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        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    main_buffer: Option<Entity<language::Buffer>>,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    main_buffer: Option<language::BufferSnapshot>,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            main_buffer: None,
 577        }
 578    }
 579
 580    fn new_inverted(
 581        diff: Entity<BufferDiff>,
 582        main_buffer: Entity<language::Buffer>,
 583        cx: &mut Context<MultiBuffer>,
 584    ) -> Self {
 585        let weak_main_buffer = main_buffer.downgrade();
 586        DiffState {
 587            _subscription: cx.subscribe(&diff, {
 588                move |this, diff, event, cx| {
 589                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 590                        return;
 591                    };
 592                    match event {
 593                        BufferDiffEvent::DiffChanged(DiffChanged {
 594                            changed_range: _,
 595                            base_text_changed_range,
 596                            extended_range: _,
 597                        }) => {
 598                            this.inverted_buffer_diff_changed(
 599                                diff,
 600                                main_buffer,
 601                                base_text_changed_range.clone(),
 602                                cx,
 603                            );
 604                            cx.emit(Event::BufferDiffChanged);
 605                        }
 606                        BufferDiffEvent::LanguageChanged => {
 607                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 608                        }
 609                        _ => {}
 610                    }
 611                }
 612            }),
 613            diff,
 614            main_buffer: Some(main_buffer),
 615        }
 616    }
 617}
 618
 619/// The contents of a [`MultiBuffer`] at a single point in time.
 620#[derive(Clone, Default)]
 621pub struct MultiBufferSnapshot {
 622    excerpts: SumTree<Excerpt>,
 623    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 624    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 625    diff_transforms: SumTree<DiffTransform>,
 626    excerpt_ids: SumTree<ExcerptIdMapping>,
 627    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 628    non_text_state_update_count: usize,
 629    edit_count: usize,
 630    is_dirty: bool,
 631    has_deleted_file: bool,
 632    has_conflict: bool,
 633    has_inverted_diff: bool,
 634    singleton: bool,
 635    trailing_excerpt_update_count: usize,
 636    all_diff_hunks_expanded: bool,
 637    show_deleted_hunks: bool,
 638    use_extended_diff_range: bool,
 639    show_headers: bool,
 640}
 641
 642// follower: None
 643// - BufferContent(Some)
 644// - BufferContent(None)
 645// - DeletedHunk
 646//
 647// follower: Some
 648// - BufferContent(Some)
 649// - BufferContent(None)
 650
 651#[derive(Debug, Clone)]
 652enum DiffTransform {
 653    // RealText
 654    BufferContent {
 655        summary: MBTextSummary,
 656        // modified_hunk_info
 657        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 658    },
 659    // ExpandedHunkText
 660    DeletedHunk {
 661        summary: TextSummary,
 662        buffer_id: BufferId,
 663        hunk_info: DiffTransformHunkInfo,
 664        base_text_byte_range: Range<usize>,
 665        has_trailing_newline: bool,
 666    },
 667}
 668
 669#[derive(Clone, Copy, Debug)]
 670struct DiffTransformHunkInfo {
 671    excerpt_id: ExcerptId,
 672    hunk_start_anchor: text::Anchor,
 673    hunk_secondary_status: DiffHunkSecondaryStatus,
 674    is_logically_deleted: bool,
 675}
 676
 677impl Eq for DiffTransformHunkInfo {}
 678
 679impl PartialEq for DiffTransformHunkInfo {
 680    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 681        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 682    }
 683}
 684
 685impl std::hash::Hash for DiffTransformHunkInfo {
 686    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 687        self.excerpt_id.hash(state);
 688        self.hunk_start_anchor.hash(state);
 689    }
 690}
 691
 692#[derive(Clone)]
 693pub struct ExcerptInfo {
 694    pub id: ExcerptId,
 695    pub buffer: Arc<BufferSnapshot>,
 696    pub buffer_id: BufferId,
 697    pub range: ExcerptRange<text::Anchor>,
 698    pub end_row: MultiBufferRow,
 699}
 700
 701impl std::fmt::Debug for ExcerptInfo {
 702    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 703        f.debug_struct(type_name::<Self>())
 704            .field("id", &self.id)
 705            .field("buffer_id", &self.buffer_id)
 706            .field("path", &self.buffer.file().map(|f| f.path()))
 707            .field("range", &self.range)
 708            .finish()
 709    }
 710}
 711
 712/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 713#[derive(Debug)]
 714pub struct ExcerptBoundary {
 715    pub prev: Option<ExcerptInfo>,
 716    pub next: ExcerptInfo,
 717    /// The row in the `MultiBuffer` where the boundary is located
 718    pub row: MultiBufferRow,
 719}
 720
 721impl ExcerptBoundary {
 722    pub fn starts_new_buffer(&self) -> bool {
 723        match (self.prev.as_ref(), &self.next) {
 724            (None, _) => true,
 725            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 726        }
 727    }
 728}
 729
 730#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 731pub struct ExpandInfo {
 732    pub direction: ExpandExcerptDirection,
 733    pub excerpt_id: ExcerptId,
 734}
 735
 736#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 737pub struct RowInfo {
 738    pub buffer_id: Option<BufferId>,
 739    pub buffer_row: Option<u32>,
 740    pub multibuffer_row: Option<MultiBufferRow>,
 741    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 742    pub expand_info: Option<ExpandInfo>,
 743    pub wrapped_buffer_row: Option<u32>,
 744}
 745
 746/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 747#[derive(Clone)]
 748struct Excerpt {
 749    /// The unique identifier for this excerpt
 750    id: ExcerptId,
 751    /// The location of the excerpt in the [`MultiBuffer`]
 752    locator: Locator,
 753    /// The buffer being excerpted
 754    buffer_id: BufferId,
 755    /// A snapshot of the buffer being excerpted
 756    buffer: Arc<BufferSnapshot>,
 757    /// The range of the buffer to be shown in the excerpt
 758    range: ExcerptRange<text::Anchor>,
 759    /// The last row in the excerpted slice of the buffer
 760    max_buffer_row: BufferRow,
 761    /// A summary of the text in the excerpt
 762    text_summary: TextSummary,
 763    has_trailing_newline: bool,
 764}
 765
 766/// A public view into an `Excerpt` in a [`MultiBuffer`].
 767///
 768/// Contains methods for getting the [`Buffer`] of the excerpt,
 769/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 770#[derive(Clone)]
 771pub struct MultiBufferExcerpt<'a> {
 772    excerpt: &'a Excerpt,
 773    diff_transforms:
 774        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 775    /// The offset in the multibuffer considering diff transforms.
 776    offset: MultiBufferOffset,
 777    /// The offset in the multibuffer without diff transforms.
 778    excerpt_offset: ExcerptOffset,
 779    buffer_offset: BufferOffset,
 780}
 781
 782#[derive(Clone, Debug)]
 783struct ExcerptIdMapping {
 784    id: ExcerptId,
 785    locator: Locator,
 786}
 787
 788/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 789/// These ranges are relative to the buffer itself
 790#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 791pub struct ExcerptRange<T> {
 792    /// The full range of text to be shown in the excerpt.
 793    pub context: Range<T>,
 794    /// The primary range of text to be highlighted in the excerpt.
 795    /// In a multi-buffer search, this would be the text that matched the search
 796    pub primary: Range<T>,
 797}
 798
 799impl<T: Clone> ExcerptRange<T> {
 800    pub fn new(context: Range<T>) -> Self {
 801        Self {
 802            context: context.clone(),
 803            primary: context,
 804        }
 805    }
 806}
 807
 808#[derive(Clone, Debug, Default)]
 809pub struct ExcerptSummary {
 810    excerpt_id: ExcerptId,
 811    /// The location of the last [`Excerpt`] being summarized
 812    excerpt_locator: Locator,
 813    widest_line_number: u32,
 814    text: MBTextSummary,
 815    count: usize,
 816}
 817
 818#[derive(Debug, Clone)]
 819pub struct DiffTransformSummary {
 820    input: MBTextSummary,
 821    output: MBTextSummary,
 822}
 823
 824/// Summary of a string of text.
 825#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 826pub struct MBTextSummary {
 827    /// Length in bytes.
 828    pub len: MultiBufferOffset,
 829    /// Length in UTF-8.
 830    pub chars: usize,
 831    /// Length in UTF-16 code units
 832    pub len_utf16: OffsetUtf16,
 833    /// A point representing the number of lines and the length of the last line.
 834    ///
 835    /// In other words, it marks the point after the last byte in the text, (if
 836    /// EOF was a character, this would be its position).
 837    pub lines: Point,
 838    /// How many `char`s are in the first line
 839    pub first_line_chars: u32,
 840    /// How many `char`s are in the last line
 841    pub last_line_chars: u32,
 842    /// How many UTF-16 code units are in the last line
 843    pub last_line_len_utf16: u32,
 844    /// The row idx of the longest row
 845    pub longest_row: u32,
 846    /// How many `char`s are in the longest row
 847    pub longest_row_chars: u32,
 848}
 849
 850impl From<TextSummary> for MBTextSummary {
 851    fn from(summary: TextSummary) -> Self {
 852        MBTextSummary {
 853            len: MultiBufferOffset(summary.len),
 854            chars: summary.chars,
 855            len_utf16: summary.len_utf16,
 856            lines: summary.lines,
 857            first_line_chars: summary.first_line_chars,
 858            last_line_chars: summary.last_line_chars,
 859            last_line_len_utf16: summary.last_line_len_utf16,
 860            longest_row: summary.longest_row,
 861            longest_row_chars: summary.longest_row_chars,
 862        }
 863    }
 864}
 865
 866impl From<MBTextSummary> for TextSummary {
 867    fn from(summary: MBTextSummary) -> Self {
 868        TextSummary {
 869            len: summary.len.0,
 870            chars: summary.chars,
 871            len_utf16: summary.len_utf16,
 872            lines: summary.lines,
 873            first_line_chars: summary.first_line_chars,
 874            last_line_chars: summary.last_line_chars,
 875            last_line_len_utf16: summary.last_line_len_utf16,
 876            longest_row: summary.longest_row,
 877            longest_row_chars: summary.longest_row_chars,
 878        }
 879    }
 880}
 881
 882impl From<&str> for MBTextSummary {
 883    fn from(text: &str) -> Self {
 884        MBTextSummary::from(TextSummary::from(text))
 885    }
 886}
 887
 888impl MultiBufferDimension for MBTextSummary {
 889    type TextDimension = TextSummary;
 890
 891    fn from_summary(summary: &MBTextSummary) -> Self {
 892        *summary
 893    }
 894
 895    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 896        *self += *summary;
 897    }
 898
 899    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 900        *self += *summary;
 901    }
 902}
 903
 904impl AddAssign for MBTextSummary {
 905    fn add_assign(&mut self, other: MBTextSummary) {
 906        let joined_chars = self.last_line_chars + other.first_line_chars;
 907        if joined_chars > self.longest_row_chars {
 908            self.longest_row = self.lines.row;
 909            self.longest_row_chars = joined_chars;
 910        }
 911        if other.longest_row_chars > self.longest_row_chars {
 912            self.longest_row = self.lines.row + other.longest_row;
 913            self.longest_row_chars = other.longest_row_chars;
 914        }
 915
 916        if self.lines.row == 0 {
 917            self.first_line_chars += other.first_line_chars;
 918        }
 919
 920        if other.lines.row == 0 {
 921            self.last_line_chars += other.first_line_chars;
 922            self.last_line_len_utf16 += other.last_line_len_utf16;
 923        } else {
 924            self.last_line_chars = other.last_line_chars;
 925            self.last_line_len_utf16 = other.last_line_len_utf16;
 926        }
 927
 928        self.chars += other.chars;
 929        self.len += other.len;
 930        self.len_utf16 += other.len_utf16;
 931        self.lines += other.lines;
 932    }
 933}
 934
 935impl AddAssign<TextSummary> for MBTextSummary {
 936    fn add_assign(&mut self, other: TextSummary) {
 937        *self += MBTextSummary::from(other);
 938    }
 939}
 940
 941impl MBTextSummary {
 942    pub fn lines_utf16(&self) -> PointUtf16 {
 943        PointUtf16 {
 944            row: self.lines.row,
 945            column: self.last_line_len_utf16,
 946        }
 947    }
 948}
 949
 950impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 951where
 952    K: MultiBufferDimension,
 953    V: MultiBufferDimension,
 954{
 955    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 956
 957    fn from_summary(summary: &MBTextSummary) -> Self {
 958        Self {
 959            key: K::from_summary(summary),
 960            value: Some(V::from_summary(summary)),
 961        }
 962    }
 963
 964    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 965        self.key.add_text_dim(&summary.key);
 966        if let Some(value) = &mut self.value {
 967            if let Some(other_value) = summary.value.as_ref() {
 968                value.add_text_dim(other_value);
 969            }
 970        }
 971    }
 972
 973    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 974        self.key.add_mb_text_summary(summary);
 975        if let Some(value) = &mut self.value {
 976            value.add_mb_text_summary(summary);
 977        }
 978    }
 979}
 980
 981#[derive(Clone)]
 982pub struct MultiBufferRows<'a> {
 983    point: Point,
 984    is_empty: bool,
 985    is_singleton: bool,
 986    cursor: MultiBufferCursor<'a, Point, Point>,
 987}
 988
 989pub struct MultiBufferChunks<'a> {
 990    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 991    diff_transforms:
 992        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 993    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 994    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 995    buffer_chunk: Option<Chunk<'a>>,
 996    range: Range<MultiBufferOffset>,
 997    excerpt_offset_range: Range<ExcerptOffset>,
 998    excerpt_chunks: Option<ExcerptChunks<'a>>,
 999    language_aware: bool,
1000}
1001
1002pub struct ReversedMultiBufferChunks<'a> {
1003    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1004    current_chunks: Option<rope::Chunks<'a>>,
1005    start: MultiBufferOffset,
1006    offset: MultiBufferOffset,
1007}
1008
1009pub struct MultiBufferBytes<'a> {
1010    range: Range<MultiBufferOffset>,
1011    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1012    excerpt_bytes: Option<text::Bytes<'a>>,
1013    has_trailing_newline: bool,
1014    chunk: &'a [u8],
1015}
1016
1017pub struct ReversedMultiBufferBytes<'a> {
1018    range: Range<MultiBufferOffset>,
1019    chunks: ReversedMultiBufferChunks<'a>,
1020    chunk: &'a [u8],
1021}
1022
1023#[derive(Clone)]
1024struct DiffTransforms<MBD> {
1025    output_dimension: OutputDimension<MBD>,
1026    excerpt_dimension: ExcerptDimension<MBD>,
1027}
1028
1029impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1030    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1031        Self {
1032            output_dimension: OutputDimension::zero(cx),
1033            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1034                cx,
1035            ),
1036        }
1037    }
1038
1039    fn add_summary(
1040        &mut self,
1041        summary: &'a DiffTransformSummary,
1042        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1043    ) {
1044        self.output_dimension.add_summary(summary, cx);
1045        self.excerpt_dimension.add_summary(summary, cx);
1046    }
1047}
1048
1049#[derive(Clone)]
1050struct MultiBufferCursor<'a, MBD, BD> {
1051    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1052    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1053    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1054    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1055}
1056
1057#[derive(Clone)]
1058struct MultiBufferRegion<'a, MBD, BD> {
1059    buffer: &'a BufferSnapshot,
1060    is_main_buffer: bool,
1061    diff_hunk_status: Option<DiffHunkStatus>,
1062    excerpt: &'a Excerpt,
1063    buffer_range: Range<BD>,
1064    range: Range<MBD>,
1065    has_trailing_newline: bool,
1066}
1067
1068struct ExcerptChunks<'a> {
1069    excerpt_id: ExcerptId,
1070    content_chunks: BufferChunks<'a>,
1071    has_footer: bool,
1072}
1073
1074#[derive(Debug)]
1075struct BufferEdit {
1076    range: Range<BufferOffset>,
1077    new_text: Arc<str>,
1078    is_insertion: bool,
1079    original_indent_column: Option<u32>,
1080    excerpt_id: ExcerptId,
1081}
1082
1083#[derive(Clone, Copy, Debug, PartialEq)]
1084enum DiffChangeKind {
1085    BufferEdited,
1086    DiffUpdated { base_changed: bool },
1087    ExpandOrCollapseHunks { expand: bool },
1088}
1089
1090#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1091pub enum ExpandExcerptDirection {
1092    Up,
1093    Down,
1094    UpAndDown,
1095}
1096
1097impl ExpandExcerptDirection {
1098    pub fn should_expand_up(&self) -> bool {
1099        match self {
1100            ExpandExcerptDirection::Up => true,
1101            ExpandExcerptDirection::Down => false,
1102            ExpandExcerptDirection::UpAndDown => true,
1103        }
1104    }
1105
1106    pub fn should_expand_down(&self) -> bool {
1107        match self {
1108            ExpandExcerptDirection::Up => false,
1109            ExpandExcerptDirection::Down => true,
1110            ExpandExcerptDirection::UpAndDown => true,
1111        }
1112    }
1113}
1114
1115#[derive(Clone, Debug, PartialEq)]
1116pub struct IndentGuide {
1117    pub buffer_id: BufferId,
1118    pub start_row: MultiBufferRow,
1119    pub end_row: MultiBufferRow,
1120    pub depth: u32,
1121    pub tab_size: u32,
1122    pub settings: IndentGuideSettings,
1123}
1124
1125impl IndentGuide {
1126    pub fn indent_level(&self) -> u32 {
1127        self.depth * self.tab_size
1128    }
1129}
1130
1131impl MultiBuffer {
1132    pub fn new(capability: Capability) -> Self {
1133        Self::new_(
1134            capability,
1135            MultiBufferSnapshot {
1136                show_headers: true,
1137                show_deleted_hunks: true,
1138                ..MultiBufferSnapshot::default()
1139            },
1140        )
1141    }
1142
1143    pub fn without_headers(capability: Capability) -> Self {
1144        Self::new_(
1145            capability,
1146            MultiBufferSnapshot {
1147                show_deleted_hunks: true,
1148                ..MultiBufferSnapshot::default()
1149            },
1150        )
1151    }
1152
1153    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1154        let mut this = Self::new_(
1155            buffer.read(cx).capability(),
1156            MultiBufferSnapshot {
1157                singleton: true,
1158                show_deleted_hunks: true,
1159                ..MultiBufferSnapshot::default()
1160            },
1161        );
1162        this.singleton = true;
1163        let buffer_id = buffer.read(cx).remote_id();
1164        this.push_excerpts(
1165            buffer,
1166            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1167                buffer_id,
1168            ))],
1169            cx,
1170        );
1171        this
1172    }
1173
1174    #[inline]
1175    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1176        Self {
1177            snapshot: RefCell::new(snapshot),
1178            buffers: Default::default(),
1179            diffs: HashMap::default(),
1180            subscriptions: Topic::default(),
1181            singleton: false,
1182            capability,
1183            title: None,
1184            excerpts_by_path: Default::default(),
1185            paths_by_excerpt: Default::default(),
1186            buffer_changed_since_sync: Default::default(),
1187            history: History::default(),
1188        }
1189    }
1190
1191    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1192        let mut buffers = BTreeMap::default();
1193        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1194        for (buffer_id, buffer_state) in self.buffers.iter() {
1195            buffer_state.buffer.update(new_cx, |buffer, _| {
1196                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1197            });
1198            buffers.insert(
1199                *buffer_id,
1200                BufferState {
1201                    buffer: buffer_state.buffer.clone(),
1202                    last_version: buffer_state.last_version.clone(),
1203                    last_non_text_state_update_count: buffer_state
1204                        .last_non_text_state_update_count
1205                        .clone(),
1206                    excerpts: buffer_state.excerpts.clone(),
1207                    _subscriptions: [
1208                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1209                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1210                    ],
1211                },
1212            );
1213        }
1214        let mut diff_bases = HashMap::default();
1215        for (buffer_id, diff) in self.diffs.iter() {
1216            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1217        }
1218        Self {
1219            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1220            buffers,
1221            excerpts_by_path: Default::default(),
1222            paths_by_excerpt: Default::default(),
1223            diffs: diff_bases,
1224            subscriptions: Default::default(),
1225            singleton: self.singleton,
1226            capability: self.capability,
1227            history: self.history.clone(),
1228            title: self.title.clone(),
1229            buffer_changed_since_sync,
1230        }
1231    }
1232
1233    pub fn set_group_interval(&mut self, group_interval: Duration) {
1234        self.history.set_group_interval(group_interval);
1235    }
1236
1237    pub fn with_title(mut self, title: String) -> Self {
1238        self.title = Some(title);
1239        self
1240    }
1241
1242    pub fn read_only(&self) -> bool {
1243        !self.capability.editable()
1244    }
1245
1246    pub fn capability(&self) -> Capability {
1247        self.capability
1248    }
1249
1250    /// Returns an up-to-date snapshot of the MultiBuffer.
1251    #[ztracing::instrument(skip_all)]
1252    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1253        self.sync(cx);
1254        self.snapshot.borrow().clone()
1255    }
1256
1257    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1258        self.sync(cx);
1259        self.snapshot.borrow()
1260    }
1261
1262    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1263        if self.singleton {
1264            Some(self.buffers.values().next().unwrap().buffer.clone())
1265        } else {
1266            None
1267        }
1268    }
1269
1270    pub fn is_singleton(&self) -> bool {
1271        self.singleton
1272    }
1273
1274    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1275        self.subscriptions.subscribe()
1276    }
1277
1278    pub fn is_dirty(&self, cx: &App) -> bool {
1279        self.read(cx).is_dirty()
1280    }
1281
1282    pub fn has_deleted_file(&self, cx: &App) -> bool {
1283        self.read(cx).has_deleted_file()
1284    }
1285
1286    pub fn has_conflict(&self, cx: &App) -> bool {
1287        self.read(cx).has_conflict()
1288    }
1289
1290    // The `is_empty` signature doesn't match what clippy expects
1291    #[allow(clippy::len_without_is_empty)]
1292    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1293        self.read(cx).len()
1294    }
1295
1296    pub fn is_empty(&self) -> bool {
1297        self.buffers.is_empty()
1298    }
1299
1300    pub fn edit<I, S, T>(
1301        &mut self,
1302        edits: I,
1303        autoindent_mode: Option<AutoindentMode>,
1304        cx: &mut Context<Self>,
1305    ) where
1306        I: IntoIterator<Item = (Range<S>, T)>,
1307        S: ToOffset,
1308        T: Into<Arc<str>>,
1309    {
1310        self.edit_internal(edits, autoindent_mode, true, cx);
1311    }
1312
1313    pub fn edit_non_coalesce<I, S, T>(
1314        &mut self,
1315        edits: I,
1316        autoindent_mode: Option<AutoindentMode>,
1317        cx: &mut Context<Self>,
1318    ) where
1319        I: IntoIterator<Item = (Range<S>, T)>,
1320        S: ToOffset,
1321        T: Into<Arc<str>>,
1322    {
1323        self.edit_internal(edits, autoindent_mode, false, cx);
1324    }
1325
1326    fn edit_internal<I, S, T>(
1327        &mut self,
1328        edits: I,
1329        autoindent_mode: Option<AutoindentMode>,
1330        coalesce_adjacent: bool,
1331        cx: &mut Context<Self>,
1332    ) where
1333        I: IntoIterator<Item = (Range<S>, T)>,
1334        S: ToOffset,
1335        T: Into<Arc<str>>,
1336    {
1337        if self.read_only() || self.buffers.is_empty() {
1338            return;
1339        }
1340        self.sync_mut(cx);
1341        let edits = edits
1342            .into_iter()
1343            .map(|(range, new_text)| {
1344                let mut range = range.start.to_offset(self.snapshot.get_mut())
1345                    ..range.end.to_offset(self.snapshot.get_mut());
1346                if range.start > range.end {
1347                    mem::swap(&mut range.start, &mut range.end);
1348                }
1349                (range, new_text.into())
1350            })
1351            .collect::<Vec<_>>();
1352
1353        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1354
1355        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1356        fn edit_internal(
1357            this: &mut MultiBuffer,
1358            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1359            mut autoindent_mode: Option<AutoindentMode>,
1360            coalesce_adjacent: bool,
1361            cx: &mut Context<MultiBuffer>,
1362        ) {
1363            let original_indent_columns = match &mut autoindent_mode {
1364                Some(AutoindentMode::Block {
1365                    original_indent_columns,
1366                }) => mem::take(original_indent_columns),
1367                _ => Default::default(),
1368            };
1369
1370            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1371                edits,
1372                this.snapshot.get_mut(),
1373                &original_indent_columns,
1374            );
1375
1376            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1377            for (buffer_id, mut edits) in buffer_edits {
1378                buffer_ids.push(buffer_id);
1379                edits.sort_by_key(|edit| edit.range.start);
1380                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1381                    let mut edits = edits.into_iter().peekable();
1382                    let mut insertions = Vec::new();
1383                    let mut original_indent_columns = Vec::new();
1384                    let mut deletions = Vec::new();
1385                    let empty_str: Arc<str> = Arc::default();
1386                    while let Some(BufferEdit {
1387                        mut range,
1388                        mut new_text,
1389                        mut is_insertion,
1390                        original_indent_column,
1391                        excerpt_id,
1392                    }) = edits.next()
1393                    {
1394                        while let Some(BufferEdit {
1395                            range: next_range,
1396                            is_insertion: next_is_insertion,
1397                            new_text: next_new_text,
1398                            excerpt_id: next_excerpt_id,
1399                            ..
1400                        }) = edits.peek()
1401                        {
1402                            let should_coalesce = if coalesce_adjacent {
1403                                range.end >= next_range.start
1404                            } else {
1405                                range.end > next_range.start
1406                            };
1407
1408                            if should_coalesce {
1409                                range.end = cmp::max(next_range.end, range.end);
1410                                is_insertion |= *next_is_insertion;
1411                                if excerpt_id == *next_excerpt_id {
1412                                    new_text = format!("{new_text}{next_new_text}").into();
1413                                }
1414                                edits.next();
1415                            } else {
1416                                break;
1417                            }
1418                        }
1419
1420                        if is_insertion {
1421                            original_indent_columns.push(original_indent_column);
1422                            insertions.push((
1423                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1424                                new_text.clone(),
1425                            ));
1426                        } else if !range.is_empty() {
1427                            deletions.push((
1428                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1429                                empty_str.clone(),
1430                            ));
1431                        }
1432                    }
1433
1434                    let deletion_autoindent_mode =
1435                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1436                            Some(AutoindentMode::Block {
1437                                original_indent_columns: Default::default(),
1438                            })
1439                        } else {
1440                            autoindent_mode.clone()
1441                        };
1442                    let insertion_autoindent_mode =
1443                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1444                            Some(AutoindentMode::Block {
1445                                original_indent_columns,
1446                            })
1447                        } else {
1448                            autoindent_mode.clone()
1449                        };
1450
1451                    if coalesce_adjacent {
1452                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1453                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1454                    } else {
1455                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1456                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1457                    }
1458                })
1459            }
1460
1461            cx.emit(Event::ExcerptsEdited {
1462                excerpt_ids: edited_excerpt_ids,
1463                buffer_ids,
1464            });
1465        }
1466    }
1467
1468    fn convert_edits_to_buffer_edits(
1469        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1470        snapshot: &MultiBufferSnapshot,
1471        original_indent_columns: &[Option<u32>],
1472    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1473        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1474        let mut edited_excerpt_ids = Vec::new();
1475        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1476        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1477            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1478
1479            cursor.seek(&range.start);
1480            let mut start_region = cursor.region().expect("start offset out of bounds");
1481            if !start_region.is_main_buffer {
1482                cursor.next();
1483                if let Some(region) = cursor.region() {
1484                    start_region = region;
1485                } else {
1486                    continue;
1487                }
1488            }
1489
1490            if range.end < start_region.range.start {
1491                continue;
1492            }
1493
1494            let start_region = start_region.clone();
1495            if range.end > start_region.range.end {
1496                cursor.seek_forward(&range.end);
1497            }
1498            let mut end_region = cursor.region().expect("end offset out of bounds");
1499            if !end_region.is_main_buffer {
1500                cursor.prev();
1501                if let Some(region) = cursor.region() {
1502                    end_region = region;
1503                } else {
1504                    continue;
1505                }
1506            }
1507
1508            if range.start > end_region.range.end {
1509                continue;
1510            }
1511
1512            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1513            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1514            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1515                .min(start_region.buffer_range.end);
1516            let buffer_end =
1517                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1518
1519            if start_region.excerpt.id == end_region.excerpt.id {
1520                if start_region.buffer.capability == Capability::ReadWrite
1521                    && start_region.is_main_buffer
1522                {
1523                    edited_excerpt_ids.push(start_region.excerpt.id);
1524                    buffer_edits
1525                        .entry(start_region.buffer.remote_id())
1526                        .or_default()
1527                        .push(BufferEdit {
1528                            range: buffer_start..buffer_end,
1529                            new_text,
1530                            is_insertion: true,
1531                            original_indent_column,
1532                            excerpt_id: start_region.excerpt.id,
1533                        });
1534                }
1535            } else {
1536                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1537                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1538                if start_region.buffer.capability == Capability::ReadWrite
1539                    && start_region.is_main_buffer
1540                {
1541                    edited_excerpt_ids.push(start_region.excerpt.id);
1542                    buffer_edits
1543                        .entry(start_region.buffer.remote_id())
1544                        .or_default()
1545                        .push(BufferEdit {
1546                            range: start_excerpt_range,
1547                            new_text: new_text.clone(),
1548                            is_insertion: true,
1549                            original_indent_column,
1550                            excerpt_id: start_region.excerpt.id,
1551                        });
1552                }
1553                let excerpt_id = end_region.excerpt.id;
1554                if end_region.buffer.capability == Capability::ReadWrite
1555                    && end_region.is_main_buffer
1556                {
1557                    edited_excerpt_ids.push(excerpt_id);
1558                    buffer_edits
1559                        .entry(end_region.buffer.remote_id())
1560                        .or_default()
1561                        .push(BufferEdit {
1562                            range: end_excerpt_range,
1563                            new_text: new_text.clone(),
1564                            is_insertion: false,
1565                            original_indent_column,
1566                            excerpt_id,
1567                        });
1568                }
1569
1570                cursor.seek(&range.start);
1571                cursor.next_excerpt();
1572                while let Some(region) = cursor.region() {
1573                    if region.excerpt.id == excerpt_id {
1574                        break;
1575                    }
1576                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1577                        edited_excerpt_ids.push(region.excerpt.id);
1578                        buffer_edits
1579                            .entry(region.buffer.remote_id())
1580                            .or_default()
1581                            .push(BufferEdit {
1582                                range: region.buffer_range.clone(),
1583                                new_text: new_text.clone(),
1584                                is_insertion: false,
1585                                original_indent_column,
1586                                excerpt_id: region.excerpt.id,
1587                            });
1588                    }
1589                    cursor.next_excerpt();
1590                }
1591            }
1592        }
1593        (buffer_edits, edited_excerpt_ids)
1594    }
1595
1596    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1597    where
1598        I: IntoIterator<Item = Range<S>>,
1599        S: ToOffset,
1600    {
1601        if self.read_only() || self.buffers.is_empty() {
1602            return;
1603        }
1604        self.sync_mut(cx);
1605        let empty = Arc::<str>::from("");
1606        let edits = ranges
1607            .into_iter()
1608            .map(|range| {
1609                let mut range = range.start.to_offset(self.snapshot.get_mut())
1610                    ..range.end.to_offset(&self.snapshot.get_mut());
1611                if range.start > range.end {
1612                    mem::swap(&mut range.start, &mut range.end);
1613                }
1614                (range, empty.clone())
1615            })
1616            .collect::<Vec<_>>();
1617
1618        return autoindent_ranges_internal(self, edits, cx);
1619
1620        fn autoindent_ranges_internal(
1621            this: &mut MultiBuffer,
1622            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1623            cx: &mut Context<MultiBuffer>,
1624        ) {
1625            let (buffer_edits, edited_excerpt_ids) =
1626                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1627
1628            let mut buffer_ids = Vec::new();
1629            for (buffer_id, mut edits) in buffer_edits {
1630                buffer_ids.push(buffer_id);
1631                edits.sort_unstable_by_key(|edit| edit.range.start);
1632
1633                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1634                for edit in edits {
1635                    if let Some(last_range) = ranges.last_mut()
1636                        && edit.range.start <= last_range.end
1637                    {
1638                        last_range.end = last_range.end.max(edit.range.end);
1639                        continue;
1640                    }
1641                    ranges.push(edit.range);
1642                }
1643
1644                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1645                    buffer.autoindent_ranges(ranges, cx);
1646                })
1647            }
1648
1649            cx.emit(Event::ExcerptsEdited {
1650                excerpt_ids: edited_excerpt_ids,
1651                buffer_ids,
1652            });
1653        }
1654    }
1655
1656    pub fn set_active_selections(
1657        &self,
1658        selections: &[Selection<Anchor>],
1659        line_mode: bool,
1660        cursor_shape: CursorShape,
1661        cx: &mut Context<Self>,
1662    ) {
1663        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1664            Default::default();
1665        let snapshot = self.read(cx);
1666        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1667        for selection in selections {
1668            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1669            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1670
1671            cursor.seek(&Some(start_locator), Bias::Left);
1672            while let Some(excerpt) = cursor.item()
1673                && excerpt.locator <= *end_locator
1674            {
1675                let mut start = excerpt.range.context.start;
1676                let mut end = excerpt.range.context.end;
1677                if excerpt.id == selection.start.excerpt_id {
1678                    start = selection.start.text_anchor;
1679                }
1680                if excerpt.id == selection.end.excerpt_id {
1681                    end = selection.end.text_anchor;
1682                }
1683                selections_by_buffer
1684                    .entry(excerpt.buffer_id)
1685                    .or_default()
1686                    .push(Selection {
1687                        id: selection.id,
1688                        start,
1689                        end,
1690                        reversed: selection.reversed,
1691                        goal: selection.goal,
1692                    });
1693
1694                cursor.next();
1695            }
1696        }
1697
1698        for (buffer_id, buffer_state) in self.buffers.iter() {
1699            if !selections_by_buffer.contains_key(buffer_id) {
1700                buffer_state
1701                    .buffer
1702                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1703            }
1704        }
1705
1706        for (buffer_id, mut selections) in selections_by_buffer {
1707            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1708                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1709                let mut selections = selections.into_iter().peekable();
1710                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1711                    let mut selection = selections.next()?;
1712                    while let Some(next_selection) = selections.peek() {
1713                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1714                            let next_selection = selections.next().unwrap();
1715                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1716                                selection.end = next_selection.end;
1717                            }
1718                        } else {
1719                            break;
1720                        }
1721                    }
1722                    Some(selection)
1723                }));
1724                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1725            });
1726        }
1727    }
1728
1729    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1730        for buffer in self.buffers.values() {
1731            buffer
1732                .buffer
1733                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1734        }
1735    }
1736
1737    pub fn push_excerpts<O>(
1738        &mut self,
1739        buffer: Entity<Buffer>,
1740        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1741        cx: &mut Context<Self>,
1742    ) -> Vec<ExcerptId>
1743    where
1744        O: text::ToOffset,
1745    {
1746        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1747    }
1748
1749    #[instrument(skip_all)]
1750    fn merge_excerpt_ranges<'a>(
1751        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1752    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1753        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1754        let mut counts: Vec<usize> = Vec::new();
1755        for range in expanded_ranges {
1756            if let Some(last_range) = merged_ranges.last_mut() {
1757                assert!(
1758                    last_range.context.start <= range.context.start,
1759                    "ranges must be sorted: {last_range:?} <= {range:?}"
1760                );
1761                if last_range.context.end >= range.context.start
1762                    || last_range.context.end.row + 1 == range.context.start.row
1763                {
1764                    last_range.context.end = range.context.end.max(last_range.context.end);
1765                    *counts.last_mut().unwrap() += 1;
1766                    continue;
1767                }
1768            }
1769            merged_ranges.push(range.clone());
1770            counts.push(1);
1771        }
1772        (merged_ranges, counts)
1773    }
1774
1775    pub fn insert_excerpts_after<O>(
1776        &mut self,
1777        prev_excerpt_id: ExcerptId,
1778        buffer: Entity<Buffer>,
1779        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1780        cx: &mut Context<Self>,
1781    ) -> Vec<ExcerptId>
1782    where
1783        O: text::ToOffset,
1784    {
1785        let mut ids = Vec::new();
1786        let mut next_excerpt_id =
1787            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1788                last_entry.id.0 + 1
1789            } else {
1790                1
1791            };
1792        self.insert_excerpts_with_ids_after(
1793            prev_excerpt_id,
1794            buffer,
1795            ranges.into_iter().map(|range| {
1796                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1797                ids.push(id);
1798                (id, range)
1799            }),
1800            cx,
1801        );
1802        ids
1803    }
1804
1805    pub fn insert_excerpts_with_ids_after<O>(
1806        &mut self,
1807        prev_excerpt_id: ExcerptId,
1808        buffer: Entity<Buffer>,
1809        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1810        cx: &mut Context<Self>,
1811    ) where
1812        O: text::ToOffset,
1813    {
1814        assert_eq!(self.history.transaction_depth(), 0);
1815        let mut ranges = ranges.into_iter().peekable();
1816        if ranges.peek().is_none() {
1817            return Default::default();
1818        }
1819
1820        self.sync_mut(cx);
1821
1822        let buffer_snapshot = buffer.read(cx).snapshot();
1823        let buffer_id = buffer_snapshot.remote_id();
1824
1825        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1826            self.buffer_changed_since_sync.replace(true);
1827            buffer.update(cx, |buffer, _| {
1828                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1829            });
1830            BufferState {
1831                last_version: RefCell::new(buffer_snapshot.version().clone()),
1832                last_non_text_state_update_count: Cell::new(
1833                    buffer_snapshot.non_text_state_update_count(),
1834                ),
1835                excerpts: Default::default(),
1836                _subscriptions: [
1837                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1838                    cx.subscribe(&buffer, Self::on_buffer_event),
1839                ],
1840                buffer: buffer.clone(),
1841            }
1842        });
1843
1844        let mut snapshot = self.snapshot.get_mut();
1845
1846        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1847        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1848        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1849        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1850        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1851
1852        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1853        new_excerpts.update_last(
1854            |excerpt| {
1855                excerpt.has_trailing_newline = true;
1856            },
1857            (),
1858        );
1859
1860        let next_locator = if let Some(excerpt) = cursor.item() {
1861            excerpt.locator.clone()
1862        } else {
1863            Locator::max()
1864        };
1865
1866        let mut excerpts = Vec::new();
1867        let buffer_snapshot = Arc::new(buffer_snapshot);
1868        while let Some((id, range)) = ranges.next() {
1869            let locator = Locator::between(&prev_locator, &next_locator);
1870            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1871                buffer_state.excerpts.insert(ix, locator.clone());
1872            }
1873            let range = ExcerptRange {
1874                context: buffer_snapshot.anchor_before(&range.context.start)
1875                    ..buffer_snapshot.anchor_after(&range.context.end),
1876                primary: buffer_snapshot.anchor_before(&range.primary.start)
1877                    ..buffer_snapshot.anchor_after(&range.primary.end),
1878            };
1879            excerpts.push((id, range.clone()));
1880            let excerpt = Excerpt::new(
1881                id,
1882                locator.clone(),
1883                buffer_id,
1884                buffer_snapshot.clone(),
1885                range,
1886                ranges.peek().is_some() || cursor.item().is_some(),
1887            );
1888            new_excerpts.push(excerpt, ());
1889            prev_locator = locator.clone();
1890
1891            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1892                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1893            }
1894            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1895        }
1896        snapshot
1897            .buffer_locators
1898            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1899
1900        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1901
1902        let suffix = cursor.suffix();
1903        let changed_trailing_excerpt = suffix.is_empty();
1904        new_excerpts.append(suffix, ());
1905        drop(cursor);
1906        snapshot.excerpts = new_excerpts;
1907        snapshot.excerpt_ids = new_excerpt_ids;
1908        if changed_trailing_excerpt {
1909            snapshot.trailing_excerpt_update_count += 1;
1910        }
1911
1912        let edits = Self::sync_diff_transforms(
1913            &mut snapshot,
1914            vec![Edit {
1915                old: edit_start..edit_start,
1916                new: edit_start..edit_end,
1917            }],
1918            DiffChangeKind::BufferEdited,
1919        );
1920        if !edits.is_empty() {
1921            self.subscriptions.publish(edits);
1922        }
1923
1924        cx.emit(Event::Edited {
1925            edited_buffer: None,
1926        });
1927        cx.emit(Event::ExcerptsAdded {
1928            buffer,
1929            predecessor: prev_excerpt_id,
1930            excerpts,
1931        });
1932        cx.notify();
1933    }
1934
1935    pub fn clear(&mut self, cx: &mut Context<Self>) {
1936        self.sync_mut(cx);
1937        let ids = self.excerpt_ids();
1938        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1939        self.excerpts_by_path.clear();
1940        self.paths_by_excerpt.clear();
1941        let MultiBufferSnapshot {
1942            excerpts,
1943            buffer_locators,
1944            diffs: _,
1945            diff_transforms: _,
1946            non_text_state_update_count: _,
1947            edit_count: _,
1948            is_dirty,
1949            has_deleted_file,
1950            has_conflict,
1951            has_inverted_diff,
1952            singleton: _,
1953            excerpt_ids: _,
1954            replaced_excerpts,
1955            trailing_excerpt_update_count,
1956            all_diff_hunks_expanded: _,
1957            show_deleted_hunks: _,
1958            use_extended_diff_range: _,
1959            show_headers: _,
1960        } = self.snapshot.get_mut();
1961        buffer_locators.clear();
1962        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1963        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1964        *excerpts = Default::default();
1965        *trailing_excerpt_update_count += 1;
1966        *is_dirty = false;
1967        *has_deleted_file = false;
1968        *has_conflict = false;
1969        *has_inverted_diff = false;
1970        replaced_excerpts.clear();
1971
1972        let edits = Self::sync_diff_transforms(
1973            self.snapshot.get_mut(),
1974            vec![Edit {
1975                old: start..prev_len,
1976                new: start..start,
1977            }],
1978            DiffChangeKind::BufferEdited,
1979        );
1980        if !edits.is_empty() {
1981            self.subscriptions.publish(edits);
1982        }
1983        cx.emit(Event::Edited {
1984            edited_buffer: None,
1985        });
1986        cx.emit(Event::ExcerptsRemoved {
1987            ids,
1988            removed_buffer_ids,
1989        });
1990        cx.notify();
1991    }
1992
1993    #[ztracing::instrument(skip_all)]
1994    pub fn excerpts_for_buffer(
1995        &self,
1996        buffer_id: BufferId,
1997        cx: &App,
1998    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1999        let mut excerpts = Vec::new();
2000        let snapshot = self.read(cx);
2001        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
2002        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
2003            for locator in &**locators {
2004                cursor.seek_forward(&Some(locator), Bias::Left);
2005                if let Some(excerpt) = cursor.item()
2006                    && excerpt.locator == *locator
2007                {
2008                    excerpts.push((excerpt.id, excerpt.range.clone()));
2009                }
2010            }
2011        }
2012
2013        excerpts
2014    }
2015
2016    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2017        let snapshot = self.read(cx);
2018        let mut excerpts = snapshot
2019            .excerpts
2020            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2021        let mut diff_transforms = snapshot
2022            .diff_transforms
2023            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2024        diff_transforms.next();
2025        let locators = snapshot
2026            .buffer_locators
2027            .get(&buffer_id)
2028            .into_iter()
2029            .flat_map(|v| &**v);
2030        let mut result = Vec::new();
2031        for locator in locators {
2032            excerpts.seek_forward(&Some(locator), Bias::Left);
2033            if let Some(excerpt) = excerpts.item()
2034                && excerpt.locator == *locator
2035            {
2036                let excerpt_start = excerpts.start().1;
2037                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2038
2039                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2040                let overshoot = excerpt_start - diff_transforms.start().0;
2041                let start = diff_transforms.start().1 + overshoot;
2042
2043                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2044                let overshoot = excerpt_end - diff_transforms.start().0;
2045                let end = diff_transforms.start().1 + overshoot;
2046
2047                result.push(start.0..end.0)
2048            }
2049        }
2050        result
2051    }
2052
2053    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2054        self.snapshot
2055            .borrow()
2056            .excerpts
2057            .iter()
2058            .map(|entry| entry.buffer_id)
2059            .collect()
2060    }
2061
2062    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2063        let snapshot = self.snapshot.borrow();
2064        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2065        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2066        ids
2067    }
2068
2069    pub fn excerpt_containing(
2070        &self,
2071        position: impl ToOffset,
2072        cx: &App,
2073    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2074        let snapshot = self.read(cx);
2075        let offset = position.to_offset(&snapshot);
2076
2077        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2078        cursor.seek(&offset);
2079        cursor
2080            .excerpt()
2081            .or_else(|| snapshot.excerpts.last())
2082            .map(|excerpt| {
2083                (
2084                    excerpt.id,
2085                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2086                    excerpt.range.context.clone(),
2087                )
2088            })
2089    }
2090
2091    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2092        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2093            self.buffer(buffer_id)
2094        } else {
2095            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2096            Some(buffer)
2097        }
2098    }
2099
2100    // If point is at the end of the buffer, the last excerpt is returned
2101    pub fn point_to_buffer_offset<T: ToOffset>(
2102        &self,
2103        point: T,
2104        cx: &App,
2105    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2106        let snapshot = self.read(cx);
2107        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2108        Some((
2109            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2110            offset,
2111        ))
2112    }
2113
2114    // If point is at the end of the buffer, the last excerpt is returned
2115    pub fn point_to_buffer_point<T: ToPoint>(
2116        &self,
2117        point: T,
2118        cx: &App,
2119    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2120        let snapshot = self.read(cx);
2121        let (buffer, point, is_main_buffer) =
2122            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2123        Some((
2124            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2125            point,
2126            is_main_buffer,
2127        ))
2128    }
2129
2130    pub fn buffer_point_to_anchor(
2131        &self,
2132        // todo(lw): We shouldn't need this?
2133        buffer: &Entity<Buffer>,
2134        point: Point,
2135        cx: &App,
2136    ) -> Option<Anchor> {
2137        let mut found = None;
2138        let snapshot = buffer.read(cx).snapshot();
2139        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2140            let start = range.context.start.to_point(&snapshot);
2141            let end = range.context.end.to_point(&snapshot);
2142            if start <= point && point < end {
2143                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2144                break;
2145            }
2146            if point < start {
2147                found = Some((start, excerpt_id));
2148            }
2149            if point > end {
2150                found = Some((end, excerpt_id));
2151            }
2152        }
2153
2154        found.map(|(point, excerpt_id)| {
2155            let text_anchor = snapshot.anchor_after(point);
2156            Anchor::in_buffer(excerpt_id, text_anchor)
2157        })
2158    }
2159
2160    pub fn buffer_anchor_to_anchor(
2161        &self,
2162        // todo(lw): We shouldn't need this?
2163        buffer: &Entity<Buffer>,
2164        anchor: text::Anchor,
2165        cx: &App,
2166    ) -> Option<Anchor> {
2167        let snapshot = buffer.read(cx).snapshot();
2168        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2169            if range.context.start.cmp(&anchor, &snapshot).is_le()
2170                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2171            {
2172                return Some(Anchor::in_buffer(excerpt_id, anchor));
2173            }
2174        }
2175
2176        None
2177    }
2178
2179    pub fn merge_excerpts(
2180        &mut self,
2181        excerpt_ids: &[ExcerptId],
2182        cx: &mut Context<Self>,
2183    ) -> ExcerptId {
2184        debug_assert!(!excerpt_ids.is_empty());
2185        if excerpt_ids.len() == 1 {
2186            return excerpt_ids[0];
2187        }
2188
2189        let snapshot = self.snapshot(cx);
2190
2191        let first_range = snapshot
2192            .context_range_for_excerpt(excerpt_ids[0])
2193            .expect("first excerpt must exist");
2194        let last_range = snapshot
2195            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2196            .expect("last excerpt must exist");
2197
2198        let union_range = first_range.start..last_range.end;
2199
2200        drop(snapshot);
2201
2202        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2203        let removed = &excerpt_ids[1..];
2204        for &excerpt_id in removed {
2205            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2206                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2207                    excerpt_list.retain(|id| *id != excerpt_id);
2208                    if excerpt_list.is_empty() {
2209                        let path = path.clone();
2210                        self.excerpts_by_path.remove(&path);
2211                    }
2212                }
2213            }
2214        }
2215        self.remove_excerpts(removed.iter().copied(), cx);
2216
2217        excerpt_ids[0]
2218    }
2219
2220    pub fn remove_excerpts(
2221        &mut self,
2222        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2223        cx: &mut Context<Self>,
2224    ) {
2225        self.sync_mut(cx);
2226        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2227        if ids.is_empty() {
2228            return;
2229        }
2230        self.buffer_changed_since_sync.replace(true);
2231
2232        let mut snapshot = self.snapshot.get_mut();
2233        let mut new_excerpts = SumTree::default();
2234        let mut cursor = snapshot
2235            .excerpts
2236            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2237        let mut edits = Vec::new();
2238        let mut excerpt_ids = ids.iter().copied().peekable();
2239        let mut removed_buffer_ids = Vec::new();
2240        let mut removed_excerpts_for_buffers = HashSet::default();
2241
2242        while let Some(excerpt_id) = excerpt_ids.next() {
2243            self.paths_by_excerpt.remove(&excerpt_id);
2244            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2245            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2246            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2247
2248            if let Some(mut excerpt) = cursor.item() {
2249                if excerpt.id != excerpt_id {
2250                    continue;
2251                }
2252                let mut old_start = cursor.start().1;
2253
2254                // Skip over the removed excerpt.
2255                'remove_excerpts: loop {
2256                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2257                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2258                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2259                        if buffer_state.excerpts.is_empty() {
2260                            log::debug!(
2261                                "removing buffer and diff for buffer {}",
2262                                excerpt.buffer_id
2263                            );
2264                            self.buffers.remove(&excerpt.buffer_id);
2265                            removed_buffer_ids.push(excerpt.buffer_id);
2266                        }
2267                    }
2268                    cursor.next();
2269
2270                    // Skip over any subsequent excerpts that are also removed.
2271                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2272                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2273                        if let Some(next_excerpt) = cursor.item()
2274                            && next_excerpt.locator == *next_locator
2275                        {
2276                            excerpt_ids.next();
2277                            excerpt = next_excerpt;
2278                            continue 'remove_excerpts;
2279                        }
2280                    }
2281
2282                    break;
2283                }
2284
2285                // When removing the last excerpt, remove the trailing newline from
2286                // the previous excerpt.
2287                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2288                    old_start -= 1;
2289                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2290                }
2291
2292                // Push an edit for the removal of this run of excerpts.
2293                let old_end = cursor.start().1;
2294                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2295                edits.push(Edit {
2296                    old: old_start..old_end,
2297                    new: new_start..new_start,
2298                });
2299            }
2300        }
2301        let suffix = cursor.suffix();
2302        let changed_trailing_excerpt = suffix.is_empty();
2303        new_excerpts.append(suffix, ());
2304        drop(cursor);
2305        for buffer_id in removed_excerpts_for_buffers {
2306            match self.buffers.get(&buffer_id) {
2307                Some(buffer_state) => {
2308                    snapshot
2309                        .buffer_locators
2310                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2311                }
2312                None => {
2313                    snapshot.buffer_locators.remove(&buffer_id);
2314                }
2315            }
2316        }
2317        snapshot.excerpts = new_excerpts;
2318        for buffer_id in &removed_buffer_ids {
2319            self.diffs.remove(buffer_id);
2320            snapshot.diffs.remove(buffer_id);
2321        }
2322
2323        // Recalculate has_inverted_diff after removing diffs
2324        if !removed_buffer_ids.is_empty() {
2325            snapshot.has_inverted_diff = snapshot
2326                .diffs
2327                .iter()
2328                .any(|(_, diff)| diff.main_buffer.is_some());
2329        }
2330
2331        if changed_trailing_excerpt {
2332            snapshot.trailing_excerpt_update_count += 1;
2333        }
2334
2335        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2336        if !edits.is_empty() {
2337            self.subscriptions.publish(edits);
2338        }
2339        cx.emit(Event::Edited {
2340            edited_buffer: None,
2341        });
2342        cx.emit(Event::ExcerptsRemoved {
2343            ids,
2344            removed_buffer_ids,
2345        });
2346        cx.notify();
2347    }
2348
2349    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2350        &self,
2351        anchors: Anchors,
2352        cx: &mut Context<Self>,
2353    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2354        let mut error = None;
2355        let mut futures = Vec::new();
2356        for anchor in anchors {
2357            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2358                if let Some(buffer) = self.buffers.get(&buffer_id) {
2359                    buffer.buffer.update(cx, |buffer, _| {
2360                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2361                    });
2362                } else {
2363                    error = Some(anyhow!(
2364                        "buffer {buffer_id} is not part of this multi-buffer"
2365                    ));
2366                    break;
2367                }
2368            }
2369        }
2370        async move {
2371            if let Some(error) = error {
2372                Err(error)?;
2373            }
2374            for future in futures {
2375                future.await?;
2376            }
2377            Ok(())
2378        }
2379    }
2380
2381    pub fn text_anchor_for_position<T: ToOffset>(
2382        &self,
2383        position: T,
2384        cx: &App,
2385    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2386        let snapshot = self.read(cx);
2387        let anchor = snapshot.anchor_before(position);
2388        let buffer = self
2389            .buffers
2390            .get(&anchor.text_anchor.buffer_id?)?
2391            .buffer
2392            .clone();
2393        Some((buffer, anchor.text_anchor))
2394    }
2395
2396    fn on_buffer_event(
2397        &mut self,
2398        buffer: Entity<Buffer>,
2399        event: &language::BufferEvent,
2400        cx: &mut Context<Self>,
2401    ) {
2402        use language::BufferEvent;
2403        let buffer_id = buffer.read(cx).remote_id();
2404        cx.emit(match event {
2405            BufferEvent::Edited => Event::Edited {
2406                edited_buffer: Some(buffer),
2407            },
2408            BufferEvent::DirtyChanged => Event::DirtyChanged,
2409            BufferEvent::Saved => Event::Saved,
2410            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2411            BufferEvent::Reloaded => Event::Reloaded,
2412            BufferEvent::LanguageChanged(has_language) => {
2413                Event::LanguageChanged(buffer_id, *has_language)
2414            }
2415            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2416            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2417            BufferEvent::CapabilityChanged => {
2418                self.capability = buffer.read(cx).capability();
2419                return;
2420            }
2421            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2422        });
2423    }
2424
2425    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2426        let diff = diff.read(cx);
2427        let buffer_id = diff.buffer_id;
2428        let diff = DiffStateSnapshot {
2429            diff: diff.snapshot(cx),
2430            main_buffer: None,
2431        };
2432        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2433    }
2434
2435    fn inverted_buffer_diff_language_changed(
2436        &mut self,
2437        diff: Entity<BufferDiff>,
2438        main_buffer: Entity<language::Buffer>,
2439        cx: &mut Context<Self>,
2440    ) {
2441        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2442        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2443        let diff = diff.read(cx);
2444        let diff = DiffStateSnapshot {
2445            diff: diff.snapshot(cx),
2446            main_buffer: Some(main_buffer_snapshot),
2447        };
2448        self.snapshot
2449            .get_mut()
2450            .diffs
2451            .insert(base_text_buffer_id, diff);
2452    }
2453
2454    fn buffer_diff_changed(
2455        &mut self,
2456        diff: Entity<BufferDiff>,
2457        range: Range<text::Anchor>,
2458        cx: &mut Context<Self>,
2459    ) {
2460        self.sync_mut(cx);
2461
2462        let diff = diff.read(cx);
2463        let buffer_id = diff.buffer_id;
2464
2465        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2466            return;
2467        };
2468        let new_diff = DiffStateSnapshot {
2469            diff: diff.snapshot(cx),
2470            main_buffer: None,
2471        };
2472        let mut snapshot = self.snapshot.get_mut();
2473        let base_text_changed = snapshot
2474            .diffs
2475            .get(&buffer_id)
2476            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2477        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2478
2479        let buffer = buffer_state.buffer.read(cx);
2480        let diff_change_range = range.to_offset(buffer);
2481
2482        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2483        let edits = Self::sync_diff_transforms(
2484            &mut snapshot,
2485            excerpt_edits,
2486            DiffChangeKind::DiffUpdated {
2487                base_changed: base_text_changed,
2488            },
2489        );
2490        if !edits.is_empty() {
2491            self.subscriptions.publish(edits);
2492        }
2493        cx.emit(Event::Edited {
2494            edited_buffer: None,
2495        });
2496    }
2497
2498    fn inverted_buffer_diff_changed(
2499        &mut self,
2500        diff: Entity<BufferDiff>,
2501        main_buffer: Entity<language::Buffer>,
2502        diff_change_range: Option<Range<usize>>,
2503        cx: &mut Context<Self>,
2504    ) {
2505        self.sync_mut(cx);
2506
2507        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2508        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2509            return;
2510        };
2511
2512        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2513        let diff = diff.read(cx);
2514        let new_diff = DiffStateSnapshot {
2515            diff: diff.snapshot(cx),
2516            main_buffer: Some(main_buffer_snapshot),
2517        };
2518        let mut snapshot = self.snapshot.get_mut();
2519        snapshot
2520            .diffs
2521            .insert_or_replace(base_text_buffer_id, new_diff);
2522
2523        let Some(diff_change_range) = diff_change_range else {
2524            return;
2525        };
2526
2527        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2528        let edits = Self::sync_diff_transforms(
2529            &mut snapshot,
2530            excerpt_edits,
2531            DiffChangeKind::DiffUpdated {
2532                // We don't read this field for inverted diffs.
2533                base_changed: false,
2534            },
2535        );
2536        if !edits.is_empty() {
2537            self.subscriptions.publish(edits);
2538        }
2539        cx.emit(Event::Edited {
2540            edited_buffer: None,
2541        });
2542    }
2543
2544    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2545        self.buffers.values().map(|state| state.buffer.clone())
2546    }
2547
2548    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2549        self.all_buffers_iter().collect()
2550    }
2551
2552    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2553        self.buffers.keys().copied()
2554    }
2555
2556    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2557        self.all_buffer_ids_iter().collect()
2558    }
2559
2560    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2561        self.buffers
2562            .get(&buffer_id)
2563            .map(|state| state.buffer.clone())
2564    }
2565
2566    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2567        self.point_to_buffer_offset(point, cx)
2568            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2569    }
2570
2571    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2572        let buffer_id = self
2573            .snapshot
2574            .borrow()
2575            .excerpts
2576            .first()
2577            .map(|excerpt| excerpt.buffer.remote_id());
2578        buffer_id
2579            .and_then(|buffer_id| self.buffer(buffer_id))
2580            .map(|buffer| {
2581                let buffer = buffer.read(cx);
2582                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2583            })
2584            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2585    }
2586
2587    pub fn language_settings_at<'a, T: ToOffset>(
2588        &'a self,
2589        point: T,
2590        cx: &'a App,
2591    ) -> Cow<'a, LanguageSettings> {
2592        let mut language = None;
2593        let mut file = None;
2594        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2595            let buffer = buffer.read(cx);
2596            language = buffer.language_at(offset);
2597            file = buffer.file();
2598        }
2599        language_settings(language.map(|l| l.name()), file, cx)
2600    }
2601
2602    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2603        self.buffers.values().for_each(|state| f(&state.buffer))
2604    }
2605
2606    pub fn explicit_title(&self) -> Option<&str> {
2607        self.title.as_deref()
2608    }
2609
2610    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2611        if let Some(title) = self.title.as_ref() {
2612            return title.into();
2613        }
2614
2615        if let Some(buffer) = self.as_singleton() {
2616            let buffer = buffer.read(cx);
2617
2618            if let Some(file) = buffer.file() {
2619                return file.file_name(cx).into();
2620            }
2621
2622            if let Some(title) = self.buffer_content_title(buffer) {
2623                return title;
2624            }
2625        };
2626
2627        "untitled".into()
2628    }
2629
2630    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2631        let mut is_leading_whitespace = true;
2632        let mut count = 0;
2633        let mut prev_was_space = false;
2634        let mut title = String::new();
2635
2636        for ch in buffer.snapshot().chars() {
2637            if is_leading_whitespace && ch.is_whitespace() {
2638                continue;
2639            }
2640
2641            is_leading_whitespace = false;
2642
2643            if ch == '\n' || count >= 40 {
2644                break;
2645            }
2646
2647            if ch.is_whitespace() {
2648                if !prev_was_space {
2649                    title.push(' ');
2650                    count += 1;
2651                    prev_was_space = true;
2652                }
2653            } else {
2654                title.push(ch);
2655                count += 1;
2656                prev_was_space = false;
2657            }
2658        }
2659
2660        let title = title.trim_end().to_string();
2661
2662        if title.is_empty() {
2663            return None;
2664        }
2665
2666        Some(title.into())
2667    }
2668
2669    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2670        self.title = Some(title);
2671        cx.notify();
2672    }
2673
2674    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2675    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2676        for buffer_state in self.buffers.values() {
2677            buffer_state
2678                .buffer
2679                .update(cx, |buffer, _cx| buffer.refresh_preview());
2680        }
2681    }
2682
2683    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2684    pub fn preserve_preview(&self, cx: &App) -> bool {
2685        self.buffers
2686            .values()
2687            .all(|state| state.buffer.read(cx).preserve_preview())
2688    }
2689
2690    #[cfg(any(test, feature = "test-support"))]
2691    pub fn is_parsing(&self, cx: &App) -> bool {
2692        self.as_singleton().unwrap().read(cx).is_parsing()
2693    }
2694
2695    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2696        let buffer_id = diff.read(cx).buffer_id;
2697
2698        if let Some(existing_diff) = self.diff_for(buffer_id)
2699            && diff.entity_id() == existing_diff.entity_id()
2700        {
2701            return;
2702        }
2703
2704        self.buffer_diff_changed(
2705            diff.clone(),
2706            text::Anchor::min_max_range_for_buffer(buffer_id),
2707            cx,
2708        );
2709        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2710    }
2711
2712    pub fn add_inverted_diff(
2713        &mut self,
2714        diff: Entity<BufferDiff>,
2715        main_buffer: Entity<language::Buffer>,
2716        cx: &mut Context<Self>,
2717    ) {
2718        let snapshot = diff.read(cx).base_text(cx);
2719        let base_text_buffer_id = snapshot.remote_id();
2720        let diff_change_range = 0..snapshot.len();
2721        self.snapshot.get_mut().has_inverted_diff = true;
2722        self.inverted_buffer_diff_changed(
2723            diff.clone(),
2724            main_buffer.clone(),
2725            Some(diff_change_range),
2726            cx,
2727        );
2728        self.diffs.insert(
2729            base_text_buffer_id,
2730            DiffState::new_inverted(diff, main_buffer, cx),
2731        );
2732    }
2733
2734    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2735        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2736    }
2737
2738    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2739        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2740    }
2741
2742    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2743        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2744    }
2745
2746    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2747        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2748        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2749    }
2750
2751    pub fn all_diff_hunks_expanded(&self) -> bool {
2752        self.snapshot.borrow().all_diff_hunks_expanded
2753    }
2754
2755    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2756        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2757        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2758    }
2759
2760    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2761        self.snapshot.get_mut().show_deleted_hunks = show;
2762
2763        self.sync_mut(cx);
2764
2765        let old_len = self.snapshot.borrow().len();
2766
2767        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2768        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2769
2770        let new_len = self.snapshot.borrow().len();
2771
2772        self.subscriptions.publish(vec![Edit {
2773            old: MultiBufferOffset(0)..old_len,
2774            new: MultiBufferOffset(0)..new_len,
2775        }]);
2776
2777        cx.emit(Event::DiffHunksToggled);
2778        cx.emit(Event::Edited {
2779            edited_buffer: None,
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        });
2897    }
2898
2899    pub fn resize_excerpt(
2900        &mut self,
2901        id: ExcerptId,
2902        range: Range<text::Anchor>,
2903        cx: &mut Context<Self>,
2904    ) {
2905        self.sync_mut(cx);
2906
2907        let mut snapshot = self.snapshot.get_mut();
2908        let locator = snapshot.excerpt_locator_for_id(id);
2909        let mut new_excerpts = SumTree::default();
2910        let mut cursor = snapshot
2911            .excerpts
2912            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2913        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2914
2915        let prefix = cursor.slice(&Some(locator), Bias::Left);
2916        new_excerpts.append(prefix, ());
2917
2918        let mut excerpt = cursor.item().unwrap().clone();
2919        let old_text_len = excerpt.text_summary.len;
2920
2921        excerpt.range.context.start = range.start;
2922        excerpt.range.context.end = range.end;
2923        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2924
2925        excerpt.text_summary = excerpt
2926            .buffer
2927            .text_summary_for_range(excerpt.range.context.clone());
2928
2929        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2930        let old_start_offset = cursor.start().1;
2931        let new_text_len = excerpt.text_summary.len;
2932        let edit = Edit {
2933            old: old_start_offset..old_start_offset + old_text_len,
2934            new: new_start_offset..new_start_offset + new_text_len,
2935        };
2936
2937        if let Some(last_edit) = edits.last_mut() {
2938            if last_edit.old.end == edit.old.start {
2939                last_edit.old.end = edit.old.end;
2940                last_edit.new.end = edit.new.end;
2941            } else {
2942                edits.push(edit);
2943            }
2944        } else {
2945            edits.push(edit);
2946        }
2947
2948        new_excerpts.push(excerpt, ());
2949
2950        cursor.next();
2951
2952        new_excerpts.append(cursor.suffix(), ());
2953
2954        drop(cursor);
2955        snapshot.excerpts = new_excerpts;
2956
2957        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2958        if !edits.is_empty() {
2959            self.subscriptions.publish(edits);
2960        }
2961        cx.emit(Event::Edited {
2962            edited_buffer: None,
2963        });
2964        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2965        cx.notify();
2966    }
2967
2968    pub fn expand_excerpts(
2969        &mut self,
2970        ids: impl IntoIterator<Item = ExcerptId>,
2971        line_count: u32,
2972        direction: ExpandExcerptDirection,
2973        cx: &mut Context<Self>,
2974    ) {
2975        if line_count == 0 {
2976            return;
2977        }
2978        self.sync_mut(cx);
2979        if !self.excerpts_by_path.is_empty() {
2980            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2981            return;
2982        }
2983        let mut snapshot = self.snapshot.get_mut();
2984
2985        let ids = ids.into_iter().collect::<Vec<_>>();
2986        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2987        let mut new_excerpts = SumTree::default();
2988        let mut cursor = snapshot
2989            .excerpts
2990            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2991        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2992
2993        for locator in &locators {
2994            let prefix = cursor.slice(&Some(locator), Bias::Left);
2995            new_excerpts.append(prefix, ());
2996
2997            let mut excerpt = cursor.item().unwrap().clone();
2998            let old_text_len = excerpt.text_summary.len;
2999
3000            let up_line_count = if direction.should_expand_up() {
3001                line_count
3002            } else {
3003                0
3004            };
3005
3006            let start_row = excerpt
3007                .range
3008                .context
3009                .start
3010                .to_point(&excerpt.buffer)
3011                .row
3012                .saturating_sub(up_line_count);
3013            let start_point = Point::new(start_row, 0);
3014            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3015
3016            let down_line_count = if direction.should_expand_down() {
3017                line_count
3018            } else {
3019                0
3020            };
3021
3022            let mut end_point = excerpt.buffer.clip_point(
3023                excerpt.range.context.end.to_point(&excerpt.buffer)
3024                    + Point::new(down_line_count, 0),
3025                Bias::Left,
3026            );
3027            end_point.column = excerpt.buffer.line_len(end_point.row);
3028            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3029            excerpt.max_buffer_row = end_point.row;
3030
3031            excerpt.text_summary = excerpt
3032                .buffer
3033                .text_summary_for_range(excerpt.range.context.clone());
3034
3035            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3036            let old_start_offset = cursor.start().1;
3037            let new_text_len = excerpt.text_summary.len;
3038            let edit = Edit {
3039                old: old_start_offset..old_start_offset + old_text_len,
3040                new: new_start_offset..new_start_offset + new_text_len,
3041            };
3042
3043            if let Some(last_edit) = edits.last_mut() {
3044                if last_edit.old.end == edit.old.start {
3045                    last_edit.old.end = edit.old.end;
3046                    last_edit.new.end = edit.new.end;
3047                } else {
3048                    edits.push(edit);
3049                }
3050            } else {
3051                edits.push(edit);
3052            }
3053
3054            new_excerpts.push(excerpt, ());
3055
3056            cursor.next();
3057        }
3058
3059        new_excerpts.append(cursor.suffix(), ());
3060
3061        drop(cursor);
3062        snapshot.excerpts = new_excerpts;
3063
3064        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3065        if !edits.is_empty() {
3066            self.subscriptions.publish(edits);
3067        }
3068        cx.emit(Event::Edited {
3069            edited_buffer: None,
3070        });
3071        cx.emit(Event::ExcerptsExpanded { ids });
3072        cx.notify();
3073    }
3074
3075    #[ztracing::instrument(skip_all)]
3076    fn sync(&self, cx: &App) {
3077        let changed = self.buffer_changed_since_sync.replace(false);
3078        if !changed {
3079            return;
3080        }
3081        let edits = Self::sync_from_buffer_changes(
3082            &mut self.snapshot.borrow_mut(),
3083            &self.buffers,
3084            &self.diffs,
3085            cx,
3086        );
3087        if !edits.is_empty() {
3088            self.subscriptions.publish(edits);
3089        }
3090    }
3091
3092    fn sync_mut(&mut self, cx: &App) {
3093        let changed = self.buffer_changed_since_sync.replace(false);
3094        if !changed {
3095            return;
3096        }
3097        let edits =
3098            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3099
3100        if !edits.is_empty() {
3101            self.subscriptions.publish(edits);
3102        }
3103    }
3104
3105    fn sync_from_buffer_changes(
3106        snapshot: &mut MultiBufferSnapshot,
3107        buffers: &BTreeMap<BufferId, BufferState>,
3108        diffs: &HashMap<BufferId, DiffState>,
3109        cx: &App,
3110    ) -> Vec<Edit<MultiBufferOffset>> {
3111        let MultiBufferSnapshot {
3112            excerpts,
3113            buffer_locators: _,
3114            diffs: buffer_diff,
3115            diff_transforms: _,
3116            non_text_state_update_count,
3117            edit_count,
3118            is_dirty,
3119            has_deleted_file,
3120            has_conflict,
3121            has_inverted_diff: _,
3122            singleton: _,
3123            excerpt_ids: _,
3124            replaced_excerpts: _,
3125            trailing_excerpt_update_count: _,
3126            all_diff_hunks_expanded: _,
3127            show_deleted_hunks: _,
3128            use_extended_diff_range: _,
3129            show_headers: _,
3130        } = snapshot;
3131        *is_dirty = false;
3132        *has_deleted_file = false;
3133        *has_conflict = false;
3134
3135        if !diffs.is_empty() {
3136            let mut diffs_to_add = Vec::new();
3137            for (id, diff) in diffs {
3138                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3139                // and use the diff hunk base text ranges to compute diff transforms.
3140                // Those base text ranges are usize, so make sure if the base text changed
3141                // we also update the diff snapshot so that we don't use stale offsets
3142                if buffer_diff.get(id).is_none_or(|existing_diff| {
3143                    if existing_diff.main_buffer.is_none() {
3144                        return false;
3145                    }
3146                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3147                    base_text.remote_id() != existing_diff.base_text().remote_id()
3148                        || base_text
3149                            .version()
3150                            .changed_since(existing_diff.base_text().version())
3151                }) {
3152                    if diffs_to_add.capacity() == 0 {
3153                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3154                        // meaning re-allocations will be fairly expensive
3155                        diffs_to_add.reserve(diffs.len());
3156                    }
3157                    diffs_to_add.push((*id, diff.snapshot(cx)));
3158                }
3159            }
3160            buffer_diff.extend(diffs_to_add);
3161        }
3162
3163        let mut excerpts_to_edit = Vec::new();
3164        let mut non_text_state_updated = false;
3165        let mut edited = false;
3166        for buffer_state in buffers.values() {
3167            let buffer = buffer_state.buffer.read(cx);
3168            let version = buffer.version();
3169            let non_text_state_update_count = buffer.non_text_state_update_count();
3170
3171            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3172            let buffer_non_text_state_updated =
3173                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3174            if buffer_edited || buffer_non_text_state_updated {
3175                *buffer_state.last_version.borrow_mut() = version;
3176                buffer_state
3177                    .last_non_text_state_update_count
3178                    .set(non_text_state_update_count);
3179                excerpts_to_edit.extend(
3180                    buffer_state
3181                        .excerpts
3182                        .iter()
3183                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3184                );
3185            }
3186
3187            edited |= buffer_edited;
3188            non_text_state_updated |= buffer_non_text_state_updated;
3189            *is_dirty |= buffer.is_dirty();
3190            *has_deleted_file |= buffer
3191                .file()
3192                .is_some_and(|file| file.disk_state().is_deleted());
3193            *has_conflict |= buffer.has_conflict();
3194        }
3195        if edited {
3196            *edit_count += 1;
3197        }
3198        if non_text_state_updated {
3199            *non_text_state_update_count += 1;
3200        }
3201
3202        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3203
3204        let mut edits = Vec::new();
3205        let mut new_excerpts = SumTree::default();
3206        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3207
3208        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3209            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3210            let old_excerpt = cursor.item().unwrap();
3211            let buffer = buffer.read(cx);
3212            let buffer_id = buffer.remote_id();
3213            let mut new_excerpt;
3214            if buffer_edited {
3215                edits.extend(
3216                    buffer
3217                        .edits_since_in_range::<usize>(
3218                            old_excerpt.buffer.version(),
3219                            old_excerpt.range.context.clone(),
3220                        )
3221                        .map(|edit| {
3222                            let excerpt_old_start = cursor.start().1;
3223                            let excerpt_new_start =
3224                                ExcerptDimension(new_excerpts.summary().text.len);
3225                            let old_start = excerpt_old_start + edit.old.start;
3226                            let old_end = excerpt_old_start + edit.old.end;
3227                            let new_start = excerpt_new_start + edit.new.start;
3228                            let new_end = excerpt_new_start + edit.new.end;
3229                            Edit {
3230                                old: old_start..old_end,
3231                                new: new_start..new_end,
3232                            }
3233                        }),
3234                );
3235
3236                new_excerpt = Excerpt::new(
3237                    old_excerpt.id,
3238                    locator.clone(),
3239                    buffer_id,
3240                    Arc::new(buffer.snapshot()),
3241                    old_excerpt.range.clone(),
3242                    old_excerpt.has_trailing_newline,
3243                );
3244            } else {
3245                new_excerpt = old_excerpt.clone();
3246                new_excerpt.buffer = Arc::new(buffer.snapshot());
3247            }
3248
3249            new_excerpts.push(new_excerpt, ());
3250            cursor.next();
3251        }
3252        new_excerpts.append(cursor.suffix(), ());
3253
3254        drop(cursor);
3255        *excerpts = new_excerpts;
3256
3257        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3258    }
3259
3260    fn sync_diff_transforms(
3261        snapshot: &mut MultiBufferSnapshot,
3262        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3263        change_kind: DiffChangeKind,
3264    ) -> Vec<Edit<MultiBufferOffset>> {
3265        if excerpt_edits.is_empty() {
3266            return vec![];
3267        }
3268
3269        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3270        let mut old_diff_transforms = snapshot
3271            .diff_transforms
3272            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3273        let mut new_diff_transforms = SumTree::default();
3274        let mut old_expanded_hunks = HashSet::default();
3275        let mut output_edits = Vec::new();
3276        let mut output_delta = 0_isize;
3277        let mut at_transform_boundary = true;
3278        let mut end_of_current_insert = None;
3279
3280        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3281        while let Some(edit) = excerpt_edits.next() {
3282            excerpts.seek_forward(&edit.new.start, Bias::Right);
3283            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3284                excerpts.prev();
3285            }
3286
3287            // Keep any transforms that are before the edit.
3288            if at_transform_boundary {
3289                at_transform_boundary = false;
3290                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3291                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3292                if let Some(transform) = old_diff_transforms.item()
3293                    && old_diff_transforms.end().0 == edit.old.start
3294                    && old_diff_transforms.start().0 < edit.old.start
3295                {
3296                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3297                    old_diff_transforms.next();
3298                }
3299            }
3300
3301            // Compute the start of the edit in output coordinates.
3302            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3303            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3304            let edit_new_start =
3305                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3306
3307            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3308                &edit,
3309                &mut excerpts,
3310                &mut old_diff_transforms,
3311                &mut new_diff_transforms,
3312                &mut end_of_current_insert,
3313                &mut old_expanded_hunks,
3314                snapshot,
3315                change_kind,
3316            );
3317
3318            // Compute the end of the edit in output coordinates.
3319            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3320            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3321            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3322            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3323            let output_edit = Edit {
3324                old: edit_old_start..edit_old_end,
3325                new: edit_new_start..edit_new_end,
3326            };
3327
3328            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3329            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3330            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3331                output_edits.push(output_edit);
3332            }
3333
3334            // If this is the last edit that intersects the current diff transform,
3335            // then recreate the content up to the end of this transform, to prepare
3336            // for reusing additional slices of the old transforms.
3337            if excerpt_edits
3338                .peek()
3339                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3340            {
3341                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3342                    && match old_diff_transforms.item() {
3343                        Some(DiffTransform::BufferContent {
3344                            inserted_hunk_info: Some(hunk),
3345                            ..
3346                        }) => excerpts.item().is_some_and(|excerpt| {
3347                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3348                                && diff.main_buffer.is_some()
3349                            {
3350                                return true;
3351                            }
3352                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3353                        }),
3354                        _ => true,
3355                    };
3356
3357                let mut excerpt_offset = edit.new.end;
3358                if !keep_next_old_transform {
3359                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3360                    old_diff_transforms.next();
3361                }
3362
3363                old_expanded_hunks.clear();
3364                Self::push_buffer_content_transform(
3365                    snapshot,
3366                    &mut new_diff_transforms,
3367                    excerpt_offset,
3368                    end_of_current_insert,
3369                );
3370                at_transform_boundary = true;
3371            }
3372        }
3373
3374        // Keep any transforms that are after the last edit.
3375        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3376
3377        // Ensure there's always at least one buffer content transform.
3378        if new_diff_transforms.is_empty() {
3379            new_diff_transforms.push(
3380                DiffTransform::BufferContent {
3381                    summary: Default::default(),
3382                    inserted_hunk_info: None,
3383                },
3384                (),
3385            );
3386        }
3387
3388        drop(old_diff_transforms);
3389        drop(excerpts);
3390        snapshot.diff_transforms = new_diff_transforms;
3391        snapshot.edit_count += 1;
3392
3393        #[cfg(any(test, feature = "test-support"))]
3394        snapshot.check_invariants();
3395        output_edits
3396    }
3397
3398    fn recompute_diff_transforms_for_edit(
3399        edit: &Edit<ExcerptOffset>,
3400        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3401        old_diff_transforms: &mut Cursor<
3402            DiffTransform,
3403            Dimensions<ExcerptOffset, MultiBufferOffset>,
3404        >,
3405        new_diff_transforms: &mut SumTree<DiffTransform>,
3406        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3407        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3408        snapshot: &MultiBufferSnapshot,
3409        change_kind: DiffChangeKind,
3410    ) -> bool {
3411        log::trace!(
3412            "recomputing diff transform for edit {:?} => {:?}",
3413            edit.old.start..edit.old.end,
3414            edit.new.start..edit.new.end
3415        );
3416
3417        // Record which hunks were previously expanded.
3418        while let Some(item) = old_diff_transforms.item() {
3419            if let Some(hunk_info) = item.hunk_info() {
3420                log::trace!(
3421                    "previously expanded hunk at {:?}",
3422                    old_diff_transforms.start()
3423                );
3424                old_expanded_hunks.insert(hunk_info);
3425            }
3426            if old_diff_transforms.end().0 > edit.old.end {
3427                break;
3428            }
3429            old_diff_transforms.next();
3430        }
3431
3432        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3433        // For inverted diffs, hunks are always shown, so we can't skip this.
3434        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3435        if old_expanded_hunks.is_empty()
3436            && change_kind == DiffChangeKind::BufferEdited
3437            && !all_diff_hunks_expanded
3438            && !snapshot.has_inverted_diff
3439        {
3440            return false;
3441        }
3442
3443        // Visit each excerpt that intersects the edit.
3444        let mut did_expand_hunks = false;
3445        while let Some(excerpt) = excerpts.item() {
3446            // Recompute the expanded hunks in the portion of the excerpt that
3447            // intersects the edit.
3448            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3449                let buffer = &excerpt.buffer;
3450                let excerpt_start = *excerpts.start();
3451                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3452                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3453                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3454                let edit_buffer_start =
3455                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3456                let edit_buffer_end =
3457                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3458                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3459
3460                if let Some(main_buffer) = &diff.main_buffer {
3461                    for hunk in diff.hunks_intersecting_base_text_range(
3462                        edit_buffer_start..edit_buffer_end,
3463                        main_buffer,
3464                    ) {
3465                        did_expand_hunks = true;
3466                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3467                        if hunk_buffer_range.start < excerpt_buffer_start {
3468                            log::trace!("skipping hunk that starts before excerpt");
3469                            continue;
3470                        }
3471                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3472                        let hunk_excerpt_start = excerpt_start
3473                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3474                        let hunk_excerpt_end = excerpt_end
3475                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3476                        Self::push_buffer_content_transform(
3477                            snapshot,
3478                            new_diff_transforms,
3479                            hunk_excerpt_start,
3480                            *end_of_current_insert,
3481                        );
3482                        if !hunk_buffer_range.is_empty() {
3483                            let hunk_info = DiffTransformHunkInfo {
3484                                excerpt_id: excerpt.id,
3485                                hunk_start_anchor: hunk.buffer_range.start,
3486                                hunk_secondary_status: hunk.secondary_status,
3487                                is_logically_deleted: true,
3488                            };
3489                            *end_of_current_insert =
3490                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3491                        }
3492                    }
3493                } else {
3494                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3495                        ..buffer.anchor_after(edit_buffer_end);
3496                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3497                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3498                            continue;
3499                        }
3500
3501                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3502                        if hunk_buffer_range.start < excerpt_buffer_start {
3503                            log::trace!("skipping hunk that starts before excerpt");
3504                            continue;
3505                        }
3506
3507                        let hunk_info = DiffTransformHunkInfo {
3508                            excerpt_id: excerpt.id,
3509                            hunk_start_anchor: hunk.buffer_range.start,
3510                            hunk_secondary_status: hunk.secondary_status,
3511                            is_logically_deleted: false,
3512                        };
3513
3514                        let hunk_excerpt_start = excerpt_start
3515                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3516                        let hunk_excerpt_end = excerpt_end
3517                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3518
3519                        Self::push_buffer_content_transform(
3520                            snapshot,
3521                            new_diff_transforms,
3522                            hunk_excerpt_start,
3523                            *end_of_current_insert,
3524                        );
3525
3526                        // For every existing hunk, determine if it was previously expanded
3527                        // and if it should currently be expanded.
3528                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3529                        let should_expand_hunk = match &change_kind {
3530                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3531                                was_previously_expanded || all_diff_hunks_expanded
3532                            }
3533                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3534                                let intersects = hunk_buffer_range.is_empty()
3535                                    || hunk_buffer_range.end > edit_buffer_start;
3536                                if *expand {
3537                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3538                                } else {
3539                                    !intersects
3540                                        && (was_previously_expanded || all_diff_hunks_expanded)
3541                                }
3542                            }
3543                            _ => was_previously_expanded || all_diff_hunks_expanded,
3544                        };
3545
3546                        if should_expand_hunk {
3547                            did_expand_hunks = true;
3548                            log::trace!(
3549                                "expanding hunk {:?}, excerpt:{:?}",
3550                                hunk_excerpt_start..hunk_excerpt_end,
3551                                excerpt.id
3552                            );
3553
3554                            if !hunk.diff_base_byte_range.is_empty()
3555                                && hunk_buffer_range.start >= edit_buffer_start
3556                                && hunk_buffer_range.start <= excerpt_buffer_end
3557                                && snapshot.show_deleted_hunks
3558                            {
3559                                let base_text = diff.base_text();
3560                                let mut text_cursor =
3561                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3562                                let mut base_text_summary = text_cursor
3563                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3564
3565                                let mut has_trailing_newline = false;
3566                                if base_text_summary.last_line_chars > 0 {
3567                                    base_text_summary += TextSummary::newline();
3568                                    has_trailing_newline = true;
3569                                }
3570
3571                                new_diff_transforms.push(
3572                                    DiffTransform::DeletedHunk {
3573                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3574                                        summary: base_text_summary,
3575                                        buffer_id: excerpt.buffer_id,
3576                                        hunk_info,
3577                                        has_trailing_newline,
3578                                    },
3579                                    (),
3580                                );
3581                            }
3582
3583                            if !hunk_buffer_range.is_empty() {
3584                                *end_of_current_insert =
3585                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3586                            }
3587                        }
3588                    }
3589                }
3590            }
3591
3592            if excerpts.end() <= edit.new.end {
3593                excerpts.next();
3594            } else {
3595                break;
3596            }
3597        }
3598
3599        did_expand_hunks || !old_expanded_hunks.is_empty()
3600    }
3601
3602    fn append_diff_transforms(
3603        new_transforms: &mut SumTree<DiffTransform>,
3604        subtree: SumTree<DiffTransform>,
3605    ) {
3606        if let Some(DiffTransform::BufferContent {
3607            inserted_hunk_info,
3608            summary,
3609        }) = subtree.first()
3610            && Self::extend_last_buffer_content_transform(
3611                new_transforms,
3612                *inserted_hunk_info,
3613                *summary,
3614            )
3615        {
3616            let mut cursor = subtree.cursor::<()>(());
3617            cursor.next();
3618            cursor.next();
3619            new_transforms.append(cursor.suffix(), ());
3620            return;
3621        }
3622        new_transforms.append(subtree, ());
3623    }
3624
3625    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3626        if let DiffTransform::BufferContent {
3627            inserted_hunk_info: inserted_hunk_anchor,
3628            summary,
3629        } = transform
3630            && Self::extend_last_buffer_content_transform(
3631                new_transforms,
3632                inserted_hunk_anchor,
3633                summary,
3634            )
3635        {
3636            return;
3637        }
3638        new_transforms.push(transform, ());
3639    }
3640
3641    fn push_buffer_content_transform(
3642        old_snapshot: &MultiBufferSnapshot,
3643        new_transforms: &mut SumTree<DiffTransform>,
3644        end_offset: ExcerptOffset,
3645        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3646    ) {
3647        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3648            (end_offset.min(insertion_end_offset), Some(hunk_info))
3649        });
3650        let unchanged_region = [(end_offset, None)];
3651
3652        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3653        {
3654            let start_offset = new_transforms.summary().excerpt_len();
3655            if end_offset <= start_offset {
3656                continue;
3657            }
3658            let summary_to_add = old_snapshot
3659                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3660
3661            if !Self::extend_last_buffer_content_transform(
3662                new_transforms,
3663                inserted_hunk_info,
3664                summary_to_add,
3665            ) {
3666                new_transforms.push(
3667                    DiffTransform::BufferContent {
3668                        summary: summary_to_add,
3669                        inserted_hunk_info,
3670                    },
3671                    (),
3672                )
3673            }
3674        }
3675    }
3676
3677    fn extend_last_buffer_content_transform(
3678        new_transforms: &mut SumTree<DiffTransform>,
3679        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3680        summary_to_add: MBTextSummary,
3681    ) -> bool {
3682        let mut did_extend = false;
3683        new_transforms.update_last(
3684            |last_transform| {
3685                if let DiffTransform::BufferContent {
3686                    summary,
3687                    inserted_hunk_info: inserted_hunk_anchor,
3688                } = last_transform
3689                    && *inserted_hunk_anchor == new_inserted_hunk_info
3690                {
3691                    *summary += summary_to_add;
3692                    did_extend = true;
3693                }
3694            },
3695            (),
3696        );
3697        did_extend
3698    }
3699
3700    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3701        let snapshot = self.snapshot(cx);
3702        let excerpt_id = range.end.excerpt_id;
3703        let point_range = range.to_point(&snapshot);
3704        let expand = !self.single_hunk_is_expanded(range, cx);
3705        let edits =
3706            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3707        if !edits.is_empty() {
3708            self.subscriptions.publish(edits);
3709        }
3710        cx.emit(Event::DiffHunksToggled);
3711        cx.emit(Event::Edited {
3712            edited_buffer: None,
3713        });
3714    }
3715}
3716
3717fn build_excerpt_ranges(
3718    ranges: impl IntoIterator<Item = Range<Point>>,
3719    context_line_count: u32,
3720    buffer_snapshot: &BufferSnapshot,
3721) -> Vec<ExcerptRange<Point>> {
3722    ranges
3723        .into_iter()
3724        .map(|range| {
3725            let start_row = range.start.row.saturating_sub(context_line_count);
3726            let start = Point::new(start_row, 0);
3727            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3728            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3729            ExcerptRange {
3730                context: start..end,
3731                primary: range,
3732            }
3733        })
3734        .collect()
3735}
3736
3737#[cfg(any(test, feature = "test-support"))]
3738impl MultiBuffer {
3739    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3740        let buffer = cx.new(|cx| Buffer::local(text, cx));
3741        cx.new(|cx| Self::singleton(buffer, cx))
3742    }
3743
3744    pub fn build_multi<const COUNT: usize>(
3745        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3746        cx: &mut gpui::App,
3747    ) -> Entity<Self> {
3748        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3749        for (text, ranges) in excerpts {
3750            let buffer = cx.new(|cx| Buffer::local(text, cx));
3751            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3752            multi.update(cx, |multi, cx| {
3753                multi.push_excerpts(buffer, excerpt_ranges, cx)
3754            });
3755        }
3756
3757        multi
3758    }
3759
3760    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3761        cx.new(|cx| Self::singleton(buffer, cx))
3762    }
3763
3764    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3765        cx.new(|cx| {
3766            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3767            let mutation_count = rng.random_range(1..=5);
3768            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3769            multibuffer
3770        })
3771    }
3772
3773    pub fn randomly_edit(
3774        &mut self,
3775        rng: &mut impl rand::Rng,
3776        edit_count: usize,
3777        cx: &mut Context<Self>,
3778    ) {
3779        use util::RandomCharIter;
3780
3781        let snapshot = self.read(cx);
3782        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3783        let mut last_end = None;
3784        for _ in 0..edit_count {
3785            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3786                break;
3787            }
3788
3789            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3790            let end =
3791                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3792            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3793            last_end = Some(end);
3794
3795            let mut range = start..end;
3796            if rng.random_bool(0.2) {
3797                mem::swap(&mut range.start, &mut range.end);
3798            }
3799
3800            let new_text_len = rng.random_range(0..10);
3801            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3802
3803            edits.push((range, new_text.into()));
3804        }
3805        log::info!("mutating multi-buffer with {:?}", edits);
3806        drop(snapshot);
3807
3808        self.edit(edits, None, cx);
3809    }
3810
3811    pub fn randomly_edit_excerpts(
3812        &mut self,
3813        rng: &mut impl rand::Rng,
3814        mutation_count: usize,
3815        cx: &mut Context<Self>,
3816    ) {
3817        use rand::prelude::*;
3818        use std::env;
3819        use util::RandomCharIter;
3820
3821        let max_excerpts = env::var("MAX_EXCERPTS")
3822            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3823            .unwrap_or(5);
3824
3825        let mut buffers = Vec::new();
3826        for _ in 0..mutation_count {
3827            if rng.random_bool(0.05) {
3828                log::info!("Clearing multi-buffer");
3829                self.clear(cx);
3830                continue;
3831            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3832                let ids = self.excerpt_ids();
3833                let mut excerpts = HashSet::default();
3834                for _ in 0..rng.random_range(0..ids.len()) {
3835                    excerpts.extend(ids.choose(rng).copied());
3836                }
3837
3838                let line_count = rng.random_range(0..5);
3839
3840                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3841
3842                self.expand_excerpts(
3843                    excerpts.iter().cloned(),
3844                    line_count,
3845                    ExpandExcerptDirection::UpAndDown,
3846                    cx,
3847                );
3848                continue;
3849            }
3850
3851            let excerpt_ids = self.excerpt_ids();
3852            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3853                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3854                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3855                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3856                    let buffer = buffers.last().unwrap().read(cx);
3857                    log::info!(
3858                        "Creating new buffer {} with text: {:?}",
3859                        buffer.remote_id(),
3860                        buffer.text()
3861                    );
3862                    buffers.last().unwrap().clone()
3863                } else {
3864                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3865                };
3866
3867                let buffer = buffer_handle.read(cx);
3868                let buffer_text = buffer.text();
3869                let ranges = (0..rng.random_range(0..5))
3870                    .map(|_| {
3871                        let end_ix =
3872                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3873                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3874                        ExcerptRange::new(start_ix..end_ix)
3875                    })
3876                    .collect::<Vec<_>>();
3877                log::info!(
3878                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3879                    buffer_handle.read(cx).remote_id(),
3880                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3881                    ranges
3882                        .iter()
3883                        .map(|r| &buffer_text[r.context.clone()])
3884                        .collect::<Vec<_>>()
3885                );
3886
3887                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3888                log::info!("Inserted with ids: {:?}", excerpt_id);
3889            } else {
3890                let remove_count = rng.random_range(1..=excerpt_ids.len());
3891                let mut excerpts_to_remove = excerpt_ids
3892                    .choose_multiple(rng, remove_count)
3893                    .cloned()
3894                    .collect::<Vec<_>>();
3895                let snapshot = self.snapshot.borrow();
3896                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3897                drop(snapshot);
3898                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3899                self.remove_excerpts(excerpts_to_remove, cx);
3900            }
3901        }
3902    }
3903
3904    pub fn randomly_mutate(
3905        &mut self,
3906        rng: &mut impl rand::Rng,
3907        mutation_count: usize,
3908        cx: &mut Context<Self>,
3909    ) {
3910        use rand::prelude::*;
3911
3912        if rng.random_bool(0.7) || self.singleton {
3913            let buffer = self
3914                .buffers
3915                .values()
3916                .choose(rng)
3917                .map(|state| state.buffer.clone());
3918
3919            if let Some(buffer) = buffer {
3920                buffer.update(cx, |buffer, cx| {
3921                    if rng.random() {
3922                        buffer.randomly_edit(rng, mutation_count, cx);
3923                    } else {
3924                        buffer.randomly_undo_redo(rng, cx);
3925                    }
3926                });
3927            } else {
3928                self.randomly_edit(rng, mutation_count, cx);
3929            }
3930        } else {
3931            self.randomly_edit_excerpts(rng, mutation_count, cx);
3932        }
3933
3934        self.check_invariants(cx);
3935    }
3936
3937    fn check_invariants(&self, cx: &App) {
3938        self.read(cx).check_invariants();
3939    }
3940}
3941
3942impl EventEmitter<Event> for MultiBuffer {}
3943
3944impl MultiBufferSnapshot {
3945    pub fn text(&self) -> String {
3946        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3947            .map(|chunk| chunk.text)
3948            .collect()
3949    }
3950
3951    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3952        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3953            .flat_map(|c| c.chars().rev())
3954    }
3955
3956    fn reversed_chunks_in_range(
3957        &self,
3958        range: Range<MultiBufferOffset>,
3959    ) -> ReversedMultiBufferChunks<'_> {
3960        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3961        cursor.seek(&range.end);
3962        let current_chunks = cursor.region().as_ref().map(|region| {
3963            let start_overshoot = range.start.saturating_sub(region.range.start);
3964            let end_overshoot = range.end - region.range.start;
3965            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3966            let start = region.buffer_range.start + start_overshoot;
3967            region.buffer.reversed_chunks_in_range(start..end)
3968        });
3969        ReversedMultiBufferChunks {
3970            cursor,
3971            current_chunks,
3972            start: range.start,
3973            offset: range.end,
3974        }
3975    }
3976
3977    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3978        let offset = position.to_offset(self);
3979        self.text_for_range(offset..self.len())
3980            .flat_map(|chunk| chunk.chars())
3981    }
3982
3983    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3984        self.chunks(range, false).map(|chunk| chunk.text)
3985    }
3986
3987    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3988        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3989            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3990    }
3991
3992    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3993    where
3994        T: ToOffset,
3995    {
3996        let position = position.to_offset(self);
3997        position == self.clip_offset(position, Bias::Left)
3998            && self
3999                .bytes_in_range(position..self.len())
4000                .flatten()
4001                .copied()
4002                .take(needle.len())
4003                .eq(needle.bytes())
4004    }
4005
4006    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4007        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4008    }
4009
4010    pub fn diff_hunks_in_range<T: ToPoint>(
4011        &self,
4012        range: Range<T>,
4013    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4014        let query_range = range.start.to_point(self)..range.end.to_point(self);
4015        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4016            let diff = self.diffs.get(&buffer.remote_id())?;
4017            let iter = if let Some(main_buffer) = &diff.main_buffer {
4018                let buffer_start = buffer.point_to_offset(buffer_range.start);
4019                let buffer_end = buffer.point_to_offset(buffer_range.end);
4020                itertools::Either::Left(
4021                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4022                        .map(move |hunk| (hunk, buffer, true)),
4023                )
4024            } else {
4025                let buffer_start = buffer.anchor_before(buffer_range.start);
4026                let buffer_end = buffer.anchor_after(buffer_range.end);
4027                itertools::Either::Right(
4028                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4029                        .map(move |hunk| (hunk, buffer, false)),
4030                )
4031            };
4032            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4033                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4034                    return None;
4035                }
4036                let range = if is_inverted {
4037                    hunk.diff_base_byte_range.to_point(&buffer)
4038                } else {
4039                    hunk.range.clone()
4040                };
4041                Some((range, (hunk, is_inverted)))
4042            }))
4043        })
4044        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4045            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4046            {
4047                return None;
4048            }
4049            let end_row = if range.end.column == 0 {
4050                range.end.row
4051            } else {
4052                range.end.row + 1
4053            };
4054
4055            let word_diffs =
4056                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4057                    .then(|| {
4058                        let mut word_diffs = Vec::new();
4059
4060                        if self.show_deleted_hunks || is_inverted {
4061                            let hunk_start_offset = if is_inverted {
4062                                Anchor::in_buffer(
4063                                    excerpt.id,
4064                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4065                                )
4066                                .to_offset(self)
4067                            } else {
4068                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4069                                    .to_offset(self)
4070                            };
4071
4072                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4073                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4074                            }));
4075                        }
4076
4077                        if !is_inverted {
4078                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4079                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4080                            }));
4081                        }
4082                        word_diffs
4083                    })
4084                    .unwrap_or_default();
4085
4086            let buffer_range = if is_inverted {
4087                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4088                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4089            } else {
4090                hunk.buffer_range.clone()
4091            };
4092            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4093                DiffHunkStatusKind::Deleted
4094            } else if hunk.diff_base_byte_range.is_empty() {
4095                DiffHunkStatusKind::Added
4096            } else {
4097                DiffHunkStatusKind::Modified
4098            };
4099            Some(MultiBufferDiffHunk {
4100                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4101                buffer_id: excerpt.buffer_id,
4102                excerpt_id: excerpt.id,
4103                buffer_range,
4104                word_diffs,
4105                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4106                    ..BufferOffset(hunk.diff_base_byte_range.end),
4107                status: DiffHunkStatus {
4108                    kind: status_kind,
4109                    secondary: hunk.secondary_status,
4110                },
4111            })
4112        })
4113    }
4114
4115    fn excerpts_for_range<T: ToOffset>(
4116        &self,
4117        range: Range<T>,
4118    ) -> impl Iterator<Item = &Excerpt> + '_ {
4119        let range = range.start.to_offset(self)..range.end.to_offset(self);
4120        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4121        cursor.seek(&range.start);
4122        std::iter::from_fn(move || {
4123            let region = cursor.region()?;
4124            if region.range.start > range.end
4125                || region.range.start == range.end && region.range.start > range.start
4126            {
4127                return None;
4128            }
4129            let excerpt = region.excerpt;
4130            cursor.next_excerpt_forwards();
4131            Some(excerpt)
4132        })
4133    }
4134
4135    pub fn excerpt_ids_for_range<T: ToOffset>(
4136        &self,
4137        range: Range<T>,
4138    ) -> impl Iterator<Item = ExcerptId> + '_ {
4139        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4140    }
4141
4142    pub fn buffer_ids_for_range<T: ToOffset>(
4143        &self,
4144        range: Range<T>,
4145    ) -> impl Iterator<Item = BufferId> + '_ {
4146        self.excerpts_for_range(range)
4147            .map(|excerpt| excerpt.buffer_id)
4148    }
4149
4150    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4151    ///
4152    /// The passed in anchors must be ordered.
4153    pub fn text_anchors_to_visible_anchors(
4154        &self,
4155        anchors: impl IntoIterator<Item = text::Anchor>,
4156    ) -> Vec<Option<Anchor>> {
4157        let anchors = anchors.into_iter();
4158        let mut result = Vec::with_capacity(anchors.size_hint().0);
4159        let mut anchors = anchors.peekable();
4160        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4161        'anchors: while let Some(anchor) = anchors.peek() {
4162            let Some(buffer_id) = anchor.buffer_id else {
4163                anchors.next();
4164                result.push(None);
4165                continue 'anchors;
4166            };
4167            let mut same_buffer_anchors =
4168                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4169
4170            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4171                let Some(mut next) = same_buffer_anchors.next() else {
4172                    continue 'anchors;
4173                };
4174                'excerpts: for locator in locators.iter() {
4175                    if cursor.seek_forward(&Some(locator), Bias::Left)
4176                        && let Some(excerpt) = cursor.item()
4177                    {
4178                        loop {
4179                            // anchor is before the first excerpt
4180                            if excerpt
4181                                .range
4182                                .context
4183                                .start
4184                                .cmp(&next, &excerpt.buffer)
4185                                .is_gt()
4186                            {
4187                                // so we skip it and try the next anchor
4188                                result.push(None);
4189                                match same_buffer_anchors.next() {
4190                                    Some(anchor) => next = anchor,
4191                                    None => continue 'anchors,
4192                                }
4193                            // anchor is within the excerpt
4194                            } else if excerpt
4195                                .range
4196                                .context
4197                                .end
4198                                .cmp(&next, &excerpt.buffer)
4199                                .is_ge()
4200                            {
4201                                // record it and all following anchors that are within
4202                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4203                                result.extend(
4204                                    same_buffer_anchors
4205                                        .peeking_take_while(|a| {
4206                                            excerpt
4207                                                .range
4208                                                .context
4209                                                .end
4210                                                .cmp(a, &excerpt.buffer)
4211                                                .is_ge()
4212                                        })
4213                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4214                                );
4215                                match same_buffer_anchors.next() {
4216                                    Some(anchor) => next = anchor,
4217                                    None => continue 'anchors,
4218                                }
4219                            // anchor is after the excerpt, try the next one
4220                            } else {
4221                                continue 'excerpts;
4222                            }
4223                        }
4224                    }
4225                }
4226                // account for `next`
4227                result.push(None);
4228            }
4229            result.extend(same_buffer_anchors.map(|_| None));
4230        }
4231
4232        result
4233    }
4234
4235    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4236        &self,
4237        ranges: impl Iterator<Item = Range<T>>,
4238    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4239        ranges.flat_map(|range| {
4240            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4241                .into_iter()
4242        })
4243    }
4244
4245    pub fn range_to_buffer_ranges<R, T>(
4246        &self,
4247        range: R,
4248    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4249    where
4250        R: RangeBounds<T>,
4251        T: ToOffset,
4252    {
4253        self.range_to_buffer_ranges_with_context(range)
4254            .into_iter()
4255            .map(|(buffer, range, id, _context)| (buffer, range, id))
4256            .collect()
4257    }
4258
4259    pub fn range_to_buffer_ranges_with_context<R, T>(
4260        &self,
4261        range: R,
4262    ) -> Vec<(
4263        &BufferSnapshot,
4264        Range<BufferOffset>,
4265        ExcerptId,
4266        Range<text::Anchor>,
4267    )>
4268    where
4269        R: RangeBounds<T>,
4270        T: ToOffset,
4271    {
4272        let start = match range.start_bound() {
4273            Bound::Included(start) => start.to_offset(self),
4274            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4275            Bound::Unbounded => MultiBufferOffset::ZERO,
4276        };
4277        let end_bound = match range.end_bound() {
4278            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4279            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4280            Bound::Unbounded => Bound::Unbounded,
4281        };
4282        let bounds = (Bound::Included(start), end_bound);
4283
4284        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4285        cursor.seek(&start);
4286
4287        let mut result: Vec<(
4288            &BufferSnapshot,
4289            Range<BufferOffset>,
4290            ExcerptId,
4291            Range<text::Anchor>,
4292        )> = Vec::new();
4293        while let Some(region) = cursor.region() {
4294            let dominated_by_end_bound = match end_bound {
4295                Bound::Included(end) => region.range.start > end,
4296                Bound::Excluded(end) => region.range.start >= end,
4297                Bound::Unbounded => false,
4298            };
4299            if dominated_by_end_bound {
4300                break;
4301            }
4302            if region.is_main_buffer {
4303                let start_overshoot = start.saturating_sub(region.range.start);
4304                let end_offset = match end_bound {
4305                    Bound::Included(end) | Bound::Excluded(end) => end,
4306                    Bound::Unbounded => region.range.end,
4307                };
4308                let end_overshoot = end_offset.saturating_sub(region.range.start);
4309                let start = region
4310                    .buffer_range
4311                    .end
4312                    .min(region.buffer_range.start + start_overshoot);
4313                let end = region
4314                    .buffer_range
4315                    .end
4316                    .min(region.buffer_range.start + end_overshoot);
4317                let context = region.excerpt.range.context.clone();
4318                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4319                    *excerpt_id == region.excerpt.id && prev_range.end == start
4320                }) {
4321                    prev.1.end = end;
4322                } else {
4323                    result.push((region.buffer, start..end, region.excerpt.id, context));
4324                }
4325            }
4326            cursor.next();
4327        }
4328
4329        if let Some(excerpt) = cursor.excerpt() {
4330            let dominated_by_prev_excerpt =
4331                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4332            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4333                let excerpt_position = self.len();
4334                if bounds.contains(&excerpt_position) {
4335                    let buffer_offset =
4336                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4337                    let context = excerpt.range.context.clone();
4338                    result.push((
4339                        &excerpt.buffer,
4340                        buffer_offset..buffer_offset,
4341                        excerpt.id,
4342                        context,
4343                    ));
4344                }
4345            }
4346        }
4347
4348        result
4349    }
4350
4351    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4352        &self,
4353        range: Range<T>,
4354    ) -> impl Iterator<
4355        Item = (
4356            &BufferSnapshot,
4357            Range<BufferOffset>,
4358            ExcerptId,
4359            Option<Anchor>,
4360        ),
4361    > + '_ {
4362        let start = range.start.to_offset(self);
4363        let end = range.end.to_offset(self);
4364
4365        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4366        cursor.seek(&start);
4367
4368        std::iter::from_fn(move || {
4369            let region = cursor.region()?;
4370            if region.range.start > end {
4371                return None;
4372            }
4373            let start_overshoot = start.saturating_sub(region.range.start);
4374            let end_overshoot = end.saturating_sub(region.range.start);
4375            let start = region
4376                .buffer_range
4377                .end
4378                .min(region.buffer_range.start + start_overshoot);
4379            let end = region
4380                .buffer_range
4381                .end
4382                .min(region.buffer_range.start + end_overshoot);
4383
4384            let region_excerpt_id = region.excerpt.id;
4385            let deleted_hunk_anchor = if region.is_main_buffer {
4386                None
4387            } else {
4388                Some(self.anchor_before(region.range.start))
4389            };
4390            let result = (
4391                region.buffer,
4392                start..end,
4393                region_excerpt_id,
4394                deleted_hunk_anchor,
4395            );
4396            cursor.next();
4397            Some(result)
4398        })
4399    }
4400
4401    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4402    /// coordinates.
4403    ///
4404    /// The given callback will be called for every excerpt intersecting the given range. It will
4405    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4406    /// The callback should return an iterator of metadata items from that buffer, each paired
4407    /// with a buffer range.
4408    ///
4409    /// The returned iterator yields each of these metadata items, paired with its range in
4410    /// multi-buffer coordinates.
4411    fn lift_buffer_metadata<'a, MBD, M, I>(
4412        &'a self,
4413        query_range: Range<MBD>,
4414        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4415    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4416    where
4417        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4418        MBD: MultiBufferDimension
4419            + Ord
4420            + Sub<Output = MBD::TextDimension>
4421            + ops::Add<MBD::TextDimension, Output = MBD>
4422            + ops::AddAssign<MBD::TextDimension>,
4423        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4424            + ops::Add<Output = MBD::TextDimension>
4425            + AddAssign<MBD::TextDimension>
4426            + Ord,
4427    {
4428        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4429        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4430
4431        // Find the excerpt and buffer offset where the given range ends.
4432        cursor.seek(&query_range.end);
4433        let mut range_end = None;
4434        while let Some(region) = cursor.region() {
4435            if region.is_main_buffer {
4436                let mut buffer_end = region.buffer_range.start;
4437                let overshoot = if query_range.end > region.range.start {
4438                    query_range.end - region.range.start
4439                } else {
4440                    <MBD::TextDimension>::default()
4441                };
4442                buffer_end = buffer_end + overshoot;
4443                range_end = Some((region.excerpt.id, buffer_end));
4444                break;
4445            }
4446            cursor.next();
4447        }
4448
4449        cursor.seek(&query_range.start);
4450
4451        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4452            && region.range.start > MBD::default()
4453        {
4454            cursor.prev()
4455        } else if let Some(region) = cursor.region()
4456            && region.is_main_buffer
4457            && region.diff_hunk_status.is_some()
4458        {
4459            cursor.prev();
4460            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4461                cursor.next();
4462            }
4463        }
4464
4465        iter::from_fn(move || {
4466            loop {
4467                let excerpt = cursor.excerpt()?;
4468
4469                // If we have already retrieved metadata for this excerpt, continue to use it.
4470                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4471                    .as_mut()
4472                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4473                {
4474                    Some(metadata)
4475                }
4476                // Otherwise, compute the intersection of the input range with the excerpt's range,
4477                // and retrieve the metadata for the resulting range.
4478                else {
4479                    let region = cursor.region()?;
4480                    let mut buffer_start;
4481                    if region.is_main_buffer {
4482                        buffer_start = region.buffer_range.start;
4483                        if query_range.start > region.range.start {
4484                            let overshoot = query_range.start - region.range.start;
4485                            buffer_start = buffer_start + overshoot;
4486                        }
4487                        buffer_start = buffer_start.min(region.buffer_range.end);
4488                    } else {
4489                        buffer_start = cursor.main_buffer_position()?;
4490                    };
4491                    let mut buffer_end = excerpt
4492                        .range
4493                        .context
4494                        .end
4495                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4496                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4497                        && excerpt.id == end_excerpt_id
4498                    {
4499                        buffer_end = buffer_end.min(end_buffer_offset);
4500                    }
4501
4502                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4503                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4504                    })
4505                };
4506
4507                // Visit each metadata item.
4508                if let Some((metadata_buffer_range, metadata)) =
4509                    metadata_iter.and_then(Iterator::next)
4510                {
4511                    // Find the multibuffer regions that contain the start and end of
4512                    // the metadata item's range.
4513                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4514                        while let Some(region) = cursor.region() {
4515                            if (region.is_main_buffer
4516                                && (region.buffer_range.end >= metadata_buffer_range.start
4517                                    || cursor.is_at_end_of_excerpt()))
4518                                || (!region.is_main_buffer
4519                                    && region.buffer_range.start == metadata_buffer_range.start)
4520                            {
4521                                break;
4522                            }
4523                            cursor.next();
4524                        }
4525                    }
4526                    let start_region = cursor.region()?.clone();
4527                    while let Some(region) = cursor.region() {
4528                        if region.is_main_buffer
4529                            && (region.buffer_range.end > metadata_buffer_range.end
4530                                || cursor.is_at_end_of_excerpt())
4531                        {
4532                            break;
4533                        }
4534                        cursor.next();
4535                    }
4536                    let end_region = cursor.region();
4537
4538                    // Convert the metadata item's range into multibuffer coordinates.
4539                    let mut start_position = start_region.range.start;
4540                    let region_buffer_start = start_region.buffer_range.start;
4541                    if start_region.is_main_buffer
4542                        && metadata_buffer_range.start > region_buffer_start
4543                    {
4544                        start_position =
4545                            start_position + (metadata_buffer_range.start - region_buffer_start);
4546                        start_position = start_position.min(start_region.range.end);
4547                    }
4548
4549                    let mut end_position = self.max_position();
4550                    if let Some(end_region) = &end_region {
4551                        end_position = end_region.range.start;
4552                        debug_assert!(end_region.is_main_buffer);
4553                        let region_buffer_start = end_region.buffer_range.start;
4554                        if metadata_buffer_range.end > region_buffer_start {
4555                            end_position =
4556                                end_position + (metadata_buffer_range.end - region_buffer_start);
4557                        }
4558                        end_position = end_position.min(end_region.range.end);
4559                    }
4560
4561                    if start_position <= query_range.end && end_position >= query_range.start {
4562                        return Some((start_position..end_position, metadata, excerpt));
4563                    }
4564                }
4565                // When there are no more metadata items for this excerpt, move to the next excerpt.
4566                else {
4567                    current_excerpt_metadata.take();
4568                    if let Some((end_excerpt_id, _)) = range_end
4569                        && excerpt.id == end_excerpt_id
4570                    {
4571                        return None;
4572                    }
4573                    cursor.next_excerpt_forwards();
4574                }
4575            }
4576        })
4577    }
4578
4579    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4580        let offset = position.to_offset(self);
4581
4582        let mut cursor = self
4583            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4584            );
4585        cursor.seek(&DimensionPair {
4586            key: offset,
4587            value: None,
4588        });
4589        cursor.seek_to_start_of_current_excerpt();
4590        let excerpt = cursor.excerpt()?;
4591
4592        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4593        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4594        let current_position = self
4595            .anchor_before(offset)
4596            .text_anchor
4597            .to_offset(&excerpt.buffer);
4598
4599        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4600            if let Some(main_buffer) = &diff.main_buffer {
4601                for hunk in diff
4602                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4603                {
4604                    if hunk.diff_base_byte_range.end >= current_position {
4605                        continue;
4606                    }
4607                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4608                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4609                    return Some(MultiBufferRow(start.row));
4610                }
4611            } else {
4612                let excerpt_end = excerpt
4613                    .buffer
4614                    .anchor_before(excerpt_end.min(current_position));
4615                for hunk in diff.hunks_intersecting_range_rev(
4616                    excerpt.range.context.start..excerpt_end,
4617                    &excerpt.buffer,
4618                ) {
4619                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4620                    if hunk_end >= current_position {
4621                        continue;
4622                    }
4623                    let start =
4624                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4625                    return Some(MultiBufferRow(start.row));
4626                }
4627            }
4628        }
4629
4630        loop {
4631            cursor.prev_excerpt();
4632            let excerpt = cursor.excerpt()?;
4633
4634            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4635                continue;
4636            };
4637            if let Some(main_buffer) = &diff.main_buffer {
4638                let Some(hunk) = diff
4639                    .hunks_intersecting_base_text_range_rev(
4640                        excerpt.range.context.to_offset(&excerpt.buffer),
4641                        main_buffer,
4642                    )
4643                    .next()
4644                else {
4645                    continue;
4646                };
4647                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4648                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4649                return Some(MultiBufferRow(start.row));
4650            } else {
4651                let Some(hunk) = diff
4652                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4653                    .next()
4654                else {
4655                    continue;
4656                };
4657                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4658                return Some(MultiBufferRow(start.row));
4659            }
4660        }
4661    }
4662
4663    pub fn has_diff_hunks(&self) -> bool {
4664        self.diffs.values().any(|diff| !diff.is_empty())
4665    }
4666
4667    pub fn is_inside_word<T: ToOffset>(
4668        &self,
4669        position: T,
4670        scope_context: Option<CharScopeContext>,
4671    ) -> bool {
4672        let position = position.to_offset(self);
4673        let classifier = self
4674            .char_classifier_at(position)
4675            .scope_context(scope_context);
4676        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4677        let prev_char_kind = self
4678            .reversed_chars_at(position)
4679            .next()
4680            .map(|c| classifier.kind(c));
4681        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4682    }
4683
4684    pub fn surrounding_word<T: ToOffset>(
4685        &self,
4686        start: T,
4687        scope_context: Option<CharScopeContext>,
4688    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4689        let mut start = start.to_offset(self);
4690        let mut end = start;
4691        let mut next_chars = self.chars_at(start).peekable();
4692        let mut prev_chars = self.reversed_chars_at(start).peekable();
4693
4694        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4695
4696        let word_kind = cmp::max(
4697            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4698            next_chars.peek().copied().map(|c| classifier.kind(c)),
4699        );
4700
4701        for ch in prev_chars {
4702            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4703                start -= ch.len_utf8();
4704            } else {
4705                break;
4706            }
4707        }
4708
4709        for ch in next_chars {
4710            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4711                end += ch.len_utf8();
4712            } else {
4713                break;
4714            }
4715        }
4716
4717        (start..end, word_kind)
4718    }
4719
4720    pub fn char_kind_before<T: ToOffset>(
4721        &self,
4722        start: T,
4723        scope_context: Option<CharScopeContext>,
4724    ) -> Option<CharKind> {
4725        let start = start.to_offset(self);
4726        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4727        self.reversed_chars_at(start)
4728            .next()
4729            .map(|ch| classifier.kind(ch))
4730    }
4731
4732    pub fn is_singleton(&self) -> bool {
4733        self.singleton
4734    }
4735
4736    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4737        if self.singleton {
4738            self.excerpts
4739                .iter()
4740                .next()
4741                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4742        } else {
4743            None
4744        }
4745    }
4746
4747    pub fn len(&self) -> MultiBufferOffset {
4748        self.diff_transforms.summary().output.len
4749    }
4750
4751    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4752        MBD::from_summary(&self.text_summary())
4753    }
4754
4755    pub fn is_empty(&self) -> bool {
4756        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4757    }
4758
4759    pub fn widest_line_number(&self) -> u32 {
4760        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4761        self.excerpts.summary().widest_line_number + 1
4762    }
4763
4764    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4765        let range = range.start.to_offset(self)..range.end.to_offset(self);
4766        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4767        excerpts.seek(&range.start);
4768
4769        let mut chunk;
4770        let mut has_trailing_newline;
4771        let excerpt_bytes;
4772        if let Some(region) = excerpts.region() {
4773            let mut bytes = region.buffer.bytes_in_range(
4774                region.buffer_range.start + (range.start - region.range.start)
4775                    ..(region.buffer_range.start + (range.end - region.range.start))
4776                        .min(region.buffer_range.end),
4777            );
4778            chunk = bytes.next().unwrap_or(&[][..]);
4779            excerpt_bytes = Some(bytes);
4780            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4781            if chunk.is_empty() && has_trailing_newline {
4782                chunk = b"\n";
4783                has_trailing_newline = false;
4784            }
4785        } else {
4786            chunk = &[][..];
4787            excerpt_bytes = None;
4788            has_trailing_newline = false;
4789        };
4790
4791        MultiBufferBytes {
4792            range,
4793            cursor: excerpts,
4794            excerpt_bytes,
4795            has_trailing_newline,
4796            chunk,
4797        }
4798    }
4799
4800    pub fn reversed_bytes_in_range<T: ToOffset>(
4801        &self,
4802        range: Range<T>,
4803    ) -> ReversedMultiBufferBytes<'_> {
4804        let range = range.start.to_offset(self)..range.end.to_offset(self);
4805        let mut chunks = self.reversed_chunks_in_range(range.clone());
4806        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4807        ReversedMultiBufferBytes {
4808            range,
4809            chunks,
4810            chunk,
4811        }
4812    }
4813
4814    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4815        let mut cursor = self.cursor::<Point, Point>();
4816        cursor.seek(&Point::new(start_row.0, 0));
4817        let mut result = MultiBufferRows {
4818            point: Point::new(0, 0),
4819            is_empty: self.excerpts.is_empty(),
4820            is_singleton: self.is_singleton(),
4821            cursor,
4822        };
4823        result.seek(start_row);
4824        result
4825    }
4826
4827    pub fn chunks<T: ToOffset>(
4828        &self,
4829        range: Range<T>,
4830        language_aware: bool,
4831    ) -> MultiBufferChunks<'_> {
4832        let mut chunks = MultiBufferChunks {
4833            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4834                ..ExcerptDimension(MultiBufferOffset::ZERO),
4835            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4836            excerpts: self.excerpts.cursor(()),
4837            diff_transforms: self.diff_transforms.cursor(()),
4838            diffs: &self.diffs,
4839            diff_base_chunks: None,
4840            excerpt_chunks: None,
4841            buffer_chunk: None,
4842            language_aware,
4843        };
4844        let range = range.start.to_offset(self)..range.end.to_offset(self);
4845        chunks.seek(range);
4846        chunks
4847    }
4848
4849    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4850        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4851    }
4852
4853    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4854        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4855    }
4856
4857    pub fn clip_offset_utf16(
4858        &self,
4859        offset: MultiBufferOffsetUtf16,
4860        bias: Bias,
4861    ) -> MultiBufferOffsetUtf16 {
4862        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4863    }
4864
4865    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4866        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4867            buffer.clip_point_utf16(Unclipped(point), bias)
4868        })
4869    }
4870
4871    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4872        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4873    }
4874
4875    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4876        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4877    }
4878
4879    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4880        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4881    }
4882
4883    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4884        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4885    }
4886
4887    #[instrument(skip_all)]
4888    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4889        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4890    }
4891
4892    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4893        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4894    }
4895
4896    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4897        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4898    }
4899
4900    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4901        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4902    }
4903
4904    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4905        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4906    }
4907
4908    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4909        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4910    }
4911
4912    fn clip_dimension<MBD, BD>(
4913        &self,
4914        position: MBD,
4915        bias: Bias,
4916        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4917    ) -> MBD
4918    where
4919        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4920        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4921    {
4922        let mut cursor = self.cursor::<MBD, BD>();
4923        cursor.seek(&position);
4924        if let Some(region) = cursor.region() {
4925            if position >= region.range.end {
4926                return region.range.end;
4927            }
4928            let overshoot = position - region.range.start;
4929            let mut buffer_position = region.buffer_range.start;
4930            buffer_position += overshoot;
4931            let clipped_buffer_position =
4932                clip_buffer_position(region.buffer, buffer_position, bias);
4933            let mut position = region.range.start;
4934            position += clipped_buffer_position - region.buffer_range.start;
4935            position
4936        } else {
4937            self.max_position()
4938        }
4939    }
4940
4941    #[instrument(skip_all)]
4942    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4943        &self,
4944        key: MBR1,
4945        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4946    ) -> MBR2
4947    where
4948        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4949        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4950        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4951        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4952    {
4953        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4954        cursor.seek(&DimensionPair { key, value: None });
4955        if let Some(region) = cursor.region() {
4956            if key >= region.range.end.key {
4957                return region.range.end.value.unwrap();
4958            }
4959            let start_key = region.range.start.key;
4960            let start_value = region.range.start.value.unwrap();
4961            let buffer_start_key = region.buffer_range.start.key;
4962            let buffer_start_value = region.buffer_range.start.value.unwrap();
4963            let mut buffer_key = buffer_start_key;
4964            buffer_key += key - start_key;
4965            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4966            let mut result = start_value;
4967            result += buffer_value - buffer_start_value;
4968            result
4969        } else {
4970            self.max_position()
4971        }
4972    }
4973
4974    pub fn point_to_buffer_offset<T: ToOffset>(
4975        &self,
4976        point: T,
4977    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4978        let offset = point.to_offset(self);
4979        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4980        cursor.seek(&offset);
4981        let region = cursor.region()?;
4982        let overshoot = offset - region.range.start;
4983        let buffer_offset = region.buffer_range.start + overshoot;
4984        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4985            && region.has_trailing_newline
4986            && !region.is_main_buffer
4987        {
4988            let main_buffer_position = cursor.main_buffer_position()?;
4989            let buffer_snapshot = &cursor.excerpt()?.buffer;
4990            return Some((buffer_snapshot, main_buffer_position));
4991        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4992            return None;
4993        }
4994        Some((region.buffer, buffer_offset))
4995    }
4996
4997    pub fn point_to_buffer_point(
4998        &self,
4999        point: Point,
5000    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5001        let mut cursor = self.cursor::<Point, Point>();
5002        cursor.seek(&point);
5003        let region = cursor.region()?;
5004        let overshoot = point - region.range.start;
5005        let buffer_point = region.buffer_range.start + overshoot;
5006        let excerpt = cursor.excerpt()?;
5007        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5008            && region.has_trailing_newline
5009            && !region.is_main_buffer
5010        {
5011            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5012        } else if buffer_point > region.buffer.max_point() {
5013            return None;
5014        }
5015        Some((region.buffer, buffer_point, excerpt.id))
5016    }
5017
5018    pub fn suggested_indents(
5019        &self,
5020        rows: impl IntoIterator<Item = u32>,
5021        cx: &App,
5022    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5023        let mut result = BTreeMap::new();
5024        self.suggested_indents_callback(
5025            rows,
5026            &mut |row, indent| {
5027                result.insert(row, indent);
5028                ControlFlow::Continue(())
5029            },
5030            cx,
5031        );
5032        result
5033    }
5034
5035    // move this to be a generator once those are a thing
5036    pub fn suggested_indents_callback(
5037        &self,
5038        rows: impl IntoIterator<Item = u32>,
5039        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5040        cx: &App,
5041    ) {
5042        let mut rows_for_excerpt = Vec::new();
5043        let mut cursor = self.cursor::<Point, Point>();
5044        let mut rows = rows.into_iter().peekable();
5045        let mut prev_row = u32::MAX;
5046        let mut prev_language_indent_size = IndentSize::default();
5047
5048        while let Some(row) = rows.next() {
5049            cursor.seek(&Point::new(row, 0));
5050            let Some(region) = cursor.region() else {
5051                continue;
5052            };
5053
5054            // Retrieve the language and indent size once for each disjoint region being indented.
5055            let single_indent_size = if row.saturating_sub(1) == prev_row {
5056                prev_language_indent_size
5057            } else {
5058                region
5059                    .buffer
5060                    .language_indent_size_at(Point::new(row, 0), cx)
5061            };
5062            prev_language_indent_size = single_indent_size;
5063            prev_row = row;
5064
5065            let start_buffer_row = region.buffer_range.start.row;
5066            let start_multibuffer_row = region.range.start.row;
5067            let end_multibuffer_row = region.range.end.row;
5068
5069            rows_for_excerpt.push(row);
5070            while let Some(next_row) = rows.peek().copied() {
5071                if end_multibuffer_row > next_row {
5072                    rows_for_excerpt.push(next_row);
5073                    rows.next();
5074                } else {
5075                    break;
5076                }
5077            }
5078
5079            let buffer_rows = rows_for_excerpt
5080                .drain(..)
5081                .map(|row| start_buffer_row + row - start_multibuffer_row);
5082            let buffer_indents = region
5083                .buffer
5084                .suggested_indents(buffer_rows, single_indent_size);
5085            for (row, indent) in buffer_indents {
5086                if cb(
5087                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5088                    indent,
5089                )
5090                .is_break()
5091                {
5092                    return;
5093                }
5094            }
5095        }
5096    }
5097
5098    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5099        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5100            let mut size = buffer.indent_size_for_line(range.start.row);
5101            size.len = size
5102                .len
5103                .min(range.end.column)
5104                .saturating_sub(range.start.column);
5105            size
5106        } else {
5107            IndentSize::spaces(0)
5108        }
5109    }
5110
5111    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5112        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5113            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5114        } else {
5115            LineIndent::spaces(0)
5116        }
5117    }
5118
5119    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5120        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5121
5122        if self.language_settings(cx).extend_comment_on_newline
5123            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5124        {
5125            let delimiters = language_scope.line_comment_prefixes();
5126            for delimiter in delimiters {
5127                if *self
5128                    .chars_at(Point::new(row.0, indent.len() as u32))
5129                    .take(delimiter.chars().count())
5130                    .collect::<String>()
5131                    .as_str()
5132                    == **delimiter
5133                {
5134                    indent.push_str(delimiter);
5135                    break;
5136                }
5137            }
5138        }
5139
5140        indent
5141    }
5142
5143    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5144    where
5145        T: ToOffset,
5146    {
5147        for char in self.reversed_chars_at(position) {
5148            if !char.is_whitespace() {
5149                return false;
5150            }
5151            if char == '\n' {
5152                return true;
5153            }
5154        }
5155        true
5156    }
5157
5158    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5159        while row.0 > 0 {
5160            row.0 -= 1;
5161            if !self.is_line_blank(row) {
5162                return Some(row);
5163            }
5164        }
5165        None
5166    }
5167
5168    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5169        if let Some((_, range)) = self.buffer_line_for_row(row) {
5170            range.end.column - range.start.column
5171        } else {
5172            0
5173        }
5174    }
5175
5176    pub fn buffer_line_for_row(
5177        &self,
5178        row: MultiBufferRow,
5179    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5180        let mut cursor = self.cursor::<Point, Point>();
5181        let point = Point::new(row.0, 0);
5182        cursor.seek(&point);
5183        let region = cursor.region()?;
5184        let overshoot = point.min(region.range.end) - region.range.start;
5185        let buffer_point = region.buffer_range.start + overshoot;
5186        if buffer_point.row > region.buffer_range.end.row {
5187            return None;
5188        }
5189        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5190        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5191            .min(region.buffer_range.end);
5192        Some((region.buffer, line_start..line_end))
5193    }
5194
5195    pub fn max_point(&self) -> Point {
5196        self.text_summary().lines
5197    }
5198
5199    pub fn max_row(&self) -> MultiBufferRow {
5200        MultiBufferRow(self.text_summary().lines.row)
5201    }
5202
5203    pub fn text_summary(&self) -> MBTextSummary {
5204        self.diff_transforms.summary().output
5205    }
5206
5207    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5208    where
5209        MBD: MultiBufferDimension + AddAssign,
5210        O: ToOffset,
5211    {
5212        let range = range.start.to_offset(self)..range.end.to_offset(self);
5213        let mut cursor = self
5214            .diff_transforms
5215            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5216        cursor.seek(&range.start, Bias::Right);
5217
5218        let Some(first_transform) = cursor.item() else {
5219            return MBD::from_summary(&MBTextSummary::default());
5220        };
5221
5222        let diff_transform_start = cursor.start().0;
5223        let diff_transform_end = cursor.end().0;
5224        let diff_start = range.start;
5225        let start_overshoot = diff_start - diff_transform_start;
5226        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5227
5228        let mut result = match first_transform {
5229            DiffTransform::BufferContent { .. } => {
5230                let excerpt_start = cursor.start().1 + start_overshoot;
5231                let excerpt_end = cursor.start().1 + end_overshoot;
5232                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5233            }
5234            DiffTransform::DeletedHunk {
5235                buffer_id,
5236                base_text_byte_range,
5237                has_trailing_newline,
5238                ..
5239            } => {
5240                let buffer_start = base_text_byte_range.start + start_overshoot;
5241                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5242                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5243                    panic!("{:?} is in non-existent deleted hunk", range.start)
5244                };
5245
5246                let include_trailing_newline =
5247                    *has_trailing_newline && range.end >= diff_transform_end;
5248                if include_trailing_newline {
5249                    buffer_end -= 1;
5250                }
5251
5252                let mut summary = base_text
5253                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5254
5255                if include_trailing_newline {
5256                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5257                        &TextSummary::newline(),
5258                    ))
5259                }
5260
5261                let mut result = MBD::default();
5262                result.add_text_dim(&summary);
5263                result
5264            }
5265        };
5266        if range.end < diff_transform_end {
5267            return result;
5268        }
5269
5270        cursor.next();
5271        result.add_mb_text_summary(
5272            &cursor
5273                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5274                .0,
5275        );
5276
5277        let Some(last_transform) = cursor.item() else {
5278            return result;
5279        };
5280
5281        let overshoot = range.end - cursor.start().0;
5282        let suffix = match last_transform {
5283            DiffTransform::BufferContent { .. } => {
5284                let end = cursor.start().1 + overshoot;
5285                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5286            }
5287            DiffTransform::DeletedHunk {
5288                base_text_byte_range,
5289                buffer_id,
5290                has_trailing_newline,
5291                ..
5292            } => {
5293                let buffer_end = base_text_byte_range.start + overshoot;
5294                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5295                    panic!("{:?} is in non-existent deleted hunk", range.end)
5296                };
5297
5298                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5299                    base_text_byte_range.start..buffer_end,
5300                );
5301                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5302                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5303                        &TextSummary::from("\n"),
5304                    ))
5305                }
5306
5307                let mut result = MBD::default();
5308                result.add_text_dim(&suffix);
5309                result
5310            }
5311        };
5312
5313        result += suffix;
5314        result
5315    }
5316
5317    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5318    where
5319        MBD: MultiBufferDimension + AddAssign,
5320    {
5321        let mut summary = MBD::default();
5322        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5323        cursor.seek(&range.start, Bias::Right);
5324        if let Some(excerpt) = cursor.item() {
5325            let mut end_before_newline = cursor.end();
5326            if excerpt.has_trailing_newline {
5327                end_before_newline -= 1;
5328            }
5329
5330            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5331            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5332            let end_in_excerpt =
5333                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5334            summary.add_text_dim(
5335                &excerpt
5336                    .buffer
5337                    .text_summary_for_range::<MBD::TextDimension, _>(
5338                        start_in_excerpt..end_in_excerpt,
5339                    ),
5340            );
5341
5342            if range.end > end_before_newline {
5343                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5344            }
5345
5346            cursor.next();
5347        }
5348
5349        if range.end > *cursor.start() {
5350            summary += cursor
5351                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5352                .0;
5353            if let Some(excerpt) = cursor.item() {
5354                range.end = cmp::max(*cursor.start(), range.end);
5355
5356                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5357                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5358                summary.add_text_dim(
5359                    &excerpt
5360                        .buffer
5361                        .text_summary_for_range::<MBD::TextDimension, _>(
5362                            excerpt_start..end_in_excerpt,
5363                        ),
5364                );
5365            }
5366        }
5367
5368        summary
5369    }
5370
5371    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5372    where
5373        MBD: MultiBufferDimension
5374            + Ord
5375            + Sub<Output = MBD::TextDimension>
5376            + Sub<MBD::TextDimension, Output = MBD>
5377            + AddAssign<MBD::TextDimension>
5378            + Add<MBD::TextDimension, Output = MBD>,
5379        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5380    {
5381        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5382        let locator = self.excerpt_locator_for_id(excerpt_id);
5383        let (start, _, mut item) = self
5384            .excerpts
5385            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5386        let mut start = MBD::from_summary(&start.text);
5387        if item.is_none() && excerpt_id == ExcerptId::max() {
5388            item = self.excerpts.last();
5389            if let Some(last_summary) = self.excerpts.last_summary() {
5390                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5391            }
5392        }
5393
5394        let excerpt_start_position = ExcerptDimension(start);
5395        if self.diff_transforms.is_empty() {
5396            if let Some(excerpt) = item {
5397                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5398                    return excerpt_start_position.0;
5399                }
5400                let excerpt_buffer_start = excerpt
5401                    .range
5402                    .context
5403                    .start
5404                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5405                let excerpt_buffer_end = excerpt
5406                    .range
5407                    .context
5408                    .end
5409                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5410                let buffer_summary = anchor
5411                    .text_anchor
5412                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5413                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5414                let mut position = excerpt_start_position;
5415                if summary > excerpt_buffer_start {
5416                    position += summary - excerpt_buffer_start;
5417                }
5418
5419                position.0
5420            } else {
5421                excerpt_start_position.0
5422            }
5423        } else {
5424            let mut diff_transforms_cursor = self
5425                .diff_transforms
5426                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5427            diff_transforms_cursor.next();
5428
5429            if let Some(excerpt) = item {
5430                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5431                    return self.resolve_summary_for_min_or_max_anchor(
5432                        &Anchor::min(),
5433                        excerpt_start_position,
5434                        &mut diff_transforms_cursor,
5435                    );
5436                }
5437                let excerpt_buffer_start = excerpt
5438                    .range
5439                    .context
5440                    .start
5441                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5442                let excerpt_buffer_end = excerpt
5443                    .range
5444                    .context
5445                    .end
5446                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5447                let buffer_summary = anchor
5448                    .text_anchor
5449                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5450                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5451                let mut position = excerpt_start_position;
5452                if summary > excerpt_buffer_start {
5453                    position += summary - excerpt_buffer_start;
5454                }
5455
5456                if diff_transforms_cursor.start().0 < position {
5457                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5458                }
5459                self.resolve_summary_for_anchor(
5460                    &anchor,
5461                    position,
5462                    &mut diff_transforms_cursor,
5463                    &excerpt.buffer,
5464                )
5465            } else {
5466                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5467                self.resolve_summary_for_min_or_max_anchor(
5468                    &Anchor::max(),
5469                    excerpt_start_position,
5470                    &mut diff_transforms_cursor,
5471                )
5472            }
5473        }
5474    }
5475
5476    /// Maps an anchor's excerpt-space position to its output-space position by
5477    /// walking the diff transforms. The cursor is shared across consecutive
5478    /// calls, so it may already be partway through the transform list.
5479    fn resolve_summary_for_anchor<MBD>(
5480        &self,
5481        anchor: &Anchor,
5482        excerpt_position: ExcerptDimension<MBD>,
5483        diff_transforms: &mut Cursor<
5484            DiffTransform,
5485            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5486        >,
5487        excerpt_buffer: &text::BufferSnapshot,
5488    ) -> MBD
5489    where
5490        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5491    {
5492        loop {
5493            let transform_end_position = diff_transforms.end().0;
5494            let item = diff_transforms.item();
5495            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5496
5497            // A right-biased anchor at a transform boundary belongs to the
5498            // *next* transform, so advance past the current one.
5499            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5500                diff_transforms.next();
5501                continue;
5502            }
5503
5504            let mut position = diff_transforms.start().1;
5505            match item {
5506                Some(DiffTransform::DeletedHunk {
5507                    buffer_id,
5508                    base_text_byte_range,
5509                    hunk_info,
5510                    ..
5511                }) => {
5512                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5513                        && let Some(base_text) =
5514                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5515                        && diff_base_anchor.is_valid(&base_text)
5516                    {
5517                        // The anchor carries a diff-base position — resolve it
5518                        // to a location inside the deleted hunk.
5519                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5520                        if base_text_offset >= base_text_byte_range.start
5521                            && base_text_offset <= base_text_byte_range.end
5522                        {
5523                            let position_in_hunk = base_text
5524                                .text_summary_for_range::<MBD::TextDimension, _>(
5525                                    base_text_byte_range.start..base_text_offset,
5526                                );
5527                            position.0.add_text_dim(&position_in_hunk);
5528                        } else if at_transform_end {
5529                            // diff_base offset falls outside this hunk's range;
5530                            // advance to see if the next transform is a better fit.
5531                            diff_transforms.next();
5532                            continue;
5533                        }
5534                    } else if at_transform_end
5535                        && anchor
5536                            .text_anchor
5537                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5538                            .is_gt()
5539                    {
5540                        // The anchor has no (valid) diff-base position, so it
5541                        // belongs in the buffer content, not in the deleted
5542                        // hunk. However, after an edit deletes the text between
5543                        // the hunk boundary and this anchor, both resolve to
5544                        // the same excerpt_position—landing us here on the
5545                        // DeletedHunk left behind by the shared cursor. Use the
5546                        // CRDT ordering to detect that the anchor is strictly
5547                        // *past* the hunk boundary and skip to the following
5548                        // BufferContent.
5549                        diff_transforms.next();
5550                        continue;
5551                    }
5552                }
5553                _ => {
5554                    // On a BufferContent (or no transform). If the anchor
5555                    // carries a diff_base_anchor it needs a DeletedHunk, so
5556                    // advance to find one.
5557                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5558                        diff_transforms.next();
5559                        continue;
5560                    }
5561                    let overshoot = excerpt_position - diff_transforms.start().0;
5562                    position += overshoot;
5563                }
5564            }
5565
5566            return position.0;
5567        }
5568    }
5569
5570    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5571    fn resolve_summary_for_min_or_max_anchor<MBD>(
5572        &self,
5573        anchor: &Anchor,
5574        excerpt_position: ExcerptDimension<MBD>,
5575        diff_transforms: &mut Cursor<
5576            DiffTransform,
5577            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5578        >,
5579    ) -> MBD
5580    where
5581        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5582    {
5583        loop {
5584            let transform_end_position = diff_transforms.end().0;
5585            let item = diff_transforms.item();
5586            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5587
5588            // A right-biased anchor at a transform boundary belongs to the
5589            // *next* transform, so advance past the current one.
5590            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5591                diff_transforms.next();
5592                continue;
5593            }
5594
5595            let mut position = diff_transforms.start().1;
5596            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5597                let overshoot = excerpt_position - diff_transforms.start().0;
5598                position += overshoot;
5599            }
5600
5601            return position.0;
5602        }
5603    }
5604
5605    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5606        let mut cursor = self
5607            .excerpts
5608            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5609        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5610
5611        cursor.seek(&Some(locator), Bias::Left);
5612        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5613            cursor.prev();
5614        }
5615
5616        let mut position = cursor.start().1;
5617        if let Some(excerpt) = cursor.item()
5618            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5619        {
5620            let excerpt_buffer_start = excerpt
5621                .buffer
5622                .offset_for_anchor(&excerpt.range.context.start);
5623            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5624            let buffer_position = cmp::min(
5625                excerpt_buffer_end,
5626                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5627            );
5628            if buffer_position > excerpt_buffer_start {
5629                position += buffer_position - excerpt_buffer_start;
5630            }
5631        }
5632        position
5633    }
5634
5635    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5636        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5637            excerpt_id = *replacement;
5638        }
5639        excerpt_id
5640    }
5641
5642    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5643    where
5644        MBD: MultiBufferDimension
5645            + Ord
5646            + Sub<Output = MBD::TextDimension>
5647            + AddAssign<MBD::TextDimension>,
5648        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5649        I: 'a + IntoIterator<Item = &'a Anchor>,
5650    {
5651        let mut anchors = anchors.into_iter().peekable();
5652        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5653        let mut diff_transforms_cursor = self
5654            .diff_transforms
5655            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5656        diff_transforms_cursor.next();
5657
5658        let mut summaries = Vec::new();
5659        while let Some(anchor) = anchors.peek() {
5660            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5661
5662            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5663                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5664            });
5665
5666            let locator = self.excerpt_locator_for_id(excerpt_id);
5667            cursor.seek_forward(locator, Bias::Left);
5668            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5669                cursor.prev();
5670            }
5671
5672            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5673            if let Some(excerpt) = cursor.item() {
5674                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5675                    let position = self.resolve_summary_for_min_or_max_anchor(
5676                        &Anchor::min(),
5677                        excerpt_start_position,
5678                        &mut diff_transforms_cursor,
5679                    );
5680                    summaries.extend(excerpt_anchors.map(|_| position));
5681                    continue;
5682                }
5683                let excerpt_buffer_start = excerpt
5684                    .range
5685                    .context
5686                    .start
5687                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5688                let excerpt_buffer_end = excerpt
5689                    .range
5690                    .context
5691                    .end
5692                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5693                for (buffer_summary, anchor) in excerpt
5694                    .buffer
5695                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5696                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5697                    )
5698                {
5699                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5700                    let mut position = excerpt_start_position;
5701                    if summary > excerpt_buffer_start {
5702                        position += summary - excerpt_buffer_start;
5703                    }
5704
5705                    if diff_transforms_cursor.start().0 < position {
5706                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5707                    }
5708
5709                    summaries.push(self.resolve_summary_for_anchor(
5710                        anchor,
5711                        position,
5712                        &mut diff_transforms_cursor,
5713                        &excerpt.buffer,
5714                    ));
5715                }
5716            } else {
5717                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5718                let position = self.resolve_summary_for_min_or_max_anchor(
5719                    &Anchor::max(),
5720                    excerpt_start_position,
5721                    &mut diff_transforms_cursor,
5722                );
5723                summaries.extend(excerpt_anchors.map(|_| position));
5724            }
5725        }
5726
5727        summaries
5728    }
5729
5730    pub fn dimensions_from_points<'a, MBD>(
5731        &'a self,
5732        points: impl 'a + IntoIterator<Item = Point>,
5733    ) -> impl 'a + Iterator<Item = MBD>
5734    where
5735        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5736    {
5737        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5738        cursor.seek(&DimensionPair {
5739            key: Point::default(),
5740            value: None,
5741        });
5742        let mut points = points.into_iter();
5743        iter::from_fn(move || {
5744            let point = points.next()?;
5745
5746            cursor.seek_forward(&DimensionPair {
5747                key: point,
5748                value: None,
5749            });
5750
5751            if let Some(region) = cursor.region() {
5752                let overshoot = point - region.range.start.key;
5753                let buffer_point = region.buffer_range.start + overshoot;
5754                let mut position = region.range.start.value.unwrap();
5755                position.add_text_dim(
5756                    &region
5757                        .buffer
5758                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5759                );
5760                if point == region.range.end.key && region.has_trailing_newline {
5761                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5762                }
5763                Some(position)
5764            } else {
5765                Some(MBD::from_summary(&self.text_summary()))
5766            }
5767        })
5768    }
5769
5770    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5771    where
5772        I: 'a + IntoIterator<Item = &'a Anchor>,
5773    {
5774        let mut anchors = anchors.into_iter().enumerate().peekable();
5775        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5776        cursor.next();
5777
5778        let mut result = Vec::new();
5779
5780        while let Some((_, anchor)) = anchors.peek() {
5781            let old_excerpt_id = anchor.excerpt_id;
5782
5783            // Find the location where this anchor's excerpt should be.
5784            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5785            cursor.seek_forward(&Some(old_locator), Bias::Left);
5786
5787            let next_excerpt = cursor.item();
5788            let prev_excerpt = cursor.prev_item();
5789
5790            // Process all of the anchors for this excerpt.
5791            while let Some((anchor_ix, &anchor)) =
5792                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5793            {
5794                let mut anchor = anchor;
5795
5796                // Leave min and max anchors unchanged if invalid or
5797                // if the old excerpt still exists at this location
5798                let mut kept_position = next_excerpt
5799                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5800                    || old_excerpt_id == ExcerptId::max()
5801                    || old_excerpt_id == ExcerptId::min();
5802
5803                // If the old excerpt no longer exists at this location, then attempt to
5804                // find an equivalent position for this anchor in an adjacent excerpt.
5805                if !kept_position {
5806                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5807                        if excerpt.contains(&anchor) {
5808                            anchor.excerpt_id = excerpt.id;
5809                            kept_position = true;
5810                            break;
5811                        }
5812                    }
5813                }
5814
5815                // If there's no adjacent excerpt that contains the anchor's position,
5816                // then report that the anchor has lost its position.
5817                if !kept_position {
5818                    anchor = if let Some(excerpt) = next_excerpt {
5819                        let mut text_anchor = excerpt
5820                            .range
5821                            .context
5822                            .start
5823                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5824                        if text_anchor
5825                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5826                            .is_gt()
5827                        {
5828                            text_anchor = excerpt.range.context.end;
5829                        }
5830                        Anchor::in_buffer(excerpt.id, text_anchor)
5831                    } else if let Some(excerpt) = prev_excerpt {
5832                        let mut text_anchor = excerpt
5833                            .range
5834                            .context
5835                            .end
5836                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5837                        if text_anchor
5838                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5839                            .is_lt()
5840                        {
5841                            text_anchor = excerpt.range.context.start;
5842                        }
5843                        Anchor::in_buffer(excerpt.id, text_anchor)
5844                    } else if anchor.text_anchor.bias == Bias::Left {
5845                        Anchor::min()
5846                    } else {
5847                        Anchor::max()
5848                    };
5849                }
5850
5851                result.push((anchor_ix, anchor, kept_position));
5852            }
5853        }
5854        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5855        result
5856    }
5857
5858    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5859        self.anchor_at(position, Bias::Left)
5860    }
5861
5862    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5863        self.anchor_at(position, Bias::Right)
5864    }
5865
5866    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5867        let offset = position.to_offset(self);
5868
5869        // Find the given position in the diff transforms. Determine the corresponding
5870        // offset in the excerpts, and whether the position is within a deleted hunk.
5871        let mut diff_transforms = self
5872            .diff_transforms
5873            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5874        diff_transforms.seek(&offset, Bias::Right);
5875
5876        if offset == diff_transforms.start().0
5877            && bias == Bias::Left
5878            && let Some(prev_item) = diff_transforms.prev_item()
5879            && let DiffTransform::DeletedHunk { .. } = prev_item
5880        {
5881            diff_transforms.prev();
5882        }
5883        let offset_in_transform = offset - diff_transforms.start().0;
5884        let mut excerpt_offset = diff_transforms.start().1;
5885        let mut diff_base_anchor = None;
5886        if let Some(DiffTransform::DeletedHunk {
5887            buffer_id,
5888            base_text_byte_range,
5889            has_trailing_newline,
5890            ..
5891        }) = diff_transforms.item()
5892        {
5893            let diff = self.diffs.get(buffer_id).expect("missing diff");
5894            if offset_in_transform > base_text_byte_range.len() {
5895                debug_assert!(*has_trailing_newline);
5896                bias = Bias::Right;
5897            } else {
5898                diff_base_anchor = Some(
5899                    diff.base_text()
5900                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5901                );
5902                bias = Bias::Left;
5903            }
5904        } else {
5905            excerpt_offset += MultiBufferOffset(offset_in_transform);
5906        };
5907
5908        let mut excerpts = self
5909            .excerpts
5910            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5911        excerpts.seek(&excerpt_offset, Bias::Right);
5912        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5913            excerpts.prev();
5914        }
5915        if let Some(excerpt) = excerpts.item() {
5916            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5917            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5918                overshoot -= 1;
5919                bias = Bias::Right;
5920            }
5921
5922            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5923            let text_anchor =
5924                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5925            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5926            match diff_base_anchor {
5927                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5928                None => anchor,
5929            }
5930        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5931        {
5932            Anchor::min()
5933        } else {
5934            Anchor::max()
5935        }
5936    }
5937
5938    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5939    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5940        let (excerpt, buffer, _) = self.as_singleton()?;
5941        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5942            Some(Anchor::in_buffer(excerpt, text_anchor))
5943        } else {
5944            None
5945        }
5946    }
5947
5948    /// Returns an anchor for the given excerpt and text anchor,
5949    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5950    pub fn anchor_range_in_excerpt(
5951        &self,
5952        excerpt_id: ExcerptId,
5953        text_anchor: Range<text::Anchor>,
5954    ) -> Option<Range<Anchor>> {
5955        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5956
5957        Some(
5958            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5959                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
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_in_excerpt(
5966        &self,
5967        excerpt_id: ExcerptId,
5968        text_anchor: text::Anchor,
5969    ) -> Option<Anchor> {
5970        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5971        Self::anchor_in_excerpt_(excerpt, text_anchor)
5972    }
5973
5974    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5975    pub fn anchors_in_excerpt(
5976        &self,
5977        excerpt_id: ExcerptId,
5978        text_anchors: impl IntoIterator<Item = text::Anchor>,
5979    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5980        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5981        Some(
5982            text_anchors
5983                .into_iter()
5984                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5985        )
5986    }
5987
5988    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5989        match text_anchor.buffer_id {
5990            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5991            Some(_) => return None,
5992            None if text_anchor.is_max() || text_anchor.is_min() => {
5993                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5994            }
5995            None => return None,
5996        }
5997
5998        let context = &excerpt.range.context;
5999        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6000            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6001        {
6002            return None;
6003        }
6004
6005        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6006    }
6007
6008    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6009        Some(self.excerpt(excerpt_id)?.range.context.clone())
6010    }
6011
6012    pub fn excerpt_range_for_excerpt(
6013        &self,
6014        excerpt_id: ExcerptId,
6015    ) -> Option<ExcerptRange<text::Anchor>> {
6016        Some(self.excerpt(excerpt_id)?.range.clone())
6017    }
6018
6019    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6020        if anchor.is_min() || anchor.is_max() {
6021            // todo(lw): should be `!self.is_empty()`
6022            true
6023        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6024            excerpt.buffer.can_resolve(&anchor.text_anchor)
6025        } else {
6026            false
6027        }
6028    }
6029
6030    pub fn excerpts(
6031        &self,
6032    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6033        self.excerpts
6034            .iter()
6035            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6036    }
6037
6038    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6039    where
6040        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6041        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6042    {
6043        let excerpts = self.excerpts.cursor(());
6044        let diff_transforms = self.diff_transforms.cursor(());
6045        MultiBufferCursor {
6046            excerpts,
6047            diff_transforms,
6048            diffs: &self.diffs,
6049            cached_region: OnceCell::new(),
6050        }
6051    }
6052
6053    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6054        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6055        let mut excerpts = self
6056            .excerpts
6057            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6058        excerpts.seek(&Some(start_locator), Bias::Left);
6059        excerpts.prev();
6060
6061        let mut diff_transforms = self
6062            .diff_transforms
6063            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6064        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6065        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6066            diff_transforms.next();
6067        }
6068
6069        let excerpt = excerpts.item()?;
6070        Some(MultiBufferExcerpt {
6071            excerpt,
6072            offset: diff_transforms.start().output_dimension.0,
6073            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6074            excerpt_offset: excerpts.start().1,
6075            diff_transforms,
6076        })
6077    }
6078
6079    pub fn excerpt_boundaries_in_range<R, T>(
6080        &self,
6081        range: R,
6082    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6083    where
6084        R: RangeBounds<T>,
6085        T: ToOffset,
6086    {
6087        let start_offset;
6088        let start = match range.start_bound() {
6089            Bound::Included(start) => {
6090                start_offset = start.to_offset(self);
6091                Bound::Included(start_offset)
6092            }
6093            Bound::Excluded(_) => {
6094                panic!("not supported")
6095            }
6096            Bound::Unbounded => {
6097                start_offset = MultiBufferOffset::ZERO;
6098                Bound::Unbounded
6099            }
6100        };
6101        let end = match range.end_bound() {
6102            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6103            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6104            Bound::Unbounded => Bound::Unbounded,
6105        };
6106        let bounds = (start, end);
6107        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6108        cursor.seek(&DimensionPair {
6109            key: start_offset,
6110            value: None,
6111        });
6112
6113        if cursor
6114            .fetch_excerpt_with_range()
6115            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6116        {
6117            cursor.prev_excerpt();
6118        } else {
6119            cursor.seek_to_start_of_current_excerpt();
6120        }
6121        let mut prev_region = cursor
6122            .fetch_excerpt_with_range()
6123            .map(|(excerpt, _)| excerpt);
6124
6125        cursor.next_excerpt_forwards();
6126
6127        iter::from_fn(move || {
6128            loop {
6129                if self.singleton {
6130                    return None;
6131                }
6132
6133                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6134                cursor.next_excerpt_forwards();
6135                if !bounds.contains(&next_range.start.key) {
6136                    prev_region = Some(next_excerpt);
6137                    continue;
6138                }
6139
6140                let next_region_start = next_range.start.value.unwrap();
6141                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6142                    range.start.value.unwrap()
6143                } else {
6144                    self.max_point()
6145                };
6146
6147                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6148                    id: region.id,
6149                    buffer: region.buffer.clone(),
6150                    buffer_id: region.buffer_id,
6151                    range: region.range.clone(),
6152                    end_row: MultiBufferRow(next_region_start.row),
6153                });
6154
6155                let next = ExcerptInfo {
6156                    id: next_excerpt.id,
6157                    buffer: next_excerpt.buffer.clone(),
6158                    buffer_id: next_excerpt.buffer_id,
6159                    range: next_excerpt.range.clone(),
6160                    end_row: if next_excerpt.has_trailing_newline {
6161                        MultiBufferRow(next_region_end.row - 1)
6162                    } else {
6163                        MultiBufferRow(next_region_end.row)
6164                    },
6165                };
6166
6167                let row = MultiBufferRow(next_region_start.row);
6168
6169                prev_region = Some(next_excerpt);
6170
6171                return Some(ExcerptBoundary { row, prev, next });
6172            }
6173        })
6174    }
6175
6176    pub fn edit_count(&self) -> usize {
6177        self.edit_count
6178    }
6179
6180    pub fn non_text_state_update_count(&self) -> usize {
6181        self.non_text_state_update_count
6182    }
6183
6184    /// Returns the smallest enclosing bracket ranges containing the given range or
6185    /// None if no brackets contain range or the range is not contained in a single
6186    /// excerpt
6187    ///
6188    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6189    #[ztracing::instrument(skip_all)]
6190    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6191        &self,
6192        range: Range<T>,
6193        range_filter: Option<
6194            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6195        >,
6196    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6197        let range = range.start.to_offset(self)..range.end.to_offset(self);
6198        let mut excerpt = self.excerpt_containing(range.clone())?;
6199        let buffer = excerpt.buffer();
6200        let excerpt_buffer_range = excerpt.buffer_range();
6201
6202        // Filter to ranges contained in the excerpt
6203        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6204            excerpt_buffer_range.contains(&BufferOffset(open.start))
6205                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6206                && range_filter.is_none_or(|filter| {
6207                    filter(
6208                        buffer,
6209                        BufferOffset(open.start)..BufferOffset(close.end),
6210                        BufferOffset(close.start)..BufferOffset(close.end),
6211                    )
6212                })
6213        };
6214
6215        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6216            excerpt.map_range_to_buffer(range),
6217            Some(&range_filter),
6218        )?;
6219
6220        Some((
6221            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6222            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6223        ))
6224    }
6225
6226    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6227    /// not contained in a single excerpt
6228    pub fn enclosing_bracket_ranges<T: ToOffset>(
6229        &self,
6230        range: Range<T>,
6231    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6232    {
6233        let range = range.start.to_offset(self)..range.end.to_offset(self);
6234        let mut excerpt = self.excerpt_containing(range.clone())?;
6235
6236        Some(
6237            excerpt
6238                .buffer()
6239                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6240                .filter_map(move |pair| {
6241                    let open_range =
6242                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6243                    let close_range =
6244                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6245                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6246                        Some((
6247                            excerpt.map_range_from_buffer(open_range),
6248                            excerpt.map_range_from_buffer(close_range),
6249                        ))
6250                    } else {
6251                        None
6252                    }
6253                }),
6254        )
6255    }
6256
6257    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6258    /// not contained in a single excerpt
6259    pub fn text_object_ranges<T: ToOffset>(
6260        &self,
6261        range: Range<T>,
6262        options: TreeSitterOptions,
6263    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6264        let range = range.start.to_offset(self)..range.end.to_offset(self);
6265        self.excerpt_containing(range.clone())
6266            .map(|mut excerpt| {
6267                excerpt
6268                    .buffer()
6269                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6270                    .filter_map(move |(range, text_object)| {
6271                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6272                        if excerpt.contains_buffer_range(range.clone()) {
6273                            Some((excerpt.map_range_from_buffer(range), text_object))
6274                        } else {
6275                            None
6276                        }
6277                    })
6278            })
6279            .into_iter()
6280            .flatten()
6281    }
6282
6283    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6284    /// not contained in a single excerpt
6285    pub fn bracket_ranges<T: ToOffset>(
6286        &self,
6287        range: Range<T>,
6288    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6289    {
6290        let range = range.start.to_offset(self)..range.end.to_offset(self);
6291        let mut excerpt = self.excerpt_containing(range.clone())?;
6292        Some(
6293            excerpt
6294                .buffer()
6295                .bracket_ranges(excerpt.map_range_to_buffer(range))
6296                .filter_map(move |pair| {
6297                    let open_range =
6298                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6299                    let close_range =
6300                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6301                    excerpt
6302                        .contains_buffer_range(open_range.start..close_range.end)
6303                        .then(|| BracketMatch {
6304                            open_range: excerpt.map_range_from_buffer(open_range),
6305                            close_range: excerpt.map_range_from_buffer(close_range),
6306                            color_index: pair.color_index,
6307                            newline_only: pair.newline_only,
6308                            syntax_layer_depth: pair.syntax_layer_depth,
6309                        })
6310                })
6311                .map(BracketMatch::bracket_ranges),
6312        )
6313    }
6314
6315    pub fn redacted_ranges<'a, T: ToOffset>(
6316        &'a self,
6317        range: Range<T>,
6318        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6319    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6320        let range = range.start.to_offset(self)..range.end.to_offset(self);
6321        self.lift_buffer_metadata(range, move |buffer, range| {
6322            if redaction_enabled(buffer.file()) {
6323                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6324            } else {
6325                None
6326            }
6327        })
6328        .map(|(range, _, _)| range)
6329    }
6330
6331    pub fn runnable_ranges(
6332        &self,
6333        range: Range<Anchor>,
6334    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6335        let range = range.start.to_offset(self)..range.end.to_offset(self);
6336        self.lift_buffer_metadata(range, move |buffer, range| {
6337            Some(
6338                buffer
6339                    .runnable_ranges(range.clone())
6340                    .filter(move |runnable| {
6341                        runnable.run_range.start >= range.start
6342                            && runnable.run_range.end < range.end
6343                    })
6344                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6345            )
6346        })
6347        .map(|(run_range, runnable, _)| (run_range, runnable))
6348    }
6349
6350    pub fn line_indents(
6351        &self,
6352        start_row: MultiBufferRow,
6353        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6354    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6355        let max_point = self.max_point();
6356        let mut cursor = self.cursor::<Point, Point>();
6357        cursor.seek(&Point::new(start_row.0, 0));
6358        iter::from_fn(move || {
6359            let mut region = cursor.region()?;
6360            while !buffer_filter(&region.excerpt.buffer) {
6361                cursor.next();
6362                region = cursor.region()?;
6363            }
6364            let region = cursor.region()?;
6365            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6366            let buffer_start_row =
6367                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6368
6369            let buffer_end_row = if region.is_main_buffer
6370                && (region.has_trailing_newline || region.range.end == max_point)
6371            {
6372                region.buffer_range.end.row
6373            } else {
6374                region.buffer_range.end.row.saturating_sub(1)
6375            };
6376
6377            let line_indents = region
6378                .buffer
6379                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6380            let region_buffer_row = region.buffer_range.start.row;
6381            let region_row = region.range.start.row;
6382            let region_buffer = &region.excerpt.buffer;
6383            cursor.next();
6384            Some(line_indents.map(move |(buffer_row, indent)| {
6385                let row = region_row + (buffer_row - region_buffer_row);
6386                (MultiBufferRow(row), indent, region_buffer.as_ref())
6387            }))
6388        })
6389        .flatten()
6390    }
6391
6392    pub fn reversed_line_indents(
6393        &self,
6394        end_row: MultiBufferRow,
6395        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6396    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6397        let max_point = self.max_point();
6398        let mut cursor = self.cursor::<Point, Point>();
6399        cursor.seek(&Point::new(end_row.0, 0));
6400        iter::from_fn(move || {
6401            let mut region = cursor.region()?;
6402            while !buffer_filter(&region.excerpt.buffer) {
6403                cursor.prev();
6404                region = cursor.region()?;
6405            }
6406            let region = cursor.region()?;
6407
6408            let buffer_start_row = region.buffer_range.start.row;
6409            let buffer_end_row = if region.is_main_buffer
6410                && (region.has_trailing_newline || region.range.end == max_point)
6411            {
6412                region.buffer_range.end.row + 1
6413            } else {
6414                region.buffer_range.end.row
6415            };
6416
6417            let overshoot = end_row.0 - region.range.start.row;
6418            let buffer_end_row =
6419                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6420
6421            let line_indents = region
6422                .buffer
6423                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6424            let region_buffer_row = region.buffer_range.start.row;
6425            let region_row = region.range.start.row;
6426            let region_buffer = &region.excerpt.buffer;
6427            cursor.prev();
6428            Some(line_indents.map(move |(buffer_row, indent)| {
6429                let row = region_row + (buffer_row - region_buffer_row);
6430                (MultiBufferRow(row), indent, region_buffer.as_ref())
6431            }))
6432        })
6433        .flatten()
6434    }
6435
6436    pub async fn enclosing_indent(
6437        &self,
6438        mut target_row: MultiBufferRow,
6439    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6440        let max_row = MultiBufferRow(self.max_point().row);
6441        if target_row >= max_row {
6442            return None;
6443        }
6444
6445        let mut target_indent = self.line_indent_for_row(target_row);
6446
6447        // If the current row is at the start of an indented block, we want to return this
6448        // block as the enclosing indent.
6449        if !target_indent.is_line_empty() && target_row < max_row {
6450            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6451            if !next_line_indent.is_line_empty()
6452                && target_indent.raw_len() < next_line_indent.raw_len()
6453            {
6454                target_indent = next_line_indent;
6455                target_row.0 += 1;
6456            }
6457        }
6458
6459        const SEARCH_ROW_LIMIT: u32 = 25000;
6460        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6461        const YIELD_INTERVAL: u32 = 100;
6462
6463        let mut accessed_row_counter = 0;
6464
6465        // If there is a blank line at the current row, search for the next non indented lines
6466        if target_indent.is_line_empty() {
6467            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6468            let end =
6469                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6470
6471            let mut non_empty_line_above = None;
6472            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6473                if row < start {
6474                    break;
6475                }
6476                accessed_row_counter += 1;
6477                if accessed_row_counter == YIELD_INTERVAL {
6478                    accessed_row_counter = 0;
6479                    yield_now().await;
6480                }
6481                if !indent.is_line_empty() {
6482                    non_empty_line_above = Some((row, indent));
6483                    break;
6484                }
6485            }
6486
6487            let mut non_empty_line_below = None;
6488            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6489                if row > end {
6490                    break;
6491                }
6492                accessed_row_counter += 1;
6493                if accessed_row_counter == YIELD_INTERVAL {
6494                    accessed_row_counter = 0;
6495                    yield_now().await;
6496                }
6497                if !indent.is_line_empty() {
6498                    non_empty_line_below = Some((row, indent));
6499                    break;
6500                }
6501            }
6502
6503            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6504                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6505                    if above_indent.raw_len() >= below_indent.raw_len() {
6506                        (above_row, above_indent)
6507                    } else {
6508                        (below_row, below_indent)
6509                    }
6510                }
6511                (Some(above), None) => above,
6512                (None, Some(below)) => below,
6513                _ => return None,
6514            };
6515
6516            target_indent = indent;
6517            target_row = row;
6518        }
6519
6520        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6521        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6522
6523        let mut start_indent = None;
6524        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6525            if row < start {
6526                break;
6527            }
6528            accessed_row_counter += 1;
6529            if accessed_row_counter == YIELD_INTERVAL {
6530                accessed_row_counter = 0;
6531                yield_now().await;
6532            }
6533            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6534                start_indent = Some((row, indent));
6535                break;
6536            }
6537        }
6538        let (start_row, start_indent_size) = start_indent?;
6539
6540        let mut end_indent = (end, None);
6541        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6542            if row > end {
6543                break;
6544            }
6545            accessed_row_counter += 1;
6546            if accessed_row_counter == YIELD_INTERVAL {
6547                accessed_row_counter = 0;
6548                yield_now().await;
6549            }
6550            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6551                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6552                break;
6553            }
6554        }
6555        let (end_row, end_indent_size) = end_indent;
6556
6557        let indent = if let Some(end_indent_size) = end_indent_size {
6558            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6559                start_indent_size
6560            } else {
6561                end_indent_size
6562            }
6563        } else {
6564            start_indent_size
6565        };
6566
6567        Some((start_row..end_row, indent))
6568    }
6569
6570    pub fn indent_guides_in_range<T: ToPoint>(
6571        &self,
6572        range: Range<T>,
6573        ignore_disabled_for_language: bool,
6574        cx: &App,
6575    ) -> impl Iterator<Item = IndentGuide> {
6576        let range = range.start.to_point(self)..range.end.to_point(self);
6577        let start_row = MultiBufferRow(range.start.row);
6578        let end_row = MultiBufferRow(range.end.row);
6579
6580        let mut row_indents = self.line_indents(start_row, |buffer| {
6581            let settings =
6582                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6583            settings.indent_guides.enabled || ignore_disabled_for_language
6584        });
6585
6586        let mut result = Vec::new();
6587        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6588
6589        let mut prev_settings = None;
6590        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6591            if first_row > end_row {
6592                break;
6593            }
6594            let current_depth = indent_stack.len() as u32;
6595
6596            // Avoid retrieving the language settings repeatedly for every buffer row.
6597            if let Some((prev_buffer_id, _)) = &prev_settings
6598                && prev_buffer_id != &buffer.remote_id()
6599            {
6600                prev_settings.take();
6601            }
6602            let settings = &prev_settings
6603                .get_or_insert_with(|| {
6604                    (
6605                        buffer.remote_id(),
6606                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6607                    )
6608                })
6609                .1;
6610            let tab_size = settings.tab_size.get();
6611
6612            // When encountering empty, continue until found useful line indent
6613            // then add to the indent stack with the depth found
6614            let mut found_indent = false;
6615            let mut last_row = first_row;
6616            if line_indent.is_line_blank() {
6617                while !found_indent {
6618                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6619                        break;
6620                    };
6621                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6622                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6623                        break;
6624                    }
6625
6626                    if new_line_indent.is_line_blank() {
6627                        continue;
6628                    }
6629                    last_row = target_row.min(end_row);
6630                    line_indent = new_line_indent;
6631                    found_indent = true;
6632                    break;
6633                }
6634            } else {
6635                found_indent = true
6636            }
6637
6638            let depth = if found_indent {
6639                line_indent.len(tab_size) / tab_size
6640            } else {
6641                0
6642            };
6643
6644            match depth.cmp(&current_depth) {
6645                cmp::Ordering::Less => {
6646                    for _ in 0..(current_depth - depth) {
6647                        let mut indent = indent_stack.pop().unwrap();
6648                        if last_row != first_row {
6649                            // In this case, we landed on an empty row, had to seek forward,
6650                            // and discovered that the indent we where on is ending.
6651                            // This means that the last display row must
6652                            // be on line that ends this indent range, so we
6653                            // should display the range up to the first non-empty line
6654                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6655                        }
6656
6657                        result.push(indent)
6658                    }
6659                }
6660                cmp::Ordering::Greater => {
6661                    for next_depth in current_depth..depth {
6662                        indent_stack.push(IndentGuide {
6663                            buffer_id: buffer.remote_id(),
6664                            start_row: first_row,
6665                            end_row: last_row,
6666                            depth: next_depth,
6667                            tab_size,
6668                            settings: settings.indent_guides.clone(),
6669                        });
6670                    }
6671                }
6672                _ => {}
6673            }
6674
6675            for indent in indent_stack.iter_mut() {
6676                indent.end_row = last_row;
6677            }
6678        }
6679
6680        result.extend(indent_stack);
6681        result.into_iter()
6682    }
6683
6684    pub fn trailing_excerpt_update_count(&self) -> usize {
6685        self.trailing_excerpt_update_count
6686    }
6687
6688    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6689        self.point_to_buffer_offset(point)
6690            .and_then(|(buffer, _)| buffer.file())
6691    }
6692
6693    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6694        self.point_to_buffer_offset(offset)
6695            .and_then(|(buffer, offset)| buffer.language_at(offset))
6696    }
6697
6698    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6699        self.excerpts
6700            .first()
6701            .map(|excerpt| &excerpt.buffer)
6702            .map(|buffer| {
6703                language_settings(
6704                    buffer.language().map(|language| language.name()),
6705                    buffer.file(),
6706                    cx,
6707                )
6708            })
6709            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6710    }
6711
6712    pub fn language_settings_at<'a, T: ToOffset>(
6713        &'a self,
6714        point: T,
6715        cx: &'a App,
6716    ) -> Cow<'a, LanguageSettings> {
6717        let mut language = None;
6718        let mut file = None;
6719        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6720            language = buffer.language_at(offset);
6721            file = buffer.file();
6722        }
6723        language_settings(language.map(|l| l.name()), file, cx)
6724    }
6725
6726    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6727        self.point_to_buffer_offset(point)
6728            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6729    }
6730
6731    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6732        self.point_to_buffer_offset(point)
6733            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6734            .unwrap_or_default()
6735    }
6736
6737    pub fn language_indent_size_at<T: ToOffset>(
6738        &self,
6739        position: T,
6740        cx: &App,
6741    ) -> Option<IndentSize> {
6742        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6743        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6744    }
6745
6746    pub fn is_dirty(&self) -> bool {
6747        self.is_dirty
6748    }
6749
6750    pub fn has_deleted_file(&self) -> bool {
6751        self.has_deleted_file
6752    }
6753
6754    pub fn has_conflict(&self) -> bool {
6755        self.has_conflict
6756    }
6757
6758    pub fn has_diagnostics(&self) -> bool {
6759        self.excerpts
6760            .iter()
6761            .any(|excerpt| excerpt.buffer.has_diagnostics())
6762    }
6763
6764    pub fn diagnostic_group(
6765        &self,
6766        buffer_id: BufferId,
6767        group_id: usize,
6768    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6769        self.lift_buffer_metadata::<Point, _, _>(
6770            Point::zero()..self.max_point(),
6771            move |buffer, range| {
6772                if buffer.remote_id() != buffer_id {
6773                    return None;
6774                };
6775                Some(
6776                    buffer
6777                        .diagnostics_in_range(range, false)
6778                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6779                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6780                )
6781            },
6782        )
6783        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6784    }
6785
6786    pub fn diagnostics_in_range<'a, MBD>(
6787        &'a self,
6788        range: Range<MBD>,
6789    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6790    where
6791        MBD::TextDimension: 'a
6792            + text::ToOffset
6793            + text::FromAnchor
6794            + Sub<Output = MBD::TextDimension>
6795            + fmt::Debug
6796            + ops::Add<Output = MBD::TextDimension>
6797            + ops::AddAssign
6798            + Ord,
6799        MBD: MultiBufferDimension
6800            + Ord
6801            + Sub<Output = MBD::TextDimension>
6802            + ops::Add<MBD::TextDimension, Output = MBD>
6803            + ops::AddAssign<MBD::TextDimension>
6804            + 'a,
6805    {
6806        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6807            Some(
6808                buffer
6809                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6810                    .map(|entry| (entry.range, entry.diagnostic)),
6811            )
6812        })
6813        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6814    }
6815
6816    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6817        &'a self,
6818        range: Range<MBD>,
6819    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6820    where
6821        MBD: MultiBufferDimension
6822            + Ord
6823            + Sub<Output = MBD::TextDimension>
6824            + ops::Add<MBD::TextDimension, Output = MBD>
6825            + ops::AddAssign<MBD::TextDimension>,
6826        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6827            + ops::Add<Output = MBD::TextDimension>
6828            + text::ToOffset
6829            + text::FromAnchor
6830            + AddAssign<MBD::TextDimension>
6831            + Ord,
6832    {
6833        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6834            Some(
6835                buffer
6836                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6837                    .map(|entry| (entry.range, entry.diagnostic)),
6838            )
6839        })
6840        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6841    }
6842
6843    pub fn syntax_ancestor<T: ToOffset>(
6844        &self,
6845        range: Range<T>,
6846    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6847        let range = range.start.to_offset(self)..range.end.to_offset(self);
6848        let mut excerpt = self.excerpt_containing(range.clone())?;
6849        let node = excerpt
6850            .buffer()
6851            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6852        let node_range = node.byte_range();
6853        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6854        if !excerpt.contains_buffer_range(node_range.clone()) {
6855            return None;
6856        };
6857        Some((node, excerpt.map_range_from_buffer(node_range)))
6858    }
6859
6860    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6861        let (excerpt_id, _, buffer) = self.as_singleton()?;
6862        let outline = buffer.outline(theme);
6863        Some(Outline::new(
6864            outline
6865                .items
6866                .into_iter()
6867                .flat_map(|item| {
6868                    Some(OutlineItem {
6869                        depth: item.depth,
6870                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6871                        source_range_for_text: self
6872                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6873                        text: item.text,
6874                        highlight_ranges: item.highlight_ranges,
6875                        name_ranges: item.name_ranges,
6876                        body_range: item.body_range.and_then(|body_range| {
6877                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6878                        }),
6879                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6880                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6881                        }),
6882                    })
6883                })
6884                .collect(),
6885        ))
6886    }
6887
6888    pub fn symbols_containing<T: ToOffset>(
6889        &self,
6890        offset: T,
6891        theme: Option<&SyntaxTheme>,
6892    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6893        let anchor = self.anchor_before(offset);
6894        let excerpt @ &Excerpt {
6895            id: excerpt_id,
6896            buffer_id,
6897            ref buffer,
6898            ..
6899        } = self.excerpt(anchor.excerpt_id)?;
6900        if cfg!(debug_assertions) {
6901            match anchor.text_anchor.buffer_id {
6902                // we clearly are hitting this according to sentry, but in what situations can this occur?
6903                Some(anchor_buffer_id) => {
6904                    assert_eq!(
6905                        anchor_buffer_id, buffer_id,
6906                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6907                    )
6908                }
6909                None => assert!(anchor.is_max()),
6910            }
6911        };
6912        Some((
6913            buffer_id,
6914            buffer
6915                .symbols_containing(anchor.text_anchor, theme)
6916                .into_iter()
6917                .flat_map(|item| {
6918                    Some(OutlineItem {
6919                        depth: item.depth,
6920                        source_range_for_text: Anchor::range_in_buffer(
6921                            excerpt_id,
6922                            item.source_range_for_text,
6923                        ),
6924                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6925                        text: item.text,
6926                        highlight_ranges: item.highlight_ranges,
6927                        name_ranges: item.name_ranges,
6928                        body_range: item
6929                            .body_range
6930                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6931                        annotation_range: item
6932                            .annotation_range
6933                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6934                    })
6935                })
6936                .collect(),
6937        ))
6938    }
6939
6940    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6941        self.try_excerpt_locator_for_id(id)
6942            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6943    }
6944
6945    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6946        if id == ExcerptId::min() {
6947            Some(Locator::min_ref())
6948        } else if id == ExcerptId::max() {
6949            Some(Locator::max_ref())
6950        } else {
6951            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6952            if let Some(entry) = item
6953                && entry.id == id
6954            {
6955                return Some(&entry.locator);
6956            }
6957            None
6958        }
6959    }
6960
6961    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6962    fn excerpt_locators_for_ids(
6963        &self,
6964        ids: impl IntoIterator<Item = ExcerptId>,
6965    ) -> SmallVec<[Locator; 1]> {
6966        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6967        sorted_ids.sort_unstable();
6968        sorted_ids.dedup();
6969        let mut locators = SmallVec::new();
6970
6971        while sorted_ids.last() == Some(&ExcerptId::max()) {
6972            sorted_ids.pop();
6973            locators.push(Locator::max());
6974        }
6975
6976        let mut sorted_ids = sorted_ids.into_iter().peekable();
6977        locators.extend(
6978            sorted_ids
6979                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6980                .map(|_| Locator::min()),
6981        );
6982
6983        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6984        for id in sorted_ids {
6985            if cursor.seek_forward(&id, Bias::Left) {
6986                locators.push(cursor.item().unwrap().locator.clone());
6987            } else {
6988                panic!("invalid excerpt id {:?}", id);
6989            }
6990        }
6991
6992        locators.sort_unstable();
6993        locators
6994    }
6995
6996    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6997        Some(self.excerpt(excerpt_id)?.buffer_id)
6998    }
6999
7000    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7001        Some(&self.excerpt(excerpt_id)?.buffer)
7002    }
7003
7004    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7005        let mut cursor = self
7006            .excerpts
7007            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7008        let locator = self.excerpt_locator_for_id(excerpt_id);
7009        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7010        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7011            sought_exact = true;
7012            cursor.prev();
7013        } else if excerpt_id == ExcerptId::min() {
7014            sought_exact = true;
7015        }
7016        if sought_exact {
7017            let start = cursor.start().1;
7018            let end = cursor.end().1;
7019            let mut diff_transforms = self
7020                .diff_transforms
7021                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7022            diff_transforms.seek(&start, Bias::Left);
7023            let overshoot = start - diff_transforms.start().0;
7024            let start = diff_transforms.start().1 + overshoot;
7025            diff_transforms.seek(&end, Bias::Right);
7026            let overshoot = end - diff_transforms.start().0;
7027            let end = diff_transforms.start().1 + overshoot;
7028            Some(start.0..end.0)
7029        } else {
7030            None
7031        }
7032    }
7033
7034    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7035    /// to have the latest excerpt id for the one passed in and will also remap
7036    /// `ExcerptId::max()` to the corresponding excertp ID.
7037    ///
7038    /// Callers of this function should generally use the resulting excerpt's `id` field
7039    /// afterwards.
7040    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7041        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7042        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7043        let (_, _, item) =
7044            self.excerpts
7045                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7046        if let Some(excerpt) = item
7047            && excerpt.id == excerpt_id
7048        {
7049            return Some(excerpt);
7050        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7051            return self.excerpts.last();
7052        }
7053        None
7054    }
7055
7056    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7057    pub fn excerpt_containing<T: ToOffset>(
7058        &self,
7059        range: Range<T>,
7060    ) -> Option<MultiBufferExcerpt<'_>> {
7061        let range = range.start.to_offset(self)..range.end.to_offset(self);
7062        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7063        cursor.seek(&range.start);
7064
7065        let start_excerpt = cursor.excerpt()?;
7066        if range.end != range.start {
7067            cursor.seek_forward(&range.end);
7068            if cursor.excerpt()?.id != start_excerpt.id {
7069                return None;
7070            }
7071        }
7072
7073        cursor.seek_to_start_of_current_excerpt();
7074        let region = cursor.region()?;
7075        let offset = region.range.start;
7076        let buffer_offset = start_excerpt.buffer_start_offset();
7077        let excerpt_offset = *cursor.excerpts.start();
7078        Some(MultiBufferExcerpt {
7079            diff_transforms: cursor.diff_transforms,
7080            excerpt: start_excerpt,
7081            offset,
7082            buffer_offset,
7083            excerpt_offset,
7084        })
7085    }
7086
7087    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7088        if let Some(id) = anchor.text_anchor.buffer_id {
7089            return Some(id);
7090        }
7091        let excerpt = self.excerpt_containing(anchor..anchor)?;
7092        Some(excerpt.buffer_id())
7093    }
7094
7095    pub fn selections_in_range<'a>(
7096        &'a self,
7097        range: &'a Range<Anchor>,
7098        include_local: bool,
7099    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7100        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7101        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7102        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7103        cursor.seek(start_locator, Bias::Left);
7104        cursor
7105            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7106            .flat_map(move |excerpt| {
7107                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7108                if excerpt.id == range.start.excerpt_id {
7109                    query_range.start = range.start.text_anchor;
7110                }
7111                if excerpt.id == range.end.excerpt_id {
7112                    query_range.end = range.end.text_anchor;
7113                }
7114
7115                excerpt
7116                    .buffer
7117                    .selections_in_range(query_range, include_local)
7118                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7119                        selections.map(move |selection| {
7120                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7121                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7122                            if range.start.cmp(&start, self).is_gt() {
7123                                start = range.start;
7124                            }
7125                            if range.end.cmp(&end, self).is_lt() {
7126                                end = range.end;
7127                            }
7128
7129                            (
7130                                replica_id,
7131                                line_mode,
7132                                cursor_shape,
7133                                Selection {
7134                                    id: selection.id,
7135                                    start,
7136                                    end,
7137                                    reversed: selection.reversed,
7138                                    goal: selection.goal,
7139                                },
7140                            )
7141                        })
7142                    })
7143            })
7144    }
7145
7146    pub fn show_headers(&self) -> bool {
7147        self.show_headers
7148    }
7149
7150    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7151        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7152    }
7153
7154    pub fn all_diff_hunks_expanded(&self) -> bool {
7155        self.all_diff_hunks_expanded
7156    }
7157
7158    /// Visually annotates a position or range with the `Debug` representation of a value. The
7159    /// callsite of this function is used as a key - previous annotations will be removed.
7160    #[cfg(debug_assertions)]
7161    #[track_caller]
7162    pub fn debug<V, R>(&self, ranges: &R, value: V)
7163    where
7164        R: debug::ToMultiBufferDebugRanges,
7165        V: std::fmt::Debug,
7166    {
7167        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7168    }
7169
7170    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7171    /// debug annotations with the same key will be removed. The key is also used to determine the
7172    /// annotation's color.
7173    #[cfg(debug_assertions)]
7174    #[track_caller]
7175    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7176    where
7177        K: std::hash::Hash + 'static,
7178        R: debug::ToMultiBufferDebugRanges,
7179        V: std::fmt::Debug,
7180    {
7181        let text_ranges = ranges
7182            .to_multi_buffer_debug_ranges(self)
7183            .into_iter()
7184            .flat_map(|range| {
7185                self.range_to_buffer_ranges(range.start..=range.end)
7186                    .into_iter()
7187                    .map(|(buffer, range, _excerpt_id)| {
7188                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7189                    })
7190            })
7191            .collect();
7192        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7193            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7194        });
7195    }
7196
7197    fn excerpt_edits_for_diff_change(
7198        &self,
7199        buffer_state: &BufferState,
7200        diff_change_range: Range<usize>,
7201    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7202        let mut excerpt_edits = Vec::new();
7203        for locator in &buffer_state.excerpts {
7204            let mut cursor = self
7205                .excerpts
7206                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7207            cursor.seek_forward(&Some(locator), Bias::Left);
7208            if let Some(excerpt) = cursor.item()
7209                && excerpt.locator == *locator
7210            {
7211                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7212                if diff_change_range.end < excerpt_buffer_range.start
7213                    || diff_change_range.start > excerpt_buffer_range.end
7214                {
7215                    continue;
7216                }
7217                let excerpt_start = cursor.start().1;
7218                let excerpt_len = excerpt.text_summary.len;
7219                let diff_change_start_in_excerpt = diff_change_range
7220                    .start
7221                    .saturating_sub(excerpt_buffer_range.start);
7222                let diff_change_end_in_excerpt = diff_change_range
7223                    .end
7224                    .saturating_sub(excerpt_buffer_range.start);
7225                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7226                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7227                excerpt_edits.push(Edit {
7228                    old: edit_start..edit_end,
7229                    new: edit_start..edit_end,
7230                });
7231            }
7232        }
7233        excerpt_edits
7234    }
7235}
7236
7237#[cfg(any(test, feature = "test-support"))]
7238impl MultiBufferSnapshot {
7239    pub fn random_byte_range(
7240        &self,
7241        start_offset: MultiBufferOffset,
7242        rng: &mut impl rand::Rng,
7243    ) -> Range<MultiBufferOffset> {
7244        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7245        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7246        start..end
7247    }
7248
7249    #[cfg(any(test, feature = "test-support"))]
7250    fn check_invariants(&self) {
7251        let excerpts = self.excerpts.items(());
7252        let excerpt_ids = self.excerpt_ids.items(());
7253
7254        for (ix, excerpt) in excerpts.iter().enumerate() {
7255            if ix == 0 {
7256                if excerpt.locator <= Locator::min() {
7257                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7258                }
7259            } else if excerpt.locator <= excerpts[ix - 1].locator {
7260                panic!("excerpts are out-of-order: {:?}", excerpts);
7261            }
7262        }
7263
7264        for (ix, entry) in excerpt_ids.iter().enumerate() {
7265            if ix == 0 {
7266                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7267                    panic!("invalid first excerpt id {:?}", entry.id);
7268                }
7269            } else if entry.id <= excerpt_ids[ix - 1].id {
7270                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7271            }
7272        }
7273
7274        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7275            panic!(
7276                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7277                self.excerpts.summary().text,
7278                self.diff_transforms.summary().input,
7279                self.diff_transforms.items(()),
7280            );
7281        }
7282
7283        let mut prev_transform: Option<&DiffTransform> = None;
7284        for item in self.diff_transforms.iter() {
7285            if let DiffTransform::BufferContent {
7286                summary,
7287                inserted_hunk_info,
7288            } = item
7289            {
7290                if let Some(DiffTransform::BufferContent {
7291                    inserted_hunk_info: prev_inserted_hunk_info,
7292                    ..
7293                }) = prev_transform
7294                    && *inserted_hunk_info == *prev_inserted_hunk_info
7295                {
7296                    panic!(
7297                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7298                        self.diff_transforms.items(())
7299                    );
7300                }
7301                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7302                    panic!("empty buffer content transform");
7303                }
7304            }
7305            prev_transform = Some(item);
7306        }
7307    }
7308}
7309
7310impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7311where
7312    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7313    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7314{
7315    #[instrument(skip_all)]
7316    fn seek(&mut self, position: &MBD) {
7317        let position = OutputDimension(*position);
7318        self.cached_region.take();
7319        self.diff_transforms.seek(&position, Bias::Right);
7320        if self.diff_transforms.item().is_none()
7321            && self.diff_transforms.start().output_dimension == position
7322        {
7323            self.diff_transforms.prev();
7324        }
7325
7326        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7327        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7328            let overshoot = position - self.diff_transforms.start().output_dimension;
7329            excerpt_position += overshoot;
7330        }
7331
7332        self.excerpts.seek(&excerpt_position, Bias::Right);
7333        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7334            self.excerpts.prev();
7335        }
7336    }
7337
7338    fn seek_forward(&mut self, position: &MBD) {
7339        let position = OutputDimension(*position);
7340        self.cached_region.take();
7341        self.diff_transforms.seek_forward(&position, Bias::Right);
7342        if self.diff_transforms.item().is_none()
7343            && self.diff_transforms.start().output_dimension == position
7344        {
7345            self.diff_transforms.prev();
7346        }
7347
7348        let overshoot = position - self.diff_transforms.start().output_dimension;
7349        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7350        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7351            excerpt_position += overshoot;
7352        }
7353
7354        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7355        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7356            self.excerpts.prev();
7357        }
7358    }
7359
7360    fn next_excerpt(&mut self) {
7361        self.excerpts.next();
7362        self.seek_to_start_of_current_excerpt();
7363    }
7364
7365    fn prev_excerpt(&mut self) {
7366        self.excerpts.prev();
7367        self.seek_to_start_of_current_excerpt();
7368    }
7369
7370    fn seek_to_start_of_current_excerpt(&mut self) {
7371        self.cached_region.take();
7372
7373        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7374            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7375            && self.diff_transforms.next_item().is_some()
7376        {
7377            self.diff_transforms.next();
7378        }
7379    }
7380
7381    fn next_excerpt_forwards(&mut self) {
7382        self.excerpts.next();
7383        self.seek_to_start_of_current_excerpt_forward();
7384    }
7385
7386    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7387        self.cached_region.take();
7388
7389        if self
7390            .diff_transforms
7391            .seek_forward(self.excerpts.start(), Bias::Left)
7392            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7393            && self.diff_transforms.next_item().is_some()
7394        {
7395            self.diff_transforms.next();
7396        }
7397    }
7398
7399    fn next(&mut self) {
7400        self.cached_region.take();
7401        match self
7402            .diff_transforms
7403            .end()
7404            .excerpt_dimension
7405            .cmp(&self.excerpts.end())
7406        {
7407            cmp::Ordering::Less => self.diff_transforms.next(),
7408            cmp::Ordering::Greater => self.excerpts.next(),
7409            cmp::Ordering::Equal => {
7410                self.diff_transforms.next();
7411                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7412                    || self.diff_transforms.item().is_none()
7413                {
7414                    self.excerpts.next();
7415                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7416                    self.diff_transforms.item()
7417                    && self
7418                        .excerpts
7419                        .item()
7420                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7421                {
7422                    self.excerpts.next();
7423                }
7424            }
7425        }
7426    }
7427
7428    fn prev(&mut self) {
7429        self.cached_region.take();
7430        match self
7431            .diff_transforms
7432            .start()
7433            .excerpt_dimension
7434            .cmp(self.excerpts.start())
7435        {
7436            cmp::Ordering::Less => self.excerpts.prev(),
7437            cmp::Ordering::Greater => self.diff_transforms.prev(),
7438            cmp::Ordering::Equal => {
7439                self.diff_transforms.prev();
7440                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7441                    || self.diff_transforms.item().is_none()
7442                {
7443                    self.excerpts.prev();
7444                }
7445            }
7446        }
7447    }
7448
7449    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7450        self.cached_region
7451            .get_or_init(|| self.build_region())
7452            .as_ref()
7453    }
7454
7455    fn is_at_start_of_excerpt(&mut self) -> bool {
7456        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7457            return false;
7458        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7459            return true;
7460        }
7461
7462        self.diff_transforms.prev();
7463        let prev_transform = self.diff_transforms.item();
7464        self.diff_transforms.next();
7465
7466        prev_transform.is_none_or(|next_transform| {
7467            matches!(next_transform, DiffTransform::BufferContent { .. })
7468        })
7469    }
7470
7471    fn is_at_end_of_excerpt(&self) -> bool {
7472        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7473            return false;
7474        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7475            || self.diff_transforms.item().is_none()
7476        {
7477            return true;
7478        }
7479
7480        let next_transform = self.diff_transforms.next_item();
7481        next_transform.is_none_or(|next_transform| match next_transform {
7482            DiffTransform::BufferContent { .. } => true,
7483            DiffTransform::DeletedHunk { hunk_info, .. } => self
7484                .excerpts
7485                .item()
7486                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7487        })
7488    }
7489
7490    fn main_buffer_position(&self) -> Option<BD> {
7491        let excerpt = self.excerpts.item()?;
7492        let buffer = &excerpt.buffer;
7493        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7494        let mut buffer_start = buffer_context_start;
7495        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7496        buffer_start += overshoot;
7497        Some(buffer_start)
7498    }
7499
7500    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7501        let excerpt = self.excerpts.item()?;
7502        match self.diff_transforms.item()? {
7503            DiffTransform::DeletedHunk {
7504                buffer_id,
7505                base_text_byte_range,
7506                has_trailing_newline,
7507                hunk_info,
7508                ..
7509            } => {
7510                let diff = self.diffs.get(buffer_id)?;
7511                let buffer = diff.base_text();
7512                let mut rope_cursor = buffer.as_rope().cursor(0);
7513                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7514                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7515                let mut buffer_end = buffer_start;
7516                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7517                let start = self.diff_transforms.start().output_dimension.0;
7518                let end = self.diff_transforms.end().output_dimension.0;
7519                Some(MultiBufferRegion {
7520                    buffer,
7521                    excerpt,
7522                    has_trailing_newline: *has_trailing_newline,
7523                    is_main_buffer: false,
7524                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7525                        hunk_info.hunk_secondary_status,
7526                    )),
7527                    buffer_range: buffer_start..buffer_end,
7528                    range: start..end,
7529                })
7530            }
7531            DiffTransform::BufferContent {
7532                inserted_hunk_info, ..
7533            } => {
7534                let buffer = &excerpt.buffer;
7535                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7536
7537                let mut start = self.diff_transforms.start().output_dimension.0;
7538                let mut buffer_start = buffer_context_start;
7539                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7540                    let overshoot =
7541                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7542                    start += overshoot;
7543                } else {
7544                    let overshoot =
7545                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7546                    buffer_start += overshoot;
7547                }
7548
7549                let mut end;
7550                let mut buffer_end;
7551                let has_trailing_newline;
7552                let transform_end = self.diff_transforms.end();
7553                if transform_end.excerpt_dimension < self.excerpts.end() {
7554                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7555                    end = transform_end.output_dimension.0;
7556                    buffer_end = buffer_context_start;
7557                    buffer_end += overshoot;
7558                    has_trailing_newline = false;
7559                } else {
7560                    let overshoot =
7561                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7562                    end = self.diff_transforms.start().output_dimension.0;
7563                    end += overshoot;
7564                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7565                    has_trailing_newline = excerpt.has_trailing_newline;
7566                };
7567
7568                let diff_hunk_status = inserted_hunk_info.map(|info| {
7569                    if info.is_logically_deleted {
7570                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7571                    } else {
7572                        DiffHunkStatus::added(info.hunk_secondary_status)
7573                    }
7574                });
7575
7576                Some(MultiBufferRegion {
7577                    buffer,
7578                    excerpt,
7579                    has_trailing_newline,
7580                    is_main_buffer: true,
7581                    diff_hunk_status,
7582                    buffer_range: buffer_start..buffer_end,
7583                    range: start..end,
7584                })
7585            }
7586        }
7587    }
7588
7589    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7590        let excerpt = self.excerpts.item()?;
7591        match self.diff_transforms.item()? {
7592            &DiffTransform::DeletedHunk { .. } => {
7593                let start = self.diff_transforms.start().output_dimension.0;
7594                let end = self.diff_transforms.end().output_dimension.0;
7595                Some((excerpt, start..end))
7596            }
7597            DiffTransform::BufferContent { .. } => {
7598                let mut start = self.diff_transforms.start().output_dimension.0;
7599                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7600                    let overshoot =
7601                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7602                    start += overshoot;
7603                }
7604
7605                let mut end;
7606                let transform_end = self.diff_transforms.end();
7607                if transform_end.excerpt_dimension < self.excerpts.end() {
7608                    end = transform_end.output_dimension.0;
7609                } else {
7610                    let overshoot =
7611                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7612                    end = self.diff_transforms.start().output_dimension.0;
7613                    end += overshoot;
7614                };
7615
7616                Some((excerpt, start..end))
7617            }
7618        }
7619    }
7620
7621    fn excerpt(&self) -> Option<&'a Excerpt> {
7622        self.excerpts.item()
7623    }
7624}
7625
7626impl Excerpt {
7627    fn new(
7628        id: ExcerptId,
7629        locator: Locator,
7630        buffer_id: BufferId,
7631        buffer: Arc<BufferSnapshot>,
7632        range: ExcerptRange<text::Anchor>,
7633        has_trailing_newline: bool,
7634    ) -> Self {
7635        Excerpt {
7636            id,
7637            locator,
7638            max_buffer_row: range.context.end.to_point(&buffer).row,
7639            text_summary: buffer
7640                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7641            buffer_id,
7642            buffer,
7643            range,
7644            has_trailing_newline,
7645        }
7646    }
7647
7648    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7649        let content_start = self.range.context.start.to_offset(&self.buffer);
7650        let chunks_start = content_start + range.start;
7651        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7652
7653        let has_footer = self.has_trailing_newline
7654            && range.start <= self.text_summary.len
7655            && range.end > self.text_summary.len;
7656
7657        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7658
7659        ExcerptChunks {
7660            excerpt_id: self.id,
7661            content_chunks,
7662            has_footer,
7663        }
7664    }
7665
7666    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7667        let content_start = self.range.context.start.to_offset(&self.buffer);
7668        let chunks_start = content_start + range.start;
7669        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7670        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7671        excerpt_chunks.has_footer = self.has_trailing_newline
7672            && range.start <= self.text_summary.len
7673            && range.end > self.text_summary.len;
7674    }
7675
7676    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7677        if text_anchor
7678            .cmp(&self.range.context.start, &self.buffer)
7679            .is_lt()
7680        {
7681            self.range.context.start
7682        } else if text_anchor
7683            .cmp(&self.range.context.end, &self.buffer)
7684            .is_gt()
7685        {
7686            self.range.context.end
7687        } else {
7688            text_anchor
7689        }
7690    }
7691
7692    fn contains(&self, anchor: &Anchor) -> bool {
7693        (anchor.text_anchor.buffer_id == None
7694            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7695            && self
7696                .range
7697                .context
7698                .start
7699                .cmp(&anchor.text_anchor, &self.buffer)
7700                .is_le()
7701            && self
7702                .range
7703                .context
7704                .end
7705                .cmp(&anchor.text_anchor, &self.buffer)
7706                .is_ge()
7707    }
7708
7709    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7710    fn buffer_start_offset(&self) -> BufferOffset {
7711        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7712    }
7713
7714    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7715    fn buffer_end_offset(&self) -> BufferOffset {
7716        self.buffer_start_offset() + self.text_summary.len
7717    }
7718}
7719
7720impl<'a> MultiBufferExcerpt<'a> {
7721    pub fn id(&self) -> ExcerptId {
7722        self.excerpt.id
7723    }
7724
7725    pub fn buffer_id(&self) -> BufferId {
7726        self.excerpt.buffer_id
7727    }
7728
7729    pub fn start_anchor(&self) -> Anchor {
7730        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7731    }
7732
7733    pub fn end_anchor(&self) -> Anchor {
7734        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7735    }
7736
7737    pub fn buffer(&self) -> &'a BufferSnapshot {
7738        &self.excerpt.buffer
7739    }
7740
7741    pub fn buffer_range(&self) -> Range<BufferOffset> {
7742        self.buffer_offset
7743            ..BufferOffset(
7744                self.excerpt
7745                    .range
7746                    .context
7747                    .end
7748                    .to_offset(&self.excerpt.buffer.text),
7749            )
7750    }
7751
7752    pub fn start_offset(&self) -> MultiBufferOffset {
7753        self.offset
7754    }
7755
7756    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7757    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7758        self.map_range_to_buffer(offset..offset).start
7759    }
7760
7761    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7762    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7763        self.diff_transforms
7764            .seek(&OutputDimension(range.start), Bias::Right);
7765        let start = self.map_offset_to_buffer_internal(range.start);
7766        let end = if range.end > range.start {
7767            self.diff_transforms
7768                .seek_forward(&OutputDimension(range.end), Bias::Right);
7769            self.map_offset_to_buffer_internal(range.end)
7770        } else {
7771            start
7772        };
7773        start..end
7774    }
7775
7776    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7777        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7778        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7779            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7780        };
7781        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7782        self.buffer_offset + offset_in_excerpt
7783    }
7784
7785    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7786    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7787        self.map_range_from_buffer(buffer_offset..buffer_offset)
7788            .start
7789    }
7790
7791    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7792    pub fn map_range_from_buffer(
7793        &mut self,
7794        buffer_range: Range<BufferOffset>,
7795    ) -> Range<MultiBufferOffset> {
7796        if buffer_range.start < self.buffer_offset {
7797            log::warn!(
7798                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7799            );
7800            return self.offset..self.offset;
7801        }
7802        let overshoot = buffer_range.start - self.buffer_offset;
7803        let excerpt_offset = self.excerpt_offset + overshoot;
7804        let excerpt_seek_dim = excerpt_offset;
7805        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7806        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7807            log::warn!(
7808                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7809            );
7810            return self.offset..self.offset;
7811        }
7812        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7813        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7814
7815        let end = if buffer_range.start < buffer_range.end {
7816            let overshoot = buffer_range.end - self.buffer_offset;
7817            let excerpt_offset = self.excerpt_offset + overshoot;
7818            let excerpt_seek_dim = excerpt_offset;
7819            self.diff_transforms
7820                .seek_forward(&excerpt_seek_dim, Bias::Right);
7821            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7822            // todo(lw): Clamp end to the excerpt boundaries
7823            self.diff_transforms.start().output_dimension.0 + overshoot
7824        } else {
7825            start
7826        };
7827
7828        start..end
7829    }
7830
7831    /// Returns true if the entirety of the given range is in the buffer's excerpt
7832    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7833        range.start >= self.excerpt.buffer_start_offset()
7834            && range.end <= self.excerpt.buffer_end_offset()
7835    }
7836
7837    /// Returns true if any part of the given range is in the buffer's excerpt
7838    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7839        range.start <= self.excerpt.buffer_end_offset()
7840            && range.end >= self.excerpt.buffer_start_offset()
7841    }
7842
7843    pub fn max_buffer_row(&self) -> u32 {
7844        self.excerpt.max_buffer_row
7845    }
7846}
7847
7848impl ExcerptId {
7849    pub fn min() -> Self {
7850        Self(0)
7851    }
7852
7853    pub fn max() -> Self {
7854        Self(u32::MAX)
7855    }
7856
7857    pub fn to_proto(self) -> u64 {
7858        self.0 as _
7859    }
7860
7861    pub fn from_proto(proto: u64) -> Self {
7862        Self(proto as _)
7863    }
7864
7865    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7866        let a = snapshot.excerpt_locator_for_id(*self);
7867        let b = snapshot.excerpt_locator_for_id(*other);
7868        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7869    }
7870}
7871
7872impl From<ExcerptId> for usize {
7873    fn from(val: ExcerptId) -> Self {
7874        val.0 as usize
7875    }
7876}
7877
7878impl fmt::Debug for Excerpt {
7879    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7880        f.debug_struct("Excerpt")
7881            .field("id", &self.id)
7882            .field("locator", &self.locator)
7883            .field("buffer_id", &self.buffer_id)
7884            .field("range", &self.range)
7885            .field("text_summary", &self.text_summary)
7886            .field("has_trailing_newline", &self.has_trailing_newline)
7887            .finish()
7888    }
7889}
7890
7891impl sum_tree::Item for Excerpt {
7892    type Summary = ExcerptSummary;
7893
7894    fn summary(&self, _cx: ()) -> Self::Summary {
7895        let mut text = self.text_summary;
7896        if self.has_trailing_newline {
7897            text += TextSummary::from("\n");
7898        }
7899        ExcerptSummary {
7900            excerpt_id: self.id,
7901            excerpt_locator: self.locator.clone(),
7902            widest_line_number: self.max_buffer_row,
7903            text: text.into(),
7904            count: 1,
7905        }
7906    }
7907}
7908
7909impl sum_tree::Item for ExcerptIdMapping {
7910    type Summary = ExcerptId;
7911
7912    fn summary(&self, _cx: ()) -> Self::Summary {
7913        self.id
7914    }
7915}
7916
7917impl sum_tree::KeyedItem for ExcerptIdMapping {
7918    type Key = ExcerptId;
7919
7920    fn key(&self) -> Self::Key {
7921        self.id
7922    }
7923}
7924
7925impl DiffTransform {
7926    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7927        match self {
7928            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7929            DiffTransform::BufferContent {
7930                inserted_hunk_info, ..
7931            } => *inserted_hunk_info,
7932        }
7933    }
7934}
7935
7936impl sum_tree::Item for DiffTransform {
7937    type Summary = DiffTransformSummary;
7938
7939    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7940        match self {
7941            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7942                input: *summary,
7943                output: *summary,
7944            },
7945            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7946                input: MBTextSummary::default(),
7947                output: summary.into(),
7948            },
7949        }
7950    }
7951}
7952
7953impl DiffTransformSummary {
7954    fn excerpt_len(&self) -> ExcerptOffset {
7955        ExcerptDimension(self.input.len)
7956    }
7957}
7958
7959impl sum_tree::ContextLessSummary for DiffTransformSummary {
7960    fn zero() -> Self {
7961        DiffTransformSummary {
7962            input: MBTextSummary::default(),
7963            output: MBTextSummary::default(),
7964        }
7965    }
7966
7967    fn add_summary(&mut self, other: &Self) {
7968        self.input += other.input;
7969        self.output += other.output;
7970    }
7971}
7972
7973impl sum_tree::ContextLessSummary for ExcerptId {
7974    fn zero() -> Self {
7975        Self(0)
7976    }
7977
7978    fn add_summary(&mut self, summary: &Self) {
7979        *self = cmp::max(*self, *summary);
7980    }
7981}
7982
7983impl sum_tree::ContextLessSummary for ExcerptSummary {
7984    fn zero() -> Self {
7985        Self::default()
7986    }
7987
7988    fn add_summary(&mut self, summary: &Self) {
7989        debug_assert!(
7990            summary.excerpt_locator > self.excerpt_locator
7991                || self.excerpt_locator == Locator::min(),
7992            "Excerpt locators must be in ascending order: {:?} > {:?}",
7993            summary.excerpt_locator,
7994            self.excerpt_locator
7995        );
7996        self.excerpt_locator = summary.excerpt_locator.clone();
7997        self.text += summary.text;
7998        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7999        self.count += summary.count;
8000    }
8001}
8002
8003impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8004    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8005        Ord::cmp(&Some(self), cursor_location)
8006    }
8007}
8008
8009impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8010    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8011        Ord::cmp(self, &cursor_location.excerpt_locator)
8012    }
8013}
8014
8015impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8016where
8017    MBD: MultiBufferDimension + Default,
8018{
8019    fn zero(_: ()) -> Self {
8020        ExcerptDimension(MBD::default())
8021    }
8022
8023    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8024        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8025    }
8026}
8027
8028impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8029    fn zero(_cx: ()) -> Self {
8030        Default::default()
8031    }
8032
8033    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8034        *self = Some(&summary.excerpt_locator);
8035    }
8036}
8037
8038impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8039    fn zero(_cx: ()) -> Self {
8040        Default::default()
8041    }
8042
8043    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8044        *self = Some(summary.excerpt_id);
8045    }
8046}
8047
8048#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8049struct OutputDimension<T>(T);
8050
8051impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8052    fn eq(&self, other: &T) -> bool {
8053        self.0 == *other
8054    }
8055}
8056
8057impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8058    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8059        self.0.partial_cmp(other)
8060    }
8061}
8062
8063impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8064where
8065    T: ops::Sub<U, Output = R>,
8066{
8067    type Output = R;
8068
8069    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8070        self.0 - other.0
8071    }
8072}
8073
8074impl<R, T, U> ops::Add<U> for OutputDimension<T>
8075where
8076    T: ops::Add<U, Output = R>,
8077{
8078    type Output = OutputDimension<R>;
8079
8080    fn add(self, other: U) -> Self::Output {
8081        OutputDimension(self.0 + other)
8082    }
8083}
8084
8085impl<T, U> AddAssign<U> for OutputDimension<T>
8086where
8087    T: AddAssign<U>,
8088{
8089    fn add_assign(&mut self, other: U) {
8090        self.0 += other;
8091    }
8092}
8093
8094impl<T, U> SubAssign<U> for OutputDimension<T>
8095where
8096    T: SubAssign<U>,
8097{
8098    fn sub_assign(&mut self, other: U) {
8099        self.0 -= other;
8100    }
8101}
8102
8103#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8104struct ExcerptDimension<T>(T);
8105
8106impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8107    fn eq(&self, other: &T) -> bool {
8108        self.0 == *other
8109    }
8110}
8111
8112impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8113    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8114        self.0.partial_cmp(other)
8115    }
8116}
8117
8118impl ExcerptOffset {
8119    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8120        self.0.saturating_sub(other.0)
8121    }
8122}
8123
8124impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8125where
8126    T: ops::Sub<U, Output = R>,
8127{
8128    type Output = R;
8129
8130    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8131        self.0 - other.0
8132    }
8133}
8134
8135impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8136where
8137    T: ops::Add<U, Output = R>,
8138{
8139    type Output = ExcerptDimension<R>;
8140
8141    fn add(self, other: U) -> Self::Output {
8142        ExcerptDimension(self.0 + other)
8143    }
8144}
8145
8146impl<T, U> AddAssign<U> for ExcerptDimension<T>
8147where
8148    T: AddAssign<U>,
8149{
8150    fn add_assign(&mut self, other: U) {
8151        self.0 += other;
8152    }
8153}
8154
8155impl<T, U> SubAssign<U> for ExcerptDimension<T>
8156where
8157    T: SubAssign<U>,
8158{
8159    fn sub_assign(&mut self, other: U) {
8160        self.0 -= other;
8161    }
8162}
8163
8164impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8165    fn zero(_: ()) -> Self {
8166        MultiBufferOffset::ZERO
8167    }
8168
8169    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8170        *self += summary.output.len;
8171    }
8172}
8173
8174impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8175    for ExcerptDimension<MBD>
8176where
8177    MBD: MultiBufferDimension + Ord,
8178{
8179    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8180        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8181    }
8182}
8183
8184impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8185    for ExcerptDimension<MBD>
8186where
8187    MBD: MultiBufferDimension + Ord,
8188{
8189    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8190        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8191    }
8192}
8193
8194impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8195    for ExcerptDimension<MBD>
8196{
8197    fn zero(_: ()) -> Self {
8198        ExcerptDimension(MBD::default())
8199    }
8200
8201    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8202        self.0.add_mb_text_summary(&summary.input)
8203    }
8204}
8205
8206impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8207    for OutputDimension<MBD>
8208where
8209    MBD: MultiBufferDimension + Ord,
8210{
8211    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8212        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8213    }
8214}
8215
8216impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8217    for OutputDimension<MBD>
8218{
8219    fn zero(_: ()) -> Self {
8220        OutputDimension(MBD::default())
8221    }
8222
8223    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8224        self.0.add_mb_text_summary(&summary.output)
8225    }
8226}
8227
8228impl MultiBufferRows<'_> {
8229    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8230        self.point = Point::new(row, 0);
8231        self.cursor.seek(&self.point);
8232    }
8233}
8234
8235impl Iterator for MultiBufferRows<'_> {
8236    type Item = RowInfo;
8237
8238    fn next(&mut self) -> Option<Self::Item> {
8239        if self.is_empty && self.point.row == 0 {
8240            self.point += Point::new(1, 0);
8241            return Some(RowInfo {
8242                buffer_id: None,
8243                buffer_row: Some(0),
8244                multibuffer_row: Some(MultiBufferRow(0)),
8245                diff_status: None,
8246                expand_info: None,
8247                wrapped_buffer_row: None,
8248            });
8249        }
8250
8251        let mut region = self.cursor.region()?.clone();
8252        while self.point >= region.range.end {
8253            self.cursor.next();
8254            if let Some(next_region) = self.cursor.region() {
8255                region = next_region.clone();
8256            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8257                let multibuffer_row = MultiBufferRow(self.point.row);
8258                let last_excerpt = self
8259                    .cursor
8260                    .excerpts
8261                    .item()
8262                    .or(self.cursor.excerpts.prev_item())?;
8263                let last_row = last_excerpt
8264                    .range
8265                    .context
8266                    .end
8267                    .to_point(&last_excerpt.buffer)
8268                    .row;
8269
8270                let first_row = last_excerpt
8271                    .range
8272                    .context
8273                    .start
8274                    .to_point(&last_excerpt.buffer)
8275                    .row;
8276
8277                let expand_info = if self.is_singleton {
8278                    None
8279                } else {
8280                    let needs_expand_up = first_row == last_row
8281                        && last_row > 0
8282                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8283                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8284
8285                    if needs_expand_up && needs_expand_down {
8286                        Some(ExpandExcerptDirection::UpAndDown)
8287                    } else if needs_expand_up {
8288                        Some(ExpandExcerptDirection::Up)
8289                    } else if needs_expand_down {
8290                        Some(ExpandExcerptDirection::Down)
8291                    } else {
8292                        None
8293                    }
8294                    .map(|direction| ExpandInfo {
8295                        direction,
8296                        excerpt_id: last_excerpt.id,
8297                    })
8298                };
8299                self.point += Point::new(1, 0);
8300                return Some(RowInfo {
8301                    buffer_id: Some(last_excerpt.buffer_id),
8302                    buffer_row: Some(last_row),
8303                    multibuffer_row: Some(multibuffer_row),
8304                    diff_status: None,
8305                    wrapped_buffer_row: None,
8306                    expand_info,
8307                });
8308            } else {
8309                return None;
8310            };
8311        }
8312
8313        let overshoot = self.point - region.range.start;
8314        let buffer_point = region.buffer_range.start + overshoot;
8315        let expand_info = if self.is_singleton {
8316            None
8317        } else {
8318            let needs_expand_up = self.point.row == region.range.start.row
8319                && self.cursor.is_at_start_of_excerpt()
8320                && buffer_point.row > 0;
8321            let needs_expand_down = (region.excerpt.has_trailing_newline
8322                && self.point.row + 1 == region.range.end.row
8323                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8324                && self.cursor.is_at_end_of_excerpt()
8325                && buffer_point.row < region.buffer.max_point().row;
8326
8327            if needs_expand_up && needs_expand_down {
8328                Some(ExpandExcerptDirection::UpAndDown)
8329            } else if needs_expand_up {
8330                Some(ExpandExcerptDirection::Up)
8331            } else if needs_expand_down {
8332                Some(ExpandExcerptDirection::Down)
8333            } else {
8334                None
8335            }
8336            .map(|direction| ExpandInfo {
8337                direction,
8338                excerpt_id: region.excerpt.id,
8339            })
8340        };
8341
8342        let result = Some(RowInfo {
8343            buffer_id: Some(region.buffer.remote_id()),
8344            buffer_row: Some(buffer_point.row),
8345            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8346            diff_status: region
8347                .diff_hunk_status
8348                .filter(|_| self.point < region.range.end),
8349            expand_info,
8350            wrapped_buffer_row: None,
8351        });
8352        self.point += Point::new(1, 0);
8353        result
8354    }
8355}
8356
8357impl<'a> MultiBufferChunks<'a> {
8358    pub fn offset(&self) -> MultiBufferOffset {
8359        self.range.start
8360    }
8361
8362    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8363        self.diff_transforms.seek(&range.end, Bias::Right);
8364        let mut excerpt_end = self.diff_transforms.start().1;
8365        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8366            let overshoot = range.end - self.diff_transforms.start().0;
8367            excerpt_end += overshoot;
8368        }
8369
8370        self.diff_transforms.seek(&range.start, Bias::Right);
8371        let mut excerpt_start = self.diff_transforms.start().1;
8372        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8373            let overshoot = range.start - self.diff_transforms.start().0;
8374            excerpt_start += overshoot;
8375        }
8376
8377        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8378        self.buffer_chunk.take();
8379        self.range = range;
8380    }
8381
8382    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8383        self.excerpt_offset_range = new_range.clone();
8384        self.excerpts.seek(&new_range.start, Bias::Right);
8385        if let Some(excerpt) = self.excerpts.item() {
8386            let excerpt_start = *self.excerpts.start();
8387            if let Some(excerpt_chunks) = self
8388                .excerpt_chunks
8389                .as_mut()
8390                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8391            {
8392                excerpt.seek_chunks(
8393                    excerpt_chunks,
8394                    (self.excerpt_offset_range.start - excerpt_start)
8395                        ..(self.excerpt_offset_range.end - excerpt_start),
8396                );
8397            } else {
8398                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8399                    (self.excerpt_offset_range.start - excerpt_start)
8400                        ..(self.excerpt_offset_range.end - excerpt_start),
8401                    self.language_aware,
8402                ));
8403            }
8404        } else {
8405            self.excerpt_chunks = None;
8406        }
8407    }
8408
8409    #[ztracing::instrument(skip_all)]
8410    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8411        loop {
8412            if self.excerpt_offset_range.is_empty() {
8413                return None;
8414            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8415                self.excerpt_offset_range.start += chunk.text.len();
8416                return Some(chunk);
8417            } else {
8418                self.excerpts.next();
8419                let excerpt = self.excerpts.item()?;
8420                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8421                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8422                    self.language_aware,
8423                ));
8424            }
8425        }
8426    }
8427}
8428
8429impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8430    type Item = &'a str;
8431
8432    fn next(&mut self) -> Option<Self::Item> {
8433        let mut region = self.cursor.region()?;
8434        if self.offset == region.range.start {
8435            self.cursor.prev();
8436            region = self.cursor.region()?;
8437            let start_overshoot = self.start.saturating_sub(region.range.start);
8438            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8439                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8440            ));
8441        }
8442
8443        if self.offset == region.range.end && region.has_trailing_newline {
8444            self.offset -= 1;
8445            Some("\n")
8446        } else {
8447            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8448            self.offset -= chunk.len();
8449            Some(chunk)
8450        }
8451    }
8452}
8453
8454impl<'a> Iterator for MultiBufferChunks<'a> {
8455    type Item = Chunk<'a>;
8456
8457    #[ztracing::instrument(skip_all)]
8458    fn next(&mut self) -> Option<Chunk<'a>> {
8459        if self.range.start >= self.range.end {
8460            return None;
8461        }
8462        if self.range.start == self.diff_transforms.end().0 {
8463            self.diff_transforms.next();
8464        }
8465
8466        let diff_transform_start = self.diff_transforms.start().0;
8467        let diff_transform_end = self.diff_transforms.end().0;
8468        debug_assert!(
8469            self.range.start < diff_transform_end,
8470            "{:?} < {:?} of ({1:?}..{2:?})",
8471            self.range.start,
8472            diff_transform_end,
8473            diff_transform_start
8474        );
8475
8476        let diff_transform = self.diff_transforms.item()?;
8477        match diff_transform {
8478            DiffTransform::BufferContent { .. } => {
8479                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8480                    chunk
8481                } else {
8482                    let chunk = self.next_excerpt_chunk().unwrap();
8483                    self.buffer_chunk.insert(chunk)
8484                };
8485
8486                let chunk_end = self.range.start + chunk.text.len();
8487                let diff_transform_end = diff_transform_end.min(self.range.end);
8488
8489                if diff_transform_end < chunk_end {
8490                    let split_idx = diff_transform_end - self.range.start;
8491                    let (before, after) = chunk.text.split_at(split_idx);
8492                    self.range.start = diff_transform_end;
8493                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8494                    let chars = chunk.chars & mask;
8495                    let tabs = chunk.tabs & mask;
8496                    let newlines = chunk.newlines & mask;
8497
8498                    chunk.text = after;
8499                    chunk.chars = chunk.chars >> split_idx;
8500                    chunk.tabs = chunk.tabs >> split_idx;
8501                    chunk.newlines = chunk.newlines >> split_idx;
8502
8503                    Some(Chunk {
8504                        text: before,
8505                        chars,
8506                        tabs,
8507                        newlines,
8508                        ..chunk.clone()
8509                    })
8510                } else {
8511                    self.range.start = chunk_end;
8512                    self.buffer_chunk.take()
8513                }
8514            }
8515            DiffTransform::DeletedHunk {
8516                buffer_id,
8517                base_text_byte_range,
8518                has_trailing_newline,
8519                ..
8520            } => {
8521                let base_text_start =
8522                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8523                let base_text_end =
8524                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8525                let base_text_end = base_text_end.min(base_text_byte_range.end);
8526
8527                let mut chunks = if let Some((_, mut chunks)) = self
8528                    .diff_base_chunks
8529                    .take()
8530                    .filter(|(id, _)| id == buffer_id)
8531                {
8532                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8533                    {
8534                        chunks.seek(base_text_start..base_text_end);
8535                    }
8536                    chunks
8537                } else {
8538                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8539                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8540                };
8541
8542                let chunk = if let Some(chunk) = chunks.next() {
8543                    self.range.start += chunk.text.len();
8544                    self.diff_base_chunks = Some((*buffer_id, chunks));
8545                    chunk
8546                } else {
8547                    debug_assert!(has_trailing_newline);
8548                    self.range.start += "\n".len();
8549                    Chunk {
8550                        text: "\n",
8551                        chars: 1u128,
8552                        newlines: 1u128,
8553                        ..Default::default()
8554                    }
8555                };
8556                Some(chunk)
8557            }
8558        }
8559    }
8560}
8561
8562impl MultiBufferBytes<'_> {
8563    fn consume(&mut self, len: usize) {
8564        self.range.start += len;
8565        self.chunk = &self.chunk[len..];
8566
8567        if !self.range.is_empty() && self.chunk.is_empty() {
8568            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8569                self.chunk = chunk;
8570            } else if self.has_trailing_newline {
8571                self.has_trailing_newline = false;
8572                self.chunk = b"\n";
8573            } else {
8574                self.cursor.next();
8575                if let Some(region) = self.cursor.region() {
8576                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8577                        region.buffer_range.start
8578                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8579                                .min(region.buffer_range.end),
8580                    );
8581                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8582                    self.excerpt_bytes = Some(excerpt_bytes);
8583                    self.has_trailing_newline =
8584                        region.has_trailing_newline && self.range.end >= region.range.end;
8585                    if self.chunk.is_empty() && self.has_trailing_newline {
8586                        self.has_trailing_newline = false;
8587                        self.chunk = b"\n";
8588                    }
8589                }
8590            }
8591        }
8592    }
8593}
8594
8595impl<'a> Iterator for MultiBufferBytes<'a> {
8596    type Item = &'a [u8];
8597
8598    fn next(&mut self) -> Option<Self::Item> {
8599        let chunk = self.chunk;
8600        if chunk.is_empty() {
8601            None
8602        } else {
8603            self.consume(chunk.len());
8604            Some(chunk)
8605        }
8606    }
8607}
8608
8609impl io::Read for MultiBufferBytes<'_> {
8610    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8611        let len = cmp::min(buf.len(), self.chunk.len());
8612        buf[..len].copy_from_slice(&self.chunk[..len]);
8613        if len > 0 {
8614            self.consume(len);
8615        }
8616        Ok(len)
8617    }
8618}
8619
8620impl io::Read for ReversedMultiBufferBytes<'_> {
8621    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8622        let len = cmp::min(buf.len(), self.chunk.len());
8623        buf[..len].copy_from_slice(&self.chunk[..len]);
8624        buf[..len].reverse();
8625        if len > 0 {
8626            self.range.end -= len;
8627            self.chunk = &self.chunk[..self.chunk.len() - len];
8628            if !self.range.is_empty()
8629                && self.chunk.is_empty()
8630                && let Some(chunk) = self.chunks.next()
8631            {
8632                self.chunk = chunk.as_bytes();
8633            }
8634        }
8635        Ok(len)
8636    }
8637}
8638
8639impl<'a> Iterator for ExcerptChunks<'a> {
8640    type Item = Chunk<'a>;
8641
8642    fn next(&mut self) -> Option<Self::Item> {
8643        if let Some(chunk) = self.content_chunks.next() {
8644            return Some(chunk);
8645        }
8646
8647        if self.has_footer {
8648            let text = "\n";
8649            let chars = 0b1;
8650            let newlines = 0b1;
8651            self.has_footer = false;
8652            return Some(Chunk {
8653                text,
8654                chars,
8655                newlines,
8656                ..Default::default()
8657            });
8658        }
8659
8660        None
8661    }
8662}
8663
8664impl ToOffset for Point {
8665    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8666        snapshot.point_to_offset(*self)
8667    }
8668    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8669        snapshot.point_to_offset_utf16(*self)
8670    }
8671}
8672
8673impl ToOffset for MultiBufferOffset {
8674    #[track_caller]
8675    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8676        assert!(
8677            *self <= snapshot.len(),
8678            "offset {} is greater than the snapshot.len() {}",
8679            self.0,
8680            snapshot.len().0,
8681        );
8682        *self
8683    }
8684    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8685        snapshot.offset_to_offset_utf16(*self)
8686    }
8687}
8688
8689impl ToOffset for MultiBufferOffsetUtf16 {
8690    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8691        snapshot.offset_utf16_to_offset(*self)
8692    }
8693
8694    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8695        *self
8696    }
8697}
8698
8699impl ToOffset for PointUtf16 {
8700    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8701        snapshot.point_utf16_to_offset(*self)
8702    }
8703    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8704        snapshot.point_utf16_to_offset_utf16(*self)
8705    }
8706}
8707
8708impl ToPoint for MultiBufferOffset {
8709    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8710        snapshot.offset_to_point(*self)
8711    }
8712    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8713        snapshot.offset_to_point_utf16(*self)
8714    }
8715}
8716
8717impl ToPoint for Point {
8718    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8719        *self
8720    }
8721    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8722        snapshot.point_to_point_utf16(*self)
8723    }
8724}
8725
8726impl ToPoint for PointUtf16 {
8727    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8728        snapshot.point_utf16_to_point(*self)
8729    }
8730    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8731        *self
8732    }
8733}
8734
8735impl From<ExcerptId> for EntityId {
8736    fn from(id: ExcerptId) -> Self {
8737        EntityId::from(id.0 as u64)
8738    }
8739}
8740
8741#[cfg(debug_assertions)]
8742pub mod debug {
8743    use super::*;
8744
8745    pub trait ToMultiBufferDebugRanges {
8746        fn to_multi_buffer_debug_ranges(
8747            &self,
8748            snapshot: &MultiBufferSnapshot,
8749        ) -> Vec<Range<MultiBufferOffset>>;
8750    }
8751
8752    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8753        fn to_multi_buffer_debug_ranges(
8754            &self,
8755            snapshot: &MultiBufferSnapshot,
8756        ) -> Vec<Range<MultiBufferOffset>> {
8757            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8758        }
8759    }
8760
8761    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8762        fn to_multi_buffer_debug_ranges(
8763            &self,
8764            snapshot: &MultiBufferSnapshot,
8765        ) -> Vec<Range<MultiBufferOffset>> {
8766            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8767                .to_multi_buffer_debug_ranges(snapshot)
8768        }
8769    }
8770
8771    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8772        fn to_multi_buffer_debug_ranges(
8773            &self,
8774            snapshot: &MultiBufferSnapshot,
8775        ) -> Vec<Range<MultiBufferOffset>> {
8776            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8777        }
8778    }
8779
8780    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8781        fn to_multi_buffer_debug_ranges(
8782            &self,
8783            snapshot: &MultiBufferSnapshot,
8784        ) -> Vec<Range<MultiBufferOffset>> {
8785            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8786        }
8787    }
8788
8789    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8790        fn to_multi_buffer_debug_ranges(
8791            &self,
8792            snapshot: &MultiBufferSnapshot,
8793        ) -> Vec<Range<MultiBufferOffset>> {
8794            self.iter()
8795                .map(|item| {
8796                    let offset = item.to_offset(snapshot);
8797                    offset..offset
8798                })
8799                .collect()
8800        }
8801    }
8802
8803    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8804        fn to_multi_buffer_debug_ranges(
8805            &self,
8806            snapshot: &MultiBufferSnapshot,
8807        ) -> Vec<Range<MultiBufferOffset>> {
8808            self.iter()
8809                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8810                .collect()
8811        }
8812    }
8813}