multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunk,
  14    DiffHunkSecondaryStatus, DiffHunkStatus, 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, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  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;
  58use ztracing::instrument;
  59
  60pub use self::path_key::PathKey;
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    excerpts: Vec<Locator>,
 519    _subscriptions: [gpui::Subscription; 2],
 520}
 521
 522struct DiffState {
 523    diff: Entity<BufferDiff>,
 524    is_inverted: bool,
 525    _subscription: gpui::Subscription,
 526}
 527
 528impl DiffState {
 529    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 530        DiffStateSnapshot {
 531            diff: self.diff.read(cx).snapshot(cx),
 532            is_inverted: self.is_inverted,
 533        }
 534    }
 535}
 536
 537#[derive(Clone)]
 538struct DiffStateSnapshot {
 539    diff: BufferDiffSnapshot,
 540    is_inverted: bool,
 541}
 542
 543impl std::ops::Deref for DiffStateSnapshot {
 544    type Target = BufferDiffSnapshot;
 545
 546    fn deref(&self) -> &Self::Target {
 547        &self.diff
 548    }
 549}
 550
 551impl DiffState {
 552    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 553        DiffState {
 554            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 555                BufferDiffEvent::DiffChanged(DiffChanged {
 556                    changed_range,
 557                    base_text_changed_range: _,
 558                    extended_range,
 559                }) => {
 560                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 561                    let range = if use_extended {
 562                        extended_range.clone()
 563                    } else {
 564                        changed_range.clone()
 565                    };
 566                    if let Some(range) = range {
 567                        this.buffer_diff_changed(diff, range, cx)
 568                    }
 569                    cx.emit(Event::BufferDiffChanged);
 570                }
 571                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 572                _ => {}
 573            }),
 574            diff,
 575            is_inverted: false,
 576        }
 577    }
 578
 579    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 580        DiffState {
 581            _subscription: cx.subscribe(&diff, {
 582                move |this, diff, event, cx| match event {
 583                    BufferDiffEvent::DiffChanged(DiffChanged {
 584                        changed_range: _,
 585                        base_text_changed_range,
 586                        extended_range: _,
 587                    }) => {
 588                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 589                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 590                        }
 591                        cx.emit(Event::BufferDiffChanged);
 592                    }
 593                    BufferDiffEvent::LanguageChanged => {
 594                        this.inverted_buffer_diff_language_changed(diff, cx)
 595                    }
 596                    _ => {}
 597                }
 598            }),
 599            diff,
 600            is_inverted: true,
 601        }
 602    }
 603}
 604
 605/// The contents of a [`MultiBuffer`] at a single point in time.
 606#[derive(Clone, Default)]
 607pub struct MultiBufferSnapshot {
 608    excerpts: SumTree<Excerpt>,
 609    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 610    diff_transforms: SumTree<DiffTransform>,
 611    non_text_state_update_count: usize,
 612    edit_count: usize,
 613    is_dirty: bool,
 614    has_deleted_file: bool,
 615    has_conflict: bool,
 616    has_inverted_diff: bool,
 617    /// immutable fields
 618    singleton: bool,
 619    excerpt_ids: SumTree<ExcerptIdMapping>,
 620    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 621    trailing_excerpt_update_count: usize,
 622    all_diff_hunks_expanded: bool,
 623    show_deleted_hunks: bool,
 624    use_extended_diff_range: bool,
 625    show_headers: bool,
 626}
 627
 628// follower: None
 629// - BufferContent(Some)
 630// - BufferContent(None)
 631// - DeletedHunk
 632//
 633// follower: Some
 634// - BufferContent(Some)
 635// - BufferContent(None)
 636
 637#[derive(Debug, Clone)]
 638enum DiffTransform {
 639    // RealText
 640    BufferContent {
 641        summary: MBTextSummary,
 642        // modified_hunk_info
 643        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 644    },
 645    // ExpandedHunkText
 646    DeletedHunk {
 647        summary: TextSummary,
 648        buffer_id: BufferId,
 649        hunk_info: DiffTransformHunkInfo,
 650        base_text_byte_range: Range<usize>,
 651        has_trailing_newline: bool,
 652    },
 653}
 654
 655#[derive(Clone, Copy, Debug)]
 656struct DiffTransformHunkInfo {
 657    excerpt_id: ExcerptId,
 658    hunk_start_anchor: text::Anchor,
 659    hunk_secondary_status: DiffHunkSecondaryStatus,
 660    is_logically_deleted: bool,
 661}
 662
 663impl Eq for DiffTransformHunkInfo {}
 664
 665impl PartialEq for DiffTransformHunkInfo {
 666    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 667        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 668    }
 669}
 670
 671impl std::hash::Hash for DiffTransformHunkInfo {
 672    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 673        self.excerpt_id.hash(state);
 674        self.hunk_start_anchor.hash(state);
 675    }
 676}
 677
 678#[derive(Clone)]
 679pub struct ExcerptInfo {
 680    pub id: ExcerptId,
 681    pub buffer: Arc<BufferSnapshot>,
 682    pub buffer_id: BufferId,
 683    pub range: ExcerptRange<text::Anchor>,
 684    pub end_row: MultiBufferRow,
 685}
 686
 687impl std::fmt::Debug for ExcerptInfo {
 688    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 689        f.debug_struct(type_name::<Self>())
 690            .field("id", &self.id)
 691            .field("buffer_id", &self.buffer_id)
 692            .field("path", &self.buffer.file().map(|f| f.path()))
 693            .field("range", &self.range)
 694            .finish()
 695    }
 696}
 697
 698/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 699#[derive(Debug)]
 700pub struct ExcerptBoundary {
 701    pub prev: Option<ExcerptInfo>,
 702    pub next: ExcerptInfo,
 703    /// The row in the `MultiBuffer` where the boundary is located
 704    pub row: MultiBufferRow,
 705}
 706
 707impl ExcerptBoundary {
 708    pub fn starts_new_buffer(&self) -> bool {
 709        match (self.prev.as_ref(), &self.next) {
 710            (None, _) => true,
 711            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 712        }
 713    }
 714}
 715
 716#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 717pub struct ExpandInfo {
 718    pub direction: ExpandExcerptDirection,
 719    pub excerpt_id: ExcerptId,
 720}
 721
 722#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 723pub struct RowInfo {
 724    pub buffer_id: Option<BufferId>,
 725    pub buffer_row: Option<u32>,
 726    pub multibuffer_row: Option<MultiBufferRow>,
 727    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 728    pub expand_info: Option<ExpandInfo>,
 729    pub wrapped_buffer_row: Option<u32>,
 730}
 731
 732/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 733#[derive(Clone)]
 734struct Excerpt {
 735    /// The unique identifier for this excerpt
 736    id: ExcerptId,
 737    /// The location of the excerpt in the [`MultiBuffer`]
 738    locator: Locator,
 739    /// The buffer being excerpted
 740    buffer_id: BufferId,
 741    /// A snapshot of the buffer being excerpted
 742    buffer: Arc<BufferSnapshot>,
 743    /// The range of the buffer to be shown in the excerpt
 744    range: ExcerptRange<text::Anchor>,
 745    /// The last row in the excerpted slice of the buffer
 746    max_buffer_row: BufferRow,
 747    /// A summary of the text in the excerpt
 748    text_summary: TextSummary,
 749    has_trailing_newline: bool,
 750}
 751
 752/// A public view into an `Excerpt` in a [`MultiBuffer`].
 753///
 754/// Contains methods for getting the [`Buffer`] of the excerpt,
 755/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 756#[derive(Clone)]
 757pub struct MultiBufferExcerpt<'a> {
 758    excerpt: &'a Excerpt,
 759    diff_transforms:
 760        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 761    /// The offset in the multibuffer considering diff transforms.
 762    offset: MultiBufferOffset,
 763    /// The offset in the multibuffer without diff transforms.
 764    excerpt_offset: ExcerptOffset,
 765    buffer_offset: BufferOffset,
 766}
 767
 768#[derive(Clone, Debug)]
 769struct ExcerptIdMapping {
 770    id: ExcerptId,
 771    locator: Locator,
 772}
 773
 774/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 775/// These ranges are relative to the buffer itself
 776#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 777pub struct ExcerptRange<T> {
 778    /// The full range of text to be shown in the excerpt.
 779    pub context: Range<T>,
 780    /// The primary range of text to be highlighted in the excerpt.
 781    /// In a multi-buffer search, this would be the text that matched the search
 782    pub primary: Range<T>,
 783}
 784
 785impl<T: Clone> ExcerptRange<T> {
 786    pub fn new(context: Range<T>) -> Self {
 787        Self {
 788            context: context.clone(),
 789            primary: context,
 790        }
 791    }
 792}
 793
 794#[derive(Clone, Debug, Default)]
 795pub struct ExcerptSummary {
 796    excerpt_id: ExcerptId,
 797    /// The location of the last [`Excerpt`] being summarized
 798    excerpt_locator: Locator,
 799    widest_line_number: u32,
 800    text: MBTextSummary,
 801}
 802
 803#[derive(Debug, Clone)]
 804pub struct DiffTransformSummary {
 805    input: MBTextSummary,
 806    output: MBTextSummary,
 807}
 808
 809/// Summary of a string of text.
 810#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 811pub struct MBTextSummary {
 812    /// Length in bytes.
 813    pub len: MultiBufferOffset,
 814    /// Length in UTF-8.
 815    pub chars: usize,
 816    /// Length in UTF-16 code units
 817    pub len_utf16: OffsetUtf16,
 818    /// A point representing the number of lines and the length of the last line.
 819    ///
 820    /// In other words, it marks the point after the last byte in the text, (if
 821    /// EOF was a character, this would be its position).
 822    pub lines: Point,
 823    /// How many `char`s are in the first line
 824    pub first_line_chars: u32,
 825    /// How many `char`s are in the last line
 826    pub last_line_chars: u32,
 827    /// How many UTF-16 code units are in the last line
 828    pub last_line_len_utf16: u32,
 829    /// The row idx of the longest row
 830    pub longest_row: u32,
 831    /// How many `char`s are in the longest row
 832    pub longest_row_chars: u32,
 833}
 834
 835impl From<TextSummary> for MBTextSummary {
 836    fn from(summary: TextSummary) -> Self {
 837        MBTextSummary {
 838            len: MultiBufferOffset(summary.len),
 839            chars: summary.chars,
 840            len_utf16: summary.len_utf16,
 841            lines: summary.lines,
 842            first_line_chars: summary.first_line_chars,
 843            last_line_chars: summary.last_line_chars,
 844            last_line_len_utf16: summary.last_line_len_utf16,
 845            longest_row: summary.longest_row,
 846            longest_row_chars: summary.longest_row_chars,
 847        }
 848    }
 849}
 850
 851impl From<MBTextSummary> for TextSummary {
 852    fn from(summary: MBTextSummary) -> Self {
 853        TextSummary {
 854            len: summary.len.0,
 855            chars: summary.chars,
 856            len_utf16: summary.len_utf16,
 857            lines: summary.lines,
 858            first_line_chars: summary.first_line_chars,
 859            last_line_chars: summary.last_line_chars,
 860            last_line_len_utf16: summary.last_line_len_utf16,
 861            longest_row: summary.longest_row,
 862            longest_row_chars: summary.longest_row_chars,
 863        }
 864    }
 865}
 866
 867impl From<&str> for MBTextSummary {
 868    fn from(text: &str) -> Self {
 869        MBTextSummary::from(TextSummary::from(text))
 870    }
 871}
 872
 873impl MultiBufferDimension for MBTextSummary {
 874    type TextDimension = TextSummary;
 875
 876    fn from_summary(summary: &MBTextSummary) -> Self {
 877        *summary
 878    }
 879
 880    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 881        *self += *summary;
 882    }
 883
 884    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 885        *self += *summary;
 886    }
 887}
 888
 889impl AddAssign for MBTextSummary {
 890    fn add_assign(&mut self, other: MBTextSummary) {
 891        let joined_chars = self.last_line_chars + other.first_line_chars;
 892        if joined_chars > self.longest_row_chars {
 893            self.longest_row = self.lines.row;
 894            self.longest_row_chars = joined_chars;
 895        }
 896        if other.longest_row_chars > self.longest_row_chars {
 897            self.longest_row = self.lines.row + other.longest_row;
 898            self.longest_row_chars = other.longest_row_chars;
 899        }
 900
 901        if self.lines.row == 0 {
 902            self.first_line_chars += other.first_line_chars;
 903        }
 904
 905        if other.lines.row == 0 {
 906            self.last_line_chars += other.first_line_chars;
 907            self.last_line_len_utf16 += other.last_line_len_utf16;
 908        } else {
 909            self.last_line_chars = other.last_line_chars;
 910            self.last_line_len_utf16 = other.last_line_len_utf16;
 911        }
 912
 913        self.chars += other.chars;
 914        self.len += other.len;
 915        self.len_utf16 += other.len_utf16;
 916        self.lines += other.lines;
 917    }
 918}
 919
 920impl AddAssign<TextSummary> for MBTextSummary {
 921    fn add_assign(&mut self, other: TextSummary) {
 922        *self += MBTextSummary::from(other);
 923    }
 924}
 925
 926impl MBTextSummary {
 927    pub fn lines_utf16(&self) -> PointUtf16 {
 928        PointUtf16 {
 929            row: self.lines.row,
 930            column: self.last_line_len_utf16,
 931        }
 932    }
 933}
 934
 935impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 936where
 937    K: MultiBufferDimension,
 938    V: MultiBufferDimension,
 939{
 940    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 941
 942    fn from_summary(summary: &MBTextSummary) -> Self {
 943        Self {
 944            key: K::from_summary(summary),
 945            value: Some(V::from_summary(summary)),
 946        }
 947    }
 948
 949    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 950        self.key.add_text_dim(&summary.key);
 951        if let Some(value) = &mut self.value {
 952            if let Some(other_value) = summary.value.as_ref() {
 953                value.add_text_dim(other_value);
 954            }
 955        }
 956    }
 957
 958    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 959        self.key.add_mb_text_summary(summary);
 960        if let Some(value) = &mut self.value {
 961            value.add_mb_text_summary(summary);
 962        }
 963    }
 964}
 965
 966#[derive(Clone)]
 967pub struct MultiBufferRows<'a> {
 968    point: Point,
 969    is_empty: bool,
 970    is_singleton: bool,
 971    cursor: MultiBufferCursor<'a, Point, Point>,
 972}
 973
 974pub struct MultiBufferChunks<'a> {
 975    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 976    diff_transforms:
 977        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 978    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 979    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 980    buffer_chunk: Option<Chunk<'a>>,
 981    range: Range<MultiBufferOffset>,
 982    excerpt_offset_range: Range<ExcerptOffset>,
 983    excerpt_chunks: Option<ExcerptChunks<'a>>,
 984    language_aware: bool,
 985}
 986
 987pub struct ReversedMultiBufferChunks<'a> {
 988    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 989    current_chunks: Option<rope::Chunks<'a>>,
 990    start: MultiBufferOffset,
 991    offset: MultiBufferOffset,
 992}
 993
 994pub struct MultiBufferBytes<'a> {
 995    range: Range<MultiBufferOffset>,
 996    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 997    excerpt_bytes: Option<text::Bytes<'a>>,
 998    has_trailing_newline: bool,
 999    chunk: &'a [u8],
1000}
1001
1002pub struct ReversedMultiBufferBytes<'a> {
1003    range: Range<MultiBufferOffset>,
1004    chunks: ReversedMultiBufferChunks<'a>,
1005    chunk: &'a [u8],
1006}
1007
1008#[derive(Clone)]
1009struct DiffTransforms<MBD> {
1010    output_dimension: OutputDimension<MBD>,
1011    excerpt_dimension: ExcerptDimension<MBD>,
1012}
1013
1014impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1015    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1016        Self {
1017            output_dimension: OutputDimension::zero(cx),
1018            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1019                cx,
1020            ),
1021        }
1022    }
1023
1024    fn add_summary(
1025        &mut self,
1026        summary: &'a DiffTransformSummary,
1027        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1028    ) {
1029        self.output_dimension.add_summary(summary, cx);
1030        self.excerpt_dimension.add_summary(summary, cx);
1031    }
1032}
1033
1034#[derive(Clone)]
1035struct MultiBufferCursor<'a, MBD, BD> {
1036    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1037    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1038    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1039    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1040}
1041
1042#[derive(Clone)]
1043struct MultiBufferRegion<'a, MBD, BD> {
1044    buffer: &'a BufferSnapshot,
1045    is_main_buffer: bool,
1046    diff_hunk_status: Option<DiffHunkStatus>,
1047    excerpt: &'a Excerpt,
1048    buffer_range: Range<BD>,
1049    range: Range<MBD>,
1050    has_trailing_newline: bool,
1051}
1052
1053struct ExcerptChunks<'a> {
1054    excerpt_id: ExcerptId,
1055    content_chunks: BufferChunks<'a>,
1056    has_footer: bool,
1057}
1058
1059#[derive(Debug)]
1060struct BufferEdit {
1061    range: Range<BufferOffset>,
1062    new_text: Arc<str>,
1063    is_insertion: bool,
1064    original_indent_column: Option<u32>,
1065    excerpt_id: ExcerptId,
1066}
1067
1068#[derive(Clone, Copy, Debug, PartialEq)]
1069enum DiffChangeKind {
1070    BufferEdited,
1071    DiffUpdated { base_changed: bool },
1072    ExpandOrCollapseHunks { expand: bool },
1073}
1074
1075#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1076pub enum ExpandExcerptDirection {
1077    Up,
1078    Down,
1079    UpAndDown,
1080}
1081
1082impl ExpandExcerptDirection {
1083    pub fn should_expand_up(&self) -> bool {
1084        match self {
1085            ExpandExcerptDirection::Up => true,
1086            ExpandExcerptDirection::Down => false,
1087            ExpandExcerptDirection::UpAndDown => true,
1088        }
1089    }
1090
1091    pub fn should_expand_down(&self) -> bool {
1092        match self {
1093            ExpandExcerptDirection::Up => false,
1094            ExpandExcerptDirection::Down => true,
1095            ExpandExcerptDirection::UpAndDown => true,
1096        }
1097    }
1098}
1099
1100#[derive(Clone, Debug, PartialEq)]
1101pub struct IndentGuide {
1102    pub buffer_id: BufferId,
1103    pub start_row: MultiBufferRow,
1104    pub end_row: MultiBufferRow,
1105    pub depth: u32,
1106    pub tab_size: u32,
1107    pub settings: IndentGuideSettings,
1108}
1109
1110impl IndentGuide {
1111    pub fn indent_level(&self) -> u32 {
1112        self.depth * self.tab_size
1113    }
1114}
1115
1116impl MultiBuffer {
1117    pub fn new(capability: Capability) -> Self {
1118        Self::new_(
1119            capability,
1120            MultiBufferSnapshot {
1121                show_headers: true,
1122                show_deleted_hunks: true,
1123                ..MultiBufferSnapshot::default()
1124            },
1125        )
1126    }
1127
1128    pub fn without_headers(capability: Capability) -> Self {
1129        Self::new_(
1130            capability,
1131            MultiBufferSnapshot {
1132                show_deleted_hunks: true,
1133                ..MultiBufferSnapshot::default()
1134            },
1135        )
1136    }
1137
1138    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1139        let mut this = Self::new_(
1140            buffer.read(cx).capability(),
1141            MultiBufferSnapshot {
1142                singleton: true,
1143                show_deleted_hunks: true,
1144                ..MultiBufferSnapshot::default()
1145            },
1146        );
1147        this.singleton = true;
1148        let buffer_id = buffer.read(cx).remote_id();
1149        this.push_excerpts(
1150            buffer,
1151            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1152                buffer_id,
1153            ))],
1154            cx,
1155        );
1156        this
1157    }
1158
1159    #[inline]
1160    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1161        Self {
1162            snapshot: RefCell::new(snapshot),
1163            buffers: Default::default(),
1164            diffs: HashMap::default(),
1165            subscriptions: Topic::default(),
1166            singleton: false,
1167            capability,
1168            title: None,
1169            excerpts_by_path: Default::default(),
1170            paths_by_excerpt: Default::default(),
1171            buffer_changed_since_sync: Default::default(),
1172            history: History::default(),
1173        }
1174    }
1175
1176    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1177        let mut buffers = BTreeMap::default();
1178        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1179        for (buffer_id, buffer_state) in self.buffers.iter() {
1180            buffer_state.buffer.update(new_cx, |buffer, _| {
1181                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1182            });
1183            buffers.insert(
1184                *buffer_id,
1185                BufferState {
1186                    buffer: buffer_state.buffer.clone(),
1187                    last_version: buffer_state.last_version.clone(),
1188                    last_non_text_state_update_count: buffer_state
1189                        .last_non_text_state_update_count
1190                        .clone(),
1191                    excerpts: buffer_state.excerpts.clone(),
1192                    _subscriptions: [
1193                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1194                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1195                    ],
1196                },
1197            );
1198        }
1199        let mut diff_bases = HashMap::default();
1200        for (buffer_id, diff) in self.diffs.iter() {
1201            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1202        }
1203        Self {
1204            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1205            buffers: buffers,
1206            excerpts_by_path: Default::default(),
1207            paths_by_excerpt: Default::default(),
1208            diffs: diff_bases,
1209            subscriptions: Default::default(),
1210            singleton: self.singleton,
1211            capability: self.capability,
1212            history: self.history.clone(),
1213            title: self.title.clone(),
1214            buffer_changed_since_sync,
1215        }
1216    }
1217
1218    pub fn set_group_interval(&mut self, group_interval: Duration) {
1219        self.history.set_group_interval(group_interval);
1220    }
1221
1222    pub fn with_title(mut self, title: String) -> Self {
1223        self.title = Some(title);
1224        self
1225    }
1226
1227    pub fn read_only(&self) -> bool {
1228        !self.capability.editable()
1229    }
1230
1231    pub fn capability(&self) -> Capability {
1232        self.capability
1233    }
1234
1235    /// Returns an up-to-date snapshot of the MultiBuffer.
1236    #[ztracing::instrument(skip_all)]
1237    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1238        self.sync(cx);
1239        self.snapshot.borrow().clone()
1240    }
1241
1242    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1243        self.sync(cx);
1244        self.snapshot.borrow()
1245    }
1246
1247    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1248        if self.singleton {
1249            Some(self.buffers.values().next().unwrap().buffer.clone())
1250        } else {
1251            None
1252        }
1253    }
1254
1255    pub fn is_singleton(&self) -> bool {
1256        self.singleton
1257    }
1258
1259    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1260        self.subscriptions.subscribe()
1261    }
1262
1263    pub fn is_dirty(&self, cx: &App) -> bool {
1264        self.read(cx).is_dirty()
1265    }
1266
1267    pub fn has_deleted_file(&self, cx: &App) -> bool {
1268        self.read(cx).has_deleted_file()
1269    }
1270
1271    pub fn has_conflict(&self, cx: &App) -> bool {
1272        self.read(cx).has_conflict()
1273    }
1274
1275    // The `is_empty` signature doesn't match what clippy expects
1276    #[allow(clippy::len_without_is_empty)]
1277    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1278        self.read(cx).len()
1279    }
1280
1281    pub fn is_empty(&self) -> bool {
1282        self.buffers.is_empty()
1283    }
1284
1285    pub fn edit<I, S, T>(
1286        &mut self,
1287        edits: I,
1288        autoindent_mode: Option<AutoindentMode>,
1289        cx: &mut Context<Self>,
1290    ) where
1291        I: IntoIterator<Item = (Range<S>, T)>,
1292        S: ToOffset,
1293        T: Into<Arc<str>>,
1294    {
1295        self.edit_internal(edits, autoindent_mode, true, cx);
1296    }
1297
1298    pub fn edit_non_coalesce<I, S, T>(
1299        &mut self,
1300        edits: I,
1301        autoindent_mode: Option<AutoindentMode>,
1302        cx: &mut Context<Self>,
1303    ) where
1304        I: IntoIterator<Item = (Range<S>, T)>,
1305        S: ToOffset,
1306        T: Into<Arc<str>>,
1307    {
1308        self.edit_internal(edits, autoindent_mode, false, cx);
1309    }
1310
1311    fn edit_internal<I, S, T>(
1312        &mut self,
1313        edits: I,
1314        autoindent_mode: Option<AutoindentMode>,
1315        coalesce_adjacent: bool,
1316        cx: &mut Context<Self>,
1317    ) where
1318        I: IntoIterator<Item = (Range<S>, T)>,
1319        S: ToOffset,
1320        T: Into<Arc<str>>,
1321    {
1322        if self.read_only() || self.buffers.is_empty() {
1323            return;
1324        }
1325        self.sync_mut(cx);
1326        let edits = edits
1327            .into_iter()
1328            .map(|(range, new_text)| {
1329                let mut range = range.start.to_offset(self.snapshot.get_mut())
1330                    ..range.end.to_offset(self.snapshot.get_mut());
1331                if range.start > range.end {
1332                    mem::swap(&mut range.start, &mut range.end);
1333                }
1334                (range, new_text.into())
1335            })
1336            .collect::<Vec<_>>();
1337
1338        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1339
1340        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1341        fn edit_internal(
1342            this: &mut MultiBuffer,
1343            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1344            mut autoindent_mode: Option<AutoindentMode>,
1345            coalesce_adjacent: bool,
1346            cx: &mut Context<MultiBuffer>,
1347        ) {
1348            let original_indent_columns = match &mut autoindent_mode {
1349                Some(AutoindentMode::Block {
1350                    original_indent_columns,
1351                }) => mem::take(original_indent_columns),
1352                _ => Default::default(),
1353            };
1354
1355            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1356                edits,
1357                this.snapshot.get_mut(),
1358                &original_indent_columns,
1359            );
1360
1361            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1362            for (buffer_id, mut edits) in buffer_edits {
1363                buffer_ids.push(buffer_id);
1364                edits.sort_by_key(|edit| edit.range.start);
1365                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1366                    let mut edits = edits.into_iter().peekable();
1367                    let mut insertions = Vec::new();
1368                    let mut original_indent_columns = Vec::new();
1369                    let mut deletions = Vec::new();
1370                    let empty_str: Arc<str> = Arc::default();
1371                    while let Some(BufferEdit {
1372                        mut range,
1373                        mut new_text,
1374                        mut is_insertion,
1375                        original_indent_column,
1376                        excerpt_id,
1377                    }) = edits.next()
1378                    {
1379                        while let Some(BufferEdit {
1380                            range: next_range,
1381                            is_insertion: next_is_insertion,
1382                            new_text: next_new_text,
1383                            excerpt_id: next_excerpt_id,
1384                            ..
1385                        }) = edits.peek()
1386                        {
1387                            let should_coalesce = if coalesce_adjacent {
1388                                range.end >= next_range.start
1389                            } else {
1390                                range.end > next_range.start
1391                            };
1392
1393                            if should_coalesce {
1394                                range.end = cmp::max(next_range.end, range.end);
1395                                is_insertion |= *next_is_insertion;
1396                                if excerpt_id == *next_excerpt_id {
1397                                    new_text = format!("{new_text}{next_new_text}").into();
1398                                }
1399                                edits.next();
1400                            } else {
1401                                break;
1402                            }
1403                        }
1404
1405                        if is_insertion {
1406                            original_indent_columns.push(original_indent_column);
1407                            insertions.push((
1408                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1409                                new_text.clone(),
1410                            ));
1411                        } else if !range.is_empty() {
1412                            deletions.push((
1413                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1414                                empty_str.clone(),
1415                            ));
1416                        }
1417                    }
1418
1419                    let deletion_autoindent_mode =
1420                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1421                            Some(AutoindentMode::Block {
1422                                original_indent_columns: Default::default(),
1423                            })
1424                        } else {
1425                            autoindent_mode.clone()
1426                        };
1427                    let insertion_autoindent_mode =
1428                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1429                            Some(AutoindentMode::Block {
1430                                original_indent_columns,
1431                            })
1432                        } else {
1433                            autoindent_mode.clone()
1434                        };
1435
1436                    if coalesce_adjacent {
1437                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1438                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1439                    } else {
1440                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1441                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1442                    }
1443                })
1444            }
1445
1446            cx.emit(Event::ExcerptsEdited {
1447                excerpt_ids: edited_excerpt_ids,
1448                buffer_ids,
1449            });
1450        }
1451    }
1452
1453    fn convert_edits_to_buffer_edits(
1454        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1455        snapshot: &MultiBufferSnapshot,
1456        original_indent_columns: &[Option<u32>],
1457    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1458        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1459        let mut edited_excerpt_ids = Vec::new();
1460        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1461        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1462            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1463
1464            cursor.seek(&range.start);
1465            let mut start_region = cursor.region().expect("start offset out of bounds");
1466            if !start_region.is_main_buffer {
1467                cursor.next();
1468                if let Some(region) = cursor.region() {
1469                    start_region = region;
1470                } else {
1471                    continue;
1472                }
1473            }
1474
1475            if range.end < start_region.range.start {
1476                continue;
1477            }
1478
1479            let start_region = start_region.clone();
1480            if range.end > start_region.range.end {
1481                cursor.seek_forward(&range.end);
1482            }
1483            let mut end_region = cursor.region().expect("end offset out of bounds");
1484            if !end_region.is_main_buffer {
1485                cursor.prev();
1486                if let Some(region) = cursor.region() {
1487                    end_region = region;
1488                } else {
1489                    continue;
1490                }
1491            }
1492
1493            if range.start > end_region.range.end {
1494                continue;
1495            }
1496
1497            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1498            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1499            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1500                .min(start_region.buffer_range.end);
1501            let buffer_end =
1502                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1503
1504            if start_region.excerpt.id == end_region.excerpt.id {
1505                if start_region.buffer.capability == Capability::ReadWrite
1506                    && start_region.is_main_buffer
1507                {
1508                    edited_excerpt_ids.push(start_region.excerpt.id);
1509                    buffer_edits
1510                        .entry(start_region.buffer.remote_id())
1511                        .or_default()
1512                        .push(BufferEdit {
1513                            range: buffer_start..buffer_end,
1514                            new_text,
1515                            is_insertion: true,
1516                            original_indent_column,
1517                            excerpt_id: start_region.excerpt.id,
1518                        });
1519                }
1520            } else {
1521                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1522                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1523                if start_region.buffer.capability == Capability::ReadWrite
1524                    && start_region.is_main_buffer
1525                {
1526                    edited_excerpt_ids.push(start_region.excerpt.id);
1527                    buffer_edits
1528                        .entry(start_region.buffer.remote_id())
1529                        .or_default()
1530                        .push(BufferEdit {
1531                            range: start_excerpt_range,
1532                            new_text: new_text.clone(),
1533                            is_insertion: true,
1534                            original_indent_column,
1535                            excerpt_id: start_region.excerpt.id,
1536                        });
1537                }
1538                let excerpt_id = end_region.excerpt.id;
1539                if end_region.buffer.capability == Capability::ReadWrite
1540                    && end_region.is_main_buffer
1541                {
1542                    edited_excerpt_ids.push(excerpt_id);
1543                    buffer_edits
1544                        .entry(end_region.buffer.remote_id())
1545                        .or_default()
1546                        .push(BufferEdit {
1547                            range: end_excerpt_range,
1548                            new_text: new_text.clone(),
1549                            is_insertion: false,
1550                            original_indent_column,
1551                            excerpt_id,
1552                        });
1553                }
1554
1555                cursor.seek(&range.start);
1556                cursor.next_excerpt();
1557                while let Some(region) = cursor.region() {
1558                    if region.excerpt.id == excerpt_id {
1559                        break;
1560                    }
1561                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1562                        edited_excerpt_ids.push(region.excerpt.id);
1563                        buffer_edits
1564                            .entry(region.buffer.remote_id())
1565                            .or_default()
1566                            .push(BufferEdit {
1567                                range: region.buffer_range.clone(),
1568                                new_text: new_text.clone(),
1569                                is_insertion: false,
1570                                original_indent_column,
1571                                excerpt_id: region.excerpt.id,
1572                            });
1573                    }
1574                    cursor.next_excerpt();
1575                }
1576            }
1577        }
1578        (buffer_edits, edited_excerpt_ids)
1579    }
1580
1581    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1582    where
1583        I: IntoIterator<Item = Range<S>>,
1584        S: ToOffset,
1585    {
1586        if self.read_only() || self.buffers.is_empty() {
1587            return;
1588        }
1589        self.sync_mut(cx);
1590        let empty = Arc::<str>::from("");
1591        let edits = ranges
1592            .into_iter()
1593            .map(|range| {
1594                let mut range = range.start.to_offset(self.snapshot.get_mut())
1595                    ..range.end.to_offset(&self.snapshot.get_mut());
1596                if range.start > range.end {
1597                    mem::swap(&mut range.start, &mut range.end);
1598                }
1599                (range, empty.clone())
1600            })
1601            .collect::<Vec<_>>();
1602
1603        return autoindent_ranges_internal(self, edits, cx);
1604
1605        fn autoindent_ranges_internal(
1606            this: &mut MultiBuffer,
1607            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1608            cx: &mut Context<MultiBuffer>,
1609        ) {
1610            let (buffer_edits, edited_excerpt_ids) =
1611                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1612
1613            let mut buffer_ids = Vec::new();
1614            for (buffer_id, mut edits) in buffer_edits {
1615                buffer_ids.push(buffer_id);
1616                edits.sort_unstable_by_key(|edit| edit.range.start);
1617
1618                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1619                for edit in edits {
1620                    if let Some(last_range) = ranges.last_mut()
1621                        && edit.range.start <= last_range.end
1622                    {
1623                        last_range.end = last_range.end.max(edit.range.end);
1624                        continue;
1625                    }
1626                    ranges.push(edit.range);
1627                }
1628
1629                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1630                    buffer.autoindent_ranges(ranges, cx);
1631                })
1632            }
1633
1634            cx.emit(Event::ExcerptsEdited {
1635                excerpt_ids: edited_excerpt_ids,
1636                buffer_ids,
1637            });
1638        }
1639    }
1640
1641    pub fn set_active_selections(
1642        &self,
1643        selections: &[Selection<Anchor>],
1644        line_mode: bool,
1645        cursor_shape: CursorShape,
1646        cx: &mut Context<Self>,
1647    ) {
1648        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1649            Default::default();
1650        let snapshot = self.read(cx);
1651        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1652        for selection in selections {
1653            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1654            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1655
1656            cursor.seek(&Some(start_locator), Bias::Left);
1657            while let Some(excerpt) = cursor.item()
1658                && excerpt.locator <= *end_locator
1659            {
1660                let mut start = excerpt.range.context.start;
1661                let mut end = excerpt.range.context.end;
1662                if excerpt.id == selection.start.excerpt_id {
1663                    start = selection.start.text_anchor;
1664                }
1665                if excerpt.id == selection.end.excerpt_id {
1666                    end = selection.end.text_anchor;
1667                }
1668                selections_by_buffer
1669                    .entry(excerpt.buffer_id)
1670                    .or_default()
1671                    .push(Selection {
1672                        id: selection.id,
1673                        start,
1674                        end,
1675                        reversed: selection.reversed,
1676                        goal: selection.goal,
1677                    });
1678
1679                cursor.next();
1680            }
1681        }
1682
1683        for (buffer_id, buffer_state) in self.buffers.iter() {
1684            if !selections_by_buffer.contains_key(buffer_id) {
1685                buffer_state
1686                    .buffer
1687                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1688            }
1689        }
1690
1691        for (buffer_id, mut selections) in selections_by_buffer {
1692            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1693                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1694                let mut selections = selections.into_iter().peekable();
1695                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1696                    let mut selection = selections.next()?;
1697                    while let Some(next_selection) = selections.peek() {
1698                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1699                            let next_selection = selections.next().unwrap();
1700                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1701                                selection.end = next_selection.end;
1702                            }
1703                        } else {
1704                            break;
1705                        }
1706                    }
1707                    Some(selection)
1708                }));
1709                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1710            });
1711        }
1712    }
1713
1714    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1715        for buffer in self.buffers.values() {
1716            buffer
1717                .buffer
1718                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1719        }
1720    }
1721
1722    pub fn push_excerpts<O>(
1723        &mut self,
1724        buffer: Entity<Buffer>,
1725        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1726        cx: &mut Context<Self>,
1727    ) -> Vec<ExcerptId>
1728    where
1729        O: text::ToOffset,
1730    {
1731        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1732    }
1733
1734    #[instrument(skip_all)]
1735    fn merge_excerpt_ranges<'a>(
1736        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1737    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1738        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1739        let mut counts: Vec<usize> = Vec::new();
1740        for range in expanded_ranges {
1741            if let Some(last_range) = merged_ranges.last_mut() {
1742                assert!(
1743                    last_range.context.start <= range.context.start,
1744                    "ranges must be sorted: {last_range:?} <= {range:?}"
1745                );
1746                if last_range.context.end >= range.context.start
1747                    || last_range.context.end.row + 1 == range.context.start.row
1748                {
1749                    last_range.context.end = range.context.end.max(last_range.context.end);
1750                    *counts.last_mut().unwrap() += 1;
1751                    continue;
1752                }
1753            }
1754            merged_ranges.push(range.clone());
1755            counts.push(1);
1756        }
1757        (merged_ranges, counts)
1758    }
1759
1760    pub fn insert_excerpts_after<O>(
1761        &mut self,
1762        prev_excerpt_id: ExcerptId,
1763        buffer: Entity<Buffer>,
1764        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1765        cx: &mut Context<Self>,
1766    ) -> Vec<ExcerptId>
1767    where
1768        O: text::ToOffset,
1769    {
1770        let mut ids = Vec::new();
1771        let mut next_excerpt_id =
1772            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1773                last_entry.id.0 + 1
1774            } else {
1775                1
1776            };
1777        self.insert_excerpts_with_ids_after(
1778            prev_excerpt_id,
1779            buffer,
1780            ranges.into_iter().map(|range| {
1781                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1782                ids.push(id);
1783                (id, range)
1784            }),
1785            cx,
1786        );
1787        ids
1788    }
1789
1790    pub fn insert_excerpts_with_ids_after<O>(
1791        &mut self,
1792        prev_excerpt_id: ExcerptId,
1793        buffer: Entity<Buffer>,
1794        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1795        cx: &mut Context<Self>,
1796    ) where
1797        O: text::ToOffset,
1798    {
1799        assert_eq!(self.history.transaction_depth(), 0);
1800        let mut ranges = ranges.into_iter().peekable();
1801        if ranges.peek().is_none() {
1802            return Default::default();
1803        }
1804
1805        self.sync_mut(cx);
1806
1807        let buffer_snapshot = buffer.read(cx).snapshot();
1808        let buffer_id = buffer_snapshot.remote_id();
1809
1810        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1811            self.buffer_changed_since_sync.replace(true);
1812            buffer.update(cx, |buffer, _| {
1813                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1814            });
1815            BufferState {
1816                last_version: RefCell::new(buffer_snapshot.version().clone()),
1817                last_non_text_state_update_count: Cell::new(
1818                    buffer_snapshot.non_text_state_update_count(),
1819                ),
1820                excerpts: Default::default(),
1821                _subscriptions: [
1822                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1823                    cx.subscribe(&buffer, Self::on_buffer_event),
1824                ],
1825                buffer: buffer.clone(),
1826            }
1827        });
1828
1829        let mut snapshot = self.snapshot.get_mut();
1830
1831        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1832        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1833        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1834        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1835        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1836
1837        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1838        new_excerpts.update_last(
1839            |excerpt| {
1840                excerpt.has_trailing_newline = true;
1841            },
1842            (),
1843        );
1844
1845        let next_locator = if let Some(excerpt) = cursor.item() {
1846            excerpt.locator.clone()
1847        } else {
1848            Locator::max()
1849        };
1850
1851        let mut excerpts = Vec::new();
1852        let buffer_snapshot = Arc::new(buffer_snapshot);
1853        while let Some((id, range)) = ranges.next() {
1854            let locator = Locator::between(&prev_locator, &next_locator);
1855            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1856                buffer_state.excerpts.insert(ix, locator.clone());
1857            }
1858            let range = ExcerptRange {
1859                context: buffer_snapshot.anchor_before(&range.context.start)
1860                    ..buffer_snapshot.anchor_after(&range.context.end),
1861                primary: buffer_snapshot.anchor_before(&range.primary.start)
1862                    ..buffer_snapshot.anchor_after(&range.primary.end),
1863            };
1864            excerpts.push((id, range.clone()));
1865            let excerpt = Excerpt::new(
1866                id,
1867                locator.clone(),
1868                buffer_id,
1869                buffer_snapshot.clone(),
1870                range,
1871                ranges.peek().is_some() || cursor.item().is_some(),
1872            );
1873            new_excerpts.push(excerpt, ());
1874            prev_locator = locator.clone();
1875
1876            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1877                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1878            }
1879            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1880        }
1881
1882        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1883
1884        let suffix = cursor.suffix();
1885        let changed_trailing_excerpt = suffix.is_empty();
1886        new_excerpts.append(suffix, ());
1887        drop(cursor);
1888        snapshot.excerpts = new_excerpts;
1889        snapshot.excerpt_ids = new_excerpt_ids;
1890        if changed_trailing_excerpt {
1891            snapshot.trailing_excerpt_update_count += 1;
1892        }
1893
1894        let edits = Self::sync_diff_transforms(
1895            &mut snapshot,
1896            vec![Edit {
1897                old: edit_start..edit_start,
1898                new: edit_start..edit_end,
1899            }],
1900            DiffChangeKind::BufferEdited,
1901        );
1902        if !edits.is_empty() {
1903            self.subscriptions.publish(edits);
1904        }
1905
1906        cx.emit(Event::Edited {
1907            edited_buffer: None,
1908        });
1909        cx.emit(Event::ExcerptsAdded {
1910            buffer,
1911            predecessor: prev_excerpt_id,
1912            excerpts,
1913        });
1914        cx.notify();
1915    }
1916
1917    pub fn clear(&mut self, cx: &mut Context<Self>) {
1918        self.sync_mut(cx);
1919        let ids = self.excerpt_ids();
1920        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1921        self.excerpts_by_path.clear();
1922        self.paths_by_excerpt.clear();
1923        let MultiBufferSnapshot {
1924            excerpts,
1925            diffs: _,
1926            diff_transforms: _,
1927            non_text_state_update_count: _,
1928            edit_count: _,
1929            is_dirty,
1930            has_deleted_file,
1931            has_conflict,
1932            has_inverted_diff,
1933            singleton: _,
1934            excerpt_ids: _,
1935            replaced_excerpts,
1936            trailing_excerpt_update_count,
1937            all_diff_hunks_expanded: _,
1938            show_deleted_hunks: _,
1939            use_extended_diff_range: _,
1940            show_headers: _,
1941        } = self.snapshot.get_mut();
1942        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1943        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1944        *excerpts = Default::default();
1945        *trailing_excerpt_update_count += 1;
1946        *is_dirty = false;
1947        *has_deleted_file = false;
1948        *has_conflict = false;
1949        *has_inverted_diff = false;
1950        replaced_excerpts.clear();
1951
1952        let edits = Self::sync_diff_transforms(
1953            self.snapshot.get_mut(),
1954            vec![Edit {
1955                old: start..prev_len,
1956                new: start..start,
1957            }],
1958            DiffChangeKind::BufferEdited,
1959        );
1960        if !edits.is_empty() {
1961            self.subscriptions.publish(edits);
1962        }
1963        cx.emit(Event::Edited {
1964            edited_buffer: None,
1965        });
1966        cx.emit(Event::ExcerptsRemoved {
1967            ids,
1968            removed_buffer_ids,
1969        });
1970        cx.notify();
1971    }
1972
1973    #[ztracing::instrument(skip_all)]
1974    pub fn excerpts_for_buffer(
1975        &self,
1976        buffer_id: BufferId,
1977        cx: &App,
1978    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1979        let mut excerpts = Vec::new();
1980        let snapshot = self.read(cx);
1981        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1982        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1983            for locator in locators {
1984                cursor.seek_forward(&Some(locator), Bias::Left);
1985                if let Some(excerpt) = cursor.item()
1986                    && excerpt.locator == *locator
1987                {
1988                    excerpts.push((excerpt.id, excerpt.range.clone()));
1989                }
1990            }
1991        }
1992
1993        excerpts
1994    }
1995
1996    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1997        let snapshot = self.read(cx);
1998        let mut excerpts = snapshot
1999            .excerpts
2000            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2001        let mut diff_transforms = snapshot
2002            .diff_transforms
2003            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2004        diff_transforms.next();
2005        let locators = self
2006            .buffers
2007            .get(&buffer_id)
2008            .into_iter()
2009            .flat_map(|state| &state.excerpts);
2010        let mut result = Vec::new();
2011        for locator in locators {
2012            excerpts.seek_forward(&Some(locator), Bias::Left);
2013            if let Some(excerpt) = excerpts.item()
2014                && excerpt.locator == *locator
2015            {
2016                let excerpt_start = excerpts.start().1;
2017                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2018
2019                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2020                let overshoot = excerpt_start - diff_transforms.start().0;
2021                let start = diff_transforms.start().1 + overshoot;
2022
2023                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2024                let overshoot = excerpt_end - diff_transforms.start().0;
2025                let end = diff_transforms.start().1 + overshoot;
2026
2027                result.push(start.0..end.0)
2028            }
2029        }
2030        result
2031    }
2032
2033    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2034        self.snapshot
2035            .borrow()
2036            .excerpts
2037            .iter()
2038            .map(|entry| entry.buffer_id)
2039            .collect()
2040    }
2041
2042    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2043        self.snapshot
2044            .borrow()
2045            .excerpts
2046            .iter()
2047            .map(|entry| entry.id)
2048            .collect()
2049    }
2050
2051    pub fn excerpt_containing(
2052        &self,
2053        position: impl ToOffset,
2054        cx: &App,
2055    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2056        let snapshot = self.read(cx);
2057        let offset = position.to_offset(&snapshot);
2058
2059        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2060        cursor.seek(&offset);
2061        cursor
2062            .excerpt()
2063            .or_else(|| snapshot.excerpts.last())
2064            .map(|excerpt| {
2065                (
2066                    excerpt.id,
2067                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2068                    excerpt.range.context.clone(),
2069                )
2070            })
2071    }
2072
2073    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2074        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2075            self.buffer(buffer_id)
2076        } else {
2077            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2078            Some(buffer)
2079        }
2080    }
2081
2082    // If point is at the end of the buffer, the last excerpt is returned
2083    pub fn point_to_buffer_offset<T: ToOffset>(
2084        &self,
2085        point: T,
2086        cx: &App,
2087    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2088        let snapshot = self.read(cx);
2089        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2090        Some((
2091            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2092            offset,
2093        ))
2094    }
2095
2096    // If point is at the end of the buffer, the last excerpt is returned
2097    pub fn point_to_buffer_point<T: ToPoint>(
2098        &self,
2099        point: T,
2100        cx: &App,
2101    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2102        let snapshot = self.read(cx);
2103        let (buffer, point, is_main_buffer) =
2104            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2105        Some((
2106            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2107            point,
2108            is_main_buffer,
2109        ))
2110    }
2111
2112    pub fn buffer_point_to_anchor(
2113        &self,
2114        buffer: &Entity<Buffer>,
2115        point: Point,
2116        cx: &App,
2117    ) -> Option<Anchor> {
2118        let mut found = None;
2119        let snapshot = buffer.read(cx).snapshot();
2120        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2121            let start = range.context.start.to_point(&snapshot);
2122            let end = range.context.end.to_point(&snapshot);
2123            if start <= point && point < end {
2124                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2125                break;
2126            }
2127            if point < start {
2128                found = Some((start, excerpt_id));
2129            }
2130            if point > end {
2131                found = Some((end, excerpt_id));
2132            }
2133        }
2134
2135        found.map(|(point, excerpt_id)| {
2136            let text_anchor = snapshot.anchor_after(point);
2137            Anchor::in_buffer(excerpt_id, text_anchor)
2138        })
2139    }
2140
2141    pub fn buffer_anchor_to_anchor(
2142        &self,
2143        buffer: &Entity<Buffer>,
2144        anchor: text::Anchor,
2145        cx: &App,
2146    ) -> Option<Anchor> {
2147        let snapshot = buffer.read(cx).snapshot();
2148        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2149            if range.context.start.cmp(&anchor, &snapshot).is_le()
2150                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2151            {
2152                return Some(Anchor::in_buffer(excerpt_id, anchor));
2153            }
2154        }
2155
2156        None
2157    }
2158
2159    pub fn remove_excerpts(
2160        &mut self,
2161        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2162        cx: &mut Context<Self>,
2163    ) {
2164        self.sync_mut(cx);
2165        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2166        if ids.is_empty() {
2167            return;
2168        }
2169        self.buffer_changed_since_sync.replace(true);
2170
2171        let mut snapshot = self.snapshot.get_mut();
2172        let mut new_excerpts = SumTree::default();
2173        let mut cursor = snapshot
2174            .excerpts
2175            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2176        let mut edits = Vec::new();
2177        let mut excerpt_ids = ids.iter().copied().peekable();
2178        let mut removed_buffer_ids = Vec::new();
2179
2180        while let Some(excerpt_id) = excerpt_ids.next() {
2181            self.paths_by_excerpt.remove(&excerpt_id);
2182            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2183            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2184            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2185
2186            if let Some(mut excerpt) = cursor.item() {
2187                if excerpt.id != excerpt_id {
2188                    continue;
2189                }
2190                let mut old_start = cursor.start().1;
2191
2192                // Skip over the removed excerpt.
2193                'remove_excerpts: loop {
2194                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2195                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2196                        if buffer_state.excerpts.is_empty() {
2197                            log::debug!(
2198                                "removing buffer and diff for buffer {}",
2199                                excerpt.buffer_id
2200                            );
2201                            self.buffers.remove(&excerpt.buffer_id);
2202                            removed_buffer_ids.push(excerpt.buffer_id);
2203                        }
2204                    }
2205                    cursor.next();
2206
2207                    // Skip over any subsequent excerpts that are also removed.
2208                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2209                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2210                        if let Some(next_excerpt) = cursor.item()
2211                            && next_excerpt.locator == *next_locator
2212                        {
2213                            excerpt_ids.next();
2214                            excerpt = next_excerpt;
2215                            continue 'remove_excerpts;
2216                        }
2217                    }
2218
2219                    break;
2220                }
2221
2222                // When removing the last excerpt, remove the trailing newline from
2223                // the previous excerpt.
2224                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2225                    old_start -= 1;
2226                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2227                }
2228
2229                // Push an edit for the removal of this run of excerpts.
2230                let old_end = cursor.start().1;
2231                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2232                edits.push(Edit {
2233                    old: old_start..old_end,
2234                    new: new_start..new_start,
2235                });
2236            }
2237        }
2238        let suffix = cursor.suffix();
2239        let changed_trailing_excerpt = suffix.is_empty();
2240        new_excerpts.append(suffix, ());
2241        drop(cursor);
2242        snapshot.excerpts = new_excerpts;
2243        for buffer_id in &removed_buffer_ids {
2244            self.diffs.remove(buffer_id);
2245            snapshot.diffs.remove(buffer_id);
2246        }
2247
2248        // Recalculate has_inverted_diff after removing diffs
2249        if !removed_buffer_ids.is_empty() {
2250            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2251        }
2252
2253        if changed_trailing_excerpt {
2254            snapshot.trailing_excerpt_update_count += 1;
2255        }
2256
2257        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2258        if !edits.is_empty() {
2259            self.subscriptions.publish(edits);
2260        }
2261        cx.emit(Event::Edited {
2262            edited_buffer: None,
2263        });
2264        cx.emit(Event::ExcerptsRemoved {
2265            ids,
2266            removed_buffer_ids,
2267        });
2268        cx.notify();
2269    }
2270
2271    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2272        &self,
2273        anchors: Anchors,
2274        cx: &mut Context<Self>,
2275    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2276        let mut error = None;
2277        let mut futures = Vec::new();
2278        for anchor in anchors {
2279            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2280                if let Some(buffer) = self.buffers.get(&buffer_id) {
2281                    buffer.buffer.update(cx, |buffer, _| {
2282                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2283                    });
2284                } else {
2285                    error = Some(anyhow!(
2286                        "buffer {buffer_id} is not part of this multi-buffer"
2287                    ));
2288                    break;
2289                }
2290            }
2291        }
2292        async move {
2293            if let Some(error) = error {
2294                Err(error)?;
2295            }
2296            for future in futures {
2297                future.await?;
2298            }
2299            Ok(())
2300        }
2301    }
2302
2303    pub fn text_anchor_for_position<T: ToOffset>(
2304        &self,
2305        position: T,
2306        cx: &App,
2307    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2308        let snapshot = self.read(cx);
2309        let anchor = snapshot.anchor_before(position);
2310        let buffer = self
2311            .buffers
2312            .get(&anchor.text_anchor.buffer_id?)?
2313            .buffer
2314            .clone();
2315        Some((buffer, anchor.text_anchor))
2316    }
2317
2318    fn on_buffer_event(
2319        &mut self,
2320        buffer: Entity<Buffer>,
2321        event: &language::BufferEvent,
2322        cx: &mut Context<Self>,
2323    ) {
2324        use language::BufferEvent;
2325        let buffer_id = buffer.read(cx).remote_id();
2326        cx.emit(match event {
2327            BufferEvent::Edited => Event::Edited {
2328                edited_buffer: Some(buffer),
2329            },
2330            BufferEvent::DirtyChanged => Event::DirtyChanged,
2331            BufferEvent::Saved => Event::Saved,
2332            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2333            BufferEvent::Reloaded => Event::Reloaded,
2334            BufferEvent::LanguageChanged(has_language) => {
2335                Event::LanguageChanged(buffer_id, *has_language)
2336            }
2337            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2338            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2339            BufferEvent::CapabilityChanged => {
2340                self.capability = buffer.read(cx).capability();
2341                return;
2342            }
2343            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2344        });
2345    }
2346
2347    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2348        let diff = diff.read(cx);
2349        let buffer_id = diff.buffer_id;
2350        let diff = DiffStateSnapshot {
2351            diff: diff.snapshot(cx),
2352            is_inverted: false,
2353        };
2354        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2355    }
2356
2357    fn inverted_buffer_diff_language_changed(
2358        &mut self,
2359        diff: Entity<BufferDiff>,
2360        cx: &mut Context<Self>,
2361    ) {
2362        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2363        let diff = diff.read(cx);
2364        let diff = DiffStateSnapshot {
2365            diff: diff.snapshot(cx),
2366            is_inverted: true,
2367        };
2368        self.snapshot
2369            .get_mut()
2370            .diffs
2371            .insert(base_text_buffer_id, diff);
2372    }
2373
2374    fn buffer_diff_changed(
2375        &mut self,
2376        diff: Entity<BufferDiff>,
2377        range: Range<text::Anchor>,
2378        cx: &mut Context<Self>,
2379    ) {
2380        self.sync_mut(cx);
2381
2382        let diff = diff.read(cx);
2383        let buffer_id = diff.buffer_id;
2384
2385        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2386            return;
2387        };
2388        let new_diff = DiffStateSnapshot {
2389            diff: diff.snapshot(cx),
2390            is_inverted: false,
2391        };
2392        let mut snapshot = self.snapshot.get_mut();
2393        let base_text_changed = snapshot
2394            .diffs
2395            .get(&buffer_id)
2396            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2397        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2398
2399        let buffer = buffer_state.buffer.read(cx);
2400        let diff_change_range = range.to_offset(buffer);
2401
2402        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2403        let edits = Self::sync_diff_transforms(
2404            &mut snapshot,
2405            excerpt_edits,
2406            DiffChangeKind::DiffUpdated {
2407                base_changed: base_text_changed,
2408            },
2409        );
2410        if !edits.is_empty() {
2411            self.subscriptions.publish(edits);
2412        }
2413        cx.emit(Event::Edited {
2414            edited_buffer: None,
2415        });
2416    }
2417
2418    fn inverted_buffer_diff_changed(
2419        &mut self,
2420        diff: Entity<BufferDiff>,
2421        diff_change_range: Range<usize>,
2422        cx: &mut Context<Self>,
2423    ) {
2424        self.sync_mut(cx);
2425
2426        let diff = diff.read(cx);
2427        let base_text_buffer_id = diff.base_text(cx).remote_id();
2428        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2429            return;
2430        };
2431
2432        let new_diff = DiffStateSnapshot {
2433            diff: diff.snapshot(cx),
2434            is_inverted: true,
2435        };
2436        let mut snapshot = self.snapshot.get_mut();
2437        snapshot
2438            .diffs
2439            .insert_or_replace(base_text_buffer_id, new_diff);
2440
2441        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2442        let edits = Self::sync_diff_transforms(
2443            &mut snapshot,
2444            excerpt_edits,
2445            DiffChangeKind::DiffUpdated {
2446                // We don't read this field for inverted diffs.
2447                base_changed: false,
2448            },
2449        );
2450        if !edits.is_empty() {
2451            self.subscriptions.publish(edits);
2452        }
2453        cx.emit(Event::Edited {
2454            edited_buffer: None,
2455        });
2456    }
2457
2458    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2459        self.buffers.values().map(|state| state.buffer.clone())
2460    }
2461
2462    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2463        self.all_buffers_iter().collect()
2464    }
2465
2466    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2467        self.buffers.keys().copied()
2468    }
2469
2470    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2471        self.all_buffer_ids_iter().collect()
2472    }
2473
2474    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2475        self.buffers
2476            .get(&buffer_id)
2477            .map(|state| state.buffer.clone())
2478    }
2479
2480    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2481        self.point_to_buffer_offset(point, cx)
2482            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2483    }
2484
2485    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2486        let buffer_id = self
2487            .snapshot
2488            .borrow()
2489            .excerpts
2490            .first()
2491            .map(|excerpt| excerpt.buffer.remote_id());
2492        buffer_id
2493            .and_then(|buffer_id| self.buffer(buffer_id))
2494            .map(|buffer| {
2495                let buffer = buffer.read(cx);
2496                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2497            })
2498            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2499    }
2500
2501    pub fn language_settings_at<'a, T: ToOffset>(
2502        &'a self,
2503        point: T,
2504        cx: &'a App,
2505    ) -> Cow<'a, LanguageSettings> {
2506        let mut language = None;
2507        let mut file = None;
2508        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2509            let buffer = buffer.read(cx);
2510            language = buffer.language_at(offset);
2511            file = buffer.file();
2512        }
2513        language_settings(language.map(|l| l.name()), file, cx)
2514    }
2515
2516    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2517        self.buffers.values().for_each(|state| f(&state.buffer))
2518    }
2519
2520    pub fn explicit_title(&self) -> Option<&str> {
2521        self.title.as_deref()
2522    }
2523
2524    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2525        if let Some(title) = self.title.as_ref() {
2526            return title.into();
2527        }
2528
2529        if let Some(buffer) = self.as_singleton() {
2530            let buffer = buffer.read(cx);
2531
2532            if let Some(file) = buffer.file() {
2533                return file.file_name(cx).into();
2534            }
2535
2536            if let Some(title) = self.buffer_content_title(buffer) {
2537                return title;
2538            }
2539        };
2540
2541        "untitled".into()
2542    }
2543
2544    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2545        let mut is_leading_whitespace = true;
2546        let mut count = 0;
2547        let mut prev_was_space = false;
2548        let mut title = String::new();
2549
2550        for ch in buffer.snapshot().chars() {
2551            if is_leading_whitespace && ch.is_whitespace() {
2552                continue;
2553            }
2554
2555            is_leading_whitespace = false;
2556
2557            if ch == '\n' || count >= 40 {
2558                break;
2559            }
2560
2561            if ch.is_whitespace() {
2562                if !prev_was_space {
2563                    title.push(' ');
2564                    count += 1;
2565                    prev_was_space = true;
2566                }
2567            } else {
2568                title.push(ch);
2569                count += 1;
2570                prev_was_space = false;
2571            }
2572        }
2573
2574        let title = title.trim_end().to_string();
2575
2576        if title.is_empty() {
2577            return None;
2578        }
2579
2580        Some(title.into())
2581    }
2582
2583    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2584        self.title = Some(title);
2585        cx.notify();
2586    }
2587
2588    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2589    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2590        for buffer_state in self.buffers.values() {
2591            buffer_state
2592                .buffer
2593                .update(cx, |buffer, _cx| buffer.refresh_preview());
2594        }
2595    }
2596
2597    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2598    pub fn preserve_preview(&self, cx: &App) -> bool {
2599        self.buffers
2600            .values()
2601            .all(|state| state.buffer.read(cx).preserve_preview())
2602    }
2603
2604    #[cfg(any(test, feature = "test-support"))]
2605    pub fn is_parsing(&self, cx: &App) -> bool {
2606        self.as_singleton().unwrap().read(cx).is_parsing()
2607    }
2608
2609    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2610        let buffer_id = diff.read(cx).buffer_id;
2611
2612        if let Some(existing_diff) = self.diff_for(buffer_id)
2613            && diff.entity_id() == existing_diff.entity_id()
2614        {
2615            return;
2616        }
2617
2618        self.buffer_diff_changed(
2619            diff.clone(),
2620            text::Anchor::min_max_range_for_buffer(buffer_id),
2621            cx,
2622        );
2623        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2624    }
2625
2626    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2627        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2628        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2629        self.snapshot.get_mut().has_inverted_diff = true;
2630        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2631        self.diffs
2632            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2633    }
2634
2635    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2636        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2637    }
2638
2639    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2640        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2641    }
2642
2643    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2644        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2645    }
2646
2647    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2648        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2649        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2650    }
2651
2652    pub fn all_diff_hunks_expanded(&self) -> bool {
2653        self.snapshot.borrow().all_diff_hunks_expanded
2654    }
2655
2656    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2657        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2658        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2659    }
2660
2661    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2662        self.snapshot.get_mut().show_deleted_hunks = show;
2663        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2664    }
2665
2666    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2667        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2668    }
2669
2670    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2671        self.read(cx)
2672            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2673            .nth(1)
2674            .is_some()
2675    }
2676
2677    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2678        let snapshot = self.read(cx);
2679        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2680        let offset_range = range.to_offset(&snapshot);
2681        cursor.seek(&offset_range.start, Bias::Left);
2682        while let Some(item) = cursor.item() {
2683            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2684                break;
2685            }
2686            if item.hunk_info().is_some() {
2687                return true;
2688            }
2689            cursor.next();
2690        }
2691        false
2692    }
2693
2694    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2695        let snapshot = self.read(cx);
2696        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2697        for range in ranges {
2698            let range = range.to_point(&snapshot);
2699            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2700            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2701                .min(snapshot.len());
2702            cursor.seek(&start, Bias::Right);
2703            while let Some(item) = cursor.item() {
2704                if *cursor.start() >= end {
2705                    break;
2706                }
2707                if item.hunk_info().is_some() {
2708                    return true;
2709                }
2710                cursor.next();
2711            }
2712        }
2713        false
2714    }
2715
2716    pub fn expand_or_collapse_diff_hunks_inner(
2717        &mut self,
2718        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2719        expand: bool,
2720        cx: &mut Context<Self>,
2721    ) {
2722        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2723            return;
2724        }
2725        self.sync_mut(cx);
2726        let mut snapshot = self.snapshot.get_mut();
2727        let mut excerpt_edits = Vec::new();
2728        let mut last_hunk_row = None;
2729        for (range, end_excerpt_id) in ranges {
2730            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2731                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2732                    continue;
2733                }
2734                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2735                    continue;
2736                }
2737                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2738                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2739                let start = snapshot.excerpt_offset_for_anchor(&start);
2740                let end = snapshot.excerpt_offset_for_anchor(&end);
2741                last_hunk_row = Some(diff_hunk.row_range.start);
2742                excerpt_edits.push(text::Edit {
2743                    old: start..end,
2744                    new: start..end,
2745                });
2746            }
2747        }
2748
2749        let edits = Self::sync_diff_transforms(
2750            &mut snapshot,
2751            excerpt_edits,
2752            DiffChangeKind::ExpandOrCollapseHunks { expand },
2753        );
2754        if !edits.is_empty() {
2755            self.subscriptions.publish(edits);
2756        }
2757        cx.emit(Event::DiffHunksToggled);
2758        cx.emit(Event::Edited {
2759            edited_buffer: None,
2760        });
2761    }
2762
2763    pub fn expand_or_collapse_diff_hunks(
2764        &mut self,
2765        ranges: Vec<Range<Anchor>>,
2766        expand: bool,
2767        cx: &mut Context<Self>,
2768    ) {
2769        let snapshot = self.snapshot.borrow().clone();
2770        let ranges = ranges.iter().map(move |range| {
2771            let end_excerpt_id = range.end.excerpt_id;
2772            let range = range.to_point(&snapshot);
2773            let mut peek_end = range.end;
2774            if range.end.row < snapshot.max_row().0 {
2775                peek_end = Point::new(range.end.row + 1, 0);
2776            };
2777            (range.start..peek_end, end_excerpt_id)
2778        });
2779        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2780    }
2781
2782    pub fn resize_excerpt(
2783        &mut self,
2784        id: ExcerptId,
2785        range: Range<text::Anchor>,
2786        cx: &mut Context<Self>,
2787    ) {
2788        self.sync_mut(cx);
2789
2790        let mut snapshot = self.snapshot.get_mut();
2791        let locator = snapshot.excerpt_locator_for_id(id);
2792        let mut new_excerpts = SumTree::default();
2793        let mut cursor = snapshot
2794            .excerpts
2795            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2796        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2797
2798        let prefix = cursor.slice(&Some(locator), Bias::Left);
2799        new_excerpts.append(prefix, ());
2800
2801        let mut excerpt = cursor.item().unwrap().clone();
2802        let old_text_len = excerpt.text_summary.len;
2803
2804        excerpt.range.context.start = range.start;
2805        excerpt.range.context.end = range.end;
2806        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2807
2808        excerpt.text_summary = excerpt
2809            .buffer
2810            .text_summary_for_range(excerpt.range.context.clone());
2811
2812        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2813        let old_start_offset = cursor.start().1;
2814        let new_text_len = excerpt.text_summary.len;
2815        let edit = Edit {
2816            old: old_start_offset..old_start_offset + old_text_len,
2817            new: new_start_offset..new_start_offset + new_text_len,
2818        };
2819
2820        if let Some(last_edit) = edits.last_mut() {
2821            if last_edit.old.end == edit.old.start {
2822                last_edit.old.end = edit.old.end;
2823                last_edit.new.end = edit.new.end;
2824            } else {
2825                edits.push(edit);
2826            }
2827        } else {
2828            edits.push(edit);
2829        }
2830
2831        new_excerpts.push(excerpt, ());
2832
2833        cursor.next();
2834
2835        new_excerpts.append(cursor.suffix(), ());
2836
2837        drop(cursor);
2838        snapshot.excerpts = new_excerpts;
2839
2840        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2841        if !edits.is_empty() {
2842            self.subscriptions.publish(edits);
2843        }
2844        cx.emit(Event::Edited {
2845            edited_buffer: None,
2846        });
2847        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2848        cx.notify();
2849    }
2850
2851    pub fn expand_excerpts(
2852        &mut self,
2853        ids: impl IntoIterator<Item = ExcerptId>,
2854        line_count: u32,
2855        direction: ExpandExcerptDirection,
2856        cx: &mut Context<Self>,
2857    ) {
2858        if line_count == 0 {
2859            return;
2860        }
2861        self.sync_mut(cx);
2862        if !self.excerpts_by_path.is_empty() {
2863            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2864            return;
2865        }
2866        let mut snapshot = self.snapshot.get_mut();
2867
2868        let ids = ids.into_iter().collect::<Vec<_>>();
2869        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2870        let mut new_excerpts = SumTree::default();
2871        let mut cursor = snapshot
2872            .excerpts
2873            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2874        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2875
2876        for locator in &locators {
2877            let prefix = cursor.slice(&Some(locator), Bias::Left);
2878            new_excerpts.append(prefix, ());
2879
2880            let mut excerpt = cursor.item().unwrap().clone();
2881            let old_text_len = excerpt.text_summary.len;
2882
2883            let up_line_count = if direction.should_expand_up() {
2884                line_count
2885            } else {
2886                0
2887            };
2888
2889            let start_row = excerpt
2890                .range
2891                .context
2892                .start
2893                .to_point(&excerpt.buffer)
2894                .row
2895                .saturating_sub(up_line_count);
2896            let start_point = Point::new(start_row, 0);
2897            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2898
2899            let down_line_count = if direction.should_expand_down() {
2900                line_count
2901            } else {
2902                0
2903            };
2904
2905            let mut end_point = excerpt.buffer.clip_point(
2906                excerpt.range.context.end.to_point(&excerpt.buffer)
2907                    + Point::new(down_line_count, 0),
2908                Bias::Left,
2909            );
2910            end_point.column = excerpt.buffer.line_len(end_point.row);
2911            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2912            excerpt.max_buffer_row = end_point.row;
2913
2914            excerpt.text_summary = excerpt
2915                .buffer
2916                .text_summary_for_range(excerpt.range.context.clone());
2917
2918            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2919            let old_start_offset = cursor.start().1;
2920            let new_text_len = excerpt.text_summary.len;
2921            let edit = Edit {
2922                old: old_start_offset..old_start_offset + old_text_len,
2923                new: new_start_offset..new_start_offset + new_text_len,
2924            };
2925
2926            if let Some(last_edit) = edits.last_mut() {
2927                if last_edit.old.end == edit.old.start {
2928                    last_edit.old.end = edit.old.end;
2929                    last_edit.new.end = edit.new.end;
2930                } else {
2931                    edits.push(edit);
2932                }
2933            } else {
2934                edits.push(edit);
2935            }
2936
2937            new_excerpts.push(excerpt, ());
2938
2939            cursor.next();
2940        }
2941
2942        new_excerpts.append(cursor.suffix(), ());
2943
2944        drop(cursor);
2945        snapshot.excerpts = new_excerpts;
2946
2947        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2948        if !edits.is_empty() {
2949            self.subscriptions.publish(edits);
2950        }
2951        cx.emit(Event::Edited {
2952            edited_buffer: None,
2953        });
2954        cx.emit(Event::ExcerptsExpanded { ids });
2955        cx.notify();
2956    }
2957
2958    #[ztracing::instrument(skip_all)]
2959    fn sync(&self, cx: &App) {
2960        let changed = self.buffer_changed_since_sync.replace(false);
2961        if !changed {
2962            return;
2963        }
2964        let edits = Self::sync_from_buffer_changes(
2965            &mut self.snapshot.borrow_mut(),
2966            &self.buffers,
2967            &self.diffs,
2968            cx,
2969        );
2970        if !edits.is_empty() {
2971            self.subscriptions.publish(edits);
2972        }
2973    }
2974
2975    fn sync_mut(&mut self, cx: &App) {
2976        let changed = self.buffer_changed_since_sync.replace(false);
2977        if !changed {
2978            return;
2979        }
2980        let edits =
2981            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2982
2983        if !edits.is_empty() {
2984            self.subscriptions.publish(edits);
2985        }
2986    }
2987
2988    fn sync_from_buffer_changes(
2989        snapshot: &mut MultiBufferSnapshot,
2990        buffers: &BTreeMap<BufferId, BufferState>,
2991        diffs: &HashMap<BufferId, DiffState>,
2992        cx: &App,
2993    ) -> Vec<Edit<MultiBufferOffset>> {
2994        let MultiBufferSnapshot {
2995            excerpts,
2996            diffs: buffer_diff,
2997            diff_transforms: _,
2998            non_text_state_update_count,
2999            edit_count,
3000            is_dirty,
3001            has_deleted_file,
3002            has_conflict,
3003            has_inverted_diff: _,
3004            singleton: _,
3005            excerpt_ids: _,
3006            replaced_excerpts: _,
3007            trailing_excerpt_update_count: _,
3008            all_diff_hunks_expanded: _,
3009            show_deleted_hunks: _,
3010            use_extended_diff_range: _,
3011            show_headers: _,
3012        } = snapshot;
3013        *is_dirty = false;
3014        *has_deleted_file = false;
3015        *has_conflict = false;
3016
3017        if !diffs.is_empty() {
3018            let mut diffs_to_add = Vec::new();
3019            for (id, diff) in diffs {
3020                if diff.is_inverted || buffer_diff.get(id).is_none() {
3021                    if diffs_to_add.capacity() == 0 {
3022                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3023                        // meaning re-allocations will be fairly expensive
3024                        diffs_to_add.reserve(diffs.len());
3025                    }
3026                    diffs_to_add.push((*id, diff.snapshot(cx)));
3027                }
3028            }
3029            buffer_diff.extend(diffs_to_add);
3030        }
3031
3032        let mut excerpts_to_edit = Vec::new();
3033        let mut non_text_state_updated = false;
3034        let mut edited = false;
3035        for buffer_state in buffers.values() {
3036            let buffer = buffer_state.buffer.read(cx);
3037            let version = buffer.version();
3038            let non_text_state_update_count = buffer.non_text_state_update_count();
3039
3040            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3041            let buffer_non_text_state_updated =
3042                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3043            if buffer_edited || buffer_non_text_state_updated {
3044                *buffer_state.last_version.borrow_mut() = version;
3045                buffer_state
3046                    .last_non_text_state_update_count
3047                    .set(non_text_state_update_count);
3048                excerpts_to_edit.extend(
3049                    buffer_state
3050                        .excerpts
3051                        .iter()
3052                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3053                );
3054            }
3055
3056            edited |= buffer_edited;
3057            non_text_state_updated |= buffer_non_text_state_updated;
3058            *is_dirty |= buffer.is_dirty();
3059            *has_deleted_file |= buffer
3060                .file()
3061                .is_some_and(|file| file.disk_state().is_deleted());
3062            *has_conflict |= buffer.has_conflict();
3063        }
3064        if edited {
3065            *edit_count += 1;
3066        }
3067        if non_text_state_updated {
3068            *non_text_state_update_count += 1;
3069        }
3070
3071        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3072
3073        let mut edits = Vec::new();
3074        let mut new_excerpts = SumTree::default();
3075        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3076
3077        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3078            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3079            let old_excerpt = cursor.item().unwrap();
3080            let buffer = buffer.read(cx);
3081            let buffer_id = buffer.remote_id();
3082            let mut new_excerpt;
3083            if buffer_edited {
3084                edits.extend(
3085                    buffer
3086                        .edits_since_in_range::<usize>(
3087                            old_excerpt.buffer.version(),
3088                            old_excerpt.range.context.clone(),
3089                        )
3090                        .map(|edit| {
3091                            let excerpt_old_start = cursor.start().1;
3092                            let excerpt_new_start =
3093                                ExcerptDimension(new_excerpts.summary().text.len);
3094                            let old_start = excerpt_old_start + edit.old.start;
3095                            let old_end = excerpt_old_start + edit.old.end;
3096                            let new_start = excerpt_new_start + edit.new.start;
3097                            let new_end = excerpt_new_start + edit.new.end;
3098                            Edit {
3099                                old: old_start..old_end,
3100                                new: new_start..new_end,
3101                            }
3102                        }),
3103                );
3104
3105                new_excerpt = Excerpt::new(
3106                    old_excerpt.id,
3107                    locator.clone(),
3108                    buffer_id,
3109                    Arc::new(buffer.snapshot()),
3110                    old_excerpt.range.clone(),
3111                    old_excerpt.has_trailing_newline,
3112                );
3113            } else {
3114                new_excerpt = old_excerpt.clone();
3115                new_excerpt.buffer = Arc::new(buffer.snapshot());
3116            }
3117
3118            new_excerpts.push(new_excerpt, ());
3119            cursor.next();
3120        }
3121        new_excerpts.append(cursor.suffix(), ());
3122
3123        drop(cursor);
3124        *excerpts = new_excerpts;
3125
3126        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3127    }
3128
3129    fn sync_diff_transforms(
3130        snapshot: &mut MultiBufferSnapshot,
3131        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3132        change_kind: DiffChangeKind,
3133    ) -> Vec<Edit<MultiBufferOffset>> {
3134        if excerpt_edits.is_empty() {
3135            return vec![];
3136        }
3137
3138        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3139        let mut old_diff_transforms = snapshot
3140            .diff_transforms
3141            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3142        let mut new_diff_transforms = SumTree::default();
3143        let mut old_expanded_hunks = HashSet::default();
3144        let mut output_edits = Vec::new();
3145        let mut output_delta = 0_isize;
3146        let mut at_transform_boundary = true;
3147        let mut end_of_current_insert = None;
3148
3149        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3150        while let Some(edit) = excerpt_edits.next() {
3151            excerpts.seek_forward(&edit.new.start, Bias::Right);
3152            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3153                excerpts.prev();
3154            }
3155
3156            // Keep any transforms that are before the edit.
3157            if at_transform_boundary {
3158                at_transform_boundary = false;
3159                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3160                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3161                if let Some(transform) = old_diff_transforms.item()
3162                    && old_diff_transforms.end().0 == edit.old.start
3163                    && old_diff_transforms.start().0 < edit.old.start
3164                {
3165                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3166                    old_diff_transforms.next();
3167                }
3168            }
3169
3170            // Compute the start of the edit in output coordinates.
3171            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3172            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3173            let edit_new_start =
3174                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3175
3176            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3177                &edit,
3178                &mut excerpts,
3179                &mut old_diff_transforms,
3180                &mut new_diff_transforms,
3181                &mut end_of_current_insert,
3182                &mut old_expanded_hunks,
3183                snapshot,
3184                change_kind,
3185            );
3186
3187            // Compute the end of the edit in output coordinates.
3188            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3189            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3190            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3191            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3192            let output_edit = Edit {
3193                old: edit_old_start..edit_old_end,
3194                new: edit_new_start..edit_new_end,
3195            };
3196
3197            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3198            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3199            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3200                output_edits.push(output_edit);
3201            }
3202
3203            // If this is the last edit that intersects the current diff transform,
3204            // then recreate the content up to the end of this transform, to prepare
3205            // for reusing additional slices of the old transforms.
3206            if excerpt_edits
3207                .peek()
3208                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3209            {
3210                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3211                    && match old_diff_transforms.item() {
3212                        Some(DiffTransform::BufferContent {
3213                            inserted_hunk_info: Some(hunk),
3214                            ..
3215                        }) => excerpts.item().is_some_and(|excerpt| {
3216                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3217                                && diff.is_inverted
3218                            {
3219                                return true;
3220                            }
3221                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3222                        }),
3223                        _ => true,
3224                    };
3225
3226                let mut excerpt_offset = edit.new.end;
3227                if !keep_next_old_transform {
3228                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3229                    old_diff_transforms.next();
3230                }
3231
3232                old_expanded_hunks.clear();
3233                Self::push_buffer_content_transform(
3234                    snapshot,
3235                    &mut new_diff_transforms,
3236                    excerpt_offset,
3237                    end_of_current_insert,
3238                );
3239                at_transform_boundary = true;
3240            }
3241        }
3242
3243        // Keep any transforms that are after the last edit.
3244        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3245
3246        // Ensure there's always at least one buffer content transform.
3247        if new_diff_transforms.is_empty() {
3248            new_diff_transforms.push(
3249                DiffTransform::BufferContent {
3250                    summary: Default::default(),
3251                    inserted_hunk_info: None,
3252                },
3253                (),
3254            );
3255        }
3256
3257        drop(old_diff_transforms);
3258        drop(excerpts);
3259        snapshot.diff_transforms = new_diff_transforms;
3260        snapshot.edit_count += 1;
3261
3262        #[cfg(any(test, feature = "test-support"))]
3263        snapshot.check_invariants();
3264        output_edits
3265    }
3266
3267    fn recompute_diff_transforms_for_edit(
3268        edit: &Edit<ExcerptOffset>,
3269        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3270        old_diff_transforms: &mut Cursor<
3271            DiffTransform,
3272            Dimensions<ExcerptOffset, MultiBufferOffset>,
3273        >,
3274        new_diff_transforms: &mut SumTree<DiffTransform>,
3275        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3276        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3277        snapshot: &MultiBufferSnapshot,
3278        change_kind: DiffChangeKind,
3279    ) -> bool {
3280        log::trace!(
3281            "recomputing diff transform for edit {:?} => {:?}",
3282            edit.old.start..edit.old.end,
3283            edit.new.start..edit.new.end
3284        );
3285
3286        // Record which hunks were previously expanded.
3287        while let Some(item) = old_diff_transforms.item() {
3288            if let Some(hunk_info) = item.hunk_info() {
3289                log::trace!(
3290                    "previously expanded hunk at {:?}",
3291                    old_diff_transforms.start()
3292                );
3293                old_expanded_hunks.insert(hunk_info);
3294            }
3295            if old_diff_transforms.end().0 > edit.old.end {
3296                break;
3297            }
3298            old_diff_transforms.next();
3299        }
3300
3301        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3302        // For inverted diffs, hunks are always shown, so we can't skip this.
3303        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3304        if old_expanded_hunks.is_empty()
3305            && change_kind == DiffChangeKind::BufferEdited
3306            && !all_diff_hunks_expanded
3307            && !snapshot.has_inverted_diff
3308        {
3309            return false;
3310        }
3311
3312        // Visit each excerpt that intersects the edit.
3313        let mut did_expand_hunks = false;
3314        while let Some(excerpt) = excerpts.item() {
3315            // Recompute the expanded hunks in the portion of the excerpt that
3316            // intersects the edit.
3317            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3318                let buffer = &excerpt.buffer;
3319                let excerpt_start = *excerpts.start();
3320                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3321                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3322                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3323                let edit_buffer_start =
3324                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3325                let edit_buffer_end =
3326                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3327                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3328
3329                if diff.is_inverted {
3330                    for hunk in diff.hunks_intersecting_base_text_range(
3331                        edit_buffer_start..edit_buffer_end,
3332                        diff.original_buffer_snapshot(),
3333                    ) {
3334                        did_expand_hunks = true;
3335                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3336                        if hunk_buffer_range.start < excerpt_buffer_start {
3337                            log::trace!("skipping hunk that starts before excerpt");
3338                            continue;
3339                        }
3340                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3341                        let hunk_excerpt_start = excerpt_start
3342                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3343                        let hunk_excerpt_end = excerpt_end
3344                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3345                        Self::push_buffer_content_transform(
3346                            snapshot,
3347                            new_diff_transforms,
3348                            hunk_excerpt_start,
3349                            *end_of_current_insert,
3350                        );
3351                        if !hunk_buffer_range.is_empty() {
3352                            let hunk_info = DiffTransformHunkInfo {
3353                                excerpt_id: excerpt.id,
3354                                hunk_start_anchor: hunk.buffer_range.start,
3355                                hunk_secondary_status: hunk.secondary_status,
3356                                is_logically_deleted: true,
3357                            };
3358                            *end_of_current_insert =
3359                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3360                        }
3361                    }
3362                } else {
3363                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3364                        ..buffer.anchor_after(edit_buffer_end);
3365                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3366                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3367                            continue;
3368                        }
3369
3370                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3371                        if hunk_buffer_range.start < excerpt_buffer_start {
3372                            log::trace!("skipping hunk that starts before excerpt");
3373                            continue;
3374                        }
3375
3376                        let hunk_info = DiffTransformHunkInfo {
3377                            excerpt_id: excerpt.id,
3378                            hunk_start_anchor: hunk.buffer_range.start,
3379                            hunk_secondary_status: hunk.secondary_status,
3380                            is_logically_deleted: false,
3381                        };
3382
3383                        let hunk_excerpt_start = excerpt_start
3384                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3385                        let hunk_excerpt_end = excerpt_end
3386                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3387
3388                        Self::push_buffer_content_transform(
3389                            snapshot,
3390                            new_diff_transforms,
3391                            hunk_excerpt_start,
3392                            *end_of_current_insert,
3393                        );
3394
3395                        // For every existing hunk, determine if it was previously expanded
3396                        // and if it should currently be expanded.
3397                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3398                        let should_expand_hunk = match &change_kind {
3399                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3400                                was_previously_expanded || all_diff_hunks_expanded
3401                            }
3402                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3403                                let intersects = hunk_buffer_range.is_empty()
3404                                    || hunk_buffer_range.end > edit_buffer_start;
3405                                if *expand {
3406                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3407                                } else {
3408                                    !intersects
3409                                        && (was_previously_expanded || all_diff_hunks_expanded)
3410                                }
3411                            }
3412                            _ => was_previously_expanded || all_diff_hunks_expanded,
3413                        };
3414
3415                        if should_expand_hunk {
3416                            did_expand_hunks = true;
3417                            log::trace!(
3418                                "expanding hunk {:?}, excerpt:{:?}",
3419                                hunk_excerpt_start..hunk_excerpt_end,
3420                                excerpt.id
3421                            );
3422
3423                            if !hunk.diff_base_byte_range.is_empty()
3424                                && hunk_buffer_range.start >= edit_buffer_start
3425                                && hunk_buffer_range.start <= excerpt_buffer_end
3426                                && snapshot.show_deleted_hunks
3427                            {
3428                                let base_text = diff.base_text();
3429                                let mut text_cursor =
3430                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3431                                let mut base_text_summary = text_cursor
3432                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3433
3434                                let mut has_trailing_newline = false;
3435                                if base_text_summary.last_line_chars > 0 {
3436                                    base_text_summary += TextSummary::newline();
3437                                    has_trailing_newline = true;
3438                                }
3439
3440                                new_diff_transforms.push(
3441                                    DiffTransform::DeletedHunk {
3442                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3443                                        summary: base_text_summary,
3444                                        buffer_id: excerpt.buffer_id,
3445                                        hunk_info,
3446                                        has_trailing_newline,
3447                                    },
3448                                    (),
3449                                );
3450                            }
3451
3452                            if !hunk_buffer_range.is_empty() {
3453                                *end_of_current_insert =
3454                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3455                            }
3456                        }
3457                    }
3458                }
3459            }
3460
3461            if excerpts.end() <= edit.new.end {
3462                excerpts.next();
3463            } else {
3464                break;
3465            }
3466        }
3467
3468        did_expand_hunks || !old_expanded_hunks.is_empty()
3469    }
3470
3471    fn append_diff_transforms(
3472        new_transforms: &mut SumTree<DiffTransform>,
3473        subtree: SumTree<DiffTransform>,
3474    ) {
3475        if let Some(DiffTransform::BufferContent {
3476            inserted_hunk_info,
3477            summary,
3478        }) = subtree.first()
3479            && Self::extend_last_buffer_content_transform(
3480                new_transforms,
3481                *inserted_hunk_info,
3482                *summary,
3483            )
3484        {
3485            let mut cursor = subtree.cursor::<()>(());
3486            cursor.next();
3487            cursor.next();
3488            new_transforms.append(cursor.suffix(), ());
3489            return;
3490        }
3491        new_transforms.append(subtree, ());
3492    }
3493
3494    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3495        if let DiffTransform::BufferContent {
3496            inserted_hunk_info: inserted_hunk_anchor,
3497            summary,
3498        } = transform
3499            && Self::extend_last_buffer_content_transform(
3500                new_transforms,
3501                inserted_hunk_anchor,
3502                summary,
3503            )
3504        {
3505            return;
3506        }
3507        new_transforms.push(transform, ());
3508    }
3509
3510    fn push_buffer_content_transform(
3511        old_snapshot: &MultiBufferSnapshot,
3512        new_transforms: &mut SumTree<DiffTransform>,
3513        end_offset: ExcerptOffset,
3514        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3515    ) {
3516        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3517            (end_offset.min(insertion_end_offset), Some(hunk_info))
3518        });
3519        let unchanged_region = [(end_offset, None)];
3520
3521        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3522        {
3523            let start_offset = new_transforms.summary().excerpt_len();
3524            if end_offset <= start_offset {
3525                continue;
3526            }
3527            let summary_to_add = old_snapshot
3528                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3529
3530            if !Self::extend_last_buffer_content_transform(
3531                new_transforms,
3532                inserted_hunk_info,
3533                summary_to_add,
3534            ) {
3535                new_transforms.push(
3536                    DiffTransform::BufferContent {
3537                        summary: summary_to_add,
3538                        inserted_hunk_info,
3539                    },
3540                    (),
3541                )
3542            }
3543        }
3544    }
3545
3546    fn extend_last_buffer_content_transform(
3547        new_transforms: &mut SumTree<DiffTransform>,
3548        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3549        summary_to_add: MBTextSummary,
3550    ) -> bool {
3551        let mut did_extend = false;
3552        new_transforms.update_last(
3553            |last_transform| {
3554                if let DiffTransform::BufferContent {
3555                    summary,
3556                    inserted_hunk_info: inserted_hunk_anchor,
3557                } = last_transform
3558                    && *inserted_hunk_anchor == new_inserted_hunk_info
3559                {
3560                    *summary += summary_to_add;
3561                    did_extend = true;
3562                }
3563            },
3564            (),
3565        );
3566        did_extend
3567    }
3568}
3569
3570fn build_excerpt_ranges(
3571    ranges: impl IntoIterator<Item = Range<Point>>,
3572    context_line_count: u32,
3573    buffer_snapshot: &BufferSnapshot,
3574) -> Vec<ExcerptRange<Point>> {
3575    ranges
3576        .into_iter()
3577        .map(|range| {
3578            let start_row = range.start.row.saturating_sub(context_line_count);
3579            let start = Point::new(start_row, 0);
3580            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3581            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3582            ExcerptRange {
3583                context: start..end,
3584                primary: range,
3585            }
3586        })
3587        .collect()
3588}
3589
3590#[cfg(any(test, feature = "test-support"))]
3591impl MultiBuffer {
3592    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3593        let buffer = cx.new(|cx| Buffer::local(text, cx));
3594        cx.new(|cx| Self::singleton(buffer, cx))
3595    }
3596
3597    pub fn build_multi<const COUNT: usize>(
3598        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3599        cx: &mut gpui::App,
3600    ) -> Entity<Self> {
3601        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3602        for (text, ranges) in excerpts {
3603            let buffer = cx.new(|cx| Buffer::local(text, cx));
3604            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3605            multi.update(cx, |multi, cx| {
3606                multi.push_excerpts(buffer, excerpt_ranges, cx)
3607            });
3608        }
3609
3610        multi
3611    }
3612
3613    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3614        cx.new(|cx| Self::singleton(buffer, cx))
3615    }
3616
3617    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3618        cx.new(|cx| {
3619            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3620            let mutation_count = rng.random_range(1..=5);
3621            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3622            multibuffer
3623        })
3624    }
3625
3626    pub fn randomly_edit(
3627        &mut self,
3628        rng: &mut impl rand::Rng,
3629        edit_count: usize,
3630        cx: &mut Context<Self>,
3631    ) {
3632        use util::RandomCharIter;
3633
3634        let snapshot = self.read(cx);
3635        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3636        let mut last_end = None;
3637        for _ in 0..edit_count {
3638            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3639                break;
3640            }
3641
3642            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3643            let end =
3644                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3645            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3646            last_end = Some(end);
3647
3648            let mut range = start..end;
3649            if rng.random_bool(0.2) {
3650                mem::swap(&mut range.start, &mut range.end);
3651            }
3652
3653            let new_text_len = rng.random_range(0..10);
3654            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3655
3656            edits.push((range, new_text.into()));
3657        }
3658        log::info!("mutating multi-buffer with {:?}", edits);
3659        drop(snapshot);
3660
3661        self.edit(edits, None, cx);
3662    }
3663
3664    pub fn randomly_edit_excerpts(
3665        &mut self,
3666        rng: &mut impl rand::Rng,
3667        mutation_count: usize,
3668        cx: &mut Context<Self>,
3669    ) {
3670        use rand::prelude::*;
3671        use std::env;
3672        use util::RandomCharIter;
3673
3674        let max_excerpts = env::var("MAX_EXCERPTS")
3675            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3676            .unwrap_or(5);
3677
3678        let mut buffers = Vec::new();
3679        for _ in 0..mutation_count {
3680            if rng.random_bool(0.05) {
3681                log::info!("Clearing multi-buffer");
3682                self.clear(cx);
3683                continue;
3684            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3685                let ids = self.excerpt_ids();
3686                let mut excerpts = HashSet::default();
3687                for _ in 0..rng.random_range(0..ids.len()) {
3688                    excerpts.extend(ids.choose(rng).copied());
3689                }
3690
3691                let line_count = rng.random_range(0..5);
3692
3693                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3694
3695                self.expand_excerpts(
3696                    excerpts.iter().cloned(),
3697                    line_count,
3698                    ExpandExcerptDirection::UpAndDown,
3699                    cx,
3700                );
3701                continue;
3702            }
3703
3704            let excerpt_ids = self.excerpt_ids();
3705            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3706                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3707                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3708                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3709                    let buffer = buffers.last().unwrap().read(cx);
3710                    log::info!(
3711                        "Creating new buffer {} with text: {:?}",
3712                        buffer.remote_id(),
3713                        buffer.text()
3714                    );
3715                    buffers.last().unwrap().clone()
3716                } else {
3717                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3718                };
3719
3720                let buffer = buffer_handle.read(cx);
3721                let buffer_text = buffer.text();
3722                let ranges = (0..rng.random_range(0..5))
3723                    .map(|_| {
3724                        let end_ix =
3725                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3726                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3727                        ExcerptRange::new(start_ix..end_ix)
3728                    })
3729                    .collect::<Vec<_>>();
3730                log::info!(
3731                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3732                    buffer_handle.read(cx).remote_id(),
3733                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3734                    ranges
3735                        .iter()
3736                        .map(|r| &buffer_text[r.context.clone()])
3737                        .collect::<Vec<_>>()
3738                );
3739
3740                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3741                log::info!("Inserted with ids: {:?}", excerpt_id);
3742            } else {
3743                let remove_count = rng.random_range(1..=excerpt_ids.len());
3744                let mut excerpts_to_remove = excerpt_ids
3745                    .choose_multiple(rng, remove_count)
3746                    .cloned()
3747                    .collect::<Vec<_>>();
3748                let snapshot = self.snapshot.borrow();
3749                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3750                drop(snapshot);
3751                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3752                self.remove_excerpts(excerpts_to_remove, cx);
3753            }
3754        }
3755    }
3756
3757    pub fn randomly_mutate(
3758        &mut self,
3759        rng: &mut impl rand::Rng,
3760        mutation_count: usize,
3761        cx: &mut Context<Self>,
3762    ) {
3763        use rand::prelude::*;
3764
3765        if rng.random_bool(0.7) || self.singleton {
3766            let buffer = self
3767                .buffers
3768                .values()
3769                .choose(rng)
3770                .map(|state| state.buffer.clone());
3771
3772            if let Some(buffer) = buffer {
3773                buffer.update(cx, |buffer, cx| {
3774                    if rng.random() {
3775                        buffer.randomly_edit(rng, mutation_count, cx);
3776                    } else {
3777                        buffer.randomly_undo_redo(rng, cx);
3778                    }
3779                });
3780            } else {
3781                self.randomly_edit(rng, mutation_count, cx);
3782            }
3783        } else {
3784            self.randomly_edit_excerpts(rng, mutation_count, cx);
3785        }
3786
3787        self.check_invariants(cx);
3788    }
3789
3790    fn check_invariants(&self, cx: &App) {
3791        self.read(cx).check_invariants();
3792    }
3793}
3794
3795impl EventEmitter<Event> for MultiBuffer {}
3796
3797impl MultiBufferSnapshot {
3798    pub fn text(&self) -> String {
3799        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3800            .map(|chunk| chunk.text)
3801            .collect()
3802    }
3803
3804    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3805        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3806            .flat_map(|c| c.chars().rev())
3807    }
3808
3809    fn reversed_chunks_in_range(
3810        &self,
3811        range: Range<MultiBufferOffset>,
3812    ) -> ReversedMultiBufferChunks<'_> {
3813        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3814        cursor.seek(&range.end);
3815        let current_chunks = cursor.region().as_ref().map(|region| {
3816            let start_overshoot = range.start.saturating_sub(region.range.start);
3817            let end_overshoot = range.end - region.range.start;
3818            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3819            let start = region.buffer_range.start + start_overshoot;
3820            region.buffer.reversed_chunks_in_range(start..end)
3821        });
3822        ReversedMultiBufferChunks {
3823            cursor,
3824            current_chunks,
3825            start: range.start,
3826            offset: range.end,
3827        }
3828    }
3829
3830    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3831        let offset = position.to_offset(self);
3832        self.text_for_range(offset..self.len())
3833            .flat_map(|chunk| chunk.chars())
3834    }
3835
3836    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3837        self.chunks(range, false).map(|chunk| chunk.text)
3838    }
3839
3840    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3841        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3842            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3843    }
3844
3845    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3846    where
3847        T: ToOffset,
3848    {
3849        let position = position.to_offset(self);
3850        position == self.clip_offset(position, Bias::Left)
3851            && self
3852                .bytes_in_range(position..self.len())
3853                .flatten()
3854                .copied()
3855                .take(needle.len())
3856                .eq(needle.bytes())
3857    }
3858
3859    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3860        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3861    }
3862
3863    pub fn diff_hunks_in_range<T: ToPoint>(
3864        &self,
3865        range: Range<T>,
3866    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3867        let query_range = range.start.to_point(self)..range.end.to_point(self);
3868        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3869            let diff = self.diffs.get(&buffer.remote_id())?;
3870            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3871                if diff.is_inverted {
3872                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3873                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3874                    Box::new(
3875                        diff.hunks_intersecting_base_text_range(
3876                            buffer_start..buffer_end,
3877                            diff.original_buffer_snapshot(),
3878                        )
3879                        .map(move |hunk| (hunk, buffer, true)),
3880                    )
3881                } else {
3882                    let buffer_start = buffer.anchor_before(buffer_range.start);
3883                    let buffer_end = buffer.anchor_after(buffer_range.end);
3884                    Box::new(
3885                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3886                            .map(move |hunk| (hunk, buffer, false)),
3887                    )
3888                };
3889            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3890                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3891                    return None;
3892                }
3893                let range = if is_inverted {
3894                    hunk.diff_base_byte_range.to_point(&buffer)
3895                } else {
3896                    hunk.range.clone()
3897                };
3898                Some((range, (hunk, is_inverted)))
3899            }))
3900        })
3901        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3902            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3903            {
3904                return None;
3905            }
3906            let end_row = if range.end.column == 0 {
3907                range.end.row
3908            } else {
3909                range.end.row + 1
3910            };
3911
3912            let word_diffs =
3913                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3914                    .then(|| {
3915                        let mut word_diffs = Vec::new();
3916
3917                        if self.show_deleted_hunks || is_inverted {
3918                            let hunk_start_offset = if is_inverted {
3919                                Anchor::in_buffer(
3920                                    excerpt.id,
3921                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3922                                )
3923                                .to_offset(self)
3924                            } else {
3925                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3926                                    .to_offset(self)
3927                            };
3928
3929                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3930                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3931                            }));
3932                        }
3933
3934                        if !is_inverted {
3935                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3936                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3937                            }));
3938                        }
3939                        word_diffs
3940                    })
3941                    .unwrap_or_default();
3942
3943            let buffer_range = if is_inverted {
3944                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3945                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3946            } else {
3947                hunk.buffer_range.clone()
3948            };
3949            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3950                DiffHunkStatusKind::Deleted
3951            } else if hunk.diff_base_byte_range.is_empty() {
3952                DiffHunkStatusKind::Added
3953            } else {
3954                DiffHunkStatusKind::Modified
3955            };
3956            Some(MultiBufferDiffHunk {
3957                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3958                buffer_id: excerpt.buffer_id,
3959                excerpt_id: excerpt.id,
3960                buffer_range,
3961                word_diffs,
3962                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3963                    ..BufferOffset(hunk.diff_base_byte_range.end),
3964                status: DiffHunkStatus {
3965                    kind: status_kind,
3966                    secondary: hunk.secondary_status,
3967                },
3968            })
3969        })
3970    }
3971
3972    fn excerpts_for_range<T: ToOffset>(
3973        &self,
3974        range: Range<T>,
3975    ) -> impl Iterator<Item = &Excerpt> + '_ {
3976        let range = range.start.to_offset(self)..range.end.to_offset(self);
3977        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3978        cursor.seek(&range.start);
3979        std::iter::from_fn(move || {
3980            let region = cursor.region()?;
3981            if region.range.start > range.end
3982                || region.range.start == range.end && region.range.start > range.start
3983            {
3984                return None;
3985            }
3986            let excerpt = region.excerpt;
3987            cursor.next_excerpt_forwards();
3988            Some(excerpt)
3989        })
3990    }
3991
3992    pub fn excerpt_ids_for_range<T: ToOffset>(
3993        &self,
3994        range: Range<T>,
3995    ) -> impl Iterator<Item = ExcerptId> + '_ {
3996        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3997    }
3998
3999    pub fn buffer_ids_for_range<T: ToOffset>(
4000        &self,
4001        range: Range<T>,
4002    ) -> impl Iterator<Item = BufferId> + '_ {
4003        self.excerpts_for_range(range)
4004            .map(|excerpt| excerpt.buffer_id)
4005    }
4006
4007    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4008        &self,
4009        ranges: impl Iterator<Item = Range<T>>,
4010    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4011        ranges.flat_map(|range| {
4012            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4013                .into_iter()
4014        })
4015    }
4016
4017    pub fn range_to_buffer_ranges<R, T>(
4018        &self,
4019        range: R,
4020    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4021    where
4022        R: RangeBounds<T>,
4023        T: ToOffset,
4024    {
4025        self.range_to_buffer_ranges_with_context(range)
4026            .into_iter()
4027            .map(|(buffer, range, id, _context)| (buffer, range, id))
4028            .collect()
4029    }
4030
4031    pub fn range_to_buffer_ranges_with_context<R, T>(
4032        &self,
4033        range: R,
4034    ) -> Vec<(
4035        &BufferSnapshot,
4036        Range<BufferOffset>,
4037        ExcerptId,
4038        Range<text::Anchor>,
4039    )>
4040    where
4041        R: RangeBounds<T>,
4042        T: ToOffset,
4043    {
4044        let start = match range.start_bound() {
4045            Bound::Included(start) => start.to_offset(self),
4046            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4047            Bound::Unbounded => MultiBufferOffset::ZERO,
4048        };
4049        let end_bound = match range.end_bound() {
4050            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4051            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4052            Bound::Unbounded => Bound::Unbounded,
4053        };
4054        let bounds = (Bound::Included(start), end_bound);
4055
4056        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4057        cursor.seek(&start);
4058
4059        let mut result: Vec<(
4060            &BufferSnapshot,
4061            Range<BufferOffset>,
4062            ExcerptId,
4063            Range<text::Anchor>,
4064        )> = Vec::new();
4065        while let Some(region) = cursor.region() {
4066            let dominated_by_end_bound = match end_bound {
4067                Bound::Included(end) => region.range.start > end,
4068                Bound::Excluded(end) => region.range.start >= end,
4069                Bound::Unbounded => false,
4070            };
4071            if dominated_by_end_bound {
4072                break;
4073            }
4074            if region.is_main_buffer {
4075                let start_overshoot = start.saturating_sub(region.range.start);
4076                let end_offset = match end_bound {
4077                    Bound::Included(end) | Bound::Excluded(end) => end,
4078                    Bound::Unbounded => region.range.end,
4079                };
4080                let end_overshoot = end_offset.saturating_sub(region.range.start);
4081                let start = region
4082                    .buffer_range
4083                    .end
4084                    .min(region.buffer_range.start + start_overshoot);
4085                let end = region
4086                    .buffer_range
4087                    .end
4088                    .min(region.buffer_range.start + end_overshoot);
4089                let context = region.excerpt.range.context.clone();
4090                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4091                    *excerpt_id == region.excerpt.id && prev_range.end == start
4092                }) {
4093                    prev.1.end = end;
4094                } else {
4095                    result.push((region.buffer, start..end, region.excerpt.id, context));
4096                }
4097            }
4098            cursor.next();
4099        }
4100
4101        if let Some(excerpt) = cursor.excerpt() {
4102            let dominated_by_prev_excerpt =
4103                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4104            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4105                let excerpt_position = self.len();
4106                if bounds.contains(&excerpt_position) {
4107                    let buffer_offset =
4108                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4109                    let context = excerpt.range.context.clone();
4110                    result.push((
4111                        &excerpt.buffer,
4112                        buffer_offset..buffer_offset,
4113                        excerpt.id,
4114                        context,
4115                    ));
4116                }
4117            }
4118        }
4119
4120        result
4121    }
4122
4123    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4124        &self,
4125        range: Range<T>,
4126    ) -> impl Iterator<
4127        Item = (
4128            &BufferSnapshot,
4129            Range<BufferOffset>,
4130            ExcerptId,
4131            Option<Anchor>,
4132        ),
4133    > + '_ {
4134        let start = range.start.to_offset(self);
4135        let end = range.end.to_offset(self);
4136
4137        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4138        cursor.seek(&start);
4139
4140        std::iter::from_fn(move || {
4141            let region = cursor.region()?;
4142            if region.range.start > end {
4143                return None;
4144            }
4145            let start_overshoot = start.saturating_sub(region.range.start);
4146            let end_overshoot = end.saturating_sub(region.range.start);
4147            let start = region
4148                .buffer_range
4149                .end
4150                .min(region.buffer_range.start + start_overshoot);
4151            let end = region
4152                .buffer_range
4153                .end
4154                .min(region.buffer_range.start + end_overshoot);
4155
4156            let region_excerpt_id = region.excerpt.id;
4157            let deleted_hunk_anchor = if region.is_main_buffer {
4158                None
4159            } else {
4160                Some(self.anchor_before(region.range.start))
4161            };
4162            let result = (
4163                region.buffer,
4164                start..end,
4165                region_excerpt_id,
4166                deleted_hunk_anchor,
4167            );
4168            cursor.next();
4169            Some(result)
4170        })
4171    }
4172
4173    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4174    /// coordinates.
4175    ///
4176    /// The given callback will be called for every excerpt intersecting the given range. It will
4177    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4178    /// The callback should return an iterator of metadata items from that buffer, each paired
4179    /// with a buffer range.
4180    ///
4181    /// The returned iterator yields each of these metadata items, paired with its range in
4182    /// multi-buffer coordinates.
4183    fn lift_buffer_metadata<'a, MBD, M, I>(
4184        &'a self,
4185        query_range: Range<MBD>,
4186        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4187    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4188    where
4189        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4190        MBD: MultiBufferDimension
4191            + Ord
4192            + Sub<Output = MBD::TextDimension>
4193            + ops::Add<MBD::TextDimension, Output = MBD>
4194            + ops::AddAssign<MBD::TextDimension>,
4195        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4196            + ops::Add<Output = MBD::TextDimension>
4197            + AddAssign<MBD::TextDimension>
4198            + Ord,
4199    {
4200        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4201        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4202
4203        // Find the excerpt and buffer offset where the given range ends.
4204        cursor.seek(&query_range.end);
4205        let mut range_end = None;
4206        while let Some(region) = cursor.region() {
4207            if region.is_main_buffer {
4208                let mut buffer_end = region.buffer_range.start;
4209                let overshoot = if query_range.end > region.range.start {
4210                    query_range.end - region.range.start
4211                } else {
4212                    <MBD::TextDimension>::default()
4213                };
4214                buffer_end = buffer_end + overshoot;
4215                range_end = Some((region.excerpt.id, buffer_end));
4216                break;
4217            }
4218            cursor.next();
4219        }
4220
4221        cursor.seek(&query_range.start);
4222
4223        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4224            && region.range.start > MBD::default()
4225        {
4226            cursor.prev()
4227        } else if let Some(region) = cursor.region()
4228            && region.is_main_buffer
4229            && region.diff_hunk_status.is_some()
4230        {
4231            cursor.prev();
4232            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4233                cursor.next();
4234            }
4235        }
4236
4237        iter::from_fn(move || {
4238            loop {
4239                let excerpt = cursor.excerpt()?;
4240
4241                // If we have already retrieved metadata for this excerpt, continue to use it.
4242                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4243                    .as_mut()
4244                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4245                {
4246                    Some(metadata)
4247                }
4248                // Otherwise, compute the intersection of the input range with the excerpt's range,
4249                // and retrieve the metadata for the resulting range.
4250                else {
4251                    let region = cursor.region()?;
4252                    let mut buffer_start;
4253                    if region.is_main_buffer {
4254                        buffer_start = region.buffer_range.start;
4255                        if query_range.start > region.range.start {
4256                            let overshoot = query_range.start - region.range.start;
4257                            buffer_start = buffer_start + overshoot;
4258                        }
4259                        buffer_start = buffer_start.min(region.buffer_range.end);
4260                    } else {
4261                        buffer_start = cursor.main_buffer_position()?;
4262                    };
4263                    let mut buffer_end = excerpt
4264                        .range
4265                        .context
4266                        .end
4267                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4268                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4269                        && excerpt.id == end_excerpt_id
4270                    {
4271                        buffer_end = buffer_end.min(end_buffer_offset);
4272                    }
4273
4274                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4275                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4276                    })
4277                };
4278
4279                // Visit each metadata item.
4280                if let Some((metadata_buffer_range, metadata)) =
4281                    metadata_iter.and_then(Iterator::next)
4282                {
4283                    // Find the multibuffer regions that contain the start and end of
4284                    // the metadata item's range.
4285                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4286                        while let Some(region) = cursor.region() {
4287                            if (region.is_main_buffer
4288                                && (region.buffer_range.end >= metadata_buffer_range.start
4289                                    || cursor.is_at_end_of_excerpt()))
4290                                || (!region.is_main_buffer
4291                                    && region.buffer_range.start == metadata_buffer_range.start)
4292                            {
4293                                break;
4294                            }
4295                            cursor.next();
4296                        }
4297                    }
4298                    let start_region = cursor.region()?.clone();
4299                    while let Some(region) = cursor.region() {
4300                        if region.is_main_buffer
4301                            && (region.buffer_range.end > metadata_buffer_range.end
4302                                || cursor.is_at_end_of_excerpt())
4303                        {
4304                            break;
4305                        }
4306                        cursor.next();
4307                    }
4308                    let end_region = cursor.region();
4309
4310                    // Convert the metadata item's range into multibuffer coordinates.
4311                    let mut start_position = start_region.range.start;
4312                    let region_buffer_start = start_region.buffer_range.start;
4313                    if start_region.is_main_buffer
4314                        && metadata_buffer_range.start > region_buffer_start
4315                    {
4316                        start_position =
4317                            start_position + (metadata_buffer_range.start - region_buffer_start);
4318                        start_position = start_position.min(start_region.range.end);
4319                    }
4320
4321                    let mut end_position = self.max_position();
4322                    if let Some(end_region) = &end_region {
4323                        end_position = end_region.range.start;
4324                        debug_assert!(end_region.is_main_buffer);
4325                        let region_buffer_start = end_region.buffer_range.start;
4326                        if metadata_buffer_range.end > region_buffer_start {
4327                            end_position =
4328                                end_position + (metadata_buffer_range.end - region_buffer_start);
4329                        }
4330                        end_position = end_position.min(end_region.range.end);
4331                    }
4332
4333                    if start_position <= query_range.end && end_position >= query_range.start {
4334                        return Some((start_position..end_position, metadata, excerpt));
4335                    }
4336                }
4337                // When there are no more metadata items for this excerpt, move to the next excerpt.
4338                else {
4339                    current_excerpt_metadata.take();
4340                    if let Some((end_excerpt_id, _)) = range_end
4341                        && excerpt.id == end_excerpt_id
4342                    {
4343                        return None;
4344                    }
4345                    cursor.next_excerpt_forwards();
4346                }
4347            }
4348        })
4349    }
4350
4351    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4352        let offset = position.to_offset(self);
4353
4354        let mut cursor = self
4355            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4356            );
4357        cursor.seek(&DimensionPair {
4358            key: offset,
4359            value: None,
4360        });
4361        cursor.seek_to_start_of_current_excerpt();
4362        let excerpt = cursor.excerpt()?;
4363
4364        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4365        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4366        let current_position = self
4367            .anchor_before(offset)
4368            .text_anchor
4369            .to_offset(&excerpt.buffer);
4370
4371        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4372            if diff.is_inverted {
4373                for hunk in diff.hunks_intersecting_base_text_range_rev(
4374                    excerpt_start..excerpt_end,
4375                    diff.original_buffer_snapshot(),
4376                ) {
4377                    if hunk.diff_base_byte_range.end >= current_position {
4378                        continue;
4379                    }
4380                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4381                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4382                    return Some(MultiBufferRow(start.row));
4383                }
4384            } else {
4385                let excerpt_end = excerpt
4386                    .buffer
4387                    .anchor_before(excerpt_end.min(current_position));
4388                for hunk in diff.hunks_intersecting_range_rev(
4389                    excerpt.range.context.start..excerpt_end,
4390                    &excerpt.buffer,
4391                ) {
4392                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4393                    if hunk_end >= current_position {
4394                        continue;
4395                    }
4396                    let start =
4397                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4398                    return Some(MultiBufferRow(start.row));
4399                }
4400            }
4401        }
4402
4403        loop {
4404            cursor.prev_excerpt();
4405            let excerpt = cursor.excerpt()?;
4406
4407            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4408                continue;
4409            };
4410            if diff.is_inverted {
4411                let Some(hunk) = diff
4412                    .hunks_intersecting_base_text_range_rev(
4413                        excerpt.range.context.to_offset(&excerpt.buffer),
4414                        diff.original_buffer_snapshot(),
4415                    )
4416                    .next()
4417                else {
4418                    continue;
4419                };
4420                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4421                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4422                return Some(MultiBufferRow(start.row));
4423            } else {
4424                let Some(hunk) = diff
4425                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4426                    .next()
4427                else {
4428                    continue;
4429                };
4430                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4431                return Some(MultiBufferRow(start.row));
4432            }
4433        }
4434    }
4435
4436    pub fn has_diff_hunks(&self) -> bool {
4437        self.diffs.values().any(|diff| !diff.is_empty())
4438    }
4439
4440    pub fn is_inside_word<T: ToOffset>(
4441        &self,
4442        position: T,
4443        scope_context: Option<CharScopeContext>,
4444    ) -> bool {
4445        let position = position.to_offset(self);
4446        let classifier = self
4447            .char_classifier_at(position)
4448            .scope_context(scope_context);
4449        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4450        let prev_char_kind = self
4451            .reversed_chars_at(position)
4452            .next()
4453            .map(|c| classifier.kind(c));
4454        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4455    }
4456
4457    pub fn surrounding_word<T: ToOffset>(
4458        &self,
4459        start: T,
4460        scope_context: Option<CharScopeContext>,
4461    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4462        let mut start = start.to_offset(self);
4463        let mut end = start;
4464        let mut next_chars = self.chars_at(start).peekable();
4465        let mut prev_chars = self.reversed_chars_at(start).peekable();
4466
4467        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4468
4469        let word_kind = cmp::max(
4470            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4471            next_chars.peek().copied().map(|c| classifier.kind(c)),
4472        );
4473
4474        for ch in prev_chars {
4475            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4476                start -= ch.len_utf8();
4477            } else {
4478                break;
4479            }
4480        }
4481
4482        for ch in next_chars {
4483            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4484                end += ch.len_utf8();
4485            } else {
4486                break;
4487            }
4488        }
4489
4490        (start..end, word_kind)
4491    }
4492
4493    pub fn char_kind_before<T: ToOffset>(
4494        &self,
4495        start: T,
4496        scope_context: Option<CharScopeContext>,
4497    ) -> Option<CharKind> {
4498        let start = start.to_offset(self);
4499        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4500        self.reversed_chars_at(start)
4501            .next()
4502            .map(|ch| classifier.kind(ch))
4503    }
4504
4505    pub fn is_singleton(&self) -> bool {
4506        self.singleton
4507    }
4508
4509    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4510        if self.singleton {
4511            self.excerpts
4512                .iter()
4513                .next()
4514                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4515        } else {
4516            None
4517        }
4518    }
4519
4520    pub fn len(&self) -> MultiBufferOffset {
4521        self.diff_transforms.summary().output.len
4522    }
4523
4524    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4525        MBD::from_summary(&self.text_summary())
4526    }
4527
4528    pub fn is_empty(&self) -> bool {
4529        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4530    }
4531
4532    pub fn widest_line_number(&self) -> u32 {
4533        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4534        self.excerpts.summary().widest_line_number + 1
4535    }
4536
4537    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4538        let range = range.start.to_offset(self)..range.end.to_offset(self);
4539        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4540        excerpts.seek(&range.start);
4541
4542        let mut chunk;
4543        let mut has_trailing_newline;
4544        let excerpt_bytes;
4545        if let Some(region) = excerpts.region() {
4546            let mut bytes = region.buffer.bytes_in_range(
4547                region.buffer_range.start + (range.start - region.range.start)
4548                    ..(region.buffer_range.start + (range.end - region.range.start))
4549                        .min(region.buffer_range.end),
4550            );
4551            chunk = bytes.next().unwrap_or(&[][..]);
4552            excerpt_bytes = Some(bytes);
4553            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4554            if chunk.is_empty() && has_trailing_newline {
4555                chunk = b"\n";
4556                has_trailing_newline = false;
4557            }
4558        } else {
4559            chunk = &[][..];
4560            excerpt_bytes = None;
4561            has_trailing_newline = false;
4562        };
4563
4564        MultiBufferBytes {
4565            range,
4566            cursor: excerpts,
4567            excerpt_bytes,
4568            has_trailing_newline,
4569            chunk,
4570        }
4571    }
4572
4573    pub fn reversed_bytes_in_range<T: ToOffset>(
4574        &self,
4575        range: Range<T>,
4576    ) -> ReversedMultiBufferBytes<'_> {
4577        let range = range.start.to_offset(self)..range.end.to_offset(self);
4578        let mut chunks = self.reversed_chunks_in_range(range.clone());
4579        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4580        ReversedMultiBufferBytes {
4581            range,
4582            chunks,
4583            chunk,
4584        }
4585    }
4586
4587    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4588        let mut cursor = self.cursor::<Point, Point>();
4589        cursor.seek(&Point::new(start_row.0, 0));
4590        let mut result = MultiBufferRows {
4591            point: Point::new(0, 0),
4592            is_empty: self.excerpts.is_empty(),
4593            is_singleton: self.is_singleton(),
4594            cursor,
4595        };
4596        result.seek(start_row);
4597        result
4598    }
4599
4600    pub fn chunks<T: ToOffset>(
4601        &self,
4602        range: Range<T>,
4603        language_aware: bool,
4604    ) -> MultiBufferChunks<'_> {
4605        let mut chunks = MultiBufferChunks {
4606            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4607                ..ExcerptDimension(MultiBufferOffset::ZERO),
4608            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4609            excerpts: self.excerpts.cursor(()),
4610            diff_transforms: self.diff_transforms.cursor(()),
4611            diffs: &self.diffs,
4612            diff_base_chunks: None,
4613            excerpt_chunks: None,
4614            buffer_chunk: None,
4615            language_aware,
4616        };
4617        let range = range.start.to_offset(self)..range.end.to_offset(self);
4618        chunks.seek(range);
4619        chunks
4620    }
4621
4622    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4623        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4624    }
4625
4626    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4627        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4628    }
4629
4630    pub fn clip_offset_utf16(
4631        &self,
4632        offset: MultiBufferOffsetUtf16,
4633        bias: Bias,
4634    ) -> MultiBufferOffsetUtf16 {
4635        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4636    }
4637
4638    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4639        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4640            buffer.clip_point_utf16(Unclipped(point), bias)
4641        })
4642    }
4643
4644    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4645        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4646    }
4647
4648    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4649        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4650    }
4651
4652    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4653        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4654    }
4655
4656    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4657        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4658    }
4659
4660    #[instrument(skip_all)]
4661    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4662        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4663    }
4664
4665    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4666        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4667    }
4668
4669    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4670        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4671    }
4672
4673    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4674        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4675    }
4676
4677    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4678        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4679    }
4680
4681    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4682        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4683    }
4684
4685    fn clip_dimension<MBD, BD>(
4686        &self,
4687        position: MBD,
4688        bias: Bias,
4689        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4690    ) -> MBD
4691    where
4692        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4693        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4694    {
4695        let mut cursor = self.cursor::<MBD, BD>();
4696        cursor.seek(&position);
4697        if let Some(region) = cursor.region() {
4698            if position >= region.range.end {
4699                return region.range.end;
4700            }
4701            let overshoot = position - region.range.start;
4702            let mut buffer_position = region.buffer_range.start;
4703            buffer_position += overshoot;
4704            let clipped_buffer_position =
4705                clip_buffer_position(region.buffer, buffer_position, bias);
4706            let mut position = region.range.start;
4707            position += clipped_buffer_position - region.buffer_range.start;
4708            position
4709        } else {
4710            self.max_position()
4711        }
4712    }
4713
4714    #[instrument(skip_all)]
4715    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4716        &self,
4717        key: MBR1,
4718        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4719    ) -> MBR2
4720    where
4721        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4722        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4723        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4724        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4725    {
4726        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4727        cursor.seek(&DimensionPair { key, value: None });
4728        if let Some(region) = cursor.region() {
4729            if key >= region.range.end.key {
4730                return region.range.end.value.unwrap();
4731            }
4732            let start_key = region.range.start.key;
4733            let start_value = region.range.start.value.unwrap();
4734            let buffer_start_key = region.buffer_range.start.key;
4735            let buffer_start_value = region.buffer_range.start.value.unwrap();
4736            let mut buffer_key = buffer_start_key;
4737            buffer_key += key - start_key;
4738            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4739            let mut result = start_value;
4740            result += buffer_value - buffer_start_value;
4741            result
4742        } else {
4743            self.max_position()
4744        }
4745    }
4746
4747    pub fn point_to_buffer_offset<T: ToOffset>(
4748        &self,
4749        point: T,
4750    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4751        let offset = point.to_offset(self);
4752        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4753        cursor.seek(&offset);
4754        let region = cursor.region()?;
4755        let overshoot = offset - region.range.start;
4756        let buffer_offset = region.buffer_range.start + overshoot;
4757        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4758            && region.has_trailing_newline
4759            && !region.is_main_buffer
4760        {
4761            let main_buffer_position = cursor.main_buffer_position()?;
4762            let buffer_snapshot = &cursor.excerpt()?.buffer;
4763            return Some((buffer_snapshot, main_buffer_position));
4764        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4765            return None;
4766        }
4767        Some((region.buffer, buffer_offset))
4768    }
4769
4770    pub fn point_to_buffer_point(
4771        &self,
4772        point: Point,
4773    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4774        let mut cursor = self.cursor::<Point, Point>();
4775        cursor.seek(&point);
4776        let region = cursor.region()?;
4777        let overshoot = point - region.range.start;
4778        let buffer_point = region.buffer_range.start + overshoot;
4779        let excerpt = cursor.excerpt()?;
4780        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4781            && region.has_trailing_newline
4782            && !region.is_main_buffer
4783        {
4784            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4785        } else if buffer_point > region.buffer.max_point() {
4786            return None;
4787        }
4788        Some((region.buffer, buffer_point, excerpt.id))
4789    }
4790
4791    pub fn suggested_indents(
4792        &self,
4793        rows: impl IntoIterator<Item = u32>,
4794        cx: &App,
4795    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4796        let mut result = BTreeMap::new();
4797        self.suggested_indents_callback(
4798            rows,
4799            |row, indent| {
4800                result.insert(row, indent);
4801                ControlFlow::Continue(())
4802            },
4803            cx,
4804        );
4805        result
4806    }
4807
4808    // move this to be a generator once those are a thing
4809    pub fn suggested_indents_callback(
4810        &self,
4811        rows: impl IntoIterator<Item = u32>,
4812        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4813        cx: &App,
4814    ) {
4815        let mut rows_for_excerpt = Vec::new();
4816        let mut cursor = self.cursor::<Point, Point>();
4817        let mut rows = rows.into_iter().peekable();
4818        let mut prev_row = u32::MAX;
4819        let mut prev_language_indent_size = IndentSize::default();
4820
4821        while let Some(row) = rows.next() {
4822            cursor.seek(&Point::new(row, 0));
4823            let Some(region) = cursor.region() else {
4824                continue;
4825            };
4826
4827            // Retrieve the language and indent size once for each disjoint region being indented.
4828            let single_indent_size = if row.saturating_sub(1) == prev_row {
4829                prev_language_indent_size
4830            } else {
4831                region
4832                    .buffer
4833                    .language_indent_size_at(Point::new(row, 0), cx)
4834            };
4835            prev_language_indent_size = single_indent_size;
4836            prev_row = row;
4837
4838            let start_buffer_row = region.buffer_range.start.row;
4839            let start_multibuffer_row = region.range.start.row;
4840            let end_multibuffer_row = region.range.end.row;
4841
4842            rows_for_excerpt.push(row);
4843            while let Some(next_row) = rows.peek().copied() {
4844                if end_multibuffer_row > next_row {
4845                    rows_for_excerpt.push(next_row);
4846                    rows.next();
4847                } else {
4848                    break;
4849                }
4850            }
4851
4852            let buffer_rows = rows_for_excerpt
4853                .drain(..)
4854                .map(|row| start_buffer_row + row - start_multibuffer_row);
4855            let buffer_indents = region
4856                .buffer
4857                .suggested_indents(buffer_rows, single_indent_size);
4858            for (row, indent) in buffer_indents {
4859                if cb(
4860                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4861                    indent,
4862                )
4863                .is_break()
4864                {
4865                    return;
4866                }
4867            }
4868        }
4869    }
4870
4871    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4872        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4873            let mut size = buffer.indent_size_for_line(range.start.row);
4874            size.len = size
4875                .len
4876                .min(range.end.column)
4877                .saturating_sub(range.start.column);
4878            size
4879        } else {
4880            IndentSize::spaces(0)
4881        }
4882    }
4883
4884    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4885        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4886            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4887        } else {
4888            LineIndent::spaces(0)
4889        }
4890    }
4891
4892    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4893        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4894
4895        if self.language_settings(cx).extend_comment_on_newline
4896            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4897        {
4898            let delimiters = language_scope.line_comment_prefixes();
4899            for delimiter in delimiters {
4900                if *self
4901                    .chars_at(Point::new(row.0, indent.len() as u32))
4902                    .take(delimiter.chars().count())
4903                    .collect::<String>()
4904                    .as_str()
4905                    == **delimiter
4906                {
4907                    indent.push_str(delimiter);
4908                    break;
4909                }
4910            }
4911        }
4912
4913        indent
4914    }
4915
4916    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4917    where
4918        T: ToOffset,
4919    {
4920        for char in self.reversed_chars_at(position) {
4921            if !char.is_whitespace() {
4922                return false;
4923            }
4924            if char == '\n' {
4925                return true;
4926            }
4927        }
4928        true
4929    }
4930
4931    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4932        while row.0 > 0 {
4933            row.0 -= 1;
4934            if !self.is_line_blank(row) {
4935                return Some(row);
4936            }
4937        }
4938        None
4939    }
4940
4941    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4942        if let Some((_, range)) = self.buffer_line_for_row(row) {
4943            range.end.column - range.start.column
4944        } else {
4945            0
4946        }
4947    }
4948
4949    pub fn buffer_line_for_row(
4950        &self,
4951        row: MultiBufferRow,
4952    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4953        let mut cursor = self.cursor::<Point, Point>();
4954        let point = Point::new(row.0, 0);
4955        cursor.seek(&point);
4956        let region = cursor.region()?;
4957        let overshoot = point.min(region.range.end) - region.range.start;
4958        let buffer_point = region.buffer_range.start + overshoot;
4959        if buffer_point.row > region.buffer_range.end.row {
4960            return None;
4961        }
4962        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4963        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4964            .min(region.buffer_range.end);
4965        Some((region.buffer, line_start..line_end))
4966    }
4967
4968    pub fn max_point(&self) -> Point {
4969        self.text_summary().lines
4970    }
4971
4972    pub fn max_row(&self) -> MultiBufferRow {
4973        MultiBufferRow(self.text_summary().lines.row)
4974    }
4975
4976    pub fn text_summary(&self) -> MBTextSummary {
4977        self.diff_transforms.summary().output
4978    }
4979
4980    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4981    where
4982        MBD: MultiBufferDimension + AddAssign,
4983        O: ToOffset,
4984    {
4985        let range = range.start.to_offset(self)..range.end.to_offset(self);
4986        let mut cursor = self
4987            .diff_transforms
4988            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4989        cursor.seek(&range.start, Bias::Right);
4990
4991        let Some(first_transform) = cursor.item() else {
4992            return MBD::from_summary(&MBTextSummary::default());
4993        };
4994
4995        let diff_transform_start = cursor.start().0;
4996        let diff_transform_end = cursor.end().0;
4997        let diff_start = range.start;
4998        let start_overshoot = diff_start - diff_transform_start;
4999        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5000
5001        let mut result = match first_transform {
5002            DiffTransform::BufferContent { .. } => {
5003                let excerpt_start = cursor.start().1 + start_overshoot;
5004                let excerpt_end = cursor.start().1 + end_overshoot;
5005                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5006            }
5007            DiffTransform::DeletedHunk {
5008                buffer_id,
5009                base_text_byte_range,
5010                has_trailing_newline,
5011                ..
5012            } => {
5013                let buffer_start = base_text_byte_range.start + start_overshoot;
5014                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5015                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5016                    panic!("{:?} is in non-existent deleted hunk", range.start)
5017                };
5018
5019                let include_trailing_newline =
5020                    *has_trailing_newline && range.end >= diff_transform_end;
5021                if include_trailing_newline {
5022                    buffer_end -= 1;
5023                }
5024
5025                let mut summary = base_text
5026                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5027
5028                if include_trailing_newline {
5029                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5030                        &TextSummary::newline(),
5031                    ))
5032                }
5033
5034                let mut result = MBD::default();
5035                result.add_text_dim(&summary);
5036                result
5037            }
5038        };
5039        if range.end < diff_transform_end {
5040            return result;
5041        }
5042
5043        cursor.next();
5044        result.add_mb_text_summary(
5045            &cursor
5046                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5047                .0,
5048        );
5049
5050        let Some(last_transform) = cursor.item() else {
5051            return result;
5052        };
5053
5054        let overshoot = range.end - cursor.start().0;
5055        let suffix = match last_transform {
5056            DiffTransform::BufferContent { .. } => {
5057                let end = cursor.start().1 + overshoot;
5058                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5059            }
5060            DiffTransform::DeletedHunk {
5061                base_text_byte_range,
5062                buffer_id,
5063                has_trailing_newline,
5064                ..
5065            } => {
5066                let buffer_end = base_text_byte_range.start + overshoot;
5067                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5068                    panic!("{:?} is in non-existent deleted hunk", range.end)
5069                };
5070
5071                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5072                    base_text_byte_range.start..buffer_end,
5073                );
5074                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5075                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5076                        &TextSummary::from("\n"),
5077                    ))
5078                }
5079
5080                let mut result = MBD::default();
5081                result.add_text_dim(&suffix);
5082                result
5083            }
5084        };
5085
5086        result += suffix;
5087        result
5088    }
5089
5090    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5091    where
5092        MBD: MultiBufferDimension + AddAssign,
5093    {
5094        let mut summary = MBD::default();
5095        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5096        cursor.seek(&range.start, Bias::Right);
5097        if let Some(excerpt) = cursor.item() {
5098            let mut end_before_newline = cursor.end();
5099            if excerpt.has_trailing_newline {
5100                end_before_newline -= 1;
5101            }
5102
5103            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5104            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5105            let end_in_excerpt =
5106                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5107            summary.add_text_dim(
5108                &excerpt
5109                    .buffer
5110                    .text_summary_for_range::<MBD::TextDimension, _>(
5111                        start_in_excerpt..end_in_excerpt,
5112                    ),
5113            );
5114
5115            if range.end > end_before_newline {
5116                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5117            }
5118
5119            cursor.next();
5120        }
5121
5122        if range.end > *cursor.start() {
5123            summary += cursor
5124                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5125                .0;
5126            if let Some(excerpt) = cursor.item() {
5127                range.end = cmp::max(*cursor.start(), range.end);
5128
5129                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5130                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5131                summary.add_text_dim(
5132                    &excerpt
5133                        .buffer
5134                        .text_summary_for_range::<MBD::TextDimension, _>(
5135                            excerpt_start..end_in_excerpt,
5136                        ),
5137                );
5138            }
5139        }
5140
5141        summary
5142    }
5143
5144    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5145    where
5146        MBD: MultiBufferDimension
5147            + Ord
5148            + Sub<Output = MBD::TextDimension>
5149            + Sub<MBD::TextDimension, Output = MBD>
5150            + AddAssign<MBD::TextDimension>
5151            + Add<MBD::TextDimension, Output = MBD>,
5152        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5153    {
5154        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5155        let locator = self.excerpt_locator_for_id(excerpt_id);
5156        let (start, _, mut item) = self
5157            .excerpts
5158            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5159        let mut start = MBD::from_summary(&start.text);
5160        if item.is_none() && excerpt_id == ExcerptId::max() {
5161            item = self.excerpts.last();
5162            if let Some(last_summary) = self.excerpts.last_summary() {
5163                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5164            }
5165        }
5166
5167        if self.diff_transforms.is_empty() {
5168            let excerpt_start_position = ExcerptDimension(start);
5169            if let Some(excerpt) = item {
5170                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5171                    return excerpt_start_position.0;
5172                }
5173                let excerpt_buffer_start = excerpt
5174                    .range
5175                    .context
5176                    .start
5177                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5178                let excerpt_buffer_end = excerpt
5179                    .range
5180                    .context
5181                    .end
5182                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5183                let buffer_summary = anchor
5184                    .text_anchor
5185                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5186                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5187                let mut position = excerpt_start_position;
5188                if summary > excerpt_buffer_start {
5189                    position += summary - excerpt_buffer_start;
5190                }
5191
5192                position.0
5193            } else {
5194                excerpt_start_position.0
5195            }
5196        } else {
5197            let mut diff_transforms_cursor = self
5198                .diff_transforms
5199                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5200            diff_transforms_cursor.next();
5201
5202            let excerpt_start_position = ExcerptDimension(start);
5203            if let Some(excerpt) = item {
5204                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5205                    return self.resolve_summary_for_anchor(
5206                        &Anchor::min(),
5207                        excerpt_start_position,
5208                        &mut diff_transforms_cursor,
5209                    );
5210                }
5211                let excerpt_buffer_start = excerpt
5212                    .range
5213                    .context
5214                    .start
5215                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5216                let excerpt_buffer_end = excerpt
5217                    .range
5218                    .context
5219                    .end
5220                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5221                let buffer_summary = anchor
5222                    .text_anchor
5223                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5224                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5225                let mut position = excerpt_start_position;
5226                if summary > excerpt_buffer_start {
5227                    position += summary - excerpt_buffer_start;
5228                }
5229
5230                if diff_transforms_cursor.start().0 < position {
5231                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5232                }
5233                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5234            } else {
5235                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5236                self.resolve_summary_for_anchor(
5237                    &Anchor::max(),
5238                    excerpt_start_position,
5239                    &mut diff_transforms_cursor,
5240                )
5241            }
5242        }
5243    }
5244
5245    fn resolve_summary_for_anchor<MBD>(
5246        &self,
5247        anchor: &Anchor,
5248        excerpt_position: ExcerptDimension<MBD>,
5249        diff_transforms: &mut Cursor<
5250            DiffTransform,
5251            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5252        >,
5253    ) -> MBD
5254    where
5255        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5256    {
5257        loop {
5258            let transform_end_position = diff_transforms.end().0;
5259            let at_transform_end =
5260                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5261            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5262                diff_transforms.next();
5263                continue;
5264            }
5265
5266            let mut position = diff_transforms.start().1;
5267            match diff_transforms.item() {
5268                Some(DiffTransform::DeletedHunk {
5269                    buffer_id,
5270                    base_text_byte_range,
5271                    ..
5272                }) => {
5273                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5274                        && let Some(base_text) =
5275                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5276                        && diff_base_anchor.is_valid(&base_text)
5277                    {
5278                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5279                        if base_text_offset >= base_text_byte_range.start
5280                            && base_text_offset <= base_text_byte_range.end
5281                        {
5282                            let position_in_hunk = base_text
5283                                .text_summary_for_range::<MBD::TextDimension, _>(
5284                                    base_text_byte_range.start..base_text_offset,
5285                                );
5286                            position.0.add_text_dim(&position_in_hunk);
5287                        } else if at_transform_end {
5288                            diff_transforms.next();
5289                            continue;
5290                        }
5291                    }
5292                }
5293                _ => {
5294                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5295                        diff_transforms.next();
5296                        continue;
5297                    }
5298                    let overshoot = excerpt_position - diff_transforms.start().0;
5299                    position += overshoot;
5300                }
5301            }
5302
5303            return position.0;
5304        }
5305    }
5306
5307    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5308        let mut cursor = self
5309            .excerpts
5310            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5311        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5312
5313        cursor.seek(&Some(locator), Bias::Left);
5314        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5315            cursor.prev();
5316        }
5317
5318        let mut position = cursor.start().1;
5319        if let Some(excerpt) = cursor.item()
5320            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5321        {
5322            let excerpt_buffer_start = excerpt
5323                .buffer
5324                .offset_for_anchor(&excerpt.range.context.start);
5325            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5326            let buffer_position = cmp::min(
5327                excerpt_buffer_end,
5328                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5329            );
5330            if buffer_position > excerpt_buffer_start {
5331                position += buffer_position - excerpt_buffer_start;
5332            }
5333        }
5334        position
5335    }
5336
5337    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5338        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5339            excerpt_id = *replacement;
5340        }
5341        excerpt_id
5342    }
5343
5344    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5345    where
5346        MBD: MultiBufferDimension
5347            + Ord
5348            + Sub<Output = MBD::TextDimension>
5349            + AddAssign<MBD::TextDimension>,
5350        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5351        I: 'a + IntoIterator<Item = &'a Anchor>,
5352    {
5353        let mut anchors = anchors.into_iter().peekable();
5354        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5355        let mut diff_transforms_cursor = self
5356            .diff_transforms
5357            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5358        diff_transforms_cursor.next();
5359
5360        let mut summaries = Vec::new();
5361        while let Some(anchor) = anchors.peek() {
5362            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5363
5364            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5365                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5366            });
5367
5368            let locator = self.excerpt_locator_for_id(excerpt_id);
5369            cursor.seek_forward(locator, Bias::Left);
5370            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5371                cursor.prev();
5372            }
5373
5374            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5375            if let Some(excerpt) = cursor.item() {
5376                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5377                    let position = self.resolve_summary_for_anchor(
5378                        &Anchor::min(),
5379                        excerpt_start_position,
5380                        &mut diff_transforms_cursor,
5381                    );
5382                    summaries.extend(excerpt_anchors.map(|_| position));
5383                    continue;
5384                }
5385                let excerpt_buffer_start = excerpt
5386                    .range
5387                    .context
5388                    .start
5389                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5390                let excerpt_buffer_end = excerpt
5391                    .range
5392                    .context
5393                    .end
5394                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5395                for (buffer_summary, anchor) in excerpt
5396                    .buffer
5397                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5398                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5399                    )
5400                {
5401                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5402                    let mut position = excerpt_start_position;
5403                    if summary > excerpt_buffer_start {
5404                        position += summary - excerpt_buffer_start;
5405                    }
5406
5407                    if diff_transforms_cursor.start().0 < position {
5408                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5409                    }
5410
5411                    summaries.push(self.resolve_summary_for_anchor(
5412                        anchor,
5413                        position,
5414                        &mut diff_transforms_cursor,
5415                    ));
5416                }
5417            } else {
5418                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5419                let position = self.resolve_summary_for_anchor(
5420                    &Anchor::max(),
5421                    excerpt_start_position,
5422                    &mut diff_transforms_cursor,
5423                );
5424                summaries.extend(excerpt_anchors.map(|_| position));
5425            }
5426        }
5427
5428        summaries
5429    }
5430
5431    pub fn dimensions_from_points<'a, MBD>(
5432        &'a self,
5433        points: impl 'a + IntoIterator<Item = Point>,
5434    ) -> impl 'a + Iterator<Item = MBD>
5435    where
5436        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5437    {
5438        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5439        cursor.seek(&DimensionPair {
5440            key: Point::default(),
5441            value: None,
5442        });
5443        let mut points = points.into_iter();
5444        iter::from_fn(move || {
5445            let point = points.next()?;
5446
5447            cursor.seek_forward(&DimensionPair {
5448                key: point,
5449                value: None,
5450            });
5451
5452            if let Some(region) = cursor.region() {
5453                let overshoot = point - region.range.start.key;
5454                let buffer_point = region.buffer_range.start + overshoot;
5455                let mut position = region.range.start.value.unwrap();
5456                position.add_text_dim(
5457                    &region
5458                        .buffer
5459                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5460                );
5461                if point == region.range.end.key && region.has_trailing_newline {
5462                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5463                }
5464                Some(position)
5465            } else {
5466                Some(MBD::from_summary(&self.text_summary()))
5467            }
5468        })
5469    }
5470
5471    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5472    where
5473        I: 'a + IntoIterator<Item = &'a Anchor>,
5474    {
5475        let mut anchors = anchors.into_iter().enumerate().peekable();
5476        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5477        cursor.next();
5478
5479        let mut result = Vec::new();
5480
5481        while let Some((_, anchor)) = anchors.peek() {
5482            let old_excerpt_id = anchor.excerpt_id;
5483
5484            // Find the location where this anchor's excerpt should be.
5485            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5486            cursor.seek_forward(&Some(old_locator), Bias::Left);
5487
5488            let next_excerpt = cursor.item();
5489            let prev_excerpt = cursor.prev_item();
5490
5491            // Process all of the anchors for this excerpt.
5492            while let Some((anchor_ix, &anchor)) =
5493                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5494            {
5495                let mut anchor = anchor;
5496
5497                // Leave min and max anchors unchanged if invalid or
5498                // if the old excerpt still exists at this location
5499                let mut kept_position = next_excerpt
5500                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5501                    || old_excerpt_id == ExcerptId::max()
5502                    || old_excerpt_id == ExcerptId::min();
5503
5504                // If the old excerpt no longer exists at this location, then attempt to
5505                // find an equivalent position for this anchor in an adjacent excerpt.
5506                if !kept_position {
5507                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5508                        if excerpt.contains(&anchor) {
5509                            anchor.excerpt_id = excerpt.id;
5510                            kept_position = true;
5511                            break;
5512                        }
5513                    }
5514                }
5515
5516                // If there's no adjacent excerpt that contains the anchor's position,
5517                // then report that the anchor has lost its position.
5518                if !kept_position {
5519                    anchor = if let Some(excerpt) = next_excerpt {
5520                        let mut text_anchor = excerpt
5521                            .range
5522                            .context
5523                            .start
5524                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5525                        if text_anchor
5526                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5527                            .is_gt()
5528                        {
5529                            text_anchor = excerpt.range.context.end;
5530                        }
5531                        Anchor::in_buffer(excerpt.id, text_anchor)
5532                    } else if let Some(excerpt) = prev_excerpt {
5533                        let mut text_anchor = excerpt
5534                            .range
5535                            .context
5536                            .end
5537                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5538                        if text_anchor
5539                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5540                            .is_lt()
5541                        {
5542                            text_anchor = excerpt.range.context.start;
5543                        }
5544                        Anchor::in_buffer(excerpt.id, text_anchor)
5545                    } else if anchor.text_anchor.bias == Bias::Left {
5546                        Anchor::min()
5547                    } else {
5548                        Anchor::max()
5549                    };
5550                }
5551
5552                result.push((anchor_ix, anchor, kept_position));
5553            }
5554        }
5555        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5556        result
5557    }
5558
5559    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5560        self.anchor_at(position, Bias::Left)
5561    }
5562
5563    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5564        self.anchor_at(position, Bias::Right)
5565    }
5566
5567    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5568        let offset = position.to_offset(self);
5569
5570        // Find the given position in the diff transforms. Determine the corresponding
5571        // offset in the excerpts, and whether the position is within a deleted hunk.
5572        let mut diff_transforms = self
5573            .diff_transforms
5574            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5575        diff_transforms.seek(&offset, Bias::Right);
5576
5577        if offset == diff_transforms.start().0
5578            && bias == Bias::Left
5579            && let Some(prev_item) = diff_transforms.prev_item()
5580            && let DiffTransform::DeletedHunk { .. } = prev_item
5581        {
5582            diff_transforms.prev();
5583        }
5584        let offset_in_transform = offset - diff_transforms.start().0;
5585        let mut excerpt_offset = diff_transforms.start().1;
5586        let mut diff_base_anchor = None;
5587        if let Some(DiffTransform::DeletedHunk {
5588            buffer_id,
5589            base_text_byte_range,
5590            has_trailing_newline,
5591            ..
5592        }) = diff_transforms.item()
5593        {
5594            let diff = self.diffs.get(buffer_id).expect("missing diff");
5595            if offset_in_transform > base_text_byte_range.len() {
5596                debug_assert!(*has_trailing_newline);
5597                bias = Bias::Right;
5598            } else {
5599                diff_base_anchor = Some(
5600                    diff.base_text()
5601                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5602                );
5603                bias = Bias::Left;
5604            }
5605        } else {
5606            excerpt_offset += MultiBufferOffset(offset_in_transform);
5607        };
5608
5609        let mut excerpts = self
5610            .excerpts
5611            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5612        excerpts.seek(&excerpt_offset, Bias::Right);
5613        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5614            excerpts.prev();
5615        }
5616        if let Some(excerpt) = excerpts.item() {
5617            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5618            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5619                overshoot -= 1;
5620                bias = Bias::Right;
5621            }
5622
5623            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5624            let text_anchor =
5625                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5626            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5627            match diff_base_anchor {
5628                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5629                None => anchor,
5630            }
5631        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5632        {
5633            Anchor::min()
5634        } else {
5635            Anchor::max()
5636        }
5637    }
5638
5639    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5640    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5641        let (excerpt, buffer, _) = self.as_singleton()?;
5642        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5643            Some(Anchor::in_buffer(*excerpt, text_anchor))
5644        } else {
5645            None
5646        }
5647    }
5648
5649    /// Returns an anchor for the given excerpt and text anchor,
5650    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5651    pub fn anchor_range_in_excerpt(
5652        &self,
5653        excerpt_id: ExcerptId,
5654        text_anchor: Range<text::Anchor>,
5655    ) -> Option<Range<Anchor>> {
5656        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5657
5658        Some(
5659            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5660                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5661        )
5662    }
5663
5664    /// Returns an anchor for the given excerpt and text anchor,
5665    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5666    pub fn anchor_in_excerpt(
5667        &self,
5668        excerpt_id: ExcerptId,
5669        text_anchor: text::Anchor,
5670    ) -> Option<Anchor> {
5671        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5672        Self::anchor_in_excerpt_(excerpt, text_anchor)
5673    }
5674
5675    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5676    pub fn anchors_in_excerpt(
5677        &self,
5678        excerpt_id: ExcerptId,
5679        text_anchors: impl IntoIterator<Item = text::Anchor>,
5680    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5681        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5682        Some(
5683            text_anchors
5684                .into_iter()
5685                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5686        )
5687    }
5688
5689    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5690        match text_anchor.buffer_id {
5691            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5692            Some(_) => return None,
5693            None if text_anchor.is_max() || text_anchor.is_min() => {
5694                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5695            }
5696            None => return None,
5697        }
5698
5699        let context = &excerpt.range.context;
5700        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5701            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5702        {
5703            return None;
5704        }
5705
5706        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5707    }
5708
5709    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5710        Some(self.excerpt(excerpt_id)?.range.context.clone())
5711    }
5712
5713    pub fn excerpt_range_for_excerpt(
5714        &self,
5715        excerpt_id: ExcerptId,
5716    ) -> Option<ExcerptRange<text::Anchor>> {
5717        Some(self.excerpt(excerpt_id)?.range.clone())
5718    }
5719
5720    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5721        if anchor.is_min() || anchor.is_max() {
5722            // todo(lw): should be `!self.is_empty()`
5723            true
5724        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5725            excerpt.buffer.can_resolve(&anchor.text_anchor)
5726        } else {
5727            false
5728        }
5729    }
5730
5731    pub fn excerpts(
5732        &self,
5733    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5734        self.excerpts
5735            .iter()
5736            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5737    }
5738
5739    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5740    where
5741        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5742        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5743    {
5744        let excerpts = self.excerpts.cursor(());
5745        let diff_transforms = self.diff_transforms.cursor(());
5746        MultiBufferCursor {
5747            excerpts,
5748            diff_transforms,
5749            diffs: &self.diffs,
5750            cached_region: OnceCell::new(),
5751        }
5752    }
5753
5754    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5755        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5756        let mut excerpts = self
5757            .excerpts
5758            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5759        excerpts.seek(&Some(start_locator), Bias::Left);
5760        excerpts.prev();
5761
5762        let mut diff_transforms = self
5763            .diff_transforms
5764            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5765        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5766        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5767            diff_transforms.next();
5768        }
5769
5770        let excerpt = excerpts.item()?;
5771        Some(MultiBufferExcerpt {
5772            excerpt,
5773            offset: diff_transforms.start().output_dimension.0,
5774            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5775            excerpt_offset: excerpts.start().1,
5776            diff_transforms,
5777        })
5778    }
5779
5780    pub fn excerpt_boundaries_in_range<R, T>(
5781        &self,
5782        range: R,
5783    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5784    where
5785        R: RangeBounds<T>,
5786        T: ToOffset,
5787    {
5788        let start_offset;
5789        let start = match range.start_bound() {
5790            Bound::Included(start) => {
5791                start_offset = start.to_offset(self);
5792                Bound::Included(start_offset)
5793            }
5794            Bound::Excluded(_) => {
5795                panic!("not supported")
5796            }
5797            Bound::Unbounded => {
5798                start_offset = MultiBufferOffset::ZERO;
5799                Bound::Unbounded
5800            }
5801        };
5802        let end = match range.end_bound() {
5803            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5804            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5805            Bound::Unbounded => Bound::Unbounded,
5806        };
5807        let bounds = (start, end);
5808        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5809        cursor.seek(&DimensionPair {
5810            key: start_offset,
5811            value: None,
5812        });
5813
5814        if cursor
5815            .fetch_excerpt_with_range()
5816            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5817        {
5818            cursor.prev_excerpt();
5819        } else {
5820            cursor.seek_to_start_of_current_excerpt();
5821        }
5822        let mut prev_region = cursor
5823            .fetch_excerpt_with_range()
5824            .map(|(excerpt, _)| excerpt);
5825
5826        cursor.next_excerpt_forwards();
5827
5828        iter::from_fn(move || {
5829            loop {
5830                if self.singleton {
5831                    return None;
5832                }
5833
5834                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5835                cursor.next_excerpt_forwards();
5836                if !bounds.contains(&next_range.start.key) {
5837                    prev_region = Some(next_excerpt);
5838                    continue;
5839                }
5840
5841                let next_region_start = next_range.start.value.unwrap();
5842                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5843                    range.start.value.unwrap()
5844                } else {
5845                    self.max_point()
5846                };
5847
5848                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5849                    id: region.id,
5850                    buffer: region.buffer.clone(),
5851                    buffer_id: region.buffer_id,
5852                    range: region.range.clone(),
5853                    end_row: MultiBufferRow(next_region_start.row),
5854                });
5855
5856                let next = ExcerptInfo {
5857                    id: next_excerpt.id,
5858                    buffer: next_excerpt.buffer.clone(),
5859                    buffer_id: next_excerpt.buffer_id,
5860                    range: next_excerpt.range.clone(),
5861                    end_row: if next_excerpt.has_trailing_newline {
5862                        MultiBufferRow(next_region_end.row - 1)
5863                    } else {
5864                        MultiBufferRow(next_region_end.row)
5865                    },
5866                };
5867
5868                let row = MultiBufferRow(next_region_start.row);
5869
5870                prev_region = Some(next_excerpt);
5871
5872                return Some(ExcerptBoundary { row, prev, next });
5873            }
5874        })
5875    }
5876
5877    pub fn edit_count(&self) -> usize {
5878        self.edit_count
5879    }
5880
5881    pub fn non_text_state_update_count(&self) -> usize {
5882        self.non_text_state_update_count
5883    }
5884
5885    /// Returns the smallest enclosing bracket ranges containing the given range or
5886    /// None if no brackets contain range or the range is not contained in a single
5887    /// excerpt
5888    ///
5889    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5890    #[ztracing::instrument(skip_all)]
5891    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5892        &self,
5893        range: Range<T>,
5894        range_filter: Option<
5895            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5896        >,
5897    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5898        let range = range.start.to_offset(self)..range.end.to_offset(self);
5899        let mut excerpt = self.excerpt_containing(range.clone())?;
5900        let buffer = excerpt.buffer();
5901        let excerpt_buffer_range = excerpt.buffer_range();
5902
5903        // Filter to ranges contained in the excerpt
5904        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5905            excerpt_buffer_range.contains(&BufferOffset(open.start))
5906                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5907                && range_filter.is_none_or(|filter| {
5908                    filter(
5909                        buffer,
5910                        BufferOffset(open.start)..BufferOffset(close.end),
5911                        BufferOffset(close.start)..BufferOffset(close.end),
5912                    )
5913                })
5914        };
5915
5916        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5917            excerpt.map_range_to_buffer(range),
5918            Some(&range_filter),
5919        )?;
5920
5921        Some((
5922            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5923            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5924        ))
5925    }
5926
5927    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5928    /// not contained in a single excerpt
5929    pub fn enclosing_bracket_ranges<T: ToOffset>(
5930        &self,
5931        range: Range<T>,
5932    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5933    {
5934        let range = range.start.to_offset(self)..range.end.to_offset(self);
5935        let mut excerpt = self.excerpt_containing(range.clone())?;
5936
5937        Some(
5938            excerpt
5939                .buffer()
5940                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5941                .filter_map(move |pair| {
5942                    let open_range =
5943                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5944                    let close_range =
5945                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5946                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5947                        Some((
5948                            excerpt.map_range_from_buffer(open_range),
5949                            excerpt.map_range_from_buffer(close_range),
5950                        ))
5951                    } else {
5952                        None
5953                    }
5954                }),
5955        )
5956    }
5957
5958    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5959    /// not contained in a single excerpt
5960    pub fn text_object_ranges<T: ToOffset>(
5961        &self,
5962        range: Range<T>,
5963        options: TreeSitterOptions,
5964    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5965        let range = range.start.to_offset(self)..range.end.to_offset(self);
5966        self.excerpt_containing(range.clone())
5967            .map(|mut excerpt| {
5968                excerpt
5969                    .buffer()
5970                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5971                    .filter_map(move |(range, text_object)| {
5972                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5973                        if excerpt.contains_buffer_range(range.clone()) {
5974                            Some((excerpt.map_range_from_buffer(range), text_object))
5975                        } else {
5976                            None
5977                        }
5978                    })
5979            })
5980            .into_iter()
5981            .flatten()
5982    }
5983
5984    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5985    /// not contained in a single excerpt
5986    pub fn bracket_ranges<T: ToOffset>(
5987        &self,
5988        range: Range<T>,
5989    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5990    {
5991        let range = range.start.to_offset(self)..range.end.to_offset(self);
5992        let mut excerpt = self.excerpt_containing(range.clone())?;
5993        Some(
5994            excerpt
5995                .buffer()
5996                .bracket_ranges(excerpt.map_range_to_buffer(range))
5997                .filter_map(move |pair| {
5998                    let open_range =
5999                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6000                    let close_range =
6001                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6002                    excerpt
6003                        .contains_buffer_range(open_range.start..close_range.end)
6004                        .then(|| BracketMatch {
6005                            open_range: excerpt.map_range_from_buffer(open_range),
6006                            close_range: excerpt.map_range_from_buffer(close_range),
6007                            color_index: pair.color_index,
6008                            newline_only: pair.newline_only,
6009                            syntax_layer_depth: pair.syntax_layer_depth,
6010                        })
6011                })
6012                .map(BracketMatch::bracket_ranges),
6013        )
6014    }
6015
6016    pub fn redacted_ranges<'a, T: ToOffset>(
6017        &'a self,
6018        range: Range<T>,
6019        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6020    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6021        let range = range.start.to_offset(self)..range.end.to_offset(self);
6022        self.lift_buffer_metadata(range, move |buffer, range| {
6023            if redaction_enabled(buffer.file()) {
6024                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6025            } else {
6026                None
6027            }
6028        })
6029        .map(|(range, _, _)| range)
6030    }
6031
6032    pub fn runnable_ranges(
6033        &self,
6034        range: Range<Anchor>,
6035    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6036        let range = range.start.to_offset(self)..range.end.to_offset(self);
6037        self.lift_buffer_metadata(range, move |buffer, range| {
6038            Some(
6039                buffer
6040                    .runnable_ranges(range.clone())
6041                    .filter(move |runnable| {
6042                        runnable.run_range.start >= range.start
6043                            && runnable.run_range.end < range.end
6044                    })
6045                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6046            )
6047        })
6048        .map(|(run_range, runnable, _)| (run_range, runnable))
6049    }
6050
6051    pub fn line_indents(
6052        &self,
6053        start_row: MultiBufferRow,
6054        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6055    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6056        let max_point = self.max_point();
6057        let mut cursor = self.cursor::<Point, Point>();
6058        cursor.seek(&Point::new(start_row.0, 0));
6059        iter::from_fn(move || {
6060            let mut region = cursor.region()?;
6061            while !buffer_filter(&region.excerpt.buffer) {
6062                cursor.next();
6063                region = cursor.region()?;
6064            }
6065            let region = cursor.region()?;
6066            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6067            let buffer_start_row =
6068                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6069
6070            let buffer_end_row = if region.is_main_buffer
6071                && (region.has_trailing_newline || region.range.end == max_point)
6072            {
6073                region.buffer_range.end.row
6074            } else {
6075                region.buffer_range.end.row.saturating_sub(1)
6076            };
6077
6078            let line_indents = region
6079                .buffer
6080                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6081            let region_buffer_row = region.buffer_range.start.row;
6082            let region_row = region.range.start.row;
6083            let region_buffer = &region.excerpt.buffer;
6084            cursor.next();
6085            Some(line_indents.map(move |(buffer_row, indent)| {
6086                let row = region_row + (buffer_row - region_buffer_row);
6087                (MultiBufferRow(row), indent, region_buffer.as_ref())
6088            }))
6089        })
6090        .flatten()
6091    }
6092
6093    pub fn reversed_line_indents(
6094        &self,
6095        end_row: MultiBufferRow,
6096        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6097    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6098        let max_point = self.max_point();
6099        let mut cursor = self.cursor::<Point, Point>();
6100        cursor.seek(&Point::new(end_row.0, 0));
6101        iter::from_fn(move || {
6102            let mut region = cursor.region()?;
6103            while !buffer_filter(&region.excerpt.buffer) {
6104                cursor.prev();
6105                region = cursor.region()?;
6106            }
6107            let region = cursor.region()?;
6108
6109            let buffer_start_row = region.buffer_range.start.row;
6110            let buffer_end_row = if region.is_main_buffer
6111                && (region.has_trailing_newline || region.range.end == max_point)
6112            {
6113                region.buffer_range.end.row + 1
6114            } else {
6115                region.buffer_range.end.row
6116            };
6117
6118            let overshoot = end_row.0 - region.range.start.row;
6119            let buffer_end_row =
6120                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6121
6122            let line_indents = region
6123                .buffer
6124                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6125            let region_buffer_row = region.buffer_range.start.row;
6126            let region_row = region.range.start.row;
6127            let region_buffer = &region.excerpt.buffer;
6128            cursor.prev();
6129            Some(line_indents.map(move |(buffer_row, indent)| {
6130                let row = region_row + (buffer_row - region_buffer_row);
6131                (MultiBufferRow(row), indent, region_buffer.as_ref())
6132            }))
6133        })
6134        .flatten()
6135    }
6136
6137    pub async fn enclosing_indent(
6138        &self,
6139        mut target_row: MultiBufferRow,
6140    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6141        let max_row = MultiBufferRow(self.max_point().row);
6142        if target_row >= max_row {
6143            return None;
6144        }
6145
6146        let mut target_indent = self.line_indent_for_row(target_row);
6147
6148        // If the current row is at the start of an indented block, we want to return this
6149        // block as the enclosing indent.
6150        if !target_indent.is_line_empty() && target_row < max_row {
6151            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6152            if !next_line_indent.is_line_empty()
6153                && target_indent.raw_len() < next_line_indent.raw_len()
6154            {
6155                target_indent = next_line_indent;
6156                target_row.0 += 1;
6157            }
6158        }
6159
6160        const SEARCH_ROW_LIMIT: u32 = 25000;
6161        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6162        const YIELD_INTERVAL: u32 = 100;
6163
6164        let mut accessed_row_counter = 0;
6165
6166        // If there is a blank line at the current row, search for the next non indented lines
6167        if target_indent.is_line_empty() {
6168            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6169            let end =
6170                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6171
6172            let mut non_empty_line_above = None;
6173            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6174                if row < start {
6175                    break;
6176                }
6177                accessed_row_counter += 1;
6178                if accessed_row_counter == YIELD_INTERVAL {
6179                    accessed_row_counter = 0;
6180                    yield_now().await;
6181                }
6182                if !indent.is_line_empty() {
6183                    non_empty_line_above = Some((row, indent));
6184                    break;
6185                }
6186            }
6187
6188            let mut non_empty_line_below = None;
6189            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6190                if row > end {
6191                    break;
6192                }
6193                accessed_row_counter += 1;
6194                if accessed_row_counter == YIELD_INTERVAL {
6195                    accessed_row_counter = 0;
6196                    yield_now().await;
6197                }
6198                if !indent.is_line_empty() {
6199                    non_empty_line_below = Some((row, indent));
6200                    break;
6201                }
6202            }
6203
6204            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6205                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6206                    if above_indent.raw_len() >= below_indent.raw_len() {
6207                        (above_row, above_indent)
6208                    } else {
6209                        (below_row, below_indent)
6210                    }
6211                }
6212                (Some(above), None) => above,
6213                (None, Some(below)) => below,
6214                _ => return None,
6215            };
6216
6217            target_indent = indent;
6218            target_row = row;
6219        }
6220
6221        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6222        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6223
6224        let mut start_indent = None;
6225        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6226            if row < start {
6227                break;
6228            }
6229            accessed_row_counter += 1;
6230            if accessed_row_counter == YIELD_INTERVAL {
6231                accessed_row_counter = 0;
6232                yield_now().await;
6233            }
6234            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6235                start_indent = Some((row, indent));
6236                break;
6237            }
6238        }
6239        let (start_row, start_indent_size) = start_indent?;
6240
6241        let mut end_indent = (end, None);
6242        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6243            if row > end {
6244                break;
6245            }
6246            accessed_row_counter += 1;
6247            if accessed_row_counter == YIELD_INTERVAL {
6248                accessed_row_counter = 0;
6249                yield_now().await;
6250            }
6251            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6252                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6253                break;
6254            }
6255        }
6256        let (end_row, end_indent_size) = end_indent;
6257
6258        let indent = if let Some(end_indent_size) = end_indent_size {
6259            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6260                start_indent_size
6261            } else {
6262                end_indent_size
6263            }
6264        } else {
6265            start_indent_size
6266        };
6267
6268        Some((start_row..end_row, indent))
6269    }
6270
6271    pub fn indent_guides_in_range<T: ToPoint>(
6272        &self,
6273        range: Range<T>,
6274        ignore_disabled_for_language: bool,
6275        cx: &App,
6276    ) -> impl Iterator<Item = IndentGuide> {
6277        let range = range.start.to_point(self)..range.end.to_point(self);
6278        let start_row = MultiBufferRow(range.start.row);
6279        let end_row = MultiBufferRow(range.end.row);
6280
6281        let mut row_indents = self.line_indents(start_row, |buffer| {
6282            let settings =
6283                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6284            settings.indent_guides.enabled || ignore_disabled_for_language
6285        });
6286
6287        let mut result = Vec::new();
6288        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6289
6290        let mut prev_settings = None;
6291        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6292            if first_row > end_row {
6293                break;
6294            }
6295            let current_depth = indent_stack.len() as u32;
6296
6297            // Avoid retrieving the language settings repeatedly for every buffer row.
6298            if let Some((prev_buffer_id, _)) = &prev_settings
6299                && prev_buffer_id != &buffer.remote_id()
6300            {
6301                prev_settings.take();
6302            }
6303            let settings = &prev_settings
6304                .get_or_insert_with(|| {
6305                    (
6306                        buffer.remote_id(),
6307                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6308                    )
6309                })
6310                .1;
6311            let tab_size = settings.tab_size.get();
6312
6313            // When encountering empty, continue until found useful line indent
6314            // then add to the indent stack with the depth found
6315            let mut found_indent = false;
6316            let mut last_row = first_row;
6317            if line_indent.is_line_blank() {
6318                while !found_indent {
6319                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6320                        break;
6321                    };
6322                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6323                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6324                        break;
6325                    }
6326
6327                    if new_line_indent.is_line_blank() {
6328                        continue;
6329                    }
6330                    last_row = target_row.min(end_row);
6331                    line_indent = new_line_indent;
6332                    found_indent = true;
6333                    break;
6334                }
6335            } else {
6336                found_indent = true
6337            }
6338
6339            let depth = if found_indent {
6340                line_indent.len(tab_size) / tab_size
6341            } else {
6342                0
6343            };
6344
6345            match depth.cmp(&current_depth) {
6346                cmp::Ordering::Less => {
6347                    for _ in 0..(current_depth - depth) {
6348                        let mut indent = indent_stack.pop().unwrap();
6349                        if last_row != first_row {
6350                            // In this case, we landed on an empty row, had to seek forward,
6351                            // and discovered that the indent we where on is ending.
6352                            // This means that the last display row must
6353                            // be on line that ends this indent range, so we
6354                            // should display the range up to the first non-empty line
6355                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6356                        }
6357
6358                        result.push(indent)
6359                    }
6360                }
6361                cmp::Ordering::Greater => {
6362                    for next_depth in current_depth..depth {
6363                        indent_stack.push(IndentGuide {
6364                            buffer_id: buffer.remote_id(),
6365                            start_row: first_row,
6366                            end_row: last_row,
6367                            depth: next_depth,
6368                            tab_size,
6369                            settings: settings.indent_guides.clone(),
6370                        });
6371                    }
6372                }
6373                _ => {}
6374            }
6375
6376            for indent in indent_stack.iter_mut() {
6377                indent.end_row = last_row;
6378            }
6379        }
6380
6381        result.extend(indent_stack);
6382        result.into_iter()
6383    }
6384
6385    pub fn trailing_excerpt_update_count(&self) -> usize {
6386        self.trailing_excerpt_update_count
6387    }
6388
6389    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6390        self.point_to_buffer_offset(point)
6391            .and_then(|(buffer, _)| buffer.file())
6392    }
6393
6394    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6395        self.point_to_buffer_offset(offset)
6396            .and_then(|(buffer, offset)| buffer.language_at(offset))
6397    }
6398
6399    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6400        self.excerpts
6401            .first()
6402            .map(|excerpt| &excerpt.buffer)
6403            .map(|buffer| {
6404                language_settings(
6405                    buffer.language().map(|language| language.name()),
6406                    buffer.file(),
6407                    cx,
6408                )
6409            })
6410            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6411    }
6412
6413    pub fn language_settings_at<'a, T: ToOffset>(
6414        &'a self,
6415        point: T,
6416        cx: &'a App,
6417    ) -> Cow<'a, LanguageSettings> {
6418        let mut language = None;
6419        let mut file = None;
6420        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6421            language = buffer.language_at(offset);
6422            file = buffer.file();
6423        }
6424        language_settings(language.map(|l| l.name()), file, cx)
6425    }
6426
6427    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6428        self.point_to_buffer_offset(point)
6429            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6430    }
6431
6432    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6433        self.point_to_buffer_offset(point)
6434            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6435            .unwrap_or_default()
6436    }
6437
6438    pub fn language_indent_size_at<T: ToOffset>(
6439        &self,
6440        position: T,
6441        cx: &App,
6442    ) -> Option<IndentSize> {
6443        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6444        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6445    }
6446
6447    pub fn is_dirty(&self) -> bool {
6448        self.is_dirty
6449    }
6450
6451    pub fn has_deleted_file(&self) -> bool {
6452        self.has_deleted_file
6453    }
6454
6455    pub fn has_conflict(&self) -> bool {
6456        self.has_conflict
6457    }
6458
6459    pub fn has_diagnostics(&self) -> bool {
6460        self.excerpts
6461            .iter()
6462            .any(|excerpt| excerpt.buffer.has_diagnostics())
6463    }
6464
6465    pub fn diagnostic_group(
6466        &self,
6467        buffer_id: BufferId,
6468        group_id: usize,
6469    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6470        self.lift_buffer_metadata::<Point, _, _>(
6471            Point::zero()..self.max_point(),
6472            move |buffer, range| {
6473                if buffer.remote_id() != buffer_id {
6474                    return None;
6475                };
6476                Some(
6477                    buffer
6478                        .diagnostics_in_range(range, false)
6479                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6480                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6481                )
6482            },
6483        )
6484        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6485    }
6486
6487    pub fn diagnostics_in_range<'a, MBD>(
6488        &'a self,
6489        range: Range<MBD>,
6490    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6491    where
6492        MBD::TextDimension: 'a
6493            + text::ToOffset
6494            + text::FromAnchor
6495            + Sub<Output = MBD::TextDimension>
6496            + fmt::Debug
6497            + ops::Add<Output = MBD::TextDimension>
6498            + ops::AddAssign
6499            + Ord,
6500        MBD: MultiBufferDimension
6501            + Ord
6502            + Sub<Output = MBD::TextDimension>
6503            + ops::Add<MBD::TextDimension, Output = MBD>
6504            + ops::AddAssign<MBD::TextDimension>
6505            + 'a,
6506    {
6507        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6508            Some(
6509                buffer
6510                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6511                    .map(|entry| (entry.range, entry.diagnostic)),
6512            )
6513        })
6514        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6515    }
6516
6517    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6518        &'a self,
6519        range: Range<MBD>,
6520    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6521    where
6522        MBD: MultiBufferDimension
6523            + Ord
6524            + Sub<Output = MBD::TextDimension>
6525            + ops::Add<MBD::TextDimension, Output = MBD>
6526            + ops::AddAssign<MBD::TextDimension>,
6527        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6528            + ops::Add<Output = MBD::TextDimension>
6529            + text::ToOffset
6530            + text::FromAnchor
6531            + AddAssign<MBD::TextDimension>
6532            + Ord,
6533    {
6534        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6535            Some(
6536                buffer
6537                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6538                    .map(|entry| (entry.range, entry.diagnostic)),
6539            )
6540        })
6541        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6542    }
6543
6544    pub fn syntax_ancestor<T: ToOffset>(
6545        &self,
6546        range: Range<T>,
6547    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6548        let range = range.start.to_offset(self)..range.end.to_offset(self);
6549        let mut excerpt = self.excerpt_containing(range.clone())?;
6550        let node = excerpt
6551            .buffer()
6552            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6553        let node_range = node.byte_range();
6554        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6555        if !excerpt.contains_buffer_range(node_range.clone()) {
6556            return None;
6557        };
6558        Some((node, excerpt.map_range_from_buffer(node_range)))
6559    }
6560
6561    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6562        let (excerpt_id, _, buffer) = self.as_singleton()?;
6563        let outline = buffer.outline(theme);
6564        Some(Outline::new(
6565            outline
6566                .items
6567                .into_iter()
6568                .flat_map(|item| {
6569                    Some(OutlineItem {
6570                        depth: item.depth,
6571                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6572                        source_range_for_text: self
6573                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6574                        text: item.text,
6575                        highlight_ranges: item.highlight_ranges,
6576                        name_ranges: item.name_ranges,
6577                        body_range: item.body_range.and_then(|body_range| {
6578                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6579                        }),
6580                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6581                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6582                        }),
6583                    })
6584                })
6585                .collect(),
6586        ))
6587    }
6588
6589    pub fn symbols_containing<T: ToOffset>(
6590        &self,
6591        offset: T,
6592        theme: Option<&SyntaxTheme>,
6593    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6594        let anchor = self.anchor_before(offset);
6595        let excerpt @ &Excerpt {
6596            id: excerpt_id,
6597            buffer_id,
6598            ref buffer,
6599            ..
6600        } = self.excerpt(anchor.excerpt_id)?;
6601        if cfg!(debug_assertions) {
6602            match anchor.text_anchor.buffer_id {
6603                // we clearly are hitting this according to sentry, but in what situations can this occur?
6604                Some(anchor_buffer_id) => {
6605                    assert_eq!(
6606                        anchor_buffer_id, buffer_id,
6607                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6608                    )
6609                }
6610                None => assert!(anchor.is_max()),
6611            }
6612        };
6613        Some((
6614            buffer_id,
6615            buffer
6616                .symbols_containing(anchor.text_anchor, theme)
6617                .into_iter()
6618                .flat_map(|item| {
6619                    Some(OutlineItem {
6620                        depth: item.depth,
6621                        source_range_for_text: Anchor::range_in_buffer(
6622                            excerpt_id,
6623                            item.source_range_for_text,
6624                        ),
6625                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6626                        text: item.text,
6627                        highlight_ranges: item.highlight_ranges,
6628                        name_ranges: item.name_ranges,
6629                        body_range: item
6630                            .body_range
6631                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6632                        annotation_range: item
6633                            .annotation_range
6634                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6635                    })
6636                })
6637                .collect(),
6638        ))
6639    }
6640
6641    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6642        if id == ExcerptId::min() {
6643            Locator::min_ref()
6644        } else if id == ExcerptId::max() {
6645            Locator::max_ref()
6646        } else {
6647            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6648            if let Some(entry) = item
6649                && entry.id == id
6650            {
6651                return &entry.locator;
6652            }
6653            panic!("invalid excerpt id {id:?}")
6654        }
6655    }
6656
6657    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6658    fn excerpt_locators_for_ids(
6659        &self,
6660        ids: impl IntoIterator<Item = ExcerptId>,
6661    ) -> SmallVec<[Locator; 1]> {
6662        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6663        sorted_ids.sort_unstable();
6664        sorted_ids.dedup();
6665        let mut locators = SmallVec::new();
6666
6667        while sorted_ids.last() == Some(&ExcerptId::max()) {
6668            sorted_ids.pop();
6669            locators.push(Locator::max());
6670        }
6671
6672        let mut sorted_ids = sorted_ids.into_iter().peekable();
6673        locators.extend(
6674            sorted_ids
6675                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6676                .map(|_| Locator::min()),
6677        );
6678
6679        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6680        for id in sorted_ids {
6681            if cursor.seek_forward(&id, Bias::Left) {
6682                locators.push(cursor.item().unwrap().locator.clone());
6683            } else {
6684                panic!("invalid excerpt id {:?}", id);
6685            }
6686        }
6687
6688        locators.sort_unstable();
6689        locators
6690    }
6691
6692    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6693        Some(self.excerpt(excerpt_id)?.buffer_id)
6694    }
6695
6696    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6697        Some(&self.excerpt(excerpt_id)?.buffer)
6698    }
6699
6700    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6701        let mut cursor = self
6702            .excerpts
6703            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6704        let locator = self.excerpt_locator_for_id(excerpt_id);
6705        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6706        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6707            sought_exact = true;
6708            cursor.prev();
6709        } else if excerpt_id == ExcerptId::min() {
6710            sought_exact = true;
6711        }
6712        if sought_exact {
6713            let start = cursor.start().1;
6714            let end = cursor.end().1;
6715            let mut diff_transforms = self
6716                .diff_transforms
6717                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6718            diff_transforms.seek(&start, Bias::Left);
6719            let overshoot = start - diff_transforms.start().0;
6720            let start = diff_transforms.start().1 + overshoot;
6721            diff_transforms.seek(&end, Bias::Right);
6722            let overshoot = end - diff_transforms.start().0;
6723            let end = diff_transforms.start().1 + overshoot;
6724            Some(start.0..end.0)
6725        } else {
6726            None
6727        }
6728    }
6729
6730    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6731    /// to have the latest excerpt id for the one passed in and will also remap
6732    /// `ExcerptId::max()` to the corresponding excertp ID.
6733    ///
6734    /// Callers of this function should generally use the resulting excerpt's `id` field
6735    /// afterwards.
6736    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6737        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6738        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6739        let locator = self.excerpt_locator_for_id(excerpt_id);
6740        cursor.seek(&Some(locator), Bias::Left);
6741        if let Some(excerpt) = cursor.item()
6742            && excerpt.id == excerpt_id
6743        {
6744            return Some(excerpt);
6745        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6746            cursor.prev();
6747            return cursor.item();
6748        }
6749        None
6750    }
6751
6752    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6753    pub fn excerpt_containing<T: ToOffset>(
6754        &self,
6755        range: Range<T>,
6756    ) -> Option<MultiBufferExcerpt<'_>> {
6757        let range = range.start.to_offset(self)..range.end.to_offset(self);
6758        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6759        cursor.seek(&range.start);
6760
6761        let start_excerpt = cursor.excerpt()?;
6762        if range.end != range.start {
6763            cursor.seek_forward(&range.end);
6764            if cursor.excerpt()?.id != start_excerpt.id {
6765                return None;
6766            }
6767        }
6768
6769        cursor.seek_to_start_of_current_excerpt();
6770        let region = cursor.region()?;
6771        let offset = region.range.start;
6772        let buffer_offset = start_excerpt.buffer_start_offset();
6773        let excerpt_offset = *cursor.excerpts.start();
6774        Some(MultiBufferExcerpt {
6775            diff_transforms: cursor.diff_transforms,
6776            excerpt: start_excerpt,
6777            offset,
6778            buffer_offset,
6779            excerpt_offset,
6780        })
6781    }
6782
6783    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6784        if let Some(id) = anchor.text_anchor.buffer_id {
6785            return Some(id);
6786        }
6787        let excerpt = self.excerpt_containing(anchor..anchor)?;
6788        Some(excerpt.buffer_id())
6789    }
6790
6791    pub fn selections_in_range<'a>(
6792        &'a self,
6793        range: &'a Range<Anchor>,
6794        include_local: bool,
6795    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6796        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6797        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6798        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6799        cursor.seek(start_locator, Bias::Left);
6800        cursor
6801            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6802            .flat_map(move |excerpt| {
6803                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6804                if excerpt.id == range.start.excerpt_id {
6805                    query_range.start = range.start.text_anchor;
6806                }
6807                if excerpt.id == range.end.excerpt_id {
6808                    query_range.end = range.end.text_anchor;
6809                }
6810
6811                excerpt
6812                    .buffer
6813                    .selections_in_range(query_range, include_local)
6814                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6815                        selections.map(move |selection| {
6816                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6817                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6818                            if range.start.cmp(&start, self).is_gt() {
6819                                start = range.start;
6820                            }
6821                            if range.end.cmp(&end, self).is_lt() {
6822                                end = range.end;
6823                            }
6824
6825                            (
6826                                replica_id,
6827                                line_mode,
6828                                cursor_shape,
6829                                Selection {
6830                                    id: selection.id,
6831                                    start,
6832                                    end,
6833                                    reversed: selection.reversed,
6834                                    goal: selection.goal,
6835                                },
6836                            )
6837                        })
6838                    })
6839            })
6840    }
6841
6842    pub fn show_headers(&self) -> bool {
6843        self.show_headers
6844    }
6845
6846    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6847        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6848    }
6849
6850    pub fn all_diff_hunks_expanded(&self) -> bool {
6851        self.all_diff_hunks_expanded
6852    }
6853
6854    /// Visually annotates a position or range with the `Debug` representation of a value. The
6855    /// callsite of this function is used as a key - previous annotations will be removed.
6856    #[cfg(debug_assertions)]
6857    #[track_caller]
6858    pub fn debug<V, R>(&self, ranges: &R, value: V)
6859    where
6860        R: debug::ToMultiBufferDebugRanges,
6861        V: std::fmt::Debug,
6862    {
6863        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6864    }
6865
6866    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6867    /// debug annotations with the same key will be removed. The key is also used to determine the
6868    /// annotation's color.
6869    #[cfg(debug_assertions)]
6870    #[track_caller]
6871    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6872    where
6873        K: std::hash::Hash + 'static,
6874        R: debug::ToMultiBufferDebugRanges,
6875        V: std::fmt::Debug,
6876    {
6877        let text_ranges = ranges
6878            .to_multi_buffer_debug_ranges(self)
6879            .into_iter()
6880            .flat_map(|range| {
6881                self.range_to_buffer_ranges(range.start..=range.end)
6882                    .into_iter()
6883                    .map(|(buffer, range, _excerpt_id)| {
6884                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6885                    })
6886            })
6887            .collect();
6888        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6889            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6890        });
6891    }
6892
6893    fn excerpt_edits_for_diff_change(
6894        &self,
6895        buffer_state: &BufferState,
6896        diff_change_range: Range<usize>,
6897    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6898        let mut excerpt_edits = Vec::new();
6899        for locator in &buffer_state.excerpts {
6900            let mut cursor = self
6901                .excerpts
6902                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6903            cursor.seek_forward(&Some(locator), Bias::Left);
6904            if let Some(excerpt) = cursor.item()
6905                && excerpt.locator == *locator
6906            {
6907                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6908                if diff_change_range.end < excerpt_buffer_range.start
6909                    || diff_change_range.start > excerpt_buffer_range.end
6910                {
6911                    continue;
6912                }
6913                let excerpt_start = cursor.start().1;
6914                let excerpt_len = excerpt.text_summary.len;
6915                let diff_change_start_in_excerpt = diff_change_range
6916                    .start
6917                    .saturating_sub(excerpt_buffer_range.start);
6918                let diff_change_end_in_excerpt = diff_change_range
6919                    .end
6920                    .saturating_sub(excerpt_buffer_range.start);
6921                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6922                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6923                excerpt_edits.push(Edit {
6924                    old: edit_start..edit_end,
6925                    new: edit_start..edit_end,
6926                });
6927            }
6928        }
6929        excerpt_edits
6930    }
6931}
6932
6933#[cfg(any(test, feature = "test-support"))]
6934impl MultiBufferSnapshot {
6935    pub fn random_byte_range(
6936        &self,
6937        start_offset: MultiBufferOffset,
6938        rng: &mut impl rand::Rng,
6939    ) -> Range<MultiBufferOffset> {
6940        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6941        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6942        start..end
6943    }
6944
6945    #[cfg(any(test, feature = "test-support"))]
6946    fn check_invariants(&self) {
6947        let excerpts = self.excerpts.items(());
6948        let excerpt_ids = self.excerpt_ids.items(());
6949
6950        for (ix, excerpt) in excerpts.iter().enumerate() {
6951            if ix == 0 {
6952                if excerpt.locator <= Locator::min() {
6953                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6954                }
6955            } else if excerpt.locator <= excerpts[ix - 1].locator {
6956                panic!("excerpts are out-of-order: {:?}", excerpts);
6957            }
6958        }
6959
6960        for (ix, entry) in excerpt_ids.iter().enumerate() {
6961            if ix == 0 {
6962                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6963                    panic!("invalid first excerpt id {:?}", entry.id);
6964                }
6965            } else if entry.id <= excerpt_ids[ix - 1].id {
6966                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6967            }
6968        }
6969
6970        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6971            panic!(
6972                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6973                self.excerpts.summary().text,
6974                self.diff_transforms.summary().input,
6975                self.diff_transforms.items(()),
6976            );
6977        }
6978
6979        let mut prev_transform: Option<&DiffTransform> = None;
6980        for item in self.diff_transforms.iter() {
6981            if let DiffTransform::BufferContent {
6982                summary,
6983                inserted_hunk_info,
6984            } = item
6985            {
6986                if let Some(DiffTransform::BufferContent {
6987                    inserted_hunk_info: prev_inserted_hunk_info,
6988                    ..
6989                }) = prev_transform
6990                    && *inserted_hunk_info == *prev_inserted_hunk_info
6991                {
6992                    panic!(
6993                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6994                        self.diff_transforms.items(())
6995                    );
6996                }
6997                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6998                    panic!("empty buffer content transform");
6999                }
7000            }
7001            prev_transform = Some(item);
7002        }
7003    }
7004}
7005
7006impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7007where
7008    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7009    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7010{
7011    #[instrument(skip_all)]
7012    fn seek(&mut self, position: &MBD) {
7013        let position = OutputDimension(*position);
7014        self.cached_region.take();
7015        self.diff_transforms.seek(&position, Bias::Right);
7016        if self.diff_transforms.item().is_none()
7017            && self.diff_transforms.start().output_dimension == position
7018        {
7019            self.diff_transforms.prev();
7020        }
7021
7022        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7023        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7024            let overshoot = position - self.diff_transforms.start().output_dimension;
7025            excerpt_position += overshoot;
7026        }
7027
7028        self.excerpts.seek(&excerpt_position, Bias::Right);
7029        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7030            self.excerpts.prev();
7031        }
7032    }
7033
7034    fn seek_forward(&mut self, position: &MBD) {
7035        let position = OutputDimension(*position);
7036        self.cached_region.take();
7037        self.diff_transforms.seek_forward(&position, Bias::Right);
7038        if self.diff_transforms.item().is_none()
7039            && self.diff_transforms.start().output_dimension == position
7040        {
7041            self.diff_transforms.prev();
7042        }
7043
7044        let overshoot = position - self.diff_transforms.start().output_dimension;
7045        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7046        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7047            excerpt_position += overshoot;
7048        }
7049
7050        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7051        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7052            self.excerpts.prev();
7053        }
7054    }
7055
7056    fn next_excerpt(&mut self) {
7057        self.excerpts.next();
7058        self.seek_to_start_of_current_excerpt();
7059    }
7060
7061    fn prev_excerpt(&mut self) {
7062        self.excerpts.prev();
7063        self.seek_to_start_of_current_excerpt();
7064    }
7065
7066    fn seek_to_start_of_current_excerpt(&mut self) {
7067        self.cached_region.take();
7068
7069        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7070            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7071            && self.diff_transforms.next_item().is_some()
7072        {
7073            self.diff_transforms.next();
7074        }
7075    }
7076
7077    fn next_excerpt_forwards(&mut self) {
7078        self.excerpts.next();
7079        self.seek_to_start_of_current_excerpt_forward();
7080    }
7081
7082    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7083        self.cached_region.take();
7084
7085        if self
7086            .diff_transforms
7087            .seek_forward(self.excerpts.start(), Bias::Left)
7088            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7089            && self.diff_transforms.next_item().is_some()
7090        {
7091            self.diff_transforms.next();
7092        }
7093    }
7094
7095    fn next(&mut self) {
7096        self.cached_region.take();
7097        match self
7098            .diff_transforms
7099            .end()
7100            .excerpt_dimension
7101            .cmp(&self.excerpts.end())
7102        {
7103            cmp::Ordering::Less => self.diff_transforms.next(),
7104            cmp::Ordering::Greater => self.excerpts.next(),
7105            cmp::Ordering::Equal => {
7106                self.diff_transforms.next();
7107                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7108                    || self.diff_transforms.item().is_none()
7109                {
7110                    self.excerpts.next();
7111                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7112                    self.diff_transforms.item()
7113                    && self
7114                        .excerpts
7115                        .item()
7116                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7117                {
7118                    self.excerpts.next();
7119                }
7120            }
7121        }
7122    }
7123
7124    fn prev(&mut self) {
7125        self.cached_region.take();
7126        match self
7127            .diff_transforms
7128            .start()
7129            .excerpt_dimension
7130            .cmp(self.excerpts.start())
7131        {
7132            cmp::Ordering::Less => self.excerpts.prev(),
7133            cmp::Ordering::Greater => self.diff_transforms.prev(),
7134            cmp::Ordering::Equal => {
7135                self.diff_transforms.prev();
7136                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7137                    || self.diff_transforms.item().is_none()
7138                {
7139                    self.excerpts.prev();
7140                }
7141            }
7142        }
7143    }
7144
7145    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7146        self.cached_region
7147            .get_or_init(|| self.build_region())
7148            .as_ref()
7149    }
7150
7151    fn is_at_start_of_excerpt(&mut self) -> bool {
7152        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7153            return false;
7154        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7155            return true;
7156        }
7157
7158        self.diff_transforms.prev();
7159        let prev_transform = self.diff_transforms.item();
7160        self.diff_transforms.next();
7161
7162        prev_transform.is_none_or(|next_transform| {
7163            matches!(next_transform, DiffTransform::BufferContent { .. })
7164        })
7165    }
7166
7167    fn is_at_end_of_excerpt(&self) -> bool {
7168        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7169            return false;
7170        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7171            || self.diff_transforms.item().is_none()
7172        {
7173            return true;
7174        }
7175
7176        let next_transform = self.diff_transforms.next_item();
7177        next_transform.is_none_or(|next_transform| match next_transform {
7178            DiffTransform::BufferContent { .. } => true,
7179            DiffTransform::DeletedHunk { hunk_info, .. } => self
7180                .excerpts
7181                .item()
7182                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7183        })
7184    }
7185
7186    fn main_buffer_position(&self) -> Option<BD> {
7187        let excerpt = self.excerpts.item()?;
7188        let buffer = &excerpt.buffer;
7189        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7190        let mut buffer_start = buffer_context_start;
7191        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7192        buffer_start += overshoot;
7193        Some(buffer_start)
7194    }
7195
7196    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7197        let excerpt = self.excerpts.item()?;
7198        match self.diff_transforms.item()? {
7199            DiffTransform::DeletedHunk {
7200                buffer_id,
7201                base_text_byte_range,
7202                has_trailing_newline,
7203                hunk_info,
7204                ..
7205            } => {
7206                let diff = self.diffs.get(buffer_id)?;
7207                let buffer = diff.base_text();
7208                let mut rope_cursor = buffer.as_rope().cursor(0);
7209                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7210                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7211                let mut buffer_end = buffer_start;
7212                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7213                let start = self.diff_transforms.start().output_dimension.0;
7214                let end = self.diff_transforms.end().output_dimension.0;
7215                Some(MultiBufferRegion {
7216                    buffer,
7217                    excerpt,
7218                    has_trailing_newline: *has_trailing_newline,
7219                    is_main_buffer: false,
7220                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7221                        hunk_info.hunk_secondary_status,
7222                    )),
7223                    buffer_range: buffer_start..buffer_end,
7224                    range: start..end,
7225                })
7226            }
7227            DiffTransform::BufferContent {
7228                inserted_hunk_info, ..
7229            } => {
7230                let buffer = &excerpt.buffer;
7231                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7232
7233                let mut start = self.diff_transforms.start().output_dimension.0;
7234                let mut buffer_start = buffer_context_start;
7235                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7236                    let overshoot =
7237                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7238                    start += overshoot;
7239                } else {
7240                    let overshoot =
7241                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7242                    buffer_start += overshoot;
7243                }
7244
7245                let mut end;
7246                let mut buffer_end;
7247                let has_trailing_newline;
7248                let transform_end = self.diff_transforms.end();
7249                if transform_end.excerpt_dimension < self.excerpts.end() {
7250                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7251                    end = transform_end.output_dimension.0;
7252                    buffer_end = buffer_context_start;
7253                    buffer_end += overshoot;
7254                    has_trailing_newline = false;
7255                } else {
7256                    let overshoot =
7257                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7258                    end = self.diff_transforms.start().output_dimension.0;
7259                    end += overshoot;
7260                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7261                    has_trailing_newline = excerpt.has_trailing_newline;
7262                };
7263
7264                let diff_hunk_status = inserted_hunk_info.map(|info| {
7265                    if info.is_logically_deleted {
7266                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7267                    } else {
7268                        DiffHunkStatus::added(info.hunk_secondary_status)
7269                    }
7270                });
7271
7272                Some(MultiBufferRegion {
7273                    buffer,
7274                    excerpt,
7275                    has_trailing_newline,
7276                    is_main_buffer: true,
7277                    diff_hunk_status,
7278                    buffer_range: buffer_start..buffer_end,
7279                    range: start..end,
7280                })
7281            }
7282        }
7283    }
7284
7285    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7286        let excerpt = self.excerpts.item()?;
7287        match self.diff_transforms.item()? {
7288            &DiffTransform::DeletedHunk { .. } => {
7289                let start = self.diff_transforms.start().output_dimension.0;
7290                let end = self.diff_transforms.end().output_dimension.0;
7291                Some((excerpt, start..end))
7292            }
7293            DiffTransform::BufferContent { .. } => {
7294                let mut start = self.diff_transforms.start().output_dimension.0;
7295                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7296                    let overshoot =
7297                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7298                    start += overshoot;
7299                }
7300
7301                let mut end;
7302                let transform_end = self.diff_transforms.end();
7303                if transform_end.excerpt_dimension < self.excerpts.end() {
7304                    end = transform_end.output_dimension.0;
7305                } else {
7306                    let overshoot =
7307                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7308                    end = self.diff_transforms.start().output_dimension.0;
7309                    end += overshoot;
7310                };
7311
7312                Some((excerpt, start..end))
7313            }
7314        }
7315    }
7316
7317    fn excerpt(&self) -> Option<&'a Excerpt> {
7318        self.excerpts.item()
7319    }
7320}
7321
7322impl Excerpt {
7323    fn new(
7324        id: ExcerptId,
7325        locator: Locator,
7326        buffer_id: BufferId,
7327        buffer: Arc<BufferSnapshot>,
7328        range: ExcerptRange<text::Anchor>,
7329        has_trailing_newline: bool,
7330    ) -> Self {
7331        Excerpt {
7332            id,
7333            locator,
7334            max_buffer_row: range.context.end.to_point(&buffer).row,
7335            text_summary: buffer
7336                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7337            buffer_id,
7338            buffer,
7339            range,
7340            has_trailing_newline,
7341        }
7342    }
7343
7344    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7345        let content_start = self.range.context.start.to_offset(&self.buffer);
7346        let chunks_start = content_start + range.start;
7347        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7348
7349        let has_footer = self.has_trailing_newline
7350            && range.start <= self.text_summary.len
7351            && range.end > self.text_summary.len;
7352
7353        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7354
7355        ExcerptChunks {
7356            excerpt_id: self.id,
7357            content_chunks,
7358            has_footer,
7359        }
7360    }
7361
7362    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7363        let content_start = self.range.context.start.to_offset(&self.buffer);
7364        let chunks_start = content_start + range.start;
7365        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7366        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7367        excerpt_chunks.has_footer = self.has_trailing_newline
7368            && range.start <= self.text_summary.len
7369            && range.end > self.text_summary.len;
7370    }
7371
7372    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7373        if text_anchor
7374            .cmp(&self.range.context.start, &self.buffer)
7375            .is_lt()
7376        {
7377            self.range.context.start
7378        } else if text_anchor
7379            .cmp(&self.range.context.end, &self.buffer)
7380            .is_gt()
7381        {
7382            self.range.context.end
7383        } else {
7384            text_anchor
7385        }
7386    }
7387
7388    fn contains(&self, anchor: &Anchor) -> bool {
7389        (anchor.text_anchor.buffer_id == None
7390            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7391            && self
7392                .range
7393                .context
7394                .start
7395                .cmp(&anchor.text_anchor, &self.buffer)
7396                .is_le()
7397            && self
7398                .range
7399                .context
7400                .end
7401                .cmp(&anchor.text_anchor, &self.buffer)
7402                .is_ge()
7403    }
7404
7405    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7406    fn buffer_start_offset(&self) -> BufferOffset {
7407        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7408    }
7409
7410    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7411    fn buffer_end_offset(&self) -> BufferOffset {
7412        self.buffer_start_offset() + self.text_summary.len
7413    }
7414}
7415
7416impl<'a> MultiBufferExcerpt<'a> {
7417    pub fn id(&self) -> ExcerptId {
7418        self.excerpt.id
7419    }
7420
7421    pub fn buffer_id(&self) -> BufferId {
7422        self.excerpt.buffer_id
7423    }
7424
7425    pub fn start_anchor(&self) -> Anchor {
7426        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7427    }
7428
7429    pub fn end_anchor(&self) -> Anchor {
7430        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7431    }
7432
7433    pub fn buffer(&self) -> &'a BufferSnapshot {
7434        &self.excerpt.buffer
7435    }
7436
7437    pub fn buffer_range(&self) -> Range<BufferOffset> {
7438        self.buffer_offset
7439            ..BufferOffset(
7440                self.excerpt
7441                    .range
7442                    .context
7443                    .end
7444                    .to_offset(&self.excerpt.buffer.text),
7445            )
7446    }
7447
7448    pub fn start_offset(&self) -> MultiBufferOffset {
7449        self.offset
7450    }
7451
7452    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7453    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7454        self.map_range_to_buffer(offset..offset).start
7455    }
7456
7457    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7458    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7459        self.diff_transforms
7460            .seek(&OutputDimension(range.start), Bias::Right);
7461        let start = self.map_offset_to_buffer_internal(range.start);
7462        let end = if range.end > range.start {
7463            self.diff_transforms
7464                .seek_forward(&OutputDimension(range.end), Bias::Right);
7465            self.map_offset_to_buffer_internal(range.end)
7466        } else {
7467            start
7468        };
7469        start..end
7470    }
7471
7472    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7473        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7474        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7475            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7476        };
7477        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7478        self.buffer_offset + offset_in_excerpt
7479    }
7480
7481    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7482    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7483        self.map_range_from_buffer(buffer_offset..buffer_offset)
7484            .start
7485    }
7486
7487    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7488    pub fn map_range_from_buffer(
7489        &mut self,
7490        buffer_range: Range<BufferOffset>,
7491    ) -> Range<MultiBufferOffset> {
7492        if buffer_range.start < self.buffer_offset {
7493            log::warn!(
7494                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7495            );
7496            return self.offset..self.offset;
7497        }
7498        let overshoot = buffer_range.start - self.buffer_offset;
7499        let excerpt_offset = self.excerpt_offset + overshoot;
7500        let excerpt_seek_dim = excerpt_offset;
7501        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7502        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7503            log::warn!(
7504                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7505            );
7506            return self.offset..self.offset;
7507        }
7508        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7509        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7510
7511        let end = if buffer_range.start < buffer_range.end {
7512            let overshoot = buffer_range.end - self.buffer_offset;
7513            let excerpt_offset = self.excerpt_offset + overshoot;
7514            let excerpt_seek_dim = excerpt_offset;
7515            self.diff_transforms
7516                .seek_forward(&excerpt_seek_dim, Bias::Right);
7517            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7518            // todo(lw): Clamp end to the excerpt boundaries
7519            self.diff_transforms.start().output_dimension.0 + overshoot
7520        } else {
7521            start
7522        };
7523
7524        start..end
7525    }
7526
7527    /// Returns true if the entirety of the given range is in the buffer's excerpt
7528    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7529        range.start >= self.excerpt.buffer_start_offset()
7530            && range.end <= self.excerpt.buffer_end_offset()
7531    }
7532
7533    /// Returns true if any part of the given range is in the buffer's excerpt
7534    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7535        range.start <= self.excerpt.buffer_end_offset()
7536            && range.end >= self.excerpt.buffer_start_offset()
7537    }
7538
7539    pub fn max_buffer_row(&self) -> u32 {
7540        self.excerpt.max_buffer_row
7541    }
7542}
7543
7544impl ExcerptId {
7545    pub fn min() -> Self {
7546        Self(0)
7547    }
7548
7549    pub fn max() -> Self {
7550        Self(u32::MAX)
7551    }
7552
7553    pub fn to_proto(self) -> u64 {
7554        self.0 as _
7555    }
7556
7557    pub fn from_proto(proto: u64) -> Self {
7558        Self(proto as _)
7559    }
7560
7561    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7562        let a = snapshot.excerpt_locator_for_id(*self);
7563        let b = snapshot.excerpt_locator_for_id(*other);
7564        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7565    }
7566}
7567
7568impl From<ExcerptId> for usize {
7569    fn from(val: ExcerptId) -> Self {
7570        val.0 as usize
7571    }
7572}
7573
7574impl fmt::Debug for Excerpt {
7575    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7576        f.debug_struct("Excerpt")
7577            .field("id", &self.id)
7578            .field("locator", &self.locator)
7579            .field("buffer_id", &self.buffer_id)
7580            .field("range", &self.range)
7581            .field("text_summary", &self.text_summary)
7582            .field("has_trailing_newline", &self.has_trailing_newline)
7583            .finish()
7584    }
7585}
7586
7587impl sum_tree::Item for Excerpt {
7588    type Summary = ExcerptSummary;
7589
7590    fn summary(&self, _cx: ()) -> Self::Summary {
7591        let mut text = self.text_summary;
7592        if self.has_trailing_newline {
7593            text += TextSummary::from("\n");
7594        }
7595        ExcerptSummary {
7596            excerpt_id: self.id,
7597            excerpt_locator: self.locator.clone(),
7598            widest_line_number: self.max_buffer_row,
7599            text: text.into(),
7600        }
7601    }
7602}
7603
7604impl sum_tree::Item for ExcerptIdMapping {
7605    type Summary = ExcerptId;
7606
7607    fn summary(&self, _cx: ()) -> Self::Summary {
7608        self.id
7609    }
7610}
7611
7612impl sum_tree::KeyedItem for ExcerptIdMapping {
7613    type Key = ExcerptId;
7614
7615    fn key(&self) -> Self::Key {
7616        self.id
7617    }
7618}
7619
7620impl DiffTransform {
7621    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7622        match self {
7623            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7624            DiffTransform::BufferContent {
7625                inserted_hunk_info, ..
7626            } => *inserted_hunk_info,
7627        }
7628    }
7629}
7630
7631impl sum_tree::Item for DiffTransform {
7632    type Summary = DiffTransformSummary;
7633
7634    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7635        match self {
7636            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7637                input: *summary,
7638                output: *summary,
7639            },
7640            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7641                input: MBTextSummary::default(),
7642                output: summary.into(),
7643            },
7644        }
7645    }
7646}
7647
7648impl DiffTransformSummary {
7649    fn excerpt_len(&self) -> ExcerptOffset {
7650        ExcerptDimension(self.input.len)
7651    }
7652}
7653
7654impl sum_tree::ContextLessSummary for DiffTransformSummary {
7655    fn zero() -> Self {
7656        DiffTransformSummary {
7657            input: MBTextSummary::default(),
7658            output: MBTextSummary::default(),
7659        }
7660    }
7661
7662    fn add_summary(&mut self, other: &Self) {
7663        self.input += other.input;
7664        self.output += other.output;
7665    }
7666}
7667
7668impl sum_tree::ContextLessSummary for ExcerptId {
7669    fn zero() -> Self {
7670        Self(0)
7671    }
7672
7673    fn add_summary(&mut self, summary: &Self) {
7674        *self = cmp::max(*self, *summary);
7675    }
7676}
7677
7678impl sum_tree::ContextLessSummary for ExcerptSummary {
7679    fn zero() -> Self {
7680        Self::default()
7681    }
7682
7683    fn add_summary(&mut self, summary: &Self) {
7684        debug_assert!(
7685            summary.excerpt_locator > self.excerpt_locator
7686                || self.excerpt_locator == Locator::min(),
7687            "Excerpt locators must be in ascending order: {:?} > {:?}",
7688            summary.excerpt_locator,
7689            self.excerpt_locator
7690        );
7691        self.excerpt_locator = summary.excerpt_locator.clone();
7692        self.text += summary.text;
7693        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7694    }
7695}
7696
7697impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7698    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7699        Ord::cmp(&Some(self), cursor_location)
7700    }
7701}
7702
7703impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7704    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7705        Ord::cmp(self, &cursor_location.excerpt_locator)
7706    }
7707}
7708
7709impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7710where
7711    MBD: MultiBufferDimension + Default,
7712{
7713    fn zero(_: ()) -> Self {
7714        ExcerptDimension(MBD::default())
7715    }
7716
7717    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7718        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7719    }
7720}
7721
7722impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7723    fn zero(_cx: ()) -> Self {
7724        Default::default()
7725    }
7726
7727    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7728        *self = Some(&summary.excerpt_locator);
7729    }
7730}
7731
7732impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7733    fn zero(_cx: ()) -> Self {
7734        Default::default()
7735    }
7736
7737    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7738        *self = Some(summary.excerpt_id);
7739    }
7740}
7741
7742#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7743struct OutputDimension<T>(T);
7744
7745impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7746    fn eq(&self, other: &T) -> bool {
7747        self.0 == *other
7748    }
7749}
7750
7751impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7752    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7753        self.0.partial_cmp(other)
7754    }
7755}
7756
7757impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7758where
7759    T: ops::Sub<U, Output = R>,
7760{
7761    type Output = R;
7762
7763    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7764        self.0 - other.0
7765    }
7766}
7767
7768impl<R, T, U> ops::Add<U> for OutputDimension<T>
7769where
7770    T: ops::Add<U, Output = R>,
7771{
7772    type Output = OutputDimension<R>;
7773
7774    fn add(self, other: U) -> Self::Output {
7775        OutputDimension(self.0 + other)
7776    }
7777}
7778
7779impl<T, U> AddAssign<U> for OutputDimension<T>
7780where
7781    T: AddAssign<U>,
7782{
7783    fn add_assign(&mut self, other: U) {
7784        self.0 += other;
7785    }
7786}
7787
7788impl<T, U> SubAssign<U> for OutputDimension<T>
7789where
7790    T: SubAssign<U>,
7791{
7792    fn sub_assign(&mut self, other: U) {
7793        self.0 -= other;
7794    }
7795}
7796
7797#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7798struct ExcerptDimension<T>(T);
7799
7800impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7801    fn eq(&self, other: &T) -> bool {
7802        self.0 == *other
7803    }
7804}
7805
7806impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7807    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7808        self.0.partial_cmp(other)
7809    }
7810}
7811
7812impl ExcerptOffset {
7813    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7814        self.0.saturating_sub(other.0)
7815    }
7816}
7817
7818impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7819where
7820    T: ops::Sub<U, Output = R>,
7821{
7822    type Output = R;
7823
7824    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7825        self.0 - other.0
7826    }
7827}
7828
7829impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7830where
7831    T: ops::Add<U, Output = R>,
7832{
7833    type Output = ExcerptDimension<R>;
7834
7835    fn add(self, other: U) -> Self::Output {
7836        ExcerptDimension(self.0 + other)
7837    }
7838}
7839
7840impl<T, U> AddAssign<U> for ExcerptDimension<T>
7841where
7842    T: AddAssign<U>,
7843{
7844    fn add_assign(&mut self, other: U) {
7845        self.0 += other;
7846    }
7847}
7848
7849impl<T, U> SubAssign<U> for ExcerptDimension<T>
7850where
7851    T: SubAssign<U>,
7852{
7853    fn sub_assign(&mut self, other: U) {
7854        self.0 -= other;
7855    }
7856}
7857
7858impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7859    fn zero(_: ()) -> Self {
7860        MultiBufferOffset::ZERO
7861    }
7862
7863    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7864        *self += summary.output.len;
7865    }
7866}
7867
7868impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7869    for ExcerptDimension<MBD>
7870where
7871    MBD: MultiBufferDimension + Ord,
7872{
7873    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7874        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7875    }
7876}
7877
7878impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7879    for ExcerptDimension<MBD>
7880where
7881    MBD: MultiBufferDimension + Ord,
7882{
7883    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7884        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7885    }
7886}
7887
7888impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7889    for ExcerptDimension<MBD>
7890{
7891    fn zero(_: ()) -> Self {
7892        ExcerptDimension(MBD::default())
7893    }
7894
7895    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7896        self.0.add_mb_text_summary(&summary.input)
7897    }
7898}
7899
7900impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7901    for OutputDimension<MBD>
7902where
7903    MBD: MultiBufferDimension + Ord,
7904{
7905    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7906        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7907    }
7908}
7909
7910impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7911    for OutputDimension<MBD>
7912{
7913    fn zero(_: ()) -> Self {
7914        OutputDimension(MBD::default())
7915    }
7916
7917    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7918        self.0.add_mb_text_summary(&summary.output)
7919    }
7920}
7921
7922impl MultiBufferRows<'_> {
7923    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7924        self.point = Point::new(row, 0);
7925        self.cursor.seek(&self.point);
7926    }
7927}
7928
7929impl Iterator for MultiBufferRows<'_> {
7930    type Item = RowInfo;
7931
7932    fn next(&mut self) -> Option<Self::Item> {
7933        if self.is_empty && self.point.row == 0 {
7934            self.point += Point::new(1, 0);
7935            return Some(RowInfo {
7936                buffer_id: None,
7937                buffer_row: Some(0),
7938                multibuffer_row: Some(MultiBufferRow(0)),
7939                diff_status: None,
7940                expand_info: None,
7941                wrapped_buffer_row: None,
7942            });
7943        }
7944
7945        let mut region = self.cursor.region()?.clone();
7946        while self.point >= region.range.end {
7947            self.cursor.next();
7948            if let Some(next_region) = self.cursor.region() {
7949                region = next_region.clone();
7950            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7951                let multibuffer_row = MultiBufferRow(self.point.row);
7952                let last_excerpt = self
7953                    .cursor
7954                    .excerpts
7955                    .item()
7956                    .or(self.cursor.excerpts.prev_item())?;
7957                let last_row = last_excerpt
7958                    .range
7959                    .context
7960                    .end
7961                    .to_point(&last_excerpt.buffer)
7962                    .row;
7963
7964                let first_row = last_excerpt
7965                    .range
7966                    .context
7967                    .start
7968                    .to_point(&last_excerpt.buffer)
7969                    .row;
7970
7971                let expand_info = if self.is_singleton {
7972                    None
7973                } else {
7974                    let needs_expand_up = first_row == last_row
7975                        && last_row > 0
7976                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7977                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7978
7979                    if needs_expand_up && needs_expand_down {
7980                        Some(ExpandExcerptDirection::UpAndDown)
7981                    } else if needs_expand_up {
7982                        Some(ExpandExcerptDirection::Up)
7983                    } else if needs_expand_down {
7984                        Some(ExpandExcerptDirection::Down)
7985                    } else {
7986                        None
7987                    }
7988                    .map(|direction| ExpandInfo {
7989                        direction,
7990                        excerpt_id: last_excerpt.id,
7991                    })
7992                };
7993                self.point += Point::new(1, 0);
7994                return Some(RowInfo {
7995                    buffer_id: Some(last_excerpt.buffer_id),
7996                    buffer_row: Some(last_row),
7997                    multibuffer_row: Some(multibuffer_row),
7998                    diff_status: None,
7999                    wrapped_buffer_row: None,
8000                    expand_info,
8001                });
8002            } else {
8003                return None;
8004            };
8005        }
8006
8007        let overshoot = self.point - region.range.start;
8008        let buffer_point = region.buffer_range.start + overshoot;
8009        let expand_info = if self.is_singleton {
8010            None
8011        } else {
8012            let needs_expand_up = self.point.row == region.range.start.row
8013                && self.cursor.is_at_start_of_excerpt()
8014                && buffer_point.row > 0;
8015            let needs_expand_down = (region.excerpt.has_trailing_newline
8016                && self.point.row + 1 == region.range.end.row
8017                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8018                && self.cursor.is_at_end_of_excerpt()
8019                && buffer_point.row < region.buffer.max_point().row;
8020
8021            if needs_expand_up && needs_expand_down {
8022                Some(ExpandExcerptDirection::UpAndDown)
8023            } else if needs_expand_up {
8024                Some(ExpandExcerptDirection::Up)
8025            } else if needs_expand_down {
8026                Some(ExpandExcerptDirection::Down)
8027            } else {
8028                None
8029            }
8030            .map(|direction| ExpandInfo {
8031                direction,
8032                excerpt_id: region.excerpt.id,
8033            })
8034        };
8035
8036        let result = Some(RowInfo {
8037            buffer_id: Some(region.buffer.remote_id()),
8038            buffer_row: Some(buffer_point.row),
8039            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8040            diff_status: region
8041                .diff_hunk_status
8042                .filter(|_| self.point < region.range.end),
8043            expand_info,
8044            wrapped_buffer_row: None,
8045        });
8046        self.point += Point::new(1, 0);
8047        result
8048    }
8049}
8050
8051impl<'a> MultiBufferChunks<'a> {
8052    pub fn offset(&self) -> MultiBufferOffset {
8053        self.range.start
8054    }
8055
8056    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8057        self.diff_transforms.seek(&range.end, Bias::Right);
8058        let mut excerpt_end = self.diff_transforms.start().1;
8059        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8060            let overshoot = range.end - self.diff_transforms.start().0;
8061            excerpt_end += overshoot;
8062        }
8063
8064        self.diff_transforms.seek(&range.start, Bias::Right);
8065        let mut excerpt_start = self.diff_transforms.start().1;
8066        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8067            let overshoot = range.start - self.diff_transforms.start().0;
8068            excerpt_start += overshoot;
8069        }
8070
8071        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8072        self.buffer_chunk.take();
8073        self.range = range;
8074    }
8075
8076    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8077        self.excerpt_offset_range = new_range.clone();
8078        self.excerpts.seek(&new_range.start, Bias::Right);
8079        if let Some(excerpt) = self.excerpts.item() {
8080            let excerpt_start = *self.excerpts.start();
8081            if let Some(excerpt_chunks) = self
8082                .excerpt_chunks
8083                .as_mut()
8084                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8085            {
8086                excerpt.seek_chunks(
8087                    excerpt_chunks,
8088                    (self.excerpt_offset_range.start - excerpt_start)
8089                        ..(self.excerpt_offset_range.end - excerpt_start),
8090                );
8091            } else {
8092                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8093                    (self.excerpt_offset_range.start - excerpt_start)
8094                        ..(self.excerpt_offset_range.end - excerpt_start),
8095                    self.language_aware,
8096                ));
8097            }
8098        } else {
8099            self.excerpt_chunks = None;
8100        }
8101    }
8102
8103    #[ztracing::instrument(skip_all)]
8104    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8105        loop {
8106            if self.excerpt_offset_range.is_empty() {
8107                return None;
8108            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8109                self.excerpt_offset_range.start += chunk.text.len();
8110                return Some(chunk);
8111            } else {
8112                self.excerpts.next();
8113                let excerpt = self.excerpts.item()?;
8114                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8115                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8116                    self.language_aware,
8117                ));
8118            }
8119        }
8120    }
8121}
8122
8123impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8124    type Item = &'a str;
8125
8126    fn next(&mut self) -> Option<Self::Item> {
8127        let mut region = self.cursor.region()?;
8128        if self.offset == region.range.start {
8129            self.cursor.prev();
8130            region = self.cursor.region()?;
8131            let start_overshoot = self.start.saturating_sub(region.range.start);
8132            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8133                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8134            ));
8135        }
8136
8137        if self.offset == region.range.end && region.has_trailing_newline {
8138            self.offset -= 1;
8139            Some("\n")
8140        } else {
8141            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8142            self.offset -= chunk.len();
8143            Some(chunk)
8144        }
8145    }
8146}
8147
8148impl<'a> Iterator for MultiBufferChunks<'a> {
8149    type Item = Chunk<'a>;
8150
8151    #[ztracing::instrument(skip_all)]
8152    fn next(&mut self) -> Option<Chunk<'a>> {
8153        if self.range.start >= self.range.end {
8154            return None;
8155        }
8156        if self.range.start == self.diff_transforms.end().0 {
8157            self.diff_transforms.next();
8158        }
8159
8160        let diff_transform_start = self.diff_transforms.start().0;
8161        let diff_transform_end = self.diff_transforms.end().0;
8162        debug_assert!(
8163            self.range.start < diff_transform_end,
8164            "{:?} < {:?} of ({1:?}..{2:?})",
8165            self.range.start,
8166            diff_transform_end,
8167            diff_transform_start
8168        );
8169
8170        let diff_transform = self.diff_transforms.item()?;
8171        match diff_transform {
8172            DiffTransform::BufferContent { .. } => {
8173                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8174                    chunk
8175                } else {
8176                    let chunk = self.next_excerpt_chunk().unwrap();
8177                    self.buffer_chunk.insert(chunk)
8178                };
8179
8180                let chunk_end = self.range.start + chunk.text.len();
8181                let diff_transform_end = diff_transform_end.min(self.range.end);
8182
8183                if diff_transform_end < chunk_end {
8184                    let split_idx = diff_transform_end - self.range.start;
8185                    let (before, after) = chunk.text.split_at(split_idx);
8186                    self.range.start = diff_transform_end;
8187                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8188                    let chars = chunk.chars & mask;
8189                    let tabs = chunk.tabs & mask;
8190
8191                    chunk.text = after;
8192                    chunk.chars = chunk.chars >> split_idx;
8193                    chunk.tabs = chunk.tabs >> split_idx;
8194
8195                    Some(Chunk {
8196                        text: before,
8197                        chars,
8198                        tabs,
8199                        ..chunk.clone()
8200                    })
8201                } else {
8202                    self.range.start = chunk_end;
8203                    self.buffer_chunk.take()
8204                }
8205            }
8206            DiffTransform::DeletedHunk {
8207                buffer_id,
8208                base_text_byte_range,
8209                has_trailing_newline,
8210                ..
8211            } => {
8212                let base_text_start =
8213                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8214                let base_text_end =
8215                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8216                let base_text_end = base_text_end.min(base_text_byte_range.end);
8217
8218                let mut chunks = if let Some((_, mut chunks)) = self
8219                    .diff_base_chunks
8220                    .take()
8221                    .filter(|(id, _)| id == buffer_id)
8222                {
8223                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8224                    {
8225                        chunks.seek(base_text_start..base_text_end);
8226                    }
8227                    chunks
8228                } else {
8229                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8230                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8231                };
8232
8233                let chunk = if let Some(chunk) = chunks.next() {
8234                    self.range.start += chunk.text.len();
8235                    self.diff_base_chunks = Some((*buffer_id, chunks));
8236                    chunk
8237                } else {
8238                    debug_assert!(has_trailing_newline);
8239                    self.range.start += "\n".len();
8240                    Chunk {
8241                        text: "\n",
8242                        chars: 1u128,
8243                        ..Default::default()
8244                    }
8245                };
8246                Some(chunk)
8247            }
8248        }
8249    }
8250}
8251
8252impl MultiBufferBytes<'_> {
8253    fn consume(&mut self, len: usize) {
8254        self.range.start += len;
8255        self.chunk = &self.chunk[len..];
8256
8257        if !self.range.is_empty() && self.chunk.is_empty() {
8258            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8259                self.chunk = chunk;
8260            } else if self.has_trailing_newline {
8261                self.has_trailing_newline = false;
8262                self.chunk = b"\n";
8263            } else {
8264                self.cursor.next();
8265                if let Some(region) = self.cursor.region() {
8266                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8267                        region.buffer_range.start
8268                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8269                                .min(region.buffer_range.end),
8270                    );
8271                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8272                    self.excerpt_bytes = Some(excerpt_bytes);
8273                    self.has_trailing_newline =
8274                        region.has_trailing_newline && self.range.end >= region.range.end;
8275                    if self.chunk.is_empty() && self.has_trailing_newline {
8276                        self.has_trailing_newline = false;
8277                        self.chunk = b"\n";
8278                    }
8279                }
8280            }
8281        }
8282    }
8283}
8284
8285impl<'a> Iterator for MultiBufferBytes<'a> {
8286    type Item = &'a [u8];
8287
8288    fn next(&mut self) -> Option<Self::Item> {
8289        let chunk = self.chunk;
8290        if chunk.is_empty() {
8291            None
8292        } else {
8293            self.consume(chunk.len());
8294            Some(chunk)
8295        }
8296    }
8297}
8298
8299impl io::Read for MultiBufferBytes<'_> {
8300    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8301        let len = cmp::min(buf.len(), self.chunk.len());
8302        buf[..len].copy_from_slice(&self.chunk[..len]);
8303        if len > 0 {
8304            self.consume(len);
8305        }
8306        Ok(len)
8307    }
8308}
8309
8310impl io::Read for ReversedMultiBufferBytes<'_> {
8311    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8312        let len = cmp::min(buf.len(), self.chunk.len());
8313        buf[..len].copy_from_slice(&self.chunk[..len]);
8314        buf[..len].reverse();
8315        if len > 0 {
8316            self.range.end -= len;
8317            self.chunk = &self.chunk[..self.chunk.len() - len];
8318            if !self.range.is_empty()
8319                && self.chunk.is_empty()
8320                && let Some(chunk) = self.chunks.next()
8321            {
8322                self.chunk = chunk.as_bytes();
8323            }
8324        }
8325        Ok(len)
8326    }
8327}
8328
8329impl<'a> Iterator for ExcerptChunks<'a> {
8330    type Item = Chunk<'a>;
8331
8332    fn next(&mut self) -> Option<Self::Item> {
8333        if let Some(chunk) = self.content_chunks.next() {
8334            return Some(chunk);
8335        }
8336
8337        if self.has_footer {
8338            let text = "\n";
8339            let chars = 0b1;
8340            self.has_footer = false;
8341            return Some(Chunk {
8342                text,
8343                chars,
8344                ..Default::default()
8345            });
8346        }
8347
8348        None
8349    }
8350}
8351
8352impl ToOffset for Point {
8353    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8354        snapshot.point_to_offset(*self)
8355    }
8356    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8357        snapshot.point_to_offset_utf16(*self)
8358    }
8359}
8360
8361impl ToOffset for MultiBufferOffset {
8362    #[track_caller]
8363    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8364        assert!(
8365            *self <= snapshot.len(),
8366            "offset {} is greater than the snapshot.len() {}",
8367            self.0,
8368            snapshot.len().0,
8369        );
8370        *self
8371    }
8372    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8373        snapshot.offset_to_offset_utf16(*self)
8374    }
8375}
8376
8377impl ToOffset for MultiBufferOffsetUtf16 {
8378    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8379        snapshot.offset_utf16_to_offset(*self)
8380    }
8381
8382    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8383        *self
8384    }
8385}
8386
8387impl ToOffset for PointUtf16 {
8388    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8389        snapshot.point_utf16_to_offset(*self)
8390    }
8391    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8392        snapshot.point_utf16_to_offset_utf16(*self)
8393    }
8394}
8395
8396impl ToPoint for MultiBufferOffset {
8397    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8398        snapshot.offset_to_point(*self)
8399    }
8400    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8401        snapshot.offset_to_point_utf16(*self)
8402    }
8403}
8404
8405impl ToPoint for Point {
8406    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8407        *self
8408    }
8409    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8410        snapshot.point_to_point_utf16(*self)
8411    }
8412}
8413
8414impl ToPoint for PointUtf16 {
8415    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8416        snapshot.point_utf16_to_point(*self)
8417    }
8418    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8419        *self
8420    }
8421}
8422
8423impl From<ExcerptId> for EntityId {
8424    fn from(id: ExcerptId) -> Self {
8425        EntityId::from(id.0 as u64)
8426    }
8427}
8428
8429#[cfg(debug_assertions)]
8430pub mod debug {
8431    use super::*;
8432
8433    pub trait ToMultiBufferDebugRanges {
8434        fn to_multi_buffer_debug_ranges(
8435            &self,
8436            snapshot: &MultiBufferSnapshot,
8437        ) -> Vec<Range<MultiBufferOffset>>;
8438    }
8439
8440    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8441        fn to_multi_buffer_debug_ranges(
8442            &self,
8443            snapshot: &MultiBufferSnapshot,
8444        ) -> Vec<Range<MultiBufferOffset>> {
8445            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8446        }
8447    }
8448
8449    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8450        fn to_multi_buffer_debug_ranges(
8451            &self,
8452            snapshot: &MultiBufferSnapshot,
8453        ) -> Vec<Range<MultiBufferOffset>> {
8454            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8455                .to_multi_buffer_debug_ranges(snapshot)
8456        }
8457    }
8458
8459    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8460        fn to_multi_buffer_debug_ranges(
8461            &self,
8462            snapshot: &MultiBufferSnapshot,
8463        ) -> Vec<Range<MultiBufferOffset>> {
8464            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8465        }
8466    }
8467
8468    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8469        fn to_multi_buffer_debug_ranges(
8470            &self,
8471            snapshot: &MultiBufferSnapshot,
8472        ) -> Vec<Range<MultiBufferOffset>> {
8473            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8474        }
8475    }
8476
8477    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8478        fn to_multi_buffer_debug_ranges(
8479            &self,
8480            snapshot: &MultiBufferSnapshot,
8481        ) -> Vec<Range<MultiBufferOffset>> {
8482            self.iter()
8483                .map(|item| {
8484                    let offset = item.to_offset(snapshot);
8485                    offset..offset
8486                })
8487                .collect()
8488        }
8489    }
8490
8491    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8492        fn to_multi_buffer_debug_ranges(
8493            &self,
8494            snapshot: &MultiBufferSnapshot,
8495        ) -> Vec<Range<MultiBufferOffset>> {
8496            self.iter()
8497                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8498                .collect()
8499        }
8500    }
8501}