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