multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunk,
  14    DiffHunkSecondaryStatus, DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::PathKey;
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    excerpts: Vec<Locator>,
 519    _subscriptions: [gpui::Subscription; 2],
 520}
 521
 522struct DiffState {
 523    diff: Entity<BufferDiff>,
 524    is_inverted: bool,
 525    _subscription: gpui::Subscription,
 526}
 527
 528impl DiffState {
 529    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 530        DiffStateSnapshot {
 531            diff: self.diff.read(cx).snapshot(cx),
 532            is_inverted: self.is_inverted,
 533        }
 534    }
 535}
 536
 537#[derive(Clone)]
 538struct DiffStateSnapshot {
 539    diff: BufferDiffSnapshot,
 540    is_inverted: bool,
 541}
 542
 543impl std::ops::Deref for DiffStateSnapshot {
 544    type Target = BufferDiffSnapshot;
 545
 546    fn deref(&self) -> &Self::Target {
 547        &self.diff
 548    }
 549}
 550
 551impl DiffState {
 552    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 553        DiffState {
 554            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 555                BufferDiffEvent::DiffChanged(DiffChanged {
 556                    changed_range,
 557                    base_text_changed_range: _,
 558                    extended_range,
 559                }) => {
 560                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 561                    let range = if use_extended {
 562                        extended_range.clone()
 563                    } else {
 564                        changed_range.clone()
 565                    };
 566                    if let Some(range) = range {
 567                        this.buffer_diff_changed(diff, range, cx)
 568                    }
 569                    cx.emit(Event::BufferDiffChanged);
 570                }
 571                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 572                _ => {}
 573            }),
 574            diff,
 575            is_inverted: false,
 576        }
 577    }
 578
 579    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 580        DiffState {
 581            _subscription: cx.subscribe(&diff, {
 582                move |this, diff, event, cx| match event {
 583                    BufferDiffEvent::DiffChanged(DiffChanged {
 584                        changed_range: _,
 585                        base_text_changed_range,
 586                        extended_range: _,
 587                    }) => {
 588                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 589                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 590                        }
 591                        cx.emit(Event::BufferDiffChanged);
 592                    }
 593                    BufferDiffEvent::LanguageChanged => {
 594                        this.inverted_buffer_diff_language_changed(diff, cx)
 595                    }
 596                    _ => {}
 597                }
 598            }),
 599            diff,
 600            is_inverted: true,
 601        }
 602    }
 603}
 604
 605/// The contents of a [`MultiBuffer`] at a single point in time.
 606#[derive(Clone, Default)]
 607pub struct MultiBufferSnapshot {
 608    excerpts: SumTree<Excerpt>,
 609    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 610    diff_transforms: SumTree<DiffTransform>,
 611    non_text_state_update_count: usize,
 612    edit_count: usize,
 613    is_dirty: bool,
 614    has_deleted_file: bool,
 615    has_conflict: bool,
 616    has_inverted_diff: bool,
 617    /// immutable fields
 618    singleton: bool,
 619    excerpt_ids: SumTree<ExcerptIdMapping>,
 620    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 621    trailing_excerpt_update_count: usize,
 622    all_diff_hunks_expanded: bool,
 623    show_deleted_hunks: bool,
 624    use_extended_diff_range: bool,
 625    show_headers: bool,
 626}
 627
 628// follower: None
 629// - BufferContent(Some)
 630// - BufferContent(None)
 631// - DeletedHunk
 632//
 633// follower: Some
 634// - BufferContent(Some)
 635// - BufferContent(None)
 636
 637#[derive(Debug, Clone)]
 638enum DiffTransform {
 639    // RealText
 640    BufferContent {
 641        summary: MBTextSummary,
 642        // modified_hunk_info
 643        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 644    },
 645    // ExpandedHunkText
 646    DeletedHunk {
 647        summary: TextSummary,
 648        buffer_id: BufferId,
 649        hunk_info: DiffTransformHunkInfo,
 650        base_text_byte_range: Range<usize>,
 651        has_trailing_newline: bool,
 652    },
 653}
 654
 655#[derive(Clone, Copy, Debug)]
 656struct DiffTransformHunkInfo {
 657    excerpt_id: ExcerptId,
 658    hunk_start_anchor: text::Anchor,
 659    hunk_secondary_status: DiffHunkSecondaryStatus,
 660    is_logically_deleted: bool,
 661}
 662
 663impl Eq for DiffTransformHunkInfo {}
 664
 665impl PartialEq for DiffTransformHunkInfo {
 666    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 667        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 668    }
 669}
 670
 671impl std::hash::Hash for DiffTransformHunkInfo {
 672    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 673        self.excerpt_id.hash(state);
 674        self.hunk_start_anchor.hash(state);
 675    }
 676}
 677
 678#[derive(Clone)]
 679pub struct ExcerptInfo {
 680    pub id: ExcerptId,
 681    pub buffer: 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: 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        while let Some((id, range)) = ranges.next() {
1853            let locator = Locator::between(&prev_locator, &next_locator);
1854            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1855                buffer_state.excerpts.insert(ix, locator.clone());
1856            }
1857            let range = ExcerptRange {
1858                context: buffer_snapshot.anchor_before(&range.context.start)
1859                    ..buffer_snapshot.anchor_after(&range.context.end),
1860                primary: buffer_snapshot.anchor_before(&range.primary.start)
1861                    ..buffer_snapshot.anchor_after(&range.primary.end),
1862            };
1863            excerpts.push((id, range.clone()));
1864            let excerpt = Excerpt::new(
1865                id,
1866                locator.clone(),
1867                buffer_id,
1868                buffer_snapshot.clone(),
1869                range,
1870                ranges.peek().is_some() || cursor.item().is_some(),
1871            );
1872            new_excerpts.push(excerpt, ());
1873            prev_locator = locator.clone();
1874
1875            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1876                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1877            }
1878            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1879        }
1880
1881        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1882
1883        let suffix = cursor.suffix();
1884        let changed_trailing_excerpt = suffix.is_empty();
1885        new_excerpts.append(suffix, ());
1886        drop(cursor);
1887        snapshot.excerpts = new_excerpts;
1888        snapshot.excerpt_ids = new_excerpt_ids;
1889        if changed_trailing_excerpt {
1890            snapshot.trailing_excerpt_update_count += 1;
1891        }
1892
1893        let edits = Self::sync_diff_transforms(
1894            &mut snapshot,
1895            vec![Edit {
1896                old: edit_start..edit_start,
1897                new: edit_start..edit_end,
1898            }],
1899            DiffChangeKind::BufferEdited,
1900        );
1901        if !edits.is_empty() {
1902            self.subscriptions.publish(edits);
1903        }
1904
1905        cx.emit(Event::Edited {
1906            edited_buffer: None,
1907        });
1908        cx.emit(Event::ExcerptsAdded {
1909            buffer,
1910            predecessor: prev_excerpt_id,
1911            excerpts,
1912        });
1913        cx.notify();
1914    }
1915
1916    pub fn clear(&mut self, cx: &mut Context<Self>) {
1917        self.sync_mut(cx);
1918        let ids = self.excerpt_ids();
1919        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1920        self.excerpts_by_path.clear();
1921        self.paths_by_excerpt.clear();
1922        let MultiBufferSnapshot {
1923            excerpts,
1924            diffs: _,
1925            diff_transforms: _,
1926            non_text_state_update_count: _,
1927            edit_count: _,
1928            is_dirty,
1929            has_deleted_file,
1930            has_conflict,
1931            has_inverted_diff,
1932            singleton: _,
1933            excerpt_ids: _,
1934            replaced_excerpts,
1935            trailing_excerpt_update_count,
1936            all_diff_hunks_expanded: _,
1937            show_deleted_hunks: _,
1938            use_extended_diff_range: _,
1939            show_headers: _,
1940        } = self.snapshot.get_mut();
1941        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1942        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1943        *excerpts = Default::default();
1944        *trailing_excerpt_update_count += 1;
1945        *is_dirty = false;
1946        *has_deleted_file = false;
1947        *has_conflict = false;
1948        *has_inverted_diff = false;
1949        replaced_excerpts.clear();
1950
1951        let edits = Self::sync_diff_transforms(
1952            self.snapshot.get_mut(),
1953            vec![Edit {
1954                old: start..prev_len,
1955                new: start..start,
1956            }],
1957            DiffChangeKind::BufferEdited,
1958        );
1959        if !edits.is_empty() {
1960            self.subscriptions.publish(edits);
1961        }
1962        cx.emit(Event::Edited {
1963            edited_buffer: None,
1964        });
1965        cx.emit(Event::ExcerptsRemoved {
1966            ids,
1967            removed_buffer_ids,
1968        });
1969        cx.notify();
1970    }
1971
1972    #[ztracing::instrument(skip_all)]
1973    pub fn excerpts_for_buffer(
1974        &self,
1975        buffer_id: BufferId,
1976        cx: &App,
1977    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1978        let mut excerpts = Vec::new();
1979        let snapshot = self.read(cx);
1980        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1981        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1982            for locator in locators {
1983                cursor.seek_forward(&Some(locator), Bias::Left);
1984                if let Some(excerpt) = cursor.item()
1985                    && excerpt.locator == *locator
1986                {
1987                    excerpts.push((excerpt.id, excerpt.range.clone()));
1988                }
1989            }
1990        }
1991
1992        excerpts
1993    }
1994
1995    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1996        let snapshot = self.read(cx);
1997        let mut excerpts = snapshot
1998            .excerpts
1999            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2000        let mut diff_transforms = snapshot
2001            .diff_transforms
2002            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2003        diff_transforms.next();
2004        let locators = self
2005            .buffers
2006            .get(&buffer_id)
2007            .into_iter()
2008            .flat_map(|state| &state.excerpts);
2009        let mut result = Vec::new();
2010        for locator in locators {
2011            excerpts.seek_forward(&Some(locator), Bias::Left);
2012            if let Some(excerpt) = excerpts.item()
2013                && excerpt.locator == *locator
2014            {
2015                let excerpt_start = excerpts.start().1;
2016                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2017
2018                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2019                let overshoot = excerpt_start - diff_transforms.start().0;
2020                let start = diff_transforms.start().1 + overshoot;
2021
2022                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2023                let overshoot = excerpt_end - diff_transforms.start().0;
2024                let end = diff_transforms.start().1 + overshoot;
2025
2026                result.push(start.0..end.0)
2027            }
2028        }
2029        result
2030    }
2031
2032    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2033        self.snapshot
2034            .borrow()
2035            .excerpts
2036            .iter()
2037            .map(|entry| entry.buffer_id)
2038            .collect()
2039    }
2040
2041    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2042        self.snapshot
2043            .borrow()
2044            .excerpts
2045            .iter()
2046            .map(|entry| entry.id)
2047            .collect()
2048    }
2049
2050    pub fn excerpt_containing(
2051        &self,
2052        position: impl ToOffset,
2053        cx: &App,
2054    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2055        let snapshot = self.read(cx);
2056        let offset = position.to_offset(&snapshot);
2057
2058        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2059        cursor.seek(&offset);
2060        cursor
2061            .excerpt()
2062            .or_else(|| snapshot.excerpts.last())
2063            .map(|excerpt| {
2064                (
2065                    excerpt.id,
2066                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2067                    excerpt.range.context.clone(),
2068                )
2069            })
2070    }
2071
2072    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2073        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2074            self.buffer(buffer_id)
2075        } else {
2076            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2077            Some(buffer)
2078        }
2079    }
2080
2081    // If point is at the end of the buffer, the last excerpt is returned
2082    pub fn point_to_buffer_offset<T: ToOffset>(
2083        &self,
2084        point: T,
2085        cx: &App,
2086    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2087        let snapshot = self.read(cx);
2088        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2089        Some((
2090            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2091            offset,
2092        ))
2093    }
2094
2095    // If point is at the end of the buffer, the last excerpt is returned
2096    pub fn point_to_buffer_point<T: ToPoint>(
2097        &self,
2098        point: T,
2099        cx: &App,
2100    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2101        let snapshot = self.read(cx);
2102        let (buffer, point, is_main_buffer) =
2103            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2104        Some((
2105            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2106            point,
2107            is_main_buffer,
2108        ))
2109    }
2110
2111    pub fn buffer_point_to_anchor(
2112        &self,
2113        buffer: &Entity<Buffer>,
2114        point: Point,
2115        cx: &App,
2116    ) -> Option<Anchor> {
2117        let mut found = None;
2118        let snapshot = buffer.read(cx).snapshot();
2119        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2120            let start = range.context.start.to_point(&snapshot);
2121            let end = range.context.end.to_point(&snapshot);
2122            if start <= point && point < end {
2123                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2124                break;
2125            }
2126            if point < start {
2127                found = Some((start, excerpt_id));
2128            }
2129            if point > end {
2130                found = Some((end, excerpt_id));
2131            }
2132        }
2133
2134        found.map(|(point, excerpt_id)| {
2135            let text_anchor = snapshot.anchor_after(point);
2136            Anchor::in_buffer(excerpt_id, text_anchor)
2137        })
2138    }
2139
2140    pub fn buffer_anchor_to_anchor(
2141        &self,
2142        buffer: &Entity<Buffer>,
2143        anchor: text::Anchor,
2144        cx: &App,
2145    ) -> Option<Anchor> {
2146        let snapshot = buffer.read(cx).snapshot();
2147        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2148            if range.context.start.cmp(&anchor, &snapshot).is_le()
2149                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2150            {
2151                return Some(Anchor::in_buffer(excerpt_id, anchor));
2152            }
2153        }
2154
2155        None
2156    }
2157
2158    pub fn remove_excerpts(
2159        &mut self,
2160        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2161        cx: &mut Context<Self>,
2162    ) {
2163        self.sync_mut(cx);
2164        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2165        if ids.is_empty() {
2166            return;
2167        }
2168        self.buffer_changed_since_sync.replace(true);
2169
2170        let mut snapshot = self.snapshot.get_mut();
2171        let mut new_excerpts = SumTree::default();
2172        let mut cursor = snapshot
2173            .excerpts
2174            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2175        let mut edits = Vec::new();
2176        let mut excerpt_ids = ids.iter().copied().peekable();
2177        let mut removed_buffer_ids = Vec::new();
2178
2179        while let Some(excerpt_id) = excerpt_ids.next() {
2180            self.paths_by_excerpt.remove(&excerpt_id);
2181            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2182            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2183            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2184
2185            if let Some(mut excerpt) = cursor.item() {
2186                if excerpt.id != excerpt_id {
2187                    continue;
2188                }
2189                let mut old_start = cursor.start().1;
2190
2191                // Skip over the removed excerpt.
2192                'remove_excerpts: loop {
2193                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2194                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2195                        if buffer_state.excerpts.is_empty() {
2196                            log::debug!(
2197                                "removing buffer and diff for buffer {}",
2198                                excerpt.buffer_id
2199                            );
2200                            self.buffers.remove(&excerpt.buffer_id);
2201                            removed_buffer_ids.push(excerpt.buffer_id);
2202                        }
2203                    }
2204                    cursor.next();
2205
2206                    // Skip over any subsequent excerpts that are also removed.
2207                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2208                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2209                        if let Some(next_excerpt) = cursor.item()
2210                            && next_excerpt.locator == *next_locator
2211                        {
2212                            excerpt_ids.next();
2213                            excerpt = next_excerpt;
2214                            continue 'remove_excerpts;
2215                        }
2216                    }
2217
2218                    break;
2219                }
2220
2221                // When removing the last excerpt, remove the trailing newline from
2222                // the previous excerpt.
2223                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2224                    old_start -= 1;
2225                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2226                }
2227
2228                // Push an edit for the removal of this run of excerpts.
2229                let old_end = cursor.start().1;
2230                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2231                edits.push(Edit {
2232                    old: old_start..old_end,
2233                    new: new_start..new_start,
2234                });
2235            }
2236        }
2237        let suffix = cursor.suffix();
2238        let changed_trailing_excerpt = suffix.is_empty();
2239        new_excerpts.append(suffix, ());
2240        drop(cursor);
2241        snapshot.excerpts = new_excerpts;
2242        for buffer_id in &removed_buffer_ids {
2243            self.diffs.remove(buffer_id);
2244            snapshot.diffs.remove(buffer_id);
2245        }
2246
2247        // Recalculate has_inverted_diff after removing diffs
2248        if !removed_buffer_ids.is_empty() {
2249            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2250        }
2251
2252        if changed_trailing_excerpt {
2253            snapshot.trailing_excerpt_update_count += 1;
2254        }
2255
2256        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2257        if !edits.is_empty() {
2258            self.subscriptions.publish(edits);
2259        }
2260        cx.emit(Event::Edited {
2261            edited_buffer: None,
2262        });
2263        cx.emit(Event::ExcerptsRemoved {
2264            ids,
2265            removed_buffer_ids,
2266        });
2267        cx.notify();
2268    }
2269
2270    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2271        &self,
2272        anchors: Anchors,
2273        cx: &mut Context<Self>,
2274    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2275        let mut error = None;
2276        let mut futures = Vec::new();
2277        for anchor in anchors {
2278            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2279                if let Some(buffer) = self.buffers.get(&buffer_id) {
2280                    buffer.buffer.update(cx, |buffer, _| {
2281                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2282                    });
2283                } else {
2284                    error = Some(anyhow!(
2285                        "buffer {buffer_id} is not part of this multi-buffer"
2286                    ));
2287                    break;
2288                }
2289            }
2290        }
2291        async move {
2292            if let Some(error) = error {
2293                Err(error)?;
2294            }
2295            for future in futures {
2296                future.await?;
2297            }
2298            Ok(())
2299        }
2300    }
2301
2302    pub fn text_anchor_for_position<T: ToOffset>(
2303        &self,
2304        position: T,
2305        cx: &App,
2306    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2307        let snapshot = self.read(cx);
2308        let anchor = snapshot.anchor_before(position);
2309        let buffer = self
2310            .buffers
2311            .get(&anchor.text_anchor.buffer_id?)?
2312            .buffer
2313            .clone();
2314        Some((buffer, anchor.text_anchor))
2315    }
2316
2317    fn on_buffer_event(
2318        &mut self,
2319        buffer: Entity<Buffer>,
2320        event: &language::BufferEvent,
2321        cx: &mut Context<Self>,
2322    ) {
2323        use language::BufferEvent;
2324        let buffer_id = buffer.read(cx).remote_id();
2325        cx.emit(match event {
2326            BufferEvent::Edited => Event::Edited {
2327                edited_buffer: Some(buffer),
2328            },
2329            BufferEvent::DirtyChanged => Event::DirtyChanged,
2330            BufferEvent::Saved => Event::Saved,
2331            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2332            BufferEvent::Reloaded => Event::Reloaded,
2333            BufferEvent::LanguageChanged(has_language) => {
2334                Event::LanguageChanged(buffer_id, *has_language)
2335            }
2336            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2337            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2338            BufferEvent::CapabilityChanged => {
2339                self.capability = buffer.read(cx).capability();
2340                return;
2341            }
2342            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2343        });
2344    }
2345
2346    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2347        let diff = diff.read(cx);
2348        let buffer_id = diff.buffer_id;
2349        let diff = DiffStateSnapshot {
2350            diff: diff.snapshot(cx),
2351            is_inverted: false,
2352        };
2353        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2354    }
2355
2356    fn inverted_buffer_diff_language_changed(
2357        &mut self,
2358        diff: Entity<BufferDiff>,
2359        cx: &mut Context<Self>,
2360    ) {
2361        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2362        let diff = diff.read(cx);
2363        let diff = DiffStateSnapshot {
2364            diff: diff.snapshot(cx),
2365            is_inverted: true,
2366        };
2367        self.snapshot
2368            .get_mut()
2369            .diffs
2370            .insert(base_text_buffer_id, diff);
2371    }
2372
2373    fn buffer_diff_changed(
2374        &mut self,
2375        diff: Entity<BufferDiff>,
2376        range: Range<text::Anchor>,
2377        cx: &mut Context<Self>,
2378    ) {
2379        self.sync_mut(cx);
2380
2381        let diff = diff.read(cx);
2382        let buffer_id = diff.buffer_id;
2383
2384        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2385            return;
2386        };
2387        let new_diff = DiffStateSnapshot {
2388            diff: diff.snapshot(cx),
2389            is_inverted: false,
2390        };
2391        let mut snapshot = self.snapshot.get_mut();
2392        let base_text_changed = snapshot
2393            .diffs
2394            .get(&buffer_id)
2395            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2396        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2397
2398        let buffer = buffer_state.buffer.read(cx);
2399        let diff_change_range = range.to_offset(buffer);
2400
2401        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2402        let edits = Self::sync_diff_transforms(
2403            &mut snapshot,
2404            excerpt_edits,
2405            DiffChangeKind::DiffUpdated {
2406                base_changed: base_text_changed,
2407            },
2408        );
2409        if !edits.is_empty() {
2410            self.subscriptions.publish(edits);
2411        }
2412        cx.emit(Event::Edited {
2413            edited_buffer: None,
2414        });
2415    }
2416
2417    fn inverted_buffer_diff_changed(
2418        &mut self,
2419        diff: Entity<BufferDiff>,
2420        diff_change_range: Range<usize>,
2421        cx: &mut Context<Self>,
2422    ) {
2423        self.sync_mut(cx);
2424
2425        let diff = diff.read(cx);
2426        let base_text_buffer_id = diff.base_text(cx).remote_id();
2427        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2428            return;
2429        };
2430
2431        let new_diff = DiffStateSnapshot {
2432            diff: diff.snapshot(cx),
2433            is_inverted: true,
2434        };
2435        let mut snapshot = self.snapshot.get_mut();
2436        snapshot
2437            .diffs
2438            .insert_or_replace(base_text_buffer_id, new_diff);
2439
2440        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2441        let edits = Self::sync_diff_transforms(
2442            &mut snapshot,
2443            excerpt_edits,
2444            DiffChangeKind::DiffUpdated {
2445                // We don't read this field for inverted diffs.
2446                base_changed: false,
2447            },
2448        );
2449        if !edits.is_empty() {
2450            self.subscriptions.publish(edits);
2451        }
2452        cx.emit(Event::Edited {
2453            edited_buffer: None,
2454        });
2455    }
2456
2457    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2458        self.buffers.values().map(|state| state.buffer.clone())
2459    }
2460
2461    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2462        self.all_buffers_iter().collect()
2463    }
2464
2465    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2466        self.buffers.keys().copied()
2467    }
2468
2469    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2470        self.all_buffer_ids_iter().collect()
2471    }
2472
2473    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2474        self.buffers
2475            .get(&buffer_id)
2476            .map(|state| state.buffer.clone())
2477    }
2478
2479    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2480        self.point_to_buffer_offset(point, cx)
2481            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2482    }
2483
2484    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2485        let buffer_id = self
2486            .snapshot
2487            .borrow()
2488            .excerpts
2489            .first()
2490            .map(|excerpt| excerpt.buffer.remote_id());
2491        buffer_id
2492            .and_then(|buffer_id| self.buffer(buffer_id))
2493            .map(|buffer| {
2494                let buffer = buffer.read(cx);
2495                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2496            })
2497            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2498    }
2499
2500    pub fn language_settings_at<'a, T: ToOffset>(
2501        &'a self,
2502        point: T,
2503        cx: &'a App,
2504    ) -> Cow<'a, LanguageSettings> {
2505        let mut language = None;
2506        let mut file = None;
2507        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2508            let buffer = buffer.read(cx);
2509            language = buffer.language_at(offset);
2510            file = buffer.file();
2511        }
2512        language_settings(language.map(|l| l.name()), file, cx)
2513    }
2514
2515    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2516        self.buffers.values().for_each(|state| f(&state.buffer))
2517    }
2518
2519    pub fn explicit_title(&self) -> Option<&str> {
2520        self.title.as_deref()
2521    }
2522
2523    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2524        if let Some(title) = self.title.as_ref() {
2525            return title.into();
2526        }
2527
2528        if let Some(buffer) = self.as_singleton() {
2529            let buffer = buffer.read(cx);
2530
2531            if let Some(file) = buffer.file() {
2532                return file.file_name(cx).into();
2533            }
2534
2535            if let Some(title) = self.buffer_content_title(buffer) {
2536                return title;
2537            }
2538        };
2539
2540        "untitled".into()
2541    }
2542
2543    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2544        let mut is_leading_whitespace = true;
2545        let mut count = 0;
2546        let mut prev_was_space = false;
2547        let mut title = String::new();
2548
2549        for ch in buffer.snapshot().chars() {
2550            if is_leading_whitespace && ch.is_whitespace() {
2551                continue;
2552            }
2553
2554            is_leading_whitespace = false;
2555
2556            if ch == '\n' || count >= 40 {
2557                break;
2558            }
2559
2560            if ch.is_whitespace() {
2561                if !prev_was_space {
2562                    title.push(' ');
2563                    count += 1;
2564                    prev_was_space = true;
2565                }
2566            } else {
2567                title.push(ch);
2568                count += 1;
2569                prev_was_space = false;
2570            }
2571        }
2572
2573        let title = title.trim_end().to_string();
2574
2575        if title.is_empty() {
2576            return None;
2577        }
2578
2579        Some(title.into())
2580    }
2581
2582    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2583        self.title = Some(title);
2584        cx.notify();
2585    }
2586
2587    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2588    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2589        for buffer_state in self.buffers.values() {
2590            buffer_state
2591                .buffer
2592                .update(cx, |buffer, _cx| buffer.refresh_preview());
2593        }
2594    }
2595
2596    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2597    pub fn preserve_preview(&self, cx: &App) -> bool {
2598        self.buffers
2599            .values()
2600            .all(|state| state.buffer.read(cx).preserve_preview())
2601    }
2602
2603    #[cfg(any(test, feature = "test-support"))]
2604    pub fn is_parsing(&self, cx: &App) -> bool {
2605        self.as_singleton().unwrap().read(cx).is_parsing()
2606    }
2607
2608    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2609        let buffer_id = diff.read(cx).buffer_id;
2610
2611        if let Some(existing_diff) = self.diff_for(buffer_id)
2612            && diff.entity_id() == existing_diff.entity_id()
2613        {
2614            return;
2615        }
2616
2617        self.buffer_diff_changed(
2618            diff.clone(),
2619            text::Anchor::min_max_range_for_buffer(buffer_id),
2620            cx,
2621        );
2622        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2623    }
2624
2625    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2626        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2627        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2628        self.snapshot.get_mut().has_inverted_diff = true;
2629        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2630        self.diffs
2631            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2632    }
2633
2634    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2635        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2636    }
2637
2638    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2639        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2640    }
2641
2642    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2643        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2644    }
2645
2646    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2647        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2648        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2649    }
2650
2651    pub fn all_diff_hunks_expanded(&self) -> bool {
2652        self.snapshot.borrow().all_diff_hunks_expanded
2653    }
2654
2655    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2656        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2657        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2658    }
2659
2660    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2661        self.snapshot.get_mut().show_deleted_hunks = show;
2662        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2663    }
2664
2665    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2666        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2667    }
2668
2669    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2670        self.read(cx)
2671            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2672            .nth(1)
2673            .is_some()
2674    }
2675
2676    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2677        let snapshot = self.read(cx);
2678        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2679        let offset_range = range.to_offset(&snapshot);
2680        cursor.seek(&offset_range.start, Bias::Left);
2681        while let Some(item) = cursor.item() {
2682            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2683                break;
2684            }
2685            if item.hunk_info().is_some() {
2686                return true;
2687            }
2688            cursor.next();
2689        }
2690        false
2691    }
2692
2693    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2694        let snapshot = self.read(cx);
2695        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2696        for range in ranges {
2697            let range = range.to_point(&snapshot);
2698            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2699            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2700                .min(snapshot.len());
2701            cursor.seek(&start, Bias::Right);
2702            while let Some(item) = cursor.item() {
2703                if *cursor.start() >= end {
2704                    break;
2705                }
2706                if item.hunk_info().is_some() {
2707                    return true;
2708                }
2709                cursor.next();
2710            }
2711        }
2712        false
2713    }
2714
2715    pub fn expand_or_collapse_diff_hunks_inner(
2716        &mut self,
2717        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2718        expand: bool,
2719        cx: &mut Context<Self>,
2720    ) {
2721        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2722            return;
2723        }
2724        self.sync_mut(cx);
2725        let mut snapshot = self.snapshot.get_mut();
2726        let mut excerpt_edits = Vec::new();
2727        let mut last_hunk_row = None;
2728        for (range, end_excerpt_id) in ranges {
2729            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2730                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2731                    continue;
2732                }
2733                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2734                    continue;
2735                }
2736                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2737                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2738                let start = snapshot.excerpt_offset_for_anchor(&start);
2739                let end = snapshot.excerpt_offset_for_anchor(&end);
2740                last_hunk_row = Some(diff_hunk.row_range.start);
2741                excerpt_edits.push(text::Edit {
2742                    old: start..end,
2743                    new: start..end,
2744                });
2745            }
2746        }
2747
2748        let edits = Self::sync_diff_transforms(
2749            &mut snapshot,
2750            excerpt_edits,
2751            DiffChangeKind::ExpandOrCollapseHunks { expand },
2752        );
2753        if !edits.is_empty() {
2754            self.subscriptions.publish(edits);
2755        }
2756        cx.emit(Event::DiffHunksToggled);
2757        cx.emit(Event::Edited {
2758            edited_buffer: None,
2759        });
2760    }
2761
2762    pub fn expand_or_collapse_diff_hunks(
2763        &mut self,
2764        ranges: Vec<Range<Anchor>>,
2765        expand: bool,
2766        cx: &mut Context<Self>,
2767    ) {
2768        let snapshot = self.snapshot.borrow().clone();
2769        let ranges = ranges.iter().map(move |range| {
2770            let end_excerpt_id = range.end.excerpt_id;
2771            let range = range.to_point(&snapshot);
2772            let mut peek_end = range.end;
2773            if range.end.row < snapshot.max_row().0 {
2774                peek_end = Point::new(range.end.row + 1, 0);
2775            };
2776            (range.start..peek_end, end_excerpt_id)
2777        });
2778        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2779    }
2780
2781    pub fn resize_excerpt(
2782        &mut self,
2783        id: ExcerptId,
2784        range: Range<text::Anchor>,
2785        cx: &mut Context<Self>,
2786    ) {
2787        self.sync_mut(cx);
2788
2789        let mut snapshot = self.snapshot.get_mut();
2790        let locator = snapshot.excerpt_locator_for_id(id);
2791        let mut new_excerpts = SumTree::default();
2792        let mut cursor = snapshot
2793            .excerpts
2794            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2795        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2796
2797        let prefix = cursor.slice(&Some(locator), Bias::Left);
2798        new_excerpts.append(prefix, ());
2799
2800        let mut excerpt = cursor.item().unwrap().clone();
2801        let old_text_len = excerpt.text_summary.len;
2802
2803        excerpt.range.context.start = range.start;
2804        excerpt.range.context.end = range.end;
2805        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2806
2807        excerpt.text_summary = excerpt
2808            .buffer
2809            .text_summary_for_range(excerpt.range.context.clone());
2810
2811        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2812        let old_start_offset = cursor.start().1;
2813        let new_text_len = excerpt.text_summary.len;
2814        let edit = Edit {
2815            old: old_start_offset..old_start_offset + old_text_len,
2816            new: new_start_offset..new_start_offset + new_text_len,
2817        };
2818
2819        if let Some(last_edit) = edits.last_mut() {
2820            if last_edit.old.end == edit.old.start {
2821                last_edit.old.end = edit.old.end;
2822                last_edit.new.end = edit.new.end;
2823            } else {
2824                edits.push(edit);
2825            }
2826        } else {
2827            edits.push(edit);
2828        }
2829
2830        new_excerpts.push(excerpt, ());
2831
2832        cursor.next();
2833
2834        new_excerpts.append(cursor.suffix(), ());
2835
2836        drop(cursor);
2837        snapshot.excerpts = new_excerpts;
2838
2839        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2840        if !edits.is_empty() {
2841            self.subscriptions.publish(edits);
2842        }
2843        cx.emit(Event::Edited {
2844            edited_buffer: None,
2845        });
2846        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2847        cx.notify();
2848    }
2849
2850    pub fn expand_excerpts(
2851        &mut self,
2852        ids: impl IntoIterator<Item = ExcerptId>,
2853        line_count: u32,
2854        direction: ExpandExcerptDirection,
2855        cx: &mut Context<Self>,
2856    ) {
2857        if line_count == 0 {
2858            return;
2859        }
2860        self.sync_mut(cx);
2861        if !self.excerpts_by_path.is_empty() {
2862            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2863            return;
2864        }
2865        let mut snapshot = self.snapshot.get_mut();
2866
2867        let ids = ids.into_iter().collect::<Vec<_>>();
2868        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2869        let mut new_excerpts = SumTree::default();
2870        let mut cursor = snapshot
2871            .excerpts
2872            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2873        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2874
2875        for locator in &locators {
2876            let prefix = cursor.slice(&Some(locator), Bias::Left);
2877            new_excerpts.append(prefix, ());
2878
2879            let mut excerpt = cursor.item().unwrap().clone();
2880            let old_text_len = excerpt.text_summary.len;
2881
2882            let up_line_count = if direction.should_expand_up() {
2883                line_count
2884            } else {
2885                0
2886            };
2887
2888            let start_row = excerpt
2889                .range
2890                .context
2891                .start
2892                .to_point(&excerpt.buffer)
2893                .row
2894                .saturating_sub(up_line_count);
2895            let start_point = Point::new(start_row, 0);
2896            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2897
2898            let down_line_count = if direction.should_expand_down() {
2899                line_count
2900            } else {
2901                0
2902            };
2903
2904            let mut end_point = excerpt.buffer.clip_point(
2905                excerpt.range.context.end.to_point(&excerpt.buffer)
2906                    + Point::new(down_line_count, 0),
2907                Bias::Left,
2908            );
2909            end_point.column = excerpt.buffer.line_len(end_point.row);
2910            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2911            excerpt.max_buffer_row = end_point.row;
2912
2913            excerpt.text_summary = excerpt
2914                .buffer
2915                .text_summary_for_range(excerpt.range.context.clone());
2916
2917            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2918            let old_start_offset = cursor.start().1;
2919            let new_text_len = excerpt.text_summary.len;
2920            let edit = Edit {
2921                old: old_start_offset..old_start_offset + old_text_len,
2922                new: new_start_offset..new_start_offset + new_text_len,
2923            };
2924
2925            if let Some(last_edit) = edits.last_mut() {
2926                if last_edit.old.end == edit.old.start {
2927                    last_edit.old.end = edit.old.end;
2928                    last_edit.new.end = edit.new.end;
2929                } else {
2930                    edits.push(edit);
2931                }
2932            } else {
2933                edits.push(edit);
2934            }
2935
2936            new_excerpts.push(excerpt, ());
2937
2938            cursor.next();
2939        }
2940
2941        new_excerpts.append(cursor.suffix(), ());
2942
2943        drop(cursor);
2944        snapshot.excerpts = new_excerpts;
2945
2946        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2947        if !edits.is_empty() {
2948            self.subscriptions.publish(edits);
2949        }
2950        cx.emit(Event::Edited {
2951            edited_buffer: None,
2952        });
2953        cx.emit(Event::ExcerptsExpanded { ids });
2954        cx.notify();
2955    }
2956
2957    #[ztracing::instrument(skip_all)]
2958    fn sync(&self, cx: &App) {
2959        let changed = self.buffer_changed_since_sync.replace(false);
2960        if !changed {
2961            return;
2962        }
2963        let edits = Self::sync_from_buffer_changes(
2964            &mut self.snapshot.borrow_mut(),
2965            &self.buffers,
2966            &self.diffs,
2967            cx,
2968        );
2969        if !edits.is_empty() {
2970            self.subscriptions.publish(edits);
2971        }
2972    }
2973
2974    fn sync_mut(&mut self, cx: &App) {
2975        let changed = self.buffer_changed_since_sync.replace(false);
2976        if !changed {
2977            return;
2978        }
2979        let edits =
2980            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2981
2982        if !edits.is_empty() {
2983            self.subscriptions.publish(edits);
2984        }
2985    }
2986
2987    fn sync_from_buffer_changes(
2988        snapshot: &mut MultiBufferSnapshot,
2989        buffers: &BTreeMap<BufferId, BufferState>,
2990        diffs: &HashMap<BufferId, DiffState>,
2991        cx: &App,
2992    ) -> Vec<Edit<MultiBufferOffset>> {
2993        let MultiBufferSnapshot {
2994            excerpts,
2995            diffs: buffer_diff,
2996            diff_transforms: _,
2997            non_text_state_update_count,
2998            edit_count,
2999            is_dirty,
3000            has_deleted_file,
3001            has_conflict,
3002            has_inverted_diff: _,
3003            singleton: _,
3004            excerpt_ids: _,
3005            replaced_excerpts: _,
3006            trailing_excerpt_update_count: _,
3007            all_diff_hunks_expanded: _,
3008            show_deleted_hunks: _,
3009            use_extended_diff_range: _,
3010            show_headers: _,
3011        } = snapshot;
3012        *is_dirty = false;
3013        *has_deleted_file = false;
3014        *has_conflict = false;
3015
3016        let mut excerpts_to_edit = Vec::new();
3017        let mut non_text_state_updated = false;
3018        let mut edited = false;
3019        for buffer_state in buffers.values() {
3020            let buffer = buffer_state.buffer.read(cx);
3021            let version = buffer.version();
3022            let non_text_state_update_count = buffer.non_text_state_update_count();
3023
3024            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3025            let buffer_non_text_state_updated =
3026                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3027            if buffer_edited || buffer_non_text_state_updated {
3028                *buffer_state.last_version.borrow_mut() = version;
3029                buffer_state
3030                    .last_non_text_state_update_count
3031                    .set(non_text_state_update_count);
3032                excerpts_to_edit.extend(
3033                    buffer_state
3034                        .excerpts
3035                        .iter()
3036                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3037                );
3038            }
3039
3040            edited |= buffer_edited;
3041            non_text_state_updated |= buffer_non_text_state_updated;
3042            *is_dirty |= buffer.is_dirty();
3043            *has_deleted_file |= buffer
3044                .file()
3045                .is_some_and(|file| file.disk_state().is_deleted());
3046            *has_conflict |= buffer.has_conflict();
3047        }
3048        if edited {
3049            *edit_count += 1;
3050        }
3051        if non_text_state_updated {
3052            *non_text_state_update_count += 1;
3053        }
3054
3055        for (id, diff) in diffs.iter() {
3056            if buffer_diff.get(id).is_none() || diff.is_inverted {
3057                buffer_diff.insert(*id, diff.snapshot(cx));
3058            }
3059        }
3060
3061        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3062
3063        let mut edits = Vec::new();
3064        let mut new_excerpts = SumTree::default();
3065        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3066
3067        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3068            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3069            let old_excerpt = cursor.item().unwrap();
3070            let buffer = buffer.read(cx);
3071            let buffer_id = buffer.remote_id();
3072
3073            let mut new_excerpt;
3074            if buffer_edited {
3075                edits.extend(
3076                    buffer
3077                        .edits_since_in_range::<usize>(
3078                            old_excerpt.buffer.version(),
3079                            old_excerpt.range.context.clone(),
3080                        )
3081                        .map(|edit| {
3082                            let excerpt_old_start = cursor.start().1;
3083                            let excerpt_new_start =
3084                                ExcerptDimension(new_excerpts.summary().text.len);
3085                            let old_start = excerpt_old_start + edit.old.start;
3086                            let old_end = excerpt_old_start + edit.old.end;
3087                            let new_start = excerpt_new_start + edit.new.start;
3088                            let new_end = excerpt_new_start + edit.new.end;
3089                            Edit {
3090                                old: old_start..old_end,
3091                                new: new_start..new_end,
3092                            }
3093                        }),
3094                );
3095
3096                new_excerpt = Excerpt::new(
3097                    old_excerpt.id,
3098                    locator.clone(),
3099                    buffer_id,
3100                    buffer.snapshot(),
3101                    old_excerpt.range.clone(),
3102                    old_excerpt.has_trailing_newline,
3103                );
3104            } else {
3105                new_excerpt = old_excerpt.clone();
3106                new_excerpt.buffer = buffer.snapshot();
3107            }
3108
3109            new_excerpts.push(new_excerpt, ());
3110            cursor.next();
3111        }
3112        new_excerpts.append(cursor.suffix(), ());
3113
3114        drop(cursor);
3115        *excerpts = new_excerpts;
3116
3117        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3118    }
3119
3120    fn sync_diff_transforms(
3121        snapshot: &mut MultiBufferSnapshot,
3122        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3123        change_kind: DiffChangeKind,
3124    ) -> Vec<Edit<MultiBufferOffset>> {
3125        if excerpt_edits.is_empty() {
3126            return vec![];
3127        }
3128
3129        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3130        let mut old_diff_transforms = snapshot
3131            .diff_transforms
3132            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3133        let mut new_diff_transforms = SumTree::default();
3134        let mut old_expanded_hunks = HashSet::default();
3135        let mut output_edits = Vec::new();
3136        let mut output_delta = 0_isize;
3137        let mut at_transform_boundary = true;
3138        let mut end_of_current_insert = None;
3139
3140        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3141        while let Some(edit) = excerpt_edits.next() {
3142            excerpts.seek_forward(&edit.new.start, Bias::Right);
3143            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3144                excerpts.prev();
3145            }
3146
3147            // Keep any transforms that are before the edit.
3148            if at_transform_boundary {
3149                at_transform_boundary = false;
3150                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3151                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3152                if let Some(transform) = old_diff_transforms.item()
3153                    && old_diff_transforms.end().0 == edit.old.start
3154                    && old_diff_transforms.start().0 < edit.old.start
3155                {
3156                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3157                    old_diff_transforms.next();
3158                }
3159            }
3160
3161            // Compute the start of the edit in output coordinates.
3162            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3163            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3164            let edit_new_start =
3165                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3166
3167            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3168                &edit,
3169                &mut excerpts,
3170                &mut old_diff_transforms,
3171                &mut new_diff_transforms,
3172                &mut end_of_current_insert,
3173                &mut old_expanded_hunks,
3174                snapshot,
3175                change_kind,
3176            );
3177
3178            // Compute the end of the edit in output coordinates.
3179            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3180            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3181            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3182            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3183            let output_edit = Edit {
3184                old: edit_old_start..edit_old_end,
3185                new: edit_new_start..edit_new_end,
3186            };
3187
3188            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3189            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3190            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3191                output_edits.push(output_edit);
3192            }
3193
3194            // If this is the last edit that intersects the current diff transform,
3195            // then recreate the content up to the end of this transform, to prepare
3196            // for reusing additional slices of the old transforms.
3197            if excerpt_edits
3198                .peek()
3199                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3200            {
3201                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3202                    && match old_diff_transforms.item() {
3203                        Some(DiffTransform::BufferContent {
3204                            inserted_hunk_info: Some(hunk),
3205                            ..
3206                        }) => excerpts.item().is_some_and(|excerpt| {
3207                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3208                                && diff.is_inverted
3209                            {
3210                                return true;
3211                            }
3212                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3213                        }),
3214                        _ => true,
3215                    };
3216
3217                let mut excerpt_offset = edit.new.end;
3218                if !keep_next_old_transform {
3219                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3220                    old_diff_transforms.next();
3221                }
3222
3223                old_expanded_hunks.clear();
3224                Self::push_buffer_content_transform(
3225                    snapshot,
3226                    &mut new_diff_transforms,
3227                    excerpt_offset,
3228                    end_of_current_insert,
3229                );
3230                at_transform_boundary = true;
3231            }
3232        }
3233
3234        // Keep any transforms that are after the last edit.
3235        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3236
3237        // Ensure there's always at least one buffer content transform.
3238        if new_diff_transforms.is_empty() {
3239            new_diff_transforms.push(
3240                DiffTransform::BufferContent {
3241                    summary: Default::default(),
3242                    inserted_hunk_info: None,
3243                },
3244                (),
3245            );
3246        }
3247
3248        drop(old_diff_transforms);
3249        drop(excerpts);
3250        snapshot.diff_transforms = new_diff_transforms;
3251        snapshot.edit_count += 1;
3252
3253        #[cfg(any(test, feature = "test-support"))]
3254        snapshot.check_invariants();
3255        output_edits
3256    }
3257
3258    fn recompute_diff_transforms_for_edit(
3259        edit: &Edit<ExcerptOffset>,
3260        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3261        old_diff_transforms: &mut Cursor<
3262            DiffTransform,
3263            Dimensions<ExcerptOffset, MultiBufferOffset>,
3264        >,
3265        new_diff_transforms: &mut SumTree<DiffTransform>,
3266        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3267        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3268        snapshot: &MultiBufferSnapshot,
3269        change_kind: DiffChangeKind,
3270    ) -> bool {
3271        log::trace!(
3272            "recomputing diff transform for edit {:?} => {:?}",
3273            edit.old.start..edit.old.end,
3274            edit.new.start..edit.new.end
3275        );
3276
3277        // Record which hunks were previously expanded.
3278        while let Some(item) = old_diff_transforms.item() {
3279            if let Some(hunk_info) = item.hunk_info() {
3280                log::trace!(
3281                    "previously expanded hunk at {:?}",
3282                    old_diff_transforms.start()
3283                );
3284                old_expanded_hunks.insert(hunk_info);
3285            }
3286            if old_diff_transforms.end().0 > edit.old.end {
3287                break;
3288            }
3289            old_diff_transforms.next();
3290        }
3291
3292        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3293        // For inverted diffs, hunks are always shown, so we can't skip this.
3294        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3295        if old_expanded_hunks.is_empty()
3296            && change_kind == DiffChangeKind::BufferEdited
3297            && !all_diff_hunks_expanded
3298            && !snapshot.has_inverted_diff
3299        {
3300            return false;
3301        }
3302
3303        // Visit each excerpt that intersects the edit.
3304        let mut did_expand_hunks = false;
3305        while let Some(excerpt) = excerpts.item() {
3306            // Recompute the expanded hunks in the portion of the excerpt that
3307            // intersects the edit.
3308            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3309                let buffer = &excerpt.buffer;
3310                let excerpt_start = *excerpts.start();
3311                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3312                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3313                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3314                let edit_buffer_start =
3315                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3316                let edit_buffer_end =
3317                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3318                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3319
3320                if diff.is_inverted {
3321                    for hunk in diff.hunks_intersecting_base_text_range(
3322                        edit_buffer_start..edit_buffer_end,
3323                        diff.original_buffer_snapshot(),
3324                    ) {
3325                        did_expand_hunks = true;
3326                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3327                        if hunk_buffer_range.start < excerpt_buffer_start {
3328                            log::trace!("skipping hunk that starts before excerpt");
3329                            continue;
3330                        }
3331                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3332                        let hunk_excerpt_start = excerpt_start
3333                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3334                        let hunk_excerpt_end = excerpt_end
3335                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3336                        Self::push_buffer_content_transform(
3337                            snapshot,
3338                            new_diff_transforms,
3339                            hunk_excerpt_start,
3340                            *end_of_current_insert,
3341                        );
3342                        if !hunk_buffer_range.is_empty() {
3343                            let hunk_info = DiffTransformHunkInfo {
3344                                excerpt_id: excerpt.id,
3345                                hunk_start_anchor: hunk.buffer_range.start,
3346                                hunk_secondary_status: hunk.secondary_status,
3347                                is_logically_deleted: true,
3348                            };
3349                            *end_of_current_insert =
3350                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3351                        }
3352                    }
3353                } else {
3354                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3355                        ..buffer.anchor_after(edit_buffer_end);
3356                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3357                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3358                            continue;
3359                        }
3360
3361                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3362                        if hunk_buffer_range.start < excerpt_buffer_start {
3363                            log::trace!("skipping hunk that starts before excerpt");
3364                            continue;
3365                        }
3366
3367                        let hunk_info = DiffTransformHunkInfo {
3368                            excerpt_id: excerpt.id,
3369                            hunk_start_anchor: hunk.buffer_range.start,
3370                            hunk_secondary_status: hunk.secondary_status,
3371                            is_logically_deleted: false,
3372                        };
3373
3374                        let hunk_excerpt_start = excerpt_start
3375                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3376                        let hunk_excerpt_end = excerpt_end
3377                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3378
3379                        Self::push_buffer_content_transform(
3380                            snapshot,
3381                            new_diff_transforms,
3382                            hunk_excerpt_start,
3383                            *end_of_current_insert,
3384                        );
3385
3386                        // For every existing hunk, determine if it was previously expanded
3387                        // and if it should currently be expanded.
3388                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3389                        let should_expand_hunk = match &change_kind {
3390                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3391                                was_previously_expanded || all_diff_hunks_expanded
3392                            }
3393                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3394                                let intersects = hunk_buffer_range.is_empty()
3395                                    || hunk_buffer_range.end > edit_buffer_start;
3396                                if *expand {
3397                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3398                                } else {
3399                                    !intersects
3400                                        && (was_previously_expanded || all_diff_hunks_expanded)
3401                                }
3402                            }
3403                            _ => was_previously_expanded || all_diff_hunks_expanded,
3404                        };
3405
3406                        if should_expand_hunk {
3407                            did_expand_hunks = true;
3408                            log::trace!(
3409                                "expanding hunk {:?}, excerpt:{:?}",
3410                                hunk_excerpt_start..hunk_excerpt_end,
3411                                excerpt.id
3412                            );
3413
3414                            if !hunk.diff_base_byte_range.is_empty()
3415                                && hunk_buffer_range.start >= edit_buffer_start
3416                                && hunk_buffer_range.start <= excerpt_buffer_end
3417                                && snapshot.show_deleted_hunks
3418                            {
3419                                let base_text = diff.base_text();
3420                                let mut text_cursor =
3421                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3422                                let mut base_text_summary = text_cursor
3423                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3424
3425                                let mut has_trailing_newline = false;
3426                                if base_text_summary.last_line_chars > 0 {
3427                                    base_text_summary += TextSummary::newline();
3428                                    has_trailing_newline = true;
3429                                }
3430
3431                                new_diff_transforms.push(
3432                                    DiffTransform::DeletedHunk {
3433                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3434                                        summary: base_text_summary,
3435                                        buffer_id: excerpt.buffer_id,
3436                                        hunk_info,
3437                                        has_trailing_newline,
3438                                    },
3439                                    (),
3440                                );
3441                            }
3442
3443                            if !hunk_buffer_range.is_empty() {
3444                                *end_of_current_insert =
3445                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3446                            }
3447                        }
3448                    }
3449                }
3450            }
3451
3452            if excerpts.end() <= edit.new.end {
3453                excerpts.next();
3454            } else {
3455                break;
3456            }
3457        }
3458
3459        did_expand_hunks || !old_expanded_hunks.is_empty()
3460    }
3461
3462    fn append_diff_transforms(
3463        new_transforms: &mut SumTree<DiffTransform>,
3464        subtree: SumTree<DiffTransform>,
3465    ) {
3466        if let Some(DiffTransform::BufferContent {
3467            inserted_hunk_info,
3468            summary,
3469        }) = subtree.first()
3470            && Self::extend_last_buffer_content_transform(
3471                new_transforms,
3472                *inserted_hunk_info,
3473                *summary,
3474            )
3475        {
3476            let mut cursor = subtree.cursor::<()>(());
3477            cursor.next();
3478            cursor.next();
3479            new_transforms.append(cursor.suffix(), ());
3480            return;
3481        }
3482        new_transforms.append(subtree, ());
3483    }
3484
3485    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3486        if let DiffTransform::BufferContent {
3487            inserted_hunk_info: inserted_hunk_anchor,
3488            summary,
3489        } = transform
3490            && Self::extend_last_buffer_content_transform(
3491                new_transforms,
3492                inserted_hunk_anchor,
3493                summary,
3494            )
3495        {
3496            return;
3497        }
3498        new_transforms.push(transform, ());
3499    }
3500
3501    fn push_buffer_content_transform(
3502        old_snapshot: &MultiBufferSnapshot,
3503        new_transforms: &mut SumTree<DiffTransform>,
3504        end_offset: ExcerptOffset,
3505        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3506    ) {
3507        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3508            (end_offset.min(insertion_end_offset), Some(hunk_info))
3509        });
3510        let unchanged_region = [(end_offset, None)];
3511
3512        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3513        {
3514            let start_offset = new_transforms.summary().excerpt_len();
3515            if end_offset <= start_offset {
3516                continue;
3517            }
3518            let summary_to_add = old_snapshot
3519                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3520
3521            if !Self::extend_last_buffer_content_transform(
3522                new_transforms,
3523                inserted_hunk_info,
3524                summary_to_add,
3525            ) {
3526                new_transforms.push(
3527                    DiffTransform::BufferContent {
3528                        summary: summary_to_add,
3529                        inserted_hunk_info,
3530                    },
3531                    (),
3532                )
3533            }
3534        }
3535    }
3536
3537    fn extend_last_buffer_content_transform(
3538        new_transforms: &mut SumTree<DiffTransform>,
3539        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3540        summary_to_add: MBTextSummary,
3541    ) -> bool {
3542        let mut did_extend = false;
3543        new_transforms.update_last(
3544            |last_transform| {
3545                if let DiffTransform::BufferContent {
3546                    summary,
3547                    inserted_hunk_info: inserted_hunk_anchor,
3548                } = last_transform
3549                    && *inserted_hunk_anchor == new_inserted_hunk_info
3550                {
3551                    *summary += summary_to_add;
3552                    did_extend = true;
3553                }
3554            },
3555            (),
3556        );
3557        did_extend
3558    }
3559}
3560
3561fn build_excerpt_ranges(
3562    ranges: impl IntoIterator<Item = Range<Point>>,
3563    context_line_count: u32,
3564    buffer_snapshot: &BufferSnapshot,
3565) -> Vec<ExcerptRange<Point>> {
3566    ranges
3567        .into_iter()
3568        .map(|range| {
3569            let start_row = range.start.row.saturating_sub(context_line_count);
3570            let start = Point::new(start_row, 0);
3571            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3572            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3573            ExcerptRange {
3574                context: start..end,
3575                primary: range,
3576            }
3577        })
3578        .collect()
3579}
3580
3581#[cfg(any(test, feature = "test-support"))]
3582impl MultiBuffer {
3583    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3584        let buffer = cx.new(|cx| Buffer::local(text, cx));
3585        cx.new(|cx| Self::singleton(buffer, cx))
3586    }
3587
3588    pub fn build_multi<const COUNT: usize>(
3589        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3590        cx: &mut gpui::App,
3591    ) -> Entity<Self> {
3592        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3593        for (text, ranges) in excerpts {
3594            let buffer = cx.new(|cx| Buffer::local(text, cx));
3595            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3596            multi.update(cx, |multi, cx| {
3597                multi.push_excerpts(buffer, excerpt_ranges, cx)
3598            });
3599        }
3600
3601        multi
3602    }
3603
3604    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3605        cx.new(|cx| Self::singleton(buffer, cx))
3606    }
3607
3608    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3609        cx.new(|cx| {
3610            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3611            let mutation_count = rng.random_range(1..=5);
3612            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3613            multibuffer
3614        })
3615    }
3616
3617    pub fn randomly_edit(
3618        &mut self,
3619        rng: &mut impl rand::Rng,
3620        edit_count: usize,
3621        cx: &mut Context<Self>,
3622    ) {
3623        use util::RandomCharIter;
3624
3625        let snapshot = self.read(cx);
3626        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3627        let mut last_end = None;
3628        for _ in 0..edit_count {
3629            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3630                break;
3631            }
3632
3633            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3634            let end =
3635                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3636            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3637            last_end = Some(end);
3638
3639            let mut range = start..end;
3640            if rng.random_bool(0.2) {
3641                mem::swap(&mut range.start, &mut range.end);
3642            }
3643
3644            let new_text_len = rng.random_range(0..10);
3645            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3646
3647            edits.push((range, new_text.into()));
3648        }
3649        log::info!("mutating multi-buffer with {:?}", edits);
3650        drop(snapshot);
3651
3652        self.edit(edits, None, cx);
3653    }
3654
3655    pub fn randomly_edit_excerpts(
3656        &mut self,
3657        rng: &mut impl rand::Rng,
3658        mutation_count: usize,
3659        cx: &mut Context<Self>,
3660    ) {
3661        use rand::prelude::*;
3662        use std::env;
3663        use util::RandomCharIter;
3664
3665        let max_excerpts = env::var("MAX_EXCERPTS")
3666            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3667            .unwrap_or(5);
3668
3669        let mut buffers = Vec::new();
3670        for _ in 0..mutation_count {
3671            if rng.random_bool(0.05) {
3672                log::info!("Clearing multi-buffer");
3673                self.clear(cx);
3674                continue;
3675            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3676                let ids = self.excerpt_ids();
3677                let mut excerpts = HashSet::default();
3678                for _ in 0..rng.random_range(0..ids.len()) {
3679                    excerpts.extend(ids.choose(rng).copied());
3680                }
3681
3682                let line_count = rng.random_range(0..5);
3683
3684                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3685
3686                self.expand_excerpts(
3687                    excerpts.iter().cloned(),
3688                    line_count,
3689                    ExpandExcerptDirection::UpAndDown,
3690                    cx,
3691                );
3692                continue;
3693            }
3694
3695            let excerpt_ids = self.excerpt_ids();
3696            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3697                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3698                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3699                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3700                    let buffer = buffers.last().unwrap().read(cx);
3701                    log::info!(
3702                        "Creating new buffer {} with text: {:?}",
3703                        buffer.remote_id(),
3704                        buffer.text()
3705                    );
3706                    buffers.last().unwrap().clone()
3707                } else {
3708                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3709                };
3710
3711                let buffer = buffer_handle.read(cx);
3712                let buffer_text = buffer.text();
3713                let ranges = (0..rng.random_range(0..5))
3714                    .map(|_| {
3715                        let end_ix =
3716                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3717                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3718                        ExcerptRange::new(start_ix..end_ix)
3719                    })
3720                    .collect::<Vec<_>>();
3721                log::info!(
3722                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3723                    buffer_handle.read(cx).remote_id(),
3724                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3725                    ranges
3726                        .iter()
3727                        .map(|r| &buffer_text[r.context.clone()])
3728                        .collect::<Vec<_>>()
3729                );
3730
3731                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3732                log::info!("Inserted with ids: {:?}", excerpt_id);
3733            } else {
3734                let remove_count = rng.random_range(1..=excerpt_ids.len());
3735                let mut excerpts_to_remove = excerpt_ids
3736                    .choose_multiple(rng, remove_count)
3737                    .cloned()
3738                    .collect::<Vec<_>>();
3739                let snapshot = self.snapshot.borrow();
3740                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3741                drop(snapshot);
3742                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3743                self.remove_excerpts(excerpts_to_remove, cx);
3744            }
3745        }
3746    }
3747
3748    pub fn randomly_mutate(
3749        &mut self,
3750        rng: &mut impl rand::Rng,
3751        mutation_count: usize,
3752        cx: &mut Context<Self>,
3753    ) {
3754        use rand::prelude::*;
3755
3756        if rng.random_bool(0.7) || self.singleton {
3757            let buffer = self
3758                .buffers
3759                .values()
3760                .choose(rng)
3761                .map(|state| state.buffer.clone());
3762
3763            if let Some(buffer) = buffer {
3764                buffer.update(cx, |buffer, cx| {
3765                    if rng.random() {
3766                        buffer.randomly_edit(rng, mutation_count, cx);
3767                    } else {
3768                        buffer.randomly_undo_redo(rng, cx);
3769                    }
3770                });
3771            } else {
3772                self.randomly_edit(rng, mutation_count, cx);
3773            }
3774        } else {
3775            self.randomly_edit_excerpts(rng, mutation_count, cx);
3776        }
3777
3778        self.check_invariants(cx);
3779    }
3780
3781    fn check_invariants(&self, cx: &App) {
3782        self.read(cx).check_invariants();
3783    }
3784}
3785
3786impl EventEmitter<Event> for MultiBuffer {}
3787
3788impl MultiBufferSnapshot {
3789    pub fn text(&self) -> String {
3790        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3791            .map(|chunk| chunk.text)
3792            .collect()
3793    }
3794
3795    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3796        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3797            .flat_map(|c| c.chars().rev())
3798    }
3799
3800    fn reversed_chunks_in_range(
3801        &self,
3802        range: Range<MultiBufferOffset>,
3803    ) -> ReversedMultiBufferChunks<'_> {
3804        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3805        cursor.seek(&range.end);
3806        let current_chunks = cursor.region().as_ref().map(|region| {
3807            let start_overshoot = range.start.saturating_sub(region.range.start);
3808            let end_overshoot = range.end - region.range.start;
3809            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3810            let start = region.buffer_range.start + start_overshoot;
3811            region.buffer.reversed_chunks_in_range(start..end)
3812        });
3813        ReversedMultiBufferChunks {
3814            cursor,
3815            current_chunks,
3816            start: range.start,
3817            offset: range.end,
3818        }
3819    }
3820
3821    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3822        let offset = position.to_offset(self);
3823        self.text_for_range(offset..self.len())
3824            .flat_map(|chunk| chunk.chars())
3825    }
3826
3827    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3828        self.chunks(range, false).map(|chunk| chunk.text)
3829    }
3830
3831    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3832        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3833            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3834    }
3835
3836    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3837    where
3838        T: ToOffset,
3839    {
3840        let position = position.to_offset(self);
3841        position == self.clip_offset(position, Bias::Left)
3842            && self
3843                .bytes_in_range(position..self.len())
3844                .flatten()
3845                .copied()
3846                .take(needle.len())
3847                .eq(needle.bytes())
3848    }
3849
3850    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3851        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3852    }
3853
3854    pub fn diff_hunks_in_range<T: ToPoint>(
3855        &self,
3856        range: Range<T>,
3857    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3858        let query_range = range.start.to_point(self)..range.end.to_point(self);
3859        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3860            let diff = self.diffs.get(&buffer.remote_id())?;
3861            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3862                if diff.is_inverted {
3863                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3864                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3865                    Box::new(
3866                        diff.hunks_intersecting_base_text_range(
3867                            buffer_start..buffer_end,
3868                            diff.original_buffer_snapshot(),
3869                        )
3870                        .map(move |hunk| (hunk, buffer, true)),
3871                    )
3872                } else {
3873                    let buffer_start = buffer.anchor_before(buffer_range.start);
3874                    let buffer_end = buffer.anchor_after(buffer_range.end);
3875                    Box::new(
3876                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3877                            .map(move |hunk| (hunk, buffer, false)),
3878                    )
3879                };
3880            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3881                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3882                    return None;
3883                }
3884                let range = if is_inverted {
3885                    hunk.diff_base_byte_range.to_point(&buffer)
3886                } else {
3887                    hunk.range.clone()
3888                };
3889                Some((range, (hunk, is_inverted)))
3890            }))
3891        })
3892        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3893            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3894            {
3895                return None;
3896            }
3897            let end_row = if range.end.column == 0 {
3898                range.end.row
3899            } else {
3900                range.end.row + 1
3901            };
3902
3903            let word_diffs =
3904                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3905                    .then(|| {
3906                        let mut word_diffs = Vec::new();
3907
3908                        if self.show_deleted_hunks || is_inverted {
3909                            let hunk_start_offset = if is_inverted {
3910                                Anchor::in_buffer(
3911                                    excerpt.id,
3912                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3913                                )
3914                                .to_offset(self)
3915                            } else {
3916                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3917                                    .to_offset(self)
3918                            };
3919
3920                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3921                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3922                            }));
3923                        }
3924
3925                        if !is_inverted {
3926                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3927                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3928                            }));
3929                        }
3930                        word_diffs
3931                    })
3932                    .unwrap_or_default();
3933
3934            let buffer_range = if is_inverted {
3935                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3936                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3937            } else {
3938                hunk.buffer_range.clone()
3939            };
3940            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3941                DiffHunkStatusKind::Deleted
3942            } else if hunk.diff_base_byte_range.is_empty() {
3943                DiffHunkStatusKind::Added
3944            } else {
3945                DiffHunkStatusKind::Modified
3946            };
3947            Some(MultiBufferDiffHunk {
3948                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3949                buffer_id: excerpt.buffer_id,
3950                excerpt_id: excerpt.id,
3951                buffer_range,
3952                word_diffs,
3953                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3954                    ..BufferOffset(hunk.diff_base_byte_range.end),
3955                status: DiffHunkStatus {
3956                    kind: status_kind,
3957                    secondary: hunk.secondary_status,
3958                },
3959            })
3960        })
3961    }
3962
3963    fn excerpts_for_range<T: ToOffset>(
3964        &self,
3965        range: Range<T>,
3966    ) -> impl Iterator<Item = &Excerpt> + '_ {
3967        let range = range.start.to_offset(self)..range.end.to_offset(self);
3968        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3969        cursor.seek(&range.start);
3970        std::iter::from_fn(move || {
3971            let region = cursor.region()?;
3972            if region.range.start > range.end
3973                || region.range.start == range.end && region.range.start > range.start
3974            {
3975                return None;
3976            }
3977            let excerpt = region.excerpt;
3978            cursor.next_excerpt();
3979            Some(excerpt)
3980        })
3981    }
3982
3983    pub fn excerpt_ids_for_range<T: ToOffset>(
3984        &self,
3985        range: Range<T>,
3986    ) -> impl Iterator<Item = ExcerptId> + '_ {
3987        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3988    }
3989
3990    pub fn buffer_ids_for_range<T: ToOffset>(
3991        &self,
3992        range: Range<T>,
3993    ) -> impl Iterator<Item = BufferId> + '_ {
3994        self.excerpts_for_range(range)
3995            .map(|excerpt| excerpt.buffer_id)
3996    }
3997
3998    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3999        &self,
4000        ranges: impl Iterator<Item = Range<T>>,
4001    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4002        ranges.flat_map(|range| {
4003            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4004                .into_iter()
4005        })
4006    }
4007
4008    pub fn range_to_buffer_ranges<R, T>(
4009        &self,
4010        range: R,
4011    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4012    where
4013        R: RangeBounds<T>,
4014        T: ToOffset,
4015    {
4016        let start = match range.start_bound() {
4017            Bound::Included(start) => start.to_offset(self),
4018            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4019            Bound::Unbounded => MultiBufferOffset::ZERO,
4020        };
4021        let end_bound = match range.end_bound() {
4022            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4023            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4024            Bound::Unbounded => Bound::Unbounded,
4025        };
4026        let bounds = (Bound::Included(start), end_bound);
4027
4028        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4029        cursor.seek(&start);
4030
4031        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
4032        while let Some(region) = cursor.region() {
4033            let dominated_by_end_bound = match end_bound {
4034                Bound::Included(end) => region.range.start > end,
4035                Bound::Excluded(end) => region.range.start >= end,
4036                Bound::Unbounded => false,
4037            };
4038            if dominated_by_end_bound {
4039                break;
4040            }
4041            if region.is_main_buffer {
4042                let start_overshoot = start.saturating_sub(region.range.start);
4043                let end_offset = match end_bound {
4044                    Bound::Included(end) | Bound::Excluded(end) => end,
4045                    Bound::Unbounded => region.range.end,
4046                };
4047                let end_overshoot = end_offset.saturating_sub(region.range.start);
4048                let start = region
4049                    .buffer_range
4050                    .end
4051                    .min(region.buffer_range.start + start_overshoot);
4052                let end = region
4053                    .buffer_range
4054                    .end
4055                    .min(region.buffer_range.start + end_overshoot);
4056                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
4057                    *excerpt_id == region.excerpt.id && prev_range.end == start
4058                }) {
4059                    prev.1.end = end;
4060                } else {
4061                    result.push((region.buffer, start..end, region.excerpt.id));
4062                }
4063            }
4064            cursor.next();
4065        }
4066
4067        if let Some(excerpt) = cursor.excerpt() {
4068            let dominated_by_prev_excerpt =
4069                result.last().is_some_and(|(_, _, id)| *id == excerpt.id);
4070            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4071                let excerpt_position = self.len();
4072                if bounds.contains(&excerpt_position) {
4073                    let buffer_offset =
4074                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4075                    result.push((&excerpt.buffer, buffer_offset..buffer_offset, excerpt.id));
4076                }
4077            }
4078        }
4079
4080        result
4081    }
4082
4083    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4084        &self,
4085        range: Range<T>,
4086    ) -> impl Iterator<
4087        Item = (
4088            &BufferSnapshot,
4089            Range<BufferOffset>,
4090            ExcerptId,
4091            Option<Anchor>,
4092        ),
4093    > + '_ {
4094        let start = range.start.to_offset(self);
4095        let end = range.end.to_offset(self);
4096
4097        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4098        cursor.seek(&start);
4099
4100        std::iter::from_fn(move || {
4101            let region = cursor.region()?;
4102            if region.range.start > end {
4103                return None;
4104            }
4105            let start_overshoot = start.saturating_sub(region.range.start);
4106            let end_overshoot = end.saturating_sub(region.range.start);
4107            let start = region
4108                .buffer_range
4109                .end
4110                .min(region.buffer_range.start + start_overshoot);
4111            let end = region
4112                .buffer_range
4113                .end
4114                .min(region.buffer_range.start + end_overshoot);
4115
4116            let region_excerpt_id = region.excerpt.id;
4117            let deleted_hunk_anchor = if region.is_main_buffer {
4118                None
4119            } else {
4120                Some(self.anchor_before(region.range.start))
4121            };
4122            let result = (
4123                region.buffer,
4124                start..end,
4125                region_excerpt_id,
4126                deleted_hunk_anchor,
4127            );
4128            cursor.next();
4129            Some(result)
4130        })
4131    }
4132
4133    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4134    /// coordinates.
4135    ///
4136    /// The given callback will be called for every excerpt intersecting the given range. It will
4137    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4138    /// The callback should return an iterator of metadata items from that buffer, each paired
4139    /// with a buffer range.
4140    ///
4141    /// The returned iterator yields each of these metadata items, paired with its range in
4142    /// multi-buffer coordinates.
4143    fn lift_buffer_metadata<'a, MBD, M, I>(
4144        &'a self,
4145        query_range: Range<MBD>,
4146        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4147    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4148    where
4149        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4150        MBD: MultiBufferDimension
4151            + Ord
4152            + Sub<Output = MBD::TextDimension>
4153            + ops::Add<MBD::TextDimension, Output = MBD>
4154            + ops::AddAssign<MBD::TextDimension>,
4155        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4156            + ops::Add<Output = MBD::TextDimension>
4157            + AddAssign<MBD::TextDimension>
4158            + Ord,
4159    {
4160        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4161        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4162
4163        // Find the excerpt and buffer offset where the given range ends.
4164        cursor.seek(&query_range.end);
4165        let mut range_end = None;
4166        while let Some(region) = cursor.region() {
4167            if region.is_main_buffer {
4168                let mut buffer_end = region.buffer_range.start;
4169                let overshoot = if query_range.end > region.range.start {
4170                    query_range.end - region.range.start
4171                } else {
4172                    <MBD::TextDimension>::default()
4173                };
4174                buffer_end = buffer_end + overshoot;
4175                range_end = Some((region.excerpt.id, buffer_end));
4176                break;
4177            }
4178            cursor.next();
4179        }
4180
4181        cursor.seek(&query_range.start);
4182
4183        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4184            && region.range.start > MBD::default()
4185        {
4186            cursor.prev()
4187        } else if let Some(region) = cursor.region()
4188            && region.is_main_buffer
4189            && region.diff_hunk_status.is_some()
4190        {
4191            cursor.prev();
4192            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4193                cursor.next();
4194            }
4195        }
4196
4197        iter::from_fn(move || {
4198            loop {
4199                let excerpt = cursor.excerpt()?;
4200
4201                // If we have already retrieved metadata for this excerpt, continue to use it.
4202                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4203                    .as_mut()
4204                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4205                {
4206                    Some(metadata)
4207                }
4208                // Otherwise, compute the intersection of the input range with the excerpt's range,
4209                // and retrieve the metadata for the resulting range.
4210                else {
4211                    let region = cursor.region()?;
4212                    let mut buffer_start;
4213                    if region.is_main_buffer {
4214                        buffer_start = region.buffer_range.start;
4215                        if query_range.start > region.range.start {
4216                            let overshoot = query_range.start - region.range.start;
4217                            buffer_start = buffer_start + overshoot;
4218                        }
4219                        buffer_start = buffer_start.min(region.buffer_range.end);
4220                    } else {
4221                        buffer_start = cursor.main_buffer_position()?;
4222                    };
4223                    let mut buffer_end = excerpt
4224                        .range
4225                        .context
4226                        .end
4227                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4228                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4229                        && excerpt.id == end_excerpt_id
4230                    {
4231                        buffer_end = buffer_end.min(end_buffer_offset);
4232                    }
4233
4234                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4235                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4236                    })
4237                };
4238
4239                // Visit each metadata item.
4240                if let Some((metadata_buffer_range, metadata)) =
4241                    metadata_iter.and_then(Iterator::next)
4242                {
4243                    // Find the multibuffer regions that contain the start and end of
4244                    // the metadata item's range.
4245                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4246                        while let Some(region) = cursor.region() {
4247                            if (region.is_main_buffer
4248                                && (region.buffer_range.end >= metadata_buffer_range.start
4249                                    || cursor.is_at_end_of_excerpt()))
4250                                || (!region.is_main_buffer
4251                                    && region.buffer_range.start == metadata_buffer_range.start)
4252                            {
4253                                break;
4254                            }
4255                            cursor.next();
4256                        }
4257                    }
4258                    let start_region = cursor.region()?.clone();
4259                    while let Some(region) = cursor.region() {
4260                        if region.is_main_buffer
4261                            && (region.buffer_range.end > metadata_buffer_range.end
4262                                || cursor.is_at_end_of_excerpt())
4263                        {
4264                            break;
4265                        }
4266                        cursor.next();
4267                    }
4268                    let end_region = cursor.region();
4269
4270                    // Convert the metadata item's range into multibuffer coordinates.
4271                    let mut start_position = start_region.range.start;
4272                    let region_buffer_start = start_region.buffer_range.start;
4273                    if start_region.is_main_buffer
4274                        && metadata_buffer_range.start > region_buffer_start
4275                    {
4276                        start_position =
4277                            start_position + (metadata_buffer_range.start - region_buffer_start);
4278                        start_position = start_position.min(start_region.range.end);
4279                    }
4280
4281                    let mut end_position = self.max_position();
4282                    if let Some(end_region) = &end_region {
4283                        end_position = end_region.range.start;
4284                        debug_assert!(end_region.is_main_buffer);
4285                        let region_buffer_start = end_region.buffer_range.start;
4286                        if metadata_buffer_range.end > region_buffer_start {
4287                            end_position =
4288                                end_position + (metadata_buffer_range.end - region_buffer_start);
4289                        }
4290                        end_position = end_position.min(end_region.range.end);
4291                    }
4292
4293                    if start_position <= query_range.end && end_position >= query_range.start {
4294                        return Some((start_position..end_position, metadata, excerpt));
4295                    }
4296                }
4297                // When there are no more metadata items for this excerpt, move to the next excerpt.
4298                else {
4299                    current_excerpt_metadata.take();
4300                    if let Some((end_excerpt_id, _)) = range_end
4301                        && excerpt.id == end_excerpt_id
4302                    {
4303                        return None;
4304                    }
4305                    cursor.next_excerpt();
4306                }
4307            }
4308        })
4309    }
4310
4311    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4312        let offset = position.to_offset(self);
4313
4314        let mut cursor = self
4315            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4316            );
4317        cursor.seek(&DimensionPair {
4318            key: offset,
4319            value: None,
4320        });
4321        cursor.seek_to_start_of_current_excerpt();
4322        let excerpt = cursor.excerpt()?;
4323
4324        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4325        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4326        let current_position = self
4327            .anchor_before(offset)
4328            .text_anchor
4329            .to_offset(&excerpt.buffer);
4330
4331        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4332            if diff.is_inverted {
4333                for hunk in diff.hunks_intersecting_base_text_range_rev(
4334                    excerpt_start..excerpt_end,
4335                    diff.original_buffer_snapshot(),
4336                ) {
4337                    if hunk.diff_base_byte_range.end >= current_position {
4338                        continue;
4339                    }
4340                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4341                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4342                    return Some(MultiBufferRow(start.row));
4343                }
4344            } else {
4345                let excerpt_end = excerpt
4346                    .buffer
4347                    .anchor_before(excerpt_end.min(current_position));
4348                for hunk in diff.hunks_intersecting_range_rev(
4349                    excerpt.range.context.start..excerpt_end,
4350                    &excerpt.buffer,
4351                ) {
4352                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4353                    if hunk_end >= current_position {
4354                        continue;
4355                    }
4356                    let start =
4357                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4358                    return Some(MultiBufferRow(start.row));
4359                }
4360            }
4361        }
4362
4363        loop {
4364            cursor.prev_excerpt();
4365            let excerpt = cursor.excerpt()?;
4366
4367            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4368                continue;
4369            };
4370            if diff.is_inverted {
4371                let Some(hunk) = diff
4372                    .hunks_intersecting_base_text_range_rev(
4373                        excerpt.range.context.to_offset(&excerpt.buffer),
4374                        diff.original_buffer_snapshot(),
4375                    )
4376                    .next()
4377                else {
4378                    continue;
4379                };
4380                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4381                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4382                return Some(MultiBufferRow(start.row));
4383            } else {
4384                let Some(hunk) = diff
4385                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4386                    .next()
4387                else {
4388                    continue;
4389                };
4390                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4391                return Some(MultiBufferRow(start.row));
4392            }
4393        }
4394    }
4395
4396    pub fn has_diff_hunks(&self) -> bool {
4397        self.diffs.values().any(|diff| !diff.is_empty())
4398    }
4399
4400    pub fn is_inside_word<T: ToOffset>(
4401        &self,
4402        position: T,
4403        scope_context: Option<CharScopeContext>,
4404    ) -> bool {
4405        let position = position.to_offset(self);
4406        let classifier = self
4407            .char_classifier_at(position)
4408            .scope_context(scope_context);
4409        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4410        let prev_char_kind = self
4411            .reversed_chars_at(position)
4412            .next()
4413            .map(|c| classifier.kind(c));
4414        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4415    }
4416
4417    pub fn surrounding_word<T: ToOffset>(
4418        &self,
4419        start: T,
4420        scope_context: Option<CharScopeContext>,
4421    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4422        let mut start = start.to_offset(self);
4423        let mut end = start;
4424        let mut next_chars = self.chars_at(start).peekable();
4425        let mut prev_chars = self.reversed_chars_at(start).peekable();
4426
4427        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4428
4429        let word_kind = cmp::max(
4430            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4431            next_chars.peek().copied().map(|c| classifier.kind(c)),
4432        );
4433
4434        for ch in prev_chars {
4435            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4436                start -= ch.len_utf8();
4437            } else {
4438                break;
4439            }
4440        }
4441
4442        for ch in next_chars {
4443            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4444                end += ch.len_utf8();
4445            } else {
4446                break;
4447            }
4448        }
4449
4450        (start..end, word_kind)
4451    }
4452
4453    pub fn char_kind_before<T: ToOffset>(
4454        &self,
4455        start: T,
4456        scope_context: Option<CharScopeContext>,
4457    ) -> Option<CharKind> {
4458        let start = start.to_offset(self);
4459        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4460        self.reversed_chars_at(start)
4461            .next()
4462            .map(|ch| classifier.kind(ch))
4463    }
4464
4465    pub fn is_singleton(&self) -> bool {
4466        self.singleton
4467    }
4468
4469    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4470        if self.singleton {
4471            self.excerpts
4472                .iter()
4473                .next()
4474                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4475        } else {
4476            None
4477        }
4478    }
4479
4480    pub fn len(&self) -> MultiBufferOffset {
4481        self.diff_transforms.summary().output.len
4482    }
4483
4484    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4485        MBD::from_summary(&self.text_summary())
4486    }
4487
4488    pub fn is_empty(&self) -> bool {
4489        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4490    }
4491
4492    pub fn widest_line_number(&self) -> u32 {
4493        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4494        self.excerpts.summary().widest_line_number + 1
4495    }
4496
4497    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4498        let range = range.start.to_offset(self)..range.end.to_offset(self);
4499        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4500        excerpts.seek(&range.start);
4501
4502        let mut chunk;
4503        let mut has_trailing_newline;
4504        let excerpt_bytes;
4505        if let Some(region) = excerpts.region() {
4506            let mut bytes = region.buffer.bytes_in_range(
4507                region.buffer_range.start + (range.start - region.range.start)
4508                    ..(region.buffer_range.start + (range.end - region.range.start))
4509                        .min(region.buffer_range.end),
4510            );
4511            chunk = bytes.next().unwrap_or(&[][..]);
4512            excerpt_bytes = Some(bytes);
4513            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4514            if chunk.is_empty() && has_trailing_newline {
4515                chunk = b"\n";
4516                has_trailing_newline = false;
4517            }
4518        } else {
4519            chunk = &[][..];
4520            excerpt_bytes = None;
4521            has_trailing_newline = false;
4522        };
4523
4524        MultiBufferBytes {
4525            range,
4526            cursor: excerpts,
4527            excerpt_bytes,
4528            has_trailing_newline,
4529            chunk,
4530        }
4531    }
4532
4533    pub fn reversed_bytes_in_range<T: ToOffset>(
4534        &self,
4535        range: Range<T>,
4536    ) -> ReversedMultiBufferBytes<'_> {
4537        let range = range.start.to_offset(self)..range.end.to_offset(self);
4538        let mut chunks = self.reversed_chunks_in_range(range.clone());
4539        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4540        ReversedMultiBufferBytes {
4541            range,
4542            chunks,
4543            chunk,
4544        }
4545    }
4546
4547    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4548        let mut cursor = self.cursor::<Point, Point>();
4549        cursor.seek(&Point::new(start_row.0, 0));
4550        let mut result = MultiBufferRows {
4551            point: Point::new(0, 0),
4552            is_empty: self.excerpts.is_empty(),
4553            is_singleton: self.is_singleton(),
4554            cursor,
4555        };
4556        result.seek(start_row);
4557        result
4558    }
4559
4560    pub fn chunks<T: ToOffset>(
4561        &self,
4562        range: Range<T>,
4563        language_aware: bool,
4564    ) -> MultiBufferChunks<'_> {
4565        let mut chunks = MultiBufferChunks {
4566            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4567                ..ExcerptDimension(MultiBufferOffset::ZERO),
4568            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4569            excerpts: self.excerpts.cursor(()),
4570            diff_transforms: self.diff_transforms.cursor(()),
4571            diffs: &self.diffs,
4572            diff_base_chunks: None,
4573            excerpt_chunks: None,
4574            buffer_chunk: None,
4575            language_aware,
4576        };
4577        let range = range.start.to_offset(self)..range.end.to_offset(self);
4578        chunks.seek(range);
4579        chunks
4580    }
4581
4582    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4583        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4584    }
4585
4586    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4587        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4588    }
4589
4590    pub fn clip_offset_utf16(
4591        &self,
4592        offset: MultiBufferOffsetUtf16,
4593        bias: Bias,
4594    ) -> MultiBufferOffsetUtf16 {
4595        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4596    }
4597
4598    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4599        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4600            buffer.clip_point_utf16(Unclipped(point), bias)
4601        })
4602    }
4603
4604    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4605        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4606    }
4607
4608    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4609        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4610    }
4611
4612    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4613        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4614    }
4615
4616    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4617        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4618    }
4619
4620    #[instrument(skip_all)]
4621    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4622        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4623    }
4624
4625    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4626        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4627    }
4628
4629    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4630        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4631    }
4632
4633    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4634        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4635    }
4636
4637    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4638        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4639    }
4640
4641    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4642        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4643    }
4644
4645    fn clip_dimension<MBD, BD>(
4646        &self,
4647        position: MBD,
4648        bias: Bias,
4649        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4650    ) -> MBD
4651    where
4652        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4653        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4654    {
4655        let mut cursor = self.cursor::<MBD, BD>();
4656        cursor.seek(&position);
4657        if let Some(region) = cursor.region() {
4658            if position >= region.range.end {
4659                return region.range.end;
4660            }
4661            let overshoot = position - region.range.start;
4662            let mut buffer_position = region.buffer_range.start;
4663            buffer_position += overshoot;
4664            let clipped_buffer_position =
4665                clip_buffer_position(region.buffer, buffer_position, bias);
4666            let mut position = region.range.start;
4667            position += clipped_buffer_position - region.buffer_range.start;
4668            position
4669        } else {
4670            self.max_position()
4671        }
4672    }
4673
4674    #[instrument(skip_all)]
4675    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4676        &self,
4677        key: MBR1,
4678        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4679    ) -> MBR2
4680    where
4681        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4682        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4683        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4684        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4685    {
4686        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4687        cursor.seek(&DimensionPair { key, value: None });
4688        if let Some(region) = cursor.region() {
4689            if key >= region.range.end.key {
4690                return region.range.end.value.unwrap();
4691            }
4692            let start_key = region.range.start.key;
4693            let start_value = region.range.start.value.unwrap();
4694            let buffer_start_key = region.buffer_range.start.key;
4695            let buffer_start_value = region.buffer_range.start.value.unwrap();
4696            let mut buffer_key = buffer_start_key;
4697            buffer_key += key - start_key;
4698            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4699            let mut result = start_value;
4700            result += buffer_value - buffer_start_value;
4701            result
4702        } else {
4703            self.max_position()
4704        }
4705    }
4706
4707    pub fn point_to_buffer_offset<T: ToOffset>(
4708        &self,
4709        point: T,
4710    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4711        let offset = point.to_offset(self);
4712        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4713        cursor.seek(&offset);
4714        let region = cursor.region()?;
4715        let overshoot = offset - region.range.start;
4716        let buffer_offset = region.buffer_range.start + overshoot;
4717        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4718            && region.has_trailing_newline
4719            && !region.is_main_buffer
4720        {
4721            let main_buffer_position = cursor.main_buffer_position()?;
4722            let buffer_snapshot = &cursor.excerpt()?.buffer;
4723            return Some((buffer_snapshot, main_buffer_position));
4724        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4725            return None;
4726        }
4727        Some((region.buffer, buffer_offset))
4728    }
4729
4730    pub fn point_to_buffer_point(
4731        &self,
4732        point: Point,
4733    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4734        let mut cursor = self.cursor::<Point, Point>();
4735        cursor.seek(&point);
4736        let region = cursor.region()?;
4737        let overshoot = point - region.range.start;
4738        let buffer_point = region.buffer_range.start + overshoot;
4739        let excerpt = cursor.excerpt()?;
4740        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4741            && region.has_trailing_newline
4742            && !region.is_main_buffer
4743        {
4744            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4745        } else if buffer_point > region.buffer.max_point() {
4746            return None;
4747        }
4748        Some((region.buffer, buffer_point, excerpt.id))
4749    }
4750
4751    pub fn suggested_indents(
4752        &self,
4753        rows: impl IntoIterator<Item = u32>,
4754        cx: &App,
4755    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4756        let mut result = BTreeMap::new();
4757        self.suggested_indents_callback(
4758            rows,
4759            |row, indent| {
4760                result.insert(row, indent);
4761                ControlFlow::Continue(())
4762            },
4763            cx,
4764        );
4765        result
4766    }
4767
4768    // move this to be a generator once those are a thing
4769    pub fn suggested_indents_callback(
4770        &self,
4771        rows: impl IntoIterator<Item = u32>,
4772        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4773        cx: &App,
4774    ) {
4775        let mut rows_for_excerpt = Vec::new();
4776        let mut cursor = self.cursor::<Point, Point>();
4777        let mut rows = rows.into_iter().peekable();
4778        let mut prev_row = u32::MAX;
4779        let mut prev_language_indent_size = IndentSize::default();
4780
4781        while let Some(row) = rows.next() {
4782            cursor.seek(&Point::new(row, 0));
4783            let Some(region) = cursor.region() else {
4784                continue;
4785            };
4786
4787            // Retrieve the language and indent size once for each disjoint region being indented.
4788            let single_indent_size = if row.saturating_sub(1) == prev_row {
4789                prev_language_indent_size
4790            } else {
4791                region
4792                    .buffer
4793                    .language_indent_size_at(Point::new(row, 0), cx)
4794            };
4795            prev_language_indent_size = single_indent_size;
4796            prev_row = row;
4797
4798            let start_buffer_row = region.buffer_range.start.row;
4799            let start_multibuffer_row = region.range.start.row;
4800            let end_multibuffer_row = region.range.end.row;
4801
4802            rows_for_excerpt.push(row);
4803            while let Some(next_row) = rows.peek().copied() {
4804                if end_multibuffer_row > next_row {
4805                    rows_for_excerpt.push(next_row);
4806                    rows.next();
4807                } else {
4808                    break;
4809                }
4810            }
4811
4812            let buffer_rows = rows_for_excerpt
4813                .drain(..)
4814                .map(|row| start_buffer_row + row - start_multibuffer_row);
4815            let buffer_indents = region
4816                .buffer
4817                .suggested_indents(buffer_rows, single_indent_size);
4818            for (row, indent) in buffer_indents {
4819                if cb(
4820                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4821                    indent,
4822                )
4823                .is_break()
4824                {
4825                    return;
4826                }
4827            }
4828        }
4829    }
4830
4831    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4832        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4833            let mut size = buffer.indent_size_for_line(range.start.row);
4834            size.len = size
4835                .len
4836                .min(range.end.column)
4837                .saturating_sub(range.start.column);
4838            size
4839        } else {
4840            IndentSize::spaces(0)
4841        }
4842    }
4843
4844    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4845        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4846            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4847        } else {
4848            LineIndent::spaces(0)
4849        }
4850    }
4851
4852    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4853        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4854
4855        if self.language_settings(cx).extend_comment_on_newline
4856            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4857        {
4858            let delimiters = language_scope.line_comment_prefixes();
4859            for delimiter in delimiters {
4860                if *self
4861                    .chars_at(Point::new(row.0, indent.len() as u32))
4862                    .take(delimiter.chars().count())
4863                    .collect::<String>()
4864                    .as_str()
4865                    == **delimiter
4866                {
4867                    indent.push_str(delimiter);
4868                    break;
4869                }
4870            }
4871        }
4872
4873        indent
4874    }
4875
4876    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4877    where
4878        T: ToOffset,
4879    {
4880        for char in self.reversed_chars_at(position) {
4881            if !char.is_whitespace() {
4882                return false;
4883            }
4884            if char == '\n' {
4885                return true;
4886            }
4887        }
4888        true
4889    }
4890
4891    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4892        while row.0 > 0 {
4893            row.0 -= 1;
4894            if !self.is_line_blank(row) {
4895                return Some(row);
4896            }
4897        }
4898        None
4899    }
4900
4901    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4902        if let Some((_, range)) = self.buffer_line_for_row(row) {
4903            range.end.column - range.start.column
4904        } else {
4905            0
4906        }
4907    }
4908
4909    pub fn buffer_line_for_row(
4910        &self,
4911        row: MultiBufferRow,
4912    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4913        let mut cursor = self.cursor::<Point, Point>();
4914        let point = Point::new(row.0, 0);
4915        cursor.seek(&point);
4916        let region = cursor.region()?;
4917        let overshoot = point.min(region.range.end) - region.range.start;
4918        let buffer_point = region.buffer_range.start + overshoot;
4919        if buffer_point.row > region.buffer_range.end.row {
4920            return None;
4921        }
4922        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4923        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4924            .min(region.buffer_range.end);
4925        Some((region.buffer, line_start..line_end))
4926    }
4927
4928    pub fn max_point(&self) -> Point {
4929        self.text_summary().lines
4930    }
4931
4932    pub fn max_row(&self) -> MultiBufferRow {
4933        MultiBufferRow(self.text_summary().lines.row)
4934    }
4935
4936    pub fn text_summary(&self) -> MBTextSummary {
4937        self.diff_transforms.summary().output
4938    }
4939
4940    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4941    where
4942        MBD: MultiBufferDimension + AddAssign,
4943        O: ToOffset,
4944    {
4945        let range = range.start.to_offset(self)..range.end.to_offset(self);
4946        let mut cursor = self
4947            .diff_transforms
4948            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4949        cursor.seek(&range.start, Bias::Right);
4950
4951        let Some(first_transform) = cursor.item() else {
4952            return MBD::from_summary(&MBTextSummary::default());
4953        };
4954
4955        let diff_transform_start = cursor.start().0;
4956        let diff_transform_end = cursor.end().0;
4957        let diff_start = range.start;
4958        let start_overshoot = diff_start - diff_transform_start;
4959        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4960
4961        let mut result = match first_transform {
4962            DiffTransform::BufferContent { .. } => {
4963                let excerpt_start = cursor.start().1 + start_overshoot;
4964                let excerpt_end = cursor.start().1 + end_overshoot;
4965                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4966            }
4967            DiffTransform::DeletedHunk {
4968                buffer_id,
4969                base_text_byte_range,
4970                has_trailing_newline,
4971                ..
4972            } => {
4973                let buffer_start = base_text_byte_range.start + start_overshoot;
4974                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4975                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4976                    panic!("{:?} is in non-existent deleted hunk", range.start)
4977                };
4978
4979                let include_trailing_newline =
4980                    *has_trailing_newline && range.end >= diff_transform_end;
4981                if include_trailing_newline {
4982                    buffer_end -= 1;
4983                }
4984
4985                let mut summary = base_text
4986                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4987
4988                if include_trailing_newline {
4989                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4990                        &TextSummary::newline(),
4991                    ))
4992                }
4993
4994                let mut result = MBD::default();
4995                result.add_text_dim(&summary);
4996                result
4997            }
4998        };
4999        if range.end < diff_transform_end {
5000            return result;
5001        }
5002
5003        cursor.next();
5004        result.add_mb_text_summary(
5005            &cursor
5006                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5007                .0,
5008        );
5009
5010        let Some(last_transform) = cursor.item() else {
5011            return result;
5012        };
5013
5014        let overshoot = range.end - cursor.start().0;
5015        let suffix = match last_transform {
5016            DiffTransform::BufferContent { .. } => {
5017                let end = cursor.start().1 + overshoot;
5018                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5019            }
5020            DiffTransform::DeletedHunk {
5021                base_text_byte_range,
5022                buffer_id,
5023                has_trailing_newline,
5024                ..
5025            } => {
5026                let buffer_end = base_text_byte_range.start + overshoot;
5027                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5028                    panic!("{:?} is in non-existent deleted hunk", range.end)
5029                };
5030
5031                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5032                    base_text_byte_range.start..buffer_end,
5033                );
5034                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5035                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5036                        &TextSummary::from("\n"),
5037                    ))
5038                }
5039
5040                let mut result = MBD::default();
5041                result.add_text_dim(&suffix);
5042                result
5043            }
5044        };
5045
5046        result += suffix;
5047        result
5048    }
5049
5050    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5051    where
5052        MBD: MultiBufferDimension + AddAssign,
5053    {
5054        let mut summary = MBD::default();
5055        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5056        cursor.seek(&range.start, Bias::Right);
5057        if let Some(excerpt) = cursor.item() {
5058            let mut end_before_newline = cursor.end();
5059            if excerpt.has_trailing_newline {
5060                end_before_newline -= 1;
5061            }
5062
5063            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5064            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5065            let end_in_excerpt =
5066                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5067            summary.add_text_dim(
5068                &excerpt
5069                    .buffer
5070                    .text_summary_for_range::<MBD::TextDimension, _>(
5071                        start_in_excerpt..end_in_excerpt,
5072                    ),
5073            );
5074
5075            if range.end > end_before_newline {
5076                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5077            }
5078
5079            cursor.next();
5080        }
5081
5082        if range.end > *cursor.start() {
5083            summary += cursor
5084                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5085                .0;
5086            if let Some(excerpt) = cursor.item() {
5087                range.end = cmp::max(*cursor.start(), range.end);
5088
5089                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5090                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5091                summary.add_text_dim(
5092                    &excerpt
5093                        .buffer
5094                        .text_summary_for_range::<MBD::TextDimension, _>(
5095                            excerpt_start..end_in_excerpt,
5096                        ),
5097                );
5098            }
5099        }
5100
5101        summary
5102    }
5103
5104    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5105    where
5106        MBD: MultiBufferDimension
5107            + Ord
5108            + Sub<Output = MBD::TextDimension>
5109            + Sub<MBD::TextDimension, Output = MBD>
5110            + AddAssign<MBD::TextDimension>
5111            + Add<MBD::TextDimension, Output = MBD>,
5112        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5113    {
5114        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5115        let locator = self.excerpt_locator_for_id(excerpt_id);
5116        let (start, _, mut item) = self
5117            .excerpts
5118            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5119        let mut start = MBD::from_summary(&start.text);
5120        if item.is_none() && excerpt_id == ExcerptId::max() {
5121            item = self.excerpts.last();
5122            if let Some(last_summary) = self.excerpts.last_summary() {
5123                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5124            }
5125        }
5126
5127        if self.diff_transforms.is_empty() {
5128            let excerpt_start_position = ExcerptDimension(start);
5129            if let Some(excerpt) = item {
5130                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5131                    return excerpt_start_position.0;
5132                }
5133                let excerpt_buffer_start = excerpt
5134                    .range
5135                    .context
5136                    .start
5137                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5138                let excerpt_buffer_end = excerpt
5139                    .range
5140                    .context
5141                    .end
5142                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5143                let buffer_summary = anchor
5144                    .text_anchor
5145                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5146                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5147                let mut position = excerpt_start_position;
5148                if summary > excerpt_buffer_start {
5149                    position += summary - excerpt_buffer_start;
5150                }
5151
5152                position.0
5153            } else {
5154                excerpt_start_position.0
5155            }
5156        } else {
5157            let mut diff_transforms_cursor = self
5158                .diff_transforms
5159                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5160            diff_transforms_cursor.next();
5161
5162            let excerpt_start_position = ExcerptDimension(start);
5163            if let Some(excerpt) = item {
5164                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5165                    return self.resolve_summary_for_anchor(
5166                        &Anchor::min(),
5167                        excerpt_start_position,
5168                        &mut diff_transforms_cursor,
5169                    );
5170                }
5171                let excerpt_buffer_start = excerpt
5172                    .range
5173                    .context
5174                    .start
5175                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5176                let excerpt_buffer_end = excerpt
5177                    .range
5178                    .context
5179                    .end
5180                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5181                let buffer_summary = anchor
5182                    .text_anchor
5183                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5184                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5185                let mut position = excerpt_start_position;
5186                if summary > excerpt_buffer_start {
5187                    position += summary - excerpt_buffer_start;
5188                }
5189
5190                if diff_transforms_cursor.start().0 < position {
5191                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5192                }
5193                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5194            } else {
5195                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5196                self.resolve_summary_for_anchor(
5197                    &Anchor::max(),
5198                    excerpt_start_position,
5199                    &mut diff_transforms_cursor,
5200                )
5201            }
5202        }
5203    }
5204
5205    fn resolve_summary_for_anchor<MBD>(
5206        &self,
5207        anchor: &Anchor,
5208        excerpt_position: ExcerptDimension<MBD>,
5209        diff_transforms: &mut Cursor<
5210            DiffTransform,
5211            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5212        >,
5213    ) -> MBD
5214    where
5215        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5216    {
5217        loop {
5218            let transform_end_position = diff_transforms.end().0;
5219            let at_transform_end =
5220                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5221            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5222                diff_transforms.next();
5223                continue;
5224            }
5225
5226            let mut position = diff_transforms.start().1;
5227            match diff_transforms.item() {
5228                Some(DiffTransform::DeletedHunk {
5229                    buffer_id,
5230                    base_text_byte_range,
5231                    ..
5232                }) => {
5233                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5234                        && let Some(base_text) =
5235                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5236                        && diff_base_anchor.is_valid(&base_text)
5237                    {
5238                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5239                        if base_text_offset >= base_text_byte_range.start
5240                            && base_text_offset <= base_text_byte_range.end
5241                        {
5242                            let position_in_hunk = base_text
5243                                .text_summary_for_range::<MBD::TextDimension, _>(
5244                                    base_text_byte_range.start..base_text_offset,
5245                                );
5246                            position.0.add_text_dim(&position_in_hunk);
5247                        } else if at_transform_end {
5248                            diff_transforms.next();
5249                            continue;
5250                        }
5251                    }
5252                }
5253                _ => {
5254                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5255                        diff_transforms.next();
5256                        continue;
5257                    }
5258                    let overshoot = excerpt_position - diff_transforms.start().0;
5259                    position += overshoot;
5260                }
5261            }
5262
5263            return position.0;
5264        }
5265    }
5266
5267    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5268        let mut cursor = self
5269            .excerpts
5270            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5271        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5272
5273        cursor.seek(&Some(locator), Bias::Left);
5274        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5275            cursor.prev();
5276        }
5277
5278        let mut position = cursor.start().1;
5279        if let Some(excerpt) = cursor.item()
5280            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5281        {
5282            let excerpt_buffer_start = excerpt
5283                .buffer
5284                .offset_for_anchor(&excerpt.range.context.start);
5285            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5286            let buffer_position = cmp::min(
5287                excerpt_buffer_end,
5288                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5289            );
5290            if buffer_position > excerpt_buffer_start {
5291                position += buffer_position - excerpt_buffer_start;
5292            }
5293        }
5294        position
5295    }
5296
5297    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5298        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5299            excerpt_id = *replacement;
5300        }
5301        excerpt_id
5302    }
5303
5304    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5305    where
5306        MBD: MultiBufferDimension
5307            + Ord
5308            + Sub<Output = MBD::TextDimension>
5309            + AddAssign<MBD::TextDimension>,
5310        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5311        I: 'a + IntoIterator<Item = &'a Anchor>,
5312    {
5313        let mut anchors = anchors.into_iter().peekable();
5314        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5315        let mut diff_transforms_cursor = self
5316            .diff_transforms
5317            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5318        diff_transforms_cursor.next();
5319
5320        let mut summaries = Vec::new();
5321        while let Some(anchor) = anchors.peek() {
5322            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5323
5324            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5325                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5326            });
5327
5328            let locator = self.excerpt_locator_for_id(excerpt_id);
5329            cursor.seek_forward(locator, Bias::Left);
5330            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5331                cursor.prev();
5332            }
5333
5334            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5335            if let Some(excerpt) = cursor.item() {
5336                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5337                    let position = self.resolve_summary_for_anchor(
5338                        &Anchor::min(),
5339                        excerpt_start_position,
5340                        &mut diff_transforms_cursor,
5341                    );
5342                    summaries.extend(excerpt_anchors.map(|_| position));
5343                    continue;
5344                }
5345                let excerpt_buffer_start = excerpt
5346                    .range
5347                    .context
5348                    .start
5349                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5350                let excerpt_buffer_end = excerpt
5351                    .range
5352                    .context
5353                    .end
5354                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5355                for (buffer_summary, anchor) in excerpt
5356                    .buffer
5357                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5358                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5359                    )
5360                {
5361                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5362                    let mut position = excerpt_start_position;
5363                    if summary > excerpt_buffer_start {
5364                        position += summary - excerpt_buffer_start;
5365                    }
5366
5367                    if diff_transforms_cursor.start().0 < position {
5368                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5369                    }
5370
5371                    summaries.push(self.resolve_summary_for_anchor(
5372                        anchor,
5373                        position,
5374                        &mut diff_transforms_cursor,
5375                    ));
5376                }
5377            } else {
5378                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5379                let position = self.resolve_summary_for_anchor(
5380                    &Anchor::max(),
5381                    excerpt_start_position,
5382                    &mut diff_transforms_cursor,
5383                );
5384                summaries.extend(excerpt_anchors.map(|_| position));
5385            }
5386        }
5387
5388        summaries
5389    }
5390
5391    pub fn dimensions_from_points<'a, MBD>(
5392        &'a self,
5393        points: impl 'a + IntoIterator<Item = Point>,
5394    ) -> impl 'a + Iterator<Item = MBD>
5395    where
5396        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5397    {
5398        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5399        cursor.seek(&DimensionPair {
5400            key: Point::default(),
5401            value: None,
5402        });
5403        let mut points = points.into_iter();
5404        iter::from_fn(move || {
5405            let point = points.next()?;
5406
5407            cursor.seek_forward(&DimensionPair {
5408                key: point,
5409                value: None,
5410            });
5411
5412            if let Some(region) = cursor.region() {
5413                let overshoot = point - region.range.start.key;
5414                let buffer_point = region.buffer_range.start + overshoot;
5415                let mut position = region.range.start.value.unwrap();
5416                position.add_text_dim(
5417                    &region
5418                        .buffer
5419                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5420                );
5421                if point == region.range.end.key && region.has_trailing_newline {
5422                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5423                }
5424                Some(position)
5425            } else {
5426                Some(MBD::from_summary(&self.text_summary()))
5427            }
5428        })
5429    }
5430
5431    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5432    where
5433        I: 'a + IntoIterator<Item = &'a Anchor>,
5434    {
5435        let mut anchors = anchors.into_iter().enumerate().peekable();
5436        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5437        cursor.next();
5438
5439        let mut result = Vec::new();
5440
5441        while let Some((_, anchor)) = anchors.peek() {
5442            let old_excerpt_id = anchor.excerpt_id;
5443
5444            // Find the location where this anchor's excerpt should be.
5445            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5446            cursor.seek_forward(&Some(old_locator), Bias::Left);
5447
5448            let next_excerpt = cursor.item();
5449            let prev_excerpt = cursor.prev_item();
5450
5451            // Process all of the anchors for this excerpt.
5452            while let Some((anchor_ix, &anchor)) =
5453                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5454            {
5455                let mut anchor = anchor;
5456
5457                // Leave min and max anchors unchanged if invalid or
5458                // if the old excerpt still exists at this location
5459                let mut kept_position = next_excerpt
5460                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5461                    || old_excerpt_id == ExcerptId::max()
5462                    || old_excerpt_id == ExcerptId::min();
5463
5464                // If the old excerpt no longer exists at this location, then attempt to
5465                // find an equivalent position for this anchor in an adjacent excerpt.
5466                if !kept_position {
5467                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5468                        if excerpt.contains(&anchor) {
5469                            anchor.excerpt_id = excerpt.id;
5470                            kept_position = true;
5471                            break;
5472                        }
5473                    }
5474                }
5475
5476                // If there's no adjacent excerpt that contains the anchor's position,
5477                // then report that the anchor has lost its position.
5478                if !kept_position {
5479                    anchor = if let Some(excerpt) = next_excerpt {
5480                        let mut text_anchor = excerpt
5481                            .range
5482                            .context
5483                            .start
5484                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5485                        if text_anchor
5486                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5487                            .is_gt()
5488                        {
5489                            text_anchor = excerpt.range.context.end;
5490                        }
5491                        Anchor::in_buffer(excerpt.id, text_anchor)
5492                    } else if let Some(excerpt) = prev_excerpt {
5493                        let mut text_anchor = excerpt
5494                            .range
5495                            .context
5496                            .end
5497                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5498                        if text_anchor
5499                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5500                            .is_lt()
5501                        {
5502                            text_anchor = excerpt.range.context.start;
5503                        }
5504                        Anchor::in_buffer(excerpt.id, text_anchor)
5505                    } else if anchor.text_anchor.bias == Bias::Left {
5506                        Anchor::min()
5507                    } else {
5508                        Anchor::max()
5509                    };
5510                }
5511
5512                result.push((anchor_ix, anchor, kept_position));
5513            }
5514        }
5515        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5516        result
5517    }
5518
5519    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5520        self.anchor_at(position, Bias::Left)
5521    }
5522
5523    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5524        self.anchor_at(position, Bias::Right)
5525    }
5526
5527    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5528        let offset = position.to_offset(self);
5529
5530        // Find the given position in the diff transforms. Determine the corresponding
5531        // offset in the excerpts, and whether the position is within a deleted hunk.
5532        let mut diff_transforms = self
5533            .diff_transforms
5534            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5535        diff_transforms.seek(&offset, Bias::Right);
5536
5537        if offset == diff_transforms.start().0
5538            && bias == Bias::Left
5539            && let Some(prev_item) = diff_transforms.prev_item()
5540            && let DiffTransform::DeletedHunk { .. } = prev_item
5541        {
5542            diff_transforms.prev();
5543        }
5544        let offset_in_transform = offset - diff_transforms.start().0;
5545        let mut excerpt_offset = diff_transforms.start().1;
5546        let mut diff_base_anchor = None;
5547        if let Some(DiffTransform::DeletedHunk {
5548            buffer_id,
5549            base_text_byte_range,
5550            has_trailing_newline,
5551            ..
5552        }) = diff_transforms.item()
5553        {
5554            let diff = self.diffs.get(buffer_id).expect("missing diff");
5555            if offset_in_transform > base_text_byte_range.len() {
5556                debug_assert!(*has_trailing_newline);
5557                bias = Bias::Right;
5558            } else {
5559                diff_base_anchor = Some(
5560                    diff.base_text()
5561                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5562                );
5563                bias = Bias::Left;
5564            }
5565        } else {
5566            excerpt_offset += MultiBufferOffset(offset_in_transform);
5567        };
5568
5569        let mut excerpts = self
5570            .excerpts
5571            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5572        excerpts.seek(&excerpt_offset, Bias::Right);
5573        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5574            excerpts.prev();
5575        }
5576        if let Some(excerpt) = excerpts.item() {
5577            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5578            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5579                overshoot -= 1;
5580                bias = Bias::Right;
5581            }
5582
5583            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5584            let text_anchor =
5585                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5586            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5587            match diff_base_anchor {
5588                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5589                None => anchor,
5590            }
5591        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5592        {
5593            Anchor::min()
5594        } else {
5595            Anchor::max()
5596        }
5597    }
5598
5599    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5600    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5601        let (excerpt, buffer, _) = self.as_singleton()?;
5602        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5603            Some(Anchor::in_buffer(*excerpt, text_anchor))
5604        } else {
5605            None
5606        }
5607    }
5608
5609    /// Returns an anchor for the given excerpt and text anchor,
5610    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5611    pub fn anchor_range_in_excerpt(
5612        &self,
5613        excerpt_id: ExcerptId,
5614        text_anchor: Range<text::Anchor>,
5615    ) -> Option<Range<Anchor>> {
5616        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5617
5618        Some(
5619            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5620                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5621        )
5622    }
5623
5624    /// Returns an anchor for the given excerpt and text anchor,
5625    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5626    pub fn anchor_in_excerpt(
5627        &self,
5628        excerpt_id: ExcerptId,
5629        text_anchor: text::Anchor,
5630    ) -> Option<Anchor> {
5631        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5632        Self::anchor_in_excerpt_(excerpt, text_anchor)
5633    }
5634
5635    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5636    pub fn anchors_in_excerpt(
5637        &self,
5638        excerpt_id: ExcerptId,
5639        text_anchors: impl IntoIterator<Item = text::Anchor>,
5640    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5641        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5642        Some(
5643            text_anchors
5644                .into_iter()
5645                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5646        )
5647    }
5648
5649    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5650        match text_anchor.buffer_id {
5651            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5652            Some(_) => return None,
5653            None if text_anchor.is_max() || text_anchor.is_min() => {
5654                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5655            }
5656            None => return None,
5657        }
5658
5659        let context = &excerpt.range.context;
5660        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5661            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5662        {
5663            return None;
5664        }
5665
5666        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5667    }
5668
5669    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5670        Some(self.excerpt(excerpt_id)?.range.context.clone())
5671    }
5672
5673    pub fn excerpt_range_for_excerpt(
5674        &self,
5675        excerpt_id: ExcerptId,
5676    ) -> Option<ExcerptRange<text::Anchor>> {
5677        Some(self.excerpt(excerpt_id)?.range.clone())
5678    }
5679
5680    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5681        if anchor.is_min() || anchor.is_max() {
5682            // todo(lw): should be `!self.is_empty()`
5683            true
5684        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5685            excerpt.buffer.can_resolve(&anchor.text_anchor)
5686        } else {
5687            false
5688        }
5689    }
5690
5691    pub fn excerpts(
5692        &self,
5693    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5694        self.excerpts
5695            .iter()
5696            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5697    }
5698
5699    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5700    where
5701        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5702        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5703    {
5704        let excerpts = self.excerpts.cursor(());
5705        let diff_transforms = self.diff_transforms.cursor(());
5706        MultiBufferCursor {
5707            excerpts,
5708            diff_transforms,
5709            diffs: &self.diffs,
5710            cached_region: OnceCell::new(),
5711        }
5712    }
5713
5714    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5715        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5716        let mut excerpts = self
5717            .excerpts
5718            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5719        excerpts.seek(&Some(start_locator), Bias::Left);
5720        excerpts.prev();
5721
5722        let mut diff_transforms = self
5723            .diff_transforms
5724            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5725        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5726        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5727            diff_transforms.next();
5728        }
5729
5730        let excerpt = excerpts.item()?;
5731        Some(MultiBufferExcerpt {
5732            excerpt,
5733            offset: diff_transforms.start().output_dimension.0,
5734            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5735            excerpt_offset: excerpts.start().1,
5736            diff_transforms,
5737        })
5738    }
5739
5740    pub fn excerpt_boundaries_in_range<R, T>(
5741        &self,
5742        range: R,
5743    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5744    where
5745        R: RangeBounds<T>,
5746        T: ToOffset,
5747    {
5748        let start_offset;
5749        let start = match range.start_bound() {
5750            Bound::Included(start) => {
5751                start_offset = start.to_offset(self);
5752                Bound::Included(start_offset)
5753            }
5754            Bound::Excluded(_) => {
5755                panic!("not supported")
5756            }
5757            Bound::Unbounded => {
5758                start_offset = MultiBufferOffset::ZERO;
5759                Bound::Unbounded
5760            }
5761        };
5762        let end = match range.end_bound() {
5763            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5764            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5765            Bound::Unbounded => Bound::Unbounded,
5766        };
5767        let bounds = (start, end);
5768        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5769        cursor.seek(&DimensionPair {
5770            key: start_offset,
5771            value: None,
5772        });
5773
5774        if cursor
5775            .region()
5776            .is_some_and(|region| bounds.contains(&region.range.start.key))
5777        {
5778            cursor.prev_excerpt();
5779        } else {
5780            cursor.seek_to_start_of_current_excerpt();
5781        }
5782        let mut prev_region = cursor.region().cloned();
5783
5784        cursor.next_excerpt();
5785
5786        iter::from_fn(move || {
5787            loop {
5788                if self.singleton {
5789                    return None;
5790                }
5791
5792                let next_region = cursor.region()?.clone();
5793                cursor.next_excerpt();
5794                if !bounds.contains(&next_region.range.start.key) {
5795                    prev_region = Some(next_region);
5796                    continue;
5797                }
5798
5799                let next_region_start = next_region.range.start.value.unwrap();
5800                let next_region_end = if let Some(region) = cursor.region() {
5801                    region.range.start.value.unwrap()
5802                } else {
5803                    self.max_point()
5804                };
5805
5806                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5807                    id: region.excerpt.id,
5808                    buffer: region.excerpt.buffer.clone(),
5809                    buffer_id: region.excerpt.buffer_id,
5810                    range: region.excerpt.range.clone(),
5811                    end_row: MultiBufferRow(next_region_start.row),
5812                });
5813
5814                let next = ExcerptInfo {
5815                    id: next_region.excerpt.id,
5816                    buffer: next_region.excerpt.buffer.clone(),
5817                    buffer_id: next_region.excerpt.buffer_id,
5818                    range: next_region.excerpt.range.clone(),
5819                    end_row: if next_region.excerpt.has_trailing_newline {
5820                        MultiBufferRow(next_region_end.row - 1)
5821                    } else {
5822                        MultiBufferRow(next_region_end.row)
5823                    },
5824                };
5825
5826                let row = MultiBufferRow(next_region_start.row);
5827
5828                prev_region = Some(next_region);
5829
5830                return Some(ExcerptBoundary { row, prev, next });
5831            }
5832        })
5833    }
5834
5835    pub fn edit_count(&self) -> usize {
5836        self.edit_count
5837    }
5838
5839    pub fn non_text_state_update_count(&self) -> usize {
5840        self.non_text_state_update_count
5841    }
5842
5843    /// Returns the smallest enclosing bracket ranges containing the given range or
5844    /// None if no brackets contain range or the range is not contained in a single
5845    /// excerpt
5846    ///
5847    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5848    #[ztracing::instrument(skip_all)]
5849    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5850        &self,
5851        range: Range<T>,
5852        range_filter: Option<
5853            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5854        >,
5855    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5856        let range = range.start.to_offset(self)..range.end.to_offset(self);
5857        let mut excerpt = self.excerpt_containing(range.clone())?;
5858        let buffer = excerpt.buffer();
5859        let excerpt_buffer_range = excerpt.buffer_range();
5860
5861        // Filter to ranges contained in the excerpt
5862        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5863            excerpt_buffer_range.contains(&BufferOffset(open.start))
5864                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5865                && range_filter.is_none_or(|filter| {
5866                    filter(
5867                        buffer,
5868                        BufferOffset(open.start)..BufferOffset(close.end),
5869                        BufferOffset(close.start)..BufferOffset(close.end),
5870                    )
5871                })
5872        };
5873
5874        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5875            excerpt.map_range_to_buffer(range),
5876            Some(&range_filter),
5877        )?;
5878
5879        Some((
5880            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5881            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5882        ))
5883    }
5884
5885    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5886    /// not contained in a single excerpt
5887    pub fn enclosing_bracket_ranges<T: ToOffset>(
5888        &self,
5889        range: Range<T>,
5890    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5891    {
5892        let range = range.start.to_offset(self)..range.end.to_offset(self);
5893        let mut excerpt = self.excerpt_containing(range.clone())?;
5894
5895        Some(
5896            excerpt
5897                .buffer()
5898                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5899                .filter_map(move |pair| {
5900                    let open_range =
5901                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5902                    let close_range =
5903                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5904                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5905                        Some((
5906                            excerpt.map_range_from_buffer(open_range),
5907                            excerpt.map_range_from_buffer(close_range),
5908                        ))
5909                    } else {
5910                        None
5911                    }
5912                }),
5913        )
5914    }
5915
5916    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5917    /// not contained in a single excerpt
5918    pub fn text_object_ranges<T: ToOffset>(
5919        &self,
5920        range: Range<T>,
5921        options: TreeSitterOptions,
5922    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5923        let range = range.start.to_offset(self)..range.end.to_offset(self);
5924        self.excerpt_containing(range.clone())
5925            .map(|mut excerpt| {
5926                excerpt
5927                    .buffer()
5928                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5929                    .filter_map(move |(range, text_object)| {
5930                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5931                        if excerpt.contains_buffer_range(range.clone()) {
5932                            Some((excerpt.map_range_from_buffer(range), text_object))
5933                        } else {
5934                            None
5935                        }
5936                    })
5937            })
5938            .into_iter()
5939            .flatten()
5940    }
5941
5942    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5943    /// not contained in a single excerpt
5944    pub fn bracket_ranges<T: ToOffset>(
5945        &self,
5946        range: Range<T>,
5947    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5948    {
5949        let range = range.start.to_offset(self)..range.end.to_offset(self);
5950        let mut excerpt = self.excerpt_containing(range.clone())?;
5951        Some(
5952            excerpt
5953                .buffer()
5954                .bracket_ranges(excerpt.map_range_to_buffer(range))
5955                .filter_map(move |pair| {
5956                    let open_range =
5957                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5958                    let close_range =
5959                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5960                    excerpt
5961                        .contains_buffer_range(open_range.start..close_range.end)
5962                        .then(|| BracketMatch {
5963                            open_range: excerpt.map_range_from_buffer(open_range),
5964                            close_range: excerpt.map_range_from_buffer(close_range),
5965                            color_index: pair.color_index,
5966                            newline_only: pair.newline_only,
5967                            syntax_layer_depth: pair.syntax_layer_depth,
5968                        })
5969                })
5970                .map(BracketMatch::bracket_ranges),
5971        )
5972    }
5973
5974    pub fn redacted_ranges<'a, T: ToOffset>(
5975        &'a self,
5976        range: Range<T>,
5977        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5978    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5979        let range = range.start.to_offset(self)..range.end.to_offset(self);
5980        self.lift_buffer_metadata(range, move |buffer, range| {
5981            if redaction_enabled(buffer.file()) {
5982                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5983            } else {
5984                None
5985            }
5986        })
5987        .map(|(range, _, _)| range)
5988    }
5989
5990    pub fn runnable_ranges(
5991        &self,
5992        range: Range<Anchor>,
5993    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5994        let range = range.start.to_offset(self)..range.end.to_offset(self);
5995        self.lift_buffer_metadata(range, move |buffer, range| {
5996            Some(
5997                buffer
5998                    .runnable_ranges(range.clone())
5999                    .filter(move |runnable| {
6000                        runnable.run_range.start >= range.start
6001                            && runnable.run_range.end < range.end
6002                    })
6003                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6004            )
6005        })
6006        .map(|(run_range, runnable, _)| (run_range, runnable))
6007    }
6008
6009    pub fn line_indents(
6010        &self,
6011        start_row: MultiBufferRow,
6012        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6013    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6014        let max_point = self.max_point();
6015        let mut cursor = self.cursor::<Point, Point>();
6016        cursor.seek(&Point::new(start_row.0, 0));
6017        iter::from_fn(move || {
6018            let mut region = cursor.region()?;
6019            while !buffer_filter(&region.excerpt.buffer) {
6020                cursor.next();
6021                region = cursor.region()?;
6022            }
6023            let region = cursor.region()?;
6024            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6025            let buffer_start_row =
6026                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6027
6028            let buffer_end_row = if region.is_main_buffer
6029                && (region.has_trailing_newline || region.range.end == max_point)
6030            {
6031                region.buffer_range.end.row
6032            } else {
6033                region.buffer_range.end.row.saturating_sub(1)
6034            };
6035
6036            let line_indents = region
6037                .buffer
6038                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6039            let region_buffer_row = region.buffer_range.start.row;
6040            let region_row = region.range.start.row;
6041            let region_buffer = &region.excerpt.buffer;
6042            cursor.next();
6043            Some(line_indents.map(move |(buffer_row, indent)| {
6044                let row = region_row + (buffer_row - region_buffer_row);
6045                (MultiBufferRow(row), indent, region_buffer)
6046            }))
6047        })
6048        .flatten()
6049    }
6050
6051    pub fn reversed_line_indents(
6052        &self,
6053        end_row: MultiBufferRow,
6054        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6055    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6056        let max_point = self.max_point();
6057        let mut cursor = self.cursor::<Point, Point>();
6058        cursor.seek(&Point::new(end_row.0, 0));
6059        iter::from_fn(move || {
6060            let mut region = cursor.region()?;
6061            while !buffer_filter(&region.excerpt.buffer) {
6062                cursor.prev();
6063                region = cursor.region()?;
6064            }
6065            let region = cursor.region()?;
6066
6067            let buffer_start_row = region.buffer_range.start.row;
6068            let buffer_end_row = if region.is_main_buffer
6069                && (region.has_trailing_newline || region.range.end == max_point)
6070            {
6071                region.buffer_range.end.row + 1
6072            } else {
6073                region.buffer_range.end.row
6074            };
6075
6076            let overshoot = end_row.0 - region.range.start.row;
6077            let buffer_end_row =
6078                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6079
6080            let line_indents = region
6081                .buffer
6082                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6083            let region_buffer_row = region.buffer_range.start.row;
6084            let region_row = region.range.start.row;
6085            let region_buffer = &region.excerpt.buffer;
6086            cursor.prev();
6087            Some(line_indents.map(move |(buffer_row, indent)| {
6088                let row = region_row + (buffer_row - region_buffer_row);
6089                (MultiBufferRow(row), indent, region_buffer)
6090            }))
6091        })
6092        .flatten()
6093    }
6094
6095    pub async fn enclosing_indent(
6096        &self,
6097        mut target_row: MultiBufferRow,
6098    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6099        let max_row = MultiBufferRow(self.max_point().row);
6100        if target_row >= max_row {
6101            return None;
6102        }
6103
6104        let mut target_indent = self.line_indent_for_row(target_row);
6105
6106        // If the current row is at the start of an indented block, we want to return this
6107        // block as the enclosing indent.
6108        if !target_indent.is_line_empty() && target_row < max_row {
6109            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6110            if !next_line_indent.is_line_empty()
6111                && target_indent.raw_len() < next_line_indent.raw_len()
6112            {
6113                target_indent = next_line_indent;
6114                target_row.0 += 1;
6115            }
6116        }
6117
6118        const SEARCH_ROW_LIMIT: u32 = 25000;
6119        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6120        const YIELD_INTERVAL: u32 = 100;
6121
6122        let mut accessed_row_counter = 0;
6123
6124        // If there is a blank line at the current row, search for the next non indented lines
6125        if target_indent.is_line_empty() {
6126            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6127            let end =
6128                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6129
6130            let mut non_empty_line_above = None;
6131            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6132                if row < start {
6133                    break;
6134                }
6135                accessed_row_counter += 1;
6136                if accessed_row_counter == YIELD_INTERVAL {
6137                    accessed_row_counter = 0;
6138                    yield_now().await;
6139                }
6140                if !indent.is_line_empty() {
6141                    non_empty_line_above = Some((row, indent));
6142                    break;
6143                }
6144            }
6145
6146            let mut non_empty_line_below = None;
6147            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6148                if row > end {
6149                    break;
6150                }
6151                accessed_row_counter += 1;
6152                if accessed_row_counter == YIELD_INTERVAL {
6153                    accessed_row_counter = 0;
6154                    yield_now().await;
6155                }
6156                if !indent.is_line_empty() {
6157                    non_empty_line_below = Some((row, indent));
6158                    break;
6159                }
6160            }
6161
6162            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6163                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6164                    if above_indent.raw_len() >= below_indent.raw_len() {
6165                        (above_row, above_indent)
6166                    } else {
6167                        (below_row, below_indent)
6168                    }
6169                }
6170                (Some(above), None) => above,
6171                (None, Some(below)) => below,
6172                _ => return None,
6173            };
6174
6175            target_indent = indent;
6176            target_row = row;
6177        }
6178
6179        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6180        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6181
6182        let mut start_indent = None;
6183        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6184            if row < start {
6185                break;
6186            }
6187            accessed_row_counter += 1;
6188            if accessed_row_counter == YIELD_INTERVAL {
6189                accessed_row_counter = 0;
6190                yield_now().await;
6191            }
6192            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6193                start_indent = Some((row, indent));
6194                break;
6195            }
6196        }
6197        let (start_row, start_indent_size) = start_indent?;
6198
6199        let mut end_indent = (end, None);
6200        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6201            if row > end {
6202                break;
6203            }
6204            accessed_row_counter += 1;
6205            if accessed_row_counter == YIELD_INTERVAL {
6206                accessed_row_counter = 0;
6207                yield_now().await;
6208            }
6209            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6210                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6211                break;
6212            }
6213        }
6214        let (end_row, end_indent_size) = end_indent;
6215
6216        let indent = if let Some(end_indent_size) = end_indent_size {
6217            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6218                start_indent_size
6219            } else {
6220                end_indent_size
6221            }
6222        } else {
6223            start_indent_size
6224        };
6225
6226        Some((start_row..end_row, indent))
6227    }
6228
6229    pub fn indent_guides_in_range<T: ToPoint>(
6230        &self,
6231        range: Range<T>,
6232        ignore_disabled_for_language: bool,
6233        cx: &App,
6234    ) -> impl Iterator<Item = IndentGuide> {
6235        let range = range.start.to_point(self)..range.end.to_point(self);
6236        let start_row = MultiBufferRow(range.start.row);
6237        let end_row = MultiBufferRow(range.end.row);
6238
6239        let mut row_indents = self.line_indents(start_row, |buffer| {
6240            let settings =
6241                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6242            settings.indent_guides.enabled || ignore_disabled_for_language
6243        });
6244
6245        let mut result = Vec::new();
6246        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6247
6248        let mut prev_settings = None;
6249        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6250            if first_row > end_row {
6251                break;
6252            }
6253            let current_depth = indent_stack.len() as u32;
6254
6255            // Avoid retrieving the language settings repeatedly for every buffer row.
6256            if let Some((prev_buffer_id, _)) = &prev_settings
6257                && prev_buffer_id != &buffer.remote_id()
6258            {
6259                prev_settings.take();
6260            }
6261            let settings = &prev_settings
6262                .get_or_insert_with(|| {
6263                    (
6264                        buffer.remote_id(),
6265                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6266                    )
6267                })
6268                .1;
6269            let tab_size = settings.tab_size.get();
6270
6271            // When encountering empty, continue until found useful line indent
6272            // then add to the indent stack with the depth found
6273            let mut found_indent = false;
6274            let mut last_row = first_row;
6275            if line_indent.is_line_blank() {
6276                while !found_indent {
6277                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6278                        break;
6279                    };
6280                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6281                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6282                        break;
6283                    }
6284
6285                    if new_line_indent.is_line_blank() {
6286                        continue;
6287                    }
6288                    last_row = target_row.min(end_row);
6289                    line_indent = new_line_indent;
6290                    found_indent = true;
6291                    break;
6292                }
6293            } else {
6294                found_indent = true
6295            }
6296
6297            let depth = if found_indent {
6298                line_indent.len(tab_size) / tab_size
6299            } else {
6300                0
6301            };
6302
6303            match depth.cmp(&current_depth) {
6304                cmp::Ordering::Less => {
6305                    for _ in 0..(current_depth - depth) {
6306                        let mut indent = indent_stack.pop().unwrap();
6307                        if last_row != first_row {
6308                            // In this case, we landed on an empty row, had to seek forward,
6309                            // and discovered that the indent we where on is ending.
6310                            // This means that the last display row must
6311                            // be on line that ends this indent range, so we
6312                            // should display the range up to the first non-empty line
6313                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6314                        }
6315
6316                        result.push(indent)
6317                    }
6318                }
6319                cmp::Ordering::Greater => {
6320                    for next_depth in current_depth..depth {
6321                        indent_stack.push(IndentGuide {
6322                            buffer_id: buffer.remote_id(),
6323                            start_row: first_row,
6324                            end_row: last_row,
6325                            depth: next_depth,
6326                            tab_size,
6327                            settings: settings.indent_guides.clone(),
6328                        });
6329                    }
6330                }
6331                _ => {}
6332            }
6333
6334            for indent in indent_stack.iter_mut() {
6335                indent.end_row = last_row;
6336            }
6337        }
6338
6339        result.extend(indent_stack);
6340        result.into_iter()
6341    }
6342
6343    pub fn trailing_excerpt_update_count(&self) -> usize {
6344        self.trailing_excerpt_update_count
6345    }
6346
6347    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6348        self.point_to_buffer_offset(point)
6349            .and_then(|(buffer, _)| buffer.file())
6350    }
6351
6352    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6353        self.point_to_buffer_offset(offset)
6354            .and_then(|(buffer, offset)| buffer.language_at(offset))
6355    }
6356
6357    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6358        self.excerpts
6359            .first()
6360            .map(|excerpt| &excerpt.buffer)
6361            .map(|buffer| {
6362                language_settings(
6363                    buffer.language().map(|language| language.name()),
6364                    buffer.file(),
6365                    cx,
6366                )
6367            })
6368            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6369    }
6370
6371    pub fn language_settings_at<'a, T: ToOffset>(
6372        &'a self,
6373        point: T,
6374        cx: &'a App,
6375    ) -> Cow<'a, LanguageSettings> {
6376        let mut language = None;
6377        let mut file = None;
6378        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6379            language = buffer.language_at(offset);
6380            file = buffer.file();
6381        }
6382        language_settings(language.map(|l| l.name()), file, cx)
6383    }
6384
6385    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6386        self.point_to_buffer_offset(point)
6387            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6388    }
6389
6390    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6391        self.point_to_buffer_offset(point)
6392            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6393            .unwrap_or_default()
6394    }
6395
6396    pub fn language_indent_size_at<T: ToOffset>(
6397        &self,
6398        position: T,
6399        cx: &App,
6400    ) -> Option<IndentSize> {
6401        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6402        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6403    }
6404
6405    pub fn is_dirty(&self) -> bool {
6406        self.is_dirty
6407    }
6408
6409    pub fn has_deleted_file(&self) -> bool {
6410        self.has_deleted_file
6411    }
6412
6413    pub fn has_conflict(&self) -> bool {
6414        self.has_conflict
6415    }
6416
6417    pub fn has_diagnostics(&self) -> bool {
6418        self.excerpts
6419            .iter()
6420            .any(|excerpt| excerpt.buffer.has_diagnostics())
6421    }
6422
6423    pub fn diagnostic_group(
6424        &self,
6425        buffer_id: BufferId,
6426        group_id: usize,
6427    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6428        self.lift_buffer_metadata::<Point, _, _>(
6429            Point::zero()..self.max_point(),
6430            move |buffer, range| {
6431                if buffer.remote_id() != buffer_id {
6432                    return None;
6433                };
6434                Some(
6435                    buffer
6436                        .diagnostics_in_range(range, false)
6437                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6438                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6439                )
6440            },
6441        )
6442        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6443    }
6444
6445    pub fn diagnostics_in_range<'a, MBD>(
6446        &'a self,
6447        range: Range<MBD>,
6448    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6449    where
6450        MBD::TextDimension: 'a
6451            + text::ToOffset
6452            + text::FromAnchor
6453            + Sub<Output = MBD::TextDimension>
6454            + fmt::Debug
6455            + ops::Add<Output = MBD::TextDimension>
6456            + ops::AddAssign
6457            + Ord,
6458        MBD: MultiBufferDimension
6459            + Ord
6460            + Sub<Output = MBD::TextDimension>
6461            + ops::Add<MBD::TextDimension, Output = MBD>
6462            + ops::AddAssign<MBD::TextDimension>
6463            + 'a,
6464    {
6465        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6466            Some(
6467                buffer
6468                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6469                    .map(|entry| (entry.range, entry.diagnostic)),
6470            )
6471        })
6472        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6473    }
6474
6475    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6476        &'a self,
6477        range: Range<MBD>,
6478    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6479    where
6480        MBD: MultiBufferDimension
6481            + Ord
6482            + Sub<Output = MBD::TextDimension>
6483            + ops::Add<MBD::TextDimension, Output = MBD>
6484            + ops::AddAssign<MBD::TextDimension>,
6485        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6486            + ops::Add<Output = MBD::TextDimension>
6487            + text::ToOffset
6488            + text::FromAnchor
6489            + AddAssign<MBD::TextDimension>
6490            + Ord,
6491    {
6492        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6493            Some(
6494                buffer
6495                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6496                    .map(|entry| (entry.range, entry.diagnostic)),
6497            )
6498        })
6499        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6500    }
6501
6502    pub fn syntax_ancestor<T: ToOffset>(
6503        &self,
6504        range: Range<T>,
6505    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6506        let range = range.start.to_offset(self)..range.end.to_offset(self);
6507        let mut excerpt = self.excerpt_containing(range.clone())?;
6508        let node = excerpt
6509            .buffer()
6510            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6511        let node_range = node.byte_range();
6512        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6513        if !excerpt.contains_buffer_range(node_range.clone()) {
6514            return None;
6515        };
6516        Some((node, excerpt.map_range_from_buffer(node_range)))
6517    }
6518
6519    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6520        let (excerpt_id, _, buffer) = self.as_singleton()?;
6521        let outline = buffer.outline(theme);
6522        Some(Outline::new(
6523            outline
6524                .items
6525                .into_iter()
6526                .flat_map(|item| {
6527                    Some(OutlineItem {
6528                        depth: item.depth,
6529                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6530                        source_range_for_text: self
6531                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6532                        text: item.text,
6533                        highlight_ranges: item.highlight_ranges,
6534                        name_ranges: item.name_ranges,
6535                        body_range: item.body_range.and_then(|body_range| {
6536                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6537                        }),
6538                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6539                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6540                        }),
6541                    })
6542                })
6543                .collect(),
6544        ))
6545    }
6546
6547    pub fn symbols_containing<T: ToOffset>(
6548        &self,
6549        offset: T,
6550        theme: Option<&SyntaxTheme>,
6551    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6552        let anchor = self.anchor_before(offset);
6553        let excerpt @ &Excerpt {
6554            id: excerpt_id,
6555            buffer_id,
6556            ref buffer,
6557            ..
6558        } = self.excerpt(anchor.excerpt_id)?;
6559        if cfg!(debug_assertions) {
6560            match anchor.text_anchor.buffer_id {
6561                // we clearly are hitting this according to sentry, but in what situations can this occur?
6562                Some(anchor_buffer_id) => {
6563                    assert_eq!(
6564                        anchor_buffer_id, buffer_id,
6565                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6566                    )
6567                }
6568                None => assert!(anchor.is_max()),
6569            }
6570        };
6571        Some((
6572            buffer_id,
6573            buffer
6574                .symbols_containing(anchor.text_anchor, theme)
6575                .into_iter()
6576                .flat_map(|item| {
6577                    Some(OutlineItem {
6578                        depth: item.depth,
6579                        source_range_for_text: Anchor::range_in_buffer(
6580                            excerpt_id,
6581                            item.source_range_for_text,
6582                        ),
6583                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6584                        text: item.text,
6585                        highlight_ranges: item.highlight_ranges,
6586                        name_ranges: item.name_ranges,
6587                        body_range: item
6588                            .body_range
6589                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6590                        annotation_range: item
6591                            .annotation_range
6592                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6593                    })
6594                })
6595                .collect(),
6596        ))
6597    }
6598
6599    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6600        if id == ExcerptId::min() {
6601            Locator::min_ref()
6602        } else if id == ExcerptId::max() {
6603            Locator::max_ref()
6604        } else {
6605            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6606            if let Some(entry) = item
6607                && entry.id == id
6608            {
6609                return &entry.locator;
6610            }
6611            panic!("invalid excerpt id {id:?}")
6612        }
6613    }
6614
6615    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6616    fn excerpt_locators_for_ids(
6617        &self,
6618        ids: impl IntoIterator<Item = ExcerptId>,
6619    ) -> SmallVec<[Locator; 1]> {
6620        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6621        sorted_ids.sort_unstable();
6622        sorted_ids.dedup();
6623        let mut locators = SmallVec::new();
6624
6625        while sorted_ids.last() == Some(&ExcerptId::max()) {
6626            sorted_ids.pop();
6627            locators.push(Locator::max());
6628        }
6629
6630        let mut sorted_ids = sorted_ids.into_iter().peekable();
6631        locators.extend(
6632            sorted_ids
6633                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6634                .map(|_| Locator::min()),
6635        );
6636
6637        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6638        for id in sorted_ids {
6639            if cursor.seek_forward(&id, Bias::Left) {
6640                locators.push(cursor.item().unwrap().locator.clone());
6641            } else {
6642                panic!("invalid excerpt id {:?}", id);
6643            }
6644        }
6645
6646        locators.sort_unstable();
6647        locators
6648    }
6649
6650    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6651        Some(self.excerpt(excerpt_id)?.buffer_id)
6652    }
6653
6654    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6655        Some(&self.excerpt(excerpt_id)?.buffer)
6656    }
6657
6658    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6659        let mut cursor = self
6660            .excerpts
6661            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6662        let locator = self.excerpt_locator_for_id(excerpt_id);
6663        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6664        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6665            sought_exact = true;
6666            cursor.prev();
6667        } else if excerpt_id == ExcerptId::min() {
6668            sought_exact = true;
6669        }
6670        if sought_exact {
6671            let start = cursor.start().1;
6672            let end = cursor.end().1;
6673            let mut diff_transforms = self
6674                .diff_transforms
6675                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6676            diff_transforms.seek(&start, Bias::Left);
6677            let overshoot = start - diff_transforms.start().0;
6678            let start = diff_transforms.start().1 + overshoot;
6679            diff_transforms.seek(&end, Bias::Right);
6680            let overshoot = end - diff_transforms.start().0;
6681            let end = diff_transforms.start().1 + overshoot;
6682            Some(start.0..end.0)
6683        } else {
6684            None
6685        }
6686    }
6687
6688    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6689    /// to have the latest excerpt id for the one passed in and will also remap
6690    /// `ExcerptId::max()` to the corresponding excertp ID.
6691    ///
6692    /// Callers of this function should generally use the resulting excerpt's `id` field
6693    /// afterwards.
6694    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6695        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6696        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6697        let locator = self.excerpt_locator_for_id(excerpt_id);
6698        cursor.seek(&Some(locator), Bias::Left);
6699        if let Some(excerpt) = cursor.item()
6700            && excerpt.id == excerpt_id
6701        {
6702            return Some(excerpt);
6703        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6704            cursor.prev();
6705            return cursor.item();
6706        }
6707        None
6708    }
6709
6710    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6711    pub fn excerpt_containing<T: ToOffset>(
6712        &self,
6713        range: Range<T>,
6714    ) -> Option<MultiBufferExcerpt<'_>> {
6715        let range = range.start.to_offset(self)..range.end.to_offset(self);
6716        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6717        cursor.seek(&range.start);
6718
6719        let start_excerpt = cursor.excerpt()?;
6720        if range.end != range.start {
6721            cursor.seek_forward(&range.end);
6722            if cursor.excerpt()?.id != start_excerpt.id {
6723                return None;
6724            }
6725        }
6726
6727        cursor.seek_to_start_of_current_excerpt();
6728        let region = cursor.region()?;
6729        let offset = region.range.start;
6730        let buffer_offset = start_excerpt.buffer_start_offset();
6731        let excerpt_offset = *cursor.excerpts.start();
6732        Some(MultiBufferExcerpt {
6733            diff_transforms: cursor.diff_transforms,
6734            excerpt: start_excerpt,
6735            offset,
6736            buffer_offset,
6737            excerpt_offset,
6738        })
6739    }
6740
6741    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6742        if let Some(id) = anchor.text_anchor.buffer_id {
6743            return Some(id);
6744        }
6745        let excerpt = self.excerpt_containing(anchor..anchor)?;
6746        Some(excerpt.buffer_id())
6747    }
6748
6749    pub fn selections_in_range<'a>(
6750        &'a self,
6751        range: &'a Range<Anchor>,
6752        include_local: bool,
6753    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6754        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6755        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6756        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6757        cursor.seek(start_locator, Bias::Left);
6758        cursor
6759            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6760            .flat_map(move |excerpt| {
6761                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6762                if excerpt.id == range.start.excerpt_id {
6763                    query_range.start = range.start.text_anchor;
6764                }
6765                if excerpt.id == range.end.excerpt_id {
6766                    query_range.end = range.end.text_anchor;
6767                }
6768
6769                excerpt
6770                    .buffer
6771                    .selections_in_range(query_range, include_local)
6772                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6773                        selections.map(move |selection| {
6774                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6775                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6776                            if range.start.cmp(&start, self).is_gt() {
6777                                start = range.start;
6778                            }
6779                            if range.end.cmp(&end, self).is_lt() {
6780                                end = range.end;
6781                            }
6782
6783                            (
6784                                replica_id,
6785                                line_mode,
6786                                cursor_shape,
6787                                Selection {
6788                                    id: selection.id,
6789                                    start,
6790                                    end,
6791                                    reversed: selection.reversed,
6792                                    goal: selection.goal,
6793                                },
6794                            )
6795                        })
6796                    })
6797            })
6798    }
6799
6800    pub fn show_headers(&self) -> bool {
6801        self.show_headers
6802    }
6803
6804    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6805        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6806    }
6807
6808    pub fn all_diff_hunks_expanded(&self) -> bool {
6809        self.all_diff_hunks_expanded
6810    }
6811
6812    /// Visually annotates a position or range with the `Debug` representation of a value. The
6813    /// callsite of this function is used as a key - previous annotations will be removed.
6814    #[cfg(debug_assertions)]
6815    #[track_caller]
6816    pub fn debug<V, R>(&self, ranges: &R, value: V)
6817    where
6818        R: debug::ToMultiBufferDebugRanges,
6819        V: std::fmt::Debug,
6820    {
6821        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6822    }
6823
6824    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6825    /// debug annotations with the same key will be removed. The key is also used to determine the
6826    /// annotation's color.
6827    #[cfg(debug_assertions)]
6828    #[track_caller]
6829    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6830    where
6831        K: std::hash::Hash + 'static,
6832        R: debug::ToMultiBufferDebugRanges,
6833        V: std::fmt::Debug,
6834    {
6835        let text_ranges = ranges
6836            .to_multi_buffer_debug_ranges(self)
6837            .into_iter()
6838            .flat_map(|range| {
6839                self.range_to_buffer_ranges(range.start..=range.end)
6840                    .into_iter()
6841                    .map(|(buffer, range, _excerpt_id)| {
6842                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6843                    })
6844            })
6845            .collect();
6846        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6847            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6848        });
6849    }
6850
6851    fn excerpt_edits_for_diff_change(
6852        &self,
6853        buffer_state: &BufferState,
6854        diff_change_range: Range<usize>,
6855    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6856        let mut excerpt_edits = Vec::new();
6857        for locator in &buffer_state.excerpts {
6858            let mut cursor = self
6859                .excerpts
6860                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6861            cursor.seek_forward(&Some(locator), Bias::Left);
6862            if let Some(excerpt) = cursor.item()
6863                && excerpt.locator == *locator
6864            {
6865                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6866                if diff_change_range.end < excerpt_buffer_range.start
6867                    || diff_change_range.start > excerpt_buffer_range.end
6868                {
6869                    continue;
6870                }
6871                let excerpt_start = cursor.start().1;
6872                let excerpt_len = excerpt.text_summary.len;
6873                let diff_change_start_in_excerpt = diff_change_range
6874                    .start
6875                    .saturating_sub(excerpt_buffer_range.start);
6876                let diff_change_end_in_excerpt = diff_change_range
6877                    .end
6878                    .saturating_sub(excerpt_buffer_range.start);
6879                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6880                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6881                excerpt_edits.push(Edit {
6882                    old: edit_start..edit_end,
6883                    new: edit_start..edit_end,
6884                });
6885            }
6886        }
6887        excerpt_edits
6888    }
6889}
6890
6891#[cfg(any(test, feature = "test-support"))]
6892impl MultiBufferSnapshot {
6893    pub fn random_byte_range(
6894        &self,
6895        start_offset: MultiBufferOffset,
6896        rng: &mut impl rand::Rng,
6897    ) -> Range<MultiBufferOffset> {
6898        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6899        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6900        start..end
6901    }
6902
6903    #[cfg(any(test, feature = "test-support"))]
6904    fn check_invariants(&self) {
6905        let excerpts = self.excerpts.items(());
6906        let excerpt_ids = self.excerpt_ids.items(());
6907
6908        for (ix, excerpt) in excerpts.iter().enumerate() {
6909            if ix == 0 {
6910                if excerpt.locator <= Locator::min() {
6911                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6912                }
6913            } else if excerpt.locator <= excerpts[ix - 1].locator {
6914                panic!("excerpts are out-of-order: {:?}", excerpts);
6915            }
6916        }
6917
6918        for (ix, entry) in excerpt_ids.iter().enumerate() {
6919            if ix == 0 {
6920                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6921                    panic!("invalid first excerpt id {:?}", entry.id);
6922                }
6923            } else if entry.id <= excerpt_ids[ix - 1].id {
6924                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6925            }
6926        }
6927
6928        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6929            panic!(
6930                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6931                self.excerpts.summary().text,
6932                self.diff_transforms.summary().input,
6933                self.diff_transforms.items(()),
6934            );
6935        }
6936
6937        let mut prev_transform: Option<&DiffTransform> = None;
6938        for item in self.diff_transforms.iter() {
6939            if let DiffTransform::BufferContent {
6940                summary,
6941                inserted_hunk_info,
6942            } = item
6943            {
6944                if let Some(DiffTransform::BufferContent {
6945                    inserted_hunk_info: prev_inserted_hunk_info,
6946                    ..
6947                }) = prev_transform
6948                    && *inserted_hunk_info == *prev_inserted_hunk_info
6949                {
6950                    panic!(
6951                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6952                        self.diff_transforms.items(())
6953                    );
6954                }
6955                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6956                    panic!("empty buffer content transform");
6957                }
6958            }
6959            prev_transform = Some(item);
6960        }
6961    }
6962}
6963
6964impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6965where
6966    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6967    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6968{
6969    #[instrument(skip_all)]
6970    fn seek(&mut self, position: &MBD) {
6971        let position = OutputDimension(*position);
6972        self.cached_region.take();
6973        self.diff_transforms.seek(&position, Bias::Right);
6974        if self.diff_transforms.item().is_none()
6975            && self.diff_transforms.start().output_dimension == position
6976        {
6977            self.diff_transforms.prev();
6978        }
6979
6980        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6981        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6982            let overshoot = position - self.diff_transforms.start().output_dimension;
6983            excerpt_position += overshoot;
6984        }
6985
6986        self.excerpts.seek(&excerpt_position, Bias::Right);
6987        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6988            self.excerpts.prev();
6989        }
6990    }
6991
6992    fn seek_forward(&mut self, position: &MBD) {
6993        let position = OutputDimension(*position);
6994        self.cached_region.take();
6995        self.diff_transforms.seek_forward(&position, Bias::Right);
6996        if self.diff_transforms.item().is_none()
6997            && self.diff_transforms.start().output_dimension == position
6998        {
6999            self.diff_transforms.prev();
7000        }
7001
7002        let overshoot = position - self.diff_transforms.start().output_dimension;
7003        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7004        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7005            excerpt_position += overshoot;
7006        }
7007
7008        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7009        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7010            self.excerpts.prev();
7011        }
7012    }
7013
7014    fn next_excerpt(&mut self) {
7015        self.excerpts.next();
7016        self.seek_to_start_of_current_excerpt();
7017    }
7018
7019    fn prev_excerpt(&mut self) {
7020        self.excerpts.prev();
7021        self.seek_to_start_of_current_excerpt();
7022    }
7023
7024    fn seek_to_start_of_current_excerpt(&mut self) {
7025        self.cached_region.take();
7026        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
7027        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
7028            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7029            && self.diff_transforms.next_item().is_some()
7030        {
7031            self.diff_transforms.next();
7032        }
7033    }
7034
7035    fn next(&mut self) {
7036        self.cached_region.take();
7037        match self
7038            .diff_transforms
7039            .end()
7040            .excerpt_dimension
7041            .cmp(&self.excerpts.end())
7042        {
7043            cmp::Ordering::Less => self.diff_transforms.next(),
7044            cmp::Ordering::Greater => self.excerpts.next(),
7045            cmp::Ordering::Equal => {
7046                self.diff_transforms.next();
7047                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7048                    || self.diff_transforms.item().is_none()
7049                {
7050                    self.excerpts.next();
7051                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7052                    self.diff_transforms.item()
7053                    && self
7054                        .excerpts
7055                        .item()
7056                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7057                {
7058                    self.excerpts.next();
7059                }
7060            }
7061        }
7062    }
7063
7064    fn prev(&mut self) {
7065        self.cached_region.take();
7066        match self
7067            .diff_transforms
7068            .start()
7069            .excerpt_dimension
7070            .cmp(self.excerpts.start())
7071        {
7072            cmp::Ordering::Less => self.excerpts.prev(),
7073            cmp::Ordering::Greater => self.diff_transforms.prev(),
7074            cmp::Ordering::Equal => {
7075                self.diff_transforms.prev();
7076                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7077                    || self.diff_transforms.item().is_none()
7078                {
7079                    self.excerpts.prev();
7080                }
7081            }
7082        }
7083    }
7084
7085    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7086        self.cached_region
7087            .get_or_init(|| self.build_region())
7088            .as_ref()
7089    }
7090
7091    fn is_at_start_of_excerpt(&mut self) -> bool {
7092        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7093            return false;
7094        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7095            return true;
7096        }
7097
7098        self.diff_transforms.prev();
7099        let prev_transform = self.diff_transforms.item();
7100        self.diff_transforms.next();
7101
7102        prev_transform.is_none_or(|next_transform| {
7103            matches!(next_transform, DiffTransform::BufferContent { .. })
7104        })
7105    }
7106
7107    fn is_at_end_of_excerpt(&self) -> bool {
7108        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7109            return false;
7110        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7111            || self.diff_transforms.item().is_none()
7112        {
7113            return true;
7114        }
7115
7116        let next_transform = self.diff_transforms.next_item();
7117        next_transform.is_none_or(|next_transform| match next_transform {
7118            DiffTransform::BufferContent { .. } => true,
7119            DiffTransform::DeletedHunk { hunk_info, .. } => self
7120                .excerpts
7121                .item()
7122                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7123        })
7124    }
7125
7126    fn main_buffer_position(&self) -> Option<BD> {
7127        let excerpt = self.excerpts.item()?;
7128        let buffer = &excerpt.buffer;
7129        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7130        let mut buffer_start = buffer_context_start;
7131        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7132        buffer_start += overshoot;
7133        Some(buffer_start)
7134    }
7135
7136    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7137        let excerpt = self.excerpts.item()?;
7138        match self.diff_transforms.item()? {
7139            DiffTransform::DeletedHunk {
7140                buffer_id,
7141                base_text_byte_range,
7142                has_trailing_newline,
7143                hunk_info,
7144                ..
7145            } => {
7146                let diff = self.diffs.get(buffer_id)?;
7147                let buffer = diff.base_text();
7148                let mut rope_cursor = buffer.as_rope().cursor(0);
7149                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7150                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7151                let mut buffer_end = buffer_start;
7152                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7153                let start = self.diff_transforms.start().output_dimension.0;
7154                let end = self.diff_transforms.end().output_dimension.0;
7155                Some(MultiBufferRegion {
7156                    buffer,
7157                    excerpt,
7158                    has_trailing_newline: *has_trailing_newline,
7159                    is_main_buffer: false,
7160                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7161                        hunk_info.hunk_secondary_status,
7162                    )),
7163                    buffer_range: buffer_start..buffer_end,
7164                    range: start..end,
7165                })
7166            }
7167            DiffTransform::BufferContent {
7168                inserted_hunk_info, ..
7169            } => {
7170                let buffer = &excerpt.buffer;
7171                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7172
7173                let mut start = self.diff_transforms.start().output_dimension.0;
7174                let mut buffer_start = buffer_context_start;
7175                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7176                    let overshoot =
7177                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7178                    start += overshoot;
7179                } else {
7180                    let overshoot =
7181                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7182                    buffer_start += overshoot;
7183                }
7184
7185                let mut end;
7186                let mut buffer_end;
7187                let has_trailing_newline;
7188                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7189                    let overshoot =
7190                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7191                    end = self.diff_transforms.end().output_dimension.0;
7192                    buffer_end = buffer_context_start;
7193                    buffer_end += overshoot;
7194                    has_trailing_newline = false;
7195                } else {
7196                    let overshoot =
7197                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7198                    end = self.diff_transforms.start().output_dimension.0;
7199                    end += overshoot;
7200                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7201                    has_trailing_newline = excerpt.has_trailing_newline;
7202                };
7203
7204                let diff_hunk_status = inserted_hunk_info.map(|info| {
7205                    if info.is_logically_deleted {
7206                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7207                    } else {
7208                        DiffHunkStatus::added(info.hunk_secondary_status)
7209                    }
7210                });
7211
7212                Some(MultiBufferRegion {
7213                    buffer,
7214                    excerpt,
7215                    has_trailing_newline,
7216                    is_main_buffer: true,
7217                    diff_hunk_status,
7218                    buffer_range: buffer_start..buffer_end,
7219                    range: start..end,
7220                })
7221            }
7222        }
7223    }
7224
7225    fn excerpt(&self) -> Option<&'a Excerpt> {
7226        self.excerpts.item()
7227    }
7228}
7229
7230impl Excerpt {
7231    fn new(
7232        id: ExcerptId,
7233        locator: Locator,
7234        buffer_id: BufferId,
7235        buffer: BufferSnapshot,
7236        range: ExcerptRange<text::Anchor>,
7237        has_trailing_newline: bool,
7238    ) -> Self {
7239        Excerpt {
7240            id,
7241            locator,
7242            max_buffer_row: range.context.end.to_point(&buffer).row,
7243            text_summary: buffer
7244                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7245            buffer_id,
7246            buffer,
7247            range,
7248            has_trailing_newline,
7249        }
7250    }
7251
7252    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7253        let content_start = self.range.context.start.to_offset(&self.buffer);
7254        let chunks_start = content_start + range.start;
7255        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7256
7257        let has_footer = self.has_trailing_newline
7258            && range.start <= self.text_summary.len
7259            && range.end > self.text_summary.len;
7260
7261        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7262
7263        ExcerptChunks {
7264            excerpt_id: self.id,
7265            content_chunks,
7266            has_footer,
7267        }
7268    }
7269
7270    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7271        let content_start = self.range.context.start.to_offset(&self.buffer);
7272        let chunks_start = content_start + range.start;
7273        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7274        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7275        excerpt_chunks.has_footer = self.has_trailing_newline
7276            && range.start <= self.text_summary.len
7277            && range.end > self.text_summary.len;
7278    }
7279
7280    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7281        if text_anchor
7282            .cmp(&self.range.context.start, &self.buffer)
7283            .is_lt()
7284        {
7285            self.range.context.start
7286        } else if text_anchor
7287            .cmp(&self.range.context.end, &self.buffer)
7288            .is_gt()
7289        {
7290            self.range.context.end
7291        } else {
7292            text_anchor
7293        }
7294    }
7295
7296    fn contains(&self, anchor: &Anchor) -> bool {
7297        (anchor.text_anchor.buffer_id == None
7298            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7299            && self
7300                .range
7301                .context
7302                .start
7303                .cmp(&anchor.text_anchor, &self.buffer)
7304                .is_le()
7305            && self
7306                .range
7307                .context
7308                .end
7309                .cmp(&anchor.text_anchor, &self.buffer)
7310                .is_ge()
7311    }
7312
7313    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7314    fn buffer_start_offset(&self) -> BufferOffset {
7315        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7316    }
7317
7318    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7319    fn buffer_end_offset(&self) -> BufferOffset {
7320        self.buffer_start_offset() + self.text_summary.len
7321    }
7322}
7323
7324impl<'a> MultiBufferExcerpt<'a> {
7325    pub fn id(&self) -> ExcerptId {
7326        self.excerpt.id
7327    }
7328
7329    pub fn buffer_id(&self) -> BufferId {
7330        self.excerpt.buffer_id
7331    }
7332
7333    pub fn start_anchor(&self) -> Anchor {
7334        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7335    }
7336
7337    pub fn end_anchor(&self) -> Anchor {
7338        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7339    }
7340
7341    pub fn buffer(&self) -> &'a BufferSnapshot {
7342        &self.excerpt.buffer
7343    }
7344
7345    pub fn buffer_range(&self) -> Range<BufferOffset> {
7346        self.buffer_offset
7347            ..BufferOffset(
7348                self.excerpt
7349                    .range
7350                    .context
7351                    .end
7352                    .to_offset(&self.excerpt.buffer.text),
7353            )
7354    }
7355
7356    pub fn start_offset(&self) -> MultiBufferOffset {
7357        self.offset
7358    }
7359
7360    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7361    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7362        self.map_range_to_buffer(offset..offset).start
7363    }
7364
7365    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7366    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7367        self.diff_transforms
7368            .seek(&OutputDimension(range.start), Bias::Right);
7369        let start = self.map_offset_to_buffer_internal(range.start);
7370        let end = if range.end > range.start {
7371            self.diff_transforms
7372                .seek_forward(&OutputDimension(range.end), Bias::Right);
7373            self.map_offset_to_buffer_internal(range.end)
7374        } else {
7375            start
7376        };
7377        start..end
7378    }
7379
7380    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7381        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7382        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7383            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7384        };
7385        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7386        self.buffer_offset + offset_in_excerpt
7387    }
7388
7389    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7390    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7391        self.map_range_from_buffer(buffer_offset..buffer_offset)
7392            .start
7393    }
7394
7395    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7396    pub fn map_range_from_buffer(
7397        &mut self,
7398        buffer_range: Range<BufferOffset>,
7399    ) -> Range<MultiBufferOffset> {
7400        if buffer_range.start < self.buffer_offset {
7401            log::warn!(
7402                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7403            );
7404            return self.offset..self.offset;
7405        }
7406        let overshoot = buffer_range.start - self.buffer_offset;
7407        let excerpt_offset = self.excerpt_offset + overshoot;
7408        let excerpt_seek_dim = excerpt_offset;
7409        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7410        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7411            log::warn!(
7412                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7413            );
7414            return self.offset..self.offset;
7415        }
7416        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7417        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7418
7419        let end = if buffer_range.start < buffer_range.end {
7420            let overshoot = buffer_range.end - self.buffer_offset;
7421            let excerpt_offset = self.excerpt_offset + overshoot;
7422            let excerpt_seek_dim = excerpt_offset;
7423            self.diff_transforms
7424                .seek_forward(&excerpt_seek_dim, Bias::Right);
7425            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7426            // todo(lw): Clamp end to the excerpt boundaries
7427            self.diff_transforms.start().output_dimension.0 + overshoot
7428        } else {
7429            start
7430        };
7431
7432        start..end
7433    }
7434
7435    /// Returns true if the entirety of the given range is in the buffer's excerpt
7436    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7437        range.start >= self.excerpt.buffer_start_offset()
7438            && range.end <= self.excerpt.buffer_end_offset()
7439    }
7440
7441    /// Returns true if any part of the given range is in the buffer's excerpt
7442    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7443        range.start <= self.excerpt.buffer_end_offset()
7444            && range.end >= self.excerpt.buffer_start_offset()
7445    }
7446
7447    pub fn max_buffer_row(&self) -> u32 {
7448        self.excerpt.max_buffer_row
7449    }
7450}
7451
7452impl ExcerptId {
7453    pub fn min() -> Self {
7454        Self(0)
7455    }
7456
7457    pub fn max() -> Self {
7458        Self(u32::MAX)
7459    }
7460
7461    pub fn to_proto(self) -> u64 {
7462        self.0 as _
7463    }
7464
7465    pub fn from_proto(proto: u64) -> Self {
7466        Self(proto as _)
7467    }
7468
7469    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7470        let a = snapshot.excerpt_locator_for_id(*self);
7471        let b = snapshot.excerpt_locator_for_id(*other);
7472        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7473    }
7474}
7475
7476impl From<ExcerptId> for usize {
7477    fn from(val: ExcerptId) -> Self {
7478        val.0 as usize
7479    }
7480}
7481
7482impl fmt::Debug for Excerpt {
7483    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7484        f.debug_struct("Excerpt")
7485            .field("id", &self.id)
7486            .field("locator", &self.locator)
7487            .field("buffer_id", &self.buffer_id)
7488            .field("range", &self.range)
7489            .field("text_summary", &self.text_summary)
7490            .field("has_trailing_newline", &self.has_trailing_newline)
7491            .finish()
7492    }
7493}
7494
7495impl sum_tree::Item for Excerpt {
7496    type Summary = ExcerptSummary;
7497
7498    fn summary(&self, _cx: ()) -> Self::Summary {
7499        let mut text = self.text_summary;
7500        if self.has_trailing_newline {
7501            text += TextSummary::from("\n");
7502        }
7503        ExcerptSummary {
7504            excerpt_id: self.id,
7505            excerpt_locator: self.locator.clone(),
7506            widest_line_number: self.max_buffer_row,
7507            text: text.into(),
7508        }
7509    }
7510}
7511
7512impl sum_tree::Item for ExcerptIdMapping {
7513    type Summary = ExcerptId;
7514
7515    fn summary(&self, _cx: ()) -> Self::Summary {
7516        self.id
7517    }
7518}
7519
7520impl sum_tree::KeyedItem for ExcerptIdMapping {
7521    type Key = ExcerptId;
7522
7523    fn key(&self) -> Self::Key {
7524        self.id
7525    }
7526}
7527
7528impl DiffTransform {
7529    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7530        match self {
7531            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7532            DiffTransform::BufferContent {
7533                inserted_hunk_info, ..
7534            } => *inserted_hunk_info,
7535        }
7536    }
7537}
7538
7539impl sum_tree::Item for DiffTransform {
7540    type Summary = DiffTransformSummary;
7541
7542    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7543        match self {
7544            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7545                input: *summary,
7546                output: *summary,
7547            },
7548            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7549                input: MBTextSummary::default(),
7550                output: summary.into(),
7551            },
7552        }
7553    }
7554}
7555
7556impl DiffTransformSummary {
7557    fn excerpt_len(&self) -> ExcerptOffset {
7558        ExcerptDimension(self.input.len)
7559    }
7560}
7561
7562impl sum_tree::ContextLessSummary for DiffTransformSummary {
7563    fn zero() -> Self {
7564        DiffTransformSummary {
7565            input: MBTextSummary::default(),
7566            output: MBTextSummary::default(),
7567        }
7568    }
7569
7570    fn add_summary(&mut self, other: &Self) {
7571        self.input += other.input;
7572        self.output += other.output;
7573    }
7574}
7575
7576impl sum_tree::ContextLessSummary for ExcerptId {
7577    fn zero() -> Self {
7578        Self(0)
7579    }
7580
7581    fn add_summary(&mut self, summary: &Self) {
7582        *self = cmp::max(*self, *summary);
7583    }
7584}
7585
7586impl sum_tree::ContextLessSummary for ExcerptSummary {
7587    fn zero() -> Self {
7588        Self::default()
7589    }
7590
7591    fn add_summary(&mut self, summary: &Self) {
7592        debug_assert!(
7593            summary.excerpt_locator > self.excerpt_locator
7594                || self.excerpt_locator == Locator::min(),
7595            "Excerpt locators must be in ascending order: {:?} > {:?}",
7596            summary.excerpt_locator,
7597            self.excerpt_locator
7598        );
7599        self.excerpt_locator = summary.excerpt_locator.clone();
7600        self.text += summary.text;
7601        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7602    }
7603}
7604
7605impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7606    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7607        Ord::cmp(&Some(self), cursor_location)
7608    }
7609}
7610
7611impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7612    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7613        Ord::cmp(self, &cursor_location.excerpt_locator)
7614    }
7615}
7616
7617impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7618where
7619    MBD: MultiBufferDimension + Default,
7620{
7621    fn zero(_: ()) -> Self {
7622        ExcerptDimension(MBD::default())
7623    }
7624
7625    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7626        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7627    }
7628}
7629
7630impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7631    fn zero(_cx: ()) -> Self {
7632        Default::default()
7633    }
7634
7635    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7636        *self = Some(&summary.excerpt_locator);
7637    }
7638}
7639
7640impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7641    fn zero(_cx: ()) -> Self {
7642        Default::default()
7643    }
7644
7645    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7646        *self = Some(summary.excerpt_id);
7647    }
7648}
7649
7650#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7651struct OutputDimension<T>(T);
7652
7653impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7654    fn eq(&self, other: &T) -> bool {
7655        self.0 == *other
7656    }
7657}
7658
7659impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7660    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7661        self.0.partial_cmp(other)
7662    }
7663}
7664
7665impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7666where
7667    T: ops::Sub<U, Output = R>,
7668{
7669    type Output = R;
7670
7671    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7672        self.0 - other.0
7673    }
7674}
7675
7676impl<R, T, U> ops::Add<U> for OutputDimension<T>
7677where
7678    T: ops::Add<U, Output = R>,
7679{
7680    type Output = OutputDimension<R>;
7681
7682    fn add(self, other: U) -> Self::Output {
7683        OutputDimension(self.0 + other)
7684    }
7685}
7686
7687impl<T, U> AddAssign<U> for OutputDimension<T>
7688where
7689    T: AddAssign<U>,
7690{
7691    fn add_assign(&mut self, other: U) {
7692        self.0 += other;
7693    }
7694}
7695
7696impl<T, U> SubAssign<U> for OutputDimension<T>
7697where
7698    T: SubAssign<U>,
7699{
7700    fn sub_assign(&mut self, other: U) {
7701        self.0 -= other;
7702    }
7703}
7704
7705#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7706struct ExcerptDimension<T>(T);
7707
7708impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7709    fn eq(&self, other: &T) -> bool {
7710        self.0 == *other
7711    }
7712}
7713
7714impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7715    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7716        self.0.partial_cmp(other)
7717    }
7718}
7719
7720impl ExcerptOffset {
7721    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7722        self.0.saturating_sub(other.0)
7723    }
7724}
7725
7726impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7727where
7728    T: ops::Sub<U, Output = R>,
7729{
7730    type Output = R;
7731
7732    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7733        self.0 - other.0
7734    }
7735}
7736
7737impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7738where
7739    T: ops::Add<U, Output = R>,
7740{
7741    type Output = ExcerptDimension<R>;
7742
7743    fn add(self, other: U) -> Self::Output {
7744        ExcerptDimension(self.0 + other)
7745    }
7746}
7747
7748impl<T, U> AddAssign<U> for ExcerptDimension<T>
7749where
7750    T: AddAssign<U>,
7751{
7752    fn add_assign(&mut self, other: U) {
7753        self.0 += other;
7754    }
7755}
7756
7757impl<T, U> SubAssign<U> for ExcerptDimension<T>
7758where
7759    T: SubAssign<U>,
7760{
7761    fn sub_assign(&mut self, other: U) {
7762        self.0 -= other;
7763    }
7764}
7765
7766impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7767    fn zero(_: ()) -> Self {
7768        MultiBufferOffset::ZERO
7769    }
7770
7771    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7772        *self += summary.output.len;
7773    }
7774}
7775
7776impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7777    for ExcerptDimension<MBD>
7778where
7779    MBD: MultiBufferDimension + Ord,
7780{
7781    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7782        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7783    }
7784}
7785
7786impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7787    for ExcerptDimension<MBD>
7788where
7789    MBD: MultiBufferDimension + Ord,
7790{
7791    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7792        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7793    }
7794}
7795
7796impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7797    for ExcerptDimension<MBD>
7798{
7799    fn zero(_: ()) -> Self {
7800        ExcerptDimension(MBD::default())
7801    }
7802
7803    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7804        self.0.add_mb_text_summary(&summary.input)
7805    }
7806}
7807
7808impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7809    for OutputDimension<MBD>
7810where
7811    MBD: MultiBufferDimension + Ord,
7812{
7813    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7814        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7815    }
7816}
7817
7818impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7819    for OutputDimension<MBD>
7820{
7821    fn zero(_: ()) -> Self {
7822        OutputDimension(MBD::default())
7823    }
7824
7825    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7826        self.0.add_mb_text_summary(&summary.output)
7827    }
7828}
7829
7830impl MultiBufferRows<'_> {
7831    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7832        self.point = Point::new(row, 0);
7833        self.cursor.seek(&self.point);
7834    }
7835}
7836
7837impl Iterator for MultiBufferRows<'_> {
7838    type Item = RowInfo;
7839
7840    fn next(&mut self) -> Option<Self::Item> {
7841        if self.is_empty && self.point.row == 0 {
7842            self.point += Point::new(1, 0);
7843            return Some(RowInfo {
7844                buffer_id: None,
7845                buffer_row: Some(0),
7846                multibuffer_row: Some(MultiBufferRow(0)),
7847                diff_status: None,
7848                expand_info: None,
7849                wrapped_buffer_row: None,
7850            });
7851        }
7852
7853        let mut region = self.cursor.region()?.clone();
7854        while self.point >= region.range.end {
7855            self.cursor.next();
7856            if let Some(next_region) = self.cursor.region() {
7857                region = next_region.clone();
7858            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7859                let multibuffer_row = MultiBufferRow(self.point.row);
7860                let last_excerpt = self
7861                    .cursor
7862                    .excerpts
7863                    .item()
7864                    .or(self.cursor.excerpts.prev_item())?;
7865                let last_row = last_excerpt
7866                    .range
7867                    .context
7868                    .end
7869                    .to_point(&last_excerpt.buffer)
7870                    .row;
7871
7872                let first_row = last_excerpt
7873                    .range
7874                    .context
7875                    .start
7876                    .to_point(&last_excerpt.buffer)
7877                    .row;
7878
7879                let expand_info = if self.is_singleton {
7880                    None
7881                } else {
7882                    let needs_expand_up = first_row == last_row
7883                        && last_row > 0
7884                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7885                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7886
7887                    if needs_expand_up && needs_expand_down {
7888                        Some(ExpandExcerptDirection::UpAndDown)
7889                    } else if needs_expand_up {
7890                        Some(ExpandExcerptDirection::Up)
7891                    } else if needs_expand_down {
7892                        Some(ExpandExcerptDirection::Down)
7893                    } else {
7894                        None
7895                    }
7896                    .map(|direction| ExpandInfo {
7897                        direction,
7898                        excerpt_id: last_excerpt.id,
7899                    })
7900                };
7901                self.point += Point::new(1, 0);
7902                return Some(RowInfo {
7903                    buffer_id: Some(last_excerpt.buffer_id),
7904                    buffer_row: Some(last_row),
7905                    multibuffer_row: Some(multibuffer_row),
7906                    diff_status: None,
7907                    wrapped_buffer_row: None,
7908                    expand_info,
7909                });
7910            } else {
7911                return None;
7912            };
7913        }
7914
7915        let overshoot = self.point - region.range.start;
7916        let buffer_point = region.buffer_range.start + overshoot;
7917        let expand_info = if self.is_singleton {
7918            None
7919        } else {
7920            let needs_expand_up = self.point.row == region.range.start.row
7921                && self.cursor.is_at_start_of_excerpt()
7922                && buffer_point.row > 0;
7923            let needs_expand_down = (region.excerpt.has_trailing_newline
7924                && self.point.row + 1 == region.range.end.row
7925                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7926                && self.cursor.is_at_end_of_excerpt()
7927                && buffer_point.row < region.buffer.max_point().row;
7928
7929            if needs_expand_up && needs_expand_down {
7930                Some(ExpandExcerptDirection::UpAndDown)
7931            } else if needs_expand_up {
7932                Some(ExpandExcerptDirection::Up)
7933            } else if needs_expand_down {
7934                Some(ExpandExcerptDirection::Down)
7935            } else {
7936                None
7937            }
7938            .map(|direction| ExpandInfo {
7939                direction,
7940                excerpt_id: region.excerpt.id,
7941            })
7942        };
7943
7944        let result = Some(RowInfo {
7945            buffer_id: Some(region.buffer.remote_id()),
7946            buffer_row: Some(buffer_point.row),
7947            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7948            diff_status: region
7949                .diff_hunk_status
7950                .filter(|_| self.point < region.range.end),
7951            expand_info,
7952            wrapped_buffer_row: None,
7953        });
7954        self.point += Point::new(1, 0);
7955        result
7956    }
7957}
7958
7959impl<'a> MultiBufferChunks<'a> {
7960    pub fn offset(&self) -> MultiBufferOffset {
7961        self.range.start
7962    }
7963
7964    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7965        self.diff_transforms.seek(&range.end, Bias::Right);
7966        let mut excerpt_end = self.diff_transforms.start().1;
7967        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7968            let overshoot = range.end - self.diff_transforms.start().0;
7969            excerpt_end += overshoot;
7970        }
7971
7972        self.diff_transforms.seek(&range.start, Bias::Right);
7973        let mut excerpt_start = self.diff_transforms.start().1;
7974        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7975            let overshoot = range.start - self.diff_transforms.start().0;
7976            excerpt_start += overshoot;
7977        }
7978
7979        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7980        self.buffer_chunk.take();
7981        self.range = range;
7982    }
7983
7984    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7985        self.excerpt_offset_range = new_range.clone();
7986        self.excerpts.seek(&new_range.start, Bias::Right);
7987        if let Some(excerpt) = self.excerpts.item() {
7988            let excerpt_start = *self.excerpts.start();
7989            if let Some(excerpt_chunks) = self
7990                .excerpt_chunks
7991                .as_mut()
7992                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7993            {
7994                excerpt.seek_chunks(
7995                    excerpt_chunks,
7996                    (self.excerpt_offset_range.start - excerpt_start)
7997                        ..(self.excerpt_offset_range.end - excerpt_start),
7998                );
7999            } else {
8000                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8001                    (self.excerpt_offset_range.start - excerpt_start)
8002                        ..(self.excerpt_offset_range.end - excerpt_start),
8003                    self.language_aware,
8004                ));
8005            }
8006        } else {
8007            self.excerpt_chunks = None;
8008        }
8009    }
8010
8011    #[ztracing::instrument(skip_all)]
8012    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8013        loop {
8014            if self.excerpt_offset_range.is_empty() {
8015                return None;
8016            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8017                self.excerpt_offset_range.start += chunk.text.len();
8018                return Some(chunk);
8019            } else {
8020                self.excerpts.next();
8021                let excerpt = self.excerpts.item()?;
8022                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8023                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8024                    self.language_aware,
8025                ));
8026            }
8027        }
8028    }
8029}
8030
8031impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8032    type Item = &'a str;
8033
8034    fn next(&mut self) -> Option<Self::Item> {
8035        let mut region = self.cursor.region()?;
8036        if self.offset == region.range.start {
8037            self.cursor.prev();
8038            region = self.cursor.region()?;
8039            let start_overshoot = self.start.saturating_sub(region.range.start);
8040            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8041                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8042            ));
8043        }
8044
8045        if self.offset == region.range.end && region.has_trailing_newline {
8046            self.offset -= 1;
8047            Some("\n")
8048        } else {
8049            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8050            self.offset -= chunk.len();
8051            Some(chunk)
8052        }
8053    }
8054}
8055
8056impl<'a> Iterator for MultiBufferChunks<'a> {
8057    type Item = Chunk<'a>;
8058
8059    #[ztracing::instrument(skip_all)]
8060    fn next(&mut self) -> Option<Chunk<'a>> {
8061        if self.range.start >= self.range.end {
8062            return None;
8063        }
8064        if self.range.start == self.diff_transforms.end().0 {
8065            self.diff_transforms.next();
8066        }
8067
8068        let diff_transform_start = self.diff_transforms.start().0;
8069        let diff_transform_end = self.diff_transforms.end().0;
8070        debug_assert!(
8071            self.range.start < diff_transform_end,
8072            "{:?} < {:?} of ({1:?}..{2:?})",
8073            self.range.start,
8074            diff_transform_end,
8075            diff_transform_start
8076        );
8077
8078        let diff_transform = self.diff_transforms.item()?;
8079        match diff_transform {
8080            DiffTransform::BufferContent { .. } => {
8081                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8082                    chunk
8083                } else {
8084                    let chunk = self.next_excerpt_chunk().unwrap();
8085                    self.buffer_chunk.insert(chunk)
8086                };
8087
8088                let chunk_end = self.range.start + chunk.text.len();
8089                let diff_transform_end = diff_transform_end.min(self.range.end);
8090
8091                if diff_transform_end < chunk_end {
8092                    let split_idx = diff_transform_end - self.range.start;
8093                    let (before, after) = chunk.text.split_at(split_idx);
8094                    self.range.start = diff_transform_end;
8095                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8096                    let chars = chunk.chars & mask;
8097                    let tabs = chunk.tabs & mask;
8098
8099                    chunk.text = after;
8100                    chunk.chars = chunk.chars >> split_idx;
8101                    chunk.tabs = chunk.tabs >> split_idx;
8102
8103                    Some(Chunk {
8104                        text: before,
8105                        chars,
8106                        tabs,
8107                        ..chunk.clone()
8108                    })
8109                } else {
8110                    self.range.start = chunk_end;
8111                    self.buffer_chunk.take()
8112                }
8113            }
8114            DiffTransform::DeletedHunk {
8115                buffer_id,
8116                base_text_byte_range,
8117                has_trailing_newline,
8118                ..
8119            } => {
8120                let base_text_start =
8121                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8122                let base_text_end =
8123                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8124                let base_text_end = base_text_end.min(base_text_byte_range.end);
8125
8126                let mut chunks = if let Some((_, mut chunks)) = self
8127                    .diff_base_chunks
8128                    .take()
8129                    .filter(|(id, _)| id == buffer_id)
8130                {
8131                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8132                    {
8133                        chunks.seek(base_text_start..base_text_end);
8134                    }
8135                    chunks
8136                } else {
8137                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8138                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8139                };
8140
8141                let chunk = if let Some(chunk) = chunks.next() {
8142                    self.range.start += chunk.text.len();
8143                    self.diff_base_chunks = Some((*buffer_id, chunks));
8144                    chunk
8145                } else {
8146                    debug_assert!(has_trailing_newline);
8147                    self.range.start += "\n".len();
8148                    Chunk {
8149                        text: "\n",
8150                        chars: 1u128,
8151                        ..Default::default()
8152                    }
8153                };
8154                Some(chunk)
8155            }
8156        }
8157    }
8158}
8159
8160impl MultiBufferBytes<'_> {
8161    fn consume(&mut self, len: usize) {
8162        self.range.start += len;
8163        self.chunk = &self.chunk[len..];
8164
8165        if !self.range.is_empty() && self.chunk.is_empty() {
8166            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8167                self.chunk = chunk;
8168            } else if self.has_trailing_newline {
8169                self.has_trailing_newline = false;
8170                self.chunk = b"\n";
8171            } else {
8172                self.cursor.next();
8173                if let Some(region) = self.cursor.region() {
8174                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8175                        region.buffer_range.start
8176                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8177                                .min(region.buffer_range.end),
8178                    );
8179                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8180                    self.excerpt_bytes = Some(excerpt_bytes);
8181                    self.has_trailing_newline =
8182                        region.has_trailing_newline && self.range.end >= region.range.end;
8183                    if self.chunk.is_empty() && self.has_trailing_newline {
8184                        self.has_trailing_newline = false;
8185                        self.chunk = b"\n";
8186                    }
8187                }
8188            }
8189        }
8190    }
8191}
8192
8193impl<'a> Iterator for MultiBufferBytes<'a> {
8194    type Item = &'a [u8];
8195
8196    fn next(&mut self) -> Option<Self::Item> {
8197        let chunk = self.chunk;
8198        if chunk.is_empty() {
8199            None
8200        } else {
8201            self.consume(chunk.len());
8202            Some(chunk)
8203        }
8204    }
8205}
8206
8207impl io::Read for MultiBufferBytes<'_> {
8208    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8209        let len = cmp::min(buf.len(), self.chunk.len());
8210        buf[..len].copy_from_slice(&self.chunk[..len]);
8211        if len > 0 {
8212            self.consume(len);
8213        }
8214        Ok(len)
8215    }
8216}
8217
8218impl io::Read for ReversedMultiBufferBytes<'_> {
8219    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8220        let len = cmp::min(buf.len(), self.chunk.len());
8221        buf[..len].copy_from_slice(&self.chunk[..len]);
8222        buf[..len].reverse();
8223        if len > 0 {
8224            self.range.end -= len;
8225            self.chunk = &self.chunk[..self.chunk.len() - len];
8226            if !self.range.is_empty()
8227                && self.chunk.is_empty()
8228                && let Some(chunk) = self.chunks.next()
8229            {
8230                self.chunk = chunk.as_bytes();
8231            }
8232        }
8233        Ok(len)
8234    }
8235}
8236
8237impl<'a> Iterator for ExcerptChunks<'a> {
8238    type Item = Chunk<'a>;
8239
8240    fn next(&mut self) -> Option<Self::Item> {
8241        if let Some(chunk) = self.content_chunks.next() {
8242            return Some(chunk);
8243        }
8244
8245        if self.has_footer {
8246            let text = "\n";
8247            let chars = 0b1;
8248            self.has_footer = false;
8249            return Some(Chunk {
8250                text,
8251                chars,
8252                ..Default::default()
8253            });
8254        }
8255
8256        None
8257    }
8258}
8259
8260impl ToOffset for Point {
8261    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8262        snapshot.point_to_offset(*self)
8263    }
8264    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8265        snapshot.point_to_offset_utf16(*self)
8266    }
8267}
8268
8269impl ToOffset for MultiBufferOffset {
8270    #[track_caller]
8271    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8272        assert!(
8273            *self <= snapshot.len(),
8274            "offset {} is greater than the snapshot.len() {}",
8275            self.0,
8276            snapshot.len().0,
8277        );
8278        *self
8279    }
8280    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8281        snapshot.offset_to_offset_utf16(*self)
8282    }
8283}
8284
8285impl ToOffset for MultiBufferOffsetUtf16 {
8286    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8287        snapshot.offset_utf16_to_offset(*self)
8288    }
8289
8290    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8291        *self
8292    }
8293}
8294
8295impl ToOffset for PointUtf16 {
8296    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8297        snapshot.point_utf16_to_offset(*self)
8298    }
8299    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8300        snapshot.point_utf16_to_offset_utf16(*self)
8301    }
8302}
8303
8304impl ToPoint for MultiBufferOffset {
8305    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8306        snapshot.offset_to_point(*self)
8307    }
8308    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8309        snapshot.offset_to_point_utf16(*self)
8310    }
8311}
8312
8313impl ToPoint for Point {
8314    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8315        *self
8316    }
8317    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8318        snapshot.point_to_point_utf16(*self)
8319    }
8320}
8321
8322impl ToPoint for PointUtf16 {
8323    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8324        snapshot.point_utf16_to_point(*self)
8325    }
8326    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8327        *self
8328    }
8329}
8330
8331impl From<ExcerptId> for EntityId {
8332    fn from(id: ExcerptId) -> Self {
8333        EntityId::from(id.0 as u64)
8334    }
8335}
8336
8337#[cfg(debug_assertions)]
8338pub mod debug {
8339    use super::*;
8340
8341    pub trait ToMultiBufferDebugRanges {
8342        fn to_multi_buffer_debug_ranges(
8343            &self,
8344            snapshot: &MultiBufferSnapshot,
8345        ) -> Vec<Range<MultiBufferOffset>>;
8346    }
8347
8348    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8349        fn to_multi_buffer_debug_ranges(
8350            &self,
8351            snapshot: &MultiBufferSnapshot,
8352        ) -> Vec<Range<MultiBufferOffset>> {
8353            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8354        }
8355    }
8356
8357    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8358        fn to_multi_buffer_debug_ranges(
8359            &self,
8360            snapshot: &MultiBufferSnapshot,
8361        ) -> Vec<Range<MultiBufferOffset>> {
8362            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8363                .to_multi_buffer_debug_ranges(snapshot)
8364        }
8365    }
8366
8367    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8368        fn to_multi_buffer_debug_ranges(
8369            &self,
8370            snapshot: &MultiBufferSnapshot,
8371        ) -> Vec<Range<MultiBufferOffset>> {
8372            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8373        }
8374    }
8375
8376    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8377        fn to_multi_buffer_debug_ranges(
8378            &self,
8379            snapshot: &MultiBufferSnapshot,
8380        ) -> Vec<Range<MultiBufferOffset>> {
8381            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8382        }
8383    }
8384
8385    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8386        fn to_multi_buffer_debug_ranges(
8387            &self,
8388            snapshot: &MultiBufferSnapshot,
8389        ) -> Vec<Range<MultiBufferOffset>> {
8390            self.iter()
8391                .map(|item| {
8392                    let offset = item.to_offset(snapshot);
8393                    offset..offset
8394                })
8395                .collect()
8396        }
8397    }
8398
8399    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8400        fn to_multi_buffer_debug_ranges(
8401            &self,
8402            snapshot: &MultiBufferSnapshot,
8403        ) -> Vec<Range<MultiBufferOffset>> {
8404            self.iter()
8405                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8406                .collect()
8407        }
8408    }
8409}