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