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