multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp::{self, Ordering},
  40    fmt,
  41    future::Future,
  42    io,
  43    iter::{self, FromIterator},
  44    mem,
  45    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  46    rc::Rc,
  47    str,
  48    sync::{Arc, OnceLock},
  49    time::Duration,
  50};
  51use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  52use text::{
  53    BufferId, Edit, LineIndent, TextSummary,
  54    locator::Locator,
  55    subscription::{Subscription, Topic},
  56};
  57use theme::SyntaxTheme;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68/// One or more [`Buffers`](Buffer) being edited in a single view.
  69///
  70/// See <https://zed.dev/features#multi-buffers>
  71pub struct MultiBuffer {
  72    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  73    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  74    snapshot: RefCell<MultiBufferSnapshot>,
  75    /// Contains the state of the buffers being edited
  76    buffers: BTreeMap<BufferId, BufferState>,
  77    /// Mapping from buffer IDs to their diff states
  78    diffs: HashMap<BufferId, DiffState>,
  79    subscriptions: Topic<MultiBufferOffset>,
  80    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  81    singleton: bool,
  82    /// The history of the multi-buffer.
  83    history: History,
  84    /// The explicit title of the multi-buffer.
  85    /// If `None`, it will be derived from the underlying path or content.
  86    title: Option<String>,
  87    /// The writing capability of the multi-buffer.
  88    capability: Capability,
  89    buffer_changed_since_sync: Rc<Cell<bool>>,
  90}
  91
  92pub struct ExcerptInfo {
  93    path_key: PathKey,
  94    buffer_id: BufferId,
  95    range: ExcerptRange<text::Anchor>,
  96}
  97
  98#[derive(Clone, Debug, PartialEq, Eq)]
  99pub enum Event {
 100    BufferUpdated {
 101        buffer: Entity<Buffer>,
 102        path_key: PathKey,
 103        ranges: Vec<Range<text::Anchor>>,
 104    },
 105    BuffersRemoved {
 106        removed_buffer_ids: Vec<BufferId>,
 107    },
 108    BuffersEdited {
 109        buffer_ids: Vec<BufferId>,
 110    },
 111    DiffHunksToggled,
 112    Edited {
 113        edited_buffer: Option<Entity<Buffer>>,
 114    },
 115    TransactionUndone {
 116        transaction_id: TransactionId,
 117    },
 118    Reloaded,
 119    LanguageChanged(BufferId, bool),
 120    Reparsed(BufferId),
 121    Saved,
 122    FileHandleChanged,
 123    DirtyChanged,
 124    DiagnosticsUpdated,
 125    BufferDiffChanged,
 126}
 127
 128/// A diff hunk, representing a range of consequent lines in a multibuffer.
 129#[derive(Debug, Clone, PartialEq, Eq)]
 130pub struct MultiBufferDiffHunk {
 131    /// The row range in the multibuffer where this diff hunk appears.
 132    pub row_range: Range<MultiBufferRow>,
 133    /// The buffer ID that this hunk belongs to.
 134    pub buffer_id: BufferId,
 135    /// The range of the underlying buffer that this hunk corresponds to.
 136    pub buffer_range: Range<text::Anchor>,
 137    /// The range within the buffer's diff base that this hunk corresponds to.
 138    pub diff_base_byte_range: Range<BufferOffset>,
 139    /// The status of this hunk (added/modified/deleted and secondary status).
 140    pub status: DiffHunkStatus,
 141    /// The word diffs for this hunk.
 142    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 143}
 144
 145impl MultiBufferDiffHunk {
 146    pub fn status(&self) -> DiffHunkStatus {
 147        self.status
 148    }
 149
 150    pub fn is_created_file(&self) -> bool {
 151        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 152            && self.buffer_range.start.is_min()
 153            && self.buffer_range.end.is_max()
 154    }
 155
 156    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 157        let start = Anchor::text(self.buffer_range.start);
 158        let end = Anchor::text(self.buffer_range.end);
 159        start..end
 160    }
 161}
 162
 163pub type MultiBufferPoint = Point;
 164type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 165type ExcerptPoint = ExcerptDimension<Point>;
 166
 167#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 168#[serde(transparent)]
 169pub struct MultiBufferRow(pub u32);
 170
 171impl MultiBufferRow {
 172    pub const MIN: Self = Self(0);
 173    pub const MAX: Self = Self(u32::MAX);
 174}
 175
 176impl ops::Add<usize> for MultiBufferRow {
 177    type Output = Self;
 178
 179    fn add(self, rhs: usize) -> Self::Output {
 180        MultiBufferRow(self.0 + rhs as u32)
 181    }
 182}
 183
 184pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 185    type TextDimension: TextDimension;
 186    fn from_summary(summary: &MBTextSummary) -> Self;
 187
 188    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 189
 190    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 191}
 192
 193// todo(lw): MultiBufferPoint
 194impl MultiBufferDimension for Point {
 195    type TextDimension = Point;
 196    fn from_summary(summary: &MBTextSummary) -> Self {
 197        summary.lines
 198    }
 199
 200    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 201        *self += *other;
 202    }
 203
 204    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 205        *self += summary.lines;
 206    }
 207}
 208
 209// todo(lw): MultiBufferPointUtf16
 210impl MultiBufferDimension for PointUtf16 {
 211    type TextDimension = PointUtf16;
 212    fn from_summary(summary: &MBTextSummary) -> Self {
 213        summary.lines_utf16()
 214    }
 215
 216    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 217        *self += *other;
 218    }
 219
 220    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 221        *self += summary.lines_utf16();
 222    }
 223}
 224
 225#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 226pub struct MultiBufferOffset(pub usize);
 227
 228impl fmt::Display for MultiBufferOffset {
 229    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 230        write!(f, "{}", self.0)
 231    }
 232}
 233
 234impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 235    type Sampler = MultiBufferOffsetUniformSampler;
 236}
 237
 238pub struct MultiBufferOffsetUniformSampler {
 239    sampler: rand::distr::uniform::UniformUsize,
 240}
 241
 242impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 243    type X = MultiBufferOffset;
 244
 245    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 246    where
 247        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 248        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 249    {
 250        let low = *low_b.borrow();
 251        let high = *high_b.borrow();
 252        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 253        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 254    }
 255
 256    #[inline] // if the range is constant, this helps LLVM to do the
 257    // calculations at compile-time.
 258    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 259    where
 260        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 261        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 262    {
 263        let low = *low_b.borrow();
 264        let high = *high_b.borrow();
 265        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 266        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 267    }
 268
 269    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 270        MultiBufferOffset(self.sampler.sample(rng))
 271    }
 272}
 273impl MultiBufferDimension for MultiBufferOffset {
 274    type TextDimension = usize;
 275    fn from_summary(summary: &MBTextSummary) -> Self {
 276        summary.len
 277    }
 278
 279    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 280        self.0 += *other;
 281    }
 282
 283    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 284        *self += summary.len;
 285    }
 286}
 287impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 288    type TextDimension = OffsetUtf16;
 289    fn from_summary(summary: &MBTextSummary) -> Self {
 290        MultiBufferOffsetUtf16(summary.len_utf16)
 291    }
 292
 293    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 294        self.0 += *other;
 295    }
 296
 297    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 298        self.0 += summary.len_utf16;
 299    }
 300}
 301
 302#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 303pub struct BufferOffset(pub usize);
 304
 305impl TextDimension for BufferOffset {
 306    fn from_text_summary(summary: &TextSummary) -> Self {
 307        BufferOffset(usize::from_text_summary(summary))
 308    }
 309    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 310        BufferOffset(usize::from_chunk(chunk))
 311    }
 312    fn add_assign(&mut self, other: &Self) {
 313        TextDimension::add_assign(&mut self.0, &other.0);
 314    }
 315}
 316impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 317    fn zero(cx: ()) -> Self {
 318        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 319    }
 320
 321    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 322        usize::add_summary(&mut self.0, summary, cx);
 323    }
 324}
 325
 326impl Sub for BufferOffset {
 327    type Output = usize;
 328
 329    fn sub(self, other: BufferOffset) -> Self::Output {
 330        self.0 - other.0
 331    }
 332}
 333
 334impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 335    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 336        self.0 += other.key;
 337    }
 338}
 339
 340impl language::ToPoint for BufferOffset {
 341    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 342        self.0.to_point(snapshot)
 343    }
 344}
 345
 346impl language::ToPointUtf16 for BufferOffset {
 347    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 348        self.0.to_point_utf16(snapshot)
 349    }
 350}
 351
 352impl language::ToOffset for BufferOffset {
 353    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 354        self.0.to_offset(snapshot)
 355    }
 356}
 357
 358impl language::ToOffsetUtf16 for BufferOffset {
 359    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 360        self.0.to_offset_utf16(snapshot)
 361    }
 362}
 363
 364#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 365pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 366
 367impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 368    type Output = MultiBufferOffsetUtf16;
 369
 370    fn add(self, rhs: usize) -> Self::Output {
 371        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 372    }
 373}
 374
 375impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 376    type Output = Self;
 377
 378    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 379        MultiBufferOffsetUtf16(self.0 + rhs)
 380    }
 381}
 382
 383impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    fn add_assign(&mut self, rhs: OffsetUtf16) {
 385        self.0 += rhs;
 386    }
 387}
 388
 389impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 390    fn add_assign(&mut self, rhs: usize) {
 391        self.0.0 += rhs;
 392    }
 393}
 394
 395impl Sub for MultiBufferOffsetUtf16 {
 396    type Output = OffsetUtf16;
 397
 398    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 399        self.0 - other.0
 400    }
 401}
 402
 403impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 404    type Output = MultiBufferOffsetUtf16;
 405
 406    fn sub(self, other: OffsetUtf16) -> Self::Output {
 407        MultiBufferOffsetUtf16(self.0 - other)
 408    }
 409}
 410
 411#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 412pub struct BufferOffsetUtf16(pub OffsetUtf16);
 413
 414impl MultiBufferOffset {
 415    const ZERO: Self = Self(0);
 416    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 417        self.0.saturating_sub(other.0)
 418    }
 419    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 420        MultiBufferOffset(self.0.saturating_sub(other))
 421    }
 422}
 423
 424impl ops::Sub for MultiBufferOffset {
 425    type Output = usize;
 426
 427    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 428        self.0 - other.0
 429    }
 430}
 431
 432impl ops::Sub<usize> for MultiBufferOffset {
 433    type Output = Self;
 434
 435    fn sub(self, other: usize) -> Self::Output {
 436        MultiBufferOffset(self.0 - other)
 437    }
 438}
 439
 440impl ops::SubAssign<usize> for MultiBufferOffset {
 441    fn sub_assign(&mut self, other: usize) {
 442        self.0 -= other;
 443    }
 444}
 445
 446impl ops::Add<usize> for BufferOffset {
 447    type Output = Self;
 448
 449    fn add(self, rhs: usize) -> Self::Output {
 450        BufferOffset(self.0 + rhs)
 451    }
 452}
 453
 454impl ops::AddAssign<usize> for BufferOffset {
 455    fn add_assign(&mut self, other: usize) {
 456        self.0 += other;
 457    }
 458}
 459
 460impl ops::Add<usize> for MultiBufferOffset {
 461    type Output = Self;
 462
 463    fn add(self, rhs: usize) -> Self::Output {
 464        MultiBufferOffset(self.0 + rhs)
 465    }
 466}
 467
 468impl ops::AddAssign<usize> for MultiBufferOffset {
 469    fn add_assign(&mut self, other: usize) {
 470        self.0 += other;
 471    }
 472}
 473
 474impl ops::Add<isize> for MultiBufferOffset {
 475    type Output = Self;
 476
 477    fn add(self, rhs: isize) -> Self::Output {
 478        MultiBufferOffset((self.0 as isize + rhs) as usize)
 479    }
 480}
 481
 482impl ops::Add for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 486        MultiBufferOffset(self.0 + rhs.0)
 487    }
 488}
 489
 490impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 491    fn add_assign(&mut self, other: MultiBufferOffset) {
 492        self.0 += other.0;
 493    }
 494}
 495
 496pub trait ToOffset: 'static + fmt::Debug {
 497    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 498    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 499}
 500
 501pub trait ToPoint: 'static + fmt::Debug {
 502    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 503    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 504}
 505
 506struct BufferState {
 507    buffer: Entity<Buffer>,
 508    last_version: RefCell<clock::Global>,
 509    last_non_text_state_update_count: Cell<usize>,
 510    _subscriptions: [gpui::Subscription; 2],
 511}
 512
 513struct DiffState {
 514    diff: Entity<BufferDiff>,
 515    main_buffer: Option<Entity<language::Buffer>>,
 516    _subscription: gpui::Subscription,
 517}
 518
 519impl DiffState {
 520    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 521        DiffStateSnapshot {
 522            diff: self.diff.read(cx).snapshot(cx),
 523            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 524        }
 525    }
 526}
 527
 528#[derive(Clone)]
 529struct DiffStateSnapshot {
 530    diff: BufferDiffSnapshot,
 531    main_buffer: Option<language::BufferSnapshot>,
 532}
 533
 534impl std::ops::Deref for DiffStateSnapshot {
 535    type Target = BufferDiffSnapshot;
 536
 537    fn deref(&self) -> &Self::Target {
 538        &self.diff
 539    }
 540}
 541
 542impl DiffState {
 543    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 544        DiffState {
 545            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 546                BufferDiffEvent::DiffChanged(DiffChanged {
 547                    changed_range,
 548                    base_text_changed_range: _,
 549                    extended_range,
 550                }) => {
 551                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 552                    let range = if use_extended {
 553                        extended_range.clone()
 554                    } else {
 555                        changed_range.clone()
 556                    };
 557                    if let Some(range) = range {
 558                        this.buffer_diff_changed(diff, range, cx)
 559                    }
 560                    cx.emit(Event::BufferDiffChanged);
 561                }
 562                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 563                _ => {}
 564            }),
 565            diff,
 566            main_buffer: None,
 567        }
 568    }
 569
 570    fn new_inverted(
 571        diff: Entity<BufferDiff>,
 572        main_buffer: Entity<language::Buffer>,
 573        cx: &mut Context<MultiBuffer>,
 574    ) -> Self {
 575        let weak_main_buffer = main_buffer.downgrade();
 576        DiffState {
 577            _subscription: cx.subscribe(&diff, {
 578                move |this, diff, event, cx| {
 579                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 580                        return;
 581                    };
 582                    match event {
 583                        BufferDiffEvent::DiffChanged(DiffChanged {
 584                            changed_range: _,
 585                            base_text_changed_range,
 586                            extended_range: _,
 587                        }) => {
 588                            this.inverted_buffer_diff_changed(
 589                                diff,
 590                                main_buffer,
 591                                base_text_changed_range.clone(),
 592                                cx,
 593                            );
 594                            cx.emit(Event::BufferDiffChanged);
 595                        }
 596                        BufferDiffEvent::LanguageChanged => {
 597                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 598                        }
 599                        _ => {}
 600                    }
 601                }
 602            }),
 603            diff,
 604            main_buffer: Some(main_buffer),
 605        }
 606    }
 607}
 608
 609/// The contents of a [`MultiBuffer`] at a single point in time.
 610#[derive(Clone, Default)]
 611pub struct MultiBufferSnapshot {
 612    excerpts: SumTree<Excerpt>,
 613    path_keys: TreeMap<BufferId, PathKey>,
 614    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 615    diff_transforms: SumTree<DiffTransform>,
 616    non_text_state_update_count: usize,
 617    edit_count: usize,
 618    is_dirty: bool,
 619    has_deleted_file: bool,
 620    has_conflict: bool,
 621    has_inverted_diff: bool,
 622    singleton: bool,
 623    trailing_excerpt_update_count: usize,
 624    all_diff_hunks_expanded: bool,
 625    show_deleted_hunks: bool,
 626    use_extended_diff_range: bool,
 627    show_headers: bool,
 628}
 629
 630#[derive(Debug, Clone)]
 631enum DiffTransform {
 632    BufferContent {
 633        summary: MBTextSummary,
 634        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 635    },
 636    DeletedHunk {
 637        summary: TextSummary,
 638        buffer_id: BufferId,
 639        hunk_info: DiffTransformHunkInfo,
 640        base_text_byte_range: Range<usize>,
 641        has_trailing_newline: bool,
 642    },
 643}
 644
 645#[derive(Clone, Copy, Debug)]
 646struct DiffTransformHunkInfo {
 647    buffer_id: BufferId,
 648    hunk_start_anchor: text::Anchor,
 649    hunk_secondary_status: DiffHunkSecondaryStatus,
 650    is_logically_deleted: bool,
 651}
 652
 653impl Eq for DiffTransformHunkInfo {}
 654
 655impl PartialEq for DiffTransformHunkInfo {
 656    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 657        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 658    }
 659}
 660
 661impl std::hash::Hash for DiffTransformHunkInfo {
 662    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 663        self.buffer_id.hash(state);
 664        self.hunk_start_anchor.hash(state);
 665    }
 666}
 667
 668#[derive(Clone)]
 669pub struct ExcerptBoundaryInfo {
 670    pub buffer: Arc<BufferSnapshot>,
 671    pub buffer_id: BufferId,
 672    pub range: ExcerptRange<text::Anchor>,
 673    pub end_row: MultiBufferRow,
 674}
 675
 676impl std::fmt::Debug for ExcerptBoundaryInfo {
 677    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 678        f.debug_struct(type_name::<Self>())
 679            .field("buffer_id", &self.buffer_id)
 680            .field("path", &self.buffer.file().map(|f| f.path()))
 681            .field("range", &self.range)
 682            .finish()
 683    }
 684}
 685
 686/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 687#[derive(Debug)]
 688pub struct ExcerptBoundary {
 689    pub prev: Option<ExcerptBoundaryInfo>,
 690    pub next: ExcerptBoundaryInfo,
 691    /// The row in the `MultiBuffer` where the boundary is located
 692    pub row: MultiBufferRow,
 693}
 694
 695impl ExcerptBoundary {
 696    pub fn starts_new_buffer(&self) -> bool {
 697        match (self.prev.as_ref(), &self.next) {
 698            (None, _) => true,
 699            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 700        }
 701    }
 702}
 703
 704#[derive(Clone, Debug, PartialEq, Eq)]
 705pub struct ExpandInfo {
 706    pub direction: ExpandExcerptDirection,
 707    pub excerpt_range: Range<text::Anchor>,
 708}
 709
 710#[derive(Clone, Debug, Default, PartialEq, Eq)]
 711pub struct RowInfo {
 712    pub buffer_id: Option<BufferId>,
 713    pub buffer_row: Option<u32>,
 714    pub multibuffer_row: Option<MultiBufferRow>,
 715    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 716    pub expand_info: Option<ExpandInfo>,
 717    pub wrapped_buffer_row: Option<u32>,
 718}
 719
 720/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 721#[derive(Clone)]
 722pub(crate) struct Excerpt {
 723    /// The location of the excerpt in the [`MultiBuffer`]
 724    pub(crate) path_key: PathKey,
 725    /// A snapshot of the buffer being excerpted
 726    pub(crate) buffer: Arc<BufferSnapshot>,
 727    /// The range of the buffer to be shown in the excerpt
 728    pub(crate) range: ExcerptRange<text::Anchor>,
 729
 730    /// The last row in the excerpted slice of the buffer
 731    pub(crate) max_buffer_row: BufferRow,
 732    /// A summary of the text in the excerpt
 733    pub(crate) text_summary: TextSummary,
 734    pub(crate) has_trailing_newline: bool,
 735}
 736
 737/// A public view into an `Excerpt` in a [`MultiBuffer`].
 738///
 739/// Contains methods for getting the [`Buffer`] of the excerpt,
 740/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 741#[derive(Clone)]
 742pub struct MultiBufferExcerpt<'a> {
 743    excerpt: &'a Excerpt,
 744    diff_transforms:
 745        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 746    /// The offset in the multibuffer considering diff transforms.
 747    offset: MultiBufferOffset,
 748    /// The offset in the multibuffer without diff transforms.
 749    excerpt_offset: ExcerptOffset,
 750    buffer_offset: BufferOffset,
 751}
 752
 753/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 754/// These ranges are relative to the buffer itself
 755#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 756pub struct ExcerptRange<T> {
 757    /// The full range of text to be shown in the excerpt.
 758    pub context: Range<T>,
 759    /// The primary range of text to be highlighted in the excerpt.
 760    /// In a multi-buffer search, this would be the text that matched the search
 761    pub primary: Range<T>,
 762}
 763
 764impl<T: Clone> ExcerptRange<T> {
 765    pub fn new(context: Range<T>) -> Self {
 766        Self {
 767            context: context.clone(),
 768            primary: context,
 769        }
 770    }
 771}
 772
 773impl ExcerptRange<text::Anchor> {
 774    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 775        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 776    }
 777}
 778
 779#[derive(Clone, Debug)]
 780pub struct ExcerptSummary {
 781    path_key: PathKey,
 782    /// End of the excerpt
 783    max_anchor: text::Anchor,
 784    widest_line_number: u32,
 785    text: MBTextSummary,
 786    count: usize,
 787}
 788
 789impl ExcerptSummary {
 790    pub fn min() -> Self {
 791        ExcerptSummary {
 792            path_key: PathKey::min(),
 793            max_anchor: text::Anchor::MIN,
 794            widest_line_number: 0,
 795            text: MBTextSummary::default(),
 796            count: 0,
 797        }
 798    }
 799}
 800
 801#[derive(Debug, Clone)]
 802pub struct DiffTransformSummary {
 803    input: MBTextSummary,
 804    output: MBTextSummary,
 805}
 806
 807/// Summary of a string of text.
 808#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 809pub struct MBTextSummary {
 810    /// Length in bytes.
 811    pub len: MultiBufferOffset,
 812    /// Length in UTF-8.
 813    pub chars: usize,
 814    /// Length in UTF-16 code units
 815    pub len_utf16: OffsetUtf16,
 816    /// A point representing the number of lines and the length of the last line.
 817    ///
 818    /// In other words, it marks the point after the last byte in the text, (if
 819    /// EOF was a character, this would be its position).
 820    pub lines: Point,
 821    /// How many `char`s are in the first line
 822    pub first_line_chars: u32,
 823    /// How many `char`s are in the last line
 824    pub last_line_chars: u32,
 825    /// How many UTF-16 code units are in the last line
 826    pub last_line_len_utf16: u32,
 827    /// The row idx of the longest row
 828    pub longest_row: u32,
 829    /// How many `char`s are in the longest row
 830    pub longest_row_chars: u32,
 831}
 832
 833impl From<TextSummary> for MBTextSummary {
 834    fn from(summary: TextSummary) -> Self {
 835        MBTextSummary {
 836            len: MultiBufferOffset(summary.len),
 837            chars: summary.chars,
 838            len_utf16: summary.len_utf16,
 839            lines: summary.lines,
 840            first_line_chars: summary.first_line_chars,
 841            last_line_chars: summary.last_line_chars,
 842            last_line_len_utf16: summary.last_line_len_utf16,
 843            longest_row: summary.longest_row,
 844            longest_row_chars: summary.longest_row_chars,
 845        }
 846    }
 847}
 848
 849impl From<MBTextSummary> for TextSummary {
 850    fn from(summary: MBTextSummary) -> Self {
 851        TextSummary {
 852            len: summary.len.0,
 853            chars: summary.chars,
 854            len_utf16: summary.len_utf16,
 855            lines: summary.lines,
 856            first_line_chars: summary.first_line_chars,
 857            last_line_chars: summary.last_line_chars,
 858            last_line_len_utf16: summary.last_line_len_utf16,
 859            longest_row: summary.longest_row,
 860            longest_row_chars: summary.longest_row_chars,
 861        }
 862    }
 863}
 864
 865impl From<&str> for MBTextSummary {
 866    fn from(text: &str) -> Self {
 867        MBTextSummary::from(TextSummary::from(text))
 868    }
 869}
 870
 871impl MultiBufferDimension for MBTextSummary {
 872    type TextDimension = TextSummary;
 873
 874    fn from_summary(summary: &MBTextSummary) -> Self {
 875        *summary
 876    }
 877
 878    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 879        *self += *summary;
 880    }
 881
 882    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 883        *self += *summary;
 884    }
 885}
 886
 887impl AddAssign for MBTextSummary {
 888    fn add_assign(&mut self, other: MBTextSummary) {
 889        let joined_chars = self.last_line_chars + other.first_line_chars;
 890        if joined_chars > self.longest_row_chars {
 891            self.longest_row = self.lines.row;
 892            self.longest_row_chars = joined_chars;
 893        }
 894        if other.longest_row_chars > self.longest_row_chars {
 895            self.longest_row = self.lines.row + other.longest_row;
 896            self.longest_row_chars = other.longest_row_chars;
 897        }
 898
 899        if self.lines.row == 0 {
 900            self.first_line_chars += other.first_line_chars;
 901        }
 902
 903        if other.lines.row == 0 {
 904            self.last_line_chars += other.first_line_chars;
 905            self.last_line_len_utf16 += other.last_line_len_utf16;
 906        } else {
 907            self.last_line_chars = other.last_line_chars;
 908            self.last_line_len_utf16 = other.last_line_len_utf16;
 909        }
 910
 911        self.chars += other.chars;
 912        self.len += other.len;
 913        self.len_utf16 += other.len_utf16;
 914        self.lines += other.lines;
 915    }
 916}
 917
 918impl AddAssign<TextSummary> for MBTextSummary {
 919    fn add_assign(&mut self, other: TextSummary) {
 920        *self += MBTextSummary::from(other);
 921    }
 922}
 923
 924impl MBTextSummary {
 925    pub fn lines_utf16(&self) -> PointUtf16 {
 926        PointUtf16 {
 927            row: self.lines.row,
 928            column: self.last_line_len_utf16,
 929        }
 930    }
 931}
 932
 933impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 934where
 935    K: MultiBufferDimension,
 936    V: MultiBufferDimension,
 937{
 938    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 939
 940    fn from_summary(summary: &MBTextSummary) -> Self {
 941        Self {
 942            key: K::from_summary(summary),
 943            value: Some(V::from_summary(summary)),
 944        }
 945    }
 946
 947    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 948        self.key.add_text_dim(&summary.key);
 949        if let Some(value) = &mut self.value {
 950            if let Some(other_value) = summary.value.as_ref() {
 951                value.add_text_dim(other_value);
 952            }
 953        }
 954    }
 955
 956    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 957        self.key.add_mb_text_summary(summary);
 958        if let Some(value) = &mut self.value {
 959            value.add_mb_text_summary(summary);
 960        }
 961    }
 962}
 963
 964#[derive(Clone)]
 965pub struct MultiBufferRows<'a> {
 966    point: Point,
 967    is_empty: bool,
 968    is_singleton: bool,
 969    cursor: MultiBufferCursor<'a, Point, Point>,
 970}
 971
 972pub struct MultiBufferChunks<'a> {
 973    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 974    diff_transforms:
 975        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 976    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 977    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 978    buffer_chunk: Option<Chunk<'a>>,
 979    range: Range<MultiBufferOffset>,
 980    excerpt_offset_range: Range<ExcerptOffset>,
 981    excerpt_chunks: Option<ExcerptChunks<'a>>,
 982    language_aware: bool,
 983}
 984
 985pub struct ReversedMultiBufferChunks<'a> {
 986    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 987    current_chunks: Option<rope::Chunks<'a>>,
 988    start: MultiBufferOffset,
 989    offset: MultiBufferOffset,
 990}
 991
 992pub struct MultiBufferBytes<'a> {
 993    range: Range<MultiBufferOffset>,
 994    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 995    excerpt_bytes: Option<text::Bytes<'a>>,
 996    has_trailing_newline: bool,
 997    chunk: &'a [u8],
 998}
 999
1000pub struct ReversedMultiBufferBytes<'a> {
1001    range: Range<MultiBufferOffset>,
1002    chunks: ReversedMultiBufferChunks<'a>,
1003    chunk: &'a [u8],
1004}
1005
1006#[derive(Clone)]
1007struct DiffTransforms<MBD> {
1008    output_dimension: OutputDimension<MBD>,
1009    excerpt_dimension: ExcerptDimension<MBD>,
1010}
1011
1012impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1013    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1014        Self {
1015            output_dimension: OutputDimension::zero(cx),
1016            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1017                cx,
1018            ),
1019        }
1020    }
1021
1022    fn add_summary(
1023        &mut self,
1024        summary: &'a DiffTransformSummary,
1025        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1026    ) {
1027        self.output_dimension.add_summary(summary, cx);
1028        self.excerpt_dimension.add_summary(summary, cx);
1029    }
1030}
1031
1032#[derive(Clone)]
1033struct MultiBufferCursor<'a, MBD, BD> {
1034    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1035    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1036    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1037    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1038}
1039
1040#[derive(Clone)]
1041struct MultiBufferRegion<'a, MBD, BD> {
1042    buffer: &'a BufferSnapshot,
1043    is_main_buffer: bool,
1044    diff_hunk_status: Option<DiffHunkStatus>,
1045    excerpt: &'a Excerpt,
1046    buffer_range: Range<BD>,
1047    range: Range<MBD>,
1048    has_trailing_newline: bool,
1049}
1050
1051struct ExcerptChunks<'a> {
1052    content_chunks: BufferChunks<'a>,
1053    has_footer: bool,
1054}
1055
1056#[derive(Debug)]
1057struct BufferEdit {
1058    range: Range<BufferOffset>,
1059    new_text: Arc<str>,
1060    is_insertion: bool,
1061    original_indent_column: Option<u32>,
1062}
1063
1064#[derive(Clone, Copy, Debug, PartialEq)]
1065enum DiffChangeKind {
1066    BufferEdited,
1067    DiffUpdated { base_changed: bool },
1068    ExpandOrCollapseHunks { expand: bool },
1069}
1070
1071#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1072pub enum ExpandExcerptDirection {
1073    Up,
1074    Down,
1075    UpAndDown,
1076}
1077
1078impl ExpandExcerptDirection {
1079    pub fn should_expand_up(&self) -> bool {
1080        match self {
1081            ExpandExcerptDirection::Up => true,
1082            ExpandExcerptDirection::Down => false,
1083            ExpandExcerptDirection::UpAndDown => true,
1084        }
1085    }
1086
1087    pub fn should_expand_down(&self) -> bool {
1088        match self {
1089            ExpandExcerptDirection::Up => false,
1090            ExpandExcerptDirection::Down => true,
1091            ExpandExcerptDirection::UpAndDown => true,
1092        }
1093    }
1094}
1095
1096#[derive(Clone, Debug, PartialEq)]
1097pub struct IndentGuide {
1098    pub buffer_id: BufferId,
1099    pub start_row: MultiBufferRow,
1100    pub end_row: MultiBufferRow,
1101    pub depth: u32,
1102    pub tab_size: u32,
1103    pub settings: IndentGuideSettings,
1104}
1105
1106impl IndentGuide {
1107    pub fn indent_level(&self) -> u32 {
1108        self.depth * self.tab_size
1109    }
1110}
1111
1112impl MultiBuffer {
1113    pub fn new(capability: Capability) -> Self {
1114        Self::new_(
1115            capability,
1116            MultiBufferSnapshot {
1117                show_headers: true,
1118                show_deleted_hunks: true,
1119                ..MultiBufferSnapshot::default()
1120            },
1121        )
1122    }
1123
1124    pub fn without_headers(capability: Capability) -> Self {
1125        Self::new_(
1126            capability,
1127            MultiBufferSnapshot {
1128                show_deleted_hunks: true,
1129                ..MultiBufferSnapshot::default()
1130            },
1131        )
1132    }
1133
1134    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1135        let mut this = Self::new_(
1136            buffer.read(cx).capability(),
1137            MultiBufferSnapshot {
1138                singleton: true,
1139                show_deleted_hunks: true,
1140                ..MultiBufferSnapshot::default()
1141            },
1142        );
1143        this.singleton = true;
1144        this.set_excerpts_for_path(
1145            PathKey::sorted(0),
1146            buffer.clone(),
1147            [Point::zero()..buffer.read(cx).max_point()],
1148            0,
1149            cx,
1150        );
1151        this
1152    }
1153
1154    #[inline]
1155    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1156        Self {
1157            snapshot: RefCell::new(snapshot),
1158            buffers: Default::default(),
1159            diffs: HashMap::default(),
1160            subscriptions: Topic::default(),
1161            singleton: false,
1162            capability,
1163            title: None,
1164            buffer_changed_since_sync: Default::default(),
1165            history: History::default(),
1166        }
1167    }
1168
1169    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1170        let mut buffers = BTreeMap::default();
1171        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1172        for (buffer_id, buffer_state) in self.buffers.iter() {
1173            buffer_state.buffer.update(new_cx, |buffer, _| {
1174                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1175            });
1176            buffers.insert(
1177                *buffer_id,
1178                BufferState {
1179                    buffer: buffer_state.buffer.clone(),
1180                    last_version: buffer_state.last_version.clone(),
1181                    last_non_text_state_update_count: buffer_state
1182                        .last_non_text_state_update_count
1183                        .clone(),
1184                    _subscriptions: [
1185                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1186                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1187                    ],
1188                },
1189            );
1190        }
1191        let mut diff_bases = HashMap::default();
1192        for (buffer_id, diff) in self.diffs.iter() {
1193            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1194        }
1195        Self {
1196            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1197            buffers,
1198            diffs: diff_bases,
1199            subscriptions: Default::default(),
1200            singleton: self.singleton,
1201            capability: self.capability,
1202            history: self.history.clone(),
1203            title: self.title.clone(),
1204            buffer_changed_since_sync,
1205        }
1206    }
1207
1208    pub fn set_group_interval(&mut self, group_interval: Duration) {
1209        self.history.set_group_interval(group_interval);
1210    }
1211
1212    pub fn with_title(mut self, title: String) -> Self {
1213        self.title = Some(title);
1214        self
1215    }
1216
1217    pub fn read_only(&self) -> bool {
1218        !self.capability.editable()
1219    }
1220
1221    pub fn capability(&self) -> Capability {
1222        self.capability
1223    }
1224
1225    /// Returns an up-to-date snapshot of the MultiBuffer.
1226    #[ztracing::instrument(skip_all)]
1227    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1228        self.sync(cx);
1229        self.snapshot.borrow().clone()
1230    }
1231
1232    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1233        self.sync(cx);
1234        self.snapshot.borrow()
1235    }
1236
1237    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1238        if self.singleton {
1239            Some(self.buffers.values().next().unwrap().buffer.clone())
1240        } else {
1241            None
1242        }
1243    }
1244
1245    pub fn is_singleton(&self) -> bool {
1246        self.singleton
1247    }
1248
1249    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1250        self.subscriptions.subscribe()
1251    }
1252
1253    pub fn is_dirty(&self, cx: &App) -> bool {
1254        self.read(cx).is_dirty()
1255    }
1256
1257    pub fn has_deleted_file(&self, cx: &App) -> bool {
1258        self.read(cx).has_deleted_file()
1259    }
1260
1261    pub fn has_conflict(&self, cx: &App) -> bool {
1262        self.read(cx).has_conflict()
1263    }
1264
1265    // The `is_empty` signature doesn't match what clippy expects
1266    #[allow(clippy::len_without_is_empty)]
1267    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1268        self.read(cx).len()
1269    }
1270
1271    pub fn is_empty(&self) -> bool {
1272        self.buffers.is_empty()
1273    }
1274
1275    pub fn edit<I, S, T>(
1276        &mut self,
1277        edits: I,
1278        autoindent_mode: Option<AutoindentMode>,
1279        cx: &mut Context<Self>,
1280    ) where
1281        I: IntoIterator<Item = (Range<S>, T)>,
1282        S: ToOffset,
1283        T: Into<Arc<str>>,
1284    {
1285        self.edit_internal(edits, autoindent_mode, true, cx);
1286    }
1287
1288    pub fn edit_non_coalesce<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, false, cx);
1299    }
1300
1301    fn edit_internal<I, S, T>(
1302        &mut self,
1303        edits: I,
1304        autoindent_mode: Option<AutoindentMode>,
1305        coalesce_adjacent: bool,
1306        cx: &mut Context<Self>,
1307    ) where
1308        I: IntoIterator<Item = (Range<S>, T)>,
1309        S: ToOffset,
1310        T: Into<Arc<str>>,
1311    {
1312        if self.read_only() || self.buffers.is_empty() {
1313            return;
1314        }
1315        self.sync_mut(cx);
1316        let edits = edits
1317            .into_iter()
1318            .map(|(range, new_text)| {
1319                let mut range = range.start.to_offset(self.snapshot.get_mut())
1320                    ..range.end.to_offset(self.snapshot.get_mut());
1321                if range.start > range.end {
1322                    mem::swap(&mut range.start, &mut range.end);
1323                }
1324                (range, new_text.into())
1325            })
1326            .collect::<Vec<_>>();
1327
1328        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1329
1330        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1331        fn edit_internal(
1332            this: &mut MultiBuffer,
1333            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1334            mut autoindent_mode: Option<AutoindentMode>,
1335            coalesce_adjacent: bool,
1336            cx: &mut Context<MultiBuffer>,
1337        ) {
1338            let original_indent_columns = match &mut autoindent_mode {
1339                Some(AutoindentMode::Block {
1340                    original_indent_columns,
1341                }) => mem::take(original_indent_columns),
1342                _ => Default::default(),
1343            };
1344
1345            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1346                edits,
1347                this.snapshot.get_mut(),
1348                &original_indent_columns,
1349            );
1350
1351            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1352            for (buffer_id, mut edits) in buffer_edits {
1353                buffer_ids.push(buffer_id);
1354                edits.sort_by_key(|edit| edit.range.start);
1355                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1356                    let mut edits = edits.into_iter().peekable();
1357                    let mut insertions = Vec::new();
1358                    let mut original_indent_columns = Vec::new();
1359                    let mut deletions = Vec::new();
1360                    let empty_str: Arc<str> = Arc::default();
1361                    while let Some(BufferEdit {
1362                        mut range,
1363                        mut new_text,
1364                        mut is_insertion,
1365                        original_indent_column,
1366                    }) = edits.next()
1367                    {
1368                        while let Some(BufferEdit {
1369                            range: next_range,
1370                            is_insertion: next_is_insertion,
1371                            new_text: next_new_text,
1372                            ..
1373                        }) = edits.peek()
1374                        {
1375                            let should_coalesce = if coalesce_adjacent {
1376                                range.end >= next_range.start
1377                            } else {
1378                                range.end > next_range.start
1379                            };
1380
1381                            if should_coalesce {
1382                                range.end = cmp::max(next_range.end, range.end);
1383                                is_insertion |= *next_is_insertion;
1384                                new_text = format!("{new_text}{next_new_text}").into();
1385                                edits.next();
1386                            } else {
1387                                break;
1388                            }
1389                        }
1390
1391                        if is_insertion {
1392                            original_indent_columns.push(original_indent_column);
1393                            insertions.push((
1394                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1395                                new_text.clone(),
1396                            ));
1397                        } else if !range.is_empty() {
1398                            deletions.push((
1399                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1400                                empty_str.clone(),
1401                            ));
1402                        }
1403                    }
1404
1405                    let deletion_autoindent_mode =
1406                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1407                            Some(AutoindentMode::Block {
1408                                original_indent_columns: Default::default(),
1409                            })
1410                        } else {
1411                            autoindent_mode.clone()
1412                        };
1413                    let insertion_autoindent_mode =
1414                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1415                            Some(AutoindentMode::Block {
1416                                original_indent_columns,
1417                            })
1418                        } else {
1419                            autoindent_mode.clone()
1420                        };
1421
1422                    if coalesce_adjacent {
1423                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1424                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1425                    } else {
1426                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1427                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1428                    }
1429                })
1430            }
1431
1432            cx.emit(Event::BuffersEdited { buffer_ids });
1433        }
1434    }
1435
1436    fn convert_edits_to_buffer_edits(
1437        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1438        snapshot: &MultiBufferSnapshot,
1439        original_indent_columns: &[Option<u32>],
1440    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1441        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1442        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1443        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1444            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1445
1446            cursor.seek(&range.start);
1447            let mut start_region = cursor.region().expect("start offset out of bounds");
1448            if !start_region.is_main_buffer {
1449                cursor.next();
1450                if let Some(region) = cursor.region() {
1451                    start_region = region;
1452                } else {
1453                    continue;
1454                }
1455            }
1456
1457            if range.end < start_region.range.start {
1458                continue;
1459            }
1460
1461            let start_region = start_region.clone();
1462            if range.end > start_region.range.end {
1463                cursor.seek_forward(&range.end);
1464            }
1465            let mut end_region = cursor.region().expect("end offset out of bounds");
1466            if !end_region.is_main_buffer {
1467                cursor.prev();
1468                if let Some(region) = cursor.region() {
1469                    end_region = region;
1470                } else {
1471                    continue;
1472                }
1473            }
1474
1475            if range.start > end_region.range.end {
1476                continue;
1477            }
1478
1479            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1480            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1481            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1482                .min(start_region.buffer_range.end);
1483            let buffer_end =
1484                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1485
1486            if start_region.excerpt == end_region.excerpt {
1487                if start_region.buffer.capability == Capability::ReadWrite
1488                    && start_region.is_main_buffer
1489                {
1490                    buffer_edits
1491                        .entry(start_region.buffer.remote_id())
1492                        .or_default()
1493                        .push(BufferEdit {
1494                            range: buffer_start..buffer_end,
1495                            new_text,
1496                            is_insertion: true,
1497                            original_indent_column,
1498                        });
1499                }
1500            } else {
1501                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1502                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1503                if start_region.buffer.capability == Capability::ReadWrite
1504                    && start_region.is_main_buffer
1505                {
1506                    buffer_edits
1507                        .entry(start_region.buffer.remote_id())
1508                        .or_default()
1509                        .push(BufferEdit {
1510                            range: start_excerpt_range,
1511                            new_text: new_text.clone(),
1512                            is_insertion: true,
1513                            original_indent_column,
1514                        });
1515                }
1516                if end_region.buffer.capability == Capability::ReadWrite
1517                    && end_region.is_main_buffer
1518                {
1519                    buffer_edits
1520                        .entry(end_region.buffer.remote_id())
1521                        .or_default()
1522                        .push(BufferEdit {
1523                            range: end_excerpt_range,
1524                            new_text: new_text.clone(),
1525                            is_insertion: false,
1526                            original_indent_column,
1527                        });
1528                }
1529                let end_region_excerpt = end_region.excerpt.clone();
1530
1531                cursor.seek(&range.start);
1532                cursor.next_excerpt();
1533                while let Some(region) = cursor.region() {
1534                    if region.excerpt == &end_region_excerpt {
1535                        break;
1536                    }
1537                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1538                        buffer_edits
1539                            .entry(region.buffer.remote_id())
1540                            .or_default()
1541                            .push(BufferEdit {
1542                                range: region.buffer_range.clone(),
1543                                new_text: new_text.clone(),
1544                                is_insertion: false,
1545                                original_indent_column,
1546                            });
1547                    }
1548                    cursor.next_excerpt();
1549                }
1550            }
1551        }
1552        buffer_edits
1553    }
1554
1555    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1556    where
1557        I: IntoIterator<Item = Range<S>>,
1558        S: ToOffset,
1559    {
1560        if self.read_only() || self.buffers.is_empty() {
1561            return;
1562        }
1563        self.sync_mut(cx);
1564        let empty = Arc::<str>::from("");
1565        let edits = ranges
1566            .into_iter()
1567            .map(|range| {
1568                let mut range = range.start.to_offset(self.snapshot.get_mut())
1569                    ..range.end.to_offset(&self.snapshot.get_mut());
1570                if range.start > range.end {
1571                    mem::swap(&mut range.start, &mut range.end);
1572                }
1573                (range, empty.clone())
1574            })
1575            .collect::<Vec<_>>();
1576
1577        return autoindent_ranges_internal(self, edits, cx);
1578
1579        fn autoindent_ranges_internal(
1580            this: &mut MultiBuffer,
1581            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1582            cx: &mut Context<MultiBuffer>,
1583        ) {
1584            let buffer_edits =
1585                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1586
1587            let mut buffer_ids = Vec::new();
1588            for (buffer_id, mut edits) in buffer_edits {
1589                buffer_ids.push(buffer_id);
1590                edits.sort_unstable_by_key(|edit| edit.range.start);
1591
1592                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1593                for edit in edits {
1594                    if let Some(last_range) = ranges.last_mut()
1595                        && edit.range.start <= last_range.end
1596                    {
1597                        last_range.end = last_range.end.max(edit.range.end);
1598                        continue;
1599                    }
1600                    ranges.push(edit.range);
1601                }
1602
1603                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1604                    buffer.autoindent_ranges(ranges, cx);
1605                })
1606            }
1607
1608            cx.emit(Event::BuffersEdited { buffer_ids });
1609        }
1610    }
1611
1612    pub fn set_active_selections(
1613        &self,
1614        selections: &[Selection<Anchor>],
1615        line_mode: bool,
1616        cursor_shape: CursorShape,
1617        cx: &mut Context<Self>,
1618    ) {
1619        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1620            Default::default();
1621        let snapshot = self.read(cx);
1622        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1623        for selection in selections {
1624            let Some(start) = snapshot.anchor_seek_target(selection.start) else {
1625                continue;
1626            };
1627            let Some(end) = snapshot.anchor_seek_target(selection.end) else {
1628                continue;
1629            };
1630
1631            cursor.seek(&start, Bias::Left);
1632            while let Some(excerpt) = cursor.item()
1633                && sum_tree::SeekTarget::cmp(&end, &cursor.position, ()).is_gt()
1634            {
1635                let start = text::Anchor::max(
1636                    &excerpt.range.context.start,
1637                    &selection.start.text_anchor().unwrap_or(text::Anchor::MIN),
1638                    &excerpt.buffer,
1639                )
1640                .clone();
1641                let end = text::Anchor::min(
1642                    &excerpt.range.context.end,
1643                    &selection.end.text_anchor().unwrap_or(text::Anchor::MAX),
1644                    &excerpt.buffer,
1645                )
1646                .clone();
1647                selections_by_buffer
1648                    .entry(excerpt.buffer.remote_id())
1649                    .or_default()
1650                    .push(Selection {
1651                        id: selection.id,
1652                        start,
1653                        end,
1654                        reversed: selection.reversed,
1655                        goal: selection.goal,
1656                    });
1657
1658                cursor.next();
1659            }
1660        }
1661
1662        for (buffer_id, buffer_state) in self.buffers.iter() {
1663            if !selections_by_buffer.contains_key(buffer_id) {
1664                buffer_state
1665                    .buffer
1666                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1667            }
1668        }
1669
1670        for (buffer_id, selections) in selections_by_buffer {
1671            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1672                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1673            });
1674        }
1675    }
1676
1677    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1678        for buffer in self.buffers.values() {
1679            buffer
1680                .buffer
1681                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1682        }
1683    }
1684
1685    #[instrument(skip_all)]
1686    fn merge_excerpt_ranges<'a>(
1687        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1688    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1689        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1690        let mut counts: Vec<usize> = Vec::new();
1691        for range in expanded_ranges {
1692            if let Some(last_range) = merged_ranges.last_mut() {
1693                assert!(
1694                    last_range.context.start <= range.context.start,
1695                    "ranges must be sorted: {last_range:?} <= {range:?}"
1696                );
1697                if last_range.context.end >= range.context.start
1698                    || last_range.context.end.row + 1 == range.context.start.row
1699                {
1700                    last_range.context.end = range.context.end.max(last_range.context.end);
1701                    *counts.last_mut().unwrap() += 1;
1702                    continue;
1703                }
1704            }
1705            merged_ranges.push(range.clone());
1706            counts.push(1);
1707        }
1708        (merged_ranges, counts)
1709    }
1710
1711    pub fn clear(&mut self, cx: &mut Context<Self>) {
1712        self.sync_mut(cx);
1713        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1714        let MultiBufferSnapshot {
1715            excerpts,
1716            diffs: _,
1717            diff_transforms: _,
1718            non_text_state_update_count: _,
1719            edit_count: _,
1720            is_dirty,
1721            has_deleted_file,
1722            has_conflict,
1723            has_inverted_diff,
1724            singleton: _,
1725            trailing_excerpt_update_count,
1726            all_diff_hunks_expanded: _,
1727            show_deleted_hunks: _,
1728            use_extended_diff_range: _,
1729            show_headers: _,
1730            path_keys: _,
1731        } = self.snapshot.get_mut();
1732        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1733        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1734        *excerpts = Default::default();
1735        *trailing_excerpt_update_count += 1;
1736        *is_dirty = false;
1737        *has_deleted_file = false;
1738        *has_conflict = false;
1739        *has_inverted_diff = false;
1740
1741        let edits = Self::sync_diff_transforms(
1742            self.snapshot.get_mut(),
1743            vec![Edit {
1744                old: start..prev_len,
1745                new: start..start,
1746            }],
1747            DiffChangeKind::BufferEdited,
1748        );
1749        if !edits.is_empty() {
1750            self.subscriptions.publish(edits);
1751        }
1752        cx.emit(Event::Edited {
1753            edited_buffer: None,
1754        });
1755        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1756        cx.notify();
1757    }
1758
1759    #[ztracing::instrument(skip_all)]
1760    pub fn excerpts_for_buffer(
1761        &self,
1762        buffer_id: BufferId,
1763        cx: &App,
1764    ) -> Vec<ExcerptRange<text::Anchor>> {
1765        let mut excerpts = Vec::new();
1766        let snapshot = self.read(cx);
1767        let Some(path_key) = snapshot.path_keys.get(&buffer_id).cloned() else {
1768            return excerpts;
1769        };
1770
1771        let mut cursor = snapshot.excerpts.cursor::<PathKey>(());
1772        cursor.seek_forward(&path_key, Bias::Left);
1773
1774        while let Some(item) = cursor.item()
1775            && item.path_key == path_key
1776        {
1777            excerpts.push(item.range.clone());
1778            cursor.next()
1779        }
1780        excerpts
1781    }
1782
1783    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1784        let snapshot = self.read(cx);
1785        let mut excerpts = snapshot
1786            .excerpts
1787            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1788        let mut diff_transforms = snapshot
1789            .diff_transforms
1790            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1791        diff_transforms.next();
1792        let mut result = Vec::new();
1793        let Some(path_key) = snapshot.path_keys.get(&buffer_id) else {
1794            return result;
1795        };
1796
1797        while let Some(excerpt) = excerpts.item()
1798            && &excerpt.path_key == path_key
1799        {
1800            let excerpt_start = excerpts.start().1;
1801            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1802
1803            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1804            let overshoot = excerpt_start - diff_transforms.start().0;
1805            let start = diff_transforms.start().1 + overshoot;
1806
1807            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1808            let overshoot = excerpt_end - diff_transforms.start().0;
1809            let end = diff_transforms.start().1 + overshoot;
1810
1811            result.push(start.0..end.0);
1812            excerpts.next()
1813        }
1814        result
1815    }
1816
1817    // todo!() this seems bogus
1818    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1819        self.snapshot
1820            .borrow()
1821            .excerpts
1822            .iter()
1823            .map(|entry| entry.buffer.remote_id())
1824            .collect()
1825    }
1826
1827    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1828        let snapshot = self.read(cx);
1829        let offset = position.to_offset(&snapshot);
1830
1831        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1832        cursor.seek(&offset);
1833        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1834        Some(ExcerptInfo {
1835            path_key: excerpt.path_key.clone(),
1836            buffer_id: excerpt.buffer.remote_id(),
1837            range: excerpt.range.clone(),
1838        })
1839    }
1840
1841    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1842        let buffer_id = match anchor {
1843            Anchor::Min => self.snapshot(cx).excerpts.first()?.buffer.remote_id(),
1844            Anchor::Max => self.snapshot(cx).excerpts.last()?.buffer.remote_id(),
1845            Anchor::Text { buffer_id, .. } => buffer_id,
1846        };
1847        self.buffer(buffer_id)
1848    }
1849
1850    // If point is at the end of the buffer, the last excerpt is returned
1851    pub fn point_to_buffer_offset<T: ToOffset>(
1852        &self,
1853        point: T,
1854        cx: &App,
1855    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1856        let snapshot = self.read(cx);
1857        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1858        Some((
1859            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1860            offset,
1861        ))
1862    }
1863
1864    // If point is at the end of the buffer, the last excerpt is returned
1865    pub fn point_to_buffer_point<T: ToPoint>(
1866        &self,
1867        point: T,
1868        cx: &App,
1869    ) -> Option<(Entity<Buffer>, Point)> {
1870        let snapshot = self.read(cx);
1871        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1872        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1873    }
1874
1875    pub fn buffer_point_to_anchor(
1876        &self,
1877        // todo(lw): We shouldn't need this?
1878        buffer: &Entity<Buffer>,
1879        point: Point,
1880        cx: &App,
1881    ) -> Option<Anchor> {
1882        let mut found = None;
1883        let snapshot = buffer.read(cx).snapshot();
1884        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1885            let start = range.context.start.to_point(&snapshot);
1886            let end = range.context.end.to_point(&snapshot);
1887            if start <= point && point < end {
1888                found = Some(snapshot.clip_point(point, Bias::Left));
1889                break;
1890            }
1891            if point < start {
1892                found = Some(start);
1893            }
1894            if point > end {
1895                found = Some(end);
1896            }
1897        }
1898
1899        Some(Anchor::text(snapshot.anchor_after(found?)))
1900    }
1901
1902    pub fn buffer_anchor_to_anchor(
1903        &self,
1904        // todo(lw): We shouldn't need this?
1905        buffer: &Entity<Buffer>,
1906        anchor: text::Anchor,
1907        cx: &App,
1908    ) -> Option<Anchor> {
1909        let snapshot = buffer.read(cx).snapshot();
1910        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1911            if range.contains(&anchor, &snapshot) {
1912                return Some(Anchor::text(anchor));
1913            }
1914        }
1915
1916        None
1917    }
1918
1919    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1920        &self,
1921        anchors: Anchors,
1922        cx: &mut Context<Self>,
1923    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1924        let mut error = None;
1925        let mut futures = Vec::new();
1926        for anchor in anchors {
1927            if let Some(text_anchor) = anchor.text_anchor() {
1928                if let Some(buffer) = self.buffers.get(&text_anchor.buffer_id.unwrap()) {
1929                    buffer.buffer.update(cx, |buffer, _| {
1930                        futures.push(buffer.wait_for_anchors([text_anchor]))
1931                    });
1932                } else {
1933                    error = Some(anyhow!(
1934                        "buffer {:?} is not part of this multi-buffer",
1935                        text_anchor.buffer_id
1936                    ));
1937                    break;
1938                }
1939            }
1940        }
1941        async move {
1942            if let Some(error) = error {
1943                Err(error)?;
1944            }
1945            for future in futures {
1946                future.await?;
1947            }
1948            Ok(())
1949        }
1950    }
1951
1952    pub fn text_anchor_for_position<T: ToOffset>(
1953        &self,
1954        position: T,
1955        cx: &App,
1956    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1957        let snapshot = self.read(cx);
1958        let anchor = snapshot.anchor_before(position).text_anchor()?;
1959        let buffer = self.buffers.get(&anchor.buffer_id.unwrap())?.buffer.clone();
1960        Some((buffer, anchor))
1961    }
1962
1963    fn on_buffer_event(
1964        &mut self,
1965        buffer: Entity<Buffer>,
1966        event: &language::BufferEvent,
1967        cx: &mut Context<Self>,
1968    ) {
1969        use language::BufferEvent;
1970        let buffer_id = buffer.read(cx).remote_id();
1971        cx.emit(match event {
1972            BufferEvent::Edited => Event::Edited {
1973                edited_buffer: Some(buffer),
1974            },
1975            BufferEvent::DirtyChanged => Event::DirtyChanged,
1976            BufferEvent::Saved => Event::Saved,
1977            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1978            BufferEvent::Reloaded => Event::Reloaded,
1979            BufferEvent::LanguageChanged(has_language) => {
1980                Event::LanguageChanged(buffer_id, *has_language)
1981            }
1982            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1983            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1984            BufferEvent::CapabilityChanged => {
1985                self.capability = buffer.read(cx).capability();
1986                return;
1987            }
1988            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1989        });
1990    }
1991
1992    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1993        let diff = diff.read(cx);
1994        let buffer_id = diff.buffer_id;
1995        let diff = DiffStateSnapshot {
1996            diff: diff.snapshot(cx),
1997            main_buffer: None,
1998        };
1999        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2000    }
2001
2002    fn inverted_buffer_diff_language_changed(
2003        &mut self,
2004        diff: Entity<BufferDiff>,
2005        main_buffer: Entity<language::Buffer>,
2006        cx: &mut Context<Self>,
2007    ) {
2008        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2009        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2010        let diff = diff.read(cx);
2011        let diff = DiffStateSnapshot {
2012            diff: diff.snapshot(cx),
2013            main_buffer: Some(main_buffer_snapshot),
2014        };
2015        self.snapshot
2016            .get_mut()
2017            .diffs
2018            .insert(base_text_buffer_id, diff);
2019    }
2020
2021    fn buffer_diff_changed(
2022        &mut self,
2023        diff: Entity<BufferDiff>,
2024        range: Range<text::Anchor>,
2025        cx: &mut Context<Self>,
2026    ) {
2027        self.sync_mut(cx);
2028
2029        let diff = diff.read(cx);
2030        let buffer_id = diff.buffer_id;
2031
2032        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2033            return;
2034        };
2035        let new_diff = DiffStateSnapshot {
2036            diff: diff.snapshot(cx),
2037            main_buffer: None,
2038        };
2039        let mut snapshot = self.snapshot.get_mut();
2040        let base_text_changed = snapshot
2041            .diffs
2042            .get(&buffer_id)
2043            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2044        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2045
2046        let buffer = buffer_state.buffer.read(cx);
2047        let diff_change_range = range.to_offset(buffer);
2048
2049        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2050        let edits = Self::sync_diff_transforms(
2051            &mut snapshot,
2052            excerpt_edits,
2053            DiffChangeKind::DiffUpdated {
2054                base_changed: base_text_changed,
2055            },
2056        );
2057        if !edits.is_empty() {
2058            self.subscriptions.publish(edits);
2059        }
2060        cx.emit(Event::Edited {
2061            edited_buffer: None,
2062        });
2063    }
2064
2065    fn inverted_buffer_diff_changed(
2066        &mut self,
2067        diff: Entity<BufferDiff>,
2068        main_buffer: Entity<language::Buffer>,
2069        diff_change_range: Option<Range<usize>>,
2070        cx: &mut Context<Self>,
2071    ) {
2072        self.sync_mut(cx);
2073
2074        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2075        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2076            return;
2077        };
2078
2079        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2080        let diff = diff.read(cx);
2081        let new_diff = DiffStateSnapshot {
2082            diff: diff.snapshot(cx),
2083            main_buffer: Some(main_buffer_snapshot),
2084        };
2085        let mut snapshot = self.snapshot.get_mut();
2086        snapshot
2087            .diffs
2088            .insert_or_replace(base_text_buffer_id, new_diff);
2089
2090        let Some(diff_change_range) = diff_change_range else {
2091            return;
2092        };
2093
2094        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2095        let edits = Self::sync_diff_transforms(
2096            &mut snapshot,
2097            excerpt_edits,
2098            DiffChangeKind::DiffUpdated {
2099                // We don't read this field for inverted diffs.
2100                base_changed: false,
2101            },
2102        );
2103        if !edits.is_empty() {
2104            self.subscriptions.publish(edits);
2105        }
2106        cx.emit(Event::Edited {
2107            edited_buffer: None,
2108        });
2109    }
2110
2111    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2112        self.buffers.values().map(|state| state.buffer.clone())
2113    }
2114
2115    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2116        self.all_buffers_iter().collect()
2117    }
2118
2119    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2120        self.buffers.keys().copied()
2121    }
2122
2123    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2124        self.all_buffer_ids_iter().collect()
2125    }
2126
2127    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2128        self.buffers
2129            .get(&buffer_id)
2130            .map(|state| state.buffer.clone())
2131    }
2132
2133    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2134        self.point_to_buffer_offset(point, cx)
2135            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2136    }
2137
2138    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2139        let buffer_id = self
2140            .snapshot
2141            .borrow()
2142            .excerpts
2143            .first()
2144            .map(|excerpt| excerpt.buffer.remote_id());
2145        buffer_id
2146            .and_then(|buffer_id| self.buffer(buffer_id))
2147            .map(|buffer| {
2148                let buffer = buffer.read(cx);
2149                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2150            })
2151            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2152    }
2153
2154    pub fn language_settings_at<'a, T: ToOffset>(
2155        &'a self,
2156        point: T,
2157        cx: &'a App,
2158    ) -> Cow<'a, LanguageSettings> {
2159        let mut language = None;
2160        let mut file = None;
2161        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2162            let buffer = buffer.read(cx);
2163            language = buffer.language_at(offset);
2164            file = buffer.file();
2165        }
2166        language_settings(language.map(|l| l.name()), file, cx)
2167    }
2168
2169    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2170        self.buffers.values().for_each(|state| f(&state.buffer))
2171    }
2172
2173    pub fn explicit_title(&self) -> Option<&str> {
2174        self.title.as_deref()
2175    }
2176
2177    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2178        if let Some(title) = self.title.as_ref() {
2179            return title.into();
2180        }
2181
2182        if let Some(buffer) = self.as_singleton() {
2183            let buffer = buffer.read(cx);
2184
2185            if let Some(file) = buffer.file() {
2186                return file.file_name(cx).into();
2187            }
2188
2189            if let Some(title) = self.buffer_content_title(buffer) {
2190                return title;
2191            }
2192        };
2193
2194        "untitled".into()
2195    }
2196
2197    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2198        let mut is_leading_whitespace = true;
2199        let mut count = 0;
2200        let mut prev_was_space = false;
2201        let mut title = String::new();
2202
2203        for ch in buffer.snapshot().chars() {
2204            if is_leading_whitespace && ch.is_whitespace() {
2205                continue;
2206            }
2207
2208            is_leading_whitespace = false;
2209
2210            if ch == '\n' || count >= 40 {
2211                break;
2212            }
2213
2214            if ch.is_whitespace() {
2215                if !prev_was_space {
2216                    title.push(' ');
2217                    count += 1;
2218                    prev_was_space = true;
2219                }
2220            } else {
2221                title.push(ch);
2222                count += 1;
2223                prev_was_space = false;
2224            }
2225        }
2226
2227        let title = title.trim_end().to_string();
2228
2229        if title.is_empty() {
2230            return None;
2231        }
2232
2233        Some(title.into())
2234    }
2235
2236    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2237        self.title = Some(title);
2238        cx.notify();
2239    }
2240
2241    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2242    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2243        for buffer_state in self.buffers.values() {
2244            buffer_state
2245                .buffer
2246                .update(cx, |buffer, _cx| buffer.refresh_preview());
2247        }
2248    }
2249
2250    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2251    pub fn preserve_preview(&self, cx: &App) -> bool {
2252        self.buffers
2253            .values()
2254            .all(|state| state.buffer.read(cx).preserve_preview())
2255    }
2256
2257    #[cfg(any(test, feature = "test-support"))]
2258    pub fn is_parsing(&self, cx: &App) -> bool {
2259        self.as_singleton().unwrap().read(cx).is_parsing()
2260    }
2261
2262    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2263        let buffer_id = diff.read(cx).buffer_id;
2264
2265        if let Some(existing_diff) = self.diff_for(buffer_id)
2266            && diff.entity_id() == existing_diff.entity_id()
2267        {
2268            return;
2269        }
2270
2271        self.buffer_diff_changed(
2272            diff.clone(),
2273            text::Anchor::min_max_range_for_buffer(buffer_id),
2274            cx,
2275        );
2276        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2277    }
2278
2279    pub fn add_inverted_diff(
2280        &mut self,
2281        diff: Entity<BufferDiff>,
2282        main_buffer: Entity<language::Buffer>,
2283        cx: &mut Context<Self>,
2284    ) {
2285        let snapshot = diff.read(cx).base_text(cx);
2286        let base_text_buffer_id = snapshot.remote_id();
2287        let diff_change_range = 0..snapshot.len();
2288        self.snapshot.get_mut().has_inverted_diff = true;
2289        self.inverted_buffer_diff_changed(
2290            diff.clone(),
2291            main_buffer.clone(),
2292            Some(diff_change_range),
2293            cx,
2294        );
2295        self.diffs.insert(
2296            base_text_buffer_id,
2297            DiffState::new_inverted(diff, main_buffer, cx),
2298        );
2299    }
2300
2301    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2302        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2303    }
2304
2305    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2306        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2307    }
2308
2309    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2310        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2311    }
2312
2313    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2314        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2315        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2316    }
2317
2318    pub fn all_diff_hunks_expanded(&self) -> bool {
2319        self.snapshot.borrow().all_diff_hunks_expanded
2320    }
2321
2322    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2323        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2324        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2325    }
2326
2327    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2328        self.snapshot.get_mut().show_deleted_hunks = show;
2329
2330        self.sync_mut(cx);
2331
2332        let old_len = self.snapshot.borrow().len();
2333
2334        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2335        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2336
2337        let new_len = self.snapshot.borrow().len();
2338
2339        self.subscriptions.publish(vec![Edit {
2340            old: MultiBufferOffset(0)..old_len,
2341            new: MultiBufferOffset(0)..new_len,
2342        }]);
2343
2344        cx.emit(Event::DiffHunksToggled);
2345        cx.emit(Event::Edited {
2346            edited_buffer: None,
2347        });
2348    }
2349
2350    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2351        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2352    }
2353
2354    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2355        self.read(cx)
2356            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2357            .nth(1)
2358            .is_some()
2359    }
2360
2361    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2362        let snapshot = self.read(cx);
2363        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2364        let offset_range = range.to_offset(&snapshot);
2365        cursor.seek(&offset_range.start, Bias::Left);
2366        while let Some(item) = cursor.item() {
2367            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2368                break;
2369            }
2370            if item.hunk_info().is_some() {
2371                return true;
2372            }
2373            cursor.next();
2374        }
2375        false
2376    }
2377
2378    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2379        let snapshot = self.read(cx);
2380        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2381        for range in ranges {
2382            let range = range.to_point(&snapshot);
2383            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2384            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2385                .min(snapshot.len());
2386            cursor.seek(&start, Bias::Right);
2387            while let Some(item) = cursor.item() {
2388                if *cursor.start() >= end {
2389                    break;
2390                }
2391                if item.hunk_info().is_some() {
2392                    return true;
2393                }
2394                cursor.next();
2395            }
2396        }
2397        false
2398    }
2399
2400    pub fn expand_or_collapse_diff_hunks_inner(
2401        &mut self,
2402        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2403        expand: bool,
2404        cx: &mut Context<Self>,
2405    ) -> Vec<Edit<MultiBufferOffset>> {
2406        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2407            return Vec::new();
2408        }
2409        self.sync_mut(cx);
2410        let mut snapshot = self.snapshot.get_mut();
2411        let mut excerpt_edits = Vec::new();
2412        let mut last_hunk_row = None;
2413        for (range, end_excerpt_id) in ranges {
2414            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2415                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2416                    continue;
2417                }
2418                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2419                    continue;
2420                }
2421                let start = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2422                let end = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2423                let start = snapshot.excerpt_offset_for_anchor(&start);
2424                let end = snapshot.excerpt_offset_for_anchor(&end);
2425                last_hunk_row = Some(diff_hunk.row_range.start);
2426                excerpt_edits.push(text::Edit {
2427                    old: start..end,
2428                    new: start..end,
2429                });
2430            }
2431        }
2432
2433        Self::sync_diff_transforms(
2434            &mut snapshot,
2435            excerpt_edits,
2436            DiffChangeKind::ExpandOrCollapseHunks { expand },
2437        )
2438    }
2439
2440    pub fn expand_or_collapse_diff_hunks(
2441        &mut self,
2442        ranges: Vec<Range<Anchor>>,
2443        expand: bool,
2444        cx: &mut Context<Self>,
2445    ) {
2446        let snapshot = self.snapshot.borrow().clone();
2447        let ranges = ranges.iter().map(move |range| {
2448            let end_excerpt_id = range.end.excerpt_id;
2449            let range = range.to_point(&snapshot);
2450            let mut peek_end = range.end;
2451            if range.end.row < snapshot.max_row().0 {
2452                peek_end = Point::new(range.end.row + 1, 0);
2453            };
2454            (range.start..peek_end, end_excerpt_id)
2455        });
2456        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2457        if !edits.is_empty() {
2458            self.subscriptions.publish(edits);
2459        }
2460        cx.emit(Event::DiffHunksToggled);
2461        cx.emit(Event::Edited {
2462            edited_buffer: None,
2463        });
2464    }
2465
2466    pub fn resize_excerpt(
2467        &mut self,
2468        id: ExcerptId,
2469        range: Range<text::Anchor>,
2470        cx: &mut Context<Self>,
2471    ) {
2472        self.sync_mut(cx);
2473
2474        let mut snapshot = self.snapshot.get_mut();
2475        let locator = snapshot.excerpt_locator_for_id(id);
2476        let mut new_excerpts = SumTree::default();
2477        let mut cursor = snapshot
2478            .excerpts
2479            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2480        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2481
2482        let prefix = cursor.slice(&Some(locator), Bias::Left);
2483        new_excerpts.append(prefix, ());
2484
2485        let mut excerpt = cursor.item().unwrap().clone();
2486        let old_text_len = excerpt.text_summary.len;
2487
2488        excerpt.range.context.start = range.start;
2489        excerpt.range.context.end = range.end;
2490        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2491
2492        excerpt.text_summary = excerpt
2493            .buffer
2494            .text_summary_for_range(excerpt.range.context.clone());
2495
2496        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2497        let old_start_offset = cursor.start().1;
2498        let new_text_len = excerpt.text_summary.len;
2499        let edit = Edit {
2500            old: old_start_offset..old_start_offset + old_text_len,
2501            new: new_start_offset..new_start_offset + new_text_len,
2502        };
2503
2504        if let Some(last_edit) = edits.last_mut() {
2505            if last_edit.old.end == edit.old.start {
2506                last_edit.old.end = edit.old.end;
2507                last_edit.new.end = edit.new.end;
2508            } else {
2509                edits.push(edit);
2510            }
2511        } else {
2512            edits.push(edit);
2513        }
2514
2515        new_excerpts.push(excerpt, ());
2516
2517        cursor.next();
2518
2519        new_excerpts.append(cursor.suffix(), ());
2520
2521        drop(cursor);
2522        snapshot.excerpts = new_excerpts;
2523
2524        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2525        if !edits.is_empty() {
2526            self.subscriptions.publish(edits);
2527        }
2528        cx.emit(Event::Edited {
2529            edited_buffer: None,
2530        });
2531        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2532        cx.notify();
2533    }
2534
2535    pub fn expand_excerpts(
2536        &mut self,
2537        ids: impl IntoIterator<Item = ExcerptId>,
2538        line_count: u32,
2539        direction: ExpandExcerptDirection,
2540        cx: &mut Context<Self>,
2541    ) {
2542        if line_count == 0 {
2543            return;
2544        }
2545        self.sync_mut(cx);
2546        if !self.excerpts_by_path.is_empty() {
2547            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2548            return;
2549        }
2550        let mut snapshot = self.snapshot.get_mut();
2551
2552        let ids = ids.into_iter().collect::<Vec<_>>();
2553        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2554        let mut new_excerpts = SumTree::default();
2555        let mut cursor = snapshot
2556            .excerpts
2557            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2558        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2559
2560        for locator in &locators {
2561            let prefix = cursor.slice(&Some(locator), Bias::Left);
2562            new_excerpts.append(prefix, ());
2563
2564            let mut excerpt = cursor.item().unwrap().clone();
2565            let old_text_len = excerpt.text_summary.len;
2566
2567            let up_line_count = if direction.should_expand_up() {
2568                line_count
2569            } else {
2570                0
2571            };
2572
2573            let start_row = excerpt
2574                .range
2575                .context
2576                .start
2577                .to_point(&excerpt.buffer)
2578                .row
2579                .saturating_sub(up_line_count);
2580            let start_point = Point::new(start_row, 0);
2581            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2582
2583            let down_line_count = if direction.should_expand_down() {
2584                line_count
2585            } else {
2586                0
2587            };
2588
2589            let mut end_point = excerpt.buffer.clip_point(
2590                excerpt.range.context.end.to_point(&excerpt.buffer)
2591                    + Point::new(down_line_count, 0),
2592                Bias::Left,
2593            );
2594            end_point.column = excerpt.buffer.line_len(end_point.row);
2595            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2596            excerpt.max_buffer_row = end_point.row;
2597
2598            excerpt.text_summary = excerpt
2599                .buffer
2600                .text_summary_for_range(excerpt.range.context.clone());
2601
2602            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2603            let old_start_offset = cursor.start().1;
2604            let new_text_len = excerpt.text_summary.len;
2605            let edit = Edit {
2606                old: old_start_offset..old_start_offset + old_text_len,
2607                new: new_start_offset..new_start_offset + new_text_len,
2608            };
2609
2610            if let Some(last_edit) = edits.last_mut() {
2611                if last_edit.old.end == edit.old.start {
2612                    last_edit.old.end = edit.old.end;
2613                    last_edit.new.end = edit.new.end;
2614                } else {
2615                    edits.push(edit);
2616                }
2617            } else {
2618                edits.push(edit);
2619            }
2620
2621            new_excerpts.push(excerpt, ());
2622
2623            cursor.next();
2624        }
2625
2626        new_excerpts.append(cursor.suffix(), ());
2627
2628        drop(cursor);
2629        snapshot.excerpts = new_excerpts;
2630
2631        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2632        if !edits.is_empty() {
2633            self.subscriptions.publish(edits);
2634        }
2635        cx.emit(Event::Edited {
2636            edited_buffer: None,
2637        });
2638        cx.emit(Event::ExcerptsExpanded { ids });
2639        cx.notify();
2640    }
2641
2642    #[ztracing::instrument(skip_all)]
2643    fn sync(&self, cx: &App) {
2644        let changed = self.buffer_changed_since_sync.replace(false);
2645        if !changed {
2646            return;
2647        }
2648        let edits = Self::sync_from_buffer_changes(
2649            &mut self.snapshot.borrow_mut(),
2650            &self.buffers,
2651            &self.diffs,
2652            cx,
2653        );
2654        if !edits.is_empty() {
2655            self.subscriptions.publish(edits);
2656        }
2657    }
2658
2659    fn sync_mut(&mut self, cx: &App) {
2660        let changed = self.buffer_changed_since_sync.replace(false);
2661        if !changed {
2662            return;
2663        }
2664        let edits =
2665            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2666
2667        if !edits.is_empty() {
2668            self.subscriptions.publish(edits);
2669        }
2670    }
2671
2672    fn sync_from_buffer_changes(
2673        snapshot: &mut MultiBufferSnapshot,
2674        buffers: &BTreeMap<BufferId, BufferState>,
2675        diffs: &HashMap<BufferId, DiffState>,
2676        cx: &App,
2677    ) -> Vec<Edit<MultiBufferOffset>> {
2678        let MultiBufferSnapshot {
2679            excerpts,
2680            buffer_paths: _,
2681            diffs: buffer_diff,
2682            diff_transforms: _,
2683            non_text_state_update_count,
2684            edit_count,
2685            is_dirty,
2686            has_deleted_file,
2687            has_conflict,
2688            has_inverted_diff: _,
2689            singleton: _,
2690            trailing_excerpt_update_count: _,
2691            all_diff_hunks_expanded: _,
2692            show_deleted_hunks: _,
2693            use_extended_diff_range: _,
2694            show_headers: _,
2695        } = snapshot;
2696        *is_dirty = false;
2697        *has_deleted_file = false;
2698        *has_conflict = false;
2699
2700        if !diffs.is_empty() {
2701            let mut diffs_to_add = Vec::new();
2702            for (id, diff) in diffs {
2703                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2704                // and use the diff hunk base text ranges to compute diff transforms.
2705                // Those base text ranges are usize, so make sure if the base text changed
2706                // we also update the diff snapshot so that we don't use stale offsets
2707                if buffer_diff.get(id).is_none_or(|existing_diff| {
2708                    if existing_diff.main_buffer.is_none() {
2709                        return false;
2710                    }
2711                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2712                    base_text.remote_id() != existing_diff.base_text().remote_id()
2713                        || base_text
2714                            .version()
2715                            .changed_since(existing_diff.base_text().version())
2716                }) {
2717                    if diffs_to_add.capacity() == 0 {
2718                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2719                        // meaning re-allocations will be fairly expensive
2720                        diffs_to_add.reserve(diffs.len());
2721                    }
2722                    diffs_to_add.push((*id, diff.snapshot(cx)));
2723                }
2724            }
2725            buffer_diff.extend(diffs_to_add);
2726        }
2727
2728        let mut excerpts_to_edit = Vec::new();
2729        let mut non_text_state_updated = false;
2730        let mut edited = false;
2731        for buffer_state in buffers.values() {
2732            let buffer = buffer_state.buffer.read(cx);
2733            let version = buffer.version();
2734            let non_text_state_update_count = buffer.non_text_state_update_count();
2735
2736            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2737            let buffer_non_text_state_updated =
2738                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2739            if buffer_edited || buffer_non_text_state_updated {
2740                *buffer_state.last_version.borrow_mut() = version;
2741                buffer_state
2742                    .last_non_text_state_update_count
2743                    .set(non_text_state_update_count);
2744                excerpts_to_edit.extend(
2745                    buffer_state
2746                        .excerpts
2747                        .iter()
2748                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2749                );
2750            }
2751
2752            edited |= buffer_edited;
2753            non_text_state_updated |= buffer_non_text_state_updated;
2754            *is_dirty |= buffer.is_dirty();
2755            *has_deleted_file |= buffer
2756                .file()
2757                .is_some_and(|file| file.disk_state().is_deleted());
2758            *has_conflict |= buffer.has_conflict();
2759        }
2760        if edited {
2761            *edit_count += 1;
2762        }
2763        if non_text_state_updated {
2764            *non_text_state_update_count += 1;
2765        }
2766
2767        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
2768
2769        let mut edits = Vec::new();
2770        let mut new_excerpts = SumTree::default();
2771        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2772
2773        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2774            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2775            let old_excerpt = cursor.item().unwrap();
2776            let buffer = buffer.read(cx);
2777            let buffer_id = buffer.remote_id();
2778            let mut new_excerpt;
2779            if buffer_edited {
2780                edits.extend(
2781                    buffer
2782                        .edits_since_in_range::<usize>(
2783                            old_excerpt.buffer.version(),
2784                            old_excerpt.range.context.clone(),
2785                        )
2786                        .map(|edit| {
2787                            let excerpt_old_start = cursor.start().1;
2788                            let excerpt_new_start =
2789                                ExcerptDimension(new_excerpts.summary().text.len);
2790                            let old_start = excerpt_old_start + edit.old.start;
2791                            let old_end = excerpt_old_start + edit.old.end;
2792                            let new_start = excerpt_new_start + edit.new.start;
2793                            let new_end = excerpt_new_start + edit.new.end;
2794                            Edit {
2795                                old: old_start..old_end,
2796                                new: new_start..new_end,
2797                            }
2798                        }),
2799                );
2800
2801                new_excerpt = Excerpt::new(
2802                    old_excerpt.id,
2803                    locator.clone(),
2804                    buffer_id,
2805                    Arc::new(buffer.snapshot()),
2806                    old_excerpt.range.clone(),
2807                    old_excerpt.has_trailing_newline,
2808                );
2809            } else {
2810                new_excerpt = old_excerpt.clone();
2811                new_excerpt.buffer = Arc::new(buffer.snapshot());
2812            }
2813
2814            new_excerpts.push(new_excerpt, ());
2815            cursor.next();
2816        }
2817        new_excerpts.append(cursor.suffix(), ());
2818
2819        drop(cursor);
2820        *excerpts = new_excerpts;
2821
2822        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2823    }
2824
2825    fn sync_diff_transforms(
2826        snapshot: &mut MultiBufferSnapshot,
2827        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2828        change_kind: DiffChangeKind,
2829    ) -> Vec<Edit<MultiBufferOffset>> {
2830        if excerpt_edits.is_empty() {
2831            return vec![];
2832        }
2833
2834        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2835        let mut old_diff_transforms = snapshot
2836            .diff_transforms
2837            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2838        let mut new_diff_transforms = SumTree::default();
2839        let mut old_expanded_hunks = HashSet::default();
2840        let mut output_edits = Vec::new();
2841        let mut output_delta = 0_isize;
2842        let mut at_transform_boundary = true;
2843        let mut end_of_current_insert = None;
2844
2845        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2846        while let Some(edit) = excerpt_edits.next() {
2847            excerpts.seek_forward(&edit.new.start, Bias::Right);
2848            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2849                excerpts.prev();
2850            }
2851
2852            // Keep any transforms that are before the edit.
2853            if at_transform_boundary {
2854                at_transform_boundary = false;
2855                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2856                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2857                if let Some(transform) = old_diff_transforms.item()
2858                    && old_diff_transforms.end().0 == edit.old.start
2859                    && old_diff_transforms.start().0 < edit.old.start
2860                {
2861                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2862                    old_diff_transforms.next();
2863                }
2864            }
2865
2866            // Compute the start of the edit in output coordinates.
2867            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2868            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2869            let edit_new_start =
2870                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2871
2872            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2873                &edit,
2874                &mut excerpts,
2875                &mut old_diff_transforms,
2876                &mut new_diff_transforms,
2877                &mut end_of_current_insert,
2878                &mut old_expanded_hunks,
2879                snapshot,
2880                change_kind,
2881            );
2882
2883            // Compute the end of the edit in output coordinates.
2884            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2885            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2886            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2887            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2888            let output_edit = Edit {
2889                old: edit_old_start..edit_old_end,
2890                new: edit_new_start..edit_new_end,
2891            };
2892
2893            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2894            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2895            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2896                output_edits.push(output_edit);
2897            }
2898
2899            // If this is the last edit that intersects the current diff transform,
2900            // then recreate the content up to the end of this transform, to prepare
2901            // for reusing additional slices of the old transforms.
2902            if excerpt_edits
2903                .peek()
2904                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2905            {
2906                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2907                    && match old_diff_transforms.item() {
2908                        Some(DiffTransform::BufferContent {
2909                            inserted_hunk_info: Some(hunk),
2910                            ..
2911                        }) => excerpts.item().is_some_and(|excerpt| {
2912                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2913                                && diff.main_buffer.is_some()
2914                            {
2915                                return true;
2916                            }
2917                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2918                        }),
2919                        _ => true,
2920                    };
2921
2922                let mut excerpt_offset = edit.new.end;
2923                if !keep_next_old_transform {
2924                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2925                    old_diff_transforms.next();
2926                }
2927
2928                old_expanded_hunks.clear();
2929                Self::push_buffer_content_transform(
2930                    snapshot,
2931                    &mut new_diff_transforms,
2932                    excerpt_offset,
2933                    end_of_current_insert,
2934                );
2935                at_transform_boundary = true;
2936            }
2937        }
2938
2939        // Keep any transforms that are after the last edit.
2940        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2941
2942        // Ensure there's always at least one buffer content transform.
2943        if new_diff_transforms.is_empty() {
2944            new_diff_transforms.push(
2945                DiffTransform::BufferContent {
2946                    summary: Default::default(),
2947                    inserted_hunk_info: None,
2948                },
2949                (),
2950            );
2951        }
2952
2953        drop(old_diff_transforms);
2954        drop(excerpts);
2955        snapshot.diff_transforms = new_diff_transforms;
2956        snapshot.edit_count += 1;
2957
2958        #[cfg(any(test, feature = "test-support"))]
2959        snapshot.check_invariants();
2960        output_edits
2961    }
2962
2963    fn recompute_diff_transforms_for_edit(
2964        edit: &Edit<ExcerptOffset>,
2965        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2966        old_diff_transforms: &mut Cursor<
2967            DiffTransform,
2968            Dimensions<ExcerptOffset, MultiBufferOffset>,
2969        >,
2970        new_diff_transforms: &mut SumTree<DiffTransform>,
2971        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2972        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2973        snapshot: &MultiBufferSnapshot,
2974        change_kind: DiffChangeKind,
2975    ) -> bool {
2976        log::trace!(
2977            "recomputing diff transform for edit {:?} => {:?}",
2978            edit.old.start..edit.old.end,
2979            edit.new.start..edit.new.end
2980        );
2981
2982        // Record which hunks were previously expanded.
2983        while let Some(item) = old_diff_transforms.item() {
2984            if let Some(hunk_info) = item.hunk_info() {
2985                log::trace!(
2986                    "previously expanded hunk at {:?}",
2987                    old_diff_transforms.start()
2988                );
2989                old_expanded_hunks.insert(hunk_info);
2990            }
2991            if old_diff_transforms.end().0 > edit.old.end {
2992                break;
2993            }
2994            old_diff_transforms.next();
2995        }
2996
2997        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2998        // For inverted diffs, hunks are always shown, so we can't skip this.
2999        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3000        if old_expanded_hunks.is_empty()
3001            && change_kind == DiffChangeKind::BufferEdited
3002            && !all_diff_hunks_expanded
3003            && !snapshot.has_inverted_diff
3004        {
3005            return false;
3006        }
3007
3008        // Visit each excerpt that intersects the edit.
3009        let mut did_expand_hunks = false;
3010        while let Some(excerpt) = excerpts.item() {
3011            // Recompute the expanded hunks in the portion of the excerpt that
3012            // intersects the edit.
3013            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3014                let buffer = &excerpt.buffer;
3015                let excerpt_start = *excerpts.start();
3016                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3017                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3018                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3019                let edit_buffer_start =
3020                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3021                let edit_buffer_end =
3022                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3023                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3024
3025                if let Some(main_buffer) = &diff.main_buffer {
3026                    for hunk in diff.hunks_intersecting_base_text_range(
3027                        edit_buffer_start..edit_buffer_end,
3028                        main_buffer,
3029                    ) {
3030                        did_expand_hunks = true;
3031                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3032                        if hunk_buffer_range.start < excerpt_buffer_start {
3033                            log::trace!("skipping hunk that starts before excerpt");
3034                            continue;
3035                        }
3036                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3037                        let hunk_excerpt_start = excerpt_start
3038                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3039                        let hunk_excerpt_end = excerpt_end
3040                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3041                        Self::push_buffer_content_transform(
3042                            snapshot,
3043                            new_diff_transforms,
3044                            hunk_excerpt_start,
3045                            *end_of_current_insert,
3046                        );
3047                        if !hunk_buffer_range.is_empty() {
3048                            let hunk_info = DiffTransformHunkInfo {
3049                                excerpt_id: excerpt.id,
3050                                hunk_start_anchor: hunk.buffer_range.start,
3051                                hunk_secondary_status: hunk.secondary_status,
3052                                is_logically_deleted: true,
3053                            };
3054                            *end_of_current_insert =
3055                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3056                        }
3057                    }
3058                } else {
3059                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3060                        ..buffer.anchor_after(edit_buffer_end);
3061                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3062                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3063                            continue;
3064                        }
3065
3066                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3067                        if hunk_buffer_range.start < excerpt_buffer_start {
3068                            log::trace!("skipping hunk that starts before excerpt");
3069                            continue;
3070                        }
3071
3072                        let hunk_info = DiffTransformHunkInfo {
3073                            excerpt_id: excerpt.id,
3074                            hunk_start_anchor: hunk.buffer_range.start,
3075                            hunk_secondary_status: hunk.secondary_status,
3076                            is_logically_deleted: false,
3077                        };
3078
3079                        let hunk_excerpt_start = excerpt_start
3080                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3081                        let hunk_excerpt_end = excerpt_end
3082                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3083
3084                        Self::push_buffer_content_transform(
3085                            snapshot,
3086                            new_diff_transforms,
3087                            hunk_excerpt_start,
3088                            *end_of_current_insert,
3089                        );
3090
3091                        // For every existing hunk, determine if it was previously expanded
3092                        // and if it should currently be expanded.
3093                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3094                        let should_expand_hunk = match &change_kind {
3095                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3096                                was_previously_expanded || all_diff_hunks_expanded
3097                            }
3098                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3099                                let intersects = hunk_buffer_range.is_empty()
3100                                    || hunk_buffer_range.end > edit_buffer_start;
3101                                if *expand {
3102                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3103                                } else {
3104                                    !intersects
3105                                        && (was_previously_expanded || all_diff_hunks_expanded)
3106                                }
3107                            }
3108                            _ => was_previously_expanded || all_diff_hunks_expanded,
3109                        };
3110
3111                        if should_expand_hunk {
3112                            did_expand_hunks = true;
3113                            log::trace!(
3114                                "expanding hunk {:?}, excerpt:{:?}",
3115                                hunk_excerpt_start..hunk_excerpt_end,
3116                                excerpt.id
3117                            );
3118
3119                            if !hunk.diff_base_byte_range.is_empty()
3120                                && hunk_buffer_range.start >= edit_buffer_start
3121                                && hunk_buffer_range.start <= excerpt_buffer_end
3122                                && snapshot.show_deleted_hunks
3123                            {
3124                                let base_text = diff.base_text();
3125                                let mut text_cursor =
3126                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3127                                let mut base_text_summary = text_cursor
3128                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3129
3130                                let mut has_trailing_newline = false;
3131                                if base_text_summary.last_line_chars > 0 {
3132                                    base_text_summary += TextSummary::newline();
3133                                    has_trailing_newline = true;
3134                                }
3135
3136                                new_diff_transforms.push(
3137                                    DiffTransform::DeletedHunk {
3138                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3139                                        summary: base_text_summary,
3140                                        buffer_id: excerpt.buffer_id,
3141                                        hunk_info,
3142                                        has_trailing_newline,
3143                                    },
3144                                    (),
3145                                );
3146                            }
3147
3148                            if !hunk_buffer_range.is_empty() {
3149                                *end_of_current_insert =
3150                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3151                            }
3152                        }
3153                    }
3154                }
3155            }
3156
3157            if excerpts.end() <= edit.new.end {
3158                excerpts.next();
3159            } else {
3160                break;
3161            }
3162        }
3163
3164        did_expand_hunks || !old_expanded_hunks.is_empty()
3165    }
3166
3167    fn append_diff_transforms(
3168        new_transforms: &mut SumTree<DiffTransform>,
3169        subtree: SumTree<DiffTransform>,
3170    ) {
3171        if let Some(DiffTransform::BufferContent {
3172            inserted_hunk_info,
3173            summary,
3174        }) = subtree.first()
3175            && Self::extend_last_buffer_content_transform(
3176                new_transforms,
3177                *inserted_hunk_info,
3178                *summary,
3179            )
3180        {
3181            let mut cursor = subtree.cursor::<()>(());
3182            cursor.next();
3183            cursor.next();
3184            new_transforms.append(cursor.suffix(), ());
3185            return;
3186        }
3187        new_transforms.append(subtree, ());
3188    }
3189
3190    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3191        if let DiffTransform::BufferContent {
3192            inserted_hunk_info: inserted_hunk_anchor,
3193            summary,
3194        } = transform
3195            && Self::extend_last_buffer_content_transform(
3196                new_transforms,
3197                inserted_hunk_anchor,
3198                summary,
3199            )
3200        {
3201            return;
3202        }
3203        new_transforms.push(transform, ());
3204    }
3205
3206    fn push_buffer_content_transform(
3207        old_snapshot: &MultiBufferSnapshot,
3208        new_transforms: &mut SumTree<DiffTransform>,
3209        end_offset: ExcerptOffset,
3210        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3211    ) {
3212        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3213            (end_offset.min(insertion_end_offset), Some(hunk_info))
3214        });
3215        let unchanged_region = [(end_offset, None)];
3216
3217        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3218        {
3219            let start_offset = new_transforms.summary().excerpt_len();
3220            if end_offset <= start_offset {
3221                continue;
3222            }
3223            let summary_to_add = old_snapshot
3224                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3225
3226            if !Self::extend_last_buffer_content_transform(
3227                new_transforms,
3228                inserted_hunk_info,
3229                summary_to_add,
3230            ) {
3231                new_transforms.push(
3232                    DiffTransform::BufferContent {
3233                        summary: summary_to_add,
3234                        inserted_hunk_info,
3235                    },
3236                    (),
3237                )
3238            }
3239        }
3240    }
3241
3242    fn extend_last_buffer_content_transform(
3243        new_transforms: &mut SumTree<DiffTransform>,
3244        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3245        summary_to_add: MBTextSummary,
3246    ) -> bool {
3247        let mut did_extend = false;
3248        new_transforms.update_last(
3249            |last_transform| {
3250                if let DiffTransform::BufferContent {
3251                    summary,
3252                    inserted_hunk_info: inserted_hunk_anchor,
3253                } = last_transform
3254                    && *inserted_hunk_anchor == new_inserted_hunk_info
3255                {
3256                    *summary += summary_to_add;
3257                    did_extend = true;
3258                }
3259            },
3260            (),
3261        );
3262        did_extend
3263    }
3264
3265    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3266        let snapshot = self.snapshot(cx);
3267        let excerpt_id = range.end.excerpt_id;
3268        let point_range = range.to_point(&snapshot);
3269        let expand = !self.single_hunk_is_expanded(range, cx);
3270        let edits =
3271            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3272        if !edits.is_empty() {
3273            self.subscriptions.publish(edits);
3274        }
3275        cx.emit(Event::DiffHunksToggled);
3276        cx.emit(Event::Edited {
3277            edited_buffer: None,
3278        });
3279    }
3280}
3281
3282fn build_excerpt_ranges(
3283    ranges: impl IntoIterator<Item = Range<Point>>,
3284    context_line_count: u32,
3285    buffer_snapshot: &BufferSnapshot,
3286) -> Vec<ExcerptRange<Point>> {
3287    ranges
3288        .into_iter()
3289        .map(|range| {
3290            let start_row = range.start.row.saturating_sub(context_line_count);
3291            let start = Point::new(start_row, 0);
3292            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3293            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3294            ExcerptRange {
3295                context: start..end,
3296                primary: range,
3297            }
3298        })
3299        .collect()
3300}
3301
3302#[cfg(any(test, feature = "test-support"))]
3303impl MultiBuffer {
3304    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3305        let buffer = cx.new(|cx| Buffer::local(text, cx));
3306        cx.new(|cx| Self::singleton(buffer, cx))
3307    }
3308
3309    pub fn build_multi<const COUNT: usize>(
3310        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3311        cx: &mut gpui::App,
3312    ) -> Entity<Self> {
3313        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3314        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3315            let buffer = cx.new(|cx| Buffer::local(text, cx));
3316            let snapshot = buffer.read(cx).snapshot();
3317            let excerpt_ranges = ranges
3318                .into_iter()
3319                .map(ExcerptRange::new)
3320                .collect::<Vec<_>>();
3321            multi.update(cx, |multi, cx| {
3322                multi.set_excerpt_ranges_for_path(
3323                    PathKey::sorted(ix as u64),
3324                    buffer,
3325                    &snapshot,
3326                    excerpt_ranges,
3327                    cx,
3328                )
3329            });
3330        }
3331
3332        multi
3333    }
3334
3335    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3336        cx.new(|cx| Self::singleton(buffer, cx))
3337    }
3338
3339    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3340        cx.new(|cx| {
3341            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3342            let mutation_count = rng.random_range(1..=5);
3343            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3344            multibuffer
3345        })
3346    }
3347
3348    pub fn randomly_edit(
3349        &mut self,
3350        rng: &mut impl rand::Rng,
3351        edit_count: usize,
3352        cx: &mut Context<Self>,
3353    ) {
3354        use util::RandomCharIter;
3355
3356        let snapshot = self.read(cx);
3357        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3358        let mut last_end = None;
3359        for _ in 0..edit_count {
3360            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3361                break;
3362            }
3363
3364            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3365            let end =
3366                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3367            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3368            last_end = Some(end);
3369
3370            let mut range = start..end;
3371            if rng.random_bool(0.2) {
3372                mem::swap(&mut range.start, &mut range.end);
3373            }
3374
3375            let new_text_len = rng.random_range(0..10);
3376            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3377
3378            edits.push((range, new_text.into()));
3379        }
3380        log::info!("mutating multi-buffer with {:?}", edits);
3381        drop(snapshot);
3382
3383        self.edit(edits, None, cx);
3384    }
3385
3386    pub fn randomly_edit_excerpts(
3387        &mut self,
3388        rng: &mut impl rand::Rng,
3389        mutation_count: usize,
3390        cx: &mut Context<Self>,
3391    ) {
3392        use rand::prelude::*;
3393        use std::env;
3394        use util::RandomCharIter;
3395
3396        let max_excerpts = env::var("MAX_EXCERPTS")
3397            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3398            .unwrap_or(5);
3399
3400        let mut buffers = Vec::new();
3401        for _ in 0..mutation_count {
3402            if rng.random_bool(0.05) {
3403                log::info!("Clearing multi-buffer");
3404                self.clear(cx);
3405                continue;
3406            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3407                let ids = self.excerpt_ids();
3408                let mut excerpts = HashSet::default();
3409                for _ in 0..rng.random_range(0..ids.len()) {
3410                    excerpts.extend(ids.choose(rng).copied());
3411                }
3412
3413                let line_count = rng.random_range(0..5);
3414
3415                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3416
3417                self.expand_excerpts(
3418                    excerpts.iter().cloned(),
3419                    line_count,
3420                    ExpandExcerptDirection::UpAndDown,
3421                    cx,
3422                );
3423                continue;
3424            }
3425
3426            let excerpt_ids = self.excerpt_ids();
3427            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3428                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3429                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3430                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3431                    let buffer = buffers.last().unwrap().read(cx);
3432                    log::info!(
3433                        "Creating new buffer {} with text: {:?}",
3434                        buffer.remote_id(),
3435                        buffer.text()
3436                    );
3437                    buffers.last().unwrap().clone()
3438                } else {
3439                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3440                };
3441
3442                let buffer = buffer_handle.read(cx);
3443                let buffer_text = buffer.text();
3444                let ranges = (0..rng.random_range(0..5))
3445                    .map(|_| {
3446                        let end_ix =
3447                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3448                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3449                        ExcerptRange::new(start_ix..end_ix)
3450                    })
3451                    .collect::<Vec<_>>();
3452                log::info!(
3453                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3454                    buffer_handle.read(cx).remote_id(),
3455                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3456                    ranges
3457                        .iter()
3458                        .map(|r| &buffer_text[r.context.clone()])
3459                        .collect::<Vec<_>>()
3460                );
3461
3462                let excerpt_id =
3463                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3464                log::info!("Inserted with ids: {:?}", excerpt_id);
3465            } else {
3466                let remove_count = rng.random_range(1..=excerpt_ids.len());
3467                let mut excerpts_to_remove = excerpt_ids
3468                    .choose_multiple(rng, remove_count)
3469                    .cloned()
3470                    .collect::<Vec<_>>();
3471                let snapshot = self.snapshot.borrow();
3472                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3473                drop(snapshot);
3474                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3475                self.remove_excerpts(excerpts_to_remove, cx);
3476            }
3477        }
3478    }
3479
3480    pub fn randomly_mutate(
3481        &mut self,
3482        rng: &mut impl rand::Rng,
3483        mutation_count: usize,
3484        cx: &mut Context<Self>,
3485    ) {
3486        use rand::prelude::*;
3487
3488        if rng.random_bool(0.7) || self.singleton {
3489            let buffer = self
3490                .buffers
3491                .values()
3492                .choose(rng)
3493                .map(|state| state.buffer.clone());
3494
3495            if let Some(buffer) = buffer {
3496                buffer.update(cx, |buffer, cx| {
3497                    if rng.random() {
3498                        buffer.randomly_edit(rng, mutation_count, cx);
3499                    } else {
3500                        buffer.randomly_undo_redo(rng, cx);
3501                    }
3502                });
3503            } else {
3504                self.randomly_edit(rng, mutation_count, cx);
3505            }
3506        } else {
3507            self.randomly_edit_excerpts(rng, mutation_count, cx);
3508        }
3509
3510        self.check_invariants(cx);
3511    }
3512
3513    fn check_invariants(&self, cx: &App) {
3514        self.read(cx).check_invariants();
3515    }
3516}
3517
3518impl EventEmitter<Event> for MultiBuffer {}
3519
3520impl MultiBufferSnapshot {
3521    pub fn text(&self) -> String {
3522        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3523            .map(|chunk| chunk.text)
3524            .collect()
3525    }
3526
3527    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3528        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3529            .flat_map(|c| c.chars().rev())
3530    }
3531
3532    fn reversed_chunks_in_range(
3533        &self,
3534        range: Range<MultiBufferOffset>,
3535    ) -> ReversedMultiBufferChunks<'_> {
3536        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3537        cursor.seek(&range.end);
3538        let current_chunks = cursor.region().as_ref().map(|region| {
3539            let start_overshoot = range.start.saturating_sub(region.range.start);
3540            let end_overshoot = range.end - region.range.start;
3541            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3542            let start = region.buffer_range.start + start_overshoot;
3543            region.buffer.reversed_chunks_in_range(start..end)
3544        });
3545        ReversedMultiBufferChunks {
3546            cursor,
3547            current_chunks,
3548            start: range.start,
3549            offset: range.end,
3550        }
3551    }
3552
3553    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3554        let offset = position.to_offset(self);
3555        self.text_for_range(offset..self.len())
3556            .flat_map(|chunk| chunk.chars())
3557    }
3558
3559    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3560        self.chunks(range, false).map(|chunk| chunk.text)
3561    }
3562
3563    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3564        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3565            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3566    }
3567
3568    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3569    where
3570        T: ToOffset,
3571    {
3572        let position = position.to_offset(self);
3573        position == self.clip_offset(position, Bias::Left)
3574            && self
3575                .bytes_in_range(position..self.len())
3576                .flatten()
3577                .copied()
3578                .take(needle.len())
3579                .eq(needle.bytes())
3580    }
3581
3582    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3583        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3584    }
3585
3586    pub fn diff_hunks_in_range<T: ToPoint>(
3587        &self,
3588        range: Range<T>,
3589    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3590        let query_range = range.start.to_point(self)..range.end.to_point(self);
3591        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3592            let diff = self.diffs.get(&buffer.remote_id())?;
3593            let iter = if let Some(main_buffer) = &diff.main_buffer {
3594                let buffer_start = buffer.point_to_offset(buffer_range.start);
3595                let buffer_end = buffer.point_to_offset(buffer_range.end);
3596                itertools::Either::Left(
3597                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3598                        .map(move |hunk| (hunk, buffer, true)),
3599                )
3600            } else {
3601                let buffer_start = buffer.anchor_before(buffer_range.start);
3602                let buffer_end = buffer.anchor_after(buffer_range.end);
3603                itertools::Either::Right(
3604                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3605                        .map(move |hunk| (hunk, buffer, false)),
3606                )
3607            };
3608            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3609                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3610                    return None;
3611                }
3612                let range = if is_inverted {
3613                    hunk.diff_base_byte_range.to_point(&buffer)
3614                } else {
3615                    hunk.range.clone()
3616                };
3617                Some((range, (hunk, is_inverted)))
3618            }))
3619        })
3620        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3621            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3622            {
3623                return None;
3624            }
3625            let end_row = if range.end.column == 0 {
3626                range.end.row
3627            } else {
3628                range.end.row + 1
3629            };
3630
3631            let word_diffs =
3632                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3633                    .then(|| {
3634                        let mut word_diffs = Vec::new();
3635
3636                        if self.show_deleted_hunks || is_inverted {
3637                            let hunk_start_offset = if is_inverted {
3638                                Anchor::text(
3639                                    excerpt.id,
3640                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3641                                )
3642                                .to_offset(self)
3643                            } else {
3644                                Anchor::text(excerpt.id, hunk.buffer_range.start).to_offset(self)
3645                            };
3646
3647                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3648                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3649                            }));
3650                        }
3651
3652                        if !is_inverted {
3653                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3654                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3655                            }));
3656                        }
3657                        word_diffs
3658                    })
3659                    .unwrap_or_default();
3660
3661            let buffer_range = if is_inverted {
3662                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3663                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3664            } else {
3665                hunk.buffer_range.clone()
3666            };
3667            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3668                DiffHunkStatusKind::Deleted
3669            } else if hunk.diff_base_byte_range.is_empty() {
3670                DiffHunkStatusKind::Added
3671            } else {
3672                DiffHunkStatusKind::Modified
3673            };
3674            Some(MultiBufferDiffHunk {
3675                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3676                buffer_id: excerpt.buffer_id,
3677                excerpt_id: excerpt.id,
3678                buffer_range,
3679                word_diffs,
3680                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3681                    ..BufferOffset(hunk.diff_base_byte_range.end),
3682                status: DiffHunkStatus {
3683                    kind: status_kind,
3684                    secondary: hunk.secondary_status,
3685                },
3686            })
3687        })
3688    }
3689
3690    fn excerpts_for_range<T: ToOffset>(
3691        &self,
3692        range: Range<T>,
3693    ) -> impl Iterator<Item = &Excerpt> + '_ {
3694        let range = range.start.to_offset(self)..range.end.to_offset(self);
3695        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3696        cursor.seek(&range.start);
3697        std::iter::from_fn(move || {
3698            let region = cursor.region()?;
3699            if region.range.start > range.end
3700                || region.range.start == range.end && region.range.start > range.start
3701            {
3702                return None;
3703            }
3704            let excerpt = region.excerpt;
3705            cursor.next_excerpt_forwards();
3706            Some(excerpt)
3707        })
3708    }
3709
3710    pub fn excerpt_ids_for_range<T: ToOffset>(
3711        &self,
3712        range: Range<T>,
3713    ) -> impl Iterator<Item = ExcerptId> + '_ {
3714        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3715    }
3716
3717    pub fn buffer_ids_for_range<T: ToOffset>(
3718        &self,
3719        range: Range<T>,
3720    ) -> impl Iterator<Item = BufferId> + '_ {
3721        self.excerpts_for_range(range)
3722            .map(|excerpt| excerpt.buffer_id)
3723    }
3724
3725    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3726    ///
3727    /// The passed in anchors must be ordered.
3728    pub fn text_anchors_to_visible_anchors(
3729        &self,
3730        anchors: impl IntoIterator<Item = text::Anchor>,
3731    ) -> Vec<Option<Anchor>> {
3732        let anchors = anchors.into_iter();
3733        let mut result = Vec::with_capacity(anchors.size_hint().0);
3734        let mut anchors = anchors.peekable();
3735        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
3736        'anchors: while let Some(anchor) = anchors.peek() {
3737            let Some(buffer_id) = anchor.buffer_id else {
3738                anchors.next();
3739                result.push(None);
3740                continue 'anchors;
3741            };
3742            let mut same_buffer_anchors =
3743                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3744
3745            if let Some(locators) = self.buffer_paths.get(&buffer_id) {
3746                let Some(mut next) = same_buffer_anchors.next() else {
3747                    continue 'anchors;
3748                };
3749                'excerpts: for locator in locators.iter() {
3750                    if cursor.seek_forward(&Some(locator), Bias::Left)
3751                        && let Some(excerpt) = cursor.item()
3752                    {
3753                        loop {
3754                            // anchor is before the first excerpt
3755                            if excerpt
3756                                .range
3757                                .context
3758                                .start
3759                                .cmp(&next, &excerpt.buffer)
3760                                .is_gt()
3761                            {
3762                                // so we skip it and try the next anchor
3763                                result.push(None);
3764                                match same_buffer_anchors.next() {
3765                                    Some(anchor) => next = anchor,
3766                                    None => continue 'anchors,
3767                                }
3768                            // anchor is within the excerpt
3769                            } else if excerpt
3770                                .range
3771                                .context
3772                                .end
3773                                .cmp(&next, &excerpt.buffer)
3774                                .is_ge()
3775                            {
3776                                // record it and all following anchors that are within
3777                                result.push(Some(Anchor::text(excerpt.id, next)));
3778                                result.extend(
3779                                    same_buffer_anchors
3780                                        .peeking_take_while(|a| {
3781                                            excerpt
3782                                                .range
3783                                                .context
3784                                                .end
3785                                                .cmp(a, &excerpt.buffer)
3786                                                .is_ge()
3787                                        })
3788                                        .map(|a| Some(Anchor::text(excerpt.id, a))),
3789                                );
3790                                match same_buffer_anchors.next() {
3791                                    Some(anchor) => next = anchor,
3792                                    None => continue 'anchors,
3793                                }
3794                            // anchor is after the excerpt, try the next one
3795                            } else {
3796                                continue 'excerpts;
3797                            }
3798                        }
3799                    }
3800                }
3801                // account for `next`
3802                result.push(None);
3803            }
3804            result.extend(same_buffer_anchors.map(|_| None));
3805        }
3806
3807        result
3808    }
3809
3810    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3811        &self,
3812        ranges: impl Iterator<Item = Range<T>>,
3813    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3814        ranges.flat_map(|range| {
3815            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3816                .into_iter()
3817        })
3818    }
3819
3820    pub fn range_to_buffer_ranges<R, T>(
3821        &self,
3822        range: R,
3823    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3824    where
3825        R: RangeBounds<T>,
3826        T: ToOffset,
3827    {
3828        self.range_to_buffer_ranges_with_context(range)
3829            .into_iter()
3830            .map(|(buffer, range, id, _context)| (buffer, range, id))
3831            .collect()
3832    }
3833
3834    pub fn range_to_buffer_ranges_with_context<R, T>(
3835        &self,
3836        range: R,
3837    ) -> Vec<(
3838        &BufferSnapshot,
3839        Range<BufferOffset>,
3840        ExcerptId,
3841        Range<text::Anchor>,
3842    )>
3843    where
3844        R: RangeBounds<T>,
3845        T: ToOffset,
3846    {
3847        let start = match range.start_bound() {
3848            Bound::Included(start) => start.to_offset(self),
3849            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3850            Bound::Unbounded => MultiBufferOffset::ZERO,
3851        };
3852        let end_bound = match range.end_bound() {
3853            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3854            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3855            Bound::Unbounded => Bound::Unbounded,
3856        };
3857        let bounds = (Bound::Included(start), end_bound);
3858
3859        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3860        cursor.seek(&start);
3861
3862        let mut result: Vec<(
3863            &BufferSnapshot,
3864            Range<BufferOffset>,
3865            ExcerptId,
3866            Range<text::Anchor>,
3867        )> = Vec::new();
3868        while let Some(region) = cursor.region() {
3869            let dominated_by_end_bound = match end_bound {
3870                Bound::Included(end) => region.range.start > end,
3871                Bound::Excluded(end) => region.range.start >= end,
3872                Bound::Unbounded => false,
3873            };
3874            if dominated_by_end_bound {
3875                break;
3876            }
3877            if region.is_main_buffer {
3878                let start_overshoot = start.saturating_sub(region.range.start);
3879                let end_offset = match end_bound {
3880                    Bound::Included(end) | Bound::Excluded(end) => end,
3881                    Bound::Unbounded => region.range.end,
3882                };
3883                let end_overshoot = end_offset.saturating_sub(region.range.start);
3884                let start = region
3885                    .buffer_range
3886                    .end
3887                    .min(region.buffer_range.start + start_overshoot);
3888                let end = region
3889                    .buffer_range
3890                    .end
3891                    .min(region.buffer_range.start + end_overshoot);
3892                let context = region.excerpt.range.context.clone();
3893                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3894                    *excerpt_id == region.excerpt.id && prev_range.end == start
3895                }) {
3896                    prev.1.end = end;
3897                } else {
3898                    result.push((region.buffer, start..end, region.excerpt.id, context));
3899                }
3900            }
3901            cursor.next();
3902        }
3903
3904        if let Some(excerpt) = cursor.excerpt() {
3905            let dominated_by_prev_excerpt =
3906                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3907            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3908                let excerpt_position = self.len();
3909                if bounds.contains(&excerpt_position) {
3910                    let buffer_offset =
3911                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3912                    let context = excerpt.range.context.clone();
3913                    result.push((
3914                        &excerpt.buffer,
3915                        buffer_offset..buffer_offset,
3916                        excerpt.id,
3917                        context,
3918                    ));
3919                }
3920            }
3921        }
3922
3923        result
3924    }
3925
3926    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3927        &self,
3928        range: Range<T>,
3929    ) -> impl Iterator<
3930        Item = (
3931            &BufferSnapshot,
3932            Range<BufferOffset>,
3933            ExcerptId,
3934            Option<Anchor>,
3935        ),
3936    > + '_ {
3937        let start = range.start.to_offset(self);
3938        let end = range.end.to_offset(self);
3939
3940        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3941        cursor.seek(&start);
3942
3943        std::iter::from_fn(move || {
3944            let region = cursor.region()?;
3945            if region.range.start > end {
3946                return None;
3947            }
3948            let start_overshoot = start.saturating_sub(region.range.start);
3949            let end_overshoot = end.saturating_sub(region.range.start);
3950            let start = region
3951                .buffer_range
3952                .end
3953                .min(region.buffer_range.start + start_overshoot);
3954            let end = region
3955                .buffer_range
3956                .end
3957                .min(region.buffer_range.start + end_overshoot);
3958
3959            let region_excerpt_id = region.excerpt.id;
3960            let deleted_hunk_anchor = if region.is_main_buffer {
3961                None
3962            } else {
3963                Some(self.anchor_before(region.range.start))
3964            };
3965            let result = (
3966                region.buffer,
3967                start..end,
3968                region_excerpt_id,
3969                deleted_hunk_anchor,
3970            );
3971            cursor.next();
3972            Some(result)
3973        })
3974    }
3975
3976    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3977    /// coordinates.
3978    ///
3979    /// The given callback will be called for every excerpt intersecting the given range. It will
3980    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3981    /// The callback should return an iterator of metadata items from that buffer, each paired
3982    /// with a buffer range.
3983    ///
3984    /// The returned iterator yields each of these metadata items, paired with its range in
3985    /// multi-buffer coordinates.
3986    fn lift_buffer_metadata<'a, MBD, M, I>(
3987        &'a self,
3988        query_range: Range<MBD>,
3989        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3990    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3991    where
3992        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3993        MBD: MultiBufferDimension
3994            + Ord
3995            + Sub<Output = MBD::TextDimension>
3996            + ops::Add<MBD::TextDimension, Output = MBD>
3997            + ops::AddAssign<MBD::TextDimension>,
3998        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3999            + ops::Add<Output = MBD::TextDimension>
4000            + AddAssign<MBD::TextDimension>
4001            + Ord,
4002    {
4003        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4004        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4005
4006        // Find the excerpt and buffer offset where the given range ends.
4007        cursor.seek(&query_range.end);
4008        let mut range_end = None;
4009        while let Some(region) = cursor.region() {
4010            if region.is_main_buffer {
4011                let mut buffer_end = region.buffer_range.start;
4012                let overshoot = if query_range.end > region.range.start {
4013                    query_range.end - region.range.start
4014                } else {
4015                    <MBD::TextDimension>::default()
4016                };
4017                buffer_end = buffer_end + overshoot;
4018                range_end = Some((region.excerpt.id, buffer_end));
4019                break;
4020            }
4021            cursor.next();
4022        }
4023
4024        cursor.seek(&query_range.start);
4025
4026        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4027            && region.range.start > MBD::default()
4028        {
4029            cursor.prev()
4030        } else if let Some(region) = cursor.region()
4031            && region.is_main_buffer
4032            && region.diff_hunk_status.is_some()
4033        {
4034            cursor.prev();
4035            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4036                cursor.next();
4037            }
4038        }
4039
4040        iter::from_fn(move || {
4041            loop {
4042                let excerpt = cursor.excerpt()?;
4043
4044                // If we have already retrieved metadata for this excerpt, continue to use it.
4045                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4046                    .as_mut()
4047                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4048                {
4049                    Some(metadata)
4050                }
4051                // Otherwise, compute the intersection of the input range with the excerpt's range,
4052                // and retrieve the metadata for the resulting range.
4053                else {
4054                    let region = cursor.region()?;
4055                    let mut buffer_start;
4056                    if region.is_main_buffer {
4057                        buffer_start = region.buffer_range.start;
4058                        if query_range.start > region.range.start {
4059                            let overshoot = query_range.start - region.range.start;
4060                            buffer_start = buffer_start + overshoot;
4061                        }
4062                        buffer_start = buffer_start.min(region.buffer_range.end);
4063                    } else {
4064                        buffer_start = cursor.main_buffer_position()?;
4065                    };
4066                    let mut buffer_end = excerpt
4067                        .range
4068                        .context
4069                        .end
4070                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4071                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4072                        && excerpt.id == end_excerpt_id
4073                    {
4074                        buffer_end = buffer_end.min(end_buffer_offset);
4075                    }
4076
4077                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4078                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4079                    })
4080                };
4081
4082                // Visit each metadata item.
4083                if let Some((metadata_buffer_range, metadata)) =
4084                    metadata_iter.and_then(Iterator::next)
4085                {
4086                    // Find the multibuffer regions that contain the start and end of
4087                    // the metadata item's range.
4088                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4089                        while let Some(region) = cursor.region() {
4090                            if (region.is_main_buffer
4091                                && (region.buffer_range.end >= metadata_buffer_range.start
4092                                    || cursor.is_at_end_of_excerpt()))
4093                                || (!region.is_main_buffer
4094                                    && region.buffer_range.start == metadata_buffer_range.start)
4095                            {
4096                                break;
4097                            }
4098                            cursor.next();
4099                        }
4100                    }
4101                    let start_region = cursor.region()?.clone();
4102                    while let Some(region) = cursor.region() {
4103                        if region.is_main_buffer
4104                            && (region.buffer_range.end > metadata_buffer_range.end
4105                                || cursor.is_at_end_of_excerpt())
4106                        {
4107                            break;
4108                        }
4109                        cursor.next();
4110                    }
4111                    let end_region = cursor.region();
4112
4113                    // Convert the metadata item's range into multibuffer coordinates.
4114                    let mut start_position = start_region.range.start;
4115                    let region_buffer_start = start_region.buffer_range.start;
4116                    if start_region.is_main_buffer
4117                        && metadata_buffer_range.start > region_buffer_start
4118                    {
4119                        start_position =
4120                            start_position + (metadata_buffer_range.start - region_buffer_start);
4121                        start_position = start_position.min(start_region.range.end);
4122                    }
4123
4124                    let mut end_position = self.max_position();
4125                    if let Some(end_region) = &end_region {
4126                        end_position = end_region.range.start;
4127                        debug_assert!(end_region.is_main_buffer);
4128                        let region_buffer_start = end_region.buffer_range.start;
4129                        if metadata_buffer_range.end > region_buffer_start {
4130                            end_position =
4131                                end_position + (metadata_buffer_range.end - region_buffer_start);
4132                        }
4133                        end_position = end_position.min(end_region.range.end);
4134                    }
4135
4136                    if start_position <= query_range.end && end_position >= query_range.start {
4137                        return Some((start_position..end_position, metadata, excerpt));
4138                    }
4139                }
4140                // When there are no more metadata items for this excerpt, move to the next excerpt.
4141                else {
4142                    current_excerpt_metadata.take();
4143                    if let Some((end_excerpt_id, _)) = range_end
4144                        && excerpt.id == end_excerpt_id
4145                    {
4146                        return None;
4147                    }
4148                    cursor.next_excerpt_forwards();
4149                }
4150            }
4151        })
4152    }
4153
4154    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4155        let offset = position.to_offset(self);
4156
4157        let mut cursor = self
4158            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4159            );
4160        cursor.seek(&DimensionPair {
4161            key: offset,
4162            value: None,
4163        });
4164        cursor.seek_to_start_of_current_excerpt();
4165        let excerpt = cursor.excerpt()?;
4166
4167        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4168        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4169        let current_position = self
4170            .anchor_before(offset)
4171            .text_anchor
4172            .to_offset(&excerpt.buffer);
4173
4174        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4175            if let Some(main_buffer) = &diff.main_buffer {
4176                for hunk in diff
4177                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4178                {
4179                    if hunk.diff_base_byte_range.end >= current_position {
4180                        continue;
4181                    }
4182                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4183                    let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4184                    return Some(MultiBufferRow(start.row));
4185                }
4186            } else {
4187                let excerpt_end = excerpt
4188                    .buffer
4189                    .anchor_before(excerpt_end.min(current_position));
4190                for hunk in diff.hunks_intersecting_range_rev(
4191                    excerpt.range.context.start..excerpt_end,
4192                    &excerpt.buffer,
4193                ) {
4194                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4195                    if hunk_end >= current_position {
4196                        continue;
4197                    }
4198                    let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4199                    return Some(MultiBufferRow(start.row));
4200                }
4201            }
4202        }
4203
4204        loop {
4205            cursor.prev_excerpt();
4206            let excerpt = cursor.excerpt()?;
4207
4208            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4209                continue;
4210            };
4211            if let Some(main_buffer) = &diff.main_buffer {
4212                let Some(hunk) = diff
4213                    .hunks_intersecting_base_text_range_rev(
4214                        excerpt.range.context.to_offset(&excerpt.buffer),
4215                        main_buffer,
4216                    )
4217                    .next()
4218                else {
4219                    continue;
4220                };
4221                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4222                let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4223                return Some(MultiBufferRow(start.row));
4224            } else {
4225                let Some(hunk) = diff
4226                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4227                    .next()
4228                else {
4229                    continue;
4230                };
4231                let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4232                return Some(MultiBufferRow(start.row));
4233            }
4234        }
4235    }
4236
4237    pub fn has_diff_hunks(&self) -> bool {
4238        self.diffs.values().any(|diff| !diff.is_empty())
4239    }
4240
4241    pub fn is_inside_word<T: ToOffset>(
4242        &self,
4243        position: T,
4244        scope_context: Option<CharScopeContext>,
4245    ) -> bool {
4246        let position = position.to_offset(self);
4247        let classifier = self
4248            .char_classifier_at(position)
4249            .scope_context(scope_context);
4250        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4251        let prev_char_kind = self
4252            .reversed_chars_at(position)
4253            .next()
4254            .map(|c| classifier.kind(c));
4255        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4256    }
4257
4258    pub fn surrounding_word<T: ToOffset>(
4259        &self,
4260        start: T,
4261        scope_context: Option<CharScopeContext>,
4262    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4263        let mut start = start.to_offset(self);
4264        let mut end = start;
4265        let mut next_chars = self.chars_at(start).peekable();
4266        let mut prev_chars = self.reversed_chars_at(start).peekable();
4267
4268        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4269
4270        let word_kind = cmp::max(
4271            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4272            next_chars.peek().copied().map(|c| classifier.kind(c)),
4273        );
4274
4275        for ch in prev_chars {
4276            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4277                start -= ch.len_utf8();
4278            } else {
4279                break;
4280            }
4281        }
4282
4283        for ch in next_chars {
4284            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4285                end += ch.len_utf8();
4286            } else {
4287                break;
4288            }
4289        }
4290
4291        (start..end, word_kind)
4292    }
4293
4294    pub fn char_kind_before<T: ToOffset>(
4295        &self,
4296        start: T,
4297        scope_context: Option<CharScopeContext>,
4298    ) -> Option<CharKind> {
4299        let start = start.to_offset(self);
4300        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4301        self.reversed_chars_at(start)
4302            .next()
4303            .map(|ch| classifier.kind(ch))
4304    }
4305
4306    pub fn is_singleton(&self) -> bool {
4307        self.singleton
4308    }
4309
4310    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4311        if self.singleton {
4312            self.excerpts
4313                .iter()
4314                .next()
4315                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4316        } else {
4317            None
4318        }
4319    }
4320
4321    pub fn len(&self) -> MultiBufferOffset {
4322        self.diff_transforms.summary().output.len
4323    }
4324
4325    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4326        MBD::from_summary(&self.text_summary())
4327    }
4328
4329    pub fn is_empty(&self) -> bool {
4330        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4331    }
4332
4333    pub fn widest_line_number(&self) -> u32 {
4334        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4335        self.excerpts.summary().widest_line_number + 1
4336    }
4337
4338    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4339        let range = range.start.to_offset(self)..range.end.to_offset(self);
4340        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4341        excerpts.seek(&range.start);
4342
4343        let mut chunk;
4344        let mut has_trailing_newline;
4345        let excerpt_bytes;
4346        if let Some(region) = excerpts.region() {
4347            let mut bytes = region.buffer.bytes_in_range(
4348                region.buffer_range.start + (range.start - region.range.start)
4349                    ..(region.buffer_range.start + (range.end - region.range.start))
4350                        .min(region.buffer_range.end),
4351            );
4352            chunk = bytes.next().unwrap_or(&[][..]);
4353            excerpt_bytes = Some(bytes);
4354            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4355            if chunk.is_empty() && has_trailing_newline {
4356                chunk = b"\n";
4357                has_trailing_newline = false;
4358            }
4359        } else {
4360            chunk = &[][..];
4361            excerpt_bytes = None;
4362            has_trailing_newline = false;
4363        };
4364
4365        MultiBufferBytes {
4366            range,
4367            cursor: excerpts,
4368            excerpt_bytes,
4369            has_trailing_newline,
4370            chunk,
4371        }
4372    }
4373
4374    pub fn reversed_bytes_in_range<T: ToOffset>(
4375        &self,
4376        range: Range<T>,
4377    ) -> ReversedMultiBufferBytes<'_> {
4378        let range = range.start.to_offset(self)..range.end.to_offset(self);
4379        let mut chunks = self.reversed_chunks_in_range(range.clone());
4380        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4381        ReversedMultiBufferBytes {
4382            range,
4383            chunks,
4384            chunk,
4385        }
4386    }
4387
4388    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4389        let mut cursor = self.cursor::<Point, Point>();
4390        cursor.seek(&Point::new(start_row.0, 0));
4391        let mut result = MultiBufferRows {
4392            point: Point::new(0, 0),
4393            is_empty: self.excerpts.is_empty(),
4394            is_singleton: self.is_singleton(),
4395            cursor,
4396        };
4397        result.seek(start_row);
4398        result
4399    }
4400
4401    pub fn chunks<T: ToOffset>(
4402        &self,
4403        range: Range<T>,
4404        language_aware: bool,
4405    ) -> MultiBufferChunks<'_> {
4406        let mut chunks = MultiBufferChunks {
4407            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4408                ..ExcerptDimension(MultiBufferOffset::ZERO),
4409            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4410            excerpts: self.excerpts.cursor(()),
4411            diff_transforms: self.diff_transforms.cursor(()),
4412            diffs: &self.diffs,
4413            diff_base_chunks: None,
4414            excerpt_chunks: None,
4415            buffer_chunk: None,
4416            language_aware,
4417        };
4418        let range = range.start.to_offset(self)..range.end.to_offset(self);
4419        chunks.seek(range);
4420        chunks
4421    }
4422
4423    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4424        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4425    }
4426
4427    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4428        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4429    }
4430
4431    pub fn clip_offset_utf16(
4432        &self,
4433        offset: MultiBufferOffsetUtf16,
4434        bias: Bias,
4435    ) -> MultiBufferOffsetUtf16 {
4436        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4437    }
4438
4439    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4440        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4441            buffer.clip_point_utf16(Unclipped(point), bias)
4442        })
4443    }
4444
4445    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4446        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4447    }
4448
4449    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4450        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4451    }
4452
4453    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4454        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4455    }
4456
4457    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4458        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4459    }
4460
4461    #[instrument(skip_all)]
4462    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4463        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4464    }
4465
4466    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4467        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4468    }
4469
4470    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4471        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4472    }
4473
4474    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4475        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4476    }
4477
4478    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4479        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4480    }
4481
4482    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4483        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4484    }
4485
4486    fn clip_dimension<MBD, BD>(
4487        &self,
4488        position: MBD,
4489        bias: Bias,
4490        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4491    ) -> MBD
4492    where
4493        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4494        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4495    {
4496        let mut cursor = self.cursor::<MBD, BD>();
4497        cursor.seek(&position);
4498        if let Some(region) = cursor.region() {
4499            if position >= region.range.end {
4500                return region.range.end;
4501            }
4502            let overshoot = position - region.range.start;
4503            let mut buffer_position = region.buffer_range.start;
4504            buffer_position += overshoot;
4505            let clipped_buffer_position =
4506                clip_buffer_position(region.buffer, buffer_position, bias);
4507            let mut position = region.range.start;
4508            position += clipped_buffer_position - region.buffer_range.start;
4509            position
4510        } else {
4511            self.max_position()
4512        }
4513    }
4514
4515    #[instrument(skip_all)]
4516    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4517        &self,
4518        key: MBR1,
4519        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4520    ) -> MBR2
4521    where
4522        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4523        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4524        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4525        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4526    {
4527        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4528        cursor.seek(&DimensionPair { key, value: None });
4529        if let Some(region) = cursor.region() {
4530            if key >= region.range.end.key {
4531                return region.range.end.value.unwrap();
4532            }
4533            let start_key = region.range.start.key;
4534            let start_value = region.range.start.value.unwrap();
4535            let buffer_start_key = region.buffer_range.start.key;
4536            let buffer_start_value = region.buffer_range.start.value.unwrap();
4537            let mut buffer_key = buffer_start_key;
4538            buffer_key += key - start_key;
4539            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4540            let mut result = start_value;
4541            result += buffer_value - buffer_start_value;
4542            result
4543        } else {
4544            self.max_position()
4545        }
4546    }
4547
4548    pub fn point_to_buffer_offset<T: ToOffset>(
4549        &self,
4550        point: T,
4551    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4552        let offset = point.to_offset(self);
4553        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4554        cursor.seek(&offset);
4555        let region = cursor.region()?;
4556        let overshoot = offset - region.range.start;
4557        let buffer_offset = region.buffer_range.start + overshoot;
4558        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4559            && region.has_trailing_newline
4560            && !region.is_main_buffer
4561        {
4562            let main_buffer_position = cursor.main_buffer_position()?;
4563            let buffer_snapshot = &cursor.excerpt()?.buffer;
4564            return Some((buffer_snapshot, main_buffer_position));
4565        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4566            return None;
4567        }
4568        Some((region.buffer, buffer_offset))
4569    }
4570
4571    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4572        let mut cursor = self.cursor::<Point, Point>();
4573        cursor.seek(&point);
4574        let region = cursor.region()?;
4575        let overshoot = point - region.range.start;
4576        let buffer_point = region.buffer_range.start + overshoot;
4577        let excerpt = cursor.excerpt()?;
4578        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4579            && region.has_trailing_newline
4580            && !region.is_main_buffer
4581        {
4582            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4583        } else if buffer_point > region.buffer.max_point() {
4584            return None;
4585        }
4586        Some((region.buffer, buffer_point))
4587    }
4588
4589    pub fn suggested_indents(
4590        &self,
4591        rows: impl IntoIterator<Item = u32>,
4592        cx: &App,
4593    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4594        let mut result = BTreeMap::new();
4595        self.suggested_indents_callback(
4596            rows,
4597            &mut |row, indent| {
4598                result.insert(row, indent);
4599                ControlFlow::Continue(())
4600            },
4601            cx,
4602        );
4603        result
4604    }
4605
4606    // move this to be a generator once those are a thing
4607    pub fn suggested_indents_callback(
4608        &self,
4609        rows: impl IntoIterator<Item = u32>,
4610        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4611        cx: &App,
4612    ) {
4613        let mut rows_for_excerpt = Vec::new();
4614        let mut cursor = self.cursor::<Point, Point>();
4615        let mut rows = rows.into_iter().peekable();
4616        let mut prev_row = u32::MAX;
4617        let mut prev_language_indent_size = IndentSize::default();
4618
4619        while let Some(row) = rows.next() {
4620            cursor.seek(&Point::new(row, 0));
4621            let Some(region) = cursor.region() else {
4622                continue;
4623            };
4624
4625            // Retrieve the language and indent size once for each disjoint region being indented.
4626            let single_indent_size = if row.saturating_sub(1) == prev_row {
4627                prev_language_indent_size
4628            } else {
4629                region
4630                    .buffer
4631                    .language_indent_size_at(Point::new(row, 0), cx)
4632            };
4633            prev_language_indent_size = single_indent_size;
4634            prev_row = row;
4635
4636            let start_buffer_row = region.buffer_range.start.row;
4637            let start_multibuffer_row = region.range.start.row;
4638            let end_multibuffer_row = region.range.end.row;
4639
4640            rows_for_excerpt.push(row);
4641            while let Some(next_row) = rows.peek().copied() {
4642                if end_multibuffer_row > next_row {
4643                    rows_for_excerpt.push(next_row);
4644                    rows.next();
4645                } else {
4646                    break;
4647                }
4648            }
4649
4650            let buffer_rows = rows_for_excerpt
4651                .drain(..)
4652                .map(|row| start_buffer_row + row - start_multibuffer_row);
4653            let buffer_indents = region
4654                .buffer
4655                .suggested_indents(buffer_rows, single_indent_size);
4656            for (row, indent) in buffer_indents {
4657                if cb(
4658                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4659                    indent,
4660                )
4661                .is_break()
4662                {
4663                    return;
4664                }
4665            }
4666        }
4667    }
4668
4669    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4670        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4671            let mut size = buffer.indent_size_for_line(range.start.row);
4672            size.len = size
4673                .len
4674                .min(range.end.column)
4675                .saturating_sub(range.start.column);
4676            size
4677        } else {
4678            IndentSize::spaces(0)
4679        }
4680    }
4681
4682    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4683        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4684            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4685        } else {
4686            LineIndent::spaces(0)
4687        }
4688    }
4689
4690    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4691        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4692
4693        if self.language_settings(cx).extend_comment_on_newline
4694            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4695        {
4696            let delimiters = language_scope.line_comment_prefixes();
4697            for delimiter in delimiters {
4698                if *self
4699                    .chars_at(Point::new(row.0, indent.len() as u32))
4700                    .take(delimiter.chars().count())
4701                    .collect::<String>()
4702                    .as_str()
4703                    == **delimiter
4704                {
4705                    indent.push_str(delimiter);
4706                    break;
4707                }
4708            }
4709        }
4710
4711        indent
4712    }
4713
4714    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4715    where
4716        T: ToOffset,
4717    {
4718        for char in self.reversed_chars_at(position) {
4719            if !char.is_whitespace() {
4720                return false;
4721            }
4722            if char == '\n' {
4723                return true;
4724            }
4725        }
4726        true
4727    }
4728
4729    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4730        while row.0 > 0 {
4731            row.0 -= 1;
4732            if !self.is_line_blank(row) {
4733                return Some(row);
4734            }
4735        }
4736        None
4737    }
4738
4739    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4740        if let Some((_, range)) = self.buffer_line_for_row(row) {
4741            range.end.column - range.start.column
4742        } else {
4743            0
4744        }
4745    }
4746
4747    pub fn buffer_line_for_row(
4748        &self,
4749        row: MultiBufferRow,
4750    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4751        let mut cursor = self.cursor::<Point, Point>();
4752        let point = Point::new(row.0, 0);
4753        cursor.seek(&point);
4754        let region = cursor.region()?;
4755        let overshoot = point.min(region.range.end) - region.range.start;
4756        let buffer_point = region.buffer_range.start + overshoot;
4757        if buffer_point.row > region.buffer_range.end.row {
4758            return None;
4759        }
4760        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4761        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4762            .min(region.buffer_range.end);
4763        Some((region.buffer, line_start..line_end))
4764    }
4765
4766    pub fn max_point(&self) -> Point {
4767        self.text_summary().lines
4768    }
4769
4770    pub fn max_row(&self) -> MultiBufferRow {
4771        MultiBufferRow(self.text_summary().lines.row)
4772    }
4773
4774    pub fn text_summary(&self) -> MBTextSummary {
4775        self.diff_transforms.summary().output
4776    }
4777
4778    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4779    where
4780        MBD: MultiBufferDimension + AddAssign,
4781        O: ToOffset,
4782    {
4783        let range = range.start.to_offset(self)..range.end.to_offset(self);
4784        let mut cursor = self
4785            .diff_transforms
4786            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4787        cursor.seek(&range.start, Bias::Right);
4788
4789        let Some(first_transform) = cursor.item() else {
4790            return MBD::from_summary(&MBTextSummary::default());
4791        };
4792
4793        let diff_transform_start = cursor.start().0;
4794        let diff_transform_end = cursor.end().0;
4795        let diff_start = range.start;
4796        let start_overshoot = diff_start - diff_transform_start;
4797        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4798
4799        let mut result = match first_transform {
4800            DiffTransform::BufferContent { .. } => {
4801                let excerpt_start = cursor.start().1 + start_overshoot;
4802                let excerpt_end = cursor.start().1 + end_overshoot;
4803                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4804            }
4805            DiffTransform::DeletedHunk {
4806                buffer_id,
4807                base_text_byte_range,
4808                has_trailing_newline,
4809                ..
4810            } => {
4811                let buffer_start = base_text_byte_range.start + start_overshoot;
4812                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4813                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4814                    panic!("{:?} is in non-existent deleted hunk", range.start)
4815                };
4816
4817                let include_trailing_newline =
4818                    *has_trailing_newline && range.end >= diff_transform_end;
4819                if include_trailing_newline {
4820                    buffer_end -= 1;
4821                }
4822
4823                let mut summary = base_text
4824                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4825
4826                if include_trailing_newline {
4827                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4828                        &TextSummary::newline(),
4829                    ))
4830                }
4831
4832                let mut result = MBD::default();
4833                result.add_text_dim(&summary);
4834                result
4835            }
4836        };
4837        if range.end < diff_transform_end {
4838            return result;
4839        }
4840
4841        cursor.next();
4842        result.add_mb_text_summary(
4843            &cursor
4844                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4845                .0,
4846        );
4847
4848        let Some(last_transform) = cursor.item() else {
4849            return result;
4850        };
4851
4852        let overshoot = range.end - cursor.start().0;
4853        let suffix = match last_transform {
4854            DiffTransform::BufferContent { .. } => {
4855                let end = cursor.start().1 + overshoot;
4856                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4857            }
4858            DiffTransform::DeletedHunk {
4859                base_text_byte_range,
4860                buffer_id,
4861                has_trailing_newline,
4862                ..
4863            } => {
4864                let buffer_end = base_text_byte_range.start + overshoot;
4865                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4866                    panic!("{:?} is in non-existent deleted hunk", range.end)
4867                };
4868
4869                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4870                    base_text_byte_range.start..buffer_end,
4871                );
4872                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4873                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4874                        &TextSummary::from("\n"),
4875                    ))
4876                }
4877
4878                let mut result = MBD::default();
4879                result.add_text_dim(&suffix);
4880                result
4881            }
4882        };
4883
4884        result += suffix;
4885        result
4886    }
4887
4888    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4889    where
4890        MBD: MultiBufferDimension + AddAssign,
4891    {
4892        let mut summary = MBD::default();
4893        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4894        cursor.seek(&range.start, Bias::Right);
4895        if let Some(excerpt) = cursor.item() {
4896            let mut end_before_newline = cursor.end();
4897            if excerpt.has_trailing_newline {
4898                end_before_newline -= 1;
4899            }
4900
4901            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4902            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4903            let end_in_excerpt =
4904                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4905            summary.add_text_dim(
4906                &excerpt
4907                    .buffer
4908                    .text_summary_for_range::<MBD::TextDimension, _>(
4909                        start_in_excerpt..end_in_excerpt,
4910                    ),
4911            );
4912
4913            if range.end > end_before_newline {
4914                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4915            }
4916
4917            cursor.next();
4918        }
4919
4920        if range.end > *cursor.start() {
4921            summary += cursor
4922                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4923                .0;
4924            if let Some(excerpt) = cursor.item() {
4925                range.end = cmp::max(*cursor.start(), range.end);
4926
4927                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4928                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4929                summary.add_text_dim(
4930                    &excerpt
4931                        .buffer
4932                        .text_summary_for_range::<MBD::TextDimension, _>(
4933                            excerpt_start..end_in_excerpt,
4934                        ),
4935                );
4936            }
4937        }
4938
4939        summary
4940    }
4941
4942    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4943    where
4944        MBD: MultiBufferDimension
4945            + Ord
4946            + Sub<Output = MBD::TextDimension>
4947            + Sub<MBD::TextDimension, Output = MBD>
4948            + AddAssign<MBD::TextDimension>
4949            + Add<MBD::TextDimension, Output = MBD>,
4950        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4951    {
4952        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4953        let locator = self.excerpt_locator_for_id(excerpt_id);
4954        let (start, _, mut item) = self
4955            .excerpts
4956            .find::<ExcerptSummary, _>((), locator, Bias::Left);
4957        let mut start = MBD::from_summary(&start.text);
4958        if item.is_none() && excerpt_id == ExcerptId::max() {
4959            item = self.excerpts.last();
4960            if let Some(last_summary) = self.excerpts.last_summary() {
4961                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
4962            }
4963        }
4964
4965        let excerpt_start_position = ExcerptDimension(start);
4966        if self.diff_transforms.is_empty() {
4967            if let Some(excerpt) = item {
4968                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4969                    return excerpt_start_position.0;
4970                }
4971                let excerpt_buffer_start = excerpt
4972                    .range
4973                    .context
4974                    .start
4975                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4976                let excerpt_buffer_end = excerpt
4977                    .range
4978                    .context
4979                    .end
4980                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4981                let buffer_summary = anchor
4982                    .text_anchor
4983                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4984                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4985                let mut position = excerpt_start_position;
4986                if summary > excerpt_buffer_start {
4987                    position += summary - excerpt_buffer_start;
4988                }
4989
4990                position.0
4991            } else {
4992                excerpt_start_position.0
4993            }
4994        } else {
4995            let mut diff_transforms_cursor = self
4996                .diff_transforms
4997                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4998            diff_transforms_cursor.next();
4999
5000            if let Some(excerpt) = item {
5001                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5002                    return self.resolve_summary_for_min_or_max_anchor(
5003                        &Anchor::min(),
5004                        excerpt_start_position,
5005                        &mut diff_transforms_cursor,
5006                    );
5007                }
5008                let excerpt_buffer_start = excerpt
5009                    .range
5010                    .context
5011                    .start
5012                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5013                let excerpt_buffer_end = excerpt
5014                    .range
5015                    .context
5016                    .end
5017                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5018                let buffer_summary = anchor
5019                    .text_anchor
5020                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5021                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5022                let mut position = excerpt_start_position;
5023                if summary > excerpt_buffer_start {
5024                    position += summary - excerpt_buffer_start;
5025                }
5026
5027                if diff_transforms_cursor.start().0 < position {
5028                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5029                }
5030                self.resolve_summary_for_anchor(
5031                    &anchor,
5032                    position,
5033                    &mut diff_transforms_cursor,
5034                    &excerpt.buffer,
5035                )
5036            } else {
5037                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5038                self.resolve_summary_for_min_or_max_anchor(
5039                    &Anchor::max(),
5040                    excerpt_start_position,
5041                    &mut diff_transforms_cursor,
5042                )
5043            }
5044        }
5045    }
5046
5047    /// Maps an anchor's excerpt-space position to its output-space position by
5048    /// walking the diff transforms. The cursor is shared across consecutive
5049    /// calls, so it may already be partway through the transform list.
5050    fn resolve_summary_for_anchor<MBD>(
5051        &self,
5052        anchor: &Anchor,
5053        excerpt_position: ExcerptDimension<MBD>,
5054        diff_transforms: &mut Cursor<
5055            DiffTransform,
5056            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5057        >,
5058        excerpt_buffer: &text::BufferSnapshot,
5059    ) -> MBD
5060    where
5061        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5062    {
5063        loop {
5064            let transform_end_position = diff_transforms.end().0;
5065            let item = diff_transforms.item();
5066            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5067
5068            // A right-biased anchor at a transform boundary belongs to the
5069            // *next* transform, so advance past the current one.
5070            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5071                diff_transforms.next();
5072                continue;
5073            }
5074
5075            let mut position = diff_transforms.start().1;
5076            match item {
5077                Some(DiffTransform::DeletedHunk {
5078                    buffer_id,
5079                    base_text_byte_range,
5080                    hunk_info,
5081                    ..
5082                }) => {
5083                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5084                        && let Some(base_text) =
5085                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5086                        && diff_base_anchor.is_valid(&base_text)
5087                    {
5088                        // The anchor carries a diff-base position — resolve it
5089                        // to a location inside the deleted hunk.
5090                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5091                        if base_text_offset >= base_text_byte_range.start
5092                            && base_text_offset <= base_text_byte_range.end
5093                        {
5094                            let position_in_hunk = base_text
5095                                .text_summary_for_range::<MBD::TextDimension, _>(
5096                                    base_text_byte_range.start..base_text_offset,
5097                                );
5098                            position.0.add_text_dim(&position_in_hunk);
5099                        } else if at_transform_end {
5100                            // diff_base offset falls outside this hunk's range;
5101                            // advance to see if the next transform is a better fit.
5102                            diff_transforms.next();
5103                            continue;
5104                        }
5105                    } else if at_transform_end
5106                        && anchor
5107                            .text_anchor
5108                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5109                            .is_gt()
5110                    {
5111                        // The anchor has no (valid) diff-base position, so it
5112                        // belongs in the buffer content, not in the deleted
5113                        // hunk. However, after an edit deletes the text between
5114                        // the hunk boundary and this anchor, both resolve to
5115                        // the same excerpt_position—landing us here on the
5116                        // DeletedHunk left behind by the shared cursor. Use the
5117                        // CRDT ordering to detect that the anchor is strictly
5118                        // *past* the hunk boundary and skip to the following
5119                        // BufferContent.
5120                        diff_transforms.next();
5121                        continue;
5122                    }
5123                }
5124                _ => {
5125                    // On a BufferContent (or no transform). If the anchor
5126                    // carries a diff_base_anchor it needs a DeletedHunk, so
5127                    // advance to find one.
5128                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5129                        diff_transforms.next();
5130                        continue;
5131                    }
5132                    let overshoot = excerpt_position - diff_transforms.start().0;
5133                    position += overshoot;
5134                }
5135            }
5136
5137            return position.0;
5138        }
5139    }
5140
5141    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5142    fn resolve_summary_for_min_or_max_anchor<MBD>(
5143        &self,
5144        anchor: &Anchor,
5145        excerpt_position: ExcerptDimension<MBD>,
5146        diff_transforms: &mut Cursor<
5147            DiffTransform,
5148            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5149        >,
5150    ) -> MBD
5151    where
5152        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5153    {
5154        loop {
5155            let transform_end_position = diff_transforms.end().0;
5156            let item = diff_transforms.item();
5157            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5158
5159            // A right-biased anchor at a transform boundary belongs to the
5160            // *next* transform, so advance past the current one.
5161            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5162                diff_transforms.next();
5163                continue;
5164            }
5165
5166            let mut position = diff_transforms.start().1;
5167            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5168                let overshoot = excerpt_position - diff_transforms.start().0;
5169                position += overshoot;
5170            }
5171
5172            return position.0;
5173        }
5174    }
5175
5176    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5177        let mut cursor = self
5178            .excerpts
5179            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5180        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5181
5182        cursor.seek(&Some(locator), Bias::Left);
5183        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5184            cursor.prev();
5185        }
5186
5187        let mut position = cursor.start().1;
5188        if let Some(excerpt) = cursor.item()
5189            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5190        {
5191            let excerpt_buffer_start = excerpt
5192                .buffer
5193                .offset_for_anchor(&excerpt.range.context.start);
5194            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5195            let buffer_position = cmp::min(
5196                excerpt_buffer_end,
5197                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5198            );
5199            if buffer_position > excerpt_buffer_start {
5200                position += buffer_position - excerpt_buffer_start;
5201            }
5202        }
5203        position
5204    }
5205
5206    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5207        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5208            excerpt_id = *replacement;
5209        }
5210        excerpt_id
5211    }
5212
5213    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5214    where
5215        MBD: MultiBufferDimension
5216            + Ord
5217            + Sub<Output = MBD::TextDimension>
5218            + AddAssign<MBD::TextDimension>,
5219        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5220        I: 'a + IntoIterator<Item = &'a Anchor>,
5221    {
5222        let mut anchors = anchors.into_iter().peekable();
5223        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5224        let mut diff_transforms_cursor = self
5225            .diff_transforms
5226            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5227        diff_transforms_cursor.next();
5228
5229        let mut summaries = Vec::new();
5230        while let Some(anchor) = anchors.peek() {
5231            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5232
5233            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5234                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5235            });
5236
5237            let locator = self.excerpt_locator_for_id(excerpt_id);
5238            cursor.seek_forward(locator, Bias::Left);
5239            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5240                cursor.prev();
5241            }
5242
5243            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5244            if let Some(excerpt) = cursor.item() {
5245                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5246                    let position = self.resolve_summary_for_min_or_max_anchor(
5247                        &Anchor::min(),
5248                        excerpt_start_position,
5249                        &mut diff_transforms_cursor,
5250                    );
5251                    summaries.extend(excerpt_anchors.map(|_| position));
5252                    continue;
5253                }
5254                let excerpt_buffer_start = excerpt
5255                    .range
5256                    .context
5257                    .start
5258                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5259                let excerpt_buffer_end = excerpt
5260                    .range
5261                    .context
5262                    .end
5263                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5264                for (buffer_summary, anchor) in excerpt
5265                    .buffer
5266                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5267                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5268                    )
5269                {
5270                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5271                    let mut position = excerpt_start_position;
5272                    if summary > excerpt_buffer_start {
5273                        position += summary - excerpt_buffer_start;
5274                    }
5275
5276                    if diff_transforms_cursor.start().0 < position {
5277                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5278                    }
5279
5280                    summaries.push(self.resolve_summary_for_anchor(
5281                        anchor,
5282                        position,
5283                        &mut diff_transforms_cursor,
5284                        &excerpt.buffer,
5285                    ));
5286                }
5287            } else {
5288                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5289                let position = self.resolve_summary_for_min_or_max_anchor(
5290                    &Anchor::max(),
5291                    excerpt_start_position,
5292                    &mut diff_transforms_cursor,
5293                );
5294                summaries.extend(excerpt_anchors.map(|_| position));
5295            }
5296        }
5297
5298        summaries
5299    }
5300
5301    pub fn dimensions_from_points<'a, MBD>(
5302        &'a self,
5303        points: impl 'a + IntoIterator<Item = Point>,
5304    ) -> impl 'a + Iterator<Item = MBD>
5305    where
5306        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5307    {
5308        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5309        cursor.seek(&DimensionPair {
5310            key: Point::default(),
5311            value: None,
5312        });
5313        let mut points = points.into_iter();
5314        iter::from_fn(move || {
5315            let point = points.next()?;
5316
5317            cursor.seek_forward(&DimensionPair {
5318                key: point,
5319                value: None,
5320            });
5321
5322            if let Some(region) = cursor.region() {
5323                let overshoot = point - region.range.start.key;
5324                let buffer_point = region.buffer_range.start + overshoot;
5325                let mut position = region.range.start.value.unwrap();
5326                position.add_text_dim(
5327                    &region
5328                        .buffer
5329                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5330                );
5331                if point == region.range.end.key && region.has_trailing_newline {
5332                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5333                }
5334                Some(position)
5335            } else {
5336                Some(MBD::from_summary(&self.text_summary()))
5337            }
5338        })
5339    }
5340
5341    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5342    where
5343        I: 'a + IntoIterator<Item = &'a Anchor>,
5344    {
5345        let mut anchors = anchors.into_iter().enumerate().peekable();
5346        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5347        cursor.next();
5348
5349        let mut result = Vec::new();
5350
5351        while let Some((_, anchor)) = anchors.peek() {
5352            let old_excerpt_id = anchor.excerpt_id;
5353
5354            // Find the location where this anchor's excerpt should be.
5355            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5356            cursor.seek_forward(&Some(old_locator), Bias::Left);
5357
5358            let next_excerpt = cursor.item();
5359            let prev_excerpt = cursor.prev_item();
5360
5361            // Process all of the anchors for this excerpt.
5362            while let Some((anchor_ix, &anchor)) =
5363                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5364            {
5365                let mut anchor = anchor;
5366
5367                // Leave min and max anchors unchanged if invalid or
5368                // if the old excerpt still exists at this location
5369                let mut kept_position = next_excerpt
5370                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5371                    || old_excerpt_id == ExcerptId::max()
5372                    || old_excerpt_id == ExcerptId::min();
5373
5374                // If the old excerpt no longer exists at this location, then attempt to
5375                // find an equivalent position for this anchor in an adjacent excerpt.
5376                if !kept_position {
5377                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5378                        if excerpt.contains(&anchor) {
5379                            anchor.excerpt_id = excerpt.id;
5380                            kept_position = true;
5381                            break;
5382                        }
5383                    }
5384                }
5385
5386                // If there's no adjacent excerpt that contains the anchor's position,
5387                // then report that the anchor has lost its position.
5388                if !kept_position {
5389                    anchor = if let Some(excerpt) = next_excerpt {
5390                        let mut text_anchor = excerpt
5391                            .range
5392                            .context
5393                            .start
5394                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5395                        if text_anchor
5396                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5397                            .is_gt()
5398                        {
5399                            text_anchor = excerpt.range.context.end;
5400                        }
5401                        Anchor::text(excerpt.id, text_anchor)
5402                    } else if let Some(excerpt) = prev_excerpt {
5403                        let mut text_anchor = excerpt
5404                            .range
5405                            .context
5406                            .end
5407                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5408                        if text_anchor
5409                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5410                            .is_lt()
5411                        {
5412                            text_anchor = excerpt.range.context.start;
5413                        }
5414                        Anchor::text(excerpt.id, text_anchor)
5415                    } else if anchor.text_anchor.bias == Bias::Left {
5416                        Anchor::min()
5417                    } else {
5418                        Anchor::max()
5419                    };
5420                }
5421
5422                result.push((anchor_ix, anchor, kept_position));
5423            }
5424        }
5425        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5426        result
5427    }
5428
5429    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5430        self.anchor_at(position, Bias::Left)
5431    }
5432
5433    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5434        self.anchor_at(position, Bias::Right)
5435    }
5436
5437    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5438        let offset = position.to_offset(self);
5439
5440        // Find the given position in the diff transforms. Determine the corresponding
5441        // offset in the excerpts, and whether the position is within a deleted hunk.
5442        let mut diff_transforms = self
5443            .diff_transforms
5444            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5445        diff_transforms.seek(&offset, Bias::Right);
5446
5447        if offset == diff_transforms.start().0
5448            && bias == Bias::Left
5449            && let Some(prev_item) = diff_transforms.prev_item()
5450            && let DiffTransform::DeletedHunk { .. } = prev_item
5451        {
5452            diff_transforms.prev();
5453        }
5454        let offset_in_transform = offset - diff_transforms.start().0;
5455        let mut excerpt_offset = diff_transforms.start().1;
5456        let mut diff_base_anchor = None;
5457        if let Some(DiffTransform::DeletedHunk {
5458            buffer_id,
5459            base_text_byte_range,
5460            has_trailing_newline,
5461            ..
5462        }) = diff_transforms.item()
5463        {
5464            let diff = self.diffs.get(buffer_id).expect("missing diff");
5465            if offset_in_transform > base_text_byte_range.len() {
5466                debug_assert!(*has_trailing_newline);
5467                bias = Bias::Right;
5468            } else {
5469                diff_base_anchor = Some(
5470                    diff.base_text()
5471                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5472                );
5473                bias = Bias::Left;
5474            }
5475        } else {
5476            excerpt_offset += MultiBufferOffset(offset_in_transform);
5477        };
5478
5479        let mut excerpts = self
5480            .excerpts
5481            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5482        excerpts.seek(&excerpt_offset, Bias::Right);
5483        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5484            excerpts.prev();
5485        }
5486        if let Some(excerpt) = excerpts.item() {
5487            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5488            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5489                overshoot -= 1;
5490                bias = Bias::Right;
5491            }
5492
5493            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5494            let text_anchor =
5495                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5496            let anchor = Anchor::text(excerpt.id, text_anchor);
5497            match diff_base_anchor {
5498                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5499                None => anchor,
5500            }
5501        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5502        {
5503            Anchor::min()
5504        } else {
5505            Anchor::max()
5506        }
5507    }
5508
5509    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5510    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5511        let (excerpt, buffer, _) = self.as_singleton()?;
5512        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5513            Some(Anchor::text(excerpt, text_anchor))
5514        } else {
5515            None
5516        }
5517    }
5518
5519    /// Returns an anchor for the given excerpt and text anchor,
5520    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5521    pub fn anchor_range_in_excerpt(
5522        &self,
5523        excerpt_id: ExcerptId,
5524        text_anchor: Range<text::Anchor>,
5525    ) -> Option<Range<Anchor>> {
5526        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5527
5528        Some(
5529            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5530                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5531        )
5532    }
5533
5534    /// Returns an anchor for the given excerpt and text anchor,
5535    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5536    pub fn anchor_in_excerpt(
5537        &self,
5538        excerpt_id: ExcerptId,
5539        text_anchor: text::Anchor,
5540    ) -> Option<Anchor> {
5541        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5542        Self::anchor_in_excerpt_(excerpt, text_anchor)
5543    }
5544
5545    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5546    pub fn anchors_in_excerpt(
5547        &self,
5548        excerpt_id: ExcerptId,
5549        text_anchors: impl IntoIterator<Item = text::Anchor>,
5550    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5551        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5552        Some(
5553            text_anchors
5554                .into_iter()
5555                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5556        )
5557    }
5558
5559    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5560        match text_anchor.buffer_id {
5561            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5562            Some(_) => return None,
5563            None if text_anchor.is_max() || text_anchor.is_min() => {
5564                return Some(Anchor::text(excerpt.id, text_anchor));
5565            }
5566            None => return None,
5567        }
5568
5569        let context = &excerpt.range.context;
5570        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5571            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5572        {
5573            return None;
5574        }
5575
5576        Some(Anchor::text(excerpt.id, text_anchor))
5577    }
5578
5579    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5580        Some(self.excerpt(excerpt_id)?.range.context.clone())
5581    }
5582
5583    pub fn excerpt_range_for_excerpt(
5584        &self,
5585        excerpt_id: ExcerptId,
5586    ) -> Option<ExcerptRange<text::Anchor>> {
5587        Some(self.excerpt(excerpt_id)?.range.clone())
5588    }
5589
5590    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5591        if anchor.is_min() || anchor.is_max() {
5592            // todo(lw): should be `!self.is_empty()`
5593            true
5594        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5595            excerpt.buffer.can_resolve(&anchor.text_anchor)
5596        } else {
5597            false
5598        }
5599    }
5600
5601    pub fn excerpts(
5602        &self,
5603    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5604        self.excerpts
5605            .iter()
5606            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5607    }
5608
5609    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5610    where
5611        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5612        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5613    {
5614        let excerpts = self.excerpts.cursor(());
5615        let diff_transforms = self.diff_transforms.cursor(());
5616        MultiBufferCursor {
5617            excerpts,
5618            diff_transforms,
5619            diffs: &self.diffs,
5620            cached_region: OnceCell::new(),
5621        }
5622    }
5623
5624    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5625        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5626        let mut excerpts = self
5627            .excerpts
5628            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5629        excerpts.seek(&Some(start_locator), Bias::Left);
5630        excerpts.prev();
5631
5632        let mut diff_transforms = self
5633            .diff_transforms
5634            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5635        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5636        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5637            diff_transforms.next();
5638        }
5639
5640        let excerpt = excerpts.item()?;
5641        Some(MultiBufferExcerpt {
5642            excerpt,
5643            offset: diff_transforms.start().output_dimension.0,
5644            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5645            excerpt_offset: excerpts.start().1,
5646            diff_transforms,
5647        })
5648    }
5649
5650    pub fn excerpt_boundaries_in_range<R, T>(
5651        &self,
5652        range: R,
5653    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5654    where
5655        R: RangeBounds<T>,
5656        T: ToOffset,
5657    {
5658        let start_offset;
5659        let start = match range.start_bound() {
5660            Bound::Included(start) => {
5661                start_offset = start.to_offset(self);
5662                Bound::Included(start_offset)
5663            }
5664            Bound::Excluded(_) => {
5665                panic!("not supported")
5666            }
5667            Bound::Unbounded => {
5668                start_offset = MultiBufferOffset::ZERO;
5669                Bound::Unbounded
5670            }
5671        };
5672        let end = match range.end_bound() {
5673            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5674            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5675            Bound::Unbounded => Bound::Unbounded,
5676        };
5677        let bounds = (start, end);
5678        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5679        cursor.seek(&DimensionPair {
5680            key: start_offset,
5681            value: None,
5682        });
5683
5684        if cursor
5685            .fetch_excerpt_with_range()
5686            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5687        {
5688            cursor.prev_excerpt();
5689        } else {
5690            cursor.seek_to_start_of_current_excerpt();
5691        }
5692        let mut prev_region = cursor
5693            .fetch_excerpt_with_range()
5694            .map(|(excerpt, _)| excerpt);
5695
5696        cursor.next_excerpt_forwards();
5697
5698        iter::from_fn(move || {
5699            loop {
5700                if self.singleton {
5701                    return None;
5702                }
5703
5704                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5705                cursor.next_excerpt_forwards();
5706                if !bounds.contains(&next_range.start.key) {
5707                    prev_region = Some(next_excerpt);
5708                    continue;
5709                }
5710
5711                let next_region_start = next_range.start.value.unwrap();
5712                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5713                    range.start.value.unwrap()
5714                } else {
5715                    self.max_point()
5716                };
5717
5718                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5719                    id: region.id,
5720                    buffer: region.buffer.clone(),
5721                    buffer_id: region.buffer_id,
5722                    range: region.range.clone(),
5723                    end_row: MultiBufferRow(next_region_start.row),
5724                });
5725
5726                let next = ExcerptBoundaryInfo {
5727                    id: next_excerpt.id,
5728                    buffer: next_excerpt.buffer.clone(),
5729                    buffer_id: next_excerpt.buffer_id,
5730                    range: next_excerpt.range.clone(),
5731                    end_row: if next_excerpt.has_trailing_newline {
5732                        MultiBufferRow(next_region_end.row - 1)
5733                    } else {
5734                        MultiBufferRow(next_region_end.row)
5735                    },
5736                };
5737
5738                let row = MultiBufferRow(next_region_start.row);
5739
5740                prev_region = Some(next_excerpt);
5741
5742                return Some(ExcerptBoundary { row, prev, next });
5743            }
5744        })
5745    }
5746
5747    pub fn edit_count(&self) -> usize {
5748        self.edit_count
5749    }
5750
5751    pub fn non_text_state_update_count(&self) -> usize {
5752        self.non_text_state_update_count
5753    }
5754
5755    /// Returns the smallest enclosing bracket ranges containing the given range or
5756    /// None if no brackets contain range or the range is not contained in a single
5757    /// excerpt
5758    ///
5759    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5760    #[ztracing::instrument(skip_all)]
5761    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5762        &self,
5763        range: Range<T>,
5764        range_filter: Option<
5765            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5766        >,
5767    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5768        let range = range.start.to_offset(self)..range.end.to_offset(self);
5769        let mut excerpt = self.excerpt_containing(range.clone())?;
5770        let buffer = excerpt.buffer();
5771        let excerpt_buffer_range = excerpt.buffer_range();
5772
5773        // Filter to ranges contained in the excerpt
5774        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5775            excerpt_buffer_range.contains(&BufferOffset(open.start))
5776                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5777                && range_filter.is_none_or(|filter| {
5778                    filter(
5779                        buffer,
5780                        BufferOffset(open.start)..BufferOffset(close.end),
5781                        BufferOffset(close.start)..BufferOffset(close.end),
5782                    )
5783                })
5784        };
5785
5786        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5787            excerpt.map_range_to_buffer(range),
5788            Some(&range_filter),
5789        )?;
5790
5791        Some((
5792            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5793            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5794        ))
5795    }
5796
5797    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5798    /// not contained in a single excerpt
5799    pub fn enclosing_bracket_ranges<T: ToOffset>(
5800        &self,
5801        range: Range<T>,
5802    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5803    {
5804        let range = range.start.to_offset(self)..range.end.to_offset(self);
5805        let mut excerpt = self.excerpt_containing(range.clone())?;
5806
5807        Some(
5808            excerpt
5809                .buffer()
5810                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5811                .filter_map(move |pair| {
5812                    let open_range =
5813                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5814                    let close_range =
5815                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5816                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5817                        Some((
5818                            excerpt.map_range_from_buffer(open_range),
5819                            excerpt.map_range_from_buffer(close_range),
5820                        ))
5821                    } else {
5822                        None
5823                    }
5824                }),
5825        )
5826    }
5827
5828    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5829    /// not contained in a single excerpt
5830    pub fn text_object_ranges<T: ToOffset>(
5831        &self,
5832        range: Range<T>,
5833        options: TreeSitterOptions,
5834    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5835        let range = range.start.to_offset(self)..range.end.to_offset(self);
5836        self.excerpt_containing(range.clone())
5837            .map(|mut excerpt| {
5838                excerpt
5839                    .buffer()
5840                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5841                    .filter_map(move |(range, text_object)| {
5842                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5843                        if excerpt.contains_buffer_range(range.clone()) {
5844                            Some((excerpt.map_range_from_buffer(range), text_object))
5845                        } else {
5846                            None
5847                        }
5848                    })
5849            })
5850            .into_iter()
5851            .flatten()
5852    }
5853
5854    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5855    /// not contained in a single excerpt
5856    pub fn bracket_ranges<T: ToOffset>(
5857        &self,
5858        range: Range<T>,
5859    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5860    {
5861        let range = range.start.to_offset(self)..range.end.to_offset(self);
5862        let mut excerpt = self.excerpt_containing(range.clone())?;
5863        Some(
5864            excerpt
5865                .buffer()
5866                .bracket_ranges(excerpt.map_range_to_buffer(range))
5867                .filter_map(move |pair| {
5868                    let open_range =
5869                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5870                    let close_range =
5871                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5872                    excerpt
5873                        .contains_buffer_range(open_range.start..close_range.end)
5874                        .then(|| BracketMatch {
5875                            open_range: excerpt.map_range_from_buffer(open_range),
5876                            close_range: excerpt.map_range_from_buffer(close_range),
5877                            color_index: pair.color_index,
5878                            newline_only: pair.newline_only,
5879                            syntax_layer_depth: pair.syntax_layer_depth,
5880                        })
5881                })
5882                .map(BracketMatch::bracket_ranges),
5883        )
5884    }
5885
5886    pub fn redacted_ranges<'a, T: ToOffset>(
5887        &'a self,
5888        range: Range<T>,
5889        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5890    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5891        let range = range.start.to_offset(self)..range.end.to_offset(self);
5892        self.lift_buffer_metadata(range, move |buffer, range| {
5893            if redaction_enabled(buffer.file()) {
5894                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5895            } else {
5896                None
5897            }
5898        })
5899        .map(|(range, _, _)| range)
5900    }
5901
5902    pub fn runnable_ranges(
5903        &self,
5904        range: Range<Anchor>,
5905    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5906        let range = range.start.to_offset(self)..range.end.to_offset(self);
5907        self.lift_buffer_metadata(range, move |buffer, range| {
5908            Some(
5909                buffer
5910                    .runnable_ranges(range.clone())
5911                    .filter(move |runnable| {
5912                        runnable.run_range.start >= range.start
5913                            && runnable.run_range.end < range.end
5914                    })
5915                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5916            )
5917        })
5918        .map(|(run_range, runnable, _)| (run_range, runnable))
5919    }
5920
5921    pub fn line_indents(
5922        &self,
5923        start_row: MultiBufferRow,
5924        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5925    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5926        let max_point = self.max_point();
5927        let mut cursor = self.cursor::<Point, Point>();
5928        cursor.seek(&Point::new(start_row.0, 0));
5929        iter::from_fn(move || {
5930            let mut region = cursor.region()?;
5931            while !buffer_filter(&region.excerpt.buffer) {
5932                cursor.next();
5933                region = cursor.region()?;
5934            }
5935            let region = cursor.region()?;
5936            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5937            let buffer_start_row =
5938                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5939
5940            let buffer_end_row = if region.is_main_buffer
5941                && (region.has_trailing_newline || region.range.end == max_point)
5942            {
5943                region.buffer_range.end.row
5944            } else {
5945                region.buffer_range.end.row.saturating_sub(1)
5946            };
5947
5948            let line_indents = region
5949                .buffer
5950                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5951            let region_buffer_row = region.buffer_range.start.row;
5952            let region_row = region.range.start.row;
5953            let region_buffer = &region.excerpt.buffer;
5954            cursor.next();
5955            Some(line_indents.map(move |(buffer_row, indent)| {
5956                let row = region_row + (buffer_row - region_buffer_row);
5957                (MultiBufferRow(row), indent, region_buffer.as_ref())
5958            }))
5959        })
5960        .flatten()
5961    }
5962
5963    pub fn reversed_line_indents(
5964        &self,
5965        end_row: MultiBufferRow,
5966        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5967    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5968        let max_point = self.max_point();
5969        let mut cursor = self.cursor::<Point, Point>();
5970        cursor.seek(&Point::new(end_row.0, 0));
5971        iter::from_fn(move || {
5972            let mut region = cursor.region()?;
5973            while !buffer_filter(&region.excerpt.buffer) {
5974                cursor.prev();
5975                region = cursor.region()?;
5976            }
5977            let region = cursor.region()?;
5978
5979            let buffer_start_row = region.buffer_range.start.row;
5980            let buffer_end_row = if region.is_main_buffer
5981                && (region.has_trailing_newline || region.range.end == max_point)
5982            {
5983                region.buffer_range.end.row + 1
5984            } else {
5985                region.buffer_range.end.row
5986            };
5987
5988            let overshoot = end_row.0 - region.range.start.row;
5989            let buffer_end_row =
5990                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5991
5992            let line_indents = region
5993                .buffer
5994                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5995            let region_buffer_row = region.buffer_range.start.row;
5996            let region_row = region.range.start.row;
5997            let region_buffer = &region.excerpt.buffer;
5998            cursor.prev();
5999            Some(line_indents.map(move |(buffer_row, indent)| {
6000                let row = region_row + (buffer_row - region_buffer_row);
6001                (MultiBufferRow(row), indent, region_buffer.as_ref())
6002            }))
6003        })
6004        .flatten()
6005    }
6006
6007    pub async fn enclosing_indent(
6008        &self,
6009        mut target_row: MultiBufferRow,
6010    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6011        let max_row = MultiBufferRow(self.max_point().row);
6012        if target_row >= max_row {
6013            return None;
6014        }
6015
6016        let mut target_indent = self.line_indent_for_row(target_row);
6017
6018        // If the current row is at the start of an indented block, we want to return this
6019        // block as the enclosing indent.
6020        if !target_indent.is_line_empty() && target_row < max_row {
6021            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6022            if !next_line_indent.is_line_empty()
6023                && target_indent.raw_len() < next_line_indent.raw_len()
6024            {
6025                target_indent = next_line_indent;
6026                target_row.0 += 1;
6027            }
6028        }
6029
6030        const SEARCH_ROW_LIMIT: u32 = 25000;
6031        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6032        const YIELD_INTERVAL: u32 = 100;
6033
6034        let mut accessed_row_counter = 0;
6035
6036        // If there is a blank line at the current row, search for the next non indented lines
6037        if target_indent.is_line_empty() {
6038            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6039            let end =
6040                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6041
6042            let mut non_empty_line_above = None;
6043            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6044                if row < start {
6045                    break;
6046                }
6047                accessed_row_counter += 1;
6048                if accessed_row_counter == YIELD_INTERVAL {
6049                    accessed_row_counter = 0;
6050                    yield_now().await;
6051                }
6052                if !indent.is_line_empty() {
6053                    non_empty_line_above = Some((row, indent));
6054                    break;
6055                }
6056            }
6057
6058            let mut non_empty_line_below = None;
6059            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6060                if row > end {
6061                    break;
6062                }
6063                accessed_row_counter += 1;
6064                if accessed_row_counter == YIELD_INTERVAL {
6065                    accessed_row_counter = 0;
6066                    yield_now().await;
6067                }
6068                if !indent.is_line_empty() {
6069                    non_empty_line_below = Some((row, indent));
6070                    break;
6071                }
6072            }
6073
6074            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6075                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6076                    if above_indent.raw_len() >= below_indent.raw_len() {
6077                        (above_row, above_indent)
6078                    } else {
6079                        (below_row, below_indent)
6080                    }
6081                }
6082                (Some(above), None) => above,
6083                (None, Some(below)) => below,
6084                _ => return None,
6085            };
6086
6087            target_indent = indent;
6088            target_row = row;
6089        }
6090
6091        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6092        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6093
6094        let mut start_indent = None;
6095        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6096            if row < start {
6097                break;
6098            }
6099            accessed_row_counter += 1;
6100            if accessed_row_counter == YIELD_INTERVAL {
6101                accessed_row_counter = 0;
6102                yield_now().await;
6103            }
6104            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6105                start_indent = Some((row, indent));
6106                break;
6107            }
6108        }
6109        let (start_row, start_indent_size) = start_indent?;
6110
6111        let mut end_indent = (end, None);
6112        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6113            if row > end {
6114                break;
6115            }
6116            accessed_row_counter += 1;
6117            if accessed_row_counter == YIELD_INTERVAL {
6118                accessed_row_counter = 0;
6119                yield_now().await;
6120            }
6121            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6122                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6123                break;
6124            }
6125        }
6126        let (end_row, end_indent_size) = end_indent;
6127
6128        let indent = if let Some(end_indent_size) = end_indent_size {
6129            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6130                start_indent_size
6131            } else {
6132                end_indent_size
6133            }
6134        } else {
6135            start_indent_size
6136        };
6137
6138        Some((start_row..end_row, indent))
6139    }
6140
6141    pub fn indent_guides_in_range<T: ToPoint>(
6142        &self,
6143        range: Range<T>,
6144        ignore_disabled_for_language: bool,
6145        cx: &App,
6146    ) -> impl Iterator<Item = IndentGuide> {
6147        let range = range.start.to_point(self)..range.end.to_point(self);
6148        let start_row = MultiBufferRow(range.start.row);
6149        let end_row = MultiBufferRow(range.end.row);
6150
6151        let mut row_indents = self.line_indents(start_row, |buffer| {
6152            let settings =
6153                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6154            settings.indent_guides.enabled || ignore_disabled_for_language
6155        });
6156
6157        let mut result = Vec::new();
6158        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6159
6160        let mut prev_settings = None;
6161        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6162            if first_row > end_row {
6163                break;
6164            }
6165            let current_depth = indent_stack.len() as u32;
6166
6167            // Avoid retrieving the language settings repeatedly for every buffer row.
6168            if let Some((prev_buffer_id, _)) = &prev_settings
6169                && prev_buffer_id != &buffer.remote_id()
6170            {
6171                prev_settings.take();
6172            }
6173            let settings = &prev_settings
6174                .get_or_insert_with(|| {
6175                    (
6176                        buffer.remote_id(),
6177                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6178                    )
6179                })
6180                .1;
6181            let tab_size = settings.tab_size.get();
6182
6183            // When encountering empty, continue until found useful line indent
6184            // then add to the indent stack with the depth found
6185            let mut found_indent = false;
6186            let mut last_row = first_row;
6187            if line_indent.is_line_blank() {
6188                while !found_indent {
6189                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6190                        break;
6191                    };
6192                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6193                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6194                        break;
6195                    }
6196
6197                    if new_line_indent.is_line_blank() {
6198                        continue;
6199                    }
6200                    last_row = target_row.min(end_row);
6201                    line_indent = new_line_indent;
6202                    found_indent = true;
6203                    break;
6204                }
6205            } else {
6206                found_indent = true
6207            }
6208
6209            let depth = if found_indent {
6210                line_indent.len(tab_size) / tab_size
6211            } else {
6212                0
6213            };
6214
6215            match depth.cmp(&current_depth) {
6216                cmp::Ordering::Less => {
6217                    for _ in 0..(current_depth - depth) {
6218                        let mut indent = indent_stack.pop().unwrap();
6219                        if last_row != first_row {
6220                            // In this case, we landed on an empty row, had to seek forward,
6221                            // and discovered that the indent we where on is ending.
6222                            // This means that the last display row must
6223                            // be on line that ends this indent range, so we
6224                            // should display the range up to the first non-empty line
6225                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6226                        }
6227
6228                        result.push(indent)
6229                    }
6230                }
6231                cmp::Ordering::Greater => {
6232                    for next_depth in current_depth..depth {
6233                        indent_stack.push(IndentGuide {
6234                            buffer_id: buffer.remote_id(),
6235                            start_row: first_row,
6236                            end_row: last_row,
6237                            depth: next_depth,
6238                            tab_size,
6239                            settings: settings.indent_guides.clone(),
6240                        });
6241                    }
6242                }
6243                _ => {}
6244            }
6245
6246            for indent in indent_stack.iter_mut() {
6247                indent.end_row = last_row;
6248            }
6249        }
6250
6251        result.extend(indent_stack);
6252        result.into_iter()
6253    }
6254
6255    pub fn trailing_excerpt_update_count(&self) -> usize {
6256        self.trailing_excerpt_update_count
6257    }
6258
6259    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6260        self.point_to_buffer_offset(point)
6261            .and_then(|(buffer, _)| buffer.file())
6262    }
6263
6264    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6265        self.point_to_buffer_offset(offset)
6266            .and_then(|(buffer, offset)| buffer.language_at(offset))
6267    }
6268
6269    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6270        self.excerpts
6271            .first()
6272            .map(|excerpt| &excerpt.buffer)
6273            .map(|buffer| {
6274                language_settings(
6275                    buffer.language().map(|language| language.name()),
6276                    buffer.file(),
6277                    cx,
6278                )
6279            })
6280            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6281    }
6282
6283    pub fn language_settings_at<'a, T: ToOffset>(
6284        &'a self,
6285        point: T,
6286        cx: &'a App,
6287    ) -> Cow<'a, LanguageSettings> {
6288        let mut language = None;
6289        let mut file = None;
6290        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6291            language = buffer.language_at(offset);
6292            file = buffer.file();
6293        }
6294        language_settings(language.map(|l| l.name()), file, cx)
6295    }
6296
6297    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6298        self.point_to_buffer_offset(point)
6299            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6300    }
6301
6302    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6303        self.point_to_buffer_offset(point)
6304            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6305            .unwrap_or_default()
6306    }
6307
6308    pub fn language_indent_size_at<T: ToOffset>(
6309        &self,
6310        position: T,
6311        cx: &App,
6312    ) -> Option<IndentSize> {
6313        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6314        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6315    }
6316
6317    pub fn is_dirty(&self) -> bool {
6318        self.is_dirty
6319    }
6320
6321    pub fn has_deleted_file(&self) -> bool {
6322        self.has_deleted_file
6323    }
6324
6325    pub fn has_conflict(&self) -> bool {
6326        self.has_conflict
6327    }
6328
6329    pub fn has_diagnostics(&self) -> bool {
6330        self.excerpts
6331            .iter()
6332            .any(|excerpt| excerpt.buffer.has_diagnostics())
6333    }
6334
6335    pub fn diagnostic_group(
6336        &self,
6337        buffer_id: BufferId,
6338        group_id: usize,
6339    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6340        self.lift_buffer_metadata::<Point, _, _>(
6341            Point::zero()..self.max_point(),
6342            move |buffer, range| {
6343                if buffer.remote_id() != buffer_id {
6344                    return None;
6345                };
6346                Some(
6347                    buffer
6348                        .diagnostics_in_range(range, false)
6349                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6350                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6351                )
6352            },
6353        )
6354        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6355    }
6356
6357    pub fn diagnostics_in_range<'a, MBD>(
6358        &'a self,
6359        range: Range<MBD>,
6360    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6361    where
6362        MBD::TextDimension: 'a
6363            + text::ToOffset
6364            + text::FromAnchor
6365            + Sub<Output = MBD::TextDimension>
6366            + fmt::Debug
6367            + ops::Add<Output = MBD::TextDimension>
6368            + ops::AddAssign
6369            + Ord,
6370        MBD: MultiBufferDimension
6371            + Ord
6372            + Sub<Output = MBD::TextDimension>
6373            + ops::Add<MBD::TextDimension, Output = MBD>
6374            + ops::AddAssign<MBD::TextDimension>
6375            + 'a,
6376    {
6377        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6378            Some(
6379                buffer
6380                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6381                    .map(|entry| (entry.range, entry.diagnostic)),
6382            )
6383        })
6384        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6385    }
6386
6387    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6388        &'a self,
6389        range: Range<MBD>,
6390    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6391    where
6392        MBD: MultiBufferDimension
6393            + Ord
6394            + Sub<Output = MBD::TextDimension>
6395            + ops::Add<MBD::TextDimension, Output = MBD>
6396            + ops::AddAssign<MBD::TextDimension>,
6397        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6398            + ops::Add<Output = MBD::TextDimension>
6399            + text::ToOffset
6400            + text::FromAnchor
6401            + AddAssign<MBD::TextDimension>
6402            + Ord,
6403    {
6404        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6405            Some(
6406                buffer
6407                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6408                    .map(|entry| (entry.range, entry.diagnostic)),
6409            )
6410        })
6411        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6412    }
6413
6414    pub fn syntax_ancestor<T: ToOffset>(
6415        &self,
6416        range: Range<T>,
6417    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6418        let range = range.start.to_offset(self)..range.end.to_offset(self);
6419        let mut excerpt = self.excerpt_containing(range.clone())?;
6420        let node = excerpt
6421            .buffer()
6422            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6423        let node_range = node.byte_range();
6424        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6425        if !excerpt.contains_buffer_range(node_range.clone()) {
6426            return None;
6427        };
6428        Some((node, excerpt.map_range_from_buffer(node_range)))
6429    }
6430
6431    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6432        let (excerpt_id, _, buffer) = self.as_singleton()?;
6433        let outline = buffer.outline(theme);
6434        Some(Outline::new(
6435            outline
6436                .items
6437                .into_iter()
6438                .flat_map(|item| {
6439                    Some(OutlineItem {
6440                        depth: item.depth,
6441                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6442                        source_range_for_text: self
6443                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6444                        text: item.text,
6445                        highlight_ranges: item.highlight_ranges,
6446                        name_ranges: item.name_ranges,
6447                        body_range: item.body_range.and_then(|body_range| {
6448                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6449                        }),
6450                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6451                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6452                        }),
6453                    })
6454                })
6455                .collect(),
6456        ))
6457    }
6458
6459    pub fn symbols_containing<T: ToOffset>(
6460        &self,
6461        offset: T,
6462        theme: Option<&SyntaxTheme>,
6463    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6464        let anchor = self.anchor_before(offset);
6465        let excerpt @ &Excerpt {
6466            id: excerpt_id,
6467            buffer_id,
6468            ref buffer,
6469            ..
6470        } = self.excerpt(anchor.excerpt_id)?;
6471        if cfg!(debug_assertions) {
6472            match anchor.text_anchor.buffer_id {
6473                // we clearly are hitting this according to sentry, but in what situations can this occur?
6474                Some(anchor_buffer_id) => {
6475                    assert_eq!(
6476                        anchor_buffer_id, buffer_id,
6477                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6478                    )
6479                }
6480                None => assert!(anchor.is_max()),
6481            }
6482        };
6483        Some((
6484            buffer_id,
6485            buffer
6486                .symbols_containing(anchor.text_anchor, theme)
6487                .into_iter()
6488                .flat_map(|item| {
6489                    Some(OutlineItem {
6490                        depth: item.depth,
6491                        source_range_for_text: Anchor::range_in_buffer(
6492                            excerpt_id,
6493                            item.source_range_for_text,
6494                        ),
6495                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6496                        text: item.text,
6497                        highlight_ranges: item.highlight_ranges,
6498                        name_ranges: item.name_ranges,
6499                        body_range: item
6500                            .body_range
6501                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6502                        annotation_range: item
6503                            .annotation_range
6504                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6505                    })
6506                })
6507                .collect(),
6508        ))
6509    }
6510
6511    fn anchor_seek_target(&self, anchor: Anchor) -> Option<AnchorSeekTarget> {
6512        match anchor {
6513            Anchor::Min => Some(AnchorSeekTarget::Min),
6514            Anchor::Max => Some(AnchorSeekTarget::Max),
6515            Anchor::Text { buffer_id, .. } => {
6516                let Some(path_key) = self.path_for_buffer(buffer_id) else {
6517                    return None;
6518                };
6519                let Some(snapshot) = self.buffer_for_path(path_key) else {
6520                    return None;
6521                };
6522
6523                Some(AnchorSeekTarget::Text {
6524                    path_key: path_key.clone(),
6525                    anchor: anchor.text_anchor().unwrap(),
6526                    snapshot: snapshot.clone(),
6527                })
6528            }
6529        }
6530    }
6531
6532    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6533        self.try_excerpt_locator_for_id(id)
6534            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6535    }
6536
6537    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6538        if id == ExcerptId::min() {
6539            Some(Locator::min_ref())
6540        } else if id == ExcerptId::max() {
6541            Some(Locator::max_ref())
6542        } else {
6543            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6544            if let Some(entry) = item
6545                && entry.id == id
6546            {
6547                return Some(&entry.locator);
6548            }
6549            None
6550        }
6551    }
6552
6553    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6554    fn excerpt_locators_for_ids(
6555        &self,
6556        ids: impl IntoIterator<Item = ExcerptId>,
6557    ) -> SmallVec<[Locator; 1]> {
6558        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6559        sorted_ids.sort_unstable();
6560        sorted_ids.dedup();
6561        let mut locators = SmallVec::new();
6562
6563        while sorted_ids.last() == Some(&ExcerptId::max()) {
6564            sorted_ids.pop();
6565            locators.push(Locator::max());
6566        }
6567
6568        let mut sorted_ids = sorted_ids.into_iter().peekable();
6569        locators.extend(
6570            sorted_ids
6571                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6572                .map(|_| Locator::min()),
6573        );
6574
6575        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6576        for id in sorted_ids {
6577            if cursor.seek_forward(&id, Bias::Left) {
6578                locators.push(cursor.item().unwrap().locator.clone());
6579            } else {
6580                panic!("invalid excerpt id {:?}", id);
6581            }
6582        }
6583
6584        locators.sort_unstable();
6585        locators
6586    }
6587
6588    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6589        Some(self.excerpt(excerpt_id)?.buffer_id)
6590    }
6591
6592    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6593        Some(&self.excerpt(excerpt_id)?.buffer)
6594    }
6595
6596    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6597        todo!()
6598    }
6599
6600    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6601        self.path_keys.get(&buffer_id)
6602    }
6603
6604    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6605        self.buffer_for_path(self.path_keys.get(&id)?)
6606    }
6607
6608    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6609        let mut cursor = self
6610            .excerpts
6611            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6612        let locator = self.excerpt_locator_for_id(excerpt_id);
6613        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6614        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6615            sought_exact = true;
6616            cursor.prev();
6617        } else if excerpt_id == ExcerptId::min() {
6618            sought_exact = true;
6619        }
6620        if sought_exact {
6621            let start = cursor.start().1;
6622            let end = cursor.end().1;
6623            let mut diff_transforms = self
6624                .diff_transforms
6625                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6626            diff_transforms.seek(&start, Bias::Left);
6627            let overshoot = start - diff_transforms.start().0;
6628            let start = diff_transforms.start().1 + overshoot;
6629            diff_transforms.seek(&end, Bias::Right);
6630            let overshoot = end - diff_transforms.start().0;
6631            let end = diff_transforms.start().1 + overshoot;
6632            Some(start.0..end.0)
6633        } else {
6634            None
6635        }
6636    }
6637
6638    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6639    /// to have the latest excerpt id for the one passed in and will also remap
6640    /// `ExcerptId::max()` to the corresponding excertp ID.
6641    ///
6642    /// Callers of this function should generally use the resulting excerpt's `id` field
6643    /// afterwards.
6644    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6645        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6646        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
6647        let (_, _, item) =
6648            self.excerpts
6649                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
6650        if let Some(excerpt) = item
6651            && excerpt.id == excerpt_id
6652        {
6653            return Some(excerpt);
6654        } else if item.is_none() && excerpt_id == ExcerptId::max() {
6655            return self.excerpts.last();
6656        }
6657        None
6658    }
6659
6660    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6661    pub fn excerpt_containing<T: ToOffset>(
6662        &self,
6663        range: Range<T>,
6664    ) -> Option<MultiBufferExcerpt<'_>> {
6665        let range = range.start.to_offset(self)..range.end.to_offset(self);
6666        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6667        cursor.seek(&range.start);
6668
6669        let start_excerpt = cursor.excerpt()?;
6670        if range.end != range.start {
6671            cursor.seek_forward(&range.end);
6672            if cursor.excerpt()?.id != start_excerpt.id {
6673                return None;
6674            }
6675        }
6676
6677        cursor.seek_to_start_of_current_excerpt();
6678        let region = cursor.region()?;
6679        let offset = region.range.start;
6680        let buffer_offset = start_excerpt.buffer_start_offset();
6681        let excerpt_offset = *cursor.excerpts.start();
6682        Some(MultiBufferExcerpt {
6683            diff_transforms: cursor.diff_transforms,
6684            excerpt: start_excerpt,
6685            offset,
6686            buffer_offset,
6687            excerpt_offset,
6688        })
6689    }
6690
6691    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6692        if let Some(id) = anchor.text_anchor.buffer_id {
6693            return Some(id);
6694        }
6695        let excerpt = self.excerpt_containing(anchor..anchor)?;
6696        Some(excerpt.buffer_id())
6697    }
6698
6699    pub fn selections_in_range<'a>(
6700        &'a self,
6701        range: &'a Range<Anchor>,
6702        include_local: bool,
6703    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6704        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6705        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6706        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6707        cursor.seek(start_locator, Bias::Left);
6708        cursor
6709            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6710            .flat_map(move |excerpt| {
6711                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6712                if excerpt.id == range.start.excerpt_id {
6713                    query_range.start = range.start.text_anchor;
6714                }
6715                if excerpt.id == range.end.excerpt_id {
6716                    query_range.end = range.end.text_anchor;
6717                }
6718
6719                excerpt
6720                    .buffer
6721                    .selections_in_range(query_range, include_local)
6722                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6723                        selections.map(move |selection| {
6724                            let mut start = Anchor::text(excerpt.id, selection.start);
6725                            let mut end = Anchor::text(excerpt.id, selection.end);
6726                            if range.start.cmp(&start, self).is_gt() {
6727                                start = range.start;
6728                            }
6729                            if range.end.cmp(&end, self).is_lt() {
6730                                end = range.end;
6731                            }
6732
6733                            (
6734                                replica_id,
6735                                line_mode,
6736                                cursor_shape,
6737                                Selection {
6738                                    id: selection.id,
6739                                    start,
6740                                    end,
6741                                    reversed: selection.reversed,
6742                                    goal: selection.goal,
6743                                },
6744                            )
6745                        })
6746                    })
6747            })
6748    }
6749
6750    pub fn show_headers(&self) -> bool {
6751        self.show_headers
6752    }
6753
6754    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6755        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6756    }
6757
6758    pub fn all_diff_hunks_expanded(&self) -> bool {
6759        self.all_diff_hunks_expanded
6760    }
6761
6762    /// Visually annotates a position or range with the `Debug` representation of a value. The
6763    /// callsite of this function is used as a key - previous annotations will be removed.
6764    #[cfg(debug_assertions)]
6765    #[track_caller]
6766    pub fn debug<V, R>(&self, ranges: &R, value: V)
6767    where
6768        R: debug::ToMultiBufferDebugRanges,
6769        V: std::fmt::Debug,
6770    {
6771        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6772    }
6773
6774    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6775    /// debug annotations with the same key will be removed. The key is also used to determine the
6776    /// annotation's color.
6777    #[cfg(debug_assertions)]
6778    #[track_caller]
6779    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6780    where
6781        K: std::hash::Hash + 'static,
6782        R: debug::ToMultiBufferDebugRanges,
6783        V: std::fmt::Debug,
6784    {
6785        let text_ranges = ranges
6786            .to_multi_buffer_debug_ranges(self)
6787            .into_iter()
6788            .flat_map(|range| {
6789                self.range_to_buffer_ranges(range.start..=range.end)
6790                    .into_iter()
6791                    .map(|(buffer, range, _excerpt_id)| {
6792                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6793                    })
6794            })
6795            .collect();
6796        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6797            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6798        });
6799    }
6800
6801    fn excerpt_edits_for_diff_change(
6802        &self,
6803        buffer_state: &BufferState,
6804        diff_change_range: Range<usize>,
6805    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6806        let mut excerpt_edits = Vec::new();
6807        for locator in &buffer_state.excerpts {
6808            let mut cursor = self
6809                .excerpts
6810                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6811            cursor.seek_forward(&Some(locator), Bias::Left);
6812            if let Some(excerpt) = cursor.item()
6813                && excerpt.locator == *locator
6814            {
6815                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6816                if diff_change_range.end < excerpt_buffer_range.start
6817                    || diff_change_range.start > excerpt_buffer_range.end
6818                {
6819                    continue;
6820                }
6821                let excerpt_start = cursor.start().1;
6822                let excerpt_len = excerpt.text_summary.len;
6823                let diff_change_start_in_excerpt = diff_change_range
6824                    .start
6825                    .saturating_sub(excerpt_buffer_range.start);
6826                let diff_change_end_in_excerpt = diff_change_range
6827                    .end
6828                    .saturating_sub(excerpt_buffer_range.start);
6829                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6830                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6831                excerpt_edits.push(Edit {
6832                    old: edit_start..edit_end,
6833                    new: edit_start..edit_end,
6834                });
6835            }
6836        }
6837        excerpt_edits
6838    }
6839
6840    fn path_key_for_anchor(&self, anchor: Anchor) -> Option<PathKey> {
6841        todo!()
6842    }
6843}
6844
6845#[cfg(any(test, feature = "test-support"))]
6846impl MultiBufferSnapshot {
6847    pub fn random_byte_range(
6848        &self,
6849        start_offset: MultiBufferOffset,
6850        rng: &mut impl rand::Rng,
6851    ) -> Range<MultiBufferOffset> {
6852        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6853        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6854        start..end
6855    }
6856
6857    #[cfg(any(test, feature = "test-support"))]
6858    fn check_invariants(&self) {
6859        let excerpts = self.excerpts.items(());
6860        let excerpt_ids = self.excerpt_ids.items(());
6861
6862        for (ix, excerpt) in excerpts.iter().enumerate() {
6863            if ix == 0 {
6864                if excerpt.locator <= Locator::min() {
6865                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6866                }
6867            } else if excerpt.locator <= excerpts[ix - 1].locator {
6868                panic!("excerpts are out-of-order: {:?}", excerpts);
6869            }
6870        }
6871
6872        for (ix, entry) in excerpt_ids.iter().enumerate() {
6873            if ix == 0 {
6874                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6875                    panic!("invalid first excerpt id {:?}", entry.id);
6876                }
6877            } else if entry.id <= excerpt_ids[ix - 1].id {
6878                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6879            }
6880        }
6881
6882        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6883            panic!(
6884                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6885                self.excerpts.summary().text,
6886                self.diff_transforms.summary().input,
6887                self.diff_transforms.items(()),
6888            );
6889        }
6890
6891        let mut prev_transform: Option<&DiffTransform> = None;
6892        for item in self.diff_transforms.iter() {
6893            if let DiffTransform::BufferContent {
6894                summary,
6895                inserted_hunk_info,
6896            } = item
6897            {
6898                if let Some(DiffTransform::BufferContent {
6899                    inserted_hunk_info: prev_inserted_hunk_info,
6900                    ..
6901                }) = prev_transform
6902                    && *inserted_hunk_info == *prev_inserted_hunk_info
6903                {
6904                    panic!(
6905                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6906                        self.diff_transforms.items(())
6907                    );
6908                }
6909                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6910                    panic!("empty buffer content transform");
6911                }
6912            }
6913            prev_transform = Some(item);
6914        }
6915    }
6916}
6917
6918impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6919where
6920    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6921    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6922{
6923    #[instrument(skip_all)]
6924    fn seek(&mut self, position: &MBD) {
6925        let position = OutputDimension(*position);
6926        self.cached_region.take();
6927        self.diff_transforms.seek(&position, Bias::Right);
6928        if self.diff_transforms.item().is_none()
6929            && self.diff_transforms.start().output_dimension == position
6930        {
6931            self.diff_transforms.prev();
6932        }
6933
6934        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6935        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6936            let overshoot = position - self.diff_transforms.start().output_dimension;
6937            excerpt_position += overshoot;
6938        }
6939
6940        self.excerpts.seek(&excerpt_position, Bias::Right);
6941        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6942            self.excerpts.prev();
6943        }
6944    }
6945
6946    fn seek_forward(&mut self, position: &MBD) {
6947        let position = OutputDimension(*position);
6948        self.cached_region.take();
6949        self.diff_transforms.seek_forward(&position, Bias::Right);
6950        if self.diff_transforms.item().is_none()
6951            && self.diff_transforms.start().output_dimension == position
6952        {
6953            self.diff_transforms.prev();
6954        }
6955
6956        let overshoot = position - self.diff_transforms.start().output_dimension;
6957        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6958        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6959            excerpt_position += overshoot;
6960        }
6961
6962        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6963        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6964            self.excerpts.prev();
6965        }
6966    }
6967
6968    fn next_excerpt(&mut self) {
6969        self.excerpts.next();
6970        self.seek_to_start_of_current_excerpt();
6971    }
6972
6973    fn prev_excerpt(&mut self) {
6974        self.excerpts.prev();
6975        self.seek_to_start_of_current_excerpt();
6976    }
6977
6978    fn seek_to_start_of_current_excerpt(&mut self) {
6979        self.cached_region.take();
6980
6981        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6982            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6983            && self.diff_transforms.next_item().is_some()
6984        {
6985            self.diff_transforms.next();
6986        }
6987    }
6988
6989    fn next_excerpt_forwards(&mut self) {
6990        self.excerpts.next();
6991        self.seek_to_start_of_current_excerpt_forward();
6992    }
6993
6994    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6995        self.cached_region.take();
6996
6997        if self
6998            .diff_transforms
6999            .seek_forward(self.excerpts.start(), Bias::Left)
7000            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7001            && self.diff_transforms.next_item().is_some()
7002        {
7003            self.diff_transforms.next();
7004        }
7005    }
7006
7007    fn next(&mut self) {
7008        self.cached_region.take();
7009        match self
7010            .diff_transforms
7011            .end()
7012            .excerpt_dimension
7013            .cmp(&self.excerpts.end())
7014        {
7015            cmp::Ordering::Less => self.diff_transforms.next(),
7016            cmp::Ordering::Greater => self.excerpts.next(),
7017            cmp::Ordering::Equal => {
7018                self.diff_transforms.next();
7019                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7020                    || self.diff_transforms.item().is_none()
7021                {
7022                    self.excerpts.next();
7023                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7024                    self.diff_transforms.item()
7025                    && self
7026                        .excerpts
7027                        .item()
7028                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7029                {
7030                    self.excerpts.next();
7031                }
7032            }
7033        }
7034    }
7035
7036    fn prev(&mut self) {
7037        self.cached_region.take();
7038        match self
7039            .diff_transforms
7040            .start()
7041            .excerpt_dimension
7042            .cmp(self.excerpts.start())
7043        {
7044            cmp::Ordering::Less => self.excerpts.prev(),
7045            cmp::Ordering::Greater => self.diff_transforms.prev(),
7046            cmp::Ordering::Equal => {
7047                self.diff_transforms.prev();
7048                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7049                    || self.diff_transforms.item().is_none()
7050                {
7051                    self.excerpts.prev();
7052                }
7053            }
7054        }
7055    }
7056
7057    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7058        self.cached_region
7059            .get_or_init(|| self.build_region())
7060            .as_ref()
7061    }
7062
7063    fn is_at_start_of_excerpt(&mut self) -> bool {
7064        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7065            return false;
7066        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7067            return true;
7068        }
7069
7070        self.diff_transforms.prev();
7071        let prev_transform = self.diff_transforms.item();
7072        self.diff_transforms.next();
7073
7074        prev_transform.is_none_or(|next_transform| {
7075            matches!(next_transform, DiffTransform::BufferContent { .. })
7076        })
7077    }
7078
7079    fn is_at_end_of_excerpt(&self) -> bool {
7080        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7081            return false;
7082        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7083            || self.diff_transforms.item().is_none()
7084        {
7085            return true;
7086        }
7087
7088        let next_transform = self.diff_transforms.next_item();
7089        next_transform.is_none_or(|next_transform| match next_transform {
7090            DiffTransform::BufferContent { .. } => true,
7091            DiffTransform::DeletedHunk { hunk_info, .. } => self
7092                .excerpts
7093                .item()
7094                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7095        })
7096    }
7097
7098    fn main_buffer_position(&self) -> Option<BD> {
7099        let excerpt = self.excerpts.item()?;
7100        let buffer = &excerpt.buffer;
7101        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7102        let mut buffer_start = buffer_context_start;
7103        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7104        buffer_start += overshoot;
7105        Some(buffer_start)
7106    }
7107
7108    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7109        let excerpt = self.excerpts.item()?;
7110        match self.diff_transforms.item()? {
7111            DiffTransform::DeletedHunk {
7112                buffer_id,
7113                base_text_byte_range,
7114                has_trailing_newline,
7115                hunk_info,
7116                ..
7117            } => {
7118                let diff = self.diffs.get(buffer_id)?;
7119                let buffer = diff.base_text();
7120                let mut rope_cursor = buffer.as_rope().cursor(0);
7121                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7122                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7123                let mut buffer_end = buffer_start;
7124                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7125                let start = self.diff_transforms.start().output_dimension.0;
7126                let end = self.diff_transforms.end().output_dimension.0;
7127                Some(MultiBufferRegion {
7128                    buffer,
7129                    excerpt,
7130                    has_trailing_newline: *has_trailing_newline,
7131                    is_main_buffer: false,
7132                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7133                        hunk_info.hunk_secondary_status,
7134                    )),
7135                    buffer_range: buffer_start..buffer_end,
7136                    range: start..end,
7137                })
7138            }
7139            DiffTransform::BufferContent {
7140                inserted_hunk_info, ..
7141            } => {
7142                let buffer = &excerpt.buffer;
7143                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7144
7145                let mut start = self.diff_transforms.start().output_dimension.0;
7146                let mut buffer_start = buffer_context_start;
7147                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7148                    let overshoot =
7149                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7150                    start += overshoot;
7151                } else {
7152                    let overshoot =
7153                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7154                    buffer_start += overshoot;
7155                }
7156
7157                let mut end;
7158                let mut buffer_end;
7159                let has_trailing_newline;
7160                let transform_end = self.diff_transforms.end();
7161                if transform_end.excerpt_dimension < self.excerpts.end() {
7162                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7163                    end = transform_end.output_dimension.0;
7164                    buffer_end = buffer_context_start;
7165                    buffer_end += overshoot;
7166                    has_trailing_newline = false;
7167                } else {
7168                    let overshoot =
7169                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7170                    end = self.diff_transforms.start().output_dimension.0;
7171                    end += overshoot;
7172                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7173                    has_trailing_newline = excerpt.has_trailing_newline;
7174                };
7175
7176                let diff_hunk_status = inserted_hunk_info.map(|info| {
7177                    if info.is_logically_deleted {
7178                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7179                    } else {
7180                        DiffHunkStatus::added(info.hunk_secondary_status)
7181                    }
7182                });
7183
7184                Some(MultiBufferRegion {
7185                    buffer,
7186                    excerpt,
7187                    has_trailing_newline,
7188                    is_main_buffer: true,
7189                    diff_hunk_status,
7190                    buffer_range: buffer_start..buffer_end,
7191                    range: start..end,
7192                })
7193            }
7194        }
7195    }
7196
7197    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7198        let excerpt = self.excerpts.item()?;
7199        match self.diff_transforms.item()? {
7200            &DiffTransform::DeletedHunk { .. } => {
7201                let start = self.diff_transforms.start().output_dimension.0;
7202                let end = self.diff_transforms.end().output_dimension.0;
7203                Some((excerpt, start..end))
7204            }
7205            DiffTransform::BufferContent { .. } => {
7206                let mut start = self.diff_transforms.start().output_dimension.0;
7207                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7208                    let overshoot =
7209                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7210                    start += overshoot;
7211                }
7212
7213                let mut end;
7214                let transform_end = self.diff_transforms.end();
7215                if transform_end.excerpt_dimension < self.excerpts.end() {
7216                    end = transform_end.output_dimension.0;
7217                } else {
7218                    let overshoot =
7219                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7220                    end = self.diff_transforms.start().output_dimension.0;
7221                    end += overshoot;
7222                };
7223
7224                Some((excerpt, start..end))
7225            }
7226        }
7227    }
7228
7229    fn excerpt(&self) -> Option<&'a Excerpt> {
7230        self.excerpts.item()
7231    }
7232}
7233
7234impl Excerpt {
7235    fn new(
7236        path_key: PathKey,
7237        buffer: Arc<BufferSnapshot>,
7238        range: ExcerptRange<text::Anchor>,
7239        has_trailing_newline: bool,
7240    ) -> Self {
7241        Excerpt {
7242            path_key,
7243            max_buffer_row: range.context.end.to_point(&buffer).row,
7244            text_summary: buffer
7245                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7246            buffer,
7247            range,
7248            has_trailing_newline,
7249        }
7250    }
7251
7252    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7253        let content_start = self.range.context.start.to_offset(&self.buffer);
7254        let chunks_start = content_start + range.start;
7255        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7256
7257        let has_footer = self.has_trailing_newline
7258            && range.start <= self.text_summary.len
7259            && range.end > self.text_summary.len;
7260
7261        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7262
7263        ExcerptChunks {
7264            content_chunks,
7265            has_footer,
7266        }
7267    }
7268
7269    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7270        let content_start = self.range.context.start.to_offset(&self.buffer);
7271        let chunks_start = content_start + range.start;
7272        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7273        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7274        excerpt_chunks.has_footer = self.has_trailing_newline
7275            && range.start <= self.text_summary.len
7276            && range.end > self.text_summary.len;
7277    }
7278
7279    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7280        if text_anchor
7281            .cmp(&self.range.context.start, &self.buffer)
7282            .is_lt()
7283        {
7284            self.range.context.start
7285        } else if text_anchor
7286            .cmp(&self.range.context.end, &self.buffer)
7287            .is_gt()
7288        {
7289            self.range.context.end
7290        } else {
7291            text_anchor
7292        }
7293    }
7294
7295    fn contains(&self, anchor: &Anchor) -> bool {
7296        (anchor.text_anchor.buffer_id == None
7297            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7298            && self
7299                .range
7300                .context
7301                .start
7302                .cmp(&anchor.text_anchor, &self.buffer)
7303                .is_le()
7304            && self
7305                .range
7306                .context
7307                .end
7308                .cmp(&anchor.text_anchor, &self.buffer)
7309                .is_ge()
7310    }
7311
7312    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7313    fn buffer_start_offset(&self) -> BufferOffset {
7314        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7315    }
7316
7317    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7318    fn buffer_end_offset(&self) -> BufferOffset {
7319        self.buffer_start_offset() + self.text_summary.len
7320    }
7321}
7322
7323impl PartialEq for Excerpt {
7324    fn eq(&self, other: &Self) -> bool {
7325        self.buffer.remote_id() == other.buffer.remote_id()
7326            && self.range.context == other.range.context
7327    }
7328}
7329
7330impl<'a> MultiBufferExcerpt<'a> {
7331    pub fn id(&self) -> ExcerptId {
7332        self.excerpt.id
7333    }
7334
7335    pub fn buffer_id(&self) -> BufferId {
7336        self.excerpt.buffer_id
7337    }
7338
7339    pub fn start_anchor(&self) -> Anchor {
7340        Anchor::text(self.excerpt.id, self.excerpt.range.context.start)
7341    }
7342
7343    pub fn end_anchor(&self) -> Anchor {
7344        Anchor::text(self.excerpt.id, self.excerpt.range.context.end)
7345    }
7346
7347    pub fn buffer(&self) -> &'a BufferSnapshot {
7348        &self.excerpt.buffer
7349    }
7350
7351    pub fn buffer_range(&self) -> Range<BufferOffset> {
7352        self.buffer_offset
7353            ..BufferOffset(
7354                self.excerpt
7355                    .range
7356                    .context
7357                    .end
7358                    .to_offset(&self.excerpt.buffer.text),
7359            )
7360    }
7361
7362    pub fn start_offset(&self) -> MultiBufferOffset {
7363        self.offset
7364    }
7365
7366    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7367    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7368        self.map_range_to_buffer(offset..offset).start
7369    }
7370
7371    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7372    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7373        self.diff_transforms
7374            .seek(&OutputDimension(range.start), Bias::Right);
7375        let start = self.map_offset_to_buffer_internal(range.start);
7376        let end = if range.end > range.start {
7377            self.diff_transforms
7378                .seek_forward(&OutputDimension(range.end), Bias::Right);
7379            self.map_offset_to_buffer_internal(range.end)
7380        } else {
7381            start
7382        };
7383        start..end
7384    }
7385
7386    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7387        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7388        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7389            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7390        };
7391        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7392        self.buffer_offset + offset_in_excerpt
7393    }
7394
7395    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7396    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7397        self.map_range_from_buffer(buffer_offset..buffer_offset)
7398            .start
7399    }
7400
7401    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7402    pub fn map_range_from_buffer(
7403        &mut self,
7404        buffer_range: Range<BufferOffset>,
7405    ) -> Range<MultiBufferOffset> {
7406        if buffer_range.start < self.buffer_offset {
7407            log::warn!(
7408                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7409            );
7410            return self.offset..self.offset;
7411        }
7412        let overshoot = buffer_range.start - self.buffer_offset;
7413        let excerpt_offset = self.excerpt_offset + overshoot;
7414        let excerpt_seek_dim = excerpt_offset;
7415        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7416        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7417            log::warn!(
7418                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7419            );
7420            return self.offset..self.offset;
7421        }
7422        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7423        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7424
7425        let end = if buffer_range.start < buffer_range.end {
7426            let overshoot = buffer_range.end - self.buffer_offset;
7427            let excerpt_offset = self.excerpt_offset + overshoot;
7428            let excerpt_seek_dim = excerpt_offset;
7429            self.diff_transforms
7430                .seek_forward(&excerpt_seek_dim, Bias::Right);
7431            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7432            // todo(lw): Clamp end to the excerpt boundaries
7433            self.diff_transforms.start().output_dimension.0 + overshoot
7434        } else {
7435            start
7436        };
7437
7438        start..end
7439    }
7440
7441    /// Returns true if the entirety of the given range is in the buffer's excerpt
7442    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7443        range.start >= self.excerpt.buffer_start_offset()
7444            && range.end <= self.excerpt.buffer_end_offset()
7445    }
7446
7447    /// Returns true if any part of the given range is in the buffer's excerpt
7448    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7449        range.start <= self.excerpt.buffer_end_offset()
7450            && range.end >= self.excerpt.buffer_start_offset()
7451    }
7452
7453    pub fn max_buffer_row(&self) -> u32 {
7454        self.excerpt.max_buffer_row
7455    }
7456}
7457
7458impl fmt::Debug for Excerpt {
7459    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7460        f.debug_struct("Excerpt")
7461            .field("path_key", &self.path_key)
7462            .field("range", &self.range)
7463            .field("text_summary", &self.text_summary)
7464            .field("has_trailing_newline", &self.has_trailing_newline)
7465            .finish()
7466    }
7467}
7468
7469impl sum_tree::Item for Excerpt {
7470    type Summary = ExcerptSummary;
7471
7472    fn summary(&self, _cx: ()) -> Self::Summary {
7473        let mut text = self.text_summary;
7474        if self.has_trailing_newline {
7475            text += TextSummary::from("\n");
7476        }
7477        ExcerptSummary {
7478            path_key: self.path_key,
7479            max_anchor: self.range.context.end,
7480            widest_line_number: self.max_buffer_row,
7481            text: text.into(),
7482            count: 1,
7483        }
7484    }
7485}
7486
7487impl DiffTransform {
7488    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7489        match self {
7490            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7491            DiffTransform::BufferContent {
7492                inserted_hunk_info, ..
7493            } => *inserted_hunk_info,
7494        }
7495    }
7496}
7497
7498impl sum_tree::Item for DiffTransform {
7499    type Summary = DiffTransformSummary;
7500
7501    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7502        match self {
7503            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7504                input: *summary,
7505                output: *summary,
7506            },
7507            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7508                input: MBTextSummary::default(),
7509                output: summary.into(),
7510            },
7511        }
7512    }
7513}
7514
7515impl DiffTransformSummary {
7516    fn excerpt_len(&self) -> ExcerptOffset {
7517        ExcerptDimension(self.input.len)
7518    }
7519}
7520
7521impl sum_tree::ContextLessSummary for DiffTransformSummary {
7522    fn zero() -> Self {
7523        DiffTransformSummary {
7524            input: MBTextSummary::default(),
7525            output: MBTextSummary::default(),
7526        }
7527    }
7528
7529    fn add_summary(&mut self, other: &Self) {
7530        self.input += other.input;
7531        self.output += other.output;
7532    }
7533}
7534
7535impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7536    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7537        PathKey::min()
7538    }
7539
7540    fn add_summary(
7541        &mut self,
7542        summary: &'_ ExcerptSummary,
7543        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7544    ) {
7545        *self = summary.path_key.clone();
7546    }
7547}
7548
7549impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7550    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7551        MultiBufferOffset::ZERO
7552    }
7553
7554    fn add_summary(
7555        &mut self,
7556        summary: &'_ ExcerptSummary,
7557        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7558    ) {
7559        self += summary.text.len
7560    }
7561}
7562
7563impl sum_tree::ContextLessSummary for ExcerptSummary {
7564    fn zero() -> Self {
7565        Self::min()
7566    }
7567
7568    fn add_summary(&mut self, summary: &Self) {
7569        debug_assert!(
7570            summary.path_key >= self.path_key,
7571            "Path keys must be in ascending order: {:?} > {:?}",
7572            summary.path_key,
7573            self.path_key
7574        );
7575
7576        self.path_key = summary.path_key.clone();
7577        self.max_anchor = summary.max_anchor;
7578        self.text += summary.text;
7579        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7580        self.count += summary.count;
7581    }
7582}
7583
7584// todo!() should this take a lifetime?
7585enum AnchorSeekTarget {
7586    Min,
7587    Max,
7588    Text {
7589        path_key: PathKey,
7590        anchor: text::Anchor,
7591        snapshot: BufferSnapshot,
7592    },
7593}
7594
7595impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7596    fn cmp(
7597        &self,
7598        cursor_location: &ExcerptSummary,
7599        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7600    ) -> cmp::Ordering {
7601        match self {
7602            AnchorSeekTarget::Min => Ordering::Less,
7603            AnchorSeekTarget::Max => Ordering::Greater,
7604            AnchorSeekTarget::Text {
7605                path_key,
7606                anchor,
7607                snapshot,
7608            } => Ord::cmp(path_key, &cursor_location.path_key)
7609                .then_with(|| anchor.cmp(&cursor_location.max_anchor, snapshot)),
7610        }
7611    }
7612}
7613
7614impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7615    fn cmp(
7616        &self,
7617        cursor_location: &ExcerptSummary,
7618        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7619    ) -> cmp::Ordering {
7620        todo!()
7621    }
7622}
7623
7624impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7625where
7626    MBD: MultiBufferDimension + Default,
7627{
7628    fn zero(_: ()) -> Self {
7629        ExcerptDimension(MBD::default())
7630    }
7631
7632    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7633        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7634    }
7635}
7636
7637#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7638struct OutputDimension<T>(T);
7639
7640impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7641    fn eq(&self, other: &T) -> bool {
7642        self.0 == *other
7643    }
7644}
7645
7646impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7647    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7648        self.0.partial_cmp(other)
7649    }
7650}
7651
7652impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7653where
7654    T: ops::Sub<U, Output = R>,
7655{
7656    type Output = R;
7657
7658    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7659        self.0 - other.0
7660    }
7661}
7662
7663impl<R, T, U> ops::Add<U> for OutputDimension<T>
7664where
7665    T: ops::Add<U, Output = R>,
7666{
7667    type Output = OutputDimension<R>;
7668
7669    fn add(self, other: U) -> Self::Output {
7670        OutputDimension(self.0 + other)
7671    }
7672}
7673
7674impl<T, U> AddAssign<U> for OutputDimension<T>
7675where
7676    T: AddAssign<U>,
7677{
7678    fn add_assign(&mut self, other: U) {
7679        self.0 += other;
7680    }
7681}
7682
7683impl<T, U> SubAssign<U> for OutputDimension<T>
7684where
7685    T: SubAssign<U>,
7686{
7687    fn sub_assign(&mut self, other: U) {
7688        self.0 -= other;
7689    }
7690}
7691
7692#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7693struct ExcerptDimension<T>(T);
7694
7695impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7696    fn eq(&self, other: &T) -> bool {
7697        self.0 == *other
7698    }
7699}
7700
7701impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7702    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7703        self.0.partial_cmp(other)
7704    }
7705}
7706
7707impl ExcerptOffset {
7708    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7709        self.0.saturating_sub(other.0)
7710    }
7711}
7712
7713impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7714where
7715    T: ops::Sub<U, Output = R>,
7716{
7717    type Output = R;
7718
7719    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7720        self.0 - other.0
7721    }
7722}
7723
7724impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7725where
7726    T: ops::Add<U, Output = R>,
7727{
7728    type Output = ExcerptDimension<R>;
7729
7730    fn add(self, other: U) -> Self::Output {
7731        ExcerptDimension(self.0 + other)
7732    }
7733}
7734
7735impl<T, U> AddAssign<U> for ExcerptDimension<T>
7736where
7737    T: AddAssign<U>,
7738{
7739    fn add_assign(&mut self, other: U) {
7740        self.0 += other;
7741    }
7742}
7743
7744impl<T, U> SubAssign<U> for ExcerptDimension<T>
7745where
7746    T: SubAssign<U>,
7747{
7748    fn sub_assign(&mut self, other: U) {
7749        self.0 -= other;
7750    }
7751}
7752
7753impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7754    fn zero(_: ()) -> Self {
7755        MultiBufferOffset::ZERO
7756    }
7757
7758    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7759        *self += summary.output.len;
7760    }
7761}
7762
7763impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7764    for ExcerptDimension<MBD>
7765where
7766    MBD: MultiBufferDimension + Ord,
7767{
7768    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7769        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7770    }
7771}
7772
7773impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7774    for ExcerptDimension<MBD>
7775where
7776    MBD: MultiBufferDimension + Ord,
7777{
7778    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7779        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7780    }
7781}
7782
7783impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7784    for ExcerptDimension<MBD>
7785{
7786    fn zero(_: ()) -> Self {
7787        ExcerptDimension(MBD::default())
7788    }
7789
7790    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7791        self.0.add_mb_text_summary(&summary.input)
7792    }
7793}
7794
7795impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7796    for OutputDimension<MBD>
7797where
7798    MBD: MultiBufferDimension + Ord,
7799{
7800    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7801        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7802    }
7803}
7804
7805impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7806    for OutputDimension<MBD>
7807{
7808    fn zero(_: ()) -> Self {
7809        OutputDimension(MBD::default())
7810    }
7811
7812    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7813        self.0.add_mb_text_summary(&summary.output)
7814    }
7815}
7816
7817impl MultiBufferRows<'_> {
7818    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7819        self.point = Point::new(row, 0);
7820        self.cursor.seek(&self.point);
7821    }
7822}
7823
7824impl Iterator for MultiBufferRows<'_> {
7825    type Item = RowInfo;
7826
7827    fn next(&mut self) -> Option<Self::Item> {
7828        if self.is_empty && self.point.row == 0 {
7829            self.point += Point::new(1, 0);
7830            return Some(RowInfo {
7831                buffer_id: None,
7832                buffer_row: Some(0),
7833                multibuffer_row: Some(MultiBufferRow(0)),
7834                diff_status: None,
7835                expand_info: None,
7836                wrapped_buffer_row: None,
7837            });
7838        }
7839
7840        let mut region = self.cursor.region()?.clone();
7841        while self.point >= region.range.end {
7842            self.cursor.next();
7843            if let Some(next_region) = self.cursor.region() {
7844                region = next_region.clone();
7845            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7846                let multibuffer_row = MultiBufferRow(self.point.row);
7847                let last_excerpt = self
7848                    .cursor
7849                    .excerpts
7850                    .item()
7851                    .or(self.cursor.excerpts.prev_item())?;
7852                let last_row = last_excerpt
7853                    .range
7854                    .context
7855                    .end
7856                    .to_point(&last_excerpt.buffer)
7857                    .row;
7858
7859                let first_row = last_excerpt
7860                    .range
7861                    .context
7862                    .start
7863                    .to_point(&last_excerpt.buffer)
7864                    .row;
7865
7866                let expand_info = if self.is_singleton {
7867                    None
7868                } else {
7869                    let needs_expand_up = first_row == last_row
7870                        && last_row > 0
7871                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7872                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7873
7874                    if needs_expand_up && needs_expand_down {
7875                        Some(ExpandExcerptDirection::UpAndDown)
7876                    } else if needs_expand_up {
7877                        Some(ExpandExcerptDirection::Up)
7878                    } else if needs_expand_down {
7879                        Some(ExpandExcerptDirection::Down)
7880                    } else {
7881                        None
7882                    }
7883                    .map(|direction| ExpandInfo {
7884                        direction,
7885                        excerpt_id: last_excerpt.id,
7886                    })
7887                };
7888                self.point += Point::new(1, 0);
7889                return Some(RowInfo {
7890                    buffer_id: Some(last_excerpt.buffer_id),
7891                    buffer_row: Some(last_row),
7892                    multibuffer_row: Some(multibuffer_row),
7893                    diff_status: None,
7894                    wrapped_buffer_row: None,
7895                    expand_info,
7896                });
7897            } else {
7898                return None;
7899            };
7900        }
7901
7902        let overshoot = self.point - region.range.start;
7903        let buffer_point = region.buffer_range.start + overshoot;
7904        let expand_info = if self.is_singleton {
7905            None
7906        } else {
7907            let needs_expand_up = self.point.row == region.range.start.row
7908                && self.cursor.is_at_start_of_excerpt()
7909                && buffer_point.row > 0;
7910            let needs_expand_down = (region.excerpt.has_trailing_newline
7911                && self.point.row + 1 == region.range.end.row
7912                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7913                && self.cursor.is_at_end_of_excerpt()
7914                && buffer_point.row < region.buffer.max_point().row;
7915
7916            if needs_expand_up && needs_expand_down {
7917                Some(ExpandExcerptDirection::UpAndDown)
7918            } else if needs_expand_up {
7919                Some(ExpandExcerptDirection::Up)
7920            } else if needs_expand_down {
7921                Some(ExpandExcerptDirection::Down)
7922            } else {
7923                None
7924            }
7925            .map(|direction| ExpandInfo {
7926                direction,
7927                excerpt_id: region.excerpt.id,
7928            })
7929        };
7930
7931        let result = Some(RowInfo {
7932            buffer_id: Some(region.buffer.remote_id()),
7933            buffer_row: Some(buffer_point.row),
7934            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7935            diff_status: region
7936                .diff_hunk_status
7937                .filter(|_| self.point < region.range.end),
7938            expand_info,
7939            wrapped_buffer_row: None,
7940        });
7941        self.point += Point::new(1, 0);
7942        result
7943    }
7944}
7945
7946impl<'a> MultiBufferChunks<'a> {
7947    pub fn offset(&self) -> MultiBufferOffset {
7948        self.range.start
7949    }
7950
7951    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7952        self.diff_transforms.seek(&range.end, Bias::Right);
7953        let mut excerpt_end = self.diff_transforms.start().1;
7954        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7955            let overshoot = range.end - self.diff_transforms.start().0;
7956            excerpt_end += overshoot;
7957        }
7958
7959        self.diff_transforms.seek(&range.start, Bias::Right);
7960        let mut excerpt_start = self.diff_transforms.start().1;
7961        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7962            let overshoot = range.start - self.diff_transforms.start().0;
7963            excerpt_start += overshoot;
7964        }
7965
7966        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7967        self.buffer_chunk.take();
7968        self.range = range;
7969    }
7970
7971    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7972        self.excerpt_offset_range = new_range.clone();
7973        self.excerpts.seek(&new_range.start, Bias::Right);
7974        if let Some(excerpt) = self.excerpts.item() {
7975            let excerpt_start = *self.excerpts.start();
7976            if let Some(excerpt_chunks) = self
7977                .excerpt_chunks
7978                .as_mut()
7979                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7980            {
7981                excerpt.seek_chunks(
7982                    excerpt_chunks,
7983                    (self.excerpt_offset_range.start - excerpt_start)
7984                        ..(self.excerpt_offset_range.end - excerpt_start),
7985                );
7986            } else {
7987                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7988                    (self.excerpt_offset_range.start - excerpt_start)
7989                        ..(self.excerpt_offset_range.end - excerpt_start),
7990                    self.language_aware,
7991                ));
7992            }
7993        } else {
7994            self.excerpt_chunks = None;
7995        }
7996    }
7997
7998    #[ztracing::instrument(skip_all)]
7999    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8000        loop {
8001            if self.excerpt_offset_range.is_empty() {
8002                return None;
8003            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8004                self.excerpt_offset_range.start += chunk.text.len();
8005                return Some(chunk);
8006            } else {
8007                self.excerpts.next();
8008                let excerpt = self.excerpts.item()?;
8009                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8010                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8011                    self.language_aware,
8012                ));
8013            }
8014        }
8015    }
8016}
8017
8018impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8019    type Item = &'a str;
8020
8021    fn next(&mut self) -> Option<Self::Item> {
8022        let mut region = self.cursor.region()?;
8023        if self.offset == region.range.start {
8024            self.cursor.prev();
8025            region = self.cursor.region()?;
8026            let start_overshoot = self.start.saturating_sub(region.range.start);
8027            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8028                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8029            ));
8030        }
8031
8032        if self.offset == region.range.end && region.has_trailing_newline {
8033            self.offset -= 1;
8034            Some("\n")
8035        } else {
8036            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8037            self.offset -= chunk.len();
8038            Some(chunk)
8039        }
8040    }
8041}
8042
8043impl<'a> Iterator for MultiBufferChunks<'a> {
8044    type Item = Chunk<'a>;
8045
8046    #[ztracing::instrument(skip_all)]
8047    fn next(&mut self) -> Option<Chunk<'a>> {
8048        if self.range.start >= self.range.end {
8049            return None;
8050        }
8051        if self.range.start == self.diff_transforms.end().0 {
8052            self.diff_transforms.next();
8053        }
8054
8055        let diff_transform_start = self.diff_transforms.start().0;
8056        let diff_transform_end = self.diff_transforms.end().0;
8057        debug_assert!(
8058            self.range.start < diff_transform_end,
8059            "{:?} < {:?} of ({1:?}..{2:?})",
8060            self.range.start,
8061            diff_transform_end,
8062            diff_transform_start
8063        );
8064
8065        let diff_transform = self.diff_transforms.item()?;
8066        match diff_transform {
8067            DiffTransform::BufferContent { .. } => {
8068                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8069                    chunk
8070                } else {
8071                    let chunk = self.next_excerpt_chunk().unwrap();
8072                    self.buffer_chunk.insert(chunk)
8073                };
8074
8075                let chunk_end = self.range.start + chunk.text.len();
8076                let diff_transform_end = diff_transform_end.min(self.range.end);
8077
8078                if diff_transform_end < chunk_end {
8079                    let split_idx = diff_transform_end - self.range.start;
8080                    let (before, after) = chunk.text.split_at(split_idx);
8081                    self.range.start = diff_transform_end;
8082                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8083                    let chars = chunk.chars & mask;
8084                    let tabs = chunk.tabs & mask;
8085                    let newlines = chunk.newlines & mask;
8086
8087                    chunk.text = after;
8088                    chunk.chars = chunk.chars >> split_idx;
8089                    chunk.tabs = chunk.tabs >> split_idx;
8090                    chunk.newlines = chunk.newlines >> split_idx;
8091
8092                    Some(Chunk {
8093                        text: before,
8094                        chars,
8095                        tabs,
8096                        newlines,
8097                        ..chunk.clone()
8098                    })
8099                } else {
8100                    self.range.start = chunk_end;
8101                    self.buffer_chunk.take()
8102                }
8103            }
8104            DiffTransform::DeletedHunk {
8105                buffer_id,
8106                base_text_byte_range,
8107                has_trailing_newline,
8108                ..
8109            } => {
8110                let base_text_start =
8111                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8112                let base_text_end =
8113                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8114                let base_text_end = base_text_end.min(base_text_byte_range.end);
8115
8116                let mut chunks = if let Some((_, mut chunks)) = self
8117                    .diff_base_chunks
8118                    .take()
8119                    .filter(|(id, _)| id == buffer_id)
8120                {
8121                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8122                    {
8123                        chunks.seek(base_text_start..base_text_end);
8124                    }
8125                    chunks
8126                } else {
8127                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8128                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8129                };
8130
8131                let chunk = if let Some(chunk) = chunks.next() {
8132                    self.range.start += chunk.text.len();
8133                    self.diff_base_chunks = Some((*buffer_id, chunks));
8134                    chunk
8135                } else {
8136                    debug_assert!(has_trailing_newline);
8137                    self.range.start += "\n".len();
8138                    Chunk {
8139                        text: "\n",
8140                        chars: 1u128,
8141                        newlines: 1u128,
8142                        ..Default::default()
8143                    }
8144                };
8145                Some(chunk)
8146            }
8147        }
8148    }
8149}
8150
8151impl MultiBufferBytes<'_> {
8152    fn consume(&mut self, len: usize) {
8153        self.range.start += len;
8154        self.chunk = &self.chunk[len..];
8155
8156        if !self.range.is_empty() && self.chunk.is_empty() {
8157            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8158                self.chunk = chunk;
8159            } else if self.has_trailing_newline {
8160                self.has_trailing_newline = false;
8161                self.chunk = b"\n";
8162            } else {
8163                self.cursor.next();
8164                if let Some(region) = self.cursor.region() {
8165                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8166                        region.buffer_range.start
8167                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8168                                .min(region.buffer_range.end),
8169                    );
8170                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8171                    self.excerpt_bytes = Some(excerpt_bytes);
8172                    self.has_trailing_newline =
8173                        region.has_trailing_newline && self.range.end >= region.range.end;
8174                    if self.chunk.is_empty() && self.has_trailing_newline {
8175                        self.has_trailing_newline = false;
8176                        self.chunk = b"\n";
8177                    }
8178                }
8179            }
8180        }
8181    }
8182}
8183
8184impl<'a> Iterator for MultiBufferBytes<'a> {
8185    type Item = &'a [u8];
8186
8187    fn next(&mut self) -> Option<Self::Item> {
8188        let chunk = self.chunk;
8189        if chunk.is_empty() {
8190            None
8191        } else {
8192            self.consume(chunk.len());
8193            Some(chunk)
8194        }
8195    }
8196}
8197
8198impl io::Read for MultiBufferBytes<'_> {
8199    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8200        let len = cmp::min(buf.len(), self.chunk.len());
8201        buf[..len].copy_from_slice(&self.chunk[..len]);
8202        if len > 0 {
8203            self.consume(len);
8204        }
8205        Ok(len)
8206    }
8207}
8208
8209impl io::Read for ReversedMultiBufferBytes<'_> {
8210    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8211        let len = cmp::min(buf.len(), self.chunk.len());
8212        buf[..len].copy_from_slice(&self.chunk[..len]);
8213        buf[..len].reverse();
8214        if len > 0 {
8215            self.range.end -= len;
8216            self.chunk = &self.chunk[..self.chunk.len() - len];
8217            if !self.range.is_empty()
8218                && self.chunk.is_empty()
8219                && let Some(chunk) = self.chunks.next()
8220            {
8221                self.chunk = chunk.as_bytes();
8222            }
8223        }
8224        Ok(len)
8225    }
8226}
8227
8228impl<'a> Iterator for ExcerptChunks<'a> {
8229    type Item = Chunk<'a>;
8230
8231    fn next(&mut self) -> Option<Self::Item> {
8232        if let Some(chunk) = self.content_chunks.next() {
8233            return Some(chunk);
8234        }
8235
8236        if self.has_footer {
8237            let text = "\n";
8238            let chars = 0b1;
8239            let newlines = 0b1;
8240            self.has_footer = false;
8241            return Some(Chunk {
8242                text,
8243                chars,
8244                newlines,
8245                ..Default::default()
8246            });
8247        }
8248
8249        None
8250    }
8251}
8252
8253impl ToOffset for Point {
8254    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8255        snapshot.point_to_offset(*self)
8256    }
8257    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8258        snapshot.point_to_offset_utf16(*self)
8259    }
8260}
8261
8262impl ToOffset for MultiBufferOffset {
8263    #[track_caller]
8264    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8265        assert!(
8266            *self <= snapshot.len(),
8267            "offset {} is greater than the snapshot.len() {}",
8268            self.0,
8269            snapshot.len().0,
8270        );
8271        *self
8272    }
8273    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8274        snapshot.offset_to_offset_utf16(*self)
8275    }
8276}
8277
8278impl ToOffset for MultiBufferOffsetUtf16 {
8279    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8280        snapshot.offset_utf16_to_offset(*self)
8281    }
8282
8283    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8284        *self
8285    }
8286}
8287
8288impl ToOffset for PointUtf16 {
8289    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8290        snapshot.point_utf16_to_offset(*self)
8291    }
8292    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8293        snapshot.point_utf16_to_offset_utf16(*self)
8294    }
8295}
8296
8297impl ToPoint for MultiBufferOffset {
8298    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8299        snapshot.offset_to_point(*self)
8300    }
8301    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8302        snapshot.offset_to_point_utf16(*self)
8303    }
8304}
8305
8306impl ToPoint for Point {
8307    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8308        *self
8309    }
8310    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8311        snapshot.point_to_point_utf16(*self)
8312    }
8313}
8314
8315impl ToPoint for PointUtf16 {
8316    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8317        snapshot.point_utf16_to_point(*self)
8318    }
8319    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8320        *self
8321    }
8322}
8323
8324#[cfg(debug_assertions)]
8325pub mod debug {
8326    use super::*;
8327
8328    pub trait ToMultiBufferDebugRanges {
8329        fn to_multi_buffer_debug_ranges(
8330            &self,
8331            snapshot: &MultiBufferSnapshot,
8332        ) -> Vec<Range<MultiBufferOffset>>;
8333    }
8334
8335    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8336        fn to_multi_buffer_debug_ranges(
8337            &self,
8338            snapshot: &MultiBufferSnapshot,
8339        ) -> Vec<Range<MultiBufferOffset>> {
8340            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8341        }
8342    }
8343
8344    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8345        fn to_multi_buffer_debug_ranges(
8346            &self,
8347            snapshot: &MultiBufferSnapshot,
8348        ) -> Vec<Range<MultiBufferOffset>> {
8349            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8350                .to_multi_buffer_debug_ranges(snapshot)
8351        }
8352    }
8353
8354    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8355        fn to_multi_buffer_debug_ranges(
8356            &self,
8357            snapshot: &MultiBufferSnapshot,
8358        ) -> Vec<Range<MultiBufferOffset>> {
8359            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8360        }
8361    }
8362
8363    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8364        fn to_multi_buffer_debug_ranges(
8365            &self,
8366            snapshot: &MultiBufferSnapshot,
8367        ) -> Vec<Range<MultiBufferOffset>> {
8368            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8369        }
8370    }
8371
8372    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8373        fn to_multi_buffer_debug_ranges(
8374            &self,
8375            snapshot: &MultiBufferSnapshot,
8376        ) -> Vec<Range<MultiBufferOffset>> {
8377            self.iter()
8378                .map(|item| {
8379                    let offset = item.to_offset(snapshot);
8380                    offset..offset
8381                })
8382                .collect()
8383        }
8384    }
8385
8386    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8387        fn to_multi_buffer_debug_ranges(
8388            &self,
8389            snapshot: &MultiBufferSnapshot,
8390        ) -> Vec<Range<MultiBufferOffset>> {
8391            self.iter()
8392                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8393                .collect()
8394        }
8395    }
8396}