multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        /// Contains only buffer IDs for which all excerpts have been removed.
 109        /// Buffers that still have remaining excerpts are never included.
 110        removed_buffer_ids: Vec<BufferId>,
 111    },
 112    ExcerptsExpanded {
 113        ids: Vec<ExcerptId>,
 114    },
 115    ExcerptsEdited {
 116        excerpt_ids: Vec<ExcerptId>,
 117        buffer_ids: Vec<BufferId>,
 118    },
 119    DiffHunksToggled,
 120    Edited {
 121        edited_buffer: Option<Entity<Buffer>>,
 122        is_local: bool,
 123    },
 124    TransactionUndone {
 125        transaction_id: TransactionId,
 126    },
 127    Reloaded,
 128    LanguageChanged(BufferId, bool),
 129    Reparsed(BufferId),
 130    Saved,
 131    FileHandleChanged,
 132    DirtyChanged,
 133    DiagnosticsUpdated,
 134    BufferDiffChanged,
 135}
 136
 137/// A diff hunk, representing a range of consequent lines in a multibuffer.
 138#[derive(Debug, Clone, PartialEq, Eq)]
 139pub struct MultiBufferDiffHunk {
 140    /// The row range in the multibuffer where this diff hunk appears.
 141    pub row_range: Range<MultiBufferRow>,
 142    /// The buffer ID that this hunk belongs to.
 143    pub buffer_id: BufferId,
 144    /// The range of the underlying buffer that this hunk corresponds to.
 145    pub buffer_range: Range<text::Anchor>,
 146    /// The excerpt that contains the diff hunk.
 147    pub excerpt_id: ExcerptId,
 148    /// The range within the buffer's diff base that this hunk corresponds to.
 149    pub diff_base_byte_range: Range<BufferOffset>,
 150    /// The status of this hunk (added/modified/deleted and secondary status).
 151    pub status: DiffHunkStatus,
 152    /// The word diffs for this hunk.
 153    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 154}
 155
 156impl MultiBufferDiffHunk {
 157    pub fn status(&self) -> DiffHunkStatus {
 158        self.status
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 163            && self.buffer_range.start.is_min()
 164            && self.buffer_range.end.is_max()
 165    }
 166
 167    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 168        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 169        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 170        start..end
 171    }
 172}
 173
 174pub type MultiBufferPoint = Point;
 175type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 176type ExcerptPoint = ExcerptDimension<Point>;
 177
 178#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 179#[serde(transparent)]
 180pub struct MultiBufferRow(pub u32);
 181
 182impl MultiBufferRow {
 183    pub const MIN: Self = Self(0);
 184    pub const MAX: Self = Self(u32::MAX);
 185}
 186
 187impl ops::Add<usize> for MultiBufferRow {
 188    type Output = Self;
 189
 190    fn add(self, rhs: usize) -> Self::Output {
 191        MultiBufferRow(self.0 + rhs as u32)
 192    }
 193}
 194
 195pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 196    type TextDimension: TextDimension;
 197    fn from_summary(summary: &MBTextSummary) -> Self;
 198
 199    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 200
 201    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 202}
 203
 204// todo(lw): MultiBufferPoint
 205impl MultiBufferDimension for Point {
 206    type TextDimension = Point;
 207    fn from_summary(summary: &MBTextSummary) -> Self {
 208        summary.lines
 209    }
 210
 211    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 212        *self += *other;
 213    }
 214
 215    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 216        *self += summary.lines;
 217    }
 218}
 219
 220// todo(lw): MultiBufferPointUtf16
 221impl MultiBufferDimension for PointUtf16 {
 222    type TextDimension = PointUtf16;
 223    fn from_summary(summary: &MBTextSummary) -> Self {
 224        summary.lines_utf16()
 225    }
 226
 227    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 228        *self += *other;
 229    }
 230
 231    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 232        *self += summary.lines_utf16();
 233    }
 234}
 235
 236#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 237pub struct MultiBufferOffset(pub usize);
 238
 239impl fmt::Display for MultiBufferOffset {
 240    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 241        write!(f, "{}", self.0)
 242    }
 243}
 244
 245impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 246    type Sampler = MultiBufferOffsetUniformSampler;
 247}
 248
 249pub struct MultiBufferOffsetUniformSampler {
 250    sampler: rand::distr::uniform::UniformUsize,
 251}
 252
 253impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 254    type X = MultiBufferOffset;
 255
 256    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 257    where
 258        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 260    {
 261        let low = *low_b.borrow();
 262        let high = *high_b.borrow();
 263        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 264        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 265    }
 266
 267    #[inline] // if the range is constant, this helps LLVM to do the
 268    // calculations at compile-time.
 269    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 270    where
 271        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 273    {
 274        let low = *low_b.borrow();
 275        let high = *high_b.borrow();
 276        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 277        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 278    }
 279
 280    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 281        MultiBufferOffset(self.sampler.sample(rng))
 282    }
 283}
 284impl MultiBufferDimension for MultiBufferOffset {
 285    type TextDimension = usize;
 286    fn from_summary(summary: &MBTextSummary) -> Self {
 287        summary.len
 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 += summary.len;
 296    }
 297}
 298impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 299    type TextDimension = OffsetUtf16;
 300    fn from_summary(summary: &MBTextSummary) -> Self {
 301        MultiBufferOffsetUtf16(summary.len_utf16)
 302    }
 303
 304    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 305        self.0 += *other;
 306    }
 307
 308    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 309        self.0 += summary.len_utf16;
 310    }
 311}
 312
 313#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 314pub struct BufferOffset(pub usize);
 315
 316impl TextDimension for BufferOffset {
 317    fn from_text_summary(summary: &TextSummary) -> Self {
 318        BufferOffset(usize::from_text_summary(summary))
 319    }
 320    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 321        BufferOffset(usize::from_chunk(chunk))
 322    }
 323    fn add_assign(&mut self, other: &Self) {
 324        TextDimension::add_assign(&mut self.0, &other.0);
 325    }
 326}
 327impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 328    fn zero(cx: ()) -> Self {
 329        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 330    }
 331
 332    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 333        usize::add_summary(&mut self.0, summary, cx);
 334    }
 335}
 336
 337impl Sub for BufferOffset {
 338    type Output = usize;
 339
 340    fn sub(self, other: BufferOffset) -> Self::Output {
 341        self.0 - other.0
 342    }
 343}
 344
 345impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 346    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 347        self.0 += other.key;
 348    }
 349}
 350
 351impl language::ToPoint for BufferOffset {
 352    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 353        self.0.to_point(snapshot)
 354    }
 355}
 356
 357impl language::ToPointUtf16 for BufferOffset {
 358    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 359        self.0.to_point_utf16(snapshot)
 360    }
 361}
 362
 363impl language::ToOffset for BufferOffset {
 364    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 365        self.0.to_offset(snapshot)
 366    }
 367}
 368
 369impl language::ToOffsetUtf16 for BufferOffset {
 370    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 371        self.0.to_offset_utf16(snapshot)
 372    }
 373}
 374
 375#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 376pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 377
 378impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 379    type Output = MultiBufferOffsetUtf16;
 380
 381    fn add(self, rhs: usize) -> Self::Output {
 382        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 383    }
 384}
 385
 386impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 387    type Output = Self;
 388
 389    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 390        MultiBufferOffsetUtf16(self.0 + rhs)
 391    }
 392}
 393
 394impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 395    fn add_assign(&mut self, rhs: OffsetUtf16) {
 396        self.0 += rhs;
 397    }
 398}
 399
 400impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 401    fn add_assign(&mut self, rhs: usize) {
 402        self.0.0 += rhs;
 403    }
 404}
 405
 406impl Sub for MultiBufferOffsetUtf16 {
 407    type Output = OffsetUtf16;
 408
 409    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 410        self.0 - other.0
 411    }
 412}
 413
 414impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 415    type Output = MultiBufferOffsetUtf16;
 416
 417    fn sub(self, other: OffsetUtf16) -> Self::Output {
 418        MultiBufferOffsetUtf16(self.0 - other)
 419    }
 420}
 421
 422#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 423pub struct BufferOffsetUtf16(pub OffsetUtf16);
 424
 425impl MultiBufferOffset {
 426    const ZERO: Self = Self(0);
 427    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 428        self.0.saturating_sub(other.0)
 429    }
 430    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 431        MultiBufferOffset(self.0.saturating_sub(other))
 432    }
 433}
 434
 435impl ops::Sub for MultiBufferOffset {
 436    type Output = usize;
 437
 438    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 439        self.0 - other.0
 440    }
 441}
 442
 443impl ops::Sub<usize> for MultiBufferOffset {
 444    type Output = Self;
 445
 446    fn sub(self, other: usize) -> Self::Output {
 447        MultiBufferOffset(self.0 - other)
 448    }
 449}
 450
 451impl ops::SubAssign<usize> for MultiBufferOffset {
 452    fn sub_assign(&mut self, other: usize) {
 453        self.0 -= other;
 454    }
 455}
 456
 457impl ops::Add<usize> for BufferOffset {
 458    type Output = Self;
 459
 460    fn add(self, rhs: usize) -> Self::Output {
 461        BufferOffset(self.0 + rhs)
 462    }
 463}
 464
 465impl ops::AddAssign<usize> for BufferOffset {
 466    fn add_assign(&mut self, other: usize) {
 467        self.0 += other;
 468    }
 469}
 470
 471impl ops::Add<usize> for MultiBufferOffset {
 472    type Output = Self;
 473
 474    fn add(self, rhs: usize) -> Self::Output {
 475        MultiBufferOffset(self.0 + rhs)
 476    }
 477}
 478
 479impl ops::AddAssign<usize> for MultiBufferOffset {
 480    fn add_assign(&mut self, other: usize) {
 481        self.0 += other;
 482    }
 483}
 484
 485impl ops::Add<isize> for MultiBufferOffset {
 486    type Output = Self;
 487
 488    fn add(self, rhs: isize) -> Self::Output {
 489        MultiBufferOffset((self.0 as isize + rhs) as usize)
 490    }
 491}
 492
 493impl ops::Add for MultiBufferOffset {
 494    type Output = Self;
 495
 496    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 497        MultiBufferOffset(self.0 + rhs.0)
 498    }
 499}
 500
 501impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 502    fn add_assign(&mut self, other: MultiBufferOffset) {
 503        self.0 += other.0;
 504    }
 505}
 506
 507pub trait ToOffset: 'static + fmt::Debug {
 508    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 509    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 510}
 511
 512pub trait ToPoint: 'static + fmt::Debug {
 513    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 514    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 515}
 516
 517struct BufferState {
 518    buffer: Entity<Buffer>,
 519    last_version: RefCell<clock::Global>,
 520    last_non_text_state_update_count: Cell<usize>,
 521    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 522    excerpts: Vec<Locator>,
 523    _subscriptions: [gpui::Subscription; 2],
 524}
 525
 526struct DiffState {
 527    diff: Entity<BufferDiff>,
 528    main_buffer: Option<Entity<language::Buffer>>,
 529    _subscription: gpui::Subscription,
 530}
 531
 532impl DiffState {
 533    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 534        DiffStateSnapshot {
 535            diff: self.diff.read(cx).snapshot(cx),
 536            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 537        }
 538    }
 539}
 540
 541#[derive(Clone)]
 542struct DiffStateSnapshot {
 543    diff: BufferDiffSnapshot,
 544    main_buffer: Option<language::BufferSnapshot>,
 545}
 546
 547impl std::ops::Deref for DiffStateSnapshot {
 548    type Target = BufferDiffSnapshot;
 549
 550    fn deref(&self) -> &Self::Target {
 551        &self.diff
 552    }
 553}
 554
 555impl DiffState {
 556    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 557        DiffState {
 558            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 559                BufferDiffEvent::DiffChanged(DiffChanged {
 560                    changed_range,
 561                    base_text_changed_range: _,
 562                    extended_range,
 563                }) => {
 564                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 565                    let range = if use_extended {
 566                        extended_range.clone()
 567                    } else {
 568                        changed_range.clone()
 569                    };
 570                    if let Some(range) = range {
 571                        this.buffer_diff_changed(diff, range, cx)
 572                    }
 573                    cx.emit(Event::BufferDiffChanged);
 574                }
 575                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 576                _ => {}
 577            }),
 578            diff,
 579            main_buffer: None,
 580        }
 581    }
 582
 583    fn new_inverted(
 584        diff: Entity<BufferDiff>,
 585        main_buffer: Entity<language::Buffer>,
 586        cx: &mut Context<MultiBuffer>,
 587    ) -> Self {
 588        let weak_main_buffer = main_buffer.downgrade();
 589        DiffState {
 590            _subscription: cx.subscribe(&diff, {
 591                move |this, diff, event, cx| {
 592                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 593                        return;
 594                    };
 595                    match event {
 596                        BufferDiffEvent::DiffChanged(DiffChanged {
 597                            changed_range: _,
 598                            base_text_changed_range,
 599                            extended_range: _,
 600                        }) => {
 601                            this.inverted_buffer_diff_changed(
 602                                diff,
 603                                main_buffer,
 604                                base_text_changed_range.clone(),
 605                                cx,
 606                            );
 607                            cx.emit(Event::BufferDiffChanged);
 608                        }
 609                        BufferDiffEvent::LanguageChanged => {
 610                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 611                        }
 612                        _ => {}
 613                    }
 614                }
 615            }),
 616            diff,
 617            main_buffer: Some(main_buffer),
 618        }
 619    }
 620}
 621
 622/// The contents of a [`MultiBuffer`] at a single point in time.
 623#[derive(Clone, Default)]
 624pub struct MultiBufferSnapshot {
 625    excerpts: SumTree<Excerpt>,
 626    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 627    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 628    diff_transforms: SumTree<DiffTransform>,
 629    excerpt_ids: SumTree<ExcerptIdMapping>,
 630    replaced_excerpts: Arc<HashMap<ExcerptId, ExcerptId>>,
 631    non_text_state_update_count: usize,
 632    edit_count: usize,
 633    is_dirty: bool,
 634    has_deleted_file: bool,
 635    has_conflict: bool,
 636    has_inverted_diff: bool,
 637    singleton: bool,
 638    trailing_excerpt_update_count: usize,
 639    all_diff_hunks_expanded: bool,
 640    show_deleted_hunks: bool,
 641    use_extended_diff_range: bool,
 642    show_headers: bool,
 643}
 644
 645// follower: None
 646// - BufferContent(Some)
 647// - BufferContent(None)
 648// - DeletedHunk
 649//
 650// follower: Some
 651// - BufferContent(Some)
 652// - BufferContent(None)
 653
 654#[derive(Debug, Clone)]
 655enum DiffTransform {
 656    // RealText
 657    BufferContent {
 658        summary: MBTextSummary,
 659        // modified_hunk_info
 660        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 661    },
 662    // ExpandedHunkText
 663    DeletedHunk {
 664        summary: TextSummary,
 665        buffer_id: BufferId,
 666        hunk_info: DiffTransformHunkInfo,
 667        base_text_byte_range: Range<usize>,
 668        has_trailing_newline: bool,
 669    },
 670}
 671
 672#[derive(Clone, Copy, Debug)]
 673struct DiffTransformHunkInfo {
 674    excerpt_id: ExcerptId,
 675    hunk_start_anchor: text::Anchor,
 676    hunk_secondary_status: DiffHunkSecondaryStatus,
 677    is_logically_deleted: bool,
 678}
 679
 680impl Eq for DiffTransformHunkInfo {}
 681
 682impl PartialEq for DiffTransformHunkInfo {
 683    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 684        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 685    }
 686}
 687
 688impl std::hash::Hash for DiffTransformHunkInfo {
 689    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 690        self.excerpt_id.hash(state);
 691        self.hunk_start_anchor.hash(state);
 692    }
 693}
 694
 695#[derive(Clone)]
 696pub struct ExcerptInfo {
 697    pub id: ExcerptId,
 698    pub buffer: Arc<BufferSnapshot>,
 699    pub buffer_id: BufferId,
 700    pub range: ExcerptRange<text::Anchor>,
 701    pub end_row: MultiBufferRow,
 702}
 703
 704impl std::fmt::Debug for ExcerptInfo {
 705    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 706        f.debug_struct(type_name::<Self>())
 707            .field("id", &self.id)
 708            .field("buffer_id", &self.buffer_id)
 709            .field("path", &self.buffer.file().map(|f| f.path()))
 710            .field("range", &self.range)
 711            .finish()
 712    }
 713}
 714
 715/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 716#[derive(Debug)]
 717pub struct ExcerptBoundary {
 718    pub prev: Option<ExcerptInfo>,
 719    pub next: ExcerptInfo,
 720    /// The row in the `MultiBuffer` where the boundary is located
 721    pub row: MultiBufferRow,
 722}
 723
 724impl ExcerptBoundary {
 725    pub fn starts_new_buffer(&self) -> bool {
 726        match (self.prev.as_ref(), &self.next) {
 727            (None, _) => true,
 728            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 729        }
 730    }
 731}
 732
 733#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 734pub struct ExpandInfo {
 735    pub direction: ExpandExcerptDirection,
 736    pub excerpt_id: ExcerptId,
 737}
 738
 739#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 740pub struct RowInfo {
 741    pub buffer_id: Option<BufferId>,
 742    pub buffer_row: Option<u32>,
 743    pub multibuffer_row: Option<MultiBufferRow>,
 744    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 745    pub expand_info: Option<ExpandInfo>,
 746    pub wrapped_buffer_row: Option<u32>,
 747}
 748
 749/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 750#[derive(Clone)]
 751struct Excerpt {
 752    /// The unique identifier for this excerpt
 753    id: ExcerptId,
 754    /// The location of the excerpt in the [`MultiBuffer`]
 755    locator: Locator,
 756    /// The buffer being excerpted
 757    buffer_id: BufferId,
 758    /// A snapshot of the buffer being excerpted
 759    buffer: Arc<BufferSnapshot>,
 760    /// The range of the buffer to be shown in the excerpt
 761    range: ExcerptRange<text::Anchor>,
 762    /// The last row in the excerpted slice of the buffer
 763    max_buffer_row: BufferRow,
 764    /// A summary of the text in the excerpt
 765    text_summary: TextSummary,
 766    has_trailing_newline: bool,
 767}
 768
 769/// A public view into an `Excerpt` in a [`MultiBuffer`].
 770///
 771/// Contains methods for getting the [`Buffer`] of the excerpt,
 772/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 773#[derive(Clone)]
 774pub struct MultiBufferExcerpt<'a> {
 775    excerpt: &'a Excerpt,
 776    diff_transforms:
 777        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 778    /// The offset in the multibuffer considering diff transforms.
 779    offset: MultiBufferOffset,
 780    /// The offset in the multibuffer without diff transforms.
 781    excerpt_offset: ExcerptOffset,
 782    buffer_offset: BufferOffset,
 783}
 784
 785#[derive(Clone, Debug)]
 786struct ExcerptIdMapping {
 787    id: ExcerptId,
 788    locator: Locator,
 789}
 790
 791/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 792/// These ranges are relative to the buffer itself
 793#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 794pub struct ExcerptRange<T> {
 795    /// The full range of text to be shown in the excerpt.
 796    pub context: Range<T>,
 797    /// The primary range of text to be highlighted in the excerpt.
 798    /// In a multi-buffer search, this would be the text that matched the search
 799    pub primary: Range<T>,
 800}
 801
 802impl<T: Clone> ExcerptRange<T> {
 803    pub fn new(context: Range<T>) -> Self {
 804        Self {
 805            context: context.clone(),
 806            primary: context,
 807        }
 808    }
 809}
 810
 811#[derive(Clone, Debug, Default)]
 812pub struct ExcerptSummary {
 813    excerpt_id: ExcerptId,
 814    /// The location of the last [`Excerpt`] being summarized
 815    excerpt_locator: Locator,
 816    widest_line_number: u32,
 817    text: MBTextSummary,
 818    count: usize,
 819}
 820
 821#[derive(Debug, Clone)]
 822pub struct DiffTransformSummary {
 823    input: MBTextSummary,
 824    output: MBTextSummary,
 825}
 826
 827/// Summary of a string of text.
 828#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 829pub struct MBTextSummary {
 830    /// Length in bytes.
 831    pub len: MultiBufferOffset,
 832    /// Length in UTF-8.
 833    pub chars: usize,
 834    /// Length in UTF-16 code units
 835    pub len_utf16: OffsetUtf16,
 836    /// A point representing the number of lines and the length of the last line.
 837    ///
 838    /// In other words, it marks the point after the last byte in the text, (if
 839    /// EOF was a character, this would be its position).
 840    pub lines: Point,
 841    /// How many `char`s are in the first line
 842    pub first_line_chars: u32,
 843    /// How many `char`s are in the last line
 844    pub last_line_chars: u32,
 845    /// How many UTF-16 code units are in the last line
 846    pub last_line_len_utf16: u32,
 847    /// The row idx of the longest row
 848    pub longest_row: u32,
 849    /// How many `char`s are in the longest row
 850    pub longest_row_chars: u32,
 851}
 852
 853impl From<TextSummary> for MBTextSummary {
 854    fn from(summary: TextSummary) -> Self {
 855        MBTextSummary {
 856            len: MultiBufferOffset(summary.len),
 857            chars: summary.chars,
 858            len_utf16: summary.len_utf16,
 859            lines: summary.lines,
 860            first_line_chars: summary.first_line_chars,
 861            last_line_chars: summary.last_line_chars,
 862            last_line_len_utf16: summary.last_line_len_utf16,
 863            longest_row: summary.longest_row,
 864            longest_row_chars: summary.longest_row_chars,
 865        }
 866    }
 867}
 868
 869impl From<MBTextSummary> for TextSummary {
 870    fn from(summary: MBTextSummary) -> Self {
 871        TextSummary {
 872            len: summary.len.0,
 873            chars: summary.chars,
 874            len_utf16: summary.len_utf16,
 875            lines: summary.lines,
 876            first_line_chars: summary.first_line_chars,
 877            last_line_chars: summary.last_line_chars,
 878            last_line_len_utf16: summary.last_line_len_utf16,
 879            longest_row: summary.longest_row,
 880            longest_row_chars: summary.longest_row_chars,
 881        }
 882    }
 883}
 884
 885impl From<&str> for MBTextSummary {
 886    fn from(text: &str) -> Self {
 887        MBTextSummary::from(TextSummary::from(text))
 888    }
 889}
 890
 891impl MultiBufferDimension for MBTextSummary {
 892    type TextDimension = TextSummary;
 893
 894    fn from_summary(summary: &MBTextSummary) -> Self {
 895        *summary
 896    }
 897
 898    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 899        *self += *summary;
 900    }
 901
 902    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 903        *self += *summary;
 904    }
 905}
 906
 907impl AddAssign for MBTextSummary {
 908    fn add_assign(&mut self, other: MBTextSummary) {
 909        let joined_chars = self.last_line_chars + other.first_line_chars;
 910        if joined_chars > self.longest_row_chars {
 911            self.longest_row = self.lines.row;
 912            self.longest_row_chars = joined_chars;
 913        }
 914        if other.longest_row_chars > self.longest_row_chars {
 915            self.longest_row = self.lines.row + other.longest_row;
 916            self.longest_row_chars = other.longest_row_chars;
 917        }
 918
 919        if self.lines.row == 0 {
 920            self.first_line_chars += other.first_line_chars;
 921        }
 922
 923        if other.lines.row == 0 {
 924            self.last_line_chars += other.first_line_chars;
 925            self.last_line_len_utf16 += other.last_line_len_utf16;
 926        } else {
 927            self.last_line_chars = other.last_line_chars;
 928            self.last_line_len_utf16 = other.last_line_len_utf16;
 929        }
 930
 931        self.chars += other.chars;
 932        self.len += other.len;
 933        self.len_utf16 += other.len_utf16;
 934        self.lines += other.lines;
 935    }
 936}
 937
 938impl AddAssign<TextSummary> for MBTextSummary {
 939    fn add_assign(&mut self, other: TextSummary) {
 940        *self += MBTextSummary::from(other);
 941    }
 942}
 943
 944impl MBTextSummary {
 945    pub fn lines_utf16(&self) -> PointUtf16 {
 946        PointUtf16 {
 947            row: self.lines.row,
 948            column: self.last_line_len_utf16,
 949        }
 950    }
 951}
 952
 953impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 954where
 955    K: MultiBufferDimension,
 956    V: MultiBufferDimension,
 957{
 958    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 959
 960    fn from_summary(summary: &MBTextSummary) -> Self {
 961        Self {
 962            key: K::from_summary(summary),
 963            value: Some(V::from_summary(summary)),
 964        }
 965    }
 966
 967    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 968        self.key.add_text_dim(&summary.key);
 969        if let Some(value) = &mut self.value {
 970            if let Some(other_value) = summary.value.as_ref() {
 971                value.add_text_dim(other_value);
 972            }
 973        }
 974    }
 975
 976    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 977        self.key.add_mb_text_summary(summary);
 978        if let Some(value) = &mut self.value {
 979            value.add_mb_text_summary(summary);
 980        }
 981    }
 982}
 983
 984#[derive(Clone)]
 985pub struct MultiBufferRows<'a> {
 986    point: Point,
 987    is_empty: bool,
 988    is_singleton: bool,
 989    cursor: MultiBufferCursor<'a, Point, Point>,
 990}
 991
 992pub struct MultiBufferChunks<'a> {
 993    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 994    diff_transforms:
 995        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 996    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 997    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 998    buffer_chunk: Option<Chunk<'a>>,
 999    range: Range<MultiBufferOffset>,
1000    excerpt_offset_range: Range<ExcerptOffset>,
1001    excerpt_chunks: Option<ExcerptChunks<'a>>,
1002    language_aware: bool,
1003}
1004
1005pub struct ReversedMultiBufferChunks<'a> {
1006    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1007    current_chunks: Option<rope::Chunks<'a>>,
1008    start: MultiBufferOffset,
1009    offset: MultiBufferOffset,
1010}
1011
1012pub struct MultiBufferBytes<'a> {
1013    range: Range<MultiBufferOffset>,
1014    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1015    excerpt_bytes: Option<text::Bytes<'a>>,
1016    has_trailing_newline: bool,
1017    chunk: &'a [u8],
1018}
1019
1020pub struct ReversedMultiBufferBytes<'a> {
1021    range: Range<MultiBufferOffset>,
1022    chunks: ReversedMultiBufferChunks<'a>,
1023    chunk: &'a [u8],
1024}
1025
1026#[derive(Clone)]
1027struct DiffTransforms<MBD> {
1028    output_dimension: OutputDimension<MBD>,
1029    excerpt_dimension: ExcerptDimension<MBD>,
1030}
1031
1032impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1033    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1034        Self {
1035            output_dimension: OutputDimension::zero(cx),
1036            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1037                cx,
1038            ),
1039        }
1040    }
1041
1042    fn add_summary(
1043        &mut self,
1044        summary: &'a DiffTransformSummary,
1045        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1046    ) {
1047        self.output_dimension.add_summary(summary, cx);
1048        self.excerpt_dimension.add_summary(summary, cx);
1049    }
1050}
1051
1052#[derive(Clone)]
1053struct MultiBufferCursor<'a, MBD, BD> {
1054    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1055    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1056    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1057    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1058}
1059
1060#[derive(Clone)]
1061struct MultiBufferRegion<'a, MBD, BD> {
1062    buffer: &'a BufferSnapshot,
1063    is_main_buffer: bool,
1064    diff_hunk_status: Option<DiffHunkStatus>,
1065    excerpt: &'a Excerpt,
1066    buffer_range: Range<BD>,
1067    range: Range<MBD>,
1068    has_trailing_newline: bool,
1069}
1070
1071struct ExcerptChunks<'a> {
1072    excerpt_id: ExcerptId,
1073    content_chunks: BufferChunks<'a>,
1074    has_footer: bool,
1075}
1076
1077#[derive(Debug)]
1078struct BufferEdit {
1079    range: Range<BufferOffset>,
1080    new_text: Arc<str>,
1081    is_insertion: bool,
1082    original_indent_column: Option<u32>,
1083    excerpt_id: ExcerptId,
1084}
1085
1086#[derive(Clone, Copy, Debug, PartialEq)]
1087enum DiffChangeKind {
1088    BufferEdited,
1089    DiffUpdated { base_changed: bool },
1090    ExpandOrCollapseHunks { expand: bool },
1091}
1092
1093#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1094pub enum ExpandExcerptDirection {
1095    Up,
1096    Down,
1097    UpAndDown,
1098}
1099
1100impl ExpandExcerptDirection {
1101    pub fn should_expand_up(&self) -> bool {
1102        match self {
1103            ExpandExcerptDirection::Up => true,
1104            ExpandExcerptDirection::Down => false,
1105            ExpandExcerptDirection::UpAndDown => true,
1106        }
1107    }
1108
1109    pub fn should_expand_down(&self) -> bool {
1110        match self {
1111            ExpandExcerptDirection::Up => false,
1112            ExpandExcerptDirection::Down => true,
1113            ExpandExcerptDirection::UpAndDown => true,
1114        }
1115    }
1116}
1117
1118#[derive(Clone, Debug, PartialEq)]
1119pub struct IndentGuide {
1120    pub buffer_id: BufferId,
1121    pub start_row: MultiBufferRow,
1122    pub end_row: MultiBufferRow,
1123    pub depth: u32,
1124    pub tab_size: u32,
1125    pub settings: IndentGuideSettings,
1126}
1127
1128impl IndentGuide {
1129    pub fn indent_level(&self) -> u32 {
1130        self.depth * self.tab_size
1131    }
1132}
1133
1134impl MultiBuffer {
1135    pub fn new(capability: Capability) -> Self {
1136        Self::new_(
1137            capability,
1138            MultiBufferSnapshot {
1139                show_headers: true,
1140                show_deleted_hunks: true,
1141                ..MultiBufferSnapshot::default()
1142            },
1143        )
1144    }
1145
1146    pub fn without_headers(capability: Capability) -> Self {
1147        Self::new_(
1148            capability,
1149            MultiBufferSnapshot {
1150                show_deleted_hunks: true,
1151                ..MultiBufferSnapshot::default()
1152            },
1153        )
1154    }
1155
1156    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1157        let mut this = Self::new_(
1158            buffer.read(cx).capability(),
1159            MultiBufferSnapshot {
1160                singleton: true,
1161                show_deleted_hunks: true,
1162                ..MultiBufferSnapshot::default()
1163            },
1164        );
1165        this.singleton = true;
1166        this.set_excerpts_for_path(
1167            PathKey::sorted(0),
1168            buffer.clone(),
1169            [Point::zero()..buffer.read(cx).max_point()],
1170            0,
1171            cx,
1172        );
1173        this
1174    }
1175
1176    #[inline]
1177    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1178        Self {
1179            snapshot: RefCell::new(snapshot),
1180            buffers: Default::default(),
1181            diffs: HashMap::default(),
1182            subscriptions: Topic::default(),
1183            singleton: false,
1184            capability,
1185            title: None,
1186            excerpts_by_path: Default::default(),
1187            paths_by_excerpt: Default::default(),
1188            buffer_changed_since_sync: Default::default(),
1189            history: History::default(),
1190        }
1191    }
1192
1193    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1194        let mut buffers = BTreeMap::default();
1195        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1196        for (buffer_id, buffer_state) in self.buffers.iter() {
1197            buffer_state.buffer.update(new_cx, |buffer, _| {
1198                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1199            });
1200            buffers.insert(
1201                *buffer_id,
1202                BufferState {
1203                    buffer: buffer_state.buffer.clone(),
1204                    last_version: buffer_state.last_version.clone(),
1205                    last_non_text_state_update_count: buffer_state
1206                        .last_non_text_state_update_count
1207                        .clone(),
1208                    excerpts: buffer_state.excerpts.clone(),
1209                    _subscriptions: [
1210                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1211                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1212                    ],
1213                },
1214            );
1215        }
1216        let mut diff_bases = HashMap::default();
1217        for (buffer_id, diff) in self.diffs.iter() {
1218            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1219        }
1220        Self {
1221            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1222            buffers,
1223            excerpts_by_path: Default::default(),
1224            paths_by_excerpt: Default::default(),
1225            diffs: diff_bases,
1226            subscriptions: Default::default(),
1227            singleton: self.singleton,
1228            capability: self.capability,
1229            history: self.history.clone(),
1230            title: self.title.clone(),
1231            buffer_changed_since_sync,
1232        }
1233    }
1234
1235    pub fn set_group_interval(&mut self, group_interval: Duration) {
1236        self.history.set_group_interval(group_interval);
1237    }
1238
1239    pub fn with_title(mut self, title: String) -> Self {
1240        self.title = Some(title);
1241        self
1242    }
1243
1244    pub fn read_only(&self) -> bool {
1245        !self.capability.editable()
1246    }
1247
1248    pub fn capability(&self) -> Capability {
1249        self.capability
1250    }
1251
1252    /// Returns an up-to-date snapshot of the MultiBuffer.
1253    #[ztracing::instrument(skip_all)]
1254    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1255        self.sync(cx);
1256        self.snapshot.borrow().clone()
1257    }
1258
1259    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1260        self.sync(cx);
1261        self.snapshot.borrow()
1262    }
1263
1264    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1265        if self.singleton {
1266            Some(self.buffers.values().next().unwrap().buffer.clone())
1267        } else {
1268            None
1269        }
1270    }
1271
1272    pub fn is_singleton(&self) -> bool {
1273        self.singleton
1274    }
1275
1276    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1277        self.subscriptions.subscribe()
1278    }
1279
1280    pub fn is_dirty(&self, cx: &App) -> bool {
1281        self.read(cx).is_dirty()
1282    }
1283
1284    pub fn has_deleted_file(&self, cx: &App) -> bool {
1285        self.read(cx).has_deleted_file()
1286    }
1287
1288    pub fn has_conflict(&self, cx: &App) -> bool {
1289        self.read(cx).has_conflict()
1290    }
1291
1292    // The `is_empty` signature doesn't match what clippy expects
1293    #[allow(clippy::len_without_is_empty)]
1294    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1295        self.read(cx).len()
1296    }
1297
1298    pub fn is_empty(&self) -> bool {
1299        self.buffers.is_empty()
1300    }
1301
1302    pub fn edit<I, S, T>(
1303        &mut self,
1304        edits: I,
1305        autoindent_mode: Option<AutoindentMode>,
1306        cx: &mut Context<Self>,
1307    ) where
1308        I: IntoIterator<Item = (Range<S>, T)>,
1309        S: ToOffset,
1310        T: Into<Arc<str>>,
1311    {
1312        self.edit_internal(edits, autoindent_mode, true, cx);
1313    }
1314
1315    pub fn edit_non_coalesce<I, S, T>(
1316        &mut self,
1317        edits: I,
1318        autoindent_mode: Option<AutoindentMode>,
1319        cx: &mut Context<Self>,
1320    ) where
1321        I: IntoIterator<Item = (Range<S>, T)>,
1322        S: ToOffset,
1323        T: Into<Arc<str>>,
1324    {
1325        self.edit_internal(edits, autoindent_mode, false, cx);
1326    }
1327
1328    fn edit_internal<I, S, T>(
1329        &mut self,
1330        edits: I,
1331        autoindent_mode: Option<AutoindentMode>,
1332        coalesce_adjacent: bool,
1333        cx: &mut Context<Self>,
1334    ) where
1335        I: IntoIterator<Item = (Range<S>, T)>,
1336        S: ToOffset,
1337        T: Into<Arc<str>>,
1338    {
1339        if self.read_only() || self.buffers.is_empty() {
1340            return;
1341        }
1342        self.sync_mut(cx);
1343        let edits = edits
1344            .into_iter()
1345            .map(|(range, new_text)| {
1346                let mut range = range.start.to_offset(self.snapshot.get_mut())
1347                    ..range.end.to_offset(self.snapshot.get_mut());
1348                if range.start > range.end {
1349                    mem::swap(&mut range.start, &mut range.end);
1350                }
1351                (range, new_text.into())
1352            })
1353            .collect::<Vec<_>>();
1354
1355        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1356
1357        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1358        fn edit_internal(
1359            this: &mut MultiBuffer,
1360            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1361            mut autoindent_mode: Option<AutoindentMode>,
1362            coalesce_adjacent: bool,
1363            cx: &mut Context<MultiBuffer>,
1364        ) {
1365            let original_indent_columns = match &mut autoindent_mode {
1366                Some(AutoindentMode::Block {
1367                    original_indent_columns,
1368                }) => mem::take(original_indent_columns),
1369                _ => Default::default(),
1370            };
1371
1372            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1373                edits,
1374                this.snapshot.get_mut(),
1375                &original_indent_columns,
1376            );
1377
1378            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1379            for (buffer_id, mut edits) in buffer_edits {
1380                buffer_ids.push(buffer_id);
1381                edits.sort_by_key(|edit| edit.range.start);
1382                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1383                    let mut edits = edits.into_iter().peekable();
1384                    let mut insertions = Vec::new();
1385                    let mut original_indent_columns = Vec::new();
1386                    let mut deletions = Vec::new();
1387                    let empty_str: Arc<str> = Arc::default();
1388                    while let Some(BufferEdit {
1389                        mut range,
1390                        mut new_text,
1391                        mut is_insertion,
1392                        original_indent_column,
1393                        excerpt_id,
1394                    }) = edits.next()
1395                    {
1396                        while let Some(BufferEdit {
1397                            range: next_range,
1398                            is_insertion: next_is_insertion,
1399                            new_text: next_new_text,
1400                            excerpt_id: next_excerpt_id,
1401                            ..
1402                        }) = edits.peek()
1403                        {
1404                            let should_coalesce = if coalesce_adjacent {
1405                                range.end >= next_range.start
1406                            } else {
1407                                range.end > next_range.start
1408                            };
1409
1410                            if should_coalesce {
1411                                range.end = cmp::max(next_range.end, range.end);
1412                                is_insertion |= *next_is_insertion;
1413                                if excerpt_id == *next_excerpt_id {
1414                                    new_text = format!("{new_text}{next_new_text}").into();
1415                                }
1416                                edits.next();
1417                            } else {
1418                                break;
1419                            }
1420                        }
1421
1422                        if is_insertion {
1423                            original_indent_columns.push(original_indent_column);
1424                            insertions.push((
1425                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1426                                new_text.clone(),
1427                            ));
1428                        } else if !range.is_empty() {
1429                            deletions.push((
1430                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1431                                empty_str.clone(),
1432                            ));
1433                        }
1434                    }
1435
1436                    let deletion_autoindent_mode =
1437                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1438                            Some(AutoindentMode::Block {
1439                                original_indent_columns: Default::default(),
1440                            })
1441                        } else {
1442                            autoindent_mode.clone()
1443                        };
1444                    let insertion_autoindent_mode =
1445                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1446                            Some(AutoindentMode::Block {
1447                                original_indent_columns,
1448                            })
1449                        } else {
1450                            autoindent_mode.clone()
1451                        };
1452
1453                    if coalesce_adjacent {
1454                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1455                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1456                    } else {
1457                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1458                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1459                    }
1460                })
1461            }
1462
1463            cx.emit(Event::ExcerptsEdited {
1464                excerpt_ids: edited_excerpt_ids,
1465                buffer_ids,
1466            });
1467        }
1468    }
1469
1470    fn convert_edits_to_buffer_edits(
1471        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1472        snapshot: &MultiBufferSnapshot,
1473        original_indent_columns: &[Option<u32>],
1474    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1475        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1476        let mut edited_excerpt_ids = Vec::new();
1477        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1478        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1479            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1480
1481            cursor.seek(&range.start);
1482            let mut start_region = cursor.region().expect("start offset out of bounds");
1483            if !start_region.is_main_buffer {
1484                cursor.next();
1485                if let Some(region) = cursor.region() {
1486                    start_region = region;
1487                } else {
1488                    continue;
1489                }
1490            }
1491
1492            if range.end < start_region.range.start {
1493                continue;
1494            }
1495
1496            let start_region = start_region.clone();
1497            if range.end > start_region.range.end {
1498                cursor.seek_forward(&range.end);
1499            }
1500            let mut end_region = cursor.region().expect("end offset out of bounds");
1501            if !end_region.is_main_buffer {
1502                cursor.prev();
1503                if let Some(region) = cursor.region() {
1504                    end_region = region;
1505                } else {
1506                    continue;
1507                }
1508            }
1509
1510            if range.start > end_region.range.end {
1511                continue;
1512            }
1513
1514            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1515            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1516            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1517                .min(start_region.buffer_range.end);
1518            let buffer_end =
1519                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1520
1521            if start_region.excerpt.id == end_region.excerpt.id {
1522                if start_region.buffer.capability == Capability::ReadWrite
1523                    && start_region.is_main_buffer
1524                {
1525                    edited_excerpt_ids.push(start_region.excerpt.id);
1526                    buffer_edits
1527                        .entry(start_region.buffer.remote_id())
1528                        .or_default()
1529                        .push(BufferEdit {
1530                            range: buffer_start..buffer_end,
1531                            new_text,
1532                            is_insertion: true,
1533                            original_indent_column,
1534                            excerpt_id: start_region.excerpt.id,
1535                        });
1536                }
1537            } else {
1538                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1539                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1540                if start_region.buffer.capability == Capability::ReadWrite
1541                    && start_region.is_main_buffer
1542                {
1543                    edited_excerpt_ids.push(start_region.excerpt.id);
1544                    buffer_edits
1545                        .entry(start_region.buffer.remote_id())
1546                        .or_default()
1547                        .push(BufferEdit {
1548                            range: start_excerpt_range,
1549                            new_text: new_text.clone(),
1550                            is_insertion: true,
1551                            original_indent_column,
1552                            excerpt_id: start_region.excerpt.id,
1553                        });
1554                }
1555                let excerpt_id = end_region.excerpt.id;
1556                if end_region.buffer.capability == Capability::ReadWrite
1557                    && end_region.is_main_buffer
1558                {
1559                    edited_excerpt_ids.push(excerpt_id);
1560                    buffer_edits
1561                        .entry(end_region.buffer.remote_id())
1562                        .or_default()
1563                        .push(BufferEdit {
1564                            range: end_excerpt_range,
1565                            new_text: new_text.clone(),
1566                            is_insertion: false,
1567                            original_indent_column,
1568                            excerpt_id,
1569                        });
1570                }
1571
1572                cursor.seek(&range.start);
1573                cursor.next_excerpt();
1574                while let Some(region) = cursor.region() {
1575                    if region.excerpt.id == excerpt_id {
1576                        break;
1577                    }
1578                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1579                        edited_excerpt_ids.push(region.excerpt.id);
1580                        buffer_edits
1581                            .entry(region.buffer.remote_id())
1582                            .or_default()
1583                            .push(BufferEdit {
1584                                range: region.buffer_range.clone(),
1585                                new_text: new_text.clone(),
1586                                is_insertion: false,
1587                                original_indent_column,
1588                                excerpt_id: region.excerpt.id,
1589                            });
1590                    }
1591                    cursor.next_excerpt();
1592                }
1593            }
1594        }
1595        (buffer_edits, edited_excerpt_ids)
1596    }
1597
1598    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1599    where
1600        I: IntoIterator<Item = Range<S>>,
1601        S: ToOffset,
1602    {
1603        if self.read_only() || self.buffers.is_empty() {
1604            return;
1605        }
1606        self.sync_mut(cx);
1607        let empty = Arc::<str>::from("");
1608        let edits = ranges
1609            .into_iter()
1610            .map(|range| {
1611                let mut range = range.start.to_offset(self.snapshot.get_mut())
1612                    ..range.end.to_offset(&self.snapshot.get_mut());
1613                if range.start > range.end {
1614                    mem::swap(&mut range.start, &mut range.end);
1615                }
1616                (range, empty.clone())
1617            })
1618            .collect::<Vec<_>>();
1619
1620        return autoindent_ranges_internal(self, edits, cx);
1621
1622        fn autoindent_ranges_internal(
1623            this: &mut MultiBuffer,
1624            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1625            cx: &mut Context<MultiBuffer>,
1626        ) {
1627            let (buffer_edits, edited_excerpt_ids) =
1628                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1629
1630            let mut buffer_ids = Vec::new();
1631            for (buffer_id, mut edits) in buffer_edits {
1632                buffer_ids.push(buffer_id);
1633                edits.sort_unstable_by_key(|edit| edit.range.start);
1634
1635                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1636                for edit in edits {
1637                    if let Some(last_range) = ranges.last_mut()
1638                        && edit.range.start <= last_range.end
1639                    {
1640                        last_range.end = last_range.end.max(edit.range.end);
1641                        continue;
1642                    }
1643                    ranges.push(edit.range);
1644                }
1645
1646                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1647                    buffer.autoindent_ranges(ranges, cx);
1648                })
1649            }
1650
1651            cx.emit(Event::ExcerptsEdited {
1652                excerpt_ids: edited_excerpt_ids,
1653                buffer_ids,
1654            });
1655        }
1656    }
1657
1658    pub fn set_active_selections(
1659        &self,
1660        selections: &[Selection<Anchor>],
1661        line_mode: bool,
1662        cursor_shape: CursorShape,
1663        cx: &mut Context<Self>,
1664    ) {
1665        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1666            Default::default();
1667        let snapshot = self.read(cx);
1668        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1669        for selection in selections {
1670            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1671            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1672
1673            cursor.seek(&Some(start_locator), Bias::Left);
1674            while let Some(excerpt) = cursor.item()
1675                && excerpt.locator <= *end_locator
1676            {
1677                let mut start = excerpt.range.context.start;
1678                let mut end = excerpt.range.context.end;
1679                if excerpt.id == selection.start.excerpt_id {
1680                    start = selection.start.text_anchor;
1681                }
1682                if excerpt.id == selection.end.excerpt_id {
1683                    end = selection.end.text_anchor;
1684                }
1685                selections_by_buffer
1686                    .entry(excerpt.buffer_id)
1687                    .or_default()
1688                    .push(Selection {
1689                        id: selection.id,
1690                        start,
1691                        end,
1692                        reversed: selection.reversed,
1693                        goal: selection.goal,
1694                    });
1695
1696                cursor.next();
1697            }
1698        }
1699
1700        for (buffer_id, buffer_state) in self.buffers.iter() {
1701            if !selections_by_buffer.contains_key(buffer_id) {
1702                buffer_state
1703                    .buffer
1704                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1705            }
1706        }
1707
1708        for (buffer_id, mut selections) in selections_by_buffer {
1709            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1710                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1711                let mut selections = selections.into_iter().peekable();
1712                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1713                    let mut selection = selections.next()?;
1714                    while let Some(next_selection) = selections.peek() {
1715                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1716                            let next_selection = selections.next().unwrap();
1717                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1718                                selection.end = next_selection.end;
1719                            }
1720                        } else {
1721                            break;
1722                        }
1723                    }
1724                    Some(selection)
1725                }));
1726                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1727            });
1728        }
1729    }
1730
1731    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1732        for buffer in self.buffers.values() {
1733            buffer
1734                .buffer
1735                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1736        }
1737    }
1738
1739    #[instrument(skip_all)]
1740    fn merge_excerpt_ranges<'a>(
1741        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1742    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1743        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1744        let mut counts: Vec<usize> = Vec::new();
1745        for range in expanded_ranges {
1746            if let Some(last_range) = merged_ranges.last_mut() {
1747                assert!(
1748                    last_range.context.start <= range.context.start,
1749                    "ranges must be sorted: {last_range:?} <= {range:?}"
1750                );
1751                if last_range.context.end >= range.context.start
1752                    || last_range.context.end.row + 1 == range.context.start.row
1753                {
1754                    last_range.context.end = range.context.end.max(last_range.context.end);
1755                    *counts.last_mut().unwrap() += 1;
1756                    continue;
1757                }
1758            }
1759            merged_ranges.push(range.clone());
1760            counts.push(1);
1761        }
1762        (merged_ranges, counts)
1763    }
1764
1765    pub fn insert_excerpts_after<O>(
1766        &mut self,
1767        prev_excerpt_id: ExcerptId,
1768        buffer: Entity<Buffer>,
1769        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1770        cx: &mut Context<Self>,
1771    ) -> Vec<ExcerptId>
1772    where
1773        O: text::ToOffset,
1774    {
1775        let mut ids = Vec::new();
1776        let mut next_excerpt_id =
1777            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1778                last_entry.id.0 + 1
1779            } else {
1780                1
1781            };
1782        self.insert_excerpts_with_ids_after(
1783            prev_excerpt_id,
1784            buffer,
1785            ranges.into_iter().map(|range| {
1786                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1787                ids.push(id);
1788                (id, range)
1789            }),
1790            cx,
1791        );
1792        ids
1793    }
1794
1795    pub fn insert_excerpts_with_ids_after<O>(
1796        &mut self,
1797        prev_excerpt_id: ExcerptId,
1798        buffer: Entity<Buffer>,
1799        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1800        cx: &mut Context<Self>,
1801    ) where
1802        O: text::ToOffset,
1803    {
1804        assert_eq!(self.history.transaction_depth(), 0);
1805        let mut ranges = ranges.into_iter().peekable();
1806        if ranges.peek().is_none() {
1807            return Default::default();
1808        }
1809
1810        self.sync_mut(cx);
1811
1812        let buffer_snapshot = buffer.read(cx).snapshot();
1813        let buffer_id = buffer_snapshot.remote_id();
1814
1815        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1816            self.buffer_changed_since_sync.replace(true);
1817            buffer.update(cx, |buffer, _| {
1818                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1819            });
1820            BufferState {
1821                last_version: RefCell::new(buffer_snapshot.version().clone()),
1822                last_non_text_state_update_count: Cell::new(
1823                    buffer_snapshot.non_text_state_update_count(),
1824                ),
1825                excerpts: Default::default(),
1826                _subscriptions: [
1827                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1828                    cx.subscribe(&buffer, Self::on_buffer_event),
1829                ],
1830                buffer: buffer.clone(),
1831            }
1832        });
1833
1834        let mut snapshot = self.snapshot.get_mut();
1835
1836        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1837        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1838        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1839        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1840        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1841
1842        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1843        new_excerpts.update_last(
1844            |excerpt| {
1845                excerpt.has_trailing_newline = true;
1846            },
1847            (),
1848        );
1849
1850        let next_locator = if let Some(excerpt) = cursor.item() {
1851            excerpt.locator.clone()
1852        } else {
1853            Locator::max()
1854        };
1855
1856        let mut excerpts = Vec::new();
1857        let buffer_snapshot = Arc::new(buffer_snapshot);
1858        while let Some((id, range)) = ranges.next() {
1859            let locator = Locator::between(&prev_locator, &next_locator);
1860            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1861                buffer_state.excerpts.insert(ix, locator.clone());
1862            }
1863            let range = ExcerptRange {
1864                context: buffer_snapshot.anchor_before(&range.context.start)
1865                    ..buffer_snapshot.anchor_after(&range.context.end),
1866                primary: buffer_snapshot.anchor_before(&range.primary.start)
1867                    ..buffer_snapshot.anchor_after(&range.primary.end),
1868            };
1869            excerpts.push((id, range.clone()));
1870            let excerpt = Excerpt::new(
1871                id,
1872                locator.clone(),
1873                buffer_id,
1874                buffer_snapshot.clone(),
1875                range,
1876                ranges.peek().is_some() || cursor.item().is_some(),
1877            );
1878            new_excerpts.push(excerpt, ());
1879            prev_locator = locator.clone();
1880
1881            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1882                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1883            }
1884            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1885        }
1886        snapshot
1887            .buffer_locators
1888            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1889
1890        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1891
1892        let suffix = cursor.suffix();
1893        let changed_trailing_excerpt = suffix.is_empty();
1894        new_excerpts.append(suffix, ());
1895        drop(cursor);
1896        snapshot.excerpts = new_excerpts;
1897        snapshot.excerpt_ids = new_excerpt_ids;
1898        if changed_trailing_excerpt {
1899            snapshot.trailing_excerpt_update_count += 1;
1900        }
1901
1902        let edits = Self::sync_diff_transforms(
1903            &mut snapshot,
1904            vec![Edit {
1905                old: edit_start..edit_start,
1906                new: edit_start..edit_end,
1907            }],
1908            DiffChangeKind::BufferEdited,
1909        );
1910        if !edits.is_empty() {
1911            self.subscriptions.publish(edits);
1912        }
1913
1914        cx.emit(Event::Edited {
1915            edited_buffer: None,
1916            is_local: true,
1917        });
1918        cx.emit(Event::ExcerptsAdded {
1919            buffer,
1920            predecessor: prev_excerpt_id,
1921            excerpts,
1922        });
1923        cx.notify();
1924    }
1925
1926    pub fn clear(&mut self, cx: &mut Context<Self>) {
1927        self.sync_mut(cx);
1928        let ids = self.excerpt_ids();
1929        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1930        self.excerpts_by_path.clear();
1931        self.paths_by_excerpt.clear();
1932        let MultiBufferSnapshot {
1933            excerpts,
1934            buffer_locators,
1935            diffs: _,
1936            diff_transforms: _,
1937            non_text_state_update_count: _,
1938            edit_count: _,
1939            is_dirty,
1940            has_deleted_file,
1941            has_conflict,
1942            has_inverted_diff,
1943            singleton: _,
1944            excerpt_ids: _,
1945            replaced_excerpts,
1946            trailing_excerpt_update_count,
1947            all_diff_hunks_expanded: _,
1948            show_deleted_hunks: _,
1949            use_extended_diff_range: _,
1950            show_headers: _,
1951        } = self.snapshot.get_mut();
1952        buffer_locators.clear();
1953        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1954        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1955        *excerpts = Default::default();
1956        *trailing_excerpt_update_count += 1;
1957        *is_dirty = false;
1958        *has_deleted_file = false;
1959        *has_conflict = false;
1960        *has_inverted_diff = false;
1961        match Arc::get_mut(replaced_excerpts) {
1962            Some(replaced_excerpts) => replaced_excerpts.clear(),
1963            None => *replaced_excerpts = Default::default(),
1964        }
1965
1966        let edits = Self::sync_diff_transforms(
1967            self.snapshot.get_mut(),
1968            vec![Edit {
1969                old: start..prev_len,
1970                new: start..start,
1971            }],
1972            DiffChangeKind::BufferEdited,
1973        );
1974        if !edits.is_empty() {
1975            self.subscriptions.publish(edits);
1976        }
1977        cx.emit(Event::Edited {
1978            edited_buffer: None,
1979            is_local: true,
1980        });
1981        cx.emit(Event::ExcerptsRemoved {
1982            ids,
1983            removed_buffer_ids,
1984        });
1985        cx.notify();
1986    }
1987
1988    #[ztracing::instrument(skip_all)]
1989    pub fn excerpts_for_buffer(
1990        &self,
1991        buffer_id: BufferId,
1992        cx: &App,
1993    ) -> Vec<(ExcerptId, Arc<BufferSnapshot>, ExcerptRange<text::Anchor>)> {
1994        let mut excerpts = Vec::new();
1995        let snapshot = self.read(cx);
1996        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1997        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1998            for locator in &**locators {
1999                cursor.seek_forward(&Some(locator), Bias::Left);
2000                if let Some(excerpt) = cursor.item()
2001                    && excerpt.locator == *locator
2002                {
2003                    excerpts.push((excerpt.id, excerpt.buffer.clone(), excerpt.range.clone()));
2004                }
2005            }
2006        }
2007
2008        excerpts
2009    }
2010
2011    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2012        let snapshot = self.read(cx);
2013        let mut excerpts = snapshot
2014            .excerpts
2015            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2016        let mut diff_transforms = snapshot
2017            .diff_transforms
2018            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2019        diff_transforms.next();
2020        let locators = snapshot
2021            .buffer_locators
2022            .get(&buffer_id)
2023            .into_iter()
2024            .flat_map(|v| &**v);
2025        let mut result = Vec::new();
2026        for locator in locators {
2027            excerpts.seek_forward(&Some(locator), Bias::Left);
2028            if let Some(excerpt) = excerpts.item()
2029                && excerpt.locator == *locator
2030            {
2031                let excerpt_start = excerpts.start().1;
2032                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2033
2034                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2035                let overshoot = excerpt_start - diff_transforms.start().0;
2036                let start = diff_transforms.start().1 + overshoot;
2037
2038                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2039                let overshoot = excerpt_end - diff_transforms.start().0;
2040                let end = diff_transforms.start().1 + overshoot;
2041
2042                result.push(start.0..end.0)
2043            }
2044        }
2045        result
2046    }
2047
2048    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2049        self.snapshot
2050            .borrow()
2051            .excerpts
2052            .iter()
2053            .map(|entry| entry.buffer_id)
2054            .collect()
2055    }
2056
2057    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2058        let snapshot = self.snapshot.borrow();
2059        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2060        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2061        ids
2062    }
2063
2064    pub fn excerpt_containing(
2065        &self,
2066        position: impl ToOffset,
2067        cx: &App,
2068    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2069        let snapshot = self.read(cx);
2070        let offset = position.to_offset(&snapshot);
2071
2072        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2073        cursor.seek(&offset);
2074        cursor
2075            .excerpt()
2076            .or_else(|| snapshot.excerpts.last())
2077            .map(|excerpt| {
2078                (
2079                    excerpt.id,
2080                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2081                    excerpt.range.context.clone(),
2082                )
2083            })
2084    }
2085
2086    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2087        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2088            self.buffer(buffer_id)
2089        } else {
2090            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2091            Some(buffer)
2092        }
2093    }
2094
2095    // If point is at the end of the buffer, the last excerpt is returned
2096    pub fn point_to_buffer_offset<T: ToOffset>(
2097        &self,
2098        point: T,
2099        cx: &App,
2100    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2101        let snapshot = self.read(cx);
2102        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2103        Some((
2104            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2105            offset,
2106        ))
2107    }
2108
2109    // If point is at the end of the buffer, the last excerpt is returned
2110    pub fn point_to_buffer_point<T: ToPoint>(
2111        &self,
2112        point: T,
2113        cx: &App,
2114    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2115        let snapshot = self.read(cx);
2116        let (buffer, point, is_main_buffer) =
2117            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2118        Some((
2119            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2120            point,
2121            is_main_buffer,
2122        ))
2123    }
2124
2125    pub fn buffer_point_to_anchor(
2126        &self,
2127        // todo(lw): We shouldn't need this?
2128        buffer: &Entity<Buffer>,
2129        point: Point,
2130        cx: &App,
2131    ) -> Option<Anchor> {
2132        let mut found = None;
2133        let snapshot = buffer.read(cx).snapshot();
2134        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2135            let start = range.context.start.to_point(&snapshot);
2136            let end = range.context.end.to_point(&snapshot);
2137            if start <= point && point < end {
2138                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2139                break;
2140            }
2141            if point < start {
2142                found = Some((start, excerpt_id));
2143            }
2144            if point > end {
2145                found = Some((end, excerpt_id));
2146            }
2147        }
2148
2149        found.map(|(point, excerpt_id)| {
2150            let text_anchor = snapshot.anchor_after(point);
2151            Anchor::in_buffer(excerpt_id, text_anchor)
2152        })
2153    }
2154
2155    pub fn buffer_anchor_to_anchor(
2156        &self,
2157        // todo(lw): We shouldn't need this?
2158        buffer: &Entity<Buffer>,
2159        anchor: text::Anchor,
2160        cx: &App,
2161    ) -> Option<Anchor> {
2162        let snapshot = buffer.read(cx).snapshot();
2163        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2164            if range.context.start.cmp(&anchor, &snapshot).is_le()
2165                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2166            {
2167                return Some(Anchor::in_buffer(excerpt_id, anchor));
2168            }
2169        }
2170
2171        None
2172    }
2173
2174    pub fn merge_excerpts(
2175        &mut self,
2176        excerpt_ids: &[ExcerptId],
2177        cx: &mut Context<Self>,
2178    ) -> ExcerptId {
2179        debug_assert!(!excerpt_ids.is_empty());
2180        if excerpt_ids.len() == 1 {
2181            return excerpt_ids[0];
2182        }
2183
2184        let snapshot = self.snapshot(cx);
2185
2186        let first_range = snapshot
2187            .context_range_for_excerpt(excerpt_ids[0])
2188            .expect("first excerpt must exist");
2189        let last_range = snapshot
2190            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2191            .expect("last excerpt must exist");
2192
2193        let union_range = first_range.start..last_range.end;
2194
2195        drop(snapshot);
2196
2197        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2198        let removed = &excerpt_ids[1..];
2199        for &excerpt_id in removed {
2200            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2201                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2202                    excerpt_list.retain(|id| *id != excerpt_id);
2203                    if excerpt_list.is_empty() {
2204                        let path = path.clone();
2205                        self.excerpts_by_path.remove(&path);
2206                    }
2207                }
2208            }
2209        }
2210        self.remove_excerpts(removed.iter().copied(), cx);
2211
2212        excerpt_ids[0]
2213    }
2214
2215    pub fn remove_excerpts(
2216        &mut self,
2217        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2218        cx: &mut Context<Self>,
2219    ) {
2220        self.sync_mut(cx);
2221        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2222        if ids.is_empty() {
2223            return;
2224        }
2225        self.buffer_changed_since_sync.replace(true);
2226
2227        let mut snapshot = self.snapshot.get_mut();
2228        let mut new_excerpts = SumTree::default();
2229        let mut cursor = snapshot
2230            .excerpts
2231            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2232        let mut edits = Vec::new();
2233        let mut excerpt_ids = ids.iter().copied().peekable();
2234        let mut removed_buffer_ids = Vec::new();
2235        let mut removed_excerpts_for_buffers = HashSet::default();
2236
2237        while let Some(excerpt_id) = excerpt_ids.next() {
2238            self.paths_by_excerpt.remove(&excerpt_id);
2239            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2240            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2241            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2242
2243            if let Some(mut excerpt) = cursor.item() {
2244                if excerpt.id != excerpt_id {
2245                    continue;
2246                }
2247                let mut old_start = cursor.start().1;
2248
2249                // Skip over the removed excerpt.
2250                'remove_excerpts: loop {
2251                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2252                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2253                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2254                        if buffer_state.excerpts.is_empty() {
2255                            log::debug!(
2256                                "removing buffer and diff for buffer {}",
2257                                excerpt.buffer_id
2258                            );
2259                            self.buffers.remove(&excerpt.buffer_id);
2260                            removed_buffer_ids.push(excerpt.buffer_id);
2261                        }
2262                    }
2263                    cursor.next();
2264
2265                    // Skip over any subsequent excerpts that are also removed.
2266                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2267                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2268                        if let Some(next_excerpt) = cursor.item()
2269                            && next_excerpt.locator == *next_locator
2270                        {
2271                            excerpt_ids.next();
2272                            excerpt = next_excerpt;
2273                            continue 'remove_excerpts;
2274                        }
2275                    }
2276
2277                    break;
2278                }
2279
2280                // When removing the last excerpt, remove the trailing newline from
2281                // the previous excerpt.
2282                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2283                    old_start -= 1;
2284                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2285                }
2286
2287                // Push an edit for the removal of this run of excerpts.
2288                let old_end = cursor.start().1;
2289                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2290                edits.push(Edit {
2291                    old: old_start..old_end,
2292                    new: new_start..new_start,
2293                });
2294            }
2295        }
2296        let suffix = cursor.suffix();
2297        let changed_trailing_excerpt = suffix.is_empty();
2298        new_excerpts.append(suffix, ());
2299        drop(cursor);
2300        for buffer_id in removed_excerpts_for_buffers {
2301            match self.buffers.get(&buffer_id) {
2302                Some(buffer_state) => {
2303                    snapshot
2304                        .buffer_locators
2305                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2306                }
2307                None => {
2308                    snapshot.buffer_locators.remove(&buffer_id);
2309                }
2310            }
2311        }
2312        snapshot.excerpts = new_excerpts;
2313        for buffer_id in &removed_buffer_ids {
2314            self.diffs.remove(buffer_id);
2315            snapshot.diffs.remove(buffer_id);
2316        }
2317
2318        // Recalculate has_inverted_diff after removing diffs
2319        if !removed_buffer_ids.is_empty() {
2320            snapshot.has_inverted_diff = snapshot
2321                .diffs
2322                .iter()
2323                .any(|(_, diff)| diff.main_buffer.is_some());
2324        }
2325
2326        if changed_trailing_excerpt {
2327            snapshot.trailing_excerpt_update_count += 1;
2328        }
2329
2330        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2331        if !edits.is_empty() {
2332            self.subscriptions.publish(edits);
2333        }
2334        cx.emit(Event::Edited {
2335            edited_buffer: None,
2336            is_local: true,
2337        });
2338        cx.emit(Event::ExcerptsRemoved {
2339            ids,
2340            removed_buffer_ids,
2341        });
2342        cx.notify();
2343    }
2344
2345    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2346        &self,
2347        anchors: Anchors,
2348        cx: &mut Context<Self>,
2349    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2350        let mut error = None;
2351        let mut futures = Vec::new();
2352        for anchor in anchors {
2353            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2354                if let Some(buffer) = self.buffers.get(&buffer_id) {
2355                    buffer.buffer.update(cx, |buffer, _| {
2356                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2357                    });
2358                } else {
2359                    error = Some(anyhow!(
2360                        "buffer {buffer_id} is not part of this multi-buffer"
2361                    ));
2362                    break;
2363                }
2364            }
2365        }
2366        async move {
2367            if let Some(error) = error {
2368                Err(error)?;
2369            }
2370            for future in futures {
2371                future.await?;
2372            }
2373            Ok(())
2374        }
2375    }
2376
2377    pub fn text_anchor_for_position<T: ToOffset>(
2378        &self,
2379        position: T,
2380        cx: &App,
2381    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2382        let snapshot = self.read(cx);
2383        let anchor = snapshot.anchor_before(position);
2384        let buffer = self
2385            .buffers
2386            .get(&anchor.text_anchor.buffer_id?)?
2387            .buffer
2388            .clone();
2389        Some((buffer, anchor.text_anchor))
2390    }
2391
2392    fn on_buffer_event(
2393        &mut self,
2394        buffer: Entity<Buffer>,
2395        event: &language::BufferEvent,
2396        cx: &mut Context<Self>,
2397    ) {
2398        use language::BufferEvent;
2399        let buffer_id = buffer.read(cx).remote_id();
2400        cx.emit(match event {
2401            &BufferEvent::Edited { is_local } => Event::Edited {
2402                edited_buffer: Some(buffer),
2403                is_local,
2404            },
2405            BufferEvent::DirtyChanged => Event::DirtyChanged,
2406            BufferEvent::Saved => Event::Saved,
2407            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2408            BufferEvent::Reloaded => Event::Reloaded,
2409            BufferEvent::LanguageChanged(has_language) => {
2410                Event::LanguageChanged(buffer_id, *has_language)
2411            }
2412            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2413            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2414            BufferEvent::CapabilityChanged => {
2415                self.capability = buffer.read(cx).capability();
2416                return;
2417            }
2418            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2419        });
2420    }
2421
2422    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2423        let diff = diff.read(cx);
2424        let buffer_id = diff.buffer_id;
2425        let diff = DiffStateSnapshot {
2426            diff: diff.snapshot(cx),
2427            main_buffer: None,
2428        };
2429        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2430    }
2431
2432    fn inverted_buffer_diff_language_changed(
2433        &mut self,
2434        diff: Entity<BufferDiff>,
2435        main_buffer: Entity<language::Buffer>,
2436        cx: &mut Context<Self>,
2437    ) {
2438        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2439        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2440        let diff = diff.read(cx);
2441        let diff = DiffStateSnapshot {
2442            diff: diff.snapshot(cx),
2443            main_buffer: Some(main_buffer_snapshot),
2444        };
2445        self.snapshot
2446            .get_mut()
2447            .diffs
2448            .insert(base_text_buffer_id, diff);
2449    }
2450
2451    fn buffer_diff_changed(
2452        &mut self,
2453        diff: Entity<BufferDiff>,
2454        range: Range<text::Anchor>,
2455        cx: &mut Context<Self>,
2456    ) {
2457        self.sync_mut(cx);
2458
2459        let diff = diff.read(cx);
2460        let buffer_id = diff.buffer_id;
2461
2462        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2463            return;
2464        };
2465        let new_diff = DiffStateSnapshot {
2466            diff: diff.snapshot(cx),
2467            main_buffer: None,
2468        };
2469        let mut snapshot = self.snapshot.get_mut();
2470        let base_text_changed = snapshot
2471            .diffs
2472            .get(&buffer_id)
2473            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2474        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2475
2476        let buffer = buffer_state.buffer.read(cx);
2477        let diff_change_range = range.to_offset(buffer);
2478
2479        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2480        let edits = Self::sync_diff_transforms(
2481            &mut snapshot,
2482            excerpt_edits,
2483            DiffChangeKind::DiffUpdated {
2484                base_changed: base_text_changed,
2485            },
2486        );
2487        if !edits.is_empty() {
2488            self.subscriptions.publish(edits);
2489        }
2490        cx.emit(Event::Edited {
2491            edited_buffer: None,
2492            is_local: true,
2493        });
2494    }
2495
2496    fn inverted_buffer_diff_changed(
2497        &mut self,
2498        diff: Entity<BufferDiff>,
2499        main_buffer: Entity<language::Buffer>,
2500        diff_change_range: Option<Range<usize>>,
2501        cx: &mut Context<Self>,
2502    ) {
2503        self.sync_mut(cx);
2504
2505        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2506        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2507            return;
2508        };
2509
2510        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2511        let diff = diff.read(cx);
2512        let new_diff = DiffStateSnapshot {
2513            diff: diff.snapshot(cx),
2514            main_buffer: Some(main_buffer_snapshot),
2515        };
2516        let mut snapshot = self.snapshot.get_mut();
2517        snapshot
2518            .diffs
2519            .insert_or_replace(base_text_buffer_id, new_diff);
2520
2521        let Some(diff_change_range) = diff_change_range else {
2522            return;
2523        };
2524
2525        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2526        let edits = Self::sync_diff_transforms(
2527            &mut snapshot,
2528            excerpt_edits,
2529            DiffChangeKind::DiffUpdated {
2530                // We don't read this field for inverted diffs.
2531                base_changed: false,
2532            },
2533        );
2534        if !edits.is_empty() {
2535            self.subscriptions.publish(edits);
2536        }
2537        cx.emit(Event::Edited {
2538            edited_buffer: None,
2539            is_local: true,
2540        });
2541    }
2542
2543    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2544        self.buffers.values().map(|state| state.buffer.clone())
2545    }
2546
2547    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2548        self.all_buffers_iter().collect()
2549    }
2550
2551    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2552        self.buffers.keys().copied()
2553    }
2554
2555    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2556        self.all_buffer_ids_iter().collect()
2557    }
2558
2559    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2560        self.buffers
2561            .get(&buffer_id)
2562            .map(|state| state.buffer.clone())
2563    }
2564
2565    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2566        self.point_to_buffer_offset(point, cx)
2567            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2568    }
2569
2570    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2571        let buffer_id = self
2572            .snapshot
2573            .borrow()
2574            .excerpts
2575            .first()
2576            .map(|excerpt| excerpt.buffer.remote_id());
2577        buffer_id
2578            .and_then(|buffer_id| self.buffer(buffer_id))
2579            .map(|buffer| {
2580                let buffer = buffer.read(cx);
2581                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2582            })
2583            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2584    }
2585
2586    pub fn language_settings_at<'a, T: ToOffset>(
2587        &'a self,
2588        point: T,
2589        cx: &'a App,
2590    ) -> Cow<'a, LanguageSettings> {
2591        let mut language = None;
2592        let mut file = None;
2593        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2594            let buffer = buffer.read(cx);
2595            language = buffer.language_at(offset);
2596            file = buffer.file();
2597        }
2598        language_settings(language.map(|l| l.name()), file, cx)
2599    }
2600
2601    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2602        self.buffers.values().for_each(|state| f(&state.buffer))
2603    }
2604
2605    pub fn explicit_title(&self) -> Option<&str> {
2606        self.title.as_deref()
2607    }
2608
2609    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2610        if let Some(title) = self.title.as_ref() {
2611            return title.into();
2612        }
2613
2614        if let Some(buffer) = self.as_singleton() {
2615            let buffer = buffer.read(cx);
2616
2617            if let Some(file) = buffer.file() {
2618                return file.file_name(cx).into();
2619            }
2620
2621            if let Some(title) = self.buffer_content_title(buffer) {
2622                return title;
2623            }
2624        };
2625
2626        "untitled".into()
2627    }
2628
2629    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2630        let mut is_leading_whitespace = true;
2631        let mut count = 0;
2632        let mut prev_was_space = false;
2633        let mut title = String::new();
2634
2635        for ch in buffer.snapshot().chars() {
2636            if is_leading_whitespace && ch.is_whitespace() {
2637                continue;
2638            }
2639
2640            is_leading_whitespace = false;
2641
2642            if ch == '\n' || count >= 40 {
2643                break;
2644            }
2645
2646            if ch.is_whitespace() {
2647                if !prev_was_space {
2648                    title.push(' ');
2649                    count += 1;
2650                    prev_was_space = true;
2651                }
2652            } else {
2653                title.push(ch);
2654                count += 1;
2655                prev_was_space = false;
2656            }
2657        }
2658
2659        let title = title.trim_end().to_string();
2660
2661        if title.is_empty() {
2662            return None;
2663        }
2664
2665        Some(title.into())
2666    }
2667
2668    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2669        self.title = Some(title);
2670        cx.notify();
2671    }
2672
2673    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2674    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2675        for buffer_state in self.buffers.values() {
2676            buffer_state
2677                .buffer
2678                .update(cx, |buffer, _cx| buffer.refresh_preview());
2679        }
2680    }
2681
2682    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2683    pub fn preserve_preview(&self, cx: &App) -> bool {
2684        self.buffers
2685            .values()
2686            .all(|state| state.buffer.read(cx).preserve_preview())
2687    }
2688
2689    #[cfg(any(test, feature = "test-support"))]
2690    pub fn is_parsing(&self, cx: &App) -> bool {
2691        self.as_singleton().unwrap().read(cx).is_parsing()
2692    }
2693
2694    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2695        let buffer_id = diff.read(cx).buffer_id;
2696
2697        if let Some(existing_diff) = self.diff_for(buffer_id)
2698            && diff.entity_id() == existing_diff.entity_id()
2699        {
2700            return;
2701        }
2702
2703        self.buffer_diff_changed(
2704            diff.clone(),
2705            text::Anchor::min_max_range_for_buffer(buffer_id),
2706            cx,
2707        );
2708        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2709    }
2710
2711    pub fn add_inverted_diff(
2712        &mut self,
2713        diff: Entity<BufferDiff>,
2714        main_buffer: Entity<language::Buffer>,
2715        cx: &mut Context<Self>,
2716    ) {
2717        let snapshot = diff.read(cx).base_text(cx);
2718        let base_text_buffer_id = snapshot.remote_id();
2719        let diff_change_range = 0..snapshot.len();
2720        self.snapshot.get_mut().has_inverted_diff = true;
2721        self.inverted_buffer_diff_changed(
2722            diff.clone(),
2723            main_buffer.clone(),
2724            Some(diff_change_range),
2725            cx,
2726        );
2727        self.diffs.insert(
2728            base_text_buffer_id,
2729            DiffState::new_inverted(diff, main_buffer, cx),
2730        );
2731    }
2732
2733    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2734        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2735    }
2736
2737    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2738        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2739    }
2740
2741    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2742        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2743    }
2744
2745    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2746        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2747        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2748    }
2749
2750    pub fn all_diff_hunks_expanded(&self) -> bool {
2751        self.snapshot.borrow().all_diff_hunks_expanded
2752    }
2753
2754    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2755        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2756        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2757    }
2758
2759    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2760        self.snapshot.get_mut().show_deleted_hunks = show;
2761
2762        self.sync_mut(cx);
2763
2764        let old_len = self.snapshot.borrow().len();
2765
2766        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2767        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2768
2769        let new_len = self.snapshot.borrow().len();
2770
2771        self.subscriptions.publish(vec![Edit {
2772            old: MultiBufferOffset(0)..old_len,
2773            new: MultiBufferOffset(0)..new_len,
2774        }]);
2775
2776        cx.emit(Event::DiffHunksToggled);
2777        cx.emit(Event::Edited {
2778            edited_buffer: None,
2779            is_local: true,
2780        });
2781    }
2782
2783    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2784        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2785    }
2786
2787    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2788        self.read(cx)
2789            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2790            .nth(1)
2791            .is_some()
2792    }
2793
2794    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2795        let snapshot = self.read(cx);
2796        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2797        let offset_range = range.to_offset(&snapshot);
2798        cursor.seek(&offset_range.start, Bias::Left);
2799        while let Some(item) = cursor.item() {
2800            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2801                break;
2802            }
2803            if item.hunk_info().is_some() {
2804                return true;
2805            }
2806            cursor.next();
2807        }
2808        false
2809    }
2810
2811    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2812        let snapshot = self.read(cx);
2813        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2814        for range in ranges {
2815            let range = range.to_point(&snapshot);
2816            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2817            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2818                .min(snapshot.len());
2819            cursor.seek(&start, Bias::Right);
2820            while let Some(item) = cursor.item() {
2821                if *cursor.start() >= end {
2822                    break;
2823                }
2824                if item.hunk_info().is_some() {
2825                    return true;
2826                }
2827                cursor.next();
2828            }
2829        }
2830        false
2831    }
2832
2833    pub fn expand_or_collapse_diff_hunks_inner(
2834        &mut self,
2835        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2836        expand: bool,
2837        cx: &mut Context<Self>,
2838    ) -> Vec<Edit<MultiBufferOffset>> {
2839        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2840            return Vec::new();
2841        }
2842        self.sync_mut(cx);
2843        let mut snapshot = self.snapshot.get_mut();
2844        let mut excerpt_edits = Vec::new();
2845        let mut last_hunk_row = None;
2846        for (range, end_excerpt_id) in ranges {
2847            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2848                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2849                    continue;
2850                }
2851                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2852                    continue;
2853                }
2854                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2855                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2856                let start = snapshot.excerpt_offset_for_anchor(&start);
2857                let end = snapshot.excerpt_offset_for_anchor(&end);
2858                last_hunk_row = Some(diff_hunk.row_range.start);
2859                excerpt_edits.push(text::Edit {
2860                    old: start..end,
2861                    new: start..end,
2862                });
2863            }
2864        }
2865
2866        Self::sync_diff_transforms(
2867            &mut snapshot,
2868            excerpt_edits,
2869            DiffChangeKind::ExpandOrCollapseHunks { expand },
2870        )
2871    }
2872
2873    pub fn expand_or_collapse_diff_hunks(
2874        &mut self,
2875        ranges: Vec<Range<Anchor>>,
2876        expand: bool,
2877        cx: &mut Context<Self>,
2878    ) {
2879        let snapshot = self.snapshot.borrow().clone();
2880        let ranges = ranges.iter().map(move |range| {
2881            let end_excerpt_id = range.end.excerpt_id;
2882            let range = range.to_point(&snapshot);
2883            let mut peek_end = range.end;
2884            if range.end.row < snapshot.max_row().0 {
2885                peek_end = Point::new(range.end.row + 1, 0);
2886            };
2887            (range.start..peek_end, end_excerpt_id)
2888        });
2889        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2890        if !edits.is_empty() {
2891            self.subscriptions.publish(edits);
2892        }
2893        cx.emit(Event::DiffHunksToggled);
2894        cx.emit(Event::Edited {
2895            edited_buffer: None,
2896            is_local: true,
2897        });
2898    }
2899
2900    pub fn resize_excerpt(
2901        &mut self,
2902        id: ExcerptId,
2903        range: Range<text::Anchor>,
2904        cx: &mut Context<Self>,
2905    ) {
2906        self.sync_mut(cx);
2907
2908        let mut snapshot = self.snapshot.get_mut();
2909        let locator = snapshot.excerpt_locator_for_id(id);
2910        let mut new_excerpts = SumTree::default();
2911        let mut cursor = snapshot
2912            .excerpts
2913            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2914        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2915
2916        let prefix = cursor.slice(&Some(locator), Bias::Left);
2917        new_excerpts.append(prefix, ());
2918
2919        let mut excerpt = cursor.item().unwrap().clone();
2920        let old_text_len = excerpt.text_summary.len;
2921
2922        excerpt.range.context.start = range.start;
2923        excerpt.range.context.end = range.end;
2924        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2925
2926        excerpt.text_summary = excerpt
2927            .buffer
2928            .text_summary_for_range(excerpt.range.context.clone());
2929
2930        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2931        let old_start_offset = cursor.start().1;
2932        let new_text_len = excerpt.text_summary.len;
2933        let edit = Edit {
2934            old: old_start_offset..old_start_offset + old_text_len,
2935            new: new_start_offset..new_start_offset + new_text_len,
2936        };
2937
2938        if let Some(last_edit) = edits.last_mut() {
2939            if last_edit.old.end == edit.old.start {
2940                last_edit.old.end = edit.old.end;
2941                last_edit.new.end = edit.new.end;
2942            } else {
2943                edits.push(edit);
2944            }
2945        } else {
2946            edits.push(edit);
2947        }
2948
2949        new_excerpts.push(excerpt, ());
2950
2951        cursor.next();
2952
2953        new_excerpts.append(cursor.suffix(), ());
2954
2955        drop(cursor);
2956        snapshot.excerpts = new_excerpts;
2957
2958        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2959        if !edits.is_empty() {
2960            self.subscriptions.publish(edits);
2961        }
2962        cx.emit(Event::Edited {
2963            edited_buffer: None,
2964            is_local: true,
2965        });
2966        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2967        cx.notify();
2968    }
2969
2970    pub fn expand_excerpts(
2971        &mut self,
2972        ids: impl IntoIterator<Item = ExcerptId>,
2973        line_count: u32,
2974        direction: ExpandExcerptDirection,
2975        cx: &mut Context<Self>,
2976    ) {
2977        if line_count == 0 {
2978            return;
2979        }
2980        self.sync_mut(cx);
2981        if !self.excerpts_by_path.is_empty() {
2982            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2983            return;
2984        }
2985        let mut snapshot = self.snapshot.get_mut();
2986
2987        let ids = ids.into_iter().collect::<Vec<_>>();
2988        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2989        let mut new_excerpts = SumTree::default();
2990        let mut cursor = snapshot
2991            .excerpts
2992            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2993        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2994
2995        for locator in &locators {
2996            let prefix = cursor.slice(&Some(locator), Bias::Left);
2997            new_excerpts.append(prefix, ());
2998
2999            let mut excerpt = cursor.item().unwrap().clone();
3000            let old_text_len = excerpt.text_summary.len;
3001
3002            let up_line_count = if direction.should_expand_up() {
3003                line_count
3004            } else {
3005                0
3006            };
3007
3008            let start_row = excerpt
3009                .range
3010                .context
3011                .start
3012                .to_point(&excerpt.buffer)
3013                .row
3014                .saturating_sub(up_line_count);
3015            let start_point = Point::new(start_row, 0);
3016            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3017
3018            let down_line_count = if direction.should_expand_down() {
3019                line_count
3020            } else {
3021                0
3022            };
3023
3024            let mut end_point = excerpt.buffer.clip_point(
3025                excerpt.range.context.end.to_point(&excerpt.buffer)
3026                    + Point::new(down_line_count, 0),
3027                Bias::Left,
3028            );
3029            end_point.column = excerpt.buffer.line_len(end_point.row);
3030            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3031            excerpt.max_buffer_row = end_point.row;
3032
3033            excerpt.text_summary = excerpt
3034                .buffer
3035                .text_summary_for_range(excerpt.range.context.clone());
3036
3037            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3038            let old_start_offset = cursor.start().1;
3039            let new_text_len = excerpt.text_summary.len;
3040            let edit = Edit {
3041                old: old_start_offset..old_start_offset + old_text_len,
3042                new: new_start_offset..new_start_offset + new_text_len,
3043            };
3044
3045            if let Some(last_edit) = edits.last_mut() {
3046                if last_edit.old.end == edit.old.start {
3047                    last_edit.old.end = edit.old.end;
3048                    last_edit.new.end = edit.new.end;
3049                } else {
3050                    edits.push(edit);
3051                }
3052            } else {
3053                edits.push(edit);
3054            }
3055
3056            new_excerpts.push(excerpt, ());
3057
3058            cursor.next();
3059        }
3060
3061        new_excerpts.append(cursor.suffix(), ());
3062
3063        drop(cursor);
3064        snapshot.excerpts = new_excerpts;
3065
3066        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3067        if !edits.is_empty() {
3068            self.subscriptions.publish(edits);
3069        }
3070        cx.emit(Event::Edited {
3071            edited_buffer: None,
3072            is_local: true,
3073        });
3074        cx.emit(Event::ExcerptsExpanded { ids });
3075        cx.notify();
3076    }
3077
3078    #[ztracing::instrument(skip_all)]
3079    fn sync(&self, cx: &App) {
3080        let changed = self.buffer_changed_since_sync.replace(false);
3081        if !changed {
3082            return;
3083        }
3084        let edits = Self::sync_from_buffer_changes(
3085            &mut self.snapshot.borrow_mut(),
3086            &self.buffers,
3087            &self.diffs,
3088            cx,
3089        );
3090        if !edits.is_empty() {
3091            self.subscriptions.publish(edits);
3092        }
3093    }
3094
3095    fn sync_mut(&mut self, cx: &App) {
3096        let changed = self.buffer_changed_since_sync.replace(false);
3097        if !changed {
3098            return;
3099        }
3100        let edits =
3101            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3102
3103        if !edits.is_empty() {
3104            self.subscriptions.publish(edits);
3105        }
3106    }
3107
3108    fn sync_from_buffer_changes(
3109        snapshot: &mut MultiBufferSnapshot,
3110        buffers: &BTreeMap<BufferId, BufferState>,
3111        diffs: &HashMap<BufferId, DiffState>,
3112        cx: &App,
3113    ) -> Vec<Edit<MultiBufferOffset>> {
3114        let MultiBufferSnapshot {
3115            excerpts,
3116            buffer_locators: _,
3117            diffs: buffer_diff,
3118            diff_transforms: _,
3119            non_text_state_update_count,
3120            edit_count,
3121            is_dirty,
3122            has_deleted_file,
3123            has_conflict,
3124            has_inverted_diff: _,
3125            singleton: _,
3126            excerpt_ids: _,
3127            replaced_excerpts: _,
3128            trailing_excerpt_update_count: _,
3129            all_diff_hunks_expanded: _,
3130            show_deleted_hunks: _,
3131            use_extended_diff_range: _,
3132            show_headers: _,
3133        } = snapshot;
3134        *is_dirty = false;
3135        *has_deleted_file = false;
3136        *has_conflict = false;
3137
3138        if !diffs.is_empty() {
3139            let mut diffs_to_add = Vec::new();
3140            for (id, diff) in diffs {
3141                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3142                // and use the diff hunk base text ranges to compute diff transforms.
3143                // Those base text ranges are usize, so make sure if the base text changed
3144                // we also update the diff snapshot so that we don't use stale offsets
3145                if buffer_diff.get(id).is_none_or(|existing_diff| {
3146                    if existing_diff.main_buffer.is_none() {
3147                        return false;
3148                    }
3149                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3150                    base_text.remote_id() != existing_diff.base_text().remote_id()
3151                        || base_text
3152                            .version()
3153                            .changed_since(existing_diff.base_text().version())
3154                }) {
3155                    if diffs_to_add.capacity() == 0 {
3156                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3157                        // meaning re-allocations will be fairly expensive
3158                        diffs_to_add.reserve(diffs.len());
3159                    }
3160                    diffs_to_add.push((*id, diff.snapshot(cx)));
3161                }
3162            }
3163            buffer_diff.extend(diffs_to_add);
3164        }
3165
3166        let mut excerpts_to_edit = Vec::new();
3167        let mut non_text_state_updated = false;
3168        let mut edited = false;
3169        for buffer_state in buffers.values() {
3170            let buffer = buffer_state.buffer.read(cx);
3171            let version = buffer.version();
3172            let non_text_state_update_count = buffer.non_text_state_update_count();
3173
3174            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3175            let buffer_non_text_state_updated =
3176                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3177            if buffer_edited || buffer_non_text_state_updated {
3178                *buffer_state.last_version.borrow_mut() = version;
3179                buffer_state
3180                    .last_non_text_state_update_count
3181                    .set(non_text_state_update_count);
3182                excerpts_to_edit.extend(
3183                    buffer_state
3184                        .excerpts
3185                        .iter()
3186                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3187                );
3188            }
3189
3190            edited |= buffer_edited;
3191            non_text_state_updated |= buffer_non_text_state_updated;
3192            *is_dirty |= buffer.is_dirty();
3193            *has_deleted_file |= buffer
3194                .file()
3195                .is_some_and(|file| file.disk_state().is_deleted());
3196            *has_conflict |= buffer.has_conflict();
3197        }
3198        if edited {
3199            *edit_count += 1;
3200        }
3201        if non_text_state_updated {
3202            *non_text_state_update_count += 1;
3203        }
3204
3205        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3206
3207        let mut edits = Vec::new();
3208        let mut new_excerpts = SumTree::default();
3209        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3210
3211        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3212            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3213            let old_excerpt = cursor.item().unwrap();
3214            let buffer = buffer.read(cx);
3215            let buffer_id = buffer.remote_id();
3216            let mut new_excerpt;
3217            if buffer_edited {
3218                edits.extend(
3219                    buffer
3220                        .edits_since_in_range::<usize>(
3221                            old_excerpt.buffer.version(),
3222                            old_excerpt.range.context.clone(),
3223                        )
3224                        .map(|edit| {
3225                            let excerpt_old_start = cursor.start().1;
3226                            let excerpt_new_start =
3227                                ExcerptDimension(new_excerpts.summary().text.len);
3228                            let old_start = excerpt_old_start + edit.old.start;
3229                            let old_end = excerpt_old_start + edit.old.end;
3230                            let new_start = excerpt_new_start + edit.new.start;
3231                            let new_end = excerpt_new_start + edit.new.end;
3232                            Edit {
3233                                old: old_start..old_end,
3234                                new: new_start..new_end,
3235                            }
3236                        }),
3237                );
3238
3239                new_excerpt = Excerpt::new(
3240                    old_excerpt.id,
3241                    locator.clone(),
3242                    buffer_id,
3243                    Arc::new(buffer.snapshot()),
3244                    old_excerpt.range.clone(),
3245                    old_excerpt.has_trailing_newline,
3246                );
3247            } else {
3248                new_excerpt = old_excerpt.clone();
3249                new_excerpt.buffer = Arc::new(buffer.snapshot());
3250            }
3251
3252            new_excerpts.push(new_excerpt, ());
3253            cursor.next();
3254        }
3255        new_excerpts.append(cursor.suffix(), ());
3256
3257        drop(cursor);
3258        *excerpts = new_excerpts;
3259
3260        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3261    }
3262
3263    fn sync_diff_transforms(
3264        snapshot: &mut MultiBufferSnapshot,
3265        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3266        change_kind: DiffChangeKind,
3267    ) -> Vec<Edit<MultiBufferOffset>> {
3268        if excerpt_edits.is_empty() {
3269            return vec![];
3270        }
3271
3272        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3273        let mut old_diff_transforms = snapshot
3274            .diff_transforms
3275            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3276        let mut new_diff_transforms = SumTree::default();
3277        let mut old_expanded_hunks = HashSet::default();
3278        let mut output_edits = Vec::new();
3279        let mut output_delta = 0_isize;
3280        let mut at_transform_boundary = true;
3281        let mut end_of_current_insert = None;
3282
3283        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3284        while let Some(edit) = excerpt_edits.next() {
3285            excerpts.seek_forward(&edit.new.start, Bias::Right);
3286            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3287                excerpts.prev();
3288            }
3289
3290            // Keep any transforms that are before the edit.
3291            if at_transform_boundary {
3292                at_transform_boundary = false;
3293                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3294                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3295                if let Some(transform) = old_diff_transforms.item()
3296                    && old_diff_transforms.end().0 == edit.old.start
3297                    && old_diff_transforms.start().0 < edit.old.start
3298                {
3299                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3300                    old_diff_transforms.next();
3301                }
3302            }
3303
3304            // Compute the start of the edit in output coordinates.
3305            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3306            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3307            let edit_new_start =
3308                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3309
3310            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3311                &edit,
3312                &mut excerpts,
3313                &mut old_diff_transforms,
3314                &mut new_diff_transforms,
3315                &mut end_of_current_insert,
3316                &mut old_expanded_hunks,
3317                snapshot,
3318                change_kind,
3319            );
3320
3321            // Compute the end of the edit in output coordinates.
3322            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3323            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3324            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3325            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3326            let output_edit = Edit {
3327                old: edit_old_start..edit_old_end,
3328                new: edit_new_start..edit_new_end,
3329            };
3330
3331            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3332            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3333            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3334                output_edits.push(output_edit);
3335            }
3336
3337            // If this is the last edit that intersects the current diff transform,
3338            // then recreate the content up to the end of this transform, to prepare
3339            // for reusing additional slices of the old transforms.
3340            if excerpt_edits
3341                .peek()
3342                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3343            {
3344                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3345                    && match old_diff_transforms.item() {
3346                        Some(DiffTransform::BufferContent {
3347                            inserted_hunk_info: Some(hunk),
3348                            ..
3349                        }) => excerpts.item().is_some_and(|excerpt| {
3350                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3351                                && diff.main_buffer.is_some()
3352                            {
3353                                return true;
3354                            }
3355                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3356                        }),
3357                        _ => true,
3358                    };
3359
3360                let mut excerpt_offset = edit.new.end;
3361                if !keep_next_old_transform {
3362                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3363                    old_diff_transforms.next();
3364                }
3365
3366                old_expanded_hunks.clear();
3367                Self::push_buffer_content_transform(
3368                    snapshot,
3369                    &mut new_diff_transforms,
3370                    excerpt_offset,
3371                    end_of_current_insert,
3372                );
3373                at_transform_boundary = true;
3374            }
3375        }
3376
3377        // Keep any transforms that are after the last edit.
3378        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3379
3380        // Ensure there's always at least one buffer content transform.
3381        if new_diff_transforms.is_empty() {
3382            new_diff_transforms.push(
3383                DiffTransform::BufferContent {
3384                    summary: Default::default(),
3385                    inserted_hunk_info: None,
3386                },
3387                (),
3388            );
3389        }
3390
3391        drop(old_diff_transforms);
3392        drop(excerpts);
3393        snapshot.diff_transforms = new_diff_transforms;
3394        snapshot.edit_count += 1;
3395
3396        #[cfg(any(test, feature = "test-support"))]
3397        snapshot.check_invariants();
3398        output_edits
3399    }
3400
3401    fn recompute_diff_transforms_for_edit(
3402        edit: &Edit<ExcerptOffset>,
3403        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3404        old_diff_transforms: &mut Cursor<
3405            DiffTransform,
3406            Dimensions<ExcerptOffset, MultiBufferOffset>,
3407        >,
3408        new_diff_transforms: &mut SumTree<DiffTransform>,
3409        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3410        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3411        snapshot: &MultiBufferSnapshot,
3412        change_kind: DiffChangeKind,
3413    ) -> bool {
3414        log::trace!(
3415            "recomputing diff transform for edit {:?} => {:?}",
3416            edit.old.start..edit.old.end,
3417            edit.new.start..edit.new.end
3418        );
3419
3420        // Record which hunks were previously expanded.
3421        while let Some(item) = old_diff_transforms.item() {
3422            if let Some(hunk_info) = item.hunk_info() {
3423                log::trace!(
3424                    "previously expanded hunk at {:?}",
3425                    old_diff_transforms.start()
3426                );
3427                old_expanded_hunks.insert(hunk_info);
3428            }
3429            if old_diff_transforms.end().0 > edit.old.end {
3430                break;
3431            }
3432            old_diff_transforms.next();
3433        }
3434
3435        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3436        // For inverted diffs, hunks are always shown, so we can't skip this.
3437        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3438        if old_expanded_hunks.is_empty()
3439            && change_kind == DiffChangeKind::BufferEdited
3440            && !all_diff_hunks_expanded
3441            && !snapshot.has_inverted_diff
3442        {
3443            return false;
3444        }
3445
3446        // Visit each excerpt that intersects the edit.
3447        let mut did_expand_hunks = false;
3448        while let Some(excerpt) = excerpts.item() {
3449            // Recompute the expanded hunks in the portion of the excerpt that
3450            // intersects the edit.
3451            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3452                let buffer = &excerpt.buffer;
3453                let excerpt_start = *excerpts.start();
3454                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3455                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3456                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3457                let edit_buffer_start =
3458                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3459                let edit_buffer_end =
3460                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3461                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3462
3463                if let Some(main_buffer) = &diff.main_buffer {
3464                    for hunk in diff.hunks_intersecting_base_text_range(
3465                        edit_buffer_start..edit_buffer_end,
3466                        main_buffer,
3467                    ) {
3468                        did_expand_hunks = true;
3469                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3470                        if hunk_buffer_range.start < excerpt_buffer_start {
3471                            log::trace!("skipping hunk that starts before excerpt");
3472                            continue;
3473                        }
3474                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3475                        let hunk_excerpt_start = excerpt_start
3476                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3477                        let hunk_excerpt_end = excerpt_end
3478                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3479                        Self::push_buffer_content_transform(
3480                            snapshot,
3481                            new_diff_transforms,
3482                            hunk_excerpt_start,
3483                            *end_of_current_insert,
3484                        );
3485                        if !hunk_buffer_range.is_empty() {
3486                            let hunk_info = DiffTransformHunkInfo {
3487                                excerpt_id: excerpt.id,
3488                                hunk_start_anchor: hunk.buffer_range.start,
3489                                hunk_secondary_status: hunk.secondary_status,
3490                                is_logically_deleted: true,
3491                            };
3492                            *end_of_current_insert =
3493                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3494                        }
3495                    }
3496                } else {
3497                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3498                        ..buffer.anchor_after(edit_buffer_end);
3499                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3500                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3501                            continue;
3502                        }
3503
3504                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3505                        if hunk_buffer_range.start < excerpt_buffer_start {
3506                            log::trace!("skipping hunk that starts before excerpt");
3507                            continue;
3508                        }
3509
3510                        let hunk_info = DiffTransformHunkInfo {
3511                            excerpt_id: excerpt.id,
3512                            hunk_start_anchor: hunk.buffer_range.start,
3513                            hunk_secondary_status: hunk.secondary_status,
3514                            is_logically_deleted: false,
3515                        };
3516
3517                        let hunk_excerpt_start = excerpt_start
3518                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3519                        let hunk_excerpt_end = excerpt_end
3520                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3521
3522                        Self::push_buffer_content_transform(
3523                            snapshot,
3524                            new_diff_transforms,
3525                            hunk_excerpt_start,
3526                            *end_of_current_insert,
3527                        );
3528
3529                        // For every existing hunk, determine if it was previously expanded
3530                        // and if it should currently be expanded.
3531                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3532                        let should_expand_hunk = match &change_kind {
3533                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3534                                was_previously_expanded || all_diff_hunks_expanded
3535                            }
3536                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3537                                let intersects = hunk_buffer_range.is_empty()
3538                                    || hunk_buffer_range.end > edit_buffer_start;
3539                                if *expand {
3540                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3541                                } else {
3542                                    !intersects
3543                                        && (was_previously_expanded || all_diff_hunks_expanded)
3544                                }
3545                            }
3546                            _ => was_previously_expanded || all_diff_hunks_expanded,
3547                        };
3548
3549                        if should_expand_hunk {
3550                            did_expand_hunks = true;
3551                            log::trace!(
3552                                "expanding hunk {:?}, excerpt:{:?}",
3553                                hunk_excerpt_start..hunk_excerpt_end,
3554                                excerpt.id
3555                            );
3556
3557                            if !hunk.diff_base_byte_range.is_empty()
3558                                && hunk_buffer_range.start >= edit_buffer_start
3559                                && hunk_buffer_range.start <= excerpt_buffer_end
3560                                && snapshot.show_deleted_hunks
3561                            {
3562                                let base_text = diff.base_text();
3563                                let mut text_cursor =
3564                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3565                                let mut base_text_summary = text_cursor
3566                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3567
3568                                let mut has_trailing_newline = false;
3569                                if base_text_summary.last_line_chars > 0 {
3570                                    base_text_summary += TextSummary::newline();
3571                                    has_trailing_newline = true;
3572                                }
3573
3574                                new_diff_transforms.push(
3575                                    DiffTransform::DeletedHunk {
3576                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3577                                        summary: base_text_summary,
3578                                        buffer_id: excerpt.buffer_id,
3579                                        hunk_info,
3580                                        has_trailing_newline,
3581                                    },
3582                                    (),
3583                                );
3584                            }
3585
3586                            if !hunk_buffer_range.is_empty() {
3587                                *end_of_current_insert =
3588                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3589                            }
3590                        }
3591                    }
3592                }
3593            }
3594
3595            if excerpts.end() <= edit.new.end {
3596                excerpts.next();
3597            } else {
3598                break;
3599            }
3600        }
3601
3602        did_expand_hunks || !old_expanded_hunks.is_empty()
3603    }
3604
3605    fn append_diff_transforms(
3606        new_transforms: &mut SumTree<DiffTransform>,
3607        subtree: SumTree<DiffTransform>,
3608    ) {
3609        if let Some(DiffTransform::BufferContent {
3610            inserted_hunk_info,
3611            summary,
3612        }) = subtree.first()
3613            && Self::extend_last_buffer_content_transform(
3614                new_transforms,
3615                *inserted_hunk_info,
3616                *summary,
3617            )
3618        {
3619            let mut cursor = subtree.cursor::<()>(());
3620            cursor.next();
3621            cursor.next();
3622            new_transforms.append(cursor.suffix(), ());
3623            return;
3624        }
3625        new_transforms.append(subtree, ());
3626    }
3627
3628    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3629        if let DiffTransform::BufferContent {
3630            inserted_hunk_info: inserted_hunk_anchor,
3631            summary,
3632        } = transform
3633            && Self::extend_last_buffer_content_transform(
3634                new_transforms,
3635                inserted_hunk_anchor,
3636                summary,
3637            )
3638        {
3639            return;
3640        }
3641        new_transforms.push(transform, ());
3642    }
3643
3644    fn push_buffer_content_transform(
3645        old_snapshot: &MultiBufferSnapshot,
3646        new_transforms: &mut SumTree<DiffTransform>,
3647        end_offset: ExcerptOffset,
3648        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3649    ) {
3650        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3651            (end_offset.min(insertion_end_offset), Some(hunk_info))
3652        });
3653        let unchanged_region = [(end_offset, None)];
3654
3655        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3656        {
3657            let start_offset = new_transforms.summary().excerpt_len();
3658            if end_offset <= start_offset {
3659                continue;
3660            }
3661            let summary_to_add = old_snapshot
3662                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3663
3664            if !Self::extend_last_buffer_content_transform(
3665                new_transforms,
3666                inserted_hunk_info,
3667                summary_to_add,
3668            ) {
3669                new_transforms.push(
3670                    DiffTransform::BufferContent {
3671                        summary: summary_to_add,
3672                        inserted_hunk_info,
3673                    },
3674                    (),
3675                )
3676            }
3677        }
3678    }
3679
3680    fn extend_last_buffer_content_transform(
3681        new_transforms: &mut SumTree<DiffTransform>,
3682        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3683        summary_to_add: MBTextSummary,
3684    ) -> bool {
3685        let mut did_extend = false;
3686        new_transforms.update_last(
3687            |last_transform| {
3688                if let DiffTransform::BufferContent {
3689                    summary,
3690                    inserted_hunk_info: inserted_hunk_anchor,
3691                } = last_transform
3692                    && *inserted_hunk_anchor == new_inserted_hunk_info
3693                {
3694                    *summary += summary_to_add;
3695                    did_extend = true;
3696                }
3697            },
3698            (),
3699        );
3700        did_extend
3701    }
3702
3703    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3704        let snapshot = self.snapshot(cx);
3705        let excerpt_id = range.end.excerpt_id;
3706        let point_range = range.to_point(&snapshot);
3707        let expand = !self.single_hunk_is_expanded(range, cx);
3708        let edits =
3709            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3710        if !edits.is_empty() {
3711            self.subscriptions.publish(edits);
3712        }
3713        cx.emit(Event::DiffHunksToggled);
3714        cx.emit(Event::Edited {
3715            edited_buffer: None,
3716            is_local: true,
3717        });
3718    }
3719}
3720
3721fn build_excerpt_ranges(
3722    ranges: impl IntoIterator<Item = Range<Point>>,
3723    context_line_count: u32,
3724    buffer_snapshot: &BufferSnapshot,
3725) -> Vec<ExcerptRange<Point>> {
3726    ranges
3727        .into_iter()
3728        .map(|range| {
3729            let start_row = range.start.row.saturating_sub(context_line_count);
3730            let start = Point::new(start_row, 0);
3731            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3732            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3733            ExcerptRange {
3734                context: start..end,
3735                primary: range,
3736            }
3737        })
3738        .collect()
3739}
3740
3741#[cfg(any(test, feature = "test-support"))]
3742impl MultiBuffer {
3743    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3744        let buffer = cx.new(|cx| Buffer::local(text, cx));
3745        cx.new(|cx| Self::singleton(buffer, cx))
3746    }
3747
3748    pub fn build_multi<const COUNT: usize>(
3749        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3750        cx: &mut gpui::App,
3751    ) -> Entity<Self> {
3752        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3753        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3754            let buffer = cx.new(|cx| Buffer::local(text, cx));
3755            let snapshot = buffer.read(cx).snapshot();
3756            let excerpt_ranges = ranges
3757                .into_iter()
3758                .map(ExcerptRange::new)
3759                .collect::<Vec<_>>();
3760            multi.update(cx, |multi, cx| {
3761                multi.set_excerpt_ranges_for_path(
3762                    PathKey::sorted(ix as u64),
3763                    buffer,
3764                    &snapshot,
3765                    excerpt_ranges,
3766                    cx,
3767                )
3768            });
3769        }
3770
3771        multi
3772    }
3773
3774    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3775        cx.new(|cx| Self::singleton(buffer, cx))
3776    }
3777
3778    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3779        cx.new(|cx| {
3780            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3781            let mutation_count = rng.random_range(1..=5);
3782            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3783            multibuffer
3784        })
3785    }
3786
3787    pub fn randomly_edit(
3788        &mut self,
3789        rng: &mut impl rand::Rng,
3790        edit_count: usize,
3791        cx: &mut Context<Self>,
3792    ) {
3793        use util::RandomCharIter;
3794
3795        let snapshot = self.read(cx);
3796        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3797        let mut last_end = None;
3798        for _ in 0..edit_count {
3799            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3800                break;
3801            }
3802
3803            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3804            let end =
3805                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3806            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3807            last_end = Some(end);
3808
3809            let mut range = start..end;
3810            if rng.random_bool(0.2) {
3811                mem::swap(&mut range.start, &mut range.end);
3812            }
3813
3814            let new_text_len = rng.random_range(0..10);
3815            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3816
3817            edits.push((range, new_text.into()));
3818        }
3819        log::info!("mutating multi-buffer with {:?}", edits);
3820        drop(snapshot);
3821
3822        self.edit(edits, None, cx);
3823    }
3824
3825    pub fn randomly_edit_excerpts(
3826        &mut self,
3827        rng: &mut impl rand::Rng,
3828        mutation_count: usize,
3829        cx: &mut Context<Self>,
3830    ) {
3831        use rand::prelude::*;
3832        use std::env;
3833        use util::RandomCharIter;
3834
3835        let max_excerpts = env::var("MAX_EXCERPTS")
3836            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3837            .unwrap_or(5);
3838
3839        let mut buffers = Vec::new();
3840        for _ in 0..mutation_count {
3841            if rng.random_bool(0.05) {
3842                log::info!("Clearing multi-buffer");
3843                self.clear(cx);
3844                continue;
3845            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3846                let ids = self.excerpt_ids();
3847                let mut excerpts = HashSet::default();
3848                for _ in 0..rng.random_range(0..ids.len()) {
3849                    excerpts.extend(ids.choose(rng).copied());
3850                }
3851
3852                let line_count = rng.random_range(0..5);
3853
3854                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3855
3856                self.expand_excerpts(
3857                    excerpts.iter().cloned(),
3858                    line_count,
3859                    ExpandExcerptDirection::UpAndDown,
3860                    cx,
3861                );
3862                continue;
3863            }
3864
3865            let excerpt_ids = self.excerpt_ids();
3866            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3867                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3868                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3869                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3870                    let buffer = buffers.last().unwrap().read(cx);
3871                    log::info!(
3872                        "Creating new buffer {} with text: {:?}",
3873                        buffer.remote_id(),
3874                        buffer.text()
3875                    );
3876                    buffers.last().unwrap().clone()
3877                } else {
3878                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3879                };
3880
3881                let buffer = buffer_handle.read(cx);
3882                let buffer_text = buffer.text();
3883                let ranges = (0..rng.random_range(0..5))
3884                    .map(|_| {
3885                        let end_ix =
3886                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3887                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3888                        ExcerptRange::new(start_ix..end_ix)
3889                    })
3890                    .collect::<Vec<_>>();
3891                log::info!(
3892                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3893                    buffer_handle.read(cx).remote_id(),
3894                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3895                    ranges
3896                        .iter()
3897                        .map(|r| &buffer_text[r.context.clone()])
3898                        .collect::<Vec<_>>()
3899                );
3900
3901                let excerpt_id =
3902                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3903                log::info!("Inserted with ids: {:?}", excerpt_id);
3904            } else {
3905                let remove_count = rng.random_range(1..=excerpt_ids.len());
3906                let mut excerpts_to_remove = excerpt_ids
3907                    .choose_multiple(rng, remove_count)
3908                    .cloned()
3909                    .collect::<Vec<_>>();
3910                let snapshot = self.snapshot.borrow();
3911                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3912                drop(snapshot);
3913                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3914                self.remove_excerpts(excerpts_to_remove, cx);
3915            }
3916        }
3917    }
3918
3919    pub fn randomly_mutate(
3920        &mut self,
3921        rng: &mut impl rand::Rng,
3922        mutation_count: usize,
3923        cx: &mut Context<Self>,
3924    ) {
3925        use rand::prelude::*;
3926
3927        if rng.random_bool(0.7) || self.singleton {
3928            let buffer = self
3929                .buffers
3930                .values()
3931                .choose(rng)
3932                .map(|state| state.buffer.clone());
3933
3934            if let Some(buffer) = buffer {
3935                buffer.update(cx, |buffer, cx| {
3936                    if rng.random() {
3937                        buffer.randomly_edit(rng, mutation_count, cx);
3938                    } else {
3939                        buffer.randomly_undo_redo(rng, cx);
3940                    }
3941                });
3942            } else {
3943                self.randomly_edit(rng, mutation_count, cx);
3944            }
3945        } else {
3946            self.randomly_edit_excerpts(rng, mutation_count, cx);
3947        }
3948
3949        self.check_invariants(cx);
3950    }
3951
3952    fn check_invariants(&self, cx: &App) {
3953        self.read(cx).check_invariants();
3954    }
3955}
3956
3957impl EventEmitter<Event> for MultiBuffer {}
3958
3959impl MultiBufferSnapshot {
3960    pub fn text(&self) -> String {
3961        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3962            .map(|chunk| chunk.text)
3963            .collect()
3964    }
3965
3966    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3967        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3968            .flat_map(|c| c.chars().rev())
3969    }
3970
3971    fn reversed_chunks_in_range(
3972        &self,
3973        range: Range<MultiBufferOffset>,
3974    ) -> ReversedMultiBufferChunks<'_> {
3975        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3976        cursor.seek(&range.end);
3977        let current_chunks = cursor.region().as_ref().map(|region| {
3978            let start_overshoot = range.start.saturating_sub(region.range.start);
3979            let end_overshoot = range.end - region.range.start;
3980            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3981            let start = region.buffer_range.start + start_overshoot;
3982            region.buffer.reversed_chunks_in_range(start..end)
3983        });
3984        ReversedMultiBufferChunks {
3985            cursor,
3986            current_chunks,
3987            start: range.start,
3988            offset: range.end,
3989        }
3990    }
3991
3992    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3993        let offset = position.to_offset(self);
3994        self.text_for_range(offset..self.len())
3995            .flat_map(|chunk| chunk.chars())
3996    }
3997
3998    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3999        self.chunks(range, false).map(|chunk| chunk.text)
4000    }
4001
4002    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
4003        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
4004            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
4005    }
4006
4007    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
4008    where
4009        T: ToOffset,
4010    {
4011        let position = position.to_offset(self);
4012        position == self.clip_offset(position, Bias::Left)
4013            && self
4014                .bytes_in_range(position..self.len())
4015                .flatten()
4016                .copied()
4017                .take(needle.len())
4018                .eq(needle.bytes())
4019    }
4020
4021    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4022        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4023    }
4024
4025    pub fn diff_hunks_in_range<T: ToPoint>(
4026        &self,
4027        range: Range<T>,
4028    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4029        let query_range = range.start.to_point(self)..range.end.to_point(self);
4030        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4031            let diff = self.diffs.get(&buffer.remote_id())?;
4032            let iter = if let Some(main_buffer) = &diff.main_buffer {
4033                let buffer_start = buffer.point_to_offset(buffer_range.start);
4034                let buffer_end = buffer.point_to_offset(buffer_range.end);
4035                itertools::Either::Left(
4036                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4037                        .map(move |hunk| (hunk, buffer, true)),
4038                )
4039            } else {
4040                let buffer_start = buffer.anchor_before(buffer_range.start);
4041                let buffer_end = buffer.anchor_after(buffer_range.end);
4042                itertools::Either::Right(
4043                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4044                        .map(move |hunk| (hunk, buffer, false)),
4045                )
4046            };
4047            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4048                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4049                    return None;
4050                }
4051                let range = if is_inverted {
4052                    hunk.diff_base_byte_range.to_point(&buffer)
4053                } else {
4054                    hunk.range.clone()
4055                };
4056                Some((range, (hunk, is_inverted)))
4057            }))
4058        })
4059        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4060            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4061            {
4062                return None;
4063            }
4064            let end_row = if range.end.column == 0 {
4065                range.end.row
4066            } else {
4067                range.end.row + 1
4068            };
4069
4070            let word_diffs =
4071                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4072                    .then(|| {
4073                        let mut word_diffs = Vec::new();
4074
4075                        if self.show_deleted_hunks || is_inverted {
4076                            let hunk_start_offset = if is_inverted {
4077                                Anchor::in_buffer(
4078                                    excerpt.id,
4079                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4080                                )
4081                                .to_offset(self)
4082                            } else {
4083                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4084                                    .to_offset(self)
4085                            };
4086
4087                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4088                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4089                            }));
4090                        }
4091
4092                        if !is_inverted {
4093                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4094                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4095                            }));
4096                        }
4097                        word_diffs
4098                    })
4099                    .unwrap_or_default();
4100
4101            let buffer_range = if is_inverted {
4102                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4103                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4104            } else {
4105                hunk.buffer_range.clone()
4106            };
4107            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4108                DiffHunkStatusKind::Deleted
4109            } else if hunk.diff_base_byte_range.is_empty() {
4110                DiffHunkStatusKind::Added
4111            } else {
4112                DiffHunkStatusKind::Modified
4113            };
4114            Some(MultiBufferDiffHunk {
4115                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4116                buffer_id: excerpt.buffer_id,
4117                excerpt_id: excerpt.id,
4118                buffer_range,
4119                word_diffs,
4120                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4121                    ..BufferOffset(hunk.diff_base_byte_range.end),
4122                status: DiffHunkStatus {
4123                    kind: status_kind,
4124                    secondary: hunk.secondary_status,
4125                },
4126            })
4127        })
4128    }
4129
4130    fn excerpts_for_range<T: ToOffset>(
4131        &self,
4132        range: Range<T>,
4133    ) -> impl Iterator<Item = &Excerpt> + '_ {
4134        let range = range.start.to_offset(self)..range.end.to_offset(self);
4135        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4136        cursor.seek(&range.start);
4137        std::iter::from_fn(move || {
4138            let region = cursor.region()?;
4139            if region.range.start > range.end
4140                || region.range.start == range.end && region.range.start > range.start
4141            {
4142                return None;
4143            }
4144            let excerpt = region.excerpt;
4145            cursor.next_excerpt_forwards();
4146            Some(excerpt)
4147        })
4148    }
4149
4150    pub fn excerpt_ids_for_range<T: ToOffset>(
4151        &self,
4152        range: Range<T>,
4153    ) -> impl Iterator<Item = ExcerptId> + '_ {
4154        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4155    }
4156
4157    pub fn buffer_ids_for_range<T: ToOffset>(
4158        &self,
4159        range: Range<T>,
4160    ) -> impl Iterator<Item = BufferId> + '_ {
4161        self.excerpts_for_range(range)
4162            .map(|excerpt| excerpt.buffer_id)
4163    }
4164
4165    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4166    ///
4167    /// The passed in anchors must be ordered.
4168    pub fn text_anchors_to_visible_anchors(
4169        &self,
4170        anchors: impl IntoIterator<Item = text::Anchor>,
4171    ) -> Vec<Option<Anchor>> {
4172        let anchors = anchors.into_iter();
4173        let mut result = Vec::with_capacity(anchors.size_hint().0);
4174        let mut anchors = anchors.peekable();
4175        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4176        'anchors: while let Some(anchor) = anchors.peek() {
4177            let Some(buffer_id) = anchor.buffer_id else {
4178                anchors.next();
4179                result.push(None);
4180                continue 'anchors;
4181            };
4182            let mut same_buffer_anchors =
4183                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4184
4185            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4186                let Some(mut next) = same_buffer_anchors.next() else {
4187                    continue 'anchors;
4188                };
4189                'excerpts: for locator in locators.iter() {
4190                    if cursor.seek_forward(&Some(locator), Bias::Left)
4191                        && let Some(excerpt) = cursor.item()
4192                    {
4193                        loop {
4194                            // anchor is before the first excerpt
4195                            if excerpt
4196                                .range
4197                                .context
4198                                .start
4199                                .cmp(&next, &excerpt.buffer)
4200                                .is_gt()
4201                            {
4202                                // so we skip it and try the next anchor
4203                                result.push(None);
4204                                match same_buffer_anchors.next() {
4205                                    Some(anchor) => next = anchor,
4206                                    None => continue 'anchors,
4207                                }
4208                            // anchor is within the excerpt
4209                            } else if excerpt
4210                                .range
4211                                .context
4212                                .end
4213                                .cmp(&next, &excerpt.buffer)
4214                                .is_ge()
4215                            {
4216                                // record it and all following anchors that are within
4217                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4218                                result.extend(
4219                                    same_buffer_anchors
4220                                        .peeking_take_while(|a| {
4221                                            excerpt
4222                                                .range
4223                                                .context
4224                                                .end
4225                                                .cmp(a, &excerpt.buffer)
4226                                                .is_ge()
4227                                        })
4228                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4229                                );
4230                                match same_buffer_anchors.next() {
4231                                    Some(anchor) => next = anchor,
4232                                    None => continue 'anchors,
4233                                }
4234                            // anchor is after the excerpt, try the next one
4235                            } else {
4236                                continue 'excerpts;
4237                            }
4238                        }
4239                    }
4240                }
4241                // account for `next`
4242                result.push(None);
4243            }
4244            result.extend(same_buffer_anchors.map(|_| None));
4245        }
4246
4247        result
4248    }
4249
4250    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4251        &self,
4252        ranges: impl Iterator<Item = Range<T>>,
4253    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4254        ranges.flat_map(|range| {
4255            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4256                .into_iter()
4257        })
4258    }
4259
4260    pub fn range_to_buffer_ranges<R, T>(
4261        &self,
4262        range: R,
4263    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4264    where
4265        R: RangeBounds<T>,
4266        T: ToOffset,
4267    {
4268        self.range_to_buffer_ranges_with_context(range)
4269            .into_iter()
4270            .map(|(buffer, range, id, _context)| (buffer, range, id))
4271            .collect()
4272    }
4273
4274    pub fn range_to_buffer_ranges_with_context<R, T>(
4275        &self,
4276        range: R,
4277    ) -> Vec<(
4278        &BufferSnapshot,
4279        Range<BufferOffset>,
4280        ExcerptId,
4281        Range<text::Anchor>,
4282    )>
4283    where
4284        R: RangeBounds<T>,
4285        T: ToOffset,
4286    {
4287        let start = match range.start_bound() {
4288            Bound::Included(start) => start.to_offset(self),
4289            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4290            Bound::Unbounded => MultiBufferOffset::ZERO,
4291        };
4292        let end_bound = match range.end_bound() {
4293            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4294            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4295            Bound::Unbounded => Bound::Unbounded,
4296        };
4297        let bounds = (Bound::Included(start), end_bound);
4298
4299        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4300        cursor.seek(&start);
4301
4302        let mut result: Vec<(
4303            &BufferSnapshot,
4304            Range<BufferOffset>,
4305            ExcerptId,
4306            Range<text::Anchor>,
4307        )> = Vec::new();
4308        while let Some(region) = cursor.region() {
4309            let dominated_by_end_bound = match end_bound {
4310                Bound::Included(end) => region.range.start > end,
4311                Bound::Excluded(end) => region.range.start >= end,
4312                Bound::Unbounded => false,
4313            };
4314            if dominated_by_end_bound {
4315                break;
4316            }
4317            if region.is_main_buffer {
4318                let start_overshoot = start.saturating_sub(region.range.start);
4319                let end_offset = match end_bound {
4320                    Bound::Included(end) | Bound::Excluded(end) => end,
4321                    Bound::Unbounded => region.range.end,
4322                };
4323                let end_overshoot = end_offset.saturating_sub(region.range.start);
4324                let start = region
4325                    .buffer_range
4326                    .end
4327                    .min(region.buffer_range.start + start_overshoot);
4328                let end = region
4329                    .buffer_range
4330                    .end
4331                    .min(region.buffer_range.start + end_overshoot);
4332                let context = region.excerpt.range.context.clone();
4333                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4334                    *excerpt_id == region.excerpt.id && prev_range.end == start
4335                }) {
4336                    prev.1.end = end;
4337                } else {
4338                    result.push((region.buffer, start..end, region.excerpt.id, context));
4339                }
4340            }
4341            cursor.next();
4342        }
4343
4344        if let Some(excerpt) = cursor.excerpt() {
4345            let dominated_by_prev_excerpt =
4346                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4347            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4348                let excerpt_position = self.len();
4349                if bounds.contains(&excerpt_position) {
4350                    let buffer_offset =
4351                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4352                    let context = excerpt.range.context.clone();
4353                    result.push((
4354                        &excerpt.buffer,
4355                        buffer_offset..buffer_offset,
4356                        excerpt.id,
4357                        context,
4358                    ));
4359                }
4360            }
4361        }
4362
4363        result
4364    }
4365
4366    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4367        &self,
4368        range: Range<T>,
4369    ) -> impl Iterator<
4370        Item = (
4371            &BufferSnapshot,
4372            Range<BufferOffset>,
4373            ExcerptId,
4374            Option<Anchor>,
4375        ),
4376    > + '_ {
4377        let start = range.start.to_offset(self);
4378        let end = range.end.to_offset(self);
4379
4380        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4381        cursor.seek(&start);
4382
4383        std::iter::from_fn(move || {
4384            let region = cursor.region()?;
4385            if region.range.start > end {
4386                return None;
4387            }
4388            let start_overshoot = start.saturating_sub(region.range.start);
4389            let end_overshoot = end.saturating_sub(region.range.start);
4390            let start = region
4391                .buffer_range
4392                .end
4393                .min(region.buffer_range.start + start_overshoot);
4394            let end = region
4395                .buffer_range
4396                .end
4397                .min(region.buffer_range.start + end_overshoot);
4398
4399            let region_excerpt_id = region.excerpt.id;
4400            let deleted_hunk_anchor = if region.is_main_buffer {
4401                None
4402            } else {
4403                Some(self.anchor_before(region.range.start))
4404            };
4405            let result = (
4406                region.buffer,
4407                start..end,
4408                region_excerpt_id,
4409                deleted_hunk_anchor,
4410            );
4411            cursor.next();
4412            Some(result)
4413        })
4414    }
4415
4416    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4417    /// coordinates.
4418    ///
4419    /// The given callback will be called for every excerpt intersecting the given range. It will
4420    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4421    /// The callback should return an iterator of metadata items from that buffer, each paired
4422    /// with a buffer range.
4423    ///
4424    /// The returned iterator yields each of these metadata items, paired with its range in
4425    /// multi-buffer coordinates.
4426    fn lift_buffer_metadata<'a, MBD, M, I>(
4427        &'a self,
4428        query_range: Range<MBD>,
4429        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4430    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4431    where
4432        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4433        MBD: MultiBufferDimension
4434            + Ord
4435            + Sub<Output = MBD::TextDimension>
4436            + ops::Add<MBD::TextDimension, Output = MBD>
4437            + ops::AddAssign<MBD::TextDimension>,
4438        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4439            + ops::Add<Output = MBD::TextDimension>
4440            + AddAssign<MBD::TextDimension>
4441            + Ord,
4442    {
4443        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4444        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4445
4446        // Find the excerpt and buffer offset where the given range ends.
4447        cursor.seek(&query_range.end);
4448        let mut range_end = None;
4449        while let Some(region) = cursor.region() {
4450            if region.is_main_buffer {
4451                let mut buffer_end = region.buffer_range.start;
4452                let overshoot = if query_range.end > region.range.start {
4453                    query_range.end - region.range.start
4454                } else {
4455                    <MBD::TextDimension>::default()
4456                };
4457                buffer_end = buffer_end + overshoot;
4458                range_end = Some((region.excerpt.id, buffer_end));
4459                break;
4460            }
4461            cursor.next();
4462        }
4463
4464        cursor.seek(&query_range.start);
4465
4466        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4467            && region.range.start > MBD::default()
4468        {
4469            cursor.prev()
4470        } else if let Some(region) = cursor.region()
4471            && region.is_main_buffer
4472            && region.diff_hunk_status.is_some()
4473        {
4474            cursor.prev();
4475            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4476                cursor.next();
4477            }
4478        }
4479
4480        iter::from_fn(move || {
4481            loop {
4482                let excerpt = cursor.excerpt()?;
4483
4484                // If we have already retrieved metadata for this excerpt, continue to use it.
4485                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4486                    .as_mut()
4487                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4488                {
4489                    Some(metadata)
4490                }
4491                // Otherwise, compute the intersection of the input range with the excerpt's range,
4492                // and retrieve the metadata for the resulting range.
4493                else {
4494                    let region = cursor.region()?;
4495                    let mut buffer_start;
4496                    if region.is_main_buffer {
4497                        buffer_start = region.buffer_range.start;
4498                        if query_range.start > region.range.start {
4499                            let overshoot = query_range.start - region.range.start;
4500                            buffer_start = buffer_start + overshoot;
4501                        }
4502                        buffer_start = buffer_start.min(region.buffer_range.end);
4503                    } else {
4504                        buffer_start = cursor.main_buffer_position()?;
4505                    };
4506                    let mut buffer_end = excerpt
4507                        .range
4508                        .context
4509                        .end
4510                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4511                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4512                        && excerpt.id == end_excerpt_id
4513                    {
4514                        buffer_end = buffer_end.min(end_buffer_offset);
4515                    }
4516
4517                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4518                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4519                    })
4520                };
4521
4522                // Visit each metadata item.
4523                if let Some((metadata_buffer_range, metadata)) =
4524                    metadata_iter.and_then(Iterator::next)
4525                {
4526                    // Find the multibuffer regions that contain the start and end of
4527                    // the metadata item's range.
4528                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4529                        while let Some(region) = cursor.region() {
4530                            if (region.is_main_buffer
4531                                && (region.buffer_range.end >= metadata_buffer_range.start
4532                                    || cursor.is_at_end_of_excerpt()))
4533                                || (!region.is_main_buffer
4534                                    && region.buffer_range.start == metadata_buffer_range.start)
4535                            {
4536                                break;
4537                            }
4538                            cursor.next();
4539                        }
4540                    }
4541                    let start_region = cursor.region()?.clone();
4542                    while let Some(region) = cursor.region() {
4543                        if region.is_main_buffer
4544                            && (region.buffer_range.end > metadata_buffer_range.end
4545                                || cursor.is_at_end_of_excerpt())
4546                        {
4547                            break;
4548                        }
4549                        cursor.next();
4550                    }
4551                    let end_region = cursor.region();
4552
4553                    // Convert the metadata item's range into multibuffer coordinates.
4554                    let mut start_position = start_region.range.start;
4555                    let region_buffer_start = start_region.buffer_range.start;
4556                    if start_region.is_main_buffer
4557                        && metadata_buffer_range.start > region_buffer_start
4558                    {
4559                        start_position =
4560                            start_position + (metadata_buffer_range.start - region_buffer_start);
4561                        start_position = start_position.min(start_region.range.end);
4562                    }
4563
4564                    let mut end_position = self.max_position();
4565                    if let Some(end_region) = &end_region {
4566                        end_position = end_region.range.start;
4567                        debug_assert!(end_region.is_main_buffer);
4568                        let region_buffer_start = end_region.buffer_range.start;
4569                        if metadata_buffer_range.end > region_buffer_start {
4570                            end_position =
4571                                end_position + (metadata_buffer_range.end - region_buffer_start);
4572                        }
4573                        end_position = end_position.min(end_region.range.end);
4574                    }
4575
4576                    if start_position <= query_range.end && end_position >= query_range.start {
4577                        return Some((start_position..end_position, metadata, excerpt));
4578                    }
4579                }
4580                // When there are no more metadata items for this excerpt, move to the next excerpt.
4581                else {
4582                    current_excerpt_metadata.take();
4583                    if let Some((end_excerpt_id, _)) = range_end
4584                        && excerpt.id == end_excerpt_id
4585                    {
4586                        return None;
4587                    }
4588                    cursor.next_excerpt_forwards();
4589                }
4590            }
4591        })
4592    }
4593
4594    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4595        let offset = position.to_offset(self);
4596
4597        let mut cursor = self
4598            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4599            );
4600        cursor.seek(&DimensionPair {
4601            key: offset,
4602            value: None,
4603        });
4604        cursor.seek_to_start_of_current_excerpt();
4605        let excerpt = cursor.excerpt()?;
4606
4607        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4608        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4609        let current_position = self
4610            .anchor_before(offset)
4611            .text_anchor
4612            .to_offset(&excerpt.buffer);
4613
4614        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4615            if let Some(main_buffer) = &diff.main_buffer {
4616                for hunk in diff
4617                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4618                {
4619                    if hunk.diff_base_byte_range.end >= current_position {
4620                        continue;
4621                    }
4622                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4623                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4624                    return Some(MultiBufferRow(start.row));
4625                }
4626            } else {
4627                let excerpt_end = excerpt
4628                    .buffer
4629                    .anchor_before(excerpt_end.min(current_position));
4630                for hunk in diff.hunks_intersecting_range_rev(
4631                    excerpt.range.context.start..excerpt_end,
4632                    &excerpt.buffer,
4633                ) {
4634                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4635                    if hunk_end >= current_position {
4636                        continue;
4637                    }
4638                    let start =
4639                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4640                    return Some(MultiBufferRow(start.row));
4641                }
4642            }
4643        }
4644
4645        loop {
4646            cursor.prev_excerpt();
4647            let excerpt = cursor.excerpt()?;
4648
4649            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4650                continue;
4651            };
4652            if let Some(main_buffer) = &diff.main_buffer {
4653                let Some(hunk) = diff
4654                    .hunks_intersecting_base_text_range_rev(
4655                        excerpt.range.context.to_offset(&excerpt.buffer),
4656                        main_buffer,
4657                    )
4658                    .next()
4659                else {
4660                    continue;
4661                };
4662                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4663                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4664                return Some(MultiBufferRow(start.row));
4665            } else {
4666                let Some(hunk) = diff
4667                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4668                    .next()
4669                else {
4670                    continue;
4671                };
4672                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4673                return Some(MultiBufferRow(start.row));
4674            }
4675        }
4676    }
4677
4678    pub fn has_diff_hunks(&self) -> bool {
4679        self.diffs.values().any(|diff| !diff.is_empty())
4680    }
4681
4682    pub fn is_inside_word<T: ToOffset>(
4683        &self,
4684        position: T,
4685        scope_context: Option<CharScopeContext>,
4686    ) -> bool {
4687        let position = position.to_offset(self);
4688        let classifier = self
4689            .char_classifier_at(position)
4690            .scope_context(scope_context);
4691        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4692        let prev_char_kind = self
4693            .reversed_chars_at(position)
4694            .next()
4695            .map(|c| classifier.kind(c));
4696        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4697    }
4698
4699    pub fn surrounding_word<T: ToOffset>(
4700        &self,
4701        start: T,
4702        scope_context: Option<CharScopeContext>,
4703    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4704        let mut start = start.to_offset(self);
4705        let mut end = start;
4706        let mut next_chars = self.chars_at(start).peekable();
4707        let mut prev_chars = self.reversed_chars_at(start).peekable();
4708
4709        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4710
4711        let word_kind = cmp::max(
4712            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4713            next_chars.peek().copied().map(|c| classifier.kind(c)),
4714        );
4715
4716        for ch in prev_chars {
4717            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4718                start -= ch.len_utf8();
4719            } else {
4720                break;
4721            }
4722        }
4723
4724        for ch in next_chars {
4725            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4726                end += ch.len_utf8();
4727            } else {
4728                break;
4729            }
4730        }
4731
4732        (start..end, word_kind)
4733    }
4734
4735    pub fn char_kind_before<T: ToOffset>(
4736        &self,
4737        start: T,
4738        scope_context: Option<CharScopeContext>,
4739    ) -> Option<CharKind> {
4740        let start = start.to_offset(self);
4741        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4742        self.reversed_chars_at(start)
4743            .next()
4744            .map(|ch| classifier.kind(ch))
4745    }
4746
4747    pub fn is_singleton(&self) -> bool {
4748        self.singleton
4749    }
4750
4751    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4752        if self.singleton {
4753            self.excerpts
4754                .iter()
4755                .next()
4756                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4757        } else {
4758            None
4759        }
4760    }
4761
4762    pub fn len(&self) -> MultiBufferOffset {
4763        self.diff_transforms.summary().output.len
4764    }
4765
4766    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4767        MBD::from_summary(&self.text_summary())
4768    }
4769
4770    pub fn is_empty(&self) -> bool {
4771        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4772    }
4773
4774    pub fn widest_line_number(&self) -> u32 {
4775        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4776        self.excerpts.summary().widest_line_number + 1
4777    }
4778
4779    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4780        let range = range.start.to_offset(self)..range.end.to_offset(self);
4781        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4782        excerpts.seek(&range.start);
4783
4784        let mut chunk;
4785        let mut has_trailing_newline;
4786        let excerpt_bytes;
4787        if let Some(region) = excerpts.region() {
4788            let mut bytes = region.buffer.bytes_in_range(
4789                region.buffer_range.start + (range.start - region.range.start)
4790                    ..(region.buffer_range.start + (range.end - region.range.start))
4791                        .min(region.buffer_range.end),
4792            );
4793            chunk = bytes.next().unwrap_or(&[][..]);
4794            excerpt_bytes = Some(bytes);
4795            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4796            if chunk.is_empty() && has_trailing_newline {
4797                chunk = b"\n";
4798                has_trailing_newline = false;
4799            }
4800        } else {
4801            chunk = &[][..];
4802            excerpt_bytes = None;
4803            has_trailing_newline = false;
4804        };
4805
4806        MultiBufferBytes {
4807            range,
4808            cursor: excerpts,
4809            excerpt_bytes,
4810            has_trailing_newline,
4811            chunk,
4812        }
4813    }
4814
4815    pub fn reversed_bytes_in_range<T: ToOffset>(
4816        &self,
4817        range: Range<T>,
4818    ) -> ReversedMultiBufferBytes<'_> {
4819        let range = range.start.to_offset(self)..range.end.to_offset(self);
4820        let mut chunks = self.reversed_chunks_in_range(range.clone());
4821        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4822        ReversedMultiBufferBytes {
4823            range,
4824            chunks,
4825            chunk,
4826        }
4827    }
4828
4829    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4830        let mut cursor = self.cursor::<Point, Point>();
4831        cursor.seek(&Point::new(start_row.0, 0));
4832        let mut result = MultiBufferRows {
4833            point: Point::new(0, 0),
4834            is_empty: self.excerpts.is_empty(),
4835            is_singleton: self.is_singleton(),
4836            cursor,
4837        };
4838        result.seek(start_row);
4839        result
4840    }
4841
4842    pub fn chunks<T: ToOffset>(
4843        &self,
4844        range: Range<T>,
4845        language_aware: bool,
4846    ) -> MultiBufferChunks<'_> {
4847        let mut chunks = MultiBufferChunks {
4848            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4849                ..ExcerptDimension(MultiBufferOffset::ZERO),
4850            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4851            excerpts: self.excerpts.cursor(()),
4852            diff_transforms: self.diff_transforms.cursor(()),
4853            diffs: &self.diffs,
4854            diff_base_chunks: None,
4855            excerpt_chunks: None,
4856            buffer_chunk: None,
4857            language_aware,
4858        };
4859        let range = range.start.to_offset(self)..range.end.to_offset(self);
4860        chunks.seek(range);
4861        chunks
4862    }
4863
4864    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4865        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4866    }
4867
4868    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4869        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4870    }
4871
4872    pub fn clip_offset_utf16(
4873        &self,
4874        offset: MultiBufferOffsetUtf16,
4875        bias: Bias,
4876    ) -> MultiBufferOffsetUtf16 {
4877        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4878    }
4879
4880    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4881        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4882            buffer.clip_point_utf16(Unclipped(point), bias)
4883        })
4884    }
4885
4886    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4887        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4888    }
4889
4890    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4891        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4892    }
4893
4894    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4895        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4896    }
4897
4898    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4899        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4900    }
4901
4902    #[instrument(skip_all)]
4903    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4904        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4905    }
4906
4907    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4908        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4909    }
4910
4911    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4912        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4913    }
4914
4915    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4916        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4917    }
4918
4919    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4920        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4921    }
4922
4923    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4924        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4925    }
4926
4927    fn clip_dimension<MBD, BD>(
4928        &self,
4929        position: MBD,
4930        bias: Bias,
4931        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4932    ) -> MBD
4933    where
4934        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4935        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4936    {
4937        let mut cursor = self.cursor::<MBD, BD>();
4938        cursor.seek(&position);
4939        if let Some(region) = cursor.region() {
4940            if position >= region.range.end {
4941                return region.range.end;
4942            }
4943            let overshoot = position - region.range.start;
4944            let mut buffer_position = region.buffer_range.start;
4945            buffer_position += overshoot;
4946            let clipped_buffer_position =
4947                clip_buffer_position(region.buffer, buffer_position, bias);
4948            let mut position = region.range.start;
4949            position += clipped_buffer_position - region.buffer_range.start;
4950            position
4951        } else {
4952            self.max_position()
4953        }
4954    }
4955
4956    #[instrument(skip_all)]
4957    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4958        &self,
4959        key: MBR1,
4960        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4961    ) -> MBR2
4962    where
4963        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4964        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4965        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4966        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4967    {
4968        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4969        cursor.seek(&DimensionPair { key, value: None });
4970        if let Some(region) = cursor.region() {
4971            if key >= region.range.end.key {
4972                return region.range.end.value.unwrap();
4973            }
4974            let start_key = region.range.start.key;
4975            let start_value = region.range.start.value.unwrap();
4976            let buffer_start_key = region.buffer_range.start.key;
4977            let buffer_start_value = region.buffer_range.start.value.unwrap();
4978            let mut buffer_key = buffer_start_key;
4979            buffer_key += key - start_key;
4980            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4981            let mut result = start_value;
4982            result += buffer_value - buffer_start_value;
4983            result
4984        } else {
4985            self.max_position()
4986        }
4987    }
4988
4989    pub fn point_to_buffer_offset<T: ToOffset>(
4990        &self,
4991        point: T,
4992    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4993        let offset = point.to_offset(self);
4994        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4995        cursor.seek(&offset);
4996        let region = cursor.region()?;
4997        let overshoot = offset - region.range.start;
4998        let buffer_offset = region.buffer_range.start + overshoot;
4999        if buffer_offset == BufferOffset(region.buffer.len() + 1)
5000            && region.has_trailing_newline
5001            && !region.is_main_buffer
5002        {
5003            let main_buffer_position = cursor.main_buffer_position()?;
5004            let buffer_snapshot = &cursor.excerpt()?.buffer;
5005            return Some((buffer_snapshot, main_buffer_position));
5006        } else if buffer_offset > BufferOffset(region.buffer.len()) {
5007            return None;
5008        }
5009        Some((region.buffer, buffer_offset))
5010    }
5011
5012    pub fn point_to_buffer_point(
5013        &self,
5014        point: Point,
5015    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5016        let mut cursor = self.cursor::<Point, Point>();
5017        cursor.seek(&point);
5018        let region = cursor.region()?;
5019        let overshoot = point - region.range.start;
5020        let buffer_point = region.buffer_range.start + overshoot;
5021        let excerpt = cursor.excerpt()?;
5022        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5023            && region.has_trailing_newline
5024            && !region.is_main_buffer
5025        {
5026            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5027        } else if buffer_point > region.buffer.max_point() {
5028            return None;
5029        }
5030        Some((region.buffer, buffer_point, excerpt.id))
5031    }
5032
5033    pub fn suggested_indents(
5034        &self,
5035        rows: impl IntoIterator<Item = u32>,
5036        cx: &App,
5037    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5038        let mut result = BTreeMap::new();
5039        self.suggested_indents_callback(
5040            rows,
5041            &mut |row, indent| {
5042                result.insert(row, indent);
5043                ControlFlow::Continue(())
5044            },
5045            cx,
5046        );
5047        result
5048    }
5049
5050    // move this to be a generator once those are a thing
5051    pub fn suggested_indents_callback(
5052        &self,
5053        rows: impl IntoIterator<Item = u32>,
5054        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5055        cx: &App,
5056    ) {
5057        let mut rows_for_excerpt = Vec::new();
5058        let mut cursor = self.cursor::<Point, Point>();
5059        let mut rows = rows.into_iter().peekable();
5060        let mut prev_row = u32::MAX;
5061        let mut prev_language_indent_size = IndentSize::default();
5062
5063        while let Some(row) = rows.next() {
5064            cursor.seek(&Point::new(row, 0));
5065            let Some(region) = cursor.region() else {
5066                continue;
5067            };
5068
5069            // Retrieve the language and indent size once for each disjoint region being indented.
5070            let single_indent_size = if row.saturating_sub(1) == prev_row {
5071                prev_language_indent_size
5072            } else {
5073                region
5074                    .buffer
5075                    .language_indent_size_at(Point::new(row, 0), cx)
5076            };
5077            prev_language_indent_size = single_indent_size;
5078            prev_row = row;
5079
5080            let start_buffer_row = region.buffer_range.start.row;
5081            let start_multibuffer_row = region.range.start.row;
5082            let end_multibuffer_row = region.range.end.row;
5083
5084            rows_for_excerpt.push(row);
5085            while let Some(next_row) = rows.peek().copied() {
5086                if end_multibuffer_row > next_row {
5087                    rows_for_excerpt.push(next_row);
5088                    rows.next();
5089                } else {
5090                    break;
5091                }
5092            }
5093
5094            let buffer_rows = rows_for_excerpt
5095                .drain(..)
5096                .map(|row| start_buffer_row + row - start_multibuffer_row);
5097            let buffer_indents = region
5098                .buffer
5099                .suggested_indents(buffer_rows, single_indent_size);
5100            for (row, indent) in buffer_indents {
5101                if cb(
5102                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5103                    indent,
5104                )
5105                .is_break()
5106                {
5107                    return;
5108                }
5109            }
5110        }
5111    }
5112
5113    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5114        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5115            let mut size = buffer.indent_size_for_line(range.start.row);
5116            size.len = size
5117                .len
5118                .min(range.end.column)
5119                .saturating_sub(range.start.column);
5120            size
5121        } else {
5122            IndentSize::spaces(0)
5123        }
5124    }
5125
5126    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5127        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5128            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5129        } else {
5130            LineIndent::spaces(0)
5131        }
5132    }
5133
5134    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5135        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5136
5137        if self.language_settings(cx).extend_comment_on_newline
5138            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5139        {
5140            let delimiters = language_scope.line_comment_prefixes();
5141            for delimiter in delimiters {
5142                if *self
5143                    .chars_at(Point::new(row.0, indent.len() as u32))
5144                    .take(delimiter.chars().count())
5145                    .collect::<String>()
5146                    .as_str()
5147                    == **delimiter
5148                {
5149                    indent.push_str(delimiter);
5150                    break;
5151                }
5152            }
5153        }
5154
5155        indent
5156    }
5157
5158    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5159    where
5160        T: ToOffset,
5161    {
5162        for char in self.reversed_chars_at(position) {
5163            if !char.is_whitespace() {
5164                return false;
5165            }
5166            if char == '\n' {
5167                return true;
5168            }
5169        }
5170        true
5171    }
5172
5173    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5174        while row.0 > 0 {
5175            row.0 -= 1;
5176            if !self.is_line_blank(row) {
5177                return Some(row);
5178            }
5179        }
5180        None
5181    }
5182
5183    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5184        if let Some((_, range)) = self.buffer_line_for_row(row) {
5185            range.end.column - range.start.column
5186        } else {
5187            0
5188        }
5189    }
5190
5191    pub fn buffer_line_for_row(
5192        &self,
5193        row: MultiBufferRow,
5194    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5195        let mut cursor = self.cursor::<Point, Point>();
5196        let point = Point::new(row.0, 0);
5197        cursor.seek(&point);
5198        let region = cursor.region()?;
5199        let overshoot = point.min(region.range.end) - region.range.start;
5200        let buffer_point = region.buffer_range.start + overshoot;
5201        if buffer_point.row > region.buffer_range.end.row {
5202            return None;
5203        }
5204        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5205        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5206            .min(region.buffer_range.end);
5207        Some((region.buffer, line_start..line_end))
5208    }
5209
5210    pub fn max_point(&self) -> Point {
5211        self.text_summary().lines
5212    }
5213
5214    pub fn max_row(&self) -> MultiBufferRow {
5215        MultiBufferRow(self.text_summary().lines.row)
5216    }
5217
5218    pub fn text_summary(&self) -> MBTextSummary {
5219        self.diff_transforms.summary().output
5220    }
5221
5222    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5223    where
5224        MBD: MultiBufferDimension + AddAssign,
5225        O: ToOffset,
5226    {
5227        let range = range.start.to_offset(self)..range.end.to_offset(self);
5228        let mut cursor = self
5229            .diff_transforms
5230            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5231        cursor.seek(&range.start, Bias::Right);
5232
5233        let Some(first_transform) = cursor.item() else {
5234            return MBD::from_summary(&MBTextSummary::default());
5235        };
5236
5237        let diff_transform_start = cursor.start().0;
5238        let diff_transform_end = cursor.end().0;
5239        let diff_start = range.start;
5240        let start_overshoot = diff_start - diff_transform_start;
5241        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5242
5243        let mut result = match first_transform {
5244            DiffTransform::BufferContent { .. } => {
5245                let excerpt_start = cursor.start().1 + start_overshoot;
5246                let excerpt_end = cursor.start().1 + end_overshoot;
5247                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5248            }
5249            DiffTransform::DeletedHunk {
5250                buffer_id,
5251                base_text_byte_range,
5252                has_trailing_newline,
5253                ..
5254            } => {
5255                let buffer_start = base_text_byte_range.start + start_overshoot;
5256                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5257                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5258                    panic!("{:?} is in non-existent deleted hunk", range.start)
5259                };
5260
5261                let include_trailing_newline =
5262                    *has_trailing_newline && range.end >= diff_transform_end;
5263                if include_trailing_newline {
5264                    buffer_end -= 1;
5265                }
5266
5267                let mut summary = base_text
5268                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5269
5270                if include_trailing_newline {
5271                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5272                        &TextSummary::newline(),
5273                    ))
5274                }
5275
5276                let mut result = MBD::default();
5277                result.add_text_dim(&summary);
5278                result
5279            }
5280        };
5281        if range.end < diff_transform_end {
5282            return result;
5283        }
5284
5285        cursor.next();
5286        result.add_mb_text_summary(
5287            &cursor
5288                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5289                .0,
5290        );
5291
5292        let Some(last_transform) = cursor.item() else {
5293            return result;
5294        };
5295
5296        let overshoot = range.end - cursor.start().0;
5297        let suffix = match last_transform {
5298            DiffTransform::BufferContent { .. } => {
5299                let end = cursor.start().1 + overshoot;
5300                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5301            }
5302            DiffTransform::DeletedHunk {
5303                base_text_byte_range,
5304                buffer_id,
5305                has_trailing_newline,
5306                ..
5307            } => {
5308                let buffer_end = base_text_byte_range.start + overshoot;
5309                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5310                    panic!("{:?} is in non-existent deleted hunk", range.end)
5311                };
5312
5313                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5314                    base_text_byte_range.start..buffer_end,
5315                );
5316                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5317                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5318                        &TextSummary::from("\n"),
5319                    ))
5320                }
5321
5322                let mut result = MBD::default();
5323                result.add_text_dim(&suffix);
5324                result
5325            }
5326        };
5327
5328        result += suffix;
5329        result
5330    }
5331
5332    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5333    where
5334        MBD: MultiBufferDimension + AddAssign,
5335    {
5336        let mut summary = MBD::default();
5337        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5338        cursor.seek(&range.start, Bias::Right);
5339        if let Some(excerpt) = cursor.item() {
5340            let mut end_before_newline = cursor.end();
5341            if excerpt.has_trailing_newline {
5342                end_before_newline -= 1;
5343            }
5344
5345            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5346            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5347            let end_in_excerpt =
5348                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5349            summary.add_text_dim(
5350                &excerpt
5351                    .buffer
5352                    .text_summary_for_range::<MBD::TextDimension, _>(
5353                        start_in_excerpt..end_in_excerpt,
5354                    ),
5355            );
5356
5357            if range.end > end_before_newline {
5358                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5359            }
5360
5361            cursor.next();
5362        }
5363
5364        if range.end > *cursor.start() {
5365            summary += cursor
5366                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5367                .0;
5368            if let Some(excerpt) = cursor.item() {
5369                range.end = cmp::max(*cursor.start(), range.end);
5370
5371                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5372                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5373                summary.add_text_dim(
5374                    &excerpt
5375                        .buffer
5376                        .text_summary_for_range::<MBD::TextDimension, _>(
5377                            excerpt_start..end_in_excerpt,
5378                        ),
5379                );
5380            }
5381        }
5382
5383        summary
5384    }
5385
5386    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5387    where
5388        MBD: MultiBufferDimension
5389            + Ord
5390            + Sub<Output = MBD::TextDimension>
5391            + Sub<MBD::TextDimension, Output = MBD>
5392            + AddAssign<MBD::TextDimension>
5393            + Add<MBD::TextDimension, Output = MBD>,
5394        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5395    {
5396        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5397        let locator = self.excerpt_locator_for_id(excerpt_id);
5398        let (start, _, mut item) = self
5399            .excerpts
5400            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5401        let mut start = MBD::from_summary(&start.text);
5402        if item.is_none() && excerpt_id == ExcerptId::max() {
5403            item = self.excerpts.last();
5404            if let Some(last_summary) = self.excerpts.last_summary() {
5405                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5406            }
5407        }
5408
5409        let excerpt_start_position = ExcerptDimension(start);
5410        if self.diff_transforms.is_empty() {
5411            if let Some(excerpt) = item {
5412                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5413                    return excerpt_start_position.0;
5414                }
5415                let excerpt_buffer_start = excerpt
5416                    .range
5417                    .context
5418                    .start
5419                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5420                let excerpt_buffer_end = excerpt
5421                    .range
5422                    .context
5423                    .end
5424                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5425                let buffer_summary = anchor
5426                    .text_anchor
5427                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5428                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5429                let mut position = excerpt_start_position;
5430                if summary > excerpt_buffer_start {
5431                    position += summary - excerpt_buffer_start;
5432                }
5433
5434                position.0
5435            } else {
5436                excerpt_start_position.0
5437            }
5438        } else {
5439            let mut diff_transforms_cursor = self
5440                .diff_transforms
5441                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5442            diff_transforms_cursor.next();
5443
5444            if let Some(excerpt) = item {
5445                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5446                    return self.resolve_summary_for_min_or_max_anchor(
5447                        &Anchor::min(),
5448                        excerpt_start_position,
5449                        &mut diff_transforms_cursor,
5450                    );
5451                }
5452                let excerpt_buffer_start = excerpt
5453                    .range
5454                    .context
5455                    .start
5456                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5457                let excerpt_buffer_end = excerpt
5458                    .range
5459                    .context
5460                    .end
5461                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5462                let buffer_summary = anchor
5463                    .text_anchor
5464                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5465                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5466                let mut position = excerpt_start_position;
5467                if summary > excerpt_buffer_start {
5468                    position += summary - excerpt_buffer_start;
5469                }
5470
5471                if diff_transforms_cursor.start().0 < position {
5472                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5473                }
5474                self.resolve_summary_for_anchor(
5475                    &anchor,
5476                    position,
5477                    &mut diff_transforms_cursor,
5478                    &excerpt.buffer,
5479                )
5480            } else {
5481                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5482                self.resolve_summary_for_min_or_max_anchor(
5483                    &Anchor::max(),
5484                    excerpt_start_position,
5485                    &mut diff_transforms_cursor,
5486                )
5487            }
5488        }
5489    }
5490
5491    /// Maps an anchor's excerpt-space position to its output-space position by
5492    /// walking the diff transforms. The cursor is shared across consecutive
5493    /// calls, so it may already be partway through the transform list.
5494    fn resolve_summary_for_anchor<MBD>(
5495        &self,
5496        anchor: &Anchor,
5497        excerpt_position: ExcerptDimension<MBD>,
5498        diff_transforms: &mut Cursor<
5499            DiffTransform,
5500            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5501        >,
5502        excerpt_buffer: &text::BufferSnapshot,
5503    ) -> MBD
5504    where
5505        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5506    {
5507        loop {
5508            let transform_end_position = diff_transforms.end().0;
5509            let item = diff_transforms.item();
5510            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5511
5512            // A right-biased anchor at a transform boundary belongs to the
5513            // *next* transform, so advance past the current one.
5514            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5515                diff_transforms.next();
5516                continue;
5517            }
5518
5519            let mut position = diff_transforms.start().1;
5520            match item {
5521                Some(DiffTransform::DeletedHunk {
5522                    buffer_id,
5523                    base_text_byte_range,
5524                    hunk_info,
5525                    ..
5526                }) => {
5527                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5528                        && let Some(base_text) =
5529                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5530                        && diff_base_anchor.is_valid(&base_text)
5531                    {
5532                        // The anchor carries a diff-base position — resolve it
5533                        // to a location inside the deleted hunk.
5534                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5535                        if base_text_offset >= base_text_byte_range.start
5536                            && base_text_offset <= base_text_byte_range.end
5537                        {
5538                            let position_in_hunk = base_text
5539                                .text_summary_for_range::<MBD::TextDimension, _>(
5540                                    base_text_byte_range.start..base_text_offset,
5541                                );
5542                            position.0.add_text_dim(&position_in_hunk);
5543                        } else if at_transform_end {
5544                            // diff_base offset falls outside this hunk's range;
5545                            // advance to see if the next transform is a better fit.
5546                            diff_transforms.next();
5547                            continue;
5548                        }
5549                    } else if at_transform_end
5550                        && anchor
5551                            .text_anchor
5552                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5553                            .is_gt()
5554                    {
5555                        // The anchor has no (valid) diff-base position, so it
5556                        // belongs in the buffer content, not in the deleted
5557                        // hunk. However, after an edit deletes the text between
5558                        // the hunk boundary and this anchor, both resolve to
5559                        // the same excerpt_position—landing us here on the
5560                        // DeletedHunk left behind by the shared cursor. Use the
5561                        // CRDT ordering to detect that the anchor is strictly
5562                        // *past* the hunk boundary and skip to the following
5563                        // BufferContent.
5564                        diff_transforms.next();
5565                        continue;
5566                    }
5567                }
5568                _ => {
5569                    // On a BufferContent (or no transform). If the anchor
5570                    // carries a diff_base_anchor it needs a DeletedHunk, so
5571                    // advance to find one.
5572                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5573                        diff_transforms.next();
5574                        continue;
5575                    }
5576                    let overshoot = excerpt_position - diff_transforms.start().0;
5577                    position += overshoot;
5578                }
5579            }
5580
5581            return position.0;
5582        }
5583    }
5584
5585    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5586    fn resolve_summary_for_min_or_max_anchor<MBD>(
5587        &self,
5588        anchor: &Anchor,
5589        excerpt_position: ExcerptDimension<MBD>,
5590        diff_transforms: &mut Cursor<
5591            DiffTransform,
5592            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5593        >,
5594    ) -> MBD
5595    where
5596        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5597    {
5598        loop {
5599            let transform_end_position = diff_transforms.end().0;
5600            let item = diff_transforms.item();
5601            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5602
5603            // A right-biased anchor at a transform boundary belongs to the
5604            // *next* transform, so advance past the current one.
5605            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5606                diff_transforms.next();
5607                continue;
5608            }
5609
5610            let mut position = diff_transforms.start().1;
5611            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5612                let overshoot = excerpt_position - diff_transforms.start().0;
5613                position += overshoot;
5614            }
5615
5616            return position.0;
5617        }
5618    }
5619
5620    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5621        let mut cursor = self
5622            .excerpts
5623            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5624        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5625
5626        cursor.seek(&Some(locator), Bias::Left);
5627        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5628            cursor.prev();
5629        }
5630
5631        let mut position = cursor.start().1;
5632        if let Some(excerpt) = cursor.item()
5633            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5634        {
5635            let excerpt_buffer_start = excerpt
5636                .buffer
5637                .offset_for_anchor(&excerpt.range.context.start);
5638            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5639            let buffer_position = cmp::min(
5640                excerpt_buffer_end,
5641                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5642            );
5643            if buffer_position > excerpt_buffer_start {
5644                position += buffer_position - excerpt_buffer_start;
5645            }
5646        }
5647        position
5648    }
5649
5650    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5651        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5652            excerpt_id = *replacement;
5653        }
5654        excerpt_id
5655    }
5656
5657    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5658    where
5659        MBD: MultiBufferDimension
5660            + Ord
5661            + Sub<Output = MBD::TextDimension>
5662            + AddAssign<MBD::TextDimension>,
5663        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5664        I: 'a + IntoIterator<Item = &'a Anchor>,
5665    {
5666        let mut anchors = anchors.into_iter().peekable();
5667        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5668        let mut diff_transforms_cursor = self
5669            .diff_transforms
5670            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5671        diff_transforms_cursor.next();
5672
5673        let mut summaries = Vec::new();
5674        while let Some(anchor) = anchors.peek() {
5675            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5676
5677            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5678                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5679            });
5680
5681            let locator = self.excerpt_locator_for_id(excerpt_id);
5682            cursor.seek_forward(locator, Bias::Left);
5683            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5684                cursor.prev();
5685            }
5686
5687            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5688            if let Some(excerpt) = cursor.item() {
5689                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5690                    let position = self.resolve_summary_for_min_or_max_anchor(
5691                        &Anchor::min(),
5692                        excerpt_start_position,
5693                        &mut diff_transforms_cursor,
5694                    );
5695                    summaries.extend(excerpt_anchors.map(|_| position));
5696                    continue;
5697                }
5698                let excerpt_buffer_start = excerpt
5699                    .range
5700                    .context
5701                    .start
5702                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5703                let excerpt_buffer_end = excerpt
5704                    .range
5705                    .context
5706                    .end
5707                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5708                for (buffer_summary, anchor) in excerpt
5709                    .buffer
5710                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5711                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5712                    )
5713                {
5714                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5715                    let mut position = excerpt_start_position;
5716                    if summary > excerpt_buffer_start {
5717                        position += summary - excerpt_buffer_start;
5718                    }
5719
5720                    if diff_transforms_cursor.start().0 < position {
5721                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5722                    }
5723
5724                    summaries.push(self.resolve_summary_for_anchor(
5725                        anchor,
5726                        position,
5727                        &mut diff_transforms_cursor,
5728                        &excerpt.buffer,
5729                    ));
5730                }
5731            } else {
5732                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5733                let position = self.resolve_summary_for_min_or_max_anchor(
5734                    &Anchor::max(),
5735                    excerpt_start_position,
5736                    &mut diff_transforms_cursor,
5737                );
5738                summaries.extend(excerpt_anchors.map(|_| position));
5739            }
5740        }
5741
5742        summaries
5743    }
5744
5745    pub fn dimensions_from_points<'a, MBD>(
5746        &'a self,
5747        points: impl 'a + IntoIterator<Item = Point>,
5748    ) -> impl 'a + Iterator<Item = MBD>
5749    where
5750        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5751    {
5752        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5753        cursor.seek(&DimensionPair {
5754            key: Point::default(),
5755            value: None,
5756        });
5757        let mut points = points.into_iter();
5758        iter::from_fn(move || {
5759            let point = points.next()?;
5760
5761            cursor.seek_forward(&DimensionPair {
5762                key: point,
5763                value: None,
5764            });
5765
5766            if let Some(region) = cursor.region() {
5767                let overshoot = point - region.range.start.key;
5768                let buffer_point = region.buffer_range.start + overshoot;
5769                let mut position = region.range.start.value.unwrap();
5770                position.add_text_dim(
5771                    &region
5772                        .buffer
5773                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5774                );
5775                if point == region.range.end.key && region.has_trailing_newline {
5776                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5777                }
5778                Some(position)
5779            } else {
5780                Some(MBD::from_summary(&self.text_summary()))
5781            }
5782        })
5783    }
5784
5785    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5786    where
5787        I: 'a + IntoIterator<Item = &'a Anchor>,
5788    {
5789        let mut anchors = anchors.into_iter().enumerate().peekable();
5790        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5791        cursor.next();
5792
5793        let mut result = Vec::new();
5794
5795        while let Some((_, anchor)) = anchors.peek() {
5796            let old_excerpt_id = anchor.excerpt_id;
5797
5798            // Find the location where this anchor's excerpt should be.
5799            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5800            cursor.seek_forward(&Some(old_locator), Bias::Left);
5801
5802            let next_excerpt = cursor.item();
5803            let prev_excerpt = cursor.prev_item();
5804
5805            // Process all of the anchors for this excerpt.
5806            while let Some((anchor_ix, &anchor)) =
5807                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5808            {
5809                let mut anchor = anchor;
5810
5811                // Leave min and max anchors unchanged if invalid or
5812                // if the old excerpt still exists at this location
5813                let mut kept_position = next_excerpt
5814                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5815                    || old_excerpt_id == ExcerptId::max()
5816                    || old_excerpt_id == ExcerptId::min();
5817
5818                // If the old excerpt no longer exists at this location, then attempt to
5819                // find an equivalent position for this anchor in an adjacent excerpt.
5820                if !kept_position {
5821                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5822                        if excerpt.contains(&anchor) {
5823                            anchor.excerpt_id = excerpt.id;
5824                            kept_position = true;
5825                            break;
5826                        }
5827                    }
5828                }
5829
5830                // If there's no adjacent excerpt that contains the anchor's position,
5831                // then report that the anchor has lost its position.
5832                if !kept_position {
5833                    anchor = if let Some(excerpt) = next_excerpt {
5834                        let mut text_anchor = excerpt
5835                            .range
5836                            .context
5837                            .start
5838                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5839                        if text_anchor
5840                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5841                            .is_gt()
5842                        {
5843                            text_anchor = excerpt.range.context.end;
5844                        }
5845                        Anchor::in_buffer(excerpt.id, text_anchor)
5846                    } else if let Some(excerpt) = prev_excerpt {
5847                        let mut text_anchor = excerpt
5848                            .range
5849                            .context
5850                            .end
5851                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5852                        if text_anchor
5853                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5854                            .is_lt()
5855                        {
5856                            text_anchor = excerpt.range.context.start;
5857                        }
5858                        Anchor::in_buffer(excerpt.id, text_anchor)
5859                    } else if anchor.text_anchor.bias == Bias::Left {
5860                        Anchor::min()
5861                    } else {
5862                        Anchor::max()
5863                    };
5864                }
5865
5866                result.push((anchor_ix, anchor, kept_position));
5867            }
5868        }
5869        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5870        result
5871    }
5872
5873    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5874        self.anchor_at(position, Bias::Left)
5875    }
5876
5877    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5878        self.anchor_at(position, Bias::Right)
5879    }
5880
5881    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5882        let offset = position.to_offset(self);
5883
5884        // Find the given position in the diff transforms. Determine the corresponding
5885        // offset in the excerpts, and whether the position is within a deleted hunk.
5886        let mut diff_transforms = self
5887            .diff_transforms
5888            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5889        diff_transforms.seek(&offset, Bias::Right);
5890
5891        if offset == diff_transforms.start().0
5892            && bias == Bias::Left
5893            && let Some(prev_item) = diff_transforms.prev_item()
5894            && let DiffTransform::DeletedHunk { .. } = prev_item
5895        {
5896            diff_transforms.prev();
5897        }
5898        let offset_in_transform = offset - diff_transforms.start().0;
5899        let mut excerpt_offset = diff_transforms.start().1;
5900        let mut diff_base_anchor = None;
5901        if let Some(DiffTransform::DeletedHunk {
5902            buffer_id,
5903            base_text_byte_range,
5904            has_trailing_newline,
5905            ..
5906        }) = diff_transforms.item()
5907        {
5908            let diff = self.diffs.get(buffer_id).expect("missing diff");
5909            if offset_in_transform > base_text_byte_range.len() {
5910                debug_assert!(*has_trailing_newline);
5911                bias = Bias::Right;
5912            } else {
5913                diff_base_anchor = Some(
5914                    diff.base_text()
5915                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5916                );
5917                bias = Bias::Left;
5918            }
5919        } else {
5920            excerpt_offset += MultiBufferOffset(offset_in_transform);
5921        };
5922
5923        let mut excerpts = self
5924            .excerpts
5925            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5926        excerpts.seek(&excerpt_offset, Bias::Right);
5927        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5928            excerpts.prev();
5929        }
5930        if let Some(excerpt) = excerpts.item() {
5931            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5932            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5933                overshoot -= 1;
5934                bias = Bias::Right;
5935            }
5936
5937            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5938            let text_anchor =
5939                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5940            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5941            match diff_base_anchor {
5942                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5943                None => anchor,
5944            }
5945        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5946        {
5947            Anchor::min()
5948        } else {
5949            Anchor::max()
5950        }
5951    }
5952
5953    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5954    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5955        let (excerpt, buffer, _) = self.as_singleton()?;
5956        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5957            Some(Anchor::in_buffer(excerpt, text_anchor))
5958        } else {
5959            None
5960        }
5961    }
5962
5963    /// Returns an anchor for the given excerpt and text anchor,
5964    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5965    pub fn anchor_range_in_excerpt(
5966        &self,
5967        excerpt_id: ExcerptId,
5968        text_anchor: Range<text::Anchor>,
5969    ) -> Option<Range<Anchor>> {
5970        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5971
5972        Some(
5973            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5974                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5975        )
5976    }
5977
5978    /// Returns an anchor for the given excerpt and text anchor,
5979    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5980    pub fn anchor_in_excerpt(
5981        &self,
5982        excerpt_id: ExcerptId,
5983        text_anchor: text::Anchor,
5984    ) -> Option<Anchor> {
5985        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5986        Self::anchor_in_excerpt_(excerpt, text_anchor)
5987    }
5988
5989    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5990    pub fn anchors_in_excerpt(
5991        &self,
5992        excerpt_id: ExcerptId,
5993        text_anchors: impl IntoIterator<Item = text::Anchor>,
5994    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5995        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5996        Some(
5997            text_anchors
5998                .into_iter()
5999                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
6000        )
6001    }
6002
6003    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
6004        match text_anchor.buffer_id {
6005            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
6006            Some(_) => return None,
6007            None if text_anchor.is_max() || text_anchor.is_min() => {
6008                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
6009            }
6010            None => return None,
6011        }
6012
6013        let context = &excerpt.range.context;
6014        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6015            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6016        {
6017            return None;
6018        }
6019
6020        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6021    }
6022
6023    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6024        Some(self.excerpt(excerpt_id)?.range.context.clone())
6025    }
6026
6027    pub fn excerpt_range_for_excerpt(
6028        &self,
6029        excerpt_id: ExcerptId,
6030    ) -> Option<ExcerptRange<text::Anchor>> {
6031        Some(self.excerpt(excerpt_id)?.range.clone())
6032    }
6033
6034    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6035        if anchor.is_min() || anchor.is_max() {
6036            // todo(lw): should be `!self.is_empty()`
6037            true
6038        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6039            excerpt.buffer.can_resolve(&anchor.text_anchor)
6040        } else {
6041            false
6042        }
6043    }
6044
6045    pub fn excerpts(
6046        &self,
6047    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6048        self.excerpts
6049            .iter()
6050            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6051    }
6052
6053    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6054    where
6055        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6056        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6057    {
6058        let excerpts = self.excerpts.cursor(());
6059        let diff_transforms = self.diff_transforms.cursor(());
6060        MultiBufferCursor {
6061            excerpts,
6062            diff_transforms,
6063            diffs: &self.diffs,
6064            cached_region: OnceCell::new(),
6065        }
6066    }
6067
6068    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6069        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6070        let mut excerpts = self
6071            .excerpts
6072            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6073        excerpts.seek(&Some(start_locator), Bias::Left);
6074        excerpts.prev();
6075
6076        let mut diff_transforms = self
6077            .diff_transforms
6078            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6079        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6080        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6081            diff_transforms.next();
6082        }
6083
6084        let excerpt = excerpts.item()?;
6085        Some(MultiBufferExcerpt {
6086            excerpt,
6087            offset: diff_transforms.start().output_dimension.0,
6088            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6089            excerpt_offset: excerpts.start().1,
6090            diff_transforms,
6091        })
6092    }
6093
6094    pub fn excerpt_boundaries_in_range<R, T>(
6095        &self,
6096        range: R,
6097    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6098    where
6099        R: RangeBounds<T>,
6100        T: ToOffset,
6101    {
6102        let start_offset;
6103        let start = match range.start_bound() {
6104            Bound::Included(start) => {
6105                start_offset = start.to_offset(self);
6106                Bound::Included(start_offset)
6107            }
6108            Bound::Excluded(_) => {
6109                panic!("not supported")
6110            }
6111            Bound::Unbounded => {
6112                start_offset = MultiBufferOffset::ZERO;
6113                Bound::Unbounded
6114            }
6115        };
6116        let end = match range.end_bound() {
6117            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6118            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6119            Bound::Unbounded => Bound::Unbounded,
6120        };
6121        let bounds = (start, end);
6122        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6123        cursor.seek(&DimensionPair {
6124            key: start_offset,
6125            value: None,
6126        });
6127
6128        if cursor
6129            .fetch_excerpt_with_range()
6130            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6131        {
6132            cursor.prev_excerpt();
6133        } else {
6134            cursor.seek_to_start_of_current_excerpt();
6135        }
6136        let mut prev_region = cursor
6137            .fetch_excerpt_with_range()
6138            .map(|(excerpt, _)| excerpt);
6139
6140        cursor.next_excerpt_forwards();
6141
6142        iter::from_fn(move || {
6143            loop {
6144                if self.singleton {
6145                    return None;
6146                }
6147
6148                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6149                cursor.next_excerpt_forwards();
6150                if !bounds.contains(&next_range.start.key) {
6151                    prev_region = Some(next_excerpt);
6152                    continue;
6153                }
6154
6155                let next_region_start = next_range.start.value.unwrap();
6156                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6157                    range.start.value.unwrap()
6158                } else {
6159                    self.max_point()
6160                };
6161
6162                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6163                    id: region.id,
6164                    buffer: region.buffer.clone(),
6165                    buffer_id: region.buffer_id,
6166                    range: region.range.clone(),
6167                    end_row: MultiBufferRow(next_region_start.row),
6168                });
6169
6170                let next = ExcerptInfo {
6171                    id: next_excerpt.id,
6172                    buffer: next_excerpt.buffer.clone(),
6173                    buffer_id: next_excerpt.buffer_id,
6174                    range: next_excerpt.range.clone(),
6175                    end_row: if next_excerpt.has_trailing_newline {
6176                        MultiBufferRow(next_region_end.row - 1)
6177                    } else {
6178                        MultiBufferRow(next_region_end.row)
6179                    },
6180                };
6181
6182                let row = MultiBufferRow(next_region_start.row);
6183
6184                prev_region = Some(next_excerpt);
6185
6186                return Some(ExcerptBoundary { row, prev, next });
6187            }
6188        })
6189    }
6190
6191    pub fn edit_count(&self) -> usize {
6192        self.edit_count
6193    }
6194
6195    pub fn non_text_state_update_count(&self) -> usize {
6196        self.non_text_state_update_count
6197    }
6198
6199    /// Returns the smallest enclosing bracket ranges containing the given range or
6200    /// None if no brackets contain range or the range is not contained in a single
6201    /// excerpt
6202    ///
6203    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6204    #[ztracing::instrument(skip_all)]
6205    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6206        &self,
6207        range: Range<T>,
6208        range_filter: Option<
6209            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6210        >,
6211    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6212        let range = range.start.to_offset(self)..range.end.to_offset(self);
6213        let mut excerpt = self.excerpt_containing(range.clone())?;
6214        let buffer = excerpt.buffer();
6215        let excerpt_buffer_range = excerpt.buffer_range();
6216
6217        // Filter to ranges contained in the excerpt
6218        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6219            excerpt_buffer_range.contains(&BufferOffset(open.start))
6220                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6221                && range_filter.is_none_or(|filter| {
6222                    filter(
6223                        buffer,
6224                        BufferOffset(open.start)..BufferOffset(close.end),
6225                        BufferOffset(close.start)..BufferOffset(close.end),
6226                    )
6227                })
6228        };
6229
6230        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6231            excerpt.map_range_to_buffer(range),
6232            Some(&range_filter),
6233        )?;
6234
6235        Some((
6236            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6237            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6238        ))
6239    }
6240
6241    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6242    /// not contained in a single excerpt
6243    pub fn enclosing_bracket_ranges<T: ToOffset>(
6244        &self,
6245        range: Range<T>,
6246    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6247    {
6248        let range = range.start.to_offset(self)..range.end.to_offset(self);
6249        let mut excerpt = self.excerpt_containing(range.clone())?;
6250
6251        Some(
6252            excerpt
6253                .buffer()
6254                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6255                .filter_map(move |pair| {
6256                    let open_range =
6257                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6258                    let close_range =
6259                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6260                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6261                        Some((
6262                            excerpt.map_range_from_buffer(open_range),
6263                            excerpt.map_range_from_buffer(close_range),
6264                        ))
6265                    } else {
6266                        None
6267                    }
6268                }),
6269        )
6270    }
6271
6272    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6273    /// not contained in a single excerpt
6274    pub fn text_object_ranges<T: ToOffset>(
6275        &self,
6276        range: Range<T>,
6277        options: TreeSitterOptions,
6278    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6279        let range = range.start.to_offset(self)..range.end.to_offset(self);
6280        self.excerpt_containing(range.clone())
6281            .map(|mut excerpt| {
6282                excerpt
6283                    .buffer()
6284                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6285                    .filter_map(move |(range, text_object)| {
6286                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6287                        if excerpt.contains_buffer_range(range.clone()) {
6288                            Some((excerpt.map_range_from_buffer(range), text_object))
6289                        } else {
6290                            None
6291                        }
6292                    })
6293            })
6294            .into_iter()
6295            .flatten()
6296    }
6297
6298    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6299    /// not contained in a single excerpt
6300    pub fn bracket_ranges<T: ToOffset>(
6301        &self,
6302        range: Range<T>,
6303    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6304    {
6305        let range = range.start.to_offset(self)..range.end.to_offset(self);
6306        let mut excerpt = self.excerpt_containing(range.clone())?;
6307        Some(
6308            excerpt
6309                .buffer()
6310                .bracket_ranges(excerpt.map_range_to_buffer(range))
6311                .filter_map(move |pair| {
6312                    let open_range =
6313                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6314                    let close_range =
6315                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6316                    excerpt
6317                        .contains_buffer_range(open_range.start..close_range.end)
6318                        .then(|| BracketMatch {
6319                            open_range: excerpt.map_range_from_buffer(open_range),
6320                            close_range: excerpt.map_range_from_buffer(close_range),
6321                            color_index: pair.color_index,
6322                            newline_only: pair.newline_only,
6323                            syntax_layer_depth: pair.syntax_layer_depth,
6324                        })
6325                })
6326                .map(BracketMatch::bracket_ranges),
6327        )
6328    }
6329
6330    pub fn redacted_ranges<'a, T: ToOffset>(
6331        &'a self,
6332        range: Range<T>,
6333        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6334    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6335        let range = range.start.to_offset(self)..range.end.to_offset(self);
6336        self.lift_buffer_metadata(range, move |buffer, range| {
6337            if redaction_enabled(buffer.file()) {
6338                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6339            } else {
6340                None
6341            }
6342        })
6343        .map(|(range, _, _)| range)
6344    }
6345
6346    pub fn runnable_ranges(
6347        &self,
6348        range: Range<Anchor>,
6349    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6350        let range = range.start.to_offset(self)..range.end.to_offset(self);
6351        self.lift_buffer_metadata(range, move |buffer, range| {
6352            Some(
6353                buffer
6354                    .runnable_ranges(range.clone())
6355                    .filter(move |runnable| {
6356                        runnable.run_range.start >= range.start
6357                            && runnable.run_range.end < range.end
6358                    })
6359                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6360            )
6361        })
6362        .map(|(run_range, runnable, _)| (run_range, runnable))
6363    }
6364
6365    pub fn line_indents(
6366        &self,
6367        start_row: MultiBufferRow,
6368        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6369    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6370        let max_point = self.max_point();
6371        let mut cursor = self.cursor::<Point, Point>();
6372        cursor.seek(&Point::new(start_row.0, 0));
6373        iter::from_fn(move || {
6374            let mut region = cursor.region()?;
6375            while !buffer_filter(&region.excerpt.buffer) {
6376                cursor.next();
6377                region = cursor.region()?;
6378            }
6379            let region = cursor.region()?;
6380            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6381            let buffer_start_row =
6382                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6383
6384            let buffer_end_row = if region.is_main_buffer
6385                && (region.has_trailing_newline || region.range.end == max_point)
6386            {
6387                region.buffer_range.end.row
6388            } else {
6389                region.buffer_range.end.row.saturating_sub(1)
6390            };
6391
6392            let line_indents = region
6393                .buffer
6394                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6395            let region_buffer_row = region.buffer_range.start.row;
6396            let region_row = region.range.start.row;
6397            let region_buffer = &region.excerpt.buffer;
6398            cursor.next();
6399            Some(line_indents.map(move |(buffer_row, indent)| {
6400                let row = region_row + (buffer_row - region_buffer_row);
6401                (MultiBufferRow(row), indent, region_buffer.as_ref())
6402            }))
6403        })
6404        .flatten()
6405    }
6406
6407    pub fn reversed_line_indents(
6408        &self,
6409        end_row: MultiBufferRow,
6410        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6411    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6412        let max_point = self.max_point();
6413        let mut cursor = self.cursor::<Point, Point>();
6414        cursor.seek(&Point::new(end_row.0, 0));
6415        iter::from_fn(move || {
6416            let mut region = cursor.region()?;
6417            while !buffer_filter(&region.excerpt.buffer) {
6418                cursor.prev();
6419                region = cursor.region()?;
6420            }
6421            let region = cursor.region()?;
6422
6423            let buffer_start_row = region.buffer_range.start.row;
6424            let buffer_end_row = if region.is_main_buffer
6425                && (region.has_trailing_newline || region.range.end == max_point)
6426            {
6427                region.buffer_range.end.row + 1
6428            } else {
6429                region.buffer_range.end.row
6430            };
6431
6432            let overshoot = end_row.0 - region.range.start.row;
6433            let buffer_end_row =
6434                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6435
6436            let line_indents = region
6437                .buffer
6438                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6439            let region_buffer_row = region.buffer_range.start.row;
6440            let region_row = region.range.start.row;
6441            let region_buffer = &region.excerpt.buffer;
6442            cursor.prev();
6443            Some(line_indents.map(move |(buffer_row, indent)| {
6444                let row = region_row + (buffer_row - region_buffer_row);
6445                (MultiBufferRow(row), indent, region_buffer.as_ref())
6446            }))
6447        })
6448        .flatten()
6449    }
6450
6451    pub async fn enclosing_indent(
6452        &self,
6453        mut target_row: MultiBufferRow,
6454    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6455        let max_row = MultiBufferRow(self.max_point().row);
6456        if target_row >= max_row {
6457            return None;
6458        }
6459
6460        let mut target_indent = self.line_indent_for_row(target_row);
6461
6462        // If the current row is at the start of an indented block, we want to return this
6463        // block as the enclosing indent.
6464        if !target_indent.is_line_empty() && target_row < max_row {
6465            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6466            if !next_line_indent.is_line_empty()
6467                && target_indent.raw_len() < next_line_indent.raw_len()
6468            {
6469                target_indent = next_line_indent;
6470                target_row.0 += 1;
6471            }
6472        }
6473
6474        const SEARCH_ROW_LIMIT: u32 = 25000;
6475        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6476        const YIELD_INTERVAL: u32 = 100;
6477
6478        let mut accessed_row_counter = 0;
6479
6480        // If there is a blank line at the current row, search for the next non indented lines
6481        if target_indent.is_line_empty() {
6482            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6483            let end =
6484                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6485
6486            let mut non_empty_line_above = None;
6487            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6488                if row < start {
6489                    break;
6490                }
6491                accessed_row_counter += 1;
6492                if accessed_row_counter == YIELD_INTERVAL {
6493                    accessed_row_counter = 0;
6494                    yield_now().await;
6495                }
6496                if !indent.is_line_empty() {
6497                    non_empty_line_above = Some((row, indent));
6498                    break;
6499                }
6500            }
6501
6502            let mut non_empty_line_below = None;
6503            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6504                if row > end {
6505                    break;
6506                }
6507                accessed_row_counter += 1;
6508                if accessed_row_counter == YIELD_INTERVAL {
6509                    accessed_row_counter = 0;
6510                    yield_now().await;
6511                }
6512                if !indent.is_line_empty() {
6513                    non_empty_line_below = Some((row, indent));
6514                    break;
6515                }
6516            }
6517
6518            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6519                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6520                    if above_indent.raw_len() >= below_indent.raw_len() {
6521                        (above_row, above_indent)
6522                    } else {
6523                        (below_row, below_indent)
6524                    }
6525                }
6526                (Some(above), None) => above,
6527                (None, Some(below)) => below,
6528                _ => return None,
6529            };
6530
6531            target_indent = indent;
6532            target_row = row;
6533        }
6534
6535        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6536        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6537
6538        let mut start_indent = None;
6539        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6540            if row < start {
6541                break;
6542            }
6543            accessed_row_counter += 1;
6544            if accessed_row_counter == YIELD_INTERVAL {
6545                accessed_row_counter = 0;
6546                yield_now().await;
6547            }
6548            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6549                start_indent = Some((row, indent));
6550                break;
6551            }
6552        }
6553        let (start_row, start_indent_size) = start_indent?;
6554
6555        let mut end_indent = (end, None);
6556        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6557            if row > end {
6558                break;
6559            }
6560            accessed_row_counter += 1;
6561            if accessed_row_counter == YIELD_INTERVAL {
6562                accessed_row_counter = 0;
6563                yield_now().await;
6564            }
6565            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6566                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6567                break;
6568            }
6569        }
6570        let (end_row, end_indent_size) = end_indent;
6571
6572        let indent = if let Some(end_indent_size) = end_indent_size {
6573            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6574                start_indent_size
6575            } else {
6576                end_indent_size
6577            }
6578        } else {
6579            start_indent_size
6580        };
6581
6582        Some((start_row..end_row, indent))
6583    }
6584
6585    pub fn indent_guides_in_range<T: ToPoint>(
6586        &self,
6587        range: Range<T>,
6588        ignore_disabled_for_language: bool,
6589        cx: &App,
6590    ) -> impl Iterator<Item = IndentGuide> {
6591        let range = range.start.to_point(self)..range.end.to_point(self);
6592        let start_row = MultiBufferRow(range.start.row);
6593        let end_row = MultiBufferRow(range.end.row);
6594
6595        let mut row_indents = self.line_indents(start_row, |buffer| {
6596            let settings =
6597                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6598            settings.indent_guides.enabled || ignore_disabled_for_language
6599        });
6600
6601        let mut result = Vec::new();
6602        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6603
6604        let mut prev_settings = None;
6605        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6606            if first_row > end_row {
6607                break;
6608            }
6609            let current_depth = indent_stack.len() as u32;
6610
6611            // Avoid retrieving the language settings repeatedly for every buffer row.
6612            if let Some((prev_buffer_id, _)) = &prev_settings
6613                && prev_buffer_id != &buffer.remote_id()
6614            {
6615                prev_settings.take();
6616            }
6617            let settings = &prev_settings
6618                .get_or_insert_with(|| {
6619                    (
6620                        buffer.remote_id(),
6621                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6622                    )
6623                })
6624                .1;
6625            let tab_size = settings.tab_size.get();
6626
6627            // When encountering empty, continue until found useful line indent
6628            // then add to the indent stack with the depth found
6629            let mut found_indent = false;
6630            let mut last_row = first_row;
6631            if line_indent.is_line_blank() {
6632                while !found_indent {
6633                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6634                        break;
6635                    };
6636                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6637                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6638                        break;
6639                    }
6640
6641                    if new_line_indent.is_line_blank() {
6642                        continue;
6643                    }
6644                    last_row = target_row.min(end_row);
6645                    line_indent = new_line_indent;
6646                    found_indent = true;
6647                    break;
6648                }
6649            } else {
6650                found_indent = true
6651            }
6652
6653            let depth = if found_indent {
6654                line_indent.len(tab_size) / tab_size
6655            } else {
6656                0
6657            };
6658
6659            match depth.cmp(&current_depth) {
6660                cmp::Ordering::Less => {
6661                    for _ in 0..(current_depth - depth) {
6662                        let mut indent = indent_stack.pop().unwrap();
6663                        if last_row != first_row {
6664                            // In this case, we landed on an empty row, had to seek forward,
6665                            // and discovered that the indent we where on is ending.
6666                            // This means that the last display row must
6667                            // be on line that ends this indent range, so we
6668                            // should display the range up to the first non-empty line
6669                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6670                        }
6671
6672                        result.push(indent)
6673                    }
6674                }
6675                cmp::Ordering::Greater => {
6676                    for next_depth in current_depth..depth {
6677                        indent_stack.push(IndentGuide {
6678                            buffer_id: buffer.remote_id(),
6679                            start_row: first_row,
6680                            end_row: last_row,
6681                            depth: next_depth,
6682                            tab_size,
6683                            settings: settings.indent_guides.clone(),
6684                        });
6685                    }
6686                }
6687                _ => {}
6688            }
6689
6690            for indent in indent_stack.iter_mut() {
6691                indent.end_row = last_row;
6692            }
6693        }
6694
6695        result.extend(indent_stack);
6696        result.into_iter()
6697    }
6698
6699    pub fn trailing_excerpt_update_count(&self) -> usize {
6700        self.trailing_excerpt_update_count
6701    }
6702
6703    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6704        self.point_to_buffer_offset(point)
6705            .and_then(|(buffer, _)| buffer.file())
6706    }
6707
6708    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6709        self.point_to_buffer_offset(offset)
6710            .and_then(|(buffer, offset)| buffer.language_at(offset))
6711    }
6712
6713    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6714        self.excerpts
6715            .first()
6716            .map(|excerpt| &excerpt.buffer)
6717            .map(|buffer| {
6718                language_settings(
6719                    buffer.language().map(|language| language.name()),
6720                    buffer.file(),
6721                    cx,
6722                )
6723            })
6724            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6725    }
6726
6727    pub fn language_settings_at<'a, T: ToOffset>(
6728        &'a self,
6729        point: T,
6730        cx: &'a App,
6731    ) -> Cow<'a, LanguageSettings> {
6732        let mut language = None;
6733        let mut file = None;
6734        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6735            language = buffer.language_at(offset);
6736            file = buffer.file();
6737        }
6738        language_settings(language.map(|l| l.name()), file, cx)
6739    }
6740
6741    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6742        self.point_to_buffer_offset(point)
6743            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6744    }
6745
6746    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6747        self.point_to_buffer_offset(point)
6748            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6749            .unwrap_or_default()
6750    }
6751
6752    pub fn language_indent_size_at<T: ToOffset>(
6753        &self,
6754        position: T,
6755        cx: &App,
6756    ) -> Option<IndentSize> {
6757        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6758        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6759    }
6760
6761    pub fn is_dirty(&self) -> bool {
6762        self.is_dirty
6763    }
6764
6765    pub fn has_deleted_file(&self) -> bool {
6766        self.has_deleted_file
6767    }
6768
6769    pub fn has_conflict(&self) -> bool {
6770        self.has_conflict
6771    }
6772
6773    pub fn has_diagnostics(&self) -> bool {
6774        self.excerpts
6775            .iter()
6776            .any(|excerpt| excerpt.buffer.has_diagnostics())
6777    }
6778
6779    pub fn diagnostic_group(
6780        &self,
6781        buffer_id: BufferId,
6782        group_id: usize,
6783    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6784        self.lift_buffer_metadata::<Point, _, _>(
6785            Point::zero()..self.max_point(),
6786            move |buffer, range| {
6787                if buffer.remote_id() != buffer_id {
6788                    return None;
6789                };
6790                Some(
6791                    buffer
6792                        .diagnostics_in_range(range, false)
6793                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6794                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6795                )
6796            },
6797        )
6798        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6799    }
6800
6801    pub fn diagnostics_in_range<'a, MBD>(
6802        &'a self,
6803        range: Range<MBD>,
6804    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6805    where
6806        MBD::TextDimension: 'a
6807            + text::ToOffset
6808            + text::FromAnchor
6809            + Sub<Output = MBD::TextDimension>
6810            + fmt::Debug
6811            + ops::Add<Output = MBD::TextDimension>
6812            + ops::AddAssign
6813            + Ord,
6814        MBD: MultiBufferDimension
6815            + Ord
6816            + Sub<Output = MBD::TextDimension>
6817            + ops::Add<MBD::TextDimension, Output = MBD>
6818            + ops::AddAssign<MBD::TextDimension>
6819            + 'a,
6820    {
6821        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6822            Some(
6823                buffer
6824                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6825                    .map(|entry| (entry.range, entry.diagnostic)),
6826            )
6827        })
6828        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6829    }
6830
6831    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6832        &'a self,
6833        range: Range<MBD>,
6834    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6835    where
6836        MBD: MultiBufferDimension
6837            + Ord
6838            + Sub<Output = MBD::TextDimension>
6839            + ops::Add<MBD::TextDimension, Output = MBD>
6840            + ops::AddAssign<MBD::TextDimension>,
6841        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6842            + ops::Add<Output = MBD::TextDimension>
6843            + text::ToOffset
6844            + text::FromAnchor
6845            + AddAssign<MBD::TextDimension>
6846            + Ord,
6847    {
6848        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6849            Some(
6850                buffer
6851                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6852                    .map(|entry| (entry.range, entry.diagnostic)),
6853            )
6854        })
6855        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6856    }
6857
6858    pub fn syntax_ancestor<T: ToOffset>(
6859        &self,
6860        range: Range<T>,
6861    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6862        let range = range.start.to_offset(self)..range.end.to_offset(self);
6863        let mut excerpt = self.excerpt_containing(range.clone())?;
6864        let node = excerpt
6865            .buffer()
6866            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6867        let node_range = node.byte_range();
6868        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6869        if !excerpt.contains_buffer_range(node_range.clone()) {
6870            return None;
6871        };
6872        Some((node, excerpt.map_range_from_buffer(node_range)))
6873    }
6874
6875    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6876        let (excerpt_id, _, buffer) = self.as_singleton()?;
6877        let outline = buffer.outline(theme);
6878        Some(Outline::new(
6879            outline
6880                .items
6881                .into_iter()
6882                .flat_map(|item| {
6883                    Some(OutlineItem {
6884                        depth: item.depth,
6885                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6886                        source_range_for_text: self
6887                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6888                        text: item.text,
6889                        highlight_ranges: item.highlight_ranges,
6890                        name_ranges: item.name_ranges,
6891                        body_range: item.body_range.and_then(|body_range| {
6892                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6893                        }),
6894                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6895                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6896                        }),
6897                    })
6898                })
6899                .collect(),
6900        ))
6901    }
6902
6903    pub fn symbols_containing<T: ToOffset>(
6904        &self,
6905        offset: T,
6906        theme: Option<&SyntaxTheme>,
6907    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6908        let anchor = self.anchor_before(offset);
6909        let excerpt @ &Excerpt {
6910            id: excerpt_id,
6911            buffer_id,
6912            ref buffer,
6913            ..
6914        } = self.excerpt(anchor.excerpt_id)?;
6915        if cfg!(debug_assertions) {
6916            match anchor.text_anchor.buffer_id {
6917                // we clearly are hitting this according to sentry, but in what situations can this occur?
6918                Some(anchor_buffer_id) => {
6919                    assert_eq!(
6920                        anchor_buffer_id, buffer_id,
6921                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6922                    )
6923                }
6924                None => assert!(anchor.is_max()),
6925            }
6926        };
6927        Some((
6928            buffer_id,
6929            buffer
6930                .symbols_containing(anchor.text_anchor, theme)
6931                .into_iter()
6932                .flat_map(|item| {
6933                    Some(OutlineItem {
6934                        depth: item.depth,
6935                        source_range_for_text: Anchor::range_in_buffer(
6936                            excerpt_id,
6937                            item.source_range_for_text,
6938                        ),
6939                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6940                        text: item.text,
6941                        highlight_ranges: item.highlight_ranges,
6942                        name_ranges: item.name_ranges,
6943                        body_range: item
6944                            .body_range
6945                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6946                        annotation_range: item
6947                            .annotation_range
6948                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6949                    })
6950                })
6951                .collect(),
6952        ))
6953    }
6954
6955    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6956        self.try_excerpt_locator_for_id(id)
6957            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6958    }
6959
6960    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6961        if id == ExcerptId::min() {
6962            Some(Locator::min_ref())
6963        } else if id == ExcerptId::max() {
6964            Some(Locator::max_ref())
6965        } else {
6966            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6967            if let Some(entry) = item
6968                && entry.id == id
6969            {
6970                return Some(&entry.locator);
6971            }
6972            None
6973        }
6974    }
6975
6976    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6977    fn excerpt_locators_for_ids(
6978        &self,
6979        ids: impl IntoIterator<Item = ExcerptId>,
6980    ) -> SmallVec<[Locator; 1]> {
6981        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6982        sorted_ids.sort_unstable();
6983        sorted_ids.dedup();
6984        let mut locators = SmallVec::new();
6985
6986        while sorted_ids.last() == Some(&ExcerptId::max()) {
6987            sorted_ids.pop();
6988            locators.push(Locator::max());
6989        }
6990
6991        let mut sorted_ids = sorted_ids.into_iter().peekable();
6992        locators.extend(
6993            sorted_ids
6994                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6995                .map(|_| Locator::min()),
6996        );
6997
6998        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6999        for id in sorted_ids {
7000            if cursor.seek_forward(&id, Bias::Left) {
7001                locators.push(cursor.item().unwrap().locator.clone());
7002            } else {
7003                panic!("invalid excerpt id {:?}", id);
7004            }
7005        }
7006
7007        locators.sort_unstable();
7008        locators
7009    }
7010
7011    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
7012        Some(self.excerpt(excerpt_id)?.buffer_id)
7013    }
7014
7015    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7016        Some(&self.excerpt(excerpt_id)?.buffer)
7017    }
7018
7019    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7020        let mut cursor = self
7021            .excerpts
7022            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7023        let locator = self.excerpt_locator_for_id(excerpt_id);
7024        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7025        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7026            sought_exact = true;
7027            cursor.prev();
7028        } else if excerpt_id == ExcerptId::min() {
7029            sought_exact = true;
7030        }
7031        if sought_exact {
7032            let start = cursor.start().1;
7033            let end = cursor.end().1;
7034            let mut diff_transforms = self
7035                .diff_transforms
7036                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7037            diff_transforms.seek(&start, Bias::Left);
7038            let overshoot = start - diff_transforms.start().0;
7039            let start = diff_transforms.start().1 + overshoot;
7040            diff_transforms.seek(&end, Bias::Right);
7041            let overshoot = end - diff_transforms.start().0;
7042            let end = diff_transforms.start().1 + overshoot;
7043            Some(start.0..end.0)
7044        } else {
7045            None
7046        }
7047    }
7048
7049    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7050    /// to have the latest excerpt id for the one passed in and will also remap
7051    /// `ExcerptId::max()` to the corresponding excertp ID.
7052    ///
7053    /// Callers of this function should generally use the resulting excerpt's `id` field
7054    /// afterwards.
7055    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7056        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7057        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7058        let (_, _, item) =
7059            self.excerpts
7060                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7061        if let Some(excerpt) = item
7062            && excerpt.id == excerpt_id
7063        {
7064            return Some(excerpt);
7065        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7066            return self.excerpts.last();
7067        }
7068        None
7069    }
7070
7071    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7072    pub fn excerpt_containing<T: ToOffset>(
7073        &self,
7074        range: Range<T>,
7075    ) -> Option<MultiBufferExcerpt<'_>> {
7076        let range = range.start.to_offset(self)..range.end.to_offset(self);
7077        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7078        cursor.seek(&range.start);
7079
7080        let start_excerpt = cursor.excerpt()?;
7081        if range.end != range.start {
7082            cursor.seek_forward(&range.end);
7083            if cursor.excerpt()?.id != start_excerpt.id {
7084                return None;
7085            }
7086        }
7087
7088        cursor.seek_to_start_of_current_excerpt();
7089        let region = cursor.region()?;
7090        let offset = region.range.start;
7091        let buffer_offset = start_excerpt.buffer_start_offset();
7092        let excerpt_offset = *cursor.excerpts.start();
7093        Some(MultiBufferExcerpt {
7094            diff_transforms: cursor.diff_transforms,
7095            excerpt: start_excerpt,
7096            offset,
7097            buffer_offset,
7098            excerpt_offset,
7099        })
7100    }
7101
7102    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7103        if let Some(id) = anchor.text_anchor.buffer_id {
7104            return Some(id);
7105        }
7106        let excerpt = self.excerpt_containing(anchor..anchor)?;
7107        Some(excerpt.buffer_id())
7108    }
7109
7110    pub fn selections_in_range<'a>(
7111        &'a self,
7112        range: &'a Range<Anchor>,
7113        include_local: bool,
7114    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7115        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7116        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7117        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7118        cursor.seek(start_locator, Bias::Left);
7119        cursor
7120            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7121            .flat_map(move |excerpt| {
7122                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7123                if excerpt.id == range.start.excerpt_id {
7124                    query_range.start = range.start.text_anchor;
7125                }
7126                if excerpt.id == range.end.excerpt_id {
7127                    query_range.end = range.end.text_anchor;
7128                }
7129
7130                excerpt
7131                    .buffer
7132                    .selections_in_range(query_range, include_local)
7133                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7134                        selections.map(move |selection| {
7135                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7136                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7137                            if range.start.cmp(&start, self).is_gt() {
7138                                start = range.start;
7139                            }
7140                            if range.end.cmp(&end, self).is_lt() {
7141                                end = range.end;
7142                            }
7143
7144                            (
7145                                replica_id,
7146                                line_mode,
7147                                cursor_shape,
7148                                Selection {
7149                                    id: selection.id,
7150                                    start,
7151                                    end,
7152                                    reversed: selection.reversed,
7153                                    goal: selection.goal,
7154                                },
7155                            )
7156                        })
7157                    })
7158            })
7159    }
7160
7161    pub fn show_headers(&self) -> bool {
7162        self.show_headers
7163    }
7164
7165    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7166        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7167    }
7168
7169    pub fn all_diff_hunks_expanded(&self) -> bool {
7170        self.all_diff_hunks_expanded
7171    }
7172
7173    /// Visually annotates a position or range with the `Debug` representation of a value. The
7174    /// callsite of this function is used as a key - previous annotations will be removed.
7175    #[cfg(debug_assertions)]
7176    #[track_caller]
7177    pub fn debug<V, R>(&self, ranges: &R, value: V)
7178    where
7179        R: debug::ToMultiBufferDebugRanges,
7180        V: std::fmt::Debug,
7181    {
7182        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7183    }
7184
7185    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7186    /// debug annotations with the same key will be removed. The key is also used to determine the
7187    /// annotation's color.
7188    #[cfg(debug_assertions)]
7189    #[track_caller]
7190    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7191    where
7192        K: std::hash::Hash + 'static,
7193        R: debug::ToMultiBufferDebugRanges,
7194        V: std::fmt::Debug,
7195    {
7196        let text_ranges = ranges
7197            .to_multi_buffer_debug_ranges(self)
7198            .into_iter()
7199            .flat_map(|range| {
7200                self.range_to_buffer_ranges(range.start..=range.end)
7201                    .into_iter()
7202                    .map(|(buffer, range, _excerpt_id)| {
7203                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7204                    })
7205            })
7206            .collect();
7207        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7208            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7209        });
7210    }
7211
7212    fn excerpt_edits_for_diff_change(
7213        &self,
7214        buffer_state: &BufferState,
7215        diff_change_range: Range<usize>,
7216    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7217        let mut excerpt_edits = Vec::new();
7218        for locator in &buffer_state.excerpts {
7219            let mut cursor = self
7220                .excerpts
7221                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7222            cursor.seek_forward(&Some(locator), Bias::Left);
7223            if let Some(excerpt) = cursor.item()
7224                && excerpt.locator == *locator
7225            {
7226                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7227                if diff_change_range.end < excerpt_buffer_range.start
7228                    || diff_change_range.start > excerpt_buffer_range.end
7229                {
7230                    continue;
7231                }
7232                let excerpt_start = cursor.start().1;
7233                let excerpt_len = excerpt.text_summary.len;
7234                let diff_change_start_in_excerpt = diff_change_range
7235                    .start
7236                    .saturating_sub(excerpt_buffer_range.start);
7237                let diff_change_end_in_excerpt = diff_change_range
7238                    .end
7239                    .saturating_sub(excerpt_buffer_range.start);
7240                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7241                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7242                excerpt_edits.push(Edit {
7243                    old: edit_start..edit_end,
7244                    new: edit_start..edit_end,
7245                });
7246            }
7247        }
7248        excerpt_edits
7249    }
7250}
7251
7252#[cfg(any(test, feature = "test-support"))]
7253impl MultiBufferSnapshot {
7254    pub fn random_byte_range(
7255        &self,
7256        start_offset: MultiBufferOffset,
7257        rng: &mut impl rand::Rng,
7258    ) -> Range<MultiBufferOffset> {
7259        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7260        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7261        start..end
7262    }
7263
7264    #[cfg(any(test, feature = "test-support"))]
7265    fn check_invariants(&self) {
7266        let excerpts = self.excerpts.items(());
7267        let excerpt_ids = self.excerpt_ids.items(());
7268
7269        for (ix, excerpt) in excerpts.iter().enumerate() {
7270            if ix == 0 {
7271                if excerpt.locator <= Locator::min() {
7272                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7273                }
7274            } else if excerpt.locator <= excerpts[ix - 1].locator {
7275                panic!("excerpts are out-of-order: {:?}", excerpts);
7276            }
7277        }
7278
7279        for (ix, entry) in excerpt_ids.iter().enumerate() {
7280            if ix == 0 {
7281                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7282                    panic!("invalid first excerpt id {:?}", entry.id);
7283                }
7284            } else if entry.id <= excerpt_ids[ix - 1].id {
7285                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7286            }
7287        }
7288
7289        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7290            panic!(
7291                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7292                self.excerpts.summary().text,
7293                self.diff_transforms.summary().input,
7294                self.diff_transforms.items(()),
7295            );
7296        }
7297
7298        let mut prev_transform: Option<&DiffTransform> = None;
7299        for item in self.diff_transforms.iter() {
7300            if let DiffTransform::BufferContent {
7301                summary,
7302                inserted_hunk_info,
7303            } = item
7304            {
7305                if let Some(DiffTransform::BufferContent {
7306                    inserted_hunk_info: prev_inserted_hunk_info,
7307                    ..
7308                }) = prev_transform
7309                    && *inserted_hunk_info == *prev_inserted_hunk_info
7310                {
7311                    panic!(
7312                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7313                        self.diff_transforms.items(())
7314                    );
7315                }
7316                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7317                    panic!("empty buffer content transform");
7318                }
7319            }
7320            prev_transform = Some(item);
7321        }
7322    }
7323}
7324
7325impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7326where
7327    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7328    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7329{
7330    #[instrument(skip_all)]
7331    fn seek(&mut self, position: &MBD) {
7332        let position = OutputDimension(*position);
7333        self.cached_region.take();
7334        self.diff_transforms.seek(&position, Bias::Right);
7335        if self.diff_transforms.item().is_none()
7336            && self.diff_transforms.start().output_dimension == position
7337        {
7338            self.diff_transforms.prev();
7339        }
7340
7341        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7342        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7343            let overshoot = position - self.diff_transforms.start().output_dimension;
7344            excerpt_position += overshoot;
7345        }
7346
7347        self.excerpts.seek(&excerpt_position, Bias::Right);
7348        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7349            self.excerpts.prev();
7350        }
7351    }
7352
7353    fn seek_forward(&mut self, position: &MBD) {
7354        let position = OutputDimension(*position);
7355        self.cached_region.take();
7356        self.diff_transforms.seek_forward(&position, Bias::Right);
7357        if self.diff_transforms.item().is_none()
7358            && self.diff_transforms.start().output_dimension == position
7359        {
7360            self.diff_transforms.prev();
7361        }
7362
7363        let overshoot = position - self.diff_transforms.start().output_dimension;
7364        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7365        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7366            excerpt_position += overshoot;
7367        }
7368
7369        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7370        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7371            self.excerpts.prev();
7372        }
7373    }
7374
7375    fn next_excerpt(&mut self) {
7376        self.excerpts.next();
7377        self.seek_to_start_of_current_excerpt();
7378    }
7379
7380    fn prev_excerpt(&mut self) {
7381        self.excerpts.prev();
7382        self.seek_to_start_of_current_excerpt();
7383    }
7384
7385    fn seek_to_start_of_current_excerpt(&mut self) {
7386        self.cached_region.take();
7387
7388        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7389            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7390            && self.diff_transforms.next_item().is_some()
7391        {
7392            self.diff_transforms.next();
7393        }
7394    }
7395
7396    fn next_excerpt_forwards(&mut self) {
7397        self.excerpts.next();
7398        self.seek_to_start_of_current_excerpt_forward();
7399    }
7400
7401    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7402        self.cached_region.take();
7403
7404        if self
7405            .diff_transforms
7406            .seek_forward(self.excerpts.start(), Bias::Left)
7407            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7408            && self.diff_transforms.next_item().is_some()
7409        {
7410            self.diff_transforms.next();
7411        }
7412    }
7413
7414    fn next(&mut self) {
7415        self.cached_region.take();
7416        match self
7417            .diff_transforms
7418            .end()
7419            .excerpt_dimension
7420            .cmp(&self.excerpts.end())
7421        {
7422            cmp::Ordering::Less => self.diff_transforms.next(),
7423            cmp::Ordering::Greater => self.excerpts.next(),
7424            cmp::Ordering::Equal => {
7425                self.diff_transforms.next();
7426                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7427                    || self.diff_transforms.item().is_none()
7428                {
7429                    self.excerpts.next();
7430                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7431                    self.diff_transforms.item()
7432                    && self
7433                        .excerpts
7434                        .item()
7435                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7436                {
7437                    self.excerpts.next();
7438                }
7439            }
7440        }
7441    }
7442
7443    fn prev(&mut self) {
7444        self.cached_region.take();
7445        match self
7446            .diff_transforms
7447            .start()
7448            .excerpt_dimension
7449            .cmp(self.excerpts.start())
7450        {
7451            cmp::Ordering::Less => self.excerpts.prev(),
7452            cmp::Ordering::Greater => self.diff_transforms.prev(),
7453            cmp::Ordering::Equal => {
7454                self.diff_transforms.prev();
7455                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7456                    || self.diff_transforms.item().is_none()
7457                {
7458                    self.excerpts.prev();
7459                }
7460            }
7461        }
7462    }
7463
7464    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7465        self.cached_region
7466            .get_or_init(|| self.build_region())
7467            .as_ref()
7468    }
7469
7470    fn is_at_start_of_excerpt(&mut self) -> bool {
7471        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7472            return false;
7473        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7474            return true;
7475        }
7476
7477        self.diff_transforms.prev();
7478        let prev_transform = self.diff_transforms.item();
7479        self.diff_transforms.next();
7480
7481        prev_transform.is_none_or(|next_transform| {
7482            matches!(next_transform, DiffTransform::BufferContent { .. })
7483        })
7484    }
7485
7486    fn is_at_end_of_excerpt(&self) -> bool {
7487        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7488            return false;
7489        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7490            || self.diff_transforms.item().is_none()
7491        {
7492            return true;
7493        }
7494
7495        let next_transform = self.diff_transforms.next_item();
7496        next_transform.is_none_or(|next_transform| match next_transform {
7497            DiffTransform::BufferContent { .. } => true,
7498            DiffTransform::DeletedHunk { hunk_info, .. } => self
7499                .excerpts
7500                .item()
7501                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7502        })
7503    }
7504
7505    fn main_buffer_position(&self) -> Option<BD> {
7506        let excerpt = self.excerpts.item()?;
7507        let buffer = &excerpt.buffer;
7508        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7509        let mut buffer_start = buffer_context_start;
7510        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7511        buffer_start += overshoot;
7512        Some(buffer_start)
7513    }
7514
7515    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7516        let excerpt = self.excerpts.item()?;
7517        match self.diff_transforms.item()? {
7518            DiffTransform::DeletedHunk {
7519                buffer_id,
7520                base_text_byte_range,
7521                has_trailing_newline,
7522                hunk_info,
7523                ..
7524            } => {
7525                let diff = self.diffs.get(buffer_id)?;
7526                let buffer = diff.base_text();
7527                let mut rope_cursor = buffer.as_rope().cursor(0);
7528                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7529                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7530                let mut buffer_end = buffer_start;
7531                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7532                let start = self.diff_transforms.start().output_dimension.0;
7533                let end = self.diff_transforms.end().output_dimension.0;
7534                Some(MultiBufferRegion {
7535                    buffer,
7536                    excerpt,
7537                    has_trailing_newline: *has_trailing_newline,
7538                    is_main_buffer: false,
7539                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7540                        hunk_info.hunk_secondary_status,
7541                    )),
7542                    buffer_range: buffer_start..buffer_end,
7543                    range: start..end,
7544                })
7545            }
7546            DiffTransform::BufferContent {
7547                inserted_hunk_info, ..
7548            } => {
7549                let buffer = &excerpt.buffer;
7550                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7551
7552                let mut start = self.diff_transforms.start().output_dimension.0;
7553                let mut buffer_start = buffer_context_start;
7554                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7555                    let overshoot =
7556                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7557                    start += overshoot;
7558                } else {
7559                    let overshoot =
7560                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7561                    buffer_start += overshoot;
7562                }
7563
7564                let mut end;
7565                let mut buffer_end;
7566                let has_trailing_newline;
7567                let transform_end = self.diff_transforms.end();
7568                if transform_end.excerpt_dimension < self.excerpts.end() {
7569                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7570                    end = transform_end.output_dimension.0;
7571                    buffer_end = buffer_context_start;
7572                    buffer_end += overshoot;
7573                    has_trailing_newline = false;
7574                } else {
7575                    let overshoot =
7576                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7577                    end = self.diff_transforms.start().output_dimension.0;
7578                    end += overshoot;
7579                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7580                    has_trailing_newline = excerpt.has_trailing_newline;
7581                };
7582
7583                let diff_hunk_status = inserted_hunk_info.map(|info| {
7584                    if info.is_logically_deleted {
7585                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7586                    } else {
7587                        DiffHunkStatus::added(info.hunk_secondary_status)
7588                    }
7589                });
7590
7591                Some(MultiBufferRegion {
7592                    buffer,
7593                    excerpt,
7594                    has_trailing_newline,
7595                    is_main_buffer: true,
7596                    diff_hunk_status,
7597                    buffer_range: buffer_start..buffer_end,
7598                    range: start..end,
7599                })
7600            }
7601        }
7602    }
7603
7604    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7605        let excerpt = self.excerpts.item()?;
7606        match self.diff_transforms.item()? {
7607            &DiffTransform::DeletedHunk { .. } => {
7608                let start = self.diff_transforms.start().output_dimension.0;
7609                let end = self.diff_transforms.end().output_dimension.0;
7610                Some((excerpt, start..end))
7611            }
7612            DiffTransform::BufferContent { .. } => {
7613                let mut start = self.diff_transforms.start().output_dimension.0;
7614                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7615                    let overshoot =
7616                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7617                    start += overshoot;
7618                }
7619
7620                let mut end;
7621                let transform_end = self.diff_transforms.end();
7622                if transform_end.excerpt_dimension < self.excerpts.end() {
7623                    end = transform_end.output_dimension.0;
7624                } else {
7625                    let overshoot =
7626                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7627                    end = self.diff_transforms.start().output_dimension.0;
7628                    end += overshoot;
7629                };
7630
7631                Some((excerpt, start..end))
7632            }
7633        }
7634    }
7635
7636    fn excerpt(&self) -> Option<&'a Excerpt> {
7637        self.excerpts.item()
7638    }
7639}
7640
7641impl Excerpt {
7642    fn new(
7643        id: ExcerptId,
7644        locator: Locator,
7645        buffer_id: BufferId,
7646        buffer: Arc<BufferSnapshot>,
7647        range: ExcerptRange<text::Anchor>,
7648        has_trailing_newline: bool,
7649    ) -> Self {
7650        Excerpt {
7651            id,
7652            locator,
7653            max_buffer_row: range.context.end.to_point(&buffer).row,
7654            text_summary: buffer
7655                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7656            buffer_id,
7657            buffer,
7658            range,
7659            has_trailing_newline,
7660        }
7661    }
7662
7663    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7664        let content_start = self.range.context.start.to_offset(&self.buffer);
7665        let chunks_start = content_start + range.start;
7666        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7667
7668        let has_footer = self.has_trailing_newline
7669            && range.start <= self.text_summary.len
7670            && range.end > self.text_summary.len;
7671
7672        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7673
7674        ExcerptChunks {
7675            excerpt_id: self.id,
7676            content_chunks,
7677            has_footer,
7678        }
7679    }
7680
7681    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7682        let content_start = self.range.context.start.to_offset(&self.buffer);
7683        let chunks_start = content_start + range.start;
7684        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7685        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7686        excerpt_chunks.has_footer = self.has_trailing_newline
7687            && range.start <= self.text_summary.len
7688            && range.end > self.text_summary.len;
7689    }
7690
7691    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7692        if text_anchor
7693            .cmp(&self.range.context.start, &self.buffer)
7694            .is_lt()
7695        {
7696            self.range.context.start
7697        } else if text_anchor
7698            .cmp(&self.range.context.end, &self.buffer)
7699            .is_gt()
7700        {
7701            self.range.context.end
7702        } else {
7703            text_anchor
7704        }
7705    }
7706
7707    fn contains(&self, anchor: &Anchor) -> bool {
7708        (anchor.text_anchor.buffer_id == None
7709            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7710            && self
7711                .range
7712                .context
7713                .start
7714                .cmp(&anchor.text_anchor, &self.buffer)
7715                .is_le()
7716            && self
7717                .range
7718                .context
7719                .end
7720                .cmp(&anchor.text_anchor, &self.buffer)
7721                .is_ge()
7722    }
7723
7724    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7725    fn buffer_start_offset(&self) -> BufferOffset {
7726        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7727    }
7728
7729    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7730    fn buffer_end_offset(&self) -> BufferOffset {
7731        self.buffer_start_offset() + self.text_summary.len
7732    }
7733}
7734
7735impl<'a> MultiBufferExcerpt<'a> {
7736    pub fn id(&self) -> ExcerptId {
7737        self.excerpt.id
7738    }
7739
7740    pub fn buffer_id(&self) -> BufferId {
7741        self.excerpt.buffer_id
7742    }
7743
7744    pub fn start_anchor(&self) -> Anchor {
7745        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7746    }
7747
7748    pub fn end_anchor(&self) -> Anchor {
7749        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7750    }
7751
7752    pub fn buffer(&self) -> &'a BufferSnapshot {
7753        &self.excerpt.buffer
7754    }
7755
7756    pub fn buffer_range(&self) -> Range<BufferOffset> {
7757        self.buffer_offset
7758            ..BufferOffset(
7759                self.excerpt
7760                    .range
7761                    .context
7762                    .end
7763                    .to_offset(&self.excerpt.buffer.text),
7764            )
7765    }
7766
7767    pub fn start_offset(&self) -> MultiBufferOffset {
7768        self.offset
7769    }
7770
7771    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7772    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7773        self.map_range_to_buffer(offset..offset).start
7774    }
7775
7776    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7777    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7778        self.diff_transforms
7779            .seek(&OutputDimension(range.start), Bias::Right);
7780        let start = self.map_offset_to_buffer_internal(range.start);
7781        let end = if range.end > range.start {
7782            self.diff_transforms
7783                .seek_forward(&OutputDimension(range.end), Bias::Right);
7784            self.map_offset_to_buffer_internal(range.end)
7785        } else {
7786            start
7787        };
7788        start..end
7789    }
7790
7791    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7792        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7793        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7794            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7795        };
7796        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7797        self.buffer_offset + offset_in_excerpt
7798    }
7799
7800    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7801    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7802        self.map_range_from_buffer(buffer_offset..buffer_offset)
7803            .start
7804    }
7805
7806    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7807    pub fn map_range_from_buffer(
7808        &mut self,
7809        buffer_range: Range<BufferOffset>,
7810    ) -> Range<MultiBufferOffset> {
7811        if buffer_range.start < self.buffer_offset {
7812            log::warn!(
7813                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7814            );
7815            return self.offset..self.offset;
7816        }
7817        let overshoot = buffer_range.start - self.buffer_offset;
7818        let excerpt_offset = self.excerpt_offset + overshoot;
7819        let excerpt_seek_dim = excerpt_offset;
7820        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7821        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7822            log::warn!(
7823                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7824            );
7825            return self.offset..self.offset;
7826        }
7827        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7828        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7829
7830        let end = if buffer_range.start < buffer_range.end {
7831            let overshoot = buffer_range.end - self.buffer_offset;
7832            let excerpt_offset = self.excerpt_offset + overshoot;
7833            let excerpt_seek_dim = excerpt_offset;
7834            self.diff_transforms
7835                .seek_forward(&excerpt_seek_dim, Bias::Right);
7836            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7837            // todo(lw): Clamp end to the excerpt boundaries
7838            self.diff_transforms.start().output_dimension.0 + overshoot
7839        } else {
7840            start
7841        };
7842
7843        start..end
7844    }
7845
7846    /// Returns true if the entirety of the given range is in the buffer's excerpt
7847    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7848        range.start >= self.excerpt.buffer_start_offset()
7849            && range.end <= self.excerpt.buffer_end_offset()
7850    }
7851
7852    /// Returns true if any part of the given range is in the buffer's excerpt
7853    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7854        range.start <= self.excerpt.buffer_end_offset()
7855            && range.end >= self.excerpt.buffer_start_offset()
7856    }
7857
7858    pub fn max_buffer_row(&self) -> u32 {
7859        self.excerpt.max_buffer_row
7860    }
7861}
7862
7863impl ExcerptId {
7864    pub fn min() -> Self {
7865        Self(0)
7866    }
7867
7868    pub fn max() -> Self {
7869        Self(u32::MAX)
7870    }
7871
7872    pub fn to_proto(self) -> u64 {
7873        self.0 as _
7874    }
7875
7876    pub fn from_proto(proto: u64) -> Self {
7877        Self(proto as _)
7878    }
7879
7880    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7881        let a = snapshot.excerpt_locator_for_id(*self);
7882        let b = snapshot.excerpt_locator_for_id(*other);
7883        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7884    }
7885}
7886
7887impl From<ExcerptId> for usize {
7888    fn from(val: ExcerptId) -> Self {
7889        val.0 as usize
7890    }
7891}
7892
7893impl fmt::Debug for Excerpt {
7894    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7895        f.debug_struct("Excerpt")
7896            .field("id", &self.id)
7897            .field("locator", &self.locator)
7898            .field("buffer_id", &self.buffer_id)
7899            .field("range", &self.range)
7900            .field("text_summary", &self.text_summary)
7901            .field("has_trailing_newline", &self.has_trailing_newline)
7902            .finish()
7903    }
7904}
7905
7906impl sum_tree::Item for Excerpt {
7907    type Summary = ExcerptSummary;
7908
7909    fn summary(&self, _cx: ()) -> Self::Summary {
7910        let mut text = self.text_summary;
7911        if self.has_trailing_newline {
7912            text += TextSummary::from("\n");
7913        }
7914        ExcerptSummary {
7915            excerpt_id: self.id,
7916            excerpt_locator: self.locator.clone(),
7917            widest_line_number: self.max_buffer_row,
7918            text: text.into(),
7919            count: 1,
7920        }
7921    }
7922}
7923
7924impl sum_tree::Item for ExcerptIdMapping {
7925    type Summary = ExcerptId;
7926
7927    fn summary(&self, _cx: ()) -> Self::Summary {
7928        self.id
7929    }
7930}
7931
7932impl sum_tree::KeyedItem for ExcerptIdMapping {
7933    type Key = ExcerptId;
7934
7935    fn key(&self) -> Self::Key {
7936        self.id
7937    }
7938}
7939
7940impl DiffTransform {
7941    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7942        match self {
7943            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7944            DiffTransform::BufferContent {
7945                inserted_hunk_info, ..
7946            } => *inserted_hunk_info,
7947        }
7948    }
7949}
7950
7951impl sum_tree::Item for DiffTransform {
7952    type Summary = DiffTransformSummary;
7953
7954    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7955        match self {
7956            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7957                input: *summary,
7958                output: *summary,
7959            },
7960            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7961                input: MBTextSummary::default(),
7962                output: summary.into(),
7963            },
7964        }
7965    }
7966}
7967
7968impl DiffTransformSummary {
7969    fn excerpt_len(&self) -> ExcerptOffset {
7970        ExcerptDimension(self.input.len)
7971    }
7972}
7973
7974impl sum_tree::ContextLessSummary for DiffTransformSummary {
7975    fn zero() -> Self {
7976        DiffTransformSummary {
7977            input: MBTextSummary::default(),
7978            output: MBTextSummary::default(),
7979        }
7980    }
7981
7982    fn add_summary(&mut self, other: &Self) {
7983        self.input += other.input;
7984        self.output += other.output;
7985    }
7986}
7987
7988impl sum_tree::ContextLessSummary for ExcerptId {
7989    fn zero() -> Self {
7990        Self(0)
7991    }
7992
7993    fn add_summary(&mut self, summary: &Self) {
7994        *self = cmp::max(*self, *summary);
7995    }
7996}
7997
7998impl sum_tree::ContextLessSummary for ExcerptSummary {
7999    fn zero() -> Self {
8000        Self::default()
8001    }
8002
8003    fn add_summary(&mut self, summary: &Self) {
8004        debug_assert!(
8005            summary.excerpt_locator > self.excerpt_locator
8006                || self.excerpt_locator == Locator::min(),
8007            "Excerpt locators must be in ascending order: {:?} > {:?}",
8008            summary.excerpt_locator,
8009            self.excerpt_locator
8010        );
8011        self.excerpt_locator = summary.excerpt_locator.clone();
8012        self.text += summary.text;
8013        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
8014        self.count += summary.count;
8015    }
8016}
8017
8018impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8019    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8020        Ord::cmp(&Some(self), cursor_location)
8021    }
8022}
8023
8024impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8025    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8026        Ord::cmp(self, &cursor_location.excerpt_locator)
8027    }
8028}
8029
8030impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8031where
8032    MBD: MultiBufferDimension + Default,
8033{
8034    fn zero(_: ()) -> Self {
8035        ExcerptDimension(MBD::default())
8036    }
8037
8038    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8039        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8040    }
8041}
8042
8043impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8044    fn zero(_cx: ()) -> Self {
8045        Default::default()
8046    }
8047
8048    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8049        *self = Some(&summary.excerpt_locator);
8050    }
8051}
8052
8053impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8054    fn zero(_cx: ()) -> Self {
8055        Default::default()
8056    }
8057
8058    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8059        *self = Some(summary.excerpt_id);
8060    }
8061}
8062
8063#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8064struct OutputDimension<T>(T);
8065
8066impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8067    fn eq(&self, other: &T) -> bool {
8068        self.0 == *other
8069    }
8070}
8071
8072impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8073    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8074        self.0.partial_cmp(other)
8075    }
8076}
8077
8078impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8079where
8080    T: ops::Sub<U, Output = R>,
8081{
8082    type Output = R;
8083
8084    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8085        self.0 - other.0
8086    }
8087}
8088
8089impl<R, T, U> ops::Add<U> for OutputDimension<T>
8090where
8091    T: ops::Add<U, Output = R>,
8092{
8093    type Output = OutputDimension<R>;
8094
8095    fn add(self, other: U) -> Self::Output {
8096        OutputDimension(self.0 + other)
8097    }
8098}
8099
8100impl<T, U> AddAssign<U> for OutputDimension<T>
8101where
8102    T: AddAssign<U>,
8103{
8104    fn add_assign(&mut self, other: U) {
8105        self.0 += other;
8106    }
8107}
8108
8109impl<T, U> SubAssign<U> for OutputDimension<T>
8110where
8111    T: SubAssign<U>,
8112{
8113    fn sub_assign(&mut self, other: U) {
8114        self.0 -= other;
8115    }
8116}
8117
8118#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8119struct ExcerptDimension<T>(T);
8120
8121impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8122    fn eq(&self, other: &T) -> bool {
8123        self.0 == *other
8124    }
8125}
8126
8127impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8128    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8129        self.0.partial_cmp(other)
8130    }
8131}
8132
8133impl ExcerptOffset {
8134    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8135        self.0.saturating_sub(other.0)
8136    }
8137}
8138
8139impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8140where
8141    T: ops::Sub<U, Output = R>,
8142{
8143    type Output = R;
8144
8145    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8146        self.0 - other.0
8147    }
8148}
8149
8150impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8151where
8152    T: ops::Add<U, Output = R>,
8153{
8154    type Output = ExcerptDimension<R>;
8155
8156    fn add(self, other: U) -> Self::Output {
8157        ExcerptDimension(self.0 + other)
8158    }
8159}
8160
8161impl<T, U> AddAssign<U> for ExcerptDimension<T>
8162where
8163    T: AddAssign<U>,
8164{
8165    fn add_assign(&mut self, other: U) {
8166        self.0 += other;
8167    }
8168}
8169
8170impl<T, U> SubAssign<U> for ExcerptDimension<T>
8171where
8172    T: SubAssign<U>,
8173{
8174    fn sub_assign(&mut self, other: U) {
8175        self.0 -= other;
8176    }
8177}
8178
8179impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8180    fn zero(_: ()) -> Self {
8181        MultiBufferOffset::ZERO
8182    }
8183
8184    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8185        *self += summary.output.len;
8186    }
8187}
8188
8189impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8190    for ExcerptDimension<MBD>
8191where
8192    MBD: MultiBufferDimension + Ord,
8193{
8194    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8195        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8196    }
8197}
8198
8199impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8200    for ExcerptDimension<MBD>
8201where
8202    MBD: MultiBufferDimension + Ord,
8203{
8204    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8205        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8206    }
8207}
8208
8209impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8210    for ExcerptDimension<MBD>
8211{
8212    fn zero(_: ()) -> Self {
8213        ExcerptDimension(MBD::default())
8214    }
8215
8216    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8217        self.0.add_mb_text_summary(&summary.input)
8218    }
8219}
8220
8221impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8222    for OutputDimension<MBD>
8223where
8224    MBD: MultiBufferDimension + Ord,
8225{
8226    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8227        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8228    }
8229}
8230
8231impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8232    for OutputDimension<MBD>
8233{
8234    fn zero(_: ()) -> Self {
8235        OutputDimension(MBD::default())
8236    }
8237
8238    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8239        self.0.add_mb_text_summary(&summary.output)
8240    }
8241}
8242
8243impl MultiBufferRows<'_> {
8244    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8245        self.point = Point::new(row, 0);
8246        self.cursor.seek(&self.point);
8247    }
8248}
8249
8250impl Iterator for MultiBufferRows<'_> {
8251    type Item = RowInfo;
8252
8253    fn next(&mut self) -> Option<Self::Item> {
8254        if self.is_empty && self.point.row == 0 {
8255            self.point += Point::new(1, 0);
8256            return Some(RowInfo {
8257                buffer_id: None,
8258                buffer_row: Some(0),
8259                multibuffer_row: Some(MultiBufferRow(0)),
8260                diff_status: None,
8261                expand_info: None,
8262                wrapped_buffer_row: None,
8263            });
8264        }
8265
8266        let mut region = self.cursor.region()?.clone();
8267        while self.point >= region.range.end {
8268            self.cursor.next();
8269            if let Some(next_region) = self.cursor.region() {
8270                region = next_region.clone();
8271            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8272                let multibuffer_row = MultiBufferRow(self.point.row);
8273                let last_excerpt = self
8274                    .cursor
8275                    .excerpts
8276                    .item()
8277                    .or(self.cursor.excerpts.prev_item())?;
8278                let last_row = last_excerpt
8279                    .range
8280                    .context
8281                    .end
8282                    .to_point(&last_excerpt.buffer)
8283                    .row;
8284
8285                let first_row = last_excerpt
8286                    .range
8287                    .context
8288                    .start
8289                    .to_point(&last_excerpt.buffer)
8290                    .row;
8291
8292                let expand_info = if self.is_singleton {
8293                    None
8294                } else {
8295                    let needs_expand_up = first_row == last_row
8296                        && last_row > 0
8297                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8298                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8299
8300                    if needs_expand_up && needs_expand_down {
8301                        Some(ExpandExcerptDirection::UpAndDown)
8302                    } else if needs_expand_up {
8303                        Some(ExpandExcerptDirection::Up)
8304                    } else if needs_expand_down {
8305                        Some(ExpandExcerptDirection::Down)
8306                    } else {
8307                        None
8308                    }
8309                    .map(|direction| ExpandInfo {
8310                        direction,
8311                        excerpt_id: last_excerpt.id,
8312                    })
8313                };
8314                self.point += Point::new(1, 0);
8315                return Some(RowInfo {
8316                    buffer_id: Some(last_excerpt.buffer_id),
8317                    buffer_row: Some(last_row),
8318                    multibuffer_row: Some(multibuffer_row),
8319                    diff_status: None,
8320                    wrapped_buffer_row: None,
8321                    expand_info,
8322                });
8323            } else {
8324                return None;
8325            };
8326        }
8327
8328        let overshoot = self.point - region.range.start;
8329        let buffer_point = region.buffer_range.start + overshoot;
8330        let expand_info = if self.is_singleton {
8331            None
8332        } else {
8333            let needs_expand_up = self.point.row == region.range.start.row
8334                && self.cursor.is_at_start_of_excerpt()
8335                && buffer_point.row > 0;
8336            let needs_expand_down = (region.excerpt.has_trailing_newline
8337                && self.point.row + 1 == region.range.end.row
8338                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8339                && self.cursor.is_at_end_of_excerpt()
8340                && buffer_point.row < region.buffer.max_point().row;
8341
8342            if needs_expand_up && needs_expand_down {
8343                Some(ExpandExcerptDirection::UpAndDown)
8344            } else if needs_expand_up {
8345                Some(ExpandExcerptDirection::Up)
8346            } else if needs_expand_down {
8347                Some(ExpandExcerptDirection::Down)
8348            } else {
8349                None
8350            }
8351            .map(|direction| ExpandInfo {
8352                direction,
8353                excerpt_id: region.excerpt.id,
8354            })
8355        };
8356
8357        let result = Some(RowInfo {
8358            buffer_id: Some(region.buffer.remote_id()),
8359            buffer_row: Some(buffer_point.row),
8360            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8361            diff_status: region
8362                .diff_hunk_status
8363                .filter(|_| self.point < region.range.end),
8364            expand_info,
8365            wrapped_buffer_row: None,
8366        });
8367        self.point += Point::new(1, 0);
8368        result
8369    }
8370}
8371
8372impl<'a> MultiBufferChunks<'a> {
8373    pub fn offset(&self) -> MultiBufferOffset {
8374        self.range.start
8375    }
8376
8377    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8378        self.diff_transforms.seek(&range.end, Bias::Right);
8379        let mut excerpt_end = self.diff_transforms.start().1;
8380        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8381            let overshoot = range.end - self.diff_transforms.start().0;
8382            excerpt_end += overshoot;
8383        }
8384
8385        self.diff_transforms.seek(&range.start, Bias::Right);
8386        let mut excerpt_start = self.diff_transforms.start().1;
8387        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8388            let overshoot = range.start - self.diff_transforms.start().0;
8389            excerpt_start += overshoot;
8390        }
8391
8392        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8393        self.buffer_chunk.take();
8394        self.range = range;
8395    }
8396
8397    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8398        self.excerpt_offset_range = new_range.clone();
8399        self.excerpts.seek(&new_range.start, Bias::Right);
8400        if let Some(excerpt) = self.excerpts.item() {
8401            let excerpt_start = *self.excerpts.start();
8402            if let Some(excerpt_chunks) = self
8403                .excerpt_chunks
8404                .as_mut()
8405                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8406            {
8407                excerpt.seek_chunks(
8408                    excerpt_chunks,
8409                    (self.excerpt_offset_range.start - excerpt_start)
8410                        ..(self.excerpt_offset_range.end - excerpt_start),
8411                );
8412            } else {
8413                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8414                    (self.excerpt_offset_range.start - excerpt_start)
8415                        ..(self.excerpt_offset_range.end - excerpt_start),
8416                    self.language_aware,
8417                ));
8418            }
8419        } else {
8420            self.excerpt_chunks = None;
8421        }
8422    }
8423
8424    #[ztracing::instrument(skip_all)]
8425    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8426        loop {
8427            if self.excerpt_offset_range.is_empty() {
8428                return None;
8429            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8430                self.excerpt_offset_range.start += chunk.text.len();
8431                return Some(chunk);
8432            } else {
8433                self.excerpts.next();
8434                let excerpt = self.excerpts.item()?;
8435                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8436                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8437                    self.language_aware,
8438                ));
8439            }
8440        }
8441    }
8442}
8443
8444impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8445    type Item = &'a str;
8446
8447    fn next(&mut self) -> Option<Self::Item> {
8448        let mut region = self.cursor.region()?;
8449        if self.offset == region.range.start {
8450            self.cursor.prev();
8451            region = self.cursor.region()?;
8452            let start_overshoot = self.start.saturating_sub(region.range.start);
8453            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8454                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8455            ));
8456        }
8457
8458        if self.offset == region.range.end && region.has_trailing_newline {
8459            self.offset -= 1;
8460            Some("\n")
8461        } else {
8462            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8463            self.offset -= chunk.len();
8464            Some(chunk)
8465        }
8466    }
8467}
8468
8469impl<'a> Iterator for MultiBufferChunks<'a> {
8470    type Item = Chunk<'a>;
8471
8472    #[ztracing::instrument(skip_all)]
8473    fn next(&mut self) -> Option<Chunk<'a>> {
8474        if self.range.start >= self.range.end {
8475            return None;
8476        }
8477        if self.range.start == self.diff_transforms.end().0 {
8478            self.diff_transforms.next();
8479        }
8480
8481        let diff_transform_start = self.diff_transforms.start().0;
8482        let diff_transform_end = self.diff_transforms.end().0;
8483        debug_assert!(
8484            self.range.start < diff_transform_end,
8485            "{:?} < {:?} of ({1:?}..{2:?})",
8486            self.range.start,
8487            diff_transform_end,
8488            diff_transform_start
8489        );
8490
8491        let diff_transform = self.diff_transforms.item()?;
8492        match diff_transform {
8493            DiffTransform::BufferContent { .. } => {
8494                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8495                    chunk
8496                } else {
8497                    let chunk = self.next_excerpt_chunk().unwrap();
8498                    self.buffer_chunk.insert(chunk)
8499                };
8500
8501                let chunk_end = self.range.start + chunk.text.len();
8502                let diff_transform_end = diff_transform_end.min(self.range.end);
8503
8504                if diff_transform_end < chunk_end {
8505                    let split_idx = diff_transform_end - self.range.start;
8506                    let (before, after) = chunk.text.split_at(split_idx);
8507                    self.range.start = diff_transform_end;
8508                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8509                    let chars = chunk.chars & mask;
8510                    let tabs = chunk.tabs & mask;
8511                    let newlines = chunk.newlines & mask;
8512
8513                    chunk.text = after;
8514                    chunk.chars = chunk.chars >> split_idx;
8515                    chunk.tabs = chunk.tabs >> split_idx;
8516                    chunk.newlines = chunk.newlines >> split_idx;
8517
8518                    Some(Chunk {
8519                        text: before,
8520                        chars,
8521                        tabs,
8522                        newlines,
8523                        ..chunk.clone()
8524                    })
8525                } else {
8526                    self.range.start = chunk_end;
8527                    self.buffer_chunk.take()
8528                }
8529            }
8530            DiffTransform::DeletedHunk {
8531                buffer_id,
8532                base_text_byte_range,
8533                has_trailing_newline,
8534                ..
8535            } => {
8536                let base_text_start =
8537                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8538                let base_text_end =
8539                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8540                let base_text_end = base_text_end.min(base_text_byte_range.end);
8541
8542                let mut chunks = if let Some((_, mut chunks)) = self
8543                    .diff_base_chunks
8544                    .take()
8545                    .filter(|(id, _)| id == buffer_id)
8546                {
8547                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8548                    {
8549                        chunks.seek(base_text_start..base_text_end);
8550                    }
8551                    chunks
8552                } else {
8553                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8554                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8555                };
8556
8557                let chunk = if let Some(chunk) = chunks.next() {
8558                    self.range.start += chunk.text.len();
8559                    self.diff_base_chunks = Some((*buffer_id, chunks));
8560                    chunk
8561                } else {
8562                    debug_assert!(has_trailing_newline);
8563                    self.range.start += "\n".len();
8564                    Chunk {
8565                        text: "\n",
8566                        chars: 1u128,
8567                        newlines: 1u128,
8568                        ..Default::default()
8569                    }
8570                };
8571                Some(chunk)
8572            }
8573        }
8574    }
8575}
8576
8577impl MultiBufferBytes<'_> {
8578    fn consume(&mut self, len: usize) {
8579        self.range.start += len;
8580        self.chunk = &self.chunk[len..];
8581
8582        if !self.range.is_empty() && self.chunk.is_empty() {
8583            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8584                self.chunk = chunk;
8585            } else if self.has_trailing_newline {
8586                self.has_trailing_newline = false;
8587                self.chunk = b"\n";
8588            } else {
8589                self.cursor.next();
8590                if let Some(region) = self.cursor.region() {
8591                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8592                        region.buffer_range.start
8593                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8594                                .min(region.buffer_range.end),
8595                    );
8596                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8597                    self.excerpt_bytes = Some(excerpt_bytes);
8598                    self.has_trailing_newline =
8599                        region.has_trailing_newline && self.range.end >= region.range.end;
8600                    if self.chunk.is_empty() && self.has_trailing_newline {
8601                        self.has_trailing_newline = false;
8602                        self.chunk = b"\n";
8603                    }
8604                }
8605            }
8606        }
8607    }
8608}
8609
8610impl<'a> Iterator for MultiBufferBytes<'a> {
8611    type Item = &'a [u8];
8612
8613    fn next(&mut self) -> Option<Self::Item> {
8614        let chunk = self.chunk;
8615        if chunk.is_empty() {
8616            None
8617        } else {
8618            self.consume(chunk.len());
8619            Some(chunk)
8620        }
8621    }
8622}
8623
8624impl io::Read for MultiBufferBytes<'_> {
8625    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8626        let len = cmp::min(buf.len(), self.chunk.len());
8627        buf[..len].copy_from_slice(&self.chunk[..len]);
8628        if len > 0 {
8629            self.consume(len);
8630        }
8631        Ok(len)
8632    }
8633}
8634
8635impl io::Read for ReversedMultiBufferBytes<'_> {
8636    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8637        let len = cmp::min(buf.len(), self.chunk.len());
8638        buf[..len].copy_from_slice(&self.chunk[..len]);
8639        buf[..len].reverse();
8640        if len > 0 {
8641            self.range.end -= len;
8642            self.chunk = &self.chunk[..self.chunk.len() - len];
8643            if !self.range.is_empty()
8644                && self.chunk.is_empty()
8645                && let Some(chunk) = self.chunks.next()
8646            {
8647                self.chunk = chunk.as_bytes();
8648            }
8649        }
8650        Ok(len)
8651    }
8652}
8653
8654impl<'a> Iterator for ExcerptChunks<'a> {
8655    type Item = Chunk<'a>;
8656
8657    fn next(&mut self) -> Option<Self::Item> {
8658        if let Some(chunk) = self.content_chunks.next() {
8659            return Some(chunk);
8660        }
8661
8662        if self.has_footer {
8663            let text = "\n";
8664            let chars = 0b1;
8665            let newlines = 0b1;
8666            self.has_footer = false;
8667            return Some(Chunk {
8668                text,
8669                chars,
8670                newlines,
8671                ..Default::default()
8672            });
8673        }
8674
8675        None
8676    }
8677}
8678
8679impl ToOffset for Point {
8680    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8681        snapshot.point_to_offset(*self)
8682    }
8683    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8684        snapshot.point_to_offset_utf16(*self)
8685    }
8686}
8687
8688impl ToOffset for MultiBufferOffset {
8689    #[track_caller]
8690    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8691        assert!(
8692            *self <= snapshot.len(),
8693            "offset {} is greater than the snapshot.len() {}",
8694            self.0,
8695            snapshot.len().0,
8696        );
8697        *self
8698    }
8699    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8700        snapshot.offset_to_offset_utf16(*self)
8701    }
8702}
8703
8704impl ToOffset for MultiBufferOffsetUtf16 {
8705    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8706        snapshot.offset_utf16_to_offset(*self)
8707    }
8708
8709    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8710        *self
8711    }
8712}
8713
8714impl ToOffset for PointUtf16 {
8715    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8716        snapshot.point_utf16_to_offset(*self)
8717    }
8718    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8719        snapshot.point_utf16_to_offset_utf16(*self)
8720    }
8721}
8722
8723impl ToPoint for MultiBufferOffset {
8724    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8725        snapshot.offset_to_point(*self)
8726    }
8727    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8728        snapshot.offset_to_point_utf16(*self)
8729    }
8730}
8731
8732impl ToPoint for Point {
8733    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8734        *self
8735    }
8736    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8737        snapshot.point_to_point_utf16(*self)
8738    }
8739}
8740
8741impl ToPoint for PointUtf16 {
8742    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8743        snapshot.point_utf16_to_point(*self)
8744    }
8745    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8746        *self
8747    }
8748}
8749
8750impl From<ExcerptId> for EntityId {
8751    fn from(id: ExcerptId) -> Self {
8752        EntityId::from(id.0 as u64)
8753    }
8754}
8755
8756#[cfg(debug_assertions)]
8757pub mod debug {
8758    use super::*;
8759
8760    pub trait ToMultiBufferDebugRanges {
8761        fn to_multi_buffer_debug_ranges(
8762            &self,
8763            snapshot: &MultiBufferSnapshot,
8764        ) -> Vec<Range<MultiBufferOffset>>;
8765    }
8766
8767    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8768        fn to_multi_buffer_debug_ranges(
8769            &self,
8770            snapshot: &MultiBufferSnapshot,
8771        ) -> Vec<Range<MultiBufferOffset>> {
8772            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8773        }
8774    }
8775
8776    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8777        fn to_multi_buffer_debug_ranges(
8778            &self,
8779            snapshot: &MultiBufferSnapshot,
8780        ) -> Vec<Range<MultiBufferOffset>> {
8781            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8782                .to_multi_buffer_debug_ranges(snapshot)
8783        }
8784    }
8785
8786    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8787        fn to_multi_buffer_debug_ranges(
8788            &self,
8789            snapshot: &MultiBufferSnapshot,
8790        ) -> Vec<Range<MultiBufferOffset>> {
8791            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8792        }
8793    }
8794
8795    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8796        fn to_multi_buffer_debug_ranges(
8797            &self,
8798            snapshot: &MultiBufferSnapshot,
8799        ) -> Vec<Range<MultiBufferOffset>> {
8800            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8801        }
8802    }
8803
8804    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8805        fn to_multi_buffer_debug_ranges(
8806            &self,
8807            snapshot: &MultiBufferSnapshot,
8808        ) -> Vec<Range<MultiBufferOffset>> {
8809            self.iter()
8810                .map(|item| {
8811                    let offset = item.to_offset(snapshot);
8812                    offset..offset
8813                })
8814                .collect()
8815        }
8816    }
8817
8818    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8819        fn to_multi_buffer_debug_ranges(
8820            &self,
8821            snapshot: &MultiBufferSnapshot,
8822        ) -> Vec<Range<MultiBufferOffset>> {
8823            self.iter()
8824                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8825                .collect()
8826        }
8827    }
8828}