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, DiffHunkSecondaryStatus,
  14    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::{PathExcerptInsertResult, 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    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    main_buffer: Option<Entity<language::Buffer>>,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    main_buffer: Option<language::BufferSnapshot>,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            main_buffer: None,
 577        }
 578    }
 579
 580    fn new_inverted(
 581        diff: Entity<BufferDiff>,
 582        main_buffer: Entity<language::Buffer>,
 583        cx: &mut Context<MultiBuffer>,
 584    ) -> Self {
 585        let weak_main_buffer = main_buffer.downgrade();
 586        DiffState {
 587            _subscription: cx.subscribe(&diff, {
 588                move |this, diff, event, cx| {
 589                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 590                        return;
 591                    };
 592                    match event {
 593                        BufferDiffEvent::DiffChanged(DiffChanged {
 594                            changed_range: _,
 595                            base_text_changed_range,
 596                            extended_range: _,
 597                        }) => {
 598                            if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 599                                this.inverted_buffer_diff_changed(
 600                                    diff,
 601                                    main_buffer,
 602                                    base_text_changed_range,
 603                                    cx,
 604                                )
 605                            }
 606                            cx.emit(Event::BufferDiffChanged);
 607                        }
 608                        BufferDiffEvent::LanguageChanged => {
 609                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 610                        }
 611                        _ => {}
 612                    }
 613                }
 614            }),
 615            diff,
 616            main_buffer: Some(main_buffer),
 617        }
 618    }
 619}
 620
 621/// The contents of a [`MultiBuffer`] at a single point in time.
 622#[derive(Clone, Default)]
 623pub struct MultiBufferSnapshot {
 624    excerpts: SumTree<Excerpt>,
 625    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 626    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 627    diff_transforms: SumTree<DiffTransform>,
 628    excerpt_ids: SumTree<ExcerptIdMapping>,
 629    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 630    non_text_state_update_count: usize,
 631    edit_count: usize,
 632    is_dirty: bool,
 633    has_deleted_file: bool,
 634    has_conflict: bool,
 635    has_inverted_diff: bool,
 636    singleton: bool,
 637    trailing_excerpt_update_count: usize,
 638    all_diff_hunks_expanded: bool,
 639    show_deleted_hunks: bool,
 640    use_extended_diff_range: bool,
 641    show_headers: bool,
 642}
 643
 644// follower: None
 645// - BufferContent(Some)
 646// - BufferContent(None)
 647// - DeletedHunk
 648//
 649// follower: Some
 650// - BufferContent(Some)
 651// - BufferContent(None)
 652
 653#[derive(Debug, Clone)]
 654enum DiffTransform {
 655    // RealText
 656    BufferContent {
 657        summary: MBTextSummary,
 658        // modified_hunk_info
 659        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 660    },
 661    // ExpandedHunkText
 662    DeletedHunk {
 663        summary: TextSummary,
 664        buffer_id: BufferId,
 665        hunk_info: DiffTransformHunkInfo,
 666        base_text_byte_range: Range<usize>,
 667        has_trailing_newline: bool,
 668    },
 669}
 670
 671#[derive(Clone, Copy, Debug)]
 672struct DiffTransformHunkInfo {
 673    excerpt_id: ExcerptId,
 674    hunk_start_anchor: text::Anchor,
 675    hunk_secondary_status: DiffHunkSecondaryStatus,
 676    is_logically_deleted: bool,
 677}
 678
 679impl Eq for DiffTransformHunkInfo {}
 680
 681impl PartialEq for DiffTransformHunkInfo {
 682    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 683        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 684    }
 685}
 686
 687impl std::hash::Hash for DiffTransformHunkInfo {
 688    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 689        self.excerpt_id.hash(state);
 690        self.hunk_start_anchor.hash(state);
 691    }
 692}
 693
 694#[derive(Clone)]
 695pub struct ExcerptInfo {
 696    pub id: ExcerptId,
 697    pub buffer: Arc<BufferSnapshot>,
 698    pub buffer_id: BufferId,
 699    pub range: ExcerptRange<text::Anchor>,
 700    pub end_row: MultiBufferRow,
 701}
 702
 703impl std::fmt::Debug for ExcerptInfo {
 704    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 705        f.debug_struct(type_name::<Self>())
 706            .field("id", &self.id)
 707            .field("buffer_id", &self.buffer_id)
 708            .field("path", &self.buffer.file().map(|f| f.path()))
 709            .field("range", &self.range)
 710            .finish()
 711    }
 712}
 713
 714/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 715#[derive(Debug)]
 716pub struct ExcerptBoundary {
 717    pub prev: Option<ExcerptInfo>,
 718    pub next: ExcerptInfo,
 719    /// The row in the `MultiBuffer` where the boundary is located
 720    pub row: MultiBufferRow,
 721}
 722
 723impl ExcerptBoundary {
 724    pub fn starts_new_buffer(&self) -> bool {
 725        match (self.prev.as_ref(), &self.next) {
 726            (None, _) => true,
 727            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 728        }
 729    }
 730}
 731
 732#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 733pub struct ExpandInfo {
 734    pub direction: ExpandExcerptDirection,
 735    pub excerpt_id: ExcerptId,
 736}
 737
 738#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 739pub struct RowInfo {
 740    pub buffer_id: Option<BufferId>,
 741    pub buffer_row: Option<u32>,
 742    pub multibuffer_row: Option<MultiBufferRow>,
 743    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 744    pub expand_info: Option<ExpandInfo>,
 745    pub wrapped_buffer_row: Option<u32>,
 746}
 747
 748/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 749#[derive(Clone)]
 750struct Excerpt {
 751    /// The unique identifier for this excerpt
 752    id: ExcerptId,
 753    /// The location of the excerpt in the [`MultiBuffer`]
 754    locator: Locator,
 755    /// The buffer being excerpted
 756    buffer_id: BufferId,
 757    /// A snapshot of the buffer being excerpted
 758    buffer: Arc<BufferSnapshot>,
 759    /// The range of the buffer to be shown in the excerpt
 760    range: ExcerptRange<text::Anchor>,
 761    /// The last row in the excerpted slice of the buffer
 762    max_buffer_row: BufferRow,
 763    /// A summary of the text in the excerpt
 764    text_summary: TextSummary,
 765    has_trailing_newline: bool,
 766}
 767
 768/// A public view into an `Excerpt` in a [`MultiBuffer`].
 769///
 770/// Contains methods for getting the [`Buffer`] of the excerpt,
 771/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 772#[derive(Clone)]
 773pub struct MultiBufferExcerpt<'a> {
 774    excerpt: &'a Excerpt,
 775    diff_transforms:
 776        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 777    /// The offset in the multibuffer considering diff transforms.
 778    offset: MultiBufferOffset,
 779    /// The offset in the multibuffer without diff transforms.
 780    excerpt_offset: ExcerptOffset,
 781    buffer_offset: BufferOffset,
 782}
 783
 784#[derive(Clone, Debug)]
 785struct ExcerptIdMapping {
 786    id: ExcerptId,
 787    locator: Locator,
 788}
 789
 790/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 791/// These ranges are relative to the buffer itself
 792#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 793pub struct ExcerptRange<T> {
 794    /// The full range of text to be shown in the excerpt.
 795    pub context: Range<T>,
 796    /// The primary range of text to be highlighted in the excerpt.
 797    /// In a multi-buffer search, this would be the text that matched the search
 798    pub primary: Range<T>,
 799}
 800
 801impl<T: Clone> ExcerptRange<T> {
 802    pub fn new(context: Range<T>) -> Self {
 803        Self {
 804            context: context.clone(),
 805            primary: context,
 806        }
 807    }
 808}
 809
 810#[derive(Clone, Debug, Default)]
 811pub struct ExcerptSummary {
 812    excerpt_id: ExcerptId,
 813    /// The location of the last [`Excerpt`] being summarized
 814    excerpt_locator: Locator,
 815    widest_line_number: u32,
 816    text: MBTextSummary,
 817}
 818
 819#[derive(Debug, Clone)]
 820pub struct DiffTransformSummary {
 821    input: MBTextSummary,
 822    output: MBTextSummary,
 823}
 824
 825/// Summary of a string of text.
 826#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 827pub struct MBTextSummary {
 828    /// Length in bytes.
 829    pub len: MultiBufferOffset,
 830    /// Length in UTF-8.
 831    pub chars: usize,
 832    /// Length in UTF-16 code units
 833    pub len_utf16: OffsetUtf16,
 834    /// A point representing the number of lines and the length of the last line.
 835    ///
 836    /// In other words, it marks the point after the last byte in the text, (if
 837    /// EOF was a character, this would be its position).
 838    pub lines: Point,
 839    /// How many `char`s are in the first line
 840    pub first_line_chars: u32,
 841    /// How many `char`s are in the last line
 842    pub last_line_chars: u32,
 843    /// How many UTF-16 code units are in the last line
 844    pub last_line_len_utf16: u32,
 845    /// The row idx of the longest row
 846    pub longest_row: u32,
 847    /// How many `char`s are in the longest row
 848    pub longest_row_chars: u32,
 849}
 850
 851impl From<TextSummary> for MBTextSummary {
 852    fn from(summary: TextSummary) -> Self {
 853        MBTextSummary {
 854            len: MultiBufferOffset(summary.len),
 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<MBTextSummary> for TextSummary {
 868    fn from(summary: MBTextSummary) -> Self {
 869        TextSummary {
 870            len: summary.len.0,
 871            chars: summary.chars,
 872            len_utf16: summary.len_utf16,
 873            lines: summary.lines,
 874            first_line_chars: summary.first_line_chars,
 875            last_line_chars: summary.last_line_chars,
 876            last_line_len_utf16: summary.last_line_len_utf16,
 877            longest_row: summary.longest_row,
 878            longest_row_chars: summary.longest_row_chars,
 879        }
 880    }
 881}
 882
 883impl From<&str> for MBTextSummary {
 884    fn from(text: &str) -> Self {
 885        MBTextSummary::from(TextSummary::from(text))
 886    }
 887}
 888
 889impl MultiBufferDimension for MBTextSummary {
 890    type TextDimension = TextSummary;
 891
 892    fn from_summary(summary: &MBTextSummary) -> Self {
 893        *summary
 894    }
 895
 896    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 897        *self += *summary;
 898    }
 899
 900    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 901        *self += *summary;
 902    }
 903}
 904
 905impl AddAssign for MBTextSummary {
 906    fn add_assign(&mut self, other: MBTextSummary) {
 907        let joined_chars = self.last_line_chars + other.first_line_chars;
 908        if joined_chars > self.longest_row_chars {
 909            self.longest_row = self.lines.row;
 910            self.longest_row_chars = joined_chars;
 911        }
 912        if other.longest_row_chars > self.longest_row_chars {
 913            self.longest_row = self.lines.row + other.longest_row;
 914            self.longest_row_chars = other.longest_row_chars;
 915        }
 916
 917        if self.lines.row == 0 {
 918            self.first_line_chars += other.first_line_chars;
 919        }
 920
 921        if other.lines.row == 0 {
 922            self.last_line_chars += other.first_line_chars;
 923            self.last_line_len_utf16 += other.last_line_len_utf16;
 924        } else {
 925            self.last_line_chars = other.last_line_chars;
 926            self.last_line_len_utf16 = other.last_line_len_utf16;
 927        }
 928
 929        self.chars += other.chars;
 930        self.len += other.len;
 931        self.len_utf16 += other.len_utf16;
 932        self.lines += other.lines;
 933    }
 934}
 935
 936impl AddAssign<TextSummary> for MBTextSummary {
 937    fn add_assign(&mut self, other: TextSummary) {
 938        *self += MBTextSummary::from(other);
 939    }
 940}
 941
 942impl MBTextSummary {
 943    pub fn lines_utf16(&self) -> PointUtf16 {
 944        PointUtf16 {
 945            row: self.lines.row,
 946            column: self.last_line_len_utf16,
 947        }
 948    }
 949}
 950
 951impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 952where
 953    K: MultiBufferDimension,
 954    V: MultiBufferDimension,
 955{
 956    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 957
 958    fn from_summary(summary: &MBTextSummary) -> Self {
 959        Self {
 960            key: K::from_summary(summary),
 961            value: Some(V::from_summary(summary)),
 962        }
 963    }
 964
 965    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 966        self.key.add_text_dim(&summary.key);
 967        if let Some(value) = &mut self.value {
 968            if let Some(other_value) = summary.value.as_ref() {
 969                value.add_text_dim(other_value);
 970            }
 971        }
 972    }
 973
 974    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 975        self.key.add_mb_text_summary(summary);
 976        if let Some(value) = &mut self.value {
 977            value.add_mb_text_summary(summary);
 978        }
 979    }
 980}
 981
 982#[derive(Clone)]
 983pub struct MultiBufferRows<'a> {
 984    point: Point,
 985    is_empty: bool,
 986    is_singleton: bool,
 987    cursor: MultiBufferCursor<'a, Point, Point>,
 988}
 989
 990pub struct MultiBufferChunks<'a> {
 991    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 992    diff_transforms:
 993        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 994    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 995    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 996    buffer_chunk: Option<Chunk<'a>>,
 997    range: Range<MultiBufferOffset>,
 998    excerpt_offset_range: Range<ExcerptOffset>,
 999    excerpt_chunks: Option<ExcerptChunks<'a>>,
1000    language_aware: bool,
1001}
1002
1003pub struct ReversedMultiBufferChunks<'a> {
1004    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1005    current_chunks: Option<rope::Chunks<'a>>,
1006    start: MultiBufferOffset,
1007    offset: MultiBufferOffset,
1008}
1009
1010pub struct MultiBufferBytes<'a> {
1011    range: Range<MultiBufferOffset>,
1012    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1013    excerpt_bytes: Option<text::Bytes<'a>>,
1014    has_trailing_newline: bool,
1015    chunk: &'a [u8],
1016}
1017
1018pub struct ReversedMultiBufferBytes<'a> {
1019    range: Range<MultiBufferOffset>,
1020    chunks: ReversedMultiBufferChunks<'a>,
1021    chunk: &'a [u8],
1022}
1023
1024#[derive(Clone)]
1025struct DiffTransforms<MBD> {
1026    output_dimension: OutputDimension<MBD>,
1027    excerpt_dimension: ExcerptDimension<MBD>,
1028}
1029
1030impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1031    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1032        Self {
1033            output_dimension: OutputDimension::zero(cx),
1034            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1035                cx,
1036            ),
1037        }
1038    }
1039
1040    fn add_summary(
1041        &mut self,
1042        summary: &'a DiffTransformSummary,
1043        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1044    ) {
1045        self.output_dimension.add_summary(summary, cx);
1046        self.excerpt_dimension.add_summary(summary, cx);
1047    }
1048}
1049
1050#[derive(Clone)]
1051struct MultiBufferCursor<'a, MBD, BD> {
1052    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1053    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1054    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1055    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1056}
1057
1058#[derive(Clone)]
1059struct MultiBufferRegion<'a, MBD, BD> {
1060    buffer: &'a BufferSnapshot,
1061    is_main_buffer: bool,
1062    diff_hunk_status: Option<DiffHunkStatus>,
1063    excerpt: &'a Excerpt,
1064    buffer_range: Range<BD>,
1065    range: Range<MBD>,
1066    has_trailing_newline: bool,
1067}
1068
1069struct ExcerptChunks<'a> {
1070    excerpt_id: ExcerptId,
1071    content_chunks: BufferChunks<'a>,
1072    has_footer: bool,
1073}
1074
1075#[derive(Debug)]
1076struct BufferEdit {
1077    range: Range<BufferOffset>,
1078    new_text: Arc<str>,
1079    is_insertion: bool,
1080    original_indent_column: Option<u32>,
1081    excerpt_id: ExcerptId,
1082}
1083
1084#[derive(Clone, Copy, Debug, PartialEq)]
1085enum DiffChangeKind {
1086    BufferEdited,
1087    DiffUpdated { base_changed: bool },
1088    ExpandOrCollapseHunks { expand: bool },
1089}
1090
1091#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1092pub enum ExpandExcerptDirection {
1093    Up,
1094    Down,
1095    UpAndDown,
1096}
1097
1098impl ExpandExcerptDirection {
1099    pub fn should_expand_up(&self) -> bool {
1100        match self {
1101            ExpandExcerptDirection::Up => true,
1102            ExpandExcerptDirection::Down => false,
1103            ExpandExcerptDirection::UpAndDown => true,
1104        }
1105    }
1106
1107    pub fn should_expand_down(&self) -> bool {
1108        match self {
1109            ExpandExcerptDirection::Up => false,
1110            ExpandExcerptDirection::Down => true,
1111            ExpandExcerptDirection::UpAndDown => true,
1112        }
1113    }
1114}
1115
1116#[derive(Clone, Debug, PartialEq)]
1117pub struct IndentGuide {
1118    pub buffer_id: BufferId,
1119    pub start_row: MultiBufferRow,
1120    pub end_row: MultiBufferRow,
1121    pub depth: u32,
1122    pub tab_size: u32,
1123    pub settings: IndentGuideSettings,
1124}
1125
1126impl IndentGuide {
1127    pub fn indent_level(&self) -> u32 {
1128        self.depth * self.tab_size
1129    }
1130}
1131
1132impl MultiBuffer {
1133    pub fn new(capability: Capability) -> Self {
1134        Self::new_(
1135            capability,
1136            MultiBufferSnapshot {
1137                show_headers: true,
1138                show_deleted_hunks: true,
1139                ..MultiBufferSnapshot::default()
1140            },
1141        )
1142    }
1143
1144    pub fn without_headers(capability: Capability) -> Self {
1145        Self::new_(
1146            capability,
1147            MultiBufferSnapshot {
1148                show_deleted_hunks: true,
1149                ..MultiBufferSnapshot::default()
1150            },
1151        )
1152    }
1153
1154    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1155        let mut this = Self::new_(
1156            buffer.read(cx).capability(),
1157            MultiBufferSnapshot {
1158                singleton: true,
1159                show_deleted_hunks: true,
1160                ..MultiBufferSnapshot::default()
1161            },
1162        );
1163        this.singleton = true;
1164        let buffer_id = buffer.read(cx).remote_id();
1165        this.push_excerpts(
1166            buffer,
1167            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1168                buffer_id,
1169            ))],
1170            cx,
1171        );
1172        this
1173    }
1174
1175    #[inline]
1176    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1177        Self {
1178            snapshot: RefCell::new(snapshot),
1179            buffers: Default::default(),
1180            diffs: HashMap::default(),
1181            subscriptions: Topic::default(),
1182            singleton: false,
1183            capability,
1184            title: None,
1185            excerpts_by_path: Default::default(),
1186            paths_by_excerpt: Default::default(),
1187            buffer_changed_since_sync: Default::default(),
1188            history: History::default(),
1189        }
1190    }
1191
1192    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1193        let mut buffers = BTreeMap::default();
1194        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1195        for (buffer_id, buffer_state) in self.buffers.iter() {
1196            buffer_state.buffer.update(new_cx, |buffer, _| {
1197                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1198            });
1199            buffers.insert(
1200                *buffer_id,
1201                BufferState {
1202                    buffer: buffer_state.buffer.clone(),
1203                    last_version: buffer_state.last_version.clone(),
1204                    last_non_text_state_update_count: buffer_state
1205                        .last_non_text_state_update_count
1206                        .clone(),
1207                    excerpts: buffer_state.excerpts.clone(),
1208                    _subscriptions: [
1209                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1210                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1211                    ],
1212                },
1213            );
1214        }
1215        let mut diff_bases = HashMap::default();
1216        for (buffer_id, diff) in self.diffs.iter() {
1217            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1218        }
1219        Self {
1220            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1221            buffers,
1222            excerpts_by_path: Default::default(),
1223            paths_by_excerpt: Default::default(),
1224            diffs: diff_bases,
1225            subscriptions: Default::default(),
1226            singleton: self.singleton,
1227            capability: self.capability,
1228            history: self.history.clone(),
1229            title: self.title.clone(),
1230            buffer_changed_since_sync,
1231        }
1232    }
1233
1234    pub fn set_group_interval(&mut self, group_interval: Duration) {
1235        self.history.set_group_interval(group_interval);
1236    }
1237
1238    pub fn with_title(mut self, title: String) -> Self {
1239        self.title = Some(title);
1240        self
1241    }
1242
1243    pub fn read_only(&self) -> bool {
1244        !self.capability.editable()
1245    }
1246
1247    pub fn capability(&self) -> Capability {
1248        self.capability
1249    }
1250
1251    /// Returns an up-to-date snapshot of the MultiBuffer.
1252    #[ztracing::instrument(skip_all)]
1253    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1254        self.sync(cx);
1255        self.snapshot.borrow().clone()
1256    }
1257
1258    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1259        self.sync(cx);
1260        self.snapshot.borrow()
1261    }
1262
1263    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1264        if self.singleton {
1265            Some(self.buffers.values().next().unwrap().buffer.clone())
1266        } else {
1267            None
1268        }
1269    }
1270
1271    pub fn is_singleton(&self) -> bool {
1272        self.singleton
1273    }
1274
1275    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1276        self.subscriptions.subscribe()
1277    }
1278
1279    pub fn is_dirty(&self, cx: &App) -> bool {
1280        self.read(cx).is_dirty()
1281    }
1282
1283    pub fn has_deleted_file(&self, cx: &App) -> bool {
1284        self.read(cx).has_deleted_file()
1285    }
1286
1287    pub fn has_conflict(&self, cx: &App) -> bool {
1288        self.read(cx).has_conflict()
1289    }
1290
1291    // The `is_empty` signature doesn't match what clippy expects
1292    #[allow(clippy::len_without_is_empty)]
1293    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1294        self.read(cx).len()
1295    }
1296
1297    pub fn is_empty(&self) -> bool {
1298        self.buffers.is_empty()
1299    }
1300
1301    pub fn edit<I, S, T>(
1302        &mut self,
1303        edits: I,
1304        autoindent_mode: Option<AutoindentMode>,
1305        cx: &mut Context<Self>,
1306    ) where
1307        I: IntoIterator<Item = (Range<S>, T)>,
1308        S: ToOffset,
1309        T: Into<Arc<str>>,
1310    {
1311        self.edit_internal(edits, autoindent_mode, true, cx);
1312    }
1313
1314    pub fn edit_non_coalesce<I, S, T>(
1315        &mut self,
1316        edits: I,
1317        autoindent_mode: Option<AutoindentMode>,
1318        cx: &mut Context<Self>,
1319    ) where
1320        I: IntoIterator<Item = (Range<S>, T)>,
1321        S: ToOffset,
1322        T: Into<Arc<str>>,
1323    {
1324        self.edit_internal(edits, autoindent_mode, false, cx);
1325    }
1326
1327    fn edit_internal<I, S, T>(
1328        &mut self,
1329        edits: I,
1330        autoindent_mode: Option<AutoindentMode>,
1331        coalesce_adjacent: bool,
1332        cx: &mut Context<Self>,
1333    ) where
1334        I: IntoIterator<Item = (Range<S>, T)>,
1335        S: ToOffset,
1336        T: Into<Arc<str>>,
1337    {
1338        if self.read_only() || self.buffers.is_empty() {
1339            return;
1340        }
1341        self.sync_mut(cx);
1342        let edits = edits
1343            .into_iter()
1344            .map(|(range, new_text)| {
1345                let mut range = range.start.to_offset(self.snapshot.get_mut())
1346                    ..range.end.to_offset(self.snapshot.get_mut());
1347                if range.start > range.end {
1348                    mem::swap(&mut range.start, &mut range.end);
1349                }
1350                (range, new_text.into())
1351            })
1352            .collect::<Vec<_>>();
1353
1354        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1355
1356        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1357        fn edit_internal(
1358            this: &mut MultiBuffer,
1359            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1360            mut autoindent_mode: Option<AutoindentMode>,
1361            coalesce_adjacent: bool,
1362            cx: &mut Context<MultiBuffer>,
1363        ) {
1364            let original_indent_columns = match &mut autoindent_mode {
1365                Some(AutoindentMode::Block {
1366                    original_indent_columns,
1367                }) => mem::take(original_indent_columns),
1368                _ => Default::default(),
1369            };
1370
1371            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1372                edits,
1373                this.snapshot.get_mut(),
1374                &original_indent_columns,
1375            );
1376
1377            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1378            for (buffer_id, mut edits) in buffer_edits {
1379                buffer_ids.push(buffer_id);
1380                edits.sort_by_key(|edit| edit.range.start);
1381                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1382                    let mut edits = edits.into_iter().peekable();
1383                    let mut insertions = Vec::new();
1384                    let mut original_indent_columns = Vec::new();
1385                    let mut deletions = Vec::new();
1386                    let empty_str: Arc<str> = Arc::default();
1387                    while let Some(BufferEdit {
1388                        mut range,
1389                        mut new_text,
1390                        mut is_insertion,
1391                        original_indent_column,
1392                        excerpt_id,
1393                    }) = edits.next()
1394                    {
1395                        while let Some(BufferEdit {
1396                            range: next_range,
1397                            is_insertion: next_is_insertion,
1398                            new_text: next_new_text,
1399                            excerpt_id: next_excerpt_id,
1400                            ..
1401                        }) = edits.peek()
1402                        {
1403                            let should_coalesce = if coalesce_adjacent {
1404                                range.end >= next_range.start
1405                            } else {
1406                                range.end > next_range.start
1407                            };
1408
1409                            if should_coalesce {
1410                                range.end = cmp::max(next_range.end, range.end);
1411                                is_insertion |= *next_is_insertion;
1412                                if excerpt_id == *next_excerpt_id {
1413                                    new_text = format!("{new_text}{next_new_text}").into();
1414                                }
1415                                edits.next();
1416                            } else {
1417                                break;
1418                            }
1419                        }
1420
1421                        if is_insertion {
1422                            original_indent_columns.push(original_indent_column);
1423                            insertions.push((
1424                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1425                                new_text.clone(),
1426                            ));
1427                        } else if !range.is_empty() {
1428                            deletions.push((
1429                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1430                                empty_str.clone(),
1431                            ));
1432                        }
1433                    }
1434
1435                    let deletion_autoindent_mode =
1436                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1437                            Some(AutoindentMode::Block {
1438                                original_indent_columns: Default::default(),
1439                            })
1440                        } else {
1441                            autoindent_mode.clone()
1442                        };
1443                    let insertion_autoindent_mode =
1444                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1445                            Some(AutoindentMode::Block {
1446                                original_indent_columns,
1447                            })
1448                        } else {
1449                            autoindent_mode.clone()
1450                        };
1451
1452                    if coalesce_adjacent {
1453                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1454                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1455                    } else {
1456                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1457                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1458                    }
1459                })
1460            }
1461
1462            cx.emit(Event::ExcerptsEdited {
1463                excerpt_ids: edited_excerpt_ids,
1464                buffer_ids,
1465            });
1466        }
1467    }
1468
1469    fn convert_edits_to_buffer_edits(
1470        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1471        snapshot: &MultiBufferSnapshot,
1472        original_indent_columns: &[Option<u32>],
1473    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1474        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1475        let mut edited_excerpt_ids = Vec::new();
1476        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1477        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1478            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1479
1480            cursor.seek(&range.start);
1481            let mut start_region = cursor.region().expect("start offset out of bounds");
1482            if !start_region.is_main_buffer {
1483                cursor.next();
1484                if let Some(region) = cursor.region() {
1485                    start_region = region;
1486                } else {
1487                    continue;
1488                }
1489            }
1490
1491            if range.end < start_region.range.start {
1492                continue;
1493            }
1494
1495            let start_region = start_region.clone();
1496            if range.end > start_region.range.end {
1497                cursor.seek_forward(&range.end);
1498            }
1499            let mut end_region = cursor.region().expect("end offset out of bounds");
1500            if !end_region.is_main_buffer {
1501                cursor.prev();
1502                if let Some(region) = cursor.region() {
1503                    end_region = region;
1504                } else {
1505                    continue;
1506                }
1507            }
1508
1509            if range.start > end_region.range.end {
1510                continue;
1511            }
1512
1513            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1514            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1515            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1516                .min(start_region.buffer_range.end);
1517            let buffer_end =
1518                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1519
1520            if start_region.excerpt.id == end_region.excerpt.id {
1521                if start_region.buffer.capability == Capability::ReadWrite
1522                    && start_region.is_main_buffer
1523                {
1524                    edited_excerpt_ids.push(start_region.excerpt.id);
1525                    buffer_edits
1526                        .entry(start_region.buffer.remote_id())
1527                        .or_default()
1528                        .push(BufferEdit {
1529                            range: buffer_start..buffer_end,
1530                            new_text,
1531                            is_insertion: true,
1532                            original_indent_column,
1533                            excerpt_id: start_region.excerpt.id,
1534                        });
1535                }
1536            } else {
1537                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1538                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1539                if start_region.buffer.capability == Capability::ReadWrite
1540                    && start_region.is_main_buffer
1541                {
1542                    edited_excerpt_ids.push(start_region.excerpt.id);
1543                    buffer_edits
1544                        .entry(start_region.buffer.remote_id())
1545                        .or_default()
1546                        .push(BufferEdit {
1547                            range: start_excerpt_range,
1548                            new_text: new_text.clone(),
1549                            is_insertion: true,
1550                            original_indent_column,
1551                            excerpt_id: start_region.excerpt.id,
1552                        });
1553                }
1554                let excerpt_id = end_region.excerpt.id;
1555                if end_region.buffer.capability == Capability::ReadWrite
1556                    && end_region.is_main_buffer
1557                {
1558                    edited_excerpt_ids.push(excerpt_id);
1559                    buffer_edits
1560                        .entry(end_region.buffer.remote_id())
1561                        .or_default()
1562                        .push(BufferEdit {
1563                            range: end_excerpt_range,
1564                            new_text: new_text.clone(),
1565                            is_insertion: false,
1566                            original_indent_column,
1567                            excerpt_id,
1568                        });
1569                }
1570
1571                cursor.seek(&range.start);
1572                cursor.next_excerpt();
1573                while let Some(region) = cursor.region() {
1574                    if region.excerpt.id == excerpt_id {
1575                        break;
1576                    }
1577                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1578                        edited_excerpt_ids.push(region.excerpt.id);
1579                        buffer_edits
1580                            .entry(region.buffer.remote_id())
1581                            .or_default()
1582                            .push(BufferEdit {
1583                                range: region.buffer_range.clone(),
1584                                new_text: new_text.clone(),
1585                                is_insertion: false,
1586                                original_indent_column,
1587                                excerpt_id: region.excerpt.id,
1588                            });
1589                    }
1590                    cursor.next_excerpt();
1591                }
1592            }
1593        }
1594        (buffer_edits, edited_excerpt_ids)
1595    }
1596
1597    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1598    where
1599        I: IntoIterator<Item = Range<S>>,
1600        S: ToOffset,
1601    {
1602        if self.read_only() || self.buffers.is_empty() {
1603            return;
1604        }
1605        self.sync_mut(cx);
1606        let empty = Arc::<str>::from("");
1607        let edits = ranges
1608            .into_iter()
1609            .map(|range| {
1610                let mut range = range.start.to_offset(self.snapshot.get_mut())
1611                    ..range.end.to_offset(&self.snapshot.get_mut());
1612                if range.start > range.end {
1613                    mem::swap(&mut range.start, &mut range.end);
1614                }
1615                (range, empty.clone())
1616            })
1617            .collect::<Vec<_>>();
1618
1619        return autoindent_ranges_internal(self, edits, cx);
1620
1621        fn autoindent_ranges_internal(
1622            this: &mut MultiBuffer,
1623            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1624            cx: &mut Context<MultiBuffer>,
1625        ) {
1626            let (buffer_edits, edited_excerpt_ids) =
1627                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1628
1629            let mut buffer_ids = Vec::new();
1630            for (buffer_id, mut edits) in buffer_edits {
1631                buffer_ids.push(buffer_id);
1632                edits.sort_unstable_by_key(|edit| edit.range.start);
1633
1634                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1635                for edit in edits {
1636                    if let Some(last_range) = ranges.last_mut()
1637                        && edit.range.start <= last_range.end
1638                    {
1639                        last_range.end = last_range.end.max(edit.range.end);
1640                        continue;
1641                    }
1642                    ranges.push(edit.range);
1643                }
1644
1645                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1646                    buffer.autoindent_ranges(ranges, cx);
1647                })
1648            }
1649
1650            cx.emit(Event::ExcerptsEdited {
1651                excerpt_ids: edited_excerpt_ids,
1652                buffer_ids,
1653            });
1654        }
1655    }
1656
1657    pub fn set_active_selections(
1658        &self,
1659        selections: &[Selection<Anchor>],
1660        line_mode: bool,
1661        cursor_shape: CursorShape,
1662        cx: &mut Context<Self>,
1663    ) {
1664        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1665            Default::default();
1666        let snapshot = self.read(cx);
1667        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1668        for selection in selections {
1669            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1670            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1671
1672            cursor.seek(&Some(start_locator), Bias::Left);
1673            while let Some(excerpt) = cursor.item()
1674                && excerpt.locator <= *end_locator
1675            {
1676                let mut start = excerpt.range.context.start;
1677                let mut end = excerpt.range.context.end;
1678                if excerpt.id == selection.start.excerpt_id {
1679                    start = selection.start.text_anchor;
1680                }
1681                if excerpt.id == selection.end.excerpt_id {
1682                    end = selection.end.text_anchor;
1683                }
1684                selections_by_buffer
1685                    .entry(excerpt.buffer_id)
1686                    .or_default()
1687                    .push(Selection {
1688                        id: selection.id,
1689                        start,
1690                        end,
1691                        reversed: selection.reversed,
1692                        goal: selection.goal,
1693                    });
1694
1695                cursor.next();
1696            }
1697        }
1698
1699        for (buffer_id, buffer_state) in self.buffers.iter() {
1700            if !selections_by_buffer.contains_key(buffer_id) {
1701                buffer_state
1702                    .buffer
1703                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1704            }
1705        }
1706
1707        for (buffer_id, mut selections) in selections_by_buffer {
1708            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1709                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1710                let mut selections = selections.into_iter().peekable();
1711                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1712                    let mut selection = selections.next()?;
1713                    while let Some(next_selection) = selections.peek() {
1714                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1715                            let next_selection = selections.next().unwrap();
1716                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1717                                selection.end = next_selection.end;
1718                            }
1719                        } else {
1720                            break;
1721                        }
1722                    }
1723                    Some(selection)
1724                }));
1725                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1726            });
1727        }
1728    }
1729
1730    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1731        for buffer in self.buffers.values() {
1732            buffer
1733                .buffer
1734                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1735        }
1736    }
1737
1738    pub fn push_excerpts<O>(
1739        &mut self,
1740        buffer: Entity<Buffer>,
1741        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1742        cx: &mut Context<Self>,
1743    ) -> Vec<ExcerptId>
1744    where
1745        O: text::ToOffset,
1746    {
1747        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1748    }
1749
1750    #[instrument(skip_all)]
1751    fn merge_excerpt_ranges<'a>(
1752        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1753    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1754        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1755        let mut counts: Vec<usize> = Vec::new();
1756        for range in expanded_ranges {
1757            if let Some(last_range) = merged_ranges.last_mut() {
1758                assert!(
1759                    last_range.context.start <= range.context.start,
1760                    "ranges must be sorted: {last_range:?} <= {range:?}"
1761                );
1762                if last_range.context.end >= range.context.start
1763                    || last_range.context.end.row + 1 == range.context.start.row
1764                {
1765                    last_range.context.end = range.context.end.max(last_range.context.end);
1766                    *counts.last_mut().unwrap() += 1;
1767                    continue;
1768                }
1769            }
1770            merged_ranges.push(range.clone());
1771            counts.push(1);
1772        }
1773        (merged_ranges, counts)
1774    }
1775
1776    pub fn insert_excerpts_after<O>(
1777        &mut self,
1778        prev_excerpt_id: ExcerptId,
1779        buffer: Entity<Buffer>,
1780        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1781        cx: &mut Context<Self>,
1782    ) -> Vec<ExcerptId>
1783    where
1784        O: text::ToOffset,
1785    {
1786        let mut ids = Vec::new();
1787        let mut next_excerpt_id =
1788            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1789                last_entry.id.0 + 1
1790            } else {
1791                1
1792            };
1793        self.insert_excerpts_with_ids_after(
1794            prev_excerpt_id,
1795            buffer,
1796            ranges.into_iter().map(|range| {
1797                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1798                ids.push(id);
1799                (id, range)
1800            }),
1801            cx,
1802        );
1803        ids
1804    }
1805
1806    pub fn insert_excerpts_with_ids_after<O>(
1807        &mut self,
1808        prev_excerpt_id: ExcerptId,
1809        buffer: Entity<Buffer>,
1810        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1811        cx: &mut Context<Self>,
1812    ) where
1813        O: text::ToOffset,
1814    {
1815        assert_eq!(self.history.transaction_depth(), 0);
1816        let mut ranges = ranges.into_iter().peekable();
1817        if ranges.peek().is_none() {
1818            return Default::default();
1819        }
1820
1821        self.sync_mut(cx);
1822
1823        let buffer_snapshot = buffer.read(cx).snapshot();
1824        let buffer_id = buffer_snapshot.remote_id();
1825
1826        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1827            self.buffer_changed_since_sync.replace(true);
1828            buffer.update(cx, |buffer, _| {
1829                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1830            });
1831            BufferState {
1832                last_version: RefCell::new(buffer_snapshot.version().clone()),
1833                last_non_text_state_update_count: Cell::new(
1834                    buffer_snapshot.non_text_state_update_count(),
1835                ),
1836                excerpts: Default::default(),
1837                _subscriptions: [
1838                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1839                    cx.subscribe(&buffer, Self::on_buffer_event),
1840                ],
1841                buffer: buffer.clone(),
1842            }
1843        });
1844
1845        let mut snapshot = self.snapshot.get_mut();
1846
1847        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1848        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1849        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1850        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1851        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1852
1853        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1854        new_excerpts.update_last(
1855            |excerpt| {
1856                excerpt.has_trailing_newline = true;
1857            },
1858            (),
1859        );
1860
1861        let next_locator = if let Some(excerpt) = cursor.item() {
1862            excerpt.locator.clone()
1863        } else {
1864            Locator::max()
1865        };
1866
1867        let mut excerpts = Vec::new();
1868        let buffer_snapshot = Arc::new(buffer_snapshot);
1869        while let Some((id, range)) = ranges.next() {
1870            let locator = Locator::between(&prev_locator, &next_locator);
1871            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1872                buffer_state.excerpts.insert(ix, locator.clone());
1873            }
1874            let range = ExcerptRange {
1875                context: buffer_snapshot.anchor_before(&range.context.start)
1876                    ..buffer_snapshot.anchor_after(&range.context.end),
1877                primary: buffer_snapshot.anchor_before(&range.primary.start)
1878                    ..buffer_snapshot.anchor_after(&range.primary.end),
1879            };
1880            excerpts.push((id, range.clone()));
1881            let excerpt = Excerpt::new(
1882                id,
1883                locator.clone(),
1884                buffer_id,
1885                buffer_snapshot.clone(),
1886                range,
1887                ranges.peek().is_some() || cursor.item().is_some(),
1888            );
1889            new_excerpts.push(excerpt, ());
1890            prev_locator = locator.clone();
1891
1892            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1893                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1894            }
1895            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1896        }
1897        snapshot
1898            .buffer_locators
1899            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1900
1901        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1902
1903        let suffix = cursor.suffix();
1904        let changed_trailing_excerpt = suffix.is_empty();
1905        new_excerpts.append(suffix, ());
1906        drop(cursor);
1907        snapshot.excerpts = new_excerpts;
1908        snapshot.excerpt_ids = new_excerpt_ids;
1909        if changed_trailing_excerpt {
1910            snapshot.trailing_excerpt_update_count += 1;
1911        }
1912
1913        let edits = Self::sync_diff_transforms(
1914            &mut snapshot,
1915            vec![Edit {
1916                old: edit_start..edit_start,
1917                new: edit_start..edit_end,
1918            }],
1919            DiffChangeKind::BufferEdited,
1920        );
1921        if !edits.is_empty() {
1922            self.subscriptions.publish(edits);
1923        }
1924
1925        cx.emit(Event::Edited {
1926            edited_buffer: None,
1927        });
1928        cx.emit(Event::ExcerptsAdded {
1929            buffer,
1930            predecessor: prev_excerpt_id,
1931            excerpts,
1932        });
1933        cx.notify();
1934    }
1935
1936    pub fn clear(&mut self, cx: &mut Context<Self>) {
1937        self.sync_mut(cx);
1938        let ids = self.excerpt_ids();
1939        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1940        self.excerpts_by_path.clear();
1941        self.paths_by_excerpt.clear();
1942        let MultiBufferSnapshot {
1943            excerpts,
1944            buffer_locators,
1945            diffs: _,
1946            diff_transforms: _,
1947            non_text_state_update_count: _,
1948            edit_count: _,
1949            is_dirty,
1950            has_deleted_file,
1951            has_conflict,
1952            has_inverted_diff,
1953            singleton: _,
1954            excerpt_ids: _,
1955            replaced_excerpts,
1956            trailing_excerpt_update_count,
1957            all_diff_hunks_expanded: _,
1958            show_deleted_hunks: _,
1959            use_extended_diff_range: _,
1960            show_headers: _,
1961        } = self.snapshot.get_mut();
1962        buffer_locators.clear();
1963        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1964        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1965        *excerpts = Default::default();
1966        *trailing_excerpt_update_count += 1;
1967        *is_dirty = false;
1968        *has_deleted_file = false;
1969        *has_conflict = false;
1970        *has_inverted_diff = false;
1971        replaced_excerpts.clear();
1972
1973        let edits = Self::sync_diff_transforms(
1974            self.snapshot.get_mut(),
1975            vec![Edit {
1976                old: start..prev_len,
1977                new: start..start,
1978            }],
1979            DiffChangeKind::BufferEdited,
1980        );
1981        if !edits.is_empty() {
1982            self.subscriptions.publish(edits);
1983        }
1984        cx.emit(Event::Edited {
1985            edited_buffer: None,
1986        });
1987        cx.emit(Event::ExcerptsRemoved {
1988            ids,
1989            removed_buffer_ids,
1990        });
1991        cx.notify();
1992    }
1993
1994    #[ztracing::instrument(skip_all)]
1995    pub fn excerpts_for_buffer(
1996        &self,
1997        buffer_id: BufferId,
1998        cx: &App,
1999    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2000        let mut excerpts = Vec::new();
2001        let snapshot = self.read(cx);
2002        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
2003        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
2004            for locator in &**locators {
2005                cursor.seek_forward(&Some(locator), Bias::Left);
2006                if let Some(excerpt) = cursor.item()
2007                    && excerpt.locator == *locator
2008                {
2009                    excerpts.push((excerpt.id, excerpt.range.clone()));
2010                }
2011            }
2012        }
2013
2014        excerpts
2015    }
2016
2017    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2018        let snapshot = self.read(cx);
2019        let mut excerpts = snapshot
2020            .excerpts
2021            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2022        let mut diff_transforms = snapshot
2023            .diff_transforms
2024            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2025        diff_transforms.next();
2026        let locators = snapshot
2027            .buffer_locators
2028            .get(&buffer_id)
2029            .into_iter()
2030            .flat_map(|v| &**v);
2031        let mut result = Vec::new();
2032        for locator in locators {
2033            excerpts.seek_forward(&Some(locator), Bias::Left);
2034            if let Some(excerpt) = excerpts.item()
2035                && excerpt.locator == *locator
2036            {
2037                let excerpt_start = excerpts.start().1;
2038                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2039
2040                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2041                let overshoot = excerpt_start - diff_transforms.start().0;
2042                let start = diff_transforms.start().1 + overshoot;
2043
2044                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2045                let overshoot = excerpt_end - diff_transforms.start().0;
2046                let end = diff_transforms.start().1 + overshoot;
2047
2048                result.push(start.0..end.0)
2049            }
2050        }
2051        result
2052    }
2053
2054    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2055        self.snapshot
2056            .borrow()
2057            .excerpts
2058            .iter()
2059            .map(|entry| entry.buffer_id)
2060            .collect()
2061    }
2062
2063    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2064        self.snapshot
2065            .borrow()
2066            .excerpts
2067            .iter()
2068            .map(|entry| entry.id)
2069            .collect()
2070    }
2071
2072    pub fn excerpt_containing(
2073        &self,
2074        position: impl ToOffset,
2075        cx: &App,
2076    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2077        let snapshot = self.read(cx);
2078        let offset = position.to_offset(&snapshot);
2079
2080        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2081        cursor.seek(&offset);
2082        cursor
2083            .excerpt()
2084            .or_else(|| snapshot.excerpts.last())
2085            .map(|excerpt| {
2086                (
2087                    excerpt.id,
2088                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2089                    excerpt.range.context.clone(),
2090                )
2091            })
2092    }
2093
2094    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2095        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2096            self.buffer(buffer_id)
2097        } else {
2098            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2099            Some(buffer)
2100        }
2101    }
2102
2103    // If point is at the end of the buffer, the last excerpt is returned
2104    pub fn point_to_buffer_offset<T: ToOffset>(
2105        &self,
2106        point: T,
2107        cx: &App,
2108    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2109        let snapshot = self.read(cx);
2110        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2111        Some((
2112            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2113            offset,
2114        ))
2115    }
2116
2117    // If point is at the end of the buffer, the last excerpt is returned
2118    pub fn point_to_buffer_point<T: ToPoint>(
2119        &self,
2120        point: T,
2121        cx: &App,
2122    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2123        let snapshot = self.read(cx);
2124        let (buffer, point, is_main_buffer) =
2125            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2126        Some((
2127            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2128            point,
2129            is_main_buffer,
2130        ))
2131    }
2132
2133    pub fn buffer_point_to_anchor(
2134        &self,
2135        // todo(lw): We shouldn't need this?
2136        buffer: &Entity<Buffer>,
2137        point: Point,
2138        cx: &App,
2139    ) -> Option<Anchor> {
2140        let mut found = None;
2141        let snapshot = buffer.read(cx).snapshot();
2142        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2143            let start = range.context.start.to_point(&snapshot);
2144            let end = range.context.end.to_point(&snapshot);
2145            if start <= point && point < end {
2146                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2147                break;
2148            }
2149            if point < start {
2150                found = Some((start, excerpt_id));
2151            }
2152            if point > end {
2153                found = Some((end, excerpt_id));
2154            }
2155        }
2156
2157        found.map(|(point, excerpt_id)| {
2158            let text_anchor = snapshot.anchor_after(point);
2159            Anchor::in_buffer(excerpt_id, text_anchor)
2160        })
2161    }
2162
2163    pub fn buffer_anchor_to_anchor(
2164        &self,
2165        // todo(lw): We shouldn't need this?
2166        buffer: &Entity<Buffer>,
2167        anchor: text::Anchor,
2168        cx: &App,
2169    ) -> Option<Anchor> {
2170        let snapshot = buffer.read(cx).snapshot();
2171        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2172            if range.context.start.cmp(&anchor, &snapshot).is_le()
2173                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2174            {
2175                return Some(Anchor::in_buffer(excerpt_id, anchor));
2176            }
2177        }
2178
2179        None
2180    }
2181
2182    pub fn merge_excerpts(
2183        &mut self,
2184        excerpt_ids: &[ExcerptId],
2185        cx: &mut Context<Self>,
2186    ) -> ExcerptId {
2187        debug_assert!(!excerpt_ids.is_empty());
2188        if excerpt_ids.len() == 1 {
2189            return excerpt_ids[0];
2190        }
2191
2192        let snapshot = self.snapshot(cx);
2193
2194        let first_range = snapshot
2195            .context_range_for_excerpt(excerpt_ids[0])
2196            .expect("first excerpt must exist");
2197        let last_range = snapshot
2198            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2199            .expect("last excerpt must exist");
2200
2201        let union_range = first_range.start..last_range.end;
2202
2203        drop(snapshot);
2204
2205        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2206        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2207
2208        excerpt_ids[0]
2209    }
2210
2211    pub fn remove_excerpts(
2212        &mut self,
2213        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2214        cx: &mut Context<Self>,
2215    ) {
2216        self.sync_mut(cx);
2217        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2218        if ids.is_empty() {
2219            return;
2220        }
2221        self.buffer_changed_since_sync.replace(true);
2222
2223        let mut snapshot = self.snapshot.get_mut();
2224        let mut new_excerpts = SumTree::default();
2225        let mut cursor = snapshot
2226            .excerpts
2227            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2228        let mut edits = Vec::new();
2229        let mut excerpt_ids = ids.iter().copied().peekable();
2230        let mut removed_buffer_ids = Vec::new();
2231        let mut removed_excerpts_for_buffers = HashSet::default();
2232
2233        while let Some(excerpt_id) = excerpt_ids.next() {
2234            self.paths_by_excerpt.remove(&excerpt_id);
2235            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2236            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2237            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2238
2239            if let Some(mut excerpt) = cursor.item() {
2240                if excerpt.id != excerpt_id {
2241                    continue;
2242                }
2243                let mut old_start = cursor.start().1;
2244
2245                // Skip over the removed excerpt.
2246                'remove_excerpts: loop {
2247                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2248                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2249                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2250                        if buffer_state.excerpts.is_empty() {
2251                            log::debug!(
2252                                "removing buffer and diff for buffer {}",
2253                                excerpt.buffer_id
2254                            );
2255                            self.buffers.remove(&excerpt.buffer_id);
2256                            removed_buffer_ids.push(excerpt.buffer_id);
2257                        }
2258                    }
2259                    cursor.next();
2260
2261                    // Skip over any subsequent excerpts that are also removed.
2262                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2263                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2264                        if let Some(next_excerpt) = cursor.item()
2265                            && next_excerpt.locator == *next_locator
2266                        {
2267                            excerpt_ids.next();
2268                            excerpt = next_excerpt;
2269                            continue 'remove_excerpts;
2270                        }
2271                    }
2272
2273                    break;
2274                }
2275
2276                // When removing the last excerpt, remove the trailing newline from
2277                // the previous excerpt.
2278                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2279                    old_start -= 1;
2280                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2281                }
2282
2283                // Push an edit for the removal of this run of excerpts.
2284                let old_end = cursor.start().1;
2285                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2286                edits.push(Edit {
2287                    old: old_start..old_end,
2288                    new: new_start..new_start,
2289                });
2290            }
2291        }
2292        let suffix = cursor.suffix();
2293        let changed_trailing_excerpt = suffix.is_empty();
2294        new_excerpts.append(suffix, ());
2295        drop(cursor);
2296        for buffer_id in removed_excerpts_for_buffers {
2297            match self.buffers.get(&buffer_id) {
2298                Some(buffer_state) => {
2299                    snapshot
2300                        .buffer_locators
2301                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2302                }
2303                None => {
2304                    snapshot.buffer_locators.remove(&buffer_id);
2305                }
2306            }
2307        }
2308        snapshot.excerpts = new_excerpts;
2309        for buffer_id in &removed_buffer_ids {
2310            self.diffs.remove(buffer_id);
2311            snapshot.diffs.remove(buffer_id);
2312        }
2313
2314        // Recalculate has_inverted_diff after removing diffs
2315        if !removed_buffer_ids.is_empty() {
2316            snapshot.has_inverted_diff = snapshot
2317                .diffs
2318                .iter()
2319                .any(|(_, diff)| diff.main_buffer.is_some());
2320        }
2321
2322        if changed_trailing_excerpt {
2323            snapshot.trailing_excerpt_update_count += 1;
2324        }
2325
2326        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2327        if !edits.is_empty() {
2328            self.subscriptions.publish(edits);
2329        }
2330        cx.emit(Event::Edited {
2331            edited_buffer: None,
2332        });
2333        cx.emit(Event::ExcerptsRemoved {
2334            ids,
2335            removed_buffer_ids,
2336        });
2337        cx.notify();
2338    }
2339
2340    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2341        &self,
2342        anchors: Anchors,
2343        cx: &mut Context<Self>,
2344    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2345        let mut error = None;
2346        let mut futures = Vec::new();
2347        for anchor in anchors {
2348            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2349                if let Some(buffer) = self.buffers.get(&buffer_id) {
2350                    buffer.buffer.update(cx, |buffer, _| {
2351                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2352                    });
2353                } else {
2354                    error = Some(anyhow!(
2355                        "buffer {buffer_id} is not part of this multi-buffer"
2356                    ));
2357                    break;
2358                }
2359            }
2360        }
2361        async move {
2362            if let Some(error) = error {
2363                Err(error)?;
2364            }
2365            for future in futures {
2366                future.await?;
2367            }
2368            Ok(())
2369        }
2370    }
2371
2372    pub fn text_anchor_for_position<T: ToOffset>(
2373        &self,
2374        position: T,
2375        cx: &App,
2376    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2377        let snapshot = self.read(cx);
2378        let anchor = snapshot.anchor_before(position);
2379        let buffer = self
2380            .buffers
2381            .get(&anchor.text_anchor.buffer_id?)?
2382            .buffer
2383            .clone();
2384        Some((buffer, anchor.text_anchor))
2385    }
2386
2387    fn on_buffer_event(
2388        &mut self,
2389        buffer: Entity<Buffer>,
2390        event: &language::BufferEvent,
2391        cx: &mut Context<Self>,
2392    ) {
2393        use language::BufferEvent;
2394        let buffer_id = buffer.read(cx).remote_id();
2395        cx.emit(match event {
2396            BufferEvent::Edited => Event::Edited {
2397                edited_buffer: Some(buffer),
2398            },
2399            BufferEvent::DirtyChanged => Event::DirtyChanged,
2400            BufferEvent::Saved => Event::Saved,
2401            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2402            BufferEvent::Reloaded => Event::Reloaded,
2403            BufferEvent::LanguageChanged(has_language) => {
2404                Event::LanguageChanged(buffer_id, *has_language)
2405            }
2406            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2407            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2408            BufferEvent::CapabilityChanged => {
2409                self.capability = buffer.read(cx).capability();
2410                return;
2411            }
2412            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2413        });
2414    }
2415
2416    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2417        let diff = diff.read(cx);
2418        let buffer_id = diff.buffer_id;
2419        let diff = DiffStateSnapshot {
2420            diff: diff.snapshot(cx),
2421            main_buffer: None,
2422        };
2423        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2424    }
2425
2426    fn inverted_buffer_diff_language_changed(
2427        &mut self,
2428        diff: Entity<BufferDiff>,
2429        main_buffer: Entity<language::Buffer>,
2430        cx: &mut Context<Self>,
2431    ) {
2432        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2433        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2434        let diff = diff.read(cx);
2435        let diff = DiffStateSnapshot {
2436            diff: diff.snapshot(cx),
2437            main_buffer: Some(main_buffer_snapshot),
2438        };
2439        self.snapshot
2440            .get_mut()
2441            .diffs
2442            .insert(base_text_buffer_id, diff);
2443    }
2444
2445    fn buffer_diff_changed(
2446        &mut self,
2447        diff: Entity<BufferDiff>,
2448        range: Range<text::Anchor>,
2449        cx: &mut Context<Self>,
2450    ) {
2451        self.sync_mut(cx);
2452
2453        let diff = diff.read(cx);
2454        let buffer_id = diff.buffer_id;
2455
2456        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2457            return;
2458        };
2459        let new_diff = DiffStateSnapshot {
2460            diff: diff.snapshot(cx),
2461            main_buffer: None,
2462        };
2463        let mut snapshot = self.snapshot.get_mut();
2464        let base_text_changed = snapshot
2465            .diffs
2466            .get(&buffer_id)
2467            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2468        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2469
2470        let buffer = buffer_state.buffer.read(cx);
2471        let diff_change_range = range.to_offset(buffer);
2472
2473        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2474        let edits = Self::sync_diff_transforms(
2475            &mut snapshot,
2476            excerpt_edits,
2477            DiffChangeKind::DiffUpdated {
2478                base_changed: base_text_changed,
2479            },
2480        );
2481        if !edits.is_empty() {
2482            self.subscriptions.publish(edits);
2483        }
2484        cx.emit(Event::Edited {
2485            edited_buffer: None,
2486        });
2487    }
2488
2489    fn inverted_buffer_diff_changed(
2490        &mut self,
2491        diff: Entity<BufferDiff>,
2492        main_buffer: Entity<language::Buffer>,
2493        diff_change_range: Range<usize>,
2494        cx: &mut Context<Self>,
2495    ) {
2496        self.sync_mut(cx);
2497
2498        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2499        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2500            return;
2501        };
2502
2503        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2504        let diff = diff.read(cx);
2505        let new_diff = DiffStateSnapshot {
2506            diff: diff.snapshot(cx),
2507            main_buffer: Some(main_buffer_snapshot),
2508        };
2509        let mut snapshot = self.snapshot.get_mut();
2510        snapshot
2511            .diffs
2512            .insert_or_replace(base_text_buffer_id, new_diff);
2513
2514        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2515        let edits = Self::sync_diff_transforms(
2516            &mut snapshot,
2517            excerpt_edits,
2518            DiffChangeKind::DiffUpdated {
2519                // We don't read this field for inverted diffs.
2520                base_changed: false,
2521            },
2522        );
2523        if !edits.is_empty() {
2524            self.subscriptions.publish(edits);
2525        }
2526        cx.emit(Event::Edited {
2527            edited_buffer: None,
2528        });
2529    }
2530
2531    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2532        self.buffers.values().map(|state| state.buffer.clone())
2533    }
2534
2535    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2536        self.all_buffers_iter().collect()
2537    }
2538
2539    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2540        self.buffers.keys().copied()
2541    }
2542
2543    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2544        self.all_buffer_ids_iter().collect()
2545    }
2546
2547    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2548        self.buffers
2549            .get(&buffer_id)
2550            .map(|state| state.buffer.clone())
2551    }
2552
2553    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2554        self.point_to_buffer_offset(point, cx)
2555            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2556    }
2557
2558    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2559        let buffer_id = self
2560            .snapshot
2561            .borrow()
2562            .excerpts
2563            .first()
2564            .map(|excerpt| excerpt.buffer.remote_id());
2565        buffer_id
2566            .and_then(|buffer_id| self.buffer(buffer_id))
2567            .map(|buffer| {
2568                let buffer = buffer.read(cx);
2569                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2570            })
2571            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2572    }
2573
2574    pub fn language_settings_at<'a, T: ToOffset>(
2575        &'a self,
2576        point: T,
2577        cx: &'a App,
2578    ) -> Cow<'a, LanguageSettings> {
2579        let mut language = None;
2580        let mut file = None;
2581        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2582            let buffer = buffer.read(cx);
2583            language = buffer.language_at(offset);
2584            file = buffer.file();
2585        }
2586        language_settings(language.map(|l| l.name()), file, cx)
2587    }
2588
2589    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2590        self.buffers.values().for_each(|state| f(&state.buffer))
2591    }
2592
2593    pub fn explicit_title(&self) -> Option<&str> {
2594        self.title.as_deref()
2595    }
2596
2597    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2598        if let Some(title) = self.title.as_ref() {
2599            return title.into();
2600        }
2601
2602        if let Some(buffer) = self.as_singleton() {
2603            let buffer = buffer.read(cx);
2604
2605            if let Some(file) = buffer.file() {
2606                return file.file_name(cx).into();
2607            }
2608
2609            if let Some(title) = self.buffer_content_title(buffer) {
2610                return title;
2611            }
2612        };
2613
2614        "untitled".into()
2615    }
2616
2617    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2618        let mut is_leading_whitespace = true;
2619        let mut count = 0;
2620        let mut prev_was_space = false;
2621        let mut title = String::new();
2622
2623        for ch in buffer.snapshot().chars() {
2624            if is_leading_whitespace && ch.is_whitespace() {
2625                continue;
2626            }
2627
2628            is_leading_whitespace = false;
2629
2630            if ch == '\n' || count >= 40 {
2631                break;
2632            }
2633
2634            if ch.is_whitespace() {
2635                if !prev_was_space {
2636                    title.push(' ');
2637                    count += 1;
2638                    prev_was_space = true;
2639                }
2640            } else {
2641                title.push(ch);
2642                count += 1;
2643                prev_was_space = false;
2644            }
2645        }
2646
2647        let title = title.trim_end().to_string();
2648
2649        if title.is_empty() {
2650            return None;
2651        }
2652
2653        Some(title.into())
2654    }
2655
2656    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2657        self.title = Some(title);
2658        cx.notify();
2659    }
2660
2661    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2662    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2663        for buffer_state in self.buffers.values() {
2664            buffer_state
2665                .buffer
2666                .update(cx, |buffer, _cx| buffer.refresh_preview());
2667        }
2668    }
2669
2670    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2671    pub fn preserve_preview(&self, cx: &App) -> bool {
2672        self.buffers
2673            .values()
2674            .all(|state| state.buffer.read(cx).preserve_preview())
2675    }
2676
2677    #[cfg(any(test, feature = "test-support"))]
2678    pub fn is_parsing(&self, cx: &App) -> bool {
2679        self.as_singleton().unwrap().read(cx).is_parsing()
2680    }
2681
2682    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2683        let buffer_id = diff.read(cx).buffer_id;
2684
2685        if let Some(existing_diff) = self.diff_for(buffer_id)
2686            && diff.entity_id() == existing_diff.entity_id()
2687        {
2688            return;
2689        }
2690
2691        self.buffer_diff_changed(
2692            diff.clone(),
2693            text::Anchor::min_max_range_for_buffer(buffer_id),
2694            cx,
2695        );
2696        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2697    }
2698
2699    pub fn add_inverted_diff(
2700        &mut self,
2701        diff: Entity<BufferDiff>,
2702        main_buffer: Entity<language::Buffer>,
2703        cx: &mut Context<Self>,
2704    ) {
2705        let snapshot = diff.read(cx).base_text(cx);
2706        let base_text_buffer_id = snapshot.remote_id();
2707        let diff_change_range = 0..snapshot.len();
2708        self.snapshot.get_mut().has_inverted_diff = true;
2709        self.inverted_buffer_diff_changed(diff.clone(), main_buffer.clone(), diff_change_range, cx);
2710        self.diffs.insert(
2711            base_text_buffer_id,
2712            DiffState::new_inverted(diff, main_buffer, cx),
2713        );
2714    }
2715
2716    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2717        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2718    }
2719
2720    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2721        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2722    }
2723
2724    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2725        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2726    }
2727
2728    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2729        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2730        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2731    }
2732
2733    pub fn all_diff_hunks_expanded(&self) -> bool {
2734        self.snapshot.borrow().all_diff_hunks_expanded
2735    }
2736
2737    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2738        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2739        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2740    }
2741
2742    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2743        self.snapshot.get_mut().show_deleted_hunks = show;
2744
2745        self.sync_mut(cx);
2746
2747        let old_len = self.snapshot.borrow().len();
2748
2749        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2750        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2751
2752        let new_len = self.snapshot.borrow().len();
2753
2754        self.subscriptions.publish(vec![Edit {
2755            old: MultiBufferOffset(0)..old_len,
2756            new: MultiBufferOffset(0)..new_len,
2757        }]);
2758
2759        cx.emit(Event::DiffHunksToggled);
2760        cx.emit(Event::Edited {
2761            edited_buffer: None,
2762        });
2763    }
2764
2765    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2766        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2767    }
2768
2769    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2770        self.read(cx)
2771            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2772            .nth(1)
2773            .is_some()
2774    }
2775
2776    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2777        let snapshot = self.read(cx);
2778        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2779        let offset_range = range.to_offset(&snapshot);
2780        cursor.seek(&offset_range.start, Bias::Left);
2781        while let Some(item) = cursor.item() {
2782            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2783                break;
2784            }
2785            if item.hunk_info().is_some() {
2786                return true;
2787            }
2788            cursor.next();
2789        }
2790        false
2791    }
2792
2793    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2794        let snapshot = self.read(cx);
2795        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2796        for range in ranges {
2797            let range = range.to_point(&snapshot);
2798            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2799            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2800                .min(snapshot.len());
2801            cursor.seek(&start, Bias::Right);
2802            while let Some(item) = cursor.item() {
2803                if *cursor.start() >= end {
2804                    break;
2805                }
2806                if item.hunk_info().is_some() {
2807                    return true;
2808                }
2809                cursor.next();
2810            }
2811        }
2812        false
2813    }
2814
2815    pub fn expand_or_collapse_diff_hunks_inner(
2816        &mut self,
2817        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2818        expand: bool,
2819        cx: &mut Context<Self>,
2820    ) -> Vec<Edit<MultiBufferOffset>> {
2821        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2822            return Vec::new();
2823        }
2824        self.sync_mut(cx);
2825        let mut snapshot = self.snapshot.get_mut();
2826        let mut excerpt_edits = Vec::new();
2827        let mut last_hunk_row = None;
2828        for (range, end_excerpt_id) in ranges {
2829            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2830                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2831                    continue;
2832                }
2833                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2834                    continue;
2835                }
2836                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2837                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2838                let start = snapshot.excerpt_offset_for_anchor(&start);
2839                let end = snapshot.excerpt_offset_for_anchor(&end);
2840                last_hunk_row = Some(diff_hunk.row_range.start);
2841                excerpt_edits.push(text::Edit {
2842                    old: start..end,
2843                    new: start..end,
2844                });
2845            }
2846        }
2847
2848        Self::sync_diff_transforms(
2849            &mut snapshot,
2850            excerpt_edits,
2851            DiffChangeKind::ExpandOrCollapseHunks { expand },
2852        )
2853    }
2854
2855    pub fn expand_or_collapse_diff_hunks(
2856        &mut self,
2857        ranges: Vec<Range<Anchor>>,
2858        expand: bool,
2859        cx: &mut Context<Self>,
2860    ) {
2861        let snapshot = self.snapshot.borrow().clone();
2862        let ranges = ranges.iter().map(move |range| {
2863            let end_excerpt_id = range.end.excerpt_id;
2864            let range = range.to_point(&snapshot);
2865            let mut peek_end = range.end;
2866            if range.end.row < snapshot.max_row().0 {
2867                peek_end = Point::new(range.end.row + 1, 0);
2868            };
2869            (range.start..peek_end, end_excerpt_id)
2870        });
2871        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2872        if !edits.is_empty() {
2873            self.subscriptions.publish(edits);
2874        }
2875        cx.emit(Event::DiffHunksToggled);
2876        cx.emit(Event::Edited {
2877            edited_buffer: None,
2878        });
2879    }
2880
2881    pub fn resize_excerpt(
2882        &mut self,
2883        id: ExcerptId,
2884        range: Range<text::Anchor>,
2885        cx: &mut Context<Self>,
2886    ) {
2887        self.sync_mut(cx);
2888
2889        let mut snapshot = self.snapshot.get_mut();
2890        let locator = snapshot.excerpt_locator_for_id(id);
2891        let mut new_excerpts = SumTree::default();
2892        let mut cursor = snapshot
2893            .excerpts
2894            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2895        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2896
2897        let prefix = cursor.slice(&Some(locator), Bias::Left);
2898        new_excerpts.append(prefix, ());
2899
2900        let mut excerpt = cursor.item().unwrap().clone();
2901        let old_text_len = excerpt.text_summary.len;
2902
2903        excerpt.range.context.start = range.start;
2904        excerpt.range.context.end = range.end;
2905        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2906
2907        excerpt.text_summary = excerpt
2908            .buffer
2909            .text_summary_for_range(excerpt.range.context.clone());
2910
2911        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2912        let old_start_offset = cursor.start().1;
2913        let new_text_len = excerpt.text_summary.len;
2914        let edit = Edit {
2915            old: old_start_offset..old_start_offset + old_text_len,
2916            new: new_start_offset..new_start_offset + new_text_len,
2917        };
2918
2919        if let Some(last_edit) = edits.last_mut() {
2920            if last_edit.old.end == edit.old.start {
2921                last_edit.old.end = edit.old.end;
2922                last_edit.new.end = edit.new.end;
2923            } else {
2924                edits.push(edit);
2925            }
2926        } else {
2927            edits.push(edit);
2928        }
2929
2930        new_excerpts.push(excerpt, ());
2931
2932        cursor.next();
2933
2934        new_excerpts.append(cursor.suffix(), ());
2935
2936        drop(cursor);
2937        snapshot.excerpts = new_excerpts;
2938
2939        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2940        if !edits.is_empty() {
2941            self.subscriptions.publish(edits);
2942        }
2943        cx.emit(Event::Edited {
2944            edited_buffer: None,
2945        });
2946        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2947        cx.notify();
2948    }
2949
2950    pub fn expand_excerpts(
2951        &mut self,
2952        ids: impl IntoIterator<Item = ExcerptId>,
2953        line_count: u32,
2954        direction: ExpandExcerptDirection,
2955        cx: &mut Context<Self>,
2956    ) {
2957        if line_count == 0 {
2958            return;
2959        }
2960        self.sync_mut(cx);
2961        if !self.excerpts_by_path.is_empty() {
2962            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2963            return;
2964        }
2965        let mut snapshot = self.snapshot.get_mut();
2966
2967        let ids = ids.into_iter().collect::<Vec<_>>();
2968        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2969        let mut new_excerpts = SumTree::default();
2970        let mut cursor = snapshot
2971            .excerpts
2972            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2973        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2974
2975        for locator in &locators {
2976            let prefix = cursor.slice(&Some(locator), Bias::Left);
2977            new_excerpts.append(prefix, ());
2978
2979            let mut excerpt = cursor.item().unwrap().clone();
2980            let old_text_len = excerpt.text_summary.len;
2981
2982            let up_line_count = if direction.should_expand_up() {
2983                line_count
2984            } else {
2985                0
2986            };
2987
2988            let start_row = excerpt
2989                .range
2990                .context
2991                .start
2992                .to_point(&excerpt.buffer)
2993                .row
2994                .saturating_sub(up_line_count);
2995            let start_point = Point::new(start_row, 0);
2996            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2997
2998            let down_line_count = if direction.should_expand_down() {
2999                line_count
3000            } else {
3001                0
3002            };
3003
3004            let mut end_point = excerpt.buffer.clip_point(
3005                excerpt.range.context.end.to_point(&excerpt.buffer)
3006                    + Point::new(down_line_count, 0),
3007                Bias::Left,
3008            );
3009            end_point.column = excerpt.buffer.line_len(end_point.row);
3010            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3011            excerpt.max_buffer_row = end_point.row;
3012
3013            excerpt.text_summary = excerpt
3014                .buffer
3015                .text_summary_for_range(excerpt.range.context.clone());
3016
3017            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3018            let old_start_offset = cursor.start().1;
3019            let new_text_len = excerpt.text_summary.len;
3020            let edit = Edit {
3021                old: old_start_offset..old_start_offset + old_text_len,
3022                new: new_start_offset..new_start_offset + new_text_len,
3023            };
3024
3025            if let Some(last_edit) = edits.last_mut() {
3026                if last_edit.old.end == edit.old.start {
3027                    last_edit.old.end = edit.old.end;
3028                    last_edit.new.end = edit.new.end;
3029                } else {
3030                    edits.push(edit);
3031                }
3032            } else {
3033                edits.push(edit);
3034            }
3035
3036            new_excerpts.push(excerpt, ());
3037
3038            cursor.next();
3039        }
3040
3041        new_excerpts.append(cursor.suffix(), ());
3042
3043        drop(cursor);
3044        snapshot.excerpts = new_excerpts;
3045
3046        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3047        if !edits.is_empty() {
3048            self.subscriptions.publish(edits);
3049        }
3050        cx.emit(Event::Edited {
3051            edited_buffer: None,
3052        });
3053        cx.emit(Event::ExcerptsExpanded { ids });
3054        cx.notify();
3055    }
3056
3057    #[ztracing::instrument(skip_all)]
3058    fn sync(&self, cx: &App) {
3059        let changed = self.buffer_changed_since_sync.replace(false);
3060        if !changed {
3061            return;
3062        }
3063        let edits = Self::sync_from_buffer_changes(
3064            &mut self.snapshot.borrow_mut(),
3065            &self.buffers,
3066            &self.diffs,
3067            cx,
3068        );
3069        if !edits.is_empty() {
3070            self.subscriptions.publish(edits);
3071        }
3072    }
3073
3074    fn sync_mut(&mut self, cx: &App) {
3075        let changed = self.buffer_changed_since_sync.replace(false);
3076        if !changed {
3077            return;
3078        }
3079        let edits =
3080            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3081
3082        if !edits.is_empty() {
3083            self.subscriptions.publish(edits);
3084        }
3085    }
3086
3087    fn sync_from_buffer_changes(
3088        snapshot: &mut MultiBufferSnapshot,
3089        buffers: &BTreeMap<BufferId, BufferState>,
3090        diffs: &HashMap<BufferId, DiffState>,
3091        cx: &App,
3092    ) -> Vec<Edit<MultiBufferOffset>> {
3093        let MultiBufferSnapshot {
3094            excerpts,
3095            buffer_locators: _,
3096            diffs: buffer_diff,
3097            diff_transforms: _,
3098            non_text_state_update_count,
3099            edit_count,
3100            is_dirty,
3101            has_deleted_file,
3102            has_conflict,
3103            has_inverted_diff: _,
3104            singleton: _,
3105            excerpt_ids: _,
3106            replaced_excerpts: _,
3107            trailing_excerpt_update_count: _,
3108            all_diff_hunks_expanded: _,
3109            show_deleted_hunks: _,
3110            use_extended_diff_range: _,
3111            show_headers: _,
3112        } = snapshot;
3113        *is_dirty = false;
3114        *has_deleted_file = false;
3115        *has_conflict = false;
3116
3117        if !diffs.is_empty() {
3118            let mut diffs_to_add = Vec::new();
3119            for (id, diff) in diffs {
3120                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3121                // and use the diff hunk base text ranges to compute diff transforms.
3122                // Those base text ranges are usize, so make sure if the base text changed
3123                // we also update the diff snapshot so that we don't use stale offsets
3124                if buffer_diff.get(id).is_none_or(|existing_diff| {
3125                    if existing_diff.main_buffer.is_none() {
3126                        return false;
3127                    }
3128                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3129                    base_text.remote_id() != existing_diff.base_text().remote_id()
3130                        || base_text
3131                            .version()
3132                            .changed_since(existing_diff.base_text().version())
3133                }) {
3134                    if diffs_to_add.capacity() == 0 {
3135                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3136                        // meaning re-allocations will be fairly expensive
3137                        diffs_to_add.reserve(diffs.len());
3138                    }
3139                    diffs_to_add.push((*id, diff.snapshot(cx)));
3140                }
3141            }
3142            buffer_diff.extend(diffs_to_add);
3143        }
3144
3145        let mut excerpts_to_edit = Vec::new();
3146        let mut non_text_state_updated = false;
3147        let mut edited = false;
3148        for buffer_state in buffers.values() {
3149            let buffer = buffer_state.buffer.read(cx);
3150            let version = buffer.version();
3151            let non_text_state_update_count = buffer.non_text_state_update_count();
3152
3153            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3154            let buffer_non_text_state_updated =
3155                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3156            if buffer_edited || buffer_non_text_state_updated {
3157                *buffer_state.last_version.borrow_mut() = version;
3158                buffer_state
3159                    .last_non_text_state_update_count
3160                    .set(non_text_state_update_count);
3161                excerpts_to_edit.extend(
3162                    buffer_state
3163                        .excerpts
3164                        .iter()
3165                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3166                );
3167            }
3168
3169            edited |= buffer_edited;
3170            non_text_state_updated |= buffer_non_text_state_updated;
3171            *is_dirty |= buffer.is_dirty();
3172            *has_deleted_file |= buffer
3173                .file()
3174                .is_some_and(|file| file.disk_state().is_deleted());
3175            *has_conflict |= buffer.has_conflict();
3176        }
3177        if edited {
3178            *edit_count += 1;
3179        }
3180        if non_text_state_updated {
3181            *non_text_state_update_count += 1;
3182        }
3183
3184        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3185
3186        let mut edits = Vec::new();
3187        let mut new_excerpts = SumTree::default();
3188        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3189
3190        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3191            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3192            let old_excerpt = cursor.item().unwrap();
3193            let buffer = buffer.read(cx);
3194            let buffer_id = buffer.remote_id();
3195            let mut new_excerpt;
3196            if buffer_edited {
3197                edits.extend(
3198                    buffer
3199                        .edits_since_in_range::<usize>(
3200                            old_excerpt.buffer.version(),
3201                            old_excerpt.range.context.clone(),
3202                        )
3203                        .map(|edit| {
3204                            let excerpt_old_start = cursor.start().1;
3205                            let excerpt_new_start =
3206                                ExcerptDimension(new_excerpts.summary().text.len);
3207                            let old_start = excerpt_old_start + edit.old.start;
3208                            let old_end = excerpt_old_start + edit.old.end;
3209                            let new_start = excerpt_new_start + edit.new.start;
3210                            let new_end = excerpt_new_start + edit.new.end;
3211                            Edit {
3212                                old: old_start..old_end,
3213                                new: new_start..new_end,
3214                            }
3215                        }),
3216                );
3217
3218                new_excerpt = Excerpt::new(
3219                    old_excerpt.id,
3220                    locator.clone(),
3221                    buffer_id,
3222                    Arc::new(buffer.snapshot()),
3223                    old_excerpt.range.clone(),
3224                    old_excerpt.has_trailing_newline,
3225                );
3226            } else {
3227                new_excerpt = old_excerpt.clone();
3228                new_excerpt.buffer = Arc::new(buffer.snapshot());
3229            }
3230
3231            new_excerpts.push(new_excerpt, ());
3232            cursor.next();
3233        }
3234        new_excerpts.append(cursor.suffix(), ());
3235
3236        drop(cursor);
3237        *excerpts = new_excerpts;
3238
3239        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3240    }
3241
3242    fn sync_diff_transforms(
3243        snapshot: &mut MultiBufferSnapshot,
3244        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3245        change_kind: DiffChangeKind,
3246    ) -> Vec<Edit<MultiBufferOffset>> {
3247        if excerpt_edits.is_empty() {
3248            return vec![];
3249        }
3250
3251        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3252        let mut old_diff_transforms = snapshot
3253            .diff_transforms
3254            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3255        let mut new_diff_transforms = SumTree::default();
3256        let mut old_expanded_hunks = HashSet::default();
3257        let mut output_edits = Vec::new();
3258        let mut output_delta = 0_isize;
3259        let mut at_transform_boundary = true;
3260        let mut end_of_current_insert = None;
3261
3262        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3263        while let Some(edit) = excerpt_edits.next() {
3264            excerpts.seek_forward(&edit.new.start, Bias::Right);
3265            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3266                excerpts.prev();
3267            }
3268
3269            // Keep any transforms that are before the edit.
3270            if at_transform_boundary {
3271                at_transform_boundary = false;
3272                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3273                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3274                if let Some(transform) = old_diff_transforms.item()
3275                    && old_diff_transforms.end().0 == edit.old.start
3276                    && old_diff_transforms.start().0 < edit.old.start
3277                {
3278                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3279                    old_diff_transforms.next();
3280                }
3281            }
3282
3283            // Compute the start of the edit in output coordinates.
3284            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3285            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3286            let edit_new_start =
3287                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3288
3289            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3290                &edit,
3291                &mut excerpts,
3292                &mut old_diff_transforms,
3293                &mut new_diff_transforms,
3294                &mut end_of_current_insert,
3295                &mut old_expanded_hunks,
3296                snapshot,
3297                change_kind,
3298            );
3299
3300            // Compute the end of the edit in output coordinates.
3301            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3302            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3303            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3304            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3305            let output_edit = Edit {
3306                old: edit_old_start..edit_old_end,
3307                new: edit_new_start..edit_new_end,
3308            };
3309
3310            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3311            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3312            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3313                output_edits.push(output_edit);
3314            }
3315
3316            // If this is the last edit that intersects the current diff transform,
3317            // then recreate the content up to the end of this transform, to prepare
3318            // for reusing additional slices of the old transforms.
3319            if excerpt_edits
3320                .peek()
3321                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3322            {
3323                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3324                    && match old_diff_transforms.item() {
3325                        Some(DiffTransform::BufferContent {
3326                            inserted_hunk_info: Some(hunk),
3327                            ..
3328                        }) => excerpts.item().is_some_and(|excerpt| {
3329                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3330                                && diff.main_buffer.is_some()
3331                            {
3332                                return true;
3333                            }
3334                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3335                        }),
3336                        _ => true,
3337                    };
3338
3339                let mut excerpt_offset = edit.new.end;
3340                if !keep_next_old_transform {
3341                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3342                    old_diff_transforms.next();
3343                }
3344
3345                old_expanded_hunks.clear();
3346                Self::push_buffer_content_transform(
3347                    snapshot,
3348                    &mut new_diff_transforms,
3349                    excerpt_offset,
3350                    end_of_current_insert,
3351                );
3352                at_transform_boundary = true;
3353            }
3354        }
3355
3356        // Keep any transforms that are after the last edit.
3357        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3358
3359        // Ensure there's always at least one buffer content transform.
3360        if new_diff_transforms.is_empty() {
3361            new_diff_transforms.push(
3362                DiffTransform::BufferContent {
3363                    summary: Default::default(),
3364                    inserted_hunk_info: None,
3365                },
3366                (),
3367            );
3368        }
3369
3370        drop(old_diff_transforms);
3371        drop(excerpts);
3372        snapshot.diff_transforms = new_diff_transforms;
3373        snapshot.edit_count += 1;
3374
3375        #[cfg(any(test, feature = "test-support"))]
3376        snapshot.check_invariants();
3377        output_edits
3378    }
3379
3380    fn recompute_diff_transforms_for_edit(
3381        edit: &Edit<ExcerptOffset>,
3382        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3383        old_diff_transforms: &mut Cursor<
3384            DiffTransform,
3385            Dimensions<ExcerptOffset, MultiBufferOffset>,
3386        >,
3387        new_diff_transforms: &mut SumTree<DiffTransform>,
3388        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3389        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3390        snapshot: &MultiBufferSnapshot,
3391        change_kind: DiffChangeKind,
3392    ) -> bool {
3393        log::trace!(
3394            "recomputing diff transform for edit {:?} => {:?}",
3395            edit.old.start..edit.old.end,
3396            edit.new.start..edit.new.end
3397        );
3398
3399        // Record which hunks were previously expanded.
3400        while let Some(item) = old_diff_transforms.item() {
3401            if let Some(hunk_info) = item.hunk_info() {
3402                log::trace!(
3403                    "previously expanded hunk at {:?}",
3404                    old_diff_transforms.start()
3405                );
3406                old_expanded_hunks.insert(hunk_info);
3407            }
3408            if old_diff_transforms.end().0 > edit.old.end {
3409                break;
3410            }
3411            old_diff_transforms.next();
3412        }
3413
3414        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3415        // For inverted diffs, hunks are always shown, so we can't skip this.
3416        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3417        if old_expanded_hunks.is_empty()
3418            && change_kind == DiffChangeKind::BufferEdited
3419            && !all_diff_hunks_expanded
3420            && !snapshot.has_inverted_diff
3421        {
3422            return false;
3423        }
3424
3425        // Visit each excerpt that intersects the edit.
3426        let mut did_expand_hunks = false;
3427        while let Some(excerpt) = excerpts.item() {
3428            // Recompute the expanded hunks in the portion of the excerpt that
3429            // intersects the edit.
3430            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3431                let buffer = &excerpt.buffer;
3432                let excerpt_start = *excerpts.start();
3433                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3434                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3435                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3436                let edit_buffer_start =
3437                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3438                let edit_buffer_end =
3439                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3440                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3441
3442                if let Some(main_buffer) = &diff.main_buffer {
3443                    for hunk in diff.hunks_intersecting_base_text_range(
3444                        edit_buffer_start..edit_buffer_end,
3445                        main_buffer,
3446                    ) {
3447                        did_expand_hunks = true;
3448                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3449                        if hunk_buffer_range.start < excerpt_buffer_start {
3450                            log::trace!("skipping hunk that starts before excerpt");
3451                            continue;
3452                        }
3453                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3454                        let hunk_excerpt_start = excerpt_start
3455                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3456                        let hunk_excerpt_end = excerpt_end
3457                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3458                        Self::push_buffer_content_transform(
3459                            snapshot,
3460                            new_diff_transforms,
3461                            hunk_excerpt_start,
3462                            *end_of_current_insert,
3463                        );
3464                        if !hunk_buffer_range.is_empty() {
3465                            let hunk_info = DiffTransformHunkInfo {
3466                                excerpt_id: excerpt.id,
3467                                hunk_start_anchor: hunk.buffer_range.start,
3468                                hunk_secondary_status: hunk.secondary_status,
3469                                is_logically_deleted: true,
3470                            };
3471                            *end_of_current_insert =
3472                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3473                        }
3474                    }
3475                } else {
3476                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3477                        ..buffer.anchor_after(edit_buffer_end);
3478                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3479                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3480                            continue;
3481                        }
3482
3483                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3484                        if hunk_buffer_range.start < excerpt_buffer_start {
3485                            log::trace!("skipping hunk that starts before excerpt");
3486                            continue;
3487                        }
3488
3489                        let hunk_info = DiffTransformHunkInfo {
3490                            excerpt_id: excerpt.id,
3491                            hunk_start_anchor: hunk.buffer_range.start,
3492                            hunk_secondary_status: hunk.secondary_status,
3493                            is_logically_deleted: false,
3494                        };
3495
3496                        let hunk_excerpt_start = excerpt_start
3497                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3498                        let hunk_excerpt_end = excerpt_end
3499                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3500
3501                        Self::push_buffer_content_transform(
3502                            snapshot,
3503                            new_diff_transforms,
3504                            hunk_excerpt_start,
3505                            *end_of_current_insert,
3506                        );
3507
3508                        // For every existing hunk, determine if it was previously expanded
3509                        // and if it should currently be expanded.
3510                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3511                        let should_expand_hunk = match &change_kind {
3512                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3513                                was_previously_expanded || all_diff_hunks_expanded
3514                            }
3515                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3516                                let intersects = hunk_buffer_range.is_empty()
3517                                    || hunk_buffer_range.end > edit_buffer_start;
3518                                if *expand {
3519                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3520                                } else {
3521                                    !intersects
3522                                        && (was_previously_expanded || all_diff_hunks_expanded)
3523                                }
3524                            }
3525                            _ => was_previously_expanded || all_diff_hunks_expanded,
3526                        };
3527
3528                        if should_expand_hunk {
3529                            did_expand_hunks = true;
3530                            log::trace!(
3531                                "expanding hunk {:?}, excerpt:{:?}",
3532                                hunk_excerpt_start..hunk_excerpt_end,
3533                                excerpt.id
3534                            );
3535
3536                            if !hunk.diff_base_byte_range.is_empty()
3537                                && hunk_buffer_range.start >= edit_buffer_start
3538                                && hunk_buffer_range.start <= excerpt_buffer_end
3539                                && snapshot.show_deleted_hunks
3540                            {
3541                                let base_text = diff.base_text();
3542                                let mut text_cursor =
3543                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3544                                let mut base_text_summary = text_cursor
3545                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3546
3547                                let mut has_trailing_newline = false;
3548                                if base_text_summary.last_line_chars > 0 {
3549                                    base_text_summary += TextSummary::newline();
3550                                    has_trailing_newline = true;
3551                                }
3552
3553                                new_diff_transforms.push(
3554                                    DiffTransform::DeletedHunk {
3555                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3556                                        summary: base_text_summary,
3557                                        buffer_id: excerpt.buffer_id,
3558                                        hunk_info,
3559                                        has_trailing_newline,
3560                                    },
3561                                    (),
3562                                );
3563                            }
3564
3565                            if !hunk_buffer_range.is_empty() {
3566                                *end_of_current_insert =
3567                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3568                            }
3569                        }
3570                    }
3571                }
3572            }
3573
3574            if excerpts.end() <= edit.new.end {
3575                excerpts.next();
3576            } else {
3577                break;
3578            }
3579        }
3580
3581        did_expand_hunks || !old_expanded_hunks.is_empty()
3582    }
3583
3584    fn append_diff_transforms(
3585        new_transforms: &mut SumTree<DiffTransform>,
3586        subtree: SumTree<DiffTransform>,
3587    ) {
3588        if let Some(DiffTransform::BufferContent {
3589            inserted_hunk_info,
3590            summary,
3591        }) = subtree.first()
3592            && Self::extend_last_buffer_content_transform(
3593                new_transforms,
3594                *inserted_hunk_info,
3595                *summary,
3596            )
3597        {
3598            let mut cursor = subtree.cursor::<()>(());
3599            cursor.next();
3600            cursor.next();
3601            new_transforms.append(cursor.suffix(), ());
3602            return;
3603        }
3604        new_transforms.append(subtree, ());
3605    }
3606
3607    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3608        if let DiffTransform::BufferContent {
3609            inserted_hunk_info: inserted_hunk_anchor,
3610            summary,
3611        } = transform
3612            && Self::extend_last_buffer_content_transform(
3613                new_transforms,
3614                inserted_hunk_anchor,
3615                summary,
3616            )
3617        {
3618            return;
3619        }
3620        new_transforms.push(transform, ());
3621    }
3622
3623    fn push_buffer_content_transform(
3624        old_snapshot: &MultiBufferSnapshot,
3625        new_transforms: &mut SumTree<DiffTransform>,
3626        end_offset: ExcerptOffset,
3627        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3628    ) {
3629        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3630            (end_offset.min(insertion_end_offset), Some(hunk_info))
3631        });
3632        let unchanged_region = [(end_offset, None)];
3633
3634        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3635        {
3636            let start_offset = new_transforms.summary().excerpt_len();
3637            if end_offset <= start_offset {
3638                continue;
3639            }
3640            let summary_to_add = old_snapshot
3641                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3642
3643            if !Self::extend_last_buffer_content_transform(
3644                new_transforms,
3645                inserted_hunk_info,
3646                summary_to_add,
3647            ) {
3648                new_transforms.push(
3649                    DiffTransform::BufferContent {
3650                        summary: summary_to_add,
3651                        inserted_hunk_info,
3652                    },
3653                    (),
3654                )
3655            }
3656        }
3657    }
3658
3659    fn extend_last_buffer_content_transform(
3660        new_transforms: &mut SumTree<DiffTransform>,
3661        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3662        summary_to_add: MBTextSummary,
3663    ) -> bool {
3664        let mut did_extend = false;
3665        new_transforms.update_last(
3666            |last_transform| {
3667                if let DiffTransform::BufferContent {
3668                    summary,
3669                    inserted_hunk_info: inserted_hunk_anchor,
3670                } = last_transform
3671                    && *inserted_hunk_anchor == new_inserted_hunk_info
3672                {
3673                    *summary += summary_to_add;
3674                    did_extend = true;
3675                }
3676            },
3677            (),
3678        );
3679        did_extend
3680    }
3681
3682    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3683        let snapshot = self.snapshot(cx);
3684        let excerpt_id = range.end.excerpt_id;
3685        let point_range = range.to_point(&snapshot);
3686        let expand = !self.single_hunk_is_expanded(range, cx);
3687        let edits =
3688            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3689        if !edits.is_empty() {
3690            self.subscriptions.publish(edits);
3691        }
3692        cx.emit(Event::DiffHunksToggled);
3693        cx.emit(Event::Edited {
3694            edited_buffer: None,
3695        });
3696    }
3697}
3698
3699fn build_excerpt_ranges(
3700    ranges: impl IntoIterator<Item = Range<Point>>,
3701    context_line_count: u32,
3702    buffer_snapshot: &BufferSnapshot,
3703) -> Vec<ExcerptRange<Point>> {
3704    ranges
3705        .into_iter()
3706        .map(|range| {
3707            let start_row = range.start.row.saturating_sub(context_line_count);
3708            let start = Point::new(start_row, 0);
3709            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3710            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3711            ExcerptRange {
3712                context: start..end,
3713                primary: range,
3714            }
3715        })
3716        .collect()
3717}
3718
3719#[cfg(any(test, feature = "test-support"))]
3720impl MultiBuffer {
3721    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3722        let buffer = cx.new(|cx| Buffer::local(text, cx));
3723        cx.new(|cx| Self::singleton(buffer, cx))
3724    }
3725
3726    pub fn build_multi<const COUNT: usize>(
3727        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3728        cx: &mut gpui::App,
3729    ) -> Entity<Self> {
3730        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3731        for (text, ranges) in excerpts {
3732            let buffer = cx.new(|cx| Buffer::local(text, cx));
3733            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3734            multi.update(cx, |multi, cx| {
3735                multi.push_excerpts(buffer, excerpt_ranges, cx)
3736            });
3737        }
3738
3739        multi
3740    }
3741
3742    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3743        cx.new(|cx| Self::singleton(buffer, cx))
3744    }
3745
3746    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3747        cx.new(|cx| {
3748            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3749            let mutation_count = rng.random_range(1..=5);
3750            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3751            multibuffer
3752        })
3753    }
3754
3755    pub fn randomly_edit(
3756        &mut self,
3757        rng: &mut impl rand::Rng,
3758        edit_count: usize,
3759        cx: &mut Context<Self>,
3760    ) {
3761        use util::RandomCharIter;
3762
3763        let snapshot = self.read(cx);
3764        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3765        let mut last_end = None;
3766        for _ in 0..edit_count {
3767            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3768                break;
3769            }
3770
3771            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3772            let end =
3773                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3774            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3775            last_end = Some(end);
3776
3777            let mut range = start..end;
3778            if rng.random_bool(0.2) {
3779                mem::swap(&mut range.start, &mut range.end);
3780            }
3781
3782            let new_text_len = rng.random_range(0..10);
3783            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3784
3785            edits.push((range, new_text.into()));
3786        }
3787        log::info!("mutating multi-buffer with {:?}", edits);
3788        drop(snapshot);
3789
3790        self.edit(edits, None, cx);
3791    }
3792
3793    pub fn randomly_edit_excerpts(
3794        &mut self,
3795        rng: &mut impl rand::Rng,
3796        mutation_count: usize,
3797        cx: &mut Context<Self>,
3798    ) {
3799        use rand::prelude::*;
3800        use std::env;
3801        use util::RandomCharIter;
3802
3803        let max_excerpts = env::var("MAX_EXCERPTS")
3804            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3805            .unwrap_or(5);
3806
3807        let mut buffers = Vec::new();
3808        for _ in 0..mutation_count {
3809            if rng.random_bool(0.05) {
3810                log::info!("Clearing multi-buffer");
3811                self.clear(cx);
3812                continue;
3813            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3814                let ids = self.excerpt_ids();
3815                let mut excerpts = HashSet::default();
3816                for _ in 0..rng.random_range(0..ids.len()) {
3817                    excerpts.extend(ids.choose(rng).copied());
3818                }
3819
3820                let line_count = rng.random_range(0..5);
3821
3822                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3823
3824                self.expand_excerpts(
3825                    excerpts.iter().cloned(),
3826                    line_count,
3827                    ExpandExcerptDirection::UpAndDown,
3828                    cx,
3829                );
3830                continue;
3831            }
3832
3833            let excerpt_ids = self.excerpt_ids();
3834            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3835                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3836                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3837                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3838                    let buffer = buffers.last().unwrap().read(cx);
3839                    log::info!(
3840                        "Creating new buffer {} with text: {:?}",
3841                        buffer.remote_id(),
3842                        buffer.text()
3843                    );
3844                    buffers.last().unwrap().clone()
3845                } else {
3846                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3847                };
3848
3849                let buffer = buffer_handle.read(cx);
3850                let buffer_text = buffer.text();
3851                let ranges = (0..rng.random_range(0..5))
3852                    .map(|_| {
3853                        let end_ix =
3854                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3855                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3856                        ExcerptRange::new(start_ix..end_ix)
3857                    })
3858                    .collect::<Vec<_>>();
3859                log::info!(
3860                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3861                    buffer_handle.read(cx).remote_id(),
3862                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3863                    ranges
3864                        .iter()
3865                        .map(|r| &buffer_text[r.context.clone()])
3866                        .collect::<Vec<_>>()
3867                );
3868
3869                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3870                log::info!("Inserted with ids: {:?}", excerpt_id);
3871            } else {
3872                let remove_count = rng.random_range(1..=excerpt_ids.len());
3873                let mut excerpts_to_remove = excerpt_ids
3874                    .choose_multiple(rng, remove_count)
3875                    .cloned()
3876                    .collect::<Vec<_>>();
3877                let snapshot = self.snapshot.borrow();
3878                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3879                drop(snapshot);
3880                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3881                self.remove_excerpts(excerpts_to_remove, cx);
3882            }
3883        }
3884    }
3885
3886    pub fn randomly_mutate(
3887        &mut self,
3888        rng: &mut impl rand::Rng,
3889        mutation_count: usize,
3890        cx: &mut Context<Self>,
3891    ) {
3892        use rand::prelude::*;
3893
3894        if rng.random_bool(0.7) || self.singleton {
3895            let buffer = self
3896                .buffers
3897                .values()
3898                .choose(rng)
3899                .map(|state| state.buffer.clone());
3900
3901            if let Some(buffer) = buffer {
3902                buffer.update(cx, |buffer, cx| {
3903                    if rng.random() {
3904                        buffer.randomly_edit(rng, mutation_count, cx);
3905                    } else {
3906                        buffer.randomly_undo_redo(rng, cx);
3907                    }
3908                });
3909            } else {
3910                self.randomly_edit(rng, mutation_count, cx);
3911            }
3912        } else {
3913            self.randomly_edit_excerpts(rng, mutation_count, cx);
3914        }
3915
3916        self.check_invariants(cx);
3917    }
3918
3919    fn check_invariants(&self, cx: &App) {
3920        self.read(cx).check_invariants();
3921    }
3922}
3923
3924impl EventEmitter<Event> for MultiBuffer {}
3925
3926impl MultiBufferSnapshot {
3927    pub fn text(&self) -> String {
3928        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3929            .map(|chunk| chunk.text)
3930            .collect()
3931    }
3932
3933    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3934        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3935            .flat_map(|c| c.chars().rev())
3936    }
3937
3938    fn reversed_chunks_in_range(
3939        &self,
3940        range: Range<MultiBufferOffset>,
3941    ) -> ReversedMultiBufferChunks<'_> {
3942        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3943        cursor.seek(&range.end);
3944        let current_chunks = cursor.region().as_ref().map(|region| {
3945            let start_overshoot = range.start.saturating_sub(region.range.start);
3946            let end_overshoot = range.end - region.range.start;
3947            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3948            let start = region.buffer_range.start + start_overshoot;
3949            region.buffer.reversed_chunks_in_range(start..end)
3950        });
3951        ReversedMultiBufferChunks {
3952            cursor,
3953            current_chunks,
3954            start: range.start,
3955            offset: range.end,
3956        }
3957    }
3958
3959    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3960        let offset = position.to_offset(self);
3961        self.text_for_range(offset..self.len())
3962            .flat_map(|chunk| chunk.chars())
3963    }
3964
3965    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3966        self.chunks(range, false).map(|chunk| chunk.text)
3967    }
3968
3969    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3970        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3971            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3972    }
3973
3974    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3975    where
3976        T: ToOffset,
3977    {
3978        let position = position.to_offset(self);
3979        position == self.clip_offset(position, Bias::Left)
3980            && self
3981                .bytes_in_range(position..self.len())
3982                .flatten()
3983                .copied()
3984                .take(needle.len())
3985                .eq(needle.bytes())
3986    }
3987
3988    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3989        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3990    }
3991
3992    pub fn diff_hunks_in_range<T: ToPoint>(
3993        &self,
3994        range: Range<T>,
3995    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3996        let query_range = range.start.to_point(self)..range.end.to_point(self);
3997        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3998            let diff = self.diffs.get(&buffer.remote_id())?;
3999            let iter = if let Some(main_buffer) = &diff.main_buffer {
4000                let buffer_start = buffer.point_to_offset(buffer_range.start);
4001                let buffer_end = buffer.point_to_offset(buffer_range.end);
4002                itertools::Either::Left(
4003                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4004                        .map(move |hunk| (hunk, buffer, true)),
4005                )
4006            } else {
4007                let buffer_start = buffer.anchor_before(buffer_range.start);
4008                let buffer_end = buffer.anchor_after(buffer_range.end);
4009                itertools::Either::Right(
4010                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4011                        .map(move |hunk| (hunk, buffer, false)),
4012                )
4013            };
4014            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4015                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4016                    return None;
4017                }
4018                let range = if is_inverted {
4019                    hunk.diff_base_byte_range.to_point(&buffer)
4020                } else {
4021                    hunk.range.clone()
4022                };
4023                Some((range, (hunk, is_inverted)))
4024            }))
4025        })
4026        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4027            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4028            {
4029                return None;
4030            }
4031            let end_row = if range.end.column == 0 {
4032                range.end.row
4033            } else {
4034                range.end.row + 1
4035            };
4036
4037            let word_diffs =
4038                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4039                    .then(|| {
4040                        let mut word_diffs = Vec::new();
4041
4042                        if self.show_deleted_hunks || is_inverted {
4043                            let hunk_start_offset = if is_inverted {
4044                                Anchor::in_buffer(
4045                                    excerpt.id,
4046                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4047                                )
4048                                .to_offset(self)
4049                            } else {
4050                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4051                                    .to_offset(self)
4052                            };
4053
4054                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4055                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4056                            }));
4057                        }
4058
4059                        if !is_inverted {
4060                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4061                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4062                            }));
4063                        }
4064                        word_diffs
4065                    })
4066                    .unwrap_or_default();
4067
4068            let buffer_range = if is_inverted {
4069                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4070                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4071            } else {
4072                hunk.buffer_range.clone()
4073            };
4074            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4075                DiffHunkStatusKind::Deleted
4076            } else if hunk.diff_base_byte_range.is_empty() {
4077                DiffHunkStatusKind::Added
4078            } else {
4079                DiffHunkStatusKind::Modified
4080            };
4081            Some(MultiBufferDiffHunk {
4082                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4083                buffer_id: excerpt.buffer_id,
4084                excerpt_id: excerpt.id,
4085                buffer_range,
4086                word_diffs,
4087                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4088                    ..BufferOffset(hunk.diff_base_byte_range.end),
4089                status: DiffHunkStatus {
4090                    kind: status_kind,
4091                    secondary: hunk.secondary_status,
4092                },
4093            })
4094        })
4095    }
4096
4097    fn excerpts_for_range<T: ToOffset>(
4098        &self,
4099        range: Range<T>,
4100    ) -> impl Iterator<Item = &Excerpt> + '_ {
4101        let range = range.start.to_offset(self)..range.end.to_offset(self);
4102        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4103        cursor.seek(&range.start);
4104        std::iter::from_fn(move || {
4105            let region = cursor.region()?;
4106            if region.range.start > range.end
4107                || region.range.start == range.end && region.range.start > range.start
4108            {
4109                return None;
4110            }
4111            let excerpt = region.excerpt;
4112            cursor.next_excerpt_forwards();
4113            Some(excerpt)
4114        })
4115    }
4116
4117    pub fn excerpt_ids_for_range<T: ToOffset>(
4118        &self,
4119        range: Range<T>,
4120    ) -> impl Iterator<Item = ExcerptId> + '_ {
4121        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4122    }
4123
4124    pub fn buffer_ids_for_range<T: ToOffset>(
4125        &self,
4126        range: Range<T>,
4127    ) -> impl Iterator<Item = BufferId> + '_ {
4128        self.excerpts_for_range(range)
4129            .map(|excerpt| excerpt.buffer_id)
4130    }
4131
4132    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4133    ///
4134    /// The passed in anchors must be ordered.
4135    pub fn text_anchors_to_visible_anchors(
4136        &self,
4137        anchors: impl IntoIterator<Item = text::Anchor>,
4138    ) -> Vec<Option<Anchor>> {
4139        let anchors = anchors.into_iter();
4140        let mut result = Vec::with_capacity(anchors.size_hint().0);
4141        let mut anchors = anchors.peekable();
4142        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4143        'anchors: while let Some(anchor) = anchors.peek() {
4144            let Some(buffer_id) = anchor.buffer_id else {
4145                anchors.next();
4146                result.push(None);
4147                continue 'anchors;
4148            };
4149            let mut same_buffer_anchors =
4150                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4151
4152            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4153                let Some(mut next) = same_buffer_anchors.next() else {
4154                    continue 'anchors;
4155                };
4156                'excerpts: for locator in locators.iter() {
4157                    if cursor.seek_forward(&Some(locator), Bias::Left)
4158                        && let Some(excerpt) = cursor.item()
4159                    {
4160                        loop {
4161                            // anchor is before the first excerpt
4162                            if excerpt
4163                                .range
4164                                .context
4165                                .start
4166                                .cmp(&next, &excerpt.buffer)
4167                                .is_gt()
4168                            {
4169                                // so we skip it and try the next anchor
4170                                result.push(None);
4171                                match same_buffer_anchors.next() {
4172                                    Some(anchor) => next = anchor,
4173                                    None => continue 'anchors,
4174                                }
4175                            // anchor is within the excerpt
4176                            } else if excerpt
4177                                .range
4178                                .context
4179                                .end
4180                                .cmp(&next, &excerpt.buffer)
4181                                .is_ge()
4182                            {
4183                                // record it and all following anchors that are within
4184                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4185                                result.extend(
4186                                    same_buffer_anchors
4187                                        .peeking_take_while(|a| {
4188                                            excerpt
4189                                                .range
4190                                                .context
4191                                                .end
4192                                                .cmp(a, &excerpt.buffer)
4193                                                .is_ge()
4194                                        })
4195                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4196                                );
4197                                match same_buffer_anchors.next() {
4198                                    Some(anchor) => next = anchor,
4199                                    None => continue 'anchors,
4200                                }
4201                            // anchor is after the excerpt, try the next one
4202                            } else {
4203                                continue 'excerpts;
4204                            }
4205                        }
4206                    }
4207                }
4208                // account for `next`
4209                result.push(None);
4210            }
4211            result.extend(same_buffer_anchors.map(|_| None));
4212        }
4213
4214        result
4215    }
4216
4217    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4218        &self,
4219        ranges: impl Iterator<Item = Range<T>>,
4220    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4221        ranges.flat_map(|range| {
4222            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4223                .into_iter()
4224        })
4225    }
4226
4227    pub fn range_to_buffer_ranges<R, T>(
4228        &self,
4229        range: R,
4230    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4231    where
4232        R: RangeBounds<T>,
4233        T: ToOffset,
4234    {
4235        self.range_to_buffer_ranges_with_context(range)
4236            .into_iter()
4237            .map(|(buffer, range, id, _context)| (buffer, range, id))
4238            .collect()
4239    }
4240
4241    pub fn range_to_buffer_ranges_with_context<R, T>(
4242        &self,
4243        range: R,
4244    ) -> Vec<(
4245        &BufferSnapshot,
4246        Range<BufferOffset>,
4247        ExcerptId,
4248        Range<text::Anchor>,
4249    )>
4250    where
4251        R: RangeBounds<T>,
4252        T: ToOffset,
4253    {
4254        let start = match range.start_bound() {
4255            Bound::Included(start) => start.to_offset(self),
4256            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4257            Bound::Unbounded => MultiBufferOffset::ZERO,
4258        };
4259        let end_bound = match range.end_bound() {
4260            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4261            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4262            Bound::Unbounded => Bound::Unbounded,
4263        };
4264        let bounds = (Bound::Included(start), end_bound);
4265
4266        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4267        cursor.seek(&start);
4268
4269        let mut result: Vec<(
4270            &BufferSnapshot,
4271            Range<BufferOffset>,
4272            ExcerptId,
4273            Range<text::Anchor>,
4274        )> = Vec::new();
4275        while let Some(region) = cursor.region() {
4276            let dominated_by_end_bound = match end_bound {
4277                Bound::Included(end) => region.range.start > end,
4278                Bound::Excluded(end) => region.range.start >= end,
4279                Bound::Unbounded => false,
4280            };
4281            if dominated_by_end_bound {
4282                break;
4283            }
4284            if region.is_main_buffer {
4285                let start_overshoot = start.saturating_sub(region.range.start);
4286                let end_offset = match end_bound {
4287                    Bound::Included(end) | Bound::Excluded(end) => end,
4288                    Bound::Unbounded => region.range.end,
4289                };
4290                let end_overshoot = end_offset.saturating_sub(region.range.start);
4291                let start = region
4292                    .buffer_range
4293                    .end
4294                    .min(region.buffer_range.start + start_overshoot);
4295                let end = region
4296                    .buffer_range
4297                    .end
4298                    .min(region.buffer_range.start + end_overshoot);
4299                let context = region.excerpt.range.context.clone();
4300                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4301                    *excerpt_id == region.excerpt.id && prev_range.end == start
4302                }) {
4303                    prev.1.end = end;
4304                } else {
4305                    result.push((region.buffer, start..end, region.excerpt.id, context));
4306                }
4307            }
4308            cursor.next();
4309        }
4310
4311        if let Some(excerpt) = cursor.excerpt() {
4312            let dominated_by_prev_excerpt =
4313                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4314            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4315                let excerpt_position = self.len();
4316                if bounds.contains(&excerpt_position) {
4317                    let buffer_offset =
4318                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4319                    let context = excerpt.range.context.clone();
4320                    result.push((
4321                        &excerpt.buffer,
4322                        buffer_offset..buffer_offset,
4323                        excerpt.id,
4324                        context,
4325                    ));
4326                }
4327            }
4328        }
4329
4330        result
4331    }
4332
4333    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4334        &self,
4335        range: Range<T>,
4336    ) -> impl Iterator<
4337        Item = (
4338            &BufferSnapshot,
4339            Range<BufferOffset>,
4340            ExcerptId,
4341            Option<Anchor>,
4342        ),
4343    > + '_ {
4344        let start = range.start.to_offset(self);
4345        let end = range.end.to_offset(self);
4346
4347        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4348        cursor.seek(&start);
4349
4350        std::iter::from_fn(move || {
4351            let region = cursor.region()?;
4352            if region.range.start > end {
4353                return None;
4354            }
4355            let start_overshoot = start.saturating_sub(region.range.start);
4356            let end_overshoot = end.saturating_sub(region.range.start);
4357            let start = region
4358                .buffer_range
4359                .end
4360                .min(region.buffer_range.start + start_overshoot);
4361            let end = region
4362                .buffer_range
4363                .end
4364                .min(region.buffer_range.start + end_overshoot);
4365
4366            let region_excerpt_id = region.excerpt.id;
4367            let deleted_hunk_anchor = if region.is_main_buffer {
4368                None
4369            } else {
4370                Some(self.anchor_before(region.range.start))
4371            };
4372            let result = (
4373                region.buffer,
4374                start..end,
4375                region_excerpt_id,
4376                deleted_hunk_anchor,
4377            );
4378            cursor.next();
4379            Some(result)
4380        })
4381    }
4382
4383    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4384    /// coordinates.
4385    ///
4386    /// The given callback will be called for every excerpt intersecting the given range. It will
4387    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4388    /// The callback should return an iterator of metadata items from that buffer, each paired
4389    /// with a buffer range.
4390    ///
4391    /// The returned iterator yields each of these metadata items, paired with its range in
4392    /// multi-buffer coordinates.
4393    fn lift_buffer_metadata<'a, MBD, M, I>(
4394        &'a self,
4395        query_range: Range<MBD>,
4396        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4397    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4398    where
4399        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4400        MBD: MultiBufferDimension
4401            + Ord
4402            + Sub<Output = MBD::TextDimension>
4403            + ops::Add<MBD::TextDimension, Output = MBD>
4404            + ops::AddAssign<MBD::TextDimension>,
4405        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4406            + ops::Add<Output = MBD::TextDimension>
4407            + AddAssign<MBD::TextDimension>
4408            + Ord,
4409    {
4410        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4411        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4412
4413        // Find the excerpt and buffer offset where the given range ends.
4414        cursor.seek(&query_range.end);
4415        let mut range_end = None;
4416        while let Some(region) = cursor.region() {
4417            if region.is_main_buffer {
4418                let mut buffer_end = region.buffer_range.start;
4419                let overshoot = if query_range.end > region.range.start {
4420                    query_range.end - region.range.start
4421                } else {
4422                    <MBD::TextDimension>::default()
4423                };
4424                buffer_end = buffer_end + overshoot;
4425                range_end = Some((region.excerpt.id, buffer_end));
4426                break;
4427            }
4428            cursor.next();
4429        }
4430
4431        cursor.seek(&query_range.start);
4432
4433        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4434            && region.range.start > MBD::default()
4435        {
4436            cursor.prev()
4437        } else if let Some(region) = cursor.region()
4438            && region.is_main_buffer
4439            && region.diff_hunk_status.is_some()
4440        {
4441            cursor.prev();
4442            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4443                cursor.next();
4444            }
4445        }
4446
4447        iter::from_fn(move || {
4448            loop {
4449                let excerpt = cursor.excerpt()?;
4450
4451                // If we have already retrieved metadata for this excerpt, continue to use it.
4452                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4453                    .as_mut()
4454                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4455                {
4456                    Some(metadata)
4457                }
4458                // Otherwise, compute the intersection of the input range with the excerpt's range,
4459                // and retrieve the metadata for the resulting range.
4460                else {
4461                    let region = cursor.region()?;
4462                    let mut buffer_start;
4463                    if region.is_main_buffer {
4464                        buffer_start = region.buffer_range.start;
4465                        if query_range.start > region.range.start {
4466                            let overshoot = query_range.start - region.range.start;
4467                            buffer_start = buffer_start + overshoot;
4468                        }
4469                        buffer_start = buffer_start.min(region.buffer_range.end);
4470                    } else {
4471                        buffer_start = cursor.main_buffer_position()?;
4472                    };
4473                    let mut buffer_end = excerpt
4474                        .range
4475                        .context
4476                        .end
4477                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4478                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4479                        && excerpt.id == end_excerpt_id
4480                    {
4481                        buffer_end = buffer_end.min(end_buffer_offset);
4482                    }
4483
4484                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4485                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4486                    })
4487                };
4488
4489                // Visit each metadata item.
4490                if let Some((metadata_buffer_range, metadata)) =
4491                    metadata_iter.and_then(Iterator::next)
4492                {
4493                    // Find the multibuffer regions that contain the start and end of
4494                    // the metadata item's range.
4495                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4496                        while let Some(region) = cursor.region() {
4497                            if (region.is_main_buffer
4498                                && (region.buffer_range.end >= metadata_buffer_range.start
4499                                    || cursor.is_at_end_of_excerpt()))
4500                                || (!region.is_main_buffer
4501                                    && region.buffer_range.start == metadata_buffer_range.start)
4502                            {
4503                                break;
4504                            }
4505                            cursor.next();
4506                        }
4507                    }
4508                    let start_region = cursor.region()?.clone();
4509                    while let Some(region) = cursor.region() {
4510                        if region.is_main_buffer
4511                            && (region.buffer_range.end > metadata_buffer_range.end
4512                                || cursor.is_at_end_of_excerpt())
4513                        {
4514                            break;
4515                        }
4516                        cursor.next();
4517                    }
4518                    let end_region = cursor.region();
4519
4520                    // Convert the metadata item's range into multibuffer coordinates.
4521                    let mut start_position = start_region.range.start;
4522                    let region_buffer_start = start_region.buffer_range.start;
4523                    if start_region.is_main_buffer
4524                        && metadata_buffer_range.start > region_buffer_start
4525                    {
4526                        start_position =
4527                            start_position + (metadata_buffer_range.start - region_buffer_start);
4528                        start_position = start_position.min(start_region.range.end);
4529                    }
4530
4531                    let mut end_position = self.max_position();
4532                    if let Some(end_region) = &end_region {
4533                        end_position = end_region.range.start;
4534                        debug_assert!(end_region.is_main_buffer);
4535                        let region_buffer_start = end_region.buffer_range.start;
4536                        if metadata_buffer_range.end > region_buffer_start {
4537                            end_position =
4538                                end_position + (metadata_buffer_range.end - region_buffer_start);
4539                        }
4540                        end_position = end_position.min(end_region.range.end);
4541                    }
4542
4543                    if start_position <= query_range.end && end_position >= query_range.start {
4544                        return Some((start_position..end_position, metadata, excerpt));
4545                    }
4546                }
4547                // When there are no more metadata items for this excerpt, move to the next excerpt.
4548                else {
4549                    current_excerpt_metadata.take();
4550                    if let Some((end_excerpt_id, _)) = range_end
4551                        && excerpt.id == end_excerpt_id
4552                    {
4553                        return None;
4554                    }
4555                    cursor.next_excerpt_forwards();
4556                }
4557            }
4558        })
4559    }
4560
4561    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4562        let offset = position.to_offset(self);
4563
4564        let mut cursor = self
4565            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4566            );
4567        cursor.seek(&DimensionPair {
4568            key: offset,
4569            value: None,
4570        });
4571        cursor.seek_to_start_of_current_excerpt();
4572        let excerpt = cursor.excerpt()?;
4573
4574        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4575        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4576        let current_position = self
4577            .anchor_before(offset)
4578            .text_anchor
4579            .to_offset(&excerpt.buffer);
4580
4581        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4582            if let Some(main_buffer) = &diff.main_buffer {
4583                for hunk in diff
4584                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4585                {
4586                    if hunk.diff_base_byte_range.end >= current_position {
4587                        continue;
4588                    }
4589                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4590                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4591                    return Some(MultiBufferRow(start.row));
4592                }
4593            } else {
4594                let excerpt_end = excerpt
4595                    .buffer
4596                    .anchor_before(excerpt_end.min(current_position));
4597                for hunk in diff.hunks_intersecting_range_rev(
4598                    excerpt.range.context.start..excerpt_end,
4599                    &excerpt.buffer,
4600                ) {
4601                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4602                    if hunk_end >= current_position {
4603                        continue;
4604                    }
4605                    let start =
4606                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4607                    return Some(MultiBufferRow(start.row));
4608                }
4609            }
4610        }
4611
4612        loop {
4613            cursor.prev_excerpt();
4614            let excerpt = cursor.excerpt()?;
4615
4616            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4617                continue;
4618            };
4619            if let Some(main_buffer) = &diff.main_buffer {
4620                let Some(hunk) = diff
4621                    .hunks_intersecting_base_text_range_rev(
4622                        excerpt.range.context.to_offset(&excerpt.buffer),
4623                        main_buffer,
4624                    )
4625                    .next()
4626                else {
4627                    continue;
4628                };
4629                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4630                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4631                return Some(MultiBufferRow(start.row));
4632            } else {
4633                let Some(hunk) = diff
4634                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4635                    .next()
4636                else {
4637                    continue;
4638                };
4639                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4640                return Some(MultiBufferRow(start.row));
4641            }
4642        }
4643    }
4644
4645    pub fn has_diff_hunks(&self) -> bool {
4646        self.diffs.values().any(|diff| !diff.is_empty())
4647    }
4648
4649    pub fn is_inside_word<T: ToOffset>(
4650        &self,
4651        position: T,
4652        scope_context: Option<CharScopeContext>,
4653    ) -> bool {
4654        let position = position.to_offset(self);
4655        let classifier = self
4656            .char_classifier_at(position)
4657            .scope_context(scope_context);
4658        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4659        let prev_char_kind = self
4660            .reversed_chars_at(position)
4661            .next()
4662            .map(|c| classifier.kind(c));
4663        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4664    }
4665
4666    pub fn surrounding_word<T: ToOffset>(
4667        &self,
4668        start: T,
4669        scope_context: Option<CharScopeContext>,
4670    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4671        let mut start = start.to_offset(self);
4672        let mut end = start;
4673        let mut next_chars = self.chars_at(start).peekable();
4674        let mut prev_chars = self.reversed_chars_at(start).peekable();
4675
4676        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4677
4678        let word_kind = cmp::max(
4679            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4680            next_chars.peek().copied().map(|c| classifier.kind(c)),
4681        );
4682
4683        for ch in prev_chars {
4684            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4685                start -= ch.len_utf8();
4686            } else {
4687                break;
4688            }
4689        }
4690
4691        for ch in next_chars {
4692            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4693                end += ch.len_utf8();
4694            } else {
4695                break;
4696            }
4697        }
4698
4699        (start..end, word_kind)
4700    }
4701
4702    pub fn char_kind_before<T: ToOffset>(
4703        &self,
4704        start: T,
4705        scope_context: Option<CharScopeContext>,
4706    ) -> Option<CharKind> {
4707        let start = start.to_offset(self);
4708        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4709        self.reversed_chars_at(start)
4710            .next()
4711            .map(|ch| classifier.kind(ch))
4712    }
4713
4714    pub fn is_singleton(&self) -> bool {
4715        self.singleton
4716    }
4717
4718    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4719        if self.singleton {
4720            self.excerpts
4721                .iter()
4722                .next()
4723                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4724        } else {
4725            None
4726        }
4727    }
4728
4729    pub fn len(&self) -> MultiBufferOffset {
4730        self.diff_transforms.summary().output.len
4731    }
4732
4733    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4734        MBD::from_summary(&self.text_summary())
4735    }
4736
4737    pub fn is_empty(&self) -> bool {
4738        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4739    }
4740
4741    pub fn widest_line_number(&self) -> u32 {
4742        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4743        self.excerpts.summary().widest_line_number + 1
4744    }
4745
4746    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4747        let range = range.start.to_offset(self)..range.end.to_offset(self);
4748        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4749        excerpts.seek(&range.start);
4750
4751        let mut chunk;
4752        let mut has_trailing_newline;
4753        let excerpt_bytes;
4754        if let Some(region) = excerpts.region() {
4755            let mut bytes = region.buffer.bytes_in_range(
4756                region.buffer_range.start + (range.start - region.range.start)
4757                    ..(region.buffer_range.start + (range.end - region.range.start))
4758                        .min(region.buffer_range.end),
4759            );
4760            chunk = bytes.next().unwrap_or(&[][..]);
4761            excerpt_bytes = Some(bytes);
4762            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4763            if chunk.is_empty() && has_trailing_newline {
4764                chunk = b"\n";
4765                has_trailing_newline = false;
4766            }
4767        } else {
4768            chunk = &[][..];
4769            excerpt_bytes = None;
4770            has_trailing_newline = false;
4771        };
4772
4773        MultiBufferBytes {
4774            range,
4775            cursor: excerpts,
4776            excerpt_bytes,
4777            has_trailing_newline,
4778            chunk,
4779        }
4780    }
4781
4782    pub fn reversed_bytes_in_range<T: ToOffset>(
4783        &self,
4784        range: Range<T>,
4785    ) -> ReversedMultiBufferBytes<'_> {
4786        let range = range.start.to_offset(self)..range.end.to_offset(self);
4787        let mut chunks = self.reversed_chunks_in_range(range.clone());
4788        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4789        ReversedMultiBufferBytes {
4790            range,
4791            chunks,
4792            chunk,
4793        }
4794    }
4795
4796    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4797        let mut cursor = self.cursor::<Point, Point>();
4798        cursor.seek(&Point::new(start_row.0, 0));
4799        let mut result = MultiBufferRows {
4800            point: Point::new(0, 0),
4801            is_empty: self.excerpts.is_empty(),
4802            is_singleton: self.is_singleton(),
4803            cursor,
4804        };
4805        result.seek(start_row);
4806        result
4807    }
4808
4809    pub fn chunks<T: ToOffset>(
4810        &self,
4811        range: Range<T>,
4812        language_aware: bool,
4813    ) -> MultiBufferChunks<'_> {
4814        let mut chunks = MultiBufferChunks {
4815            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4816                ..ExcerptDimension(MultiBufferOffset::ZERO),
4817            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4818            excerpts: self.excerpts.cursor(()),
4819            diff_transforms: self.diff_transforms.cursor(()),
4820            diffs: &self.diffs,
4821            diff_base_chunks: None,
4822            excerpt_chunks: None,
4823            buffer_chunk: None,
4824            language_aware,
4825        };
4826        let range = range.start.to_offset(self)..range.end.to_offset(self);
4827        chunks.seek(range);
4828        chunks
4829    }
4830
4831    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4832        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4833    }
4834
4835    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4836        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4837    }
4838
4839    pub fn clip_offset_utf16(
4840        &self,
4841        offset: MultiBufferOffsetUtf16,
4842        bias: Bias,
4843    ) -> MultiBufferOffsetUtf16 {
4844        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4845    }
4846
4847    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4848        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4849            buffer.clip_point_utf16(Unclipped(point), bias)
4850        })
4851    }
4852
4853    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4854        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4855    }
4856
4857    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4858        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4859    }
4860
4861    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4862        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4863    }
4864
4865    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4866        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4867    }
4868
4869    #[instrument(skip_all)]
4870    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4871        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4872    }
4873
4874    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4875        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4876    }
4877
4878    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4879        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4880    }
4881
4882    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4883        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4884    }
4885
4886    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4887        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4888    }
4889
4890    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4891        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4892    }
4893
4894    fn clip_dimension<MBD, BD>(
4895        &self,
4896        position: MBD,
4897        bias: Bias,
4898        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4899    ) -> MBD
4900    where
4901        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4902        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4903    {
4904        let mut cursor = self.cursor::<MBD, BD>();
4905        cursor.seek(&position);
4906        if let Some(region) = cursor.region() {
4907            if position >= region.range.end {
4908                return region.range.end;
4909            }
4910            let overshoot = position - region.range.start;
4911            let mut buffer_position = region.buffer_range.start;
4912            buffer_position += overshoot;
4913            let clipped_buffer_position =
4914                clip_buffer_position(region.buffer, buffer_position, bias);
4915            let mut position = region.range.start;
4916            position += clipped_buffer_position - region.buffer_range.start;
4917            position
4918        } else {
4919            self.max_position()
4920        }
4921    }
4922
4923    #[instrument(skip_all)]
4924    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4925        &self,
4926        key: MBR1,
4927        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4928    ) -> MBR2
4929    where
4930        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4931        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4932        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4933        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4934    {
4935        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4936        cursor.seek(&DimensionPair { key, value: None });
4937        if let Some(region) = cursor.region() {
4938            if key >= region.range.end.key {
4939                return region.range.end.value.unwrap();
4940            }
4941            let start_key = region.range.start.key;
4942            let start_value = region.range.start.value.unwrap();
4943            let buffer_start_key = region.buffer_range.start.key;
4944            let buffer_start_value = region.buffer_range.start.value.unwrap();
4945            let mut buffer_key = buffer_start_key;
4946            buffer_key += key - start_key;
4947            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4948            let mut result = start_value;
4949            result += buffer_value - buffer_start_value;
4950            result
4951        } else {
4952            self.max_position()
4953        }
4954    }
4955
4956    pub fn point_to_buffer_offset<T: ToOffset>(
4957        &self,
4958        point: T,
4959    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4960        let offset = point.to_offset(self);
4961        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4962        cursor.seek(&offset);
4963        let region = cursor.region()?;
4964        let overshoot = offset - region.range.start;
4965        let buffer_offset = region.buffer_range.start + overshoot;
4966        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4967            && region.has_trailing_newline
4968            && !region.is_main_buffer
4969        {
4970            let main_buffer_position = cursor.main_buffer_position()?;
4971            let buffer_snapshot = &cursor.excerpt()?.buffer;
4972            return Some((buffer_snapshot, main_buffer_position));
4973        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4974            return None;
4975        }
4976        Some((region.buffer, buffer_offset))
4977    }
4978
4979    pub fn point_to_buffer_point(
4980        &self,
4981        point: Point,
4982    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4983        let mut cursor = self.cursor::<Point, Point>();
4984        cursor.seek(&point);
4985        let region = cursor.region()?;
4986        let overshoot = point - region.range.start;
4987        let buffer_point = region.buffer_range.start + overshoot;
4988        let excerpt = cursor.excerpt()?;
4989        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4990            && region.has_trailing_newline
4991            && !region.is_main_buffer
4992        {
4993            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4994        } else if buffer_point > region.buffer.max_point() {
4995            return None;
4996        }
4997        Some((region.buffer, buffer_point, excerpt.id))
4998    }
4999
5000    pub fn suggested_indents(
5001        &self,
5002        rows: impl IntoIterator<Item = u32>,
5003        cx: &App,
5004    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5005        let mut result = BTreeMap::new();
5006        self.suggested_indents_callback(
5007            rows,
5008            |row, indent| {
5009                result.insert(row, indent);
5010                ControlFlow::Continue(())
5011            },
5012            cx,
5013        );
5014        result
5015    }
5016
5017    // move this to be a generator once those are a thing
5018    pub fn suggested_indents_callback(
5019        &self,
5020        rows: impl IntoIterator<Item = u32>,
5021        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5022        cx: &App,
5023    ) {
5024        let mut rows_for_excerpt = Vec::new();
5025        let mut cursor = self.cursor::<Point, Point>();
5026        let mut rows = rows.into_iter().peekable();
5027        let mut prev_row = u32::MAX;
5028        let mut prev_language_indent_size = IndentSize::default();
5029
5030        while let Some(row) = rows.next() {
5031            cursor.seek(&Point::new(row, 0));
5032            let Some(region) = cursor.region() else {
5033                continue;
5034            };
5035
5036            // Retrieve the language and indent size once for each disjoint region being indented.
5037            let single_indent_size = if row.saturating_sub(1) == prev_row {
5038                prev_language_indent_size
5039            } else {
5040                region
5041                    .buffer
5042                    .language_indent_size_at(Point::new(row, 0), cx)
5043            };
5044            prev_language_indent_size = single_indent_size;
5045            prev_row = row;
5046
5047            let start_buffer_row = region.buffer_range.start.row;
5048            let start_multibuffer_row = region.range.start.row;
5049            let end_multibuffer_row = region.range.end.row;
5050
5051            rows_for_excerpt.push(row);
5052            while let Some(next_row) = rows.peek().copied() {
5053                if end_multibuffer_row > next_row {
5054                    rows_for_excerpt.push(next_row);
5055                    rows.next();
5056                } else {
5057                    break;
5058                }
5059            }
5060
5061            let buffer_rows = rows_for_excerpt
5062                .drain(..)
5063                .map(|row| start_buffer_row + row - start_multibuffer_row);
5064            let buffer_indents = region
5065                .buffer
5066                .suggested_indents(buffer_rows, single_indent_size);
5067            for (row, indent) in buffer_indents {
5068                if cb(
5069                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5070                    indent,
5071                )
5072                .is_break()
5073                {
5074                    return;
5075                }
5076            }
5077        }
5078    }
5079
5080    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5081        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5082            let mut size = buffer.indent_size_for_line(range.start.row);
5083            size.len = size
5084                .len
5085                .min(range.end.column)
5086                .saturating_sub(range.start.column);
5087            size
5088        } else {
5089            IndentSize::spaces(0)
5090        }
5091    }
5092
5093    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5094        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5095            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5096        } else {
5097            LineIndent::spaces(0)
5098        }
5099    }
5100
5101    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5102        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5103
5104        if self.language_settings(cx).extend_comment_on_newline
5105            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5106        {
5107            let delimiters = language_scope.line_comment_prefixes();
5108            for delimiter in delimiters {
5109                if *self
5110                    .chars_at(Point::new(row.0, indent.len() as u32))
5111                    .take(delimiter.chars().count())
5112                    .collect::<String>()
5113                    .as_str()
5114                    == **delimiter
5115                {
5116                    indent.push_str(delimiter);
5117                    break;
5118                }
5119            }
5120        }
5121
5122        indent
5123    }
5124
5125    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5126    where
5127        T: ToOffset,
5128    {
5129        for char in self.reversed_chars_at(position) {
5130            if !char.is_whitespace() {
5131                return false;
5132            }
5133            if char == '\n' {
5134                return true;
5135            }
5136        }
5137        true
5138    }
5139
5140    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5141        while row.0 > 0 {
5142            row.0 -= 1;
5143            if !self.is_line_blank(row) {
5144                return Some(row);
5145            }
5146        }
5147        None
5148    }
5149
5150    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5151        if let Some((_, range)) = self.buffer_line_for_row(row) {
5152            range.end.column - range.start.column
5153        } else {
5154            0
5155        }
5156    }
5157
5158    pub fn buffer_line_for_row(
5159        &self,
5160        row: MultiBufferRow,
5161    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5162        let mut cursor = self.cursor::<Point, Point>();
5163        let point = Point::new(row.0, 0);
5164        cursor.seek(&point);
5165        let region = cursor.region()?;
5166        let overshoot = point.min(region.range.end) - region.range.start;
5167        let buffer_point = region.buffer_range.start + overshoot;
5168        if buffer_point.row > region.buffer_range.end.row {
5169            return None;
5170        }
5171        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5172        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5173            .min(region.buffer_range.end);
5174        Some((region.buffer, line_start..line_end))
5175    }
5176
5177    pub fn max_point(&self) -> Point {
5178        self.text_summary().lines
5179    }
5180
5181    pub fn max_row(&self) -> MultiBufferRow {
5182        MultiBufferRow(self.text_summary().lines.row)
5183    }
5184
5185    pub fn text_summary(&self) -> MBTextSummary {
5186        self.diff_transforms.summary().output
5187    }
5188
5189    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5190    where
5191        MBD: MultiBufferDimension + AddAssign,
5192        O: ToOffset,
5193    {
5194        let range = range.start.to_offset(self)..range.end.to_offset(self);
5195        let mut cursor = self
5196            .diff_transforms
5197            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5198        cursor.seek(&range.start, Bias::Right);
5199
5200        let Some(first_transform) = cursor.item() else {
5201            return MBD::from_summary(&MBTextSummary::default());
5202        };
5203
5204        let diff_transform_start = cursor.start().0;
5205        let diff_transform_end = cursor.end().0;
5206        let diff_start = range.start;
5207        let start_overshoot = diff_start - diff_transform_start;
5208        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5209
5210        let mut result = match first_transform {
5211            DiffTransform::BufferContent { .. } => {
5212                let excerpt_start = cursor.start().1 + start_overshoot;
5213                let excerpt_end = cursor.start().1 + end_overshoot;
5214                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5215            }
5216            DiffTransform::DeletedHunk {
5217                buffer_id,
5218                base_text_byte_range,
5219                has_trailing_newline,
5220                ..
5221            } => {
5222                let buffer_start = base_text_byte_range.start + start_overshoot;
5223                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5224                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5225                    panic!("{:?} is in non-existent deleted hunk", range.start)
5226                };
5227
5228                let include_trailing_newline =
5229                    *has_trailing_newline && range.end >= diff_transform_end;
5230                if include_trailing_newline {
5231                    buffer_end -= 1;
5232                }
5233
5234                let mut summary = base_text
5235                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5236
5237                if include_trailing_newline {
5238                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5239                        &TextSummary::newline(),
5240                    ))
5241                }
5242
5243                let mut result = MBD::default();
5244                result.add_text_dim(&summary);
5245                result
5246            }
5247        };
5248        if range.end < diff_transform_end {
5249            return result;
5250        }
5251
5252        cursor.next();
5253        result.add_mb_text_summary(
5254            &cursor
5255                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5256                .0,
5257        );
5258
5259        let Some(last_transform) = cursor.item() else {
5260            return result;
5261        };
5262
5263        let overshoot = range.end - cursor.start().0;
5264        let suffix = match last_transform {
5265            DiffTransform::BufferContent { .. } => {
5266                let end = cursor.start().1 + overshoot;
5267                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5268            }
5269            DiffTransform::DeletedHunk {
5270                base_text_byte_range,
5271                buffer_id,
5272                has_trailing_newline,
5273                ..
5274            } => {
5275                let buffer_end = base_text_byte_range.start + overshoot;
5276                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5277                    panic!("{:?} is in non-existent deleted hunk", range.end)
5278                };
5279
5280                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5281                    base_text_byte_range.start..buffer_end,
5282                );
5283                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5284                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5285                        &TextSummary::from("\n"),
5286                    ))
5287                }
5288
5289                let mut result = MBD::default();
5290                result.add_text_dim(&suffix);
5291                result
5292            }
5293        };
5294
5295        result += suffix;
5296        result
5297    }
5298
5299    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5300    where
5301        MBD: MultiBufferDimension + AddAssign,
5302    {
5303        let mut summary = MBD::default();
5304        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5305        cursor.seek(&range.start, Bias::Right);
5306        if let Some(excerpt) = cursor.item() {
5307            let mut end_before_newline = cursor.end();
5308            if excerpt.has_trailing_newline {
5309                end_before_newline -= 1;
5310            }
5311
5312            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5313            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5314            let end_in_excerpt =
5315                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5316            summary.add_text_dim(
5317                &excerpt
5318                    .buffer
5319                    .text_summary_for_range::<MBD::TextDimension, _>(
5320                        start_in_excerpt..end_in_excerpt,
5321                    ),
5322            );
5323
5324            if range.end > end_before_newline {
5325                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5326            }
5327
5328            cursor.next();
5329        }
5330
5331        if range.end > *cursor.start() {
5332            summary += cursor
5333                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5334                .0;
5335            if let Some(excerpt) = cursor.item() {
5336                range.end = cmp::max(*cursor.start(), range.end);
5337
5338                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5339                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5340                summary.add_text_dim(
5341                    &excerpt
5342                        .buffer
5343                        .text_summary_for_range::<MBD::TextDimension, _>(
5344                            excerpt_start..end_in_excerpt,
5345                        ),
5346                );
5347            }
5348        }
5349
5350        summary
5351    }
5352
5353    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5354    where
5355        MBD: MultiBufferDimension
5356            + Ord
5357            + Sub<Output = MBD::TextDimension>
5358            + Sub<MBD::TextDimension, Output = MBD>
5359            + AddAssign<MBD::TextDimension>
5360            + Add<MBD::TextDimension, Output = MBD>,
5361        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5362    {
5363        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5364        let locator = self.excerpt_locator_for_id(excerpt_id);
5365        let (start, _, mut item) = self
5366            .excerpts
5367            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5368        let mut start = MBD::from_summary(&start.text);
5369        if item.is_none() && excerpt_id == ExcerptId::max() {
5370            item = self.excerpts.last();
5371            if let Some(last_summary) = self.excerpts.last_summary() {
5372                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5373            }
5374        }
5375
5376        if self.diff_transforms.is_empty() {
5377            let excerpt_start_position = ExcerptDimension(start);
5378            if let Some(excerpt) = item {
5379                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5380                    return excerpt_start_position.0;
5381                }
5382                let excerpt_buffer_start = excerpt
5383                    .range
5384                    .context
5385                    .start
5386                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5387                let excerpt_buffer_end = excerpt
5388                    .range
5389                    .context
5390                    .end
5391                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5392                let buffer_summary = anchor
5393                    .text_anchor
5394                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5395                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5396                let mut position = excerpt_start_position;
5397                if summary > excerpt_buffer_start {
5398                    position += summary - excerpt_buffer_start;
5399                }
5400
5401                position.0
5402            } else {
5403                excerpt_start_position.0
5404            }
5405        } else {
5406            let mut diff_transforms_cursor = self
5407                .diff_transforms
5408                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5409            diff_transforms_cursor.next();
5410
5411            let excerpt_start_position = ExcerptDimension(start);
5412            if let Some(excerpt) = item {
5413                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5414                    return self.resolve_summary_for_anchor(
5415                        &Anchor::min(),
5416                        excerpt_start_position,
5417                        &mut diff_transforms_cursor,
5418                    );
5419                }
5420                let excerpt_buffer_start = excerpt
5421                    .range
5422                    .context
5423                    .start
5424                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5425                let excerpt_buffer_end = excerpt
5426                    .range
5427                    .context
5428                    .end
5429                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5430                let buffer_summary = anchor
5431                    .text_anchor
5432                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5433                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5434                let mut position = excerpt_start_position;
5435                if summary > excerpt_buffer_start {
5436                    position += summary - excerpt_buffer_start;
5437                }
5438
5439                if diff_transforms_cursor.start().0 < position {
5440                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5441                }
5442                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5443            } else {
5444                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5445                self.resolve_summary_for_anchor(
5446                    &Anchor::max(),
5447                    excerpt_start_position,
5448                    &mut diff_transforms_cursor,
5449                )
5450            }
5451        }
5452    }
5453
5454    fn resolve_summary_for_anchor<MBD>(
5455        &self,
5456        anchor: &Anchor,
5457        excerpt_position: ExcerptDimension<MBD>,
5458        diff_transforms: &mut Cursor<
5459            DiffTransform,
5460            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5461        >,
5462    ) -> MBD
5463    where
5464        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5465    {
5466        loop {
5467            let transform_end_position = diff_transforms.end().0;
5468            let at_transform_end =
5469                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5470            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5471                diff_transforms.next();
5472                continue;
5473            }
5474
5475            let mut position = diff_transforms.start().1;
5476            match diff_transforms.item() {
5477                Some(DiffTransform::DeletedHunk {
5478                    buffer_id,
5479                    base_text_byte_range,
5480                    ..
5481                }) => {
5482                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5483                        && let Some(base_text) =
5484                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5485                        && diff_base_anchor.is_valid(&base_text)
5486                    {
5487                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5488                        if base_text_offset >= base_text_byte_range.start
5489                            && base_text_offset <= base_text_byte_range.end
5490                        {
5491                            let position_in_hunk = base_text
5492                                .text_summary_for_range::<MBD::TextDimension, _>(
5493                                    base_text_byte_range.start..base_text_offset,
5494                                );
5495                            position.0.add_text_dim(&position_in_hunk);
5496                        } else if at_transform_end {
5497                            diff_transforms.next();
5498                            continue;
5499                        }
5500                    }
5501                }
5502                _ => {
5503                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5504                        diff_transforms.next();
5505                        continue;
5506                    }
5507                    let overshoot = excerpt_position - diff_transforms.start().0;
5508                    position += overshoot;
5509                }
5510            }
5511
5512            return position.0;
5513        }
5514    }
5515
5516    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5517        let mut cursor = self
5518            .excerpts
5519            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5520        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5521
5522        cursor.seek(&Some(locator), Bias::Left);
5523        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5524            cursor.prev();
5525        }
5526
5527        let mut position = cursor.start().1;
5528        if let Some(excerpt) = cursor.item()
5529            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5530        {
5531            let excerpt_buffer_start = excerpt
5532                .buffer
5533                .offset_for_anchor(&excerpt.range.context.start);
5534            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5535            let buffer_position = cmp::min(
5536                excerpt_buffer_end,
5537                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5538            );
5539            if buffer_position > excerpt_buffer_start {
5540                position += buffer_position - excerpt_buffer_start;
5541            }
5542        }
5543        position
5544    }
5545
5546    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5547        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5548            excerpt_id = *replacement;
5549        }
5550        excerpt_id
5551    }
5552
5553    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5554    where
5555        MBD: MultiBufferDimension
5556            + Ord
5557            + Sub<Output = MBD::TextDimension>
5558            + AddAssign<MBD::TextDimension>,
5559        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5560        I: 'a + IntoIterator<Item = &'a Anchor>,
5561    {
5562        let mut anchors = anchors.into_iter().peekable();
5563        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5564        let mut diff_transforms_cursor = self
5565            .diff_transforms
5566            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5567        diff_transforms_cursor.next();
5568
5569        let mut summaries = Vec::new();
5570        while let Some(anchor) = anchors.peek() {
5571            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5572
5573            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5574                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5575            });
5576
5577            let locator = self.excerpt_locator_for_id(excerpt_id);
5578            cursor.seek_forward(locator, Bias::Left);
5579            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5580                cursor.prev();
5581            }
5582
5583            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5584            if let Some(excerpt) = cursor.item() {
5585                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5586                    let position = self.resolve_summary_for_anchor(
5587                        &Anchor::min(),
5588                        excerpt_start_position,
5589                        &mut diff_transforms_cursor,
5590                    );
5591                    summaries.extend(excerpt_anchors.map(|_| position));
5592                    continue;
5593                }
5594                let excerpt_buffer_start = excerpt
5595                    .range
5596                    .context
5597                    .start
5598                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5599                let excerpt_buffer_end = excerpt
5600                    .range
5601                    .context
5602                    .end
5603                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5604                for (buffer_summary, anchor) in excerpt
5605                    .buffer
5606                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5607                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5608                    )
5609                {
5610                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5611                    let mut position = excerpt_start_position;
5612                    if summary > excerpt_buffer_start {
5613                        position += summary - excerpt_buffer_start;
5614                    }
5615
5616                    if diff_transforms_cursor.start().0 < position {
5617                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5618                    }
5619
5620                    summaries.push(self.resolve_summary_for_anchor(
5621                        anchor,
5622                        position,
5623                        &mut diff_transforms_cursor,
5624                    ));
5625                }
5626            } else {
5627                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5628                let position = self.resolve_summary_for_anchor(
5629                    &Anchor::max(),
5630                    excerpt_start_position,
5631                    &mut diff_transforms_cursor,
5632                );
5633                summaries.extend(excerpt_anchors.map(|_| position));
5634            }
5635        }
5636
5637        summaries
5638    }
5639
5640    pub fn dimensions_from_points<'a, MBD>(
5641        &'a self,
5642        points: impl 'a + IntoIterator<Item = Point>,
5643    ) -> impl 'a + Iterator<Item = MBD>
5644    where
5645        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5646    {
5647        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5648        cursor.seek(&DimensionPair {
5649            key: Point::default(),
5650            value: None,
5651        });
5652        let mut points = points.into_iter();
5653        iter::from_fn(move || {
5654            let point = points.next()?;
5655
5656            cursor.seek_forward(&DimensionPair {
5657                key: point,
5658                value: None,
5659            });
5660
5661            if let Some(region) = cursor.region() {
5662                let overshoot = point - region.range.start.key;
5663                let buffer_point = region.buffer_range.start + overshoot;
5664                let mut position = region.range.start.value.unwrap();
5665                position.add_text_dim(
5666                    &region
5667                        .buffer
5668                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5669                );
5670                if point == region.range.end.key && region.has_trailing_newline {
5671                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5672                }
5673                Some(position)
5674            } else {
5675                Some(MBD::from_summary(&self.text_summary()))
5676            }
5677        })
5678    }
5679
5680    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5681    where
5682        I: 'a + IntoIterator<Item = &'a Anchor>,
5683    {
5684        let mut anchors = anchors.into_iter().enumerate().peekable();
5685        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5686        cursor.next();
5687
5688        let mut result = Vec::new();
5689
5690        while let Some((_, anchor)) = anchors.peek() {
5691            let old_excerpt_id = anchor.excerpt_id;
5692
5693            // Find the location where this anchor's excerpt should be.
5694            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5695            cursor.seek_forward(&Some(old_locator), Bias::Left);
5696
5697            let next_excerpt = cursor.item();
5698            let prev_excerpt = cursor.prev_item();
5699
5700            // Process all of the anchors for this excerpt.
5701            while let Some((anchor_ix, &anchor)) =
5702                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5703            {
5704                let mut anchor = anchor;
5705
5706                // Leave min and max anchors unchanged if invalid or
5707                // if the old excerpt still exists at this location
5708                let mut kept_position = next_excerpt
5709                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5710                    || old_excerpt_id == ExcerptId::max()
5711                    || old_excerpt_id == ExcerptId::min();
5712
5713                // If the old excerpt no longer exists at this location, then attempt to
5714                // find an equivalent position for this anchor in an adjacent excerpt.
5715                if !kept_position {
5716                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5717                        if excerpt.contains(&anchor) {
5718                            anchor.excerpt_id = excerpt.id;
5719                            kept_position = true;
5720                            break;
5721                        }
5722                    }
5723                }
5724
5725                // If there's no adjacent excerpt that contains the anchor's position,
5726                // then report that the anchor has lost its position.
5727                if !kept_position {
5728                    anchor = if let Some(excerpt) = next_excerpt {
5729                        let mut text_anchor = excerpt
5730                            .range
5731                            .context
5732                            .start
5733                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5734                        if text_anchor
5735                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5736                            .is_gt()
5737                        {
5738                            text_anchor = excerpt.range.context.end;
5739                        }
5740                        Anchor::in_buffer(excerpt.id, text_anchor)
5741                    } else if let Some(excerpt) = prev_excerpt {
5742                        let mut text_anchor = excerpt
5743                            .range
5744                            .context
5745                            .end
5746                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5747                        if text_anchor
5748                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5749                            .is_lt()
5750                        {
5751                            text_anchor = excerpt.range.context.start;
5752                        }
5753                        Anchor::in_buffer(excerpt.id, text_anchor)
5754                    } else if anchor.text_anchor.bias == Bias::Left {
5755                        Anchor::min()
5756                    } else {
5757                        Anchor::max()
5758                    };
5759                }
5760
5761                result.push((anchor_ix, anchor, kept_position));
5762            }
5763        }
5764        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5765        result
5766    }
5767
5768    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5769        self.anchor_at(position, Bias::Left)
5770    }
5771
5772    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5773        self.anchor_at(position, Bias::Right)
5774    }
5775
5776    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5777        let offset = position.to_offset(self);
5778
5779        // Find the given position in the diff transforms. Determine the corresponding
5780        // offset in the excerpts, and whether the position is within a deleted hunk.
5781        let mut diff_transforms = self
5782            .diff_transforms
5783            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5784        diff_transforms.seek(&offset, Bias::Right);
5785
5786        if offset == diff_transforms.start().0
5787            && bias == Bias::Left
5788            && let Some(prev_item) = diff_transforms.prev_item()
5789            && let DiffTransform::DeletedHunk { .. } = prev_item
5790        {
5791            diff_transforms.prev();
5792        }
5793        let offset_in_transform = offset - diff_transforms.start().0;
5794        let mut excerpt_offset = diff_transforms.start().1;
5795        let mut diff_base_anchor = None;
5796        if let Some(DiffTransform::DeletedHunk {
5797            buffer_id,
5798            base_text_byte_range,
5799            has_trailing_newline,
5800            ..
5801        }) = diff_transforms.item()
5802        {
5803            let diff = self.diffs.get(buffer_id).expect("missing diff");
5804            if offset_in_transform > base_text_byte_range.len() {
5805                debug_assert!(*has_trailing_newline);
5806                bias = Bias::Right;
5807            } else {
5808                diff_base_anchor = Some(
5809                    diff.base_text()
5810                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5811                );
5812                bias = Bias::Left;
5813            }
5814        } else {
5815            excerpt_offset += MultiBufferOffset(offset_in_transform);
5816        };
5817
5818        let mut excerpts = self
5819            .excerpts
5820            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5821        excerpts.seek(&excerpt_offset, Bias::Right);
5822        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5823            excerpts.prev();
5824        }
5825        if let Some(excerpt) = excerpts.item() {
5826            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5827            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5828                overshoot -= 1;
5829                bias = Bias::Right;
5830            }
5831
5832            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5833            let text_anchor =
5834                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5835            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5836            match diff_base_anchor {
5837                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5838                None => anchor,
5839            }
5840        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5841        {
5842            Anchor::min()
5843        } else {
5844            Anchor::max()
5845        }
5846    }
5847
5848    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5849    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5850        let (excerpt, buffer, _) = self.as_singleton()?;
5851        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5852            Some(Anchor::in_buffer(*excerpt, text_anchor))
5853        } else {
5854            None
5855        }
5856    }
5857
5858    /// Returns an anchor for the given excerpt and text anchor,
5859    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5860    pub fn anchor_range_in_excerpt(
5861        &self,
5862        excerpt_id: ExcerptId,
5863        text_anchor: Range<text::Anchor>,
5864    ) -> Option<Range<Anchor>> {
5865        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5866
5867        Some(
5868            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5869                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5870        )
5871    }
5872
5873    /// Returns an anchor for the given excerpt and text anchor,
5874    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5875    pub fn anchor_in_excerpt(
5876        &self,
5877        excerpt_id: ExcerptId,
5878        text_anchor: text::Anchor,
5879    ) -> Option<Anchor> {
5880        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5881        Self::anchor_in_excerpt_(excerpt, text_anchor)
5882    }
5883
5884    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5885    pub fn anchors_in_excerpt(
5886        &self,
5887        excerpt_id: ExcerptId,
5888        text_anchors: impl IntoIterator<Item = text::Anchor>,
5889    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5890        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5891        Some(
5892            text_anchors
5893                .into_iter()
5894                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5895        )
5896    }
5897
5898    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5899        match text_anchor.buffer_id {
5900            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5901            Some(_) => return None,
5902            None if text_anchor.is_max() || text_anchor.is_min() => {
5903                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5904            }
5905            None => return None,
5906        }
5907
5908        let context = &excerpt.range.context;
5909        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5910            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5911        {
5912            return None;
5913        }
5914
5915        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5916    }
5917
5918    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5919        Some(self.excerpt(excerpt_id)?.range.context.clone())
5920    }
5921
5922    pub fn excerpt_range_for_excerpt(
5923        &self,
5924        excerpt_id: ExcerptId,
5925    ) -> Option<ExcerptRange<text::Anchor>> {
5926        Some(self.excerpt(excerpt_id)?.range.clone())
5927    }
5928
5929    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5930        if anchor.is_min() || anchor.is_max() {
5931            // todo(lw): should be `!self.is_empty()`
5932            true
5933        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5934            excerpt.buffer.can_resolve(&anchor.text_anchor)
5935        } else {
5936            false
5937        }
5938    }
5939
5940    pub fn excerpts(
5941        &self,
5942    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5943        self.excerpts
5944            .iter()
5945            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5946    }
5947
5948    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5949    where
5950        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5951        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5952    {
5953        let excerpts = self.excerpts.cursor(());
5954        let diff_transforms = self.diff_transforms.cursor(());
5955        MultiBufferCursor {
5956            excerpts,
5957            diff_transforms,
5958            diffs: &self.diffs,
5959            cached_region: OnceCell::new(),
5960        }
5961    }
5962
5963    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5964        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5965        let mut excerpts = self
5966            .excerpts
5967            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5968        excerpts.seek(&Some(start_locator), Bias::Left);
5969        excerpts.prev();
5970
5971        let mut diff_transforms = self
5972            .diff_transforms
5973            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5974        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5975        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5976            diff_transforms.next();
5977        }
5978
5979        let excerpt = excerpts.item()?;
5980        Some(MultiBufferExcerpt {
5981            excerpt,
5982            offset: diff_transforms.start().output_dimension.0,
5983            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5984            excerpt_offset: excerpts.start().1,
5985            diff_transforms,
5986        })
5987    }
5988
5989    pub fn excerpt_boundaries_in_range<R, T>(
5990        &self,
5991        range: R,
5992    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5993    where
5994        R: RangeBounds<T>,
5995        T: ToOffset,
5996    {
5997        let start_offset;
5998        let start = match range.start_bound() {
5999            Bound::Included(start) => {
6000                start_offset = start.to_offset(self);
6001                Bound::Included(start_offset)
6002            }
6003            Bound::Excluded(_) => {
6004                panic!("not supported")
6005            }
6006            Bound::Unbounded => {
6007                start_offset = MultiBufferOffset::ZERO;
6008                Bound::Unbounded
6009            }
6010        };
6011        let end = match range.end_bound() {
6012            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6013            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6014            Bound::Unbounded => Bound::Unbounded,
6015        };
6016        let bounds = (start, end);
6017        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6018        cursor.seek(&DimensionPair {
6019            key: start_offset,
6020            value: None,
6021        });
6022
6023        if cursor
6024            .fetch_excerpt_with_range()
6025            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6026        {
6027            cursor.prev_excerpt();
6028        } else {
6029            cursor.seek_to_start_of_current_excerpt();
6030        }
6031        let mut prev_region = cursor
6032            .fetch_excerpt_with_range()
6033            .map(|(excerpt, _)| excerpt);
6034
6035        cursor.next_excerpt_forwards();
6036
6037        iter::from_fn(move || {
6038            loop {
6039                if self.singleton {
6040                    return None;
6041                }
6042
6043                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6044                cursor.next_excerpt_forwards();
6045                if !bounds.contains(&next_range.start.key) {
6046                    prev_region = Some(next_excerpt);
6047                    continue;
6048                }
6049
6050                let next_region_start = next_range.start.value.unwrap();
6051                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6052                    range.start.value.unwrap()
6053                } else {
6054                    self.max_point()
6055                };
6056
6057                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6058                    id: region.id,
6059                    buffer: region.buffer.clone(),
6060                    buffer_id: region.buffer_id,
6061                    range: region.range.clone(),
6062                    end_row: MultiBufferRow(next_region_start.row),
6063                });
6064
6065                let next = ExcerptInfo {
6066                    id: next_excerpt.id,
6067                    buffer: next_excerpt.buffer.clone(),
6068                    buffer_id: next_excerpt.buffer_id,
6069                    range: next_excerpt.range.clone(),
6070                    end_row: if next_excerpt.has_trailing_newline {
6071                        MultiBufferRow(next_region_end.row - 1)
6072                    } else {
6073                        MultiBufferRow(next_region_end.row)
6074                    },
6075                };
6076
6077                let row = MultiBufferRow(next_region_start.row);
6078
6079                prev_region = Some(next_excerpt);
6080
6081                return Some(ExcerptBoundary { row, prev, next });
6082            }
6083        })
6084    }
6085
6086    pub fn edit_count(&self) -> usize {
6087        self.edit_count
6088    }
6089
6090    pub fn non_text_state_update_count(&self) -> usize {
6091        self.non_text_state_update_count
6092    }
6093
6094    /// Returns the smallest enclosing bracket ranges containing the given range or
6095    /// None if no brackets contain range or the range is not contained in a single
6096    /// excerpt
6097    ///
6098    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6099    #[ztracing::instrument(skip_all)]
6100    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6101        &self,
6102        range: Range<T>,
6103        range_filter: Option<
6104            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6105        >,
6106    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6107        let range = range.start.to_offset(self)..range.end.to_offset(self);
6108        let mut excerpt = self.excerpt_containing(range.clone())?;
6109        let buffer = excerpt.buffer();
6110        let excerpt_buffer_range = excerpt.buffer_range();
6111
6112        // Filter to ranges contained in the excerpt
6113        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6114            excerpt_buffer_range.contains(&BufferOffset(open.start))
6115                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6116                && range_filter.is_none_or(|filter| {
6117                    filter(
6118                        buffer,
6119                        BufferOffset(open.start)..BufferOffset(close.end),
6120                        BufferOffset(close.start)..BufferOffset(close.end),
6121                    )
6122                })
6123        };
6124
6125        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6126            excerpt.map_range_to_buffer(range),
6127            Some(&range_filter),
6128        )?;
6129
6130        Some((
6131            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6132            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6133        ))
6134    }
6135
6136    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6137    /// not contained in a single excerpt
6138    pub fn enclosing_bracket_ranges<T: ToOffset>(
6139        &self,
6140        range: Range<T>,
6141    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6142    {
6143        let range = range.start.to_offset(self)..range.end.to_offset(self);
6144        let mut excerpt = self.excerpt_containing(range.clone())?;
6145
6146        Some(
6147            excerpt
6148                .buffer()
6149                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6150                .filter_map(move |pair| {
6151                    let open_range =
6152                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6153                    let close_range =
6154                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6155                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6156                        Some((
6157                            excerpt.map_range_from_buffer(open_range),
6158                            excerpt.map_range_from_buffer(close_range),
6159                        ))
6160                    } else {
6161                        None
6162                    }
6163                }),
6164        )
6165    }
6166
6167    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6168    /// not contained in a single excerpt
6169    pub fn text_object_ranges<T: ToOffset>(
6170        &self,
6171        range: Range<T>,
6172        options: TreeSitterOptions,
6173    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6174        let range = range.start.to_offset(self)..range.end.to_offset(self);
6175        self.excerpt_containing(range.clone())
6176            .map(|mut excerpt| {
6177                excerpt
6178                    .buffer()
6179                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6180                    .filter_map(move |(range, text_object)| {
6181                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6182                        if excerpt.contains_buffer_range(range.clone()) {
6183                            Some((excerpt.map_range_from_buffer(range), text_object))
6184                        } else {
6185                            None
6186                        }
6187                    })
6188            })
6189            .into_iter()
6190            .flatten()
6191    }
6192
6193    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6194    /// not contained in a single excerpt
6195    pub fn bracket_ranges<T: ToOffset>(
6196        &self,
6197        range: Range<T>,
6198    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6199    {
6200        let range = range.start.to_offset(self)..range.end.to_offset(self);
6201        let mut excerpt = self.excerpt_containing(range.clone())?;
6202        Some(
6203            excerpt
6204                .buffer()
6205                .bracket_ranges(excerpt.map_range_to_buffer(range))
6206                .filter_map(move |pair| {
6207                    let open_range =
6208                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6209                    let close_range =
6210                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6211                    excerpt
6212                        .contains_buffer_range(open_range.start..close_range.end)
6213                        .then(|| BracketMatch {
6214                            open_range: excerpt.map_range_from_buffer(open_range),
6215                            close_range: excerpt.map_range_from_buffer(close_range),
6216                            color_index: pair.color_index,
6217                            newline_only: pair.newline_only,
6218                            syntax_layer_depth: pair.syntax_layer_depth,
6219                        })
6220                })
6221                .map(BracketMatch::bracket_ranges),
6222        )
6223    }
6224
6225    pub fn redacted_ranges<'a, T: ToOffset>(
6226        &'a self,
6227        range: Range<T>,
6228        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6229    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6230        let range = range.start.to_offset(self)..range.end.to_offset(self);
6231        self.lift_buffer_metadata(range, move |buffer, range| {
6232            if redaction_enabled(buffer.file()) {
6233                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6234            } else {
6235                None
6236            }
6237        })
6238        .map(|(range, _, _)| range)
6239    }
6240
6241    pub fn runnable_ranges(
6242        &self,
6243        range: Range<Anchor>,
6244    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6245        let range = range.start.to_offset(self)..range.end.to_offset(self);
6246        self.lift_buffer_metadata(range, move |buffer, range| {
6247            Some(
6248                buffer
6249                    .runnable_ranges(range.clone())
6250                    .filter(move |runnable| {
6251                        runnable.run_range.start >= range.start
6252                            && runnable.run_range.end < range.end
6253                    })
6254                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6255            )
6256        })
6257        .map(|(run_range, runnable, _)| (run_range, runnable))
6258    }
6259
6260    pub fn line_indents(
6261        &self,
6262        start_row: MultiBufferRow,
6263        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6264    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6265        let max_point = self.max_point();
6266        let mut cursor = self.cursor::<Point, Point>();
6267        cursor.seek(&Point::new(start_row.0, 0));
6268        iter::from_fn(move || {
6269            let mut region = cursor.region()?;
6270            while !buffer_filter(&region.excerpt.buffer) {
6271                cursor.next();
6272                region = cursor.region()?;
6273            }
6274            let region = cursor.region()?;
6275            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6276            let buffer_start_row =
6277                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6278
6279            let buffer_end_row = if region.is_main_buffer
6280                && (region.has_trailing_newline || region.range.end == max_point)
6281            {
6282                region.buffer_range.end.row
6283            } else {
6284                region.buffer_range.end.row.saturating_sub(1)
6285            };
6286
6287            let line_indents = region
6288                .buffer
6289                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6290            let region_buffer_row = region.buffer_range.start.row;
6291            let region_row = region.range.start.row;
6292            let region_buffer = &region.excerpt.buffer;
6293            cursor.next();
6294            Some(line_indents.map(move |(buffer_row, indent)| {
6295                let row = region_row + (buffer_row - region_buffer_row);
6296                (MultiBufferRow(row), indent, region_buffer.as_ref())
6297            }))
6298        })
6299        .flatten()
6300    }
6301
6302    pub fn reversed_line_indents(
6303        &self,
6304        end_row: MultiBufferRow,
6305        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6306    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6307        let max_point = self.max_point();
6308        let mut cursor = self.cursor::<Point, Point>();
6309        cursor.seek(&Point::new(end_row.0, 0));
6310        iter::from_fn(move || {
6311            let mut region = cursor.region()?;
6312            while !buffer_filter(&region.excerpt.buffer) {
6313                cursor.prev();
6314                region = cursor.region()?;
6315            }
6316            let region = cursor.region()?;
6317
6318            let buffer_start_row = region.buffer_range.start.row;
6319            let buffer_end_row = if region.is_main_buffer
6320                && (region.has_trailing_newline || region.range.end == max_point)
6321            {
6322                region.buffer_range.end.row + 1
6323            } else {
6324                region.buffer_range.end.row
6325            };
6326
6327            let overshoot = end_row.0 - region.range.start.row;
6328            let buffer_end_row =
6329                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6330
6331            let line_indents = region
6332                .buffer
6333                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6334            let region_buffer_row = region.buffer_range.start.row;
6335            let region_row = region.range.start.row;
6336            let region_buffer = &region.excerpt.buffer;
6337            cursor.prev();
6338            Some(line_indents.map(move |(buffer_row, indent)| {
6339                let row = region_row + (buffer_row - region_buffer_row);
6340                (MultiBufferRow(row), indent, region_buffer.as_ref())
6341            }))
6342        })
6343        .flatten()
6344    }
6345
6346    pub async fn enclosing_indent(
6347        &self,
6348        mut target_row: MultiBufferRow,
6349    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6350        let max_row = MultiBufferRow(self.max_point().row);
6351        if target_row >= max_row {
6352            return None;
6353        }
6354
6355        let mut target_indent = self.line_indent_for_row(target_row);
6356
6357        // If the current row is at the start of an indented block, we want to return this
6358        // block as the enclosing indent.
6359        if !target_indent.is_line_empty() && target_row < max_row {
6360            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6361            if !next_line_indent.is_line_empty()
6362                && target_indent.raw_len() < next_line_indent.raw_len()
6363            {
6364                target_indent = next_line_indent;
6365                target_row.0 += 1;
6366            }
6367        }
6368
6369        const SEARCH_ROW_LIMIT: u32 = 25000;
6370        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6371        const YIELD_INTERVAL: u32 = 100;
6372
6373        let mut accessed_row_counter = 0;
6374
6375        // If there is a blank line at the current row, search for the next non indented lines
6376        if target_indent.is_line_empty() {
6377            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6378            let end =
6379                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6380
6381            let mut non_empty_line_above = None;
6382            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6383                if row < start {
6384                    break;
6385                }
6386                accessed_row_counter += 1;
6387                if accessed_row_counter == YIELD_INTERVAL {
6388                    accessed_row_counter = 0;
6389                    yield_now().await;
6390                }
6391                if !indent.is_line_empty() {
6392                    non_empty_line_above = Some((row, indent));
6393                    break;
6394                }
6395            }
6396
6397            let mut non_empty_line_below = None;
6398            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6399                if row > end {
6400                    break;
6401                }
6402                accessed_row_counter += 1;
6403                if accessed_row_counter == YIELD_INTERVAL {
6404                    accessed_row_counter = 0;
6405                    yield_now().await;
6406                }
6407                if !indent.is_line_empty() {
6408                    non_empty_line_below = Some((row, indent));
6409                    break;
6410                }
6411            }
6412
6413            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6414                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6415                    if above_indent.raw_len() >= below_indent.raw_len() {
6416                        (above_row, above_indent)
6417                    } else {
6418                        (below_row, below_indent)
6419                    }
6420                }
6421                (Some(above), None) => above,
6422                (None, Some(below)) => below,
6423                _ => return None,
6424            };
6425
6426            target_indent = indent;
6427            target_row = row;
6428        }
6429
6430        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6431        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6432
6433        let mut start_indent = None;
6434        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6435            if row < start {
6436                break;
6437            }
6438            accessed_row_counter += 1;
6439            if accessed_row_counter == YIELD_INTERVAL {
6440                accessed_row_counter = 0;
6441                yield_now().await;
6442            }
6443            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6444                start_indent = Some((row, indent));
6445                break;
6446            }
6447        }
6448        let (start_row, start_indent_size) = start_indent?;
6449
6450        let mut end_indent = (end, None);
6451        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6452            if row > end {
6453                break;
6454            }
6455            accessed_row_counter += 1;
6456            if accessed_row_counter == YIELD_INTERVAL {
6457                accessed_row_counter = 0;
6458                yield_now().await;
6459            }
6460            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6461                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6462                break;
6463            }
6464        }
6465        let (end_row, end_indent_size) = end_indent;
6466
6467        let indent = if let Some(end_indent_size) = end_indent_size {
6468            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6469                start_indent_size
6470            } else {
6471                end_indent_size
6472            }
6473        } else {
6474            start_indent_size
6475        };
6476
6477        Some((start_row..end_row, indent))
6478    }
6479
6480    pub fn indent_guides_in_range<T: ToPoint>(
6481        &self,
6482        range: Range<T>,
6483        ignore_disabled_for_language: bool,
6484        cx: &App,
6485    ) -> impl Iterator<Item = IndentGuide> {
6486        let range = range.start.to_point(self)..range.end.to_point(self);
6487        let start_row = MultiBufferRow(range.start.row);
6488        let end_row = MultiBufferRow(range.end.row);
6489
6490        let mut row_indents = self.line_indents(start_row, |buffer| {
6491            let settings =
6492                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6493            settings.indent_guides.enabled || ignore_disabled_for_language
6494        });
6495
6496        let mut result = Vec::new();
6497        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6498
6499        let mut prev_settings = None;
6500        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6501            if first_row > end_row {
6502                break;
6503            }
6504            let current_depth = indent_stack.len() as u32;
6505
6506            // Avoid retrieving the language settings repeatedly for every buffer row.
6507            if let Some((prev_buffer_id, _)) = &prev_settings
6508                && prev_buffer_id != &buffer.remote_id()
6509            {
6510                prev_settings.take();
6511            }
6512            let settings = &prev_settings
6513                .get_or_insert_with(|| {
6514                    (
6515                        buffer.remote_id(),
6516                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6517                    )
6518                })
6519                .1;
6520            let tab_size = settings.tab_size.get();
6521
6522            // When encountering empty, continue until found useful line indent
6523            // then add to the indent stack with the depth found
6524            let mut found_indent = false;
6525            let mut last_row = first_row;
6526            if line_indent.is_line_blank() {
6527                while !found_indent {
6528                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6529                        break;
6530                    };
6531                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6532                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6533                        break;
6534                    }
6535
6536                    if new_line_indent.is_line_blank() {
6537                        continue;
6538                    }
6539                    last_row = target_row.min(end_row);
6540                    line_indent = new_line_indent;
6541                    found_indent = true;
6542                    break;
6543                }
6544            } else {
6545                found_indent = true
6546            }
6547
6548            let depth = if found_indent {
6549                line_indent.len(tab_size) / tab_size
6550            } else {
6551                0
6552            };
6553
6554            match depth.cmp(&current_depth) {
6555                cmp::Ordering::Less => {
6556                    for _ in 0..(current_depth - depth) {
6557                        let mut indent = indent_stack.pop().unwrap();
6558                        if last_row != first_row {
6559                            // In this case, we landed on an empty row, had to seek forward,
6560                            // and discovered that the indent we where on is ending.
6561                            // This means that the last display row must
6562                            // be on line that ends this indent range, so we
6563                            // should display the range up to the first non-empty line
6564                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6565                        }
6566
6567                        result.push(indent)
6568                    }
6569                }
6570                cmp::Ordering::Greater => {
6571                    for next_depth in current_depth..depth {
6572                        indent_stack.push(IndentGuide {
6573                            buffer_id: buffer.remote_id(),
6574                            start_row: first_row,
6575                            end_row: last_row,
6576                            depth: next_depth,
6577                            tab_size,
6578                            settings: settings.indent_guides.clone(),
6579                        });
6580                    }
6581                }
6582                _ => {}
6583            }
6584
6585            for indent in indent_stack.iter_mut() {
6586                indent.end_row = last_row;
6587            }
6588        }
6589
6590        result.extend(indent_stack);
6591        result.into_iter()
6592    }
6593
6594    pub fn trailing_excerpt_update_count(&self) -> usize {
6595        self.trailing_excerpt_update_count
6596    }
6597
6598    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6599        self.point_to_buffer_offset(point)
6600            .and_then(|(buffer, _)| buffer.file())
6601    }
6602
6603    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6604        self.point_to_buffer_offset(offset)
6605            .and_then(|(buffer, offset)| buffer.language_at(offset))
6606    }
6607
6608    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6609        self.excerpts
6610            .first()
6611            .map(|excerpt| &excerpt.buffer)
6612            .map(|buffer| {
6613                language_settings(
6614                    buffer.language().map(|language| language.name()),
6615                    buffer.file(),
6616                    cx,
6617                )
6618            })
6619            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6620    }
6621
6622    pub fn language_settings_at<'a, T: ToOffset>(
6623        &'a self,
6624        point: T,
6625        cx: &'a App,
6626    ) -> Cow<'a, LanguageSettings> {
6627        let mut language = None;
6628        let mut file = None;
6629        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6630            language = buffer.language_at(offset);
6631            file = buffer.file();
6632        }
6633        language_settings(language.map(|l| l.name()), file, cx)
6634    }
6635
6636    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6637        self.point_to_buffer_offset(point)
6638            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6639    }
6640
6641    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6642        self.point_to_buffer_offset(point)
6643            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6644            .unwrap_or_default()
6645    }
6646
6647    pub fn language_indent_size_at<T: ToOffset>(
6648        &self,
6649        position: T,
6650        cx: &App,
6651    ) -> Option<IndentSize> {
6652        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6653        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6654    }
6655
6656    pub fn is_dirty(&self) -> bool {
6657        self.is_dirty
6658    }
6659
6660    pub fn has_deleted_file(&self) -> bool {
6661        self.has_deleted_file
6662    }
6663
6664    pub fn has_conflict(&self) -> bool {
6665        self.has_conflict
6666    }
6667
6668    pub fn has_diagnostics(&self) -> bool {
6669        self.excerpts
6670            .iter()
6671            .any(|excerpt| excerpt.buffer.has_diagnostics())
6672    }
6673
6674    pub fn diagnostic_group(
6675        &self,
6676        buffer_id: BufferId,
6677        group_id: usize,
6678    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6679        self.lift_buffer_metadata::<Point, _, _>(
6680            Point::zero()..self.max_point(),
6681            move |buffer, range| {
6682                if buffer.remote_id() != buffer_id {
6683                    return None;
6684                };
6685                Some(
6686                    buffer
6687                        .diagnostics_in_range(range, false)
6688                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6689                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6690                )
6691            },
6692        )
6693        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6694    }
6695
6696    pub fn diagnostics_in_range<'a, MBD>(
6697        &'a self,
6698        range: Range<MBD>,
6699    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6700    where
6701        MBD::TextDimension: 'a
6702            + text::ToOffset
6703            + text::FromAnchor
6704            + Sub<Output = MBD::TextDimension>
6705            + fmt::Debug
6706            + ops::Add<Output = MBD::TextDimension>
6707            + ops::AddAssign
6708            + Ord,
6709        MBD: MultiBufferDimension
6710            + Ord
6711            + Sub<Output = MBD::TextDimension>
6712            + ops::Add<MBD::TextDimension, Output = MBD>
6713            + ops::AddAssign<MBD::TextDimension>
6714            + 'a,
6715    {
6716        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6717            Some(
6718                buffer
6719                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6720                    .map(|entry| (entry.range, entry.diagnostic)),
6721            )
6722        })
6723        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6724    }
6725
6726    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6727        &'a self,
6728        range: Range<MBD>,
6729    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6730    where
6731        MBD: MultiBufferDimension
6732            + Ord
6733            + Sub<Output = MBD::TextDimension>
6734            + ops::Add<MBD::TextDimension, Output = MBD>
6735            + ops::AddAssign<MBD::TextDimension>,
6736        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6737            + ops::Add<Output = MBD::TextDimension>
6738            + text::ToOffset
6739            + text::FromAnchor
6740            + AddAssign<MBD::TextDimension>
6741            + Ord,
6742    {
6743        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6744            Some(
6745                buffer
6746                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6747                    .map(|entry| (entry.range, entry.diagnostic)),
6748            )
6749        })
6750        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6751    }
6752
6753    pub fn syntax_ancestor<T: ToOffset>(
6754        &self,
6755        range: Range<T>,
6756    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6757        let range = range.start.to_offset(self)..range.end.to_offset(self);
6758        let mut excerpt = self.excerpt_containing(range.clone())?;
6759        let node = excerpt
6760            .buffer()
6761            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6762        let node_range = node.byte_range();
6763        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6764        if !excerpt.contains_buffer_range(node_range.clone()) {
6765            return None;
6766        };
6767        Some((node, excerpt.map_range_from_buffer(node_range)))
6768    }
6769
6770    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6771        let (excerpt_id, _, buffer) = self.as_singleton()?;
6772        let outline = buffer.outline(theme);
6773        Some(Outline::new(
6774            outline
6775                .items
6776                .into_iter()
6777                .flat_map(|item| {
6778                    Some(OutlineItem {
6779                        depth: item.depth,
6780                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6781                        source_range_for_text: self
6782                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6783                        text: item.text,
6784                        highlight_ranges: item.highlight_ranges,
6785                        name_ranges: item.name_ranges,
6786                        body_range: item.body_range.and_then(|body_range| {
6787                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6788                        }),
6789                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6790                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6791                        }),
6792                    })
6793                })
6794                .collect(),
6795        ))
6796    }
6797
6798    pub fn symbols_containing<T: ToOffset>(
6799        &self,
6800        offset: T,
6801        theme: Option<&SyntaxTheme>,
6802    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6803        let anchor = self.anchor_before(offset);
6804        let excerpt @ &Excerpt {
6805            id: excerpt_id,
6806            buffer_id,
6807            ref buffer,
6808            ..
6809        } = self.excerpt(anchor.excerpt_id)?;
6810        if cfg!(debug_assertions) {
6811            match anchor.text_anchor.buffer_id {
6812                // we clearly are hitting this according to sentry, but in what situations can this occur?
6813                Some(anchor_buffer_id) => {
6814                    assert_eq!(
6815                        anchor_buffer_id, buffer_id,
6816                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6817                    )
6818                }
6819                None => assert!(anchor.is_max()),
6820            }
6821        };
6822        Some((
6823            buffer_id,
6824            buffer
6825                .symbols_containing(anchor.text_anchor, theme)
6826                .into_iter()
6827                .flat_map(|item| {
6828                    Some(OutlineItem {
6829                        depth: item.depth,
6830                        source_range_for_text: Anchor::range_in_buffer(
6831                            excerpt_id,
6832                            item.source_range_for_text,
6833                        ),
6834                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6835                        text: item.text,
6836                        highlight_ranges: item.highlight_ranges,
6837                        name_ranges: item.name_ranges,
6838                        body_range: item
6839                            .body_range
6840                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6841                        annotation_range: item
6842                            .annotation_range
6843                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6844                    })
6845                })
6846                .collect(),
6847        ))
6848    }
6849
6850    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6851        if id == ExcerptId::min() {
6852            Locator::min_ref()
6853        } else if id == ExcerptId::max() {
6854            Locator::max_ref()
6855        } else {
6856            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6857            if let Some(entry) = item
6858                && entry.id == id
6859            {
6860                return &entry.locator;
6861            }
6862            panic!("invalid excerpt id {id:?}")
6863        }
6864    }
6865
6866    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6867    fn excerpt_locators_for_ids(
6868        &self,
6869        ids: impl IntoIterator<Item = ExcerptId>,
6870    ) -> SmallVec<[Locator; 1]> {
6871        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6872        sorted_ids.sort_unstable();
6873        sorted_ids.dedup();
6874        let mut locators = SmallVec::new();
6875
6876        while sorted_ids.last() == Some(&ExcerptId::max()) {
6877            sorted_ids.pop();
6878            locators.push(Locator::max());
6879        }
6880
6881        let mut sorted_ids = sorted_ids.into_iter().peekable();
6882        locators.extend(
6883            sorted_ids
6884                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6885                .map(|_| Locator::min()),
6886        );
6887
6888        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6889        for id in sorted_ids {
6890            if cursor.seek_forward(&id, Bias::Left) {
6891                locators.push(cursor.item().unwrap().locator.clone());
6892            } else {
6893                panic!("invalid excerpt id {:?}", id);
6894            }
6895        }
6896
6897        locators.sort_unstable();
6898        locators
6899    }
6900
6901    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6902        Some(self.excerpt(excerpt_id)?.buffer_id)
6903    }
6904
6905    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6906        Some(&self.excerpt(excerpt_id)?.buffer)
6907    }
6908
6909    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6910        let mut cursor = self
6911            .excerpts
6912            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6913        let locator = self.excerpt_locator_for_id(excerpt_id);
6914        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6915        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6916            sought_exact = true;
6917            cursor.prev();
6918        } else if excerpt_id == ExcerptId::min() {
6919            sought_exact = true;
6920        }
6921        if sought_exact {
6922            let start = cursor.start().1;
6923            let end = cursor.end().1;
6924            let mut diff_transforms = self
6925                .diff_transforms
6926                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6927            diff_transforms.seek(&start, Bias::Left);
6928            let overshoot = start - diff_transforms.start().0;
6929            let start = diff_transforms.start().1 + overshoot;
6930            diff_transforms.seek(&end, Bias::Right);
6931            let overshoot = end - diff_transforms.start().0;
6932            let end = diff_transforms.start().1 + overshoot;
6933            Some(start.0..end.0)
6934        } else {
6935            None
6936        }
6937    }
6938
6939    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6940    /// to have the latest excerpt id for the one passed in and will also remap
6941    /// `ExcerptId::max()` to the corresponding excertp ID.
6942    ///
6943    /// Callers of this function should generally use the resulting excerpt's `id` field
6944    /// afterwards.
6945    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6946        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6947        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6948        let locator = self.excerpt_locator_for_id(excerpt_id);
6949        cursor.seek(&Some(locator), Bias::Left);
6950        if let Some(excerpt) = cursor.item()
6951            && excerpt.id == excerpt_id
6952        {
6953            return Some(excerpt);
6954        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6955            cursor.prev();
6956            return cursor.item();
6957        }
6958        None
6959    }
6960
6961    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6962    pub fn excerpt_containing<T: ToOffset>(
6963        &self,
6964        range: Range<T>,
6965    ) -> Option<MultiBufferExcerpt<'_>> {
6966        let range = range.start.to_offset(self)..range.end.to_offset(self);
6967        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6968        cursor.seek(&range.start);
6969
6970        let start_excerpt = cursor.excerpt()?;
6971        if range.end != range.start {
6972            cursor.seek_forward(&range.end);
6973            if cursor.excerpt()?.id != start_excerpt.id {
6974                return None;
6975            }
6976        }
6977
6978        cursor.seek_to_start_of_current_excerpt();
6979        let region = cursor.region()?;
6980        let offset = region.range.start;
6981        let buffer_offset = start_excerpt.buffer_start_offset();
6982        let excerpt_offset = *cursor.excerpts.start();
6983        Some(MultiBufferExcerpt {
6984            diff_transforms: cursor.diff_transforms,
6985            excerpt: start_excerpt,
6986            offset,
6987            buffer_offset,
6988            excerpt_offset,
6989        })
6990    }
6991
6992    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6993        if let Some(id) = anchor.text_anchor.buffer_id {
6994            return Some(id);
6995        }
6996        let excerpt = self.excerpt_containing(anchor..anchor)?;
6997        Some(excerpt.buffer_id())
6998    }
6999
7000    pub fn selections_in_range<'a>(
7001        &'a self,
7002        range: &'a Range<Anchor>,
7003        include_local: bool,
7004    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7005        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7006        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7007        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7008        cursor.seek(start_locator, Bias::Left);
7009        cursor
7010            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7011            .flat_map(move |excerpt| {
7012                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7013                if excerpt.id == range.start.excerpt_id {
7014                    query_range.start = range.start.text_anchor;
7015                }
7016                if excerpt.id == range.end.excerpt_id {
7017                    query_range.end = range.end.text_anchor;
7018                }
7019
7020                excerpt
7021                    .buffer
7022                    .selections_in_range(query_range, include_local)
7023                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7024                        selections.map(move |selection| {
7025                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7026                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7027                            if range.start.cmp(&start, self).is_gt() {
7028                                start = range.start;
7029                            }
7030                            if range.end.cmp(&end, self).is_lt() {
7031                                end = range.end;
7032                            }
7033
7034                            (
7035                                replica_id,
7036                                line_mode,
7037                                cursor_shape,
7038                                Selection {
7039                                    id: selection.id,
7040                                    start,
7041                                    end,
7042                                    reversed: selection.reversed,
7043                                    goal: selection.goal,
7044                                },
7045                            )
7046                        })
7047                    })
7048            })
7049    }
7050
7051    pub fn show_headers(&self) -> bool {
7052        self.show_headers
7053    }
7054
7055    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7056        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7057    }
7058
7059    pub fn all_diff_hunks_expanded(&self) -> bool {
7060        self.all_diff_hunks_expanded
7061    }
7062
7063    /// Visually annotates a position or range with the `Debug` representation of a value. The
7064    /// callsite of this function is used as a key - previous annotations will be removed.
7065    #[cfg(debug_assertions)]
7066    #[track_caller]
7067    pub fn debug<V, R>(&self, ranges: &R, value: V)
7068    where
7069        R: debug::ToMultiBufferDebugRanges,
7070        V: std::fmt::Debug,
7071    {
7072        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7073    }
7074
7075    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7076    /// debug annotations with the same key will be removed. The key is also used to determine the
7077    /// annotation's color.
7078    #[cfg(debug_assertions)]
7079    #[track_caller]
7080    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7081    where
7082        K: std::hash::Hash + 'static,
7083        R: debug::ToMultiBufferDebugRanges,
7084        V: std::fmt::Debug,
7085    {
7086        let text_ranges = ranges
7087            .to_multi_buffer_debug_ranges(self)
7088            .into_iter()
7089            .flat_map(|range| {
7090                self.range_to_buffer_ranges(range.start..=range.end)
7091                    .into_iter()
7092                    .map(|(buffer, range, _excerpt_id)| {
7093                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7094                    })
7095            })
7096            .collect();
7097        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7098            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7099        });
7100    }
7101
7102    fn excerpt_edits_for_diff_change(
7103        &self,
7104        buffer_state: &BufferState,
7105        diff_change_range: Range<usize>,
7106    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7107        let mut excerpt_edits = Vec::new();
7108        for locator in &buffer_state.excerpts {
7109            let mut cursor = self
7110                .excerpts
7111                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7112            cursor.seek_forward(&Some(locator), Bias::Left);
7113            if let Some(excerpt) = cursor.item()
7114                && excerpt.locator == *locator
7115            {
7116                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7117                if diff_change_range.end < excerpt_buffer_range.start
7118                    || diff_change_range.start > excerpt_buffer_range.end
7119                {
7120                    continue;
7121                }
7122                let excerpt_start = cursor.start().1;
7123                let excerpt_len = excerpt.text_summary.len;
7124                let diff_change_start_in_excerpt = diff_change_range
7125                    .start
7126                    .saturating_sub(excerpt_buffer_range.start);
7127                let diff_change_end_in_excerpt = diff_change_range
7128                    .end
7129                    .saturating_sub(excerpt_buffer_range.start);
7130                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7131                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7132                excerpt_edits.push(Edit {
7133                    old: edit_start..edit_end,
7134                    new: edit_start..edit_end,
7135                });
7136            }
7137        }
7138        excerpt_edits
7139    }
7140}
7141
7142#[cfg(any(test, feature = "test-support"))]
7143impl MultiBufferSnapshot {
7144    pub fn random_byte_range(
7145        &self,
7146        start_offset: MultiBufferOffset,
7147        rng: &mut impl rand::Rng,
7148    ) -> Range<MultiBufferOffset> {
7149        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7150        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7151        start..end
7152    }
7153
7154    #[cfg(any(test, feature = "test-support"))]
7155    fn check_invariants(&self) {
7156        let excerpts = self.excerpts.items(());
7157        let excerpt_ids = self.excerpt_ids.items(());
7158
7159        for (ix, excerpt) in excerpts.iter().enumerate() {
7160            if ix == 0 {
7161                if excerpt.locator <= Locator::min() {
7162                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7163                }
7164            } else if excerpt.locator <= excerpts[ix - 1].locator {
7165                panic!("excerpts are out-of-order: {:?}", excerpts);
7166            }
7167        }
7168
7169        for (ix, entry) in excerpt_ids.iter().enumerate() {
7170            if ix == 0 {
7171                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7172                    panic!("invalid first excerpt id {:?}", entry.id);
7173                }
7174            } else if entry.id <= excerpt_ids[ix - 1].id {
7175                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7176            }
7177        }
7178
7179        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7180            panic!(
7181                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7182                self.excerpts.summary().text,
7183                self.diff_transforms.summary().input,
7184                self.diff_transforms.items(()),
7185            );
7186        }
7187
7188        let mut prev_transform: Option<&DiffTransform> = None;
7189        for item in self.diff_transforms.iter() {
7190            if let DiffTransform::BufferContent {
7191                summary,
7192                inserted_hunk_info,
7193            } = item
7194            {
7195                if let Some(DiffTransform::BufferContent {
7196                    inserted_hunk_info: prev_inserted_hunk_info,
7197                    ..
7198                }) = prev_transform
7199                    && *inserted_hunk_info == *prev_inserted_hunk_info
7200                {
7201                    panic!(
7202                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7203                        self.diff_transforms.items(())
7204                    );
7205                }
7206                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7207                    panic!("empty buffer content transform");
7208                }
7209            }
7210            prev_transform = Some(item);
7211        }
7212    }
7213}
7214
7215impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7216where
7217    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7218    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7219{
7220    #[instrument(skip_all)]
7221    fn seek(&mut self, position: &MBD) {
7222        let position = OutputDimension(*position);
7223        self.cached_region.take();
7224        self.diff_transforms.seek(&position, Bias::Right);
7225        if self.diff_transforms.item().is_none()
7226            && self.diff_transforms.start().output_dimension == position
7227        {
7228            self.diff_transforms.prev();
7229        }
7230
7231        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7232        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7233            let overshoot = position - self.diff_transforms.start().output_dimension;
7234            excerpt_position += overshoot;
7235        }
7236
7237        self.excerpts.seek(&excerpt_position, Bias::Right);
7238        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7239            self.excerpts.prev();
7240        }
7241    }
7242
7243    fn seek_forward(&mut self, position: &MBD) {
7244        let position = OutputDimension(*position);
7245        self.cached_region.take();
7246        self.diff_transforms.seek_forward(&position, Bias::Right);
7247        if self.diff_transforms.item().is_none()
7248            && self.diff_transforms.start().output_dimension == position
7249        {
7250            self.diff_transforms.prev();
7251        }
7252
7253        let overshoot = position - self.diff_transforms.start().output_dimension;
7254        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7255        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7256            excerpt_position += overshoot;
7257        }
7258
7259        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7260        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7261            self.excerpts.prev();
7262        }
7263    }
7264
7265    fn next_excerpt(&mut self) {
7266        self.excerpts.next();
7267        self.seek_to_start_of_current_excerpt();
7268    }
7269
7270    fn prev_excerpt(&mut self) {
7271        self.excerpts.prev();
7272        self.seek_to_start_of_current_excerpt();
7273    }
7274
7275    fn seek_to_start_of_current_excerpt(&mut self) {
7276        self.cached_region.take();
7277
7278        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7279            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7280            && self.diff_transforms.next_item().is_some()
7281        {
7282            self.diff_transforms.next();
7283        }
7284    }
7285
7286    fn next_excerpt_forwards(&mut self) {
7287        self.excerpts.next();
7288        self.seek_to_start_of_current_excerpt_forward();
7289    }
7290
7291    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7292        self.cached_region.take();
7293
7294        if self
7295            .diff_transforms
7296            .seek_forward(self.excerpts.start(), Bias::Left)
7297            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7298            && self.diff_transforms.next_item().is_some()
7299        {
7300            self.diff_transforms.next();
7301        }
7302    }
7303
7304    fn next(&mut self) {
7305        self.cached_region.take();
7306        match self
7307            .diff_transforms
7308            .end()
7309            .excerpt_dimension
7310            .cmp(&self.excerpts.end())
7311        {
7312            cmp::Ordering::Less => self.diff_transforms.next(),
7313            cmp::Ordering::Greater => self.excerpts.next(),
7314            cmp::Ordering::Equal => {
7315                self.diff_transforms.next();
7316                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7317                    || self.diff_transforms.item().is_none()
7318                {
7319                    self.excerpts.next();
7320                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7321                    self.diff_transforms.item()
7322                    && self
7323                        .excerpts
7324                        .item()
7325                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7326                {
7327                    self.excerpts.next();
7328                }
7329            }
7330        }
7331    }
7332
7333    fn prev(&mut self) {
7334        self.cached_region.take();
7335        match self
7336            .diff_transforms
7337            .start()
7338            .excerpt_dimension
7339            .cmp(self.excerpts.start())
7340        {
7341            cmp::Ordering::Less => self.excerpts.prev(),
7342            cmp::Ordering::Greater => self.diff_transforms.prev(),
7343            cmp::Ordering::Equal => {
7344                self.diff_transforms.prev();
7345                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7346                    || self.diff_transforms.item().is_none()
7347                {
7348                    self.excerpts.prev();
7349                }
7350            }
7351        }
7352    }
7353
7354    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7355        self.cached_region
7356            .get_or_init(|| self.build_region())
7357            .as_ref()
7358    }
7359
7360    fn is_at_start_of_excerpt(&mut self) -> bool {
7361        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7362            return false;
7363        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7364            return true;
7365        }
7366
7367        self.diff_transforms.prev();
7368        let prev_transform = self.diff_transforms.item();
7369        self.diff_transforms.next();
7370
7371        prev_transform.is_none_or(|next_transform| {
7372            matches!(next_transform, DiffTransform::BufferContent { .. })
7373        })
7374    }
7375
7376    fn is_at_end_of_excerpt(&self) -> bool {
7377        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7378            return false;
7379        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7380            || self.diff_transforms.item().is_none()
7381        {
7382            return true;
7383        }
7384
7385        let next_transform = self.diff_transforms.next_item();
7386        next_transform.is_none_or(|next_transform| match next_transform {
7387            DiffTransform::BufferContent { .. } => true,
7388            DiffTransform::DeletedHunk { hunk_info, .. } => self
7389                .excerpts
7390                .item()
7391                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7392        })
7393    }
7394
7395    fn main_buffer_position(&self) -> Option<BD> {
7396        let excerpt = self.excerpts.item()?;
7397        let buffer = &excerpt.buffer;
7398        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7399        let mut buffer_start = buffer_context_start;
7400        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7401        buffer_start += overshoot;
7402        Some(buffer_start)
7403    }
7404
7405    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7406        let excerpt = self.excerpts.item()?;
7407        match self.diff_transforms.item()? {
7408            DiffTransform::DeletedHunk {
7409                buffer_id,
7410                base_text_byte_range,
7411                has_trailing_newline,
7412                hunk_info,
7413                ..
7414            } => {
7415                let diff = self.diffs.get(buffer_id)?;
7416                let buffer = diff.base_text();
7417                let mut rope_cursor = buffer.as_rope().cursor(0);
7418                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7419                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7420                let mut buffer_end = buffer_start;
7421                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7422                let start = self.diff_transforms.start().output_dimension.0;
7423                let end = self.diff_transforms.end().output_dimension.0;
7424                Some(MultiBufferRegion {
7425                    buffer,
7426                    excerpt,
7427                    has_trailing_newline: *has_trailing_newline,
7428                    is_main_buffer: false,
7429                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7430                        hunk_info.hunk_secondary_status,
7431                    )),
7432                    buffer_range: buffer_start..buffer_end,
7433                    range: start..end,
7434                })
7435            }
7436            DiffTransform::BufferContent {
7437                inserted_hunk_info, ..
7438            } => {
7439                let buffer = &excerpt.buffer;
7440                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7441
7442                let mut start = self.diff_transforms.start().output_dimension.0;
7443                let mut buffer_start = buffer_context_start;
7444                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7445                    let overshoot =
7446                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7447                    start += overshoot;
7448                } else {
7449                    let overshoot =
7450                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7451                    buffer_start += overshoot;
7452                }
7453
7454                let mut end;
7455                let mut buffer_end;
7456                let has_trailing_newline;
7457                let transform_end = self.diff_transforms.end();
7458                if transform_end.excerpt_dimension < self.excerpts.end() {
7459                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7460                    end = transform_end.output_dimension.0;
7461                    buffer_end = buffer_context_start;
7462                    buffer_end += overshoot;
7463                    has_trailing_newline = false;
7464                } else {
7465                    let overshoot =
7466                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7467                    end = self.diff_transforms.start().output_dimension.0;
7468                    end += overshoot;
7469                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7470                    has_trailing_newline = excerpt.has_trailing_newline;
7471                };
7472
7473                let diff_hunk_status = inserted_hunk_info.map(|info| {
7474                    if info.is_logically_deleted {
7475                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7476                    } else {
7477                        DiffHunkStatus::added(info.hunk_secondary_status)
7478                    }
7479                });
7480
7481                Some(MultiBufferRegion {
7482                    buffer,
7483                    excerpt,
7484                    has_trailing_newline,
7485                    is_main_buffer: true,
7486                    diff_hunk_status,
7487                    buffer_range: buffer_start..buffer_end,
7488                    range: start..end,
7489                })
7490            }
7491        }
7492    }
7493
7494    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7495        let excerpt = self.excerpts.item()?;
7496        match self.diff_transforms.item()? {
7497            &DiffTransform::DeletedHunk { .. } => {
7498                let start = self.diff_transforms.start().output_dimension.0;
7499                let end = self.diff_transforms.end().output_dimension.0;
7500                Some((excerpt, start..end))
7501            }
7502            DiffTransform::BufferContent { .. } => {
7503                let mut start = self.diff_transforms.start().output_dimension.0;
7504                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7505                    let overshoot =
7506                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7507                    start += overshoot;
7508                }
7509
7510                let mut end;
7511                let transform_end = self.diff_transforms.end();
7512                if transform_end.excerpt_dimension < self.excerpts.end() {
7513                    end = transform_end.output_dimension.0;
7514                } else {
7515                    let overshoot =
7516                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7517                    end = self.diff_transforms.start().output_dimension.0;
7518                    end += overshoot;
7519                };
7520
7521                Some((excerpt, start..end))
7522            }
7523        }
7524    }
7525
7526    fn excerpt(&self) -> Option<&'a Excerpt> {
7527        self.excerpts.item()
7528    }
7529}
7530
7531impl Excerpt {
7532    fn new(
7533        id: ExcerptId,
7534        locator: Locator,
7535        buffer_id: BufferId,
7536        buffer: Arc<BufferSnapshot>,
7537        range: ExcerptRange<text::Anchor>,
7538        has_trailing_newline: bool,
7539    ) -> Self {
7540        Excerpt {
7541            id,
7542            locator,
7543            max_buffer_row: range.context.end.to_point(&buffer).row,
7544            text_summary: buffer
7545                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7546            buffer_id,
7547            buffer,
7548            range,
7549            has_trailing_newline,
7550        }
7551    }
7552
7553    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7554        let content_start = self.range.context.start.to_offset(&self.buffer);
7555        let chunks_start = content_start + range.start;
7556        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7557
7558        let has_footer = self.has_trailing_newline
7559            && range.start <= self.text_summary.len
7560            && range.end > self.text_summary.len;
7561
7562        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7563
7564        ExcerptChunks {
7565            excerpt_id: self.id,
7566            content_chunks,
7567            has_footer,
7568        }
7569    }
7570
7571    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7572        let content_start = self.range.context.start.to_offset(&self.buffer);
7573        let chunks_start = content_start + range.start;
7574        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7575        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7576        excerpt_chunks.has_footer = self.has_trailing_newline
7577            && range.start <= self.text_summary.len
7578            && range.end > self.text_summary.len;
7579    }
7580
7581    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7582        if text_anchor
7583            .cmp(&self.range.context.start, &self.buffer)
7584            .is_lt()
7585        {
7586            self.range.context.start
7587        } else if text_anchor
7588            .cmp(&self.range.context.end, &self.buffer)
7589            .is_gt()
7590        {
7591            self.range.context.end
7592        } else {
7593            text_anchor
7594        }
7595    }
7596
7597    fn contains(&self, anchor: &Anchor) -> bool {
7598        (anchor.text_anchor.buffer_id == None
7599            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7600            && self
7601                .range
7602                .context
7603                .start
7604                .cmp(&anchor.text_anchor, &self.buffer)
7605                .is_le()
7606            && self
7607                .range
7608                .context
7609                .end
7610                .cmp(&anchor.text_anchor, &self.buffer)
7611                .is_ge()
7612    }
7613
7614    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7615    fn buffer_start_offset(&self) -> BufferOffset {
7616        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7617    }
7618
7619    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7620    fn buffer_end_offset(&self) -> BufferOffset {
7621        self.buffer_start_offset() + self.text_summary.len
7622    }
7623}
7624
7625impl<'a> MultiBufferExcerpt<'a> {
7626    pub fn id(&self) -> ExcerptId {
7627        self.excerpt.id
7628    }
7629
7630    pub fn buffer_id(&self) -> BufferId {
7631        self.excerpt.buffer_id
7632    }
7633
7634    pub fn start_anchor(&self) -> Anchor {
7635        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7636    }
7637
7638    pub fn end_anchor(&self) -> Anchor {
7639        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7640    }
7641
7642    pub fn buffer(&self) -> &'a BufferSnapshot {
7643        &self.excerpt.buffer
7644    }
7645
7646    pub fn buffer_range(&self) -> Range<BufferOffset> {
7647        self.buffer_offset
7648            ..BufferOffset(
7649                self.excerpt
7650                    .range
7651                    .context
7652                    .end
7653                    .to_offset(&self.excerpt.buffer.text),
7654            )
7655    }
7656
7657    pub fn start_offset(&self) -> MultiBufferOffset {
7658        self.offset
7659    }
7660
7661    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7662    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7663        self.map_range_to_buffer(offset..offset).start
7664    }
7665
7666    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7667    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7668        self.diff_transforms
7669            .seek(&OutputDimension(range.start), Bias::Right);
7670        let start = self.map_offset_to_buffer_internal(range.start);
7671        let end = if range.end > range.start {
7672            self.diff_transforms
7673                .seek_forward(&OutputDimension(range.end), Bias::Right);
7674            self.map_offset_to_buffer_internal(range.end)
7675        } else {
7676            start
7677        };
7678        start..end
7679    }
7680
7681    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7682        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7683        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7684            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7685        };
7686        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7687        self.buffer_offset + offset_in_excerpt
7688    }
7689
7690    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7691    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7692        self.map_range_from_buffer(buffer_offset..buffer_offset)
7693            .start
7694    }
7695
7696    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7697    pub fn map_range_from_buffer(
7698        &mut self,
7699        buffer_range: Range<BufferOffset>,
7700    ) -> Range<MultiBufferOffset> {
7701        if buffer_range.start < self.buffer_offset {
7702            log::warn!(
7703                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7704            );
7705            return self.offset..self.offset;
7706        }
7707        let overshoot = buffer_range.start - self.buffer_offset;
7708        let excerpt_offset = self.excerpt_offset + overshoot;
7709        let excerpt_seek_dim = excerpt_offset;
7710        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7711        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7712            log::warn!(
7713                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7714            );
7715            return self.offset..self.offset;
7716        }
7717        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7718        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7719
7720        let end = if buffer_range.start < buffer_range.end {
7721            let overshoot = buffer_range.end - self.buffer_offset;
7722            let excerpt_offset = self.excerpt_offset + overshoot;
7723            let excerpt_seek_dim = excerpt_offset;
7724            self.diff_transforms
7725                .seek_forward(&excerpt_seek_dim, Bias::Right);
7726            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7727            // todo(lw): Clamp end to the excerpt boundaries
7728            self.diff_transforms.start().output_dimension.0 + overshoot
7729        } else {
7730            start
7731        };
7732
7733        start..end
7734    }
7735
7736    /// Returns true if the entirety of the given range is in the buffer's excerpt
7737    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7738        range.start >= self.excerpt.buffer_start_offset()
7739            && range.end <= self.excerpt.buffer_end_offset()
7740    }
7741
7742    /// Returns true if any part of the given range is in the buffer's excerpt
7743    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7744        range.start <= self.excerpt.buffer_end_offset()
7745            && range.end >= self.excerpt.buffer_start_offset()
7746    }
7747
7748    pub fn max_buffer_row(&self) -> u32 {
7749        self.excerpt.max_buffer_row
7750    }
7751}
7752
7753impl ExcerptId {
7754    pub fn min() -> Self {
7755        Self(0)
7756    }
7757
7758    pub fn max() -> Self {
7759        Self(u32::MAX)
7760    }
7761
7762    pub fn to_proto(self) -> u64 {
7763        self.0 as _
7764    }
7765
7766    pub fn from_proto(proto: u64) -> Self {
7767        Self(proto as _)
7768    }
7769
7770    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7771        let a = snapshot.excerpt_locator_for_id(*self);
7772        let b = snapshot.excerpt_locator_for_id(*other);
7773        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7774    }
7775}
7776
7777impl From<ExcerptId> for usize {
7778    fn from(val: ExcerptId) -> Self {
7779        val.0 as usize
7780    }
7781}
7782
7783impl fmt::Debug for Excerpt {
7784    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7785        f.debug_struct("Excerpt")
7786            .field("id", &self.id)
7787            .field("locator", &self.locator)
7788            .field("buffer_id", &self.buffer_id)
7789            .field("range", &self.range)
7790            .field("text_summary", &self.text_summary)
7791            .field("has_trailing_newline", &self.has_trailing_newline)
7792            .finish()
7793    }
7794}
7795
7796impl sum_tree::Item for Excerpt {
7797    type Summary = ExcerptSummary;
7798
7799    fn summary(&self, _cx: ()) -> Self::Summary {
7800        let mut text = self.text_summary;
7801        if self.has_trailing_newline {
7802            text += TextSummary::from("\n");
7803        }
7804        ExcerptSummary {
7805            excerpt_id: self.id,
7806            excerpt_locator: self.locator.clone(),
7807            widest_line_number: self.max_buffer_row,
7808            text: text.into(),
7809        }
7810    }
7811}
7812
7813impl sum_tree::Item for ExcerptIdMapping {
7814    type Summary = ExcerptId;
7815
7816    fn summary(&self, _cx: ()) -> Self::Summary {
7817        self.id
7818    }
7819}
7820
7821impl sum_tree::KeyedItem for ExcerptIdMapping {
7822    type Key = ExcerptId;
7823
7824    fn key(&self) -> Self::Key {
7825        self.id
7826    }
7827}
7828
7829impl DiffTransform {
7830    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7831        match self {
7832            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7833            DiffTransform::BufferContent {
7834                inserted_hunk_info, ..
7835            } => *inserted_hunk_info,
7836        }
7837    }
7838}
7839
7840impl sum_tree::Item for DiffTransform {
7841    type Summary = DiffTransformSummary;
7842
7843    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7844        match self {
7845            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7846                input: *summary,
7847                output: *summary,
7848            },
7849            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7850                input: MBTextSummary::default(),
7851                output: summary.into(),
7852            },
7853        }
7854    }
7855}
7856
7857impl DiffTransformSummary {
7858    fn excerpt_len(&self) -> ExcerptOffset {
7859        ExcerptDimension(self.input.len)
7860    }
7861}
7862
7863impl sum_tree::ContextLessSummary for DiffTransformSummary {
7864    fn zero() -> Self {
7865        DiffTransformSummary {
7866            input: MBTextSummary::default(),
7867            output: MBTextSummary::default(),
7868        }
7869    }
7870
7871    fn add_summary(&mut self, other: &Self) {
7872        self.input += other.input;
7873        self.output += other.output;
7874    }
7875}
7876
7877impl sum_tree::ContextLessSummary for ExcerptId {
7878    fn zero() -> Self {
7879        Self(0)
7880    }
7881
7882    fn add_summary(&mut self, summary: &Self) {
7883        *self = cmp::max(*self, *summary);
7884    }
7885}
7886
7887impl sum_tree::ContextLessSummary for ExcerptSummary {
7888    fn zero() -> Self {
7889        Self::default()
7890    }
7891
7892    fn add_summary(&mut self, summary: &Self) {
7893        debug_assert!(
7894            summary.excerpt_locator > self.excerpt_locator
7895                || self.excerpt_locator == Locator::min(),
7896            "Excerpt locators must be in ascending order: {:?} > {:?}",
7897            summary.excerpt_locator,
7898            self.excerpt_locator
7899        );
7900        self.excerpt_locator = summary.excerpt_locator.clone();
7901        self.text += summary.text;
7902        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7903    }
7904}
7905
7906impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7907    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7908        Ord::cmp(&Some(self), cursor_location)
7909    }
7910}
7911
7912impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7913    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7914        Ord::cmp(self, &cursor_location.excerpt_locator)
7915    }
7916}
7917
7918impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7919where
7920    MBD: MultiBufferDimension + Default,
7921{
7922    fn zero(_: ()) -> Self {
7923        ExcerptDimension(MBD::default())
7924    }
7925
7926    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7927        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7928    }
7929}
7930
7931impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7932    fn zero(_cx: ()) -> Self {
7933        Default::default()
7934    }
7935
7936    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7937        *self = Some(&summary.excerpt_locator);
7938    }
7939}
7940
7941impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7942    fn zero(_cx: ()) -> Self {
7943        Default::default()
7944    }
7945
7946    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7947        *self = Some(summary.excerpt_id);
7948    }
7949}
7950
7951#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7952struct OutputDimension<T>(T);
7953
7954impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7955    fn eq(&self, other: &T) -> bool {
7956        self.0 == *other
7957    }
7958}
7959
7960impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7961    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7962        self.0.partial_cmp(other)
7963    }
7964}
7965
7966impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7967where
7968    T: ops::Sub<U, Output = R>,
7969{
7970    type Output = R;
7971
7972    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7973        self.0 - other.0
7974    }
7975}
7976
7977impl<R, T, U> ops::Add<U> for OutputDimension<T>
7978where
7979    T: ops::Add<U, Output = R>,
7980{
7981    type Output = OutputDimension<R>;
7982
7983    fn add(self, other: U) -> Self::Output {
7984        OutputDimension(self.0 + other)
7985    }
7986}
7987
7988impl<T, U> AddAssign<U> for OutputDimension<T>
7989where
7990    T: AddAssign<U>,
7991{
7992    fn add_assign(&mut self, other: U) {
7993        self.0 += other;
7994    }
7995}
7996
7997impl<T, U> SubAssign<U> for OutputDimension<T>
7998where
7999    T: SubAssign<U>,
8000{
8001    fn sub_assign(&mut self, other: U) {
8002        self.0 -= other;
8003    }
8004}
8005
8006#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8007struct ExcerptDimension<T>(T);
8008
8009impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8010    fn eq(&self, other: &T) -> bool {
8011        self.0 == *other
8012    }
8013}
8014
8015impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8016    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8017        self.0.partial_cmp(other)
8018    }
8019}
8020
8021impl ExcerptOffset {
8022    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8023        self.0.saturating_sub(other.0)
8024    }
8025}
8026
8027impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8028where
8029    T: ops::Sub<U, Output = R>,
8030{
8031    type Output = R;
8032
8033    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8034        self.0 - other.0
8035    }
8036}
8037
8038impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8039where
8040    T: ops::Add<U, Output = R>,
8041{
8042    type Output = ExcerptDimension<R>;
8043
8044    fn add(self, other: U) -> Self::Output {
8045        ExcerptDimension(self.0 + other)
8046    }
8047}
8048
8049impl<T, U> AddAssign<U> for ExcerptDimension<T>
8050where
8051    T: AddAssign<U>,
8052{
8053    fn add_assign(&mut self, other: U) {
8054        self.0 += other;
8055    }
8056}
8057
8058impl<T, U> SubAssign<U> for ExcerptDimension<T>
8059where
8060    T: SubAssign<U>,
8061{
8062    fn sub_assign(&mut self, other: U) {
8063        self.0 -= other;
8064    }
8065}
8066
8067impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8068    fn zero(_: ()) -> Self {
8069        MultiBufferOffset::ZERO
8070    }
8071
8072    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8073        *self += summary.output.len;
8074    }
8075}
8076
8077impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8078    for ExcerptDimension<MBD>
8079where
8080    MBD: MultiBufferDimension + Ord,
8081{
8082    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8083        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8084    }
8085}
8086
8087impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8088    for ExcerptDimension<MBD>
8089where
8090    MBD: MultiBufferDimension + Ord,
8091{
8092    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8093        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8094    }
8095}
8096
8097impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8098    for ExcerptDimension<MBD>
8099{
8100    fn zero(_: ()) -> Self {
8101        ExcerptDimension(MBD::default())
8102    }
8103
8104    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8105        self.0.add_mb_text_summary(&summary.input)
8106    }
8107}
8108
8109impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8110    for OutputDimension<MBD>
8111where
8112    MBD: MultiBufferDimension + Ord,
8113{
8114    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8115        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8116    }
8117}
8118
8119impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8120    for OutputDimension<MBD>
8121{
8122    fn zero(_: ()) -> Self {
8123        OutputDimension(MBD::default())
8124    }
8125
8126    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8127        self.0.add_mb_text_summary(&summary.output)
8128    }
8129}
8130
8131impl MultiBufferRows<'_> {
8132    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8133        self.point = Point::new(row, 0);
8134        self.cursor.seek(&self.point);
8135    }
8136}
8137
8138impl Iterator for MultiBufferRows<'_> {
8139    type Item = RowInfo;
8140
8141    fn next(&mut self) -> Option<Self::Item> {
8142        if self.is_empty && self.point.row == 0 {
8143            self.point += Point::new(1, 0);
8144            return Some(RowInfo {
8145                buffer_id: None,
8146                buffer_row: Some(0),
8147                multibuffer_row: Some(MultiBufferRow(0)),
8148                diff_status: None,
8149                expand_info: None,
8150                wrapped_buffer_row: None,
8151            });
8152        }
8153
8154        let mut region = self.cursor.region()?.clone();
8155        while self.point >= region.range.end {
8156            self.cursor.next();
8157            if let Some(next_region) = self.cursor.region() {
8158                region = next_region.clone();
8159            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8160                let multibuffer_row = MultiBufferRow(self.point.row);
8161                let last_excerpt = self
8162                    .cursor
8163                    .excerpts
8164                    .item()
8165                    .or(self.cursor.excerpts.prev_item())?;
8166                let last_row = last_excerpt
8167                    .range
8168                    .context
8169                    .end
8170                    .to_point(&last_excerpt.buffer)
8171                    .row;
8172
8173                let first_row = last_excerpt
8174                    .range
8175                    .context
8176                    .start
8177                    .to_point(&last_excerpt.buffer)
8178                    .row;
8179
8180                let expand_info = if self.is_singleton {
8181                    None
8182                } else {
8183                    let needs_expand_up = first_row == last_row
8184                        && last_row > 0
8185                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8186                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8187
8188                    if needs_expand_up && needs_expand_down {
8189                        Some(ExpandExcerptDirection::UpAndDown)
8190                    } else if needs_expand_up {
8191                        Some(ExpandExcerptDirection::Up)
8192                    } else if needs_expand_down {
8193                        Some(ExpandExcerptDirection::Down)
8194                    } else {
8195                        None
8196                    }
8197                    .map(|direction| ExpandInfo {
8198                        direction,
8199                        excerpt_id: last_excerpt.id,
8200                    })
8201                };
8202                self.point += Point::new(1, 0);
8203                return Some(RowInfo {
8204                    buffer_id: Some(last_excerpt.buffer_id),
8205                    buffer_row: Some(last_row),
8206                    multibuffer_row: Some(multibuffer_row),
8207                    diff_status: None,
8208                    wrapped_buffer_row: None,
8209                    expand_info,
8210                });
8211            } else {
8212                return None;
8213            };
8214        }
8215
8216        let overshoot = self.point - region.range.start;
8217        let buffer_point = region.buffer_range.start + overshoot;
8218        let expand_info = if self.is_singleton {
8219            None
8220        } else {
8221            let needs_expand_up = self.point.row == region.range.start.row
8222                && self.cursor.is_at_start_of_excerpt()
8223                && buffer_point.row > 0;
8224            let needs_expand_down = (region.excerpt.has_trailing_newline
8225                && self.point.row + 1 == region.range.end.row
8226                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8227                && self.cursor.is_at_end_of_excerpt()
8228                && buffer_point.row < region.buffer.max_point().row;
8229
8230            if needs_expand_up && needs_expand_down {
8231                Some(ExpandExcerptDirection::UpAndDown)
8232            } else if needs_expand_up {
8233                Some(ExpandExcerptDirection::Up)
8234            } else if needs_expand_down {
8235                Some(ExpandExcerptDirection::Down)
8236            } else {
8237                None
8238            }
8239            .map(|direction| ExpandInfo {
8240                direction,
8241                excerpt_id: region.excerpt.id,
8242            })
8243        };
8244
8245        let result = Some(RowInfo {
8246            buffer_id: Some(region.buffer.remote_id()),
8247            buffer_row: Some(buffer_point.row),
8248            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8249            diff_status: region
8250                .diff_hunk_status
8251                .filter(|_| self.point < region.range.end),
8252            expand_info,
8253            wrapped_buffer_row: None,
8254        });
8255        self.point += Point::new(1, 0);
8256        result
8257    }
8258}
8259
8260impl<'a> MultiBufferChunks<'a> {
8261    pub fn offset(&self) -> MultiBufferOffset {
8262        self.range.start
8263    }
8264
8265    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8266        self.diff_transforms.seek(&range.end, Bias::Right);
8267        let mut excerpt_end = self.diff_transforms.start().1;
8268        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8269            let overshoot = range.end - self.diff_transforms.start().0;
8270            excerpt_end += overshoot;
8271        }
8272
8273        self.diff_transforms.seek(&range.start, Bias::Right);
8274        let mut excerpt_start = self.diff_transforms.start().1;
8275        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8276            let overshoot = range.start - self.diff_transforms.start().0;
8277            excerpt_start += overshoot;
8278        }
8279
8280        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8281        self.buffer_chunk.take();
8282        self.range = range;
8283    }
8284
8285    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8286        self.excerpt_offset_range = new_range.clone();
8287        self.excerpts.seek(&new_range.start, Bias::Right);
8288        if let Some(excerpt) = self.excerpts.item() {
8289            let excerpt_start = *self.excerpts.start();
8290            if let Some(excerpt_chunks) = self
8291                .excerpt_chunks
8292                .as_mut()
8293                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8294            {
8295                excerpt.seek_chunks(
8296                    excerpt_chunks,
8297                    (self.excerpt_offset_range.start - excerpt_start)
8298                        ..(self.excerpt_offset_range.end - excerpt_start),
8299                );
8300            } else {
8301                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8302                    (self.excerpt_offset_range.start - excerpt_start)
8303                        ..(self.excerpt_offset_range.end - excerpt_start),
8304                    self.language_aware,
8305                ));
8306            }
8307        } else {
8308            self.excerpt_chunks = None;
8309        }
8310    }
8311
8312    #[ztracing::instrument(skip_all)]
8313    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8314        loop {
8315            if self.excerpt_offset_range.is_empty() {
8316                return None;
8317            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8318                self.excerpt_offset_range.start += chunk.text.len();
8319                return Some(chunk);
8320            } else {
8321                self.excerpts.next();
8322                let excerpt = self.excerpts.item()?;
8323                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8324                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8325                    self.language_aware,
8326                ));
8327            }
8328        }
8329    }
8330}
8331
8332impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8333    type Item = &'a str;
8334
8335    fn next(&mut self) -> Option<Self::Item> {
8336        let mut region = self.cursor.region()?;
8337        if self.offset == region.range.start {
8338            self.cursor.prev();
8339            region = self.cursor.region()?;
8340            let start_overshoot = self.start.saturating_sub(region.range.start);
8341            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8342                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8343            ));
8344        }
8345
8346        if self.offset == region.range.end && region.has_trailing_newline {
8347            self.offset -= 1;
8348            Some("\n")
8349        } else {
8350            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8351            self.offset -= chunk.len();
8352            Some(chunk)
8353        }
8354    }
8355}
8356
8357impl<'a> Iterator for MultiBufferChunks<'a> {
8358    type Item = Chunk<'a>;
8359
8360    #[ztracing::instrument(skip_all)]
8361    fn next(&mut self) -> Option<Chunk<'a>> {
8362        if self.range.start >= self.range.end {
8363            return None;
8364        }
8365        if self.range.start == self.diff_transforms.end().0 {
8366            self.diff_transforms.next();
8367        }
8368
8369        let diff_transform_start = self.diff_transforms.start().0;
8370        let diff_transform_end = self.diff_transforms.end().0;
8371        debug_assert!(
8372            self.range.start < diff_transform_end,
8373            "{:?} < {:?} of ({1:?}..{2:?})",
8374            self.range.start,
8375            diff_transform_end,
8376            diff_transform_start
8377        );
8378
8379        let diff_transform = self.diff_transforms.item()?;
8380        match diff_transform {
8381            DiffTransform::BufferContent { .. } => {
8382                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8383                    chunk
8384                } else {
8385                    let chunk = self.next_excerpt_chunk().unwrap();
8386                    self.buffer_chunk.insert(chunk)
8387                };
8388
8389                let chunk_end = self.range.start + chunk.text.len();
8390                let diff_transform_end = diff_transform_end.min(self.range.end);
8391
8392                if diff_transform_end < chunk_end {
8393                    let split_idx = diff_transform_end - self.range.start;
8394                    let (before, after) = chunk.text.split_at(split_idx);
8395                    self.range.start = diff_transform_end;
8396                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8397                    let chars = chunk.chars & mask;
8398                    let tabs = chunk.tabs & mask;
8399
8400                    chunk.text = after;
8401                    chunk.chars = chunk.chars >> split_idx;
8402                    chunk.tabs = chunk.tabs >> split_idx;
8403
8404                    Some(Chunk {
8405                        text: before,
8406                        chars,
8407                        tabs,
8408                        ..chunk.clone()
8409                    })
8410                } else {
8411                    self.range.start = chunk_end;
8412                    self.buffer_chunk.take()
8413                }
8414            }
8415            DiffTransform::DeletedHunk {
8416                buffer_id,
8417                base_text_byte_range,
8418                has_trailing_newline,
8419                ..
8420            } => {
8421                let base_text_start =
8422                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8423                let base_text_end =
8424                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8425                let base_text_end = base_text_end.min(base_text_byte_range.end);
8426
8427                let mut chunks = if let Some((_, mut chunks)) = self
8428                    .diff_base_chunks
8429                    .take()
8430                    .filter(|(id, _)| id == buffer_id)
8431                {
8432                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8433                    {
8434                        chunks.seek(base_text_start..base_text_end);
8435                    }
8436                    chunks
8437                } else {
8438                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8439                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8440                };
8441
8442                let chunk = if let Some(chunk) = chunks.next() {
8443                    self.range.start += chunk.text.len();
8444                    self.diff_base_chunks = Some((*buffer_id, chunks));
8445                    chunk
8446                } else {
8447                    debug_assert!(has_trailing_newline);
8448                    self.range.start += "\n".len();
8449                    Chunk {
8450                        text: "\n",
8451                        chars: 1u128,
8452                        ..Default::default()
8453                    }
8454                };
8455                Some(chunk)
8456            }
8457        }
8458    }
8459}
8460
8461impl MultiBufferBytes<'_> {
8462    fn consume(&mut self, len: usize) {
8463        self.range.start += len;
8464        self.chunk = &self.chunk[len..];
8465
8466        if !self.range.is_empty() && self.chunk.is_empty() {
8467            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8468                self.chunk = chunk;
8469            } else if self.has_trailing_newline {
8470                self.has_trailing_newline = false;
8471                self.chunk = b"\n";
8472            } else {
8473                self.cursor.next();
8474                if let Some(region) = self.cursor.region() {
8475                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8476                        region.buffer_range.start
8477                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8478                                .min(region.buffer_range.end),
8479                    );
8480                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8481                    self.excerpt_bytes = Some(excerpt_bytes);
8482                    self.has_trailing_newline =
8483                        region.has_trailing_newline && self.range.end >= region.range.end;
8484                    if self.chunk.is_empty() && self.has_trailing_newline {
8485                        self.has_trailing_newline = false;
8486                        self.chunk = b"\n";
8487                    }
8488                }
8489            }
8490        }
8491    }
8492}
8493
8494impl<'a> Iterator for MultiBufferBytes<'a> {
8495    type Item = &'a [u8];
8496
8497    fn next(&mut self) -> Option<Self::Item> {
8498        let chunk = self.chunk;
8499        if chunk.is_empty() {
8500            None
8501        } else {
8502            self.consume(chunk.len());
8503            Some(chunk)
8504        }
8505    }
8506}
8507
8508impl io::Read for MultiBufferBytes<'_> {
8509    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8510        let len = cmp::min(buf.len(), self.chunk.len());
8511        buf[..len].copy_from_slice(&self.chunk[..len]);
8512        if len > 0 {
8513            self.consume(len);
8514        }
8515        Ok(len)
8516    }
8517}
8518
8519impl io::Read for ReversedMultiBufferBytes<'_> {
8520    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8521        let len = cmp::min(buf.len(), self.chunk.len());
8522        buf[..len].copy_from_slice(&self.chunk[..len]);
8523        buf[..len].reverse();
8524        if len > 0 {
8525            self.range.end -= len;
8526            self.chunk = &self.chunk[..self.chunk.len() - len];
8527            if !self.range.is_empty()
8528                && self.chunk.is_empty()
8529                && let Some(chunk) = self.chunks.next()
8530            {
8531                self.chunk = chunk.as_bytes();
8532            }
8533        }
8534        Ok(len)
8535    }
8536}
8537
8538impl<'a> Iterator for ExcerptChunks<'a> {
8539    type Item = Chunk<'a>;
8540
8541    fn next(&mut self) -> Option<Self::Item> {
8542        if let Some(chunk) = self.content_chunks.next() {
8543            return Some(chunk);
8544        }
8545
8546        if self.has_footer {
8547            let text = "\n";
8548            let chars = 0b1;
8549            self.has_footer = false;
8550            return Some(Chunk {
8551                text,
8552                chars,
8553                ..Default::default()
8554            });
8555        }
8556
8557        None
8558    }
8559}
8560
8561impl ToOffset for Point {
8562    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8563        snapshot.point_to_offset(*self)
8564    }
8565    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8566        snapshot.point_to_offset_utf16(*self)
8567    }
8568}
8569
8570impl ToOffset for MultiBufferOffset {
8571    #[track_caller]
8572    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8573        assert!(
8574            *self <= snapshot.len(),
8575            "offset {} is greater than the snapshot.len() {}",
8576            self.0,
8577            snapshot.len().0,
8578        );
8579        *self
8580    }
8581    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8582        snapshot.offset_to_offset_utf16(*self)
8583    }
8584}
8585
8586impl ToOffset for MultiBufferOffsetUtf16 {
8587    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8588        snapshot.offset_utf16_to_offset(*self)
8589    }
8590
8591    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8592        *self
8593    }
8594}
8595
8596impl ToOffset for PointUtf16 {
8597    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8598        snapshot.point_utf16_to_offset(*self)
8599    }
8600    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8601        snapshot.point_utf16_to_offset_utf16(*self)
8602    }
8603}
8604
8605impl ToPoint for MultiBufferOffset {
8606    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8607        snapshot.offset_to_point(*self)
8608    }
8609    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8610        snapshot.offset_to_point_utf16(*self)
8611    }
8612}
8613
8614impl ToPoint for Point {
8615    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8616        *self
8617    }
8618    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8619        snapshot.point_to_point_utf16(*self)
8620    }
8621}
8622
8623impl ToPoint for PointUtf16 {
8624    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8625        snapshot.point_utf16_to_point(*self)
8626    }
8627    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8628        *self
8629    }
8630}
8631
8632impl From<ExcerptId> for EntityId {
8633    fn from(id: ExcerptId) -> Self {
8634        EntityId::from(id.0 as u64)
8635    }
8636}
8637
8638#[cfg(debug_assertions)]
8639pub mod debug {
8640    use super::*;
8641
8642    pub trait ToMultiBufferDebugRanges {
8643        fn to_multi_buffer_debug_ranges(
8644            &self,
8645            snapshot: &MultiBufferSnapshot,
8646        ) -> Vec<Range<MultiBufferOffset>>;
8647    }
8648
8649    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8650        fn to_multi_buffer_debug_ranges(
8651            &self,
8652            snapshot: &MultiBufferSnapshot,
8653        ) -> Vec<Range<MultiBufferOffset>> {
8654            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8655        }
8656    }
8657
8658    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8659        fn to_multi_buffer_debug_ranges(
8660            &self,
8661            snapshot: &MultiBufferSnapshot,
8662        ) -> Vec<Range<MultiBufferOffset>> {
8663            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8664                .to_multi_buffer_debug_ranges(snapshot)
8665        }
8666    }
8667
8668    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8669        fn to_multi_buffer_debug_ranges(
8670            &self,
8671            snapshot: &MultiBufferSnapshot,
8672        ) -> Vec<Range<MultiBufferOffset>> {
8673            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8674        }
8675    }
8676
8677    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8678        fn to_multi_buffer_debug_ranges(
8679            &self,
8680            snapshot: &MultiBufferSnapshot,
8681        ) -> Vec<Range<MultiBufferOffset>> {
8682            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8683        }
8684    }
8685
8686    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8687        fn to_multi_buffer_debug_ranges(
8688            &self,
8689            snapshot: &MultiBufferSnapshot,
8690        ) -> Vec<Range<MultiBufferOffset>> {
8691            self.iter()
8692                .map(|item| {
8693                    let offset = item.to_offset(snapshot);
8694                    offset..offset
8695                })
8696                .collect()
8697        }
8698    }
8699
8700    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8701        fn to_multi_buffer_debug_ranges(
8702            &self,
8703            snapshot: &MultiBufferSnapshot,
8704        ) -> Vec<Range<MultiBufferOffset>> {
8705            self.iter()
8706                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8707                .collect()
8708        }
8709    }
8710}