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