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::{
  10    Anchor, AnchorHasDiffbaseError, AnchorRangeExt, DiffbaselessAnchor, DiffbaselessAnchorRangeExt,
  11};
  12
  13use anyhow::{Result, anyhow};
  14use buffer_diff::{
  15    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunk,
  16    DiffHunkSecondaryStatus, DiffHunkStatus, DiffHunkStatusKind,
  17};
  18use clock::ReplicaId;
  19use collections::{BTreeMap, Bound, HashMap, HashSet};
  20use gpui::{App, Context, Entity, EntityId, EventEmitter};
  21use itertools::Itertools;
  22use language::{
  23    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  24    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  25    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  26    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  27    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  28    language_settings::{LanguageSettings, language_settings},
  29};
  30
  31#[cfg(any(test, feature = "test-support"))]
  32use gpui::AppContext as _;
  33
  34use rope::DimensionPair;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, OnceCell, Ref, RefCell},
  41    cmp, fmt,
  42    future::Future,
  43    io,
  44    iter::{self, FromIterator},
  45    mem,
  46    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  47    rc::Rc,
  48    str,
  49    sync::{Arc, OnceLock},
  50    time::Duration,
  51};
  52use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  53use text::{
  54    BufferId, Edit, LineIndent, TextSummary,
  55    locator::Locator,
  56    subscription::{Subscription, Topic},
  57};
  58use theme::SyntaxTheme;
  59use util::post_inc;
  60use ztracing::instrument;
  61
  62pub use self::path_key::PathKey;
  63
  64pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  65
  66pub fn excerpt_context_lines(cx: &App) -> u32 {
  67    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  68}
  69
  70#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  71pub struct ExcerptId(u32);
  72
  73/// One or more [`Buffers`](Buffer) being edited in a single view.
  74///
  75/// See <https://zed.dev/features#multi-buffers>
  76pub struct MultiBuffer {
  77    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  78    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  79    snapshot: RefCell<MultiBufferSnapshot>,
  80    /// Contains the state of the buffers being edited
  81    buffers: BTreeMap<BufferId, BufferState>,
  82    /// Mapping from path keys to their excerpts.
  83    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  84    /// Mapping from excerpt IDs to their path key.
  85    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  86    /// Mapping from buffer IDs to their diff states
  87    diffs: HashMap<BufferId, DiffState>,
  88    subscriptions: Topic<MultiBufferOffset>,
  89    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  90    singleton: bool,
  91    /// The history of the multi-buffer.
  92    history: History,
  93    /// The explicit title of the multi-buffer.
  94    /// If `None`, it will be derived from the underlying path or content.
  95    title: Option<String>,
  96    /// The writing capability of the multi-buffer.
  97    capability: Capability,
  98    buffer_changed_since_sync: Rc<Cell<bool>>,
  99}
 100
 101#[derive(Clone, Debug, PartialEq, Eq)]
 102pub enum Event {
 103    ExcerptsAdded {
 104        buffer: Entity<Buffer>,
 105        predecessor: ExcerptId,
 106        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 107    },
 108    ExcerptsRemoved {
 109        ids: Vec<ExcerptId>,
 110        removed_buffer_ids: Vec<BufferId>,
 111    },
 112    ExcerptsExpanded {
 113        ids: Vec<ExcerptId>,
 114    },
 115    ExcerptsEdited {
 116        excerpt_ids: Vec<ExcerptId>,
 117        buffer_ids: Vec<BufferId>,
 118    },
 119    DiffHunksToggled,
 120    Edited {
 121        edited_buffer: Option<Entity<Buffer>>,
 122    },
 123    TransactionUndone {
 124        transaction_id: TransactionId,
 125    },
 126    Reloaded,
 127    LanguageChanged(BufferId, bool),
 128    Reparsed(BufferId),
 129    Saved,
 130    FileHandleChanged,
 131    DirtyChanged,
 132    DiagnosticsUpdated,
 133    BufferDiffChanged,
 134}
 135
 136/// A diff hunk, representing a range of consequent lines in a multibuffer.
 137#[derive(Debug, Clone, PartialEq, Eq)]
 138pub struct MultiBufferDiffHunk {
 139    /// The row range in the multibuffer where this diff hunk appears.
 140    pub row_range: Range<MultiBufferRow>,
 141    /// The buffer ID that this hunk belongs to.
 142    pub buffer_id: BufferId,
 143    /// The range of the underlying buffer that this hunk corresponds to.
 144    pub buffer_range: Range<text::Anchor>,
 145    /// The excerpt that contains the diff hunk.
 146    pub excerpt_id: ExcerptId,
 147    /// The range within the buffer's diff base that this hunk corresponds to.
 148    pub diff_base_byte_range: Range<BufferOffset>,
 149    /// The status of this hunk (added/modified/deleted and secondary status).
 150    pub status: DiffHunkStatus,
 151    /// The word diffs for this hunk.
 152    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 153    pub staged_rows: Vec<MultiBufferRow>,
 154}
 155
 156impl MultiBufferDiffHunk {
 157    pub fn status(&self) -> DiffHunkStatus {
 158        self.status
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 163            && self.buffer_range.start.is_min()
 164            && self.buffer_range.end.is_max()
 165    }
 166
 167    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 168        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 169        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 170        start..end
 171    }
 172}
 173
 174pub type MultiBufferPoint = Point;
 175type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 176type ExcerptPoint = ExcerptDimension<Point>;
 177
 178#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 179#[serde(transparent)]
 180pub struct MultiBufferRow(pub u32);
 181
 182impl MultiBufferRow {
 183    pub const MIN: Self = Self(0);
 184    pub const MAX: Self = Self(u32::MAX);
 185}
 186
 187impl ops::Add<usize> for MultiBufferRow {
 188    type Output = Self;
 189
 190    fn add(self, rhs: usize) -> Self::Output {
 191        MultiBufferRow(self.0 + rhs as u32)
 192    }
 193}
 194
 195pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 196    type TextDimension: TextDimension;
 197    fn from_summary(summary: &MBTextSummary) -> Self;
 198
 199    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 200
 201    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 202}
 203
 204// todo(lw): MultiBufferPoint
 205impl MultiBufferDimension for Point {
 206    type TextDimension = Point;
 207    fn from_summary(summary: &MBTextSummary) -> Self {
 208        summary.lines
 209    }
 210
 211    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 212        *self += *other;
 213    }
 214
 215    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 216        *self += summary.lines;
 217    }
 218}
 219
 220// todo(lw): MultiBufferPointUtf16
 221impl MultiBufferDimension for PointUtf16 {
 222    type TextDimension = PointUtf16;
 223    fn from_summary(summary: &MBTextSummary) -> Self {
 224        summary.lines_utf16()
 225    }
 226
 227    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 228        *self += *other;
 229    }
 230
 231    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 232        *self += summary.lines_utf16();
 233    }
 234}
 235
 236#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 237pub struct MultiBufferOffset(pub usize);
 238
 239impl fmt::Display for MultiBufferOffset {
 240    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 241        write!(f, "{}", self.0)
 242    }
 243}
 244
 245impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 246    type Sampler = MultiBufferOffsetUniformSampler;
 247}
 248
 249pub struct MultiBufferOffsetUniformSampler {
 250    sampler: rand::distr::uniform::UniformUsize,
 251}
 252
 253impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 254    type X = MultiBufferOffset;
 255
 256    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 257    where
 258        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 260    {
 261        let low = *low_b.borrow();
 262        let high = *high_b.borrow();
 263        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 264        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 265    }
 266
 267    #[inline] // if the range is constant, this helps LLVM to do the
 268    // calculations at compile-time.
 269    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 270    where
 271        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 273    {
 274        let low = *low_b.borrow();
 275        let high = *high_b.borrow();
 276        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 277        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 278    }
 279
 280    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 281        MultiBufferOffset(self.sampler.sample(rng))
 282    }
 283}
 284impl MultiBufferDimension for MultiBufferOffset {
 285    type TextDimension = usize;
 286    fn from_summary(summary: &MBTextSummary) -> Self {
 287        summary.len
 288    }
 289
 290    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 291        self.0 += *other;
 292    }
 293
 294    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 295        *self += summary.len;
 296    }
 297}
 298impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 299    type TextDimension = OffsetUtf16;
 300    fn from_summary(summary: &MBTextSummary) -> Self {
 301        MultiBufferOffsetUtf16(summary.len_utf16)
 302    }
 303
 304    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 305        self.0 += *other;
 306    }
 307
 308    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 309        self.0 += summary.len_utf16;
 310    }
 311}
 312
 313#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 314pub struct BufferOffset(pub usize);
 315
 316impl TextDimension for BufferOffset {
 317    fn from_text_summary(summary: &TextSummary) -> Self {
 318        BufferOffset(usize::from_text_summary(summary))
 319    }
 320    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 321        BufferOffset(usize::from_chunk(chunk))
 322    }
 323    fn add_assign(&mut self, other: &Self) {
 324        TextDimension::add_assign(&mut self.0, &other.0);
 325    }
 326}
 327impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 328    fn zero(cx: ()) -> Self {
 329        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 330    }
 331
 332    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 333        usize::add_summary(&mut self.0, summary, cx);
 334    }
 335}
 336
 337impl Sub for BufferOffset {
 338    type Output = usize;
 339
 340    fn sub(self, other: BufferOffset) -> Self::Output {
 341        self.0 - other.0
 342    }
 343}
 344
 345impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 346    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 347        self.0 += other.key;
 348    }
 349}
 350
 351impl language::ToPoint for BufferOffset {
 352    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 353        self.0.to_point(snapshot)
 354    }
 355}
 356
 357impl language::ToPointUtf16 for BufferOffset {
 358    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 359        self.0.to_point_utf16(snapshot)
 360    }
 361}
 362
 363impl language::ToOffset for BufferOffset {
 364    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 365        self.0.to_offset(snapshot)
 366    }
 367}
 368
 369impl language::ToOffsetUtf16 for BufferOffset {
 370    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 371        self.0.to_offset_utf16(snapshot)
 372    }
 373}
 374
 375#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 376pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 377
 378impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 379    type Output = MultiBufferOffsetUtf16;
 380
 381    fn add(self, rhs: usize) -> Self::Output {
 382        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 383    }
 384}
 385
 386impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 387    type Output = Self;
 388
 389    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 390        MultiBufferOffsetUtf16(self.0 + rhs)
 391    }
 392}
 393
 394impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 395    fn add_assign(&mut self, rhs: OffsetUtf16) {
 396        self.0 += rhs;
 397    }
 398}
 399
 400impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 401    fn add_assign(&mut self, rhs: usize) {
 402        self.0.0 += rhs;
 403    }
 404}
 405
 406impl Sub for MultiBufferOffsetUtf16 {
 407    type Output = OffsetUtf16;
 408
 409    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 410        self.0 - other.0
 411    }
 412}
 413
 414impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 415    type Output = MultiBufferOffsetUtf16;
 416
 417    fn sub(self, other: OffsetUtf16) -> Self::Output {
 418        MultiBufferOffsetUtf16(self.0 - other)
 419    }
 420}
 421
 422#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 423pub struct BufferOffsetUtf16(pub OffsetUtf16);
 424
 425impl MultiBufferOffset {
 426    const ZERO: Self = Self(0);
 427    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 428        self.0.saturating_sub(other.0)
 429    }
 430    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 431        MultiBufferOffset(self.0.saturating_sub(other))
 432    }
 433}
 434
 435impl ops::Sub for MultiBufferOffset {
 436    type Output = usize;
 437
 438    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 439        self.0 - other.0
 440    }
 441}
 442
 443impl ops::Sub<usize> for MultiBufferOffset {
 444    type Output = Self;
 445
 446    fn sub(self, other: usize) -> Self::Output {
 447        MultiBufferOffset(self.0 - other)
 448    }
 449}
 450
 451impl ops::SubAssign<usize> for MultiBufferOffset {
 452    fn sub_assign(&mut self, other: usize) {
 453        self.0 -= other;
 454    }
 455}
 456
 457impl ops::Add<usize> for BufferOffset {
 458    type Output = Self;
 459
 460    fn add(self, rhs: usize) -> Self::Output {
 461        BufferOffset(self.0 + rhs)
 462    }
 463}
 464
 465impl ops::AddAssign<usize> for BufferOffset {
 466    fn add_assign(&mut self, other: usize) {
 467        self.0 += other;
 468    }
 469}
 470
 471impl ops::Add<usize> for MultiBufferOffset {
 472    type Output = Self;
 473
 474    fn add(self, rhs: usize) -> Self::Output {
 475        MultiBufferOffset(self.0 + rhs)
 476    }
 477}
 478
 479impl ops::AddAssign<usize> for MultiBufferOffset {
 480    fn add_assign(&mut self, other: usize) {
 481        self.0 += other;
 482    }
 483}
 484
 485impl ops::Add<isize> for MultiBufferOffset {
 486    type Output = Self;
 487
 488    fn add(self, rhs: isize) -> Self::Output {
 489        MultiBufferOffset((self.0 as isize + rhs) as usize)
 490    }
 491}
 492
 493impl ops::Add for MultiBufferOffset {
 494    type Output = Self;
 495
 496    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 497        MultiBufferOffset(self.0 + rhs.0)
 498    }
 499}
 500
 501impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 502    fn add_assign(&mut self, other: MultiBufferOffset) {
 503        self.0 += other.0;
 504    }
 505}
 506
 507pub trait ToOffset: 'static + fmt::Debug {
 508    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 509    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 510}
 511
 512pub trait ToPoint: 'static + fmt::Debug {
 513    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 514    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 515}
 516
 517struct BufferState {
 518    buffer: Entity<Buffer>,
 519    last_version: RefCell<clock::Global>,
 520    last_non_text_state_update_count: Cell<usize>,
 521    excerpts: Vec<Locator>,
 522    _subscriptions: [gpui::Subscription; 2],
 523}
 524
 525struct DiffState {
 526    diff: Entity<BufferDiff>,
 527    is_inverted: bool,
 528    _subscription: gpui::Subscription,
 529}
 530
 531impl DiffState {
 532    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 533        DiffStateSnapshot {
 534            diff: self.diff.read(cx).snapshot(cx),
 535            is_inverted: self.is_inverted,
 536        }
 537    }
 538}
 539
 540#[derive(Clone)]
 541struct DiffStateSnapshot {
 542    diff: BufferDiffSnapshot,
 543    is_inverted: bool,
 544}
 545
 546impl std::ops::Deref for DiffStateSnapshot {
 547    type Target = BufferDiffSnapshot;
 548
 549    fn deref(&self) -> &Self::Target {
 550        &self.diff
 551    }
 552}
 553
 554impl DiffState {
 555    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 556        DiffState {
 557            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 558                BufferDiffEvent::DiffChanged(DiffChanged {
 559                    changed_range,
 560                    base_text_changed_range: _,
 561                    extended_range,
 562                }) => {
 563                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 564                    let range = if use_extended {
 565                        extended_range.clone()
 566                    } else {
 567                        changed_range.clone()
 568                    };
 569                    if let Some(range) = range {
 570                        this.buffer_diff_changed(diff, range, cx)
 571                    }
 572                    cx.emit(Event::BufferDiffChanged);
 573                }
 574                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 575                _ => {}
 576            }),
 577            diff,
 578            is_inverted: false,
 579        }
 580    }
 581
 582    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 583        DiffState {
 584            _subscription: cx.subscribe(&diff, {
 585                move |this, diff, event, cx| match event {
 586                    BufferDiffEvent::DiffChanged(DiffChanged {
 587                        changed_range: _,
 588                        base_text_changed_range,
 589                        extended_range: _,
 590                    }) => {
 591                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 592                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 593                        }
 594                        cx.emit(Event::BufferDiffChanged);
 595                    }
 596                    BufferDiffEvent::LanguageChanged => {
 597                        this.inverted_buffer_diff_language_changed(diff, cx)
 598                    }
 599                    _ => {}
 600                }
 601            }),
 602            diff,
 603            is_inverted: true,
 604        }
 605    }
 606}
 607
 608/// The contents of a [`MultiBuffer`] at a single point in time.
 609#[derive(Clone, Default)]
 610pub struct MultiBufferSnapshot {
 611    excerpts: SumTree<Excerpt>,
 612    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 613    diff_transforms: SumTree<DiffTransform>,
 614    non_text_state_update_count: usize,
 615    edit_count: usize,
 616    is_dirty: bool,
 617    has_deleted_file: bool,
 618    has_conflict: bool,
 619    has_inverted_diff: bool,
 620    /// immutable fields
 621    singleton: bool,
 622    excerpt_ids: SumTree<ExcerptIdMapping>,
 623    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 624    trailing_excerpt_update_count: usize,
 625    all_diff_hunks_expanded: bool,
 626    show_deleted_hunks: bool,
 627    use_extended_diff_range: bool,
 628    show_headers: bool,
 629}
 630
 631// follower: None
 632// - BufferContent(Some)
 633// - BufferContent(None)
 634// - DeletedHunk
 635//
 636// follower: Some
 637// - BufferContent(Some)
 638// - BufferContent(None)
 639
 640#[derive(Debug, Clone)]
 641enum DiffTransform {
 642    // RealText
 643    BufferContent {
 644        summary: MBTextSummary,
 645        // modified_hunk_info
 646        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 647    },
 648    // ExpandedHunkText
 649    DeletedHunk {
 650        summary: TextSummary,
 651        buffer_id: BufferId,
 652        hunk_info: DiffTransformHunkInfo,
 653        base_text_byte_range: Range<usize>,
 654        has_trailing_newline: bool,
 655    },
 656}
 657
 658#[derive(Clone, Copy, Debug)]
 659struct DiffTransformHunkInfo {
 660    excerpt_id: ExcerptId,
 661    hunk_start_anchor: text::Anchor,
 662    hunk_secondary_status: DiffHunkSecondaryStatus,
 663    is_logically_deleted: bool,
 664}
 665
 666impl Eq for DiffTransformHunkInfo {}
 667
 668impl PartialEq for DiffTransformHunkInfo {
 669    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 670        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 671    }
 672}
 673
 674impl std::hash::Hash for DiffTransformHunkInfo {
 675    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 676        self.excerpt_id.hash(state);
 677        self.hunk_start_anchor.hash(state);
 678    }
 679}
 680
 681#[derive(Clone)]
 682pub struct ExcerptInfo {
 683    pub id: ExcerptId,
 684    pub buffer: BufferSnapshot,
 685    pub buffer_id: BufferId,
 686    pub range: ExcerptRange<text::Anchor>,
 687    pub end_row: MultiBufferRow,
 688}
 689
 690impl std::fmt::Debug for ExcerptInfo {
 691    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 692        f.debug_struct(type_name::<Self>())
 693            .field("id", &self.id)
 694            .field("buffer_id", &self.buffer_id)
 695            .field("path", &self.buffer.file().map(|f| f.path()))
 696            .field("range", &self.range)
 697            .finish()
 698    }
 699}
 700
 701/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 702#[derive(Debug)]
 703pub struct ExcerptBoundary {
 704    pub prev: Option<ExcerptInfo>,
 705    pub next: ExcerptInfo,
 706    /// The row in the `MultiBuffer` where the boundary is located
 707    pub row: MultiBufferRow,
 708}
 709
 710impl ExcerptBoundary {
 711    pub fn starts_new_buffer(&self) -> bool {
 712        match (self.prev.as_ref(), &self.next) {
 713            (None, _) => true,
 714            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 715        }
 716    }
 717}
 718
 719#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 720pub struct ExpandInfo {
 721    pub direction: ExpandExcerptDirection,
 722    pub excerpt_id: ExcerptId,
 723}
 724
 725#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 726pub struct RowInfo {
 727    pub buffer_id: Option<BufferId>,
 728    pub buffer_row: Option<u32>,
 729    pub multibuffer_row: Option<MultiBufferRow>,
 730    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 731    pub expand_info: Option<ExpandInfo>,
 732    pub wrapped_buffer_row: Option<u32>,
 733}
 734
 735/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 736#[derive(Clone)]
 737struct Excerpt {
 738    /// The unique identifier for this excerpt
 739    id: ExcerptId,
 740    /// The location of the excerpt in the [`MultiBuffer`]
 741    locator: Locator,
 742    /// The buffer being excerpted
 743    buffer_id: BufferId,
 744    /// A snapshot of the buffer being excerpted
 745    buffer: BufferSnapshot,
 746    /// The range of the buffer to be shown in the excerpt
 747    range: ExcerptRange<text::Anchor>,
 748    /// The last row in the excerpted slice of the buffer
 749    max_buffer_row: BufferRow,
 750    /// A summary of the text in the excerpt
 751    text_summary: TextSummary,
 752    has_trailing_newline: bool,
 753}
 754
 755/// A public view into an `Excerpt` in a [`MultiBuffer`].
 756///
 757/// Contains methods for getting the [`Buffer`] of the excerpt,
 758/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 759#[derive(Clone)]
 760pub struct MultiBufferExcerpt<'a> {
 761    excerpt: &'a Excerpt,
 762    diff_transforms:
 763        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 764    /// The offset in the multibuffer considering diff transforms.
 765    offset: MultiBufferOffset,
 766    /// The offset in the multibuffer without diff transforms.
 767    excerpt_offset: ExcerptOffset,
 768    buffer_offset: BufferOffset,
 769}
 770
 771#[derive(Clone, Debug)]
 772struct ExcerptIdMapping {
 773    id: ExcerptId,
 774    locator: Locator,
 775}
 776
 777/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 778/// These ranges are relative to the buffer itself
 779#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 780pub struct ExcerptRange<T> {
 781    /// The full range of text to be shown in the excerpt.
 782    pub context: Range<T>,
 783    /// The primary range of text to be highlighted in the excerpt.
 784    /// In a multi-buffer search, this would be the text that matched the search
 785    pub primary: Range<T>,
 786}
 787
 788impl<T: Clone> ExcerptRange<T> {
 789    pub fn new(context: Range<T>) -> Self {
 790        Self {
 791            context: context.clone(),
 792            primary: context,
 793        }
 794    }
 795}
 796
 797#[derive(Clone, Debug, Default)]
 798pub struct ExcerptSummary {
 799    excerpt_id: ExcerptId,
 800    /// The location of the last [`Excerpt`] being summarized
 801    excerpt_locator: Locator,
 802    widest_line_number: u32,
 803    text: MBTextSummary,
 804}
 805
 806#[derive(Debug, Clone)]
 807pub struct DiffTransformSummary {
 808    input: MBTextSummary,
 809    output: MBTextSummary,
 810}
 811
 812/// Summary of a string of text.
 813#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 814pub struct MBTextSummary {
 815    /// Length in bytes.
 816    pub len: MultiBufferOffset,
 817    /// Length in UTF-8.
 818    pub chars: usize,
 819    /// Length in UTF-16 code units
 820    pub len_utf16: OffsetUtf16,
 821    /// A point representing the number of lines and the length of the last line.
 822    ///
 823    /// In other words, it marks the point after the last byte in the text, (if
 824    /// EOF was a character, this would be its position).
 825    pub lines: Point,
 826    /// How many `char`s are in the first line
 827    pub first_line_chars: u32,
 828    /// How many `char`s are in the last line
 829    pub last_line_chars: u32,
 830    /// How many UTF-16 code units are in the last line
 831    pub last_line_len_utf16: u32,
 832    /// The row idx of the longest row
 833    pub longest_row: u32,
 834    /// How many `char`s are in the longest row
 835    pub longest_row_chars: u32,
 836}
 837
 838impl From<TextSummary> for MBTextSummary {
 839    fn from(summary: TextSummary) -> Self {
 840        MBTextSummary {
 841            len: MultiBufferOffset(summary.len),
 842            chars: summary.chars,
 843            len_utf16: summary.len_utf16,
 844            lines: summary.lines,
 845            first_line_chars: summary.first_line_chars,
 846            last_line_chars: summary.last_line_chars,
 847            last_line_len_utf16: summary.last_line_len_utf16,
 848            longest_row: summary.longest_row,
 849            longest_row_chars: summary.longest_row_chars,
 850        }
 851    }
 852}
 853
 854impl From<MBTextSummary> for TextSummary {
 855    fn from(summary: MBTextSummary) -> Self {
 856        TextSummary {
 857            len: summary.len.0,
 858            chars: summary.chars,
 859            len_utf16: summary.len_utf16,
 860            lines: summary.lines,
 861            first_line_chars: summary.first_line_chars,
 862            last_line_chars: summary.last_line_chars,
 863            last_line_len_utf16: summary.last_line_len_utf16,
 864            longest_row: summary.longest_row,
 865            longest_row_chars: summary.longest_row_chars,
 866        }
 867    }
 868}
 869
 870impl From<&str> for MBTextSummary {
 871    fn from(text: &str) -> Self {
 872        MBTextSummary::from(TextSummary::from(text))
 873    }
 874}
 875
 876impl MultiBufferDimension for MBTextSummary {
 877    type TextDimension = TextSummary;
 878
 879    fn from_summary(summary: &MBTextSummary) -> Self {
 880        *summary
 881    }
 882
 883    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 884        *self += *summary;
 885    }
 886
 887    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 888        *self += *summary;
 889    }
 890}
 891
 892impl AddAssign for MBTextSummary {
 893    fn add_assign(&mut self, other: MBTextSummary) {
 894        let joined_chars = self.last_line_chars + other.first_line_chars;
 895        if joined_chars > self.longest_row_chars {
 896            self.longest_row = self.lines.row;
 897            self.longest_row_chars = joined_chars;
 898        }
 899        if other.longest_row_chars > self.longest_row_chars {
 900            self.longest_row = self.lines.row + other.longest_row;
 901            self.longest_row_chars = other.longest_row_chars;
 902        }
 903
 904        if self.lines.row == 0 {
 905            self.first_line_chars += other.first_line_chars;
 906        }
 907
 908        if other.lines.row == 0 {
 909            self.last_line_chars += other.first_line_chars;
 910            self.last_line_len_utf16 += other.last_line_len_utf16;
 911        } else {
 912            self.last_line_chars = other.last_line_chars;
 913            self.last_line_len_utf16 = other.last_line_len_utf16;
 914        }
 915
 916        self.chars += other.chars;
 917        self.len += other.len;
 918        self.len_utf16 += other.len_utf16;
 919        self.lines += other.lines;
 920    }
 921}
 922
 923impl AddAssign<TextSummary> for MBTextSummary {
 924    fn add_assign(&mut self, other: TextSummary) {
 925        *self += MBTextSummary::from(other);
 926    }
 927}
 928
 929impl MBTextSummary {
 930    pub fn lines_utf16(&self) -> PointUtf16 {
 931        PointUtf16 {
 932            row: self.lines.row,
 933            column: self.last_line_len_utf16,
 934        }
 935    }
 936}
 937
 938impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 939where
 940    K: MultiBufferDimension,
 941    V: MultiBufferDimension,
 942{
 943    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 944
 945    fn from_summary(summary: &MBTextSummary) -> Self {
 946        Self {
 947            key: K::from_summary(summary),
 948            value: Some(V::from_summary(summary)),
 949        }
 950    }
 951
 952    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 953        self.key.add_text_dim(&summary.key);
 954        if let Some(value) = &mut self.value {
 955            if let Some(other_value) = summary.value.as_ref() {
 956                value.add_text_dim(other_value);
 957            }
 958        }
 959    }
 960
 961    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 962        self.key.add_mb_text_summary(summary);
 963        if let Some(value) = &mut self.value {
 964            value.add_mb_text_summary(summary);
 965        }
 966    }
 967}
 968
 969#[derive(Clone)]
 970pub struct MultiBufferRows<'a> {
 971    point: Point,
 972    is_empty: bool,
 973    is_singleton: bool,
 974    cursor: MultiBufferCursor<'a, Point, Point>,
 975}
 976
 977pub struct MultiBufferChunks<'a> {
 978    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 979    diff_transforms:
 980        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 981    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 982    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 983    buffer_chunk: Option<Chunk<'a>>,
 984    range: Range<MultiBufferOffset>,
 985    excerpt_offset_range: Range<ExcerptOffset>,
 986    excerpt_chunks: Option<ExcerptChunks<'a>>,
 987    language_aware: bool,
 988}
 989
 990pub struct ReversedMultiBufferChunks<'a> {
 991    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 992    current_chunks: Option<rope::Chunks<'a>>,
 993    start: MultiBufferOffset,
 994    offset: MultiBufferOffset,
 995}
 996
 997pub struct MultiBufferBytes<'a> {
 998    range: Range<MultiBufferOffset>,
 999    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1000    excerpt_bytes: Option<text::Bytes<'a>>,
1001    has_trailing_newline: bool,
1002    chunk: &'a [u8],
1003}
1004
1005pub struct ReversedMultiBufferBytes<'a> {
1006    range: Range<MultiBufferOffset>,
1007    chunks: ReversedMultiBufferChunks<'a>,
1008    chunk: &'a [u8],
1009}
1010
1011#[derive(Clone)]
1012struct DiffTransforms<MBD> {
1013    output_dimension: OutputDimension<MBD>,
1014    excerpt_dimension: ExcerptDimension<MBD>,
1015}
1016
1017impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1018    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1019        Self {
1020            output_dimension: OutputDimension::zero(cx),
1021            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1022                cx,
1023            ),
1024        }
1025    }
1026
1027    fn add_summary(
1028        &mut self,
1029        summary: &'a DiffTransformSummary,
1030        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1031    ) {
1032        self.output_dimension.add_summary(summary, cx);
1033        self.excerpt_dimension.add_summary(summary, cx);
1034    }
1035}
1036
1037#[derive(Clone)]
1038struct MultiBufferCursor<'a, MBD, BD> {
1039    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1040    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1041    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1042    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1043}
1044
1045#[derive(Clone)]
1046struct MultiBufferRegion<'a, MBD, BD> {
1047    buffer: &'a BufferSnapshot,
1048    is_main_buffer: bool,
1049    diff_hunk_status: Option<DiffHunkStatus>,
1050    excerpt: &'a Excerpt,
1051    buffer_range: Range<BD>,
1052    range: Range<MBD>,
1053    has_trailing_newline: bool,
1054}
1055
1056struct ExcerptChunks<'a> {
1057    excerpt_id: ExcerptId,
1058    content_chunks: BufferChunks<'a>,
1059    has_footer: bool,
1060}
1061
1062#[derive(Debug)]
1063struct BufferEdit {
1064    range: Range<BufferOffset>,
1065    new_text: Arc<str>,
1066    is_insertion: bool,
1067    original_indent_column: Option<u32>,
1068    excerpt_id: ExcerptId,
1069}
1070
1071#[derive(Clone, Copy, Debug, PartialEq)]
1072enum DiffChangeKind {
1073    BufferEdited,
1074    DiffUpdated { base_changed: bool },
1075    ExpandOrCollapseHunks { expand: bool },
1076}
1077
1078#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1079pub enum ExpandExcerptDirection {
1080    Up,
1081    Down,
1082    UpAndDown,
1083}
1084
1085impl ExpandExcerptDirection {
1086    pub fn should_expand_up(&self) -> bool {
1087        match self {
1088            ExpandExcerptDirection::Up => true,
1089            ExpandExcerptDirection::Down => false,
1090            ExpandExcerptDirection::UpAndDown => true,
1091        }
1092    }
1093
1094    pub fn should_expand_down(&self) -> bool {
1095        match self {
1096            ExpandExcerptDirection::Up => false,
1097            ExpandExcerptDirection::Down => true,
1098            ExpandExcerptDirection::UpAndDown => true,
1099        }
1100    }
1101}
1102
1103#[derive(Clone, Debug, PartialEq)]
1104pub struct IndentGuide {
1105    pub buffer_id: BufferId,
1106    pub start_row: MultiBufferRow,
1107    pub end_row: MultiBufferRow,
1108    pub depth: u32,
1109    pub tab_size: u32,
1110    pub settings: IndentGuideSettings,
1111}
1112
1113impl IndentGuide {
1114    pub fn indent_level(&self) -> u32 {
1115        self.depth * self.tab_size
1116    }
1117}
1118
1119impl MultiBuffer {
1120    pub fn new(capability: Capability) -> Self {
1121        Self::new_(
1122            capability,
1123            MultiBufferSnapshot {
1124                show_headers: true,
1125                show_deleted_hunks: true,
1126                ..MultiBufferSnapshot::default()
1127            },
1128        )
1129    }
1130
1131    pub fn without_headers(capability: Capability) -> Self {
1132        Self::new_(
1133            capability,
1134            MultiBufferSnapshot {
1135                show_deleted_hunks: true,
1136                ..MultiBufferSnapshot::default()
1137            },
1138        )
1139    }
1140
1141    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1142        let mut this = Self::new_(
1143            buffer.read(cx).capability(),
1144            MultiBufferSnapshot {
1145                singleton: true,
1146                show_deleted_hunks: true,
1147                ..MultiBufferSnapshot::default()
1148            },
1149        );
1150        this.singleton = true;
1151        let buffer_id = buffer.read(cx).remote_id();
1152        this.push_excerpts(
1153            buffer,
1154            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1155                buffer_id,
1156            ))],
1157            cx,
1158        );
1159        this
1160    }
1161
1162    #[inline]
1163    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1164        Self {
1165            snapshot: RefCell::new(snapshot),
1166            buffers: Default::default(),
1167            diffs: HashMap::default(),
1168            subscriptions: Topic::default(),
1169            singleton: false,
1170            capability,
1171            title: None,
1172            excerpts_by_path: Default::default(),
1173            paths_by_excerpt: Default::default(),
1174            buffer_changed_since_sync: Default::default(),
1175            history: History::default(),
1176        }
1177    }
1178
1179    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1180        let mut buffers = BTreeMap::default();
1181        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1182        for (buffer_id, buffer_state) in self.buffers.iter() {
1183            buffer_state.buffer.update(new_cx, |buffer, _| {
1184                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1185            });
1186            buffers.insert(
1187                *buffer_id,
1188                BufferState {
1189                    buffer: buffer_state.buffer.clone(),
1190                    last_version: buffer_state.last_version.clone(),
1191                    last_non_text_state_update_count: buffer_state
1192                        .last_non_text_state_update_count
1193                        .clone(),
1194                    excerpts: buffer_state.excerpts.clone(),
1195                    _subscriptions: [
1196                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1197                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1198                    ],
1199                },
1200            );
1201        }
1202        let mut diff_bases = HashMap::default();
1203        for (buffer_id, diff) in self.diffs.iter() {
1204            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1205        }
1206        Self {
1207            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1208            buffers: buffers,
1209            excerpts_by_path: Default::default(),
1210            paths_by_excerpt: Default::default(),
1211            diffs: diff_bases,
1212            subscriptions: Default::default(),
1213            singleton: self.singleton,
1214            capability: self.capability,
1215            history: self.history.clone(),
1216            title: self.title.clone(),
1217            buffer_changed_since_sync,
1218        }
1219    }
1220
1221    pub fn set_group_interval(&mut self, group_interval: Duration) {
1222        self.history.set_group_interval(group_interval);
1223    }
1224
1225    pub fn with_title(mut self, title: String) -> Self {
1226        self.title = Some(title);
1227        self
1228    }
1229
1230    pub fn read_only(&self) -> bool {
1231        !self.capability.editable()
1232    }
1233
1234    pub fn capability(&self) -> Capability {
1235        self.capability
1236    }
1237
1238    /// Returns an up-to-date snapshot of the MultiBuffer.
1239    #[ztracing::instrument(skip_all)]
1240    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1241        self.sync(cx);
1242        self.snapshot.borrow().clone()
1243    }
1244
1245    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1246        self.sync(cx);
1247        self.snapshot.borrow()
1248    }
1249
1250    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1251        if self.singleton {
1252            Some(self.buffers.values().next().unwrap().buffer.clone())
1253        } else {
1254            None
1255        }
1256    }
1257
1258    pub fn is_singleton(&self) -> bool {
1259        self.singleton
1260    }
1261
1262    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1263        self.subscriptions.subscribe()
1264    }
1265
1266    pub fn is_dirty(&self, cx: &App) -> bool {
1267        self.read(cx).is_dirty()
1268    }
1269
1270    pub fn has_deleted_file(&self, cx: &App) -> bool {
1271        self.read(cx).has_deleted_file()
1272    }
1273
1274    pub fn has_conflict(&self, cx: &App) -> bool {
1275        self.read(cx).has_conflict()
1276    }
1277
1278    // The `is_empty` signature doesn't match what clippy expects
1279    #[allow(clippy::len_without_is_empty)]
1280    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1281        self.read(cx).len()
1282    }
1283
1284    pub fn is_empty(&self) -> bool {
1285        self.buffers.is_empty()
1286    }
1287
1288    pub fn edit<I, S, T>(
1289        &mut self,
1290        edits: I,
1291        autoindent_mode: Option<AutoindentMode>,
1292        cx: &mut Context<Self>,
1293    ) where
1294        I: IntoIterator<Item = (Range<S>, T)>,
1295        S: ToOffset,
1296        T: Into<Arc<str>>,
1297    {
1298        self.edit_internal(edits, autoindent_mode, true, cx);
1299    }
1300
1301    pub fn edit_non_coalesce<I, S, T>(
1302        &mut self,
1303        edits: I,
1304        autoindent_mode: Option<AutoindentMode>,
1305        cx: &mut Context<Self>,
1306    ) where
1307        I: IntoIterator<Item = (Range<S>, T)>,
1308        S: ToOffset,
1309        T: Into<Arc<str>>,
1310    {
1311        self.edit_internal(edits, autoindent_mode, false, cx);
1312    }
1313
1314    fn edit_internal<I, S, T>(
1315        &mut self,
1316        edits: I,
1317        autoindent_mode: Option<AutoindentMode>,
1318        coalesce_adjacent: bool,
1319        cx: &mut Context<Self>,
1320    ) where
1321        I: IntoIterator<Item = (Range<S>, T)>,
1322        S: ToOffset,
1323        T: Into<Arc<str>>,
1324    {
1325        if self.read_only() || self.buffers.is_empty() {
1326            return;
1327        }
1328        self.sync_mut(cx);
1329        let edits = edits
1330            .into_iter()
1331            .map(|(range, new_text)| {
1332                let mut range = range.start.to_offset(self.snapshot.get_mut())
1333                    ..range.end.to_offset(self.snapshot.get_mut());
1334                if range.start > range.end {
1335                    mem::swap(&mut range.start, &mut range.end);
1336                }
1337                (range, new_text.into())
1338            })
1339            .collect::<Vec<_>>();
1340
1341        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1342
1343        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1344        fn edit_internal(
1345            this: &mut MultiBuffer,
1346            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1347            mut autoindent_mode: Option<AutoindentMode>,
1348            coalesce_adjacent: bool,
1349            cx: &mut Context<MultiBuffer>,
1350        ) {
1351            let original_indent_columns = match &mut autoindent_mode {
1352                Some(AutoindentMode::Block {
1353                    original_indent_columns,
1354                }) => mem::take(original_indent_columns),
1355                _ => Default::default(),
1356            };
1357
1358            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1359                edits,
1360                this.snapshot.get_mut(),
1361                &original_indent_columns,
1362            );
1363
1364            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1365            for (buffer_id, mut edits) in buffer_edits {
1366                buffer_ids.push(buffer_id);
1367                edits.sort_by_key(|edit| edit.range.start);
1368                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1369                    let mut edits = edits.into_iter().peekable();
1370                    let mut insertions = Vec::new();
1371                    let mut original_indent_columns = Vec::new();
1372                    let mut deletions = Vec::new();
1373                    let empty_str: Arc<str> = Arc::default();
1374                    while let Some(BufferEdit {
1375                        mut range,
1376                        mut new_text,
1377                        mut is_insertion,
1378                        original_indent_column,
1379                        excerpt_id,
1380                    }) = edits.next()
1381                    {
1382                        while let Some(BufferEdit {
1383                            range: next_range,
1384                            is_insertion: next_is_insertion,
1385                            new_text: next_new_text,
1386                            excerpt_id: next_excerpt_id,
1387                            ..
1388                        }) = edits.peek()
1389                        {
1390                            let should_coalesce = if coalesce_adjacent {
1391                                range.end >= next_range.start
1392                            } else {
1393                                range.end > next_range.start
1394                            };
1395
1396                            if should_coalesce {
1397                                range.end = cmp::max(next_range.end, range.end);
1398                                is_insertion |= *next_is_insertion;
1399                                if excerpt_id == *next_excerpt_id {
1400                                    new_text = format!("{new_text}{next_new_text}").into();
1401                                }
1402                                edits.next();
1403                            } else {
1404                                break;
1405                            }
1406                        }
1407
1408                        if is_insertion {
1409                            original_indent_columns.push(original_indent_column);
1410                            insertions.push((
1411                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1412                                new_text.clone(),
1413                            ));
1414                        } else if !range.is_empty() {
1415                            deletions.push((
1416                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1417                                empty_str.clone(),
1418                            ));
1419                        }
1420                    }
1421
1422                    let deletion_autoindent_mode =
1423                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1424                            Some(AutoindentMode::Block {
1425                                original_indent_columns: Default::default(),
1426                            })
1427                        } else {
1428                            autoindent_mode.clone()
1429                        };
1430                    let insertion_autoindent_mode =
1431                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1432                            Some(AutoindentMode::Block {
1433                                original_indent_columns,
1434                            })
1435                        } else {
1436                            autoindent_mode.clone()
1437                        };
1438
1439                    if coalesce_adjacent {
1440                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1441                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1442                    } else {
1443                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1444                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1445                    }
1446                })
1447            }
1448
1449            cx.emit(Event::ExcerptsEdited {
1450                excerpt_ids: edited_excerpt_ids,
1451                buffer_ids,
1452            });
1453        }
1454    }
1455
1456    fn convert_edits_to_buffer_edits(
1457        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1458        snapshot: &MultiBufferSnapshot,
1459        original_indent_columns: &[Option<u32>],
1460    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1461        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1462        let mut edited_excerpt_ids = Vec::new();
1463        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1464        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1465            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1466
1467            cursor.seek(&range.start);
1468            let mut start_region = cursor.region().expect("start offset out of bounds");
1469            if !start_region.is_main_buffer {
1470                cursor.next();
1471                if let Some(region) = cursor.region() {
1472                    start_region = region;
1473                } else {
1474                    continue;
1475                }
1476            }
1477
1478            if range.end < start_region.range.start {
1479                continue;
1480            }
1481
1482            let start_region = start_region.clone();
1483            if range.end > start_region.range.end {
1484                cursor.seek_forward(&range.end);
1485            }
1486            let mut end_region = cursor.region().expect("end offset out of bounds");
1487            if !end_region.is_main_buffer {
1488                cursor.prev();
1489                if let Some(region) = cursor.region() {
1490                    end_region = region;
1491                } else {
1492                    continue;
1493                }
1494            }
1495
1496            if range.start > end_region.range.end {
1497                continue;
1498            }
1499
1500            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1501            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1502            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1503                .min(start_region.buffer_range.end);
1504            let buffer_end =
1505                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1506
1507            if start_region.excerpt.id == end_region.excerpt.id {
1508                if start_region.buffer.capability == Capability::ReadWrite
1509                    && start_region.is_main_buffer
1510                {
1511                    edited_excerpt_ids.push(start_region.excerpt.id);
1512                    buffer_edits
1513                        .entry(start_region.buffer.remote_id())
1514                        .or_default()
1515                        .push(BufferEdit {
1516                            range: buffer_start..buffer_end,
1517                            new_text,
1518                            is_insertion: true,
1519                            original_indent_column,
1520                            excerpt_id: start_region.excerpt.id,
1521                        });
1522                }
1523            } else {
1524                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1525                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1526                if start_region.buffer.capability == Capability::ReadWrite
1527                    && start_region.is_main_buffer
1528                {
1529                    edited_excerpt_ids.push(start_region.excerpt.id);
1530                    buffer_edits
1531                        .entry(start_region.buffer.remote_id())
1532                        .or_default()
1533                        .push(BufferEdit {
1534                            range: start_excerpt_range,
1535                            new_text: new_text.clone(),
1536                            is_insertion: true,
1537                            original_indent_column,
1538                            excerpt_id: start_region.excerpt.id,
1539                        });
1540                }
1541                let excerpt_id = end_region.excerpt.id;
1542                if end_region.buffer.capability == Capability::ReadWrite
1543                    && end_region.is_main_buffer
1544                {
1545                    edited_excerpt_ids.push(excerpt_id);
1546                    buffer_edits
1547                        .entry(end_region.buffer.remote_id())
1548                        .or_default()
1549                        .push(BufferEdit {
1550                            range: end_excerpt_range,
1551                            new_text: new_text.clone(),
1552                            is_insertion: false,
1553                            original_indent_column,
1554                            excerpt_id,
1555                        });
1556                }
1557
1558                cursor.seek(&range.start);
1559                cursor.next_excerpt();
1560                while let Some(region) = cursor.region() {
1561                    if region.excerpt.id == excerpt_id {
1562                        break;
1563                    }
1564                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1565                        edited_excerpt_ids.push(region.excerpt.id);
1566                        buffer_edits
1567                            .entry(region.buffer.remote_id())
1568                            .or_default()
1569                            .push(BufferEdit {
1570                                range: region.buffer_range.clone(),
1571                                new_text: new_text.clone(),
1572                                is_insertion: false,
1573                                original_indent_column,
1574                                excerpt_id: region.excerpt.id,
1575                            });
1576                    }
1577                    cursor.next_excerpt();
1578                }
1579            }
1580        }
1581        (buffer_edits, edited_excerpt_ids)
1582    }
1583
1584    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1585    where
1586        I: IntoIterator<Item = Range<S>>,
1587        S: ToOffset,
1588    {
1589        if self.read_only() || self.buffers.is_empty() {
1590            return;
1591        }
1592        self.sync_mut(cx);
1593        let empty = Arc::<str>::from("");
1594        let edits = ranges
1595            .into_iter()
1596            .map(|range| {
1597                let mut range = range.start.to_offset(self.snapshot.get_mut())
1598                    ..range.end.to_offset(&self.snapshot.get_mut());
1599                if range.start > range.end {
1600                    mem::swap(&mut range.start, &mut range.end);
1601                }
1602                (range, empty.clone())
1603            })
1604            .collect::<Vec<_>>();
1605
1606        return autoindent_ranges_internal(self, edits, cx);
1607
1608        fn autoindent_ranges_internal(
1609            this: &mut MultiBuffer,
1610            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1611            cx: &mut Context<MultiBuffer>,
1612        ) {
1613            let (buffer_edits, edited_excerpt_ids) =
1614                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1615
1616            let mut buffer_ids = Vec::new();
1617            for (buffer_id, mut edits) in buffer_edits {
1618                buffer_ids.push(buffer_id);
1619                edits.sort_unstable_by_key(|edit| edit.range.start);
1620
1621                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1622                for edit in edits {
1623                    if let Some(last_range) = ranges.last_mut()
1624                        && edit.range.start <= last_range.end
1625                    {
1626                        last_range.end = last_range.end.max(edit.range.end);
1627                        continue;
1628                    }
1629                    ranges.push(edit.range);
1630                }
1631
1632                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1633                    buffer.autoindent_ranges(ranges, cx);
1634                })
1635            }
1636
1637            cx.emit(Event::ExcerptsEdited {
1638                excerpt_ids: edited_excerpt_ids,
1639                buffer_ids,
1640            });
1641        }
1642    }
1643
1644    pub fn set_active_selections(
1645        &self,
1646        selections: &[Selection<Anchor>],
1647        line_mode: bool,
1648        cursor_shape: CursorShape,
1649        cx: &mut Context<Self>,
1650    ) {
1651        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1652            Default::default();
1653        let snapshot = self.read(cx);
1654        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1655        for selection in selections {
1656            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1657            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1658
1659            cursor.seek(&Some(start_locator), Bias::Left);
1660            while let Some(excerpt) = cursor.item()
1661                && excerpt.locator <= *end_locator
1662            {
1663                let mut start = excerpt.range.context.start;
1664                let mut end = excerpt.range.context.end;
1665                if excerpt.id == selection.start.excerpt_id {
1666                    start = selection.start.text_anchor;
1667                }
1668                if excerpt.id == selection.end.excerpt_id {
1669                    end = selection.end.text_anchor;
1670                }
1671                selections_by_buffer
1672                    .entry(excerpt.buffer_id)
1673                    .or_default()
1674                    .push(Selection {
1675                        id: selection.id,
1676                        start,
1677                        end,
1678                        reversed: selection.reversed,
1679                        goal: selection.goal,
1680                    });
1681
1682                cursor.next();
1683            }
1684        }
1685
1686        for (buffer_id, buffer_state) in self.buffers.iter() {
1687            if !selections_by_buffer.contains_key(buffer_id) {
1688                buffer_state
1689                    .buffer
1690                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1691            }
1692        }
1693
1694        for (buffer_id, mut selections) in selections_by_buffer {
1695            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1696                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1697                let mut selections = selections.into_iter().peekable();
1698                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1699                    let mut selection = selections.next()?;
1700                    while let Some(next_selection) = selections.peek() {
1701                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1702                            let next_selection = selections.next().unwrap();
1703                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1704                                selection.end = next_selection.end;
1705                            }
1706                        } else {
1707                            break;
1708                        }
1709                    }
1710                    Some(selection)
1711                }));
1712                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1713            });
1714        }
1715    }
1716
1717    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1718        for buffer in self.buffers.values() {
1719            buffer
1720                .buffer
1721                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1722        }
1723    }
1724
1725    pub fn push_excerpts<O>(
1726        &mut self,
1727        buffer: Entity<Buffer>,
1728        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1729        cx: &mut Context<Self>,
1730    ) -> Vec<ExcerptId>
1731    where
1732        O: text::ToOffset,
1733    {
1734        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1735    }
1736
1737    #[instrument(skip_all)]
1738    fn merge_excerpt_ranges<'a>(
1739        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1740    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1741        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1742        let mut counts: Vec<usize> = Vec::new();
1743        for range in expanded_ranges {
1744            if let Some(last_range) = merged_ranges.last_mut() {
1745                assert!(
1746                    last_range.context.start <= range.context.start,
1747                    "ranges must be sorted: {last_range:?} <= {range:?}"
1748                );
1749                if last_range.context.end >= range.context.start
1750                    || last_range.context.end.row + 1 == range.context.start.row
1751                {
1752                    last_range.context.end = range.context.end.max(last_range.context.end);
1753                    *counts.last_mut().unwrap() += 1;
1754                    continue;
1755                }
1756            }
1757            merged_ranges.push(range.clone());
1758            counts.push(1);
1759        }
1760        (merged_ranges, counts)
1761    }
1762
1763    pub fn insert_excerpts_after<O>(
1764        &mut self,
1765        prev_excerpt_id: ExcerptId,
1766        buffer: Entity<Buffer>,
1767        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1768        cx: &mut Context<Self>,
1769    ) -> Vec<ExcerptId>
1770    where
1771        O: text::ToOffset,
1772    {
1773        let mut ids = Vec::new();
1774        let mut next_excerpt_id =
1775            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1776                last_entry.id.0 + 1
1777            } else {
1778                1
1779            };
1780        self.insert_excerpts_with_ids_after(
1781            prev_excerpt_id,
1782            buffer,
1783            ranges.into_iter().map(|range| {
1784                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1785                ids.push(id);
1786                (id, range)
1787            }),
1788            cx,
1789        );
1790        ids
1791    }
1792
1793    pub fn insert_excerpts_with_ids_after<O>(
1794        &mut self,
1795        prev_excerpt_id: ExcerptId,
1796        buffer: Entity<Buffer>,
1797        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1798        cx: &mut Context<Self>,
1799    ) where
1800        O: text::ToOffset,
1801    {
1802        assert_eq!(self.history.transaction_depth(), 0);
1803        let mut ranges = ranges.into_iter().peekable();
1804        if ranges.peek().is_none() {
1805            return Default::default();
1806        }
1807
1808        self.sync_mut(cx);
1809
1810        let buffer_snapshot = buffer.read(cx).snapshot();
1811        let buffer_id = buffer_snapshot.remote_id();
1812
1813        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1814            self.buffer_changed_since_sync.replace(true);
1815            buffer.update(cx, |buffer, _| {
1816                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1817            });
1818            BufferState {
1819                last_version: RefCell::new(buffer_snapshot.version().clone()),
1820                last_non_text_state_update_count: Cell::new(
1821                    buffer_snapshot.non_text_state_update_count(),
1822                ),
1823                excerpts: Default::default(),
1824                _subscriptions: [
1825                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1826                    cx.subscribe(&buffer, Self::on_buffer_event),
1827                ],
1828                buffer: buffer.clone(),
1829            }
1830        });
1831
1832        let mut snapshot = self.snapshot.get_mut();
1833
1834        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1835        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1836        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1837        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1838        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1839
1840        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1841        new_excerpts.update_last(
1842            |excerpt| {
1843                excerpt.has_trailing_newline = true;
1844            },
1845            (),
1846        );
1847
1848        let next_locator = if let Some(excerpt) = cursor.item() {
1849            excerpt.locator.clone()
1850        } else {
1851            Locator::max()
1852        };
1853
1854        let mut excerpts = Vec::new();
1855        while let Some((id, range)) = ranges.next() {
1856            let locator = Locator::between(&prev_locator, &next_locator);
1857            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1858                buffer_state.excerpts.insert(ix, locator.clone());
1859            }
1860            let range = ExcerptRange {
1861                context: buffer_snapshot.anchor_before(&range.context.start)
1862                    ..buffer_snapshot.anchor_after(&range.context.end),
1863                primary: buffer_snapshot.anchor_before(&range.primary.start)
1864                    ..buffer_snapshot.anchor_after(&range.primary.end),
1865            };
1866            excerpts.push((id, range.clone()));
1867            let excerpt = Excerpt::new(
1868                id,
1869                locator.clone(),
1870                buffer_id,
1871                buffer_snapshot.clone(),
1872                range,
1873                ranges.peek().is_some() || cursor.item().is_some(),
1874            );
1875            new_excerpts.push(excerpt, ());
1876            prev_locator = locator.clone();
1877
1878            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1879                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1880            }
1881            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1882        }
1883
1884        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1885
1886        let suffix = cursor.suffix();
1887        let changed_trailing_excerpt = suffix.is_empty();
1888        new_excerpts.append(suffix, ());
1889        drop(cursor);
1890        snapshot.excerpts = new_excerpts;
1891        snapshot.excerpt_ids = new_excerpt_ids;
1892        if changed_trailing_excerpt {
1893            snapshot.trailing_excerpt_update_count += 1;
1894        }
1895
1896        let edits = Self::sync_diff_transforms(
1897            &mut snapshot,
1898            vec![Edit {
1899                old: edit_start..edit_start,
1900                new: edit_start..edit_end,
1901            }],
1902            DiffChangeKind::BufferEdited,
1903        );
1904        if !edits.is_empty() {
1905            self.subscriptions.publish(edits);
1906        }
1907
1908        cx.emit(Event::Edited {
1909            edited_buffer: None,
1910        });
1911        cx.emit(Event::ExcerptsAdded {
1912            buffer,
1913            predecessor: prev_excerpt_id,
1914            excerpts,
1915        });
1916        cx.notify();
1917    }
1918
1919    pub fn clear(&mut self, cx: &mut Context<Self>) {
1920        self.sync_mut(cx);
1921        let ids = self.excerpt_ids();
1922        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1923        self.excerpts_by_path.clear();
1924        self.paths_by_excerpt.clear();
1925        let MultiBufferSnapshot {
1926            excerpts,
1927            diffs: _,
1928            diff_transforms: _,
1929            non_text_state_update_count: _,
1930            edit_count: _,
1931            is_dirty,
1932            has_deleted_file,
1933            has_conflict,
1934            has_inverted_diff,
1935            singleton: _,
1936            excerpt_ids: _,
1937            replaced_excerpts,
1938            trailing_excerpt_update_count,
1939            all_diff_hunks_expanded: _,
1940            show_deleted_hunks: _,
1941            use_extended_diff_range: _,
1942            show_headers: _,
1943        } = self.snapshot.get_mut();
1944        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1945        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1946        *excerpts = Default::default();
1947        *trailing_excerpt_update_count += 1;
1948        *is_dirty = false;
1949        *has_deleted_file = false;
1950        *has_conflict = false;
1951        *has_inverted_diff = false;
1952        replaced_excerpts.clear();
1953
1954        let edits = Self::sync_diff_transforms(
1955            self.snapshot.get_mut(),
1956            vec![Edit {
1957                old: start..prev_len,
1958                new: start..start,
1959            }],
1960            DiffChangeKind::BufferEdited,
1961        );
1962        if !edits.is_empty() {
1963            self.subscriptions.publish(edits);
1964        }
1965        cx.emit(Event::Edited {
1966            edited_buffer: None,
1967        });
1968        cx.emit(Event::ExcerptsRemoved {
1969            ids,
1970            removed_buffer_ids,
1971        });
1972        cx.notify();
1973    }
1974
1975    #[ztracing::instrument(skip_all)]
1976    pub fn excerpts_for_buffer(
1977        &self,
1978        buffer_id: BufferId,
1979        cx: &App,
1980    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1981        let mut excerpts = Vec::new();
1982        let snapshot = self.read(cx);
1983        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1984        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1985            for locator in locators {
1986                cursor.seek_forward(&Some(locator), Bias::Left);
1987                if let Some(excerpt) = cursor.item()
1988                    && excerpt.locator == *locator
1989                {
1990                    excerpts.push((excerpt.id, excerpt.range.clone()));
1991                }
1992            }
1993        }
1994
1995        excerpts
1996    }
1997
1998    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1999        let snapshot = self.read(cx);
2000        let mut excerpts = snapshot
2001            .excerpts
2002            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2003        let mut diff_transforms = snapshot
2004            .diff_transforms
2005            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2006        diff_transforms.next();
2007        let locators = self
2008            .buffers
2009            .get(&buffer_id)
2010            .into_iter()
2011            .flat_map(|state| &state.excerpts);
2012        let mut result = Vec::new();
2013        for locator in locators {
2014            excerpts.seek_forward(&Some(locator), Bias::Left);
2015            if let Some(excerpt) = excerpts.item()
2016                && excerpt.locator == *locator
2017            {
2018                let excerpt_start = excerpts.start().1;
2019                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2020
2021                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2022                let overshoot = excerpt_start - diff_transforms.start().0;
2023                let start = diff_transforms.start().1 + overshoot;
2024
2025                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2026                let overshoot = excerpt_end - diff_transforms.start().0;
2027                let end = diff_transforms.start().1 + overshoot;
2028
2029                result.push(start.0..end.0)
2030            }
2031        }
2032        result
2033    }
2034
2035    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2036        self.snapshot
2037            .borrow()
2038            .excerpts
2039            .iter()
2040            .map(|entry| entry.buffer_id)
2041            .collect()
2042    }
2043
2044    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2045        self.snapshot
2046            .borrow()
2047            .excerpts
2048            .iter()
2049            .map(|entry| entry.id)
2050            .collect()
2051    }
2052
2053    pub fn excerpt_containing(
2054        &self,
2055        position: impl ToOffset,
2056        cx: &App,
2057    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2058        let snapshot = self.read(cx);
2059        let offset = position.to_offset(&snapshot);
2060
2061        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2062        cursor.seek(&offset);
2063        cursor
2064            .excerpt()
2065            .or_else(|| snapshot.excerpts.last())
2066            .map(|excerpt| {
2067                (
2068                    excerpt.id,
2069                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2070                    excerpt.range.context.clone(),
2071                )
2072            })
2073    }
2074
2075    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2076        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2077            self.buffer(buffer_id)
2078        } else {
2079            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2080            Some(buffer)
2081        }
2082    }
2083
2084    // If point is at the end of the buffer, the last excerpt is returned
2085    pub fn point_to_buffer_offset<T: ToOffset>(
2086        &self,
2087        point: T,
2088        cx: &App,
2089    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2090        let snapshot = self.read(cx);
2091        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2092        Some((
2093            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2094            offset,
2095        ))
2096    }
2097
2098    // If point is at the end of the buffer, the last excerpt is returned
2099    pub fn point_to_buffer_point<T: ToPoint>(
2100        &self,
2101        point: T,
2102        cx: &App,
2103    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2104        let snapshot = self.read(cx);
2105        let (buffer, point, is_main_buffer) =
2106            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2107        Some((
2108            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2109            point,
2110            is_main_buffer,
2111        ))
2112    }
2113
2114    pub fn buffer_point_to_anchor(
2115        &self,
2116        buffer: &Entity<Buffer>,
2117        point: Point,
2118        cx: &App,
2119    ) -> Option<Anchor> {
2120        let mut found = None;
2121        let snapshot = buffer.read(cx).snapshot();
2122        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2123            let start = range.context.start.to_point(&snapshot);
2124            let end = range.context.end.to_point(&snapshot);
2125            if start <= point && point < end {
2126                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2127                break;
2128            }
2129            if point < start {
2130                found = Some((start, excerpt_id));
2131            }
2132            if point > end {
2133                found = Some((end, excerpt_id));
2134            }
2135        }
2136
2137        found.map(|(point, excerpt_id)| {
2138            let text_anchor = snapshot.anchor_after(point);
2139            Anchor::in_buffer(excerpt_id, text_anchor)
2140        })
2141    }
2142
2143    pub fn buffer_anchor_to_anchor(
2144        &self,
2145        buffer: &Entity<Buffer>,
2146        anchor: text::Anchor,
2147        cx: &App,
2148    ) -> Option<Anchor> {
2149        let snapshot = buffer.read(cx).snapshot();
2150        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2151            if range.context.start.cmp(&anchor, &snapshot).is_le()
2152                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2153            {
2154                return Some(Anchor::in_buffer(excerpt_id, anchor));
2155            }
2156        }
2157
2158        None
2159    }
2160
2161    pub fn remove_excerpts(
2162        &mut self,
2163        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2164        cx: &mut Context<Self>,
2165    ) {
2166        self.sync_mut(cx);
2167        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2168        if ids.is_empty() {
2169            return;
2170        }
2171        self.buffer_changed_since_sync.replace(true);
2172
2173        let mut snapshot = self.snapshot.get_mut();
2174        let mut new_excerpts = SumTree::default();
2175        let mut cursor = snapshot
2176            .excerpts
2177            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2178        let mut edits = Vec::new();
2179        let mut excerpt_ids = ids.iter().copied().peekable();
2180        let mut removed_buffer_ids = Vec::new();
2181
2182        while let Some(excerpt_id) = excerpt_ids.next() {
2183            self.paths_by_excerpt.remove(&excerpt_id);
2184            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2185            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2186            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2187
2188            if let Some(mut excerpt) = cursor.item() {
2189                if excerpt.id != excerpt_id {
2190                    continue;
2191                }
2192                let mut old_start = cursor.start().1;
2193
2194                // Skip over the removed excerpt.
2195                'remove_excerpts: loop {
2196                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2197                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2198                        if buffer_state.excerpts.is_empty() {
2199                            log::debug!(
2200                                "removing buffer and diff for buffer {}",
2201                                excerpt.buffer_id
2202                            );
2203                            self.buffers.remove(&excerpt.buffer_id);
2204                            removed_buffer_ids.push(excerpt.buffer_id);
2205                        }
2206                    }
2207                    cursor.next();
2208
2209                    // Skip over any subsequent excerpts that are also removed.
2210                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2211                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2212                        if let Some(next_excerpt) = cursor.item()
2213                            && next_excerpt.locator == *next_locator
2214                        {
2215                            excerpt_ids.next();
2216                            excerpt = next_excerpt;
2217                            continue 'remove_excerpts;
2218                        }
2219                    }
2220
2221                    break;
2222                }
2223
2224                // When removing the last excerpt, remove the trailing newline from
2225                // the previous excerpt.
2226                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2227                    old_start -= 1;
2228                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2229                }
2230
2231                // Push an edit for the removal of this run of excerpts.
2232                let old_end = cursor.start().1;
2233                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2234                edits.push(Edit {
2235                    old: old_start..old_end,
2236                    new: new_start..new_start,
2237                });
2238            }
2239        }
2240        let suffix = cursor.suffix();
2241        let changed_trailing_excerpt = suffix.is_empty();
2242        new_excerpts.append(suffix, ());
2243        drop(cursor);
2244        snapshot.excerpts = new_excerpts;
2245        for buffer_id in &removed_buffer_ids {
2246            self.diffs.remove(buffer_id);
2247            snapshot.diffs.remove(buffer_id);
2248        }
2249
2250        // Recalculate has_inverted_diff after removing diffs
2251        if !removed_buffer_ids.is_empty() {
2252            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2253        }
2254
2255        if changed_trailing_excerpt {
2256            snapshot.trailing_excerpt_update_count += 1;
2257        }
2258
2259        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2260        if !edits.is_empty() {
2261            self.subscriptions.publish(edits);
2262        }
2263        cx.emit(Event::Edited {
2264            edited_buffer: None,
2265        });
2266        cx.emit(Event::ExcerptsRemoved {
2267            ids,
2268            removed_buffer_ids,
2269        });
2270        cx.notify();
2271    }
2272
2273    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2274        &self,
2275        anchors: Anchors,
2276        cx: &mut Context<Self>,
2277    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2278        let mut error = None;
2279        let mut futures = Vec::new();
2280        for anchor in anchors {
2281            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2282                if let Some(buffer) = self.buffers.get(&buffer_id) {
2283                    buffer.buffer.update(cx, |buffer, _| {
2284                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2285                    });
2286                } else {
2287                    error = Some(anyhow!(
2288                        "buffer {buffer_id} is not part of this multi-buffer"
2289                    ));
2290                    break;
2291                }
2292            }
2293        }
2294        async move {
2295            if let Some(error) = error {
2296                Err(error)?;
2297            }
2298            for future in futures {
2299                future.await?;
2300            }
2301            Ok(())
2302        }
2303    }
2304
2305    pub fn text_anchor_for_position<T: ToOffset>(
2306        &self,
2307        position: T,
2308        cx: &App,
2309    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2310        let snapshot = self.read(cx);
2311        let anchor = snapshot.anchor_before(position);
2312        let buffer = self
2313            .buffers
2314            .get(&anchor.text_anchor.buffer_id?)?
2315            .buffer
2316            .clone();
2317        Some((buffer, anchor.text_anchor))
2318    }
2319
2320    fn on_buffer_event(
2321        &mut self,
2322        buffer: Entity<Buffer>,
2323        event: &language::BufferEvent,
2324        cx: &mut Context<Self>,
2325    ) {
2326        use language::BufferEvent;
2327        let buffer_id = buffer.read(cx).remote_id();
2328        cx.emit(match event {
2329            BufferEvent::Edited => Event::Edited {
2330                edited_buffer: Some(buffer),
2331            },
2332            BufferEvent::DirtyChanged => Event::DirtyChanged,
2333            BufferEvent::Saved => Event::Saved,
2334            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2335            BufferEvent::Reloaded => Event::Reloaded,
2336            BufferEvent::LanguageChanged(has_language) => {
2337                Event::LanguageChanged(buffer_id, *has_language)
2338            }
2339            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2340            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2341            BufferEvent::CapabilityChanged => {
2342                self.capability = buffer.read(cx).capability();
2343                return;
2344            }
2345            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2346        });
2347    }
2348
2349    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2350        let diff = diff.read(cx);
2351        let buffer_id = diff.buffer_id;
2352        let diff = DiffStateSnapshot {
2353            diff: diff.snapshot(cx),
2354            is_inverted: false,
2355        };
2356        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2357    }
2358
2359    fn inverted_buffer_diff_language_changed(
2360        &mut self,
2361        diff: Entity<BufferDiff>,
2362        cx: &mut Context<Self>,
2363    ) {
2364        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2365        let diff = diff.read(cx);
2366        let diff = DiffStateSnapshot {
2367            diff: diff.snapshot(cx),
2368            is_inverted: true,
2369        };
2370        self.snapshot
2371            .get_mut()
2372            .diffs
2373            .insert(base_text_buffer_id, diff);
2374    }
2375
2376    fn buffer_diff_changed(
2377        &mut self,
2378        diff: Entity<BufferDiff>,
2379        range: Range<text::Anchor>,
2380        cx: &mut Context<Self>,
2381    ) {
2382        self.sync_mut(cx);
2383
2384        let diff = diff.read(cx);
2385        let buffer_id = diff.buffer_id;
2386
2387        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2388            return;
2389        };
2390        let new_diff = DiffStateSnapshot {
2391            diff: diff.snapshot(cx),
2392            is_inverted: false,
2393        };
2394        let mut snapshot = self.snapshot.get_mut();
2395        let base_text_changed = snapshot
2396            .diffs
2397            .get(&buffer_id)
2398            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2399        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2400
2401        let buffer = buffer_state.buffer.read(cx);
2402        let diff_change_range = range.to_offset(buffer);
2403
2404        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2405        let edits = Self::sync_diff_transforms(
2406            &mut snapshot,
2407            excerpt_edits,
2408            DiffChangeKind::DiffUpdated {
2409                base_changed: base_text_changed,
2410            },
2411        );
2412        if !edits.is_empty() {
2413            self.subscriptions.publish(edits);
2414        }
2415        cx.emit(Event::Edited {
2416            edited_buffer: None,
2417        });
2418    }
2419
2420    fn inverted_buffer_diff_changed(
2421        &mut self,
2422        diff: Entity<BufferDiff>,
2423        diff_change_range: Range<usize>,
2424        cx: &mut Context<Self>,
2425    ) {
2426        self.sync_mut(cx);
2427
2428        let diff = diff.read(cx);
2429        let base_text_buffer_id = diff.base_text(cx).remote_id();
2430        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2431            return;
2432        };
2433
2434        let new_diff = DiffStateSnapshot {
2435            diff: diff.snapshot(cx),
2436            is_inverted: true,
2437        };
2438        let mut snapshot = self.snapshot.get_mut();
2439        snapshot
2440            .diffs
2441            .insert_or_replace(base_text_buffer_id, new_diff);
2442
2443        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2444        let edits = Self::sync_diff_transforms(
2445            &mut snapshot,
2446            excerpt_edits,
2447            DiffChangeKind::DiffUpdated {
2448                // We don't read this field for inverted diffs.
2449                base_changed: false,
2450            },
2451        );
2452        if !edits.is_empty() {
2453            self.subscriptions.publish(edits);
2454        }
2455        cx.emit(Event::Edited {
2456            edited_buffer: None,
2457        });
2458    }
2459
2460    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2461        self.buffers.values().map(|state| state.buffer.clone())
2462    }
2463
2464    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2465        self.all_buffers_iter().collect()
2466    }
2467
2468    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2469        self.buffers.keys().copied()
2470    }
2471
2472    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2473        self.all_buffer_ids_iter().collect()
2474    }
2475
2476    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2477        self.buffers
2478            .get(&buffer_id)
2479            .map(|state| state.buffer.clone())
2480    }
2481
2482    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2483        self.point_to_buffer_offset(point, cx)
2484            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2485    }
2486
2487    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2488        let buffer_id = self
2489            .snapshot
2490            .borrow()
2491            .excerpts
2492            .first()
2493            .map(|excerpt| excerpt.buffer.remote_id());
2494        buffer_id
2495            .and_then(|buffer_id| self.buffer(buffer_id))
2496            .map(|buffer| {
2497                let buffer = buffer.read(cx);
2498                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2499            })
2500            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2501    }
2502
2503    pub fn language_settings_at<'a, T: ToOffset>(
2504        &'a self,
2505        point: T,
2506        cx: &'a App,
2507    ) -> Cow<'a, LanguageSettings> {
2508        let mut language = None;
2509        let mut file = None;
2510        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2511            let buffer = buffer.read(cx);
2512            language = buffer.language_at(offset);
2513            file = buffer.file();
2514        }
2515        language_settings(language.map(|l| l.name()), file, cx)
2516    }
2517
2518    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2519        self.buffers.values().for_each(|state| f(&state.buffer))
2520    }
2521
2522    pub fn explicit_title(&self) -> Option<&str> {
2523        self.title.as_deref()
2524    }
2525
2526    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2527        if let Some(title) = self.title.as_ref() {
2528            return title.into();
2529        }
2530
2531        if let Some(buffer) = self.as_singleton() {
2532            let buffer = buffer.read(cx);
2533
2534            if let Some(file) = buffer.file() {
2535                return file.file_name(cx).into();
2536            }
2537
2538            if let Some(title) = self.buffer_content_title(buffer) {
2539                return title;
2540            }
2541        };
2542
2543        "untitled".into()
2544    }
2545
2546    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2547        let mut is_leading_whitespace = true;
2548        let mut count = 0;
2549        let mut prev_was_space = false;
2550        let mut title = String::new();
2551
2552        for ch in buffer.snapshot().chars() {
2553            if is_leading_whitespace && ch.is_whitespace() {
2554                continue;
2555            }
2556
2557            is_leading_whitespace = false;
2558
2559            if ch == '\n' || count >= 40 {
2560                break;
2561            }
2562
2563            if ch.is_whitespace() {
2564                if !prev_was_space {
2565                    title.push(' ');
2566                    count += 1;
2567                    prev_was_space = true;
2568                }
2569            } else {
2570                title.push(ch);
2571                count += 1;
2572                prev_was_space = false;
2573            }
2574        }
2575
2576        let title = title.trim_end().to_string();
2577
2578        if title.is_empty() {
2579            return None;
2580        }
2581
2582        Some(title.into())
2583    }
2584
2585    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2586        self.title = Some(title);
2587        cx.notify();
2588    }
2589
2590    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2591    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2592        for buffer_state in self.buffers.values() {
2593            buffer_state
2594                .buffer
2595                .update(cx, |buffer, _cx| buffer.refresh_preview());
2596        }
2597    }
2598
2599    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2600    pub fn preserve_preview(&self, cx: &App) -> bool {
2601        self.buffers
2602            .values()
2603            .all(|state| state.buffer.read(cx).preserve_preview())
2604    }
2605
2606    #[cfg(any(test, feature = "test-support"))]
2607    pub fn is_parsing(&self, cx: &App) -> bool {
2608        self.as_singleton().unwrap().read(cx).is_parsing()
2609    }
2610
2611    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2612        let buffer_id = diff.read(cx).buffer_id;
2613
2614        if let Some(existing_diff) = self.diff_for(buffer_id)
2615            && diff.entity_id() == existing_diff.entity_id()
2616        {
2617            return;
2618        }
2619
2620        self.buffer_diff_changed(
2621            diff.clone(),
2622            text::Anchor::min_max_range_for_buffer(buffer_id),
2623            cx,
2624        );
2625        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2626    }
2627
2628    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2629        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2630        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2631        self.snapshot.get_mut().has_inverted_diff = true;
2632        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2633        self.diffs
2634            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2635    }
2636
2637    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2638        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2639    }
2640
2641    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2642        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2643    }
2644
2645    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2646        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2647    }
2648
2649    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2650        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2651        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2652    }
2653
2654    pub fn all_diff_hunks_expanded(&self) -> bool {
2655        self.snapshot.borrow().all_diff_hunks_expanded
2656    }
2657
2658    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2659        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2660        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2661    }
2662
2663    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2664        self.snapshot.get_mut().show_deleted_hunks = show;
2665        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2666    }
2667
2668    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2669        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2670    }
2671
2672    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2673        self.read(cx)
2674            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2675            .nth(1)
2676            .is_some()
2677    }
2678
2679    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2680        let snapshot = self.read(cx);
2681        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2682        let offset_range = range.to_offset(&snapshot);
2683        cursor.seek(&offset_range.start, Bias::Left);
2684        while let Some(item) = cursor.item() {
2685            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2686                break;
2687            }
2688            if item.hunk_info().is_some() {
2689                return true;
2690            }
2691            cursor.next();
2692        }
2693        false
2694    }
2695
2696    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2697        let snapshot = self.read(cx);
2698        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2699        for range in ranges {
2700            let range = range.to_point(&snapshot);
2701            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2702            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2703                .min(snapshot.len());
2704            cursor.seek(&start, Bias::Right);
2705            while let Some(item) = cursor.item() {
2706                if *cursor.start() >= end {
2707                    break;
2708                }
2709                if item.hunk_info().is_some() {
2710                    return true;
2711                }
2712                cursor.next();
2713            }
2714        }
2715        false
2716    }
2717
2718    pub fn expand_or_collapse_diff_hunks_inner(
2719        &mut self,
2720        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2721        expand: bool,
2722        cx: &mut Context<Self>,
2723    ) {
2724        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2725            return;
2726        }
2727        self.sync_mut(cx);
2728        let mut snapshot = self.snapshot.get_mut();
2729        let mut excerpt_edits = Vec::new();
2730        let mut last_hunk_row = None;
2731        for (range, end_excerpt_id) in ranges {
2732            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2733                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2734                    continue;
2735                }
2736                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2737                    continue;
2738                }
2739                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2740                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2741                let start = snapshot.excerpt_offset_for_anchor(&start);
2742                let end = snapshot.excerpt_offset_for_anchor(&end);
2743                last_hunk_row = Some(diff_hunk.row_range.start);
2744                excerpt_edits.push(text::Edit {
2745                    old: start..end,
2746                    new: start..end,
2747                });
2748            }
2749        }
2750
2751        let edits = Self::sync_diff_transforms(
2752            &mut snapshot,
2753            excerpt_edits,
2754            DiffChangeKind::ExpandOrCollapseHunks { expand },
2755        );
2756        if !edits.is_empty() {
2757            self.subscriptions.publish(edits);
2758        }
2759        cx.emit(Event::DiffHunksToggled);
2760        cx.emit(Event::Edited {
2761            edited_buffer: None,
2762        });
2763    }
2764
2765    pub fn expand_or_collapse_diff_hunks(
2766        &mut self,
2767        ranges: Vec<Range<Anchor>>,
2768        expand: bool,
2769        cx: &mut Context<Self>,
2770    ) {
2771        let snapshot = self.snapshot.borrow().clone();
2772        let ranges = ranges.iter().map(move |range| {
2773            let end_excerpt_id = range.end.excerpt_id;
2774            let range = range.to_point(&snapshot);
2775            let mut peek_end = range.end;
2776            if range.end.row < snapshot.max_row().0 {
2777                peek_end = Point::new(range.end.row + 1, 0);
2778            };
2779            (range.start..peek_end, end_excerpt_id)
2780        });
2781        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2782    }
2783
2784    pub fn resize_excerpt(
2785        &mut self,
2786        id: ExcerptId,
2787        range: Range<text::Anchor>,
2788        cx: &mut Context<Self>,
2789    ) {
2790        self.sync_mut(cx);
2791
2792        let mut snapshot = self.snapshot.get_mut();
2793        let locator = snapshot.excerpt_locator_for_id(id);
2794        let mut new_excerpts = SumTree::default();
2795        let mut cursor = snapshot
2796            .excerpts
2797            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2798        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2799
2800        let prefix = cursor.slice(&Some(locator), Bias::Left);
2801        new_excerpts.append(prefix, ());
2802
2803        let mut excerpt = cursor.item().unwrap().clone();
2804        let old_text_len = excerpt.text_summary.len;
2805
2806        excerpt.range.context.start = range.start;
2807        excerpt.range.context.end = range.end;
2808        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2809
2810        excerpt.text_summary = excerpt
2811            .buffer
2812            .text_summary_for_range(excerpt.range.context.clone());
2813
2814        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2815        let old_start_offset = cursor.start().1;
2816        let new_text_len = excerpt.text_summary.len;
2817        let edit = Edit {
2818            old: old_start_offset..old_start_offset + old_text_len,
2819            new: new_start_offset..new_start_offset + new_text_len,
2820        };
2821
2822        if let Some(last_edit) = edits.last_mut() {
2823            if last_edit.old.end == edit.old.start {
2824                last_edit.old.end = edit.old.end;
2825                last_edit.new.end = edit.new.end;
2826            } else {
2827                edits.push(edit);
2828            }
2829        } else {
2830            edits.push(edit);
2831        }
2832
2833        new_excerpts.push(excerpt, ());
2834
2835        cursor.next();
2836
2837        new_excerpts.append(cursor.suffix(), ());
2838
2839        drop(cursor);
2840        snapshot.excerpts = new_excerpts;
2841
2842        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2843        if !edits.is_empty() {
2844            self.subscriptions.publish(edits);
2845        }
2846        cx.emit(Event::Edited {
2847            edited_buffer: None,
2848        });
2849        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2850        cx.notify();
2851    }
2852
2853    pub fn expand_excerpts(
2854        &mut self,
2855        ids: impl IntoIterator<Item = ExcerptId>,
2856        line_count: u32,
2857        direction: ExpandExcerptDirection,
2858        cx: &mut Context<Self>,
2859    ) {
2860        if line_count == 0 {
2861            return;
2862        }
2863        self.sync_mut(cx);
2864        if !self.excerpts_by_path.is_empty() {
2865            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2866            return;
2867        }
2868        let mut snapshot = self.snapshot.get_mut();
2869
2870        let ids = ids.into_iter().collect::<Vec<_>>();
2871        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2872        let mut new_excerpts = SumTree::default();
2873        let mut cursor = snapshot
2874            .excerpts
2875            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2876        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2877
2878        for locator in &locators {
2879            let prefix = cursor.slice(&Some(locator), Bias::Left);
2880            new_excerpts.append(prefix, ());
2881
2882            let mut excerpt = cursor.item().unwrap().clone();
2883            let old_text_len = excerpt.text_summary.len;
2884
2885            let up_line_count = if direction.should_expand_up() {
2886                line_count
2887            } else {
2888                0
2889            };
2890
2891            let start_row = excerpt
2892                .range
2893                .context
2894                .start
2895                .to_point(&excerpt.buffer)
2896                .row
2897                .saturating_sub(up_line_count);
2898            let start_point = Point::new(start_row, 0);
2899            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2900
2901            let down_line_count = if direction.should_expand_down() {
2902                line_count
2903            } else {
2904                0
2905            };
2906
2907            let mut end_point = excerpt.buffer.clip_point(
2908                excerpt.range.context.end.to_point(&excerpt.buffer)
2909                    + Point::new(down_line_count, 0),
2910                Bias::Left,
2911            );
2912            end_point.column = excerpt.buffer.line_len(end_point.row);
2913            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2914            excerpt.max_buffer_row = end_point.row;
2915
2916            excerpt.text_summary = excerpt
2917                .buffer
2918                .text_summary_for_range(excerpt.range.context.clone());
2919
2920            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2921            let old_start_offset = cursor.start().1;
2922            let new_text_len = excerpt.text_summary.len;
2923            let edit = Edit {
2924                old: old_start_offset..old_start_offset + old_text_len,
2925                new: new_start_offset..new_start_offset + new_text_len,
2926            };
2927
2928            if let Some(last_edit) = edits.last_mut() {
2929                if last_edit.old.end == edit.old.start {
2930                    last_edit.old.end = edit.old.end;
2931                    last_edit.new.end = edit.new.end;
2932                } else {
2933                    edits.push(edit);
2934                }
2935            } else {
2936                edits.push(edit);
2937            }
2938
2939            new_excerpts.push(excerpt, ());
2940
2941            cursor.next();
2942        }
2943
2944        new_excerpts.append(cursor.suffix(), ());
2945
2946        drop(cursor);
2947        snapshot.excerpts = new_excerpts;
2948
2949        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2950        if !edits.is_empty() {
2951            self.subscriptions.publish(edits);
2952        }
2953        cx.emit(Event::Edited {
2954            edited_buffer: None,
2955        });
2956        cx.emit(Event::ExcerptsExpanded { ids });
2957        cx.notify();
2958    }
2959
2960    #[ztracing::instrument(skip_all)]
2961    fn sync(&self, cx: &App) {
2962        let changed = self.buffer_changed_since_sync.replace(false);
2963        if !changed {
2964            return;
2965        }
2966        let edits = Self::sync_from_buffer_changes(
2967            &mut self.snapshot.borrow_mut(),
2968            &self.buffers,
2969            &self.diffs,
2970            cx,
2971        );
2972        if !edits.is_empty() {
2973            self.subscriptions.publish(edits);
2974        }
2975    }
2976
2977    fn sync_mut(&mut self, cx: &App) {
2978        let changed = self.buffer_changed_since_sync.replace(false);
2979        if !changed {
2980            return;
2981        }
2982        let edits =
2983            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2984
2985        if !edits.is_empty() {
2986            self.subscriptions.publish(edits);
2987        }
2988    }
2989
2990    fn sync_from_buffer_changes(
2991        snapshot: &mut MultiBufferSnapshot,
2992        buffers: &BTreeMap<BufferId, BufferState>,
2993        diffs: &HashMap<BufferId, DiffState>,
2994        cx: &App,
2995    ) -> Vec<Edit<MultiBufferOffset>> {
2996        let MultiBufferSnapshot {
2997            excerpts,
2998            diffs: buffer_diff,
2999            diff_transforms: _,
3000            non_text_state_update_count,
3001            edit_count,
3002            is_dirty,
3003            has_deleted_file,
3004            has_conflict,
3005            has_inverted_diff: _,
3006            singleton: _,
3007            excerpt_ids: _,
3008            replaced_excerpts: _,
3009            trailing_excerpt_update_count: _,
3010            all_diff_hunks_expanded: _,
3011            show_deleted_hunks: _,
3012            use_extended_diff_range: _,
3013            show_headers: _,
3014        } = snapshot;
3015        *is_dirty = false;
3016        *has_deleted_file = false;
3017        *has_conflict = false;
3018
3019        let mut excerpts_to_edit = Vec::new();
3020        let mut non_text_state_updated = false;
3021        let mut edited = false;
3022        for buffer_state in buffers.values() {
3023            let buffer = buffer_state.buffer.read(cx);
3024            let version = buffer.version();
3025            let non_text_state_update_count = buffer.non_text_state_update_count();
3026
3027            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3028            let buffer_non_text_state_updated =
3029                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3030            if buffer_edited || buffer_non_text_state_updated {
3031                *buffer_state.last_version.borrow_mut() = version;
3032                buffer_state
3033                    .last_non_text_state_update_count
3034                    .set(non_text_state_update_count);
3035                excerpts_to_edit.extend(
3036                    buffer_state
3037                        .excerpts
3038                        .iter()
3039                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3040                );
3041            }
3042
3043            edited |= buffer_edited;
3044            non_text_state_updated |= buffer_non_text_state_updated;
3045            *is_dirty |= buffer.is_dirty();
3046            *has_deleted_file |= buffer
3047                .file()
3048                .is_some_and(|file| file.disk_state().is_deleted());
3049            *has_conflict |= buffer.has_conflict();
3050        }
3051        if edited {
3052            *edit_count += 1;
3053        }
3054        if non_text_state_updated {
3055            *non_text_state_update_count += 1;
3056        }
3057
3058        for (id, diff) in diffs.iter() {
3059            if buffer_diff.get(id).is_none() || diff.is_inverted {
3060                buffer_diff.insert(*id, diff.snapshot(cx));
3061            }
3062        }
3063
3064        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3065
3066        let mut edits = Vec::new();
3067        let mut new_excerpts = SumTree::default();
3068        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3069
3070        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3071            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3072            let old_excerpt = cursor.item().unwrap();
3073            let buffer = buffer.read(cx);
3074            let buffer_id = buffer.remote_id();
3075
3076            let mut new_excerpt;
3077            if buffer_edited {
3078                edits.extend(
3079                    buffer
3080                        .edits_since_in_range::<usize>(
3081                            old_excerpt.buffer.version(),
3082                            old_excerpt.range.context.clone(),
3083                        )
3084                        .map(|edit| {
3085                            let excerpt_old_start = cursor.start().1;
3086                            let excerpt_new_start =
3087                                ExcerptDimension(new_excerpts.summary().text.len);
3088                            let old_start = excerpt_old_start + edit.old.start;
3089                            let old_end = excerpt_old_start + edit.old.end;
3090                            let new_start = excerpt_new_start + edit.new.start;
3091                            let new_end = excerpt_new_start + edit.new.end;
3092                            Edit {
3093                                old: old_start..old_end,
3094                                new: new_start..new_end,
3095                            }
3096                        }),
3097                );
3098
3099                new_excerpt = Excerpt::new(
3100                    old_excerpt.id,
3101                    locator.clone(),
3102                    buffer_id,
3103                    buffer.snapshot(),
3104                    old_excerpt.range.clone(),
3105                    old_excerpt.has_trailing_newline,
3106                );
3107            } else {
3108                new_excerpt = old_excerpt.clone();
3109                new_excerpt.buffer = buffer.snapshot();
3110            }
3111
3112            new_excerpts.push(new_excerpt, ());
3113            cursor.next();
3114        }
3115        new_excerpts.append(cursor.suffix(), ());
3116
3117        drop(cursor);
3118        *excerpts = new_excerpts;
3119
3120        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3121    }
3122
3123    fn sync_diff_transforms(
3124        snapshot: &mut MultiBufferSnapshot,
3125        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3126        change_kind: DiffChangeKind,
3127    ) -> Vec<Edit<MultiBufferOffset>> {
3128        if excerpt_edits.is_empty() {
3129            return vec![];
3130        }
3131
3132        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3133        let mut old_diff_transforms = snapshot
3134            .diff_transforms
3135            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3136        let mut new_diff_transforms = SumTree::default();
3137        let mut old_expanded_hunks = HashSet::default();
3138        let mut output_edits = Vec::new();
3139        let mut output_delta = 0_isize;
3140        let mut at_transform_boundary = true;
3141        let mut end_of_current_insert = None;
3142
3143        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3144        while let Some(edit) = excerpt_edits.next() {
3145            excerpts.seek_forward(&edit.new.start, Bias::Right);
3146            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3147                excerpts.prev();
3148            }
3149
3150            // Keep any transforms that are before the edit.
3151            if at_transform_boundary {
3152                at_transform_boundary = false;
3153                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3154                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3155                if let Some(transform) = old_diff_transforms.item()
3156                    && old_diff_transforms.end().0 == edit.old.start
3157                    && old_diff_transforms.start().0 < edit.old.start
3158                {
3159                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3160                    old_diff_transforms.next();
3161                }
3162            }
3163
3164            // Compute the start of the edit in output coordinates.
3165            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3166            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3167            let edit_new_start =
3168                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3169
3170            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3171                &edit,
3172                &mut excerpts,
3173                &mut old_diff_transforms,
3174                &mut new_diff_transforms,
3175                &mut end_of_current_insert,
3176                &mut old_expanded_hunks,
3177                snapshot,
3178                change_kind,
3179            );
3180
3181            // Compute the end of the edit in output coordinates.
3182            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3183            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3184            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3185            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3186            let output_edit = Edit {
3187                old: edit_old_start..edit_old_end,
3188                new: edit_new_start..edit_new_end,
3189            };
3190
3191            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3192            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3193            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3194                output_edits.push(output_edit);
3195            }
3196
3197            // If this is the last edit that intersects the current diff transform,
3198            // then recreate the content up to the end of this transform, to prepare
3199            // for reusing additional slices of the old transforms.
3200            if excerpt_edits
3201                .peek()
3202                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3203            {
3204                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3205                    && match old_diff_transforms.item() {
3206                        Some(DiffTransform::BufferContent {
3207                            inserted_hunk_info: Some(hunk),
3208                            ..
3209                        }) => excerpts.item().is_some_and(|excerpt| {
3210                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3211                                && diff.is_inverted
3212                            {
3213                                return true;
3214                            }
3215                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3216                        }),
3217                        _ => true,
3218                    };
3219
3220                let mut excerpt_offset = edit.new.end;
3221                if !keep_next_old_transform {
3222                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3223                    old_diff_transforms.next();
3224                }
3225
3226                old_expanded_hunks.clear();
3227                Self::push_buffer_content_transform(
3228                    snapshot,
3229                    &mut new_diff_transforms,
3230                    excerpt_offset,
3231                    end_of_current_insert,
3232                );
3233                at_transform_boundary = true;
3234            }
3235        }
3236
3237        // Keep any transforms that are after the last edit.
3238        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3239
3240        // Ensure there's always at least one buffer content transform.
3241        if new_diff_transforms.is_empty() {
3242            new_diff_transforms.push(
3243                DiffTransform::BufferContent {
3244                    summary: Default::default(),
3245                    inserted_hunk_info: None,
3246                },
3247                (),
3248            );
3249        }
3250
3251        drop(old_diff_transforms);
3252        drop(excerpts);
3253        snapshot.diff_transforms = new_diff_transforms;
3254        snapshot.edit_count += 1;
3255
3256        #[cfg(any(test, feature = "test-support"))]
3257        snapshot.check_invariants();
3258        output_edits
3259    }
3260
3261    fn recompute_diff_transforms_for_edit(
3262        edit: &Edit<ExcerptOffset>,
3263        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3264        old_diff_transforms: &mut Cursor<
3265            DiffTransform,
3266            Dimensions<ExcerptOffset, MultiBufferOffset>,
3267        >,
3268        new_diff_transforms: &mut SumTree<DiffTransform>,
3269        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3270        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3271        snapshot: &MultiBufferSnapshot,
3272        change_kind: DiffChangeKind,
3273    ) -> bool {
3274        log::trace!(
3275            "recomputing diff transform for edit {:?} => {:?}",
3276            edit.old.start..edit.old.end,
3277            edit.new.start..edit.new.end
3278        );
3279
3280        // Record which hunks were previously expanded.
3281        while let Some(item) = old_diff_transforms.item() {
3282            if let Some(hunk_info) = item.hunk_info() {
3283                log::trace!(
3284                    "previously expanded hunk at {:?}",
3285                    old_diff_transforms.start()
3286                );
3287                old_expanded_hunks.insert(hunk_info);
3288            }
3289            if old_diff_transforms.end().0 > edit.old.end {
3290                break;
3291            }
3292            old_diff_transforms.next();
3293        }
3294
3295        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3296        // For inverted diffs, hunks are always shown, so we can't skip this.
3297        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3298        if old_expanded_hunks.is_empty()
3299            && change_kind == DiffChangeKind::BufferEdited
3300            && !all_diff_hunks_expanded
3301            && !snapshot.has_inverted_diff
3302        {
3303            return false;
3304        }
3305
3306        // Visit each excerpt that intersects the edit.
3307        let mut did_expand_hunks = false;
3308        while let Some(excerpt) = excerpts.item() {
3309            // Recompute the expanded hunks in the portion of the excerpt that
3310            // intersects the edit.
3311            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3312                let buffer = &excerpt.buffer;
3313                let excerpt_start = *excerpts.start();
3314                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3315                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3316                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3317                let edit_buffer_start =
3318                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3319                let edit_buffer_end =
3320                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3321                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3322
3323                if diff.is_inverted {
3324                    for hunk in diff.hunks_intersecting_base_text_range(
3325                        edit_buffer_start..edit_buffer_end,
3326                        diff.original_buffer_snapshot(),
3327                    ) {
3328                        did_expand_hunks = true;
3329                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3330                        if hunk_buffer_range.start < excerpt_buffer_start {
3331                            log::trace!("skipping hunk that starts before excerpt");
3332                            continue;
3333                        }
3334                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3335                        let hunk_excerpt_start = excerpt_start
3336                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3337                        let hunk_excerpt_end = excerpt_end
3338                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3339                        Self::push_buffer_content_transform(
3340                            snapshot,
3341                            new_diff_transforms,
3342                            hunk_excerpt_start,
3343                            *end_of_current_insert,
3344                        );
3345                        if !hunk_buffer_range.is_empty() {
3346                            let hunk_info = DiffTransformHunkInfo {
3347                                excerpt_id: excerpt.id,
3348                                hunk_start_anchor: hunk.buffer_range.start,
3349                                hunk_secondary_status: hunk.secondary_status,
3350                                is_logically_deleted: true,
3351                            };
3352                            *end_of_current_insert =
3353                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3354                        }
3355                    }
3356                } else {
3357                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3358                        ..buffer.anchor_after(edit_buffer_end);
3359                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3360                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3361                            continue;
3362                        }
3363
3364                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3365                        if hunk_buffer_range.start < excerpt_buffer_start {
3366                            log::trace!("skipping hunk that starts before excerpt");
3367                            continue;
3368                        }
3369
3370                        let hunk_info = DiffTransformHunkInfo {
3371                            excerpt_id: excerpt.id,
3372                            hunk_start_anchor: hunk.buffer_range.start,
3373                            hunk_secondary_status: hunk.secondary_status,
3374                            is_logically_deleted: false,
3375                        };
3376
3377                        let hunk_excerpt_start = excerpt_start
3378                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3379                        let hunk_excerpt_end = excerpt_end
3380                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3381
3382                        Self::push_buffer_content_transform(
3383                            snapshot,
3384                            new_diff_transforms,
3385                            hunk_excerpt_start,
3386                            *end_of_current_insert,
3387                        );
3388
3389                        // For every existing hunk, determine if it was previously expanded
3390                        // and if it should currently be expanded.
3391                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3392                        let should_expand_hunk = match &change_kind {
3393                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3394                                was_previously_expanded || all_diff_hunks_expanded
3395                            }
3396                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3397                                let intersects = hunk_buffer_range.is_empty()
3398                                    || hunk_buffer_range.end > edit_buffer_start;
3399                                if *expand {
3400                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3401                                } else {
3402                                    !intersects
3403                                        && (was_previously_expanded || all_diff_hunks_expanded)
3404                                }
3405                            }
3406                            _ => was_previously_expanded || all_diff_hunks_expanded,
3407                        };
3408
3409                        if should_expand_hunk {
3410                            did_expand_hunks = true;
3411                            log::trace!(
3412                                "expanding hunk {:?}, excerpt:{:?}",
3413                                hunk_excerpt_start..hunk_excerpt_end,
3414                                excerpt.id
3415                            );
3416
3417                            if !hunk.diff_base_byte_range.is_empty()
3418                                && hunk_buffer_range.start >= edit_buffer_start
3419                                && hunk_buffer_range.start <= excerpt_buffer_end
3420                                && snapshot.show_deleted_hunks
3421                            {
3422                                let base_text = diff.base_text();
3423                                let mut text_cursor =
3424                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3425                                let mut base_text_summary = text_cursor
3426                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3427
3428                                let mut has_trailing_newline = false;
3429                                if base_text_summary.last_line_chars > 0 {
3430                                    base_text_summary += TextSummary::newline();
3431                                    has_trailing_newline = true;
3432                                }
3433
3434                                new_diff_transforms.push(
3435                                    DiffTransform::DeletedHunk {
3436                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3437                                        summary: base_text_summary,
3438                                        buffer_id: excerpt.buffer_id,
3439                                        hunk_info,
3440                                        has_trailing_newline,
3441                                    },
3442                                    (),
3443                                );
3444                            }
3445
3446                            if !hunk_buffer_range.is_empty() {
3447                                *end_of_current_insert =
3448                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3449                            }
3450                        }
3451                    }
3452                }
3453            }
3454
3455            if excerpts.end() <= edit.new.end {
3456                excerpts.next();
3457            } else {
3458                break;
3459            }
3460        }
3461
3462        did_expand_hunks || !old_expanded_hunks.is_empty()
3463    }
3464
3465    fn append_diff_transforms(
3466        new_transforms: &mut SumTree<DiffTransform>,
3467        subtree: SumTree<DiffTransform>,
3468    ) {
3469        if let Some(DiffTransform::BufferContent {
3470            inserted_hunk_info,
3471            summary,
3472        }) = subtree.first()
3473            && Self::extend_last_buffer_content_transform(
3474                new_transforms,
3475                *inserted_hunk_info,
3476                *summary,
3477            )
3478        {
3479            let mut cursor = subtree.cursor::<()>(());
3480            cursor.next();
3481            cursor.next();
3482            new_transforms.append(cursor.suffix(), ());
3483            return;
3484        }
3485        new_transforms.append(subtree, ());
3486    }
3487
3488    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3489        if let DiffTransform::BufferContent {
3490            inserted_hunk_info: inserted_hunk_anchor,
3491            summary,
3492        } = transform
3493            && Self::extend_last_buffer_content_transform(
3494                new_transforms,
3495                inserted_hunk_anchor,
3496                summary,
3497            )
3498        {
3499            return;
3500        }
3501        new_transforms.push(transform, ());
3502    }
3503
3504    fn push_buffer_content_transform(
3505        old_snapshot: &MultiBufferSnapshot,
3506        new_transforms: &mut SumTree<DiffTransform>,
3507        end_offset: ExcerptOffset,
3508        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3509    ) {
3510        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3511            (end_offset.min(insertion_end_offset), Some(hunk_info))
3512        });
3513        let unchanged_region = [(end_offset, None)];
3514
3515        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3516        {
3517            let start_offset = new_transforms.summary().excerpt_len();
3518            if end_offset <= start_offset {
3519                continue;
3520            }
3521            let summary_to_add = old_snapshot
3522                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3523
3524            if !Self::extend_last_buffer_content_transform(
3525                new_transforms,
3526                inserted_hunk_info,
3527                summary_to_add,
3528            ) {
3529                new_transforms.push(
3530                    DiffTransform::BufferContent {
3531                        summary: summary_to_add,
3532                        inserted_hunk_info,
3533                    },
3534                    (),
3535                )
3536            }
3537        }
3538    }
3539
3540    fn extend_last_buffer_content_transform(
3541        new_transforms: &mut SumTree<DiffTransform>,
3542        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3543        summary_to_add: MBTextSummary,
3544    ) -> bool {
3545        let mut did_extend = false;
3546        new_transforms.update_last(
3547            |last_transform| {
3548                if let DiffTransform::BufferContent {
3549                    summary,
3550                    inserted_hunk_info: inserted_hunk_anchor,
3551                } = last_transform
3552                    && *inserted_hunk_anchor == new_inserted_hunk_info
3553                {
3554                    *summary += summary_to_add;
3555                    did_extend = true;
3556                }
3557            },
3558            (),
3559        );
3560        did_extend
3561    }
3562}
3563
3564fn build_excerpt_ranges(
3565    ranges: impl IntoIterator<Item = Range<Point>>,
3566    context_line_count: u32,
3567    buffer_snapshot: &BufferSnapshot,
3568) -> Vec<ExcerptRange<Point>> {
3569    ranges
3570        .into_iter()
3571        .map(|range| {
3572            let start_row = range.start.row.saturating_sub(context_line_count);
3573            let start = Point::new(start_row, 0);
3574            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3575            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3576            ExcerptRange {
3577                context: start..end,
3578                primary: range,
3579            }
3580        })
3581        .collect()
3582}
3583
3584#[cfg(any(test, feature = "test-support"))]
3585impl MultiBuffer {
3586    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3587        let buffer = cx.new(|cx| Buffer::local(text, cx));
3588        cx.new(|cx| Self::singleton(buffer, cx))
3589    }
3590
3591    pub fn build_multi<const COUNT: usize>(
3592        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3593        cx: &mut gpui::App,
3594    ) -> Entity<Self> {
3595        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3596        for (text, ranges) in excerpts {
3597            let buffer = cx.new(|cx| Buffer::local(text, cx));
3598            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3599            multi.update(cx, |multi, cx| {
3600                multi.push_excerpts(buffer, excerpt_ranges, cx)
3601            });
3602        }
3603
3604        multi
3605    }
3606
3607    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3608        cx.new(|cx| Self::singleton(buffer, cx))
3609    }
3610
3611    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3612        cx.new(|cx| {
3613            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3614            let mutation_count = rng.random_range(1..=5);
3615            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3616            multibuffer
3617        })
3618    }
3619
3620    pub fn randomly_edit(
3621        &mut self,
3622        rng: &mut impl rand::Rng,
3623        edit_count: usize,
3624        cx: &mut Context<Self>,
3625    ) {
3626        use util::RandomCharIter;
3627
3628        let snapshot = self.read(cx);
3629        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3630        let mut last_end = None;
3631        for _ in 0..edit_count {
3632            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3633                break;
3634            }
3635
3636            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3637            let end =
3638                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3639            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3640            last_end = Some(end);
3641
3642            let mut range = start..end;
3643            if rng.random_bool(0.2) {
3644                mem::swap(&mut range.start, &mut range.end);
3645            }
3646
3647            let new_text_len = rng.random_range(0..10);
3648            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3649
3650            edits.push((range, new_text.into()));
3651        }
3652        log::info!("mutating multi-buffer with {:?}", edits);
3653        drop(snapshot);
3654
3655        self.edit(edits, None, cx);
3656    }
3657
3658    pub fn randomly_edit_excerpts(
3659        &mut self,
3660        rng: &mut impl rand::Rng,
3661        mutation_count: usize,
3662        cx: &mut Context<Self>,
3663    ) {
3664        use rand::prelude::*;
3665        use std::env;
3666        use util::RandomCharIter;
3667
3668        let max_excerpts = env::var("MAX_EXCERPTS")
3669            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3670            .unwrap_or(5);
3671
3672        let mut buffers = Vec::new();
3673        for _ in 0..mutation_count {
3674            if rng.random_bool(0.05) {
3675                log::info!("Clearing multi-buffer");
3676                self.clear(cx);
3677                continue;
3678            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3679                let ids = self.excerpt_ids();
3680                let mut excerpts = HashSet::default();
3681                for _ in 0..rng.random_range(0..ids.len()) {
3682                    excerpts.extend(ids.choose(rng).copied());
3683                }
3684
3685                let line_count = rng.random_range(0..5);
3686
3687                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3688
3689                self.expand_excerpts(
3690                    excerpts.iter().cloned(),
3691                    line_count,
3692                    ExpandExcerptDirection::UpAndDown,
3693                    cx,
3694                );
3695                continue;
3696            }
3697
3698            let excerpt_ids = self.excerpt_ids();
3699            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3700                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3701                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3702                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3703                    let buffer = buffers.last().unwrap().read(cx);
3704                    log::info!(
3705                        "Creating new buffer {} with text: {:?}",
3706                        buffer.remote_id(),
3707                        buffer.text()
3708                    );
3709                    buffers.last().unwrap().clone()
3710                } else {
3711                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3712                };
3713
3714                let buffer = buffer_handle.read(cx);
3715                let buffer_text = buffer.text();
3716                let ranges = (0..rng.random_range(0..5))
3717                    .map(|_| {
3718                        let end_ix =
3719                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3720                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3721                        ExcerptRange::new(start_ix..end_ix)
3722                    })
3723                    .collect::<Vec<_>>();
3724                log::info!(
3725                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3726                    buffer_handle.read(cx).remote_id(),
3727                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3728                    ranges
3729                        .iter()
3730                        .map(|r| &buffer_text[r.context.clone()])
3731                        .collect::<Vec<_>>()
3732                );
3733
3734                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3735                log::info!("Inserted with ids: {:?}", excerpt_id);
3736            } else {
3737                let remove_count = rng.random_range(1..=excerpt_ids.len());
3738                let mut excerpts_to_remove = excerpt_ids
3739                    .choose_multiple(rng, remove_count)
3740                    .cloned()
3741                    .collect::<Vec<_>>();
3742                let snapshot = self.snapshot.borrow();
3743                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3744                drop(snapshot);
3745                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3746                self.remove_excerpts(excerpts_to_remove, cx);
3747            }
3748        }
3749    }
3750
3751    pub fn randomly_mutate(
3752        &mut self,
3753        rng: &mut impl rand::Rng,
3754        mutation_count: usize,
3755        cx: &mut Context<Self>,
3756    ) {
3757        use rand::prelude::*;
3758
3759        if rng.random_bool(0.7) || self.singleton {
3760            let buffer = self
3761                .buffers
3762                .values()
3763                .choose(rng)
3764                .map(|state| state.buffer.clone());
3765
3766            if let Some(buffer) = buffer {
3767                buffer.update(cx, |buffer, cx| {
3768                    if rng.random() {
3769                        buffer.randomly_edit(rng, mutation_count, cx);
3770                    } else {
3771                        buffer.randomly_undo_redo(rng, cx);
3772                    }
3773                });
3774            } else {
3775                self.randomly_edit(rng, mutation_count, cx);
3776            }
3777        } else {
3778            self.randomly_edit_excerpts(rng, mutation_count, cx);
3779        }
3780
3781        self.check_invariants(cx);
3782    }
3783
3784    fn check_invariants(&self, cx: &App) {
3785        self.read(cx).check_invariants();
3786    }
3787}
3788
3789impl EventEmitter<Event> for MultiBuffer {}
3790
3791impl MultiBufferSnapshot {
3792    pub fn text(&self) -> String {
3793        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3794            .map(|chunk| chunk.text)
3795            .collect()
3796    }
3797
3798    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3799        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3800            .flat_map(|c| c.chars().rev())
3801    }
3802
3803    fn reversed_chunks_in_range(
3804        &self,
3805        range: Range<MultiBufferOffset>,
3806    ) -> ReversedMultiBufferChunks<'_> {
3807        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3808        cursor.seek(&range.end);
3809        let current_chunks = cursor.region().as_ref().map(|region| {
3810            let start_overshoot = range.start.saturating_sub(region.range.start);
3811            let end_overshoot = range.end - region.range.start;
3812            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3813            let start = region.buffer_range.start + start_overshoot;
3814            region.buffer.reversed_chunks_in_range(start..end)
3815        });
3816        ReversedMultiBufferChunks {
3817            cursor,
3818            current_chunks,
3819            start: range.start,
3820            offset: range.end,
3821        }
3822    }
3823
3824    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3825        let offset = position.to_offset(self);
3826        self.text_for_range(offset..self.len())
3827            .flat_map(|chunk| chunk.chars())
3828    }
3829
3830    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3831        self.chunks(range, false).map(|chunk| chunk.text)
3832    }
3833
3834    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3835        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3836            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3837    }
3838
3839    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3840    where
3841        T: ToOffset,
3842    {
3843        let position = position.to_offset(self);
3844        position == self.clip_offset(position, Bias::Left)
3845            && self
3846                .bytes_in_range(position..self.len())
3847                .flatten()
3848                .copied()
3849                .take(needle.len())
3850                .eq(needle.bytes())
3851    }
3852
3853    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3854        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3855    }
3856
3857    pub fn diff_hunks_in_range<T: ToPoint>(
3858        &self,
3859        range: Range<T>,
3860    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3861        let query_range = range.start.to_point(self)..range.end.to_point(self);
3862        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3863            let diff = self.diffs.get(&buffer.remote_id())?;
3864            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3865                if diff.is_inverted {
3866                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3867                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3868                    Box::new(
3869                        diff.hunks_intersecting_base_text_range(
3870                            buffer_start..buffer_end,
3871                            diff.original_buffer_snapshot(),
3872                        )
3873                        .map(move |hunk| (hunk, buffer, true)),
3874                    )
3875                } else {
3876                    let buffer_start = buffer.anchor_before(buffer_range.start);
3877                    let buffer_end = buffer.anchor_after(buffer_range.end);
3878                    Box::new(
3879                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3880                            .map(move |hunk| (hunk, buffer, false)),
3881                    )
3882                };
3883            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3884                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3885                    return None;
3886                }
3887                let range = if is_inverted {
3888                    hunk.diff_base_byte_range.to_point(&buffer)
3889                } else {
3890                    hunk.range.clone()
3891                };
3892                Some((range, (hunk, is_inverted)))
3893            }))
3894        })
3895        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3896            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3897            {
3898                return None;
3899            }
3900            let end_row = if range.end.column == 0 {
3901                range.end.row
3902            } else {
3903                range.end.row + 1
3904            };
3905
3906            let word_diffs =
3907                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3908                    .then(|| {
3909                        let mut word_diffs = Vec::new();
3910
3911                        if self.show_deleted_hunks || is_inverted {
3912                            let hunk_start_offset = if is_inverted {
3913                                Anchor::in_buffer(
3914                                    excerpt.id,
3915                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3916                                )
3917                                .to_offset(self)
3918                            } else {
3919                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3920                                    .to_offset(self)
3921                            };
3922
3923                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3924                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3925                            }));
3926                        }
3927
3928                        if !is_inverted {
3929                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3930                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3931                            }));
3932                        }
3933                        word_diffs
3934                    })
3935                    .unwrap_or_default();
3936
3937            let staged_rows = (!hunk.buffer_staged_lines.is_empty())
3938                .then(|| {
3939                    let mut rows = Vec::new();
3940                    for range in &hunk.buffer_staged_lines {
3941                        let range =
3942                            Anchor::range_in_buffer(excerpt.id, range.clone()).to_point(self);
3943                        rows.extend((range.start.row..range.end.row).map(MultiBufferRow));
3944                    }
3945                    rows
3946                })
3947                .unwrap_or_default();
3948
3949            let buffer_range = if is_inverted {
3950                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3951                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3952            } else {
3953                hunk.buffer_range.clone()
3954            };
3955            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3956                DiffHunkStatusKind::Deleted
3957            } else if hunk.diff_base_byte_range.is_empty() {
3958                DiffHunkStatusKind::Added
3959            } else {
3960                DiffHunkStatusKind::Modified
3961            };
3962            Some(MultiBufferDiffHunk {
3963                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3964                buffer_id: excerpt.buffer_id,
3965                excerpt_id: excerpt.id,
3966                buffer_range,
3967                word_diffs,
3968                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3969                    ..BufferOffset(hunk.diff_base_byte_range.end),
3970                status: DiffHunkStatus {
3971                    kind: status_kind,
3972                    secondary: hunk.secondary_status,
3973                },
3974                staged_rows,
3975            })
3976        })
3977    }
3978
3979    fn excerpts_for_range<T: ToOffset>(
3980        &self,
3981        range: Range<T>,
3982    ) -> impl Iterator<Item = &Excerpt> + '_ {
3983        let range = range.start.to_offset(self)..range.end.to_offset(self);
3984        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3985        cursor.seek(&range.start);
3986        std::iter::from_fn(move || {
3987            let region = cursor.region()?;
3988            if region.range.start > range.end
3989                || region.range.start == range.end && region.range.start > range.start
3990            {
3991                return None;
3992            }
3993            let excerpt = region.excerpt;
3994            cursor.next_excerpt();
3995            Some(excerpt)
3996        })
3997    }
3998
3999    pub fn excerpt_ids_for_range<T: ToOffset>(
4000        &self,
4001        range: Range<T>,
4002    ) -> impl Iterator<Item = ExcerptId> + '_ {
4003        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4004    }
4005
4006    pub fn buffer_ids_for_range<T: ToOffset>(
4007        &self,
4008        range: Range<T>,
4009    ) -> impl Iterator<Item = BufferId> + '_ {
4010        self.excerpts_for_range(range)
4011            .map(|excerpt| excerpt.buffer_id)
4012    }
4013
4014    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4015        &self,
4016        ranges: impl Iterator<Item = Range<T>>,
4017    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4018        ranges.flat_map(|range| {
4019            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4020                .into_iter()
4021        })
4022    }
4023
4024    pub fn range_to_buffer_ranges<R, T>(
4025        &self,
4026        range: R,
4027    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4028    where
4029        R: RangeBounds<T>,
4030        T: ToOffset,
4031    {
4032        let start = match range.start_bound() {
4033            Bound::Included(start) => start.to_offset(self),
4034            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4035            Bound::Unbounded => MultiBufferOffset::ZERO,
4036        };
4037        let end_bound = match range.end_bound() {
4038            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4039            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4040            Bound::Unbounded => Bound::Unbounded,
4041        };
4042        let bounds = (Bound::Included(start), end_bound);
4043
4044        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4045        cursor.seek(&start);
4046
4047        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
4048        while let Some(region) = cursor.region() {
4049            let dominated_by_end_bound = match end_bound {
4050                Bound::Included(end) => region.range.start > end,
4051                Bound::Excluded(end) => region.range.start >= end,
4052                Bound::Unbounded => false,
4053            };
4054            if dominated_by_end_bound {
4055                break;
4056            }
4057            if region.is_main_buffer {
4058                let start_overshoot = start.saturating_sub(region.range.start);
4059                let end_offset = match end_bound {
4060                    Bound::Included(end) | Bound::Excluded(end) => end,
4061                    Bound::Unbounded => region.range.end,
4062                };
4063                let end_overshoot = end_offset.saturating_sub(region.range.start);
4064                let start = region
4065                    .buffer_range
4066                    .end
4067                    .min(region.buffer_range.start + start_overshoot);
4068                let end = region
4069                    .buffer_range
4070                    .end
4071                    .min(region.buffer_range.start + end_overshoot);
4072                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
4073                    *excerpt_id == region.excerpt.id && prev_range.end == start
4074                }) {
4075                    prev.1.end = end;
4076                } else {
4077                    result.push((region.buffer, start..end, region.excerpt.id));
4078                }
4079            }
4080            cursor.next();
4081        }
4082
4083        if let Some(excerpt) = cursor.excerpt() {
4084            let dominated_by_prev_excerpt =
4085                result.last().is_some_and(|(_, _, id)| *id == excerpt.id);
4086            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4087                let excerpt_position = self.len();
4088                if bounds.contains(&excerpt_position) {
4089                    let buffer_offset =
4090                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4091                    result.push((&excerpt.buffer, buffer_offset..buffer_offset, excerpt.id));
4092                }
4093            }
4094        }
4095
4096        result
4097    }
4098
4099    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4100        &self,
4101        range: Range<T>,
4102    ) -> impl Iterator<
4103        Item = (
4104            &BufferSnapshot,
4105            Range<BufferOffset>,
4106            ExcerptId,
4107            Option<Anchor>,
4108        ),
4109    > + '_ {
4110        let start = range.start.to_offset(self);
4111        let end = range.end.to_offset(self);
4112
4113        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4114        cursor.seek(&start);
4115
4116        std::iter::from_fn(move || {
4117            let region = cursor.region()?;
4118            if region.range.start > end {
4119                return None;
4120            }
4121            let start_overshoot = start.saturating_sub(region.range.start);
4122            let end_overshoot = end.saturating_sub(region.range.start);
4123            let start = region
4124                .buffer_range
4125                .end
4126                .min(region.buffer_range.start + start_overshoot);
4127            let end = region
4128                .buffer_range
4129                .end
4130                .min(region.buffer_range.start + end_overshoot);
4131
4132            let region_excerpt_id = region.excerpt.id;
4133            let deleted_hunk_anchor = if region.is_main_buffer {
4134                None
4135            } else {
4136                Some(self.anchor_before(region.range.start))
4137            };
4138            let result = (
4139                region.buffer,
4140                start..end,
4141                region_excerpt_id,
4142                deleted_hunk_anchor,
4143            );
4144            cursor.next();
4145            Some(result)
4146        })
4147    }
4148
4149    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4150    /// coordinates.
4151    ///
4152    /// The given callback will be called for every excerpt intersecting the given range. It will
4153    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4154    /// The callback should return an iterator of metadata items from that buffer, each paired
4155    /// with a buffer range.
4156    ///
4157    /// The returned iterator yields each of these metadata items, paired with its range in
4158    /// multi-buffer coordinates.
4159    fn lift_buffer_metadata<'a, MBD, M, I>(
4160        &'a self,
4161        query_range: Range<MBD>,
4162        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4163    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4164    where
4165        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4166        MBD: MultiBufferDimension
4167            + Ord
4168            + Sub<Output = MBD::TextDimension>
4169            + ops::Add<MBD::TextDimension, Output = MBD>
4170            + ops::AddAssign<MBD::TextDimension>,
4171        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4172            + ops::Add<Output = MBD::TextDimension>
4173            + AddAssign<MBD::TextDimension>
4174            + Ord,
4175    {
4176        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4177        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4178
4179        // Find the excerpt and buffer offset where the given range ends.
4180        cursor.seek(&query_range.end);
4181        let mut range_end = None;
4182        while let Some(region) = cursor.region() {
4183            if region.is_main_buffer {
4184                let mut buffer_end = region.buffer_range.start;
4185                let overshoot = if query_range.end > region.range.start {
4186                    query_range.end - region.range.start
4187                } else {
4188                    <MBD::TextDimension>::default()
4189                };
4190                buffer_end = buffer_end + overshoot;
4191                range_end = Some((region.excerpt.id, buffer_end));
4192                break;
4193            }
4194            cursor.next();
4195        }
4196
4197        cursor.seek(&query_range.start);
4198
4199        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4200            && region.range.start > MBD::default()
4201        {
4202            cursor.prev()
4203        } else if let Some(region) = cursor.region()
4204            && region.is_main_buffer
4205            && region.diff_hunk_status.is_some()
4206        {
4207            cursor.prev();
4208            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4209                cursor.next();
4210            }
4211        }
4212
4213        iter::from_fn(move || {
4214            loop {
4215                let excerpt = cursor.excerpt()?;
4216
4217                // If we have already retrieved metadata for this excerpt, continue to use it.
4218                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4219                    .as_mut()
4220                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4221                {
4222                    Some(metadata)
4223                }
4224                // Otherwise, compute the intersection of the input range with the excerpt's range,
4225                // and retrieve the metadata for the resulting range.
4226                else {
4227                    let region = cursor.region()?;
4228                    let mut buffer_start;
4229                    if region.is_main_buffer {
4230                        buffer_start = region.buffer_range.start;
4231                        if query_range.start > region.range.start {
4232                            let overshoot = query_range.start - region.range.start;
4233                            buffer_start = buffer_start + overshoot;
4234                        }
4235                        buffer_start = buffer_start.min(region.buffer_range.end);
4236                    } else {
4237                        buffer_start = cursor.main_buffer_position()?;
4238                    };
4239                    let mut buffer_end = excerpt
4240                        .range
4241                        .context
4242                        .end
4243                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4244                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4245                        && excerpt.id == end_excerpt_id
4246                    {
4247                        buffer_end = buffer_end.min(end_buffer_offset);
4248                    }
4249
4250                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4251                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4252                    })
4253                };
4254
4255                // Visit each metadata item.
4256                if let Some((metadata_buffer_range, metadata)) =
4257                    metadata_iter.and_then(Iterator::next)
4258                {
4259                    // Find the multibuffer regions that contain the start and end of
4260                    // the metadata item's range.
4261                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4262                        while let Some(region) = cursor.region() {
4263                            if (region.is_main_buffer
4264                                && (region.buffer_range.end >= metadata_buffer_range.start
4265                                    || cursor.is_at_end_of_excerpt()))
4266                                || (!region.is_main_buffer
4267                                    && region.buffer_range.start == metadata_buffer_range.start)
4268                            {
4269                                break;
4270                            }
4271                            cursor.next();
4272                        }
4273                    }
4274                    let start_region = cursor.region()?.clone();
4275                    while let Some(region) = cursor.region() {
4276                        if region.is_main_buffer
4277                            && (region.buffer_range.end > metadata_buffer_range.end
4278                                || cursor.is_at_end_of_excerpt())
4279                        {
4280                            break;
4281                        }
4282                        cursor.next();
4283                    }
4284                    let end_region = cursor.region();
4285
4286                    // Convert the metadata item's range into multibuffer coordinates.
4287                    let mut start_position = start_region.range.start;
4288                    let region_buffer_start = start_region.buffer_range.start;
4289                    if start_region.is_main_buffer
4290                        && metadata_buffer_range.start > region_buffer_start
4291                    {
4292                        start_position =
4293                            start_position + (metadata_buffer_range.start - region_buffer_start);
4294                        start_position = start_position.min(start_region.range.end);
4295                    }
4296
4297                    let mut end_position = self.max_position();
4298                    if let Some(end_region) = &end_region {
4299                        end_position = end_region.range.start;
4300                        debug_assert!(end_region.is_main_buffer);
4301                        let region_buffer_start = end_region.buffer_range.start;
4302                        if metadata_buffer_range.end > region_buffer_start {
4303                            end_position =
4304                                end_position + (metadata_buffer_range.end - region_buffer_start);
4305                        }
4306                        end_position = end_position.min(end_region.range.end);
4307                    }
4308
4309                    if start_position <= query_range.end && end_position >= query_range.start {
4310                        return Some((start_position..end_position, metadata, excerpt));
4311                    }
4312                }
4313                // When there are no more metadata items for this excerpt, move to the next excerpt.
4314                else {
4315                    current_excerpt_metadata.take();
4316                    if let Some((end_excerpt_id, _)) = range_end
4317                        && excerpt.id == end_excerpt_id
4318                    {
4319                        return None;
4320                    }
4321                    cursor.next_excerpt();
4322                }
4323            }
4324        })
4325    }
4326
4327    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4328        let offset = position.to_offset(self);
4329
4330        let mut cursor = self
4331            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4332            );
4333        cursor.seek(&DimensionPair {
4334            key: offset,
4335            value: None,
4336        });
4337        cursor.seek_to_start_of_current_excerpt();
4338        let excerpt = cursor.excerpt()?;
4339
4340        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4341        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4342        let current_position = self
4343            .anchor_before(offset)
4344            .text_anchor
4345            .to_offset(&excerpt.buffer);
4346
4347        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4348            if diff.is_inverted {
4349                for hunk in diff.hunks_intersecting_base_text_range_rev(
4350                    excerpt_start..excerpt_end,
4351                    diff.original_buffer_snapshot(),
4352                ) {
4353                    if hunk.diff_base_byte_range.end >= current_position {
4354                        continue;
4355                    }
4356                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4357                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4358                    return Some(MultiBufferRow(start.row));
4359                }
4360            } else {
4361                let excerpt_end = excerpt
4362                    .buffer
4363                    .anchor_before(excerpt_end.min(current_position));
4364                for hunk in diff.hunks_intersecting_range_rev(
4365                    excerpt.range.context.start..excerpt_end,
4366                    &excerpt.buffer,
4367                ) {
4368                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4369                    if hunk_end >= current_position {
4370                        continue;
4371                    }
4372                    let start =
4373                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4374                    return Some(MultiBufferRow(start.row));
4375                }
4376            }
4377        }
4378
4379        loop {
4380            cursor.prev_excerpt();
4381            let excerpt = cursor.excerpt()?;
4382
4383            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4384                continue;
4385            };
4386            if diff.is_inverted {
4387                let Some(hunk) = diff
4388                    .hunks_intersecting_base_text_range_rev(
4389                        excerpt.range.context.to_offset(&excerpt.buffer),
4390                        diff.original_buffer_snapshot(),
4391                    )
4392                    .next()
4393                else {
4394                    continue;
4395                };
4396                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4397                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4398                return Some(MultiBufferRow(start.row));
4399            } else {
4400                let Some(hunk) = diff
4401                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4402                    .next()
4403                else {
4404                    continue;
4405                };
4406                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4407                return Some(MultiBufferRow(start.row));
4408            }
4409        }
4410    }
4411
4412    pub fn has_diff_hunks(&self) -> bool {
4413        self.diffs.values().any(|diff| !diff.is_empty())
4414    }
4415
4416    pub fn is_inside_word<T: ToOffset>(
4417        &self,
4418        position: T,
4419        scope_context: Option<CharScopeContext>,
4420    ) -> bool {
4421        let position = position.to_offset(self);
4422        let classifier = self
4423            .char_classifier_at(position)
4424            .scope_context(scope_context);
4425        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4426        let prev_char_kind = self
4427            .reversed_chars_at(position)
4428            .next()
4429            .map(|c| classifier.kind(c));
4430        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4431    }
4432
4433    pub fn surrounding_word<T: ToOffset>(
4434        &self,
4435        start: T,
4436        scope_context: Option<CharScopeContext>,
4437    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4438        let mut start = start.to_offset(self);
4439        let mut end = start;
4440        let mut next_chars = self.chars_at(start).peekable();
4441        let mut prev_chars = self.reversed_chars_at(start).peekable();
4442
4443        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4444
4445        let word_kind = cmp::max(
4446            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4447            next_chars.peek().copied().map(|c| classifier.kind(c)),
4448        );
4449
4450        for ch in prev_chars {
4451            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4452                start -= ch.len_utf8();
4453            } else {
4454                break;
4455            }
4456        }
4457
4458        for ch in next_chars {
4459            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4460                end += ch.len_utf8();
4461            } else {
4462                break;
4463            }
4464        }
4465
4466        (start..end, word_kind)
4467    }
4468
4469    pub fn char_kind_before<T: ToOffset>(
4470        &self,
4471        start: T,
4472        scope_context: Option<CharScopeContext>,
4473    ) -> Option<CharKind> {
4474        let start = start.to_offset(self);
4475        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4476        self.reversed_chars_at(start)
4477            .next()
4478            .map(|ch| classifier.kind(ch))
4479    }
4480
4481    pub fn is_singleton(&self) -> bool {
4482        self.singleton
4483    }
4484
4485    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4486        if self.singleton {
4487            self.excerpts
4488                .iter()
4489                .next()
4490                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4491        } else {
4492            None
4493        }
4494    }
4495
4496    pub fn len(&self) -> MultiBufferOffset {
4497        self.diff_transforms.summary().output.len
4498    }
4499
4500    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4501        MBD::from_summary(&self.text_summary())
4502    }
4503
4504    pub fn is_empty(&self) -> bool {
4505        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4506    }
4507
4508    pub fn widest_line_number(&self) -> u32 {
4509        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4510        self.excerpts.summary().widest_line_number + 1
4511    }
4512
4513    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4514        let range = range.start.to_offset(self)..range.end.to_offset(self);
4515        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4516        excerpts.seek(&range.start);
4517
4518        let mut chunk;
4519        let mut has_trailing_newline;
4520        let excerpt_bytes;
4521        if let Some(region) = excerpts.region() {
4522            let mut bytes = region.buffer.bytes_in_range(
4523                region.buffer_range.start + (range.start - region.range.start)
4524                    ..(region.buffer_range.start + (range.end - region.range.start))
4525                        .min(region.buffer_range.end),
4526            );
4527            chunk = bytes.next().unwrap_or(&[][..]);
4528            excerpt_bytes = Some(bytes);
4529            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4530            if chunk.is_empty() && has_trailing_newline {
4531                chunk = b"\n";
4532                has_trailing_newline = false;
4533            }
4534        } else {
4535            chunk = &[][..];
4536            excerpt_bytes = None;
4537            has_trailing_newline = false;
4538        };
4539
4540        MultiBufferBytes {
4541            range,
4542            cursor: excerpts,
4543            excerpt_bytes,
4544            has_trailing_newline,
4545            chunk,
4546        }
4547    }
4548
4549    pub fn reversed_bytes_in_range<T: ToOffset>(
4550        &self,
4551        range: Range<T>,
4552    ) -> ReversedMultiBufferBytes<'_> {
4553        let range = range.start.to_offset(self)..range.end.to_offset(self);
4554        let mut chunks = self.reversed_chunks_in_range(range.clone());
4555        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4556        ReversedMultiBufferBytes {
4557            range,
4558            chunks,
4559            chunk,
4560        }
4561    }
4562
4563    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4564        let mut cursor = self.cursor::<Point, Point>();
4565        cursor.seek(&Point::new(start_row.0, 0));
4566        let mut result = MultiBufferRows {
4567            point: Point::new(0, 0),
4568            is_empty: self.excerpts.is_empty(),
4569            is_singleton: self.is_singleton(),
4570            cursor,
4571        };
4572        result.seek(start_row);
4573        result
4574    }
4575
4576    pub fn chunks<T: ToOffset>(
4577        &self,
4578        range: Range<T>,
4579        language_aware: bool,
4580    ) -> MultiBufferChunks<'_> {
4581        let mut chunks = MultiBufferChunks {
4582            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4583                ..ExcerptDimension(MultiBufferOffset::ZERO),
4584            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4585            excerpts: self.excerpts.cursor(()),
4586            diff_transforms: self.diff_transforms.cursor(()),
4587            diffs: &self.diffs,
4588            diff_base_chunks: None,
4589            excerpt_chunks: None,
4590            buffer_chunk: None,
4591            language_aware,
4592        };
4593        let range = range.start.to_offset(self)..range.end.to_offset(self);
4594        chunks.seek(range);
4595        chunks
4596    }
4597
4598    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4599        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4600    }
4601
4602    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4603        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4604    }
4605
4606    pub fn clip_offset_utf16(
4607        &self,
4608        offset: MultiBufferOffsetUtf16,
4609        bias: Bias,
4610    ) -> MultiBufferOffsetUtf16 {
4611        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4612    }
4613
4614    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4615        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4616            buffer.clip_point_utf16(Unclipped(point), bias)
4617        })
4618    }
4619
4620    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4621        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4622    }
4623
4624    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4625        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4626    }
4627
4628    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4629        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4630    }
4631
4632    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4633        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4634    }
4635
4636    #[instrument(skip_all)]
4637    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4638        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4639    }
4640
4641    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4642        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4643    }
4644
4645    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4646        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4647    }
4648
4649    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4650        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4651    }
4652
4653    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4654        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4655    }
4656
4657    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4658        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4659    }
4660
4661    fn clip_dimension<MBD, BD>(
4662        &self,
4663        position: MBD,
4664        bias: Bias,
4665        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4666    ) -> MBD
4667    where
4668        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4669        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4670    {
4671        let mut cursor = self.cursor::<MBD, BD>();
4672        cursor.seek(&position);
4673        if let Some(region) = cursor.region() {
4674            if position >= region.range.end {
4675                return region.range.end;
4676            }
4677            let overshoot = position - region.range.start;
4678            let mut buffer_position = region.buffer_range.start;
4679            buffer_position += overshoot;
4680            let clipped_buffer_position =
4681                clip_buffer_position(region.buffer, buffer_position, bias);
4682            let mut position = region.range.start;
4683            position += clipped_buffer_position - region.buffer_range.start;
4684            position
4685        } else {
4686            self.max_position()
4687        }
4688    }
4689
4690    #[instrument(skip_all)]
4691    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4692        &self,
4693        key: MBR1,
4694        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4695    ) -> MBR2
4696    where
4697        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4698        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4699        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4700        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4701    {
4702        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4703        cursor.seek(&DimensionPair { key, value: None });
4704        if let Some(region) = cursor.region() {
4705            if key >= region.range.end.key {
4706                return region.range.end.value.unwrap();
4707            }
4708            let start_key = region.range.start.key;
4709            let start_value = region.range.start.value.unwrap();
4710            let buffer_start_key = region.buffer_range.start.key;
4711            let buffer_start_value = region.buffer_range.start.value.unwrap();
4712            let mut buffer_key = buffer_start_key;
4713            buffer_key += key - start_key;
4714            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4715            let mut result = start_value;
4716            result += buffer_value - buffer_start_value;
4717            result
4718        } else {
4719            self.max_position()
4720        }
4721    }
4722
4723    pub fn point_to_buffer_offset<T: ToOffset>(
4724        &self,
4725        point: T,
4726    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4727        let offset = point.to_offset(self);
4728        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4729        cursor.seek(&offset);
4730        let region = cursor.region()?;
4731        let overshoot = offset - region.range.start;
4732        let buffer_offset = region.buffer_range.start + overshoot;
4733        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4734            && region.has_trailing_newline
4735            && !region.is_main_buffer
4736        {
4737            let main_buffer_position = cursor.main_buffer_position()?;
4738            let buffer_snapshot = &cursor.excerpt()?.buffer;
4739            return Some((buffer_snapshot, main_buffer_position));
4740        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4741            return None;
4742        }
4743        Some((region.buffer, buffer_offset))
4744    }
4745
4746    pub fn point_to_buffer_point(
4747        &self,
4748        point: Point,
4749    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4750        let mut cursor = self.cursor::<Point, Point>();
4751        cursor.seek(&point);
4752        let region = cursor.region()?;
4753        let overshoot = point - region.range.start;
4754        let buffer_point = region.buffer_range.start + overshoot;
4755        let excerpt = cursor.excerpt()?;
4756        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4757            && region.has_trailing_newline
4758            && !region.is_main_buffer
4759        {
4760            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4761        } else if buffer_point > region.buffer.max_point() {
4762            return None;
4763        }
4764        Some((region.buffer, buffer_point, excerpt.id))
4765    }
4766
4767    pub fn suggested_indents(
4768        &self,
4769        rows: impl IntoIterator<Item = u32>,
4770        cx: &App,
4771    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4772        let mut result = BTreeMap::new();
4773        self.suggested_indents_callback(
4774            rows,
4775            |row, indent| {
4776                result.insert(row, indent);
4777                ControlFlow::Continue(())
4778            },
4779            cx,
4780        );
4781        result
4782    }
4783
4784    // move this to be a generator once those are a thing
4785    pub fn suggested_indents_callback(
4786        &self,
4787        rows: impl IntoIterator<Item = u32>,
4788        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4789        cx: &App,
4790    ) {
4791        let mut rows_for_excerpt = Vec::new();
4792        let mut cursor = self.cursor::<Point, Point>();
4793        let mut rows = rows.into_iter().peekable();
4794        let mut prev_row = u32::MAX;
4795        let mut prev_language_indent_size = IndentSize::default();
4796
4797        while let Some(row) = rows.next() {
4798            cursor.seek(&Point::new(row, 0));
4799            let Some(region) = cursor.region() else {
4800                continue;
4801            };
4802
4803            // Retrieve the language and indent size once for each disjoint region being indented.
4804            let single_indent_size = if row.saturating_sub(1) == prev_row {
4805                prev_language_indent_size
4806            } else {
4807                region
4808                    .buffer
4809                    .language_indent_size_at(Point::new(row, 0), cx)
4810            };
4811            prev_language_indent_size = single_indent_size;
4812            prev_row = row;
4813
4814            let start_buffer_row = region.buffer_range.start.row;
4815            let start_multibuffer_row = region.range.start.row;
4816            let end_multibuffer_row = region.range.end.row;
4817
4818            rows_for_excerpt.push(row);
4819            while let Some(next_row) = rows.peek().copied() {
4820                if end_multibuffer_row > next_row {
4821                    rows_for_excerpt.push(next_row);
4822                    rows.next();
4823                } else {
4824                    break;
4825                }
4826            }
4827
4828            let buffer_rows = rows_for_excerpt
4829                .drain(..)
4830                .map(|row| start_buffer_row + row - start_multibuffer_row);
4831            let buffer_indents = region
4832                .buffer
4833                .suggested_indents(buffer_rows, single_indent_size);
4834            for (row, indent) in buffer_indents {
4835                if cb(
4836                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4837                    indent,
4838                )
4839                .is_break()
4840                {
4841                    return;
4842                }
4843            }
4844        }
4845    }
4846
4847    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4848        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4849            let mut size = buffer.indent_size_for_line(range.start.row);
4850            size.len = size
4851                .len
4852                .min(range.end.column)
4853                .saturating_sub(range.start.column);
4854            size
4855        } else {
4856            IndentSize::spaces(0)
4857        }
4858    }
4859
4860    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4861        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4862            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4863        } else {
4864            LineIndent::spaces(0)
4865        }
4866    }
4867
4868    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4869        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4870
4871        if self.language_settings(cx).extend_comment_on_newline
4872            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4873        {
4874            let delimiters = language_scope.line_comment_prefixes();
4875            for delimiter in delimiters {
4876                if *self
4877                    .chars_at(Point::new(row.0, indent.len() as u32))
4878                    .take(delimiter.chars().count())
4879                    .collect::<String>()
4880                    .as_str()
4881                    == **delimiter
4882                {
4883                    indent.push_str(delimiter);
4884                    break;
4885                }
4886            }
4887        }
4888
4889        indent
4890    }
4891
4892    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4893    where
4894        T: ToOffset,
4895    {
4896        for char in self.reversed_chars_at(position) {
4897            if !char.is_whitespace() {
4898                return false;
4899            }
4900            if char == '\n' {
4901                return true;
4902            }
4903        }
4904        true
4905    }
4906
4907    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4908        while row.0 > 0 {
4909            row.0 -= 1;
4910            if !self.is_line_blank(row) {
4911                return Some(row);
4912            }
4913        }
4914        None
4915    }
4916
4917    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4918        if let Some((_, range)) = self.buffer_line_for_row(row) {
4919            range.end.column - range.start.column
4920        } else {
4921            0
4922        }
4923    }
4924
4925    pub fn buffer_line_for_row(
4926        &self,
4927        row: MultiBufferRow,
4928    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4929        let mut cursor = self.cursor::<Point, Point>();
4930        let point = Point::new(row.0, 0);
4931        cursor.seek(&point);
4932        let region = cursor.region()?;
4933        let overshoot = point.min(region.range.end) - region.range.start;
4934        let buffer_point = region.buffer_range.start + overshoot;
4935        if buffer_point.row > region.buffer_range.end.row {
4936            return None;
4937        }
4938        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4939        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4940            .min(region.buffer_range.end);
4941        Some((region.buffer, line_start..line_end))
4942    }
4943
4944    pub fn max_point(&self) -> Point {
4945        self.text_summary().lines
4946    }
4947
4948    pub fn max_row(&self) -> MultiBufferRow {
4949        MultiBufferRow(self.text_summary().lines.row)
4950    }
4951
4952    pub fn text_summary(&self) -> MBTextSummary {
4953        self.diff_transforms.summary().output
4954    }
4955
4956    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4957    where
4958        MBD: MultiBufferDimension + AddAssign,
4959        O: ToOffset,
4960    {
4961        let range = range.start.to_offset(self)..range.end.to_offset(self);
4962        let mut cursor = self
4963            .diff_transforms
4964            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4965        cursor.seek(&range.start, Bias::Right);
4966
4967        let Some(first_transform) = cursor.item() else {
4968            return MBD::from_summary(&MBTextSummary::default());
4969        };
4970
4971        let diff_transform_start = cursor.start().0;
4972        let diff_transform_end = cursor.end().0;
4973        let diff_start = range.start;
4974        let start_overshoot = diff_start - diff_transform_start;
4975        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4976
4977        let mut result = match first_transform {
4978            DiffTransform::BufferContent { .. } => {
4979                let excerpt_start = cursor.start().1 + start_overshoot;
4980                let excerpt_end = cursor.start().1 + end_overshoot;
4981                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4982            }
4983            DiffTransform::DeletedHunk {
4984                buffer_id,
4985                base_text_byte_range,
4986                has_trailing_newline,
4987                ..
4988            } => {
4989                let buffer_start = base_text_byte_range.start + start_overshoot;
4990                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4991                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4992                    panic!("{:?} is in non-existent deleted hunk", range.start)
4993                };
4994
4995                let include_trailing_newline =
4996                    *has_trailing_newline && range.end >= diff_transform_end;
4997                if include_trailing_newline {
4998                    buffer_end -= 1;
4999                }
5000
5001                let mut summary = base_text
5002                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5003
5004                if include_trailing_newline {
5005                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5006                        &TextSummary::newline(),
5007                    ))
5008                }
5009
5010                let mut result = MBD::default();
5011                result.add_text_dim(&summary);
5012                result
5013            }
5014        };
5015        if range.end < diff_transform_end {
5016            return result;
5017        }
5018
5019        cursor.next();
5020        result.add_mb_text_summary(
5021            &cursor
5022                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5023                .0,
5024        );
5025
5026        let Some(last_transform) = cursor.item() else {
5027            return result;
5028        };
5029
5030        let overshoot = range.end - cursor.start().0;
5031        let suffix = match last_transform {
5032            DiffTransform::BufferContent { .. } => {
5033                let end = cursor.start().1 + overshoot;
5034                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5035            }
5036            DiffTransform::DeletedHunk {
5037                base_text_byte_range,
5038                buffer_id,
5039                has_trailing_newline,
5040                ..
5041            } => {
5042                let buffer_end = base_text_byte_range.start + overshoot;
5043                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5044                    panic!("{:?} is in non-existent deleted hunk", range.end)
5045                };
5046
5047                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5048                    base_text_byte_range.start..buffer_end,
5049                );
5050                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5051                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5052                        &TextSummary::from("\n"),
5053                    ))
5054                }
5055
5056                let mut result = MBD::default();
5057                result.add_text_dim(&suffix);
5058                result
5059            }
5060        };
5061
5062        result += suffix;
5063        result
5064    }
5065
5066    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5067    where
5068        MBD: MultiBufferDimension + AddAssign,
5069    {
5070        let mut summary = MBD::default();
5071        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5072        cursor.seek(&range.start, Bias::Right);
5073        if let Some(excerpt) = cursor.item() {
5074            let mut end_before_newline = cursor.end();
5075            if excerpt.has_trailing_newline {
5076                end_before_newline -= 1;
5077            }
5078
5079            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5080            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5081            let end_in_excerpt =
5082                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5083            summary.add_text_dim(
5084                &excerpt
5085                    .buffer
5086                    .text_summary_for_range::<MBD::TextDimension, _>(
5087                        start_in_excerpt..end_in_excerpt,
5088                    ),
5089            );
5090
5091            if range.end > end_before_newline {
5092                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5093            }
5094
5095            cursor.next();
5096        }
5097
5098        if range.end > *cursor.start() {
5099            summary += cursor
5100                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5101                .0;
5102            if let Some(excerpt) = cursor.item() {
5103                range.end = cmp::max(*cursor.start(), range.end);
5104
5105                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5106                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5107                summary.add_text_dim(
5108                    &excerpt
5109                        .buffer
5110                        .text_summary_for_range::<MBD::TextDimension, _>(
5111                            excerpt_start..end_in_excerpt,
5112                        ),
5113                );
5114            }
5115        }
5116
5117        summary
5118    }
5119
5120    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5121    where
5122        MBD: MultiBufferDimension
5123            + Ord
5124            + Sub<Output = MBD::TextDimension>
5125            + Sub<MBD::TextDimension, Output = MBD>
5126            + AddAssign<MBD::TextDimension>
5127            + Add<MBD::TextDimension, Output = MBD>,
5128        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5129    {
5130        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5131        let locator = self.excerpt_locator_for_id(excerpt_id);
5132        let (start, _, mut item) = self
5133            .excerpts
5134            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5135        let mut start = MBD::from_summary(&start.text);
5136        if item.is_none() && excerpt_id == ExcerptId::max() {
5137            item = self.excerpts.last();
5138            if let Some(last_summary) = self.excerpts.last_summary() {
5139                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5140            }
5141        }
5142
5143        if self.diff_transforms.is_empty() {
5144            let excerpt_start_position = ExcerptDimension(start);
5145            if let Some(excerpt) = item {
5146                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5147                    return excerpt_start_position.0;
5148                }
5149                let excerpt_buffer_start = excerpt
5150                    .range
5151                    .context
5152                    .start
5153                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5154                let excerpt_buffer_end = excerpt
5155                    .range
5156                    .context
5157                    .end
5158                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5159                let buffer_summary = anchor
5160                    .text_anchor
5161                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5162                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5163                let mut position = excerpt_start_position;
5164                if summary > excerpt_buffer_start {
5165                    position += summary - excerpt_buffer_start;
5166                }
5167
5168                position.0
5169            } else {
5170                excerpt_start_position.0
5171            }
5172        } else {
5173            let mut diff_transforms_cursor = self
5174                .diff_transforms
5175                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5176            diff_transforms_cursor.next();
5177
5178            let excerpt_start_position = ExcerptDimension(start);
5179            if let Some(excerpt) = item {
5180                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5181                    return self.resolve_summary_for_anchor(
5182                        &Anchor::min(),
5183                        excerpt_start_position,
5184                        &mut diff_transforms_cursor,
5185                    );
5186                }
5187                let excerpt_buffer_start = excerpt
5188                    .range
5189                    .context
5190                    .start
5191                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5192                let excerpt_buffer_end = excerpt
5193                    .range
5194                    .context
5195                    .end
5196                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5197                let buffer_summary = anchor
5198                    .text_anchor
5199                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5200                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5201                let mut position = excerpt_start_position;
5202                if summary > excerpt_buffer_start {
5203                    position += summary - excerpt_buffer_start;
5204                }
5205
5206                if diff_transforms_cursor.start().0 < position {
5207                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5208                }
5209                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5210            } else {
5211                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5212                self.resolve_summary_for_anchor(
5213                    &Anchor::max(),
5214                    excerpt_start_position,
5215                    &mut diff_transforms_cursor,
5216                )
5217            }
5218        }
5219    }
5220
5221    fn resolve_summary_for_anchor<MBD>(
5222        &self,
5223        anchor: &Anchor,
5224        excerpt_position: ExcerptDimension<MBD>,
5225        diff_transforms: &mut Cursor<
5226            DiffTransform,
5227            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5228        >,
5229    ) -> MBD
5230    where
5231        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5232    {
5233        loop {
5234            let transform_end_position = diff_transforms.end().0;
5235            let at_transform_end =
5236                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5237            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5238                diff_transforms.next();
5239                continue;
5240            }
5241
5242            let mut position = diff_transforms.start().1;
5243            match diff_transforms.item() {
5244                Some(DiffTransform::DeletedHunk {
5245                    buffer_id,
5246                    base_text_byte_range,
5247                    ..
5248                }) => {
5249                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5250                        && let Some(base_text) =
5251                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5252                        && diff_base_anchor.is_valid(&base_text)
5253                    {
5254                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5255                        if base_text_offset >= base_text_byte_range.start
5256                            && base_text_offset <= base_text_byte_range.end
5257                        {
5258                            let position_in_hunk = base_text
5259                                .text_summary_for_range::<MBD::TextDimension, _>(
5260                                    base_text_byte_range.start..base_text_offset,
5261                                );
5262                            position.0.add_text_dim(&position_in_hunk);
5263                        } else if at_transform_end {
5264                            diff_transforms.next();
5265                            continue;
5266                        }
5267                    }
5268                }
5269                _ => {
5270                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5271                        diff_transforms.next();
5272                        continue;
5273                    }
5274                    let overshoot = excerpt_position - diff_transforms.start().0;
5275                    position += overshoot;
5276                }
5277            }
5278
5279            return position.0;
5280        }
5281    }
5282
5283    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5284        let mut cursor = self
5285            .excerpts
5286            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5287        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5288
5289        cursor.seek(&Some(locator), Bias::Left);
5290        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5291            cursor.prev();
5292        }
5293
5294        let mut position = cursor.start().1;
5295        if let Some(excerpt) = cursor.item()
5296            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5297        {
5298            let excerpt_buffer_start = excerpt
5299                .buffer
5300                .offset_for_anchor(&excerpt.range.context.start);
5301            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5302            let buffer_position = cmp::min(
5303                excerpt_buffer_end,
5304                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5305            );
5306            if buffer_position > excerpt_buffer_start {
5307                position += buffer_position - excerpt_buffer_start;
5308            }
5309        }
5310        position
5311    }
5312
5313    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5314        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5315            excerpt_id = *replacement;
5316        }
5317        excerpt_id
5318    }
5319
5320    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5321    where
5322        MBD: MultiBufferDimension
5323            + Ord
5324            + Sub<Output = MBD::TextDimension>
5325            + AddAssign<MBD::TextDimension>,
5326        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5327        I: 'a + IntoIterator<Item = &'a Anchor>,
5328    {
5329        let mut anchors = anchors.into_iter().peekable();
5330        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5331        let mut diff_transforms_cursor = self
5332            .diff_transforms
5333            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5334        diff_transforms_cursor.next();
5335
5336        let mut summaries = Vec::new();
5337        while let Some(anchor) = anchors.peek() {
5338            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5339
5340            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5341                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5342            });
5343
5344            let locator = self.excerpt_locator_for_id(excerpt_id);
5345            cursor.seek_forward(locator, Bias::Left);
5346            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5347                cursor.prev();
5348            }
5349
5350            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5351            if let Some(excerpt) = cursor.item() {
5352                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5353                    let position = self.resolve_summary_for_anchor(
5354                        &Anchor::min(),
5355                        excerpt_start_position,
5356                        &mut diff_transforms_cursor,
5357                    );
5358                    summaries.extend(excerpt_anchors.map(|_| position));
5359                    continue;
5360                }
5361                let excerpt_buffer_start = excerpt
5362                    .range
5363                    .context
5364                    .start
5365                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5366                let excerpt_buffer_end = excerpt
5367                    .range
5368                    .context
5369                    .end
5370                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5371                for (buffer_summary, anchor) in excerpt
5372                    .buffer
5373                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5374                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5375                    )
5376                {
5377                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5378                    let mut position = excerpt_start_position;
5379                    if summary > excerpt_buffer_start {
5380                        position += summary - excerpt_buffer_start;
5381                    }
5382
5383                    if diff_transforms_cursor.start().0 < position {
5384                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5385                    }
5386
5387                    summaries.push(self.resolve_summary_for_anchor(
5388                        anchor,
5389                        position,
5390                        &mut diff_transforms_cursor,
5391                    ));
5392                }
5393            } else {
5394                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5395                let position = self.resolve_summary_for_anchor(
5396                    &Anchor::max(),
5397                    excerpt_start_position,
5398                    &mut diff_transforms_cursor,
5399                );
5400                summaries.extend(excerpt_anchors.map(|_| position));
5401            }
5402        }
5403
5404        summaries
5405    }
5406
5407    pub fn dimensions_from_points<'a, MBD>(
5408        &'a self,
5409        points: impl 'a + IntoIterator<Item = Point>,
5410    ) -> impl 'a + Iterator<Item = MBD>
5411    where
5412        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5413    {
5414        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5415        cursor.seek(&DimensionPair {
5416            key: Point::default(),
5417            value: None,
5418        });
5419        let mut points = points.into_iter();
5420        iter::from_fn(move || {
5421            let point = points.next()?;
5422
5423            cursor.seek_forward(&DimensionPair {
5424                key: point,
5425                value: None,
5426            });
5427
5428            if let Some(region) = cursor.region() {
5429                let overshoot = point - region.range.start.key;
5430                let buffer_point = region.buffer_range.start + overshoot;
5431                let mut position = region.range.start.value.unwrap();
5432                position.add_text_dim(
5433                    &region
5434                        .buffer
5435                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5436                );
5437                if point == region.range.end.key && region.has_trailing_newline {
5438                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5439                }
5440                Some(position)
5441            } else {
5442                Some(MBD::from_summary(&self.text_summary()))
5443            }
5444        })
5445    }
5446
5447    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5448    where
5449        I: 'a + IntoIterator<Item = &'a Anchor>,
5450    {
5451        let mut anchors = anchors.into_iter().enumerate().peekable();
5452        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5453        cursor.next();
5454
5455        let mut result = Vec::new();
5456
5457        while let Some((_, anchor)) = anchors.peek() {
5458            let old_excerpt_id = anchor.excerpt_id;
5459
5460            // Find the location where this anchor's excerpt should be.
5461            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5462            cursor.seek_forward(&Some(old_locator), Bias::Left);
5463
5464            let next_excerpt = cursor.item();
5465            let prev_excerpt = cursor.prev_item();
5466
5467            // Process all of the anchors for this excerpt.
5468            while let Some((anchor_ix, &anchor)) =
5469                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5470            {
5471                let mut anchor = anchor;
5472
5473                // Leave min and max anchors unchanged if invalid or
5474                // if the old excerpt still exists at this location
5475                let mut kept_position = next_excerpt
5476                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5477                    || old_excerpt_id == ExcerptId::max()
5478                    || old_excerpt_id == ExcerptId::min();
5479
5480                // If the old excerpt no longer exists at this location, then attempt to
5481                // find an equivalent position for this anchor in an adjacent excerpt.
5482                if !kept_position {
5483                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5484                        if excerpt.contains(&anchor) {
5485                            anchor.excerpt_id = excerpt.id;
5486                            kept_position = true;
5487                            break;
5488                        }
5489                    }
5490                }
5491
5492                // If there's no adjacent excerpt that contains the anchor's position,
5493                // then report that the anchor has lost its position.
5494                if !kept_position {
5495                    anchor = if let Some(excerpt) = next_excerpt {
5496                        let mut text_anchor = excerpt
5497                            .range
5498                            .context
5499                            .start
5500                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5501                        if text_anchor
5502                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5503                            .is_gt()
5504                        {
5505                            text_anchor = excerpt.range.context.end;
5506                        }
5507                        Anchor::in_buffer(excerpt.id, text_anchor)
5508                    } else if let Some(excerpt) = prev_excerpt {
5509                        let mut text_anchor = excerpt
5510                            .range
5511                            .context
5512                            .end
5513                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5514                        if text_anchor
5515                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5516                            .is_lt()
5517                        {
5518                            text_anchor = excerpt.range.context.start;
5519                        }
5520                        Anchor::in_buffer(excerpt.id, text_anchor)
5521                    } else if anchor.text_anchor.bias == Bias::Left {
5522                        Anchor::min()
5523                    } else {
5524                        Anchor::max()
5525                    };
5526                }
5527
5528                result.push((anchor_ix, anchor, kept_position));
5529            }
5530        }
5531        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5532        result
5533    }
5534
5535    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5536        self.anchor_at(position, Bias::Left)
5537    }
5538
5539    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5540        self.anchor_at(position, Bias::Right)
5541    }
5542
5543    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5544        let offset = position.to_offset(self);
5545
5546        // Find the given position in the diff transforms. Determine the corresponding
5547        // offset in the excerpts, and whether the position is within a deleted hunk.
5548        let mut diff_transforms = self
5549            .diff_transforms
5550            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5551        diff_transforms.seek(&offset, Bias::Right);
5552
5553        if offset == diff_transforms.start().0
5554            && bias == Bias::Left
5555            && let Some(prev_item) = diff_transforms.prev_item()
5556            && let DiffTransform::DeletedHunk { .. } = prev_item
5557        {
5558            diff_transforms.prev();
5559        }
5560        let offset_in_transform = offset - diff_transforms.start().0;
5561        let mut excerpt_offset = diff_transforms.start().1;
5562        let mut diff_base_anchor = None;
5563        if let Some(DiffTransform::DeletedHunk {
5564            buffer_id,
5565            base_text_byte_range,
5566            has_trailing_newline,
5567            ..
5568        }) = diff_transforms.item()
5569        {
5570            let diff = self.diffs.get(buffer_id).expect("missing diff");
5571            if offset_in_transform > base_text_byte_range.len() {
5572                debug_assert!(*has_trailing_newline);
5573                bias = Bias::Right;
5574            } else {
5575                diff_base_anchor = Some(
5576                    diff.base_text()
5577                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5578                );
5579                bias = Bias::Left;
5580            }
5581        } else {
5582            excerpt_offset += MultiBufferOffset(offset_in_transform);
5583        };
5584
5585        let mut excerpts = self
5586            .excerpts
5587            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5588        excerpts.seek(&excerpt_offset, Bias::Right);
5589        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5590            excerpts.prev();
5591        }
5592        if let Some(excerpt) = excerpts.item() {
5593            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5594            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5595                overshoot -= 1;
5596                bias = Bias::Right;
5597            }
5598
5599            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5600            let text_anchor =
5601                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5602            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5603            match diff_base_anchor {
5604                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5605                None => anchor,
5606            }
5607        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5608        {
5609            Anchor::min()
5610        } else {
5611            Anchor::max()
5612        }
5613    }
5614
5615    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5616    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5617        let (excerpt, buffer, _) = self.as_singleton()?;
5618        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5619            Some(Anchor::in_buffer(*excerpt, text_anchor))
5620        } else {
5621            None
5622        }
5623    }
5624
5625    /// Returns an anchor for the given excerpt and text anchor,
5626    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5627    pub fn anchor_range_in_excerpt(
5628        &self,
5629        excerpt_id: ExcerptId,
5630        text_anchor: Range<text::Anchor>,
5631    ) -> Option<Range<Anchor>> {
5632        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5633
5634        Some(
5635            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5636                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5637        )
5638    }
5639
5640    /// Returns an anchor for the given excerpt and text anchor,
5641    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5642    pub fn anchor_in_excerpt(
5643        &self,
5644        excerpt_id: ExcerptId,
5645        text_anchor: text::Anchor,
5646    ) -> Option<Anchor> {
5647        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5648        Self::anchor_in_excerpt_(excerpt, text_anchor)
5649    }
5650
5651    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5652    pub fn anchors_in_excerpt(
5653        &self,
5654        excerpt_id: ExcerptId,
5655        text_anchors: impl IntoIterator<Item = text::Anchor>,
5656    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5657        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5658        Some(
5659            text_anchors
5660                .into_iter()
5661                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5662        )
5663    }
5664
5665    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5666        match text_anchor.buffer_id {
5667            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5668            Some(_) => return None,
5669            None if text_anchor.is_max() || text_anchor.is_min() => {
5670                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5671            }
5672            None => return None,
5673        }
5674
5675        let context = &excerpt.range.context;
5676        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5677            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5678        {
5679            return None;
5680        }
5681
5682        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5683    }
5684
5685    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5686        Some(self.excerpt(excerpt_id)?.range.context.clone())
5687    }
5688
5689    pub fn excerpt_range_for_excerpt(
5690        &self,
5691        excerpt_id: ExcerptId,
5692    ) -> Option<ExcerptRange<text::Anchor>> {
5693        Some(self.excerpt(excerpt_id)?.range.clone())
5694    }
5695
5696    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5697        if anchor.is_min() || anchor.is_max() {
5698            // todo(lw): should be `!self.is_empty()`
5699            true
5700        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5701            excerpt.buffer.can_resolve(&anchor.text_anchor)
5702        } else {
5703            false
5704        }
5705    }
5706
5707    pub fn excerpts(
5708        &self,
5709    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5710        self.excerpts
5711            .iter()
5712            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5713    }
5714
5715    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5716    where
5717        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5718        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5719    {
5720        let excerpts = self.excerpts.cursor(());
5721        let diff_transforms = self.diff_transforms.cursor(());
5722        MultiBufferCursor {
5723            excerpts,
5724            diff_transforms,
5725            diffs: &self.diffs,
5726            cached_region: OnceCell::new(),
5727        }
5728    }
5729
5730    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5731        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5732        let mut excerpts = self
5733            .excerpts
5734            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5735        excerpts.seek(&Some(start_locator), Bias::Left);
5736        excerpts.prev();
5737
5738        let mut diff_transforms = self
5739            .diff_transforms
5740            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5741        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5742        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5743            diff_transforms.next();
5744        }
5745
5746        let excerpt = excerpts.item()?;
5747        Some(MultiBufferExcerpt {
5748            excerpt,
5749            offset: diff_transforms.start().output_dimension.0,
5750            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5751            excerpt_offset: excerpts.start().1,
5752            diff_transforms,
5753        })
5754    }
5755
5756    pub fn excerpt_boundaries_in_range<R, T>(
5757        &self,
5758        range: R,
5759    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5760    where
5761        R: RangeBounds<T>,
5762        T: ToOffset,
5763    {
5764        let start_offset;
5765        let start = match range.start_bound() {
5766            Bound::Included(start) => {
5767                start_offset = start.to_offset(self);
5768                Bound::Included(start_offset)
5769            }
5770            Bound::Excluded(_) => {
5771                panic!("not supported")
5772            }
5773            Bound::Unbounded => {
5774                start_offset = MultiBufferOffset::ZERO;
5775                Bound::Unbounded
5776            }
5777        };
5778        let end = match range.end_bound() {
5779            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5780            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5781            Bound::Unbounded => Bound::Unbounded,
5782        };
5783        let bounds = (start, end);
5784        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5785        cursor.seek(&DimensionPair {
5786            key: start_offset,
5787            value: None,
5788        });
5789
5790        if cursor
5791            .region()
5792            .is_some_and(|region| bounds.contains(&region.range.start.key))
5793        {
5794            cursor.prev_excerpt();
5795        } else {
5796            cursor.seek_to_start_of_current_excerpt();
5797        }
5798        let mut prev_region = cursor.region().cloned();
5799
5800        cursor.next_excerpt();
5801
5802        iter::from_fn(move || {
5803            loop {
5804                if self.singleton {
5805                    return None;
5806                }
5807
5808                let next_region = cursor.region()?.clone();
5809                cursor.next_excerpt();
5810                if !bounds.contains(&next_region.range.start.key) {
5811                    prev_region = Some(next_region);
5812                    continue;
5813                }
5814
5815                let next_region_start = next_region.range.start.value.unwrap();
5816                let next_region_end = if let Some(region) = cursor.region() {
5817                    region.range.start.value.unwrap()
5818                } else {
5819                    self.max_point()
5820                };
5821
5822                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5823                    id: region.excerpt.id,
5824                    buffer: region.excerpt.buffer.clone(),
5825                    buffer_id: region.excerpt.buffer_id,
5826                    range: region.excerpt.range.clone(),
5827                    end_row: MultiBufferRow(next_region_start.row),
5828                });
5829
5830                let next = ExcerptInfo {
5831                    id: next_region.excerpt.id,
5832                    buffer: next_region.excerpt.buffer.clone(),
5833                    buffer_id: next_region.excerpt.buffer_id,
5834                    range: next_region.excerpt.range.clone(),
5835                    end_row: if next_region.excerpt.has_trailing_newline {
5836                        MultiBufferRow(next_region_end.row - 1)
5837                    } else {
5838                        MultiBufferRow(next_region_end.row)
5839                    },
5840                };
5841
5842                let row = MultiBufferRow(next_region_start.row);
5843
5844                prev_region = Some(next_region);
5845
5846                return Some(ExcerptBoundary { row, prev, next });
5847            }
5848        })
5849    }
5850
5851    pub fn edit_count(&self) -> usize {
5852        self.edit_count
5853    }
5854
5855    pub fn non_text_state_update_count(&self) -> usize {
5856        self.non_text_state_update_count
5857    }
5858
5859    /// Returns the smallest enclosing bracket ranges containing the given range or
5860    /// None if no brackets contain range or the range is not contained in a single
5861    /// excerpt
5862    ///
5863    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5864    #[ztracing::instrument(skip_all)]
5865    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5866        &self,
5867        range: Range<T>,
5868        range_filter: Option<
5869            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5870        >,
5871    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5872        let range = range.start.to_offset(self)..range.end.to_offset(self);
5873        let mut excerpt = self.excerpt_containing(range.clone())?;
5874        let buffer = excerpt.buffer();
5875        let excerpt_buffer_range = excerpt.buffer_range();
5876
5877        // Filter to ranges contained in the excerpt
5878        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5879            excerpt_buffer_range.contains(&BufferOffset(open.start))
5880                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5881                && range_filter.is_none_or(|filter| {
5882                    filter(
5883                        buffer,
5884                        BufferOffset(open.start)..BufferOffset(close.end),
5885                        BufferOffset(close.start)..BufferOffset(close.end),
5886                    )
5887                })
5888        };
5889
5890        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5891            excerpt.map_range_to_buffer(range),
5892            Some(&range_filter),
5893        )?;
5894
5895        Some((
5896            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5897            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5898        ))
5899    }
5900
5901    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5902    /// not contained in a single excerpt
5903    pub fn enclosing_bracket_ranges<T: ToOffset>(
5904        &self,
5905        range: Range<T>,
5906    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5907    {
5908        let range = range.start.to_offset(self)..range.end.to_offset(self);
5909        let mut excerpt = self.excerpt_containing(range.clone())?;
5910
5911        Some(
5912            excerpt
5913                .buffer()
5914                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5915                .filter_map(move |pair| {
5916                    let open_range =
5917                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5918                    let close_range =
5919                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5920                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5921                        Some((
5922                            excerpt.map_range_from_buffer(open_range),
5923                            excerpt.map_range_from_buffer(close_range),
5924                        ))
5925                    } else {
5926                        None
5927                    }
5928                }),
5929        )
5930    }
5931
5932    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5933    /// not contained in a single excerpt
5934    pub fn text_object_ranges<T: ToOffset>(
5935        &self,
5936        range: Range<T>,
5937        options: TreeSitterOptions,
5938    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5939        let range = range.start.to_offset(self)..range.end.to_offset(self);
5940        self.excerpt_containing(range.clone())
5941            .map(|mut excerpt| {
5942                excerpt
5943                    .buffer()
5944                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5945                    .filter_map(move |(range, text_object)| {
5946                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5947                        if excerpt.contains_buffer_range(range.clone()) {
5948                            Some((excerpt.map_range_from_buffer(range), text_object))
5949                        } else {
5950                            None
5951                        }
5952                    })
5953            })
5954            .into_iter()
5955            .flatten()
5956    }
5957
5958    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5959    /// not contained in a single excerpt
5960    pub fn bracket_ranges<T: ToOffset>(
5961        &self,
5962        range: Range<T>,
5963    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5964    {
5965        let range = range.start.to_offset(self)..range.end.to_offset(self);
5966        let mut excerpt = self.excerpt_containing(range.clone())?;
5967        Some(
5968            excerpt
5969                .buffer()
5970                .bracket_ranges(excerpt.map_range_to_buffer(range))
5971                .filter_map(move |pair| {
5972                    let open_range =
5973                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5974                    let close_range =
5975                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5976                    excerpt
5977                        .contains_buffer_range(open_range.start..close_range.end)
5978                        .then(|| BracketMatch {
5979                            open_range: excerpt.map_range_from_buffer(open_range),
5980                            close_range: excerpt.map_range_from_buffer(close_range),
5981                            color_index: pair.color_index,
5982                            newline_only: pair.newline_only,
5983                            syntax_layer_depth: pair.syntax_layer_depth,
5984                        })
5985                })
5986                .map(BracketMatch::bracket_ranges),
5987        )
5988    }
5989
5990    pub fn redacted_ranges<'a, T: ToOffset>(
5991        &'a self,
5992        range: Range<T>,
5993        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5994    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5995        let range = range.start.to_offset(self)..range.end.to_offset(self);
5996        self.lift_buffer_metadata(range, move |buffer, range| {
5997            if redaction_enabled(buffer.file()) {
5998                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5999            } else {
6000                None
6001            }
6002        })
6003        .map(|(range, _, _)| range)
6004    }
6005
6006    pub fn runnable_ranges(
6007        &self,
6008        range: Range<Anchor>,
6009    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6010        let range = range.start.to_offset(self)..range.end.to_offset(self);
6011        self.lift_buffer_metadata(range, move |buffer, range| {
6012            Some(
6013                buffer
6014                    .runnable_ranges(range.clone())
6015                    .filter(move |runnable| {
6016                        runnable.run_range.start >= range.start
6017                            && runnable.run_range.end < range.end
6018                    })
6019                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6020            )
6021        })
6022        .map(|(run_range, runnable, _)| (run_range, runnable))
6023    }
6024
6025    pub fn line_indents(
6026        &self,
6027        start_row: MultiBufferRow,
6028        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6029    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6030        let max_point = self.max_point();
6031        let mut cursor = self.cursor::<Point, Point>();
6032        cursor.seek(&Point::new(start_row.0, 0));
6033        iter::from_fn(move || {
6034            let mut region = cursor.region()?;
6035            while !buffer_filter(&region.excerpt.buffer) {
6036                cursor.next();
6037                region = cursor.region()?;
6038            }
6039            let region = cursor.region()?;
6040            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6041            let buffer_start_row =
6042                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6043
6044            let buffer_end_row = if region.is_main_buffer
6045                && (region.has_trailing_newline || region.range.end == max_point)
6046            {
6047                region.buffer_range.end.row
6048            } else {
6049                region.buffer_range.end.row.saturating_sub(1)
6050            };
6051
6052            let line_indents = region
6053                .buffer
6054                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6055            let region_buffer_row = region.buffer_range.start.row;
6056            let region_row = region.range.start.row;
6057            let region_buffer = &region.excerpt.buffer;
6058            cursor.next();
6059            Some(line_indents.map(move |(buffer_row, indent)| {
6060                let row = region_row + (buffer_row - region_buffer_row);
6061                (MultiBufferRow(row), indent, region_buffer)
6062            }))
6063        })
6064        .flatten()
6065    }
6066
6067    pub fn reversed_line_indents(
6068        &self,
6069        end_row: MultiBufferRow,
6070        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6071    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6072        let max_point = self.max_point();
6073        let mut cursor = self.cursor::<Point, Point>();
6074        cursor.seek(&Point::new(end_row.0, 0));
6075        iter::from_fn(move || {
6076            let mut region = cursor.region()?;
6077            while !buffer_filter(&region.excerpt.buffer) {
6078                cursor.prev();
6079                region = cursor.region()?;
6080            }
6081            let region = cursor.region()?;
6082
6083            let buffer_start_row = region.buffer_range.start.row;
6084            let buffer_end_row = if region.is_main_buffer
6085                && (region.has_trailing_newline || region.range.end == max_point)
6086            {
6087                region.buffer_range.end.row + 1
6088            } else {
6089                region.buffer_range.end.row
6090            };
6091
6092            let overshoot = end_row.0 - region.range.start.row;
6093            let buffer_end_row =
6094                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6095
6096            let line_indents = region
6097                .buffer
6098                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6099            let region_buffer_row = region.buffer_range.start.row;
6100            let region_row = region.range.start.row;
6101            let region_buffer = &region.excerpt.buffer;
6102            cursor.prev();
6103            Some(line_indents.map(move |(buffer_row, indent)| {
6104                let row = region_row + (buffer_row - region_buffer_row);
6105                (MultiBufferRow(row), indent, region_buffer)
6106            }))
6107        })
6108        .flatten()
6109    }
6110
6111    pub async fn enclosing_indent(
6112        &self,
6113        mut target_row: MultiBufferRow,
6114    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6115        let max_row = MultiBufferRow(self.max_point().row);
6116        if target_row >= max_row {
6117            return None;
6118        }
6119
6120        let mut target_indent = self.line_indent_for_row(target_row);
6121
6122        // If the current row is at the start of an indented block, we want to return this
6123        // block as the enclosing indent.
6124        if !target_indent.is_line_empty() && target_row < max_row {
6125            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6126            if !next_line_indent.is_line_empty()
6127                && target_indent.raw_len() < next_line_indent.raw_len()
6128            {
6129                target_indent = next_line_indent;
6130                target_row.0 += 1;
6131            }
6132        }
6133
6134        const SEARCH_ROW_LIMIT: u32 = 25000;
6135        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6136        const YIELD_INTERVAL: u32 = 100;
6137
6138        let mut accessed_row_counter = 0;
6139
6140        // If there is a blank line at the current row, search for the next non indented lines
6141        if target_indent.is_line_empty() {
6142            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6143            let end =
6144                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6145
6146            let mut non_empty_line_above = None;
6147            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6148                if row < start {
6149                    break;
6150                }
6151                accessed_row_counter += 1;
6152                if accessed_row_counter == YIELD_INTERVAL {
6153                    accessed_row_counter = 0;
6154                    yield_now().await;
6155                }
6156                if !indent.is_line_empty() {
6157                    non_empty_line_above = Some((row, indent));
6158                    break;
6159                }
6160            }
6161
6162            let mut non_empty_line_below = None;
6163            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6164                if row > end {
6165                    break;
6166                }
6167                accessed_row_counter += 1;
6168                if accessed_row_counter == YIELD_INTERVAL {
6169                    accessed_row_counter = 0;
6170                    yield_now().await;
6171                }
6172                if !indent.is_line_empty() {
6173                    non_empty_line_below = Some((row, indent));
6174                    break;
6175                }
6176            }
6177
6178            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6179                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6180                    if above_indent.raw_len() >= below_indent.raw_len() {
6181                        (above_row, above_indent)
6182                    } else {
6183                        (below_row, below_indent)
6184                    }
6185                }
6186                (Some(above), None) => above,
6187                (None, Some(below)) => below,
6188                _ => return None,
6189            };
6190
6191            target_indent = indent;
6192            target_row = row;
6193        }
6194
6195        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6196        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6197
6198        let mut start_indent = None;
6199        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6200            if row < start {
6201                break;
6202            }
6203            accessed_row_counter += 1;
6204            if accessed_row_counter == YIELD_INTERVAL {
6205                accessed_row_counter = 0;
6206                yield_now().await;
6207            }
6208            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6209                start_indent = Some((row, indent));
6210                break;
6211            }
6212        }
6213        let (start_row, start_indent_size) = start_indent?;
6214
6215        let mut end_indent = (end, None);
6216        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6217            if row > end {
6218                break;
6219            }
6220            accessed_row_counter += 1;
6221            if accessed_row_counter == YIELD_INTERVAL {
6222                accessed_row_counter = 0;
6223                yield_now().await;
6224            }
6225            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6226                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6227                break;
6228            }
6229        }
6230        let (end_row, end_indent_size) = end_indent;
6231
6232        let indent = if let Some(end_indent_size) = end_indent_size {
6233            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6234                start_indent_size
6235            } else {
6236                end_indent_size
6237            }
6238        } else {
6239            start_indent_size
6240        };
6241
6242        Some((start_row..end_row, indent))
6243    }
6244
6245    pub fn indent_guides_in_range<T: ToPoint>(
6246        &self,
6247        range: Range<T>,
6248        ignore_disabled_for_language: bool,
6249        cx: &App,
6250    ) -> impl Iterator<Item = IndentGuide> {
6251        let range = range.start.to_point(self)..range.end.to_point(self);
6252        let start_row = MultiBufferRow(range.start.row);
6253        let end_row = MultiBufferRow(range.end.row);
6254
6255        let mut row_indents = self.line_indents(start_row, |buffer| {
6256            let settings =
6257                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6258            settings.indent_guides.enabled || ignore_disabled_for_language
6259        });
6260
6261        let mut result = Vec::new();
6262        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6263
6264        let mut prev_settings = None;
6265        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6266            if first_row > end_row {
6267                break;
6268            }
6269            let current_depth = indent_stack.len() as u32;
6270
6271            // Avoid retrieving the language settings repeatedly for every buffer row.
6272            if let Some((prev_buffer_id, _)) = &prev_settings
6273                && prev_buffer_id != &buffer.remote_id()
6274            {
6275                prev_settings.take();
6276            }
6277            let settings = &prev_settings
6278                .get_or_insert_with(|| {
6279                    (
6280                        buffer.remote_id(),
6281                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6282                    )
6283                })
6284                .1;
6285            let tab_size = settings.tab_size.get();
6286
6287            // When encountering empty, continue until found useful line indent
6288            // then add to the indent stack with the depth found
6289            let mut found_indent = false;
6290            let mut last_row = first_row;
6291            if line_indent.is_line_blank() {
6292                while !found_indent {
6293                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6294                        break;
6295                    };
6296                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6297                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6298                        break;
6299                    }
6300
6301                    if new_line_indent.is_line_blank() {
6302                        continue;
6303                    }
6304                    last_row = target_row.min(end_row);
6305                    line_indent = new_line_indent;
6306                    found_indent = true;
6307                    break;
6308                }
6309            } else {
6310                found_indent = true
6311            }
6312
6313            let depth = if found_indent {
6314                line_indent.len(tab_size) / tab_size
6315            } else {
6316                0
6317            };
6318
6319            match depth.cmp(&current_depth) {
6320                cmp::Ordering::Less => {
6321                    for _ in 0..(current_depth - depth) {
6322                        let mut indent = indent_stack.pop().unwrap();
6323                        if last_row != first_row {
6324                            // In this case, we landed on an empty row, had to seek forward,
6325                            // and discovered that the indent we where on is ending.
6326                            // This means that the last display row must
6327                            // be on line that ends this indent range, so we
6328                            // should display the range up to the first non-empty line
6329                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6330                        }
6331
6332                        result.push(indent)
6333                    }
6334                }
6335                cmp::Ordering::Greater => {
6336                    for next_depth in current_depth..depth {
6337                        indent_stack.push(IndentGuide {
6338                            buffer_id: buffer.remote_id(),
6339                            start_row: first_row,
6340                            end_row: last_row,
6341                            depth: next_depth,
6342                            tab_size,
6343                            settings: settings.indent_guides.clone(),
6344                        });
6345                    }
6346                }
6347                _ => {}
6348            }
6349
6350            for indent in indent_stack.iter_mut() {
6351                indent.end_row = last_row;
6352            }
6353        }
6354
6355        result.extend(indent_stack);
6356        result.into_iter()
6357    }
6358
6359    pub fn trailing_excerpt_update_count(&self) -> usize {
6360        self.trailing_excerpt_update_count
6361    }
6362
6363    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6364        self.point_to_buffer_offset(point)
6365            .and_then(|(buffer, _)| buffer.file())
6366    }
6367
6368    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6369        self.point_to_buffer_offset(offset)
6370            .and_then(|(buffer, offset)| buffer.language_at(offset))
6371    }
6372
6373    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6374        self.excerpts
6375            .first()
6376            .map(|excerpt| &excerpt.buffer)
6377            .map(|buffer| {
6378                language_settings(
6379                    buffer.language().map(|language| language.name()),
6380                    buffer.file(),
6381                    cx,
6382                )
6383            })
6384            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6385    }
6386
6387    pub fn language_settings_at<'a, T: ToOffset>(
6388        &'a self,
6389        point: T,
6390        cx: &'a App,
6391    ) -> Cow<'a, LanguageSettings> {
6392        let mut language = None;
6393        let mut file = None;
6394        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6395            language = buffer.language_at(offset);
6396            file = buffer.file();
6397        }
6398        language_settings(language.map(|l| l.name()), file, cx)
6399    }
6400
6401    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6402        self.point_to_buffer_offset(point)
6403            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6404    }
6405
6406    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6407        self.point_to_buffer_offset(point)
6408            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6409            .unwrap_or_default()
6410    }
6411
6412    pub fn language_indent_size_at<T: ToOffset>(
6413        &self,
6414        position: T,
6415        cx: &App,
6416    ) -> Option<IndentSize> {
6417        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6418        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6419    }
6420
6421    pub fn is_dirty(&self) -> bool {
6422        self.is_dirty
6423    }
6424
6425    pub fn has_deleted_file(&self) -> bool {
6426        self.has_deleted_file
6427    }
6428
6429    pub fn has_conflict(&self) -> bool {
6430        self.has_conflict
6431    }
6432
6433    pub fn has_diagnostics(&self) -> bool {
6434        self.excerpts
6435            .iter()
6436            .any(|excerpt| excerpt.buffer.has_diagnostics())
6437    }
6438
6439    pub fn diagnostic_group(
6440        &self,
6441        buffer_id: BufferId,
6442        group_id: usize,
6443    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6444        self.lift_buffer_metadata::<Point, _, _>(
6445            Point::zero()..self.max_point(),
6446            move |buffer, range| {
6447                if buffer.remote_id() != buffer_id {
6448                    return None;
6449                };
6450                Some(
6451                    buffer
6452                        .diagnostics_in_range(range, false)
6453                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6454                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6455                )
6456            },
6457        )
6458        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6459    }
6460
6461    pub fn diagnostics_in_range<'a, MBD>(
6462        &'a self,
6463        range: Range<MBD>,
6464    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6465    where
6466        MBD::TextDimension: 'a
6467            + text::ToOffset
6468            + text::FromAnchor
6469            + Sub<Output = MBD::TextDimension>
6470            + fmt::Debug
6471            + ops::Add<Output = MBD::TextDimension>
6472            + ops::AddAssign
6473            + Ord,
6474        MBD: MultiBufferDimension
6475            + Ord
6476            + Sub<Output = MBD::TextDimension>
6477            + ops::Add<MBD::TextDimension, Output = MBD>
6478            + ops::AddAssign<MBD::TextDimension>
6479            + 'a,
6480    {
6481        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6482            Some(
6483                buffer
6484                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6485                    .map(|entry| (entry.range, entry.diagnostic)),
6486            )
6487        })
6488        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6489    }
6490
6491    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6492        &'a self,
6493        range: Range<MBD>,
6494    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6495    where
6496        MBD: MultiBufferDimension
6497            + Ord
6498            + Sub<Output = MBD::TextDimension>
6499            + ops::Add<MBD::TextDimension, Output = MBD>
6500            + ops::AddAssign<MBD::TextDimension>,
6501        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6502            + ops::Add<Output = MBD::TextDimension>
6503            + text::ToOffset
6504            + text::FromAnchor
6505            + AddAssign<MBD::TextDimension>
6506            + Ord,
6507    {
6508        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6509            Some(
6510                buffer
6511                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6512                    .map(|entry| (entry.range, entry.diagnostic)),
6513            )
6514        })
6515        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6516    }
6517
6518    pub fn syntax_ancestor<T: ToOffset>(
6519        &self,
6520        range: Range<T>,
6521    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6522        let range = range.start.to_offset(self)..range.end.to_offset(self);
6523        let mut excerpt = self.excerpt_containing(range.clone())?;
6524        let node = excerpt
6525            .buffer()
6526            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6527        let node_range = node.byte_range();
6528        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6529        if !excerpt.contains_buffer_range(node_range.clone()) {
6530            return None;
6531        };
6532        Some((node, excerpt.map_range_from_buffer(node_range)))
6533    }
6534
6535    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6536        let (excerpt_id, _, buffer) = self.as_singleton()?;
6537        let outline = buffer.outline(theme);
6538        Some(Outline::new(
6539            outline
6540                .items
6541                .into_iter()
6542                .flat_map(|item| {
6543                    Some(OutlineItem {
6544                        depth: item.depth,
6545                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6546                        source_range_for_text: self
6547                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6548                        text: item.text,
6549                        highlight_ranges: item.highlight_ranges,
6550                        name_ranges: item.name_ranges,
6551                        body_range: item.body_range.and_then(|body_range| {
6552                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6553                        }),
6554                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6555                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6556                        }),
6557                    })
6558                })
6559                .collect(),
6560        ))
6561    }
6562
6563    pub fn symbols_containing<T: ToOffset>(
6564        &self,
6565        offset: T,
6566        theme: Option<&SyntaxTheme>,
6567    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6568        let anchor = self.anchor_before(offset);
6569        let excerpt @ &Excerpt {
6570            id: excerpt_id,
6571            buffer_id,
6572            ref buffer,
6573            ..
6574        } = self.excerpt(anchor.excerpt_id)?;
6575        if cfg!(debug_assertions) {
6576            match anchor.text_anchor.buffer_id {
6577                // we clearly are hitting this according to sentry, but in what situations can this occur?
6578                Some(anchor_buffer_id) => {
6579                    assert_eq!(
6580                        anchor_buffer_id, buffer_id,
6581                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6582                    )
6583                }
6584                None => assert!(anchor.is_max()),
6585            }
6586        };
6587        Some((
6588            buffer_id,
6589            buffer
6590                .symbols_containing(anchor.text_anchor, theme)
6591                .into_iter()
6592                .flat_map(|item| {
6593                    Some(OutlineItem {
6594                        depth: item.depth,
6595                        source_range_for_text: Anchor::range_in_buffer(
6596                            excerpt_id,
6597                            item.source_range_for_text,
6598                        ),
6599                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6600                        text: item.text,
6601                        highlight_ranges: item.highlight_ranges,
6602                        name_ranges: item.name_ranges,
6603                        body_range: item
6604                            .body_range
6605                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6606                        annotation_range: item
6607                            .annotation_range
6608                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6609                    })
6610                })
6611                .collect(),
6612        ))
6613    }
6614
6615    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6616        if id == ExcerptId::min() {
6617            Locator::min_ref()
6618        } else if id == ExcerptId::max() {
6619            Locator::max_ref()
6620        } else {
6621            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6622            if let Some(entry) = item
6623                && entry.id == id
6624            {
6625                return &entry.locator;
6626            }
6627            panic!("invalid excerpt id {id:?}")
6628        }
6629    }
6630
6631    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6632    fn excerpt_locators_for_ids(
6633        &self,
6634        ids: impl IntoIterator<Item = ExcerptId>,
6635    ) -> SmallVec<[Locator; 1]> {
6636        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6637        sorted_ids.sort_unstable();
6638        sorted_ids.dedup();
6639        let mut locators = SmallVec::new();
6640
6641        while sorted_ids.last() == Some(&ExcerptId::max()) {
6642            sorted_ids.pop();
6643            locators.push(Locator::max());
6644        }
6645
6646        let mut sorted_ids = sorted_ids.into_iter().peekable();
6647        locators.extend(
6648            sorted_ids
6649                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6650                .map(|_| Locator::min()),
6651        );
6652
6653        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6654        for id in sorted_ids {
6655            if cursor.seek_forward(&id, Bias::Left) {
6656                locators.push(cursor.item().unwrap().locator.clone());
6657            } else {
6658                panic!("invalid excerpt id {:?}", id);
6659            }
6660        }
6661
6662        locators.sort_unstable();
6663        locators
6664    }
6665
6666    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6667        Some(self.excerpt(excerpt_id)?.buffer_id)
6668    }
6669
6670    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6671        Some(&self.excerpt(excerpt_id)?.buffer)
6672    }
6673
6674    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6675        let mut cursor = self
6676            .excerpts
6677            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6678        let locator = self.excerpt_locator_for_id(excerpt_id);
6679        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6680        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6681            sought_exact = true;
6682            cursor.prev();
6683        } else if excerpt_id == ExcerptId::min() {
6684            sought_exact = true;
6685        }
6686        if sought_exact {
6687            let start = cursor.start().1;
6688            let end = cursor.end().1;
6689            let mut diff_transforms = self
6690                .diff_transforms
6691                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6692            diff_transforms.seek(&start, Bias::Left);
6693            let overshoot = start - diff_transforms.start().0;
6694            let start = diff_transforms.start().1 + overshoot;
6695            diff_transforms.seek(&end, Bias::Right);
6696            let overshoot = end - diff_transforms.start().0;
6697            let end = diff_transforms.start().1 + overshoot;
6698            Some(start.0..end.0)
6699        } else {
6700            None
6701        }
6702    }
6703
6704    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6705    /// to have the latest excerpt id for the one passed in and will also remap
6706    /// `ExcerptId::max()` to the corresponding excertp ID.
6707    ///
6708    /// Callers of this function should generally use the resulting excerpt's `id` field
6709    /// afterwards.
6710    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6711        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6712        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6713        let locator = self.excerpt_locator_for_id(excerpt_id);
6714        cursor.seek(&Some(locator), Bias::Left);
6715        if let Some(excerpt) = cursor.item()
6716            && excerpt.id == excerpt_id
6717        {
6718            return Some(excerpt);
6719        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6720            cursor.prev();
6721            return cursor.item();
6722        }
6723        None
6724    }
6725
6726    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6727    pub fn excerpt_containing<T: ToOffset>(
6728        &self,
6729        range: Range<T>,
6730    ) -> Option<MultiBufferExcerpt<'_>> {
6731        let range = range.start.to_offset(self)..range.end.to_offset(self);
6732        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6733        cursor.seek(&range.start);
6734
6735        let start_excerpt = cursor.excerpt()?;
6736        if range.end != range.start {
6737            cursor.seek_forward(&range.end);
6738            if cursor.excerpt()?.id != start_excerpt.id {
6739                return None;
6740            }
6741        }
6742
6743        cursor.seek_to_start_of_current_excerpt();
6744        let region = cursor.region()?;
6745        let offset = region.range.start;
6746        let buffer_offset = start_excerpt.buffer_start_offset();
6747        let excerpt_offset = *cursor.excerpts.start();
6748        Some(MultiBufferExcerpt {
6749            diff_transforms: cursor.diff_transforms,
6750            excerpt: start_excerpt,
6751            offset,
6752            buffer_offset,
6753            excerpt_offset,
6754        })
6755    }
6756
6757    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6758        if let Some(id) = anchor.text_anchor.buffer_id {
6759            return Some(id);
6760        }
6761        let excerpt = self.excerpt_containing(anchor..anchor)?;
6762        Some(excerpt.buffer_id())
6763    }
6764
6765    pub fn selections_in_range<'a>(
6766        &'a self,
6767        range: &'a Range<Anchor>,
6768        include_local: bool,
6769    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6770        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6771        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6772        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6773        cursor.seek(start_locator, Bias::Left);
6774        cursor
6775            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6776            .flat_map(move |excerpt| {
6777                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6778                if excerpt.id == range.start.excerpt_id {
6779                    query_range.start = range.start.text_anchor;
6780                }
6781                if excerpt.id == range.end.excerpt_id {
6782                    query_range.end = range.end.text_anchor;
6783                }
6784
6785                excerpt
6786                    .buffer
6787                    .selections_in_range(query_range, include_local)
6788                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6789                        selections.map(move |selection| {
6790                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6791                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6792                            if range.start.cmp(&start, self).is_gt() {
6793                                start = range.start;
6794                            }
6795                            if range.end.cmp(&end, self).is_lt() {
6796                                end = range.end;
6797                            }
6798
6799                            (
6800                                replica_id,
6801                                line_mode,
6802                                cursor_shape,
6803                                Selection {
6804                                    id: selection.id,
6805                                    start,
6806                                    end,
6807                                    reversed: selection.reversed,
6808                                    goal: selection.goal,
6809                                },
6810                            )
6811                        })
6812                    })
6813            })
6814    }
6815
6816    pub fn show_headers(&self) -> bool {
6817        self.show_headers
6818    }
6819
6820    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6821        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6822    }
6823
6824    pub fn all_diff_hunks_expanded(&self) -> bool {
6825        self.all_diff_hunks_expanded
6826    }
6827
6828    /// Visually annotates a position or range with the `Debug` representation of a value. The
6829    /// callsite of this function is used as a key - previous annotations will be removed.
6830    #[cfg(debug_assertions)]
6831    #[track_caller]
6832    pub fn debug<V, R>(&self, ranges: &R, value: V)
6833    where
6834        R: debug::ToMultiBufferDebugRanges,
6835        V: std::fmt::Debug,
6836    {
6837        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6838    }
6839
6840    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6841    /// debug annotations with the same key will be removed. The key is also used to determine the
6842    /// annotation's color.
6843    #[cfg(debug_assertions)]
6844    #[track_caller]
6845    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6846    where
6847        K: std::hash::Hash + 'static,
6848        R: debug::ToMultiBufferDebugRanges,
6849        V: std::fmt::Debug,
6850    {
6851        let text_ranges = ranges
6852            .to_multi_buffer_debug_ranges(self)
6853            .into_iter()
6854            .flat_map(|range| {
6855                self.range_to_buffer_ranges(range.start..=range.end)
6856                    .into_iter()
6857                    .map(|(buffer, range, _excerpt_id)| {
6858                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6859                    })
6860            })
6861            .collect();
6862        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6863            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6864        });
6865    }
6866
6867    fn excerpt_edits_for_diff_change(
6868        &self,
6869        buffer_state: &BufferState,
6870        diff_change_range: Range<usize>,
6871    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6872        let mut excerpt_edits = Vec::new();
6873        for locator in &buffer_state.excerpts {
6874            let mut cursor = self
6875                .excerpts
6876                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6877            cursor.seek_forward(&Some(locator), Bias::Left);
6878            if let Some(excerpt) = cursor.item()
6879                && excerpt.locator == *locator
6880            {
6881                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6882                if diff_change_range.end < excerpt_buffer_range.start
6883                    || diff_change_range.start > excerpt_buffer_range.end
6884                {
6885                    continue;
6886                }
6887                let excerpt_start = cursor.start().1;
6888                let excerpt_len = excerpt.text_summary.len;
6889                let diff_change_start_in_excerpt = diff_change_range
6890                    .start
6891                    .saturating_sub(excerpt_buffer_range.start);
6892                let diff_change_end_in_excerpt = diff_change_range
6893                    .end
6894                    .saturating_sub(excerpt_buffer_range.start);
6895                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6896                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6897                excerpt_edits.push(Edit {
6898                    old: edit_start..edit_end,
6899                    new: edit_start..edit_end,
6900                });
6901            }
6902        }
6903        excerpt_edits
6904    }
6905}
6906
6907#[cfg(any(test, feature = "test-support"))]
6908impl MultiBufferSnapshot {
6909    pub fn random_byte_range(
6910        &self,
6911        start_offset: MultiBufferOffset,
6912        rng: &mut impl rand::Rng,
6913    ) -> Range<MultiBufferOffset> {
6914        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6915        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6916        start..end
6917    }
6918
6919    #[cfg(any(test, feature = "test-support"))]
6920    fn check_invariants(&self) {
6921        let excerpts = self.excerpts.items(());
6922        let excerpt_ids = self.excerpt_ids.items(());
6923
6924        for (ix, excerpt) in excerpts.iter().enumerate() {
6925            if ix == 0 {
6926                if excerpt.locator <= Locator::min() {
6927                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6928                }
6929            } else if excerpt.locator <= excerpts[ix - 1].locator {
6930                panic!("excerpts are out-of-order: {:?}", excerpts);
6931            }
6932        }
6933
6934        for (ix, entry) in excerpt_ids.iter().enumerate() {
6935            if ix == 0 {
6936                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6937                    panic!("invalid first excerpt id {:?}", entry.id);
6938                }
6939            } else if entry.id <= excerpt_ids[ix - 1].id {
6940                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6941            }
6942        }
6943
6944        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6945            panic!(
6946                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6947                self.excerpts.summary().text,
6948                self.diff_transforms.summary().input,
6949                self.diff_transforms.items(()),
6950            );
6951        }
6952
6953        let mut prev_transform: Option<&DiffTransform> = None;
6954        for item in self.diff_transforms.iter() {
6955            if let DiffTransform::BufferContent {
6956                summary,
6957                inserted_hunk_info,
6958            } = item
6959            {
6960                if let Some(DiffTransform::BufferContent {
6961                    inserted_hunk_info: prev_inserted_hunk_info,
6962                    ..
6963                }) = prev_transform
6964                    && *inserted_hunk_info == *prev_inserted_hunk_info
6965                {
6966                    panic!(
6967                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6968                        self.diff_transforms.items(())
6969                    );
6970                }
6971                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6972                    panic!("empty buffer content transform");
6973                }
6974            }
6975            prev_transform = Some(item);
6976        }
6977    }
6978}
6979
6980impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6981where
6982    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6983    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6984{
6985    #[instrument(skip_all)]
6986    fn seek(&mut self, position: &MBD) {
6987        let position = OutputDimension(*position);
6988        self.cached_region.take();
6989        self.diff_transforms.seek(&position, Bias::Right);
6990        if self.diff_transforms.item().is_none()
6991            && self.diff_transforms.start().output_dimension == position
6992        {
6993            self.diff_transforms.prev();
6994        }
6995
6996        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6997        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6998            let overshoot = position - self.diff_transforms.start().output_dimension;
6999            excerpt_position += overshoot;
7000        }
7001
7002        self.excerpts.seek(&excerpt_position, Bias::Right);
7003        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7004            self.excerpts.prev();
7005        }
7006    }
7007
7008    fn seek_forward(&mut self, position: &MBD) {
7009        let position = OutputDimension(*position);
7010        self.cached_region.take();
7011        self.diff_transforms.seek_forward(&position, Bias::Right);
7012        if self.diff_transforms.item().is_none()
7013            && self.diff_transforms.start().output_dimension == position
7014        {
7015            self.diff_transforms.prev();
7016        }
7017
7018        let overshoot = position - self.diff_transforms.start().output_dimension;
7019        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7020        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7021            excerpt_position += overshoot;
7022        }
7023
7024        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7025        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7026            self.excerpts.prev();
7027        }
7028    }
7029
7030    fn next_excerpt(&mut self) {
7031        self.excerpts.next();
7032        self.seek_to_start_of_current_excerpt();
7033    }
7034
7035    fn prev_excerpt(&mut self) {
7036        self.excerpts.prev();
7037        self.seek_to_start_of_current_excerpt();
7038    }
7039
7040    fn seek_to_start_of_current_excerpt(&mut self) {
7041        self.cached_region.take();
7042        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
7043        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
7044            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7045            && self.diff_transforms.next_item().is_some()
7046        {
7047            self.diff_transforms.next();
7048        }
7049    }
7050
7051    fn next(&mut self) {
7052        self.cached_region.take();
7053        match self
7054            .diff_transforms
7055            .end()
7056            .excerpt_dimension
7057            .cmp(&self.excerpts.end())
7058        {
7059            cmp::Ordering::Less => self.diff_transforms.next(),
7060            cmp::Ordering::Greater => self.excerpts.next(),
7061            cmp::Ordering::Equal => {
7062                self.diff_transforms.next();
7063                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7064                    || self.diff_transforms.item().is_none()
7065                {
7066                    self.excerpts.next();
7067                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7068                    self.diff_transforms.item()
7069                    && self
7070                        .excerpts
7071                        .item()
7072                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7073                {
7074                    self.excerpts.next();
7075                }
7076            }
7077        }
7078    }
7079
7080    fn prev(&mut self) {
7081        self.cached_region.take();
7082        match self
7083            .diff_transforms
7084            .start()
7085            .excerpt_dimension
7086            .cmp(self.excerpts.start())
7087        {
7088            cmp::Ordering::Less => self.excerpts.prev(),
7089            cmp::Ordering::Greater => self.diff_transforms.prev(),
7090            cmp::Ordering::Equal => {
7091                self.diff_transforms.prev();
7092                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7093                    || self.diff_transforms.item().is_none()
7094                {
7095                    self.excerpts.prev();
7096                }
7097            }
7098        }
7099    }
7100
7101    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7102        self.cached_region
7103            .get_or_init(|| self.build_region())
7104            .as_ref()
7105    }
7106
7107    fn is_at_start_of_excerpt(&mut self) -> bool {
7108        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7109            return false;
7110        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7111            return true;
7112        }
7113
7114        self.diff_transforms.prev();
7115        let prev_transform = self.diff_transforms.item();
7116        self.diff_transforms.next();
7117
7118        prev_transform.is_none_or(|next_transform| {
7119            matches!(next_transform, DiffTransform::BufferContent { .. })
7120        })
7121    }
7122
7123    fn is_at_end_of_excerpt(&self) -> bool {
7124        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7125            return false;
7126        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7127            || self.diff_transforms.item().is_none()
7128        {
7129            return true;
7130        }
7131
7132        let next_transform = self.diff_transforms.next_item();
7133        next_transform.is_none_or(|next_transform| match next_transform {
7134            DiffTransform::BufferContent { .. } => true,
7135            DiffTransform::DeletedHunk { hunk_info, .. } => self
7136                .excerpts
7137                .item()
7138                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7139        })
7140    }
7141
7142    fn main_buffer_position(&self) -> Option<BD> {
7143        let excerpt = self.excerpts.item()?;
7144        let buffer = &excerpt.buffer;
7145        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7146        let mut buffer_start = buffer_context_start;
7147        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7148        buffer_start += overshoot;
7149        Some(buffer_start)
7150    }
7151
7152    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7153        let excerpt = self.excerpts.item()?;
7154        match self.diff_transforms.item()? {
7155            DiffTransform::DeletedHunk {
7156                buffer_id,
7157                base_text_byte_range,
7158                has_trailing_newline,
7159                hunk_info,
7160                ..
7161            } => {
7162                let diff = self.diffs.get(buffer_id)?;
7163                let buffer = diff.base_text();
7164                let mut rope_cursor = buffer.as_rope().cursor(0);
7165                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7166                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7167                let mut buffer_end = buffer_start;
7168                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7169                let start = self.diff_transforms.start().output_dimension.0;
7170                let end = self.diff_transforms.end().output_dimension.0;
7171                Some(MultiBufferRegion {
7172                    buffer,
7173                    excerpt,
7174                    has_trailing_newline: *has_trailing_newline,
7175                    is_main_buffer: false,
7176                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7177                        hunk_info.hunk_secondary_status,
7178                    )),
7179                    buffer_range: buffer_start..buffer_end,
7180                    range: start..end,
7181                })
7182            }
7183            DiffTransform::BufferContent {
7184                inserted_hunk_info, ..
7185            } => {
7186                let buffer = &excerpt.buffer;
7187                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7188
7189                let mut start = self.diff_transforms.start().output_dimension.0;
7190                let mut buffer_start = buffer_context_start;
7191                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7192                    let overshoot =
7193                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7194                    start += overshoot;
7195                } else {
7196                    let overshoot =
7197                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7198                    buffer_start += overshoot;
7199                }
7200
7201                let mut end;
7202                let mut buffer_end;
7203                let has_trailing_newline;
7204                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7205                    let overshoot =
7206                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7207                    end = self.diff_transforms.end().output_dimension.0;
7208                    buffer_end = buffer_context_start;
7209                    buffer_end += overshoot;
7210                    has_trailing_newline = false;
7211                } else {
7212                    let overshoot =
7213                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7214                    end = self.diff_transforms.start().output_dimension.0;
7215                    end += overshoot;
7216                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7217                    has_trailing_newline = excerpt.has_trailing_newline;
7218                };
7219
7220                let diff_hunk_status = inserted_hunk_info.map(|info| {
7221                    if info.is_logically_deleted {
7222                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7223                    } else {
7224                        DiffHunkStatus::added(info.hunk_secondary_status)
7225                    }
7226                });
7227
7228                Some(MultiBufferRegion {
7229                    buffer,
7230                    excerpt,
7231                    has_trailing_newline,
7232                    is_main_buffer: true,
7233                    diff_hunk_status,
7234                    buffer_range: buffer_start..buffer_end,
7235                    range: start..end,
7236                })
7237            }
7238        }
7239    }
7240
7241    fn excerpt(&self) -> Option<&'a Excerpt> {
7242        self.excerpts.item()
7243    }
7244}
7245
7246impl Excerpt {
7247    fn new(
7248        id: ExcerptId,
7249        locator: Locator,
7250        buffer_id: BufferId,
7251        buffer: BufferSnapshot,
7252        range: ExcerptRange<text::Anchor>,
7253        has_trailing_newline: bool,
7254    ) -> Self {
7255        Excerpt {
7256            id,
7257            locator,
7258            max_buffer_row: range.context.end.to_point(&buffer).row,
7259            text_summary: buffer
7260                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7261            buffer_id,
7262            buffer,
7263            range,
7264            has_trailing_newline,
7265        }
7266    }
7267
7268    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7269        let content_start = self.range.context.start.to_offset(&self.buffer);
7270        let chunks_start = content_start + range.start;
7271        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7272
7273        let has_footer = self.has_trailing_newline
7274            && range.start <= self.text_summary.len
7275            && range.end > self.text_summary.len;
7276
7277        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7278
7279        ExcerptChunks {
7280            excerpt_id: self.id,
7281            content_chunks,
7282            has_footer,
7283        }
7284    }
7285
7286    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7287        let content_start = self.range.context.start.to_offset(&self.buffer);
7288        let chunks_start = content_start + range.start;
7289        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7290        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7291        excerpt_chunks.has_footer = self.has_trailing_newline
7292            && range.start <= self.text_summary.len
7293            && range.end > self.text_summary.len;
7294    }
7295
7296    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7297        if text_anchor
7298            .cmp(&self.range.context.start, &self.buffer)
7299            .is_lt()
7300        {
7301            self.range.context.start
7302        } else if text_anchor
7303            .cmp(&self.range.context.end, &self.buffer)
7304            .is_gt()
7305        {
7306            self.range.context.end
7307        } else {
7308            text_anchor
7309        }
7310    }
7311
7312    fn contains(&self, anchor: &Anchor) -> bool {
7313        (anchor.text_anchor.buffer_id == None
7314            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7315            && self
7316                .range
7317                .context
7318                .start
7319                .cmp(&anchor.text_anchor, &self.buffer)
7320                .is_le()
7321            && self
7322                .range
7323                .context
7324                .end
7325                .cmp(&anchor.text_anchor, &self.buffer)
7326                .is_ge()
7327    }
7328
7329    fn contains_diffbaseless(&self, anchor: &DiffbaselessAnchor) -> bool {
7330        (anchor.text_anchor.buffer_id == None
7331            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7332            && self
7333                .range
7334                .context
7335                .start
7336                .cmp(&anchor.text_anchor, &self.buffer)
7337                .is_le()
7338            && self
7339                .range
7340                .context
7341                .end
7342                .cmp(&anchor.text_anchor, &self.buffer)
7343                .is_ge()
7344    }
7345
7346    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7347    fn buffer_start_offset(&self) -> BufferOffset {
7348        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7349    }
7350
7351    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7352    fn buffer_end_offset(&self) -> BufferOffset {
7353        self.buffer_start_offset() + self.text_summary.len
7354    }
7355}
7356
7357impl<'a> MultiBufferExcerpt<'a> {
7358    pub fn id(&self) -> ExcerptId {
7359        self.excerpt.id
7360    }
7361
7362    pub fn buffer_id(&self) -> BufferId {
7363        self.excerpt.buffer_id
7364    }
7365
7366    pub fn start_anchor(&self) -> Anchor {
7367        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7368    }
7369
7370    pub fn end_anchor(&self) -> Anchor {
7371        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7372    }
7373
7374    pub fn buffer(&self) -> &'a BufferSnapshot {
7375        &self.excerpt.buffer
7376    }
7377
7378    pub fn buffer_range(&self) -> Range<BufferOffset> {
7379        self.buffer_offset
7380            ..BufferOffset(
7381                self.excerpt
7382                    .range
7383                    .context
7384                    .end
7385                    .to_offset(&self.excerpt.buffer.text),
7386            )
7387    }
7388
7389    pub fn start_offset(&self) -> MultiBufferOffset {
7390        self.offset
7391    }
7392
7393    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7394    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7395        self.map_range_to_buffer(offset..offset).start
7396    }
7397
7398    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7399    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7400        self.diff_transforms
7401            .seek(&OutputDimension(range.start), Bias::Right);
7402        let start = self.map_offset_to_buffer_internal(range.start);
7403        let end = if range.end > range.start {
7404            self.diff_transforms
7405                .seek_forward(&OutputDimension(range.end), Bias::Right);
7406            self.map_offset_to_buffer_internal(range.end)
7407        } else {
7408            start
7409        };
7410        start..end
7411    }
7412
7413    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7414        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7415        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7416            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7417        };
7418        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7419        self.buffer_offset + offset_in_excerpt
7420    }
7421
7422    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7423    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7424        self.map_range_from_buffer(buffer_offset..buffer_offset)
7425            .start
7426    }
7427
7428    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7429    pub fn map_range_from_buffer(
7430        &mut self,
7431        buffer_range: Range<BufferOffset>,
7432    ) -> Range<MultiBufferOffset> {
7433        if buffer_range.start < self.buffer_offset {
7434            log::warn!(
7435                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7436            );
7437            return self.offset..self.offset;
7438        }
7439        let overshoot = buffer_range.start - self.buffer_offset;
7440        let excerpt_offset = self.excerpt_offset + overshoot;
7441        let excerpt_seek_dim = excerpt_offset;
7442        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7443        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7444            log::warn!(
7445                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7446            );
7447            return self.offset..self.offset;
7448        }
7449        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7450        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7451
7452        let end = if buffer_range.start < buffer_range.end {
7453            let overshoot = buffer_range.end - self.buffer_offset;
7454            let excerpt_offset = self.excerpt_offset + overshoot;
7455            let excerpt_seek_dim = excerpt_offset;
7456            self.diff_transforms
7457                .seek_forward(&excerpt_seek_dim, Bias::Right);
7458            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7459            // todo(lw): Clamp end to the excerpt boundaries
7460            self.diff_transforms.start().output_dimension.0 + overshoot
7461        } else {
7462            start
7463        };
7464
7465        start..end
7466    }
7467
7468    /// Returns true if the entirety of the given range is in the buffer's excerpt
7469    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7470        range.start >= self.excerpt.buffer_start_offset()
7471            && range.end <= self.excerpt.buffer_end_offset()
7472    }
7473
7474    /// Returns true if any part of the given range is in the buffer's excerpt
7475    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7476        range.start <= self.excerpt.buffer_end_offset()
7477            && range.end >= self.excerpt.buffer_start_offset()
7478    }
7479
7480    pub fn max_buffer_row(&self) -> u32 {
7481        self.excerpt.max_buffer_row
7482    }
7483}
7484
7485impl ExcerptId {
7486    pub fn min() -> Self {
7487        Self(0)
7488    }
7489
7490    pub fn max() -> Self {
7491        Self(u32::MAX)
7492    }
7493
7494    pub fn to_proto(self) -> u64 {
7495        self.0 as _
7496    }
7497
7498    pub fn from_proto(proto: u64) -> Self {
7499        Self(proto as _)
7500    }
7501
7502    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7503        let a = snapshot.excerpt_locator_for_id(*self);
7504        let b = snapshot.excerpt_locator_for_id(*other);
7505        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7506    }
7507}
7508
7509impl From<ExcerptId> for usize {
7510    fn from(val: ExcerptId) -> Self {
7511        val.0 as usize
7512    }
7513}
7514
7515impl fmt::Debug for Excerpt {
7516    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7517        f.debug_struct("Excerpt")
7518            .field("id", &self.id)
7519            .field("locator", &self.locator)
7520            .field("buffer_id", &self.buffer_id)
7521            .field("range", &self.range)
7522            .field("text_summary", &self.text_summary)
7523            .field("has_trailing_newline", &self.has_trailing_newline)
7524            .finish()
7525    }
7526}
7527
7528impl sum_tree::Item for Excerpt {
7529    type Summary = ExcerptSummary;
7530
7531    fn summary(&self, _cx: ()) -> Self::Summary {
7532        let mut text = self.text_summary;
7533        if self.has_trailing_newline {
7534            text += TextSummary::from("\n");
7535        }
7536        ExcerptSummary {
7537            excerpt_id: self.id,
7538            excerpt_locator: self.locator.clone(),
7539            widest_line_number: self.max_buffer_row,
7540            text: text.into(),
7541        }
7542    }
7543}
7544
7545impl sum_tree::Item for ExcerptIdMapping {
7546    type Summary = ExcerptId;
7547
7548    fn summary(&self, _cx: ()) -> Self::Summary {
7549        self.id
7550    }
7551}
7552
7553impl sum_tree::KeyedItem for ExcerptIdMapping {
7554    type Key = ExcerptId;
7555
7556    fn key(&self) -> Self::Key {
7557        self.id
7558    }
7559}
7560
7561impl DiffTransform {
7562    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7563        match self {
7564            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7565            DiffTransform::BufferContent {
7566                inserted_hunk_info, ..
7567            } => *inserted_hunk_info,
7568        }
7569    }
7570}
7571
7572impl sum_tree::Item for DiffTransform {
7573    type Summary = DiffTransformSummary;
7574
7575    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7576        match self {
7577            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7578                input: *summary,
7579                output: *summary,
7580            },
7581            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7582                input: MBTextSummary::default(),
7583                output: summary.into(),
7584            },
7585        }
7586    }
7587}
7588
7589impl DiffTransformSummary {
7590    fn excerpt_len(&self) -> ExcerptOffset {
7591        ExcerptDimension(self.input.len)
7592    }
7593}
7594
7595impl sum_tree::ContextLessSummary for DiffTransformSummary {
7596    fn zero() -> Self {
7597        DiffTransformSummary {
7598            input: MBTextSummary::default(),
7599            output: MBTextSummary::default(),
7600        }
7601    }
7602
7603    fn add_summary(&mut self, other: &Self) {
7604        self.input += other.input;
7605        self.output += other.output;
7606    }
7607}
7608
7609impl sum_tree::ContextLessSummary for ExcerptId {
7610    fn zero() -> Self {
7611        Self(0)
7612    }
7613
7614    fn add_summary(&mut self, summary: &Self) {
7615        *self = cmp::max(*self, *summary);
7616    }
7617}
7618
7619impl sum_tree::ContextLessSummary for ExcerptSummary {
7620    fn zero() -> Self {
7621        Self::default()
7622    }
7623
7624    fn add_summary(&mut self, summary: &Self) {
7625        debug_assert!(
7626            summary.excerpt_locator > self.excerpt_locator
7627                || self.excerpt_locator == Locator::min(),
7628            "Excerpt locators must be in ascending order: {:?} > {:?}",
7629            summary.excerpt_locator,
7630            self.excerpt_locator
7631        );
7632        self.excerpt_locator = summary.excerpt_locator.clone();
7633        self.text += summary.text;
7634        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7635    }
7636}
7637
7638impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7639    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7640        Ord::cmp(&Some(self), cursor_location)
7641    }
7642}
7643
7644impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7645    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7646        Ord::cmp(self, &cursor_location.excerpt_locator)
7647    }
7648}
7649
7650impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7651where
7652    MBD: MultiBufferDimension + Default,
7653{
7654    fn zero(_: ()) -> Self {
7655        ExcerptDimension(MBD::default())
7656    }
7657
7658    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7659        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7660    }
7661}
7662
7663impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7664    fn zero(_cx: ()) -> Self {
7665        Default::default()
7666    }
7667
7668    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7669        *self = Some(&summary.excerpt_locator);
7670    }
7671}
7672
7673impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7674    fn zero(_cx: ()) -> Self {
7675        Default::default()
7676    }
7677
7678    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7679        *self = Some(summary.excerpt_id);
7680    }
7681}
7682
7683#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7684struct OutputDimension<T>(T);
7685
7686impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7687    fn eq(&self, other: &T) -> bool {
7688        self.0 == *other
7689    }
7690}
7691
7692impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7693    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7694        self.0.partial_cmp(other)
7695    }
7696}
7697
7698impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7699where
7700    T: ops::Sub<U, Output = R>,
7701{
7702    type Output = R;
7703
7704    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7705        self.0 - other.0
7706    }
7707}
7708
7709impl<R, T, U> ops::Add<U> for OutputDimension<T>
7710where
7711    T: ops::Add<U, Output = R>,
7712{
7713    type Output = OutputDimension<R>;
7714
7715    fn add(self, other: U) -> Self::Output {
7716        OutputDimension(self.0 + other)
7717    }
7718}
7719
7720impl<T, U> AddAssign<U> for OutputDimension<T>
7721where
7722    T: AddAssign<U>,
7723{
7724    fn add_assign(&mut self, other: U) {
7725        self.0 += other;
7726    }
7727}
7728
7729impl<T, U> SubAssign<U> for OutputDimension<T>
7730where
7731    T: SubAssign<U>,
7732{
7733    fn sub_assign(&mut self, other: U) {
7734        self.0 -= other;
7735    }
7736}
7737
7738#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7739struct ExcerptDimension<T>(T);
7740
7741impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7742    fn eq(&self, other: &T) -> bool {
7743        self.0 == *other
7744    }
7745}
7746
7747impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7748    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7749        self.0.partial_cmp(other)
7750    }
7751}
7752
7753impl ExcerptOffset {
7754    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7755        self.0.saturating_sub(other.0)
7756    }
7757}
7758
7759impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7760where
7761    T: ops::Sub<U, Output = R>,
7762{
7763    type Output = R;
7764
7765    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7766        self.0 - other.0
7767    }
7768}
7769
7770impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7771where
7772    T: ops::Add<U, Output = R>,
7773{
7774    type Output = ExcerptDimension<R>;
7775
7776    fn add(self, other: U) -> Self::Output {
7777        ExcerptDimension(self.0 + other)
7778    }
7779}
7780
7781impl<T, U> AddAssign<U> for ExcerptDimension<T>
7782where
7783    T: AddAssign<U>,
7784{
7785    fn add_assign(&mut self, other: U) {
7786        self.0 += other;
7787    }
7788}
7789
7790impl<T, U> SubAssign<U> for ExcerptDimension<T>
7791where
7792    T: SubAssign<U>,
7793{
7794    fn sub_assign(&mut self, other: U) {
7795        self.0 -= other;
7796    }
7797}
7798
7799impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7800    fn zero(_: ()) -> Self {
7801        MultiBufferOffset::ZERO
7802    }
7803
7804    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7805        *self += summary.output.len;
7806    }
7807}
7808
7809impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7810    for ExcerptDimension<MBD>
7811where
7812    MBD: MultiBufferDimension + Ord,
7813{
7814    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7815        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7816    }
7817}
7818
7819impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7820    for ExcerptDimension<MBD>
7821where
7822    MBD: MultiBufferDimension + Ord,
7823{
7824    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7825        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7826    }
7827}
7828
7829impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7830    for ExcerptDimension<MBD>
7831{
7832    fn zero(_: ()) -> Self {
7833        ExcerptDimension(MBD::default())
7834    }
7835
7836    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7837        self.0.add_mb_text_summary(&summary.input)
7838    }
7839}
7840
7841impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7842    for OutputDimension<MBD>
7843where
7844    MBD: MultiBufferDimension + Ord,
7845{
7846    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7847        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7848    }
7849}
7850
7851impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7852    for OutputDimension<MBD>
7853{
7854    fn zero(_: ()) -> Self {
7855        OutputDimension(MBD::default())
7856    }
7857
7858    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7859        self.0.add_mb_text_summary(&summary.output)
7860    }
7861}
7862
7863impl MultiBufferRows<'_> {
7864    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7865        self.point = Point::new(row, 0);
7866        self.cursor.seek(&self.point);
7867    }
7868}
7869
7870impl Iterator for MultiBufferRows<'_> {
7871    type Item = RowInfo;
7872
7873    fn next(&mut self) -> Option<Self::Item> {
7874        if self.is_empty && self.point.row == 0 {
7875            self.point += Point::new(1, 0);
7876            return Some(RowInfo {
7877                buffer_id: None,
7878                buffer_row: Some(0),
7879                multibuffer_row: Some(MultiBufferRow(0)),
7880                diff_status: None,
7881                expand_info: None,
7882                wrapped_buffer_row: None,
7883            });
7884        }
7885
7886        let mut region = self.cursor.region()?.clone();
7887        while self.point >= region.range.end {
7888            self.cursor.next();
7889            if let Some(next_region) = self.cursor.region() {
7890                region = next_region.clone();
7891            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7892                let multibuffer_row = MultiBufferRow(self.point.row);
7893                let last_excerpt = self
7894                    .cursor
7895                    .excerpts
7896                    .item()
7897                    .or(self.cursor.excerpts.prev_item())?;
7898                let last_row = last_excerpt
7899                    .range
7900                    .context
7901                    .end
7902                    .to_point(&last_excerpt.buffer)
7903                    .row;
7904
7905                let first_row = last_excerpt
7906                    .range
7907                    .context
7908                    .start
7909                    .to_point(&last_excerpt.buffer)
7910                    .row;
7911
7912                let expand_info = if self.is_singleton {
7913                    None
7914                } else {
7915                    let needs_expand_up = first_row == last_row
7916                        && last_row > 0
7917                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7918                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7919
7920                    if needs_expand_up && needs_expand_down {
7921                        Some(ExpandExcerptDirection::UpAndDown)
7922                    } else if needs_expand_up {
7923                        Some(ExpandExcerptDirection::Up)
7924                    } else if needs_expand_down {
7925                        Some(ExpandExcerptDirection::Down)
7926                    } else {
7927                        None
7928                    }
7929                    .map(|direction| ExpandInfo {
7930                        direction,
7931                        excerpt_id: last_excerpt.id,
7932                    })
7933                };
7934                self.point += Point::new(1, 0);
7935                return Some(RowInfo {
7936                    buffer_id: Some(last_excerpt.buffer_id),
7937                    buffer_row: Some(last_row),
7938                    multibuffer_row: Some(multibuffer_row),
7939                    diff_status: None,
7940                    wrapped_buffer_row: None,
7941                    expand_info,
7942                });
7943            } else {
7944                return None;
7945            };
7946        }
7947
7948        let overshoot = self.point - region.range.start;
7949        let buffer_point = region.buffer_range.start + overshoot;
7950        let expand_info = if self.is_singleton {
7951            None
7952        } else {
7953            let needs_expand_up = self.point.row == region.range.start.row
7954                && self.cursor.is_at_start_of_excerpt()
7955                && buffer_point.row > 0;
7956            let needs_expand_down = (region.excerpt.has_trailing_newline
7957                && self.point.row + 1 == region.range.end.row
7958                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7959                && self.cursor.is_at_end_of_excerpt()
7960                && buffer_point.row < region.buffer.max_point().row;
7961
7962            if needs_expand_up && needs_expand_down {
7963                Some(ExpandExcerptDirection::UpAndDown)
7964            } else if needs_expand_up {
7965                Some(ExpandExcerptDirection::Up)
7966            } else if needs_expand_down {
7967                Some(ExpandExcerptDirection::Down)
7968            } else {
7969                None
7970            }
7971            .map(|direction| ExpandInfo {
7972                direction,
7973                excerpt_id: region.excerpt.id,
7974            })
7975        };
7976
7977        let result = Some(RowInfo {
7978            buffer_id: Some(region.buffer.remote_id()),
7979            buffer_row: Some(buffer_point.row),
7980            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7981            diff_status: region
7982                .diff_hunk_status
7983                .filter(|_| self.point < region.range.end),
7984            expand_info,
7985            wrapped_buffer_row: None,
7986        });
7987        self.point += Point::new(1, 0);
7988        result
7989    }
7990}
7991
7992impl<'a> MultiBufferChunks<'a> {
7993    pub fn offset(&self) -> MultiBufferOffset {
7994        self.range.start
7995    }
7996
7997    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7998        self.diff_transforms.seek(&range.end, Bias::Right);
7999        let mut excerpt_end = self.diff_transforms.start().1;
8000        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8001            let overshoot = range.end - self.diff_transforms.start().0;
8002            excerpt_end += overshoot;
8003        }
8004
8005        self.diff_transforms.seek(&range.start, Bias::Right);
8006        let mut excerpt_start = self.diff_transforms.start().1;
8007        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8008            let overshoot = range.start - self.diff_transforms.start().0;
8009            excerpt_start += overshoot;
8010        }
8011
8012        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8013        self.buffer_chunk.take();
8014        self.range = range;
8015    }
8016
8017    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8018        self.excerpt_offset_range = new_range.clone();
8019        self.excerpts.seek(&new_range.start, Bias::Right);
8020        if let Some(excerpt) = self.excerpts.item() {
8021            let excerpt_start = *self.excerpts.start();
8022            if let Some(excerpt_chunks) = self
8023                .excerpt_chunks
8024                .as_mut()
8025                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8026            {
8027                excerpt.seek_chunks(
8028                    excerpt_chunks,
8029                    (self.excerpt_offset_range.start - excerpt_start)
8030                        ..(self.excerpt_offset_range.end - excerpt_start),
8031                );
8032            } else {
8033                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8034                    (self.excerpt_offset_range.start - excerpt_start)
8035                        ..(self.excerpt_offset_range.end - excerpt_start),
8036                    self.language_aware,
8037                ));
8038            }
8039        } else {
8040            self.excerpt_chunks = None;
8041        }
8042    }
8043
8044    #[ztracing::instrument(skip_all)]
8045    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8046        loop {
8047            if self.excerpt_offset_range.is_empty() {
8048                return None;
8049            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8050                self.excerpt_offset_range.start += chunk.text.len();
8051                return Some(chunk);
8052            } else {
8053                self.excerpts.next();
8054                let excerpt = self.excerpts.item()?;
8055                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8056                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8057                    self.language_aware,
8058                ));
8059            }
8060        }
8061    }
8062}
8063
8064impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8065    type Item = &'a str;
8066
8067    fn next(&mut self) -> Option<Self::Item> {
8068        let mut region = self.cursor.region()?;
8069        if self.offset == region.range.start {
8070            self.cursor.prev();
8071            region = self.cursor.region()?;
8072            let start_overshoot = self.start.saturating_sub(region.range.start);
8073            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8074                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8075            ));
8076        }
8077
8078        if self.offset == region.range.end && region.has_trailing_newline {
8079            self.offset -= 1;
8080            Some("\n")
8081        } else {
8082            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8083            self.offset -= chunk.len();
8084            Some(chunk)
8085        }
8086    }
8087}
8088
8089impl<'a> Iterator for MultiBufferChunks<'a> {
8090    type Item = Chunk<'a>;
8091
8092    #[ztracing::instrument(skip_all)]
8093    fn next(&mut self) -> Option<Chunk<'a>> {
8094        if self.range.start >= self.range.end {
8095            return None;
8096        }
8097        if self.range.start == self.diff_transforms.end().0 {
8098            self.diff_transforms.next();
8099        }
8100
8101        let diff_transform_start = self.diff_transforms.start().0;
8102        let diff_transform_end = self.diff_transforms.end().0;
8103        debug_assert!(
8104            self.range.start < diff_transform_end,
8105            "{:?} < {:?} of ({1:?}..{2:?})",
8106            self.range.start,
8107            diff_transform_end,
8108            diff_transform_start
8109        );
8110
8111        let diff_transform = self.diff_transforms.item()?;
8112        match diff_transform {
8113            DiffTransform::BufferContent { .. } => {
8114                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8115                    chunk
8116                } else {
8117                    let chunk = self.next_excerpt_chunk().unwrap();
8118                    self.buffer_chunk.insert(chunk)
8119                };
8120
8121                let chunk_end = self.range.start + chunk.text.len();
8122                let diff_transform_end = diff_transform_end.min(self.range.end);
8123
8124                if diff_transform_end < chunk_end {
8125                    let split_idx = diff_transform_end - self.range.start;
8126                    let (before, after) = chunk.text.split_at(split_idx);
8127                    self.range.start = diff_transform_end;
8128                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8129                    let chars = chunk.chars & mask;
8130                    let tabs = chunk.tabs & mask;
8131
8132                    chunk.text = after;
8133                    chunk.chars = chunk.chars >> split_idx;
8134                    chunk.tabs = chunk.tabs >> split_idx;
8135
8136                    Some(Chunk {
8137                        text: before,
8138                        chars,
8139                        tabs,
8140                        ..chunk.clone()
8141                    })
8142                } else {
8143                    self.range.start = chunk_end;
8144                    self.buffer_chunk.take()
8145                }
8146            }
8147            DiffTransform::DeletedHunk {
8148                buffer_id,
8149                base_text_byte_range,
8150                has_trailing_newline,
8151                ..
8152            } => {
8153                let base_text_start =
8154                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8155                let base_text_end =
8156                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8157                let base_text_end = base_text_end.min(base_text_byte_range.end);
8158
8159                let mut chunks = if let Some((_, mut chunks)) = self
8160                    .diff_base_chunks
8161                    .take()
8162                    .filter(|(id, _)| id == buffer_id)
8163                {
8164                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8165                    {
8166                        chunks.seek(base_text_start..base_text_end);
8167                    }
8168                    chunks
8169                } else {
8170                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8171                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8172                };
8173
8174                let chunk = if let Some(chunk) = chunks.next() {
8175                    self.range.start += chunk.text.len();
8176                    self.diff_base_chunks = Some((*buffer_id, chunks));
8177                    chunk
8178                } else {
8179                    debug_assert!(has_trailing_newline);
8180                    self.range.start += "\n".len();
8181                    Chunk {
8182                        text: "\n",
8183                        chars: 1u128,
8184                        ..Default::default()
8185                    }
8186                };
8187                Some(chunk)
8188            }
8189        }
8190    }
8191}
8192
8193impl MultiBufferBytes<'_> {
8194    fn consume(&mut self, len: usize) {
8195        self.range.start += len;
8196        self.chunk = &self.chunk[len..];
8197
8198        if !self.range.is_empty() && self.chunk.is_empty() {
8199            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8200                self.chunk = chunk;
8201            } else if self.has_trailing_newline {
8202                self.has_trailing_newline = false;
8203                self.chunk = b"\n";
8204            } else {
8205                self.cursor.next();
8206                if let Some(region) = self.cursor.region() {
8207                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8208                        region.buffer_range.start
8209                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8210                                .min(region.buffer_range.end),
8211                    );
8212                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8213                    self.excerpt_bytes = Some(excerpt_bytes);
8214                    self.has_trailing_newline =
8215                        region.has_trailing_newline && self.range.end >= region.range.end;
8216                    if self.chunk.is_empty() && self.has_trailing_newline {
8217                        self.has_trailing_newline = false;
8218                        self.chunk = b"\n";
8219                    }
8220                }
8221            }
8222        }
8223    }
8224}
8225
8226impl<'a> Iterator for MultiBufferBytes<'a> {
8227    type Item = &'a [u8];
8228
8229    fn next(&mut self) -> Option<Self::Item> {
8230        let chunk = self.chunk;
8231        if chunk.is_empty() {
8232            None
8233        } else {
8234            self.consume(chunk.len());
8235            Some(chunk)
8236        }
8237    }
8238}
8239
8240impl io::Read for MultiBufferBytes<'_> {
8241    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8242        let len = cmp::min(buf.len(), self.chunk.len());
8243        buf[..len].copy_from_slice(&self.chunk[..len]);
8244        if len > 0 {
8245            self.consume(len);
8246        }
8247        Ok(len)
8248    }
8249}
8250
8251impl io::Read for ReversedMultiBufferBytes<'_> {
8252    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8253        let len = cmp::min(buf.len(), self.chunk.len());
8254        buf[..len].copy_from_slice(&self.chunk[..len]);
8255        buf[..len].reverse();
8256        if len > 0 {
8257            self.range.end -= len;
8258            self.chunk = &self.chunk[..self.chunk.len() - len];
8259            if !self.range.is_empty()
8260                && self.chunk.is_empty()
8261                && let Some(chunk) = self.chunks.next()
8262            {
8263                self.chunk = chunk.as_bytes();
8264            }
8265        }
8266        Ok(len)
8267    }
8268}
8269
8270impl<'a> Iterator for ExcerptChunks<'a> {
8271    type Item = Chunk<'a>;
8272
8273    fn next(&mut self) -> Option<Self::Item> {
8274        if let Some(chunk) = self.content_chunks.next() {
8275            return Some(chunk);
8276        }
8277
8278        if self.has_footer {
8279            let text = "\n";
8280            let chars = 0b1;
8281            self.has_footer = false;
8282            return Some(Chunk {
8283                text,
8284                chars,
8285                ..Default::default()
8286            });
8287        }
8288
8289        None
8290    }
8291}
8292
8293impl ToOffset for Point {
8294    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8295        snapshot.point_to_offset(*self)
8296    }
8297    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8298        snapshot.point_to_offset_utf16(*self)
8299    }
8300}
8301
8302impl ToOffset for MultiBufferOffset {
8303    #[track_caller]
8304    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8305        assert!(
8306            *self <= snapshot.len(),
8307            "offset {} is greater than the snapshot.len() {}",
8308            self.0,
8309            snapshot.len().0,
8310        );
8311        *self
8312    }
8313    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8314        snapshot.offset_to_offset_utf16(*self)
8315    }
8316}
8317
8318impl ToOffset for MultiBufferOffsetUtf16 {
8319    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8320        snapshot.offset_utf16_to_offset(*self)
8321    }
8322
8323    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8324        *self
8325    }
8326}
8327
8328impl ToOffset for PointUtf16 {
8329    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8330        snapshot.point_utf16_to_offset(*self)
8331    }
8332    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8333        snapshot.point_utf16_to_offset_utf16(*self)
8334    }
8335}
8336
8337impl ToPoint for MultiBufferOffset {
8338    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8339        snapshot.offset_to_point(*self)
8340    }
8341    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8342        snapshot.offset_to_point_utf16(*self)
8343    }
8344}
8345
8346impl ToPoint for Point {
8347    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8348        *self
8349    }
8350    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8351        snapshot.point_to_point_utf16(*self)
8352    }
8353}
8354
8355impl ToPoint for PointUtf16 {
8356    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8357        snapshot.point_utf16_to_point(*self)
8358    }
8359    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8360        *self
8361    }
8362}
8363
8364impl From<ExcerptId> for EntityId {
8365    fn from(id: ExcerptId) -> Self {
8366        EntityId::from(id.0 as u64)
8367    }
8368}
8369
8370#[cfg(debug_assertions)]
8371pub mod debug {
8372    use super::*;
8373
8374    pub trait ToMultiBufferDebugRanges {
8375        fn to_multi_buffer_debug_ranges(
8376            &self,
8377            snapshot: &MultiBufferSnapshot,
8378        ) -> Vec<Range<MultiBufferOffset>>;
8379    }
8380
8381    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8382        fn to_multi_buffer_debug_ranges(
8383            &self,
8384            snapshot: &MultiBufferSnapshot,
8385        ) -> Vec<Range<MultiBufferOffset>> {
8386            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8387        }
8388    }
8389
8390    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8391        fn to_multi_buffer_debug_ranges(
8392            &self,
8393            snapshot: &MultiBufferSnapshot,
8394        ) -> Vec<Range<MultiBufferOffset>> {
8395            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8396                .to_multi_buffer_debug_ranges(snapshot)
8397        }
8398    }
8399
8400    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8401        fn to_multi_buffer_debug_ranges(
8402            &self,
8403            snapshot: &MultiBufferSnapshot,
8404        ) -> Vec<Range<MultiBufferOffset>> {
8405            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8406        }
8407    }
8408
8409    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8410        fn to_multi_buffer_debug_ranges(
8411            &self,
8412            snapshot: &MultiBufferSnapshot,
8413        ) -> Vec<Range<MultiBufferOffset>> {
8414            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8415        }
8416    }
8417
8418    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8419        fn to_multi_buffer_debug_ranges(
8420            &self,
8421            snapshot: &MultiBufferSnapshot,
8422        ) -> Vec<Range<MultiBufferOffset>> {
8423            self.iter()
8424                .map(|item| {
8425                    let offset = item.to_offset(snapshot);
8426                    offset..offset
8427                })
8428                .collect()
8429        }
8430    }
8431
8432    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8433        fn to_multi_buffer_debug_ranges(
8434            &self,
8435            snapshot: &MultiBufferSnapshot,
8436        ) -> Vec<Range<MultiBufferOffset>> {
8437            self.iter()
8438                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8439                .collect()
8440        }
8441    }
8442}