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 anchor::{AnchorSeekTarget, ExcerptAnchor};
  12use anyhow::{Result, anyhow};
  13use buffer_diff::{
  14    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  15    DiffHunkStatus, DiffHunkStatusKind,
  16};
  17use clock::ReplicaId;
  18use collections::{BTreeMap, Bound, HashMap, HashSet, IndexSet};
  19use gpui::{App, Context, Entity, EventEmitter};
  20use itertools::Itertools;
  21use language::{
  22    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  23    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File, IndentGuideSettings,
  24    IndentSize, Language, LanguageAwareStyling, LanguageScope, OffsetRangeExt, OffsetUtf16,
  25    Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  26    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  27    language_settings::{AllLanguageSettings, LanguageSettings},
  28};
  29
  30#[cfg(any(test, feature = "test-support"))]
  31use gpui::AppContext as _;
  32
  33use rope::DimensionPair;
  34use settings::Settings;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, OnceCell, Ref, RefCell},
  41    cmp::{self, Ordering},
  42    fmt,
  43    future::Future,
  44    io,
  45    iter::{self, FromIterator},
  46    mem,
  47    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  48    rc::Rc,
  49    str,
  50    sync::{Arc, OnceLock},
  51    time::Duration,
  52};
  53use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  54use text::{
  55    BufferId, Edit, LineIndent, TextSummary,
  56    subscription::{Subscription, Topic},
  57};
  58use theme::SyntaxTheme;
  59use unicode_segmentation::UnicodeSegmentation;
  60use ztracing::instrument;
  61
  62pub use self::path_key::PathKey;
  63
  64pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  65
  66pub fn excerpt_context_lines(cx: &App) -> u32 {
  67    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  68}
  69
  70/// One or more [`Buffers`](Buffer) being edited in a single view.
  71///
  72/// See <https://zed.dev/features#multi-buffers>
  73pub struct MultiBuffer {
  74    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  75    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  76    snapshot: RefCell<MultiBufferSnapshot>,
  77    /// Contains the state of the buffers being edited
  78    buffers: BTreeMap<BufferId, BufferState>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic<MultiBufferOffset>,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  95struct PathKeyIndex(u64);
  96
  97#[derive(Clone, Debug, PartialEq, Eq)]
  98pub enum Event {
  99    BufferRangesUpdated {
 100        buffer: Entity<Buffer>,
 101        path_key: PathKey,
 102        ranges: Vec<ExcerptRange<text::Anchor>>,
 103    },
 104    BuffersRemoved {
 105        removed_buffer_ids: Vec<BufferId>,
 106    },
 107    BuffersEdited {
 108        buffer_ids: Vec<BufferId>,
 109    },
 110    DiffHunksToggled,
 111    Edited {
 112        edited_buffer: Option<Entity<Buffer>>,
 113        is_local: bool,
 114    },
 115    TransactionUndone {
 116        transaction_id: TransactionId,
 117    },
 118    Reloaded,
 119    LanguageChanged(BufferId, bool),
 120    Reparsed(BufferId),
 121    Saved,
 122    FileHandleChanged,
 123    DirtyChanged,
 124    DiagnosticsUpdated,
 125    BufferDiffChanged,
 126}
 127
 128/// A diff hunk, representing a range of consequent lines in a multibuffer.
 129#[derive(Debug, Clone, PartialEq, Eq)]
 130pub struct MultiBufferDiffHunk {
 131    /// The row range in the multibuffer where this diff hunk appears.
 132    pub row_range: Range<MultiBufferRow>,
 133    /// The buffer ID that this hunk belongs to.
 134    pub buffer_id: BufferId,
 135    /// The range of the underlying buffer that this hunk corresponds to.
 136    pub buffer_range: Range<text::Anchor>,
 137    /// The range within the buffer's diff base that this hunk corresponds to.
 138    pub diff_base_byte_range: Range<BufferOffset>,
 139    /// The status of this hunk (added/modified/deleted and secondary status).
 140    pub status: DiffHunkStatus,
 141    /// The word diffs for this hunk.
 142    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 143    pub excerpt_range: ExcerptRange<text::Anchor>,
 144    pub multi_buffer_range: Range<Anchor>,
 145}
 146
 147impl MultiBufferDiffHunk {
 148    pub fn status(&self) -> DiffHunkStatus {
 149        self.status
 150    }
 151
 152    pub fn is_created_file(&self) -> bool {
 153        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 154            && self.buffer_range.start.is_min()
 155            && self.buffer_range.end.is_max()
 156    }
 157}
 158
 159pub type MultiBufferPoint = Point;
 160/// ExcerptOffset is offset into the non-deleted text of the multibuffer
 161type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 162/// ExcerptOffset is based on the non-deleted text of the multibuffer
 163
 164#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 165#[serde(transparent)]
 166pub struct MultiBufferRow(pub u32);
 167
 168impl MultiBufferRow {
 169    pub const MIN: Self = Self(0);
 170    pub const MAX: Self = Self(u32::MAX);
 171}
 172
 173impl ops::Add<usize> for MultiBufferRow {
 174    type Output = Self;
 175
 176    fn add(self, rhs: usize) -> Self::Output {
 177        MultiBufferRow(self.0 + rhs as u32)
 178    }
 179}
 180
 181pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 182    type TextDimension: TextDimension;
 183    fn from_summary(summary: &MBTextSummary) -> Self;
 184
 185    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 186
 187    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 188}
 189
 190// todo(lw): MultiBufferPoint
 191impl MultiBufferDimension for Point {
 192    type TextDimension = Point;
 193    fn from_summary(summary: &MBTextSummary) -> Self {
 194        summary.lines
 195    }
 196
 197    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 198        *self += *other;
 199    }
 200
 201    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 202        *self += summary.lines;
 203    }
 204}
 205
 206// todo(lw): MultiBufferPointUtf16
 207impl MultiBufferDimension for PointUtf16 {
 208    type TextDimension = PointUtf16;
 209    fn from_summary(summary: &MBTextSummary) -> Self {
 210        summary.lines_utf16()
 211    }
 212
 213    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 214        *self += *other;
 215    }
 216
 217    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 218        *self += summary.lines_utf16();
 219    }
 220}
 221
 222#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 223pub struct MultiBufferOffset(pub usize);
 224
 225impl fmt::Display for MultiBufferOffset {
 226    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 227        write!(f, "{}", self.0)
 228    }
 229}
 230
 231impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 232    type Sampler = MultiBufferOffsetUniformSampler;
 233}
 234
 235pub struct MultiBufferOffsetUniformSampler {
 236    sampler: rand::distr::uniform::UniformUsize,
 237}
 238
 239impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 240    type X = MultiBufferOffset;
 241
 242    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 243    where
 244        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 245        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 246    {
 247        let low = *low_b.borrow();
 248        let high = *high_b.borrow();
 249        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 250        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 251    }
 252
 253    #[inline] // if the range is constant, this helps LLVM to do the
 254    // calculations at compile-time.
 255    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 256    where
 257        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 258        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259    {
 260        let low = *low_b.borrow();
 261        let high = *high_b.borrow();
 262        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 263        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 264    }
 265
 266    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 267        MultiBufferOffset(self.sampler.sample(rng))
 268    }
 269}
 270impl MultiBufferDimension for MultiBufferOffset {
 271    type TextDimension = usize;
 272    fn from_summary(summary: &MBTextSummary) -> Self {
 273        summary.len
 274    }
 275
 276    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 277        self.0 += *other;
 278    }
 279
 280    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 281        *self += summary.len;
 282    }
 283}
 284impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 285    type TextDimension = OffsetUtf16;
 286    fn from_summary(summary: &MBTextSummary) -> Self {
 287        MultiBufferOffsetUtf16(summary.len_utf16)
 288    }
 289
 290    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 291        self.0 += *other;
 292    }
 293
 294    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 295        self.0 += summary.len_utf16;
 296    }
 297}
 298
 299#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 300pub struct BufferOffset(pub usize);
 301
 302impl TextDimension for BufferOffset {
 303    fn from_text_summary(summary: &TextSummary) -> Self {
 304        BufferOffset(usize::from_text_summary(summary))
 305    }
 306    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 307        BufferOffset(usize::from_chunk(chunk))
 308    }
 309    fn add_assign(&mut self, other: &Self) {
 310        TextDimension::add_assign(&mut self.0, &other.0);
 311    }
 312}
 313impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 314    fn zero(cx: ()) -> Self {
 315        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 316    }
 317
 318    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 319        usize::add_summary(&mut self.0, summary, cx);
 320    }
 321}
 322
 323impl Sub for BufferOffset {
 324    type Output = usize;
 325
 326    fn sub(self, other: BufferOffset) -> Self::Output {
 327        self.0 - other.0
 328    }
 329}
 330
 331impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 332    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 333        self.0 += other.key;
 334    }
 335}
 336
 337impl language::ToPoint for BufferOffset {
 338    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 339        self.0.to_point(snapshot)
 340    }
 341}
 342
 343impl language::ToPointUtf16 for BufferOffset {
 344    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 345        self.0.to_point_utf16(snapshot)
 346    }
 347}
 348
 349impl language::ToOffset for BufferOffset {
 350    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 351        self.0.to_offset(snapshot)
 352    }
 353}
 354
 355impl language::ToOffsetUtf16 for BufferOffset {
 356    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 357        self.0.to_offset_utf16(snapshot)
 358    }
 359}
 360
 361#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 362pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 363
 364impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 365    type Output = MultiBufferOffsetUtf16;
 366
 367    fn add(self, rhs: usize) -> Self::Output {
 368        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 369    }
 370}
 371
 372impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 373    type Output = Self;
 374
 375    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 376        MultiBufferOffsetUtf16(self.0 + rhs)
 377    }
 378}
 379
 380impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 381    fn add_assign(&mut self, rhs: OffsetUtf16) {
 382        self.0 += rhs;
 383    }
 384}
 385
 386impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 387    fn add_assign(&mut self, rhs: usize) {
 388        self.0.0 += rhs;
 389    }
 390}
 391
 392impl Sub for MultiBufferOffsetUtf16 {
 393    type Output = OffsetUtf16;
 394
 395    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 396        self.0 - other.0
 397    }
 398}
 399
 400impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 401    type Output = MultiBufferOffsetUtf16;
 402
 403    fn sub(self, other: OffsetUtf16) -> Self::Output {
 404        MultiBufferOffsetUtf16(self.0 - other)
 405    }
 406}
 407
 408#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 409pub struct BufferOffsetUtf16(pub OffsetUtf16);
 410
 411impl MultiBufferOffset {
 412    const ZERO: Self = Self(0);
 413    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 414        self.0.saturating_sub(other.0)
 415    }
 416    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 417        MultiBufferOffset(self.0.saturating_sub(other))
 418    }
 419}
 420
 421impl ops::Sub for MultiBufferOffset {
 422    type Output = usize;
 423
 424    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 425        self.0 - other.0
 426    }
 427}
 428
 429impl ops::Sub<usize> for MultiBufferOffset {
 430    type Output = Self;
 431
 432    fn sub(self, other: usize) -> Self::Output {
 433        MultiBufferOffset(self.0 - other)
 434    }
 435}
 436
 437impl ops::SubAssign<usize> for MultiBufferOffset {
 438    fn sub_assign(&mut self, other: usize) {
 439        self.0 -= other;
 440    }
 441}
 442
 443impl ops::Add<usize> for BufferOffset {
 444    type Output = Self;
 445
 446    fn add(self, rhs: usize) -> Self::Output {
 447        BufferOffset(self.0 + rhs)
 448    }
 449}
 450
 451impl ops::AddAssign<usize> for BufferOffset {
 452    fn add_assign(&mut self, other: usize) {
 453        self.0 += other;
 454    }
 455}
 456
 457impl ops::Add<usize> for MultiBufferOffset {
 458    type Output = Self;
 459
 460    fn add(self, rhs: usize) -> Self::Output {
 461        MultiBufferOffset(self.0 + rhs)
 462    }
 463}
 464
 465impl ops::AddAssign<usize> for MultiBufferOffset {
 466    fn add_assign(&mut self, other: usize) {
 467        self.0 += other;
 468    }
 469}
 470
 471impl ops::Add<isize> for MultiBufferOffset {
 472    type Output = Self;
 473
 474    fn add(self, rhs: isize) -> Self::Output {
 475        MultiBufferOffset((self.0 as isize + rhs) as usize)
 476    }
 477}
 478
 479impl ops::Add for MultiBufferOffset {
 480    type Output = Self;
 481
 482    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 483        MultiBufferOffset(self.0 + rhs.0)
 484    }
 485}
 486
 487impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 488    fn add_assign(&mut self, other: MultiBufferOffset) {
 489        self.0 += other.0;
 490    }
 491}
 492
 493pub trait ToOffset: 'static + fmt::Debug {
 494    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 495    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 496}
 497
 498pub trait ToPoint: 'static + fmt::Debug {
 499    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 500    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 501}
 502
 503struct BufferState {
 504    buffer: Entity<Buffer>,
 505    _subscriptions: [gpui::Subscription; 2],
 506}
 507
 508struct DiffState {
 509    diff: Entity<BufferDiff>,
 510    main_buffer: Option<Entity<language::Buffer>>,
 511    _subscription: gpui::Subscription,
 512}
 513
 514impl DiffState {
 515    fn snapshot(&self, buffer_id: BufferId, cx: &App) -> DiffStateSnapshot {
 516        DiffStateSnapshot {
 517            buffer_id,
 518            diff: self.diff.read(cx).snapshot(cx),
 519            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 520        }
 521    }
 522}
 523
 524#[derive(Clone)]
 525struct DiffStateSnapshot {
 526    buffer_id: BufferId,
 527    diff: BufferDiffSnapshot,
 528    main_buffer: Option<language::BufferSnapshot>,
 529}
 530
 531impl std::ops::Deref for DiffStateSnapshot {
 532    type Target = BufferDiffSnapshot;
 533
 534    fn deref(&self) -> &Self::Target {
 535        &self.diff
 536    }
 537}
 538
 539#[derive(Clone, Debug, Default)]
 540struct DiffStateSummary {
 541    max_buffer_id: Option<BufferId>,
 542    added_rows: u32,
 543    removed_rows: u32,
 544}
 545
 546impl sum_tree::ContextLessSummary for DiffStateSummary {
 547    fn zero() -> Self {
 548        Self::default()
 549    }
 550
 551    fn add_summary(&mut self, other: &Self) {
 552        self.max_buffer_id = std::cmp::max(self.max_buffer_id, other.max_buffer_id);
 553        self.added_rows += other.added_rows;
 554        self.removed_rows += other.removed_rows;
 555    }
 556}
 557
 558impl sum_tree::Item for DiffStateSnapshot {
 559    type Summary = DiffStateSummary;
 560
 561    fn summary(&self, _cx: ()) -> DiffStateSummary {
 562        let (added_rows, removed_rows) = self.diff.changed_row_counts();
 563        DiffStateSummary {
 564            max_buffer_id: Some(self.buffer_id),
 565            added_rows,
 566            removed_rows,
 567        }
 568    }
 569}
 570
 571impl sum_tree::KeyedItem for DiffStateSnapshot {
 572    type Key = Option<BufferId>;
 573
 574    fn key(&self) -> Option<BufferId> {
 575        Some(self.buffer_id)
 576    }
 577}
 578
 579impl<'a> Dimension<'a, DiffStateSummary> for Option<BufferId> {
 580    fn zero(_cx: ()) -> Self {
 581        None
 582    }
 583
 584    fn add_summary(&mut self, summary: &DiffStateSummary, _cx: ()) {
 585        *self = std::cmp::max(*self, summary.max_buffer_id);
 586    }
 587}
 588
 589fn find_diff_state(
 590    diffs: &SumTree<DiffStateSnapshot>,
 591    buffer_id: BufferId,
 592) -> Option<&DiffStateSnapshot> {
 593    let key = Some(buffer_id);
 594    let (.., item) = diffs.find::<Option<BufferId>, _>((), &key, Bias::Left);
 595    item.filter(|entry| entry.buffer_id == buffer_id)
 596}
 597
 598fn remove_diff_state(diffs: &mut SumTree<DiffStateSnapshot>, buffer_id: BufferId) {
 599    let key = Some(buffer_id);
 600    let mut cursor = diffs.cursor::<Option<BufferId>>(());
 601    let mut new_tree = cursor.slice(&key, Bias::Left);
 602    if key == cursor.end() {
 603        cursor.next();
 604    }
 605    new_tree.append(cursor.suffix(), ());
 606    drop(cursor);
 607    *diffs = new_tree;
 608}
 609
 610impl DiffState {
 611    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 612        DiffState {
 613            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 614                BufferDiffEvent::DiffChanged(DiffChanged {
 615                    changed_range,
 616                    base_text_changed_range: _,
 617                    extended_range,
 618                }) => {
 619                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 620                    let range = if use_extended {
 621                        extended_range.clone()
 622                    } else {
 623                        changed_range.clone()
 624                    };
 625                    if let Some(range) = range {
 626                        this.buffer_diff_changed(diff, range, cx)
 627                    }
 628                    cx.emit(Event::BufferDiffChanged);
 629                }
 630                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 631                _ => {}
 632            }),
 633            diff,
 634            main_buffer: None,
 635        }
 636    }
 637
 638    fn new_inverted(
 639        diff: Entity<BufferDiff>,
 640        main_buffer: Entity<language::Buffer>,
 641        cx: &mut Context<MultiBuffer>,
 642    ) -> Self {
 643        let weak_main_buffer = main_buffer.downgrade();
 644        DiffState {
 645            _subscription: cx.subscribe(&diff, {
 646                move |this, diff, event, cx| {
 647                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 648                        return;
 649                    };
 650                    match event {
 651                        BufferDiffEvent::DiffChanged(DiffChanged {
 652                            changed_range: _,
 653                            base_text_changed_range,
 654                            extended_range: _,
 655                        }) => {
 656                            this.inverted_buffer_diff_changed(
 657                                diff,
 658                                main_buffer,
 659                                base_text_changed_range.clone(),
 660                                cx,
 661                            );
 662                            cx.emit(Event::BufferDiffChanged);
 663                        }
 664                        BufferDiffEvent::LanguageChanged => {
 665                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 666                        }
 667                        _ => {}
 668                    }
 669                }
 670            }),
 671            diff,
 672            main_buffer: Some(main_buffer),
 673        }
 674    }
 675}
 676
 677#[derive(Clone)]
 678struct BufferStateSnapshot {
 679    pub(crate) path_key: PathKey,
 680    path_key_index: PathKeyIndex,
 681    buffer_snapshot: BufferSnapshot,
 682}
 683
 684impl fmt::Debug for BufferStateSnapshot {
 685    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 686        f.debug_struct("BufferStateSnapshot")
 687            .field("path_key", &self.path_key)
 688            .field("buffer_id", &self.buffer_snapshot.remote_id())
 689            .finish()
 690    }
 691}
 692
 693/// The contents of a [`MultiBuffer`] at a single point in time.
 694#[derive(Clone, Default)]
 695pub struct MultiBufferSnapshot {
 696    excerpts: SumTree<Excerpt>,
 697    buffers: TreeMap<BufferId, BufferStateSnapshot>,
 698    path_keys: Arc<IndexSet<PathKey>>,
 699    diffs: SumTree<DiffStateSnapshot>,
 700    diff_transforms: SumTree<DiffTransform>,
 701    non_text_state_update_count: usize,
 702    edit_count: usize,
 703    is_dirty: bool,
 704    has_deleted_file: bool,
 705    has_conflict: bool,
 706    has_inverted_diff: bool,
 707    singleton: bool,
 708    trailing_excerpt_update_count: usize,
 709    all_diff_hunks_expanded: bool,
 710    show_deleted_hunks: bool,
 711    use_extended_diff_range: bool,
 712    show_headers: bool,
 713}
 714
 715#[derive(Debug, Clone)]
 716enum DiffTransform {
 717    BufferContent {
 718        summary: MBTextSummary,
 719        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 720    },
 721    DeletedHunk {
 722        summary: TextSummary,
 723        buffer_id: BufferId,
 724        hunk_info: DiffTransformHunkInfo,
 725        base_text_byte_range: Range<usize>,
 726        has_trailing_newline: bool,
 727    },
 728}
 729
 730#[derive(Clone, Copy, Debug)]
 731struct DiffTransformHunkInfo {
 732    buffer_id: BufferId,
 733    hunk_start_anchor: text::Anchor,
 734    hunk_secondary_status: DiffHunkSecondaryStatus,
 735    is_logically_deleted: bool,
 736    excerpt_end: ExcerptAnchor,
 737}
 738
 739impl Eq for DiffTransformHunkInfo {}
 740
 741impl PartialEq for DiffTransformHunkInfo {
 742    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 743        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 744    }
 745}
 746
 747impl std::hash::Hash for DiffTransformHunkInfo {
 748    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 749        self.buffer_id.hash(state);
 750        self.hunk_start_anchor.hash(state);
 751    }
 752}
 753
 754#[derive(Clone)]
 755pub struct ExcerptBoundaryInfo {
 756    pub start_anchor: Anchor,
 757    pub range: ExcerptRange<text::Anchor>,
 758    pub end_row: MultiBufferRow,
 759}
 760
 761impl ExcerptBoundaryInfo {
 762    pub fn start_text_anchor(&self) -> text::Anchor {
 763        self.range.context.start
 764    }
 765    pub fn buffer_id(&self) -> BufferId {
 766        self.start_text_anchor().buffer_id
 767    }
 768    pub fn buffer<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
 769        snapshot
 770            .buffer_for_id(self.buffer_id())
 771            .expect("buffer snapshot not found for excerpt boundary")
 772    }
 773}
 774
 775impl std::fmt::Debug for ExcerptBoundaryInfo {
 776    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 777        f.debug_struct(type_name::<Self>())
 778            .field("buffer_id", &self.buffer_id())
 779            .field("range", &self.range)
 780            .finish()
 781    }
 782}
 783
 784impl PartialEq for ExcerptBoundaryInfo {
 785    fn eq(&self, other: &Self) -> bool {
 786        self.start_anchor == other.start_anchor && self.range == other.range
 787    }
 788}
 789
 790impl Eq for ExcerptBoundaryInfo {}
 791
 792/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 793#[derive(Debug)]
 794pub struct ExcerptBoundary {
 795    pub prev: Option<ExcerptBoundaryInfo>,
 796    pub next: ExcerptBoundaryInfo,
 797    /// The row in the `MultiBuffer` where the boundary is located
 798    pub row: MultiBufferRow,
 799}
 800
 801impl ExcerptBoundary {
 802    pub fn starts_new_buffer(&self) -> bool {
 803        match (self.prev.as_ref(), &self.next) {
 804            (None, _) => true,
 805            (Some(prev), next) => prev.buffer_id() != next.buffer_id(),
 806        }
 807    }
 808}
 809
 810#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 811pub struct ExpandInfo {
 812    pub direction: ExpandExcerptDirection,
 813    pub start_anchor: Anchor,
 814}
 815
 816#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 817pub struct RowInfo {
 818    pub buffer_id: Option<BufferId>,
 819    pub buffer_row: Option<u32>,
 820    pub multibuffer_row: Option<MultiBufferRow>,
 821    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 822    pub expand_info: Option<ExpandInfo>,
 823    pub wrapped_buffer_row: Option<u32>,
 824}
 825
 826/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 827#[derive(Clone, Debug)]
 828pub(crate) struct Excerpt {
 829    /// The location of the excerpt in the [`MultiBuffer`]
 830    pub(crate) path_key: PathKey,
 831    pub(crate) path_key_index: PathKeyIndex,
 832    pub(crate) buffer_id: BufferId,
 833    /// The range of the buffer to be shown in the excerpt
 834    pub(crate) range: ExcerptRange<text::Anchor>,
 835
 836    /// The last row in the excerpted slice of the buffer
 837    pub(crate) max_buffer_row: BufferRow,
 838    /// A summary of the text in the excerpt
 839    pub(crate) text_summary: TextSummary,
 840    pub(crate) has_trailing_newline: bool,
 841}
 842
 843/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 844/// These ranges are relative to the buffer itself
 845#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 846pub struct ExcerptRange<T> {
 847    /// The full range of text to be shown in the excerpt.
 848    pub context: Range<T>,
 849    /// The primary range of text to be highlighted in the excerpt.
 850    /// In a multi-buffer search, this would be the text that matched the search
 851    pub primary: Range<T>,
 852}
 853
 854impl<T: Clone> ExcerptRange<T> {
 855    pub fn new(context: Range<T>) -> Self {
 856        Self {
 857            context: context.clone(),
 858            primary: context,
 859        }
 860    }
 861}
 862
 863impl ExcerptRange<text::Anchor> {
 864    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 865        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 866    }
 867}
 868
 869#[derive(Clone, Debug)]
 870pub struct ExcerptSummary {
 871    path_key: PathKey,
 872    path_key_index: Option<PathKeyIndex>,
 873    max_anchor: Option<text::Anchor>,
 874    widest_line_number: u32,
 875    text: MBTextSummary,
 876    count: usize,
 877}
 878
 879impl ExcerptSummary {
 880    pub fn min() -> Self {
 881        ExcerptSummary {
 882            path_key: PathKey::min(),
 883            path_key_index: None,
 884            max_anchor: None,
 885            widest_line_number: 0,
 886            text: MBTextSummary::default(),
 887            count: 0,
 888        }
 889    }
 890
 891    fn len(&self) -> ExcerptOffset {
 892        ExcerptDimension(self.text.len)
 893    }
 894}
 895
 896#[derive(Debug, Clone)]
 897pub struct DiffTransformSummary {
 898    input: MBTextSummary,
 899    output: MBTextSummary,
 900}
 901
 902/// Summary of a string of text.
 903#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 904pub struct MBTextSummary {
 905    /// Length in bytes.
 906    pub len: MultiBufferOffset,
 907    /// Length in UTF-8.
 908    pub chars: usize,
 909    /// Length in UTF-16 code units
 910    pub len_utf16: OffsetUtf16,
 911    /// A point representing the number of lines and the length of the last line.
 912    ///
 913    /// In other words, it marks the point after the last byte in the text, (if
 914    /// EOF was a character, this would be its position).
 915    pub lines: Point,
 916    /// How many `char`s are in the first line
 917    pub first_line_chars: u32,
 918    /// How many `char`s are in the last line
 919    pub last_line_chars: u32,
 920    /// How many UTF-16 code units are in the last line
 921    pub last_line_len_utf16: u32,
 922    /// The row idx of the longest row
 923    pub longest_row: u32,
 924    /// How many `char`s are in the longest row
 925    pub longest_row_chars: u32,
 926}
 927
 928impl From<TextSummary> for MBTextSummary {
 929    fn from(summary: TextSummary) -> Self {
 930        MBTextSummary {
 931            len: MultiBufferOffset(summary.len),
 932            chars: summary.chars,
 933            len_utf16: summary.len_utf16,
 934            lines: summary.lines,
 935            first_line_chars: summary.first_line_chars,
 936            last_line_chars: summary.last_line_chars,
 937            last_line_len_utf16: summary.last_line_len_utf16,
 938            longest_row: summary.longest_row,
 939            longest_row_chars: summary.longest_row_chars,
 940        }
 941    }
 942}
 943
 944impl From<MBTextSummary> for TextSummary {
 945    fn from(summary: MBTextSummary) -> Self {
 946        TextSummary {
 947            len: summary.len.0,
 948            chars: summary.chars,
 949            len_utf16: summary.len_utf16,
 950            lines: summary.lines,
 951            first_line_chars: summary.first_line_chars,
 952            last_line_chars: summary.last_line_chars,
 953            last_line_len_utf16: summary.last_line_len_utf16,
 954            longest_row: summary.longest_row,
 955            longest_row_chars: summary.longest_row_chars,
 956        }
 957    }
 958}
 959
 960impl From<&str> for MBTextSummary {
 961    fn from(text: &str) -> Self {
 962        MBTextSummary::from(TextSummary::from(text))
 963    }
 964}
 965
 966impl MultiBufferDimension for MBTextSummary {
 967    type TextDimension = TextSummary;
 968
 969    fn from_summary(summary: &MBTextSummary) -> Self {
 970        *summary
 971    }
 972
 973    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 974        *self += *summary;
 975    }
 976
 977    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 978        *self += *summary;
 979    }
 980}
 981
 982impl AddAssign for MBTextSummary {
 983    fn add_assign(&mut self, other: MBTextSummary) {
 984        let joined_chars = self.last_line_chars + other.first_line_chars;
 985        if joined_chars > self.longest_row_chars {
 986            self.longest_row = self.lines.row;
 987            self.longest_row_chars = joined_chars;
 988        }
 989        if other.longest_row_chars > self.longest_row_chars {
 990            self.longest_row = self.lines.row + other.longest_row;
 991            self.longest_row_chars = other.longest_row_chars;
 992        }
 993
 994        if self.lines.row == 0 {
 995            self.first_line_chars += other.first_line_chars;
 996        }
 997
 998        if other.lines.row == 0 {
 999            self.last_line_chars += other.first_line_chars;
1000            self.last_line_len_utf16 += other.last_line_len_utf16;
1001        } else {
1002            self.last_line_chars = other.last_line_chars;
1003            self.last_line_len_utf16 = other.last_line_len_utf16;
1004        }
1005
1006        self.chars += other.chars;
1007        self.len += other.len;
1008        self.len_utf16 += other.len_utf16;
1009        self.lines += other.lines;
1010    }
1011}
1012
1013impl AddAssign<TextSummary> for MBTextSummary {
1014    fn add_assign(&mut self, other: TextSummary) {
1015        *self += MBTextSummary::from(other);
1016    }
1017}
1018
1019impl MBTextSummary {
1020    pub fn lines_utf16(&self) -> PointUtf16 {
1021        PointUtf16 {
1022            row: self.lines.row,
1023            column: self.last_line_len_utf16,
1024        }
1025    }
1026}
1027
1028impl<K, V> MultiBufferDimension for DimensionPair<K, V>
1029where
1030    K: MultiBufferDimension,
1031    V: MultiBufferDimension,
1032{
1033    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
1034
1035    fn from_summary(summary: &MBTextSummary) -> Self {
1036        Self {
1037            key: K::from_summary(summary),
1038            value: Some(V::from_summary(summary)),
1039        }
1040    }
1041
1042    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
1043        self.key.add_text_dim(&summary.key);
1044        if let Some(value) = &mut self.value {
1045            if let Some(other_value) = summary.value.as_ref() {
1046                value.add_text_dim(other_value);
1047            }
1048        }
1049    }
1050
1051    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
1052        self.key.add_mb_text_summary(summary);
1053        if let Some(value) = &mut self.value {
1054            value.add_mb_text_summary(summary);
1055        }
1056    }
1057}
1058
1059#[derive(Clone)]
1060pub struct MultiBufferRows<'a> {
1061    point: Point,
1062    is_empty: bool,
1063    is_singleton: bool,
1064    cursor: MultiBufferCursor<'a, Point, Point>,
1065}
1066
1067pub struct MultiBufferChunks<'a> {
1068    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
1069    diff_transforms:
1070        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
1071    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
1072    buffer_chunk: Option<Chunk<'a>>,
1073    range: Range<MultiBufferOffset>,
1074    excerpt_offset_range: Range<ExcerptOffset>,
1075    excerpt_chunks: Option<ExcerptChunks<'a>>,
1076    language_aware: LanguageAwareStyling,
1077    snapshot: &'a MultiBufferSnapshot,
1078}
1079
1080pub struct ReversedMultiBufferChunks<'a> {
1081    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1082    current_chunks: Option<rope::Chunks<'a>>,
1083    start: MultiBufferOffset,
1084    offset: MultiBufferOffset,
1085}
1086
1087pub struct MultiBufferBytes<'a> {
1088    range: Range<MultiBufferOffset>,
1089    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1090    excerpt_bytes: Option<text::Bytes<'a>>,
1091    has_trailing_newline: bool,
1092    chunk: &'a [u8],
1093}
1094
1095pub struct ReversedMultiBufferBytes<'a> {
1096    range: Range<MultiBufferOffset>,
1097    chunks: ReversedMultiBufferChunks<'a>,
1098    chunk: &'a [u8],
1099}
1100
1101#[derive(Clone)]
1102struct DiffTransforms<MBD> {
1103    output_dimension: OutputDimension<MBD>,
1104    excerpt_dimension: ExcerptDimension<MBD>,
1105}
1106
1107impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1108    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1109        Self {
1110            output_dimension: OutputDimension::zero(cx),
1111            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1112                cx,
1113            ),
1114        }
1115    }
1116
1117    fn add_summary(
1118        &mut self,
1119        summary: &'a DiffTransformSummary,
1120        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1121    ) {
1122        self.output_dimension.add_summary(summary, cx);
1123        self.excerpt_dimension.add_summary(summary, cx);
1124    }
1125}
1126
1127#[derive(Clone)]
1128struct MultiBufferCursor<'a, MBD, BD> {
1129    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1130    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1131    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1132    snapshot: &'a MultiBufferSnapshot,
1133}
1134
1135#[derive(Clone)]
1136struct MultiBufferRegion<'a, MBD, BD> {
1137    buffer: &'a BufferSnapshot,
1138    is_main_buffer: bool,
1139    diff_hunk_status: Option<DiffHunkStatus>,
1140    excerpt: &'a Excerpt,
1141    buffer_range: Range<BD>,
1142    range: Range<MBD>,
1143    has_trailing_newline: bool,
1144}
1145
1146struct ExcerptChunks<'a> {
1147    content_chunks: BufferChunks<'a>,
1148    end: ExcerptAnchor,
1149    has_footer: bool,
1150}
1151
1152#[derive(Debug)]
1153struct BufferEdit {
1154    range: Range<BufferOffset>,
1155    new_text: Arc<str>,
1156    is_insertion: bool,
1157    original_indent_column: Option<u32>,
1158}
1159
1160#[derive(Clone, Copy, Debug, PartialEq)]
1161enum DiffChangeKind {
1162    BufferEdited,
1163    DiffUpdated { base_changed: bool },
1164    ExpandOrCollapseHunks { expand: bool },
1165}
1166
1167#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1168pub enum ExpandExcerptDirection {
1169    Up,
1170    Down,
1171    UpAndDown,
1172}
1173
1174impl ExpandExcerptDirection {
1175    pub fn should_expand_up(&self) -> bool {
1176        match self {
1177            ExpandExcerptDirection::Up => true,
1178            ExpandExcerptDirection::Down => false,
1179            ExpandExcerptDirection::UpAndDown => true,
1180        }
1181    }
1182
1183    pub fn should_expand_down(&self) -> bool {
1184        match self {
1185            ExpandExcerptDirection::Up => false,
1186            ExpandExcerptDirection::Down => true,
1187            ExpandExcerptDirection::UpAndDown => true,
1188        }
1189    }
1190}
1191
1192#[derive(Clone, Debug, PartialEq)]
1193pub struct IndentGuide {
1194    pub buffer_id: BufferId,
1195    pub start_row: MultiBufferRow,
1196    pub end_row: MultiBufferRow,
1197    pub depth: u32,
1198    pub tab_size: u32,
1199    pub settings: IndentGuideSettings,
1200}
1201
1202impl IndentGuide {
1203    pub fn indent_level(&self) -> u32 {
1204        self.depth * self.tab_size
1205    }
1206}
1207
1208impl MultiBuffer {
1209    pub fn new(capability: Capability) -> Self {
1210        Self::new_(
1211            capability,
1212            MultiBufferSnapshot {
1213                show_headers: true,
1214                show_deleted_hunks: true,
1215                ..MultiBufferSnapshot::default()
1216            },
1217        )
1218    }
1219
1220    pub fn without_headers(capability: Capability) -> Self {
1221        Self::new_(
1222            capability,
1223            MultiBufferSnapshot {
1224                show_deleted_hunks: true,
1225                ..MultiBufferSnapshot::default()
1226            },
1227        )
1228    }
1229
1230    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1231        let mut this = Self::new_(
1232            buffer.read(cx).capability(),
1233            MultiBufferSnapshot {
1234                singleton: true,
1235                show_deleted_hunks: true,
1236                ..MultiBufferSnapshot::default()
1237            },
1238        );
1239        this.singleton = true;
1240        this.set_excerpts_for_path(
1241            PathKey::sorted(0),
1242            buffer.clone(),
1243            [Point::zero()..buffer.read(cx).max_point()],
1244            0,
1245            cx,
1246        );
1247        this
1248    }
1249
1250    #[inline]
1251    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1252        Self {
1253            snapshot: RefCell::new(snapshot),
1254            buffers: Default::default(),
1255            diffs: HashMap::default(),
1256            subscriptions: Topic::default(),
1257            singleton: false,
1258            capability,
1259            title: None,
1260            buffer_changed_since_sync: Default::default(),
1261            history: History::default(),
1262        }
1263    }
1264
1265    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1266        let mut buffers = BTreeMap::default();
1267        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1268        for (buffer_id, buffer_state) in self.buffers.iter() {
1269            buffer_state.buffer.update(new_cx, |buffer, _| {
1270                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1271            });
1272            buffers.insert(
1273                *buffer_id,
1274                BufferState {
1275                    buffer: buffer_state.buffer.clone(),
1276                    _subscriptions: [
1277                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1278                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1279                    ],
1280                },
1281            );
1282        }
1283        let mut diff_bases = HashMap::default();
1284        for (buffer_id, diff) in self.diffs.iter() {
1285            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1286        }
1287        Self {
1288            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1289            buffers,
1290            diffs: diff_bases,
1291            subscriptions: Default::default(),
1292            singleton: self.singleton,
1293            capability: self.capability,
1294            history: self.history.clone(),
1295            title: self.title.clone(),
1296            buffer_changed_since_sync,
1297        }
1298    }
1299
1300    pub fn set_group_interval(&mut self, group_interval: Duration, cx: &mut Context<Self>) {
1301        self.history.set_group_interval(group_interval);
1302        if self.singleton {
1303            for BufferState { buffer, .. } in self.buffers.values() {
1304                buffer.update(cx, |buffer, _| {
1305                    buffer.set_group_interval(group_interval);
1306                });
1307            }
1308        }
1309    }
1310
1311    pub fn with_title(mut self, title: String) -> Self {
1312        self.title = Some(title);
1313        self
1314    }
1315
1316    pub fn read_only(&self) -> bool {
1317        !self.capability.editable()
1318    }
1319
1320    pub fn capability(&self) -> Capability {
1321        self.capability
1322    }
1323
1324    /// Returns an up-to-date snapshot of the MultiBuffer.
1325    #[ztracing::instrument(skip_all)]
1326    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1327        self.sync(cx);
1328        self.snapshot.borrow().clone()
1329    }
1330
1331    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1332        self.sync(cx);
1333        self.snapshot.borrow()
1334    }
1335
1336    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1337        if self.singleton {
1338            Some(self.buffers.values().next().unwrap().buffer.clone())
1339        } else {
1340            None
1341        }
1342    }
1343
1344    pub fn is_singleton(&self) -> bool {
1345        self.singleton
1346    }
1347
1348    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1349        self.subscriptions.subscribe()
1350    }
1351
1352    pub fn is_dirty(&self, cx: &App) -> bool {
1353        self.read(cx).is_dirty()
1354    }
1355
1356    pub fn has_deleted_file(&self, cx: &App) -> bool {
1357        self.read(cx).has_deleted_file()
1358    }
1359
1360    pub fn has_conflict(&self, cx: &App) -> bool {
1361        self.read(cx).has_conflict()
1362    }
1363
1364    // The `is_empty` signature doesn't match what clippy expects
1365    #[allow(clippy::len_without_is_empty)]
1366    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1367        self.read(cx).len()
1368    }
1369
1370    pub fn is_empty(&self) -> bool {
1371        self.buffers.is_empty()
1372    }
1373
1374    pub fn edit<I, S, T>(
1375        &mut self,
1376        edits: I,
1377        autoindent_mode: Option<AutoindentMode>,
1378        cx: &mut Context<Self>,
1379    ) where
1380        I: IntoIterator<Item = (Range<S>, T)>,
1381        S: ToOffset,
1382        T: Into<Arc<str>>,
1383    {
1384        self.edit_internal(edits, autoindent_mode, true, cx);
1385    }
1386
1387    pub fn edit_non_coalesce<I, S, T>(
1388        &mut self,
1389        edits: I,
1390        autoindent_mode: Option<AutoindentMode>,
1391        cx: &mut Context<Self>,
1392    ) where
1393        I: IntoIterator<Item = (Range<S>, T)>,
1394        S: ToOffset,
1395        T: Into<Arc<str>>,
1396    {
1397        self.edit_internal(edits, autoindent_mode, false, cx);
1398    }
1399
1400    fn edit_internal<I, S, T>(
1401        &mut self,
1402        edits: I,
1403        autoindent_mode: Option<AutoindentMode>,
1404        coalesce_adjacent: bool,
1405        cx: &mut Context<Self>,
1406    ) where
1407        I: IntoIterator<Item = (Range<S>, T)>,
1408        S: ToOffset,
1409        T: Into<Arc<str>>,
1410    {
1411        if self.read_only() || self.buffers.is_empty() {
1412            return;
1413        }
1414        self.sync_mut(cx);
1415        let edits = edits
1416            .into_iter()
1417            .map(|(range, new_text)| {
1418                let mut range = range.start.to_offset(self.snapshot.get_mut())
1419                    ..range.end.to_offset(self.snapshot.get_mut());
1420                if range.start > range.end {
1421                    mem::swap(&mut range.start, &mut range.end);
1422                }
1423                (range, new_text.into())
1424            })
1425            .collect::<Vec<_>>();
1426
1427        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1428
1429        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1430        fn edit_internal(
1431            this: &mut MultiBuffer,
1432            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1433            mut autoindent_mode: Option<AutoindentMode>,
1434            coalesce_adjacent: bool,
1435            cx: &mut Context<MultiBuffer>,
1436        ) {
1437            let original_indent_columns = match &mut autoindent_mode {
1438                Some(AutoindentMode::Block {
1439                    original_indent_columns,
1440                }) => mem::take(original_indent_columns),
1441                _ => Default::default(),
1442            };
1443
1444            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1445                edits,
1446                this.snapshot.get_mut(),
1447                &original_indent_columns,
1448            );
1449
1450            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1451            for (buffer_id, mut edits) in buffer_edits {
1452                buffer_ids.push(buffer_id);
1453                edits.sort_by_key(|edit| edit.range.start);
1454                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1455                    let mut edits = edits.into_iter().peekable();
1456                    let mut insertions = Vec::new();
1457                    let mut original_indent_columns = Vec::new();
1458                    let mut deletions = Vec::new();
1459                    let empty_str: Arc<str> = Arc::default();
1460                    while let Some(BufferEdit {
1461                        mut range,
1462                        mut new_text,
1463                        mut is_insertion,
1464                        original_indent_column,
1465                    }) = edits.next()
1466                    {
1467                        while let Some(BufferEdit {
1468                            range: next_range,
1469                            is_insertion: next_is_insertion,
1470                            new_text: next_new_text,
1471                            ..
1472                        }) = edits.peek()
1473                        {
1474                            let should_coalesce = if coalesce_adjacent {
1475                                range.end >= next_range.start
1476                            } else {
1477                                range.end > next_range.start
1478                            };
1479
1480                            if should_coalesce {
1481                                range.end = cmp::max(next_range.end, range.end);
1482                                is_insertion |= *next_is_insertion;
1483                                new_text = format!("{new_text}{next_new_text}").into();
1484                                edits.next();
1485                            } else {
1486                                break;
1487                            }
1488                        }
1489
1490                        if is_insertion {
1491                            original_indent_columns.push(original_indent_column);
1492                            insertions.push((
1493                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1494                                new_text.clone(),
1495                            ));
1496                        } else if !range.is_empty() {
1497                            deletions.push((
1498                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1499                                empty_str.clone(),
1500                            ));
1501                        }
1502                    }
1503
1504                    let deletion_autoindent_mode =
1505                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1506                            Some(AutoindentMode::Block {
1507                                original_indent_columns: Default::default(),
1508                            })
1509                        } else {
1510                            autoindent_mode.clone()
1511                        };
1512                    let insertion_autoindent_mode =
1513                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1514                            Some(AutoindentMode::Block {
1515                                original_indent_columns,
1516                            })
1517                        } else {
1518                            autoindent_mode.clone()
1519                        };
1520
1521                    if coalesce_adjacent {
1522                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1523                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1524                    } else {
1525                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1526                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1527                    }
1528                })
1529            }
1530
1531            cx.emit(Event::BuffersEdited { buffer_ids });
1532        }
1533    }
1534
1535    fn convert_edits_to_buffer_edits(
1536        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1537        snapshot: &MultiBufferSnapshot,
1538        original_indent_columns: &[Option<u32>],
1539    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1540        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1541        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1542        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1543            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1544
1545            cursor.seek(&range.start);
1546            let mut start_region = cursor.region().expect("start offset out of bounds");
1547            if !start_region.is_main_buffer {
1548                cursor.next();
1549                if let Some(region) = cursor.region() {
1550                    start_region = region;
1551                } else {
1552                    continue;
1553                }
1554            }
1555
1556            if range.end < start_region.range.start {
1557                continue;
1558            }
1559
1560            let start_region = start_region.clone();
1561            if range.end > start_region.range.end {
1562                cursor.seek_forward(&range.end);
1563            }
1564            let mut end_region = cursor.region().expect("end offset out of bounds");
1565            if !end_region.is_main_buffer {
1566                cursor.prev();
1567                if let Some(region) = cursor.region() {
1568                    end_region = region;
1569                } else {
1570                    continue;
1571                }
1572            }
1573
1574            if range.start > end_region.range.end {
1575                continue;
1576            }
1577
1578            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1579            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1580            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1581                .min(start_region.buffer_range.end);
1582            let buffer_end =
1583                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1584
1585            if start_region.excerpt == end_region.excerpt {
1586                if start_region.buffer.capability == Capability::ReadWrite
1587                    && start_region.is_main_buffer
1588                {
1589                    buffer_edits
1590                        .entry(start_region.buffer.remote_id())
1591                        .or_default()
1592                        .push(BufferEdit {
1593                            range: buffer_start..buffer_end,
1594                            new_text,
1595                            is_insertion: true,
1596                            original_indent_column,
1597                        });
1598                }
1599            } else {
1600                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1601                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1602                if start_region.buffer.capability == Capability::ReadWrite
1603                    && start_region.is_main_buffer
1604                {
1605                    buffer_edits
1606                        .entry(start_region.buffer.remote_id())
1607                        .or_default()
1608                        .push(BufferEdit {
1609                            range: start_excerpt_range,
1610                            new_text: new_text.clone(),
1611                            is_insertion: true,
1612                            original_indent_column,
1613                        });
1614                }
1615                if end_region.buffer.capability == Capability::ReadWrite
1616                    && end_region.is_main_buffer
1617                {
1618                    buffer_edits
1619                        .entry(end_region.buffer.remote_id())
1620                        .or_default()
1621                        .push(BufferEdit {
1622                            range: end_excerpt_range,
1623                            new_text: new_text.clone(),
1624                            is_insertion: false,
1625                            original_indent_column,
1626                        });
1627                }
1628                let end_region_excerpt = end_region.excerpt.clone();
1629
1630                cursor.seek(&range.start);
1631                cursor.next_excerpt();
1632                while let Some(region) = cursor.region() {
1633                    if region.excerpt == &end_region_excerpt {
1634                        break;
1635                    }
1636                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1637                        buffer_edits
1638                            .entry(region.buffer.remote_id())
1639                            .or_default()
1640                            .push(BufferEdit {
1641                                range: region.buffer_range.clone(),
1642                                new_text: new_text.clone(),
1643                                is_insertion: false,
1644                                original_indent_column,
1645                            });
1646                    }
1647                    cursor.next_excerpt();
1648                }
1649            }
1650        }
1651        buffer_edits
1652    }
1653
1654    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1655    where
1656        I: IntoIterator<Item = Range<S>>,
1657        S: ToOffset,
1658    {
1659        if self.read_only() || self.buffers.is_empty() {
1660            return;
1661        }
1662        self.sync_mut(cx);
1663        let empty = Arc::<str>::from("");
1664        let edits = ranges
1665            .into_iter()
1666            .map(|range| {
1667                let mut range = range.start.to_offset(self.snapshot.get_mut())
1668                    ..range.end.to_offset(&self.snapshot.get_mut());
1669                if range.start > range.end {
1670                    mem::swap(&mut range.start, &mut range.end);
1671                }
1672                (range, empty.clone())
1673            })
1674            .collect::<Vec<_>>();
1675
1676        return autoindent_ranges_internal(self, edits, cx);
1677
1678        fn autoindent_ranges_internal(
1679            this: &mut MultiBuffer,
1680            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1681            cx: &mut Context<MultiBuffer>,
1682        ) {
1683            let buffer_edits =
1684                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1685
1686            let mut buffer_ids = Vec::new();
1687            for (buffer_id, mut edits) in buffer_edits {
1688                buffer_ids.push(buffer_id);
1689                edits.sort_unstable_by_key(|edit| edit.range.start);
1690
1691                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1692                for edit in edits {
1693                    if let Some(last_range) = ranges.last_mut()
1694                        && edit.range.start <= last_range.end
1695                    {
1696                        last_range.end = last_range.end.max(edit.range.end);
1697                        continue;
1698                    }
1699                    ranges.push(edit.range);
1700                }
1701
1702                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1703                    buffer.autoindent_ranges(ranges, cx);
1704                })
1705            }
1706
1707            cx.emit(Event::BuffersEdited { buffer_ids });
1708        }
1709    }
1710
1711    pub fn set_active_selections(
1712        &self,
1713        selections: &[Selection<Anchor>],
1714        line_mode: bool,
1715        cursor_shape: CursorShape,
1716        cx: &mut Context<Self>,
1717    ) {
1718        let snapshot = self.snapshot(cx);
1719        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1720            Default::default();
1721
1722        for selection in selections {
1723            for (buffer_snapshot, buffer_range, _) in
1724                snapshot.range_to_buffer_ranges(selection.start..selection.end)
1725            {
1726                selections_by_buffer
1727                    .entry(buffer_snapshot.remote_id())
1728                    .or_default()
1729                    .push(Selection {
1730                        id: selection.id,
1731                        start: buffer_snapshot
1732                            .anchor_at(buffer_range.start, selection.start.bias()),
1733                        end: buffer_snapshot.anchor_at(buffer_range.end, selection.end.bias()),
1734                        reversed: selection.reversed,
1735                        goal: selection.goal,
1736                    });
1737            }
1738        }
1739
1740        for (buffer_id, buffer_state) in self.buffers.iter() {
1741            if !selections_by_buffer.contains_key(buffer_id) {
1742                buffer_state
1743                    .buffer
1744                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1745            }
1746        }
1747
1748        for (buffer_id, selections) in selections_by_buffer {
1749            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1750                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1751            });
1752        }
1753    }
1754
1755    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1756        for buffer in self.buffers.values() {
1757            buffer
1758                .buffer
1759                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1760        }
1761    }
1762
1763    #[instrument(skip_all)]
1764    fn merge_excerpt_ranges<'a>(
1765        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1766    ) -> Vec<ExcerptRange<Point>> {
1767        let mut sorted: Vec<_> = expanded_ranges.into_iter().collect();
1768        sorted.sort_by_key(|range| range.context.start);
1769        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1770        for range in sorted {
1771            if let Some(last_range) = merged_ranges.last_mut() {
1772                if last_range.context.end >= range.context.start
1773                    || last_range.context.end.row + 1 == range.context.start.row
1774                {
1775                    last_range.context.end = range.context.end.max(last_range.context.end);
1776                    continue;
1777                }
1778            }
1779            merged_ranges.push(range.clone());
1780        }
1781        merged_ranges
1782    }
1783
1784    pub fn clear(&mut self, cx: &mut Context<Self>) {
1785        self.sync_mut(cx);
1786        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1787        self.diffs.clear();
1788        let MultiBufferSnapshot {
1789            excerpts,
1790            diffs,
1791            diff_transforms: _,
1792            non_text_state_update_count: _,
1793            edit_count: _,
1794            is_dirty,
1795            has_deleted_file,
1796            has_conflict,
1797            has_inverted_diff,
1798            singleton: _,
1799            trailing_excerpt_update_count,
1800            all_diff_hunks_expanded: _,
1801            show_deleted_hunks: _,
1802            use_extended_diff_range: _,
1803            show_headers: _,
1804            path_keys: _,
1805            buffers,
1806        } = self.snapshot.get_mut();
1807        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1808        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1809        *excerpts = Default::default();
1810        *buffers = Default::default();
1811        *diffs = Default::default();
1812        *trailing_excerpt_update_count += 1;
1813        *is_dirty = false;
1814        *has_deleted_file = false;
1815        *has_conflict = false;
1816        *has_inverted_diff = false;
1817
1818        let edits = Self::sync_diff_transforms(
1819            self.snapshot.get_mut(),
1820            vec![Edit {
1821                old: start..prev_len,
1822                new: start..start,
1823            }],
1824            DiffChangeKind::BufferEdited,
1825        );
1826        if !edits.is_empty() {
1827            self.subscriptions.publish(edits);
1828        }
1829        cx.emit(Event::Edited {
1830            edited_buffer: None,
1831            is_local: true,
1832        });
1833        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1834        cx.notify();
1835    }
1836
1837    // If point is at the end of the buffer, the last excerpt is returned
1838    pub fn point_to_buffer_offset<T: ToOffset>(
1839        &self,
1840        point: T,
1841        cx: &App,
1842    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1843        let snapshot = self.read(cx);
1844        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1845        Some((
1846            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1847            offset,
1848        ))
1849    }
1850
1851    // If point is at the end of the buffer, the last excerpt is returned
1852    pub fn point_to_buffer_point<T: ToPoint>(
1853        &self,
1854        point: T,
1855        cx: &App,
1856    ) -> Option<(Entity<Buffer>, Point)> {
1857        let snapshot = self.read(cx);
1858        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1859        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1860    }
1861
1862    pub fn buffer_point_to_anchor(
1863        &self,
1864        // todo(lw): We shouldn't need this?
1865        buffer: &Entity<Buffer>,
1866        point: Point,
1867        cx: &App,
1868    ) -> Option<Anchor> {
1869        let mut found = None;
1870        let buffer_snapshot = buffer.read(cx).snapshot();
1871        let text_anchor = buffer_snapshot.anchor_after(&point);
1872        let snapshot = self.snapshot(cx);
1873        let path_key_index = snapshot.path_key_index_for_buffer(buffer_snapshot.remote_id())?;
1874        for excerpt in snapshot.excerpts_for_buffer(buffer_snapshot.remote_id()) {
1875            if excerpt
1876                .context
1877                .start
1878                .cmp(&text_anchor, &buffer_snapshot)
1879                .is_gt()
1880            {
1881                found = Some(Anchor::in_buffer(path_key_index, excerpt.context.start));
1882                break;
1883            } else if excerpt
1884                .context
1885                .end
1886                .cmp(&text_anchor, &buffer_snapshot)
1887                .is_ge()
1888            {
1889                found = Some(Anchor::in_buffer(path_key_index, text_anchor));
1890                break;
1891            }
1892            found = Some(Anchor::in_buffer(path_key_index, excerpt.context.end));
1893        }
1894
1895        found
1896    }
1897
1898    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1899        &self,
1900        anchors: Anchors,
1901        cx: &mut Context<Self>,
1902    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1903        let mut error = None;
1904        let mut futures = Vec::new();
1905        for anchor in anchors {
1906            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1907                if let Some(buffer) = self.buffers.get(&excerpt_anchor.text_anchor.buffer_id) {
1908                    buffer.buffer.update(cx, |buffer, _| {
1909                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1910                    });
1911                } else {
1912                    error = Some(anyhow!(
1913                        "buffer {:?} is not part of this multi-buffer",
1914                        excerpt_anchor.text_anchor.buffer_id
1915                    ));
1916                    break;
1917                }
1918            }
1919        }
1920        async move {
1921            if let Some(error) = error {
1922                Err(error)?;
1923            }
1924            for future in futures {
1925                future.await?;
1926            }
1927            Ok(())
1928        }
1929    }
1930
1931    pub fn text_anchor_for_position<T: ToOffset>(
1932        &self,
1933        position: T,
1934        cx: &App,
1935    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1936        let snapshot = self.read(cx);
1937        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1938        let buffer = self
1939            .buffers
1940            .get(&anchor.text_anchor.buffer_id)?
1941            .buffer
1942            .clone();
1943        Some((buffer, anchor.text_anchor()))
1944    }
1945
1946    fn on_buffer_event(
1947        &mut self,
1948        buffer: Entity<Buffer>,
1949        event: &language::BufferEvent,
1950        cx: &mut Context<Self>,
1951    ) {
1952        use language::BufferEvent;
1953        let buffer_id = buffer.read(cx).remote_id();
1954        cx.emit(match event {
1955            &BufferEvent::Edited { is_local } => Event::Edited {
1956                edited_buffer: Some(buffer),
1957                is_local,
1958            },
1959            BufferEvent::DirtyChanged => Event::DirtyChanged,
1960            BufferEvent::Saved => Event::Saved,
1961            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1962            BufferEvent::Reloaded => Event::Reloaded,
1963            BufferEvent::LanguageChanged(has_language) => {
1964                Event::LanguageChanged(buffer_id, *has_language)
1965            }
1966            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1967            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1968            BufferEvent::CapabilityChanged => {
1969                self.capability = buffer.read(cx).capability();
1970                return;
1971            }
1972            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1973        });
1974    }
1975
1976    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1977        let diff = diff.read(cx);
1978        let buffer_id = diff.buffer_id;
1979        let diff = DiffStateSnapshot {
1980            buffer_id,
1981            diff: diff.snapshot(cx),
1982            main_buffer: None,
1983        };
1984        self.snapshot.get_mut().diffs.insert_or_replace(diff, ());
1985    }
1986
1987    fn inverted_buffer_diff_language_changed(
1988        &mut self,
1989        diff: Entity<BufferDiff>,
1990        main_buffer: Entity<language::Buffer>,
1991        cx: &mut Context<Self>,
1992    ) {
1993        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
1994        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
1995        let diff = diff.read(cx);
1996        let diff = DiffStateSnapshot {
1997            buffer_id: base_text_buffer_id,
1998            diff: diff.snapshot(cx),
1999            main_buffer: Some(main_buffer_snapshot),
2000        };
2001        self.snapshot.get_mut().diffs.insert_or_replace(diff, ());
2002    }
2003
2004    fn buffer_diff_changed(
2005        &mut self,
2006        diff: Entity<BufferDiff>,
2007        range: Range<text::Anchor>,
2008        cx: &mut Context<Self>,
2009    ) {
2010        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2011            return;
2012        };
2013        let snapshot = self.sync_mut(cx);
2014
2015        let diff = diff.read(cx);
2016        let buffer_id = diff.buffer_id;
2017
2018        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2019            return;
2020        };
2021        let new_diff = DiffStateSnapshot {
2022            buffer_id,
2023            diff: diff.snapshot(cx),
2024            main_buffer: None,
2025        };
2026        let snapshot = self.snapshot.get_mut();
2027        let base_text_changed = find_diff_state(&snapshot.diffs, buffer_id)
2028            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2029        snapshot.diffs.insert_or_replace(new_diff, ());
2030
2031        let buffer = buffer.read(cx);
2032        let diff_change_range = range.to_offset(buffer);
2033
2034        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2035        let edits = Self::sync_diff_transforms(
2036            snapshot,
2037            excerpt_edits,
2038            DiffChangeKind::DiffUpdated {
2039                base_changed: base_text_changed,
2040            },
2041        );
2042        if !edits.is_empty() {
2043            self.subscriptions.publish(edits);
2044        }
2045        cx.emit(Event::Edited {
2046            edited_buffer: None,
2047            is_local: true,
2048        });
2049    }
2050
2051    fn inverted_buffer_diff_changed(
2052        &mut self,
2053        diff: Entity<BufferDiff>,
2054        main_buffer: Entity<language::Buffer>,
2055        diff_change_range: Option<Range<usize>>,
2056        cx: &mut Context<Self>,
2057    ) {
2058        let snapshot = self.sync_mut(cx);
2059
2060        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2061        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2062            return;
2063        };
2064
2065        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2066        let diff = diff.read(cx);
2067        let new_diff = DiffStateSnapshot {
2068            buffer_id: base_text_buffer_id,
2069            diff: diff.snapshot(cx),
2070            main_buffer: Some(main_buffer_snapshot),
2071        };
2072        let snapshot = self.snapshot.get_mut();
2073        snapshot.diffs.insert_or_replace(new_diff, ());
2074
2075        let Some(diff_change_range) = diff_change_range else {
2076            return;
2077        };
2078
2079        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2080        let edits = Self::sync_diff_transforms(
2081            snapshot,
2082            excerpt_edits,
2083            DiffChangeKind::DiffUpdated {
2084                // We don't read this field for inverted diffs.
2085                base_changed: false,
2086            },
2087        );
2088        if !edits.is_empty() {
2089            self.subscriptions.publish(edits);
2090        }
2091        cx.emit(Event::Edited {
2092            edited_buffer: None,
2093            is_local: true,
2094        });
2095    }
2096
2097    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2098        self.buffers.values().map(|state| state.buffer.clone())
2099    }
2100
2101    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2102        self.all_buffers_iter().collect()
2103    }
2104
2105    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2106        self.buffers
2107            .get(&buffer_id)
2108            .map(|state| state.buffer.clone())
2109    }
2110
2111    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2112        self.point_to_buffer_offset(point, cx)
2113            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2114    }
2115
2116    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2117        let snapshot = self.snapshot(cx);
2118        snapshot
2119            .excerpts
2120            .first()
2121            .and_then(|excerpt| self.buffer(excerpt.range.context.start.buffer_id))
2122            .map(|buffer| LanguageSettings::for_buffer(&buffer.read(cx), cx))
2123            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2124    }
2125
2126    pub fn language_settings_at<'a, T: ToOffset>(
2127        &'a self,
2128        point: T,
2129        cx: &'a App,
2130    ) -> Cow<'a, LanguageSettings> {
2131        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2132            LanguageSettings::for_buffer_at(buffer.read(cx), offset, cx)
2133        } else {
2134            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
2135        }
2136    }
2137
2138    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2139        self.buffers.values().for_each(|state| f(&state.buffer))
2140    }
2141
2142    pub fn explicit_title(&self) -> Option<&str> {
2143        self.title.as_deref()
2144    }
2145
2146    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2147        if let Some(title) = self.title.as_ref() {
2148            return title.into();
2149        }
2150
2151        if let Some(buffer) = self.as_singleton() {
2152            let buffer = buffer.read(cx);
2153
2154            if let Some(file) = buffer.file() {
2155                return file.file_name(cx).into();
2156            }
2157
2158            if let Some(title) = self.buffer_content_title(buffer) {
2159                return title;
2160            }
2161        };
2162
2163        "untitled".into()
2164    }
2165
2166    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2167        let mut is_leading_whitespace = true;
2168        let mut count = 0;
2169        let mut prev_was_space = false;
2170        let mut title = String::new();
2171
2172        for ch in buffer.snapshot().chars() {
2173            if is_leading_whitespace && ch.is_whitespace() {
2174                continue;
2175            }
2176
2177            is_leading_whitespace = false;
2178
2179            if ch == '\n' || count >= 40 {
2180                break;
2181            }
2182
2183            if ch.is_whitespace() {
2184                if !prev_was_space {
2185                    title.push(' ');
2186                    count += 1;
2187                    prev_was_space = true;
2188                }
2189            } else {
2190                title.push(ch);
2191                count += 1;
2192                prev_was_space = false;
2193            }
2194        }
2195
2196        let title = title.trim_end().to_string();
2197
2198        if title.is_empty() {
2199            return None;
2200        }
2201
2202        Some(title.into())
2203    }
2204
2205    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2206        self.title = Some(title);
2207        cx.notify();
2208    }
2209
2210    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2211    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2212        for buffer_state in self.buffers.values() {
2213            buffer_state
2214                .buffer
2215                .update(cx, |buffer, _cx| buffer.refresh_preview());
2216        }
2217    }
2218
2219    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2220    pub fn preserve_preview(&self, cx: &App) -> bool {
2221        self.buffers
2222            .values()
2223            .all(|state| state.buffer.read(cx).preserve_preview())
2224    }
2225
2226    #[cfg(any(test, feature = "test-support"))]
2227    pub fn is_parsing(&self, cx: &App) -> bool {
2228        self.as_singleton().unwrap().read(cx).is_parsing()
2229    }
2230
2231    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2232        let buffer_id = diff.read(cx).buffer_id;
2233
2234        if let Some(existing_diff) = self.diff_for(buffer_id)
2235            && diff.entity_id() == existing_diff.entity_id()
2236        {
2237            return;
2238        }
2239
2240        self.buffer_diff_changed(
2241            diff.clone(),
2242            text::Anchor::min_max_range_for_buffer(buffer_id),
2243            cx,
2244        );
2245        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2246    }
2247
2248    pub fn add_inverted_diff(
2249        &mut self,
2250        diff: Entity<BufferDiff>,
2251        main_buffer: Entity<language::Buffer>,
2252        cx: &mut Context<Self>,
2253    ) {
2254        let snapshot = diff.read(cx).base_text(cx);
2255        let base_text_buffer_id = snapshot.remote_id();
2256        let diff_change_range = 0..snapshot.len();
2257        self.snapshot.get_mut().has_inverted_diff = true;
2258        self.inverted_buffer_diff_changed(
2259            diff.clone(),
2260            main_buffer.clone(),
2261            Some(diff_change_range),
2262            cx,
2263        );
2264        self.diffs.insert(
2265            base_text_buffer_id,
2266            DiffState::new_inverted(diff, main_buffer, cx),
2267        );
2268    }
2269
2270    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2271        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2272    }
2273
2274    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2275        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2276    }
2277
2278    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2279        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2280    }
2281
2282    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2283        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2284        self.expand_or_collapse_diff_hunks(vec![Anchor::Min..Anchor::Max], true, cx);
2285    }
2286
2287    pub fn all_diff_hunks_expanded(&self) -> bool {
2288        self.snapshot.borrow().all_diff_hunks_expanded
2289    }
2290
2291    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2292        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2293        self.expand_or_collapse_diff_hunks(vec![Anchor::Min..Anchor::Max], false, cx);
2294    }
2295
2296    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2297        self.snapshot.get_mut().show_deleted_hunks = show;
2298
2299        self.sync_mut(cx);
2300
2301        let old_len = self.snapshot.borrow().len();
2302
2303        let ranges = std::iter::once((Point::zero()..Point::MAX, None));
2304        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2305
2306        let new_len = self.snapshot.borrow().len();
2307
2308        self.subscriptions.publish(vec![Edit {
2309            old: MultiBufferOffset(0)..old_len,
2310            new: MultiBufferOffset(0)..new_len,
2311        }]);
2312
2313        cx.emit(Event::DiffHunksToggled);
2314        cx.emit(Event::Edited {
2315            edited_buffer: None,
2316            is_local: true,
2317        });
2318    }
2319
2320    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2321        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2322    }
2323
2324    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2325        self.read(cx)
2326            .diff_hunks_in_range(Anchor::Min..Anchor::Max)
2327            .nth(1)
2328            .is_some()
2329    }
2330
2331    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2332        let snapshot = self.read(cx);
2333        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2334        let offset_range = range.to_offset(&snapshot);
2335        cursor.seek(&offset_range.start, Bias::Left);
2336        while let Some(item) = cursor.item() {
2337            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2338                break;
2339            }
2340            if item.hunk_info().is_some() {
2341                return true;
2342            }
2343            cursor.next();
2344        }
2345        false
2346    }
2347
2348    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2349        let snapshot = self.read(cx);
2350        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2351        for range in ranges {
2352            let range = range.to_point(&snapshot);
2353            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2354            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2355                .min(snapshot.len());
2356            cursor.seek(&start, Bias::Right);
2357            while let Some(item) = cursor.item() {
2358                if *cursor.start() >= end {
2359                    break;
2360                }
2361                if item.hunk_info().is_some() {
2362                    return true;
2363                }
2364                cursor.next();
2365            }
2366        }
2367        false
2368    }
2369
2370    pub fn expand_or_collapse_diff_hunks_inner(
2371        &mut self,
2372        ranges: impl IntoIterator<Item = (Range<Point>, Option<Anchor>)>,
2373        expand: bool,
2374        cx: &mut Context<Self>,
2375    ) -> Vec<Edit<MultiBufferOffset>> {
2376        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2377            return Vec::new();
2378        }
2379        self.sync_mut(cx);
2380        let mut snapshot = self.snapshot.get_mut();
2381        let mut excerpt_edits = Vec::new();
2382        let mut last_hunk_row = None;
2383        for (range, end_anchor) in ranges {
2384            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2385                if let Some(end_anchor) = &end_anchor
2386                    && let Some(hunk_end_anchor) =
2387                        snapshot.anchor_in_excerpt(diff_hunk.excerpt_range.context.end)
2388                    && hunk_end_anchor.cmp(end_anchor, snapshot).is_gt()
2389                {
2390                    continue;
2391                }
2392                let hunk_range = diff_hunk.multi_buffer_range;
2393                if let Some(excerpt_start_anchor) =
2394                    snapshot.anchor_in_excerpt(diff_hunk.excerpt_range.context.start)
2395                    && hunk_range.start.to_point(snapshot) < excerpt_start_anchor.to_point(snapshot)
2396                {
2397                    continue;
2398                }
2399                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2400                    continue;
2401                }
2402                let mut start = snapshot.excerpt_offset_for_anchor(&hunk_range.start);
2403                let mut end = snapshot.excerpt_offset_for_anchor(&hunk_range.end);
2404                if let Some(excerpt_end_anchor) =
2405                    snapshot.anchor_in_excerpt(diff_hunk.excerpt_range.context.end)
2406                {
2407                    let excerpt_end = snapshot.excerpt_offset_for_anchor(&excerpt_end_anchor);
2408                    start = start.min(excerpt_end);
2409                    end = end.min(excerpt_end);
2410                };
2411                last_hunk_row = Some(diff_hunk.row_range.start);
2412                excerpt_edits.push(text::Edit {
2413                    old: start..end,
2414                    new: start..end,
2415                });
2416            }
2417        }
2418
2419        Self::sync_diff_transforms(
2420            &mut snapshot,
2421            excerpt_edits,
2422            DiffChangeKind::ExpandOrCollapseHunks { expand },
2423        )
2424    }
2425
2426    pub fn expand_or_collapse_diff_hunks(
2427        &mut self,
2428        ranges: Vec<Range<Anchor>>,
2429        expand: bool,
2430        cx: &mut Context<Self>,
2431    ) {
2432        let snapshot = self.snapshot.borrow().clone();
2433        let ranges =
2434            ranges.iter().map(move |range| {
2435                let excerpt_end = snapshot.excerpt_containing(range.end..range.end).and_then(
2436                    |(_, excerpt_range)| snapshot.anchor_in_excerpt(excerpt_range.context.end),
2437                );
2438                let range = range.to_point(&snapshot);
2439                let mut peek_end = range.end;
2440                if range.end.row < snapshot.max_row().0 {
2441                    peek_end = Point::new(range.end.row + 1, 0);
2442                };
2443                (range.start..peek_end, excerpt_end)
2444            });
2445        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2446        if !edits.is_empty() {
2447            self.subscriptions.publish(edits);
2448        }
2449        cx.emit(Event::DiffHunksToggled);
2450        cx.emit(Event::Edited {
2451            edited_buffer: None,
2452            is_local: true,
2453        });
2454    }
2455
2456    #[ztracing::instrument(skip_all)]
2457    fn sync(&self, cx: &App) {
2458        let changed = self.buffer_changed_since_sync.replace(false);
2459        if !changed {
2460            return;
2461        }
2462        let edits = Self::sync_from_buffer_changes(
2463            &mut self.snapshot.borrow_mut(),
2464            &self.buffers,
2465            &self.diffs,
2466            cx,
2467        );
2468        if !edits.is_empty() {
2469            self.subscriptions.publish(edits);
2470        }
2471    }
2472
2473    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2474        let snapshot = self.snapshot.get_mut();
2475        let changed = self.buffer_changed_since_sync.replace(false);
2476        if !changed {
2477            return snapshot;
2478        }
2479        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2480
2481        if !edits.is_empty() {
2482            self.subscriptions.publish(edits);
2483        }
2484
2485        snapshot
2486    }
2487
2488    fn sync_from_buffer_changes(
2489        snapshot: &mut MultiBufferSnapshot,
2490        buffers: &BTreeMap<BufferId, BufferState>,
2491        diffs: &HashMap<BufferId, DiffState>,
2492        cx: &App,
2493    ) -> Vec<Edit<MultiBufferOffset>> {
2494        let MultiBufferSnapshot {
2495            excerpts,
2496            diffs: buffer_diff,
2497            buffers: buffer_snapshots,
2498            path_keys: _,
2499            diff_transforms: _,
2500            non_text_state_update_count,
2501            edit_count,
2502            is_dirty,
2503            has_deleted_file,
2504            has_conflict,
2505            has_inverted_diff: _,
2506            singleton: _,
2507            trailing_excerpt_update_count: _,
2508            all_diff_hunks_expanded: _,
2509            show_deleted_hunks: _,
2510            use_extended_diff_range: _,
2511            show_headers: _,
2512        } = snapshot;
2513        *is_dirty = false;
2514        *has_deleted_file = false;
2515        *has_conflict = false;
2516
2517        if !diffs.is_empty() {
2518            let mut diffs_to_add = Vec::new();
2519            for (id, diff) in diffs {
2520                if find_diff_state(buffer_diff, *id).is_none_or(|existing_diff| {
2521                    if existing_diff.main_buffer.is_none() {
2522                        return false;
2523                    }
2524                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2525                    base_text.remote_id() != existing_diff.base_text().remote_id()
2526                        || base_text
2527                            .version()
2528                            .changed_since(existing_diff.base_text().version())
2529                }) {
2530                    if diffs_to_add.capacity() == 0 {
2531                        diffs_to_add.reserve(diffs.len());
2532                    }
2533                    diffs_to_add.push(sum_tree::Edit::Insert(diff.snapshot(*id, cx)));
2534                }
2535            }
2536            buffer_diff.edit(diffs_to_add, ());
2537        }
2538
2539        let mut paths_to_edit = Vec::new();
2540        let mut non_text_state_updated = false;
2541        let mut edited = false;
2542        for buffer_state in buffers.values() {
2543            let buffer = buffer_state.buffer.read(cx);
2544            let last_snapshot = buffer_snapshots
2545                .get(&buffer.remote_id())
2546                .expect("each buffer should have a snapshot");
2547            let current_version = buffer.version();
2548            let non_text_state_update_count = buffer.non_text_state_update_count();
2549
2550            let buffer_edited =
2551                current_version.changed_since(last_snapshot.buffer_snapshot.version());
2552            let buffer_non_text_state_updated = non_text_state_update_count
2553                > last_snapshot.buffer_snapshot.non_text_state_update_count();
2554            if buffer_edited || buffer_non_text_state_updated {
2555                paths_to_edit.push((
2556                    last_snapshot.path_key.clone(),
2557                    last_snapshot.path_key_index,
2558                    buffer_state.buffer.clone(),
2559                    if buffer_edited {
2560                        Some(last_snapshot.buffer_snapshot.version().clone())
2561                    } else {
2562                        None
2563                    },
2564                ));
2565            }
2566
2567            edited |= buffer_edited;
2568            non_text_state_updated |= buffer_non_text_state_updated;
2569            *is_dirty |= buffer.is_dirty();
2570            *has_deleted_file |= buffer
2571                .file()
2572                .is_some_and(|file| file.disk_state().is_deleted());
2573            *has_conflict |= buffer.has_conflict();
2574        }
2575        if edited {
2576            *edit_count += 1;
2577        }
2578        if non_text_state_updated {
2579            *non_text_state_update_count += 1;
2580        }
2581
2582        paths_to_edit.sort_unstable_by_key(|(path, _, _, _)| path.clone());
2583
2584        let mut edits = Vec::new();
2585        let mut new_excerpts = SumTree::default();
2586        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2587
2588        for (path, path_key_index, buffer, prev_version) in paths_to_edit {
2589            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2590            let buffer = buffer.read(cx);
2591            let buffer_id = buffer.remote_id();
2592
2593            buffer_snapshots.insert(
2594                buffer_id,
2595                BufferStateSnapshot {
2596                    path_key: path.clone(),
2597                    path_key_index,
2598                    buffer_snapshot: buffer.snapshot(),
2599                },
2600            );
2601
2602            if let Some(prev_version) = &prev_version {
2603                while let Some(old_excerpt) = cursor.item()
2604                    && &old_excerpt.path_key == &path
2605                {
2606                    edits.extend(
2607                        buffer
2608                            .edits_since_in_range::<usize>(
2609                                prev_version,
2610                                old_excerpt.range.context.clone(),
2611                            )
2612                            .map(|edit| {
2613                                let excerpt_old_start = cursor.start().len();
2614                                let excerpt_new_start =
2615                                    ExcerptDimension(new_excerpts.summary().text.len);
2616                                let old_start = excerpt_old_start + edit.old.start;
2617                                let old_end = excerpt_old_start + edit.old.end;
2618                                let new_start = excerpt_new_start + edit.new.start;
2619                                let new_end = excerpt_new_start + edit.new.end;
2620                                Edit {
2621                                    old: old_start..old_end,
2622                                    new: new_start..new_end,
2623                                }
2624                            }),
2625                    );
2626
2627                    let excerpt = Excerpt::new(
2628                        old_excerpt.path_key.clone(),
2629                        old_excerpt.path_key_index,
2630                        &buffer.snapshot(),
2631                        old_excerpt.range.clone(),
2632                        old_excerpt.has_trailing_newline,
2633                    );
2634                    new_excerpts.push(excerpt, ());
2635                    cursor.next();
2636                }
2637            } else {
2638                new_excerpts.append(cursor.slice(&path, Bias::Right), ());
2639            };
2640        }
2641        new_excerpts.append(cursor.suffix(), ());
2642
2643        drop(cursor);
2644        *excerpts = new_excerpts;
2645
2646        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2647    }
2648
2649    fn sync_diff_transforms(
2650        snapshot: &mut MultiBufferSnapshot,
2651        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2652        change_kind: DiffChangeKind,
2653    ) -> Vec<Edit<MultiBufferOffset>> {
2654        if excerpt_edits.is_empty() {
2655            return vec![];
2656        }
2657
2658        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2659        let mut old_diff_transforms = snapshot
2660            .diff_transforms
2661            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2662        let mut new_diff_transforms = SumTree::default();
2663        let mut old_expanded_hunks = HashSet::default();
2664        let mut output_edits = Vec::new();
2665        let mut output_delta = 0_isize;
2666        let mut at_transform_boundary = true;
2667        let mut end_of_current_insert = None;
2668
2669        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2670        while let Some(edit) = excerpt_edits.next() {
2671            excerpts.seek_forward(&edit.new.start, Bias::Right);
2672            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2673                excerpts.prev();
2674            }
2675
2676            // Keep any transforms that are before the edit.
2677            if at_transform_boundary {
2678                at_transform_boundary = false;
2679                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2680                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2681                if let Some(transform) = old_diff_transforms.item()
2682                    && old_diff_transforms.end().0 == edit.old.start
2683                    && old_diff_transforms.start().0 < edit.old.start
2684                {
2685                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2686                    old_diff_transforms.next();
2687                }
2688            }
2689
2690            // Compute the start of the edit in output coordinates.
2691            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2692            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2693            let edit_new_start =
2694                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2695
2696            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2697                &edit,
2698                &mut excerpts,
2699                &mut old_diff_transforms,
2700                &mut new_diff_transforms,
2701                &mut end_of_current_insert,
2702                &mut old_expanded_hunks,
2703                snapshot,
2704                change_kind,
2705            );
2706
2707            // Compute the end of the edit in output coordinates.
2708            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2709            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2710            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2711            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2712            let output_edit = Edit {
2713                old: edit_old_start..edit_old_end,
2714                new: edit_new_start..edit_new_end,
2715            };
2716
2717            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2718            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2719            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2720                output_edits.push(output_edit);
2721            }
2722
2723            // If this is the last edit that intersects the current diff transform,
2724            // then recreate the content up to the end of this transform, to prepare
2725            // for reusing additional slices of the old transforms.
2726            if excerpt_edits
2727                .peek()
2728                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2729            {
2730                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2731                    && match old_diff_transforms.item() {
2732                        Some(DiffTransform::BufferContent {
2733                            inserted_hunk_info: Some(hunk),
2734                            ..
2735                        }) => excerpts.item().is_some_and(|excerpt| {
2736                            if let Some(diff) = find_diff_state(&snapshot.diffs, excerpt.buffer_id)
2737                                && diff.main_buffer.is_some()
2738                            {
2739                                return true;
2740                            }
2741                            hunk.hunk_start_anchor
2742                                .is_valid(&excerpt.buffer_snapshot(&snapshot))
2743                        }),
2744                        _ => true,
2745                    };
2746
2747                let mut excerpt_offset = edit.new.end;
2748                if !keep_next_old_transform {
2749                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2750                    old_diff_transforms.next();
2751                }
2752
2753                old_expanded_hunks.clear();
2754                Self::push_buffer_content_transform(
2755                    snapshot,
2756                    &mut new_diff_transforms,
2757                    excerpt_offset,
2758                    end_of_current_insert,
2759                );
2760                at_transform_boundary = true;
2761            }
2762        }
2763
2764        // Keep any transforms that are after the last edit.
2765        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2766
2767        // Ensure there's always at least one buffer content transform.
2768        if new_diff_transforms.is_empty() {
2769            new_diff_transforms.push(
2770                DiffTransform::BufferContent {
2771                    summary: Default::default(),
2772                    inserted_hunk_info: None,
2773                },
2774                (),
2775            );
2776        }
2777
2778        drop(old_diff_transforms);
2779        drop(excerpts);
2780        snapshot.diff_transforms = new_diff_transforms;
2781        snapshot.edit_count += 1;
2782
2783        #[cfg(any(test, feature = "test-support"))]
2784        snapshot.check_invariants();
2785        output_edits
2786    }
2787
2788    fn recompute_diff_transforms_for_edit(
2789        edit: &Edit<ExcerptOffset>,
2790        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2791        old_diff_transforms: &mut Cursor<
2792            DiffTransform,
2793            Dimensions<ExcerptOffset, MultiBufferOffset>,
2794        >,
2795        new_diff_transforms: &mut SumTree<DiffTransform>,
2796        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2797        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2798        snapshot: &MultiBufferSnapshot,
2799        change_kind: DiffChangeKind,
2800    ) -> bool {
2801        log::trace!(
2802            "recomputing diff transform for edit {:?} => {:?}",
2803            edit.old.start..edit.old.end,
2804            edit.new.start..edit.new.end
2805        );
2806
2807        // Record which hunks were previously expanded.
2808        while let Some(item) = old_diff_transforms.item() {
2809            if let Some(hunk_info) = item.hunk_info() {
2810                log::trace!(
2811                    "previously expanded hunk at {:?}",
2812                    old_diff_transforms.start()
2813                );
2814                old_expanded_hunks.insert(hunk_info);
2815            }
2816            if old_diff_transforms.end().0 > edit.old.end {
2817                break;
2818            }
2819            old_diff_transforms.next();
2820        }
2821
2822        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2823        // For inverted diffs, hunks are always shown, so we can't skip this.
2824        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2825        if old_expanded_hunks.is_empty()
2826            && change_kind == DiffChangeKind::BufferEdited
2827            && !all_diff_hunks_expanded
2828            && !snapshot.has_inverted_diff
2829        {
2830            return false;
2831        }
2832
2833        // Visit each excerpt that intersects the edit.
2834        let mut did_expand_hunks = false;
2835        while let Some(excerpt) = excerpts.item() {
2836            // Recompute the expanded hunks in the portion of the excerpt that
2837            // intersects the edit.
2838            if let Some(diff) = find_diff_state(&snapshot.diffs, excerpt.buffer_id) {
2839                let buffer_snapshot = &excerpt.buffer_snapshot(&snapshot);
2840                let excerpt_start = *excerpts.start();
2841                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2842                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer_snapshot);
2843                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2844                let edit_buffer_start =
2845                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2846                let edit_buffer_end =
2847                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2848                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2849
2850                if let Some(main_buffer) = &diff.main_buffer {
2851                    for hunk in diff.hunks_intersecting_base_text_range(
2852                        edit_buffer_start..edit_buffer_end,
2853                        main_buffer,
2854                    ) {
2855                        did_expand_hunks = true;
2856                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2857                        if hunk_buffer_range.start < excerpt_buffer_start {
2858                            log::trace!("skipping hunk that starts before excerpt");
2859                            continue;
2860                        }
2861                        let hunk_excerpt_start = excerpt_start
2862                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2863                        let hunk_excerpt_end = excerpt_end
2864                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2865                        Self::push_buffer_content_transform(
2866                            snapshot,
2867                            new_diff_transforms,
2868                            hunk_excerpt_start,
2869                            *end_of_current_insert,
2870                        );
2871                        if !hunk_buffer_range.is_empty() {
2872                            let hunk_info = DiffTransformHunkInfo {
2873                                buffer_id: buffer_snapshot.remote_id(),
2874                                hunk_start_anchor: hunk.buffer_range.start,
2875                                hunk_secondary_status: hunk.secondary_status,
2876                                excerpt_end: excerpt.end_anchor(),
2877                                is_logically_deleted: true,
2878                            };
2879                            *end_of_current_insert =
2880                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2881                        }
2882                    }
2883                } else {
2884                    let edit_anchor_range = buffer_snapshot.anchor_before(edit_buffer_start)
2885                        ..buffer_snapshot.anchor_after(edit_buffer_end);
2886                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer_snapshot) {
2887                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2888                            continue;
2889                        }
2890
2891                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer_snapshot);
2892                        if hunk_buffer_range.start < excerpt_buffer_start {
2893                            log::trace!("skipping hunk that starts before excerpt");
2894                            continue;
2895                        }
2896
2897                        let hunk_info = DiffTransformHunkInfo {
2898                            buffer_id: buffer_snapshot.remote_id(),
2899                            hunk_start_anchor: hunk.buffer_range.start,
2900                            hunk_secondary_status: hunk.secondary_status,
2901                            excerpt_end: excerpt.end_anchor(),
2902                            is_logically_deleted: false,
2903                        };
2904
2905                        let hunk_excerpt_start = excerpt_start
2906                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2907                        let hunk_excerpt_end = excerpt_end
2908                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2909
2910                        Self::push_buffer_content_transform(
2911                            snapshot,
2912                            new_diff_transforms,
2913                            hunk_excerpt_start,
2914                            *end_of_current_insert,
2915                        );
2916
2917                        // For every existing hunk, determine if it was previously expanded
2918                        // and if it should currently be expanded.
2919                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2920                        let should_expand_hunk = match &change_kind {
2921                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2922                                was_previously_expanded || all_diff_hunks_expanded
2923                            }
2924                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2925                                let intersects = hunk_buffer_range.is_empty()
2926                                    || (hunk_buffer_range.end > edit_buffer_start);
2927                                if *expand {
2928                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2929                                } else {
2930                                    !intersects
2931                                        && (was_previously_expanded || all_diff_hunks_expanded)
2932                                }
2933                            }
2934                            _ => was_previously_expanded || all_diff_hunks_expanded,
2935                        };
2936
2937                        if should_expand_hunk {
2938                            did_expand_hunks = true;
2939                            log::trace!(
2940                                "expanding hunk {:?}",
2941                                hunk_excerpt_start..hunk_excerpt_end,
2942                            );
2943
2944                            if !hunk.diff_base_byte_range.is_empty()
2945                                && hunk_buffer_range.start >= edit_buffer_start
2946                                && hunk_buffer_range.start <= excerpt_buffer_end
2947                                && snapshot.show_deleted_hunks
2948                            {
2949                                let base_text = diff.base_text();
2950                                let mut text_cursor =
2951                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2952                                let mut base_text_summary = text_cursor
2953                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2954
2955                                let mut has_trailing_newline = false;
2956                                if base_text_summary.last_line_chars > 0 {
2957                                    base_text_summary += TextSummary::newline();
2958                                    has_trailing_newline = true;
2959                                }
2960
2961                                new_diff_transforms.push(
2962                                    DiffTransform::DeletedHunk {
2963                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
2964                                        summary: base_text_summary,
2965                                        buffer_id: buffer_snapshot.remote_id(),
2966                                        hunk_info,
2967                                        has_trailing_newline,
2968                                    },
2969                                    (),
2970                                );
2971                            }
2972
2973                            if !hunk_buffer_range.is_empty() {
2974                                *end_of_current_insert =
2975                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2976                            }
2977                        }
2978                    }
2979                }
2980            }
2981
2982            if excerpts.end() <= edit.new.end {
2983                excerpts.next();
2984            } else {
2985                break;
2986            }
2987        }
2988
2989        did_expand_hunks || !old_expanded_hunks.is_empty()
2990    }
2991
2992    fn append_diff_transforms(
2993        new_transforms: &mut SumTree<DiffTransform>,
2994        subtree: SumTree<DiffTransform>,
2995    ) {
2996        if let Some(DiffTransform::BufferContent {
2997            inserted_hunk_info,
2998            summary,
2999        }) = subtree.first()
3000            && Self::extend_last_buffer_content_transform(
3001                new_transforms,
3002                *inserted_hunk_info,
3003                *summary,
3004            )
3005        {
3006            let mut cursor = subtree.cursor::<()>(());
3007            cursor.next();
3008            cursor.next();
3009            new_transforms.append(cursor.suffix(), ());
3010            return;
3011        }
3012        new_transforms.append(subtree, ());
3013    }
3014
3015    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3016        if let DiffTransform::BufferContent {
3017            inserted_hunk_info: inserted_hunk_anchor,
3018            summary,
3019        } = transform
3020            && Self::extend_last_buffer_content_transform(
3021                new_transforms,
3022                inserted_hunk_anchor,
3023                summary,
3024            )
3025        {
3026            return;
3027        }
3028        new_transforms.push(transform, ());
3029    }
3030
3031    fn push_buffer_content_transform(
3032        old_snapshot: &MultiBufferSnapshot,
3033        new_transforms: &mut SumTree<DiffTransform>,
3034        end_offset: ExcerptOffset,
3035        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3036    ) {
3037        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3038            (end_offset.min(insertion_end_offset), Some(hunk_info))
3039        });
3040        let unchanged_region = [(end_offset, None)];
3041
3042        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3043        {
3044            let start_offset = new_transforms.summary().excerpt_len();
3045            if end_offset <= start_offset {
3046                continue;
3047            }
3048            let summary_to_add = old_snapshot
3049                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3050
3051            if !Self::extend_last_buffer_content_transform(
3052                new_transforms,
3053                inserted_hunk_info,
3054                summary_to_add,
3055            ) {
3056                new_transforms.push(
3057                    DiffTransform::BufferContent {
3058                        summary: summary_to_add,
3059                        inserted_hunk_info,
3060                    },
3061                    (),
3062                )
3063            }
3064        }
3065    }
3066
3067    fn extend_last_buffer_content_transform(
3068        new_transforms: &mut SumTree<DiffTransform>,
3069        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3070        summary_to_add: MBTextSummary,
3071    ) -> bool {
3072        let mut did_extend = false;
3073        new_transforms.update_last(
3074            |last_transform| {
3075                if let DiffTransform::BufferContent {
3076                    summary,
3077                    inserted_hunk_info: inserted_hunk_anchor,
3078                } = last_transform
3079                    && *inserted_hunk_anchor == new_inserted_hunk_info
3080                {
3081                    *summary += summary_to_add;
3082                    did_extend = true;
3083                }
3084            },
3085            (),
3086        );
3087        did_extend
3088    }
3089
3090    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3091        let snapshot = self.snapshot(cx);
3092        let excerpt_end = snapshot
3093            .excerpt_containing(range.end..range.end)
3094            .and_then(|(_, excerpt_range)| snapshot.anchor_in_excerpt(excerpt_range.context.end));
3095        let point_range = range.to_point(&snapshot);
3096        let expand = !self.single_hunk_is_expanded(range, cx);
3097        let edits =
3098            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3099        if !edits.is_empty() {
3100            self.subscriptions.publish(edits);
3101        }
3102        cx.emit(Event::DiffHunksToggled);
3103        cx.emit(Event::Edited {
3104            edited_buffer: None,
3105            is_local: true,
3106        });
3107    }
3108}
3109
3110fn build_excerpt_ranges(
3111    ranges: impl IntoIterator<Item = Range<Point>>,
3112    context_line_count: u32,
3113    buffer_snapshot: &BufferSnapshot,
3114) -> Vec<ExcerptRange<Point>> {
3115    ranges
3116        .into_iter()
3117        .map(|range| {
3118            let start_row = range.start.row.saturating_sub(context_line_count);
3119            let start = Point::new(start_row, 0);
3120            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3121            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3122            ExcerptRange {
3123                context: start..end,
3124                primary: range,
3125            }
3126        })
3127        .collect()
3128}
3129
3130#[cfg(any(test, feature = "test-support"))]
3131impl MultiBuffer {
3132    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3133        let buffer = cx.new(|cx| Buffer::local(text, cx));
3134        cx.new(|cx| Self::singleton(buffer, cx))
3135    }
3136
3137    pub fn build_multi<const COUNT: usize>(
3138        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3139        cx: &mut gpui::App,
3140    ) -> Entity<Self> {
3141        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3142        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3143            let buffer = cx.new(|cx| Buffer::local(text, cx));
3144            let snapshot = buffer.read(cx).snapshot();
3145            let excerpt_ranges = ranges
3146                .into_iter()
3147                .map(ExcerptRange::new)
3148                .collect::<Vec<_>>();
3149            multi.update(cx, |multi, cx| {
3150                multi.set_excerpt_ranges_for_path(
3151                    PathKey::sorted(ix as u64),
3152                    buffer,
3153                    &snapshot,
3154                    excerpt_ranges,
3155                    cx,
3156                )
3157            });
3158        }
3159
3160        multi
3161    }
3162
3163    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3164        cx.new(|cx| Self::singleton(buffer, cx))
3165    }
3166
3167    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3168        cx.new(|cx| {
3169            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3170            let mutation_count = rng.random_range(1..=5);
3171            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3172            multibuffer
3173        })
3174    }
3175
3176    pub fn randomly_edit(
3177        &mut self,
3178        rng: &mut impl rand::Rng,
3179        edit_count: usize,
3180        cx: &mut Context<Self>,
3181    ) {
3182        use util::RandomCharIter;
3183
3184        let snapshot = self.read(cx);
3185        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3186        let mut last_end = None;
3187        for _ in 0..edit_count {
3188            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3189                break;
3190            }
3191
3192            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3193            let end =
3194                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3195            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3196            last_end = Some(end);
3197
3198            let mut range = start..end;
3199            if rng.random_bool(0.2) {
3200                mem::swap(&mut range.start, &mut range.end);
3201            }
3202
3203            let new_text_len = rng.random_range(0..10);
3204            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3205
3206            edits.push((range, new_text.into()));
3207        }
3208        log::info!("mutating multi-buffer with {:?}", edits);
3209        drop(snapshot);
3210
3211        self.edit(edits, None, cx);
3212    }
3213
3214    pub fn randomly_edit_excerpts(
3215        &mut self,
3216        rng: &mut impl rand::Rng,
3217        mutation_count: usize,
3218        cx: &mut Context<Self>,
3219    ) {
3220        use rand::prelude::*;
3221        use std::env;
3222        use util::RandomCharIter;
3223
3224        let max_buffers = env::var("MAX_BUFFERS")
3225            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3226            .unwrap_or(5);
3227
3228        let mut buffers = Vec::new();
3229        for _ in 0..mutation_count {
3230            let snapshot = self.snapshot(cx);
3231            let buffer_ids = snapshot.all_buffer_ids().collect::<Vec<_>>();
3232            if buffer_ids.is_empty() || (rng.random() && buffer_ids.len() < max_buffers) {
3233                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3234                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3235                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3236                    let buffer = buffers.last().unwrap().read(cx);
3237                    log::info!(
3238                        "Creating new buffer {} with text: {:?}",
3239                        buffer.remote_id(),
3240                        buffer.text()
3241                    );
3242                    buffers.last().unwrap().clone()
3243                } else {
3244                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3245                };
3246
3247                let buffer = buffer_handle.read(cx);
3248                let buffer_text = buffer.text();
3249                let buffer_snapshot = buffer.snapshot();
3250                let mut next_min_start_ix = 0;
3251                let ranges = (0..rng.random_range(0..5))
3252                    .filter_map(|_| {
3253                        if next_min_start_ix >= buffer.len() {
3254                            return None;
3255                        }
3256                        let end_ix = buffer.clip_offset(
3257                            rng.random_range(next_min_start_ix..=buffer.len()),
3258                            Bias::Right,
3259                        );
3260                        let start_ix = buffer
3261                            .clip_offset(rng.random_range(next_min_start_ix..=end_ix), Bias::Left);
3262                        next_min_start_ix = buffer.text().ceil_char_boundary(end_ix + 1);
3263                        Some(ExcerptRange::new(start_ix..end_ix))
3264                    })
3265                    .collect::<Vec<_>>();
3266                log::info!(
3267                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3268                    buffer_handle.read(cx).remote_id(),
3269                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3270                    ranges
3271                        .iter()
3272                        .map(|r| &buffer_text[r.context.clone()])
3273                        .collect::<Vec<_>>()
3274                );
3275
3276                let path_key = PathKey::for_buffer(&buffer_handle, cx);
3277                self.set_merged_excerpt_ranges_for_path(
3278                    path_key.clone(),
3279                    buffer_handle,
3280                    &buffer_snapshot,
3281                    ranges,
3282                    cx,
3283                );
3284                log::info!("Inserted with path_key: {:?}", path_key);
3285            } else {
3286                let path_key = self
3287                    .snapshot
3288                    .borrow()
3289                    .buffers
3290                    .get(&buffer_ids.choose(rng).unwrap())
3291                    .unwrap()
3292                    .path_key
3293                    .clone();
3294                log::info!("Removing excerpts {:?}", path_key);
3295                self.remove_excerpts(path_key, cx);
3296            }
3297        }
3298    }
3299
3300    pub fn randomly_mutate(
3301        &mut self,
3302        rng: &mut impl rand::Rng,
3303        mutation_count: usize,
3304        cx: &mut Context<Self>,
3305    ) {
3306        use rand::prelude::*;
3307
3308        if rng.random_bool(0.7) || self.singleton {
3309            let buffer = self
3310                .buffers
3311                .values()
3312                .choose(rng)
3313                .map(|state| state.buffer.clone());
3314
3315            if let Some(buffer) = buffer {
3316                buffer.update(cx, |buffer, cx| {
3317                    if rng.random() {
3318                        buffer.randomly_edit(rng, mutation_count, cx);
3319                    } else {
3320                        buffer.randomly_undo_redo(rng, cx);
3321                    }
3322                });
3323            } else {
3324                self.randomly_edit(rng, mutation_count, cx);
3325            }
3326        } else {
3327            self.randomly_edit_excerpts(rng, mutation_count, cx);
3328        }
3329
3330        self.check_invariants(cx);
3331    }
3332
3333    fn check_invariants(&self, cx: &App) {
3334        self.read(cx).check_invariants();
3335    }
3336}
3337
3338impl EventEmitter<Event> for MultiBuffer {}
3339
3340impl MultiBufferSnapshot {
3341    pub fn text(&self) -> String {
3342        self.chunks(
3343            MultiBufferOffset::ZERO..self.len(),
3344            LanguageAwareStyling {
3345                tree_sitter: false,
3346                diagnostics: false,
3347            },
3348        )
3349        .map(|chunk| chunk.text)
3350        .collect()
3351    }
3352
3353    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3354        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3355            .flat_map(|c| c.chars().rev())
3356    }
3357
3358    fn reversed_chunks_in_range(
3359        &self,
3360        range: Range<MultiBufferOffset>,
3361    ) -> ReversedMultiBufferChunks<'_> {
3362        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3363        cursor.seek(&range.end);
3364        let current_chunks = cursor.region().as_ref().map(|region| {
3365            let start_overshoot = range.start.saturating_sub(region.range.start);
3366            let end_overshoot = range.end - region.range.start;
3367            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3368            let start = region.buffer_range.start + start_overshoot;
3369            region.buffer.reversed_chunks_in_range(start..end)
3370        });
3371        ReversedMultiBufferChunks {
3372            cursor,
3373            current_chunks,
3374            start: range.start,
3375            offset: range.end,
3376        }
3377    }
3378
3379    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3380        let offset = position.to_offset(self);
3381        self.text_for_range(offset..self.len())
3382            .flat_map(|chunk| chunk.chars())
3383    }
3384
3385    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3386        self.chunks(
3387            range,
3388            LanguageAwareStyling {
3389                tree_sitter: false,
3390                diagnostics: false,
3391            },
3392        )
3393        .map(|chunk| chunk.text)
3394    }
3395
3396    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3397        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3398            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3399    }
3400
3401    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3402    where
3403        T: ToOffset,
3404    {
3405        let position = position.to_offset(self);
3406        position == self.clip_offset(position, Bias::Left)
3407            && self
3408                .bytes_in_range(position..self.len())
3409                .flatten()
3410                .copied()
3411                .take(needle.len())
3412                .eq(needle.bytes())
3413    }
3414
3415    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3416        self.diff_hunks_in_range(Anchor::Min..Anchor::Max)
3417    }
3418
3419    pub fn diff_hunks_in_range<T: ToPoint>(
3420        &self,
3421        range: Range<T>,
3422    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3423        let query_range = range.start.to_point(self)..range.end.to_point(self);
3424        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3425            let diff = self.diff_state(buffer.remote_id())?;
3426            let iter = if let Some(main_buffer) = &diff.main_buffer {
3427                let buffer_start = buffer.point_to_offset(buffer_range.start);
3428                let buffer_end = buffer.point_to_offset(buffer_range.end);
3429                itertools::Either::Left(
3430                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3431                        .map(move |hunk| (hunk, buffer, true)),
3432                )
3433            } else {
3434                let buffer_start = buffer.anchor_before(buffer_range.start);
3435                let buffer_end = buffer.anchor_after(buffer_range.end);
3436                itertools::Either::Right(
3437                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3438                        .map(move |hunk| (hunk, buffer, false)),
3439                )
3440            };
3441            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3442                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3443                    return None;
3444                }
3445                let range = if is_inverted {
3446                    hunk.diff_base_byte_range.to_point(&buffer)
3447                } else {
3448                    hunk.range.clone()
3449                };
3450                Some((range, (hunk, is_inverted)))
3451            }))
3452        })
3453        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3454            let buffer_snapshot = excerpt.buffer_snapshot(self);
3455            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3456            {
3457                return None;
3458            }
3459            let end_row = if range.end.column == 0 {
3460                range.end.row
3461            } else {
3462                range.end.row + 1
3463            };
3464
3465            let word_diffs =
3466                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3467                    .then(|| {
3468                        let mut word_diffs = Vec::new();
3469
3470                        if self.show_deleted_hunks || is_inverted {
3471                            let hunk_start_offset = if is_inverted {
3472                                Anchor::in_buffer(
3473                                    excerpt.path_key_index,
3474                                    buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start),
3475                                )
3476                                .to_offset(self)
3477                            } else {
3478                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3479                                    .to_offset(self)
3480                            };
3481
3482                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3483                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3484                            }));
3485                        }
3486
3487                        if !is_inverted {
3488                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3489                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3490                                    .to_offset(self)
3491                            }));
3492                        }
3493                        word_diffs
3494                    })
3495                    .unwrap_or_default();
3496
3497            let buffer_range = if is_inverted {
3498                buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start)
3499                    ..buffer_snapshot.anchor_before(hunk.diff_base_byte_range.end)
3500            } else {
3501                hunk.buffer_range.clone()
3502            };
3503            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3504                DiffHunkStatusKind::Deleted
3505            } else if hunk.diff_base_byte_range.is_empty() {
3506                DiffHunkStatusKind::Added
3507            } else {
3508                DiffHunkStatusKind::Modified
3509            };
3510            let multi_buffer_range =
3511                Anchor::range_in_buffer(excerpt.path_key_index, buffer_range.clone());
3512            Some(MultiBufferDiffHunk {
3513                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3514                buffer_id: buffer_snapshot.remote_id(),
3515                buffer_range,
3516                word_diffs,
3517                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3518                    ..BufferOffset(hunk.diff_base_byte_range.end),
3519                status: DiffHunkStatus {
3520                    kind: status_kind,
3521                    secondary: hunk.secondary_status,
3522                },
3523                excerpt_range: excerpt.range.clone(),
3524                multi_buffer_range,
3525            })
3526        })
3527    }
3528
3529    fn excerpts_for_range<T: ToOffset>(
3530        &self,
3531        range: Range<T>,
3532    ) -> impl Iterator<Item = &Excerpt> + '_ {
3533        let range = range.start.to_offset(self)..range.end.to_offset(self);
3534        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3535        cursor.seek(&range.start);
3536        std::iter::from_fn(move || {
3537            let region = cursor.region()?;
3538            if region.range.start > range.end
3539                || region.range.start == range.end && region.range.start > range.start
3540            {
3541                return None;
3542            }
3543            let excerpt = region.excerpt;
3544            cursor.next_excerpt_forwards();
3545            Some(excerpt)
3546        })
3547    }
3548
3549    pub fn buffer_ids_for_range<T: ToOffset>(
3550        &self,
3551        range: Range<T>,
3552    ) -> impl Iterator<Item = BufferId> + '_ {
3553        self.excerpts_for_range(range)
3554            .map(|excerpt| excerpt.buffer_snapshot(self).remote_id())
3555    }
3556
3557    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3558    ///
3559    /// The passed in anchors must be ordered.
3560    pub fn text_anchors_to_visible_anchors(
3561        &self,
3562        anchors: impl IntoIterator<Item = text::Anchor>,
3563    ) -> Vec<Option<Anchor>> {
3564        let anchors = anchors.into_iter();
3565        let mut result = Vec::with_capacity(anchors.size_hint().0);
3566        let mut anchors = anchors.peekable();
3567        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3568        'anchors: while let Some(anchor) = anchors.peek() {
3569            let buffer_id = anchor.buffer_id;
3570            let mut same_buffer_anchors = anchors.peeking_take_while(|a| a.buffer_id == buffer_id);
3571
3572            if let Some(buffer) = self.buffers.get(&buffer_id) {
3573                let path = &buffer.path_key;
3574                let Some(mut next) = same_buffer_anchors.next() else {
3575                    continue 'anchors;
3576                };
3577                cursor.seek_forward(path, Bias::Left);
3578                'excerpts: loop {
3579                    let Some(excerpt) = cursor.item() else {
3580                        break;
3581                    };
3582                    if excerpt.path_key != *path {
3583                        break;
3584                    }
3585                    let buffer_snapshot = excerpt.buffer_snapshot(self);
3586
3587                    loop {
3588                        // anchor is before the first excerpt
3589                        if excerpt
3590                            .range
3591                            .context
3592                            .start
3593                            .cmp(&next, &buffer_snapshot)
3594                            .is_gt()
3595                        {
3596                            // so we skip it and try the next anchor
3597                            result.push(None);
3598                            match same_buffer_anchors.next() {
3599                                Some(anchor) => next = anchor,
3600                                None => continue 'anchors,
3601                            }
3602                        // anchor is within the excerpt
3603                        } else if excerpt
3604                            .range
3605                            .context
3606                            .end
3607                            .cmp(&next, &buffer_snapshot)
3608                            .is_ge()
3609                        {
3610                            // record it and all following anchors that are within
3611                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3612                            result.extend(
3613                                same_buffer_anchors
3614                                    .peeking_take_while(|a| {
3615                                        excerpt.range.context.end.cmp(a, &buffer_snapshot).is_ge()
3616                                    })
3617                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3618                            );
3619                            match same_buffer_anchors.next() {
3620                                Some(anchor) => next = anchor,
3621                                None => continue 'anchors,
3622                            }
3623                        // anchor is after the excerpt, try the next one
3624                        } else {
3625                            cursor.next();
3626                            continue 'excerpts;
3627                        }
3628                    }
3629                }
3630                // account for `next`
3631                result.push(None);
3632            }
3633            result.extend(same_buffer_anchors.map(|_| None));
3634        }
3635
3636        result
3637    }
3638
3639    pub fn range_to_buffer_ranges<T: ToOffset>(
3640        &self,
3641        range: Range<T>,
3642    ) -> Vec<(
3643        BufferSnapshot,
3644        Range<BufferOffset>,
3645        ExcerptRange<text::Anchor>,
3646    )> {
3647        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3648        let start = range.start.to_offset(self);
3649        let end = range.end.to_offset(self);
3650        cursor.seek(&start);
3651
3652        let mut result: Vec<(
3653            BufferSnapshot,
3654            Range<BufferOffset>,
3655            ExcerptRange<text::Anchor>,
3656        )> = Vec::new();
3657        while let Some(region) = cursor.region() {
3658            if region.range.start >= end {
3659                break;
3660            }
3661            if region.is_main_buffer {
3662                let start_overshoot = start.saturating_sub(region.range.start);
3663                let end_offset = end;
3664                let end_overshoot = end_offset.saturating_sub(region.range.start);
3665                let start = region
3666                    .buffer_range
3667                    .end
3668                    .min(region.buffer_range.start + start_overshoot);
3669                let end = region
3670                    .buffer_range
3671                    .end
3672                    .min(region.buffer_range.start + end_overshoot);
3673                let excerpt_range = region.excerpt.range.clone();
3674                if let Some(prev) =
3675                    result
3676                        .last_mut()
3677                        .filter(|(prev_buffer, prev_range, prev_excerpt)| {
3678                            prev_buffer.remote_id() == region.buffer.remote_id()
3679                                && prev_range.end == start
3680                                && prev_excerpt.context.start == excerpt_range.context.start
3681                        })
3682                {
3683                    prev.1.end = end;
3684                } else {
3685                    result.push((region.buffer.clone(), start..end, excerpt_range));
3686                }
3687            }
3688            cursor.next();
3689        }
3690
3691        if let Some(excerpt) = cursor.excerpt()
3692            && excerpt.text_summary.len == 0
3693            && end == self.len()
3694        {
3695            let buffer_snapshot = excerpt.buffer_snapshot(self);
3696
3697            let buffer_offset =
3698                BufferOffset(excerpt.range.context.start.to_offset(buffer_snapshot));
3699            let excerpt_range = excerpt.range.clone();
3700            if result
3701                .last_mut()
3702                .is_none_or(|(prev_buffer, prev_range, prev_excerpt)| {
3703                    prev_buffer.remote_id() != buffer_snapshot.remote_id()
3704                        || prev_range.end != buffer_offset
3705                        || prev_excerpt.context.start != excerpt_range.context.start
3706                })
3707            {
3708                result.push((
3709                    buffer_snapshot.clone(),
3710                    buffer_offset..buffer_offset,
3711                    excerpt_range,
3712                ));
3713            }
3714        }
3715
3716        result
3717    }
3718
3719    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3720        &self,
3721        range: Range<T>,
3722    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, Option<Anchor>)> + '_ {
3723        let start = range.start.to_offset(self);
3724        let end = range.end.to_offset(self);
3725
3726        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3727        cursor.seek(&start);
3728
3729        std::iter::from_fn(move || {
3730            let region = cursor.region()?;
3731            if region.range.start > end {
3732                return None;
3733            }
3734            let start_overshoot = start.saturating_sub(region.range.start);
3735            let end_overshoot = end.saturating_sub(region.range.start);
3736            let start = region
3737                .buffer_range
3738                .end
3739                .min(region.buffer_range.start + start_overshoot);
3740            let end = region
3741                .buffer_range
3742                .end
3743                .min(region.buffer_range.start + end_overshoot);
3744
3745            let deleted_hunk_anchor = if region.is_main_buffer {
3746                None
3747            } else {
3748                Some(self.anchor_before(region.range.start))
3749            };
3750            let result = (region.buffer, start..end, deleted_hunk_anchor);
3751            cursor.next();
3752            Some(result)
3753        })
3754    }
3755
3756    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3757    /// coordinates.
3758    ///
3759    /// The given callback will be called for every excerpt intersecting the given range. It will
3760    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3761    /// The callback should return an iterator of metadata items from that buffer, each paired
3762    /// with a buffer range.
3763    ///
3764    /// The returned iterator yields each of these metadata items, paired with its range in
3765    /// multi-buffer coordinates.
3766    fn lift_buffer_metadata<'a, MBD, M, I>(
3767        &'a self,
3768        query_range: Range<MBD>,
3769        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3770    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3771    where
3772        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3773        MBD: MultiBufferDimension
3774            + Ord
3775            + Sub<Output = MBD::TextDimension>
3776            + ops::Add<MBD::TextDimension, Output = MBD>
3777            + ops::AddAssign<MBD::TextDimension>,
3778        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3779            + ops::Add<Output = MBD::TextDimension>
3780            + AddAssign<MBD::TextDimension>
3781            + Ord,
3782    {
3783        let mut current_excerpt_metadata: Option<(ExcerptRange<text::Anchor>, I)> = None;
3784        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3785
3786        // Find the excerpt and buffer offset where the given range ends.
3787        cursor.seek(&query_range.end);
3788        let mut range_end = None;
3789        while let Some(region) = cursor.region() {
3790            if region.is_main_buffer {
3791                let mut buffer_end = region.buffer_range.start;
3792                let overshoot = if query_range.end > region.range.start {
3793                    query_range.end - region.range.start
3794                } else {
3795                    <MBD::TextDimension>::default()
3796                };
3797                buffer_end = buffer_end + overshoot;
3798                range_end = Some((region.excerpt.range.clone(), buffer_end));
3799                break;
3800            }
3801            cursor.next();
3802        }
3803
3804        cursor.seek(&query_range.start);
3805
3806        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3807            && region.range.start > MBD::default()
3808        {
3809            cursor.prev()
3810        } else if let Some(region) = cursor.region()
3811            && region.is_main_buffer
3812            && region.diff_hunk_status.is_some()
3813        {
3814            cursor.prev();
3815            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3816                cursor.next();
3817            }
3818        }
3819
3820        iter::from_fn(move || {
3821            loop {
3822                let excerpt = cursor.excerpt()?;
3823                let buffer_snapshot = excerpt.buffer_snapshot(self);
3824
3825                // If we have already retrieved metadata for this excerpt, continue to use it.
3826                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3827                    .as_mut()
3828                    .filter(|(excerpt_info, _)| excerpt_info == &excerpt.range)
3829                {
3830                    Some(metadata)
3831                }
3832                // Otherwise, compute the intersection of the input range with the excerpt's range,
3833                // and retrieve the metadata for the resulting range.
3834                else {
3835                    let region = cursor.region()?;
3836                    let mut buffer_start;
3837                    if region.is_main_buffer {
3838                        buffer_start = region.buffer_range.start;
3839                        if query_range.start > region.range.start {
3840                            let overshoot = query_range.start - region.range.start;
3841                            buffer_start = buffer_start + overshoot;
3842                        }
3843                        buffer_start = buffer_start.min(region.buffer_range.end);
3844                    } else {
3845                        buffer_start = cursor.main_buffer_position()?;
3846                    };
3847                    let mut buffer_end = excerpt
3848                        .range
3849                        .context
3850                        .end
3851                        .summary::<MBD::TextDimension>(&buffer_snapshot);
3852                    if let Some((end_excerpt, end_buffer_offset)) = &range_end
3853                        && &excerpt.range == end_excerpt
3854                    {
3855                        buffer_end = buffer_end.min(*end_buffer_offset);
3856                    }
3857
3858                    get_buffer_metadata(&buffer_snapshot, buffer_start..buffer_end).map(
3859                        |iterator| {
3860                            &mut current_excerpt_metadata
3861                                .insert((excerpt.range.clone(), iterator))
3862                                .1
3863                        },
3864                    )
3865                };
3866
3867                // Visit each metadata item.
3868                if let Some((metadata_buffer_range, metadata)) =
3869                    metadata_iter.and_then(Iterator::next)
3870                {
3871                    // Find the multibuffer regions that contain the start and end of
3872                    // the metadata item's range.
3873                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3874                        while let Some(region) = cursor.region() {
3875                            if (region.is_main_buffer
3876                                && (region.buffer_range.end >= metadata_buffer_range.start
3877                                    || cursor.is_at_end_of_excerpt()))
3878                                || (!region.is_main_buffer
3879                                    && region.buffer_range.start == metadata_buffer_range.start)
3880                            {
3881                                break;
3882                            }
3883                            cursor.next();
3884                        }
3885                    }
3886                    let start_region = cursor.region()?.clone();
3887                    while let Some(region) = cursor.region() {
3888                        if region.is_main_buffer
3889                            && (region.buffer_range.end > metadata_buffer_range.end
3890                                || cursor.is_at_end_of_excerpt())
3891                        {
3892                            break;
3893                        }
3894                        cursor.next();
3895                    }
3896                    let end_region = cursor.region();
3897
3898                    // Convert the metadata item's range into multibuffer coordinates.
3899                    let mut start_position = start_region.range.start;
3900                    let region_buffer_start = start_region.buffer_range.start;
3901                    if start_region.is_main_buffer
3902                        && metadata_buffer_range.start > region_buffer_start
3903                    {
3904                        start_position =
3905                            start_position + (metadata_buffer_range.start - region_buffer_start);
3906                        start_position = start_position.min(start_region.range.end);
3907                    }
3908
3909                    let mut end_position = self.max_position();
3910                    if let Some(end_region) = &end_region {
3911                        end_position = end_region.range.start;
3912                        debug_assert!(end_region.is_main_buffer);
3913                        let region_buffer_start = end_region.buffer_range.start;
3914                        if metadata_buffer_range.end > region_buffer_start {
3915                            end_position =
3916                                end_position + (metadata_buffer_range.end - region_buffer_start);
3917                        }
3918                        end_position = end_position.min(end_region.range.end);
3919                    }
3920
3921                    if start_position <= query_range.end && end_position >= query_range.start {
3922                        return Some((start_position..end_position, metadata, excerpt));
3923                    }
3924                }
3925                // When there are no more metadata items for this excerpt, move to the next excerpt.
3926                else {
3927                    current_excerpt_metadata.take();
3928                    if let Some((end_excerpt, _)) = &range_end
3929                        && &excerpt.range == end_excerpt
3930                    {
3931                        return None;
3932                    }
3933                    cursor.next_excerpt_forwards();
3934                }
3935            }
3936        })
3937    }
3938
3939    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3940        let offset = position.to_offset(self);
3941
3942        let mut cursor = self
3943            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
3944            );
3945        cursor.seek(&DimensionPair {
3946            key: offset,
3947            value: None,
3948        });
3949        cursor.seek_to_start_of_current_excerpt();
3950        let excerpt = cursor.excerpt()?;
3951
3952        let buffer = excerpt.buffer_snapshot(self);
3953        let excerpt_start = excerpt.range.context.start.to_offset(buffer);
3954        let excerpt_end = excerpt.range.context.end.to_offset(buffer);
3955        let current_position = match self.anchor_before(offset) {
3956            Anchor::Min => 0,
3957            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.text_anchor().to_offset(buffer),
3958            Anchor::Max => unreachable!(),
3959        };
3960
3961        if let Some(diff) = self.diff_state(excerpt.buffer_id) {
3962            if let Some(main_buffer) = &diff.main_buffer {
3963                for hunk in diff
3964                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
3965                {
3966                    if hunk.diff_base_byte_range.end >= current_position {
3967                        continue;
3968                    }
3969                    let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
3970                    let start =
3971                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
3972                    return Some(MultiBufferRow(start.row));
3973                }
3974            } else {
3975                let excerpt_end = buffer.anchor_before(excerpt_end.min(current_position));
3976                for hunk in diff
3977                    .hunks_intersecting_range_rev(excerpt.range.context.start..excerpt_end, buffer)
3978                {
3979                    let hunk_end = hunk.buffer_range.end.to_offset(buffer);
3980                    if hunk_end >= current_position {
3981                        continue;
3982                    }
3983                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3984                        .to_point(self);
3985                    return Some(MultiBufferRow(start.row));
3986                }
3987            }
3988        }
3989
3990        loop {
3991            cursor.prev_excerpt();
3992            let excerpt = cursor.excerpt()?;
3993            let buffer = excerpt.buffer_snapshot(self);
3994
3995            let Some(diff) = self.diff_state(excerpt.buffer_id) else {
3996                continue;
3997            };
3998            if let Some(main_buffer) = &diff.main_buffer {
3999                let Some(hunk) = diff
4000                    .hunks_intersecting_base_text_range_rev(
4001                        excerpt.range.context.to_offset(buffer),
4002                        main_buffer,
4003                    )
4004                    .next()
4005                else {
4006                    continue;
4007                };
4008                let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4009                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4010                return Some(MultiBufferRow(start.row));
4011            } else {
4012                let Some(hunk) = diff
4013                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), buffer)
4014                    .next()
4015                else {
4016                    continue;
4017                };
4018                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4019                    .to_point(self);
4020                return Some(MultiBufferRow(start.row));
4021            }
4022        }
4023    }
4024
4025    pub fn has_diff_hunks(&self) -> bool {
4026        self.diffs.iter().any(|diff| !diff.is_empty())
4027    }
4028
4029    pub fn is_inside_word<T: ToOffset>(
4030        &self,
4031        position: T,
4032        scope_context: Option<CharScopeContext>,
4033    ) -> bool {
4034        let position = position.to_offset(self);
4035        let classifier = self
4036            .char_classifier_at(position)
4037            .scope_context(scope_context);
4038        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4039        let prev_char_kind = self
4040            .reversed_chars_at(position)
4041            .next()
4042            .map(|c| classifier.kind(c));
4043        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4044    }
4045
4046    pub fn surrounding_word<T: ToOffset>(
4047        &self,
4048        start: T,
4049        scope_context: Option<CharScopeContext>,
4050    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4051        let mut start = start.to_offset(self);
4052        let mut end = start;
4053        let mut next_chars = self.chars_at(start).peekable();
4054        let mut prev_chars = self.reversed_chars_at(start).peekable();
4055
4056        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4057
4058        let word_kind = cmp::max(
4059            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4060            next_chars.peek().copied().map(|c| classifier.kind(c)),
4061        );
4062
4063        for ch in prev_chars {
4064            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4065                start -= ch.len_utf8();
4066            } else {
4067                break;
4068            }
4069        }
4070
4071        for ch in next_chars {
4072            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4073                end += ch.len_utf8();
4074            } else {
4075                break;
4076            }
4077        }
4078
4079        (start..end, word_kind)
4080    }
4081
4082    pub fn char_kind_before<T: ToOffset>(
4083        &self,
4084        start: T,
4085        scope_context: Option<CharScopeContext>,
4086    ) -> Option<CharKind> {
4087        let start = start.to_offset(self);
4088        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4089        self.reversed_chars_at(start)
4090            .next()
4091            .map(|ch| classifier.kind(ch))
4092    }
4093
4094    pub fn all_buffer_ids(&self) -> impl Iterator<Item = BufferId> + '_ {
4095        self.buffers.iter().map(|(id, _)| *id)
4096    }
4097
4098    pub fn is_singleton(&self) -> bool {
4099        self.singleton
4100    }
4101
4102    pub fn as_singleton(&self) -> Option<&BufferSnapshot> {
4103        if self.is_singleton() {
4104            Some(self.excerpts.first()?.buffer_snapshot(&self))
4105        } else {
4106            None
4107        }
4108    }
4109
4110    pub fn len(&self) -> MultiBufferOffset {
4111        self.diff_transforms.summary().output.len
4112    }
4113
4114    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4115        MBD::from_summary(&self.text_summary())
4116    }
4117
4118    pub fn is_empty(&self) -> bool {
4119        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4120    }
4121
4122    pub fn widest_line_number(&self) -> u32 {
4123        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4124        self.excerpts.summary().widest_line_number + 1
4125    }
4126
4127    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4128        let range = range.start.to_offset(self)..range.end.to_offset(self);
4129        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4130        excerpts.seek(&range.start);
4131
4132        let mut chunk;
4133        let mut has_trailing_newline;
4134        let excerpt_bytes;
4135        if let Some(region) = excerpts.region() {
4136            let mut bytes = region.buffer.bytes_in_range(
4137                region.buffer_range.start + (range.start - region.range.start)
4138                    ..(region.buffer_range.start + (range.end - region.range.start))
4139                        .min(region.buffer_range.end),
4140            );
4141            chunk = bytes.next().unwrap_or(&[][..]);
4142            excerpt_bytes = Some(bytes);
4143            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4144            if chunk.is_empty() && has_trailing_newline {
4145                chunk = b"\n";
4146                has_trailing_newline = false;
4147            }
4148        } else {
4149            chunk = &[][..];
4150            excerpt_bytes = None;
4151            has_trailing_newline = false;
4152        };
4153
4154        MultiBufferBytes {
4155            range,
4156            cursor: excerpts,
4157            excerpt_bytes,
4158            has_trailing_newline,
4159            chunk,
4160        }
4161    }
4162
4163    pub fn reversed_bytes_in_range<T: ToOffset>(
4164        &self,
4165        range: Range<T>,
4166    ) -> ReversedMultiBufferBytes<'_> {
4167        let range = range.start.to_offset(self)..range.end.to_offset(self);
4168        let mut chunks = self.reversed_chunks_in_range(range.clone());
4169        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4170        ReversedMultiBufferBytes {
4171            range,
4172            chunks,
4173            chunk,
4174        }
4175    }
4176
4177    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4178        let mut cursor = self.cursor::<Point, Point>();
4179        cursor.seek(&Point::new(start_row.0, 0));
4180        let mut result = MultiBufferRows {
4181            point: Point::new(0, 0),
4182            is_empty: self.excerpts.is_empty(),
4183            is_singleton: self.is_singleton(),
4184            cursor,
4185        };
4186        result.seek(start_row);
4187        result
4188    }
4189
4190    pub fn chunks<T: ToOffset>(
4191        &self,
4192        range: Range<T>,
4193        language_aware: LanguageAwareStyling,
4194    ) -> MultiBufferChunks<'_> {
4195        let mut chunks = MultiBufferChunks {
4196            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4197                ..ExcerptDimension(MultiBufferOffset::ZERO),
4198            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4199            excerpts: self.excerpts.cursor(()),
4200            diff_transforms: self.diff_transforms.cursor(()),
4201            diff_base_chunks: None,
4202            excerpt_chunks: None,
4203            buffer_chunk: None,
4204            language_aware,
4205            snapshot: self,
4206        };
4207        let range = range.start.to_offset(self)..range.end.to_offset(self);
4208        chunks.seek(range);
4209        chunks
4210    }
4211
4212    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4213        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4214    }
4215
4216    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4217        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4218    }
4219
4220    pub fn clip_offset_utf16(
4221        &self,
4222        offset: MultiBufferOffsetUtf16,
4223        bias: Bias,
4224    ) -> MultiBufferOffsetUtf16 {
4225        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4226    }
4227
4228    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4229        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4230            buffer.clip_point_utf16(Unclipped(point), bias)
4231        })
4232    }
4233
4234    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4235        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4236    }
4237
4238    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4239        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4240    }
4241
4242    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4243        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4244    }
4245
4246    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4247        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4248    }
4249
4250    #[instrument(skip_all)]
4251    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4252        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4253    }
4254
4255    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4256        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4257    }
4258
4259    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4260        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4261    }
4262
4263    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4264        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4265    }
4266
4267    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4268        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4269    }
4270
4271    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4272        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4273    }
4274
4275    fn clip_dimension<MBD, BD>(
4276        &self,
4277        position: MBD,
4278        bias: Bias,
4279        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4280    ) -> MBD
4281    where
4282        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4283        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4284    {
4285        let mut cursor = self.cursor::<MBD, BD>();
4286        cursor.seek(&position);
4287        if let Some(region) = cursor.region() {
4288            if position >= region.range.end {
4289                return region.range.end;
4290            }
4291            let overshoot = position - region.range.start;
4292            let mut buffer_position = region.buffer_range.start;
4293            buffer_position += overshoot;
4294            let clipped_buffer_position =
4295                clip_buffer_position(region.buffer, buffer_position, bias);
4296            let mut position = region.range.start;
4297            position += clipped_buffer_position - region.buffer_range.start;
4298            position
4299        } else {
4300            self.max_position()
4301        }
4302    }
4303
4304    #[instrument(skip_all)]
4305    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4306        &self,
4307        key: MBR1,
4308        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4309    ) -> MBR2
4310    where
4311        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4312        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4313        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4314        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4315    {
4316        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4317        cursor.seek(&DimensionPair { key, value: None });
4318        if let Some(region) = cursor.region() {
4319            if key >= region.range.end.key {
4320                return region.range.end.value.unwrap();
4321            }
4322            let start_key = region.range.start.key;
4323            let start_value = region.range.start.value.unwrap();
4324            let buffer_start_key = region.buffer_range.start.key;
4325            let buffer_start_value = region.buffer_range.start.value.unwrap();
4326            let mut buffer_key = buffer_start_key;
4327            buffer_key += key - start_key;
4328            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4329            let mut result = start_value;
4330            result += buffer_value - buffer_start_value;
4331            result
4332        } else {
4333            self.max_position()
4334        }
4335    }
4336
4337    pub fn point_to_buffer_offset<T: ToOffset>(
4338        &self,
4339        point: T,
4340    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4341        let offset = point.to_offset(self);
4342        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4343        cursor.seek(&offset);
4344        let region = cursor.region()?;
4345        let overshoot = offset - region.range.start;
4346        let buffer_offset = region.buffer_range.start + overshoot;
4347        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4348            && region.has_trailing_newline
4349            && !region.is_main_buffer
4350        {
4351            let main_buffer_position = cursor.main_buffer_position()?;
4352            let buffer_snapshot = cursor.excerpt()?.buffer_snapshot(self);
4353            return Some((buffer_snapshot, main_buffer_position));
4354        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4355            return None;
4356        }
4357        Some((region.buffer, buffer_offset))
4358    }
4359
4360    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4361        let mut cursor = self.cursor::<Point, Point>();
4362        cursor.seek(&point);
4363        let region = cursor.region()?;
4364        let overshoot = point - region.range.start;
4365        let buffer_point = region.buffer_range.start + overshoot;
4366        let excerpt = cursor.excerpt()?;
4367        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4368            && region.has_trailing_newline
4369            && !region.is_main_buffer
4370        {
4371            return Some((
4372                &excerpt.buffer_snapshot(self),
4373                cursor.main_buffer_position()?,
4374            ));
4375        } else if buffer_point > region.buffer.max_point() {
4376            return None;
4377        }
4378        Some((region.buffer, buffer_point))
4379    }
4380
4381    pub fn suggested_indents(
4382        &self,
4383        rows: impl IntoIterator<Item = u32>,
4384        cx: &App,
4385    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4386        let mut result = BTreeMap::new();
4387        self.suggested_indents_callback(
4388            rows,
4389            &mut |row, indent| {
4390                result.insert(row, indent);
4391                ControlFlow::Continue(())
4392            },
4393            cx,
4394        );
4395        result
4396    }
4397
4398    // move this to be a generator once those are a thing
4399    pub fn suggested_indents_callback(
4400        &self,
4401        rows: impl IntoIterator<Item = u32>,
4402        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4403        cx: &App,
4404    ) {
4405        let mut rows_for_excerpt = Vec::new();
4406        let mut cursor = self.cursor::<Point, Point>();
4407        let mut rows = rows.into_iter().peekable();
4408        let mut prev_row = u32::MAX;
4409        let mut prev_language_indent_size = IndentSize::default();
4410
4411        while let Some(row) = rows.next() {
4412            cursor.seek(&Point::new(row, 0));
4413            let Some(region) = cursor.region() else {
4414                continue;
4415            };
4416
4417            // Retrieve the language and indent size once for each disjoint region being indented.
4418            let single_indent_size = if row.saturating_sub(1) == prev_row {
4419                prev_language_indent_size
4420            } else {
4421                region
4422                    .buffer
4423                    .language_indent_size_at(Point::new(row, 0), cx)
4424            };
4425            prev_language_indent_size = single_indent_size;
4426            prev_row = row;
4427
4428            let start_buffer_row = region.buffer_range.start.row;
4429            let start_multibuffer_row = region.range.start.row;
4430            let end_multibuffer_row = region.range.end.row;
4431
4432            rows_for_excerpt.push(row);
4433            while let Some(next_row) = rows.peek().copied() {
4434                if end_multibuffer_row > next_row {
4435                    rows_for_excerpt.push(next_row);
4436                    rows.next();
4437                } else {
4438                    break;
4439                }
4440            }
4441
4442            let buffer_rows = rows_for_excerpt
4443                .drain(..)
4444                .map(|row| start_buffer_row + row - start_multibuffer_row);
4445            let buffer_indents = region
4446                .buffer
4447                .suggested_indents(buffer_rows, single_indent_size);
4448            for (row, indent) in buffer_indents {
4449                if cb(
4450                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4451                    indent,
4452                )
4453                .is_break()
4454                {
4455                    return;
4456                }
4457            }
4458        }
4459    }
4460
4461    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4462        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4463            let mut size = buffer.indent_size_for_line(range.start.row);
4464            size.len = size
4465                .len
4466                .min(range.end.column)
4467                .saturating_sub(range.start.column);
4468            size
4469        } else {
4470            IndentSize::spaces(0)
4471        }
4472    }
4473
4474    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4475        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4476            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4477        } else {
4478            LineIndent::spaces(0)
4479        }
4480    }
4481
4482    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4483        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4484
4485        if self.language_settings(cx).extend_comment_on_newline
4486            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4487        {
4488            let delimiters = language_scope.line_comment_prefixes();
4489            for delimiter in delimiters {
4490                if *self
4491                    .chars_at(Point::new(row.0, indent.len() as u32))
4492                    .take(delimiter.chars().count())
4493                    .collect::<String>()
4494                    .as_str()
4495                    == **delimiter
4496                {
4497                    indent.push_str(delimiter);
4498                    break;
4499                }
4500            }
4501        }
4502
4503        indent
4504    }
4505
4506    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4507    where
4508        T: ToOffset,
4509    {
4510        for char in self.reversed_chars_at(position) {
4511            if !char.is_whitespace() {
4512                return false;
4513            }
4514            if char == '\n' {
4515                return true;
4516            }
4517        }
4518        true
4519    }
4520
4521    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4522        while row.0 > 0 {
4523            row.0 -= 1;
4524            if !self.is_line_blank(row) {
4525                return Some(row);
4526            }
4527        }
4528        None
4529    }
4530
4531    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4532        if let Some((_, range)) = self.buffer_line_for_row(row) {
4533            range.end.column - range.start.column
4534        } else {
4535            0
4536        }
4537    }
4538
4539    pub fn line_len_utf16(&self, row: MultiBufferRow) -> u32 {
4540        self.clip_point_utf16(Unclipped(PointUtf16::new(row.0, u32::MAX)), Bias::Left)
4541            .column
4542    }
4543
4544    pub fn buffer_line_for_row(
4545        &self,
4546        row: MultiBufferRow,
4547    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4548        let mut cursor = self.cursor::<Point, Point>();
4549        let point = Point::new(row.0, 0);
4550        cursor.seek(&point);
4551        let region = cursor.region()?;
4552        let overshoot = point.min(region.range.end) - region.range.start;
4553        let buffer_point = region.buffer_range.start + overshoot;
4554        if buffer_point.row > region.buffer_range.end.row {
4555            return None;
4556        }
4557        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4558        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4559            .min(region.buffer_range.end);
4560        Some((region.buffer, line_start..line_end))
4561    }
4562
4563    pub fn max_point(&self) -> Point {
4564        self.text_summary().lines
4565    }
4566
4567    pub fn max_row(&self) -> MultiBufferRow {
4568        MultiBufferRow(self.text_summary().lines.row)
4569    }
4570
4571    pub fn text_summary(&self) -> MBTextSummary {
4572        self.diff_transforms.summary().output
4573    }
4574
4575    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4576    where
4577        MBD: MultiBufferDimension + AddAssign,
4578        O: ToOffset,
4579    {
4580        let range = range.start.to_offset(self)..range.end.to_offset(self);
4581        let mut cursor = self
4582            .diff_transforms
4583            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4584        cursor.seek(&range.start, Bias::Right);
4585
4586        let Some(first_transform) = cursor.item() else {
4587            return MBD::from_summary(&MBTextSummary::default());
4588        };
4589
4590        let diff_transform_start = cursor.start().0;
4591        let diff_transform_end = cursor.end().0;
4592        let diff_start = range.start;
4593        let start_overshoot = diff_start - diff_transform_start;
4594        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4595
4596        let mut result = match first_transform {
4597            DiffTransform::BufferContent { .. } => {
4598                let excerpt_start = cursor.start().1 + start_overshoot;
4599                let excerpt_end = cursor.start().1 + end_overshoot;
4600                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4601            }
4602            DiffTransform::DeletedHunk {
4603                buffer_id,
4604                base_text_byte_range,
4605                has_trailing_newline,
4606                ..
4607            } => {
4608                let buffer_start = base_text_byte_range.start + start_overshoot;
4609                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4610                let Some(base_text) = self.diff_state(*buffer_id).map(|diff| diff.base_text())
4611                else {
4612                    panic!("{:?} is in non-existent deleted hunk", range.start)
4613                };
4614
4615                let include_trailing_newline =
4616                    *has_trailing_newline && range.end >= diff_transform_end;
4617                if include_trailing_newline {
4618                    buffer_end -= 1;
4619                }
4620
4621                let mut summary = base_text
4622                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4623
4624                if include_trailing_newline {
4625                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4626                        &TextSummary::newline(),
4627                    ))
4628                }
4629
4630                let mut result = MBD::default();
4631                result.add_text_dim(&summary);
4632                result
4633            }
4634        };
4635        if range.end < diff_transform_end {
4636            return result;
4637        }
4638
4639        cursor.next();
4640        result.add_mb_text_summary(
4641            &cursor
4642                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4643                .0,
4644        );
4645
4646        let Some(last_transform) = cursor.item() else {
4647            return result;
4648        };
4649
4650        let overshoot = range.end - cursor.start().0;
4651        let suffix = match last_transform {
4652            DiffTransform::BufferContent { .. } => {
4653                let end = cursor.start().1 + overshoot;
4654                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4655            }
4656            DiffTransform::DeletedHunk {
4657                base_text_byte_range,
4658                buffer_id,
4659                has_trailing_newline,
4660                ..
4661            } => {
4662                let buffer_end = base_text_byte_range.start + overshoot;
4663                let Some(base_text) = self.diff_state(*buffer_id).map(|diff| diff.base_text())
4664                else {
4665                    panic!("{:?} is in non-existent deleted hunk", range.end)
4666                };
4667
4668                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4669                    base_text_byte_range.start..buffer_end,
4670                );
4671                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4672                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4673                        &TextSummary::from("\n"),
4674                    ))
4675                }
4676
4677                let mut result = MBD::default();
4678                result.add_text_dim(&suffix);
4679                result
4680            }
4681        };
4682
4683        result += suffix;
4684        result
4685    }
4686
4687    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4688    where
4689        MBD: MultiBufferDimension + AddAssign,
4690    {
4691        let mut summary = MBD::default();
4692        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4693        cursor.seek(&range.start, Bias::Right);
4694        if let Some(excerpt) = cursor.item() {
4695            let buffer_snapshot = excerpt.buffer_snapshot(self);
4696            let mut end_before_newline = cursor.end();
4697            if excerpt.has_trailing_newline {
4698                end_before_newline -= 1;
4699            }
4700
4701            let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4702            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4703            let end_in_excerpt =
4704                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4705            summary.add_text_dim(
4706                &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4707                    start_in_excerpt..end_in_excerpt,
4708                ),
4709            );
4710
4711            if range.end > end_before_newline {
4712                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4713            }
4714
4715            cursor.next();
4716        }
4717
4718        if range.end > *cursor.start() {
4719            summary += cursor
4720                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4721                .0;
4722            if let Some(excerpt) = cursor.item() {
4723                let buffer_snapshot = excerpt.buffer_snapshot(self);
4724                range.end = cmp::max(*cursor.start(), range.end);
4725
4726                let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4727                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4728                summary.add_text_dim(
4729                    &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4730                        excerpt_start..end_in_excerpt,
4731                    ),
4732                );
4733            }
4734        }
4735
4736        summary
4737    }
4738
4739    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4740    where
4741        MBD: MultiBufferDimension
4742            + Ord
4743            + Sub<Output = MBD::TextDimension>
4744            + Sub<MBD::TextDimension, Output = MBD>
4745            + AddAssign<MBD::TextDimension>
4746            + Add<MBD::TextDimension, Output = MBD>,
4747        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4748    {
4749        let target = anchor.seek_target(self);
4750        let anchor = match anchor {
4751            Anchor::Min => {
4752                return MBD::default();
4753            }
4754            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4755            Anchor::Max => {
4756                return MBD::from_summary(&self.text_summary());
4757            }
4758        };
4759
4760        let (start, _, item) = self
4761            .excerpts
4762            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4763        let start = MBD::from_summary(&start.text);
4764
4765        let excerpt_start_position = ExcerptDimension(start);
4766        if self.diff_transforms.is_empty() {
4767            if let Some(excerpt) = item {
4768                if !excerpt.contains(anchor, self) {
4769                    return excerpt_start_position.0;
4770                }
4771                let buffer_snapshot = excerpt.buffer_snapshot(self);
4772                let excerpt_buffer_start = excerpt
4773                    .range
4774                    .context
4775                    .start
4776                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4777                let excerpt_buffer_end = excerpt
4778                    .range
4779                    .context
4780                    .end
4781                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4782                let buffer_summary = anchor
4783                    .text_anchor()
4784                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4785                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4786                let mut position = excerpt_start_position;
4787                if summary > excerpt_buffer_start {
4788                    position += summary - excerpt_buffer_start;
4789                }
4790
4791                position.0
4792            } else {
4793                excerpt_start_position.0
4794            }
4795        } else {
4796            let mut diff_transforms_cursor = self
4797                .diff_transforms
4798                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4799
4800            if let Some(excerpt) = item {
4801                if !excerpt.contains(anchor, self) {
4802                    diff_transforms_cursor.seek(&excerpt_start_position, Bias::Left);
4803                    return self.summary_for_excerpt_position_without_hunks(
4804                        Bias::Left,
4805                        excerpt_start_position,
4806                        &mut diff_transforms_cursor,
4807                    );
4808                }
4809                let buffer_snapshot = excerpt.buffer_snapshot(self);
4810                let excerpt_buffer_start = excerpt
4811                    .range
4812                    .context
4813                    .start
4814                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4815                let excerpt_buffer_end = excerpt
4816                    .range
4817                    .context
4818                    .end
4819                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4820                let buffer_summary = anchor
4821                    .text_anchor()
4822                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4823                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4824                let mut position = excerpt_start_position;
4825                if summary > excerpt_buffer_start {
4826                    position += summary - excerpt_buffer_start;
4827                }
4828
4829                diff_transforms_cursor.seek(&position, Bias::Left);
4830                self.summary_for_anchor_with_excerpt_position(
4831                    *anchor,
4832                    position,
4833                    &mut diff_transforms_cursor,
4834                    &buffer_snapshot,
4835                )
4836            } else {
4837                diff_transforms_cursor.seek(&excerpt_start_position, Bias::Left);
4838                self.summary_for_excerpt_position_without_hunks(
4839                    Bias::Right,
4840                    excerpt_start_position,
4841                    &mut diff_transforms_cursor,
4842                )
4843            }
4844        }
4845    }
4846
4847    /// Maps an anchor's excerpt-space position to its output-space position by
4848    /// walking the diff transforms. The cursor is shared across consecutive
4849    /// calls, so it may already be partway through the transform list.
4850    fn summary_for_anchor_with_excerpt_position<MBD>(
4851        &self,
4852        anchor: ExcerptAnchor,
4853        excerpt_position: ExcerptDimension<MBD>,
4854        diff_transforms: &mut Cursor<
4855            DiffTransform,
4856            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4857        >,
4858        excerpt_buffer: &text::BufferSnapshot,
4859    ) -> MBD
4860    where
4861        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4862    {
4863        loop {
4864            let transform_end_position = diff_transforms.end().0;
4865            let item = diff_transforms.item();
4866            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4867
4868            // A right-biased anchor at a transform boundary belongs to the
4869            // *next* transform, so advance past the current one.
4870            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
4871                diff_transforms.next();
4872                continue;
4873            }
4874
4875            let mut position = diff_transforms.start().1;
4876            match item {
4877                Some(DiffTransform::DeletedHunk {
4878                    buffer_id,
4879                    base_text_byte_range,
4880                    hunk_info,
4881                    ..
4882                }) => {
4883                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4884                        && let Some(base_text) =
4885                            self.diff_state(*buffer_id).map(|diff| diff.base_text())
4886                        && diff_base_anchor.is_valid(&base_text)
4887                    {
4888                        // The anchor carries a diff-base position — resolve it
4889                        // to a location inside the deleted hunk.
4890                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4891                        if base_text_offset >= base_text_byte_range.start
4892                            && base_text_offset <= base_text_byte_range.end
4893                        {
4894                            let position_in_hunk = base_text
4895                                .text_summary_for_range::<MBD::TextDimension, _>(
4896                                    base_text_byte_range.start..base_text_offset,
4897                                );
4898                            position.0.add_text_dim(&position_in_hunk);
4899                        } else if at_transform_end {
4900                            // diff_base offset falls outside this hunk's range;
4901                            // advance to see if the next transform is a better fit.
4902                            diff_transforms.next();
4903                            continue;
4904                        }
4905                    } else if at_transform_end
4906                        && anchor
4907                            .text_anchor()
4908                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4909                            .is_gt()
4910                    {
4911                        // The anchor has no (valid) diff-base position, so it
4912                        // belongs in the buffer content, not in the deleted
4913                        // hunk. However, after an edit deletes the text between
4914                        // the hunk boundary and this anchor, both resolve to
4915                        // the same excerpt_position—landing us here on the
4916                        // DeletedHunk left behind by the shared cursor. Use the
4917                        // CRDT ordering to detect that the anchor is strictly
4918                        // *past* the hunk boundary and skip to the following
4919                        // BufferContent.
4920                        diff_transforms.next();
4921                        continue;
4922                    }
4923                }
4924                _ => {
4925                    // On a BufferContent (or no transform). If the anchor
4926                    // carries a diff_base_anchor it needs a DeletedHunk, so
4927                    // advance to find one.
4928                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4929                        diff_transforms.next();
4930                        continue;
4931                    }
4932                    let overshoot = excerpt_position - diff_transforms.start().0;
4933                    position += overshoot;
4934                }
4935            }
4936
4937            return position.0;
4938        }
4939    }
4940
4941    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4942    fn summary_for_excerpt_position_without_hunks<MBD>(
4943        &self,
4944        bias: Bias,
4945        excerpt_position: ExcerptDimension<MBD>,
4946        diff_transforms: &mut Cursor<
4947            DiffTransform,
4948            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4949        >,
4950    ) -> MBD
4951    where
4952        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4953    {
4954        loop {
4955            let transform_end_position = diff_transforms.end().0;
4956            let item = diff_transforms.item();
4957            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4958
4959            // A right-biased anchor at a transform boundary belongs to the
4960            // *next* transform, so advance past the current one.
4961            if bias == Bias::Right && at_transform_end {
4962                diff_transforms.next();
4963                continue;
4964            }
4965
4966            let mut position = diff_transforms.start().1;
4967            if let Some(DiffTransform::BufferContent { .. }) | None = item {
4968                let overshoot = excerpt_position - diff_transforms.start().0;
4969                position += overshoot;
4970            }
4971
4972            return position.0;
4973        }
4974    }
4975
4976    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4977        let anchor = match anchor {
4978            Anchor::Min => return ExcerptOffset::default(),
4979            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4980            Anchor::Max => return self.excerpts.summary().len(),
4981        };
4982        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4983        let target = anchor.seek_target(self);
4984
4985        cursor.seek(&target, Bias::Left);
4986
4987        let mut position = cursor.start().len();
4988        if let Some(excerpt) = cursor.item()
4989            && excerpt.contains(anchor, self)
4990        {
4991            let buffer_snapshot = excerpt.buffer_snapshot(self);
4992            let excerpt_buffer_start =
4993                buffer_snapshot.offset_for_anchor(&excerpt.range.context.start);
4994            let excerpt_buffer_end = buffer_snapshot.offset_for_anchor(&excerpt.range.context.end);
4995            let buffer_position = cmp::min(
4996                excerpt_buffer_end,
4997                buffer_snapshot.offset_for_anchor(&anchor.text_anchor()),
4998            );
4999            if buffer_position > excerpt_buffer_start {
5000                position += buffer_position - excerpt_buffer_start;
5001            }
5002        }
5003        position
5004    }
5005
5006    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5007    where
5008        MBD: MultiBufferDimension
5009            + Ord
5010            + Sub<Output = MBD::TextDimension>
5011            + AddAssign<MBD::TextDimension>,
5012        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5013        I: 'a + IntoIterator<Item = &'a Anchor>,
5014    {
5015        let mut anchors = anchors.into_iter().peekable();
5016        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5017        let mut diff_transforms_cursor = self
5018            .diff_transforms
5019            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5020        diff_transforms_cursor.next();
5021
5022        let mut summaries = Vec::new();
5023        while let Some(anchor) = anchors.peek() {
5024            let target = anchor.seek_target(self);
5025            let excerpt_anchor = match anchor {
5026                Anchor::Min => {
5027                    summaries.push(MBD::default());
5028                    anchors.next();
5029                    continue;
5030                }
5031                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5032                Anchor::Max => {
5033                    summaries.push(MBD::from_summary(&self.text_summary()));
5034                    anchors.next();
5035                    continue;
5036                }
5037            };
5038
5039            cursor.seek_forward(&target, Bias::Left);
5040
5041            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5042            if let Some(excerpt) = cursor.item() {
5043                let buffer_snapshot = excerpt.buffer_snapshot(self);
5044                if !excerpt.contains(&excerpt_anchor, self) {
5045                    diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5046                    let position = self.summary_for_excerpt_position_without_hunks(
5047                        Bias::Left,
5048                        excerpt_start_position,
5049                        &mut diff_transforms_cursor,
5050                    );
5051                    summaries.push(position);
5052                    anchors.next();
5053                    continue;
5054                }
5055                let excerpt_buffer_start = excerpt
5056                    .range
5057                    .context
5058                    .start
5059                    .summary::<MBD::TextDimension>(buffer_snapshot);
5060                let excerpt_buffer_end = excerpt
5061                    .range
5062                    .context
5063                    .end
5064                    .summary::<MBD::TextDimension>(buffer_snapshot);
5065                for (buffer_summary, excerpt_anchor) in buffer_snapshot
5066                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5067                        std::iter::from_fn(|| {
5068                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5069                            if !excerpt.contains(&excerpt_anchor, self) {
5070                                return None;
5071                            }
5072                            anchors.next();
5073                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5074                        }),
5075                    )
5076                {
5077                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5078                    let mut position = excerpt_start_position;
5079                    if summary > excerpt_buffer_start {
5080                        position += summary - excerpt_buffer_start;
5081                    }
5082
5083                    if diff_transforms_cursor.start().0 < position {
5084                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5085                    }
5086
5087                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5088                        excerpt_anchor,
5089                        position,
5090                        &mut diff_transforms_cursor,
5091                        &buffer_snapshot,
5092                    ));
5093                }
5094            } else {
5095                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5096                let position = self.summary_for_excerpt_position_without_hunks(
5097                    Bias::Right,
5098                    excerpt_start_position,
5099                    &mut diff_transforms_cursor,
5100                );
5101                summaries.push(position);
5102                anchors.next();
5103            }
5104        }
5105
5106        summaries
5107    }
5108
5109    pub fn dimensions_from_points<'a, MBD>(
5110        &'a self,
5111        points: impl 'a + IntoIterator<Item = Point>,
5112    ) -> impl 'a + Iterator<Item = MBD>
5113    where
5114        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5115    {
5116        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5117        cursor.seek(&DimensionPair {
5118            key: Point::default(),
5119            value: None,
5120        });
5121        let mut points = points.into_iter();
5122        iter::from_fn(move || {
5123            let point = points.next()?;
5124
5125            cursor.seek_forward(&DimensionPair {
5126                key: point,
5127                value: None,
5128            });
5129
5130            if let Some(region) = cursor.region() {
5131                let overshoot = point - region.range.start.key;
5132                let buffer_point = region.buffer_range.start + overshoot;
5133                let mut position = region.range.start.value.unwrap();
5134                position.add_text_dim(
5135                    &region
5136                        .buffer
5137                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5138                );
5139                if point == region.range.end.key && region.has_trailing_newline {
5140                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5141                }
5142                Some(position)
5143            } else {
5144                Some(MBD::from_summary(&self.text_summary()))
5145            }
5146        })
5147    }
5148
5149    pub fn excerpts_for_buffer(
5150        &self,
5151        buffer_id: BufferId,
5152    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
5153        if let Some(buffer_state) = self.buffers.get(&buffer_id) {
5154            let path_key = buffer_state.path_key.clone();
5155            let mut cursor = self.excerpts.cursor::<PathKey>(());
5156            cursor.seek_forward(&path_key, Bias::Left);
5157            Some(iter::from_fn(move || {
5158                let excerpt = cursor.item()?;
5159                if excerpt.path_key != path_key {
5160                    return None;
5161                }
5162                cursor.next();
5163                Some(excerpt.range.clone())
5164            }))
5165        } else {
5166            None
5167        }
5168        .into_iter()
5169        .flatten()
5170    }
5171
5172    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5173        self.anchor_at(position, Bias::Left)
5174    }
5175
5176    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5177        self.anchor_at(position, Bias::Right)
5178    }
5179
5180    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5181        let offset = position.to_offset(self);
5182
5183        // Find the given position in the diff transforms. Determine the corresponding
5184        // offset in the excerpts, and whether the position is within a deleted hunk.
5185        let mut diff_transforms = self
5186            .diff_transforms
5187            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5188        diff_transforms.seek(&offset, Bias::Right);
5189
5190        if offset == diff_transforms.start().0
5191            && bias == Bias::Left
5192            && let Some(prev_item) = diff_transforms.prev_item()
5193            && let DiffTransform::DeletedHunk { .. } = prev_item
5194        {
5195            diff_transforms.prev();
5196        }
5197        let offset_in_transform = offset - diff_transforms.start().0;
5198        let mut excerpt_offset = diff_transforms.start().1;
5199        let mut diff_base_anchor = None;
5200        if let Some(DiffTransform::DeletedHunk {
5201            buffer_id,
5202            base_text_byte_range,
5203            has_trailing_newline,
5204            ..
5205        }) = diff_transforms.item()
5206        {
5207            let diff = self.diff_state(*buffer_id).expect("missing diff");
5208            if offset_in_transform > base_text_byte_range.len() {
5209                debug_assert!(*has_trailing_newline);
5210                bias = Bias::Right;
5211            } else {
5212                diff_base_anchor = Some(
5213                    diff.base_text()
5214                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5215                );
5216                bias = Bias::Left;
5217            }
5218        } else {
5219            excerpt_offset += MultiBufferOffset(offset_in_transform);
5220        };
5221
5222        let mut excerpts = self
5223            .excerpts
5224            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5225        excerpts.seek(&excerpt_offset, Bias::Right);
5226        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5227            excerpts.prev();
5228        }
5229        if let Some(excerpt) = excerpts.item() {
5230            let buffer_snapshot = excerpt.buffer_snapshot(self);
5231            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5232            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5233                overshoot -= 1;
5234                bias = Bias::Right;
5235            }
5236
5237            let buffer_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
5238            let text_anchor = excerpt.clip_anchor(
5239                buffer_snapshot.anchor_at(buffer_start + overshoot, bias),
5240                self,
5241            );
5242            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5243            let anchor = match diff_base_anchor {
5244                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5245                None => anchor,
5246            };
5247            anchor.into()
5248        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5249        {
5250            Anchor::Min
5251        } else {
5252            Anchor::Max
5253        }
5254    }
5255
5256    /// Lifts a buffer anchor to a multibuffer anchor without checking against excerpt boundaries. Returns `None` if there are no excerpts for the buffer
5257    pub fn anchor_in_buffer(&self, anchor: text::Anchor) -> Option<Anchor> {
5258        let path_key_index = self.path_key_index_for_buffer(anchor.buffer_id)?;
5259        Some(Anchor::in_buffer(path_key_index, anchor))
5260    }
5261
5262    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5263    pub fn anchor_in_excerpt(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5264        let excerpts = {
5265            let buffer_id = text_anchor.buffer_id;
5266            if let Some(buffer_state) = self.buffers.get(&buffer_id) {
5267                let path_key = buffer_state.path_key.clone();
5268                let mut cursor = self.excerpts.cursor::<PathKey>(());
5269                cursor.seek_forward(&path_key, Bias::Left);
5270                Some(iter::from_fn(move || {
5271                    let excerpt = cursor.item()?;
5272                    if excerpt.path_key != path_key {
5273                        return None;
5274                    }
5275                    cursor.next();
5276                    Some(excerpt)
5277                }))
5278            } else {
5279                None
5280            }
5281            .into_iter()
5282            .flatten()
5283        };
5284        for excerpt in excerpts {
5285            let buffer_snapshot = excerpt.buffer_snapshot(self);
5286            if excerpt.range.contains(&text_anchor, &buffer_snapshot) {
5287                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5288            }
5289        }
5290
5291        None
5292    }
5293
5294    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5295    pub fn buffer_anchor_range_to_anchor_range(
5296        &self,
5297        text_anchor: Range<text::Anchor>,
5298    ) -> Option<Range<Anchor>> {
5299        for excerpt in {
5300            let this = &self;
5301            let buffer_id = text_anchor.start.buffer_id;
5302            if let Some(buffer_state) = this.buffers.get(&buffer_id) {
5303                let path_key = buffer_state.path_key.clone();
5304                let mut cursor = this.excerpts.cursor::<PathKey>(());
5305                cursor.seek_forward(&path_key, Bias::Left);
5306                Some(iter::from_fn(move || {
5307                    let excerpt = cursor.item()?;
5308                    if excerpt.path_key != path_key {
5309                        return None;
5310                    }
5311                    cursor.next();
5312                    Some(excerpt)
5313                }))
5314            } else {
5315                None
5316            }
5317            .into_iter()
5318            .flatten()
5319        } {
5320            let buffer_snapshot = excerpt.buffer_snapshot(self);
5321            if excerpt.range.contains(&text_anchor.start, &buffer_snapshot)
5322                && excerpt.range.contains(&text_anchor.end, &buffer_snapshot)
5323            {
5324                return Some(Anchor::range_in_buffer(excerpt.path_key_index, text_anchor));
5325            }
5326        }
5327
5328        None
5329    }
5330
5331    /// Returns a buffer anchor and its buffer snapshot for the given anchor, if it is in the multibuffer.
5332    pub fn anchor_to_buffer_anchor(
5333        &self,
5334        anchor: Anchor,
5335    ) -> Option<(text::Anchor, &BufferSnapshot)> {
5336        match anchor {
5337            Anchor::Min => {
5338                let excerpt = self.excerpts.first()?;
5339                let buffer = excerpt.buffer_snapshot(self);
5340                Some((excerpt.range.context.start, buffer))
5341            }
5342            Anchor::Excerpt(excerpt_anchor) => {
5343                let buffer = self.buffer_for_id(excerpt_anchor.buffer_id())?;
5344                Some((excerpt_anchor.text_anchor, buffer))
5345            }
5346            Anchor::Max => {
5347                let excerpt = self.excerpts.last()?;
5348                let buffer = excerpt.buffer_snapshot(self);
5349                Some((excerpt.range.context.end, buffer))
5350            }
5351        }
5352    }
5353
5354    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5355        match anchor {
5356            // todo(lw): should be `!self.is_empty()`
5357            Anchor::Min | Anchor::Max => true,
5358            Anchor::Excerpt(excerpt_anchor) => {
5359                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5360                    return false;
5361                };
5362                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5363                cursor.seek(&target, Bias::Left);
5364                let Some(excerpt) = cursor.item() else {
5365                    return false;
5366                };
5367                excerpt
5368                    .buffer_snapshot(self)
5369                    .can_resolve(&excerpt_anchor.text_anchor())
5370            }
5371        }
5372    }
5373
5374    pub fn excerpts(&self) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
5375        self.excerpts.iter().map(|excerpt| excerpt.range.clone())
5376    }
5377
5378    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5379    where
5380        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5381        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5382    {
5383        let excerpts = self.excerpts.cursor(());
5384        let diff_transforms = self.diff_transforms.cursor(());
5385        MultiBufferCursor {
5386            excerpts,
5387            diff_transforms,
5388            cached_region: OnceCell::new(),
5389            snapshot: self,
5390        }
5391    }
5392
5393    pub fn excerpt_before(&self, anchor: Anchor) -> Option<ExcerptRange<text::Anchor>> {
5394        let target = anchor.try_seek_target(&self)?;
5395        let mut excerpts = self.excerpts.cursor::<ExcerptSummary>(());
5396        excerpts.seek(&target, Bias::Left);
5397        excerpts.prev();
5398        Some(excerpts.item()?.range.clone())
5399    }
5400
5401    pub fn excerpt_boundaries_in_range<R, T>(
5402        &self,
5403        range: R,
5404    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5405    where
5406        R: RangeBounds<T>,
5407        T: ToOffset,
5408    {
5409        let start_offset;
5410        let start = match range.start_bound() {
5411            Bound::Included(start) => {
5412                start_offset = start.to_offset(self);
5413                Bound::Included(start_offset)
5414            }
5415            Bound::Excluded(_) => {
5416                panic!("not supported")
5417            }
5418            Bound::Unbounded => {
5419                start_offset = MultiBufferOffset::ZERO;
5420                Bound::Unbounded
5421            }
5422        };
5423        let end = match range.end_bound() {
5424            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5425            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5426            Bound::Unbounded => Bound::Unbounded,
5427        };
5428        let bounds = (start, end);
5429        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5430        cursor.seek(&DimensionPair {
5431            key: start_offset,
5432            value: None,
5433        });
5434
5435        if cursor
5436            .fetch_excerpt_with_range()
5437            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5438        {
5439            cursor.prev_excerpt();
5440        } else {
5441            cursor.seek_to_start_of_current_excerpt();
5442        }
5443        let mut prev_excerpt = cursor
5444            .fetch_excerpt_with_range()
5445            .map(|(excerpt, _)| excerpt);
5446
5447        cursor.next_excerpt_forwards();
5448
5449        iter::from_fn(move || {
5450            loop {
5451                if self.singleton {
5452                    return None;
5453                }
5454
5455                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5456                cursor.next_excerpt_forwards();
5457                if !bounds.contains(&next_range.start.key) {
5458                    prev_excerpt = Some(next_excerpt);
5459                    continue;
5460                }
5461
5462                let next_region_start = next_range.start.value.unwrap();
5463                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5464                    range.start.value.unwrap()
5465                } else {
5466                    self.max_point()
5467                };
5468
5469                let prev = prev_excerpt.as_ref().map(|excerpt| ExcerptBoundaryInfo {
5470                    start_anchor: Anchor::in_buffer(
5471                        excerpt.path_key_index,
5472                        excerpt.range.context.start,
5473                    ),
5474                    range: excerpt.range.clone(),
5475                    end_row: MultiBufferRow(next_region_start.row),
5476                });
5477
5478                let next = ExcerptBoundaryInfo {
5479                    start_anchor: Anchor::in_buffer(
5480                        next_excerpt.path_key_index,
5481                        next_excerpt.range.context.start,
5482                    ),
5483                    range: next_excerpt.range.clone(),
5484                    end_row: if next_excerpt.has_trailing_newline {
5485                        MultiBufferRow(next_region_end.row - 1)
5486                    } else {
5487                        MultiBufferRow(next_region_end.row)
5488                    },
5489                };
5490
5491                let row = MultiBufferRow(next_region_start.row);
5492
5493                prev_excerpt = Some(next_excerpt);
5494
5495                return Some(ExcerptBoundary { row, prev, next });
5496            }
5497        })
5498    }
5499
5500    pub fn edit_count(&self) -> usize {
5501        self.edit_count
5502    }
5503
5504    pub fn non_text_state_update_count(&self) -> usize {
5505        self.non_text_state_update_count
5506    }
5507
5508    /// Allows converting several ranges within the same excerpt between buffer offsets and multibuffer offsets.
5509    ///
5510    /// If the input range is contained in a single excerpt, invokes the callback with the full range of that excerpt
5511    /// and the input range both converted to buffer coordinates. The buffer ranges returned by the callback are lifted back
5512    /// to multibuffer offsets and returned.
5513    ///
5514    /// Returns `None` if the input range spans multiple excerpts.
5515    pub fn map_excerpt_ranges<'a, T>(
5516        &'a self,
5517        position: Range<MultiBufferOffset>,
5518        f: impl FnOnce(
5519            &'a BufferSnapshot,
5520            ExcerptRange<BufferOffset>,
5521            Range<BufferOffset>,
5522        ) -> Vec<(Range<BufferOffset>, T)>,
5523    ) -> Option<Vec<(Range<MultiBufferOffset>, T)>> {
5524        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
5525        cursor.seek(&position.start);
5526
5527        let region = cursor.region()?;
5528        if !region.is_main_buffer {
5529            return None;
5530        }
5531        let excerpt = cursor.excerpt()?;
5532        let excerpt_start = *cursor.excerpts.start();
5533        let input_buffer_start = cursor.buffer_position_at(&position.start)?;
5534
5535        cursor.seek_forward(&position.end);
5536        if cursor.excerpt()? != excerpt {
5537            return None;
5538        }
5539        let region = cursor.region()?;
5540        if !region.is_main_buffer {
5541            return None;
5542        }
5543        let input_buffer_end = cursor.buffer_position_at(&position.end)?;
5544        let input_buffer_range = input_buffer_start..input_buffer_end;
5545        let buffer = excerpt.buffer_snapshot(self);
5546        let excerpt_context_range = excerpt.range.context.to_offset(buffer);
5547        let excerpt_context_range =
5548            BufferOffset(excerpt_context_range.start)..BufferOffset(excerpt_context_range.end);
5549        let excerpt_primary_range = excerpt.range.primary.to_offset(buffer);
5550        let excerpt_primary_range =
5551            BufferOffset(excerpt_primary_range.start)..BufferOffset(excerpt_primary_range.end);
5552        let results = f(
5553            buffer,
5554            ExcerptRange {
5555                context: excerpt_context_range.clone(),
5556                primary: excerpt_primary_range,
5557            },
5558            input_buffer_range,
5559        );
5560        let mut diff_transforms = cursor.diff_transforms;
5561        Some(
5562            results
5563                .into_iter()
5564                .map(|(buffer_range, metadata)| {
5565                    let clamped_start = buffer_range
5566                        .start
5567                        .max(excerpt_context_range.start)
5568                        .min(excerpt_context_range.end);
5569                    let clamped_end = buffer_range
5570                        .end
5571                        .max(clamped_start)
5572                        .min(excerpt_context_range.end);
5573                    let excerpt_offset_start =
5574                        excerpt_start + (clamped_start.0 - excerpt_context_range.start.0);
5575                    let excerpt_offset_end =
5576                        excerpt_start + (clamped_end.0 - excerpt_context_range.start.0);
5577
5578                    diff_transforms.seek(&excerpt_offset_start, Bias::Right);
5579                    let mut output_start = diff_transforms.start().output_dimension;
5580                    output_start +=
5581                        excerpt_offset_start - diff_transforms.start().excerpt_dimension;
5582
5583                    diff_transforms.seek_forward(&excerpt_offset_end, Bias::Right);
5584                    let mut output_end = diff_transforms.start().output_dimension;
5585                    output_end += excerpt_offset_end - diff_transforms.start().excerpt_dimension;
5586
5587                    (output_start.0..output_end.0, metadata)
5588                })
5589                .collect(),
5590        )
5591    }
5592
5593    /// Returns the smallest enclosing bracket ranges containing the given range or
5594    /// None if no brackets contain range or the range is not contained in a single
5595    /// excerpt
5596    ///
5597    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5598    #[ztracing::instrument(skip_all)]
5599    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5600        &self,
5601        range: Range<T>,
5602        range_filter: Option<
5603            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5604        >,
5605    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5606        let range = range.start.to_offset(self)..range.end.to_offset(self);
5607        let results =
5608            self.map_excerpt_ranges(range, |buffer, excerpt_range, input_buffer_range| {
5609                let filter = |open: Range<usize>, close: Range<usize>| -> bool {
5610                    excerpt_range.context.start.0 <= open.start
5611                        && close.end <= excerpt_range.context.end.0
5612                        && range_filter.is_none_or(|filter| {
5613                            filter(
5614                                buffer,
5615                                BufferOffset(open.start)..BufferOffset(close.end),
5616                                BufferOffset(close.start)..BufferOffset(close.end),
5617                            )
5618                        })
5619                };
5620                let Some((open, close)) =
5621                    buffer.innermost_enclosing_bracket_ranges(input_buffer_range, Some(&filter))
5622                else {
5623                    return Vec::new();
5624                };
5625                vec![
5626                    (BufferOffset(open.start)..BufferOffset(open.end), ()),
5627                    (BufferOffset(close.start)..BufferOffset(close.end), ()),
5628                ]
5629            })?;
5630        let [(open, _), (close, _)] = results.try_into().ok()?;
5631        Some((open, close))
5632    }
5633
5634    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5635    /// not contained in a single excerpt
5636    pub fn enclosing_bracket_ranges<T: ToOffset>(
5637        &self,
5638        range: Range<T>,
5639    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)>> {
5640        let range = range.start.to_offset(self)..range.end.to_offset(self);
5641        let results =
5642            self.map_excerpt_ranges(range, |buffer, excerpt_range, input_buffer_range| {
5643                buffer
5644                    .enclosing_bracket_ranges(input_buffer_range)
5645                    .filter(|pair| {
5646                        excerpt_range.context.start.0 <= pair.open_range.start
5647                            && pair.close_range.end <= excerpt_range.context.end.0
5648                    })
5649                    .flat_map(|pair| {
5650                        [
5651                            (
5652                                BufferOffset(pair.open_range.start)
5653                                    ..BufferOffset(pair.open_range.end),
5654                                (),
5655                            ),
5656                            (
5657                                BufferOffset(pair.close_range.start)
5658                                    ..BufferOffset(pair.close_range.end),
5659                                (),
5660                            ),
5661                        ]
5662                    })
5663                    .collect()
5664            })?;
5665        Some(results.into_iter().map(|(range, _)| range).tuples())
5666    }
5667
5668    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5669    /// not contained in a single excerpt
5670    pub fn text_object_ranges<T: ToOffset>(
5671        &self,
5672        range: Range<T>,
5673        options: TreeSitterOptions,
5674    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5675        let range = range.start.to_offset(self)..range.end.to_offset(self);
5676        self.map_excerpt_ranges(range, |buffer, excerpt_range, input_buffer_range| {
5677            buffer
5678                .text_object_ranges(input_buffer_range, options)
5679                .filter(|(range, _)| {
5680                    excerpt_range.context.start.0 <= range.start
5681                        && range.end <= excerpt_range.context.end.0
5682                })
5683                .map(|(range, text_object)| {
5684                    (
5685                        BufferOffset(range.start)..BufferOffset(range.end),
5686                        text_object,
5687                    )
5688                })
5689                .collect()
5690        })
5691        .into_iter()
5692        .flatten()
5693    }
5694
5695    pub fn bracket_ranges<T: ToOffset>(
5696        &self,
5697        range: Range<T>,
5698    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)>> {
5699        let range = range.start.to_offset(self)..range.end.to_offset(self);
5700        let results =
5701            self.map_excerpt_ranges(range, |buffer, excerpt_range, input_buffer_range| {
5702                buffer
5703                    .bracket_ranges(input_buffer_range)
5704                    .filter(|pair| {
5705                        excerpt_range.context.start.0 <= pair.open_range.start
5706                            && pair.close_range.end <= excerpt_range.context.end.0
5707                    })
5708                    .flat_map(|pair| {
5709                        [
5710                            (
5711                                BufferOffset(pair.open_range.start)
5712                                    ..BufferOffset(pair.open_range.end),
5713                                (),
5714                            ),
5715                            (
5716                                BufferOffset(pair.close_range.start)
5717                                    ..BufferOffset(pair.close_range.end),
5718                                (),
5719                            ),
5720                        ]
5721                    })
5722                    .collect()
5723            })?;
5724        Some(results.into_iter().map(|(range, _)| range).tuples())
5725    }
5726
5727    pub fn redacted_ranges<'a, T: ToOffset>(
5728        &'a self,
5729        range: Range<T>,
5730        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5731    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5732        let range = range.start.to_offset(self)..range.end.to_offset(self);
5733        self.lift_buffer_metadata(range, move |buffer, range| {
5734            if redaction_enabled(buffer.file()) {
5735                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5736            } else {
5737                None
5738            }
5739        })
5740        .map(|(range, _, _)| range)
5741    }
5742
5743    pub fn runnable_ranges(
5744        &self,
5745        range: Range<Anchor>,
5746    ) -> impl Iterator<Item = (Range<Anchor>, language::RunnableRange)> + '_ {
5747        let range = range.start.to_offset(self)..range.end.to_offset(self);
5748        self.lift_buffer_metadata(range, move |buffer, range| {
5749            Some(
5750                buffer
5751                    .runnable_ranges(range.clone())
5752                    .filter(move |runnable| {
5753                        runnable.run_range.start >= range.start
5754                            && runnable.run_range.end < range.end
5755                    })
5756                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5757            )
5758        })
5759        .map(|(run_range, runnable, _)| {
5760            (
5761                self.anchor_after(run_range.start)..self.anchor_before(run_range.end),
5762                runnable,
5763            )
5764        })
5765    }
5766
5767    pub fn line_indents(
5768        &self,
5769        start_row: MultiBufferRow,
5770        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5771    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5772        let max_point = self.max_point();
5773        let mut cursor = self.cursor::<Point, Point>();
5774        cursor.seek(&Point::new(start_row.0, 0));
5775        iter::from_fn(move || {
5776            let mut region = cursor.region()?;
5777            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5778                cursor.next();
5779                region = cursor.region()?;
5780            }
5781            let region = cursor.region()?;
5782            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5783            let buffer_start_row =
5784                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5785
5786            let buffer_end_row = if region.is_main_buffer
5787                && (region.has_trailing_newline || region.range.end == max_point)
5788            {
5789                region.buffer_range.end.row
5790            } else {
5791                region.buffer_range.end.row.saturating_sub(1)
5792            };
5793
5794            let line_indents = region
5795                .buffer
5796                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5797            let region_buffer_row = region.buffer_range.start.row;
5798            let region_row = region.range.start.row;
5799            let region_buffer = region.excerpt.buffer_snapshot(self);
5800            cursor.next();
5801            Some(line_indents.map(move |(buffer_row, indent)| {
5802                let row = region_row + (buffer_row - region_buffer_row);
5803                (MultiBufferRow(row), indent, region_buffer)
5804            }))
5805        })
5806        .flatten()
5807    }
5808
5809    pub fn reversed_line_indents(
5810        &self,
5811        end_row: MultiBufferRow,
5812        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5813    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5814        let max_point = self.max_point();
5815        let mut cursor = self.cursor::<Point, Point>();
5816        cursor.seek(&Point::new(end_row.0, 0));
5817        iter::from_fn(move || {
5818            let mut region = cursor.region()?;
5819            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5820                cursor.prev();
5821                region = cursor.region()?;
5822            }
5823            let region = cursor.region()?;
5824
5825            let buffer_start_row = region.buffer_range.start.row;
5826            let buffer_end_row = if region.is_main_buffer
5827                && (region.has_trailing_newline || region.range.end == max_point)
5828            {
5829                region.buffer_range.end.row + 1
5830            } else {
5831                region.buffer_range.end.row
5832            };
5833
5834            let overshoot = end_row.0 - region.range.start.row;
5835            let buffer_end_row =
5836                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5837
5838            let line_indents = region
5839                .buffer
5840                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5841            let region_buffer_row = region.buffer_range.start.row;
5842            let region_row = region.range.start.row;
5843            let region_buffer = region.excerpt.buffer_snapshot(self);
5844            cursor.prev();
5845            Some(line_indents.map(move |(buffer_row, indent)| {
5846                let row = region_row + (buffer_row - region_buffer_row);
5847                (MultiBufferRow(row), indent, region_buffer)
5848            }))
5849        })
5850        .flatten()
5851    }
5852
5853    pub async fn enclosing_indent(
5854        &self,
5855        mut target_row: MultiBufferRow,
5856    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5857        let max_row = MultiBufferRow(self.max_point().row);
5858        if target_row >= max_row {
5859            return None;
5860        }
5861
5862        let mut target_indent = self.line_indent_for_row(target_row);
5863
5864        // If the current row is at the start of an indented block, we want to return this
5865        // block as the enclosing indent.
5866        if !target_indent.is_line_empty() && target_row < max_row {
5867            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5868            if !next_line_indent.is_line_empty()
5869                && target_indent.raw_len() < next_line_indent.raw_len()
5870            {
5871                target_indent = next_line_indent;
5872                target_row.0 += 1;
5873            }
5874        }
5875
5876        const SEARCH_ROW_LIMIT: u32 = 25000;
5877        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5878        const YIELD_INTERVAL: u32 = 100;
5879
5880        let mut accessed_row_counter = 0;
5881
5882        // If there is a blank line at the current row, search for the next non indented lines
5883        if target_indent.is_line_empty() {
5884            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5885            let end =
5886                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5887
5888            let mut non_empty_line_above = None;
5889            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5890                if row < start {
5891                    break;
5892                }
5893                accessed_row_counter += 1;
5894                if accessed_row_counter == YIELD_INTERVAL {
5895                    accessed_row_counter = 0;
5896                    yield_now().await;
5897                }
5898                if !indent.is_line_empty() {
5899                    non_empty_line_above = Some((row, indent));
5900                    break;
5901                }
5902            }
5903
5904            let mut non_empty_line_below = None;
5905            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5906                if row > end {
5907                    break;
5908                }
5909                accessed_row_counter += 1;
5910                if accessed_row_counter == YIELD_INTERVAL {
5911                    accessed_row_counter = 0;
5912                    yield_now().await;
5913                }
5914                if !indent.is_line_empty() {
5915                    non_empty_line_below = Some((row, indent));
5916                    break;
5917                }
5918            }
5919
5920            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5921                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5922                    if above_indent.raw_len() >= below_indent.raw_len() {
5923                        (above_row, above_indent)
5924                    } else {
5925                        (below_row, below_indent)
5926                    }
5927                }
5928                (Some(above), None) => above,
5929                (None, Some(below)) => below,
5930                _ => return None,
5931            };
5932
5933            target_indent = indent;
5934            target_row = row;
5935        }
5936
5937        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5938        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5939
5940        let mut start_indent = None;
5941        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5942            if row < start {
5943                break;
5944            }
5945            accessed_row_counter += 1;
5946            if accessed_row_counter == YIELD_INTERVAL {
5947                accessed_row_counter = 0;
5948                yield_now().await;
5949            }
5950            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5951                start_indent = Some((row, indent));
5952                break;
5953            }
5954        }
5955        let (start_row, start_indent_size) = start_indent?;
5956
5957        let mut end_indent = (end, None);
5958        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5959            if row > end {
5960                break;
5961            }
5962            accessed_row_counter += 1;
5963            if accessed_row_counter == YIELD_INTERVAL {
5964                accessed_row_counter = 0;
5965                yield_now().await;
5966            }
5967            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5968                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5969                break;
5970            }
5971        }
5972        let (end_row, end_indent_size) = end_indent;
5973
5974        let indent = if let Some(end_indent_size) = end_indent_size {
5975            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5976                start_indent_size
5977            } else {
5978                end_indent_size
5979            }
5980        } else {
5981            start_indent_size
5982        };
5983
5984        Some((start_row..end_row, indent))
5985    }
5986
5987    pub fn indent_guides_in_range<T: ToPoint>(
5988        &self,
5989        range: Range<T>,
5990        ignore_disabled_for_language: bool,
5991        cx: &App,
5992    ) -> impl Iterator<Item = IndentGuide> {
5993        let range = range.start.to_point(self)..range.end.to_point(self);
5994        let start_row = MultiBufferRow(range.start.row);
5995        let end_row = MultiBufferRow(range.end.row);
5996
5997        let mut row_indents = self.line_indents(start_row, |buffer| {
5998            let settings = LanguageSettings::for_buffer_snapshot(buffer, None, cx);
5999            settings.indent_guides.enabled || ignore_disabled_for_language
6000        });
6001
6002        let mut result = Vec::new();
6003        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6004
6005        let mut prev_settings = None;
6006        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6007            if first_row > end_row {
6008                break;
6009            }
6010            let current_depth = indent_stack.len() as u32;
6011
6012            // Avoid retrieving the language settings repeatedly for every buffer row.
6013            if let Some((prev_buffer_id, _)) = &prev_settings
6014                && prev_buffer_id != &buffer.remote_id()
6015            {
6016                prev_settings.take();
6017            }
6018            let settings = &prev_settings
6019                .get_or_insert_with(|| {
6020                    (
6021                        buffer.remote_id(),
6022                        LanguageSettings::for_buffer_snapshot(buffer, None, cx),
6023                    )
6024                })
6025                .1;
6026            let tab_size = settings.tab_size.get();
6027
6028            // When encountering empty, continue until found useful line indent
6029            // then add to the indent stack with the depth found
6030            let mut found_indent = false;
6031            let mut last_row = first_row;
6032            if line_indent.is_line_blank() {
6033                while !found_indent {
6034                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6035                        break;
6036                    };
6037                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6038                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6039                        break;
6040                    }
6041
6042                    if new_line_indent.is_line_blank() {
6043                        continue;
6044                    }
6045                    last_row = target_row.min(end_row);
6046                    line_indent = new_line_indent;
6047                    found_indent = true;
6048                    break;
6049                }
6050            } else {
6051                found_indent = true
6052            }
6053
6054            let depth = if found_indent {
6055                line_indent.len(tab_size) / tab_size
6056            } else {
6057                0
6058            };
6059
6060            match depth.cmp(&current_depth) {
6061                cmp::Ordering::Less => {
6062                    for _ in 0..(current_depth - depth) {
6063                        let mut indent = indent_stack.pop().unwrap();
6064                        if last_row != first_row {
6065                            // In this case, we landed on an empty row, had to seek forward,
6066                            // and discovered that the indent we where on is ending.
6067                            // This means that the last display row must
6068                            // be on line that ends this indent range, so we
6069                            // should display the range up to the first non-empty line
6070                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6071                        }
6072
6073                        result.push(indent)
6074                    }
6075                }
6076                cmp::Ordering::Greater => {
6077                    for next_depth in current_depth..depth {
6078                        indent_stack.push(IndentGuide {
6079                            buffer_id: buffer.remote_id(),
6080                            start_row: first_row,
6081                            end_row: last_row,
6082                            depth: next_depth,
6083                            tab_size,
6084                            settings: settings.indent_guides.clone(),
6085                        });
6086                    }
6087                }
6088                _ => {}
6089            }
6090
6091            for indent in indent_stack.iter_mut() {
6092                indent.end_row = last_row;
6093            }
6094        }
6095
6096        result.extend(indent_stack);
6097        result.into_iter()
6098    }
6099
6100    pub fn trailing_excerpt_update_count(&self) -> usize {
6101        self.trailing_excerpt_update_count
6102    }
6103
6104    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6105        self.point_to_buffer_offset(point)
6106            .and_then(|(buffer, _)| buffer.file())
6107    }
6108
6109    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6110        self.point_to_buffer_offset(offset)
6111            .and_then(|(buffer, offset)| buffer.language_at(offset))
6112    }
6113
6114    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6115        self.excerpts
6116            .first()
6117            .map(|excerpt| excerpt.buffer_snapshot(self))
6118            .map(|buffer| LanguageSettings::for_buffer_snapshot(buffer, None, cx))
6119            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6120    }
6121
6122    pub fn language_settings_at<'a, T: ToOffset>(
6123        &'a self,
6124        point: T,
6125        cx: &'a App,
6126    ) -> Cow<'a, LanguageSettings> {
6127        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6128            buffer.settings_at(offset, cx)
6129        } else {
6130            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
6131        }
6132    }
6133
6134    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6135        self.point_to_buffer_offset(point)
6136            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6137    }
6138
6139    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6140        self.point_to_buffer_offset(point)
6141            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6142            .unwrap_or_default()
6143    }
6144
6145    pub fn language_indent_size_at<T: ToOffset>(
6146        &self,
6147        position: T,
6148        cx: &App,
6149    ) -> Option<IndentSize> {
6150        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6151        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6152    }
6153
6154    pub fn is_dirty(&self) -> bool {
6155        self.is_dirty
6156    }
6157
6158    pub fn has_deleted_file(&self) -> bool {
6159        self.has_deleted_file
6160    }
6161
6162    pub fn has_conflict(&self) -> bool {
6163        self.has_conflict
6164    }
6165
6166    pub fn has_diagnostics(&self) -> bool {
6167        self.excerpts
6168            .iter()
6169            .any(|excerpt| excerpt.buffer_snapshot(self).has_diagnostics())
6170    }
6171
6172    pub fn diagnostic_group(
6173        &self,
6174        buffer_id: BufferId,
6175        group_id: usize,
6176    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6177        self.lift_buffer_metadata::<Point, _, _>(
6178            Point::zero()..self.max_point(),
6179            move |buffer, range| {
6180                if buffer.remote_id() != buffer_id {
6181                    return None;
6182                };
6183                Some(
6184                    buffer
6185                        .diagnostics_in_range(range, false)
6186                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6187                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6188                )
6189            },
6190        )
6191        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6192    }
6193
6194    pub fn diagnostics_in_range<'a, MBD>(
6195        &'a self,
6196        range: Range<MBD>,
6197    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6198    where
6199        MBD::TextDimension: 'a
6200            + text::ToOffset
6201            + text::FromAnchor
6202            + Sub<Output = MBD::TextDimension>
6203            + fmt::Debug
6204            + ops::Add<Output = MBD::TextDimension>
6205            + ops::AddAssign
6206            + Ord,
6207        MBD: MultiBufferDimension
6208            + Ord
6209            + Sub<Output = MBD::TextDimension>
6210            + ops::Add<MBD::TextDimension, Output = MBD>
6211            + ops::AddAssign<MBD::TextDimension>
6212            + 'a,
6213    {
6214        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6215            Some(
6216                buffer
6217                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6218                    .map(|entry| (entry.range, entry.diagnostic)),
6219            )
6220        })
6221        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6222    }
6223
6224    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6225        &'a self,
6226        range: Range<MBD>,
6227    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6228    where
6229        MBD: MultiBufferDimension
6230            + Ord
6231            + Sub<Output = MBD::TextDimension>
6232            + ops::Add<MBD::TextDimension, Output = MBD>
6233            + ops::AddAssign<MBD::TextDimension>,
6234        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6235            + ops::Add<Output = MBD::TextDimension>
6236            + text::ToOffset
6237            + text::FromAnchor
6238            + AddAssign<MBD::TextDimension>
6239            + Ord,
6240    {
6241        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6242            Some(
6243                buffer
6244                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6245                    .map(|entry| (entry.range, entry.diagnostic)),
6246            )
6247        })
6248        .map(|(range, diagnostic, excerpt)| {
6249            (
6250                excerpt.buffer_snapshot(self).remote_id(),
6251                DiagnosticEntryRef { diagnostic, range },
6252            )
6253        })
6254    }
6255
6256    pub fn syntax_ancestor<T: ToOffset>(
6257        &self,
6258        range: Range<T>,
6259    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6260        let range = range.start.to_offset(self)..range.end.to_offset(self);
6261        let results =
6262            self.map_excerpt_ranges(range, |buffer, excerpt_range, input_buffer_range| {
6263                let Some(node) = buffer.syntax_ancestor(input_buffer_range) else {
6264                    return vec![];
6265                };
6266                let node_range = node.byte_range();
6267                if excerpt_range.context.start.0 <= node_range.start
6268                    && node_range.end <= excerpt_range.context.end.0
6269                {
6270                    vec![(
6271                        BufferOffset(node_range.start)..BufferOffset(node_range.end),
6272                        node,
6273                    )]
6274                } else {
6275                    vec![]
6276                }
6277            })?;
6278        let (output_range, node) = results.into_iter().next()?;
6279        Some((node, output_range))
6280    }
6281
6282    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6283        let buffer_snapshot = self.as_singleton()?;
6284        let excerpt = self.excerpts.first()?;
6285        let path_key_index = excerpt.path_key_index;
6286        let outline = buffer_snapshot.outline(theme);
6287        Some(Outline::new(
6288            outline
6289                .items
6290                .into_iter()
6291                .map(|item| OutlineItem {
6292                    depth: item.depth,
6293                    range: Anchor::range_in_buffer(path_key_index, item.range),
6294                    source_range_for_text: Anchor::range_in_buffer(
6295                        path_key_index,
6296                        item.source_range_for_text,
6297                    ),
6298                    text: item.text,
6299                    highlight_ranges: item.highlight_ranges,
6300                    name_ranges: item.name_ranges,
6301                    body_range: item
6302                        .body_range
6303                        .map(|body_range| Anchor::range_in_buffer(path_key_index, body_range)),
6304                    annotation_range: item.annotation_range.map(|annotation_range| {
6305                        Anchor::range_in_buffer(path_key_index, annotation_range)
6306                    }),
6307                })
6308                .collect(),
6309        ))
6310    }
6311
6312    pub fn symbols_containing<T: ToOffset>(
6313        &self,
6314        offset: T,
6315        theme: Option<&SyntaxTheme>,
6316    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6317        let anchor = self.anchor_before(offset);
6318        let target = anchor.try_seek_target(&self)?;
6319        let (_, _, excerpt) = self.excerpts.find((), &target, Bias::Left);
6320        let excerpt = excerpt?;
6321        let buffer_snapshot = excerpt.buffer_snapshot(self);
6322        Some((
6323            buffer_snapshot.remote_id(),
6324            buffer_snapshot
6325                .symbols_containing(
6326                    anchor
6327                        .excerpt_anchor()
6328                        .map(|anchor| anchor.text_anchor())
6329                        .unwrap_or(text::Anchor::min_for_buffer(buffer_snapshot.remote_id())),
6330                    theme,
6331                )
6332                .into_iter()
6333                .flat_map(|item| {
6334                    Some(OutlineItem {
6335                        depth: item.depth,
6336                        source_range_for_text: Anchor::range_in_buffer(
6337                            excerpt.path_key_index,
6338                            item.source_range_for_text,
6339                        ),
6340                        range: Anchor::range_in_buffer(excerpt.path_key_index, item.range),
6341                        text: item.text,
6342                        highlight_ranges: item.highlight_ranges,
6343                        name_ranges: item.name_ranges,
6344                        body_range: item.body_range.map(|body_range| {
6345                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6346                        }),
6347                        annotation_range: item.annotation_range.map(|body_range| {
6348                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6349                        }),
6350                    })
6351                })
6352                .collect(),
6353        ))
6354    }
6355
6356    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6357        Some(&self.buffers.get(&buffer_id)?.path_key)
6358    }
6359
6360    pub(crate) fn path_key_index_for_buffer(&self, buffer_id: BufferId) -> Option<PathKeyIndex> {
6361        let snapshot = self.buffers.get(&buffer_id)?;
6362        Some(snapshot.path_key_index)
6363    }
6364
6365    fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6366        let path_key = &self.buffers.get(&buffer_id)?.path_key;
6367        self.first_excerpt_for_path(path_key)
6368    }
6369
6370    fn first_excerpt_for_path(&self, path_key: &PathKey) -> Option<&Excerpt> {
6371        let (_, _, first_excerpt) = self.excerpts.find::<PathKey, _>((), path_key, Bias::Left);
6372        first_excerpt
6373    }
6374
6375    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6376        self.buffers.get(&id).map(|state| &state.buffer_snapshot)
6377    }
6378
6379    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<&PathKey> {
6380        self.path_keys.get_index(anchor.path.0 as usize)
6381    }
6382
6383    pub fn path_for_anchor(&self, anchor: ExcerptAnchor) -> &PathKey {
6384        self.try_path_for_anchor(anchor)
6385            .expect("invalid anchor: path was never added to multibuffer")
6386    }
6387
6388    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6389    pub fn excerpt_containing<T: ToOffset>(
6390        &self,
6391        range: Range<T>,
6392    ) -> Option<(&BufferSnapshot, ExcerptRange<text::Anchor>)> {
6393        let range = range.start.to_offset(self)..range.end.to_offset(self);
6394        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6395        cursor.seek(&range.start);
6396
6397        let start_excerpt = cursor.excerpt()?;
6398        if range.end != range.start {
6399            cursor.seek_forward(&range.end);
6400            if cursor.excerpt()? != start_excerpt {
6401                return None;
6402            }
6403        }
6404
6405        Some((
6406            start_excerpt.buffer_snapshot(self),
6407            start_excerpt.range.clone(),
6408        ))
6409    }
6410
6411    pub fn selections_in_range<'a>(
6412        &'a self,
6413        range: &'a Range<Anchor>,
6414        include_local: bool,
6415    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6416        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6417        cursor.seek(&range.start.seek_target(self), Bias::Left);
6418        cursor
6419            .take_while(move |excerpt| {
6420                let excerpt_start =
6421                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6422                excerpt_start.cmp(&range.end, self).is_le()
6423            })
6424            .flat_map(move |excerpt| {
6425                let buffer_snapshot = excerpt.buffer_snapshot(self);
6426                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6427                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6428                    && excerpt.contains(&excerpt_anchor, self)
6429                {
6430                    query_range.start = excerpt_anchor.text_anchor();
6431                }
6432                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6433                    && excerpt.contains(&excerpt_anchor, self)
6434                {
6435                    query_range.end = excerpt_anchor.text_anchor();
6436                }
6437
6438                buffer_snapshot
6439                    .selections_in_range(query_range, include_local)
6440                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6441                        selections.map(move |selection| {
6442                            let mut start =
6443                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6444                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6445                            if range.start.cmp(&start, self).is_gt() {
6446                                start = range.start;
6447                            }
6448                            if range.end.cmp(&end, self).is_lt() {
6449                                end = range.end;
6450                            }
6451
6452                            (
6453                                replica_id,
6454                                line_mode,
6455                                cursor_shape,
6456                                Selection {
6457                                    id: selection.id,
6458                                    start,
6459                                    end,
6460                                    reversed: selection.reversed,
6461                                    goal: selection.goal,
6462                                },
6463                            )
6464                        })
6465                    })
6466            })
6467    }
6468
6469    pub fn show_headers(&self) -> bool {
6470        self.show_headers
6471    }
6472
6473    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6474        self.diff_state(buffer_id).map(|diff| &diff.diff)
6475    }
6476
6477    fn diff_state(&self, buffer_id: BufferId) -> Option<&DiffStateSnapshot> {
6478        find_diff_state(&self.diffs, buffer_id)
6479    }
6480
6481    pub fn total_changed_lines(&self) -> (u32, u32) {
6482        let summary = self.diffs.summary();
6483        (summary.added_rows, summary.removed_rows)
6484    }
6485
6486    pub fn all_diff_hunks_expanded(&self) -> bool {
6487        self.all_diff_hunks_expanded
6488    }
6489
6490    /// Visually annotates a position or range with the `Debug` representation of a value. The
6491    /// callsite of this function is used as a key - previous annotations will be removed.
6492    #[cfg(debug_assertions)]
6493    #[track_caller]
6494    pub fn debug<V, R>(&self, ranges: &R, value: V)
6495    where
6496        R: debug::ToMultiBufferDebugRanges,
6497        V: std::fmt::Debug,
6498    {
6499        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6500    }
6501
6502    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6503    /// debug annotations with the same key will be removed. The key is also used to determine the
6504    /// annotation's color.
6505    #[cfg(debug_assertions)]
6506    #[track_caller]
6507    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6508    where
6509        K: std::hash::Hash + 'static,
6510        R: debug::ToMultiBufferDebugRanges,
6511        V: std::fmt::Debug,
6512    {
6513        let text_ranges = ranges
6514            .to_multi_buffer_debug_ranges(self)
6515            .into_iter()
6516            .flat_map(|range| {
6517                self.range_to_buffer_ranges(range)
6518                    .into_iter()
6519                    .map(|(buffer_snapshot, range, _)| {
6520                        buffer_snapshot.anchor_after(range.start)
6521                            ..buffer_snapshot.anchor_before(range.end)
6522                    })
6523            })
6524            .collect();
6525        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6526            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6527        });
6528    }
6529
6530    fn excerpt_edits_for_diff_change(
6531        &self,
6532        path: &PathKey,
6533        diff_change_range: Range<usize>,
6534    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6535        let mut excerpt_edits = Vec::new();
6536        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6537        cursor.seek(path, Bias::Left);
6538        while let Some(excerpt) = cursor.item()
6539            && &excerpt.path_key == path
6540        {
6541            let buffer_snapshot = excerpt.buffer_snapshot(self);
6542            let excerpt_buffer_range = excerpt.range.context.to_offset(buffer_snapshot);
6543            let excerpt_start = cursor.start().clone();
6544            let excerpt_len = excerpt.text_summary.len;
6545            cursor.next();
6546            if diff_change_range.end < excerpt_buffer_range.start
6547                || diff_change_range.start > excerpt_buffer_range.end
6548            {
6549                continue;
6550            }
6551            let diff_change_start_in_excerpt = diff_change_range
6552                .start
6553                .saturating_sub(excerpt_buffer_range.start);
6554            let diff_change_end_in_excerpt = diff_change_range
6555                .end
6556                .saturating_sub(excerpt_buffer_range.start);
6557            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6558            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6559            excerpt_edits.push(Edit {
6560                old: edit_start..edit_end,
6561                new: edit_start..edit_end,
6562            });
6563        }
6564        excerpt_edits
6565    }
6566
6567    fn excerpts_for_path<'a>(
6568        &'a self,
6569        path_key: &'a PathKey,
6570    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> + 'a {
6571        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6572        cursor.seek(path_key, Bias::Left);
6573        cursor
6574            .take_while(move |item| &item.path_key == path_key)
6575            .map(|excerpt| excerpt.range.clone())
6576    }
6577
6578    /// If the given multibuffer range is contained in a single excerpt and contains no deleted hunks,
6579    /// returns the corresponding buffer range.
6580    ///
6581    /// Otherwise, returns None.
6582    pub fn range_to_buffer_range<MBD>(
6583        &self,
6584        range: Range<MBD>,
6585    ) -> Option<(&BufferSnapshot, Range<MBD::TextDimension>)>
6586    where
6587        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6588        MBD::TextDimension: AddAssign<<MBD as Sub>::Output>,
6589    {
6590        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
6591        cursor.seek(&range.start);
6592
6593        let start_region = cursor.region()?.clone();
6594
6595        while let Some(region) = cursor.region()
6596            && region.range.end < range.end
6597        {
6598            if !region.is_main_buffer {
6599                return None;
6600            }
6601            cursor.next();
6602        }
6603
6604        let end_region = cursor.region()?;
6605        if end_region.buffer.remote_id() != start_region.buffer.remote_id() {
6606            return None;
6607        }
6608
6609        let mut buffer_start = start_region.buffer_range.start;
6610        buffer_start += range.start - start_region.range.start;
6611        let mut buffer_end = end_region.buffer_range.start;
6612        buffer_end += range.end - end_region.range.start;
6613
6614        Some((start_region.buffer, buffer_start..buffer_end))
6615    }
6616
6617    /// If the two endpoints of the range lie in the same excerpt, return the corresponding
6618    /// buffer range. Intervening deleted hunks are allowed.
6619    pub fn anchor_range_to_buffer_anchor_range(
6620        &self,
6621        range: Range<Anchor>,
6622    ) -> Option<(&BufferSnapshot, Range<text::Anchor>)> {
6623        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6624        cursor.seek(&range.start.seek_target(&self), Bias::Left);
6625
6626        let start_excerpt = cursor.item()?;
6627
6628        let snapshot = start_excerpt.buffer_snapshot(&self);
6629
6630        cursor.seek(&range.end.seek_target(&self), Bias::Left);
6631
6632        let end_excerpt = cursor.item()?;
6633
6634        if start_excerpt != end_excerpt {
6635            return None;
6636        }
6637
6638        if let Anchor::Excerpt(excerpt_anchor) = range.start
6639            && (excerpt_anchor.path != start_excerpt.path_key_index
6640                || excerpt_anchor.buffer_id() != snapshot.remote_id())
6641        {
6642            return None;
6643        }
6644        if let Anchor::Excerpt(excerpt_anchor) = range.end
6645            && (excerpt_anchor.path != end_excerpt.path_key_index
6646                || excerpt_anchor.buffer_id() != snapshot.remote_id())
6647        {
6648            return None;
6649        }
6650
6651        Some((
6652            snapshot,
6653            range.start.text_anchor_in(snapshot)..range.end.text_anchor_in(snapshot),
6654        ))
6655    }
6656
6657    /// Returns all nonempty intersections of the given buffer range with excerpts in the multibuffer in order.
6658    ///
6659    /// The multibuffer ranges are split to not intersect deleted hunks.
6660    pub fn buffer_range_to_excerpt_ranges(
6661        &self,
6662        range: Range<text::Anchor>,
6663    ) -> impl Iterator<Item = Range<Anchor>> {
6664        assert!(range.start.buffer_id == range.end.buffer_id);
6665
6666        let buffer_id = range.start.buffer_id;
6667        self.buffers
6668            .get(&buffer_id)
6669            .map(|buffer_state_snapshot| {
6670                let path_key_index = buffer_state_snapshot.path_key_index;
6671                let buffer_snapshot = &buffer_state_snapshot.buffer_snapshot;
6672                let buffer_range = range.to_offset(buffer_snapshot);
6673
6674                let start = Anchor::in_buffer(path_key_index, range.start).to_offset(self);
6675                let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6676                cursor.seek(&start);
6677                std::iter::from_fn(move || {
6678                    while let Some(region) = cursor.region()
6679                        && !region.is_main_buffer
6680                    {
6681                        cursor.next();
6682                    }
6683
6684                    let region = cursor.region()?;
6685                    if region.buffer.remote_id() != buffer_id
6686                        || region.buffer_range.start > BufferOffset(buffer_range.end)
6687                    {
6688                        return None;
6689                    }
6690
6691                    let start = region
6692                        .buffer_range
6693                        .start
6694                        .max(BufferOffset(buffer_range.start));
6695                    let mut end = region.buffer_range.end.min(BufferOffset(buffer_range.end));
6696
6697                    cursor.next();
6698                    while let Some(region) = cursor.region()
6699                        && region.is_main_buffer
6700                        && region.buffer.remote_id() == buffer_id
6701                        && region.buffer_range.start <= end
6702                    {
6703                        end = end
6704                            .max(region.buffer_range.end)
6705                            .min(BufferOffset(buffer_range.end));
6706                        cursor.next();
6707                    }
6708
6709                    let multibuffer_range = Anchor::range_in_buffer(
6710                        path_key_index,
6711                        buffer_snapshot.anchor_range_inside(start..end),
6712                    );
6713                    Some(multibuffer_range)
6714                })
6715            })
6716            .into_iter()
6717            .flatten()
6718    }
6719
6720    pub fn buffers_with_paths<'a>(
6721        &'a self,
6722    ) -> impl 'a + Iterator<Item = (&'a BufferSnapshot, &'a PathKey)> {
6723        self.buffers
6724            .values()
6725            .map(|buffer| (&buffer.buffer_snapshot, &buffer.path_key))
6726    }
6727
6728    /// Returns the number of graphemes in `range`.
6729    ///
6730    /// This counts user-visible characters like `e\u{301}` as one.
6731    pub fn grapheme_count_for_range(&self, range: &Range<MultiBufferOffset>) -> usize {
6732        self.text_for_range(range.clone())
6733            .collect::<String>()
6734            .graphemes(true)
6735            .count()
6736    }
6737
6738    pub fn range_for_buffer(&self, buffer_id: BufferId) -> Option<Range<Point>> {
6739        let path_key = self.path_key_index_for_buffer(buffer_id)?;
6740        let start = Anchor::in_buffer(path_key, text::Anchor::min_for_buffer(buffer_id));
6741        let end = Anchor::in_buffer(path_key, text::Anchor::max_for_buffer(buffer_id));
6742        Some((start..end).to_point(self))
6743    }
6744}
6745
6746#[cfg(any(test, feature = "test-support"))]
6747impl MultiBufferSnapshot {
6748    pub fn random_byte_range(
6749        &self,
6750        start_offset: MultiBufferOffset,
6751        rng: &mut impl rand::Rng,
6752    ) -> Range<MultiBufferOffset> {
6753        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6754        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6755        start..end
6756    }
6757
6758    #[cfg(any(test, feature = "test-support"))]
6759    fn check_invariants(&self) {
6760        let excerpts = self.excerpts.items(());
6761
6762        let mut all_buffer_path_keys = HashSet::default();
6763        for buffer in self.buffers.values() {
6764            let path_key = buffer.path_key.clone();
6765            assert!(
6766                all_buffer_path_keys.insert(path_key),
6767                "path key reused for multiple buffers: {:#?}",
6768                self.buffers
6769            );
6770        }
6771
6772        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6773
6774        for (ix, excerpt) in excerpts.iter().enumerate() {
6775            if ix > 0 {
6776                let prev = &excerpts[ix - 1];
6777
6778                if excerpt.path_key < prev.path_key {
6779                    panic!("excerpt path_keys are out-of-order: {:#?}", excerpts);
6780                } else if excerpt.path_key == prev.path_key {
6781                    assert_eq!(
6782                        excerpt.buffer_id, prev.buffer_id,
6783                        "excerpts with same path_key have different buffer_ids: {:#?}",
6784                        excerpts
6785                    );
6786                    if excerpt
6787                        .start_anchor()
6788                        .cmp(&prev.end_anchor(), &self)
6789                        .is_le()
6790                    {
6791                        panic!("excerpt anchors are out-of-order: {:#?}", excerpts);
6792                    }
6793                    if excerpt
6794                        .start_anchor()
6795                        .cmp(&excerpt.end_anchor(), &self)
6796                        .is_ge()
6797                    {
6798                        panic!("excerpt with backward range: {:#?}", excerpts);
6799                    }
6800                }
6801            }
6802
6803            if ix < excerpts.len() - 1 {
6804                assert!(
6805                    excerpt.has_trailing_newline,
6806                    "non-trailing excerpt has no trailing newline: {:#?}",
6807                    excerpts
6808                );
6809            } else {
6810                assert!(
6811                    !excerpt.has_trailing_newline,
6812                    "trailing excerpt has trailing newline: {:#?}",
6813                    excerpts
6814                );
6815            }
6816            assert!(
6817                all_buffer_path_keys.contains(&excerpt.path_key),
6818                "excerpt path key not found in active path keys: {:#?}",
6819                excerpt.path_key
6820            );
6821            assert_eq!(
6822                self.path_keys.get_index(excerpt.path_key_index.0 as usize),
6823                Some(&excerpt.path_key),
6824                "excerpt path key index does not match path key: {:#?}",
6825                excerpt.path_key,
6826            );
6827        }
6828        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6829
6830        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6831            panic!(
6832                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6833                self.excerpts.summary().text,
6834                self.diff_transforms.summary().input,
6835                self.diff_transforms.items(()),
6836            );
6837        }
6838
6839        let mut prev_transform: Option<&DiffTransform> = None;
6840        for item in self.diff_transforms.iter() {
6841            if let DiffTransform::BufferContent {
6842                summary,
6843                inserted_hunk_info,
6844            } = item
6845            {
6846                if let Some(DiffTransform::BufferContent {
6847                    inserted_hunk_info: prev_inserted_hunk_info,
6848                    ..
6849                }) = prev_transform
6850                    && *inserted_hunk_info == *prev_inserted_hunk_info
6851                {
6852                    panic!(
6853                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6854                        self.diff_transforms.items(())
6855                    );
6856                }
6857                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6858                    panic!("empty buffer content transform");
6859                }
6860            }
6861            prev_transform = Some(item);
6862        }
6863    }
6864}
6865
6866impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6867where
6868    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6869    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6870{
6871    #[instrument(skip_all)]
6872    fn seek(&mut self, position: &MBD) {
6873        let position = OutputDimension(*position);
6874        self.cached_region.take();
6875        self.diff_transforms.seek(&position, Bias::Right);
6876        if self.diff_transforms.item().is_none()
6877            && self.diff_transforms.start().output_dimension == position
6878        {
6879            self.diff_transforms.prev();
6880        }
6881
6882        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6883        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6884            let overshoot = position - self.diff_transforms.start().output_dimension;
6885            excerpt_position += overshoot;
6886        }
6887
6888        self.excerpts.seek(&excerpt_position, Bias::Right);
6889        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6890            self.excerpts.prev();
6891        }
6892    }
6893
6894    fn seek_forward(&mut self, position: &MBD) {
6895        let position = OutputDimension(*position);
6896        self.cached_region.take();
6897        self.diff_transforms.seek_forward(&position, Bias::Right);
6898        if self.diff_transforms.item().is_none()
6899            && self.diff_transforms.start().output_dimension == position
6900        {
6901            self.diff_transforms.prev();
6902        }
6903
6904        let overshoot = position - self.diff_transforms.start().output_dimension;
6905        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6906        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6907            excerpt_position += overshoot;
6908        }
6909
6910        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6911        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6912            self.excerpts.prev();
6913        }
6914    }
6915
6916    fn next_excerpt(&mut self) {
6917        self.excerpts.next();
6918        self.seek_to_start_of_current_excerpt();
6919    }
6920
6921    fn prev_excerpt(&mut self) {
6922        self.excerpts.prev();
6923        self.seek_to_start_of_current_excerpt();
6924    }
6925
6926    fn seek_to_start_of_current_excerpt(&mut self) {
6927        self.cached_region.take();
6928
6929        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6930            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6931            && self.diff_transforms.next_item().is_some()
6932        {
6933            self.diff_transforms.next();
6934        }
6935    }
6936
6937    fn next_excerpt_forwards(&mut self) {
6938        self.excerpts.next();
6939        self.seek_to_start_of_current_excerpt_forward();
6940    }
6941
6942    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6943        self.cached_region.take();
6944
6945        if self
6946            .diff_transforms
6947            .seek_forward(self.excerpts.start(), Bias::Left)
6948            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6949            && self.diff_transforms.next_item().is_some()
6950        {
6951            self.diff_transforms.next();
6952        }
6953    }
6954
6955    fn next(&mut self) {
6956        self.cached_region.take();
6957        match self
6958            .diff_transforms
6959            .end()
6960            .excerpt_dimension
6961            .cmp(&self.excerpts.end())
6962        {
6963            cmp::Ordering::Less => self.diff_transforms.next(),
6964            cmp::Ordering::Greater => self.excerpts.next(),
6965            cmp::Ordering::Equal => {
6966                self.diff_transforms.next();
6967                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6968                    || self.diff_transforms.item().is_none()
6969                {
6970                    self.excerpts.next();
6971                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6972                    self.diff_transforms.item()
6973                    && self
6974                        .excerpts
6975                        .item()
6976                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6977                {
6978                    self.excerpts.next();
6979                }
6980            }
6981        }
6982    }
6983
6984    fn prev(&mut self) {
6985        self.cached_region.take();
6986        match self
6987            .diff_transforms
6988            .start()
6989            .excerpt_dimension
6990            .cmp(self.excerpts.start())
6991        {
6992            cmp::Ordering::Less => self.excerpts.prev(),
6993            cmp::Ordering::Greater => self.diff_transforms.prev(),
6994            cmp::Ordering::Equal => {
6995                self.diff_transforms.prev();
6996                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6997                    || self.diff_transforms.item().is_none()
6998                {
6999                    self.excerpts.prev();
7000                }
7001            }
7002        }
7003    }
7004
7005    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7006        self.cached_region
7007            .get_or_init(|| self.build_region())
7008            .as_ref()
7009    }
7010
7011    fn is_at_start_of_excerpt(&mut self) -> bool {
7012        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7013            return false;
7014        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7015            return true;
7016        }
7017
7018        self.diff_transforms.prev();
7019        let prev_transform = self.diff_transforms.item();
7020        self.diff_transforms.next();
7021
7022        prev_transform.is_none_or(|next_transform| {
7023            matches!(next_transform, DiffTransform::BufferContent { .. })
7024        })
7025    }
7026
7027    fn is_at_end_of_excerpt(&self) -> bool {
7028        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7029            return false;
7030        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7031            || self.diff_transforms.item().is_none()
7032        {
7033            return true;
7034        }
7035
7036        let next_transform = self.diff_transforms.next_item();
7037        next_transform.is_none_or(|next_transform| match next_transform {
7038            DiffTransform::BufferContent { .. } => true,
7039            DiffTransform::DeletedHunk { hunk_info, .. } => self
7040                .excerpts
7041                .item()
7042                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
7043        })
7044    }
7045
7046    fn main_buffer_position(&self) -> Option<BD> {
7047        let excerpt = self.excerpts.item()?;
7048        let buffer = excerpt.buffer_snapshot(self.snapshot);
7049        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7050        let mut buffer_start = buffer_context_start;
7051        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7052        buffer_start += overshoot;
7053        Some(buffer_start)
7054    }
7055
7056    fn buffer_position_at(&self, output_position: &MBD) -> Option<BD> {
7057        let excerpt = self.excerpts.item()?;
7058        let buffer = excerpt.buffer_snapshot(self.snapshot);
7059        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7060        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7061        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7062            excerpt_offset += *output_position - self.diff_transforms.start().output_dimension.0;
7063        }
7064        let mut result = buffer_context_start;
7065        result += excerpt_offset - *self.excerpts.start();
7066        Some(result)
7067    }
7068
7069    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7070        let excerpt = self.excerpts.item()?;
7071        match self.diff_transforms.item()? {
7072            DiffTransform::DeletedHunk {
7073                buffer_id,
7074                base_text_byte_range,
7075                has_trailing_newline,
7076                hunk_info,
7077                ..
7078            } => {
7079                let diff = find_diff_state(&self.snapshot.diffs, *buffer_id)?;
7080                let buffer = diff.base_text();
7081                let mut rope_cursor = buffer.as_rope().cursor(0);
7082                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7083                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7084                let mut buffer_end = buffer_start;
7085                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7086                let start = self.diff_transforms.start().output_dimension.0;
7087                let end = self.diff_transforms.end().output_dimension.0;
7088                Some(MultiBufferRegion {
7089                    buffer,
7090                    excerpt,
7091                    has_trailing_newline: *has_trailing_newline,
7092                    is_main_buffer: false,
7093                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7094                        hunk_info.hunk_secondary_status,
7095                    )),
7096                    buffer_range: buffer_start..buffer_end,
7097                    range: start..end,
7098                })
7099            }
7100            DiffTransform::BufferContent {
7101                inserted_hunk_info, ..
7102            } => {
7103                let buffer = excerpt.buffer_snapshot(self.snapshot);
7104                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7105
7106                let mut start = self.diff_transforms.start().output_dimension.0;
7107                let mut buffer_start = buffer_context_start;
7108                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7109                    let overshoot =
7110                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7111                    start += overshoot;
7112                } else {
7113                    let overshoot =
7114                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7115                    buffer_start += overshoot;
7116                }
7117
7118                let mut end;
7119                let mut buffer_end;
7120                let has_trailing_newline;
7121                let transform_end = self.diff_transforms.end();
7122                if transform_end.excerpt_dimension < self.excerpts.end() {
7123                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7124                    end = transform_end.output_dimension.0;
7125                    buffer_end = buffer_context_start;
7126                    buffer_end += overshoot;
7127                    has_trailing_newline = false;
7128                } else {
7129                    let overshoot =
7130                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7131                    end = self.diff_transforms.start().output_dimension.0;
7132                    end += overshoot;
7133                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7134                    has_trailing_newline = excerpt.has_trailing_newline;
7135                };
7136
7137                let diff_hunk_status = inserted_hunk_info.map(|info| {
7138                    if info.is_logically_deleted {
7139                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7140                    } else {
7141                        DiffHunkStatus::added(info.hunk_secondary_status)
7142                    }
7143                });
7144
7145                Some(MultiBufferRegion {
7146                    buffer,
7147                    excerpt,
7148                    has_trailing_newline,
7149                    is_main_buffer: true,
7150                    diff_hunk_status,
7151                    buffer_range: buffer_start..buffer_end,
7152                    range: start..end,
7153                })
7154            }
7155        }
7156    }
7157
7158    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7159        let excerpt = self.excerpts.item()?;
7160        match self.diff_transforms.item()? {
7161            &DiffTransform::DeletedHunk { .. } => {
7162                let start = self.diff_transforms.start().output_dimension.0;
7163                let end = self.diff_transforms.end().output_dimension.0;
7164                Some((excerpt, start..end))
7165            }
7166            DiffTransform::BufferContent { .. } => {
7167                let mut start = self.diff_transforms.start().output_dimension.0;
7168                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7169                    let overshoot =
7170                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7171                    start += overshoot;
7172                }
7173
7174                let mut end;
7175                let transform_end = self.diff_transforms.end();
7176                if transform_end.excerpt_dimension < self.excerpts.end() {
7177                    end = transform_end.output_dimension.0;
7178                } else {
7179                    let overshoot =
7180                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7181                    end = self.diff_transforms.start().output_dimension.0;
7182                    end += overshoot;
7183                };
7184
7185                Some((excerpt, start..end))
7186            }
7187        }
7188    }
7189
7190    fn excerpt(&self) -> Option<&'a Excerpt> {
7191        self.excerpts.item()
7192    }
7193}
7194
7195impl Excerpt {
7196    fn new(
7197        path_key: PathKey,
7198        path_key_index: PathKeyIndex,
7199        buffer_snapshot: &BufferSnapshot,
7200        range: ExcerptRange<text::Anchor>,
7201        has_trailing_newline: bool,
7202    ) -> Self {
7203        Excerpt {
7204            path_key,
7205            path_key_index,
7206            buffer_id: buffer_snapshot.remote_id(),
7207            max_buffer_row: range.context.end.to_point(&buffer_snapshot).row,
7208            text_summary: buffer_snapshot.text_summary_for_range::<TextSummary, _>(
7209                range.context.to_offset(&buffer_snapshot),
7210            ),
7211            range,
7212            has_trailing_newline,
7213        }
7214    }
7215
7216    fn buffer_snapshot<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
7217        &snapshot
7218            .buffers
7219            .get(&self.buffer_id)
7220            .expect("buffer snapshot not found for excerpt")
7221            .buffer_snapshot
7222    }
7223
7224    fn buffer(&self, multibuffer: &MultiBuffer) -> Entity<Buffer> {
7225        multibuffer
7226            .buffer(self.buffer_id)
7227            .expect("buffer entity not found for excerpt")
7228    }
7229
7230    fn chunks_in_range<'a>(
7231        &'a self,
7232        range: Range<usize>,
7233        language_aware: LanguageAwareStyling,
7234        snapshot: &'a MultiBufferSnapshot,
7235    ) -> ExcerptChunks<'a> {
7236        let buffer = self.buffer_snapshot(snapshot);
7237        let content_start = self.range.context.start.to_offset(buffer);
7238        let chunks_start = content_start + range.start;
7239        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7240
7241        let has_footer = self.has_trailing_newline
7242            && range.start <= self.text_summary.len
7243            && range.end > self.text_summary.len;
7244
7245        let content_chunks = buffer.chunks(chunks_start..chunks_end, language_aware);
7246
7247        ExcerptChunks {
7248            content_chunks,
7249            has_footer,
7250            end: self.end_anchor(),
7251        }
7252    }
7253
7254    fn seek_chunks(
7255        &self,
7256        excerpt_chunks: &mut ExcerptChunks,
7257        range: Range<usize>,
7258        snapshot: &MultiBufferSnapshot,
7259    ) {
7260        let buffer = self.buffer_snapshot(snapshot);
7261        let content_start = self.range.context.start.to_offset(buffer);
7262        let chunks_start = content_start + range.start;
7263        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7264        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7265        excerpt_chunks.has_footer = self.has_trailing_newline
7266            && range.start <= self.text_summary.len
7267            && range.end > self.text_summary.len;
7268    }
7269
7270    fn clip_anchor(
7271        &self,
7272        text_anchor: text::Anchor,
7273        snapshot: &MultiBufferSnapshot,
7274    ) -> text::Anchor {
7275        let buffer = self.buffer_snapshot(snapshot);
7276        if text_anchor.cmp(&self.range.context.start, buffer).is_lt() {
7277            self.range.context.start
7278        } else if text_anchor.cmp(&self.range.context.end, buffer).is_gt() {
7279            self.range.context.end
7280        } else {
7281            text_anchor
7282        }
7283    }
7284
7285    pub(crate) fn contains(&self, anchor: &ExcerptAnchor, snapshot: &MultiBufferSnapshot) -> bool {
7286        self.path_key_index == anchor.path
7287            && self.buffer_id == anchor.text_anchor.buffer_id
7288            && self
7289                .range
7290                .contains(&anchor.text_anchor(), self.buffer_snapshot(snapshot))
7291    }
7292
7293    fn start_anchor(&self) -> ExcerptAnchor {
7294        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.start)
7295    }
7296
7297    fn end_anchor(&self) -> ExcerptAnchor {
7298        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.end)
7299    }
7300}
7301
7302impl PartialEq for Excerpt {
7303    fn eq(&self, other: &Self) -> bool {
7304        self.path_key_index == other.path_key_index
7305            && self.buffer_id == other.buffer_id
7306            && self.range.context == other.range.context
7307    }
7308}
7309
7310impl sum_tree::Item for Excerpt {
7311    type Summary = ExcerptSummary;
7312
7313    fn summary(&self, _cx: ()) -> Self::Summary {
7314        let mut text = self.text_summary;
7315        if self.has_trailing_newline {
7316            text += TextSummary::from("\n");
7317        }
7318        ExcerptSummary {
7319            path_key: self.path_key.clone(),
7320            path_key_index: Some(self.path_key_index),
7321            max_anchor: Some(self.range.context.end),
7322            widest_line_number: self.max_buffer_row,
7323            text: text.into(),
7324            count: 1,
7325        }
7326    }
7327}
7328
7329impl DiffTransform {
7330    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7331        match self {
7332            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7333            DiffTransform::BufferContent {
7334                inserted_hunk_info, ..
7335            } => *inserted_hunk_info,
7336        }
7337    }
7338}
7339
7340impl sum_tree::Item for DiffTransform {
7341    type Summary = DiffTransformSummary;
7342
7343    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7344        match self {
7345            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7346                input: *summary,
7347                output: *summary,
7348            },
7349            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7350                input: MBTextSummary::default(),
7351                output: summary.into(),
7352            },
7353        }
7354    }
7355}
7356
7357impl DiffTransformSummary {
7358    fn excerpt_len(&self) -> ExcerptOffset {
7359        ExcerptDimension(self.input.len)
7360    }
7361}
7362
7363impl sum_tree::ContextLessSummary for DiffTransformSummary {
7364    fn zero() -> Self {
7365        DiffTransformSummary {
7366            input: MBTextSummary::default(),
7367            output: MBTextSummary::default(),
7368        }
7369    }
7370
7371    fn add_summary(&mut self, other: &Self) {
7372        self.input += other.input;
7373        self.output += other.output;
7374    }
7375}
7376
7377impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7378    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7379        PathKey::min()
7380    }
7381
7382    fn add_summary(
7383        &mut self,
7384        summary: &'_ ExcerptSummary,
7385        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7386    ) {
7387        *self = summary.path_key.clone();
7388    }
7389}
7390
7391impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7392    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7393        MultiBufferOffset::ZERO
7394    }
7395
7396    fn add_summary(
7397        &mut self,
7398        summary: &'_ ExcerptSummary,
7399        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7400    ) {
7401        *self += summary.text.len
7402    }
7403}
7404
7405impl sum_tree::ContextLessSummary for ExcerptSummary {
7406    fn zero() -> Self {
7407        Self::min()
7408    }
7409
7410    fn add_summary(&mut self, summary: &Self) {
7411        debug_assert!(
7412            summary.path_key >= self.path_key,
7413            "Path keys must be in ascending order: {:?} > {:?}",
7414            summary.path_key,
7415            self.path_key
7416        );
7417
7418        self.path_key = summary.path_key.clone();
7419        self.path_key_index = summary.path_key_index;
7420        self.max_anchor = summary.max_anchor;
7421        self.text += summary.text;
7422        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7423        self.count += summary.count;
7424    }
7425}
7426
7427impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget<'_> {
7428    fn cmp(
7429        &self,
7430        cursor_location: &ExcerptSummary,
7431        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7432    ) -> cmp::Ordering {
7433        match self {
7434            AnchorSeekTarget::Missing { path_key } => {
7435                // Want to end up after any excerpts for (a different buffer at) the original path
7436                match Ord::cmp(*path_key, &cursor_location.path_key) {
7437                    Ordering::Less => Ordering::Less,
7438                    Ordering::Equal | Ordering::Greater => Ordering::Greater,
7439                }
7440            }
7441            AnchorSeekTarget::Excerpt {
7442                path_key,
7443                path_key_index,
7444                anchor,
7445                snapshot,
7446            } => {
7447                if Some(*path_key_index) != cursor_location.path_key_index {
7448                    Ord::cmp(*path_key, &cursor_location.path_key)
7449                } else if let Some(max_anchor) = cursor_location.max_anchor {
7450                    debug_assert_eq!(max_anchor.buffer_id, snapshot.remote_id());
7451                    anchor.cmp(&max_anchor, snapshot)
7452                } else {
7453                    Ordering::Greater
7454                }
7455            }
7456            AnchorSeekTarget::Empty => Ordering::Greater,
7457        }
7458    }
7459}
7460
7461impl sum_tree::ContextLessSummary for PathKey {
7462    fn zero() -> Self {
7463        PathKey::min()
7464    }
7465
7466    fn add_summary(&mut self, summary: &Self) {
7467        debug_assert!(
7468            summary >= self,
7469            "Path keys must be in ascending order: {:?} > {:?}",
7470            summary,
7471            self
7472        );
7473
7474        *self = summary.clone();
7475    }
7476}
7477
7478impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7479    fn cmp(
7480        &self,
7481        cursor_location: &ExcerptSummary,
7482        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7483    ) -> cmp::Ordering {
7484        Ord::cmp(self, &cursor_location.path_key)
7485    }
7486}
7487
7488impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7489where
7490    MBD: MultiBufferDimension + Default,
7491{
7492    fn zero(_: ()) -> Self {
7493        ExcerptDimension(MBD::default())
7494    }
7495
7496    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7497        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7498    }
7499}
7500
7501#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7502struct OutputDimension<T>(T);
7503
7504impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7505    fn eq(&self, other: &T) -> bool {
7506        self.0 == *other
7507    }
7508}
7509
7510impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7511    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7512        self.0.partial_cmp(other)
7513    }
7514}
7515
7516impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7517where
7518    T: ops::Sub<U, Output = R>,
7519{
7520    type Output = R;
7521
7522    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7523        self.0 - other.0
7524    }
7525}
7526
7527impl<R, T, U> ops::Add<U> for OutputDimension<T>
7528where
7529    T: ops::Add<U, Output = R>,
7530{
7531    type Output = OutputDimension<R>;
7532
7533    fn add(self, other: U) -> Self::Output {
7534        OutputDimension(self.0 + other)
7535    }
7536}
7537
7538impl<T, U> AddAssign<U> for OutputDimension<T>
7539where
7540    T: AddAssign<U>,
7541{
7542    fn add_assign(&mut self, other: U) {
7543        self.0 += other;
7544    }
7545}
7546
7547impl<T, U> SubAssign<U> for OutputDimension<T>
7548where
7549    T: SubAssign<U>,
7550{
7551    fn sub_assign(&mut self, other: U) {
7552        self.0 -= other;
7553    }
7554}
7555
7556#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7557struct ExcerptDimension<T>(T);
7558
7559impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7560    fn eq(&self, other: &T) -> bool {
7561        self.0 == *other
7562    }
7563}
7564
7565impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7566    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7567        self.0.partial_cmp(other)
7568    }
7569}
7570
7571impl ExcerptOffset {
7572    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7573        self.0.saturating_sub(other.0)
7574    }
7575}
7576
7577impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7578where
7579    T: ops::Sub<U, Output = R>,
7580{
7581    type Output = R;
7582
7583    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7584        self.0 - other.0
7585    }
7586}
7587
7588impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7589where
7590    T: ops::Add<U, Output = R>,
7591{
7592    type Output = ExcerptDimension<R>;
7593
7594    fn add(self, other: U) -> Self::Output {
7595        ExcerptDimension(self.0 + other)
7596    }
7597}
7598
7599impl<T, U> AddAssign<U> for ExcerptDimension<T>
7600where
7601    T: AddAssign<U>,
7602{
7603    fn add_assign(&mut self, other: U) {
7604        self.0 += other;
7605    }
7606}
7607
7608impl<T, U> SubAssign<U> for ExcerptDimension<T>
7609where
7610    T: SubAssign<U>,
7611{
7612    fn sub_assign(&mut self, other: U) {
7613        self.0 -= other;
7614    }
7615}
7616
7617impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7618    fn zero(_: ()) -> Self {
7619        MultiBufferOffset::ZERO
7620    }
7621
7622    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7623        *self += summary.output.len;
7624    }
7625}
7626
7627impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7628    for ExcerptDimension<MBD>
7629where
7630    MBD: MultiBufferDimension + Ord,
7631{
7632    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7633        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7634    }
7635}
7636
7637impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7638    for ExcerptDimension<MBD>
7639where
7640    MBD: MultiBufferDimension + Ord,
7641{
7642    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7643        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7644    }
7645}
7646
7647impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7648    for ExcerptDimension<MBD>
7649{
7650    fn zero(_: ()) -> Self {
7651        ExcerptDimension(MBD::default())
7652    }
7653
7654    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7655        self.0.add_mb_text_summary(&summary.input)
7656    }
7657}
7658
7659impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7660    for OutputDimension<MBD>
7661where
7662    MBD: MultiBufferDimension + Ord,
7663{
7664    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7665        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7666    }
7667}
7668
7669impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7670    for OutputDimension<MBD>
7671{
7672    fn zero(_: ()) -> Self {
7673        OutputDimension(MBD::default())
7674    }
7675
7676    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7677        self.0.add_mb_text_summary(&summary.output)
7678    }
7679}
7680
7681impl MultiBufferRows<'_> {
7682    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7683        self.point = Point::new(row, 0);
7684        self.cursor.seek(&self.point);
7685    }
7686}
7687
7688impl Iterator for MultiBufferRows<'_> {
7689    type Item = RowInfo;
7690
7691    fn next(&mut self) -> Option<Self::Item> {
7692        if self.is_empty && self.point.row == 0 {
7693            self.point += Point::new(1, 0);
7694            return Some(RowInfo {
7695                buffer_id: None,
7696                buffer_row: Some(0),
7697                multibuffer_row: Some(MultiBufferRow(0)),
7698                diff_status: None,
7699                expand_info: None,
7700                wrapped_buffer_row: None,
7701            });
7702        }
7703
7704        let mut region = self.cursor.region()?.clone();
7705        while self.point >= region.range.end {
7706            self.cursor.next();
7707            if let Some(next_region) = self.cursor.region() {
7708                region = next_region.clone();
7709            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7710                let multibuffer_row = MultiBufferRow(self.point.row);
7711                let last_excerpt = self
7712                    .cursor
7713                    .excerpts
7714                    .item()
7715                    .or(self.cursor.excerpts.prev_item())?;
7716                let buffer_snapshot = last_excerpt.buffer_snapshot(self.cursor.snapshot);
7717                let last_row = last_excerpt.range.context.end.to_point(buffer_snapshot).row;
7718
7719                let first_row = last_excerpt
7720                    .range
7721                    .context
7722                    .start
7723                    .to_point(buffer_snapshot)
7724                    .row;
7725
7726                let expand_info = if self.is_singleton {
7727                    None
7728                } else {
7729                    let needs_expand_up = first_row == last_row
7730                        && last_row > 0
7731                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7732                    let needs_expand_down = last_row < buffer_snapshot.max_point().row;
7733
7734                    if needs_expand_up && needs_expand_down {
7735                        Some(ExpandExcerptDirection::UpAndDown)
7736                    } else if needs_expand_up {
7737                        Some(ExpandExcerptDirection::Up)
7738                    } else if needs_expand_down {
7739                        Some(ExpandExcerptDirection::Down)
7740                    } else {
7741                        None
7742                    }
7743                    .map(|direction| ExpandInfo {
7744                        direction,
7745                        start_anchor: Anchor::Excerpt(last_excerpt.start_anchor()),
7746                    })
7747                };
7748                self.point += Point::new(1, 0);
7749                return Some(RowInfo {
7750                    buffer_id: Some(last_excerpt.buffer_id),
7751                    buffer_row: Some(last_row),
7752                    multibuffer_row: Some(multibuffer_row),
7753                    diff_status: None,
7754                    wrapped_buffer_row: None,
7755                    expand_info,
7756                });
7757            } else {
7758                return None;
7759            };
7760        }
7761
7762        let overshoot = self.point - region.range.start;
7763        let buffer_point = region.buffer_range.start + overshoot;
7764        let expand_info = if self.is_singleton {
7765            None
7766        } else {
7767            let needs_expand_up = self.point.row == region.range.start.row
7768                && self.cursor.is_at_start_of_excerpt()
7769                && buffer_point.row > 0;
7770            let needs_expand_down = (region.excerpt.has_trailing_newline
7771                && self.point.row + 1 == region.range.end.row
7772                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7773                && self.cursor.is_at_end_of_excerpt()
7774                && buffer_point.row < region.buffer.max_point().row;
7775
7776            if needs_expand_up && needs_expand_down {
7777                Some(ExpandExcerptDirection::UpAndDown)
7778            } else if needs_expand_up {
7779                Some(ExpandExcerptDirection::Up)
7780            } else if needs_expand_down {
7781                Some(ExpandExcerptDirection::Down)
7782            } else {
7783                None
7784            }
7785            .map(|direction| ExpandInfo {
7786                direction,
7787                start_anchor: Anchor::Excerpt(region.excerpt.start_anchor()),
7788            })
7789        };
7790
7791        let result = Some(RowInfo {
7792            buffer_id: Some(region.buffer.remote_id()),
7793            buffer_row: Some(buffer_point.row),
7794            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7795            diff_status: region
7796                .diff_hunk_status
7797                .filter(|_| self.point < region.range.end),
7798            expand_info,
7799            wrapped_buffer_row: None,
7800        });
7801        self.point += Point::new(1, 0);
7802        result
7803    }
7804}
7805
7806impl<'a> MultiBufferChunks<'a> {
7807    pub fn offset(&self) -> MultiBufferOffset {
7808        self.range.start
7809    }
7810
7811    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7812        self.diff_transforms.seek(&range.end, Bias::Right);
7813        let mut excerpt_end = self.diff_transforms.start().1;
7814        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7815            let overshoot = range.end - self.diff_transforms.start().0;
7816            excerpt_end += overshoot;
7817        }
7818
7819        self.diff_transforms.seek(&range.start, Bias::Right);
7820        let mut excerpt_start = self.diff_transforms.start().1;
7821        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7822            let overshoot = range.start - self.diff_transforms.start().0;
7823            excerpt_start += overshoot;
7824        }
7825
7826        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7827        self.buffer_chunk.take();
7828        self.range = range;
7829    }
7830
7831    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7832        self.excerpt_offset_range = new_range.clone();
7833        self.excerpts.seek(&new_range.start, Bias::Right);
7834        if let Some(excerpt) = self.excerpts.item() {
7835            let excerpt_start = *self.excerpts.start();
7836            if let Some(excerpt_chunks) = self
7837                .excerpt_chunks
7838                .as_mut()
7839                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7840            {
7841                excerpt.seek_chunks(
7842                    excerpt_chunks,
7843                    (self.excerpt_offset_range.start - excerpt_start)
7844                        ..(self.excerpt_offset_range.end - excerpt_start),
7845                    self.snapshot,
7846                );
7847            } else {
7848                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7849                    (self.excerpt_offset_range.start - excerpt_start)
7850                        ..(self.excerpt_offset_range.end - excerpt_start),
7851                    self.language_aware,
7852                    self.snapshot,
7853                ));
7854            }
7855        } else {
7856            self.excerpt_chunks = None;
7857        }
7858    }
7859
7860    #[ztracing::instrument(skip_all)]
7861    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7862        loop {
7863            if self.excerpt_offset_range.is_empty() {
7864                return None;
7865            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7866                self.excerpt_offset_range.start += chunk.text.len();
7867                return Some(chunk);
7868            } else {
7869                self.excerpts.next();
7870                let excerpt = self.excerpts.item()?;
7871                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7872                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7873                    self.language_aware,
7874                    self.snapshot,
7875                ));
7876            }
7877        }
7878    }
7879}
7880
7881impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7882    type Item = &'a str;
7883
7884    fn next(&mut self) -> Option<Self::Item> {
7885        let mut region = self.cursor.region()?;
7886        if self.offset == region.range.start {
7887            self.cursor.prev();
7888            region = self.cursor.region()?;
7889            let start_overshoot = self.start.saturating_sub(region.range.start);
7890            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7891                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7892            ));
7893        }
7894
7895        if self.offset == region.range.end && region.has_trailing_newline {
7896            self.offset -= 1;
7897            Some("\n")
7898        } else {
7899            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7900            self.offset -= chunk.len();
7901            Some(chunk)
7902        }
7903    }
7904}
7905
7906impl<'a> Iterator for MultiBufferChunks<'a> {
7907    type Item = Chunk<'a>;
7908
7909    #[ztracing::instrument(skip_all)]
7910    fn next(&mut self) -> Option<Chunk<'a>> {
7911        if self.range.start >= self.range.end {
7912            return None;
7913        }
7914        if self.range.start == self.diff_transforms.end().0 {
7915            self.diff_transforms.next();
7916        }
7917
7918        let diff_transform_start = self.diff_transforms.start().0;
7919        let diff_transform_end = self.diff_transforms.end().0;
7920        debug_assert!(
7921            self.range.start < diff_transform_end,
7922            "{:?} < {:?} of ({1:?}..{2:?})",
7923            self.range.start,
7924            diff_transform_end,
7925            diff_transform_start
7926        );
7927
7928        let diff_transform = self.diff_transforms.item()?;
7929        match diff_transform {
7930            DiffTransform::BufferContent { .. } => {
7931                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7932                    chunk
7933                } else {
7934                    let chunk = self.next_excerpt_chunk().unwrap();
7935                    self.buffer_chunk.insert(chunk)
7936                };
7937
7938                let chunk_end = self.range.start + chunk.text.len();
7939                let diff_transform_end = diff_transform_end.min(self.range.end);
7940
7941                if diff_transform_end < chunk_end {
7942                    let split_idx = diff_transform_end - self.range.start;
7943                    let (before, after) = chunk.text.split_at(split_idx);
7944                    self.range.start = diff_transform_end;
7945                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7946                    let chars = chunk.chars & mask;
7947                    let tabs = chunk.tabs & mask;
7948                    let newlines = chunk.newlines & mask;
7949
7950                    chunk.text = after;
7951                    chunk.chars = chunk.chars >> split_idx;
7952                    chunk.tabs = chunk.tabs >> split_idx;
7953                    chunk.newlines = chunk.newlines >> split_idx;
7954
7955                    Some(Chunk {
7956                        text: before,
7957                        chars,
7958                        tabs,
7959                        newlines,
7960                        ..chunk.clone()
7961                    })
7962                } else {
7963                    self.range.start = chunk_end;
7964                    self.buffer_chunk.take()
7965                }
7966            }
7967            DiffTransform::DeletedHunk {
7968                buffer_id,
7969                base_text_byte_range,
7970                has_trailing_newline,
7971                ..
7972            } => {
7973                let base_text_start =
7974                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7975                let base_text_end =
7976                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7977                let base_text_end = base_text_end.min(base_text_byte_range.end);
7978
7979                let mut chunks = if let Some((_, mut chunks)) = self
7980                    .diff_base_chunks
7981                    .take()
7982                    .filter(|(id, _)| id == buffer_id)
7983                {
7984                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7985                    {
7986                        chunks.seek(base_text_start..base_text_end);
7987                    }
7988                    chunks
7989                } else {
7990                    let base_buffer =
7991                        &find_diff_state(&self.snapshot.diffs, *buffer_id)?.base_text();
7992                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7993                };
7994
7995                let chunk = if let Some(chunk) = chunks.next() {
7996                    self.range.start += chunk.text.len();
7997                    self.diff_base_chunks = Some((*buffer_id, chunks));
7998                    chunk
7999                } else {
8000                    debug_assert!(has_trailing_newline);
8001                    self.range.start += "\n".len();
8002                    Chunk {
8003                        text: "\n",
8004                        chars: 1u128,
8005                        newlines: 1u128,
8006                        ..Default::default()
8007                    }
8008                };
8009                Some(chunk)
8010            }
8011        }
8012    }
8013}
8014
8015impl MultiBufferBytes<'_> {
8016    fn consume(&mut self, len: usize) {
8017        self.range.start += len;
8018        self.chunk = &self.chunk[len..];
8019
8020        if !self.range.is_empty() && self.chunk.is_empty() {
8021            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8022                self.chunk = chunk;
8023            } else if self.has_trailing_newline {
8024                self.has_trailing_newline = false;
8025                self.chunk = b"\n";
8026            } else {
8027                self.cursor.next();
8028                if let Some(region) = self.cursor.region() {
8029                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8030                        region.buffer_range.start
8031                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8032                                .min(region.buffer_range.end),
8033                    );
8034                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8035                    self.excerpt_bytes = Some(excerpt_bytes);
8036                    self.has_trailing_newline =
8037                        region.has_trailing_newline && self.range.end >= region.range.end;
8038                    if self.chunk.is_empty() && self.has_trailing_newline {
8039                        self.has_trailing_newline = false;
8040                        self.chunk = b"\n";
8041                    }
8042                }
8043            }
8044        }
8045    }
8046}
8047
8048impl<'a> Iterator for MultiBufferBytes<'a> {
8049    type Item = &'a [u8];
8050
8051    fn next(&mut self) -> Option<Self::Item> {
8052        let chunk = self.chunk;
8053        if chunk.is_empty() {
8054            None
8055        } else {
8056            self.consume(chunk.len());
8057            Some(chunk)
8058        }
8059    }
8060}
8061
8062impl io::Read for MultiBufferBytes<'_> {
8063    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8064        let len = cmp::min(buf.len(), self.chunk.len());
8065        buf[..len].copy_from_slice(&self.chunk[..len]);
8066        if len > 0 {
8067            self.consume(len);
8068        }
8069        Ok(len)
8070    }
8071}
8072
8073impl io::Read for ReversedMultiBufferBytes<'_> {
8074    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8075        let len = cmp::min(buf.len(), self.chunk.len());
8076        buf[..len].copy_from_slice(&self.chunk[..len]);
8077        buf[..len].reverse();
8078        if len > 0 {
8079            self.range.end -= len;
8080            self.chunk = &self.chunk[..self.chunk.len() - len];
8081            if !self.range.is_empty()
8082                && self.chunk.is_empty()
8083                && let Some(chunk) = self.chunks.next()
8084            {
8085                self.chunk = chunk.as_bytes();
8086            }
8087        }
8088        Ok(len)
8089    }
8090}
8091
8092impl<'a> Iterator for ExcerptChunks<'a> {
8093    type Item = Chunk<'a>;
8094
8095    fn next(&mut self) -> Option<Self::Item> {
8096        if let Some(chunk) = self.content_chunks.next() {
8097            return Some(chunk);
8098        }
8099
8100        if self.has_footer {
8101            let text = "\n";
8102            let chars = 0b1;
8103            let newlines = 0b1;
8104            self.has_footer = false;
8105            return Some(Chunk {
8106                text,
8107                chars,
8108                newlines,
8109                ..Default::default()
8110            });
8111        }
8112
8113        None
8114    }
8115}
8116
8117impl ToOffset for Point {
8118    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8119        snapshot.point_to_offset(*self)
8120    }
8121    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8122        snapshot.point_to_offset_utf16(*self)
8123    }
8124}
8125
8126impl ToOffset for MultiBufferOffset {
8127    #[track_caller]
8128    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8129        assert!(
8130            *self <= snapshot.len(),
8131            "offset {} is greater than the snapshot.len() {}",
8132            self.0,
8133            snapshot.len().0,
8134        );
8135        *self
8136    }
8137    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8138        snapshot.offset_to_offset_utf16(*self)
8139    }
8140}
8141
8142impl ToOffset for MultiBufferOffsetUtf16 {
8143    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8144        snapshot.offset_utf16_to_offset(*self)
8145    }
8146
8147    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8148        *self
8149    }
8150}
8151
8152impl ToOffset for PointUtf16 {
8153    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8154        snapshot.point_utf16_to_offset(*self)
8155    }
8156    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8157        snapshot.point_utf16_to_offset_utf16(*self)
8158    }
8159}
8160
8161impl ToPoint for MultiBufferOffset {
8162    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8163        snapshot.offset_to_point(*self)
8164    }
8165    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8166        snapshot.offset_to_point_utf16(*self)
8167    }
8168}
8169
8170impl ToPoint for Point {
8171    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8172        *self
8173    }
8174    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8175        snapshot.point_to_point_utf16(*self)
8176    }
8177}
8178
8179impl ToPoint for PointUtf16 {
8180    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8181        snapshot.point_utf16_to_point(*self)
8182    }
8183    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8184        *self
8185    }
8186}
8187
8188#[cfg(debug_assertions)]
8189pub mod debug {
8190    use super::*;
8191
8192    pub trait ToMultiBufferDebugRanges {
8193        fn to_multi_buffer_debug_ranges(
8194            &self,
8195            snapshot: &MultiBufferSnapshot,
8196        ) -> Vec<Range<MultiBufferOffset>>;
8197    }
8198
8199    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8200        fn to_multi_buffer_debug_ranges(
8201            &self,
8202            snapshot: &MultiBufferSnapshot,
8203        ) -> Vec<Range<MultiBufferOffset>> {
8204            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8205        }
8206    }
8207
8208    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8209        fn to_multi_buffer_debug_ranges(
8210            &self,
8211            snapshot: &MultiBufferSnapshot,
8212        ) -> Vec<Range<MultiBufferOffset>> {
8213            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8214                .to_multi_buffer_debug_ranges(snapshot)
8215        }
8216    }
8217
8218    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8219        fn to_multi_buffer_debug_ranges(
8220            &self,
8221            snapshot: &MultiBufferSnapshot,
8222        ) -> Vec<Range<MultiBufferOffset>> {
8223            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8224        }
8225    }
8226
8227    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8228        fn to_multi_buffer_debug_ranges(
8229            &self,
8230            snapshot: &MultiBufferSnapshot,
8231        ) -> Vec<Range<MultiBufferOffset>> {
8232            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8233        }
8234    }
8235
8236    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8237        fn to_multi_buffer_debug_ranges(
8238            &self,
8239            snapshot: &MultiBufferSnapshot,
8240        ) -> Vec<Range<MultiBufferOffset>> {
8241            self.iter()
8242                .map(|item| {
8243                    let offset = item.to_offset(snapshot);
8244                    offset..offset
8245                })
8246                .collect()
8247        }
8248    }
8249
8250    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8251        fn to_multi_buffer_debug_ranges(
8252            &self,
8253            snapshot: &MultiBufferSnapshot,
8254        ) -> Vec<Range<MultiBufferOffset>> {
8255            self.iter()
8256                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8257                .collect()
8258        }
8259    }
8260}