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