2331
2332    pub fn text_anchor_for_position<T: ToOffset>(
2333        &self,
2334        position: T,
2335        cx: &App,
2336    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2337        let snapshot = self.read(cx);
2338        let anchor = snapshot.anchor_before(position);
2339        let buffer = self
2340            .buffers
2341            .get(&anchor.text_anchor.buffer_id?)?
2342            .buffer
2343            .clone();
2344        Some((buffer, anchor.text_anchor))
2345    }
2346
2347    fn on_buffer_event(
2348        &mut self,
2349        buffer: Entity<Buffer>,
2350        event: &language::BufferEvent,
2351        cx: &mut Context<Self>,
2352    ) {
2353        use language::BufferEvent;
2354        let buffer_id = buffer.read(cx).remote_id();
2355        cx.emit(match event {
2356            BufferEvent::Edited => Event::Edited {
2357                edited_buffer: Some(buffer),
2358            },
2359            BufferEvent::DirtyChanged => Event::DirtyChanged,
2360            BufferEvent::Saved => Event::Saved,
2361            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2362            BufferEvent::Reloaded => Event::Reloaded,
2363            BufferEvent::LanguageChanged(has_language) => {
2364                Event::LanguageChanged(buffer_id, *has_language)
2365            }
2366            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2367            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2368            BufferEvent::CapabilityChanged => {
2369                self.capability = buffer.read(cx).capability();
2370                return;
2371            }
2372            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2373        });
2374    }
2375
2376    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2377        let diff = diff.read(cx);
2378        let buffer_id = diff.buffer_id;
2379        let diff = DiffStateSnapshot {
2380            diff: diff.snapshot(cx),
2381            is_inverted: false,
2382        };
2383        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2384    }
2385
2386    fn inverted_buffer_diff_language_changed(
2387        &mut self,
2388        diff: Entity<BufferDiff>,
2389        cx: &mut Context<Self>,
2390    ) {
2391        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2392        let diff = diff.read(cx);
2393        let diff = DiffStateSnapshot {
2394            diff: diff.snapshot(cx),
2395            is_inverted: true,
2396        };
2397        self.snapshot
2398            .get_mut()
2399            .diffs
2400            .insert(base_text_buffer_id, diff);
2401    }
2402
2403    fn buffer_diff_changed(
2404        &mut self,
2405        diff: Entity<BufferDiff>,
2406        range: Range<text::Anchor>,
2407        cx: &mut Context<Self>,
2408    ) {
2409        self.sync_mut(cx);
2410
2411        let diff = diff.read(cx);
2412        let buffer_id = diff.buffer_id;
2413
2414        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2415            return;
2416        };
2417        let new_diff = DiffStateSnapshot {
2418            diff: diff.snapshot(cx),
2419            is_inverted: false,
2420        };
2421        let mut snapshot = self.snapshot.get_mut();
2422        let base_text_changed = snapshot
2423            .diffs
2424            .get(&buffer_id)
2425            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2426        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2427
2428        let buffer = buffer_state.buffer.read(cx);
2429        let diff_change_range = range.to_offset(buffer);
2430
2431        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2432        let edits = Self::sync_diff_transforms(
2433            &mut snapshot,
2434            excerpt_edits,
2435            DiffChangeKind::DiffUpdated {
2436                base_changed: base_text_changed,
2437            },
2438        );
2439        if !edits.is_empty() {
2440            self.subscriptions.publish(edits);
2441        }
2442        cx.emit(Event::Edited {
2443            edited_buffer: None,
2444        });
2445    }
2446
2447    fn inverted_buffer_diff_changed(
2448        &mut self,
2449        diff: Entity<BufferDiff>,
2450        diff_change_range: Range<usize>,
2451        cx: &mut Context<Self>,
2452    ) {
2453        self.sync_mut(cx);
2454
2455        let diff = diff.read(cx);
2456        let base_text_buffer_id = diff.base_text(cx).remote_id();
2457        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2458            return;
2459        };
2460
2461        let new_diff = DiffStateSnapshot {
2462            diff: diff.snapshot(cx),
2463            is_inverted: true,
2464        };
2465        let mut snapshot = self.snapshot.get_mut();
2466        snapshot
2467            .diffs
2468            .insert_or_replace(base_text_buffer_id, new_diff);
2469
2470        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2471        let edits = Self::sync_diff_transforms(
2472            &mut snapshot,
2473            excerpt_edits,
2474            DiffChangeKind::DiffUpdated {
2475                // We don't read this field for inverted diffs.
2476                base_changed: false,
2477            },
2478        );
2479        if !edits.is_empty() {
2480            self.subscriptions.publish(edits);
2481        }
2482        cx.emit(Event::Edited {
2483            edited_buffer: None,
2484        });
2485    }
2486
2487    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2488        self.buffers.values().map(|state| state.buffer.clone())
2489    }
2490
2491    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2492        self.all_buffers_iter().collect()
2493    }
2494
2495    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2496        self.buffers.keys().copied()
2497    }
2498
2499    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2500        self.all_buffer_ids_iter().collect()
2501    }
2502
2503    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2504        self.buffers
2505            .get(&buffer_id)
2506            .map(|state| state.buffer.clone())
2507    }
2508
2509    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2510        self.point_to_buffer_offset(point, cx)
2511            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2512    }
2513
2514    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2515        let buffer_id = self
2516            .snapshot
2517            .borrow()
2518            .excerpts
2519            .first()
2520            .map(|excerpt| excerpt.buffer.remote_id());
2521        buffer_id
2522            .and_then(|buffer_id| self.buffer(buffer_id))
2523            .map(|buffer| {
2524                let buffer = buffer.read(cx);
2525                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2526            })
2527            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2528    }
2529
2530    pub fn language_settings_at<'a, T: ToOffset>(
2531        &'a self,
2532        point: T,
2533        cx: &'a App,
2534    ) -> Cow<'a, LanguageSettings> {
2535        let mut language = None;
2536        let mut file = None;
2537        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2538            let buffer = buffer.read(cx);
2539            language = buffer.language_at(offset);
2540            file = buffer.file();
2541        }
2542        language_settings(language.map(|l| l.name()), file, cx)
2543    }
2544
2545    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2546        self.buffers.values().for_each(|state| f(&state.buffer))
2547    }
2548
2549    pub fn explicit_title(&self) -> Option<&str> {
2550        self.title.as_deref()
2551    }
2552
2553    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2554        if let Some(title) = self.title.as_ref() {
2555            return title.into();
2556        }
2557
2558        if let Some(buffer) = self.as_singleton() {
2559            let buffer = buffer.read(cx);
2560
2561            if let Some(file) = buffer.file() {
2562                return file.file_name(cx).into();
2563            }
2564
2565            if let Some(title) = self.buffer_content_title(buffer) {
2566                return title;
2567            }
2568        };
2569
2570        "untitled".into()
2571    }
2572
2573    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2574        let mut is_leading_whitespace = true;
2575        let mut count = 0;
2576        let mut prev_was_space = false;
2577        let mut title = String::new();
2578
2579        for ch in buffer.snapshot().chars() {
2580            if is_leading_whitespace && ch.is_whitespace() {
2581                continue;
2582            }
2583
2584            is_leading_whitespace = false;
2585
2586            if ch == '\n' || count >= 40 {
2587                break;
2588            }
2589
2590            if ch.is_whitespace() {
2591                if !prev_was_space {
2592                    title.push(' ');
2593                    count += 1;
2594                    prev_was_space = true;
2595                }
2596            } else {
2597                title.push(ch);
2598                count += 1;
2599                prev_was_space = false;
2600            }
2601        }
2602
2603        let title = title.trim_end().to_string();
2604
2605        if title.is_empty() {
2606            return None;
2607        }
2608
2609        Some(title.into())
2610    }
2611
2612    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2613        self.title = Some(title);
2614        cx.notify();
2615    }
2616
2617    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2618    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2619        for buffer_state in self.buffers.values() {
2620            buffer_state
2621                .buffer
2622                .update(cx, |buffer, _cx| buffer.refresh_preview());
2623        }
2624    }
2625
2626    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2627    pub fn preserve_preview(&self, cx: &App) -> bool {
2628        self.buffers
2629            .values()
2630            .all(|state| state.buffer.read(cx).preserve_preview())
2631    }
2632
2633    #[cfg(any(test, feature = "test-support"))]
2634    pub fn is_parsing(&self, cx: &App) -> bool {
2635        self.as_singleton().unwrap().read(cx).is_parsing()
2636    }
2637
2638    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2639        let buffer_id = diff.read(cx).buffer_id;
2640
2641        if let Some(existing_diff) = self.diff_for(buffer_id)
2642            && diff.entity_id() == existing_diff.entity_id()
2643        {
2644            return;
2645        }
2646
2647        self.buffer_diff_changed(
2648            diff.clone(),
2649            text::Anchor::min_max_range_for_buffer(buffer_id),
2650            cx,
2651        );
2652        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2653    }
2654
2655    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2656        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2657        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2658        self.snapshot.get_mut().has_inverted_diff = true;
2659        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2660        self.diffs
2661            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2662    }
2663
2664    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2665        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2666    }
2667
2668    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2669        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2670    }
2671
2672    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2673        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2674    }
2675
2676    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2677        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2678        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2679    }
2680
2681    pub fn all_diff_hunks_expanded(&self) -> bool {
2682        self.snapshot.borrow().all_diff_hunks_expanded
2683    }
2684
2685    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2686        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2687        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2688    }
2689
2690    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2691        self.snapshot.get_mut().show_deleted_hunks = show;
2692        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2693    }
2694
2695    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2696        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2697    }
2698
2699    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2700        self.read(cx)
2701            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2702            .nth(1)
2703            .is_some()
2704    }
2705
2706    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2707        let snapshot = self.read(cx);
2708        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2709        let offset_range = range.to_offset(&snapshot);
2710        cursor.seek(&offset_range.start, Bias::Left);
2711        while let Some(item) = cursor.item() {
2712            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2713                break;
2714            }
2715            if item.hunk_info().is_some() {
2716                return true;
2717            }
2718            cursor.next();
2719        }
2720        false
2721    }
2722
2723    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2724        let snapshot = self.read(cx);
2725        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2726        for range in ranges {
2727            let range = range.to_point(&snapshot);
2728            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2729            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2730                .min(snapshot.len());
2731            cursor.seek(&start, Bias::Right);
2732            while let Some(item) = cursor.item() {
2733                if *cursor.start() >= end {
2734                    break;
2735                }
2736                if item.hunk_info().is_some() {
2737                    return true;
2738                }
2739                cursor.next();
2740            }
2741        }
2742        false
2743    }
2744
2745    pub fn expand_or_collapse_diff_hunks_inner(
2746        &mut self,
2747        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2748        expand: bool,
2749        cx: &mut Context<Self>,
2750    ) {
2751        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2752            return;
2753        }
2754        self.sync_mut(cx);
2755        let mut snapshot = self.snapshot.get_mut();
2756        let mut excerpt_edits = Vec::new();
2757        let mut last_hunk_row = None;
2758        for (range, end_excerpt_id) in ranges {
2759            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2760                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2761                    continue;
2762                }
2763                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2764                    continue;
2765                }
2766                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2767                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2768                let start = snapshot.excerpt_offset_for_anchor(&start);
2769                let end = snapshot.excerpt_offset_for_anchor(&end);
2770                last_hunk_row = Some(diff_hunk.row_range.start);
2771                excerpt_edits.push(text::Edit {
2772                    old: start..end,
2773                    new: start..end,
2774                });
2775            }
2776        }
2777
2778        let edits = Self::sync_diff_transforms(
2779            &mut snapshot,
2780            excerpt_edits,
2781            DiffChangeKind::ExpandOrCollapseHunks { expand },
2782        );
2783        if !edits.is_empty() {
2784            self.subscriptions.publish(edits);
2785        }
2786        cx.emit(Event::DiffHunksToggled);
2787        cx.emit(Event::Edited {
2788            edited_buffer: None,
2789        });
2790    }
2791
2792    pub fn expand_or_collapse_diff_hunks(
2793        &mut self,
2794        ranges: Vec<Range<Anchor>>,
2795        expand: bool,
2796        cx: &mut Context<Self>,
2797    ) {
2798        let snapshot = self.snapshot.borrow().clone();
2799        let ranges = ranges.iter().map(move |range| {
2800            let end_excerpt_id = range.end.excerpt_id;
2801            let range = range.to_point(&snapshot);
2802            let mut peek_end = range.end;
2803            if range.end.row < snapshot.max_row().0 {
2804                peek_end = Point::new(range.end.row + 1, 0);
2805            };
2806            (range.start..peek_end, end_excerpt_id)
2807        });
2808        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2809    }
2810
2811    pub fn resize_excerpt(
2812        &mut self,
2813        id: ExcerptId,
2814        range: Range<text::Anchor>,
2815        cx: &mut Context<Self>,
2816    ) {
2817        self.sync_mut(cx);
2818
2819        let mut snapshot = self.snapshot.get_mut();
2820        let locator = snapshot.excerpt_locator_for_id(id);
2821        let mut new_excerpts = SumTree::default();
2822        let mut cursor = snapshot
2823            .excerpts
2824            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2825        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2826
2827        let prefix = cursor.slice(&Some(locator), Bias::Left);
2828        new_excerpts.append(prefix, ());
2829
2830        let mut excerpt = cursor.item().unwrap().clone();
2831        let old_text_len = excerpt.text_summary.len;
2832
2833        excerpt.range.context.start = range.start;
2834        excerpt.range.context.end = range.end;
2835        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2836
2837        excerpt.text_summary = excerpt
2838            .buffer
2839            .text_summary_for_range(excerpt.range.context.clone());
2840
2841        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2842        let old_start_offset = cursor.start().1;
2843        let new_text_len = excerpt.text_summary.len;
2844        let edit = Edit {
2845            old: old_start_offset..old_start_offset + old_text_len,
2846            new: new_start_offset..new_start_offset + new_text_len,
2847        };
2848
2849        if let Some(last_edit) = edits.last_mut() {
2850            if last_edit.old.end == edit.old.start {
2851                last_edit.old.end = edit.old.end;
2852                last_edit.new.end = edit.new.end;
2853            } else {
2854                edits.push(edit);
2855            }
2856        } else {
2857            edits.push(edit);
2858        }
2859
2860        new_excerpts.push(excerpt, ());
2861
2862        cursor.next();
2863
2864        new_excerpts.append(cursor.suffix(), ());
2865
2866        drop(cursor);
2867        snapshot.excerpts = new_excerpts;
2868
2869        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2870        if !edits.is_empty() {
2871            self.subscriptions.publish(edits);
2872        }
2873        cx.emit(Event::Edited {
2874            edited_buffer: None,
2875        });
2876        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2877        cx.notify();
2878    }
2879
2880    pub fn expand_excerpts(
2881        &mut self,
2882        ids: impl IntoIterator<Item = ExcerptId>,
2883        line_count: u32,
2884        direction: ExpandExcerptDirection,
2885        cx: &mut Context<Self>,
2886    ) {
2887        if line_count == 0 {
2888            return;
2889        }
2890        self.sync_mut(cx);
2891        if !self.excerpts_by_path.is_empty() {
2892            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2893            return;
2894        }
2895        let mut snapshot = self.snapshot.get_mut();
2896
2897        let ids = ids.into_iter().collect::<Vec<_>>();
2898        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2899        let mut new_excerpts = SumTree::default();
2900        let mut cursor = snapshot
2901            .excerpts
2902            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2903        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2904
2905        for locator in &locators {
2906            let prefix = cursor.slice(&Some(locator), Bias::Left);
2907            new_excerpts.append(prefix, ());
2908
2909            let mut excerpt = cursor.item().unwrap().clone();
2910            let old_text_len = excerpt.text_summary.len;
2911
2912            let up_line_count = if direction.should_expand_up() {
2913                line_count
2914            } else {
2915                0
2916            };
2917
2918            let start_row = excerpt
2919                .range
2920                .context
2921                .start
2922                .to_point(&excerpt.buffer)
2923                .row
2924                .saturating_sub(up_line_count);
2925            let start_point = Point::new(start_row, 0);
2926            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2927
2928            let down_line_count = if direction.should_expand_down() {
2929                line_count
2930            } else {
2931                0
2932            };
2933
2934            let mut end_point = excerpt.buffer.clip_point(
2935                excerpt.range.context.end.to_point(&excerpt.buffer)
2936                    + Point::new(down_line_count, 0),
2937                Bias::Left,
2938            );
2939            end_point.column = excerpt.buffer.line_len(end_point.row);
2940            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2941            excerpt.max_buffer_row = end_point.row;
2942
2943            excerpt.text_summary = excerpt
2944                .buffer
2945                .text_summary_for_range(excerpt.range.context.clone());
2946
2947            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2948            let old_start_offset = cursor.start().1;
2949            let new_text_len = excerpt.text_summary.len;
2950            let edit = Edit {
2951                old: old_start_offset..old_start_offset + old_text_len,
2952                new: new_start_offset..new_start_offset + new_text_len,
2953            };
2954
2955            if let Some(last_edit) = edits.last_mut() {
2956                if last_edit.old.end == edit.old.start {
2957                    last_edit.old.end = edit.old.end;
2958                    last_edit.new.end = edit.new.end;
2959                } else {
2960                    edits.push(edit);
2961                }
2962            } else {
2963                edits.push(edit);
2964            }
2965
2966            new_excerpts.push(excerpt, ());
2967
2968            cursor.next();
2969        }
2970
2971        new_excerpts.append(cursor.suffix(), ());
2972
2973        drop(cursor);
2974        snapshot.excerpts = new_excerpts;
2975
2976        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2977        if !edits.is_empty() {
2978            self.subscriptions.publish(edits);
2979        }
2980        cx.emit(Event::Edited {
2981            edited_buffer: None,
2982        });
2983        cx.emit(Event::ExcerptsExpanded { ids });
2984        cx.notify();
2985    }
2986
2987    #[ztracing::instrument(skip_all)]
2988    fn sync(&self, cx: &App) {
2989        let changed = self.buffer_changed_since_sync.replace(false);
2990        if !changed {
2991            return;
2992        }
2993        let edits = Self::sync_from_buffer_changes(
2994            &mut self.snapshot.borrow_mut(),
2995            &self.buffers,
2996            &self.diffs,
2997            cx,
2998        );
2999        if !edits.is_empty() {
3000            self.subscriptions.publish(edits);
3001        }
3002    }
3003
3004    fn sync_mut(&mut self, cx: &App) {
3005        let changed = self.buffer_changed_since_sync.replace(false);
3006        if !changed {
3007            return;
3008        }
3009        let edits =
3010            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3011
3012        if !edits.is_empty() {
3013            self.subscriptions.publish(edits);
3014        }
3015    }
3016
3017    fn sync_from_buffer_changes(
3018        snapshot: &mut MultiBufferSnapshot,
3019        buffers: &BTreeMap<BufferId, BufferState>,
3020        diffs: &HashMap<BufferId, DiffState>,
3021        cx: &App,
3022    ) -> Vec<Edit<MultiBufferOffset>> {
3023        let MultiBufferSnapshot {
3024            excerpts,
3025            diffs: buffer_diff,
3026            diff_transforms: _,
3027            non_text_state_update_count,
3028            edit_count,
3029            is_dirty,
3030            has_deleted_file,
3031            has_conflict,
3032            has_inverted_diff: _,
3033            singleton: _,
3034            excerpt_ids: _,
3035            replaced_excerpts: _,
3036            trailing_excerpt_update_count: _,
3037            all_diff_hunks_expanded: _,
3038            show_deleted_hunks: _,
3039            use_extended_diff_range: _,
3040            show_headers: _,
3041        } = snapshot;
3042        *is_dirty = false;
3043        *has_deleted_file = false;
3044        *has_conflict = false;
3045
3046        if !diffs.is_empty() {
3047            let mut diffs_to_add = Vec::new();
3048            for (id, diff) in diffs {
3049                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3050                // and use the diff hunk base text ranges to compute diff transforms.
3051                // Those base text ranges are usize, so make sure if the base text changed
3052                // we also update the diff snapshot so that we don't use stale offsets
3053                if buffer_diff.get(id).is_none_or(|existing_diff| {
3054                    if !existing_diff.is_inverted {
3055                        return false;
3056                    }
3057                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3058                    base_text.remote_id() != existing_diff.base_text().remote_id()
3059                        || base_text
3060                            .version()
3061                            .changed_since(existing_diff.base_text().version())
3062                }) {
3063                    if diffs_to_add.capacity() == 0 {
3064                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3065                        // meaning re-allocations will be fairly expensive
3066                        diffs_to_add.reserve(diffs.len());
3067                    }
3068                    diffs_to_add.push((*id, diff.snapshot(cx)));
3069                }
3070            }
3071            buffer_diff.extend(diffs_to_add);
3072        }
3073
3074        let mut excerpts_to_edit = Vec::new();
3075        let mut non_text_state_updated = false;
3076        let mut edited = false;
3077        for buffer_state in buffers.values() {
3078            let buffer = buffer_state.buffer.read(cx);
3079            let version = buffer.version();
3080            let non_text_state_update_count = buffer.non_text_state_update_count();
3081
3082            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3083            let buffer_non_text_state_updated =
3084                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3085            if buffer_edited || buffer_non_text_state_updated {
3086                *buffer_state.last_version.borrow_mut() = version;
3087                buffer_state
3088                    .last_non_text_state_update_count
3089                    .set(non_text_state_update_count);
3090                excerpts_to_edit.extend(
3091                    buffer_state
3092                        .excerpts
3093                        .iter()
3094                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3095                );
3096            }
3097
3098            edited |= buffer_edited;
3099            non_text_state_updated |= buffer_non_text_state_updated;
3100            *is_dirty |= buffer.is_dirty();
3101            *has_deleted_file |= buffer
3102                .file()
3103                .is_some_and(|file| file.disk_state().is_deleted());
3104            *has_conflict |= buffer.has_conflict();
3105        }
3106        if edited {
3107            *edit_count += 1;
3108        }
3109        if non_text_state_updated {
3110            *non_text_state_update_count += 1;
3111        }
3112
3113        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3114
3115        let mut edits = Vec::new();
3116        let mut new_excerpts = SumTree::default();
3117        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3118
3119        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3120            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3121            let old_excerpt = cursor.item().unwrap();
3122            let buffer = buffer.read(cx);
3123            let buffer_id = buffer.remote_id();
3124            let mut new_excerpt;
3125            if buffer_edited {
3126                edits.extend(
3127                    buffer
3128                        .edits_since_in_range::<usize>(
3129                            old_excerpt.buffer.version(),
3130                            old_excerpt.range.context.clone(),
3131                        )
3132                        .map(|edit| {
3133                            let excerpt_old_start = cursor.start().1;
3134                            let excerpt_new_start =
3135                                ExcerptDimension(new_excerpts.summary().text.len);
3136                            let old_start = excerpt_old_start + edit.old.start;
3137                            let old_end = excerpt_old_start + edit.old.end;
3138                            let new_start = excerpt_new_start + edit.new.start;
3139                            let new_end = excerpt_new_start + edit.new.end;
3140                            Edit {
3141                                old: old_start..old_end,
3142                                new: new_start..new_end,
3143                            }
3144                        }),
3145                );
3146
3147                new_excerpt = Excerpt::new(
3148                    old_excerpt.id,
3149                    locator.clone(),
3150                    buffer_id,
3151                    Arc::new(buffer.snapshot()),
3152                    old_excerpt.range.clone(),
3153                    old_excerpt.has_trailing_newline,
3154                );
3155            } else {
3156                new_excerpt = old_excerpt.clone();
3157                new_excerpt.buffer = Arc::new(buffer.snapshot());
3158            }
3159
3160            new_excerpts.push(new_excerpt, ());
3161            cursor.next();
3162        }
3163        new_excerpts.append(cursor.suffix(), ());
3164
3165        drop(cursor);
3166        *excerpts = new_excerpts;
3167
3168        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3169    }
3170
3171    fn sync_diff_transforms(
3172        snapshot: &mut MultiBufferSnapshot,
3173        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3174        change_kind: DiffChangeKind,
3175    ) -> Vec<Edit<MultiBufferOffset>> {
3176        if excerpt_edits.is_empty() {
3177            return vec![];
3178        }
3179
3180        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3181        let mut old_diff_transforms = snapshot
3182            .diff_transforms
3183            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3184        let mut new_diff_transforms = SumTree::default();
3185        let mut old_expanded_hunks = HashSet::default();
3186        let mut output_edits = Vec::new();
3187        let mut output_delta = 0_isize;
3188        let mut at_transform_boundary = true;
3189        let mut end_of_current_insert = None;
3190
3191        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3192        while let Some(edit) = excerpt_edits.next() {
3193            excerpts.seek_forward(&edit.new.start, Bias::Right);
3194            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3195                excerpts.prev();
3196            }
3197
3198            // Keep any transforms that are before the edit.
3199            if at_transform_boundary {
3200                at_transform_boundary = false;
3201                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3202                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3203                if let Some(transform) = old_diff_transforms.item()
3204                    && old_diff_transforms.end().0 == edit.old.start
3205                    && old_diff_transforms.start().0 < edit.old.start
3206                {
3207                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3208                    old_diff_transforms.next();
3209                }
3210            }
3211
3212            // Compute the start of the edit in output coordinates.
3213            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3214            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3215            let edit_new_start =
3216                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3217
3218            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3219                &edit,
3220                &mut excerpts,
3221                &mut old_diff_transforms,
3222                &mut new_diff_transforms,
3223                &mut end_of_current_insert,
3224                &mut old_expanded_hunks,
3225                snapshot,
3226                change_kind,
3227            );
3228
3229            // Compute the end of the edit in output coordinates.
3230            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3231            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3232            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3233            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3234            let output_edit = Edit {
3235                old: edit_old_start..edit_old_end,
3236                new: edit_new_start..edit_new_end,
3237            };
3238
3239            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3240            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3241            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3242                output_edits.push(output_edit);
3243            }
3244
3245            // If this is the last edit that intersects the current diff transform,
3246            // then recreate the content up to the end of this transform, to prepare
3247            // for reusing additional slices of the old transforms.
3248            if excerpt_edits
3249                .peek()
3250                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3251            {
3252                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3253                    && match old_diff_transforms.item() {
3254                        Some(DiffTransform::BufferContent {
3255                            inserted_hunk_info: Some(hunk),
3256                            ..
3257                        }) => excerpts.item().is_some_and(|excerpt| {
3258                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3259                                && diff.is_inverted
3260                            {
3261                                return true;
3262                            }
3263                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3264                        }),
3265                        _ => true,
3266                    };
3267
3268                let mut excerpt_offset = edit.new.end;
3269                if !keep_next_old_transform {
3270                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3271                    old_diff_transforms.next();
3272                }
3273
3274                old_expanded_hunks.clear();
3275                Self::push_buffer_content_transform(
3276                    snapshot,
3277                    &mut new_diff_transforms,
3278                    excerpt_offset,
3279                    end_of_current_insert,
3280                );
3281                at_transform_boundary = true;
3282            }
3283        }
3284
3285        // Keep any transforms that are after the last edit.
3286        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3287
3288        // Ensure there's always at least one buffer content transform.
3289        if new_diff_transforms.is_empty() {
3290            new_diff_transforms.push(
3291                DiffTransform::BufferContent {
3292                    summary: Default::default(),
3293                    inserted_hunk_info: None,
3294                },
3295                (),
3296            );
3297        }
3298
3299        drop(old_diff_transforms);
3300        drop(excerpts);
3301        snapshot.diff_transforms = new_diff_transforms;
3302        snapshot.edit_count += 1;
3303
3304        #[cfg(any(test, feature = "test-support"))]
3305        snapshot.check_invariants();
3306        output_edits
3307    }
3308
3309    fn recompute_diff_transforms_for_edit(
3310        edit: &Edit<ExcerptOffset>,
3311        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3312        old_diff_transforms: &mut Cursor<
3313            DiffTransform,
3314            Dimensions<ExcerptOffset, MultiBufferOffset>,
3315        >,
3316        new_diff_transforms: &mut SumTree<DiffTransform>,
3317        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3318        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3319        snapshot: &MultiBufferSnapshot,
3320        change_kind: DiffChangeKind,
3321    ) -> bool {
3322        log::trace!(
3323            "recomputing diff transform for edit {:?} => {:?}",
3324            edit.old.start..edit.old.end,
3325            edit.new.start..edit.new.end
3326        );
3327
3328        // Record which hunks were previously expanded.
3329        while let Some(item) = old_diff_transforms.item() {
3330            if let Some(hunk_info) = item.hunk_info() {
3331                log::trace!(
3332                    "previously expanded hunk at {:?}",
3333                    old_diff_transforms.start()
3334                );
3335                old_expanded_hunks.insert(hunk_info);
3336            }
3337            if old_diff_transforms.end().0 > edit.old.end {
3338                break;
3339            }
3340            old_diff_transforms.next();
3341        }
3342
3343        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3344        // For inverted diffs, hunks are always shown, so we can't skip this.
3345        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3346        if old_expanded_hunks.is_empty()
3347            && change_kind == DiffChangeKind::BufferEdited
3348            && !all_diff_hunks_expanded
3349            && !snapshot.has_inverted_diff
3350        {
3351            return false;
3352        }
3353
3354        // Visit each excerpt that intersects the edit.
3355        let mut did_expand_hunks = false;
3356        while let Some(excerpt) = excerpts.item() {
3357            // Recompute the expanded hunks in the portion of the excerpt that
3358            // intersects the edit.
3359            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3360                let buffer = &excerpt.buffer;
3361                let excerpt_start = *excerpts.start();
3362                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3363                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3364                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3365                let edit_buffer_start =
3366                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3367                let edit_buffer_end =
3368                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3369                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3370
3371                if diff.is_inverted {
3372                    for hunk in diff.hunks_intersecting_base_text_range(
3373                        edit_buffer_start..edit_buffer_end,
3374                        diff.original_buffer_snapshot(),
3375                    ) {
3376                        did_expand_hunks = true;
3377                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3378                        if hunk_buffer_range.start < excerpt_buffer_start {
3379                            log::trace!("skipping hunk that starts before excerpt");
3380                            continue;
3381                        }
3382                        hunk_buffer_range.end.to_point(&excerpt.buffer);
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                        Self::push_buffer_content_transform(
3388                            snapshot,
3389                            new_diff_transforms,
3390                            hunk_excerpt_start,
3391                            *end_of_current_insert,
3392                        );
3393                        if !hunk_buffer_range.is_empty() {
3394                            let hunk_info = DiffTransformHunkInfo {
3395                                excerpt_id: excerpt.id,
3396                                hunk_start_anchor: hunk.buffer_range.start,
3397                                hunk_secondary_status: hunk.secondary_status,
3398                                is_logically_deleted: true,
3399                            };
3400                            *end_of_current_insert =
3401                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3402                        }
3403                    }
3404                } else {
3405                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3406                        ..buffer.anchor_after(edit_buffer_end);
3407                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3408                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3409                            continue;
3410                        }
3411
3412                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3413                        if hunk_buffer_range.start < excerpt_buffer_start {
3414                            log::trace!("skipping hunk that starts before excerpt");
3415                            continue;
3416                        }
3417
3418                        let hunk_info = DiffTransformHunkInfo {
3419                            excerpt_id: excerpt.id,
3420                            hunk_start_anchor: hunk.buffer_range.start,
3421                            hunk_secondary_status: hunk.secondary_status,
3422                            is_logically_deleted: false,
3423                        };
3424
3425                        let hunk_excerpt_start = excerpt_start
3426                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3427                        let hunk_excerpt_end = excerpt_end
3428                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3429
3430                        Self::push_buffer_content_transform(
3431                            snapshot,
3432                            new_diff_transforms,
3433                            hunk_excerpt_start,
3434                            *end_of_current_insert,
3435                        );
3436
3437                        // For every existing hunk, determine if it was previously expanded
3438                        // and if it should currently be expanded.
3439                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3440                        let should_expand_hunk = match &change_kind {
3441                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3442                                was_previously_expanded || all_diff_hunks_expanded
3443                            }
3444                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3445                                let intersects = hunk_buffer_range.is_empty()
3446                                    || hunk_buffer_range.end > edit_buffer_start;
3447                                if *expand {
3448                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3449                                } else {
3450                                    !intersects
3451                                        && (was_previously_expanded || all_diff_hunks_expanded)
3452                                }
3453                            }
3454                            _ => was_previously_expanded || all_diff_hunks_expanded,
3455                        };
3456
3457                        if should_expand_hunk {
3458                            did_expand_hunks = true;
3459                            log::trace!(
3460                                "expanding hunk {:?}, excerpt:{:?}",
3461                                hunk_excerpt_start..hunk_excerpt_end,
3462                                excerpt.id
3463                            );
3464
3465                            if !hunk.diff_base_byte_range.is_empty()
3466                                && hunk_buffer_range.start >= edit_buffer_start
3467                                && hunk_buffer_range.start <= excerpt_buffer_end
3468                                && snapshot.show_deleted_hunks
3469                            {
3470                                let base_text = diff.base_text();
3471                                let mut text_cursor =
3472                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3473                                let mut base_text_summary = text_cursor
3474                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3475
3476                                let mut has_trailing_newline = false;
3477                                if base_text_summary.last_line_chars > 0 {
3478                                    base_text_summary += TextSummary::newline();
3479                                    has_trailing_newline = true;
3480                                }
3481
3482                                new_diff_transforms.push(
3483                                    DiffTransform::DeletedHunk {
3484                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3485                                        summary: base_text_summary,
3486                                        buffer_id: excerpt.buffer_id,
3487                                        hunk_info,
3488                                        has_trailing_newline,
3489                                    },
3490                                    (),
3491                                );
3492                            }
3493
3494                            if !hunk_buffer_range.is_empty() {
3495                                *end_of_current_insert =
3496                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3497                            }
3498                        }
3499                    }
3500                }
3501            }
3502
3503            if excerpts.end() <= edit.new.end {
3504                excerpts.next();
3505            } else {
3506                break;
3507            }
3508        }
3509
3510        did_expand_hunks || !old_expanded_hunks.is_empty()
3511    }
3512
3513    fn append_diff_transforms(
3514        new_transforms: &mut SumTree<DiffTransform>,
3515        subtree: SumTree<DiffTransform>,
3516    ) {
3517        if let Some(DiffTransform::BufferContent {
3518            inserted_hunk_info,
3519            summary,
3520        }) = subtree.first()
3521            && Self::extend_last_buffer_content_transform(
3522                new_transforms,
3523                *inserted_hunk_info,
3524                *summary,
3525            )
3526        {
3527            let mut cursor = subtree.cursor::<()>(());
3528            cursor.next();
3529            cursor.next();
3530            new_transforms.append(cursor.suffix(), ());
3531            return;
3532        }
3533        new_transforms.append(subtree, ());
3534    }
3535
3536    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3537        if let DiffTransform::BufferContent {
3538            inserted_hunk_info: inserted_hunk_anchor,
3539            summary,
3540        } = transform
3541            && Self::extend_last_buffer_content_transform(
3542                new_transforms,
3543                inserted_hunk_anchor,
3544                summary,
3545            )
3546        {
3547            return;
3548        }
3549        new_transforms.push(transform, ());
3550    }
3551
3552    fn push_buffer_content_transform(
3553        old_snapshot: &MultiBufferSnapshot,
3554        new_transforms: &mut SumTree<DiffTransform>,
3555        end_offset: ExcerptOffset,
3556        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3557    ) {
3558        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3559            (end_offset.min(insertion_end_offset), Some(hunk_info))
3560        });
3561        let unchanged_region = [(end_offset, None)];
3562
3563        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3564        {
3565            let start_offset = new_transforms.summary().excerpt_len();
3566            if end_offset <= start_offset {
3567                continue;
3568            }
3569            let summary_to_add = old_snapshot
3570                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3571
3572            if !Self::extend_last_buffer_content_transform(
3573                new_transforms,
3574                inserted_hunk_info,
3575                summary_to_add,
3576            ) {
3577                new_transforms.push(
3578                    DiffTransform::BufferContent {
3579                        summary: summary_to_add,
3580                        inserted_hunk_info,
3581                    },
3582                    (),
3583                )
3584            }
3585        }
3586    }
3587
3588    fn extend_last_buffer_content_transform(
3589        new_transforms: &mut SumTree<DiffTransform>,
3590        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3591        summary_to_add: MBTextSummary,
3592    ) -> bool {
3593        let mut did_extend = false;
3594        new_transforms.update_last(
3595            |last_transform| {
3596                if let DiffTransform::BufferContent {
3597                    summary,
3598                    inserted_hunk_info: inserted_hunk_anchor,
3599                } = last_transform
3600                    && *inserted_hunk_anchor == new_inserted_hunk_info
3601                {
3602                    *summary += summary_to_add;
3603                    did_extend = true;
3604                }
3605            },
3606            (),
3607        );
3608        did_extend
3609    }
3610}
3611
3612fn build_excerpt_ranges(
3613    ranges: impl IntoIterator<Item = Range<Point>>,
3614    context_line_count: u32,
3615    buffer_snapshot: &BufferSnapshot,
3616) -> Vec<ExcerptRange<Point>> {
3617    ranges
3618        .into_iter()
3619        .map(|range| {
3620            let start_row = range.start.row.saturating_sub(context_line_count);
3621            let start = Point::new(start_row, 0);
3622            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3623            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3624            ExcerptRange {
3625                context: start..end,
3626                primary: range,
3627            }
3628        })
3629        .collect()
3630}
3631
3632#[cfg(any(test, feature = "test-support"))]
3633impl MultiBuffer {
3634    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3635        let buffer = cx.new(|cx| Buffer::local(text, cx));
3636        cx.new(|cx| Self::singleton(buffer, cx))
3637    }
3638
3639    pub fn build_multi<const COUNT: usize>(
3640        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3641        cx: &mut gpui::App,
3642    ) -> Entity<Self> {
3643        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3644        for (text, ranges) in excerpts {
3645            let buffer = cx.new(|cx| Buffer::local(text, cx));
3646            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3647            multi.update(cx, |multi, cx| {
3648                multi.push_excerpts(buffer, excerpt_ranges, cx)
3649            });
3650        }
3651
3652        multi
3653    }
3654
3655    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3656        cx.new(|cx| Self::singleton(buffer, cx))
3657    }
3658
3659    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3660        cx.new(|cx| {
3661            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3662            let mutation_count = rng.random_range(1..=5);
3663            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3664            multibuffer
3665        })
3666    }
3667
3668    pub fn randomly_edit(
3669        &mut self,
3670        rng: &mut impl rand::Rng,
3671        edit_count: usize,
3672        cx: &mut Context<Self>,
3673    ) {
3674        use util::RandomCharIter;
3675
3676        let snapshot = self.read(cx);
3677        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3678        let mut last_end = None;
3679        for _ in 0..edit_count {
3680            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3681                break;
3682            }
3683
3684            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3685            let end =
3686                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3687            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3688            last_end = Some(end);
3689
3690            let mut range = start..end;
3691            if rng.random_bool(0.2) {
3692                mem::swap(&mut range.start, &mut range.end);
3693            }
3694
3695            let new_text_len = rng.random_range(0..10);
3696            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3697
3698            edits.push((range, new_text.into()));
3699        }
3700        log::info!("mutating multi-buffer with {:?}", edits);
3701        drop(snapshot);
3702
3703        self.edit(edits, None, cx);
3704    }
3705
3706    pub fn randomly_edit_excerpts(
3707        &mut self,
3708        rng: &mut impl rand::Rng,
3709        mutation_count: usize,
3710        cx: &mut Context<Self>,
3711    ) {
3712        use rand::prelude::*;
3713        use std::env;
3714        use util::RandomCharIter;
3715
3716        let max_excerpts = env::var("MAX_EXCERPTS")
3717            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3718            .unwrap_or(5);
3719
3720        let mut buffers = Vec::new();
3721        for _ in 0..mutation_count {
3722            if rng.random_bool(0.05) {
3723                log::info!("Clearing multi-buffer");
3724                self.clear(cx);
3725                continue;
3726            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3727                let ids = self.excerpt_ids();
3728                let mut excerpts = HashSet::default();
3729                for _ in 0..rng.random_range(0..ids.len()) {
3730                    excerpts.extend(ids.choose(rng).copied());
3731                }
3732
3733                let line_count = rng.random_range(0..5);
3734
3735                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3736
3737                self.expand_excerpts(
3738                    excerpts.iter().cloned(),
3739                    line_count,
3740                    ExpandExcerptDirection::UpAndDown,
3741                    cx,
3742                );
3743                continue;
3744            }
3745
3746            let excerpt_ids = self.excerpt_ids();
3747            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3748                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3749                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3750                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3751                    let buffer = buffers.last().unwrap().read(cx);
3752                    log::info!(
3753                        "Creating new buffer {} with text: {:?}",
3754                        buffer.remote_id(),
3755                        buffer.text()
3756                    );
3757                    buffers.last().unwrap().clone()
3758                } else {
3759                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3760                };
3761
3762                let buffer = buffer_handle.read(cx);
3763                let buffer_text = buffer.text();
3764                let ranges = (0..rng.random_range(0..5))
3765                    .map(|_| {
3766                        let end_ix =
3767                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3768                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3769                        ExcerptRange::new(start_ix..end_ix)
3770                    })
3771                    .collect::<Vec<_>>();
3772                log::info!(
3773                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3774                    buffer_handle.read(cx).remote_id(),
3775                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3776                    ranges
3777                        .iter()
3778                        .map(|r| &buffer_text[r.context.clone()])
3779                        .collect::<Vec<_>>()
3780                );
3781
3782                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3783                log::info!("Inserted with ids: {:?}", excerpt_id);
3784            } else {
3785                let remove_count = rng.random_range(1..=excerpt_ids.len());
3786                let mut excerpts_to_remove = excerpt_ids
3787                    .choose_multiple(rng, remove_count)
3788                    .cloned()
3789                    .collect::<Vec<_>>();
3790                let snapshot = self.snapshot.borrow();
3791                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3792                drop(snapshot);
3793                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3794                self.remove_excerpts(excerpts_to_remove, cx);
3795            }
3796        }
3797    }
3798
3799    pub fn randomly_mutate(
3800        &mut self,
3801        rng: &mut impl rand::Rng,
3802        mutation_count: usize,
3803        cx: &mut Context<Self>,
3804    ) {
3805        use rand::prelude::*;
3806
3807        if rng.random_bool(0.7) || self.singleton {
3808            let buffer = self
3809                .buffers
3810                .values()
3811                .choose(rng)
3812                .map(|state| state.buffer.clone());
3813
3814            if let Some(buffer) = buffer {
3815                buffer.update(cx, |buffer, cx| {
3816                    if rng.random() {
3817                        buffer.randomly_edit(rng, mutation_count, cx);
3818                    } else {
3819                        buffer.randomly_undo_redo(rng, cx);
3820                    }
3821                });
3822            } else {
3823                self.randomly_edit(rng, mutation_count, cx);
3824            }
3825        } else {
3826            self.randomly_edit_excerpts(rng, mutation_count, cx);
3827        }
3828
3829        self.check_invariants(cx);
3830    }
3831
3832    fn check_invariants(&self, cx: &App) {
3833        self.read(cx).check_invariants();
3834    }
3835}
3836
3837impl EventEmitter<Event> for MultiBuffer {}
3838
3839impl MultiBufferSnapshot {
3840    pub fn text(&self) -> String {
3841        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3842            .map(|chunk| chunk.text)
3843            .collect()
3844    }
3845
3846    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3847        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3848            .flat_map(|c| c.chars().rev())
3849    }
3850
3851    fn reversed_chunks_in_range(
3852        &self,
3853        range: Range<MultiBufferOffset>,
3854    ) -> ReversedMultiBufferChunks<'_> {
3855        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3856        cursor.seek(&range.end);
3857        let current_chunks = cursor.region().as_ref().map(|region| {
3858            let start_overshoot = range.start.saturating_sub(region.range.start);
3859            let end_overshoot = range.end - region.range.start;
3860            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3861            let start = region.buffer_range.start + start_overshoot;
3862            region.buffer.reversed_chunks_in_range(start..end)
3863        });
3864        ReversedMultiBufferChunks {
3865            cursor,
3866            current_chunks,
3867            start: range.start,
3868            offset: range.end,
3869        }
3870    }
3871
3872    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3873        let offset = position.to_offset(self);
3874        self.text_for_range(offset..self.len())
3875            .flat_map(|chunk| chunk.chars())
3876    }
3877
3878    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3879        self.chunks(range, false).map(|chunk| chunk.text)
3880    }
3881
3882    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3883        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3884            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3885    }
3886
3887    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3888    where
3889        T: ToOffset,
3890    {
3891        let position = position.to_offset(self);
3892        position == self.clip_offset(position, Bias::Left)
3893            && self
3894                .bytes_in_range(position..self.len())
3895                .flatten()
3896                .copied()
3897                .take(needle.len())
3898                .eq(needle.bytes())
3899    }
3900
3901    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3902        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3903    }
3904
3905    pub fn diff_hunks_in_range<T: ToPoint>(
3906        &self,
3907        range: Range<T>,
3908    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3909        let query_range = range.start.to_point(self)..range.end.to_point(self);
3910        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3911            let diff = self.diffs.get(&buffer.remote_id())?;
3912            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3913                if diff.is_inverted {
3914                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3915                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3916                    Box::new(
3917                        diff.hunks_intersecting_base_text_range(
3918                            buffer_start..buffer_end,
3919                            diff.original_buffer_snapshot(),
3920                        )
3921                        .map(move |hunk| (hunk, buffer, true)),
3922                    )
3923                } else {
3924                    let buffer_start = buffer.anchor_before(buffer_range.start);
3925                    let buffer_end = buffer.anchor_after(buffer_range.end);
3926                    Box::new(
3927                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3928                            .map(move |hunk| (hunk, buffer, false)),
3929                    )
3930                };
3931            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3932                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3933                    return None;
3934                }
3935                let range = if is_inverted {
3936                    hunk.diff_base_byte_range.to_point(&buffer)
3937                } else {
3938                    hunk.range.clone()
3939                };
3940                Some((range, (hunk, is_inverted)))
3941            }))
3942        })
3943        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3944            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3945            {
3946                return None;
3947            }
3948            let end_row = if range.end.column == 0 {
3949                range.end.row
3950            } else {
3951                range.end.row + 1
3952            };
3953
3954            let word_diffs =
3955                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3956                    .then(|| {
3957                        let mut word_diffs = Vec::new();
3958
3959                        if self.show_deleted_hunks || is_inverted {
3960                            let hunk_start_offset = if is_inverted {
3961                                Anchor::in_buffer(
3962                                    excerpt.id,
3963                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3964                                )
3965                                .to_offset(self)
3966                            } else {
3967                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3968                                    .to_offset(self)
3969                            };
3970
3971                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3972                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3973                            }));
3974                        }
3975
3976                        if !is_inverted {
3977                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3978                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3979                            }));
3980                        }
3981                        word_diffs
3982                    })
3983                    .unwrap_or_default();
3984
3985            let buffer_range = if is_inverted {
3986                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3987                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3988            } else {
3989                hunk.buffer_range.clone()
3990            };
3991            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3992                DiffHunkStatusKind::Deleted
3993            } else if hunk.diff_base_byte_range.is_empty() {
3994                DiffHunkStatusKind::Added
3995            } else {
3996                DiffHunkStatusKind::Modified
3997            };
3998            Some(MultiBufferDiffHunk {
3999                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4000                buffer_id: excerpt.buffer_id,
4001                excerpt_id: excerpt.id,
4002                buffer_range,
4003                word_diffs,
4004                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4005                    ..BufferOffset(hunk.diff_base_byte_range.end),
4006                status: DiffHunkStatus {
4007                    kind: status_kind,
4008                    secondary: hunk.secondary_status,
4009                },
4010            })
4011        })
4012    }
4013
4014    fn excerpts_for_range<T: ToOffset>(
4015        &self,
4016        range: Range<T>,
4017    ) -> impl Iterator<Item = &Excerpt> + '_ {
4018        let range = range.start.to_offset(self)..range.end.to_offset(self);
4019        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4020        cursor.seek(&range.start);
4021        std::iter::from_fn(move || {
4022            let region = cursor.region()?;
4023            if region.range.start > range.end
4024                || region.range.start == range.end && region.range.start > range.start
4025            {
4026                return None;
4027            }
4028            let excerpt = region.excerpt;
4029            cursor.next_excerpt_forwards();
4030            Some(excerpt)
4031        })
4032    }
4033
4034    pub fn excerpt_ids_for_range<T: ToOffset>(
4035        &self,
4036        range: Range<T>,
4037    ) -> impl Iterator<Item = ExcerptId> + '_ {
4038        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4039    }
4040
4041    pub fn buffer_ids_for_range<T: ToOffset>(
4042        &self,
4043        range: Range<T>,
4044    ) -> impl Iterator<Item = BufferId> + '_ {
4045        self.excerpts_for_range(range)
4046            .map(|excerpt| excerpt.buffer_id)
4047    }
4048
4049    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4050        &self,
4051        ranges: impl Iterator<Item = Range<T>>,
4052    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4053        ranges.flat_map(|range| {
4054            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4055                .into_iter()
4056        })
4057    }
4058
4059    pub fn range_to_buffer_ranges<R, T>(
4060        &self,
4061        range: R,
4062    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4063    where
4064        R: RangeBounds<T>,
4065        T: ToOffset,
4066    {
4067        self.range_to_buffer_ranges_with_context(range)
4068            .into_iter()
4069            .map(|(buffer, range, id, _context)| (buffer, range, id))
4070            .collect()
4071    }
4072
4073    pub fn range_to_buffer_ranges_with_context<R, T>(
4074        &self,
4075        range: R,
4076    ) -> Vec<(
4077        &BufferSnapshot,
4078        Range<BufferOffset>,
4079        ExcerptId,
4080        Range<text::Anchor>,
4081    )>
4082    where
4083        R: RangeBounds<T>,
4084        T: ToOffset,
4085    {
4086        let start = match range.start_bound() {
4087            Bound::Included(start) => start.to_offset(self),
4088            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4089            Bound::Unbounded => MultiBufferOffset::ZERO,
4090        };
4091        let end_bound = match range.end_bound() {
4092            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4093            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4094            Bound::Unbounded => Bound::Unbounded,
4095        };
4096        let bounds = (Bound::Included(start), end_bound);
4097
4098        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4099        cursor.seek(&start);
4100
4101        let mut result: Vec<(
4102            &BufferSnapshot,
4103            Range<BufferOffset>,
4104            ExcerptId,
4105            Range<text::Anchor>,
4106        )> = Vec::new();
4107        while let Some(region) = cursor.region() {
4108            let dominated_by_end_bound = match end_bound {
4109                Bound::Included(end) => region.range.start > end,
4110                Bound::Excluded(end) => region.range.start >= end,
4111                Bound::Unbounded => false,
4112            };
4113            if dominated_by_end_bound {
4114                break;
4115            }
4116            if region.is_main_buffer {
4117                let start_overshoot = start.saturating_sub(region.range.start);
4118                let end_offset = match end_bound {
4119                    Bound::Included(end) | Bound::Excluded(end) => end,
4120                    Bound::Unbounded => region.range.end,
4121                };
4122                let end_overshoot = end_offset.saturating_sub(region.range.start);
4123                let start = region
4124                    .buffer_range
4125                    .end
4126                    .min(region.buffer_range.start + start_overshoot);
4127                let end = region
4128                    .buffer_range
4129                    .end
4130                    .min(region.buffer_range.start + end_overshoot);
4131                let context = region.excerpt.range.context.clone();
4132                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4133                    *excerpt_id == region.excerpt.id && prev_range.end == start
4134                }) {
4135                    prev.1.end = end;
4136                } else {
4137                    result.push((region.buffer, start..end, region.excerpt.id, context));
4138                }
4139            }
4140            cursor.next();
4141        }
4142
4143        if let Some(excerpt) = cursor.excerpt() {
4144            let dominated_by_prev_excerpt =
4145                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4146            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4147                let excerpt_position = self.len();
4148                if bounds.contains(&excerpt_position) {
4149                    let buffer_offset =
4150                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4151                    let context = excerpt.range.context.clone();
4152                    result.push((
4153                        &excerpt.buffer,
4154                        buffer_offset..buffer_offset,
4155                        excerpt.id,
4156                        context,
4157                    ));
4158                }
4159            }
4160        }
4161
4162        result
4163    }
4164
4165    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4166        &self,
4167        range: Range<T>,
4168    ) -> impl Iterator<
4169        Item = (
4170            &BufferSnapshot,
4171            Range<BufferOffset>,
4172            ExcerptId,
4173            Option<Anchor>,
4174        ),
4175    > + '_ {
4176        let start = range.start.to_offset(self);
4177        let end = range.end.to_offset(self);
4178
4179        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4180        cursor.seek(&start);
4181
4182        std::iter::from_fn(move || {
4183            let region = cursor.region()?;
4184            if region.range.start > end {
4185                return None;
4186            }
4187            let start_overshoot = start.saturating_sub(region.range.start);
4188            let end_overshoot = end.saturating_sub(region.range.start);
4189            let start = region
4190                .buffer_range
4191                .end
4192                .min(region.buffer_range.start + start_overshoot);
4193            let end = region
4194                .buffer_range
4195                .end
4196                .min(region.buffer_range.start + end_overshoot);
4197
4198            let region_excerpt_id = region.excerpt.id;
4199            let deleted_hunk_anchor = if region.is_main_buffer {
4200                None
4201            } else {
4202                Some(self.anchor_before(region.range.start))
4203            };
4204            let result = (
4205                region.buffer,
4206                start..end,
4207                region_excerpt_id,
4208                deleted_hunk_anchor,
4209            );
4210            cursor.next();
4211            Some(result)
4212        })
4213    }
4214
4215    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4216    /// coordinates.
4217    ///
4218    /// The given callback will be called for every excerpt intersecting the given range. It will
4219    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4220    /// The callback should return an iterator of metadata items from that buffer, each paired
4221    /// with a buffer range.
4222    ///
4223    /// The returned iterator yields each of these metadata items, paired with its range in
4224    /// multi-buffer coordinates.
4225    fn lift_buffer_metadata<'a, MBD, M, I>(
4226        &'a self,
4227        query_range: Range<MBD>,
4228        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4229    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4230    where
4231        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4232        MBD: MultiBufferDimension
4233            + Ord
4234            + Sub<Output = MBD::TextDimension>
4235            + ops::Add<MBD::TextDimension, Output = MBD>
4236            + ops::AddAssign<MBD::TextDimension>,
4237        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4238            + ops::Add<Output = MBD::TextDimension>
4239            + AddAssign<MBD::TextDimension>
4240            + Ord,
4241    {
4242        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4243        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4244
4245        // Find the excerpt and buffer offset where the given range ends.
4246        cursor.seek(&query_range.end);
4247        let mut range_end = None;
4248        while let Some(region) = cursor.region() {
4249            if region.is_main_buffer {
4250                let mut buffer_end = region.buffer_range.start;
4251                let overshoot = if query_range.end > region.range.start {
4252                    query_range.end - region.range.start
4253                } else {
4254                    <MBD::TextDimension>::default()
4255                };
4256                buffer_end = buffer_end + overshoot;
4257                range_end = Some((region.excerpt.id, buffer_end));
4258                break;
4259            }
4260            cursor.next();
4261        }
4262
4263        cursor.seek(&query_range.start);
4264
4265        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4266            && region.range.start > MBD::default()
4267        {
4268            cursor.prev()
4269        } else if let Some(region) = cursor.region()
4270            && region.is_main_buffer
4271            && region.diff_hunk_status.is_some()
4272        {
4273            cursor.prev();
4274            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4275                cursor.next();
4276            }
4277        }
4278
4279        iter::from_fn(move || {
4280            loop {
4281                let excerpt = cursor.excerpt()?;
4282
4283                // If we have already retrieved metadata for this excerpt, continue to use it.
4284                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4285                    .as_mut()
4286                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4287                {
4288                    Some(metadata)
4289                }
4290                // Otherwise, compute the intersection of the input range with the excerpt's range,
4291                // and retrieve the metadata for the resulting range.
4292                else {
4293                    let region = cursor.region()?;
4294                    let mut buffer_start;
4295                    if region.is_main_buffer {
4296                        buffer_start = region.buffer_range.start;
4297                        if query_range.start > region.range.start {
4298                            let overshoot = query_range.start - region.range.start;
4299                            buffer_start = buffer_start + overshoot;
4300                        }
4301                        buffer_start = buffer_start.min(region.buffer_range.end);
4302                    } else {
4303                        buffer_start = cursor.main_buffer_position()?;
4304                    };
4305                    let mut buffer_end = excerpt
4306                        .range
4307                        .context
4308                        .end
4309                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4310                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4311                        && excerpt.id == end_excerpt_id
4312                    {
4313                        buffer_end = buffer_end.min(end_buffer_offset);
4314                    }
4315
4316                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4317                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4318                    })
4319                };
4320
4321                // Visit each metadata item.
4322                if let Some((metadata_buffer_range, metadata)) =
4323                    metadata_iter.and_then(Iterator::next)
4324                {
4325                    // Find the multibuffer regions that contain the start and end of
4326                    // the metadata item's range.
4327                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4328                        while let Some(region) = cursor.region() {
4329                            if (region.is_main_buffer
4330                                && (region.buffer_range.end >= metadata_buffer_range.start
4331                                    || cursor.is_at_end_of_excerpt()))
4332                                || (!region.is_main_buffer
4333                                    && region.buffer_range.start == metadata_buffer_range.start)
4334                            {
4335                                break;
4336                            }
4337                            cursor.next();
4338                        }
4339                    }
4340                    let start_region = cursor.region()?.clone();
4341                    while let Some(region) = cursor.region() {
4342                        if region.is_main_buffer
4343                            && (region.buffer_range.end > metadata_buffer_range.end
4344                                || cursor.is_at_end_of_excerpt())
4345                        {
4346                            break;
4347                        }
4348                        cursor.next();
4349                    }
4350                    let end_region = cursor.region();
4351
4352                    // Convert the metadata item's range into multibuffer coordinates.
4353                    let mut start_position = start_region.range.start;
4354                    let region_buffer_start = start_region.buffer_range.start;
4355                    if start_region.is_main_buffer
4356                        && metadata_buffer_range.start > region_buffer_start
4357                    {
4358                        start_position =
4359                            start_position + (metadata_buffer_range.start - region_buffer_start);
4360                        start_position = start_position.min(start_region.range.end);
4361                    }
4362
4363                    let mut end_position = self.max_position();
4364                    if let Some(end_region) = &end_region {
4365                        end_position = end_region.range.start;
4366                        debug_assert!(end_region.is_main_buffer);
4367                        let region_buffer_start = end_region.buffer_range.start;
4368                        if metadata_buffer_range.end > region_buffer_start {
4369                            end_position =
4370                                end_position + (metadata_buffer_range.end - region_buffer_start);
4371                        }
4372                        end_position = end_position.min(end_region.range.end);
4373                    }
4374
4375                    if start_position <= query_range.end && end_position >= query_range.start {
4376                        return Some((start_position..end_position, metadata, excerpt));
4377                    }
4378                }
4379                // When there are no more metadata items for this excerpt, move to the next excerpt.
4380                else {
4381                    current_excerpt_metadata.take();
4382                    if let Some((end_excerpt_id, _)) = range_end
4383                        && excerpt.id == end_excerpt_id
4384                    {
4385                        return None;
4386                    }
4387                    cursor.next_excerpt_forwards();
4388                }
4389            }
4390        })
4391    }
4392
4393    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4394        let offset = position.to_offset(self);
4395
4396        let mut cursor = self
4397            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4398            );
4399        cursor.seek(&DimensionPair {
4400            key: offset,
4401            value: None,
4402        });
4403        cursor.seek_to_start_of_current_excerpt();
4404        let excerpt = cursor.excerpt()?;
4405
4406        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4407        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4408        let current_position = self
4409            .anchor_before(offset)
4410            .text_anchor
4411            .to_offset(&excerpt.buffer);
4412
4413        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4414            if diff.is_inverted {
4415                for hunk in diff.hunks_intersecting_base_text_range_rev(
4416                    excerpt_start..excerpt_end,
4417                    diff.original_buffer_snapshot(),
4418                ) {
4419                    if hunk.diff_base_byte_range.end >= current_position {
4420                        continue;
4421                    }
4422                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4423                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4424                    return Some(MultiBufferRow(start.row));
4425                }
4426            } else {
4427                let excerpt_end = excerpt
4428                    .buffer
4429                    .anchor_before(excerpt_end.min(current_position));
4430                for hunk in diff.hunks_intersecting_range_rev(
4431                    excerpt.range.context.start..excerpt_end,
4432                    &excerpt.buffer,
4433                ) {
4434                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4435                    if hunk_end >= current_position {
4436                        continue;
4437                    }
4438                    let start =
4439                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4440                    return Some(MultiBufferRow(start.row));
4441                }
4442            }
4443        }
4444
4445        loop {
4446            cursor.prev_excerpt();
4447            let excerpt = cursor.excerpt()?;
4448
4449            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4450                continue;
4451            };
4452            if diff.is_inverted {
4453                let Some(hunk) = diff
4454                    .hunks_intersecting_base_text_range_rev(
4455                        excerpt.range.context.to_offset(&excerpt.buffer),
4456                        diff.original_buffer_snapshot(),
4457                    )
4458                    .next()
4459                else {
4460                    continue;
4461                };
4462                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4463                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4464                return Some(MultiBufferRow(start.row));
4465            } else {
4466                let Some(hunk) = diff
4467                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4468                    .next()
4469                else {
4470                    continue;
4471                };
4472                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4473                return Some(MultiBufferRow(start.row));
4474            }
4475        }
4476    }
4477
4478    pub fn has_diff_hunks(&self) -> bool {
4479        self.diffs.values().any(|diff| !diff.is_empty())
4480    }
4481
4482    pub fn is_inside_word<T: ToOffset>(
4483        &self,
4484        position: T,
4485        scope_context: Option<CharScopeContext>,
4486    ) -> bool {
4487        let position = position.to_offset(self);
4488        let classifier = self
4489            .char_classifier_at(position)
4490            .scope_context(scope_context);
4491        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4492        let prev_char_kind = self
4493            .reversed_chars_at(position)
4494            .next()
4495            .map(|c| classifier.kind(c));
4496        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4497    }
4498
4499    pub fn surrounding_word<T: ToOffset>(
4500        &self,
4501        start: T,
4502        scope_context: Option<CharScopeContext>,
4503    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4504        let mut start = start.to_offset(self);
4505        let mut end = start;
4506        let mut next_chars = self.chars_at(start).peekable();
4507        let mut prev_chars = self.reversed_chars_at(start).peekable();
4508
4509        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4510
4511        let word_kind = cmp::max(
4512            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4513            next_chars.peek().copied().map(|c| classifier.kind(c)),
4514        );
4515
4516        for ch in prev_chars {
4517            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4518                start -= ch.len_utf8();
4519            } else {
4520                break;
4521            }
4522        }
4523
4524        for ch in next_chars {
4525            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4526                end += ch.len_utf8();
4527            } else {
4528                break;
4529            }
4530        }
4531
4532        (start..end, word_kind)
4533    }
4534
4535    pub fn char_kind_before<T: ToOffset>(
4536        &self,
4537        start: T,
4538        scope_context: Option<CharScopeContext>,
4539    ) -> Option<CharKind> {
4540        let start = start.to_offset(self);
4541        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4542        self.reversed_chars_at(start)
4543            .next()
4544            .map(|ch| classifier.kind(ch))
4545    }
4546
4547    pub fn is_singleton(&self) -> bool {
4548        self.singleton
4549    }
4550
4551    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4552        if self.singleton {
4553            self.excerpts
4554                .iter()
4555                .next()
4556                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4557        } else {
4558            None
4559        }
4560    }
4561
4562    pub fn len(&self) -> MultiBufferOffset {
4563        self.diff_transforms.summary().output.len
4564    }
4565
4566    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4567        MBD::from_summary(&self.text_summary())
4568    }
4569
4570    pub fn is_empty(&self) -> bool {
4571        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4572    }
4573
4574    pub fn widest_line_number(&self) -> u32 {
4575        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4576        self.excerpts.summary().widest_line_number + 1
4577    }
4578
4579    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4580        let range = range.start.to_offset(self)..range.end.to_offset(self);
4581        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4582        excerpts.seek(&range.start);
4583
4584        let mut chunk;
4585        let mut has_trailing_newline;
4586        let excerpt_bytes;
4587        if let Some(region) = excerpts.region() {
4588            let mut bytes = region.buffer.bytes_in_range(
4589                region.buffer_range.start + (range.start - region.range.start)
4590                    ..(region.buffer_range.start + (range.end - region.range.start))
4591                        .min(region.buffer_range.end),
4592            );
4593            chunk = bytes.next().unwrap_or(&[][..]);
4594            excerpt_bytes = Some(bytes);
4595            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4596            if chunk.is_empty() && has_trailing_newline {
4597                chunk = b"\n";
4598                has_trailing_newline = false;
4599            }
4600        } else {
4601            chunk = &[][..];
4602            excerpt_bytes = None;
4603            has_trailing_newline = false;
4604        };
4605
4606        MultiBufferBytes {
4607            range,
4608            cursor: excerpts,
4609            excerpt_bytes,
4610            has_trailing_newline,
4611            chunk,
4612        }
4613    }
4614
4615    pub fn reversed_bytes_in_range<T: ToOffset>(
4616        &self,
4617        range: Range<T>,
4618    ) -> ReversedMultiBufferBytes<'_> {
4619        let range = range.start.to_offset(self)..range.end.to_offset(self);
4620        let mut chunks = self.reversed_chunks_in_range(range.clone());
4621        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4622        ReversedMultiBufferBytes {
4623            range,
4624            chunks,
4625            chunk,
4626        }
4627    }
4628
4629    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4630        let mut cursor = self.cursor::<Point, Point>();
4631        cursor.seek(&Point::new(start_row.0, 0));
4632        let mut result = MultiBufferRows {
4633            point: Point::new(0, 0),
4634            is_empty: self.excerpts.is_empty(),
4635            is_singleton: self.is_singleton(),
4636            cursor,
4637        };
4638        result.seek(start_row);
4639        result
4640    }
4641
4642    pub fn chunks<T: ToOffset>(
4643        &self,
4644        range: Range<T>,
4645        language_aware: bool,
4646    ) -> MultiBufferChunks<'_> {
4647        let mut chunks = MultiBufferChunks {
4648            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4649                ..ExcerptDimension(MultiBufferOffset::ZERO),
4650            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4651            excerpts: self.excerpts.cursor(()),
4652            diff_transforms: self.diff_transforms.cursor(()),
4653            diffs: &self.diffs,
4654            diff_base_chunks: None,
4655            excerpt_chunks: None,
4656            buffer_chunk: None,
4657            language_aware,
4658        };
4659        let range = range.start.to_offset(self)..range.end.to_offset(self);
4660        chunks.seek(range);
4661        chunks
4662    }
4663
4664    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4665        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4666    }
4667
4668    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4669        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4670    }
4671
4672    pub fn clip_offset_utf16(
4673        &self,
4674        offset: MultiBufferOffsetUtf16,
4675        bias: Bias,
4676    ) -> MultiBufferOffsetUtf16 {
4677        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4678    }
4679
4680    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4681        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4682            buffer.clip_point_utf16(Unclipped(point), bias)
4683        })
4684    }
4685
4686    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4687        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4688    }
4689
4690    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4691        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4692    }
4693
4694    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4695        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4696    }
4697
4698    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4699        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4700    }
4701
4702    #[instrument(skip_all)]
4703    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4704        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4705    }
4706
4707    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4708        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4709    }
4710
4711    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4712        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4713    }
4714
4715    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4716        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4717    }
4718
4719    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4720        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4721    }
4722
4723    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4724        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4725    }
4726
4727    fn clip_dimension<MBD, BD>(
4728        &self,
4729        position: MBD,
4730        bias: Bias,
4731        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4732    ) -> MBD
4733    where
4734        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4735        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4736    {
4737        let mut cursor = self.cursor::<MBD, BD>();
4738        cursor.seek(&position);
4739        if let Some(region) = cursor.region() {
4740            if position >= region.range.end {
4741                return region.range.end;
4742            }
4743            let overshoot = position - region.range.start;
4744            let mut buffer_position = region.buffer_range.start;
4745            buffer_position += overshoot;
4746            let clipped_buffer_position =
4747                clip_buffer_position(region.buffer, buffer_position, bias);
4748            let mut position = region.range.start;
4749            position += clipped_buffer_position - region.buffer_range.start;
4750            position
4751        } else {
4752            self.max_position()
4753        }
4754    }
4755
4756    #[instrument(skip_all)]
4757    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4758        &self,
4759        key: MBR1,
4760        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4761    ) -> MBR2
4762    where
4763        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4764        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4765        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4766        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4767    {
4768        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4769        cursor.seek(&DimensionPair { key, value: None });
4770        if let Some(region) = cursor.region() {
4771            if key >= region.range.end.key {
4772                return region.range.end.value.unwrap();
4773            }
4774            let start_key = region.range.start.key;
4775            let start_value = region.range.start.value.unwrap();
4776            let buffer_start_key = region.buffer_range.start.key;
4777            let buffer_start_value = region.buffer_range.start.value.unwrap();
4778            let mut buffer_key = buffer_start_key;
4779            buffer_key += key - start_key;
4780            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4781            let mut result = start_value;
4782            result += buffer_value - buffer_start_value;
4783            result
4784        } else {
4785            self.max_position()
4786        }
4787    }
4788
4789    pub fn point_to_buffer_offset<T: ToOffset>(
4790        &self,
4791        point: T,
4792    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4793        let offset = point.to_offset(self);
4794        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4795        cursor.seek(&offset);
4796        let region = cursor.region()?;
4797        let overshoot = offset - region.range.start;
4798        let buffer_offset = region.buffer_range.start + overshoot;
4799        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4800            && region.has_trailing_newline
4801            && !region.is_main_buffer
4802        {
4803            let main_buffer_position = cursor.main_buffer_position()?;
4804            let buffer_snapshot = &cursor.excerpt()?.buffer;
4805            return Some((buffer_snapshot, main_buffer_position));
4806        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4807            return None;
4808        }
4809        Some((region.buffer, buffer_offset))
4810    }
4811
4812    pub fn point_to_buffer_point(
4813        &self,
4814        point: Point,
4815    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4816        let mut cursor = self.cursor::<Point, Point>();
4817        cursor.seek(&point);
4818        let region = cursor.region()?;
4819        let overshoot = point - region.range.start;
4820        let buffer_point = region.buffer_range.start + overshoot;
4821        let excerpt = cursor.excerpt()?;
4822        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4823            && region.has_trailing_newline
4824            && !region.is_main_buffer
4825        {
4826            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4827        } else if buffer_point > region.buffer.max_point() {
4828            return None;
4829        }
4830        Some((region.buffer, buffer_point, excerpt.id))
4831    }
4832
4833    pub fn suggested_indents(
4834        &self,
4835        rows: impl IntoIterator<Item = u32>,
4836        cx: &App,
4837    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4838        let mut result = BTreeMap::new();
4839        self.suggested_indents_callback(
4840            rows,
4841            |row, indent| {
4842                result.insert(row, indent);
4843                ControlFlow::Continue(())
4844            },
4845            cx,
4846        );
4847        result
4848    }
4849
4850    // move this to be a generator once those are a thing
4851    pub fn suggested_indents_callback(
4852        &self,
4853        rows: impl IntoIterator<Item = u32>,
4854        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4855        cx: &App,
4856    ) {
4857        let mut rows_for_excerpt = Vec::new();
4858        let mut cursor = self.cursor::<Point, Point>();
4859        let mut rows = rows.into_iter().peekable();
4860        let mut prev_row = u32::MAX;
4861        let mut prev_language_indent_size = IndentSize::default();
4862
4863        while let Some(row) = rows.next() {
4864            cursor.seek(&Point::new(row, 0));
4865            let Some(region) = cursor.region() else {
4866                continue;
4867            };
4868
4869            // Retrieve the language and indent size once for each disjoint region being indented.
4870            let single_indent_size = if row.saturating_sub(1) == prev_row {
4871                prev_language_indent_size
4872            } else {
4873                region
4874                    .buffer
4875                    .language_indent_size_at(Point::new(row, 0), cx)
4876            };
4877            prev_language_indent_size = single_indent_size;
4878            prev_row = row;
4879
4880            let start_buffer_row = region.buffer_range.start.row;
4881            let start_multibuffer_row = region.range.start.row;
4882            let end_multibuffer_row = region.range.end.row;
4883
4884            rows_for_excerpt.push(row);
4885            while let Some(next_row) = rows.peek().copied() {
4886                if end_multibuffer_row > next_row {
4887                    rows_for_excerpt.push(next_row);
4888                    rows.next();
4889                } else {
4890                    break;
4891                }
4892            }
4893
4894            let buffer_rows = rows_for_excerpt
4895                .drain(..)
4896                .map(|row| start_buffer_row + row - start_multibuffer_row);
4897            let buffer_indents = region
4898                .buffer
4899                .suggested_indents(buffer_rows, single_indent_size);
4900            for (row, indent) in buffer_indents {
4901                if cb(
4902                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4903                    indent,
4904                )
4905                .is_break()
4906                {
4907                    return;
4908                }
4909            }
4910        }
4911    }
4912
4913    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4914        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4915            let mut size = buffer.indent_size_for_line(range.start.row);
4916            size.len = size
4917                .len
4918                .min(range.end.column)
4919                .saturating_sub(range.start.column);
4920            size
4921        } else {
4922            IndentSize::spaces(0)
4923        }
4924    }
4925
4926    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4927        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4928            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4929        } else {
4930            LineIndent::spaces(0)
4931        }
4932    }
4933
4934    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4935        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4936
4937        if self.language_settings(cx).extend_comment_on_newline
4938            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4939        {
4940            let delimiters = language_scope.line_comment_prefixes();
4941            for delimiter in delimiters {
4942                if *self
4943                    .chars_at(Point::new(row.0, indent.len() as u32))
4944                    .take(delimiter.chars().count())
4945                    .collect::<String>()
4946                    .as_str()
4947                    == **delimiter
4948                {
4949                    indent.push_str(delimiter);
4950                    break;
4951                }
4952            }
4953        }
4954
4955        indent
4956    }
4957
4958    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4959    where
4960        T: ToOffset,
4961    {
4962        for char in self.reversed_chars_at(position) {
4963            if !char.is_whitespace() {
4964                return false;
4965            }
4966            if char == '\n' {
4967                return true;
4968            }
4969        }
4970        true
4971    }
4972
4973    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4974        while row.0 > 0 {
4975            row.0 -= 1;
4976            if !self.is_line_blank(row) {
4977                return Some(row);
4978            }
4979        }
4980        None
4981    }
4982
4983    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4984        if let Some((_, range)) = self.buffer_line_for_row(row) {
4985            range.end.column - range.start.column
4986        } else {
4987            0
4988        }
4989    }
4990
4991    pub fn buffer_line_for_row(
4992        &self,
4993        row: MultiBufferRow,
4994    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4995        let mut cursor = self.cursor::<Point, Point>();
4996        let point = Point::new(row.0, 0);
4997        cursor.seek(&point);
4998        let region = cursor.region()?;
4999        let overshoot = point.min(region.range.end) - region.range.start;
5000        let buffer_point = region.buffer_range.start + overshoot;
5001        if buffer_point.row > region.buffer_range.end.row {
5002            return None;
5003        }
5004        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5005        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5006            .min(region.buffer_range.end);
5007        Some((region.buffer, line_start..line_end))
5008    }
5009
5010    pub fn max_point(&self) -> Point {
5011        self.text_summary().lines
5012    }
5013
5014    pub fn max_row(&self) -> MultiBufferRow {
5015        MultiBufferRow(self.text_summary().lines.row)
5016    }
5017
5018    pub fn text_summary(&self) -> MBTextSummary {
5019        self.diff_transforms.summary().output
5020    }
5021
5022    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5023    where
5024        MBD: MultiBufferDimension + AddAssign,
5025        O: ToOffset,
5026    {
5027        let range = range.start.to_offset(self)..range.end.to_offset(self);
5028        let mut cursor = self
5029            .diff_transforms
5030            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5031        cursor.seek(&range.start, Bias::Right);
5032
5033        let Some(first_transform) = cursor.item() else {
5034            return MBD::from_summary(&MBTextSummary::default());
5035        };
5036
5037        let diff_transform_start = cursor.start().0;
5038        let diff_transform_end = cursor.end().0;
5039        let diff_start = range.start;
5040        let start_overshoot = diff_start - diff_transform_start;
5041        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5042
5043        let mut result = match first_transform {
5044            DiffTransform::BufferContent { .. } => {
5045                let excerpt_start = cursor.start().1 + start_overshoot;
5046                let excerpt_end = cursor.start().1 + end_overshoot;
5047                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5048            }
5049            DiffTransform::DeletedHunk {
5050                buffer_id,
5051                base_text_byte_range,
5052                has_trailing_newline,
5053                ..
5054            } => {
5055                let buffer_start = base_text_byte_range.start + start_overshoot;
5056                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5057                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5058                    panic!("{:?} is in non-existent deleted hunk", range.start)
5059                };
5060
5061                let include_trailing_newline =
5062                    *has_trailing_newline && range.end >= diff_transform_end;
5063                if include_trailing_newline {
5064                    buffer_end -= 1;
5065                }
5066
5067                let mut summary = base_text
5068                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5069
5070                if include_trailing_newline {
5071                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5072                        &TextSummary::newline(),
5073                    ))
5074                }
5075
5076                let mut result = MBD::default();
5077                result.add_text_dim(&summary);
5078                result
5079            }
5080        };
5081        if range.end < diff_transform_end {
5082            return result;
5083        }
5084
5085        cursor.next();
5086        result.add_mb_text_summary(
5087            &cursor
5088                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5089                .0,
5090        );
5091
5092        let Some(last_transform) = cursor.item() else {
5093            return result;
5094        };
5095
5096        let overshoot = range.end - cursor.start().0;
5097        let suffix = match last_transform {
5098            DiffTransform::BufferContent { .. } => {
5099                let end = cursor.start().1 + overshoot;
5100                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5101            }
5102            DiffTransform::DeletedHunk {
5103                base_text_byte_range,
5104                buffer_id,
5105                has_trailing_newline,
5106                ..
5107            } => {
5108                let buffer_end = base_text_byte_range.start + overshoot;
5109                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5110                    panic!("{:?} is in non-existent deleted hunk", range.end)
5111                };
5112
5113                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5114                    base_text_byte_range.start..buffer_end,
5115                );
5116                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5117                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5118                        &TextSummary::from("\n"),
5119                    ))
5120                }
5121
5122                let mut result = MBD::default();
5123                result.add_text_dim(&suffix);
5124                result
5125            }
5126        };
5127
5128        result += suffix;
5129        result
5130    }
5131
5132    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5133    where
5134        MBD: MultiBufferDimension + AddAssign,
5135    {
5136        let mut summary = MBD::default();
5137        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5138        cursor.seek(&range.start, Bias::Right);
5139        if let Some(excerpt) = cursor.item() {
5140            let mut end_before_newline = cursor.end();
5141            if excerpt.has_trailing_newline {
5142                end_before_newline -= 1;
5143            }
5144
5145            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5146            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5147            let end_in_excerpt =
5148                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5149            summary.add_text_dim(
5150                &excerpt
5151                    .buffer
5152                    .text_summary_for_range::<MBD::TextDimension, _>(
5153                        start_in_excerpt..end_in_excerpt,
5154                    ),
5155            );
5156
5157            if range.end > end_before_newline {
5158                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5159            }
5160
5161            cursor.next();
5162        }
5163
5164        if range.end > *cursor.start() {
5165            summary += cursor
5166                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5167                .0;
5168            if let Some(excerpt) = cursor.item() {
5169                range.end = cmp::max(*cursor.start(), range.end);
5170
5171                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5172                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5173                summary.add_text_dim(
5174                    &excerpt
5175                        .buffer
5176                        .text_summary_for_range::<MBD::TextDimension, _>(
5177                            excerpt_start..end_in_excerpt,
5178                        ),
5179                );
5180            }
5181        }
5182
5183        summary
5184    }
5185
5186    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5187    where
5188        MBD: MultiBufferDimension
5189            + Ord
5190            + Sub<Output = MBD::TextDimension>
5191            + Sub<MBD::TextDimension, Output = MBD>
5192            + AddAssign<MBD::TextDimension>
5193            + Add<MBD::TextDimension, Output = MBD>,
5194        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5195    {
5196        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5197        let locator = self.excerpt_locator_for_id(excerpt_id);
5198        let (start, _, mut item) = self
5199            .excerpts
5200            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5201        let mut start = MBD::from_summary(&start.text);
5202        if item.is_none() && excerpt_id == ExcerptId::max() {
5203            item = self.excerpts.last();
5204            if let Some(last_summary) = self.excerpts.last_summary() {
5205                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5206            }
5207        }
5208
5209        if self.diff_transforms.is_empty() {
5210            let excerpt_start_position = ExcerptDimension(start);
5211            if let Some(excerpt) = item {
5212                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5213                    return excerpt_start_position.0;
5214                }
5215                let excerpt_buffer_start = excerpt
5216                    .range
5217                    .context
5218                    .start
5219                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5220                let excerpt_buffer_end = excerpt
5221                    .range
5222                    .context
5223                    .end
5224                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5225                let buffer_summary = anchor
5226                    .text_anchor
5227                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5228                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5229                let mut position = excerpt_start_position;
5230                if summary > excerpt_buffer_start {
5231                    position += summary - excerpt_buffer_start;
5232                }
5233
5234                position.0
5235            } else {
5236                excerpt_start_position.0
5237            }
5238        } else {
5239            let mut diff_transforms_cursor = self
5240                .diff_transforms
5241                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5242            diff_transforms_cursor.next();
5243
5244            let excerpt_start_position = ExcerptDimension(start);
5245            if let Some(excerpt) = item {
5246                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5247                    return self.resolve_summary_for_anchor(
5248                        &Anchor::min(),
5249                        excerpt_start_position,
5250                        &mut diff_transforms_cursor,
5251                    );
5252                }
5253                let excerpt_buffer_start = excerpt
5254                    .range
5255                    .context
5256                    .start
5257                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5258                let excerpt_buffer_end = excerpt
5259                    .range
5260                    .context
5261                    .end
5262                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5263                let buffer_summary = anchor
5264                    .text_anchor
5265                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5266                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5267                let mut position = excerpt_start_position;
5268                if summary > excerpt_buffer_start {
5269                    position += summary - excerpt_buffer_start;
5270                }
5271
5272                if diff_transforms_cursor.start().0 < position {
5273                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5274                }
5275                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5276            } else {
5277                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5278                self.resolve_summary_for_anchor(
5279                    &Anchor::max(),
5280                    excerpt_start_position,
5281                    &mut diff_transforms_cursor,
5282                )
5283            }
5284        }
5285    }
5286
5287    fn resolve_summary_for_anchor<MBD>(
5288        &self,
5289        anchor: &Anchor,
5290        excerpt_position: ExcerptDimension<MBD>,
5291        diff_transforms: &mut Cursor<
5292            DiffTransform,
5293            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5294        >,
5295    ) -> MBD
5296    where
5297        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5298    {
5299        loop {
5300            let transform_end_position = diff_transforms.end().0;
5301            let at_transform_end =
5302                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5303            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5304                diff_transforms.next();
5305                continue;
5306            }
5307
5308            let mut position = diff_transforms.start().1;
5309            match diff_transforms.item() {
5310                Some(DiffTransform::DeletedHunk {
5311                    buffer_id,
5312                    base_text_byte_range,
5313                    ..
5314                }) => {
5315                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5316                        && let Some(base_text) =
5317                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5318                        && diff_base_anchor.is_valid(&base_text)
5319                    {
5320                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5321                        if base_text_offset >= base_text_byte_range.start
5322                            && base_text_offset <= base_text_byte_range.end
5323                        {
5324                            let position_in_hunk = base_text
5325                                .text_summary_for_range::<MBD::TextDimension, _>(
5326                                    base_text_byte_range.start..base_text_offset,
5327                                );
5328                            position.0.add_text_dim(&position_in_hunk);
5329                        } else if at_transform_end {
5330                            diff_transforms.next();
5331                            continue;
5332                        }
5333                    }
5334                }
5335                _ => {
5336                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5337                        diff_transforms.next();
5338                        continue;
5339                    }
5340                    let overshoot = excerpt_position - diff_transforms.start().0;
5341                    position += overshoot;
5342                }
5343            }
5344
5345            return position.0;
5346        }
5347    }
5348
5349    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5350        let mut cursor = self
5351            .excerpts
5352            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5353        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5354
5355        cursor.seek(&Some(locator), Bias::Left);
5356        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5357            cursor.prev();
5358        }
5359
5360        let mut position = cursor.start().1;
5361        if let Some(excerpt) = cursor.item()
5362            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5363        {
5364            let excerpt_buffer_start = excerpt
5365                .buffer
5366                .offset_for_anchor(&excerpt.range.context.start);
5367            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5368            let buffer_position = cmp::min(
5369                excerpt_buffer_end,
5370                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5371            );
5372            if buffer_position > excerpt_buffer_start {
5373                position += buffer_position - excerpt_buffer_start;
5374            }
5375        }
5376        position
5377    }
5378
5379    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5380        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5381            excerpt_id = *replacement;
5382        }
5383        excerpt_id
5384    }
5385
5386    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5387    where
5388        MBD: MultiBufferDimension
5389            + Ord
5390            + Sub<Output = MBD::TextDimension>
5391            + AddAssign<MBD::TextDimension>,
5392        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5393        I: 'a + IntoIterator<Item = &'a Anchor>,
5394    {
5395        let mut anchors = anchors.into_iter().peekable();
5396        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5397        let mut diff_transforms_cursor = self
5398            .diff_transforms
5399            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5400        diff_transforms_cursor.next();
5401
5402        let mut summaries = Vec::new();
5403        while let Some(anchor) = anchors.peek() {
5404            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5405
5406            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5407                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5408            });
5409
5410            let locator = self.excerpt_locator_for_id(excerpt_id);
5411            cursor.seek_forward(locator, Bias::Left);
5412            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5413                cursor.prev();
5414            }
5415
5416            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5417            if let Some(excerpt) = cursor.item() {
5418                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5419                    let position = self.resolve_summary_for_anchor(
5420                        &Anchor::min(),
5421                        excerpt_start_position,
5422                        &mut diff_transforms_cursor,
5423                    );
5424                    summaries.extend(excerpt_anchors.map(|_| position));
5425                    continue;
5426                }
5427                let excerpt_buffer_start = excerpt
5428                    .range
5429                    .context
5430                    .start
5431                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5432                let excerpt_buffer_end = excerpt
5433                    .range
5434                    .context
5435                    .end
5436                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5437                for (buffer_summary, anchor) in excerpt
5438                    .buffer
5439                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5440                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5441                    )
5442                {
5443                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5444                    let mut position = excerpt_start_position;
5445                    if summary > excerpt_buffer_start {
5446                        position += summary - excerpt_buffer_start;
5447                    }
5448
5449                    if diff_transforms_cursor.start().0 < position {
5450                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5451                    }
5452
5453                    summaries.push(self.resolve_summary_for_anchor(
5454                        anchor,
5455                        position,
5456                        &mut diff_transforms_cursor,
5457                    ));
5458                }
5459            } else {
5460                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5461                let position = self.resolve_summary_for_anchor(
5462                    &Anchor::max(),
5463                    excerpt_start_position,
5464                    &mut diff_transforms_cursor,
5465                );
5466                summaries.extend(excerpt_anchors.map(|_| position));
5467            }
5468        }
5469
5470        summaries
5471    }
5472
5473    pub fn dimensions_from_points<'a, MBD>(
5474        &'a self,
5475        points: impl 'a + IntoIterator<Item = Point>,
5476    ) -> impl 'a + Iterator<Item = MBD>
5477    where
5478        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5479    {
5480        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5481        cursor.seek(&DimensionPair {
5482            key: Point::default(),
5483            value: None,
5484        });
5485        let mut points = points.into_iter();
5486        iter::from_fn(move || {
5487            let point = points.next()?;
5488
5489            cursor.seek_forward(&DimensionPair {
5490                key: point,
5491                value: None,
5492            });
5493
5494            if let Some(region) = cursor.region() {
5495                let overshoot = point - region.range.start.key;
5496                let buffer_point = region.buffer_range.start + overshoot;
5497                let mut position = region.range.start.value.unwrap();
5498                position.add_text_dim(
5499                    &region
5500                        .buffer
5501                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5502                );
5503                if point == region.range.end.key && region.has_trailing_newline {
5504                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5505                }
5506                Some(position)
5507            } else {
5508                Some(MBD::from_summary(&self.text_summary()))
5509            }
5510        })
5511    }
5512
5513    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5514    where
5515        I: 'a + IntoIterator<Item = &'a Anchor>,
5516    {
5517        let mut anchors = anchors.into_iter().enumerate().peekable();
5518        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5519        cursor.next();
5520
5521        let mut result = Vec::new();
5522
5523        while let Some((_, anchor)) = anchors.peek() {
5524            let old_excerpt_id = anchor.excerpt_id;
5525
5526            // Find the location where this anchor's excerpt should be.
5527            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5528            cursor.seek_forward(&Some(old_locator), Bias::Left);
5529
5530            let next_excerpt = cursor.item();
5531            let prev_excerpt = cursor.prev_item();
5532
5533            // Process all of the anchors for this excerpt.
5534            while let Some((anchor_ix, &anchor)) =
5535                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5536            {
5537                let mut anchor = anchor;
5538
5539                // Leave min and max anchors unchanged if invalid or
5540                // if the old excerpt still exists at this location
5541                let mut kept_position = next_excerpt
5542                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5543                    || old_excerpt_id == ExcerptId::max()
5544                    || old_excerpt_id == ExcerptId::min();
5545
5546                // If the old excerpt no longer exists at this location, then attempt to
5547                // find an equivalent position for this anchor in an adjacent excerpt.
5548                if !kept_position {
5549                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5550                        if excerpt.contains(&anchor) {
5551                            anchor.excerpt_id = excerpt.id;
5552                            kept_position = true;
5553                            break;
5554                        }
5555                    }
5556                }
5557
5558                // If there's no adjacent excerpt that contains the anchor's position,
5559                // then report that the anchor has lost its position.
5560                if !kept_position {
5561                    anchor = if let Some(excerpt) = next_excerpt {
5562                        let mut text_anchor = excerpt
5563                            .range
5564                            .context
5565                            .start
5566                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5567                        if text_anchor
5568                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5569                            .is_gt()
5570                        {
5571                            text_anchor = excerpt.range.context.end;
5572                        }
5573                        Anchor::in_buffer(excerpt.id, text_anchor)
5574                    } else if let Some(excerpt) = prev_excerpt {
5575                        let mut text_anchor = excerpt
5576                            .range
5577                            .context
5578                            .end
5579                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5580                        if text_anchor
5581                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5582                            .is_lt()
5583                        {
5584                            text_anchor = excerpt.range.context.start;
5585                        }
5586                        Anchor::in_buffer(excerpt.id, text_anchor)
5587                    } else if anchor.text_anchor.bias == Bias::Left {
5588                        Anchor::min()
5589                    } else {
5590                        Anchor::max()
5591                    };
5592                }
5593
5594                result.push((anchor_ix, anchor, kept_position));
5595            }
5596        }
5597        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5598        result
5599    }
5600
5601    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5602        self.anchor_at(position, Bias::Left)
5603    }
5604
5605    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5606        self.anchor_at(position, Bias::Right)
5607    }
5608
5609    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5610        let offset = position.to_offset(self);
5611
5612        // Find the given position in the diff transforms. Determine the corresponding
5613        // offset in the excerpts, and whether the position is within a deleted hunk.
5614        let mut diff_transforms = self
5615            .diff_transforms
5616            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5617        diff_transforms.seek(&offset, Bias::Right);
5618
5619        if offset == diff_transforms.start().0
5620            && bias == Bias::Left
5621            && let Some(prev_item) = diff_transforms.prev_item()
5622            && let DiffTransform::DeletedHunk { .. } = prev_item
5623        {
5624            diff_transforms.prev();
5625        }
5626        let offset_in_transform = offset - diff_transforms.start().0;
5627        let mut excerpt_offset = diff_transforms.start().1;
5628        let mut diff_base_anchor = None;
5629        if let Some(DiffTransform::DeletedHunk {
5630            buffer_id,
5631            base_text_byte_range,
5632            has_trailing_newline,
5633            ..
5634        }) = diff_transforms.item()
5635        {
5636            let diff = self.diffs.get(buffer_id).expect("missing diff");
5637            if offset_in_transform > base_text_byte_range.len() {
5638                debug_assert!(*has_trailing_newline);
5639                bias = Bias::Right;
5640            } else {
5641                diff_base_anchor = Some(
5642                    diff.base_text()
5643                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5644                );
5645                bias = Bias::Left;
5646            }
5647        } else {
5648            excerpt_offset += MultiBufferOffset(offset_in_transform);
5649        };
5650
5651        let mut excerpts = self
5652            .excerpts
5653            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5654        excerpts.seek(&excerpt_offset, Bias::Right);
5655        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5656            excerpts.prev();
5657        }
5658        if let Some(excerpt) = excerpts.item() {
5659            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5660            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5661                overshoot -= 1;
5662                bias = Bias::Right;
5663            }
5664
5665            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5666            let text_anchor =
5667                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5668            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5669            match diff_base_anchor {
5670                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5671                None => anchor,
5672            }
5673        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5674        {
5675            Anchor::min()
5676        } else {
5677            Anchor::max()
5678        }
5679    }
5680
5681    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5682    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5683        let (excerpt, buffer, _) = self.as_singleton()?;
5684        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5685            Some(Anchor::in_buffer(*excerpt, text_anchor))
5686        } else {
5687            None
5688        }
5689    }
5690
5691    /// Returns an anchor for the given excerpt and text anchor,
5692    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5693    pub fn anchor_range_in_excerpt(
5694        &self,
5695        excerpt_id: ExcerptId,
5696        text_anchor: Range<text::Anchor>,
5697    ) -> Option<Range<Anchor>> {
5698        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5699
5700        Some(
5701            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5702                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5703        )
5704    }
5705
5706    /// Returns an anchor for the given excerpt and text anchor,
5707    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5708    pub fn anchor_in_excerpt(
5709        &self,
5710        excerpt_id: ExcerptId,
5711        text_anchor: text::Anchor,
5712    ) -> Option<Anchor> {
5713        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5714        Self::anchor_in_excerpt_(excerpt, text_anchor)
5715    }
5716
5717    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5718    pub fn anchors_in_excerpt(
5719        &self,
5720        excerpt_id: ExcerptId,
5721        text_anchors: impl IntoIterator<Item = text::Anchor>,
5722    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5723        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5724        Some(
5725            text_anchors
5726                .into_iter()
5727                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5728        )
5729    }
5730
5731    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5732        match text_anchor.buffer_id {
5733            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5734            Some(_) => return None,
5735            None if text_anchor.is_max() || text_anchor.is_min() => {
5736                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5737            }
5738            None => return None,
5739        }
5740
5741        let context = &excerpt.range.context;
5742        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5743            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5744        {
5745            return None;
5746        }
5747
5748        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5749    }
5750
5751    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5752        Some(self.excerpt(excerpt_id)?.range.context.clone())
5753    }
5754
5755    pub fn excerpt_range_for_excerpt(
5756        &self,
5757        excerpt_id: ExcerptId,
5758    ) -> Option<ExcerptRange<text::Anchor>> {
5759        Some(self.excerpt(excerpt_id)?.range.clone())
5760    }
5761
5762    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5763        if anchor.is_min() || anchor.is_max() {
5764            // todo(lw): should be `!self.is_empty()`
5765            true
5766        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5767            excerpt.buffer.can_resolve(&anchor.text_anchor)
5768        } else {
5769            false
5770        }
5771    }
5772
5773    pub fn excerpts(
5774        &self,
5775    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5776        self.excerpts
5777            .iter()
5778            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5779    }
5780
5781    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5782    where
5783        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5784        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5785    {
5786        let excerpts = self.excerpts.cursor(());
5787        let diff_transforms = self.diff_transforms.cursor(());
5788        MultiBufferCursor {
5789            excerpts,
5790            diff_transforms,
5791            diffs: &self.diffs,
5792            cached_region: OnceCell::new(),
5793        }
5794    }
5795
5796    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5797        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5798        let mut excerpts = self
5799            .excerpts
5800            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5801        excerpts.seek(&Some(start_locator), Bias::Left);
5802        excerpts.prev();
5803
5804        let mut diff_transforms = self
5805            .diff_transforms
5806            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5807        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5808        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5809            diff_transforms.next();
5810        }
5811
5812        let excerpt = excerpts.item()?;
5813        Some(MultiBufferExcerpt {
5814            excerpt,
5815            offset: diff_transforms.start().output_dimension.0,
5816            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5817            excerpt_offset: excerpts.start().1,
5818            diff_transforms,
5819        })
5820    }
5821
5822    pub fn excerpt_boundaries_in_range<R, T>(
5823        &self,
5824        range: R,
5825    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5826    where
5827        R: RangeBounds<T>,
5828        T: ToOffset,
5829    {
5830        let start_offset;
5831        let start = match range.start_bound() {
5832            Bound::Included(start) => {
5833                start_offset = start.to_offset(self);
5834                Bound::Included(start_offset)
5835            }
5836            Bound::Excluded(_) => {
5837                panic!("not supported")
5838            }
5839            Bound::Unbounded => {
5840                start_offset = MultiBufferOffset::ZERO;
5841                Bound::Unbounded
5842            }
5843        };
5844        let end = match range.end_bound() {
5845            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5846            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5847            Bound::Unbounded => Bound::Unbounded,
5848        };
5849        let bounds = (start, end);
5850        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5851        cursor.seek(&DimensionPair {
5852            key: start_offset,
5853            value: None,
5854        });
5855
5856        if cursor
5857            .fetch_excerpt_with_range()
5858            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5859        {
5860            cursor.prev_excerpt();
5861        } else {
5862            cursor.seek_to_start_of_current_excerpt();
5863        }
5864        let mut prev_region = cursor
5865            .fetch_excerpt_with_range()
5866            .map(|(excerpt, _)| excerpt);
5867
5868        cursor.next_excerpt_forwards();
5869
5870        iter::from_fn(move || {
5871            loop {
5872                if self.singleton {
5873                    return None;
5874                }
5875
5876                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5877                cursor.next_excerpt_forwards();
5878                if !bounds.contains(&next_range.start.key) {
5879                    prev_region = Some(next_excerpt);
5880                    continue;
5881                }
5882
5883                let next_region_start = next_range.start.value.unwrap();
5884                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5885                    range.start.value.unwrap()
5886                } else {
5887                    self.max_point()
5888                };
5889
5890                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5891                    id: region.id,
5892                    buffer: region.buffer.clone(),
5893                    buffer_id: region.buffer_id,
5894                    range: region.range.clone(),
5895                    end_row: MultiBufferRow(next_region_start.row),
5896                });
5897
5898                let next = ExcerptInfo {
5899                    id: next_excerpt.id,
5900                    buffer: next_excerpt.buffer.clone(),
5901                    buffer_id: next_excerpt.buffer_id,
5902                    range: next_excerpt.range.clone(),
5903                    end_row: if next_excerpt.has_trailing_newline {
5904                        MultiBufferRow(next_region_end.row - 1)
5905                    } else {
5906                        MultiBufferRow(next_region_end.row)
5907                    },
5908                };
5909
5910                let row = MultiBufferRow(next_region_start.row);
5911
5912                prev_region = Some(next_excerpt);
5913
5914                return Some(ExcerptBoundary { row, prev, next });
5915            }
5916        })
5917    }
5918
5919    pub fn edit_count(&self) -> usize {
5920        self.edit_count
5921    }
5922
5923    pub fn non_text_state_update_count(&self) -> usize {
5924        self.non_text_state_update_count
5925    }
5926
5927    /// Returns the smallest enclosing bracket ranges containing the given range or
5928    /// None if no brackets contain range or the range is not contained in a single
5929    /// excerpt
5930    ///
5931    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5932    #[ztracing::instrument(skip_all)]
5933    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5934        &self,
5935        range: Range<T>,
5936        range_filter: Option<
5937            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5938        >,
5939    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5940        let range = range.start.to_offset(self)..range.end.to_offset(self);
5941        let mut excerpt = self.excerpt_containing(range.clone())?;
5942        let buffer = excerpt.buffer();
5943        let excerpt_buffer_range = excerpt.buffer_range();
5944
5945        // Filter to ranges contained in the excerpt
5946        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5947            excerpt_buffer_range.contains(&BufferOffset(open.start))
5948                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5949                && range_filter.is_none_or(|filter| {
5950                    filter(
5951                        buffer,
5952                        BufferOffset(open.start)..BufferOffset(close.end),
5953                        BufferOffset(close.start)..BufferOffset(close.end),
5954                    )
5955                })
5956        };
5957
5958        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5959            excerpt.map_range_to_buffer(range),
5960            Some(&range_filter),
5961        )?;
5962
5963        Some((
5964            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5965            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5966        ))
5967    }
5968
5969    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5970    /// not contained in a single excerpt
5971    pub fn enclosing_bracket_ranges<T: ToOffset>(
5972        &self,
5973        range: Range<T>,
5974    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5975    {
5976        let range = range.start.to_offset(self)..range.end.to_offset(self);
5977        let mut excerpt = self.excerpt_containing(range.clone())?;
5978
5979        Some(
5980            excerpt
5981                .buffer()
5982                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5983                .filter_map(move |pair| {
5984                    let open_range =
5985                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5986                    let close_range =
5987                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5988                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5989                        Some((
5990                            excerpt.map_range_from_buffer(open_range),
5991                            excerpt.map_range_from_buffer(close_range),
5992                        ))
5993                    } else {
5994                        None
5995                    }
5996                }),
5997        )
5998    }
5999
6000    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6001    /// not contained in a single excerpt
6002    pub fn text_object_ranges<T: ToOffset>(
6003        &self,
6004        range: Range<T>,
6005        options: TreeSitterOptions,
6006    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6007        let range = range.start.to_offset(self)..range.end.to_offset(self);
6008        self.excerpt_containing(range.clone())
6009            .map(|mut excerpt| {
6010                excerpt
6011                    .buffer()
6012                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6013                    .filter_map(move |(range, text_object)| {
6014                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6015                        if excerpt.contains_buffer_range(range.clone()) {
6016                            Some((excerpt.map_range_from_buffer(range), text_object))
6017                        } else {
6018                            None
6019                        }
6020                    })
6021            })
6022            .into_iter()
6023            .flatten()
6024    }
6025
6026    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6027    /// not contained in a single excerpt
6028    pub fn bracket_ranges<T: ToOffset>(
6029        &self,
6030        range: Range<T>,
6031    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6032    {
6033        let range = range.start.to_offset(self)..range.end.to_offset(self);
6034        let mut excerpt = self.excerpt_containing(range.clone())?;
6035        Some(
6036            excerpt
6037                .buffer()
6038                .bracket_ranges(excerpt.map_range_to_buffer(range))
6039                .filter_map(move |pair| {
6040                    let open_range =
6041                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6042                    let close_range =
6043                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6044                    excerpt
6045                        .contains_buffer_range(open_range.start..close_range.end)
6046                        .then(|| BracketMatch {
6047                            open_range: excerpt.map_range_from_buffer(open_range),
6048                            close_range: excerpt.map_range_from_buffer(close_range),
6049                            color_index: pair.color_index,
6050                            newline_only: pair.newline_only,
6051                            syntax_layer_depth: pair.syntax_layer_depth,
6052                        })
6053                })
6054                .map(BracketMatch::bracket_ranges),
6055        )
6056    }
6057
6058    pub fn redacted_ranges<'a, T: ToOffset>(
6059        &'a self,
6060        range: Range<T>,
6061        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6062    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6063        let range = range.start.to_offset(self)..range.end.to_offset(self);
6064        self.lift_buffer_metadata(range, move |buffer, range| {
6065            if redaction_enabled(buffer.file()) {
6066                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6067            } else {
6068                None
6069            }
6070        })
6071        .map(|(range, _, _)| range)
6072    }
6073
6074    pub fn runnable_ranges(
6075        &self,
6076        range: Range<Anchor>,
6077    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6078        let range = range.start.to_offset(self)..range.end.to_offset(self);
6079        self.lift_buffer_metadata(range, move |buffer, range| {
6080            Some(
6081                buffer
6082                    .runnable_ranges(range.clone())
6083                    .filter(move |runnable| {
6084                        runnable.run_range.start >= range.start
6085                            && runnable.run_range.end < range.end
6086                    })
6087                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6088            )
6089        })
6090        .map(|(run_range, runnable, _)| (run_range, runnable))
6091    }
6092
6093    pub fn line_indents(
6094        &self,
6095        start_row: MultiBufferRow,
6096        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6097    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6098        let max_point = self.max_point();
6099        let mut cursor = self.cursor::<Point, Point>();
6100        cursor.seek(&Point::new(start_row.0, 0));
6101        iter::from_fn(move || {
6102            let mut region = cursor.region()?;
6103            while !buffer_filter(&region.excerpt.buffer) {
6104                cursor.next();
6105                region = cursor.region()?;
6106            }
6107            let region = cursor.region()?;
6108            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6109            let buffer_start_row =
6110                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6111
6112            let buffer_end_row = if region.is_main_buffer
6113                && (region.has_trailing_newline || region.range.end == max_point)
6114            {
6115                region.buffer_range.end.row
6116            } else {
6117                region.buffer_range.end.row.saturating_sub(1)
6118            };
6119
6120            let line_indents = region
6121                .buffer
6122                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6123            let region_buffer_row = region.buffer_range.start.row;
6124            let region_row = region.range.start.row;
6125            let region_buffer = &region.excerpt.buffer;
6126            cursor.next();
6127            Some(line_indents.map(move |(buffer_row, indent)| {
6128                let row = region_row + (buffer_row - region_buffer_row);
6129                (MultiBufferRow(row), indent, region_buffer.as_ref())
6130            }))
6131        })
6132        .flatten()
6133    }
6134
6135    pub fn reversed_line_indents(
6136        &self,
6137        end_row: MultiBufferRow,
6138        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6139    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6140        let max_point = self.max_point();
6141        let mut cursor = self.cursor::<Point, Point>();
6142        cursor.seek(&Point::new(end_row.0, 0));
6143        iter::from_fn(move || {
6144            let mut region = cursor.region()?;
6145            while !buffer_filter(&region.excerpt.buffer) {
6146                cursor.prev();
6147                region = cursor.region()?;
6148            }
6149            let region = cursor.region()?;
6150
6151            let buffer_start_row = region.buffer_range.start.row;
6152            let buffer_end_row = if region.is_main_buffer
6153                && (region.has_trailing_newline || region.range.end == max_point)
6154            {
6155                region.buffer_range.end.row + 1
6156            } else {
6157                region.buffer_range.end.row
6158            };
6159
6160            let overshoot = end_row.0 - region.range.start.row;
6161            let buffer_end_row =
6162                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6163
6164            let line_indents = region
6165                .buffer
6166                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6167            let region_buffer_row = region.buffer_range.start.row;
6168            let region_row = region.range.start.row;
6169            let region_buffer = &region.excerpt.buffer;
6170            cursor.prev();
6171            Some(line_indents.map(move |(buffer_row, indent)| {
6172                let row = region_row + (buffer_row - region_buffer_row);
6173                (MultiBufferRow(row), indent, region_buffer.as_ref())
6174            }))
6175        })
6176        .flatten()
6177    }
6178
6179    pub async fn enclosing_indent(
6180        &self,
6181        mut target_row: MultiBufferRow,
6182    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6183        let max_row = MultiBufferRow(self.max_point().row);
6184        if target_row >= max_row {
6185            return None;
6186        }
6187
6188        let mut target_indent = self.line_indent_for_row(target_row);
6189
6190        // If the current row is at the start of an indented block, we want to return this
6191        // block as the enclosing indent.
6192        if !target_indent.is_line_empty() && target_row < max_row {
6193            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6194            if !next_line_indent.is_line_empty()
6195                && target_indent.raw_len() < next_line_indent.raw_len()
6196            {
6197                target_indent = next_line_indent;
6198                target_row.0 += 1;
6199            }
6200        }
6201
6202        const SEARCH_ROW_LIMIT: u32 = 25000;
6203        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6204        const YIELD_INTERVAL: u32 = 100;
6205
6206        let mut accessed_row_counter = 0;
6207
6208        // If there is a blank line at the current row, search for the next non indented lines
6209        if target_indent.is_line_empty() {
6210            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6211            let end =
6212                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6213
6214            let mut non_empty_line_above = None;
6215            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6216                if row < start {
6217                    break;
6218                }
6219                accessed_row_counter += 1;
6220                if accessed_row_counter == YIELD_INTERVAL {
6221                    accessed_row_counter = 0;
6222                    yield_now().await;
6223                }
6224                if !indent.is_line_empty() {
6225                    non_empty_line_above = Some((row, indent));
6226                    break;
6227                }
6228            }
6229
6230            let mut non_empty_line_below = None;
6231            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6232                if row > end {
6233                    break;
6234                }
6235                accessed_row_counter += 1;
6236                if accessed_row_counter == YIELD_INTERVAL {
6237                    accessed_row_counter = 0;
6238                    yield_now().await;
6239                }
6240                if !indent.is_line_empty() {
6241                    non_empty_line_below = Some((row, indent));
6242                    break;
6243                }
6244            }
6245
6246            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6247                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6248                    if above_indent.raw_len() >= below_indent.raw_len() {
6249                        (above_row, above_indent)
6250                    } else {
6251                        (below_row, below_indent)
6252                    }
6253                }
6254                (Some(above), None) => above,
6255                (None, Some(below)) => below,
6256                _ => return None,
6257            };
6258
6259            target_indent = indent;
6260            target_row = row;
6261        }
6262
6263        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6264        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6265
6266        let mut start_indent = None;
6267        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6268            if row < start {
6269                break;
6270            }
6271            accessed_row_counter += 1;
6272            if accessed_row_counter == YIELD_INTERVAL {
6273                accessed_row_counter = 0;
6274                yield_now().await;
6275            }
6276            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6277                start_indent = Some((row, indent));
6278                break;
6279            }
6280        }
6281        let (start_row, start_indent_size) = start_indent?;
6282
6283        let mut end_indent = (end, None);
6284        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6285            if row > end {
6286                break;
6287            }
6288            accessed_row_counter += 1;
6289            if accessed_row_counter == YIELD_INTERVAL {
6290                accessed_row_counter = 0;
6291                yield_now().await;
6292            }
6293            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6294                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6295                break;
6296            }
6297        }
6298        let (end_row, end_indent_size) = end_indent;
6299
6300        let indent = if let Some(end_indent_size) = end_indent_size {
6301            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6302                start_indent_size
6303            } else {
6304                end_indent_size
6305            }
6306        } else {
6307            start_indent_size
6308        };
6309
6310        Some((start_row..end_row, indent))
6311    }
6312
6313    pub fn indent_guides_in_range<T: ToPoint>(
6314        &self,
6315        range: Range<T>,
6316        ignore_disabled_for_language: bool,
6317        cx: &App,
6318    ) -> impl Iterator<Item = IndentGuide> {
6319        let range = range.start.to_point(self)..range.end.to_point(self);
6320        let start_row = MultiBufferRow(range.start.row);
6321        let end_row = MultiBufferRow(range.end.row);
6322
6323        let mut row_indents = self.line_indents(start_row, |buffer| {
6324            let settings =
6325                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6326            settings.indent_guides.enabled || ignore_disabled_for_language
6327        });
6328
6329        let mut result = Vec::new();
6330        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6331
6332        let mut prev_settings = None;
6333        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6334            if first_row > end_row {
6335                break;
6336            }
6337            let current_depth = indent_stack.len() as u32;
6338
6339            // Avoid retrieving the language settings repeatedly for every buffer row.
6340            if let Some((prev_buffer_id, _)) = &prev_settings
6341                && prev_buffer_id != &buffer.remote_id()
6342            {
6343                prev_settings.take();
6344            }
6345            let settings = &prev_settings
6346                .get_or_insert_with(|| {
6347                    (
6348                        buffer.remote_id(),
6349                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6350                    )
6351                })
6352                .1;
6353            let tab_size = settings.tab_size.get();
6354
6355            // When encountering empty, continue until found useful line indent
6356            // then add to the indent stack with the depth found
6357            let mut found_indent = false;
6358            let mut last_row = first_row;
6359            if line_indent.is_line_blank() {
6360                while !found_indent {
6361                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6362                        break;
6363                    };
6364                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6365                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6366                        break;
6367                    }
6368
6369                    if new_line_indent.is_line_blank() {
6370                        continue;
6371                    }
6372                    last_row = target_row.min(end_row);
6373                    line_indent = new_line_indent;
6374                    found_indent = true;
6375                    break;
6376                }
6377            } else {
6378                found_indent = true
6379            }
6380
6381            let depth = if found_indent {
6382                line_indent.len(tab_size) / tab_size
6383            } else {
6384                0
6385            };
6386
6387            match depth.cmp(&current_depth) {
6388                cmp::Ordering::Less => {
6389                    for _ in 0..(current_depth - depth) {
6390                        let mut indent = indent_stack.pop().unwrap();
6391                        if last_row != first_row {
6392                            // In this case, we landed on an empty row, had to seek forward,
6393                            // and discovered that the indent we where on is ending.
6394                            // This means that the last display row must
6395                            // be on line that ends this indent range, so we
6396                            // should display the range up to the first non-empty line
6397                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6398                        }
6399
6400                        result.push(indent)
6401                    }
6402                }
6403                cmp::Ordering::Greater => {
6404                    for next_depth in current_depth..depth {
6405                        indent_stack.push(IndentGuide {
6406                            buffer_id: buffer.remote_id(),
6407                            start_row: first_row,
6408                            end_row: last_row,
6409                            depth: next_depth,
6410                            tab_size,
6411                            settings: settings.indent_guides.clone(),
6412                        });
6413                    }
6414                }
6415                _ => {}
6416            }
6417
6418            for indent in indent_stack.iter_mut() {
6419                indent.end_row = last_row;
6420            }
6421        }
6422
6423        result.extend(indent_stack);
6424        result.into_iter()
6425    }
6426
6427    pub fn trailing_excerpt_update_count(&self) -> usize {
6428        self.trailing_excerpt_update_count
6429    }
6430
6431    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6432        self.point_to_buffer_offset(point)
6433            .and_then(|(buffer, _)| buffer.file())
6434    }
6435
6436    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6437        self.point_to_buffer_offset(offset)
6438            .and_then(|(buffer, offset)| buffer.language_at(offset))
6439    }
6440
6441    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6442        self.excerpts
6443            .first()
6444            .map(|excerpt| &excerpt.buffer)
6445            .map(|buffer| {
6446                language_settings(
6447                    buffer.language().map(|language| language.name()),
6448                    buffer.file(),
6449                    cx,
6450                )
6451            })
6452            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6453    }
6454
6455    pub fn language_settings_at<'a, T: ToOffset>(
6456        &'a self,
6457        point: T,
6458        cx: &'a App,
6459    ) -> Cow<'a, LanguageSettings> {
6460        let mut language = None;
6461        let mut file = None;
6462        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6463            language = buffer.language_at(offset);
6464            file = buffer.file();
6465        }
6466        language_settings(language.map(|l| l.name()), file, cx)
6467    }
6468
6469    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6470        self.point_to_buffer_offset(point)
6471            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6472    }
6473
6474    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6475        self.point_to_buffer_offset(point)
6476            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6477            .unwrap_or_default()
6478    }
6479
6480    pub fn language_indent_size_at<T: ToOffset>(
6481        &self,
6482        position: T,
6483        cx: &App,
6484    ) -> Option<IndentSize> {
6485        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6486        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6487    }
6488
6489    pub fn is_dirty(&self) -> bool {
6490        self.is_dirty
6491    }
6492
6493    pub fn has_deleted_file(&self) -> bool {
6494        self.has_deleted_file
6495    }
6496
6497    pub fn has_conflict(&self) -> bool {
6498        self.has_conflict
6499    }
6500
6501    pub fn has_diagnostics(&self) -> bool {
6502        self.excerpts
6503            .iter()
6504            .any(|excerpt| excerpt.buffer.has_diagnostics())
6505    }
6506
6507    pub fn diagnostic_group(
6508        &self,
6509        buffer_id: BufferId,
6510        group_id: usize,
6511    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6512        self.lift_buffer_metadata::<Point, _, _>(
6513            Point::zero()..self.max_point(),
6514            move |buffer, range| {
6515                if buffer.remote_id() != buffer_id {
6516                    return None;
6517                };
6518                Some(
6519                    buffer
6520                        .diagnostics_in_range(range, false)
6521                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6522                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6523                )
6524            },
6525        )
6526        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6527    }
6528
6529    pub fn diagnostics_in_range<'a, MBD>(
6530        &'a self,
6531        range: Range<MBD>,
6532    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6533    where
6534        MBD::TextDimension: 'a
6535            + text::ToOffset
6536            + text::FromAnchor
6537            + Sub<Output = MBD::TextDimension>
6538            + fmt::Debug
6539            + ops::Add<Output = MBD::TextDimension>
6540            + ops::AddAssign
6541            + Ord,
6542        MBD: MultiBufferDimension
6543            + Ord
6544            + Sub<Output = MBD::TextDimension>
6545            + ops::Add<MBD::TextDimension, Output = MBD>
6546            + ops::AddAssign<MBD::TextDimension>
6547            + 'a,
6548    {
6549        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6550            Some(
6551                buffer
6552                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6553                    .map(|entry| (entry.range, entry.diagnostic)),
6554            )
6555        })
6556        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6557    }
6558
6559    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6560        &'a self,
6561        range: Range<MBD>,
6562    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6563    where
6564        MBD: MultiBufferDimension
6565            + Ord
6566            + Sub<Output = MBD::TextDimension>
6567            + ops::Add<MBD::TextDimension, Output = MBD>
6568            + ops::AddAssign<MBD::TextDimension>,
6569        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6570            + ops::Add<Output = MBD::TextDimension>
6571            + text::ToOffset
6572            + text::FromAnchor
6573            + AddAssign<MBD::TextDimension>
6574            + Ord,
6575    {
6576        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6577            Some(
6578                buffer
6579                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6580                    .map(|entry| (entry.range, entry.diagnostic)),
6581            )
6582        })
6583        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6584    }
6585
6586    pub fn syntax_ancestor<T: ToOffset>(
6587        &self,
6588        range: Range<T>,
6589    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6590        let range = range.start.to_offset(self)..range.end.to_offset(self);
6591        let mut excerpt = self.excerpt_containing(range.clone())?;
6592        let node = excerpt
6593            .buffer()
6594            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6595        let node_range = node.byte_range();
6596        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6597        if !excerpt.contains_buffer_range(node_range.clone()) {
6598            return None;
6599        };
6600        Some((node, excerpt.map_range_from_buffer(node_range)))
6601    }
6602
6603    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6604        let (excerpt_id, _, buffer) = self.as_singleton()?;
6605        let outline = buffer.outline(theme);
6606        Some(Outline::new(
6607            outline
6608                .items
6609                .into_iter()
6610                .flat_map(|item| {
6611                    Some(OutlineItem {
6612                        depth: item.depth,
6613                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6614                        source_range_for_text: self
6615                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6616                        text: item.text,
6617                        highlight_ranges: item.highlight_ranges,
6618                        name_ranges: item.name_ranges,
6619                        body_range: item.body_range.and_then(|body_range| {
6620                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6621                        }),
6622                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6623                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6624                        }),
6625                    })
6626                })
6627                .collect(),
6628        ))
6629    }
6630
6631    pub fn symbols_containing<T: ToOffset>(
6632        &self,
6633        offset: T,
6634        theme: Option<&SyntaxTheme>,
6635    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6636        let anchor = self.anchor_before(offset);
6637        let excerpt @ &Excerpt {
6638            id: excerpt_id,
6639            buffer_id,
6640            ref buffer,
6641            ..
6642        } = self.excerpt(anchor.excerpt_id)?;
6643        if cfg!(debug_assertions) {
6644            match anchor.text_anchor.buffer_id {
6645                // we clearly are hitting this according to sentry, but in what situations can this occur?
6646                Some(anchor_buffer_id) => {
6647                    assert_eq!(
6648                        anchor_buffer_id, buffer_id,
6649                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6650                    )
6651                }
6652                None => assert!(anchor.is_max()),
6653            }
6654        };
6655        Some((
6656            buffer_id,
6657            buffer
6658                .symbols_containing(anchor.text_anchor, theme)
6659                .into_iter()
6660                .flat_map(|item| {
6661                    Some(OutlineItem {
6662                        depth: item.depth,
6663                        source_range_for_text: Anchor::range_in_buffer(
6664                            excerpt_id,
6665                            item.source_range_for_text,
6666                        ),
6667                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6668                        text: item.text,
6669                        highlight_ranges: item.highlight_ranges,
6670                        name_ranges: item.name_ranges,
6671                        body_range: item
6672                            .body_range
6673                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6674                        annotation_range: item
6675                            .annotation_range
6676                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6677                    })
6678                })
6679                .collect(),
6680        ))
6681    }
6682
6683    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6684        if id == ExcerptId::min() {
6685            Locator::min_ref()
6686        } else if id == ExcerptId::max() {
6687            Locator::max_ref()
6688        } else {
6689            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6690            if let Some(entry) = item
6691                && entry.id == id
6692            {
6693                return &entry.locator;
6694            }
6695            panic!("invalid excerpt id {id:?}")
6696        }
6697    }
6698
6699    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6700    fn excerpt_locators_for_ids(
6701        &self,
6702        ids: impl IntoIterator<Item = ExcerptId>,
6703    ) -> SmallVec<[Locator; 1]> {
6704        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6705        sorted_ids.sort_unstable();
6706        sorted_ids.dedup();
6707        let mut locators = SmallVec::new();
6708
6709        while sorted_ids.last() == Some(&ExcerptId::max()) {
6710            sorted_ids.pop();
6711            locators.push(Locator::max());
6712        }
6713
6714        let mut sorted_ids = sorted_ids.into_iter().peekable();
6715        locators.extend(
6716            sorted_ids
6717                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6718                .map(|_| Locator::min()),
6719        );
6720
6721        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6722        for id in sorted_ids {
6723            if cursor.seek_forward(&id, Bias::Left) {
6724                locators.push(cursor.item().unwrap().locator.clone());
6725            } else {
6726                panic!("invalid excerpt id {:?}", id);
6727            }
6728        }
6729
6730        locators.sort_unstable();
6731        locators
6732    }
6733
6734    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6735        Some(self.excerpt(excerpt_id)?.buffer_id)
6736    }
6737
6738    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6739        Some(&self.excerpt(excerpt_id)?.buffer)
6740    }
6741
6742    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6743        let mut cursor = self
6744            .excerpts
6745            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6746        let locator = self.excerpt_locator_for_id(excerpt_id);
6747        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6748        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6749            sought_exact = true;
6750            cursor.prev();
6751        } else if excerpt_id == ExcerptId::min() {
6752            sought_exact = true;
6753        }
6754        if sought_exact {
6755            let start = cursor.start().1;
6756            let end = cursor.end().1;
6757            let mut diff_transforms = self
6758                .diff_transforms
6759                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6760            diff_transforms.seek(&start, Bias::Left);
6761            let overshoot = start - diff_transforms.start().0;
6762            let start = diff_transforms.start().1 + overshoot;
6763            diff_transforms.seek(&end, Bias::Right);
6764            let overshoot = end - diff_transforms.start().0;
6765            let end = diff_transforms.start().1 + overshoot;
6766            Some(start.0..end.0)
6767        } else {
6768            None
6769        }
6770    }
6771
6772    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6773    /// to have the latest excerpt id for the one passed in and will also remap
6774    /// `ExcerptId::max()` to the corresponding excertp ID.
6775    ///
6776    /// Callers of this function should generally use the resulting excerpt's `id` field
6777    /// afterwards.
6778    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6779        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6780        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6781        let locator = self.excerpt_locator_for_id(excerpt_id);
6782        cursor.seek(&Some(locator), Bias::Left);
6783        if let Some(excerpt) = cursor.item()
6784            && excerpt.id == excerpt_id
6785        {
6786            return Some(excerpt);
6787        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6788            cursor.prev();
6789            return cursor.item();
6790        }
6791        None
6792    }
6793
6794    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6795    pub fn excerpt_containing<T: ToOffset>(
6796        &self,
6797        range: Range<T>,
6798    ) -> Option<MultiBufferExcerpt<'_>> {
6799        let range = range.start.to_offset(self)..range.end.to_offset(self);
6800        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6801        cursor.seek(&range.start);
6802
6803        let start_excerpt = cursor.excerpt()?;
6804        if range.end != range.start {
6805            cursor.seek_forward(&range.end);
6806            if cursor.excerpt()?.id != start_excerpt.id {
6807                return None;
6808            }
6809        }
6810
6811        cursor.seek_to_start_of_current_excerpt();
6812        let region = cursor.region()?;
6813        let offset = region.range.start;
6814        let buffer_offset = start_excerpt.buffer_start_offset();
6815        let excerpt_offset = *cursor.excerpts.start();
6816        Some(MultiBufferExcerpt {
6817            diff_transforms: cursor.diff_transforms,
6818            excerpt: start_excerpt,
6819            offset,
6820            buffer_offset,
6821            excerpt_offset,
6822        })
6823    }
6824
6825    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6826        if let Some(id) = anchor.text_anchor.buffer_id {
6827            return Some(id);
6828        }
6829        let excerpt = self.excerpt_containing(anchor..anchor)?;
6830        Some(excerpt.buffer_id())
6831    }
6832
6833    pub fn selections_in_range<'a>(
6834        &'a self,
6835        range: &'a Range<Anchor>,
6836        include_local: bool,
6837    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6838        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6839        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6840        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6841        cursor.seek(start_locator, Bias::Left);
6842        cursor
6843            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6844            .flat_map(move |excerpt| {
6845                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6846                if excerpt.id == range.start.excerpt_id {
6847                    query_range.start = range.start.text_anchor;
6848                }
6849                if excerpt.id == range.end.excerpt_id {
6850                    query_range.end = range.end.text_anchor;
6851                }
6852
6853                excerpt
6854                    .buffer
6855                    .selections_in_range(query_range, include_local)
6856                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6857                        selections.map(move |selection| {
6858                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6859                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6860                            if range.start.cmp(&start, self).is_gt() {
6861                                start = range.start;
6862                            }
6863                            if range.end.cmp(&end, self).is_lt() {
6864                                end = range.end;
6865                            }
6866
6867                            (
6868                                replica_id,
6869                                line_mode,
6870                                cursor_shape,
6871                                Selection {
6872                                    id: selection.id,
6873                                    start,
6874                                    end,
6875                                    reversed: selection.reversed,
6876                                    goal: selection.goal,
6877                                },
6878                            )
6879                        })
6880                    })
6881            })
6882    }
6883
6884    pub fn show_headers(&self) -> bool {
6885        self.show_headers
6886    }
6887
6888    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6889        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6890    }
6891
6892    pub fn all_diff_hunks_expanded(&self) -> bool {
6893        self.all_diff_hunks_expanded
6894    }
6895
6896    /// Visually annotates a position or range with the `Debug` representation of a value. The
6897    /// callsite of this function is used as a key - previous annotations will be removed.
6898    #[cfg(debug_assertions)]
6899    #[track_caller]
6900    pub fn debug<V, R>(&self, ranges: &R, value: V)
6901    where
6902        R: debug::ToMultiBufferDebugRanges,
6903        V: std::fmt::Debug,
6904    {
6905        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6906    }
6907
6908    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6909    /// debug annotations with the same key will be removed. The key is also used to determine the
6910    /// annotation's color.
6911    #[cfg(debug_assertions)]
6912    #[track_caller]
6913    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6914    where
6915        K: std::hash::Hash + 'static,
6916        R: debug::ToMultiBufferDebugRanges,
6917        V: std::fmt::Debug,
6918    {
6919        let text_ranges = ranges
6920            .to_multi_buffer_debug_ranges(self)
6921            .into_iter()
6922            .flat_map(|range| {
6923                self.range_to_buffer_ranges(range.start..=range.end)
6924                    .into_iter()
6925                    .map(|(buffer, range, _excerpt_id)| {
6926                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6927                    })
6928            })
6929            .collect();
6930        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6931            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6932        });
6933    }
6934
6935    fn excerpt_edits_for_diff_change(
6936        &self,
6937        buffer_state: &BufferState,
6938        diff_change_range: Range<usize>,
6939    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6940        let mut excerpt_edits = Vec::new();
6941        for locator in &buffer_state.excerpts {
6942            let mut cursor = self
6943                .excerpts
6944                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6945            cursor.seek_forward(&Some(locator), Bias::Left);
6946            if let Some(excerpt) = cursor.item()
6947                && excerpt.locator == *locator
6948            {
6949                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6950                if diff_change_range.end < excerpt_buffer_range.start
6951                    || diff_change_range.start > excerpt_buffer_range.end
6952                {
6953                    continue;
6954                }
6955                let excerpt_start = cursor.start().1;
6956                let excerpt_len = excerpt.text_summary.len;
6957                let diff_change_start_in_excerpt = diff_change_range
6958                    .start
6959                    .saturating_sub(excerpt_buffer_range.start);
6960                let diff_change_end_in_excerpt = diff_change_range
6961                    .end
6962                    .saturating_sub(excerpt_buffer_range.start);
6963                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6964                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6965                excerpt_edits.push(Edit {
6966                    old: edit_start..edit_end,
6967                    new: edit_start..edit_end,
6968                });
6969            }
6970        }
6971        excerpt_edits
6972    }
6973}
6974
6975#[cfg(any(test, feature = "test-support"))]
6976impl MultiBufferSnapshot {
6977    pub fn random_byte_range(
6978        &self,
6979        start_offset: MultiBufferOffset,
6980        rng: &mut impl rand::Rng,
6981    ) -> Range<MultiBufferOffset> {
6982        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6983        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6984        start..end
6985    }
6986
6987    #[cfg(any(test, feature = "test-support"))]
6988    fn check_invariants(&self) {
6989        let excerpts = self.excerpts.items(());
6990        let excerpt_ids = self.excerpt_ids.items(());
6991
6992        for (ix, excerpt) in excerpts.iter().enumerate() {
6993            if ix == 0 {
6994                if excerpt.locator <= Locator::min() {
6995                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6996                }
6997            } else if excerpt.locator <= excerpts[ix - 1].locator {
6998                panic!("excerpts are out-of-order: {:?}", excerpts);
6999            }
7000        }
7001
7002        for (ix, entry) in excerpt_ids.iter().enumerate() {
7003            if ix == 0 {
7004                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7005                    panic!("invalid first excerpt id {:?}", entry.id);
7006                }
7007            } else if entry.id <= excerpt_ids[ix - 1].id {
7008                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7009            }
7010        }
7011
7012        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7013            panic!(
7014                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7015                self.excerpts.summary().text,
7016                self.diff_transforms.summary().input,
7017                self.diff_transforms.items(()),
7018            );
7019        }
7020
7021        let mut prev_transform: Option<&DiffTransform> = None;
7022        for item in self.diff_transforms.iter() {
7023            if let DiffTransform::BufferContent {
7024                summary,
7025                inserted_hunk_info,
7026            } = item
7027            {
7028                if let Some(DiffTransform::BufferContent {
7029                    inserted_hunk_info: prev_inserted_hunk_info,
7030                    ..
7031                }) = prev_transform
7032                    && *inserted_hunk_info == *prev_inserted_hunk_info
7033                {
7034                    panic!(
7035                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7036                        self.diff_transforms.items(())
7037                    );
7038                }
7039                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7040                    panic!("empty buffer content transform");
7041                }
7042            }
7043            prev_transform = Some(item);
7044        }
7045    }
7046}
7047
7048impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7049where
7050    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7051    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7052{
7053    #[instrument(skip_all)]
7054    fn seek(&mut self, position: &MBD) {
7055        let position = OutputDimension(*position);
7056        self.cached_region.take();
7057        self.diff_transforms.seek(&position, Bias::Right);
7058        if self.diff_transforms.item().is_none()
7059            && self.diff_transforms.start().output_dimension == position
7060        {
7061            self.diff_transforms.prev();
7062        }
7063
7064        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7065        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7066            let overshoot = position - self.diff_transforms.start().output_dimension;
7067            excerpt_position += overshoot;
7068        }
7069
7070        self.excerpts.seek(&excerpt_position, Bias::Right);
7071        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7072            self.excerpts.prev();
7073        }
7074    }
7075
7076    fn seek_forward(&mut self, position: &MBD) {
7077        let position = OutputDimension(*position);
7078        self.cached_region.take();
7079        self.diff_transforms.seek_forward(&position, Bias::Right);
7080        if self.diff_transforms.item().is_none()
7081            && self.diff_transforms.start().output_dimension == position
7082        {
7083            self.diff_transforms.prev();
7084        }
7085
7086        let overshoot = position - self.diff_transforms.start().output_dimension;
7087        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7088        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7089            excerpt_position += overshoot;
7090        }
7091
7092        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7093        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7094            self.excerpts.prev();
7095        }
7096    }
7097
7098    fn next_excerpt(&mut self) {
7099        self.excerpts.next();
7100        self.seek_to_start_of_current_excerpt();
7101    }
7102
7103    fn prev_excerpt(&mut self) {
7104        self.excerpts.prev();
7105        self.seek_to_start_of_current_excerpt();
7106    }
7107
7108    fn seek_to_start_of_current_excerpt(&mut self) {
7109        self.cached_region.take();
7110
7111        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7112            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7113            && self.diff_transforms.next_item().is_some()
7114        {
7115            self.diff_transforms.next();
7116        }
7117    }
7118
7119    fn next_excerpt_forwards(&mut self) {
7120        self.excerpts.next();
7121        self.seek_to_start_of_current_excerpt_forward();
7122    }
7123
7124    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7125        self.cached_region.take();
7126
7127        if self
7128            .diff_transforms
7129            .seek_forward(self.excerpts.start(), Bias::Left)
7130            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7131            && self.diff_transforms.next_item().is_some()
7132        {
7133            self.diff_transforms.next();
7134        }
7135    }
7136
7137    fn next(&mut self) {
7138        self.cached_region.take();
7139        match self
7140            .diff_transforms
7141            .end()
7142            .excerpt_dimension
7143            .cmp(&self.excerpts.end())
7144        {
7145            cmp::Ordering::Less => self.diff_transforms.next(),
7146            cmp::Ordering::Greater => self.excerpts.next(),
7147            cmp::Ordering::Equal => {
7148                self.diff_transforms.next();
7149                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7150                    || self.diff_transforms.item().is_none()
7151                {
7152                    self.excerpts.next();
7153                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7154                    self.diff_transforms.item()
7155                    && self
7156                        .excerpts
7157                        .item()
7158                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7159                {
7160                    self.excerpts.next();
7161                }
7162            }
7163        }
7164    }
7165
7166    fn prev(&mut self) {
7167        self.cached_region.take();
7168        match self
7169            .diff_transforms
7170            .start()
7171            .excerpt_dimension
7172            .cmp(self.excerpts.start())
7173        {
7174            cmp::Ordering::Less => self.excerpts.prev(),
7175            cmp::Ordering::Greater => self.diff_transforms.prev(),
7176            cmp::Ordering::Equal => {
7177                self.diff_transforms.prev();
7178                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7179                    || self.diff_transforms.item().is_none()
7180                {
7181                    self.excerpts.prev();
7182                }
7183            }
7184        }
7185    }
7186
7187    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7188        self.cached_region
7189            .get_or_init(|| self.build_region())
7190            .as_ref()
7191    }
7192
7193    fn is_at_start_of_excerpt(&mut self) -> bool {
7194        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7195            return false;
7196        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7197            return true;
7198        }
7199
7200        self.diff_transforms.prev();
7201        let prev_transform = self.diff_transforms.item();
7202        self.diff_transforms.next();
7203
7204        prev_transform.is_none_or(|next_transform| {
7205            matches!(next_transform, DiffTransform::BufferContent { .. })
7206        })
7207    }
7208
7209    fn is_at_end_of_excerpt(&self) -> bool {
7210        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7211            return false;
7212        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7213            || self.diff_transforms.item().is_none()
7214        {
7215            return true;
7216        }
7217
7218        let next_transform = self.diff_transforms.next_item();
7219        next_transform.is_none_or(|next_transform| match next_transform {
7220            DiffTransform::BufferContent { .. } => true,
7221            DiffTransform::DeletedHunk { hunk_info, .. } => self
7222                .excerpts
7223                .item()
7224                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7225        })
7226    }
7227
7228    fn main_buffer_position(&self) -> Option<BD> {
7229        let excerpt = self.excerpts.item()?;
7230        let buffer = &excerpt.buffer;
7231        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7232        let mut buffer_start = buffer_context_start;
7233        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7234        buffer_start += overshoot;
7235        Some(buffer_start)
7236    }
7237
7238    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7239        let excerpt = self.excerpts.item()?;
7240        match self.diff_transforms.item()? {
7241            DiffTransform::DeletedHunk {
7242                buffer_id,
7243                base_text_byte_range,
7244                has_trailing_newline,
7245                hunk_info,
7246                ..
7247            } => {
7248                let diff = self.diffs.get(buffer_id)?;
7249                let buffer = diff.base_text();
7250                let mut rope_cursor = buffer.as_rope().cursor(0);
7251                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7252                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7253                let mut buffer_end = buffer_start;
7254                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7255                let start = self.diff_transforms.start().output_dimension.0;
7256                let end = self.diff_transforms.end().output_dimension.0;
7257                Some(MultiBufferRegion {
7258                    buffer,
7259                    excerpt,
7260                    has_trailing_newline: *has_trailing_newline,
7261                    is_main_buffer: false,
7262                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7263                        hunk_info.hunk_secondary_status,
7264                    )),
7265                    buffer_range: buffer_start..buffer_end,
7266                    range: start..end,
7267                })
7268            }
7269            DiffTransform::BufferContent {
7270                inserted_hunk_info, ..
7271            } => {
7272                let buffer = &excerpt.buffer;
7273                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7274
7275                let mut start = self.diff_transforms.start().output_dimension.0;
7276                let mut buffer_start = buffer_context_start;
7277                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7278                    let overshoot =
7279                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7280                    start += overshoot;
7281                } else {
7282                    let overshoot =
7283                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7284                    buffer_start += overshoot;
7285                }
7286
7287                let mut end;
7288                let mut buffer_end;
7289                let has_trailing_newline;
7290                let transform_end = self.diff_transforms.end();
7291                if transform_end.excerpt_dimension < self.excerpts.end() {
7292                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7293                    end = transform_end.output_dimension.0;
7294                    buffer_end = buffer_context_start;
7295                    buffer_end += overshoot;
7296                    has_trailing_newline = false;
7297                } else {
7298                    let overshoot =
7299                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7300                    end = self.diff_transforms.start().output_dimension.0;
7301                    end += overshoot;
7302                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7303                    has_trailing_newline = excerpt.has_trailing_newline;
7304                };
7305
7306                let diff_hunk_status = inserted_hunk_info.map(|info| {
7307                    if info.is_logically_deleted {
7308                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7309                    } else {
7310                        DiffHunkStatus::added(info.hunk_secondary_status)
7311                    }
7312                });
7313
7314                Some(MultiBufferRegion {
7315                    buffer,
7316                    excerpt,
7317                    has_trailing_newline,
7318                    is_main_buffer: true,
7319                    diff_hunk_status,
7320                    buffer_range: buffer_start..buffer_end,
7321                    range: start..end,
7322                })
7323            }
7324        }
7325    }
7326
7327    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7328        let excerpt = self.excerpts.item()?;
7329        match self.diff_transforms.item()? {
7330            &DiffTransform::DeletedHunk { .. } => {
7331                let start = self.diff_transforms.start().output_dimension.0;
7332                let end = self.diff_transforms.end().output_dimension.0;
7333                Some((excerpt, start..end))
7334            }
7335            DiffTransform::BufferContent { .. } => {
7336                let mut start = self.diff_transforms.start().output_dimension.0;
7337                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7338                    let overshoot =
7339                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7340                    start += overshoot;
7341                }
7342
7343                let mut end;
7344                let transform_end = self.diff_transforms.end();
7345                if transform_end.excerpt_dimension < self.excerpts.end() {
7346                    end = transform_end.output_dimension.0;
7347                } else {
7348                    let overshoot =
7349                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7350                    end = self.diff_transforms.start().output_dimension.0;
7351                    end += overshoot;
7352                };
7353
7354                Some((excerpt, start..end))
7355            }
7356        }
7357    }
7358
7359    fn excerpt(&self) -> Option<&'a Excerpt> {
7360        self.excerpts.item()
7361    }
7362}
7363
7364impl Excerpt {
7365    fn new(
7366        id: ExcerptId,
7367        locator: Locator,
7368        buffer_id: BufferId,
7369        buffer: Arc<BufferSnapshot>,
7370        range: ExcerptRange<text::Anchor>,
7371        has_trailing_newline: bool,
7372    ) -> Self {
7373        Excerpt {
7374            id,
7375            locator,
7376            max_buffer_row: range.context.end.to_point(&buffer).row,
7377            text_summary: buffer
7378                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7379            buffer_id,
7380            buffer,
7381            range,
7382            has_trailing_newline,
7383        }
7384    }
7385
7386    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7387        let content_start = self.range.context.start.to_offset(&self.buffer);
7388        let chunks_start = content_start + range.start;
7389        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7390
7391        let has_footer = self.has_trailing_newline
7392            && range.start <= self.text_summary.len
7393            && range.end > self.text_summary.len;
7394
7395        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7396
7397        ExcerptChunks {
7398            excerpt_id: self.id,
7399            content_chunks,
7400            has_footer,
7401        }
7402    }
7403
7404    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7405        let content_start = self.range.context.start.to_offset(&self.buffer);
7406        let chunks_start = content_start + range.start;
7407        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7408        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7409        excerpt_chunks.has_footer = self.has_trailing_newline
7410            && range.start <= self.text_summary.len
7411            && range.end > self.text_summary.len;
7412    }
7413
7414    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7415        if text_anchor
7416            .cmp(&self.range.context.start, &self.buffer)
7417            .is_lt()
7418        {
7419            self.range.context.start
7420        } else if text_anchor
7421            .cmp(&self.range.context.end, &self.buffer)
7422            .is_gt()
7423        {
7424            self.range.context.end
7425        } else {
7426            text_anchor
7427        }
7428    }
7429
7430    fn contains(&self, anchor: &Anchor) -> bool {
7431        (anchor.text_anchor.buffer_id == None
7432            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7433            && self
7434                .range
7435                .context
7436                .start
7437                .cmp(&anchor.text_anchor, &self.buffer)
7438                .is_le()
7439            && self
7440                .range
7441                .context
7442                .end
7443                .cmp(&anchor.text_anchor, &self.buffer)
7444                .is_ge()
7445    }
7446
7447    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7448    fn buffer_start_offset(&self) -> BufferOffset {
7449        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7450    }
7451
7452    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7453    fn buffer_end_offset(&self) -> BufferOffset {
7454        self.buffer_start_offset() + self.text_summary.len
7455    }
7456}
7457
7458impl<'a> MultiBufferExcerpt<'a> {
7459    pub fn id(&self) -> ExcerptId {
7460        self.excerpt.id
7461    }
7462
7463    pub fn buffer_id(&self) -> BufferId {
7464        self.excerpt.buffer_id
7465    }
7466
7467    pub fn start_anchor(&self) -> Anchor {
7468        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7469    }
7470
7471    pub fn end_anchor(&self) -> Anchor {
7472        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7473    }
7474
7475    pub fn buffer(&self) -> &'a BufferSnapshot {
7476        &self.excerpt.buffer
7477    }
7478
7479    pub fn buffer_range(&self) -> Range<BufferOffset> {
7480        self.buffer_offset
7481            ..BufferOffset(
7482                self.excerpt
7483                    .range
7484                    .context
7485                    .end
7486                    .to_offset(&self.excerpt.buffer.text),
7487            )
7488    }
7489
7490    pub fn start_offset(&self) -> MultiBufferOffset {
7491        self.offset
7492    }
7493
7494    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7495    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7496        self.map_range_to_buffer(offset..offset).start
7497    }
7498
7499    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7500    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7501        self.diff_transforms
7502            .seek(&OutputDimension(range.start), Bias::Right);
7503        let start = self.map_offset_to_buffer_internal(range.start);
7504        let end = if range.end > range.start {
7505            self.diff_transforms
7506                .seek_forward(&OutputDimension(range.end), Bias::Right);
7507            self.map_offset_to_buffer_internal(range.end)
7508        } else {
7509            start
7510        };
7511        start..end
7512    }
7513
7514    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7515        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7516        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7517            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7518        };
7519        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7520        self.buffer_offset + offset_in_excerpt
7521    }
7522
7523    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7524    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7525        self.map_range_from_buffer(buffer_offset..buffer_offset)
7526            .start
7527    }
7528
7529    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7530    pub fn map_range_from_buffer(
7531        &mut self,
7532        buffer_range: Range<BufferOffset>,
7533    ) -> Range<MultiBufferOffset> {
7534        if buffer_range.start < self.buffer_offset {
7535            log::warn!(
7536                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7537            );
7538            return self.offset..self.offset;
7539        }
7540        let overshoot = buffer_range.start - self.buffer_offset;
7541        let excerpt_offset = self.excerpt_offset + overshoot;
7542        let excerpt_seek_dim = excerpt_offset;
7543        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7544        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7545            log::warn!(
7546                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7547            );
7548            return self.offset..self.offset;
7549        }
7550        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7551        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7552
7553        let end = if buffer_range.start < buffer_range.end {
7554            let overshoot = buffer_range.end - self.buffer_offset;
7555            let excerpt_offset = self.excerpt_offset + overshoot;
7556            let excerpt_seek_dim = excerpt_offset;
7557            self.diff_transforms
7558                .seek_forward(&excerpt_seek_dim, Bias::Right);
7559            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7560            // todo(lw): Clamp end to the excerpt boundaries
7561            self.diff_transforms.start().output_dimension.0 + overshoot
7562        } else {
7563            start
7564        };
7565
7566        start..end
7567    }
7568
7569    /// Returns true if the entirety of the given range is in the buffer's excerpt
7570    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7571        range.start >= self.excerpt.buffer_start_offset()
7572            && range.end <= self.excerpt.buffer_end_offset()
7573    }
7574
7575    /// Returns true if any part of the given range is in the buffer's excerpt
7576    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7577        range.start <= self.excerpt.buffer_end_offset()
7578            && range.end >= self.excerpt.buffer_start_offset()
7579    }
7580
7581    pub fn max_buffer_row(&self) -> u32 {
7582        self.excerpt.max_buffer_row
7583    }
7584}
7585
7586impl ExcerptId {
7587    pub fn min() -> Self {
7588        Self(0)
7589    }
7590
7591    pub fn max() -> Self {
7592        Self(u32::MAX)
7593    }
7594
7595    pub fn to_proto(self) -> u64 {
7596        self.0 as _
7597    }
7598
7599    pub fn from_proto(proto: u64) -> Self {
7600        Self(proto as _)
7601    }
7602
7603    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7604        let a = snapshot.excerpt_locator_for_id(*self);
7605        let b = snapshot.excerpt_locator_for_id(*other);
7606        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7607    }
7608}
7609
7610impl From<ExcerptId> for usize {
7611    fn from(val: ExcerptId) -> Self {
7612        val.0 as usize
7613    }
7614}
7615
7616impl fmt::Debug for Excerpt {
7617    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7618        f.debug_struct("Excerpt")
7619            .field("id", &self.id)
7620            .field("locator", &self.locator)
7621            .field("buffer_id", &self.buffer_id)
7622            .field("range", &self.range)
7623            .field("text_summary", &self.text_summary)
7624            .field("has_trailing_newline", &self.has_trailing_newline)
7625            .finish()
7626    }
7627}
7628
7629impl sum_tree::Item for Excerpt {
7630    type Summary = ExcerptSummary;
7631
7632    fn summary(&self, _cx: ()) -> Self::Summary {
7633        let mut text = self.text_summary;
7634        if self.has_trailing_newline {
7635            text += TextSummary::from("\n");
7636        }
7637        ExcerptSummary {
7638            excerpt_id: self.id,
7639            excerpt_locator: self.locator.clone(),
7640            widest_line_number: self.max_buffer_row,
7641            text: text.into(),
7642        }
7643    }
7644}
7645
7646impl sum_tree::Item for ExcerptIdMapping {
7647    type Summary = ExcerptId;
7648
7649    fn summary(&self, _cx: ()) -> Self::Summary {
7650        self.id
7651    }
7652}
7653
7654impl sum_tree::KeyedItem for ExcerptIdMapping {
7655    type Key = ExcerptId;
7656
7657    fn key(&self) -> Self::Key {
7658        self.id
7659    }
7660}
7661
7662impl DiffTransform {
7663    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7664        match self {
7665            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7666            DiffTransform::BufferContent {
7667                inserted_hunk_info, ..
7668            } => *inserted_hunk_info,
7669        }
7670    }
7671}
7672
7673impl sum_tree::Item for DiffTransform {
7674    type Summary = DiffTransformSummary;
7675
7676    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7677        match self {
7678            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7679                input: *summary,
7680                output: *summary,
7681            },
7682            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7683                input: MBTextSummary::default(),
7684                output: summary.into(),
7685            },
7686        }
7687    }
7688}
7689
7690impl DiffTransformSummary {
7691    fn excerpt_len(&self) -> ExcerptOffset {
7692        ExcerptDimension(self.input.len)
7693    }
7694}
7695
7696impl sum_tree::ContextLessSummary for DiffTransformSummary {
7697    fn zero() -> Self {
7698        DiffTransformSummary {
7699            input: MBTextSummary::default(),
7700            output: MBTextSummary::default(),
7701        }
7702    }
7703
7704    fn add_summary(&mut self, other: &Self) {
7705        self.input += other.input;
7706        self.output += other.output;
7707    }
7708}
7709
7710impl sum_tree::ContextLessSummary for ExcerptId {
7711    fn zero() -> Self {
7712        Self(0)
7713    }
7714
7715    fn add_summary(&mut self, summary: &Self) {
7716        *self = cmp::max(*self, *summary);
7717    }
7718}
7719
7720impl sum_tree::ContextLessSummary for ExcerptSummary {
7721    fn zero() -> Self {
7722        Self::default()
7723    }
7724
7725    fn add_summary(&mut self, summary: &Self) {
7726        debug_assert!(
7727            summary.excerpt_locator > self.excerpt_locator
7728                || self.excerpt_locator == Locator::min(),
7729            "Excerpt locators must be in ascending order: {:?} > {:?}",
7730            summary.excerpt_locator,
7731            self.excerpt_locator
7732        );
7733        self.excerpt_locator = summary.excerpt_locator.clone();
7734        self.text += summary.text;
7735        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7736    }
7737}
7738
7739impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7740    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7741        Ord::cmp(&Some(self), cursor_location)
7742    }
7743}
7744
7745impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7746    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7747        Ord::cmp(self, &cursor_location.excerpt_locator)
7748    }
7749}
7750
7751impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7752where
7753    MBD: MultiBufferDimension + Default,
7754{
7755    fn zero(_: ()) -> Self {
7756        ExcerptDimension(MBD::default())
7757    }
7758
7759    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7760        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7761    }
7762}
7763
7764impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7765    fn zero(_cx: ()) -> Self {
7766        Default::default()
7767    }
7768
7769    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7770        *self = Some(&summary.excerpt_locator);
7771    }
7772}
7773
7774impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7775    fn zero(_cx: ()) -> Self {
7776        Default::default()
7777    }
7778
7779    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7780        *self = Some(summary.excerpt_id);
7781    }
7782}
7783
7784#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7785struct OutputDimension<T>(T);
7786
7787impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7788    fn eq(&self, other: &T) -> bool {
7789        self.0 == *other
7790    }
7791}
7792
7793impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7794    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7795        self.0.partial_cmp(other)
7796    }
7797}
7798
7799impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7800where
7801    T: ops::Sub<U, Output = R>,
7802{
7803    type Output = R;
7804
7805    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7806        self.0 - other.0
7807    }
7808}
7809
7810impl<R, T, U> ops::Add<U> for OutputDimension<T>
7811where
7812    T: ops::Add<U, Output = R>,
7813{
7814    type Output = OutputDimension<R>;
7815
7816    fn add(self, other: U) -> Self::Output {
7817        OutputDimension(self.0 + other)
7818    }
7819}
7820
7821impl<T, U> AddAssign<U> for OutputDimension<T>
7822where
7823    T: AddAssign<U>,
7824{
7825    fn add_assign(&mut self, other: U) {
7826        self.0 += other;
7827    }
7828}
7829
7830impl<T, U> SubAssign<U> for OutputDimension<T>
7831where
7832    T: SubAssign<U>,
7833{
7834    fn sub_assign(&mut self, other: U) {
7835        self.0 -= other;
7836    }
7837}
7838
7839#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7840struct ExcerptDimension<T>(T);
7841
7842impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7843    fn eq(&self, other: &T) -> bool {
7844        self.0 == *other
7845    }
7846}
7847
7848impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7849    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7850        self.0.partial_cmp(other)
7851    }
7852}
7853
7854impl ExcerptOffset {
7855    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7856        self.0.saturating_sub(other.0)
7857    }
7858}
7859
7860impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7861where
7862    T: ops::Sub<U, Output = R>,
7863{
7864    type Output = R;
7865
7866    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7867        self.0 - other.0
7868    }
7869}
7870
7871impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7872where
7873    T: ops::Add<U, Output = R>,
7874{
7875    type Output = ExcerptDimension<R>;
7876
7877    fn add(self, other: U) -> Self::Output {
7878        ExcerptDimension(self.0 + other)
7879    }
7880}
7881
7882impl<T, U> AddAssign<U> for ExcerptDimension<T>
7883where
7884    T: AddAssign<U>,
7885{
7886    fn add_assign(&mut self, other: U) {
7887        self.0 += other;
7888    }
7889}
7890
7891impl<T, U> SubAssign<U> for ExcerptDimension<T>
7892where
7893    T: SubAssign<U>,
7894{
7895    fn sub_assign(&mut self, other: U) {
7896        self.0 -= other;
7897    }
7898}
7899
7900impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7901    fn zero(_: ()) -> Self {
7902        MultiBufferOffset::ZERO
7903    }
7904
7905    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7906        *self += summary.output.len;
7907    }
7908}
7909
7910impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7911    for ExcerptDimension<MBD>
7912where
7913    MBD: MultiBufferDimension + Ord,
7914{
7915    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7916        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7917    }
7918}
7919
7920impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7921    for ExcerptDimension<MBD>
7922where
7923    MBD: MultiBufferDimension + Ord,
7924{
7925    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7926        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7927    }
7928}
7929
7930impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7931    for ExcerptDimension<MBD>
7932{
7933    fn zero(_: ()) -> Self {
7934        ExcerptDimension(MBD::default())
7935    }
7936
7937    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7938        self.0.add_mb_text_summary(&summary.input)
7939    }
7940}
7941
7942impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7943    for OutputDimension<MBD>
7944where
7945    MBD: MultiBufferDimension + Ord,
7946{
7947    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7948        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7949    }
7950}
7951
7952impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7953    for OutputDimension<MBD>
7954{
7955    fn zero(_: ()) -> Self {
7956        OutputDimension(MBD::default())
7957    }
7958
7959    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7960        self.0.add_mb_text_summary(&summary.output)
7961    }
7962}
7963
7964impl MultiBufferRows<'_> {
7965    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7966        self.point = Point::new(row, 0);
7967        self.cursor.seek(&self.point);
7968    }
7969}
7970
7971impl Iterator for MultiBufferRows<'_> {
7972    type Item = RowInfo;
7973
7974    fn next(&mut self) -> Option<Self::Item> {
7975        if self.is_empty && self.point.row == 0 {
7976            self.point += Point::new(1, 0);
7977            return Some(RowInfo {
7978                buffer_id: None,
7979                buffer_row: Some(0),
7980                multibuffer_row: Some(MultiBufferRow(0)),
7981                diff_status: None,
7982                expand_info: None,
7983                wrapped_buffer_row: None,
7984            });
7985        }
7986
7987        let mut region = self.cursor.region()?.clone();
7988        while self.point >= region.range.end {
7989            self.cursor.next();
7990            if let Some(next_region) = self.cursor.region() {
7991                region = next_region.clone();
7992            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7993                let multibuffer_row = MultiBufferRow(self.point.row);
7994                let last_excerpt = self
7995                    .cursor
7996                    .excerpts
7997                    .item()
7998                    .or(self.cursor.excerpts.prev_item())?;
7999                let last_row = last_excerpt
8000                    .range
8001                    .context
8002                    .end
8003                    .to_point(&last_excerpt.buffer)
8004                    .row;
8005
8006                let first_row = last_excerpt
8007                    .range
8008                    .context
8009                    .start
8010                    .to_point(&last_excerpt.buffer)
8011                    .row;
8012
8013                let expand_info = if self.is_singleton {
8014                    None
8015                } else {
8016                    let needs_expand_up = first_row == last_row
8017                        && last_row > 0
8018                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8019                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8020
8021                    if needs_expand_up && needs_expand_down {
8022                        Some(ExpandExcerptDirection::UpAndDown)
8023                    } else if needs_expand_up {
8024                        Some(ExpandExcerptDirection::Up)
8025                    } else if needs_expand_down {
8026                        Some(ExpandExcerptDirection::Down)
8027                    } else {
8028                        None
8029                    }
8030                    .map(|direction| ExpandInfo {
8031                        direction,
8032                        excerpt_id: last_excerpt.id,
8033                    })
8034                };
8035                self.point += Point::new(1, 0);
8036                return Some(RowInfo {
8037                    buffer_id: Some(last_excerpt.buffer_id),
8038                    buffer_row: Some(last_row),
8039                    multibuffer_row: Some(multibuffer_row),
8040                    diff_status: None,
8041                    wrapped_buffer_row: None,
8042                    expand_info,
8043                });
8044            } else {
8045                return None;
8046            };
8047        }
8048
8049        let overshoot = self.point - region.range.start;
8050        let buffer_point = region.buffer_range.start + overshoot;
8051        let expand_info = if self.is_singleton {
8052            None
8053        } else {
8054            let needs_expand_up = self.point.row == region.range.start.row
8055                && self.cursor.is_at_start_of_excerpt()
8056                && buffer_point.row > 0;
8057            let needs_expand_down = (region.excerpt.has_trailing_newline
8058                && self.point.row + 1 == region.range.end.row
8059                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8060                && self.cursor.is_at_end_of_excerpt()
8061                && buffer_point.row < region.buffer.max_point().row;
8062
8063            if needs_expand_up && needs_expand_down {
8064                Some(ExpandExcerptDirection::UpAndDown)
8065            } else if needs_expand_up {
8066                Some(ExpandExcerptDirection::Up)
8067            } else if needs_expand_down {
8068                Some(ExpandExcerptDirection::Down)
8069            } else {
8070                None
8071            }
8072            .map(|direction| ExpandInfo {
8073                direction,
8074                excerpt_id: region.excerpt.id,
8075            })
8076        };
8077
8078        let result = Some(RowInfo {
8079            buffer_id: Some(region.buffer.remote_id()),
8080            buffer_row: Some(buffer_point.row),
8081            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8082            diff_status: region
8083                .diff_hunk_status
8084                .filter(|_| self.point < region.range.end),
8085            expand_info,
8086            wrapped_buffer_row: None,
8087        });
8088        self.point += Point::new(1, 0);
8089        result
8090    }
8091}
8092
8093impl<'a> MultiBufferChunks<'a> {
8094    pub fn offset(&self) -> MultiBufferOffset {
8095        self.range.start
8096    }
8097
8098    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8099        self.diff_transforms.seek(&range.end, Bias::Right);
8100        let mut excerpt_end = self.diff_transforms.start().1;
8101        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8102            let overshoot = range.end - self.diff_transforms.start().0;
8103            excerpt_end += overshoot;
8104        }
8105
8106        self.diff_transforms.seek(&range.start, Bias::Right);
8107        let mut excerpt_start = self.diff_transforms.start().1;
8108        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8109            let overshoot = range.start - self.diff_transforms.start().0;
8110            excerpt_start += overshoot;
8111        }
8112
8113        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8114        self.buffer_chunk.take();
8115        self.range = range;
8116    }
8117
8118    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8119        self.excerpt_offset_range = new_range.clone();
8120        self.excerpts.seek(&new_range.start, Bias::Right);
8121        if let Some(excerpt) = self.excerpts.item() {
8122            let excerpt_start = *self.excerpts.start();
8123            if let Some(excerpt_chunks) = self
8124                .excerpt_chunks
8125                .as_mut()
8126                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8127            {
8128                excerpt.seek_chunks(
8129                    excerpt_chunks,
8130                    (self.excerpt_offset_range.start - excerpt_start)
8131                        ..(self.excerpt_offset_range.end - excerpt_start),
8132                );
8133            } else {
8134                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8135                    (self.excerpt_offset_range.start - excerpt_start)
8136                        ..(self.excerpt_offset_range.end - excerpt_start),
8137                    self.language_aware,
8138                ));
8139            }
8140        } else {
8141            self.excerpt_chunks = None;
8142        }
8143    }
8144
8145    #[ztracing::instrument(skip_all)]
8146    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8147        loop {
8148            if self.excerpt_offset_range.is_empty() {
8149                return None;
8150            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8151                self.excerpt_offset_range.start += chunk.text.len();
8152                return Some(chunk);
8153            } else {
8154                self.excerpts.next();
8155                let excerpt = self.excerpts.item()?;
8156                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8157                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8158                    self.language_aware,
8159                ));
8160            }
8161        }
8162    }
8163}
8164
8165impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8166    type Item = &'a str;
8167
8168    fn next(&mut self) -> Option<Self::Item> {
8169        let mut region = self.cursor.region()?;
8170        if self.offset == region.range.start {
8171            self.cursor.prev();
8172            region = self.cursor.region()?;
8173            let start_overshoot = self.start.saturating_sub(region.range.start);
8174            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8175                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8176            ));
8177        }
8178
8179        if self.offset == region.range.end && region.has_trailing_newline {
8180            self.offset -= 1;
8181            Some("\n")
8182        } else {
8183            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8184            self.offset -= chunk.len();
8185            Some(chunk)
8186        }
8187    }
8188}
8189
8190impl<'a> Iterator for MultiBufferChunks<'a> {
8191    type Item = Chunk<'a>;
8192
8193    #[ztracing::instrument(skip_all)]
8194    fn next(&mut self) -> Option<Chunk<'a>> {
8195        if self.range.start >= self.range.end {
8196            return None;
8197        }
8198        if self.range.start == self.diff_transforms.end().0 {
8199            self.diff_transforms.next();
8200        }
8201
8202        let diff_transform_start = self.diff_transforms.start().0;
8203        let diff_transform_end = self.diff_transforms.end().0;
8204        debug_assert!(
8205            self.range.start < diff_transform_end,
8206            "{:?} < {:?} of ({1:?}..{2:?})",
8207            self.range.start,
8208            diff_transform_end,
8209            diff_transform_start
8210        );
8211
8212        let diff_transform = self.diff_transforms.item()?;
8213        match diff_transform {
8214            DiffTransform::BufferContent { .. } => {
8215                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8216                    chunk
8217                } else {
8218                    let chunk = self.next_excerpt_chunk().unwrap();
8219                    self.buffer_chunk.insert(chunk)
8220                };
8221
8222                let chunk_end = self.range.start + chunk.text.len();
8223                let diff_transform_end = diff_transform_end.min(self.range.end);
8224
8225                if diff_transform_end < chunk_end {
8226                    let split_idx = diff_transform_end - self.range.start;
8227                    let (before, after) = chunk.text.split_at(split_idx);
8228                    self.range.start = diff_transform_end;
8229                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8230                    let chars = chunk.chars & mask;
8231                    let tabs = chunk.tabs & mask;
8232
8233                    chunk.text = after;
8234                    chunk.chars = chunk.chars >> split_idx;
8235                    chunk.tabs = chunk.tabs >> split_idx;
8236
8237                    Some(Chunk {
8238                        text: before,
8239                        chars,
8240                        tabs,
8241                        ..chunk.clone()
8242                    })
8243                } else {
8244                    self.range.start = chunk_end;
8245                    self.buffer_chunk.take()
8246                }
8247            }
8248            DiffTransform::DeletedHunk {
8249                buffer_id,
8250                base_text_byte_range,
8251                has_trailing_newline,
8252                ..
8253            } => {
8254                let base_text_start =
8255                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8256                let base_text_end =
8257                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8258                let base_text_end = base_text_end.min(base_text_byte_range.end);
8259
8260                let mut chunks = if let Some((_, mut chunks)) = self
8261                    .diff_base_chunks
8262                    .take()
8263                    .filter(|(id, _)| id == buffer_id)
8264                {
8265                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8266                    {
8267                        chunks.seek(base_text_start..base_text_end);
8268                    }
8269                    chunks
8270                } else {
8271                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8272                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8273                };
8274
8275                let chunk = if let Some(chunk) = chunks.next() {
8276                    self.range.start += chunk.text.len();
8277                    self.diff_base_chunks = Some((*buffer_id, chunks));
8278                    chunk
8279                } else {
8280                    debug_assert!(has_trailing_newline);
8281                    self.range.start += "\n".len();
8282                    Chunk {
8283                        text: "\n",
8284                        chars: 1u128,
8285                        ..Default::default()
8286                    }
8287                };
8288                Some(chunk)
8289            }
8290        }
8291    }
8292}
8293
8294impl MultiBufferBytes<'_> {
8295    fn consume(&mut self, len: usize) {
8296        self.range.start += len;
8297        self.chunk = &self.chunk[len..];
8298
8299        if !self.range.is_empty() && self.chunk.is_empty() {
8300            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8301                self.chunk = chunk;
8302            } else if self.has_trailing_newline {
8303                self.has_trailing_newline = false;
8304                self.chunk = b"\n";
8305            } else {
8306                self.cursor.next();
8307                if let Some(region) = self.cursor.region() {
8308                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8309                        region.buffer_range.start
8310                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8311                                .min(region.buffer_range.end),
8312                    );
8313                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8314                    self.excerpt_bytes = Some(excerpt_bytes);
8315                    self.has_trailing_newline =
8316                        region.has_trailing_newline && self.range.end >= region.range.end;
8317                    if self.chunk.is_empty() && self.has_trailing_newline {
8318                        self.has_trailing_newline = false;
8319                        self.chunk = b"\n";
8320                    }
8321                }
8322            }
8323        }
8324    }
8325}
8326
8327impl<'a> Iterator for MultiBufferBytes<'a> {
8328    type Item = &'a [u8];
8329
8330    fn next(&mut self) -> Option<Self::Item> {
8331        let chunk = self.chunk;
8332        if chunk.is_empty() {
8333            None
8334        } else {
8335            self.consume(chunk.len());
8336            Some(chunk)
8337        }
8338    }
8339}
8340
8341impl io::Read for MultiBufferBytes<'_> {
8342    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8343        let len = cmp::min(buf.len(), self.chunk.len());
8344        buf[..len].copy_from_slice(&self.chunk[..len]);
8345        if len > 0 {
8346            self.consume(len);
8347        }
8348        Ok(len)
8349    }
8350}
8351
8352impl io::Read for ReversedMultiBufferBytes<'_> {
8353    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8354        let len = cmp::min(buf.len(), self.chunk.len());
8355        buf[..len].copy_from_slice(&self.chunk[..len]);
8356        buf[..len].reverse();
8357        if len > 0 {
8358            self.range.end -= len;
8359            self.chunk = &self.chunk[..self.chunk.len() - len];
8360            if !self.range.is_empty()
8361                && self.chunk.is_empty()
8362                && let Some(chunk) = self.chunks.next()
8363            {
8364                self.chunk = chunk.as_bytes();
8365            }
8366        }
8367        Ok(len)
8368    }
8369}
8370
8371impl<'a> Iterator for ExcerptChunks<'a> {
8372    type Item = Chunk<'a>;
8373
8374    fn next(&mut self) -> Option<Self::Item> {
8375        if let Some(chunk) = self.content_chunks.next() {
8376            return Some(chunk);
8377        }
8378
8379        if self.has_footer {
8380            let text = "\n";
8381            let chars = 0b1;
8382            self.has_footer = false;
8383            return Some(Chunk {
8384                text,
8385                chars,
8386                ..Default::default()
8387            });
8388        }
8389
8390        None
8391    }
8392}
8393
8394impl ToOffset for Point {
8395    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8396        snapshot.point_to_offset(*self)
8397    }
8398    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8399        snapshot.point_to_offset_utf16(*self)
8400    }
8401}
8402
8403impl ToOffset for MultiBufferOffset {
8404    #[track_caller]
8405    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8406        assert!(
8407            *self <= snapshot.len(),
8408            "offset {} is greater than the snapshot.len() {}",
8409            self.0,
8410            snapshot.len().0,
8411        );
8412        *self
8413    }
8414    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8415        snapshot.offset_to_offset_utf16(*self)
8416    }
8417}
8418
8419impl ToOffset for MultiBufferOffsetUtf16 {
8420    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8421        snapshot.offset_utf16_to_offset(*self)
8422    }
8423
8424    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8425        *self
8426    }
8427}
8428
8429impl ToOffset for PointUtf16 {
8430    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8431        snapshot.point_utf16_to_offset(*self)
8432    }
8433    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8434        snapshot.point_utf16_to_offset_utf16(*self)
8435    }
8436}
8437
8438impl ToPoint for MultiBufferOffset {
8439    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8440        snapshot.offset_to_point(*self)
8441    }
8442    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8443        snapshot.offset_to_point_utf16(*self)
8444    }
8445}
8446
8447impl ToPoint for Point {
8448    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8449        *self
8450    }
8451    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8452        snapshot.point_to_point_utf16(*self)
8453    }
8454}
8455
8456impl ToPoint for PointUtf16 {
8457    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8458        snapshot.point_utf16_to_point(*self)
8459    }
8460    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8461        *self
8462    }
8463}
8464
8465impl From<ExcerptId> for EntityId {
8466    fn from(id: ExcerptId) -> Self {
8467        EntityId::from(id.0 as u64)
8468    }
8469}
8470
8471#[cfg(debug_assertions)]
8472pub mod debug {
8473    use super::*;
8474
8475    pub trait ToMultiBufferDebugRanges {
8476        fn to_multi_buffer_debug_ranges(
8477            &self,
8478            snapshot: &MultiBufferSnapshot,
8479        ) -> Vec<Range<MultiBufferOffset>>;
8480    }
8481
8482    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8483        fn to_multi_buffer_debug_ranges(
8484            &self,
8485            snapshot: &MultiBufferSnapshot,
8486        ) -> Vec<Range<MultiBufferOffset>> {
8487            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8488        }
8489    }
8490
8491    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8492        fn to_multi_buffer_debug_ranges(
8493            &self,
8494            snapshot: &MultiBufferSnapshot,
8495        ) -> Vec<Range<MultiBufferOffset>> {
8496            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8497                .to_multi_buffer_debug_ranges(snapshot)
8498        }
8499    }
8500
8501    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8502        fn to_multi_buffer_debug_ranges(
8503            &self,
8504            snapshot: &MultiBufferSnapshot,
8505        ) -> Vec<Range<MultiBufferOffset>> {
8506            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8507        }
8508    }
8509
8510    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8511        fn to_multi_buffer_debug_ranges(
8512            &self,
8513            snapshot: &MultiBufferSnapshot,
8514        ) -> Vec<Range<MultiBufferOffset>> {
8515            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8516        }
8517    }
8518
8519    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8520        fn to_multi_buffer_debug_ranges(
8521            &self,
8522            snapshot: &MultiBufferSnapshot,
8523        ) -> Vec<Range<MultiBufferOffset>> {
8524            self.iter()
8525                .map(|item| {
8526                    let offset = item.to_offset(snapshot);
8527                    offset..offset
8528                })
8529                .collect()
8530        }
8531    }
8532
8533    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8534        fn to_multi_buffer_debug_ranges(
8535            &self,
8536            snapshot: &MultiBufferSnapshot,
8537        ) -> Vec<Range<MultiBufferOffset>> {
8538            self.iter()
8539                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8540                .collect()
8541        }
8542    }
8543}