multi_buffer.rs

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