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, ControlFlow, 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        let buffer_id = buffer.read(cx).remote_id();
2287        cx.emit(match event {
2288            BufferEvent::Edited => Event::Edited {
2289                edited_buffer: Some(buffer),
2290            },
2291            BufferEvent::DirtyChanged => Event::DirtyChanged,
2292            BufferEvent::Saved => Event::Saved,
2293            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2294            BufferEvent::Reloaded => Event::Reloaded,
2295            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer_id),
2296            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2297            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2298            BufferEvent::CapabilityChanged => {
2299                self.capability = buffer.read(cx).capability();
2300                return;
2301            }
2302            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2303        });
2304    }
2305
2306    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2307        let diff = diff.read(cx);
2308        let buffer_id = diff.buffer_id;
2309        let diff = diff.snapshot(cx);
2310        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2311    }
2312
2313    fn buffer_diff_changed(
2314        &mut self,
2315        diff: Entity<BufferDiff>,
2316        range: Range<text::Anchor>,
2317        cx: &mut Context<Self>,
2318    ) {
2319        self.sync_mut(cx);
2320
2321        let diff = diff.read(cx);
2322        let buffer_id = diff.buffer_id;
2323        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2324            return;
2325        };
2326        self.buffer_changed_since_sync.replace(true);
2327
2328        let buffer = buffer_state.buffer.read(cx);
2329        let diff_change_range = range.to_offset(buffer);
2330
2331        let new_diff = diff.snapshot(cx);
2332        let mut snapshot = self.snapshot.get_mut();
2333        let base_text_changed = snapshot
2334            .diffs
2335            .get(&buffer_id)
2336            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2337
2338        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2339
2340        let mut excerpt_edits = Vec::new();
2341        for locator in &buffer_state.excerpts {
2342            let mut cursor = snapshot
2343                .excerpts
2344                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2345            cursor.seek_forward(&Some(locator), Bias::Left);
2346            if let Some(excerpt) = cursor.item()
2347                && excerpt.locator == *locator
2348            {
2349                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2350                if diff_change_range.end < excerpt_buffer_range.start
2351                    || diff_change_range.start > excerpt_buffer_range.end
2352                {
2353                    continue;
2354                }
2355                let excerpt_start = cursor.start().1;
2356                let excerpt_len = excerpt.text_summary.len;
2357                let diff_change_start_in_excerpt = diff_change_range
2358                    .start
2359                    .saturating_sub(excerpt_buffer_range.start);
2360                let diff_change_end_in_excerpt = diff_change_range
2361                    .end
2362                    .saturating_sub(excerpt_buffer_range.start);
2363                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2364                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2365                excerpt_edits.push(Edit {
2366                    old: edit_start..edit_end,
2367                    new: edit_start..edit_end,
2368                });
2369            }
2370        }
2371
2372        let edits = Self::sync_diff_transforms(
2373            &mut snapshot,
2374            excerpt_edits,
2375            DiffChangeKind::DiffUpdated {
2376                base_changed: base_text_changed,
2377            },
2378            self.filter_mode,
2379        );
2380        if !edits.is_empty() {
2381            self.subscriptions.publish(edits);
2382        }
2383        cx.emit(Event::Edited {
2384            edited_buffer: None,
2385        });
2386    }
2387
2388    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2389        self.buffers
2390            .values()
2391            .map(|state| state.buffer.clone())
2392            .collect()
2393    }
2394
2395    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2396        self.buffers.keys().copied().collect()
2397    }
2398
2399    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2400        self.buffers
2401            .get(&buffer_id)
2402            .map(|state| state.buffer.clone())
2403    }
2404
2405    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2406        self.point_to_buffer_offset(point, cx)
2407            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2408    }
2409
2410    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2411        let buffer_id = self
2412            .snapshot
2413            .borrow()
2414            .excerpts
2415            .first()
2416            .map(|excerpt| excerpt.buffer.remote_id());
2417        buffer_id
2418            .and_then(|buffer_id| self.buffer(buffer_id))
2419            .map(|buffer| {
2420                let buffer = buffer.read(cx);
2421                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2422            })
2423            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2424    }
2425
2426    pub fn language_settings_at<'a, T: ToOffset>(
2427        &'a self,
2428        point: T,
2429        cx: &'a App,
2430    ) -> Cow<'a, LanguageSettings> {
2431        let mut language = None;
2432        let mut file = None;
2433        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2434            let buffer = buffer.read(cx);
2435            language = buffer.language_at(offset);
2436            file = buffer.file();
2437        }
2438        language_settings(language.map(|l| l.name()), file, cx)
2439    }
2440
2441    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2442        self.buffers.values().for_each(|state| f(&state.buffer))
2443    }
2444
2445    pub fn explicit_title(&self) -> Option<&str> {
2446        self.title.as_deref()
2447    }
2448
2449    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2450        if let Some(title) = self.title.as_ref() {
2451            return title.into();
2452        }
2453
2454        if let Some(buffer) = self.as_singleton() {
2455            let buffer = buffer.read(cx);
2456
2457            if let Some(file) = buffer.file() {
2458                return file.file_name(cx).into();
2459            }
2460
2461            if let Some(title) = self.buffer_content_title(buffer) {
2462                return title;
2463            }
2464        };
2465
2466        "untitled".into()
2467    }
2468
2469    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2470        let mut is_leading_whitespace = true;
2471        let mut count = 0;
2472        let mut prev_was_space = false;
2473        let mut title = String::new();
2474
2475        for ch in buffer.snapshot().chars() {
2476            if is_leading_whitespace && ch.is_whitespace() {
2477                continue;
2478            }
2479
2480            is_leading_whitespace = false;
2481
2482            if ch == '\n' || count >= 40 {
2483                break;
2484            }
2485
2486            if ch.is_whitespace() {
2487                if !prev_was_space {
2488                    title.push(' ');
2489                    count += 1;
2490                    prev_was_space = true;
2491                }
2492            } else {
2493                title.push(ch);
2494                count += 1;
2495                prev_was_space = false;
2496            }
2497        }
2498
2499        let title = title.trim_end().to_string();
2500
2501        if title.is_empty() {
2502            return None;
2503        }
2504
2505        Some(title.into())
2506    }
2507
2508    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2509        self.title = Some(title);
2510        cx.notify();
2511    }
2512
2513    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2514    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2515        for buffer_state in self.buffers.values() {
2516            buffer_state
2517                .buffer
2518                .update(cx, |buffer, _cx| buffer.refresh_preview());
2519        }
2520    }
2521
2522    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2523    pub fn preserve_preview(&self, cx: &App) -> bool {
2524        self.buffers
2525            .values()
2526            .all(|state| state.buffer.read(cx).preserve_preview())
2527    }
2528
2529    #[cfg(any(test, feature = "test-support"))]
2530    pub fn is_parsing(&self, cx: &App) -> bool {
2531        self.as_singleton().unwrap().read(cx).is_parsing()
2532    }
2533
2534    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2535        let buffer_id = diff.read(cx).buffer_id;
2536        self.buffer_diff_changed(
2537            diff.clone(),
2538            text::Anchor::min_max_range_for_buffer(buffer_id),
2539            cx,
2540        );
2541        self.diffs
2542            .insert(buffer_id, DiffState::new(diff.clone(), cx));
2543
2544        if let Some(follower) = &self.follower {
2545            follower.update(cx, |follower, cx| {
2546                follower.add_diff(diff, cx);
2547            })
2548        }
2549    }
2550
2551    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2552        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2553    }
2554
2555    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2556        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2557    }
2558
2559    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2560        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2561    }
2562
2563    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2564        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2565        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2566    }
2567
2568    pub fn all_diff_hunks_expanded(&self) -> bool {
2569        self.snapshot.borrow().all_diff_hunks_expanded
2570    }
2571
2572    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2573        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2574        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2575    }
2576
2577    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2578        self.read(cx)
2579            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2580            .nth(1)
2581            .is_some()
2582    }
2583
2584    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2585        let snapshot = self.read(cx);
2586        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2587        let offset_range = range.to_offset(&snapshot);
2588        cursor.seek(&offset_range.start, Bias::Left);
2589        while let Some(item) = cursor.item() {
2590            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2591                break;
2592            }
2593            if item.hunk_info().is_some() {
2594                return true;
2595            }
2596            cursor.next();
2597        }
2598        false
2599    }
2600
2601    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2602        let snapshot = self.read(cx);
2603        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2604        for range in ranges {
2605            let range = range.to_point(&snapshot);
2606            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2607            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2608            let start = start.saturating_sub_usize(1);
2609            let end = snapshot.len().min(end + 1usize);
2610            cursor.seek(&start, Bias::Right);
2611            while let Some(item) = cursor.item() {
2612                if *cursor.start() >= end {
2613                    break;
2614                }
2615                if item.hunk_info().is_some() {
2616                    return true;
2617                }
2618                cursor.next();
2619            }
2620        }
2621        false
2622    }
2623
2624    pub fn expand_or_collapse_diff_hunks_inner(
2625        &mut self,
2626        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2627        expand: bool,
2628        cx: &mut Context<Self>,
2629    ) {
2630        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2631            return;
2632        }
2633        self.sync_mut(cx);
2634        let mut snapshot = self.snapshot.get_mut();
2635        let mut excerpt_edits = Vec::new();
2636        let mut last_hunk_row = None;
2637        for (range, end_excerpt_id) in ranges {
2638            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2639                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2640                    continue;
2641                }
2642                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2643                    continue;
2644                }
2645                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2646                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2647                let start = snapshot.excerpt_offset_for_anchor(&start);
2648                let end = snapshot.excerpt_offset_for_anchor(&end);
2649                last_hunk_row = Some(diff_hunk.row_range.start);
2650                excerpt_edits.push(text::Edit {
2651                    old: start..end,
2652                    new: start..end,
2653                });
2654            }
2655        }
2656
2657        let edits = Self::sync_diff_transforms(
2658            &mut snapshot,
2659            excerpt_edits,
2660            DiffChangeKind::ExpandOrCollapseHunks { expand },
2661            self.filter_mode,
2662        );
2663        if !edits.is_empty() {
2664            self.subscriptions.publish(edits);
2665        }
2666        cx.emit(Event::DiffHunksToggled);
2667        cx.emit(Event::Edited {
2668            edited_buffer: None,
2669        });
2670    }
2671
2672    pub fn expand_or_collapse_diff_hunks(
2673        &mut self,
2674        ranges: Vec<Range<Anchor>>,
2675        expand: bool,
2676        cx: &mut Context<Self>,
2677    ) {
2678        let snapshot = self.snapshot.borrow().clone();
2679        let ranges = ranges.iter().map(move |range| {
2680            let end_excerpt_id = range.end.excerpt_id;
2681            let range = range.to_point(&snapshot);
2682            let mut peek_end = range.end;
2683            if range.end.row < snapshot.max_row().0 {
2684                peek_end = Point::new(range.end.row + 1, 0);
2685            };
2686            (range.start..peek_end, end_excerpt_id)
2687        });
2688        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2689    }
2690
2691    pub fn resize_excerpt(
2692        &mut self,
2693        id: ExcerptId,
2694        range: Range<text::Anchor>,
2695        cx: &mut Context<Self>,
2696    ) {
2697        self.sync_mut(cx);
2698
2699        let mut snapshot = self.snapshot.get_mut();
2700        let locator = snapshot.excerpt_locator_for_id(id);
2701        let mut new_excerpts = SumTree::default();
2702        let mut cursor = snapshot
2703            .excerpts
2704            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2705        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2706
2707        let prefix = cursor.slice(&Some(locator), Bias::Left);
2708        new_excerpts.append(prefix, ());
2709
2710        let mut excerpt = cursor.item().unwrap().clone();
2711        let old_text_len = excerpt.text_summary.len;
2712
2713        excerpt.range.context.start = range.start;
2714        excerpt.range.context.end = range.end;
2715        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2716
2717        excerpt.text_summary = excerpt
2718            .buffer
2719            .text_summary_for_range(excerpt.range.context.clone());
2720
2721        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2722        let old_start_offset = cursor.start().1;
2723        let new_text_len = excerpt.text_summary.len;
2724        let edit = Edit {
2725            old: old_start_offset..old_start_offset + old_text_len,
2726            new: new_start_offset..new_start_offset + new_text_len,
2727        };
2728
2729        if let Some(last_edit) = edits.last_mut() {
2730            if last_edit.old.end == edit.old.start {
2731                last_edit.old.end = edit.old.end;
2732                last_edit.new.end = edit.new.end;
2733            } else {
2734                edits.push(edit);
2735            }
2736        } else {
2737            edits.push(edit);
2738        }
2739
2740        new_excerpts.push(excerpt, ());
2741
2742        cursor.next();
2743
2744        new_excerpts.append(cursor.suffix(), ());
2745
2746        drop(cursor);
2747        snapshot.excerpts = new_excerpts;
2748
2749        if let Some(follower) = &self.follower {
2750            follower.update(cx, |follower, cx| follower.resize_excerpt(id, range, cx));
2751        }
2752
2753        let edits = Self::sync_diff_transforms(
2754            &mut snapshot,
2755            edits,
2756            DiffChangeKind::BufferEdited,
2757            self.filter_mode,
2758        );
2759        if !edits.is_empty() {
2760            self.subscriptions.publish(edits);
2761        }
2762        cx.emit(Event::Edited {
2763            edited_buffer: None,
2764        });
2765        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2766        cx.notify();
2767    }
2768
2769    pub fn expand_excerpts(
2770        &mut self,
2771        ids: impl IntoIterator<Item = ExcerptId>,
2772        line_count: u32,
2773        direction: ExpandExcerptDirection,
2774        cx: &mut Context<Self>,
2775    ) {
2776        if line_count == 0 {
2777            return;
2778        }
2779        self.sync_mut(cx);
2780        if !self.excerpts_by_path.is_empty() {
2781            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2782            return;
2783        }
2784        let mut snapshot = self.snapshot.get_mut();
2785
2786        let ids = ids.into_iter().collect::<Vec<_>>();
2787        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2788        let mut new_excerpts = SumTree::default();
2789        let mut cursor = snapshot
2790            .excerpts
2791            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2792        let mut excerpt_edits = Vec::<Edit<ExcerptOffset>>::new();
2793
2794        for locator in &locators {
2795            let prefix = cursor.slice(&Some(locator), Bias::Left);
2796            new_excerpts.append(prefix, ());
2797
2798            let mut excerpt = cursor.item().unwrap().clone();
2799            let old_text_len = excerpt.text_summary.len;
2800
2801            let up_line_count = if direction.should_expand_up() {
2802                line_count
2803            } else {
2804                0
2805            };
2806
2807            let start_row = excerpt
2808                .range
2809                .context
2810                .start
2811                .to_point(&excerpt.buffer)
2812                .row
2813                .saturating_sub(up_line_count);
2814            let start_point = Point::new(start_row, 0);
2815            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2816
2817            let down_line_count = if direction.should_expand_down() {
2818                line_count
2819            } else {
2820                0
2821            };
2822
2823            let mut end_point = excerpt.buffer.clip_point(
2824                excerpt.range.context.end.to_point(&excerpt.buffer)
2825                    + Point::new(down_line_count, 0),
2826                Bias::Left,
2827            );
2828            end_point.column = excerpt.buffer.line_len(end_point.row);
2829            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2830            excerpt.max_buffer_row = end_point.row;
2831
2832            excerpt.text_summary = excerpt
2833                .buffer
2834                .text_summary_for_range(excerpt.range.context.clone());
2835
2836            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2837            let old_start_offset = cursor.start().1;
2838            let new_text_len = excerpt.text_summary.len;
2839            let edit = Edit {
2840                old: old_start_offset..old_start_offset + old_text_len,
2841                new: new_start_offset..new_start_offset + new_text_len,
2842            };
2843
2844            if let Some(last_edit) = excerpt_edits.last_mut() {
2845                if last_edit.old.end == edit.old.start {
2846                    last_edit.old.end = edit.old.end;
2847                    last_edit.new.end = edit.new.end;
2848                } else {
2849                    excerpt_edits.push(edit);
2850                }
2851            } else {
2852                excerpt_edits.push(edit);
2853            }
2854
2855            new_excerpts.push(excerpt, ());
2856
2857            cursor.next();
2858        }
2859
2860        new_excerpts.append(cursor.suffix(), ());
2861
2862        drop(cursor);
2863        snapshot.excerpts = new_excerpts.clone();
2864
2865        let edits = Self::sync_diff_transforms(
2866            &mut snapshot,
2867            excerpt_edits.clone(),
2868            DiffChangeKind::BufferEdited,
2869            self.filter_mode,
2870        );
2871        if !edits.is_empty() {
2872            self.subscriptions.publish(edits);
2873        }
2874        if let Some(follower) = &self.follower {
2875            follower.update(cx, |follower, cx| {
2876                follower.expand_excerpts(ids.clone(), line_count, direction, cx);
2877            })
2878        }
2879        cx.emit(Event::Edited {
2880            edited_buffer: None,
2881        });
2882        cx.emit(Event::ExcerptsExpanded { ids });
2883        cx.notify();
2884    }
2885
2886    fn sync(&self, cx: &App) {
2887        let changed = self.buffer_changed_since_sync.replace(false);
2888        if !changed {
2889            return;
2890        }
2891        let edits = Self::sync_from_buffer_changes(
2892            &mut self.snapshot.borrow_mut(),
2893            &self.buffers,
2894            &self.diffs,
2895            self.filter_mode,
2896            cx,
2897        );
2898        if !edits.is_empty() {
2899            self.subscriptions.publish(edits);
2900        }
2901    }
2902
2903    fn sync_mut(&mut self, cx: &App) {
2904        let changed = self.buffer_changed_since_sync.replace(false);
2905        if !changed {
2906            return;
2907        }
2908        let edits = Self::sync_from_buffer_changes(
2909            self.snapshot.get_mut(),
2910            &self.buffers,
2911            &self.diffs,
2912            self.filter_mode,
2913            cx,
2914        );
2915
2916        if !edits.is_empty() {
2917            self.subscriptions.publish(edits);
2918        }
2919    }
2920
2921    fn sync_from_buffer_changes(
2922        snapshot: &mut MultiBufferSnapshot,
2923        buffers: &HashMap<BufferId, BufferState>,
2924        diffs: &HashMap<BufferId, DiffState>,
2925        filter_mode: Option<MultiBufferFilterMode>,
2926        cx: &App,
2927    ) -> Vec<Edit<MultiBufferOffset>> {
2928        let MultiBufferSnapshot {
2929            excerpts,
2930            diffs: buffer_diff,
2931            diff_transforms: _,
2932            non_text_state_update_count,
2933            edit_count,
2934            is_dirty,
2935            has_deleted_file,
2936            has_conflict,
2937            singleton: _,
2938            excerpt_ids: _,
2939            replaced_excerpts: _,
2940            trailing_excerpt_update_count: _,
2941            all_diff_hunks_expanded: _,
2942            show_headers: _,
2943        } = snapshot;
2944        *is_dirty = false;
2945        *has_deleted_file = false;
2946        *has_conflict = false;
2947
2948        let mut excerpts_to_edit = Vec::new();
2949        let mut non_text_state_updated = false;
2950        let mut edited = false;
2951        for buffer_state in buffers.values() {
2952            let buffer = buffer_state.buffer.read(cx);
2953            let version = buffer.version();
2954            let non_text_state_update_count = buffer.non_text_state_update_count();
2955
2956            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2957            let buffer_non_text_state_updated =
2958                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2959            if buffer_edited || buffer_non_text_state_updated {
2960                *buffer_state.last_version.borrow_mut() = version;
2961                buffer_state
2962                    .last_non_text_state_update_count
2963                    .set(non_text_state_update_count);
2964                excerpts_to_edit.extend(
2965                    buffer_state
2966                        .excerpts
2967                        .iter()
2968                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2969                );
2970            }
2971
2972            edited |= buffer_edited;
2973            non_text_state_updated |= buffer_non_text_state_updated;
2974            *is_dirty |= buffer.is_dirty();
2975            *has_deleted_file |= buffer
2976                .file()
2977                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2978            *has_conflict |= buffer.has_conflict();
2979        }
2980        if edited {
2981            *edit_count += 1;
2982        }
2983        if non_text_state_updated {
2984            *non_text_state_update_count += 1;
2985        }
2986
2987        for (id, diff) in diffs.iter() {
2988            if buffer_diff.get(id).is_none() {
2989                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2990            }
2991        }
2992
2993        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2994
2995        let mut edits = Vec::new();
2996        let mut new_excerpts = SumTree::default();
2997        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2998
2999        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3000            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3001            let old_excerpt = cursor.item().unwrap();
3002            let buffer = buffer.read(cx);
3003            let buffer_id = buffer.remote_id();
3004
3005            let mut new_excerpt;
3006            if buffer_edited {
3007                edits.extend(
3008                    buffer
3009                        .edits_since_in_range::<usize>(
3010                            old_excerpt.buffer.version(),
3011                            old_excerpt.range.context.clone(),
3012                        )
3013                        .map(|edit| {
3014                            let excerpt_old_start = cursor.start().1;
3015                            let excerpt_new_start =
3016                                ExcerptDimension(new_excerpts.summary().text.len);
3017                            let old_start = excerpt_old_start + edit.old.start;
3018                            let old_end = excerpt_old_start + edit.old.end;
3019                            let new_start = excerpt_new_start + edit.new.start;
3020                            let new_end = excerpt_new_start + edit.new.end;
3021                            Edit {
3022                                old: old_start..old_end,
3023                                new: new_start..new_end,
3024                            }
3025                        }),
3026                );
3027
3028                new_excerpt = Excerpt::new(
3029                    old_excerpt.id,
3030                    locator.clone(),
3031                    buffer_id,
3032                    buffer.snapshot(),
3033                    old_excerpt.range.clone(),
3034                    old_excerpt.has_trailing_newline,
3035                );
3036            } else {
3037                new_excerpt = old_excerpt.clone();
3038                new_excerpt.buffer = buffer.snapshot();
3039            }
3040
3041            new_excerpts.push(new_excerpt, ());
3042            cursor.next();
3043        }
3044        new_excerpts.append(cursor.suffix(), ());
3045
3046        drop(cursor);
3047        *excerpts = new_excerpts;
3048        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited, filter_mode)
3049    }
3050
3051    fn sync_diff_transforms(
3052        snapshot: &mut MultiBufferSnapshot,
3053        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3054        change_kind: DiffChangeKind,
3055        filter_mode: Option<MultiBufferFilterMode>,
3056    ) -> Vec<Edit<MultiBufferOffset>> {
3057        if excerpt_edits.is_empty() {
3058            return vec![];
3059        }
3060
3061        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3062        let mut old_diff_transforms = snapshot
3063            .diff_transforms
3064            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3065        let mut new_diff_transforms = SumTree::default();
3066        let mut old_expanded_hunks = HashSet::default();
3067        let mut output_edits = Vec::new();
3068        let mut output_delta = 0_isize;
3069        let mut at_transform_boundary = true;
3070        let mut end_of_current_insert = None;
3071
3072        let mut excerpt_edits: VecDeque<_> = excerpt_edits.into_iter().collect();
3073        while let Some(edit) = excerpt_edits.pop_front() {
3074            excerpts.seek_forward(&edit.new.start, Bias::Right);
3075            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3076                excerpts.prev();
3077            }
3078
3079            // Keep any transforms that are before the edit.
3080            if at_transform_boundary {
3081                at_transform_boundary = false;
3082                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3083                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3084                if let Some(transform) = old_diff_transforms.item()
3085                    && old_diff_transforms.end().0 == edit.old.start
3086                    && old_diff_transforms.start().0 < edit.old.start
3087                {
3088                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3089                    old_diff_transforms.next();
3090                }
3091            }
3092
3093            // Compute the start of the edit in output coordinates.
3094            let edit_start_overshoot = if let Some(DiffTransform::FilteredInsertedHunk { .. }) =
3095                old_diff_transforms.item()
3096            {
3097                0
3098            } else {
3099                edit.old.start - old_diff_transforms.start().0
3100            };
3101            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3102            let edit_new_start =
3103                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3104
3105            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3106                &edit,
3107                &mut excerpts,
3108                &mut old_diff_transforms,
3109                &mut new_diff_transforms,
3110                &mut end_of_current_insert,
3111                &mut old_expanded_hunks,
3112                snapshot,
3113                change_kind,
3114                filter_mode,
3115            );
3116
3117            // When the added range of a hunk is edited, the end anchor of the hunk may be moved later
3118            // in response by hunks_intersecting_range to keep it at a row boundary. In KeepDeletions
3119            // mode, we need to make sure that the whole added range is still filtered out in this situation.
3120            // We do that by adding an additional edit that covers the rest of the hunk added range.
3121            if let Some(current_inserted_hunk) = &end_of_current_insert
3122                && current_inserted_hunk.is_filtered
3123                // No additional edit needed if we've already covered the whole added range.
3124                && current_inserted_hunk.insertion_end_offset > edit.new.end
3125                // No additional edit needed if this edit just touched the start of the hunk
3126                // (this also prevents pushing the deleted region for the hunk twice).
3127                && edit.new.end > current_inserted_hunk.hunk_excerpt_start
3128                // No additional edit needed if there is a subsequent edit that intersects
3129                // the same hunk (the last such edit will take care of it).
3130                && excerpt_edits.front().is_none_or(|next_edit| {
3131                    next_edit.new.start >= current_inserted_hunk.insertion_end_offset
3132                })
3133            {
3134                let overshoot = current_inserted_hunk.insertion_end_offset - edit.new.end;
3135                let additional_edit = Edit {
3136                    old: edit.old.end..edit.old.end + overshoot,
3137                    new: edit.new.end..current_inserted_hunk.insertion_end_offset,
3138                };
3139                excerpt_edits.push_front(additional_edit);
3140            }
3141
3142            // Compute the end of the edit in output coordinates.
3143            let edit_old_end_overshoot = if let Some(DiffTransform::FilteredInsertedHunk {
3144                ..
3145            }) = old_diff_transforms.item()
3146            {
3147                ExcerptDimension(MultiBufferOffset(0))
3148            } else {
3149                ExcerptDimension(MultiBufferOffset(
3150                    edit.old.end - old_diff_transforms.start().0,
3151                ))
3152            };
3153            let edit_new_end_overshoot = if let Some(current_inserted_hunk) = &end_of_current_insert
3154                && current_inserted_hunk.is_filtered
3155            {
3156                let insertion_end_offset = current_inserted_hunk.insertion_end_offset;
3157                let excerpt_len = new_diff_transforms.summary().excerpt_len();
3158                let base = insertion_end_offset.max(excerpt_len);
3159                edit.new.end.saturating_sub(base)
3160            } else {
3161                edit.new.end - new_diff_transforms.summary().excerpt_len()
3162            };
3163            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.0;
3164            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3165            let output_edit = Edit {
3166                old: edit_old_start..edit_old_end,
3167                new: edit_new_start..edit_new_end,
3168            };
3169
3170            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3171            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3172            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3173                output_edits.push(output_edit);
3174            }
3175
3176            // If this is the last edit that intersects the current diff transform,
3177            // then recreate the content up to the end of this transform, to prepare
3178            // for reusing additional slices of the old transforms.
3179            if excerpt_edits
3180                .front()
3181                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3182            {
3183                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3184                    && match old_diff_transforms.item() {
3185                        Some(
3186                            DiffTransform::InsertedHunk { hunk_info, .. }
3187                            | DiffTransform::FilteredInsertedHunk { hunk_info, .. },
3188                        ) => excerpts.item().is_some_and(|excerpt| {
3189                            hunk_info.hunk_start_anchor.is_valid(&excerpt.buffer)
3190                        }),
3191                        _ => true,
3192                    };
3193
3194                let mut excerpt_offset = edit.new.end;
3195                if !keep_next_old_transform {
3196                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3197                    old_diff_transforms.next();
3198                }
3199
3200                old_expanded_hunks.clear();
3201                Self::push_buffer_content_transform(
3202                    snapshot,
3203                    &mut new_diff_transforms,
3204                    excerpt_offset,
3205                    end_of_current_insert.as_ref(),
3206                );
3207                at_transform_boundary = true;
3208            }
3209        }
3210
3211        // Keep any transforms that are after the last edit.
3212        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3213
3214        // Ensure there's always at least one buffer content transform.
3215        if new_diff_transforms.is_empty() {
3216            new_diff_transforms.push(
3217                DiffTransform::Unmodified {
3218                    summary: Default::default(),
3219                },
3220                (),
3221            );
3222        }
3223
3224        drop(old_diff_transforms);
3225        drop(excerpts);
3226        snapshot.diff_transforms = new_diff_transforms;
3227        snapshot.edit_count += 1;
3228
3229        #[cfg(any(test, feature = "test-support"))]
3230        snapshot.check_invariants();
3231        output_edits
3232    }
3233
3234    fn recompute_diff_transforms_for_edit(
3235        edit: &Edit<ExcerptOffset>,
3236        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3237        old_diff_transforms: &mut Cursor<
3238            DiffTransform,
3239            Dimensions<ExcerptOffset, MultiBufferOffset>,
3240        >,
3241        new_diff_transforms: &mut SumTree<DiffTransform>,
3242        end_of_current_insert: &mut Option<CurrentInsertedHunk>,
3243        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3244        snapshot: &MultiBufferSnapshot,
3245        change_kind: DiffChangeKind,
3246        filter_mode: Option<MultiBufferFilterMode>,
3247    ) -> bool {
3248        log::trace!(
3249            "recomputing diff transform for edit {:?} => {:?}",
3250            edit.old.start..edit.old.end,
3251            edit.new.start..edit.new.end
3252        );
3253
3254        // Record which hunks were previously expanded.
3255        while let Some(item) = old_diff_transforms.item() {
3256            if let Some(hunk_info) = item.hunk_info() {
3257                log::trace!(
3258                    "previously expanded hunk at {:?}",
3259                    old_diff_transforms.start()
3260                );
3261                old_expanded_hunks.insert(hunk_info);
3262            }
3263            if old_diff_transforms.end().0 > edit.old.end {
3264                break;
3265            }
3266            old_diff_transforms.next();
3267        }
3268
3269        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3270        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3271        if old_expanded_hunks.is_empty()
3272            && change_kind == DiffChangeKind::BufferEdited
3273            && !all_diff_hunks_expanded
3274        {
3275            return false;
3276        }
3277
3278        // Visit each excerpt that intersects the edit.
3279        let mut did_expand_hunks = false;
3280        while let Some(excerpt) = excerpts.item() {
3281            // Recompute the expanded hunks in the portion of the excerpt that
3282            // intersects the edit.
3283            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3284                let buffer = &excerpt.buffer;
3285                let excerpt_start = *excerpts.start();
3286                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3287                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3288                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3289                let edit_buffer_start =
3290                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3291                let edit_buffer_end =
3292                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3293                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3294                let edit_anchor_range =
3295                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3296
3297                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3298                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3299                        continue;
3300                    }
3301
3302                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3303                    if hunk_buffer_range.start < excerpt_buffer_start {
3304                        log::trace!("skipping hunk that starts before excerpt");
3305                        continue;
3306                    }
3307
3308                    let hunk_info = DiffTransformHunkInfo {
3309                        excerpt_id: excerpt.id,
3310                        hunk_start_anchor: hunk.buffer_range.start,
3311                        hunk_secondary_status: hunk.secondary_status,
3312                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3313                    };
3314
3315                    let hunk_excerpt_start = excerpt_start
3316                        + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3317                    let hunk_excerpt_end = excerpt_end
3318                        .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3319
3320                    Self::push_buffer_content_transform(
3321                        snapshot,
3322                        new_diff_transforms,
3323                        hunk_excerpt_start,
3324                        end_of_current_insert.as_ref(),
3325                    );
3326
3327                    // For every existing hunk, determine if it was previously expanded
3328                    // and if it should currently be expanded.
3329                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3330                    let should_expand_hunk = match &change_kind {
3331                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3332                            was_previously_expanded || all_diff_hunks_expanded
3333                        }
3334                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3335                            let intersects = hunk_buffer_range.is_empty()
3336                                || hunk_buffer_range.end > edit_buffer_start;
3337                            if *expand {
3338                                intersects || was_previously_expanded || all_diff_hunks_expanded
3339                            } else {
3340                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3341                            }
3342                        }
3343                        _ => was_previously_expanded || all_diff_hunks_expanded,
3344                    };
3345
3346                    if should_expand_hunk {
3347                        did_expand_hunks = true;
3348                        log::trace!(
3349                            "expanding hunk {:?}, excerpt:{:?}",
3350                            hunk_excerpt_start..hunk_excerpt_end,
3351                            excerpt.id
3352                        );
3353
3354                        if !hunk.diff_base_byte_range.is_empty()
3355                            && hunk_buffer_range.start >= edit_buffer_start
3356                            && hunk_buffer_range.start <= excerpt_buffer_end
3357                            && filter_mode != Some(MultiBufferFilterMode::KeepInsertions)
3358                        {
3359                            let base_text = diff.base_text();
3360                            let mut text_cursor =
3361                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3362                            let mut base_text_summary =
3363                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3364
3365                            let mut has_trailing_newline = false;
3366                            if base_text_summary.last_line_chars > 0 {
3367                                base_text_summary += TextSummary::newline();
3368                                has_trailing_newline = true;
3369                            }
3370
3371                            new_diff_transforms.push(
3372                                DiffTransform::DeletedHunk {
3373                                    summary: base_text_summary,
3374                                    buffer_id: excerpt.buffer_id,
3375                                    hunk_info: hunk_info.clone(),
3376                                    has_trailing_newline,
3377                                },
3378                                (),
3379                            );
3380                        }
3381
3382                        if !hunk_buffer_range.is_empty() {
3383                            let is_filtered =
3384                                filter_mode == Some(MultiBufferFilterMode::KeepDeletions);
3385                            let insertion_end_offset = hunk_excerpt_end.min(excerpt_end);
3386                            *end_of_current_insert = Some(CurrentInsertedHunk {
3387                                hunk_excerpt_start,
3388                                insertion_end_offset,
3389                                hunk_info,
3390                                is_filtered,
3391                            });
3392                        }
3393                    }
3394                }
3395            }
3396
3397            if excerpts.end() <= edit.new.end {
3398                excerpts.next();
3399            } else {
3400                break;
3401            }
3402        }
3403
3404        did_expand_hunks || !old_expanded_hunks.is_empty()
3405    }
3406
3407    fn append_diff_transforms(
3408        new_transforms: &mut SumTree<DiffTransform>,
3409        subtree: SumTree<DiffTransform>,
3410    ) {
3411        if let Some(transform) = subtree.first()
3412            && Self::extend_last_buffer_content_transform(new_transforms, transform)
3413        {
3414            let mut cursor = subtree.cursor::<()>(());
3415            cursor.next();
3416            cursor.next();
3417            new_transforms.append(cursor.suffix(), ());
3418            return;
3419        }
3420        new_transforms.append(subtree, ());
3421    }
3422
3423    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3424        if Self::extend_last_buffer_content_transform(new_transforms, &transform) {
3425            return;
3426        }
3427        new_transforms.push(transform, ());
3428    }
3429
3430    fn push_buffer_content_transform(
3431        old_snapshot: &MultiBufferSnapshot,
3432        new_transforms: &mut SumTree<DiffTransform>,
3433        end_offset: ExcerptOffset,
3434        current_inserted_hunk: Option<&CurrentInsertedHunk>,
3435    ) {
3436        if let Some(current_inserted_hunk) = current_inserted_hunk {
3437            let start_offset = new_transforms.summary().excerpt_len();
3438            let end_offset = current_inserted_hunk.insertion_end_offset.min(end_offset);
3439            if end_offset > start_offset {
3440                let summary_to_add = old_snapshot
3441                    .text_summary_for_excerpt_offset_range::<MBTextSummary>(
3442                        start_offset..end_offset,
3443                    );
3444
3445                let transform = if current_inserted_hunk.is_filtered {
3446                    DiffTransform::FilteredInsertedHunk {
3447                        summary: summary_to_add,
3448                        hunk_info: current_inserted_hunk.hunk_info.clone(),
3449                    }
3450                } else {
3451                    DiffTransform::InsertedHunk {
3452                        summary: summary_to_add,
3453                        hunk_info: current_inserted_hunk.hunk_info.clone(),
3454                    }
3455                };
3456                if !Self::extend_last_buffer_content_transform(new_transforms, &transform) {
3457                    new_transforms.push(transform, ())
3458                }
3459            }
3460        }
3461
3462        let start_offset = new_transforms.summary().excerpt_len();
3463        if end_offset > start_offset {
3464            let summary_to_add = old_snapshot
3465                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3466
3467            let transform = DiffTransform::Unmodified {
3468                summary: summary_to_add,
3469            };
3470            if !Self::extend_last_buffer_content_transform(new_transforms, &transform) {
3471                new_transforms.push(transform, ())
3472            }
3473        }
3474    }
3475
3476    fn extend_last_buffer_content_transform(
3477        new_transforms: &mut SumTree<DiffTransform>,
3478        transform: &DiffTransform,
3479    ) -> bool {
3480        let mut did_extend = false;
3481        new_transforms.update_last(
3482            |last_transform| {
3483                did_extend = last_transform.merge_with(&transform);
3484            },
3485            (),
3486        );
3487        did_extend
3488    }
3489}
3490
3491impl DiffTransform {
3492    /// Ergonomic wrapper for [`DiffTransform::merged_with`] that applies the
3493    /// merging in-place. Returns `true` if merging was possible.
3494    #[must_use = "check whether merging actually succeeded"]
3495    fn merge_with(&mut self, other: &Self) -> bool {
3496        match self.to_owned().merged_with(other) {
3497            Some(merged) => {
3498                *self = merged;
3499                true
3500            }
3501            None => false,
3502        }
3503    }
3504
3505    /// Attempt to merge `self` with `other`, and return the merged transform.
3506    ///
3507    /// This will succeed if all of the following are true:
3508    /// - both transforms are the same variant
3509    /// - neither transform is [`DiffTransform::DeletedHunk`]
3510    /// - if both transform are either [`DiffTransform::InsertedHunk`] or
3511    ///   [`DiffTransform::FilteredInsertedHunk`], then their
3512    ///   `hunk_info.hunk_start_anchor`s match
3513    #[must_use = "check whether merging actually succeeded"]
3514    #[rustfmt::skip]
3515    fn merged_with(self, other: &Self) -> Option<Self> {
3516        match (self, other) {
3517            (
3518                DiffTransform::Unmodified { mut summary },
3519                DiffTransform::Unmodified { summary: other_summary },
3520            ) => {
3521                summary += *other_summary;
3522                Some(DiffTransform::Unmodified { summary })
3523            }
3524            (
3525                DiffTransform::FilteredInsertedHunk { mut summary, hunk_info },
3526                DiffTransform::FilteredInsertedHunk {
3527                    hunk_info: other_hunk_info,
3528                    summary: other_summary,
3529                },
3530            ) => {
3531                if hunk_info.hunk_start_anchor == other_hunk_info.hunk_start_anchor {
3532                    summary += *other_summary;
3533                    Some(DiffTransform::FilteredInsertedHunk { summary, hunk_info })
3534                } else {
3535                    None
3536                }
3537            }
3538            (
3539                DiffTransform::InsertedHunk { mut summary, hunk_info },
3540                DiffTransform::InsertedHunk {
3541                    hunk_info: other_hunk_info,
3542                    summary: other_summary,
3543                },
3544            ) => {
3545                if hunk_info.hunk_start_anchor == other_hunk_info.hunk_start_anchor {
3546                    summary += *other_summary;
3547                    Some(DiffTransform::InsertedHunk { summary, hunk_info })
3548                } else {
3549                    None
3550                }
3551            }
3552            _ => return None,
3553        }
3554    }
3555}
3556
3557fn build_excerpt_ranges(
3558    ranges: impl IntoIterator<Item = Range<Point>>,
3559    context_line_count: u32,
3560    buffer_snapshot: &BufferSnapshot,
3561) -> Vec<ExcerptRange<Point>> {
3562    ranges
3563        .into_iter()
3564        .map(|range| {
3565            let start_row = range.start.row.saturating_sub(context_line_count);
3566            let start = Point::new(start_row, 0);
3567            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3568            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3569            ExcerptRange {
3570                context: start..end,
3571                primary: range,
3572            }
3573        })
3574        .collect()
3575}
3576
3577#[cfg(any(test, feature = "test-support"))]
3578impl MultiBuffer {
3579    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3580        let buffer = cx.new(|cx| Buffer::local(text, cx));
3581        cx.new(|cx| Self::singleton(buffer, cx))
3582    }
3583
3584    pub fn build_multi<const COUNT: usize>(
3585        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3586        cx: &mut gpui::App,
3587    ) -> Entity<Self> {
3588        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3589        for (text, ranges) in excerpts {
3590            let buffer = cx.new(|cx| Buffer::local(text, cx));
3591            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3592            multi.update(cx, |multi, cx| {
3593                multi.push_excerpts(buffer, excerpt_ranges, cx)
3594            });
3595        }
3596
3597        multi
3598    }
3599
3600    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3601        cx.new(|cx| Self::singleton(buffer, cx))
3602    }
3603
3604    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3605        cx.new(|cx| {
3606            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3607            let mutation_count = rng.random_range(1..=5);
3608            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3609            multibuffer
3610        })
3611    }
3612
3613    pub fn randomly_edit(
3614        &mut self,
3615        rng: &mut impl rand::Rng,
3616        edit_count: usize,
3617        cx: &mut Context<Self>,
3618    ) {
3619        use util::RandomCharIter;
3620
3621        let snapshot = self.read(cx);
3622        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3623        let mut last_end = None;
3624        for _ in 0..edit_count {
3625            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3626                break;
3627            }
3628
3629            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3630            let end =
3631                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3632            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3633            last_end = Some(end);
3634
3635            let mut range = start..end;
3636            if rng.random_bool(0.2) {
3637                mem::swap(&mut range.start, &mut range.end);
3638            }
3639
3640            let new_text_len = rng.random_range(0..10);
3641            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3642
3643            edits.push((range, new_text.into()));
3644        }
3645        log::info!("mutating multi-buffer with {:?}", edits);
3646        drop(snapshot);
3647
3648        self.edit(edits, None, cx);
3649    }
3650
3651    pub fn randomly_edit_excerpts(
3652        &mut self,
3653        rng: &mut impl rand::Rng,
3654        mutation_count: usize,
3655        cx: &mut Context<Self>,
3656    ) {
3657        use rand::prelude::*;
3658        use std::env;
3659        use util::RandomCharIter;
3660
3661        let max_excerpts = env::var("MAX_EXCERPTS")
3662            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3663            .unwrap_or(5);
3664
3665        let mut buffers = Vec::new();
3666        for _ in 0..mutation_count {
3667            if rng.random_bool(0.05) {
3668                log::info!("Clearing multi-buffer");
3669                self.clear(cx);
3670                continue;
3671            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3672                let ids = self.excerpt_ids();
3673                let mut excerpts = HashSet::default();
3674                for _ in 0..rng.random_range(0..ids.len()) {
3675                    excerpts.extend(ids.choose(rng).copied());
3676                }
3677
3678                let line_count = rng.random_range(0..5);
3679
3680                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3681
3682                self.expand_excerpts(
3683                    excerpts.iter().cloned(),
3684                    line_count,
3685                    ExpandExcerptDirection::UpAndDown,
3686                    cx,
3687                );
3688                continue;
3689            }
3690
3691            let excerpt_ids = self.excerpt_ids();
3692            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3693                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3694                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3695                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3696                    let buffer = buffers.last().unwrap().read(cx);
3697                    log::info!(
3698                        "Creating new buffer {} with text: {:?}",
3699                        buffer.remote_id(),
3700                        buffer.text()
3701                    );
3702                    buffers.last().unwrap().clone()
3703                } else {
3704                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3705                };
3706
3707                let buffer = buffer_handle.read(cx);
3708                let buffer_text = buffer.text();
3709                let ranges = (0..rng.random_range(0..5))
3710                    .map(|_| {
3711                        let end_ix =
3712                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3713                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3714                        ExcerptRange::new(start_ix..end_ix)
3715                    })
3716                    .collect::<Vec<_>>();
3717                log::info!(
3718                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3719                    buffer_handle.read(cx).remote_id(),
3720                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3721                    ranges
3722                        .iter()
3723                        .map(|r| &buffer_text[r.context.clone()])
3724                        .collect::<Vec<_>>()
3725                );
3726
3727                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3728                log::info!("Inserted with ids: {:?}", excerpt_id);
3729            } else {
3730                let remove_count = rng.random_range(1..=excerpt_ids.len());
3731                let mut excerpts_to_remove = excerpt_ids
3732                    .choose_multiple(rng, remove_count)
3733                    .cloned()
3734                    .collect::<Vec<_>>();
3735                let snapshot = self.snapshot.borrow();
3736                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3737                drop(snapshot);
3738                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3739                self.remove_excerpts(excerpts_to_remove, cx);
3740            }
3741        }
3742    }
3743
3744    pub fn randomly_mutate(
3745        &mut self,
3746        rng: &mut impl rand::Rng,
3747        mutation_count: usize,
3748        cx: &mut Context<Self>,
3749    ) {
3750        use rand::prelude::*;
3751
3752        if rng.random_bool(0.7) || self.singleton {
3753            let buffer = self
3754                .buffers
3755                .values()
3756                .choose(rng)
3757                .map(|state| state.buffer.clone());
3758
3759            if let Some(buffer) = buffer {
3760                buffer.update(cx, |buffer, cx| {
3761                    if rng.random() {
3762                        buffer.randomly_edit(rng, mutation_count, cx);
3763                    } else {
3764                        buffer.randomly_undo_redo(rng, cx);
3765                    }
3766                });
3767            } else {
3768                self.randomly_edit(rng, mutation_count, cx);
3769            }
3770        } else {
3771            self.randomly_edit_excerpts(rng, mutation_count, cx);
3772        }
3773
3774        self.check_invariants(cx);
3775    }
3776
3777    fn check_invariants(&self, cx: &App) {
3778        self.read(cx).check_invariants();
3779    }
3780}
3781
3782impl EventEmitter<Event> for MultiBuffer {}
3783
3784impl MultiBufferSnapshot {
3785    pub fn text(&self) -> String {
3786        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3787            .map(|chunk| chunk.text)
3788            .collect()
3789    }
3790
3791    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3792        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3793            .flat_map(|c| c.chars().rev())
3794    }
3795
3796    fn reversed_chunks_in_range(
3797        &self,
3798        range: Range<MultiBufferOffset>,
3799    ) -> ReversedMultiBufferChunks<'_> {
3800        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3801        cursor.seek(&range.end);
3802        let current_chunks = cursor.region().as_ref().map(|region| {
3803            let start_overshoot = range.start.saturating_sub(region.range.start);
3804            let end_overshoot = range.end - region.range.start;
3805            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3806            let start = region.buffer_range.start + start_overshoot;
3807            region.buffer.reversed_chunks_in_range(start..end)
3808        });
3809        ReversedMultiBufferChunks {
3810            cursor,
3811            current_chunks,
3812            start: range.start,
3813            offset: range.end,
3814        }
3815    }
3816
3817    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3818        let offset = position.to_offset(self);
3819        self.text_for_range(offset..self.len())
3820            .flat_map(|chunk| chunk.chars())
3821    }
3822
3823    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3824        self.chunks(range, false).map(|chunk| chunk.text)
3825    }
3826
3827    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3828        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3829            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3830    }
3831
3832    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3833    where
3834        T: ToOffset,
3835    {
3836        let position = position.to_offset(self);
3837        position == self.clip_offset(position, Bias::Left)
3838            && self
3839                .bytes_in_range(position..self.len())
3840                .flatten()
3841                .copied()
3842                .take(needle.len())
3843                .eq(needle.bytes())
3844    }
3845
3846    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3847        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3848    }
3849
3850    pub fn diff_hunks_in_range<T: ToPoint>(
3851        &self,
3852        range: Range<T>,
3853    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3854        let query_range = range.start.to_point(self)..range.end.to_point(self);
3855        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3856            let diff = self.diffs.get(&buffer.remote_id())?;
3857            let buffer_start = buffer.anchor_before(buffer_range.start);
3858            let buffer_end = buffer.anchor_after(buffer_range.end);
3859            Some(
3860                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3861                    .filter_map(|hunk| {
3862                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3863                            return None;
3864                        }
3865                        Some((hunk.range.clone(), hunk))
3866                    }),
3867            )
3868        })
3869        .filter_map(move |(range, hunk, excerpt)| {
3870            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3871            {
3872                return None;
3873            }
3874            let end_row = if range.end.column == 0 {
3875                range.end.row
3876            } else {
3877                range.end.row + 1
3878            };
3879
3880            let word_diffs = (!hunk.base_word_diffs.is_empty()
3881                || !hunk.buffer_word_diffs.is_empty())
3882            .then(|| {
3883                let hunk_start_offset =
3884                    Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_offset(self);
3885
3886                hunk.base_word_diffs
3887                    .iter()
3888                    .map(|diff| hunk_start_offset + diff.start..hunk_start_offset + diff.end)
3889                    .chain(
3890                        hunk.buffer_word_diffs
3891                            .into_iter()
3892                            .map(|diff| Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)),
3893                    )
3894                    .collect()
3895            })
3896            .unwrap_or_default();
3897
3898            Some(MultiBufferDiffHunk {
3899                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3900                buffer_id: excerpt.buffer_id,
3901                excerpt_id: excerpt.id,
3902                buffer_range: hunk.buffer_range.clone(),
3903                word_diffs,
3904                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3905                    ..BufferOffset(hunk.diff_base_byte_range.end),
3906                secondary_status: hunk.secondary_status,
3907            })
3908        })
3909    }
3910
3911    fn excerpts_for_range<T: ToOffset>(
3912        &self,
3913        range: Range<T>,
3914    ) -> impl Iterator<Item = &Excerpt> + '_ {
3915        let range = range.start.to_offset(self)..range.end.to_offset(self);
3916        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3917        cursor.seek(&range.start);
3918        std::iter::from_fn(move || {
3919            let region = cursor.region()?;
3920            if region.range.start > range.end
3921                || region.range.start == range.end && region.range.start > range.start
3922            {
3923                return None;
3924            }
3925            cursor.next_excerpt();
3926            Some(region.excerpt)
3927        })
3928    }
3929
3930    pub fn excerpt_ids_for_range<T: ToOffset>(
3931        &self,
3932        range: Range<T>,
3933    ) -> impl Iterator<Item = ExcerptId> + '_ {
3934        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3935    }
3936
3937    pub fn buffer_ids_for_range<T: ToOffset>(
3938        &self,
3939        range: Range<T>,
3940    ) -> impl Iterator<Item = BufferId> + '_ {
3941        self.excerpts_for_range(range)
3942            .map(|excerpt| excerpt.buffer_id)
3943    }
3944
3945    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3946        &self,
3947        ranges: impl Iterator<Item = Range<T>>,
3948    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3949        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3950    }
3951
3952    pub fn range_to_buffer_ranges<T: ToOffset>(
3953        &self,
3954        range: Range<T>,
3955    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3956        let start = range.start.to_offset(self);
3957        let end = range.end.to_offset(self);
3958
3959        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3960        cursor.seek(&start);
3961
3962        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
3963        while let Some(region) = cursor.region() {
3964            if region.range.start > end {
3965                break;
3966            }
3967            if region.is_main_buffer {
3968                let start_overshoot = start.saturating_sub(region.range.start);
3969                let end_overshoot = end.saturating_sub(region.range.start);
3970                let start = region
3971                    .buffer_range
3972                    .end
3973                    .min(region.buffer_range.start + start_overshoot);
3974                let end = region
3975                    .buffer_range
3976                    .end
3977                    .min(region.buffer_range.start + end_overshoot);
3978                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3979                    *excerpt_id == region.excerpt.id && prev_range.end == start
3980                }) {
3981                    prev.1.end = end;
3982                } else {
3983                    result.push((region.buffer, start..end, region.excerpt.id));
3984                }
3985            }
3986            cursor.next();
3987        }
3988        result
3989    }
3990
3991    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3992        &self,
3993        range: Range<T>,
3994    ) -> impl Iterator<
3995        Item = (
3996            &BufferSnapshot,
3997            Range<BufferOffset>,
3998            ExcerptId,
3999            Option<Anchor>,
4000        ),
4001    > + '_ {
4002        let start = range.start.to_offset(self);
4003        let end = range.end.to_offset(self);
4004
4005        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4006        cursor.seek(&start);
4007
4008        std::iter::from_fn(move || {
4009            let region = cursor.region()?;
4010            if region.range.start > end {
4011                return None;
4012            }
4013            let start_overshoot = start.saturating_sub(region.range.start);
4014            let end_overshoot = end.saturating_sub(region.range.start);
4015            let start = region
4016                .buffer_range
4017                .end
4018                .min(region.buffer_range.start + start_overshoot);
4019            let end = region
4020                .buffer_range
4021                .end
4022                .min(region.buffer_range.start + end_overshoot);
4023
4024            let region_excerpt_id = region.excerpt.id;
4025            let deleted_hunk_anchor = if region.is_main_buffer {
4026                None
4027            } else {
4028                Some(self.anchor_before(region.range.start))
4029            };
4030            let result = (
4031                region.buffer,
4032                start..end,
4033                region_excerpt_id,
4034                deleted_hunk_anchor,
4035            );
4036            cursor.next();
4037            Some(result)
4038        })
4039    }
4040
4041    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4042    /// coordinates.
4043    ///
4044    /// The given callback will be called for every excerpt intersecting the given range. It will
4045    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4046    /// The callback should return an iterator of metadata items from that buffer, each paired
4047    /// with a buffer range.
4048    ///
4049    /// The returned iterator yields each of these metadata items, paired with its range in
4050    /// multi-buffer coordinates.
4051    fn lift_buffer_metadata<'a, MBD, M, I>(
4052        &'a self,
4053        query_range: Range<MBD>,
4054        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4055    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4056    where
4057        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4058        MBD: MultiBufferDimension
4059            + Ord
4060            + Sub<Output = MBD::TextDimension>
4061            + ops::Add<MBD::TextDimension, Output = MBD>
4062            + ops::AddAssign<MBD::TextDimension>,
4063        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4064            + ops::Add<Output = MBD::TextDimension>
4065            + AddAssign<MBD::TextDimension>
4066            + Ord,
4067    {
4068        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4069        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4070
4071        // Find the excerpt and buffer offset where the given range ends.
4072        cursor.seek(&query_range.end);
4073        let mut range_end = None;
4074        while let Some(region) = cursor.region() {
4075            if region.is_main_buffer {
4076                let mut buffer_end = region.buffer_range.start;
4077                let overshoot = if query_range.end > region.range.start {
4078                    query_range.end - region.range.start
4079                } else {
4080                    <MBD::TextDimension>::default()
4081                };
4082                buffer_end = buffer_end + overshoot;
4083                range_end = Some((region.excerpt.id, buffer_end));
4084                break;
4085            }
4086            cursor.next();
4087        }
4088
4089        cursor.seek(&query_range.start);
4090
4091        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4092            && region.range.start > MBD::default()
4093        {
4094            cursor.prev()
4095        }
4096
4097        iter::from_fn(move || {
4098            loop {
4099                let excerpt = cursor.excerpt()?;
4100
4101                // If we have already retrieved metadata for this excerpt, continue to use it.
4102                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4103                    .as_mut()
4104                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4105                {
4106                    Some(metadata)
4107                }
4108                // Otherwise, compute the intersection of the input range with the excerpt's range,
4109                // and retrieve the metadata for the resulting range.
4110                else {
4111                    let region = cursor.region()?;
4112                    let mut buffer_start;
4113                    if region.is_main_buffer {
4114                        buffer_start = region.buffer_range.start;
4115                        if query_range.start > region.range.start {
4116                            let overshoot = query_range.start - region.range.start;
4117                            buffer_start = buffer_start + overshoot;
4118                        }
4119                        buffer_start = buffer_start.min(region.buffer_range.end);
4120                    } else {
4121                        buffer_start = cursor.main_buffer_position()?;
4122                    };
4123                    let mut buffer_end = excerpt
4124                        .range
4125                        .context
4126                        .end
4127                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4128                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4129                        && excerpt.id == end_excerpt_id
4130                    {
4131                        buffer_end = buffer_end.min(end_buffer_offset);
4132                    }
4133
4134                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4135                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4136                    })
4137                };
4138
4139                // Visit each metadata item.
4140                if let Some((metadata_buffer_range, metadata)) =
4141                    metadata_iter.and_then(Iterator::next)
4142                {
4143                    // Find the multibuffer regions that contain the start and end of
4144                    // the metadata item's range.
4145                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4146                        while let Some(region) = cursor.region() {
4147                            if region.is_main_buffer
4148                                && (region.buffer_range.end >= metadata_buffer_range.start
4149                                    || cursor.is_at_end_of_excerpt())
4150                            {
4151                                break;
4152                            }
4153                            cursor.next();
4154                        }
4155                    }
4156                    let start_region = cursor.region()?;
4157                    while let Some(region) = cursor.region() {
4158                        if region.is_main_buffer
4159                            && (region.buffer_range.end > metadata_buffer_range.end
4160                                || cursor.is_at_end_of_excerpt())
4161                        {
4162                            break;
4163                        }
4164                        cursor.next();
4165                    }
4166                    let end_region = cursor.region();
4167
4168                    // Convert the metadata item's range into multibuffer coordinates.
4169                    let mut start_position = start_region.range.start;
4170                    let region_buffer_start = start_region.buffer_range.start;
4171                    if start_region.is_main_buffer
4172                        && metadata_buffer_range.start > region_buffer_start
4173                    {
4174                        start_position =
4175                            start_position + (metadata_buffer_range.start - region_buffer_start);
4176                        start_position = start_position.min(start_region.range.end);
4177                    }
4178
4179                    let mut end_position = self.max_position();
4180                    if let Some(end_region) = &end_region {
4181                        end_position = end_region.range.start;
4182                        debug_assert!(end_region.is_main_buffer);
4183                        let region_buffer_start = end_region.buffer_range.start;
4184                        if metadata_buffer_range.end > region_buffer_start {
4185                            end_position =
4186                                end_position + (metadata_buffer_range.end - region_buffer_start);
4187                        }
4188                        end_position = end_position.min(end_region.range.end);
4189                    }
4190
4191                    if start_position <= query_range.end && end_position >= query_range.start {
4192                        return Some((start_position..end_position, metadata, excerpt));
4193                    }
4194                }
4195                // When there are no more metadata items for this excerpt, move to the next excerpt.
4196                else {
4197                    current_excerpt_metadata.take();
4198                    if let Some((end_excerpt_id, _)) = range_end
4199                        && excerpt.id == end_excerpt_id
4200                    {
4201                        return None;
4202                    }
4203                    cursor.next_excerpt();
4204                }
4205            }
4206        })
4207    }
4208
4209    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4210        let offset = position.to_offset(self);
4211
4212        let mut cursor = self
4213            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4214            );
4215        cursor.seek(&DimensionPair {
4216            key: offset,
4217            value: None,
4218        });
4219        cursor.seek_to_start_of_current_excerpt();
4220        let excerpt = cursor.excerpt()?;
4221
4222        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4223        let current_position = self
4224            .anchor_before(offset)
4225            .text_anchor
4226            .to_offset(&excerpt.buffer);
4227        let excerpt_end = excerpt
4228            .buffer
4229            .anchor_before(excerpt_end.min(current_position));
4230
4231        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4232            for hunk in diff.hunks_intersecting_range_rev(
4233                excerpt.range.context.start..excerpt_end,
4234                &excerpt.buffer,
4235            ) {
4236                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4237                if hunk_end >= current_position {
4238                    continue;
4239                }
4240                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4241                return Some(MultiBufferRow(start.row));
4242            }
4243        }
4244
4245        loop {
4246            cursor.prev_excerpt();
4247            let excerpt = cursor.excerpt()?;
4248
4249            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4250                continue;
4251            };
4252            let mut hunks =
4253                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4254            let Some(hunk) = hunks.next() else {
4255                continue;
4256            };
4257            let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4258            return Some(MultiBufferRow(start.row));
4259        }
4260    }
4261
4262    pub fn has_diff_hunks(&self) -> bool {
4263        self.diffs.values().any(|diff| !diff.is_empty())
4264    }
4265
4266    pub fn is_inside_word<T: ToOffset>(
4267        &self,
4268        position: T,
4269        scope_context: Option<CharScopeContext>,
4270    ) -> bool {
4271        let position = position.to_offset(self);
4272        let classifier = self
4273            .char_classifier_at(position)
4274            .scope_context(scope_context);
4275        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4276        let prev_char_kind = self
4277            .reversed_chars_at(position)
4278            .next()
4279            .map(|c| classifier.kind(c));
4280        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4281    }
4282
4283    pub fn surrounding_word<T: ToOffset>(
4284        &self,
4285        start: T,
4286        scope_context: Option<CharScopeContext>,
4287    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4288        let mut start = start.to_offset(self);
4289        let mut end = start;
4290        let mut next_chars = self.chars_at(start).peekable();
4291        let mut prev_chars = self.reversed_chars_at(start).peekable();
4292
4293        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4294
4295        let word_kind = cmp::max(
4296            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4297            next_chars.peek().copied().map(|c| classifier.kind(c)),
4298        );
4299
4300        for ch in prev_chars {
4301            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4302                start -= ch.len_utf8();
4303            } else {
4304                break;
4305            }
4306        }
4307
4308        for ch in next_chars {
4309            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4310                end += ch.len_utf8();
4311            } else {
4312                break;
4313            }
4314        }
4315
4316        (start..end, word_kind)
4317    }
4318
4319    pub fn char_kind_before<T: ToOffset>(
4320        &self,
4321        start: T,
4322        scope_context: Option<CharScopeContext>,
4323    ) -> Option<CharKind> {
4324        let start = start.to_offset(self);
4325        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4326        self.reversed_chars_at(start)
4327            .next()
4328            .map(|ch| classifier.kind(ch))
4329    }
4330
4331    pub fn is_singleton(&self) -> bool {
4332        self.singleton
4333    }
4334
4335    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4336        if self.singleton {
4337            self.excerpts
4338                .iter()
4339                .next()
4340                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4341        } else {
4342            None
4343        }
4344    }
4345
4346    pub fn len(&self) -> MultiBufferOffset {
4347        self.diff_transforms.summary().output.len
4348    }
4349
4350    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4351        MBD::from_summary(&self.text_summary())
4352    }
4353
4354    pub fn is_empty(&self) -> bool {
4355        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4356    }
4357
4358    pub fn widest_line_number(&self) -> u32 {
4359        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4360        self.excerpts.summary().widest_line_number + 1
4361    }
4362
4363    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4364        let range = range.start.to_offset(self)..range.end.to_offset(self);
4365        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4366        excerpts.seek(&range.start);
4367
4368        let mut chunk;
4369        let mut has_trailing_newline;
4370        let excerpt_bytes;
4371        if let Some(region) = excerpts.region() {
4372            let mut bytes = region.buffer.bytes_in_range(
4373                region.buffer_range.start + (range.start - region.range.start)
4374                    ..(region.buffer_range.start + (range.end - region.range.start))
4375                        .min(region.buffer_range.end),
4376            );
4377            chunk = bytes.next().unwrap_or(&[][..]);
4378            excerpt_bytes = Some(bytes);
4379            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4380            if chunk.is_empty() && has_trailing_newline {
4381                chunk = b"\n";
4382                has_trailing_newline = false;
4383            }
4384        } else {
4385            chunk = &[][..];
4386            excerpt_bytes = None;
4387            has_trailing_newline = false;
4388        };
4389
4390        MultiBufferBytes {
4391            range,
4392            cursor: excerpts,
4393            excerpt_bytes,
4394            has_trailing_newline,
4395            chunk,
4396        }
4397    }
4398
4399    pub fn reversed_bytes_in_range<T: ToOffset>(
4400        &self,
4401        range: Range<T>,
4402    ) -> ReversedMultiBufferBytes<'_> {
4403        let range = range.start.to_offset(self)..range.end.to_offset(self);
4404        let mut chunks = self.reversed_chunks_in_range(range.clone());
4405        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4406        ReversedMultiBufferBytes {
4407            range,
4408            chunks,
4409            chunk,
4410        }
4411    }
4412
4413    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4414        let mut cursor = self.cursor::<Point, Point>();
4415        cursor.seek(&Point::new(start_row.0, 0));
4416        let mut result = MultiBufferRows {
4417            point: Point::new(0, 0),
4418            is_empty: self.excerpts.is_empty(),
4419            is_singleton: self.is_singleton(),
4420            cursor,
4421        };
4422        result.seek(start_row);
4423        result
4424    }
4425
4426    pub fn chunks<T: ToOffset>(
4427        &self,
4428        range: Range<T>,
4429        language_aware: bool,
4430    ) -> MultiBufferChunks<'_> {
4431        let mut chunks = MultiBufferChunks {
4432            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4433                ..ExcerptDimension(MultiBufferOffset::ZERO),
4434            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4435            excerpts: self.excerpts.cursor(()),
4436            diff_transforms: self.diff_transforms.cursor(()),
4437            diffs: &self.diffs,
4438            diff_base_chunks: None,
4439            excerpt_chunks: None,
4440            buffer_chunk: None,
4441            language_aware,
4442        };
4443        let range = range.start.to_offset(self)..range.end.to_offset(self);
4444        chunks.seek(range);
4445        chunks
4446    }
4447
4448    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4449        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4450    }
4451
4452    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4453        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4454    }
4455
4456    pub fn clip_offset_utf16(
4457        &self,
4458        offset: MultiBufferOffsetUtf16,
4459        bias: Bias,
4460    ) -> MultiBufferOffsetUtf16 {
4461        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4462    }
4463
4464    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4465        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4466            buffer.clip_point_utf16(Unclipped(point), bias)
4467        })
4468    }
4469
4470    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4471        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4472    }
4473
4474    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4475        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4476    }
4477
4478    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4479        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4480    }
4481
4482    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4483        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4484    }
4485
4486    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4487        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4488    }
4489
4490    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4491        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4492    }
4493
4494    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4495        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4496    }
4497
4498    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4499        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4500    }
4501
4502    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4503        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4504    }
4505
4506    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4507        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4508    }
4509
4510    fn clip_dimension<MBD, BD>(
4511        &self,
4512        position: MBD,
4513        bias: Bias,
4514        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4515    ) -> MBD
4516    where
4517        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4518        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4519    {
4520        let mut cursor = self.cursor::<MBD, BD>();
4521        cursor.seek(&position);
4522        if let Some(region) = cursor.region() {
4523            if position >= region.range.end {
4524                return region.range.end;
4525            }
4526            let overshoot = position - region.range.start;
4527            let mut buffer_position = region.buffer_range.start;
4528            buffer_position += overshoot;
4529            let clipped_buffer_position =
4530                clip_buffer_position(region.buffer, buffer_position, bias);
4531            let mut position = region.range.start;
4532            position += clipped_buffer_position - region.buffer_range.start;
4533            position
4534        } else {
4535            self.max_position()
4536        }
4537    }
4538
4539    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4540        &self,
4541        key: MBR1,
4542        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4543    ) -> MBR2
4544    where
4545        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4546        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4547        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4548        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4549    {
4550        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4551        cursor.seek(&DimensionPair { key, value: None });
4552        if let Some(region) = cursor.region() {
4553            if key >= region.range.end.key {
4554                return region.range.end.value.unwrap();
4555            }
4556            let start_key = region.range.start.key;
4557            let start_value = region.range.start.value.unwrap();
4558            let buffer_start_key = region.buffer_range.start.key;
4559            let buffer_start_value = region.buffer_range.start.value.unwrap();
4560            let mut buffer_key = buffer_start_key;
4561            buffer_key += key - start_key;
4562            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4563            let mut result = start_value;
4564            result += buffer_value - buffer_start_value;
4565            result
4566        } else {
4567            self.max_position()
4568        }
4569    }
4570
4571    pub fn point_to_buffer_offset<T: ToOffset>(
4572        &self,
4573        point: T,
4574    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4575        let offset = point.to_offset(self);
4576        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4577        cursor.seek(&offset);
4578        let region = cursor.region()?;
4579        let overshoot = offset - region.range.start;
4580        let buffer_offset = region.buffer_range.start + overshoot;
4581        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4582            && region.has_trailing_newline
4583            && !region.is_main_buffer
4584        {
4585            let main_buffer_position = cursor.main_buffer_position()?;
4586            let buffer_snapshot = &cursor.excerpt()?.buffer;
4587            return Some((buffer_snapshot, main_buffer_position));
4588        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4589            return None;
4590        }
4591        Some((region.buffer, buffer_offset))
4592    }
4593
4594    pub fn point_to_buffer_point(
4595        &self,
4596        point: Point,
4597    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4598        let mut cursor = self.cursor::<Point, Point>();
4599        cursor.seek(&point);
4600        let region = cursor.region()?;
4601        let overshoot = point - region.range.start;
4602        let buffer_point = region.buffer_range.start + overshoot;
4603        let excerpt = cursor.excerpt()?;
4604        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4605            && region.has_trailing_newline
4606            && !region.is_main_buffer
4607        {
4608            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4609        } else if buffer_point > region.buffer.max_point() {
4610            return None;
4611        }
4612        Some((region.buffer, buffer_point, excerpt.id))
4613    }
4614
4615    pub fn suggested_indents(
4616        &self,
4617        rows: impl IntoIterator<Item = u32>,
4618        cx: &App,
4619    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4620        let mut result = BTreeMap::new();
4621        self.suggested_indents_callback(
4622            rows,
4623            |row, indent| {
4624                result.insert(row, indent);
4625                ControlFlow::Continue(())
4626            },
4627            cx,
4628        );
4629        result
4630    }
4631
4632    // move this to be a generator once those are a thing
4633    pub fn suggested_indents_callback(
4634        &self,
4635        rows: impl IntoIterator<Item = u32>,
4636        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4637        cx: &App,
4638    ) {
4639        let mut rows_for_excerpt = Vec::new();
4640        let mut cursor = self.cursor::<Point, Point>();
4641        let mut rows = rows.into_iter().peekable();
4642        let mut prev_row = u32::MAX;
4643        let mut prev_language_indent_size = IndentSize::default();
4644
4645        while let Some(row) = rows.next() {
4646            cursor.seek(&Point::new(row, 0));
4647            let Some(region) = cursor.region() else {
4648                continue;
4649            };
4650
4651            // Retrieve the language and indent size once for each disjoint region being indented.
4652            let single_indent_size = if row.saturating_sub(1) == prev_row {
4653                prev_language_indent_size
4654            } else {
4655                region
4656                    .buffer
4657                    .language_indent_size_at(Point::new(row, 0), cx)
4658            };
4659            prev_language_indent_size = single_indent_size;
4660            prev_row = row;
4661
4662            let start_buffer_row = region.buffer_range.start.row;
4663            let start_multibuffer_row = region.range.start.row;
4664            let end_multibuffer_row = region.range.end.row;
4665
4666            rows_for_excerpt.push(row);
4667            while let Some(next_row) = rows.peek().copied() {
4668                if end_multibuffer_row > next_row {
4669                    rows_for_excerpt.push(next_row);
4670                    rows.next();
4671                } else {
4672                    break;
4673                }
4674            }
4675
4676            let buffer_rows = rows_for_excerpt
4677                .drain(..)
4678                .map(|row| start_buffer_row + row - start_multibuffer_row);
4679            let buffer_indents = region
4680                .buffer
4681                .suggested_indents(buffer_rows, single_indent_size);
4682            for (row, indent) in buffer_indents {
4683                if cb(
4684                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4685                    indent,
4686                )
4687                .is_break()
4688                {
4689                    return;
4690                }
4691            }
4692        }
4693    }
4694
4695    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4696        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4697            let mut size = buffer.indent_size_for_line(range.start.row);
4698            size.len = size
4699                .len
4700                .min(range.end.column)
4701                .saturating_sub(range.start.column);
4702            size
4703        } else {
4704            IndentSize::spaces(0)
4705        }
4706    }
4707
4708    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4709        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4710            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4711        } else {
4712            LineIndent::spaces(0)
4713        }
4714    }
4715
4716    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4717        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4718
4719        if self.language_settings(cx).extend_comment_on_newline
4720            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4721        {
4722            let delimiters = language_scope.line_comment_prefixes();
4723            for delimiter in delimiters {
4724                if *self
4725                    .chars_at(Point::new(row.0, indent.len() as u32))
4726                    .take(delimiter.chars().count())
4727                    .collect::<String>()
4728                    .as_str()
4729                    == **delimiter
4730                {
4731                    indent.push_str(delimiter);
4732                    break;
4733                }
4734            }
4735        }
4736
4737        indent
4738    }
4739
4740    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4741    where
4742        T: ToOffset,
4743    {
4744        for char in self.reversed_chars_at(position) {
4745            if !char.is_whitespace() {
4746                return false;
4747            }
4748            if char == '\n' {
4749                return true;
4750            }
4751        }
4752        true
4753    }
4754
4755    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4756        while row.0 > 0 {
4757            row.0 -= 1;
4758            if !self.is_line_blank(row) {
4759                return Some(row);
4760            }
4761        }
4762        None
4763    }
4764
4765    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4766        if let Some((_, range)) = self.buffer_line_for_row(row) {
4767            range.end.column - range.start.column
4768        } else {
4769            0
4770        }
4771    }
4772
4773    pub fn buffer_line_for_row(
4774        &self,
4775        row: MultiBufferRow,
4776    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4777        let mut cursor = self.cursor::<Point, Point>();
4778        let point = Point::new(row.0, 0);
4779        cursor.seek(&point);
4780        let region = cursor.region()?;
4781        let overshoot = point.min(region.range.end) - region.range.start;
4782        let buffer_point = region.buffer_range.start + overshoot;
4783        if buffer_point.row > region.buffer_range.end.row {
4784            return None;
4785        }
4786        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4787        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4788            .min(region.buffer_range.end);
4789        Some((region.buffer, line_start..line_end))
4790    }
4791
4792    pub fn max_point(&self) -> Point {
4793        self.text_summary().lines
4794    }
4795
4796    pub fn max_row(&self) -> MultiBufferRow {
4797        MultiBufferRow(self.text_summary().lines.row)
4798    }
4799
4800    pub fn text_summary(&self) -> MBTextSummary {
4801        self.diff_transforms.summary().output
4802    }
4803
4804    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4805    where
4806        MBD: MultiBufferDimension + AddAssign,
4807        O: ToOffset,
4808    {
4809        let range = range.start.to_offset(self)..range.end.to_offset(self);
4810        let mut cursor = self
4811            .diff_transforms
4812            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4813        cursor.seek(&range.start, Bias::Right);
4814
4815        let Some(first_transform) = cursor.item() else {
4816            return MBD::from_summary(&MBTextSummary::default());
4817        };
4818
4819        let diff_transform_start = cursor.start().0;
4820        let diff_transform_end = cursor.end().0;
4821        let diff_start = range.start;
4822        let start_overshoot = diff_start - diff_transform_start;
4823        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4824
4825        let mut result = match first_transform {
4826            DiffTransform::Unmodified { .. } | DiffTransform::InsertedHunk { .. } => {
4827                let excerpt_start = cursor.start().1 + start_overshoot;
4828                let excerpt_end = cursor.start().1 + end_overshoot;
4829                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4830            }
4831            DiffTransform::FilteredInsertedHunk { .. } => MBD::default(),
4832            DiffTransform::DeletedHunk {
4833                buffer_id,
4834                has_trailing_newline,
4835                hunk_info,
4836                ..
4837            } => {
4838                let buffer_start = hunk_info.base_text_byte_range.start + start_overshoot;
4839                let mut buffer_end = hunk_info.base_text_byte_range.start + end_overshoot;
4840                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4841                    panic!("{:?} is in non-existent deleted hunk", range.start)
4842                };
4843
4844                let include_trailing_newline =
4845                    *has_trailing_newline && range.end >= diff_transform_end;
4846                if include_trailing_newline {
4847                    buffer_end -= 1;
4848                }
4849
4850                let mut summary = base_text
4851                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4852
4853                if include_trailing_newline {
4854                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4855                        &TextSummary::newline(),
4856                    ))
4857                }
4858
4859                let mut result = MBD::default();
4860                result.add_text_dim(&summary);
4861                result
4862            }
4863        };
4864        if range.end < diff_transform_end {
4865            return result;
4866        }
4867
4868        cursor.next();
4869        result.add_mb_text_summary(
4870            &cursor
4871                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4872                .0,
4873        );
4874
4875        let Some(last_transform) = cursor.item() else {
4876            return result;
4877        };
4878
4879        let overshoot = range.end - cursor.start().0;
4880        let suffix = match last_transform {
4881            DiffTransform::Unmodified { .. } | DiffTransform::InsertedHunk { .. } => {
4882                let end = cursor.start().1 + overshoot;
4883                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4884            }
4885            DiffTransform::FilteredInsertedHunk { .. } => MBD::default(),
4886            DiffTransform::DeletedHunk {
4887                buffer_id,
4888                has_trailing_newline,
4889                hunk_info,
4890                ..
4891            } => {
4892                let buffer_end = hunk_info.base_text_byte_range.start + overshoot;
4893                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4894                    panic!("{:?} is in non-existent deleted hunk", range.end)
4895                };
4896
4897                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4898                    hunk_info.base_text_byte_range.start..buffer_end,
4899                );
4900                if *has_trailing_newline && buffer_end == hunk_info.base_text_byte_range.end + 1 {
4901                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4902                        &TextSummary::from("\n"),
4903                    ))
4904                }
4905
4906                let mut result = MBD::default();
4907                result.add_text_dim(&suffix);
4908                result
4909            }
4910        };
4911
4912        result += suffix;
4913        result
4914    }
4915
4916    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4917    where
4918        MBD: MultiBufferDimension + AddAssign,
4919    {
4920        let mut summary = MBD::default();
4921        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4922        cursor.seek(&range.start, Bias::Right);
4923        if let Some(excerpt) = cursor.item() {
4924            let mut end_before_newline = cursor.end();
4925            if excerpt.has_trailing_newline {
4926                end_before_newline -= 1;
4927            }
4928
4929            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4930            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4931            let end_in_excerpt =
4932                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4933            summary.add_text_dim(
4934                &excerpt
4935                    .buffer
4936                    .text_summary_for_range::<MBD::TextDimension, _>(
4937                        start_in_excerpt..end_in_excerpt,
4938                    ),
4939            );
4940
4941            if range.end > end_before_newline {
4942                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4943            }
4944
4945            cursor.next();
4946        }
4947
4948        if range.end > *cursor.start() {
4949            summary += cursor
4950                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4951                .0;
4952            if let Some(excerpt) = cursor.item() {
4953                range.end = cmp::max(*cursor.start(), range.end);
4954
4955                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4956                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4957                summary.add_text_dim(
4958                    &excerpt
4959                        .buffer
4960                        .text_summary_for_range::<MBD::TextDimension, _>(
4961                            excerpt_start..end_in_excerpt,
4962                        ),
4963                );
4964            }
4965        }
4966
4967        summary
4968    }
4969
4970    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4971    where
4972        MBD: MultiBufferDimension
4973            + Ord
4974            + Sub<Output = MBD::TextDimension>
4975            + AddAssign<MBD::TextDimension>,
4976        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4977    {
4978        self.summaries_for_anchors([anchor])[0]
4979    }
4980
4981    fn resolve_summary_for_anchor<MBD>(
4982        &self,
4983        anchor: &Anchor,
4984        excerpt_position: ExcerptDimension<MBD>,
4985        diff_transforms: &mut Cursor<
4986            DiffTransform,
4987            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4988        >,
4989    ) -> MBD
4990    where
4991        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4992    {
4993        loop {
4994            let transform_end_position = diff_transforms.end().0;
4995            let at_transform_end =
4996                transform_end_position == excerpt_position && diff_transforms.item().is_some();
4997            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4998                diff_transforms.next();
4999                continue;
5000            }
5001
5002            let mut position = diff_transforms.start().1;
5003            match diff_transforms.item() {
5004                Some(DiffTransform::DeletedHunk {
5005                    buffer_id,
5006                    hunk_info,
5007                    ..
5008                }) => {
5009                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5010                        && let Some(base_text) =
5011                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5012                        && base_text.can_resolve(diff_base_anchor)
5013                    {
5014                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5015                        if base_text_offset >= hunk_info.base_text_byte_range.start
5016                            && base_text_offset <= hunk_info.base_text_byte_range.end
5017                        {
5018                            let position_in_hunk = base_text
5019                                .text_summary_for_range::<MBD::TextDimension, _>(
5020                                    hunk_info.base_text_byte_range.start..base_text_offset,
5021                                );
5022                            position.0.add_text_dim(&position_in_hunk);
5023                        } else if at_transform_end {
5024                            diff_transforms.next();
5025                            continue;
5026                        }
5027                    }
5028                }
5029                _ => {
5030                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5031                        diff_transforms.next();
5032                        continue;
5033                    }
5034
5035                    if !matches!(
5036                        diff_transforms.item(),
5037                        Some(DiffTransform::FilteredInsertedHunk { .. })
5038                    ) {
5039                        let overshoot = excerpt_position - diff_transforms.start().0;
5040                        position += overshoot;
5041                    }
5042                }
5043            }
5044
5045            return position.0;
5046        }
5047    }
5048
5049    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5050        let mut cursor = self
5051            .excerpts
5052            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5053        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5054
5055        cursor.seek(&Some(locator), Bias::Left);
5056        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5057            cursor.prev();
5058        }
5059
5060        let mut position = cursor.start().1;
5061        if let Some(excerpt) = cursor.item()
5062            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5063        {
5064            let excerpt_buffer_start = excerpt
5065                .buffer
5066                .offset_for_anchor(&excerpt.range.context.start);
5067            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5068            let buffer_position = cmp::min(
5069                excerpt_buffer_end,
5070                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5071            );
5072            if buffer_position > excerpt_buffer_start {
5073                position += buffer_position - excerpt_buffer_start;
5074            }
5075        }
5076        position
5077    }
5078
5079    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5080        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5081            excerpt_id = *replacement;
5082        }
5083        excerpt_id
5084    }
5085
5086    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5087    where
5088        MBD: MultiBufferDimension
5089            + Ord
5090            + Sub<Output = MBD::TextDimension>
5091            + AddAssign<MBD::TextDimension>,
5092        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5093        I: 'a + IntoIterator<Item = &'a Anchor>,
5094    {
5095        let mut anchors = anchors.into_iter().peekable();
5096        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5097        let mut diff_transforms_cursor = self
5098            .diff_transforms
5099            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5100        diff_transforms_cursor.next();
5101
5102        let mut summaries = Vec::new();
5103        while let Some(anchor) = anchors.peek() {
5104            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5105
5106            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5107                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5108            });
5109
5110            let locator = self.excerpt_locator_for_id(excerpt_id);
5111            cursor.seek_forward(locator, Bias::Left);
5112            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5113                cursor.prev();
5114            }
5115
5116            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5117            if let Some(excerpt) = cursor.item() {
5118                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5119                    let position = self.resolve_summary_for_anchor(
5120                        &Anchor::min(),
5121                        excerpt_start_position,
5122                        &mut diff_transforms_cursor,
5123                    );
5124                    summaries.extend(excerpt_anchors.map(|_| position));
5125                    continue;
5126                }
5127                let excerpt_buffer_start = excerpt
5128                    .range
5129                    .context
5130                    .start
5131                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5132                let excerpt_buffer_end = excerpt
5133                    .range
5134                    .context
5135                    .end
5136                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5137                for (buffer_summary, anchor) in excerpt
5138                    .buffer
5139                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5140                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5141                    )
5142                {
5143                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5144                    let mut position = excerpt_start_position;
5145                    if summary > excerpt_buffer_start {
5146                        position += summary - excerpt_buffer_start;
5147                    }
5148
5149                    if diff_transforms_cursor.start().0 < position {
5150                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5151                    }
5152
5153                    summaries.push(self.resolve_summary_for_anchor(
5154                        anchor,
5155                        position,
5156                        &mut diff_transforms_cursor,
5157                    ));
5158                }
5159            } else {
5160                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5161                let position = self.resolve_summary_for_anchor(
5162                    &Anchor::max(),
5163                    excerpt_start_position,
5164                    &mut diff_transforms_cursor,
5165                );
5166                summaries.extend(excerpt_anchors.map(|_| position));
5167            }
5168        }
5169
5170        summaries
5171    }
5172
5173    pub fn dimensions_from_points<'a, MBD>(
5174        &'a self,
5175        points: impl 'a + IntoIterator<Item = Point>,
5176    ) -> impl 'a + Iterator<Item = MBD>
5177    where
5178        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5179    {
5180        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5181        cursor.seek(&DimensionPair {
5182            key: Point::default(),
5183            value: None,
5184        });
5185        let mut points = points.into_iter();
5186        iter::from_fn(move || {
5187            let point = points.next()?;
5188
5189            cursor.seek_forward(&DimensionPair {
5190                key: point,
5191                value: None,
5192            });
5193
5194            if let Some(region) = cursor.region() {
5195                let overshoot = point - region.range.start.key;
5196                let buffer_point = region.buffer_range.start + overshoot;
5197                let mut position = region.range.start.value.unwrap();
5198                position.add_text_dim(
5199                    &region
5200                        .buffer
5201                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5202                );
5203                if point == region.range.end.key && region.has_trailing_newline {
5204                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5205                }
5206                Some(position)
5207            } else {
5208                Some(MBD::from_summary(&self.text_summary()))
5209            }
5210        })
5211    }
5212
5213    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5214    where
5215        I: 'a + IntoIterator<Item = &'a Anchor>,
5216    {
5217        let mut anchors = anchors.into_iter().enumerate().peekable();
5218        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5219        cursor.next();
5220
5221        let mut result = Vec::new();
5222
5223        while let Some((_, anchor)) = anchors.peek() {
5224            let old_excerpt_id = anchor.excerpt_id;
5225
5226            // Find the location where this anchor's excerpt should be.
5227            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5228            cursor.seek_forward(&Some(old_locator), Bias::Left);
5229
5230            let next_excerpt = cursor.item();
5231            let prev_excerpt = cursor.prev_item();
5232
5233            // Process all of the anchors for this excerpt.
5234            while let Some((anchor_ix, &anchor)) =
5235                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5236            {
5237                let mut anchor = anchor;
5238
5239                // Leave min and max anchors unchanged if invalid or
5240                // if the old excerpt still exists at this location
5241                let mut kept_position = next_excerpt
5242                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5243                    || old_excerpt_id == ExcerptId::max()
5244                    || old_excerpt_id == ExcerptId::min();
5245
5246                // If the old excerpt no longer exists at this location, then attempt to
5247                // find an equivalent position for this anchor in an adjacent excerpt.
5248                if !kept_position {
5249                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5250                        if excerpt.contains(&anchor) {
5251                            anchor.excerpt_id = excerpt.id;
5252                            kept_position = true;
5253                            break;
5254                        }
5255                    }
5256                }
5257
5258                // If there's no adjacent excerpt that contains the anchor's position,
5259                // then report that the anchor has lost its position.
5260                if !kept_position {
5261                    anchor = if let Some(excerpt) = next_excerpt {
5262                        let mut text_anchor = excerpt
5263                            .range
5264                            .context
5265                            .start
5266                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5267                        if text_anchor
5268                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5269                            .is_gt()
5270                        {
5271                            text_anchor = excerpt.range.context.end;
5272                        }
5273                        Anchor::in_buffer(excerpt.id, text_anchor)
5274                    } else if let Some(excerpt) = prev_excerpt {
5275                        let mut text_anchor = excerpt
5276                            .range
5277                            .context
5278                            .end
5279                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5280                        if text_anchor
5281                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5282                            .is_lt()
5283                        {
5284                            text_anchor = excerpt.range.context.start;
5285                        }
5286                        Anchor::in_buffer(excerpt.id, text_anchor)
5287                    } else if anchor.text_anchor.bias == Bias::Left {
5288                        Anchor::min()
5289                    } else {
5290                        Anchor::max()
5291                    };
5292                }
5293
5294                result.push((anchor_ix, anchor, kept_position));
5295            }
5296        }
5297        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5298        result
5299    }
5300
5301    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5302        self.anchor_at(position, Bias::Left)
5303    }
5304
5305    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5306        self.anchor_at(position, Bias::Right)
5307    }
5308
5309    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5310        let offset = position.to_offset(self);
5311
5312        // Find the given position in the diff transforms. Determine the corresponding
5313        // offset in the excerpts, and whether the position is within a deleted hunk.
5314        let mut diff_transforms = self
5315            .diff_transforms
5316            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5317        diff_transforms.seek(&offset, Bias::Right);
5318
5319        if offset == diff_transforms.start().0
5320            && bias == Bias::Left
5321            && let Some(prev_item) = diff_transforms.prev_item()
5322            && let DiffTransform::DeletedHunk { .. } = prev_item
5323        {
5324            diff_transforms.prev();
5325        }
5326        let offset_in_transform = offset - diff_transforms.start().0;
5327        let mut excerpt_offset = diff_transforms.start().1;
5328        let mut diff_base_anchor = None;
5329        if let Some(DiffTransform::DeletedHunk {
5330            buffer_id,
5331            has_trailing_newline,
5332            hunk_info,
5333            ..
5334        }) = diff_transforms.item()
5335        {
5336            let base_text_byte_range = &hunk_info.base_text_byte_range;
5337            let diff = self.diffs.get(buffer_id).expect("missing diff");
5338            if offset_in_transform > base_text_byte_range.len() {
5339                debug_assert!(*has_trailing_newline);
5340                bias = Bias::Right;
5341            } else {
5342                diff_base_anchor = Some(
5343                    diff.base_text()
5344                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5345                );
5346                bias = Bias::Left;
5347            }
5348        } else {
5349            excerpt_offset += MultiBufferOffset(offset_in_transform);
5350        };
5351
5352        let mut excerpts = self
5353            .excerpts
5354            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5355        excerpts.seek(&excerpt_offset, Bias::Right);
5356        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5357            excerpts.prev();
5358        }
5359        if let Some(excerpt) = excerpts.item() {
5360            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5361            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5362                overshoot -= 1;
5363                bias = Bias::Right;
5364            }
5365
5366            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5367            let text_anchor =
5368                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5369            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5370            match diff_base_anchor {
5371                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5372                None => anchor,
5373            }
5374        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5375        {
5376            Anchor::min()
5377        } else {
5378            Anchor::max()
5379        }
5380    }
5381
5382    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5383    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5384        let (excerpt, buffer, _) = self.as_singleton()?;
5385        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5386            Some(Anchor::in_buffer(*excerpt, text_anchor))
5387        } else {
5388            None
5389        }
5390    }
5391
5392    /// Returns an anchor for the given excerpt and text anchor,
5393    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5394    pub fn anchor_range_in_excerpt(
5395        &self,
5396        excerpt_id: ExcerptId,
5397        text_anchor: Range<text::Anchor>,
5398    ) -> Option<Range<Anchor>> {
5399        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5400
5401        Some(
5402            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5403                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5404        )
5405    }
5406
5407    /// Returns an anchor for the given excerpt and text anchor,
5408    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5409    pub fn anchor_in_excerpt(
5410        &self,
5411        excerpt_id: ExcerptId,
5412        text_anchor: text::Anchor,
5413    ) -> Option<Anchor> {
5414        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5415        Self::anchor_in_excerpt_(excerpt, text_anchor)
5416    }
5417
5418    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5419    pub fn anchors_in_excerpt(
5420        &self,
5421        excerpt_id: ExcerptId,
5422        text_anchors: impl IntoIterator<Item = text::Anchor>,
5423    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5424        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5425        Some(
5426            text_anchors
5427                .into_iter()
5428                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5429        )
5430    }
5431
5432    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5433        match text_anchor.buffer_id {
5434            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5435            Some(_) => return None,
5436            None if text_anchor.is_max() || text_anchor.is_min() => {
5437                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5438            }
5439            None => return None,
5440        }
5441
5442        let context = &excerpt.range.context;
5443        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5444            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5445        {
5446            return None;
5447        }
5448
5449        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5450    }
5451
5452    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5453        Some(self.excerpt(excerpt_id)?.range.context.clone())
5454    }
5455
5456    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5457        if anchor.is_min() || anchor.is_max() {
5458            // todo(lw): should be `!self.is_empty()`
5459            true
5460        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5461            excerpt.buffer.can_resolve(&anchor.text_anchor)
5462        } else {
5463            false
5464        }
5465    }
5466
5467    pub fn excerpts(
5468        &self,
5469    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5470        self.excerpts
5471            .iter()
5472            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5473    }
5474
5475    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5476    where
5477        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5478        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5479    {
5480        let excerpts = self.excerpts.cursor(());
5481        let diff_transforms = self.diff_transforms.cursor(());
5482        MultiBufferCursor {
5483            excerpts,
5484            diff_transforms,
5485            snapshot: &self,
5486            cached_region: None,
5487        }
5488    }
5489
5490    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5491        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5492        let mut excerpts = self
5493            .excerpts
5494            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5495        excerpts.seek(&Some(start_locator), Bias::Left);
5496        excerpts.prev();
5497
5498        let mut diff_transforms = self
5499            .diff_transforms
5500            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5501        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5502        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5503            diff_transforms.next();
5504        }
5505
5506        let excerpt = excerpts.item()?;
5507        Some(MultiBufferExcerpt {
5508            excerpt,
5509            offset: diff_transforms.start().output_dimension.0,
5510            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5511            excerpt_offset: excerpts.start().1,
5512            diff_transforms,
5513        })
5514    }
5515
5516    pub fn excerpt_boundaries_in_range<R, T>(
5517        &self,
5518        range: R,
5519    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5520    where
5521        R: RangeBounds<T>,
5522        T: ToOffset,
5523    {
5524        let start_offset;
5525        let start = match range.start_bound() {
5526            Bound::Included(start) => {
5527                start_offset = start.to_offset(self);
5528                Bound::Included(start_offset)
5529            }
5530            Bound::Excluded(_) => {
5531                panic!("not supported")
5532            }
5533            Bound::Unbounded => {
5534                start_offset = MultiBufferOffset::ZERO;
5535                Bound::Unbounded
5536            }
5537        };
5538        let end = match range.end_bound() {
5539            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5540            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5541            Bound::Unbounded => Bound::Unbounded,
5542        };
5543        let bounds = (start, end);
5544        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5545        cursor.seek(&DimensionPair {
5546            key: start_offset,
5547            value: None,
5548        });
5549
5550        if cursor
5551            .region()
5552            .is_some_and(|region| bounds.contains(&region.range.start.key))
5553        {
5554            cursor.prev_excerpt();
5555        } else {
5556            cursor.seek_to_start_of_current_excerpt();
5557        }
5558        let mut prev_region = cursor.region();
5559
5560        cursor.next_excerpt();
5561
5562        iter::from_fn(move || {
5563            loop {
5564                if self.singleton {
5565                    return None;
5566                }
5567
5568                let next_region = cursor.region()?;
5569                cursor.next_excerpt();
5570                if !bounds.contains(&next_region.range.start.key) {
5571                    prev_region = Some(next_region);
5572                    continue;
5573                }
5574
5575                let next_region_start = next_region.range.start.value.unwrap();
5576                let next_region_end = if let Some(region) = cursor.region() {
5577                    region.range.start.value.unwrap()
5578                } else {
5579                    self.max_point()
5580                };
5581
5582                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5583                    id: region.excerpt.id,
5584                    buffer: region.excerpt.buffer.clone(),
5585                    buffer_id: region.excerpt.buffer_id,
5586                    range: region.excerpt.range.clone(),
5587                    end_row: MultiBufferRow(next_region_start.row),
5588                });
5589
5590                let next = ExcerptInfo {
5591                    id: next_region.excerpt.id,
5592                    buffer: next_region.excerpt.buffer.clone(),
5593                    buffer_id: next_region.excerpt.buffer_id,
5594                    range: next_region.excerpt.range.clone(),
5595                    end_row: if next_region.excerpt.has_trailing_newline {
5596                        MultiBufferRow(next_region_end.row - 1)
5597                    } else {
5598                        MultiBufferRow(next_region_end.row)
5599                    },
5600                };
5601
5602                let row = MultiBufferRow(next_region_start.row);
5603
5604                prev_region = Some(next_region);
5605
5606                return Some(ExcerptBoundary { row, prev, next });
5607            }
5608        })
5609    }
5610
5611    pub fn edit_count(&self) -> usize {
5612        self.edit_count
5613    }
5614
5615    pub fn non_text_state_update_count(&self) -> usize {
5616        self.non_text_state_update_count
5617    }
5618
5619    /// Returns the smallest enclosing bracket ranges containing the given range or
5620    /// None if no brackets contain range or the range is not contained in a single
5621    /// excerpt
5622    ///
5623    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5624    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5625        &self,
5626        range: Range<T>,
5627        range_filter: Option<
5628            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5629        >,
5630    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5631        let range = range.start.to_offset(self)..range.end.to_offset(self);
5632        let mut excerpt = self.excerpt_containing(range.clone())?;
5633        let buffer = excerpt.buffer();
5634        let excerpt_buffer_range = excerpt.buffer_range();
5635
5636        // Filter to ranges contained in the excerpt
5637        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5638            excerpt_buffer_range.contains(&BufferOffset(open.start))
5639                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5640                && range_filter.is_none_or(|filter| {
5641                    filter(
5642                        buffer,
5643                        BufferOffset(open.start)..BufferOffset(close.end),
5644                        BufferOffset(close.start)..BufferOffset(close.end),
5645                    )
5646                })
5647        };
5648
5649        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5650            excerpt.map_range_to_buffer(range),
5651            Some(&range_filter),
5652        )?;
5653
5654        Some((
5655            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5656            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5657        ))
5658    }
5659
5660    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5661    /// not contained in a single excerpt
5662    pub fn enclosing_bracket_ranges<T: ToOffset>(
5663        &self,
5664        range: Range<T>,
5665    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5666    {
5667        let range = range.start.to_offset(self)..range.end.to_offset(self);
5668        let mut excerpt = self.excerpt_containing(range.clone())?;
5669
5670        Some(
5671            excerpt
5672                .buffer()
5673                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5674                .filter_map(move |pair| {
5675                    let open_range =
5676                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5677                    let close_range =
5678                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5679                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5680                        Some((
5681                            excerpt.map_range_from_buffer(open_range),
5682                            excerpt.map_range_from_buffer(close_range),
5683                        ))
5684                    } else {
5685                        None
5686                    }
5687                }),
5688        )
5689    }
5690
5691    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5692    /// not contained in a single excerpt
5693    pub fn text_object_ranges<T: ToOffset>(
5694        &self,
5695        range: Range<T>,
5696        options: TreeSitterOptions,
5697    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5698        let range = range.start.to_offset(self)..range.end.to_offset(self);
5699        self.excerpt_containing(range.clone())
5700            .map(|mut excerpt| {
5701                excerpt
5702                    .buffer()
5703                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5704                    .filter_map(move |(range, text_object)| {
5705                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5706                        if excerpt.contains_buffer_range(range.clone()) {
5707                            Some((excerpt.map_range_from_buffer(range), text_object))
5708                        } else {
5709                            None
5710                        }
5711                    })
5712            })
5713            .into_iter()
5714            .flatten()
5715    }
5716
5717    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5718    /// not contained in a single excerpt
5719    pub fn bracket_ranges<T: ToOffset>(
5720        &self,
5721        range: Range<T>,
5722    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5723    {
5724        let range = range.start.to_offset(self)..range.end.to_offset(self);
5725        let mut excerpt = self.excerpt_containing(range.clone())?;
5726        Some(
5727            excerpt
5728                .buffer()
5729                .bracket_ranges(excerpt.map_range_to_buffer(range))
5730                .filter_map(move |pair| {
5731                    let open_range =
5732                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5733                    let close_range =
5734                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5735                    excerpt
5736                        .contains_buffer_range(open_range.start..close_range.end)
5737                        .then(|| BracketMatch {
5738                            open_range: excerpt.map_range_from_buffer(open_range),
5739                            close_range: excerpt.map_range_from_buffer(close_range),
5740                            color_index: pair.color_index,
5741                            newline_only: pair.newline_only,
5742                            syntax_layer_depth: pair.syntax_layer_depth,
5743                        })
5744                })
5745                .map(BracketMatch::bracket_ranges),
5746        )
5747    }
5748
5749    pub fn redacted_ranges<'a, T: ToOffset>(
5750        &'a self,
5751        range: Range<T>,
5752        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5753    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5754        let range = range.start.to_offset(self)..range.end.to_offset(self);
5755        self.lift_buffer_metadata(range, move |buffer, range| {
5756            if redaction_enabled(buffer.file()) {
5757                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5758            } else {
5759                None
5760            }
5761        })
5762        .map(|(range, _, _)| range)
5763    }
5764
5765    pub fn runnable_ranges(
5766        &self,
5767        range: Range<Anchor>,
5768    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5769        let range = range.start.to_offset(self)..range.end.to_offset(self);
5770        self.lift_buffer_metadata(range, move |buffer, range| {
5771            Some(
5772                buffer
5773                    .runnable_ranges(range.clone())
5774                    .filter(move |runnable| {
5775                        runnable.run_range.start >= range.start
5776                            && runnable.run_range.end < range.end
5777                    })
5778                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5779            )
5780        })
5781        .map(|(run_range, runnable, _)| (run_range, runnable))
5782    }
5783
5784    pub fn line_indents(
5785        &self,
5786        start_row: MultiBufferRow,
5787        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5788    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5789        let max_point = self.max_point();
5790        let mut cursor = self.cursor::<Point, Point>();
5791        cursor.seek(&Point::new(start_row.0, 0));
5792        iter::from_fn(move || {
5793            let mut region = cursor.region()?;
5794            while !buffer_filter(&region.excerpt.buffer) {
5795                cursor.next();
5796                region = cursor.region()?;
5797            }
5798            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5799            let buffer_start_row =
5800                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5801
5802            let buffer_end_row = if region.is_main_buffer
5803                && (region.has_trailing_newline || region.range.end == max_point)
5804            {
5805                region.buffer_range.end.row
5806            } else {
5807                region.buffer_range.end.row.saturating_sub(1)
5808            };
5809
5810            let line_indents = region
5811                .buffer
5812                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5813            cursor.next();
5814            Some(line_indents.map(move |(buffer_row, indent)| {
5815                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5816                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5817            }))
5818        })
5819        .flatten()
5820    }
5821
5822    pub fn reversed_line_indents(
5823        &self,
5824        end_row: MultiBufferRow,
5825        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5826    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5827        let max_point = self.max_point();
5828        let mut cursor = self.cursor::<Point, Point>();
5829        cursor.seek(&Point::new(end_row.0, 0));
5830        iter::from_fn(move || {
5831            let mut region = cursor.region()?;
5832            while !buffer_filter(&region.excerpt.buffer) {
5833                cursor.prev();
5834                region = cursor.region()?;
5835            }
5836
5837            let buffer_start_row = region.buffer_range.start.row;
5838            let buffer_end_row = if region.is_main_buffer
5839                && (region.has_trailing_newline || region.range.end == max_point)
5840            {
5841                region.buffer_range.end.row + 1
5842            } else {
5843                region.buffer_range.end.row
5844            };
5845
5846            let overshoot = end_row.0 - region.range.start.row;
5847            let buffer_end_row =
5848                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5849
5850            let line_indents = region
5851                .buffer
5852                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5853            cursor.prev();
5854            Some(line_indents.map(move |(buffer_row, indent)| {
5855                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5856                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5857            }))
5858        })
5859        .flatten()
5860    }
5861
5862    pub async fn enclosing_indent(
5863        &self,
5864        mut target_row: MultiBufferRow,
5865    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5866        let max_row = MultiBufferRow(self.max_point().row);
5867        if target_row >= max_row {
5868            return None;
5869        }
5870
5871        let mut target_indent = self.line_indent_for_row(target_row);
5872
5873        // If the current row is at the start of an indented block, we want to return this
5874        // block as the enclosing indent.
5875        if !target_indent.is_line_empty() && target_row < max_row {
5876            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5877            if !next_line_indent.is_line_empty()
5878                && target_indent.raw_len() < next_line_indent.raw_len()
5879            {
5880                target_indent = next_line_indent;
5881                target_row.0 += 1;
5882            }
5883        }
5884
5885        const SEARCH_ROW_LIMIT: u32 = 25000;
5886        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5887        const YIELD_INTERVAL: u32 = 100;
5888
5889        let mut accessed_row_counter = 0;
5890
5891        // If there is a blank line at the current row, search for the next non indented lines
5892        if target_indent.is_line_empty() {
5893            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5894            let end =
5895                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5896
5897            let mut non_empty_line_above = None;
5898            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5899                if row < start {
5900                    break;
5901                }
5902                accessed_row_counter += 1;
5903                if accessed_row_counter == YIELD_INTERVAL {
5904                    accessed_row_counter = 0;
5905                    yield_now().await;
5906                }
5907                if !indent.is_line_empty() {
5908                    non_empty_line_above = Some((row, indent));
5909                    break;
5910                }
5911            }
5912
5913            let mut non_empty_line_below = None;
5914            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5915                if row > end {
5916                    break;
5917                }
5918                accessed_row_counter += 1;
5919                if accessed_row_counter == YIELD_INTERVAL {
5920                    accessed_row_counter = 0;
5921                    yield_now().await;
5922                }
5923                if !indent.is_line_empty() {
5924                    non_empty_line_below = Some((row, indent));
5925                    break;
5926                }
5927            }
5928
5929            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5930                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5931                    if above_indent.raw_len() >= below_indent.raw_len() {
5932                        (above_row, above_indent)
5933                    } else {
5934                        (below_row, below_indent)
5935                    }
5936                }
5937                (Some(above), None) => above,
5938                (None, Some(below)) => below,
5939                _ => return None,
5940            };
5941
5942            target_indent = indent;
5943            target_row = row;
5944        }
5945
5946        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5947        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5948
5949        let mut start_indent = None;
5950        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5951            if row < start {
5952                break;
5953            }
5954            accessed_row_counter += 1;
5955            if accessed_row_counter == YIELD_INTERVAL {
5956                accessed_row_counter = 0;
5957                yield_now().await;
5958            }
5959            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5960                start_indent = Some((row, indent));
5961                break;
5962            }
5963        }
5964        let (start_row, start_indent_size) = start_indent?;
5965
5966        let mut end_indent = (end, None);
5967        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5968            if row > end {
5969                break;
5970            }
5971            accessed_row_counter += 1;
5972            if accessed_row_counter == YIELD_INTERVAL {
5973                accessed_row_counter = 0;
5974                yield_now().await;
5975            }
5976            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5977                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5978                break;
5979            }
5980        }
5981        let (end_row, end_indent_size) = end_indent;
5982
5983        let indent = if let Some(end_indent_size) = end_indent_size {
5984            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5985                start_indent_size
5986            } else {
5987                end_indent_size
5988            }
5989        } else {
5990            start_indent_size
5991        };
5992
5993        Some((start_row..end_row, indent))
5994    }
5995
5996    pub fn indent_guides_in_range<T: ToPoint>(
5997        &self,
5998        range: Range<T>,
5999        ignore_disabled_for_language: bool,
6000        cx: &App,
6001    ) -> impl Iterator<Item = IndentGuide> {
6002        let range = range.start.to_point(self)..range.end.to_point(self);
6003        let start_row = MultiBufferRow(range.start.row);
6004        let end_row = MultiBufferRow(range.end.row);
6005
6006        let mut row_indents = self.line_indents(start_row, |buffer| {
6007            let settings =
6008                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6009            settings.indent_guides.enabled || ignore_disabled_for_language
6010        });
6011
6012        let mut result = Vec::new();
6013        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6014
6015        let mut prev_settings = None;
6016        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6017            if first_row > end_row {
6018                break;
6019            }
6020            let current_depth = indent_stack.len() as u32;
6021
6022            // Avoid retrieving the language settings repeatedly for every buffer row.
6023            if let Some((prev_buffer_id, _)) = &prev_settings
6024                && prev_buffer_id != &buffer.remote_id()
6025            {
6026                prev_settings.take();
6027            }
6028            let settings = &prev_settings
6029                .get_or_insert_with(|| {
6030                    (
6031                        buffer.remote_id(),
6032                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6033                    )
6034                })
6035                .1;
6036            let tab_size = settings.tab_size.get();
6037
6038            // When encountering empty, continue until found useful line indent
6039            // then add to the indent stack with the depth found
6040            let mut found_indent = false;
6041            let mut last_row = first_row;
6042            if line_indent.is_line_blank() {
6043                while !found_indent {
6044                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6045                        break;
6046                    };
6047                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6048                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6049                        break;
6050                    }
6051
6052                    if new_line_indent.is_line_blank() {
6053                        continue;
6054                    }
6055                    last_row = target_row.min(end_row);
6056                    line_indent = new_line_indent;
6057                    found_indent = true;
6058                    break;
6059                }
6060            } else {
6061                found_indent = true
6062            }
6063
6064            let depth = if found_indent {
6065                line_indent.len(tab_size) / tab_size
6066            } else {
6067                0
6068            };
6069
6070            match depth.cmp(&current_depth) {
6071                cmp::Ordering::Less => {
6072                    for _ in 0..(current_depth - depth) {
6073                        let mut indent = indent_stack.pop().unwrap();
6074                        if last_row != first_row {
6075                            // In this case, we landed on an empty row, had to seek forward,
6076                            // and discovered that the indent we where on is ending.
6077                            // This means that the last display row must
6078                            // be on line that ends this indent range, so we
6079                            // should display the range up to the first non-empty line
6080                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6081                        }
6082
6083                        result.push(indent)
6084                    }
6085                }
6086                cmp::Ordering::Greater => {
6087                    for next_depth in current_depth..depth {
6088                        indent_stack.push(IndentGuide {
6089                            buffer_id: buffer.remote_id(),
6090                            start_row: first_row,
6091                            end_row: last_row,
6092                            depth: next_depth,
6093                            tab_size,
6094                            settings: settings.indent_guides.clone(),
6095                        });
6096                    }
6097                }
6098                _ => {}
6099            }
6100
6101            for indent in indent_stack.iter_mut() {
6102                indent.end_row = last_row;
6103            }
6104        }
6105
6106        result.extend(indent_stack);
6107        result.into_iter()
6108    }
6109
6110    pub fn trailing_excerpt_update_count(&self) -> usize {
6111        self.trailing_excerpt_update_count
6112    }
6113
6114    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6115        self.point_to_buffer_offset(point)
6116            .and_then(|(buffer, _)| buffer.file())
6117    }
6118
6119    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6120        self.point_to_buffer_offset(offset)
6121            .and_then(|(buffer, offset)| buffer.language_at(offset))
6122    }
6123
6124    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6125        self.excerpts
6126            .first()
6127            .map(|excerpt| &excerpt.buffer)
6128            .map(|buffer| {
6129                language_settings(
6130                    buffer.language().map(|language| language.name()),
6131                    buffer.file(),
6132                    cx,
6133                )
6134            })
6135            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6136    }
6137
6138    pub fn language_settings_at<'a, T: ToOffset>(
6139        &'a self,
6140        point: T,
6141        cx: &'a App,
6142    ) -> Cow<'a, LanguageSettings> {
6143        let mut language = None;
6144        let mut file = None;
6145        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6146            language = buffer.language_at(offset);
6147            file = buffer.file();
6148        }
6149        language_settings(language.map(|l| l.name()), file, cx)
6150    }
6151
6152    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6153        self.point_to_buffer_offset(point)
6154            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6155    }
6156
6157    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6158        self.point_to_buffer_offset(point)
6159            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6160            .unwrap_or_default()
6161    }
6162
6163    pub fn language_indent_size_at<T: ToOffset>(
6164        &self,
6165        position: T,
6166        cx: &App,
6167    ) -> Option<IndentSize> {
6168        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6169        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6170    }
6171
6172    pub fn is_dirty(&self) -> bool {
6173        self.is_dirty
6174    }
6175
6176    pub fn has_deleted_file(&self) -> bool {
6177        self.has_deleted_file
6178    }
6179
6180    pub fn has_conflict(&self) -> bool {
6181        self.has_conflict
6182    }
6183
6184    pub fn has_diagnostics(&self) -> bool {
6185        self.excerpts
6186            .iter()
6187            .any(|excerpt| excerpt.buffer.has_diagnostics())
6188    }
6189
6190    pub fn diagnostic_group(
6191        &self,
6192        buffer_id: BufferId,
6193        group_id: usize,
6194    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6195        self.lift_buffer_metadata::<Point, _, _>(
6196            Point::zero()..self.max_point(),
6197            move |buffer, range| {
6198                if buffer.remote_id() != buffer_id {
6199                    return None;
6200                };
6201                Some(
6202                    buffer
6203                        .diagnostics_in_range(range, false)
6204                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6205                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6206                )
6207            },
6208        )
6209        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6210    }
6211
6212    pub fn diagnostics_in_range<'a, MBD>(
6213        &'a self,
6214        range: Range<MBD>,
6215    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6216    where
6217        MBD::TextDimension: 'a
6218            + text::ToOffset
6219            + text::FromAnchor
6220            + Sub<Output = MBD::TextDimension>
6221            + fmt::Debug
6222            + ops::Add<Output = MBD::TextDimension>
6223            + ops::AddAssign
6224            + Ord,
6225        MBD: MultiBufferDimension
6226            + Ord
6227            + Sub<Output = MBD::TextDimension>
6228            + ops::Add<MBD::TextDimension, Output = MBD>
6229            + ops::AddAssign<MBD::TextDimension>
6230            + 'a,
6231    {
6232        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6233            Some(
6234                buffer
6235                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6236                    .map(|entry| (entry.range, entry.diagnostic)),
6237            )
6238        })
6239        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6240    }
6241
6242    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6243        &'a self,
6244        range: Range<MBD>,
6245    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6246    where
6247        MBD: MultiBufferDimension
6248            + Ord
6249            + Sub<Output = MBD::TextDimension>
6250            + ops::Add<MBD::TextDimension, Output = MBD>
6251            + ops::AddAssign<MBD::TextDimension>,
6252        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6253            + ops::Add<Output = MBD::TextDimension>
6254            + text::ToOffset
6255            + text::FromAnchor
6256            + AddAssign<MBD::TextDimension>
6257            + Ord,
6258    {
6259        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6260            Some(
6261                buffer
6262                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6263                    .map(|entry| (entry.range, entry.diagnostic)),
6264            )
6265        })
6266        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6267    }
6268
6269    pub fn syntax_ancestor<T: ToOffset>(
6270        &self,
6271        range: Range<T>,
6272    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6273        let range = range.start.to_offset(self)..range.end.to_offset(self);
6274        let mut excerpt = self.excerpt_containing(range.clone())?;
6275        let node = excerpt
6276            .buffer()
6277            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6278        let node_range = node.byte_range();
6279        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6280        if !excerpt.contains_buffer_range(node_range.clone()) {
6281            return None;
6282        };
6283        Some((node, excerpt.map_range_from_buffer(node_range)))
6284    }
6285
6286    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6287        let (excerpt_id, _, buffer) = self.as_singleton()?;
6288        let outline = buffer.outline(theme);
6289        Some(Outline::new(
6290            outline
6291                .items
6292                .into_iter()
6293                .flat_map(|item| {
6294                    Some(OutlineItem {
6295                        depth: item.depth,
6296                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6297                        source_range_for_text: self
6298                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6299                        text: item.text,
6300                        highlight_ranges: item.highlight_ranges,
6301                        name_ranges: item.name_ranges,
6302                        body_range: item.body_range.and_then(|body_range| {
6303                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6304                        }),
6305                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6306                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6307                        }),
6308                    })
6309                })
6310                .collect(),
6311        ))
6312    }
6313
6314    pub fn symbols_containing<T: ToOffset>(
6315        &self,
6316        offset: T,
6317        theme: Option<&SyntaxTheme>,
6318    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6319        let anchor = self.anchor_before(offset);
6320        let excerpt @ &Excerpt {
6321            id: excerpt_id,
6322            buffer_id,
6323            ref buffer,
6324            ..
6325        } = self.excerpt(anchor.excerpt_id)?;
6326        if cfg!(debug_assertions) {
6327            match anchor.text_anchor.buffer_id {
6328                // we clearly are hitting this according to sentry, but in what situations can this occur?
6329                Some(anchor_buffer_id) => {
6330                    assert_eq!(
6331                        anchor_buffer_id, buffer_id,
6332                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6333                    )
6334                }
6335                None => assert!(anchor.is_max()),
6336            }
6337        };
6338        Some((
6339            buffer_id,
6340            buffer
6341                .symbols_containing(anchor.text_anchor, theme)
6342                .into_iter()
6343                .flat_map(|item| {
6344                    Some(OutlineItem {
6345                        depth: item.depth,
6346                        source_range_for_text: Anchor::range_in_buffer(
6347                            excerpt_id,
6348                            item.source_range_for_text,
6349                        ),
6350                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6351                        text: item.text,
6352                        highlight_ranges: item.highlight_ranges,
6353                        name_ranges: item.name_ranges,
6354                        body_range: item
6355                            .body_range
6356                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6357                        annotation_range: item
6358                            .annotation_range
6359                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6360                    })
6361                })
6362                .collect(),
6363        ))
6364    }
6365
6366    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6367        if id == ExcerptId::min() {
6368            Locator::min_ref()
6369        } else if id == ExcerptId::max() {
6370            Locator::max_ref()
6371        } else {
6372            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6373            if let Some(entry) = item
6374                && entry.id == id
6375            {
6376                return &entry.locator;
6377            }
6378            panic!("invalid excerpt id {id:?}")
6379        }
6380    }
6381
6382    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6383    fn excerpt_locators_for_ids(
6384        &self,
6385        ids: impl IntoIterator<Item = ExcerptId>,
6386    ) -> SmallVec<[Locator; 1]> {
6387        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6388        sorted_ids.sort_unstable();
6389        sorted_ids.dedup();
6390        let mut locators = SmallVec::new();
6391
6392        while sorted_ids.last() == Some(&ExcerptId::max()) {
6393            sorted_ids.pop();
6394            locators.push(Locator::max());
6395        }
6396
6397        let mut sorted_ids = sorted_ids.into_iter().peekable();
6398        locators.extend(
6399            sorted_ids
6400                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6401                .map(|_| Locator::min()),
6402        );
6403
6404        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6405        for id in sorted_ids {
6406            if cursor.seek_forward(&id, Bias::Left) {
6407                locators.push(cursor.item().unwrap().locator.clone());
6408            } else {
6409                panic!("invalid excerpt id {:?}", id);
6410            }
6411        }
6412
6413        locators.sort_unstable();
6414        locators
6415    }
6416
6417    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6418        Some(self.excerpt(excerpt_id)?.buffer_id)
6419    }
6420
6421    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6422        Some(&self.excerpt(excerpt_id)?.buffer)
6423    }
6424
6425    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6426        let mut cursor = self
6427            .excerpts
6428            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6429        let locator = self.excerpt_locator_for_id(excerpt_id);
6430        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6431        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6432            sought_exact = true;
6433            cursor.prev();
6434        } else if excerpt_id == ExcerptId::min() {
6435            sought_exact = true;
6436        }
6437        if sought_exact {
6438            let start = cursor.start().1;
6439            let end = cursor.end().1;
6440            let mut diff_transforms = self
6441                .diff_transforms
6442                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6443            diff_transforms.seek(&start, Bias::Left);
6444            let overshoot = start - diff_transforms.start().0;
6445            let start = diff_transforms.start().1 + overshoot;
6446            diff_transforms.seek(&end, Bias::Right);
6447            let overshoot = end - diff_transforms.start().0;
6448            let end = diff_transforms.start().1 + overshoot;
6449            Some(start.0..end.0)
6450        } else {
6451            None
6452        }
6453    }
6454
6455    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6456    /// to have the same excerpt id as the one passed in, with the exception of
6457    /// `ExcerptId::max()`.
6458    ///
6459    /// Callers of this function should generally use the resulting excerpt's `id` field
6460    /// afterwards.
6461    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6462        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6463        let locator = self.excerpt_locator_for_id(excerpt_id);
6464        cursor.seek(&Some(locator), Bias::Left);
6465        if let Some(excerpt) = cursor.item()
6466            && excerpt.id == excerpt_id
6467        {
6468            return Some(excerpt);
6469        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6470            cursor.prev();
6471            return cursor.item();
6472        }
6473        None
6474    }
6475
6476    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6477    pub fn excerpt_containing<T: ToOffset>(
6478        &self,
6479        range: Range<T>,
6480    ) -> Option<MultiBufferExcerpt<'_>> {
6481        let range = range.start.to_offset(self)..range.end.to_offset(self);
6482        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6483        cursor.seek(&range.start);
6484
6485        let start_excerpt = cursor.excerpt()?;
6486        if range.end != range.start {
6487            cursor.seek_forward(&range.end);
6488            if cursor.excerpt()?.id != start_excerpt.id {
6489                return None;
6490            }
6491        }
6492
6493        cursor.seek_to_start_of_current_excerpt();
6494        let region = cursor.region()?;
6495        let offset = region.range.start;
6496        let buffer_offset = start_excerpt.buffer_start_offset();
6497        let excerpt_offset = *cursor.excerpts.start();
6498        Some(MultiBufferExcerpt {
6499            diff_transforms: cursor.diff_transforms,
6500            excerpt: start_excerpt,
6501            offset,
6502            buffer_offset,
6503            excerpt_offset,
6504        })
6505    }
6506
6507    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6508        if let Some(id) = anchor.text_anchor.buffer_id {
6509            return Some(id);
6510        }
6511        let excerpt = self.excerpt_containing(anchor..anchor)?;
6512        Some(excerpt.buffer_id())
6513    }
6514
6515    pub fn selections_in_range<'a>(
6516        &'a self,
6517        range: &'a Range<Anchor>,
6518        include_local: bool,
6519    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6520        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6521        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6522        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6523        cursor.seek(start_locator, Bias::Left);
6524        cursor
6525            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6526            .flat_map(move |excerpt| {
6527                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6528                if excerpt.id == range.start.excerpt_id {
6529                    query_range.start = range.start.text_anchor;
6530                }
6531                if excerpt.id == range.end.excerpt_id {
6532                    query_range.end = range.end.text_anchor;
6533                }
6534
6535                excerpt
6536                    .buffer
6537                    .selections_in_range(query_range, include_local)
6538                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6539                        selections.map(move |selection| {
6540                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6541                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6542                            if range.start.cmp(&start, self).is_gt() {
6543                                start = range.start;
6544                            }
6545                            if range.end.cmp(&end, self).is_lt() {
6546                                end = range.end;
6547                            }
6548
6549                            (
6550                                replica_id,
6551                                line_mode,
6552                                cursor_shape,
6553                                Selection {
6554                                    id: selection.id,
6555                                    start,
6556                                    end,
6557                                    reversed: selection.reversed,
6558                                    goal: selection.goal,
6559                                },
6560                            )
6561                        })
6562                    })
6563            })
6564    }
6565
6566    pub fn show_headers(&self) -> bool {
6567        self.show_headers
6568    }
6569
6570    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6571        self.diffs.get(&buffer_id)
6572    }
6573
6574    /// Visually annotates a position or range with the `Debug` representation of a value. The
6575    /// callsite of this function is used as a key - previous annotations will be removed.
6576    #[cfg(debug_assertions)]
6577    #[track_caller]
6578    pub fn debug<V, R>(&self, ranges: &R, value: V)
6579    where
6580        R: debug::ToMultiBufferDebugRanges,
6581        V: std::fmt::Debug,
6582    {
6583        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6584    }
6585
6586    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6587    /// debug annotations with the same key will be removed. The key is also used to determine the
6588    /// annotation's color.
6589    #[cfg(debug_assertions)]
6590    #[track_caller]
6591    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6592    where
6593        K: std::hash::Hash + 'static,
6594        R: debug::ToMultiBufferDebugRanges,
6595        V: std::fmt::Debug,
6596    {
6597        let text_ranges = ranges
6598            .to_multi_buffer_debug_ranges(self)
6599            .into_iter()
6600            .flat_map(|range| {
6601                self.range_to_buffer_ranges(range).into_iter().map(
6602                    |(buffer, range, _excerpt_id)| {
6603                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6604                    },
6605                )
6606            })
6607            .collect();
6608        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6609            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6610        });
6611    }
6612}
6613
6614#[cfg(any(test, feature = "test-support"))]
6615impl MultiBufferSnapshot {
6616    pub fn random_byte_range(
6617        &self,
6618        start_offset: MultiBufferOffset,
6619        rng: &mut impl rand::Rng,
6620    ) -> Range<MultiBufferOffset> {
6621        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6622        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6623        start..end
6624    }
6625
6626    #[cfg(any(test, feature = "test-support"))]
6627    fn check_invariants(&self) {
6628        let excerpts = self.excerpts.items(());
6629        let excerpt_ids = self.excerpt_ids.items(());
6630
6631        assert!(
6632            self.excerpts.is_empty() || !self.diff_transforms.is_empty(),
6633            "must be at least one diff transform if excerpts exist"
6634        );
6635
6636        for (ix, excerpt) in excerpts.iter().enumerate() {
6637            if ix == 0 {
6638                if excerpt.locator <= Locator::min() {
6639                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6640                }
6641            } else if excerpt.locator <= excerpts[ix - 1].locator {
6642                panic!("excerpts are out-of-order: {:?}", excerpts);
6643            }
6644        }
6645
6646        for (ix, entry) in excerpt_ids.iter().enumerate() {
6647            if ix == 0 {
6648                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6649                    panic!("invalid first excerpt id {:?}", entry.id);
6650                }
6651            } else if entry.id <= excerpt_ids[ix - 1].id {
6652                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6653            }
6654        }
6655
6656        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6657            panic!(
6658                "incorrect input summary. expected {:#?}, got {:#?}. transforms: {:#?}",
6659                self.excerpts.summary().text,
6660                self.diff_transforms.summary().input,
6661                self.diff_transforms.items(()),
6662            );
6663        }
6664
6665        for (left, right) in self.diff_transforms.iter().tuple_windows() {
6666            use sum_tree::Item;
6667
6668            if left.is_buffer_content()
6669                && left.summary(()).input.len == MultiBufferOffset(0)
6670                && !self.is_empty()
6671            {
6672                panic!("empty buffer content transform in non-empty snapshot");
6673            }
6674            assert!(
6675                left.clone().merged_with(right).is_none(),
6676                "two consecutive diff transforms could have been merged, but weren't"
6677            );
6678        }
6679    }
6680}
6681
6682impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6683where
6684    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6685    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6686{
6687    fn seek(&mut self, position: &MBD) {
6688        let position = OutputDimension(*position);
6689        self.cached_region.take();
6690        self.diff_transforms.seek(&position, Bias::Right);
6691        if self.diff_transforms.item().is_none()
6692            && self.diff_transforms.start().output_dimension == position
6693        {
6694            self.diff_transforms.prev();
6695        }
6696
6697        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6698        if let Some(item) = self.diff_transforms.item()
6699            && item.is_buffer_content()
6700        {
6701            let overshoot = position - self.diff_transforms.start().output_dimension;
6702            excerpt_position += overshoot;
6703        }
6704
6705        self.excerpts.seek(&excerpt_position, Bias::Right);
6706        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6707            self.excerpts.prev();
6708        }
6709    }
6710
6711    fn seek_forward(&mut self, position: &MBD) {
6712        let position = OutputDimension(*position);
6713        self.cached_region.take();
6714        self.diff_transforms.seek_forward(&position, Bias::Right);
6715        if self.diff_transforms.item().is_none()
6716            && self.diff_transforms.start().output_dimension == position
6717        {
6718            self.diff_transforms.prev();
6719        }
6720
6721        let overshoot = position - self.diff_transforms.start().output_dimension;
6722        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6723        if let Some(item) = self.diff_transforms.item()
6724            && item.is_buffer_content()
6725        {
6726            excerpt_position += overshoot;
6727        }
6728
6729        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6730        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6731            self.excerpts.prev();
6732        }
6733    }
6734
6735    fn next_excerpt(&mut self) {
6736        self.excerpts.next();
6737        self.seek_to_start_of_current_excerpt();
6738    }
6739
6740    fn prev_excerpt(&mut self) {
6741        self.excerpts.prev();
6742        self.seek_to_start_of_current_excerpt();
6743    }
6744
6745    fn seek_to_start_of_current_excerpt(&mut self) {
6746        self.cached_region.take();
6747        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6748        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6749            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6750            && self.diff_transforms.next_item().is_some()
6751        {
6752            self.diff_transforms.next();
6753        }
6754    }
6755
6756    fn next(&mut self) {
6757        self.cached_region.take();
6758        match self
6759            .diff_transforms
6760            .end()
6761            .excerpt_dimension
6762            .cmp(&self.excerpts.end())
6763        {
6764            cmp::Ordering::Less => {
6765                self.diff_transforms.next();
6766            }
6767            cmp::Ordering::Greater => {
6768                self.excerpts.next();
6769            }
6770            cmp::Ordering::Equal => {
6771                self.diff_transforms.next();
6772                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6773                    || self.diff_transforms.item().is_none()
6774                {
6775                    self.excerpts.next();
6776                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6777                    self.diff_transforms.item()
6778                    && self
6779                        .excerpts
6780                        .item()
6781                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6782                {
6783                    self.excerpts.next();
6784                }
6785            }
6786        }
6787    }
6788
6789    fn prev(&mut self) {
6790        self.cached_region.take();
6791        match self
6792            .diff_transforms
6793            .start()
6794            .excerpt_dimension
6795            .cmp(self.excerpts.start())
6796        {
6797            cmp::Ordering::Less => self.excerpts.prev(),
6798            cmp::Ordering::Greater => self.diff_transforms.prev(),
6799            cmp::Ordering::Equal => {
6800                self.diff_transforms.prev();
6801                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6802                    || self.diff_transforms.item().is_none()
6803                {
6804                    self.excerpts.prev();
6805                }
6806            }
6807        }
6808    }
6809
6810    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6811        if self.cached_region.is_none() {
6812            self.cached_region = self.build_region();
6813        }
6814        self.cached_region.clone()
6815    }
6816
6817    fn is_at_start_of_excerpt(&mut self) -> bool {
6818        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6819            return false;
6820        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6821            return true;
6822        }
6823
6824        self.diff_transforms.prev();
6825        let prev_transform = self.diff_transforms.item();
6826        self.diff_transforms.next();
6827
6828        prev_transform.is_none_or(|prev_transform| prev_transform.is_buffer_content())
6829    }
6830
6831    fn is_at_end_of_excerpt(&mut self) -> bool {
6832        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6833            return false;
6834        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6835            || self.diff_transforms.item().is_none()
6836        {
6837            return true;
6838        }
6839
6840        let next_transform = self.diff_transforms.next_item();
6841        next_transform.is_none_or(|next_transform| match next_transform {
6842            DiffTransform::Unmodified { .. }
6843            | DiffTransform::InsertedHunk { .. }
6844            | DiffTransform::FilteredInsertedHunk { .. } => true,
6845            DiffTransform::DeletedHunk { hunk_info, .. } => self
6846                .excerpts
6847                .item()
6848                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6849        })
6850    }
6851
6852    fn main_buffer_position(&self) -> Option<BD> {
6853        let excerpt = self.excerpts.item()?;
6854        let buffer = &excerpt.buffer;
6855        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6856        let mut buffer_start = buffer_context_start;
6857        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6858        buffer_start += overshoot;
6859        Some(buffer_start)
6860    }
6861
6862    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6863        let excerpt = self.excerpts.item()?;
6864        match self.diff_transforms.item()? {
6865            DiffTransform::DeletedHunk {
6866                buffer_id,
6867                has_trailing_newline,
6868                hunk_info,
6869                ..
6870            } => {
6871                let diff = self.snapshot.diffs.get(buffer_id)?;
6872                let buffer = diff.base_text();
6873                let mut rope_cursor = buffer.as_rope().cursor(0);
6874                let buffer_start = rope_cursor.summary::<BD>(hunk_info.base_text_byte_range.start);
6875                let buffer_range_len =
6876                    rope_cursor.summary::<BD>(hunk_info.base_text_byte_range.end);
6877                let mut buffer_end = buffer_start;
6878                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6879                let start = self.diff_transforms.start().output_dimension.0;
6880                let end = self.diff_transforms.end().output_dimension.0;
6881
6882                Some(MultiBufferRegion {
6883                    buffer,
6884                    excerpt,
6885                    has_trailing_newline: *has_trailing_newline,
6886                    is_main_buffer: false,
6887                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6888                        hunk_info.hunk_secondary_status,
6889                    )),
6890                    buffer_range: buffer_start..buffer_end,
6891                    range: start..end,
6892                    diff_base_byte_range: Some(hunk_info.base_text_byte_range.clone()),
6893                })
6894            }
6895            transform @ (DiffTransform::Unmodified { .. }
6896            | DiffTransform::InsertedHunk { .. }
6897            | DiffTransform::FilteredInsertedHunk { .. }) => {
6898                let mut diff_hunk_status = transform
6899                    .hunk_info()
6900                    .map(|hunk_info| DiffHunkStatus::added(hunk_info.hunk_secondary_status));
6901
6902                let diff_base_byte_range = transform
6903                    .hunk_info()
6904                    .map(|hunk_info| hunk_info.base_text_byte_range);
6905
6906                let buffer = &excerpt.buffer;
6907                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6908
6909                let mut start = self.diff_transforms.start().output_dimension.0;
6910                let mut buffer_start = buffer_context_start;
6911                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6912                    let overshoot =
6913                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6914                    start += overshoot;
6915                } else {
6916                    let overshoot =
6917                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6918                    buffer_start += overshoot;
6919                }
6920
6921                let mut end;
6922                let mut buffer_end;
6923                let has_trailing_newline;
6924                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6925                    let overshoot =
6926                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6927                    end = self.diff_transforms.end().output_dimension.0;
6928                    buffer_end = buffer_context_start;
6929                    buffer_end += overshoot;
6930                    has_trailing_newline = false;
6931                } else {
6932                    let overshoot =
6933                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6934                    end = self.diff_transforms.start().output_dimension.0;
6935                    end += overshoot;
6936                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6937                    has_trailing_newline = excerpt.has_trailing_newline;
6938                };
6939
6940                if matches!(transform, DiffTransform::FilteredInsertedHunk { .. }) {
6941                    buffer_end = buffer_start;
6942                    end = start;
6943                    diff_hunk_status = None;
6944                }
6945
6946                Some(MultiBufferRegion {
6947                    buffer,
6948                    excerpt,
6949                    has_trailing_newline,
6950                    is_main_buffer: true,
6951                    diff_hunk_status,
6952                    diff_base_byte_range,
6953                    buffer_range: buffer_start..buffer_end,
6954                    range: start..end,
6955                })
6956            }
6957        }
6958    }
6959
6960    fn excerpt(&self) -> Option<&'a Excerpt> {
6961        self.excerpts.item()
6962    }
6963}
6964
6965impl Excerpt {
6966    fn new(
6967        id: ExcerptId,
6968        locator: Locator,
6969        buffer_id: BufferId,
6970        buffer: BufferSnapshot,
6971        range: ExcerptRange<text::Anchor>,
6972        has_trailing_newline: bool,
6973    ) -> Self {
6974        Excerpt {
6975            id,
6976            locator,
6977            max_buffer_row: range.context.end.to_point(&buffer).row,
6978            text_summary: buffer
6979                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6980            buffer_id,
6981            buffer,
6982            range,
6983            has_trailing_newline,
6984        }
6985    }
6986
6987    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6988        let content_start = self.range.context.start.to_offset(&self.buffer);
6989        let chunks_start = content_start + range.start;
6990        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6991
6992        let has_footer = self.has_trailing_newline
6993            && range.start <= self.text_summary.len
6994            && range.end > self.text_summary.len;
6995
6996        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6997
6998        ExcerptChunks {
6999            excerpt_id: self.id,
7000            content_chunks,
7001            has_footer,
7002        }
7003    }
7004
7005    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7006        let content_start = self.range.context.start.to_offset(&self.buffer);
7007        let chunks_start = content_start + range.start;
7008        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7009        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7010        excerpt_chunks.has_footer = self.has_trailing_newline
7011            && range.start <= self.text_summary.len
7012            && range.end > self.text_summary.len;
7013    }
7014
7015    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7016        if text_anchor
7017            .cmp(&self.range.context.start, &self.buffer)
7018            .is_lt()
7019        {
7020            self.range.context.start
7021        } else if text_anchor
7022            .cmp(&self.range.context.end, &self.buffer)
7023            .is_gt()
7024        {
7025            self.range.context.end
7026        } else {
7027            text_anchor
7028        }
7029    }
7030
7031    fn contains(&self, anchor: &Anchor) -> bool {
7032        (anchor.text_anchor.buffer_id == None
7033            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7034            && self
7035                .range
7036                .context
7037                .start
7038                .cmp(&anchor.text_anchor, &self.buffer)
7039                .is_le()
7040            && self
7041                .range
7042                .context
7043                .end
7044                .cmp(&anchor.text_anchor, &self.buffer)
7045                .is_ge()
7046    }
7047
7048    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7049    fn buffer_start_offset(&self) -> BufferOffset {
7050        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7051    }
7052
7053    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7054    fn buffer_end_offset(&self) -> BufferOffset {
7055        self.buffer_start_offset() + self.text_summary.len
7056    }
7057}
7058
7059impl<'a> MultiBufferExcerpt<'a> {
7060    pub fn id(&self) -> ExcerptId {
7061        self.excerpt.id
7062    }
7063
7064    pub fn buffer_id(&self) -> BufferId {
7065        self.excerpt.buffer_id
7066    }
7067
7068    pub fn start_anchor(&self) -> Anchor {
7069        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7070    }
7071
7072    pub fn end_anchor(&self) -> Anchor {
7073        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7074    }
7075
7076    pub fn buffer(&self) -> &'a BufferSnapshot {
7077        &self.excerpt.buffer
7078    }
7079
7080    pub fn buffer_range(&self) -> Range<BufferOffset> {
7081        self.buffer_offset
7082            ..BufferOffset(
7083                self.excerpt
7084                    .range
7085                    .context
7086                    .end
7087                    .to_offset(&self.excerpt.buffer.text),
7088            )
7089    }
7090
7091    pub fn start_offset(&self) -> MultiBufferOffset {
7092        self.offset
7093    }
7094
7095    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7096    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7097        self.map_range_to_buffer(offset..offset).start
7098    }
7099
7100    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7101    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7102        self.diff_transforms
7103            .seek(&OutputDimension(range.start), Bias::Right);
7104        let start = self.map_offset_to_buffer_internal(range.start);
7105        let end = if range.end > range.start {
7106            self.diff_transforms
7107                .seek_forward(&OutputDimension(range.end), Bias::Right);
7108            self.map_offset_to_buffer_internal(range.end)
7109        } else {
7110            start
7111        };
7112        start..end
7113    }
7114
7115    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7116        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7117        if self
7118            .diff_transforms
7119            .item()
7120            .is_some_and(|t| t.is_buffer_content())
7121        {
7122            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7123        };
7124        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7125        self.buffer_offset + offset_in_excerpt
7126    }
7127
7128    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7129    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7130        self.map_range_from_buffer(buffer_offset..buffer_offset)
7131            .start
7132    }
7133
7134    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7135    pub fn map_range_from_buffer(
7136        &mut self,
7137        buffer_range: Range<BufferOffset>,
7138    ) -> Range<MultiBufferOffset> {
7139        if buffer_range.start < self.buffer_offset {
7140            log::warn!(
7141                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7142            );
7143            return self.offset..self.offset;
7144        }
7145        let overshoot = buffer_range.start - self.buffer_offset;
7146        let excerpt_offset = self.excerpt_offset + overshoot;
7147        let excerpt_seek_dim = excerpt_offset;
7148        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7149        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7150            log::warn!(
7151                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7152            );
7153            return self.offset..self.offset;
7154        }
7155        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7156        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7157
7158        let end = if buffer_range.start < buffer_range.end {
7159            let overshoot = buffer_range.end - self.buffer_offset;
7160            let excerpt_offset = self.excerpt_offset + overshoot;
7161            let excerpt_seek_dim = excerpt_offset;
7162            self.diff_transforms
7163                .seek_forward(&excerpt_seek_dim, Bias::Right);
7164            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7165            // todo(lw): Clamp end to the excerpt boundaries
7166            self.diff_transforms.start().output_dimension.0 + overshoot
7167        } else {
7168            start
7169        };
7170
7171        start..end
7172    }
7173
7174    /// Returns true if the entirety of the given range is in the buffer's excerpt
7175    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7176        range.start >= self.excerpt.buffer_start_offset()
7177            && range.end <= self.excerpt.buffer_end_offset()
7178    }
7179
7180    pub fn max_buffer_row(&self) -> u32 {
7181        self.excerpt.max_buffer_row
7182    }
7183}
7184
7185impl ExcerptId {
7186    pub fn min() -> Self {
7187        Self(0)
7188    }
7189
7190    pub fn max() -> Self {
7191        Self(u32::MAX)
7192    }
7193
7194    pub fn to_proto(self) -> u64 {
7195        self.0 as _
7196    }
7197
7198    pub fn from_proto(proto: u64) -> Self {
7199        Self(proto as _)
7200    }
7201
7202    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7203        let a = snapshot.excerpt_locator_for_id(*self);
7204        let b = snapshot.excerpt_locator_for_id(*other);
7205        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7206    }
7207}
7208
7209impl From<ExcerptId> for usize {
7210    fn from(val: ExcerptId) -> Self {
7211        val.0 as usize
7212    }
7213}
7214
7215impl fmt::Debug for Excerpt {
7216    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7217        f.debug_struct("Excerpt")
7218            .field("id", &self.id)
7219            .field("locator", &self.locator)
7220            .field("buffer_id", &self.buffer_id)
7221            .field("range", &self.range)
7222            .field("text_summary", &self.text_summary)
7223            .field("has_trailing_newline", &self.has_trailing_newline)
7224            .finish()
7225    }
7226}
7227
7228impl sum_tree::Item for Excerpt {
7229    type Summary = ExcerptSummary;
7230
7231    fn summary(&self, _cx: ()) -> Self::Summary {
7232        let mut text = self.text_summary;
7233        if self.has_trailing_newline {
7234            text += TextSummary::from("\n");
7235        }
7236        ExcerptSummary {
7237            excerpt_id: self.id,
7238            excerpt_locator: self.locator.clone(),
7239            widest_line_number: self.max_buffer_row,
7240            text: text.into(),
7241        }
7242    }
7243}
7244
7245impl sum_tree::Item for ExcerptIdMapping {
7246    type Summary = ExcerptId;
7247
7248    fn summary(&self, _cx: ()) -> Self::Summary {
7249        self.id
7250    }
7251}
7252
7253impl sum_tree::KeyedItem for ExcerptIdMapping {
7254    type Key = ExcerptId;
7255
7256    fn key(&self) -> Self::Key {
7257        self.id
7258    }
7259}
7260
7261impl DiffTransform {
7262    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7263        match self {
7264            DiffTransform::DeletedHunk { hunk_info, .. }
7265            | DiffTransform::InsertedHunk { hunk_info, .. }
7266            | DiffTransform::FilteredInsertedHunk { hunk_info, .. } => Some(hunk_info.clone()),
7267            DiffTransform::Unmodified { .. } => None,
7268        }
7269    }
7270
7271    fn is_buffer_content(&self) -> bool {
7272        match self {
7273            Self::Unmodified { .. }
7274            | Self::InsertedHunk { .. }
7275            | Self::FilteredInsertedHunk { .. } => true,
7276            Self::DeletedHunk { .. } => false,
7277        }
7278    }
7279}
7280
7281impl sum_tree::Item for DiffTransform {
7282    type Summary = DiffTransformSummary;
7283
7284    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7285        match self {
7286            DiffTransform::InsertedHunk { summary, .. }
7287            | DiffTransform::Unmodified { summary, .. } => DiffTransformSummary {
7288                input: *summary,
7289                output: *summary,
7290            },
7291            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7292                input: MBTextSummary::default(),
7293                output: summary.into(),
7294            },
7295            DiffTransform::FilteredInsertedHunk { summary, .. } => DiffTransformSummary {
7296                input: *summary,
7297                output: MBTextSummary::default(),
7298            },
7299        }
7300    }
7301}
7302
7303impl DiffTransformSummary {
7304    fn excerpt_len(&self) -> ExcerptOffset {
7305        ExcerptDimension(self.input.len)
7306    }
7307}
7308
7309impl sum_tree::ContextLessSummary for DiffTransformSummary {
7310    fn zero() -> Self {
7311        DiffTransformSummary {
7312            input: MBTextSummary::default(),
7313            output: MBTextSummary::default(),
7314        }
7315    }
7316
7317    fn add_summary(&mut self, other: &Self) {
7318        self.input += other.input;
7319        self.output += other.output;
7320    }
7321}
7322
7323impl sum_tree::ContextLessSummary for ExcerptId {
7324    fn zero() -> Self {
7325        Self(0)
7326    }
7327
7328    fn add_summary(&mut self, summary: &Self) {
7329        *self = cmp::max(*self, *summary);
7330    }
7331}
7332
7333impl sum_tree::ContextLessSummary for ExcerptSummary {
7334    fn zero() -> Self {
7335        Self::default()
7336    }
7337
7338    fn add_summary(&mut self, summary: &Self) {
7339        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7340        self.excerpt_locator = summary.excerpt_locator.clone();
7341        self.text += summary.text;
7342        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7343    }
7344}
7345
7346impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7347    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7348        Ord::cmp(&Some(self), cursor_location)
7349    }
7350}
7351
7352impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7353    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7354        Ord::cmp(self, &cursor_location.excerpt_locator)
7355    }
7356}
7357
7358impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7359where
7360    MBD: MultiBufferDimension + Default,
7361{
7362    fn zero(_: ()) -> Self {
7363        ExcerptDimension(MBD::default())
7364    }
7365
7366    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7367        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7368    }
7369}
7370
7371impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7372    fn zero(_cx: ()) -> Self {
7373        Default::default()
7374    }
7375
7376    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7377        *self = Some(&summary.excerpt_locator);
7378    }
7379}
7380
7381impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7382    fn zero(_cx: ()) -> Self {
7383        Default::default()
7384    }
7385
7386    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7387        *self = Some(summary.excerpt_id);
7388    }
7389}
7390
7391#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7392struct OutputDimension<T>(T);
7393
7394impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7395    fn eq(&self, other: &T) -> bool {
7396        self.0 == *other
7397    }
7398}
7399
7400impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7401    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7402        self.0.partial_cmp(other)
7403    }
7404}
7405
7406impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7407where
7408    T: ops::Sub<U, Output = R>,
7409{
7410    type Output = R;
7411
7412    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7413        self.0 - other.0
7414    }
7415}
7416
7417impl<R, T, U> ops::Add<U> for OutputDimension<T>
7418where
7419    T: ops::Add<U, Output = R>,
7420{
7421    type Output = OutputDimension<R>;
7422
7423    fn add(self, other: U) -> Self::Output {
7424        OutputDimension(self.0 + other)
7425    }
7426}
7427
7428impl<T, U> AddAssign<U> for OutputDimension<T>
7429where
7430    T: AddAssign<U>,
7431{
7432    fn add_assign(&mut self, other: U) {
7433        self.0 += other;
7434    }
7435}
7436
7437impl<T, U> SubAssign<U> for OutputDimension<T>
7438where
7439    T: SubAssign<U>,
7440{
7441    fn sub_assign(&mut self, other: U) {
7442        self.0 -= other;
7443    }
7444}
7445
7446#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7447struct ExcerptDimension<T>(T);
7448
7449impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7450    fn eq(&self, other: &T) -> bool {
7451        self.0 == *other
7452    }
7453}
7454
7455impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7456    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7457        self.0.partial_cmp(other)
7458    }
7459}
7460
7461impl ExcerptOffset {
7462    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7463        self.0.saturating_sub(other.0)
7464    }
7465}
7466
7467impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7468where
7469    T: ops::Sub<U, Output = R>,
7470{
7471    type Output = R;
7472
7473    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7474        self.0 - other.0
7475    }
7476}
7477
7478impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7479where
7480    T: ops::Add<U, Output = R>,
7481{
7482    type Output = ExcerptDimension<R>;
7483
7484    fn add(self, other: U) -> Self::Output {
7485        ExcerptDimension(self.0 + other)
7486    }
7487}
7488
7489impl<T, U> AddAssign<U> for ExcerptDimension<T>
7490where
7491    T: AddAssign<U>,
7492{
7493    fn add_assign(&mut self, other: U) {
7494        self.0 += other;
7495    }
7496}
7497
7498impl<T, U> SubAssign<U> for ExcerptDimension<T>
7499where
7500    T: SubAssign<U>,
7501{
7502    fn sub_assign(&mut self, other: U) {
7503        self.0 -= other;
7504    }
7505}
7506
7507impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7508    fn zero(_: ()) -> Self {
7509        MultiBufferOffset::ZERO
7510    }
7511
7512    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7513        *self += summary.output.len;
7514    }
7515}
7516
7517impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7518    for ExcerptDimension<MBD>
7519where
7520    MBD: MultiBufferDimension + Ord,
7521{
7522    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7523        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7524    }
7525}
7526
7527impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7528    for ExcerptDimension<MBD>
7529where
7530    MBD: MultiBufferDimension + Ord,
7531{
7532    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7533        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7534    }
7535}
7536
7537impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7538    for ExcerptDimension<MBD>
7539{
7540    fn zero(_: ()) -> Self {
7541        ExcerptDimension(MBD::default())
7542    }
7543
7544    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7545        self.0.add_mb_text_summary(&summary.input)
7546    }
7547}
7548
7549impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7550    for OutputDimension<MBD>
7551where
7552    MBD: MultiBufferDimension + Ord,
7553{
7554    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7555        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7556    }
7557}
7558
7559impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7560    for OutputDimension<MBD>
7561{
7562    fn zero(_: ()) -> Self {
7563        OutputDimension(MBD::default())
7564    }
7565
7566    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7567        self.0.add_mb_text_summary(&summary.output)
7568    }
7569}
7570
7571impl MultiBufferRows<'_> {
7572    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7573        self.point = Point::new(row, 0);
7574        self.cursor.seek(&self.point);
7575    }
7576}
7577
7578impl Iterator for MultiBufferRows<'_> {
7579    type Item = RowInfo;
7580
7581    fn next(&mut self) -> Option<Self::Item> {
7582        if self.is_empty && self.point.row == 0 {
7583            self.point += Point::new(1, 0);
7584            return Some(RowInfo {
7585                buffer_id: None,
7586                buffer_row: Some(0),
7587                base_text_row: Some(BaseTextRow(0)),
7588                multibuffer_row: Some(MultiBufferRow(0)),
7589                diff_status: None,
7590                expand_info: None,
7591                wrapped_buffer_row: None,
7592            });
7593        }
7594
7595        let mut region = self.cursor.region()?;
7596        while self.point >= region.range.end {
7597            self.cursor.next();
7598            if let Some(next_region) = self.cursor.region() {
7599                region = next_region;
7600            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7601                let multibuffer_row = MultiBufferRow(self.point.row);
7602                let last_excerpt = self
7603                    .cursor
7604                    .excerpts
7605                    .item()
7606                    .or(self.cursor.excerpts.prev_item())?;
7607                let last_row = last_excerpt
7608                    .range
7609                    .context
7610                    .end
7611                    .to_point(&last_excerpt.buffer)
7612                    .row;
7613                // TODO(split-diff) perf
7614                let base_text_row = self
7615                    .cursor
7616                    .snapshot
7617                    .diffs
7618                    .get(&last_excerpt.buffer_id)
7619                    .map(|diff| diff.row_to_base_text_row(last_row, &last_excerpt.buffer))
7620                    .map(BaseTextRow);
7621
7622                let first_row = last_excerpt
7623                    .range
7624                    .context
7625                    .start
7626                    .to_point(&last_excerpt.buffer)
7627                    .row;
7628
7629                let expand_info = if self.is_singleton {
7630                    None
7631                } else {
7632                    let needs_expand_up = first_row == last_row
7633                        && (last_row > 0)
7634                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted())
7635                        && !(region.is_filtered()
7636                            && region
7637                                .diff_base_byte_range
7638                                .is_some_and(|range| !range.is_empty()));
7639                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7640
7641                    if needs_expand_up && needs_expand_down {
7642                        Some(ExpandExcerptDirection::UpAndDown)
7643                    } else if needs_expand_up {
7644                        Some(ExpandExcerptDirection::Up)
7645                    } else if needs_expand_down {
7646                        Some(ExpandExcerptDirection::Down)
7647                    } else {
7648                        None
7649                    }
7650                    .map(|direction| ExpandInfo {
7651                        direction,
7652                        excerpt_id: last_excerpt.id,
7653                    })
7654                };
7655                self.point += Point::new(1, 0);
7656                return Some(RowInfo {
7657                    buffer_id: Some(last_excerpt.buffer_id),
7658                    buffer_row: Some(last_row),
7659                    base_text_row,
7660                    multibuffer_row: Some(multibuffer_row),
7661                    diff_status: None,
7662                    wrapped_buffer_row: None,
7663                    expand_info,
7664                });
7665            } else {
7666                return None;
7667            };
7668        }
7669
7670        let overshoot = self.point - region.range.start;
7671        let buffer_point = region.buffer_range.start + overshoot;
7672        let diff_status = region
7673            .diff_hunk_status
7674            .filter(|_| self.point < region.range.end);
7675        let base_text_row = match diff_status {
7676            // TODO(split-diff) perf
7677            None => self
7678                .cursor
7679                .snapshot
7680                .diffs
7681                .get(&region.excerpt.buffer_id)
7682                .map(|diff| diff.row_to_base_text_row(buffer_point.row, &region.buffer))
7683                .map(BaseTextRow),
7684            Some(DiffHunkStatus {
7685                kind: DiffHunkStatusKind::Added,
7686                ..
7687            }) => None,
7688            Some(DiffHunkStatus {
7689                kind: DiffHunkStatusKind::Deleted,
7690                ..
7691            }) => Some(BaseTextRow(buffer_point.row)),
7692            Some(DiffHunkStatus {
7693                kind: DiffHunkStatusKind::Modified,
7694                ..
7695            }) => unreachable!(),
7696        };
7697        let expand_info = if self.is_singleton {
7698            None
7699        } else {
7700            let needs_expand_up = self.point.row == region.range.start.row
7701                && self.cursor.is_at_start_of_excerpt()
7702                && buffer_point.row > 0;
7703            let needs_expand_down = (region.excerpt.has_trailing_newline
7704                && self.point.row + 1 == region.range.end.row
7705                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7706                && self.cursor.is_at_end_of_excerpt()
7707                && buffer_point.row < region.buffer.max_point().row;
7708
7709            if needs_expand_up && needs_expand_down {
7710                Some(ExpandExcerptDirection::UpAndDown)
7711            } else if needs_expand_up {
7712                Some(ExpandExcerptDirection::Up)
7713            } else if needs_expand_down {
7714                Some(ExpandExcerptDirection::Down)
7715            } else {
7716                None
7717            }
7718            .map(|direction| ExpandInfo {
7719                direction,
7720                excerpt_id: region.excerpt.id,
7721            })
7722        };
7723
7724        let result = Some(RowInfo {
7725            buffer_id: Some(region.buffer.remote_id()),
7726            buffer_row: Some(buffer_point.row),
7727            base_text_row,
7728            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7729            diff_status,
7730            expand_info,
7731            wrapped_buffer_row: None,
7732        });
7733        self.point += Point::new(1, 0);
7734        result
7735    }
7736}
7737
7738impl<'a> MultiBufferChunks<'a> {
7739    pub fn offset(&self) -> MultiBufferOffset {
7740        self.range.start
7741    }
7742
7743    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7744        self.diff_transforms.seek(&range.end, Bias::Right);
7745        let mut excerpt_end = self.diff_transforms.start().1;
7746        if self
7747            .diff_transforms
7748            .item()
7749            .is_some_and(|t| t.is_buffer_content())
7750        {
7751            let overshoot = range.end - self.diff_transforms.start().0;
7752            excerpt_end += overshoot;
7753        }
7754
7755        self.diff_transforms.seek(&range.start, Bias::Right);
7756        let mut excerpt_start = self.diff_transforms.start().1;
7757        if self
7758            .diff_transforms
7759            .item()
7760            .is_some_and(|t| t.is_buffer_content())
7761        {
7762            let overshoot = range.start - self.diff_transforms.start().0;
7763            excerpt_start += overshoot;
7764        }
7765
7766        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7767        self.buffer_chunk.take();
7768        self.range = range;
7769    }
7770
7771    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7772        self.excerpt_offset_range = new_range.clone();
7773        self.excerpts.seek(&new_range.start, Bias::Right);
7774        if let Some(excerpt) = self.excerpts.item() {
7775            let excerpt_start = *self.excerpts.start();
7776            if let Some(excerpt_chunks) = self
7777                .excerpt_chunks
7778                .as_mut()
7779                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7780            {
7781                excerpt.seek_chunks(
7782                    excerpt_chunks,
7783                    (self.excerpt_offset_range.start - excerpt_start)
7784                        ..(self.excerpt_offset_range.end - excerpt_start),
7785                );
7786            } else {
7787                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7788                    (self.excerpt_offset_range.start - excerpt_start)
7789                        ..(self.excerpt_offset_range.end - excerpt_start),
7790                    self.language_aware,
7791                ));
7792            }
7793        } else {
7794            self.excerpt_chunks = None;
7795        }
7796    }
7797
7798    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7799        loop {
7800            if self.excerpt_offset_range.is_empty() {
7801                return None;
7802            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7803                self.excerpt_offset_range.start += chunk.text.len();
7804                return Some(chunk);
7805            } else {
7806                self.excerpts.next();
7807                let excerpt = self.excerpts.item()?;
7808                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7809                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7810                    self.language_aware,
7811                ));
7812            }
7813        }
7814    }
7815}
7816
7817impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7818    type Item = &'a str;
7819
7820    fn next(&mut self) -> Option<Self::Item> {
7821        let mut region = self.cursor.region()?;
7822        if self.offset == region.range.start {
7823            self.cursor.prev();
7824            while let Some(region) = self.cursor.region()
7825                && region.buffer_range.is_empty()
7826                && !region.has_trailing_newline
7827            {
7828                self.cursor.prev();
7829            }
7830            region = self.cursor.region()?;
7831            let start_overshoot = self.start.saturating_sub(region.range.start);
7832            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7833                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7834            ));
7835        }
7836
7837        if self.offset == region.range.end && region.has_trailing_newline {
7838            self.offset -= 1;
7839            Some("\n")
7840        } else {
7841            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7842            self.offset -= chunk.len();
7843            Some(chunk)
7844        }
7845    }
7846}
7847
7848impl<'a> Iterator for MultiBufferChunks<'a> {
7849    type Item = Chunk<'a>;
7850
7851    fn next(&mut self) -> Option<Chunk<'a>> {
7852        if self.range.start >= self.range.end {
7853            return None;
7854        }
7855        if self.range.start == self.diff_transforms.end().0 {
7856            self.diff_transforms.next();
7857        }
7858        while let Some(DiffTransform::FilteredInsertedHunk { .. }) = self.diff_transforms.item() {
7859            self.diff_transforms.next();
7860            let mut range = self.excerpt_offset_range.clone();
7861            range.start = self.diff_transforms.start().1;
7862            self.seek_to_excerpt_offset_range(range);
7863            self.buffer_chunk.take();
7864        }
7865
7866        let diff_transform_start = self.diff_transforms.start().0;
7867        let diff_transform_end = self.diff_transforms.end().0;
7868        debug_assert!(
7869            self.range.start < diff_transform_end,
7870            "{:?} < {:?} of ({1:?}..{2:?})",
7871            self.range.start,
7872            diff_transform_end,
7873            diff_transform_start
7874        );
7875
7876        let diff_transform = self.diff_transforms.item()?;
7877        match diff_transform {
7878            DiffTransform::Unmodified { .. }
7879            | DiffTransform::InsertedHunk { .. }
7880            | DiffTransform::FilteredInsertedHunk { .. } => {
7881                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7882                    chunk
7883                } else {
7884                    let chunk = self.next_excerpt_chunk().unwrap();
7885                    self.buffer_chunk.insert(chunk)
7886                };
7887
7888                let chunk_end = self.range.start + chunk.text.len();
7889                let diff_transform_end = diff_transform_end.min(self.range.end);
7890
7891                if diff_transform_end < chunk_end {
7892                    let split_idx = diff_transform_end - self.range.start;
7893                    let (before, after) = chunk.text.split_at(split_idx);
7894                    self.range.start = diff_transform_end;
7895                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7896                    let chars = chunk.chars & mask;
7897                    let tabs = chunk.tabs & mask;
7898
7899                    chunk.text = after;
7900                    chunk.chars = chunk.chars >> split_idx;
7901                    chunk.tabs = chunk.tabs >> split_idx;
7902
7903                    Some(Chunk {
7904                        text: before,
7905                        chars,
7906                        tabs,
7907                        ..chunk.clone()
7908                    })
7909                } else {
7910                    self.range.start = chunk_end;
7911                    self.buffer_chunk.take()
7912                }
7913            }
7914            DiffTransform::DeletedHunk {
7915                buffer_id,
7916                hunk_info,
7917                has_trailing_newline,
7918                ..
7919            } => {
7920                let base_text_start = hunk_info.base_text_byte_range.start
7921                    + (self.range.start - diff_transform_start);
7922                let base_text_end =
7923                    hunk_info.base_text_byte_range.start + (self.range.end - diff_transform_start);
7924                let base_text_end = base_text_end.min(hunk_info.base_text_byte_range.end);
7925
7926                let mut chunks = if let Some((_, mut chunks)) = self
7927                    .diff_base_chunks
7928                    .take()
7929                    .filter(|(id, _)| id == buffer_id)
7930                {
7931                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7932                    {
7933                        chunks.seek(base_text_start..base_text_end);
7934                    }
7935                    chunks
7936                } else {
7937                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7938                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7939                };
7940
7941                let chunk = if let Some(chunk) = chunks.next() {
7942                    self.range.start += chunk.text.len();
7943                    self.diff_base_chunks = Some((*buffer_id, chunks));
7944                    chunk
7945                } else {
7946                    debug_assert!(has_trailing_newline);
7947                    self.range.start += "\n".len();
7948                    Chunk {
7949                        text: "\n",
7950                        chars: 1u128,
7951                        ..Default::default()
7952                    }
7953                };
7954                Some(chunk)
7955            }
7956        }
7957    }
7958}
7959
7960impl MultiBufferBytes<'_> {
7961    fn consume(&mut self, len: usize) {
7962        self.range.start += len;
7963        self.chunk = &self.chunk[len..];
7964
7965        if !self.range.is_empty() && self.chunk.is_empty() {
7966            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7967                self.chunk = chunk;
7968            } else if self.has_trailing_newline {
7969                self.has_trailing_newline = false;
7970                self.chunk = b"\n";
7971            } else {
7972                self.cursor.next();
7973                while let Some(region) = self.cursor.region()
7974                    && region.buffer_range.is_empty()
7975                    && !region.has_trailing_newline
7976                {
7977                    self.cursor.next();
7978                }
7979                if let Some(region) = self.cursor.region() {
7980                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7981                        region.buffer_range.start
7982                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7983                                .min(region.buffer_range.end),
7984                    );
7985                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7986                    self.excerpt_bytes = Some(excerpt_bytes);
7987                    self.has_trailing_newline =
7988                        region.has_trailing_newline && self.range.end >= region.range.end;
7989                    if self.chunk.is_empty() && self.has_trailing_newline {
7990                        self.has_trailing_newline = false;
7991                        self.chunk = b"\n";
7992                    }
7993                }
7994            }
7995        }
7996    }
7997}
7998
7999impl<'a> Iterator for MultiBufferBytes<'a> {
8000    type Item = &'a [u8];
8001
8002    fn next(&mut self) -> Option<Self::Item> {
8003        let chunk = self.chunk;
8004        if chunk.is_empty() {
8005            None
8006        } else {
8007            self.consume(chunk.len());
8008            Some(chunk)
8009        }
8010    }
8011}
8012
8013impl io::Read for MultiBufferBytes<'_> {
8014    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8015        let len = cmp::min(buf.len(), self.chunk.len());
8016        buf[..len].copy_from_slice(&self.chunk[..len]);
8017        if len > 0 {
8018            self.consume(len);
8019        }
8020        Ok(len)
8021    }
8022}
8023
8024impl io::Read for ReversedMultiBufferBytes<'_> {
8025    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8026        let len = cmp::min(buf.len(), self.chunk.len());
8027        buf[..len].copy_from_slice(&self.chunk[..len]);
8028        buf[..len].reverse();
8029        if len > 0 {
8030            self.range.end -= len;
8031            self.chunk = &self.chunk[..self.chunk.len() - len];
8032            if !self.range.is_empty()
8033                && self.chunk.is_empty()
8034                && let Some(chunk) = self.chunks.next()
8035            {
8036                self.chunk = chunk.as_bytes();
8037            }
8038        }
8039        Ok(len)
8040    }
8041}
8042
8043impl<'a> Iterator for ExcerptChunks<'a> {
8044    type Item = Chunk<'a>;
8045
8046    fn next(&mut self) -> Option<Self::Item> {
8047        if let Some(chunk) = self.content_chunks.next() {
8048            return Some(chunk);
8049        }
8050
8051        if self.has_footer {
8052            let text = "\n";
8053            let chars = 0b1;
8054            self.has_footer = false;
8055            return Some(Chunk {
8056                text,
8057                chars,
8058                ..Default::default()
8059            });
8060        }
8061
8062        None
8063    }
8064}
8065
8066impl ToOffset for Point {
8067    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8068        snapshot.point_to_offset(*self)
8069    }
8070    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8071        snapshot.point_to_offset_utf16(*self)
8072    }
8073}
8074
8075impl ToOffset for MultiBufferOffset {
8076    #[track_caller]
8077    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8078        assert!(
8079            *self <= snapshot.len(),
8080            "offset {} is greater than the snapshot.len() {}",
8081            self.0,
8082            snapshot.len().0,
8083        );
8084        *self
8085    }
8086    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8087        snapshot.offset_to_offset_utf16(*self)
8088    }
8089}
8090
8091impl ToOffset for MultiBufferOffsetUtf16 {
8092    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8093        snapshot.offset_utf16_to_offset(*self)
8094    }
8095
8096    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8097        *self
8098    }
8099}
8100
8101impl ToOffset for PointUtf16 {
8102    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8103        snapshot.point_utf16_to_offset(*self)
8104    }
8105    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8106        snapshot.point_utf16_to_offset_utf16(*self)
8107    }
8108}
8109
8110impl ToPoint for MultiBufferOffset {
8111    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8112        snapshot.offset_to_point(*self)
8113    }
8114    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8115        snapshot.offset_to_point_utf16(*self)
8116    }
8117}
8118
8119impl ToPoint for Point {
8120    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8121        *self
8122    }
8123    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8124        snapshot.point_to_point_utf16(*self)
8125    }
8126}
8127
8128impl ToPoint for PointUtf16 {
8129    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8130        snapshot.point_utf16_to_point(*self)
8131    }
8132    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8133        *self
8134    }
8135}
8136
8137impl From<ExcerptId> for EntityId {
8138    fn from(id: ExcerptId) -> Self {
8139        EntityId::from(id.0 as u64)
8140    }
8141}
8142
8143#[cfg(debug_assertions)]
8144pub mod debug {
8145    use super::*;
8146
8147    pub trait ToMultiBufferDebugRanges {
8148        fn to_multi_buffer_debug_ranges(
8149            &self,
8150            snapshot: &MultiBufferSnapshot,
8151        ) -> Vec<Range<MultiBufferOffset>>;
8152    }
8153
8154    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8155        fn to_multi_buffer_debug_ranges(
8156            &self,
8157            snapshot: &MultiBufferSnapshot,
8158        ) -> Vec<Range<MultiBufferOffset>> {
8159            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8160        }
8161    }
8162
8163    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8164        fn to_multi_buffer_debug_ranges(
8165            &self,
8166            snapshot: &MultiBufferSnapshot,
8167        ) -> Vec<Range<MultiBufferOffset>> {
8168            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8169                .to_multi_buffer_debug_ranges(snapshot)
8170        }
8171    }
8172
8173    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8174        fn to_multi_buffer_debug_ranges(
8175            &self,
8176            snapshot: &MultiBufferSnapshot,
8177        ) -> Vec<Range<MultiBufferOffset>> {
8178            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8179        }
8180    }
8181
8182    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8183        fn to_multi_buffer_debug_ranges(
8184            &self,
8185            snapshot: &MultiBufferSnapshot,
8186        ) -> Vec<Range<MultiBufferOffset>> {
8187            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8188        }
8189    }
8190
8191    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8192        fn to_multi_buffer_debug_ranges(
8193            &self,
8194            snapshot: &MultiBufferSnapshot,
8195        ) -> Vec<Range<MultiBufferOffset>> {
8196            self.iter()
8197                .map(|item| {
8198                    let offset = item.to_offset(snapshot);
8199                    offset..offset
8200                })
8201                .collect()
8202        }
8203    }
8204
8205    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8206        fn to_multi_buffer_debug_ranges(
8207            &self,
8208            snapshot: &MultiBufferSnapshot,
8209        ) -> Vec<Range<MultiBufferOffset>> {
8210            self.iter()
8211                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8212                .collect()
8213        }
8214    }
8215}