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        /// Contains only buffer IDs for which all excerpts have been removed.
 109        /// Buffers that still have remaining excerpts are never included.
 110        removed_buffer_ids: Vec<BufferId>,
 111    },
 112    ExcerptsExpanded {
 113        ids: Vec<ExcerptId>,
 114    },
 115    ExcerptsEdited {
 116        excerpt_ids: Vec<ExcerptId>,
 117        buffer_ids: Vec<BufferId>,
 118    },
 119    DiffHunksToggled,
 120    Edited {
 121        edited_buffer: Option<Entity<Buffer>>,
 122    },
 123    TransactionUndone {
 124        transaction_id: TransactionId,
 125    },
 126    Reloaded,
 127    LanguageChanged(BufferId, bool),
 128    Reparsed(BufferId),
 129    Saved,
 130    FileHandleChanged,
 131    DirtyChanged,
 132    DiagnosticsUpdated,
 133    BufferDiffChanged,
 134}
 135
 136/// A diff hunk, representing a range of consequent lines in a multibuffer.
 137#[derive(Debug, Clone, PartialEq, Eq)]
 138pub struct MultiBufferDiffHunk {
 139    /// The row range in the multibuffer where this diff hunk appears.
 140    pub row_range: Range<MultiBufferRow>,
 141    /// The buffer ID that this hunk belongs to.
 142    pub buffer_id: BufferId,
 143    /// The range of the underlying buffer that this hunk corresponds to.
 144    pub buffer_range: Range<text::Anchor>,
 145    /// The excerpt that contains the diff hunk.
 146    pub excerpt_id: ExcerptId,
 147    /// The range within the buffer's diff base that this hunk corresponds to.
 148    pub diff_base_byte_range: Range<BufferOffset>,
 149    /// The status of this hunk (added/modified/deleted and secondary status).
 150    pub status: DiffHunkStatus,
 151    /// The word diffs for this hunk.
 152    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 153}
 154
 155impl MultiBufferDiffHunk {
 156    pub fn status(&self) -> DiffHunkStatus {
 157        self.status
 158    }
 159
 160    pub fn is_created_file(&self) -> bool {
 161        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 162            && self.buffer_range.start.is_min()
 163            && self.buffer_range.end.is_max()
 164    }
 165
 166    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 167        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 168        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 169        start..end
 170    }
 171}
 172
 173pub type MultiBufferPoint = Point;
 174type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 175type ExcerptPoint = ExcerptDimension<Point>;
 176
 177#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 178#[serde(transparent)]
 179pub struct MultiBufferRow(pub u32);
 180
 181impl MultiBufferRow {
 182    pub const MIN: Self = Self(0);
 183    pub const MAX: Self = Self(u32::MAX);
 184}
 185
 186impl ops::Add<usize> for MultiBufferRow {
 187    type Output = Self;
 188
 189    fn add(self, rhs: usize) -> Self::Output {
 190        MultiBufferRow(self.0 + rhs as u32)
 191    }
 192}
 193
 194pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 195    type TextDimension: TextDimension;
 196    fn from_summary(summary: &MBTextSummary) -> Self;
 197
 198    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 199
 200    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 201}
 202
 203// todo(lw): MultiBufferPoint
 204impl MultiBufferDimension for Point {
 205    type TextDimension = Point;
 206    fn from_summary(summary: &MBTextSummary) -> Self {
 207        summary.lines
 208    }
 209
 210    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 211        *self += *other;
 212    }
 213
 214    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 215        *self += summary.lines;
 216    }
 217}
 218
 219// todo(lw): MultiBufferPointUtf16
 220impl MultiBufferDimension for PointUtf16 {
 221    type TextDimension = PointUtf16;
 222    fn from_summary(summary: &MBTextSummary) -> Self {
 223        summary.lines_utf16()
 224    }
 225
 226    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 227        *self += *other;
 228    }
 229
 230    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 231        *self += summary.lines_utf16();
 232    }
 233}
 234
 235#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 236pub struct MultiBufferOffset(pub usize);
 237
 238impl fmt::Display for MultiBufferOffset {
 239    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 240        write!(f, "{}", self.0)
 241    }
 242}
 243
 244impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 245    type Sampler = MultiBufferOffsetUniformSampler;
 246}
 247
 248pub struct MultiBufferOffsetUniformSampler {
 249    sampler: rand::distr::uniform::UniformUsize,
 250}
 251
 252impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 253    type X = MultiBufferOffset;
 254
 255    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 256    where
 257        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 258        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259    {
 260        let low = *low_b.borrow();
 261        let high = *high_b.borrow();
 262        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 263        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 264    }
 265
 266    #[inline] // if the range is constant, this helps LLVM to do the
 267    // calculations at compile-time.
 268    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 269    where
 270        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 271        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272    {
 273        let low = *low_b.borrow();
 274        let high = *high_b.borrow();
 275        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 276        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 277    }
 278
 279    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 280        MultiBufferOffset(self.sampler.sample(rng))
 281    }
 282}
 283impl MultiBufferDimension for MultiBufferOffset {
 284    type TextDimension = usize;
 285    fn from_summary(summary: &MBTextSummary) -> Self {
 286        summary.len
 287    }
 288
 289    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 290        self.0 += *other;
 291    }
 292
 293    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 294        *self += summary.len;
 295    }
 296}
 297impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 298    type TextDimension = OffsetUtf16;
 299    fn from_summary(summary: &MBTextSummary) -> Self {
 300        MultiBufferOffsetUtf16(summary.len_utf16)
 301    }
 302
 303    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 304        self.0 += *other;
 305    }
 306
 307    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 308        self.0 += summary.len_utf16;
 309    }
 310}
 311
 312#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 313pub struct BufferOffset(pub usize);
 314
 315impl TextDimension for BufferOffset {
 316    fn from_text_summary(summary: &TextSummary) -> Self {
 317        BufferOffset(usize::from_text_summary(summary))
 318    }
 319    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 320        BufferOffset(usize::from_chunk(chunk))
 321    }
 322    fn add_assign(&mut self, other: &Self) {
 323        TextDimension::add_assign(&mut self.0, &other.0);
 324    }
 325}
 326impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 327    fn zero(cx: ()) -> Self {
 328        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 329    }
 330
 331    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 332        usize::add_summary(&mut self.0, summary, cx);
 333    }
 334}
 335
 336impl Sub for BufferOffset {
 337    type Output = usize;
 338
 339    fn sub(self, other: BufferOffset) -> Self::Output {
 340        self.0 - other.0
 341    }
 342}
 343
 344impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 345    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 346        self.0 += other.key;
 347    }
 348}
 349
 350impl language::ToPoint for BufferOffset {
 351    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 352        self.0.to_point(snapshot)
 353    }
 354}
 355
 356impl language::ToPointUtf16 for BufferOffset {
 357    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 358        self.0.to_point_utf16(snapshot)
 359    }
 360}
 361
 362impl language::ToOffset for BufferOffset {
 363    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 364        self.0.to_offset(snapshot)
 365    }
 366}
 367
 368impl language::ToOffsetUtf16 for BufferOffset {
 369    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 370        self.0.to_offset_utf16(snapshot)
 371    }
 372}
 373
 374#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 375pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 376
 377impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 378    type Output = MultiBufferOffsetUtf16;
 379
 380    fn add(self, rhs: usize) -> Self::Output {
 381        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 382    }
 383}
 384
 385impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 386    type Output = Self;
 387
 388    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 389        MultiBufferOffsetUtf16(self.0 + rhs)
 390    }
 391}
 392
 393impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 394    fn add_assign(&mut self, rhs: OffsetUtf16) {
 395        self.0 += rhs;
 396    }
 397}
 398
 399impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 400    fn add_assign(&mut self, rhs: usize) {
 401        self.0.0 += rhs;
 402    }
 403}
 404
 405impl Sub for MultiBufferOffsetUtf16 {
 406    type Output = OffsetUtf16;
 407
 408    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 409        self.0 - other.0
 410    }
 411}
 412
 413impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 414    type Output = MultiBufferOffsetUtf16;
 415
 416    fn sub(self, other: OffsetUtf16) -> Self::Output {
 417        MultiBufferOffsetUtf16(self.0 - other)
 418    }
 419}
 420
 421#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 422pub struct BufferOffsetUtf16(pub OffsetUtf16);
 423
 424impl MultiBufferOffset {
 425    const ZERO: Self = Self(0);
 426    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 427        self.0.saturating_sub(other.0)
 428    }
 429    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 430        MultiBufferOffset(self.0.saturating_sub(other))
 431    }
 432}
 433
 434impl ops::Sub for MultiBufferOffset {
 435    type Output = usize;
 436
 437    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 438        self.0 - other.0
 439    }
 440}
 441
 442impl ops::Sub<usize> for MultiBufferOffset {
 443    type Output = Self;
 444
 445    fn sub(self, other: usize) -> Self::Output {
 446        MultiBufferOffset(self.0 - other)
 447    }
 448}
 449
 450impl ops::SubAssign<usize> for MultiBufferOffset {
 451    fn sub_assign(&mut self, other: usize) {
 452        self.0 -= other;
 453    }
 454}
 455
 456impl ops::Add<usize> for BufferOffset {
 457    type Output = Self;
 458
 459    fn add(self, rhs: usize) -> Self::Output {
 460        BufferOffset(self.0 + rhs)
 461    }
 462}
 463
 464impl ops::AddAssign<usize> for BufferOffset {
 465    fn add_assign(&mut self, other: usize) {
 466        self.0 += other;
 467    }
 468}
 469
 470impl ops::Add<usize> for MultiBufferOffset {
 471    type Output = Self;
 472
 473    fn add(self, rhs: usize) -> Self::Output {
 474        MultiBufferOffset(self.0 + rhs)
 475    }
 476}
 477
 478impl ops::AddAssign<usize> for MultiBufferOffset {
 479    fn add_assign(&mut self, other: usize) {
 480        self.0 += other;
 481    }
 482}
 483
 484impl ops::Add<isize> for MultiBufferOffset {
 485    type Output = Self;
 486
 487    fn add(self, rhs: isize) -> Self::Output {
 488        MultiBufferOffset((self.0 as isize + rhs) as usize)
 489    }
 490}
 491
 492impl ops::Add for MultiBufferOffset {
 493    type Output = Self;
 494
 495    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 496        MultiBufferOffset(self.0 + rhs.0)
 497    }
 498}
 499
 500impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 501    fn add_assign(&mut self, other: MultiBufferOffset) {
 502        self.0 += other.0;
 503    }
 504}
 505
 506pub trait ToOffset: 'static + fmt::Debug {
 507    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 508    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 509}
 510
 511pub trait ToPoint: 'static + fmt::Debug {
 512    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 513    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 514}
 515
 516struct BufferState {
 517    buffer: Entity<Buffer>,
 518    last_version: RefCell<clock::Global>,
 519    last_non_text_state_update_count: Cell<usize>,
 520    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 521    excerpts: Vec<Locator>,
 522    _subscriptions: [gpui::Subscription; 2],
 523}
 524
 525struct DiffState {
 526    diff: Entity<BufferDiff>,
 527    main_buffer: Option<Entity<language::Buffer>>,
 528    _subscription: gpui::Subscription,
 529}
 530
 531impl DiffState {
 532    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 533        DiffStateSnapshot {
 534            diff: self.diff.read(cx).snapshot(cx),
 535            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 536        }
 537    }
 538}
 539
 540#[derive(Clone)]
 541struct DiffStateSnapshot {
 542    diff: BufferDiffSnapshot,
 543    main_buffer: Option<language::BufferSnapshot>,
 544}
 545
 546impl std::ops::Deref for DiffStateSnapshot {
 547    type Target = BufferDiffSnapshot;
 548
 549    fn deref(&self) -> &Self::Target {
 550        &self.diff
 551    }
 552}
 553
 554impl DiffState {
 555    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 556        DiffState {
 557            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 558                BufferDiffEvent::DiffChanged(DiffChanged {
 559                    changed_range,
 560                    base_text_changed_range: _,
 561                    extended_range,
 562                }) => {
 563                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 564                    let range = if use_extended {
 565                        extended_range.clone()
 566                    } else {
 567                        changed_range.clone()
 568                    };
 569                    if let Some(range) = range {
 570                        this.buffer_diff_changed(diff, range, cx)
 571                    }
 572                    cx.emit(Event::BufferDiffChanged);
 573                }
 574                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 575                _ => {}
 576            }),
 577            diff,
 578            main_buffer: None,
 579        }
 580    }
 581
 582    fn new_inverted(
 583        diff: Entity<BufferDiff>,
 584        main_buffer: Entity<language::Buffer>,
 585        cx: &mut Context<MultiBuffer>,
 586    ) -> Self {
 587        let weak_main_buffer = main_buffer.downgrade();
 588        DiffState {
 589            _subscription: cx.subscribe(&diff, {
 590                move |this, diff, event, cx| {
 591                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 592                        return;
 593                    };
 594                    match event {
 595                        BufferDiffEvent::DiffChanged(DiffChanged {
 596                            changed_range: _,
 597                            base_text_changed_range,
 598                            extended_range: _,
 599                        }) => {
 600                            this.inverted_buffer_diff_changed(
 601                                diff,
 602                                main_buffer,
 603                                base_text_changed_range.clone(),
 604                                cx,
 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: Arc<HashMap<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    count: usize,
 818}
 819
 820#[derive(Debug, Clone)]
 821pub struct DiffTransformSummary {
 822    input: MBTextSummary,
 823    output: MBTextSummary,
 824}
 825
 826/// Summary of a string of text.
 827#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 828pub struct MBTextSummary {
 829    /// Length in bytes.
 830    pub len: MultiBufferOffset,
 831    /// Length in UTF-8.
 832    pub chars: usize,
 833    /// Length in UTF-16 code units
 834    pub len_utf16: OffsetUtf16,
 835    /// A point representing the number of lines and the length of the last line.
 836    ///
 837    /// In other words, it marks the point after the last byte in the text, (if
 838    /// EOF was a character, this would be its position).
 839    pub lines: Point,
 840    /// How many `char`s are in the first line
 841    pub first_line_chars: u32,
 842    /// How many `char`s are in the last line
 843    pub last_line_chars: u32,
 844    /// How many UTF-16 code units are in the last line
 845    pub last_line_len_utf16: u32,
 846    /// The row idx of the longest row
 847    pub longest_row: u32,
 848    /// How many `char`s are in the longest row
 849    pub longest_row_chars: u32,
 850}
 851
 852impl From<TextSummary> for MBTextSummary {
 853    fn from(summary: TextSummary) -> Self {
 854        MBTextSummary {
 855            len: MultiBufferOffset(summary.len),
 856            chars: summary.chars,
 857            len_utf16: summary.len_utf16,
 858            lines: summary.lines,
 859            first_line_chars: summary.first_line_chars,
 860            last_line_chars: summary.last_line_chars,
 861            last_line_len_utf16: summary.last_line_len_utf16,
 862            longest_row: summary.longest_row,
 863            longest_row_chars: summary.longest_row_chars,
 864        }
 865    }
 866}
 867
 868impl From<MBTextSummary> for TextSummary {
 869    fn from(summary: MBTextSummary) -> Self {
 870        TextSummary {
 871            len: summary.len.0,
 872            chars: summary.chars,
 873            len_utf16: summary.len_utf16,
 874            lines: summary.lines,
 875            first_line_chars: summary.first_line_chars,
 876            last_line_chars: summary.last_line_chars,
 877            last_line_len_utf16: summary.last_line_len_utf16,
 878            longest_row: summary.longest_row,
 879            longest_row_chars: summary.longest_row_chars,
 880        }
 881    }
 882}
 883
 884impl From<&str> for MBTextSummary {
 885    fn from(text: &str) -> Self {
 886        MBTextSummary::from(TextSummary::from(text))
 887    }
 888}
 889
 890impl MultiBufferDimension for MBTextSummary {
 891    type TextDimension = TextSummary;
 892
 893    fn from_summary(summary: &MBTextSummary) -> Self {
 894        *summary
 895    }
 896
 897    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 898        *self += *summary;
 899    }
 900
 901    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 902        *self += *summary;
 903    }
 904}
 905
 906impl AddAssign for MBTextSummary {
 907    fn add_assign(&mut self, other: MBTextSummary) {
 908        let joined_chars = self.last_line_chars + other.first_line_chars;
 909        if joined_chars > self.longest_row_chars {
 910            self.longest_row = self.lines.row;
 911            self.longest_row_chars = joined_chars;
 912        }
 913        if other.longest_row_chars > self.longest_row_chars {
 914            self.longest_row = self.lines.row + other.longest_row;
 915            self.longest_row_chars = other.longest_row_chars;
 916        }
 917
 918        if self.lines.row == 0 {
 919            self.first_line_chars += other.first_line_chars;
 920        }
 921
 922        if other.lines.row == 0 {
 923            self.last_line_chars += other.first_line_chars;
 924            self.last_line_len_utf16 += other.last_line_len_utf16;
 925        } else {
 926            self.last_line_chars = other.last_line_chars;
 927            self.last_line_len_utf16 = other.last_line_len_utf16;
 928        }
 929
 930        self.chars += other.chars;
 931        self.len += other.len;
 932        self.len_utf16 += other.len_utf16;
 933        self.lines += other.lines;
 934    }
 935}
 936
 937impl AddAssign<TextSummary> for MBTextSummary {
 938    fn add_assign(&mut self, other: TextSummary) {
 939        *self += MBTextSummary::from(other);
 940    }
 941}
 942
 943impl MBTextSummary {
 944    pub fn lines_utf16(&self) -> PointUtf16 {
 945        PointUtf16 {
 946            row: self.lines.row,
 947            column: self.last_line_len_utf16,
 948        }
 949    }
 950}
 951
 952impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 953where
 954    K: MultiBufferDimension,
 955    V: MultiBufferDimension,
 956{
 957    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 958
 959    fn from_summary(summary: &MBTextSummary) -> Self {
 960        Self {
 961            key: K::from_summary(summary),
 962            value: Some(V::from_summary(summary)),
 963        }
 964    }
 965
 966    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 967        self.key.add_text_dim(&summary.key);
 968        if let Some(value) = &mut self.value {
 969            if let Some(other_value) = summary.value.as_ref() {
 970                value.add_text_dim(other_value);
 971            }
 972        }
 973    }
 974
 975    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 976        self.key.add_mb_text_summary(summary);
 977        if let Some(value) = &mut self.value {
 978            value.add_mb_text_summary(summary);
 979        }
 980    }
 981}
 982
 983#[derive(Clone)]
 984pub struct MultiBufferRows<'a> {
 985    point: Point,
 986    is_empty: bool,
 987    is_singleton: bool,
 988    cursor: MultiBufferCursor<'a, Point, Point>,
 989}
 990
 991pub struct MultiBufferChunks<'a> {
 992    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 993    diff_transforms:
 994        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 995    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 996    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 997    buffer_chunk: Option<Chunk<'a>>,
 998    range: Range<MultiBufferOffset>,
 999    excerpt_offset_range: Range<ExcerptOffset>,
1000    excerpt_chunks: Option<ExcerptChunks<'a>>,
1001    language_aware: bool,
1002}
1003
1004pub struct ReversedMultiBufferChunks<'a> {
1005    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1006    current_chunks: Option<rope::Chunks<'a>>,
1007    start: MultiBufferOffset,
1008    offset: MultiBufferOffset,
1009}
1010
1011pub struct MultiBufferBytes<'a> {
1012    range: Range<MultiBufferOffset>,
1013    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1014    excerpt_bytes: Option<text::Bytes<'a>>,
1015    has_trailing_newline: bool,
1016    chunk: &'a [u8],
1017}
1018
1019pub struct ReversedMultiBufferBytes<'a> {
1020    range: Range<MultiBufferOffset>,
1021    chunks: ReversedMultiBufferChunks<'a>,
1022    chunk: &'a [u8],
1023}
1024
1025#[derive(Clone)]
1026struct DiffTransforms<MBD> {
1027    output_dimension: OutputDimension<MBD>,
1028    excerpt_dimension: ExcerptDimension<MBD>,
1029}
1030
1031impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1032    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1033        Self {
1034            output_dimension: OutputDimension::zero(cx),
1035            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1036                cx,
1037            ),
1038        }
1039    }
1040
1041    fn add_summary(
1042        &mut self,
1043        summary: &'a DiffTransformSummary,
1044        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1045    ) {
1046        self.output_dimension.add_summary(summary, cx);
1047        self.excerpt_dimension.add_summary(summary, cx);
1048    }
1049}
1050
1051#[derive(Clone)]
1052struct MultiBufferCursor<'a, MBD, BD> {
1053    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1054    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1055    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1056    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1057}
1058
1059#[derive(Clone)]
1060struct MultiBufferRegion<'a, MBD, BD> {
1061    buffer: &'a BufferSnapshot,
1062    is_main_buffer: bool,
1063    diff_hunk_status: Option<DiffHunkStatus>,
1064    excerpt: &'a Excerpt,
1065    buffer_range: Range<BD>,
1066    range: Range<MBD>,
1067    has_trailing_newline: bool,
1068}
1069
1070struct ExcerptChunks<'a> {
1071    excerpt_id: ExcerptId,
1072    content_chunks: BufferChunks<'a>,
1073    has_footer: bool,
1074}
1075
1076#[derive(Debug)]
1077struct BufferEdit {
1078    range: Range<BufferOffset>,
1079    new_text: Arc<str>,
1080    is_insertion: bool,
1081    original_indent_column: Option<u32>,
1082    excerpt_id: ExcerptId,
1083}
1084
1085#[derive(Clone, Copy, Debug, PartialEq)]
1086enum DiffChangeKind {
1087    BufferEdited,
1088    DiffUpdated { base_changed: bool },
1089    ExpandOrCollapseHunks { expand: bool },
1090}
1091
1092#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1093pub enum ExpandExcerptDirection {
1094    Up,
1095    Down,
1096    UpAndDown,
1097}
1098
1099impl ExpandExcerptDirection {
1100    pub fn should_expand_up(&self) -> bool {
1101        match self {
1102            ExpandExcerptDirection::Up => true,
1103            ExpandExcerptDirection::Down => false,
1104            ExpandExcerptDirection::UpAndDown => true,
1105        }
1106    }
1107
1108    pub fn should_expand_down(&self) -> bool {
1109        match self {
1110            ExpandExcerptDirection::Up => false,
1111            ExpandExcerptDirection::Down => true,
1112            ExpandExcerptDirection::UpAndDown => true,
1113        }
1114    }
1115}
1116
1117#[derive(Clone, Debug, PartialEq)]
1118pub struct IndentGuide {
1119    pub buffer_id: BufferId,
1120    pub start_row: MultiBufferRow,
1121    pub end_row: MultiBufferRow,
1122    pub depth: u32,
1123    pub tab_size: u32,
1124    pub settings: IndentGuideSettings,
1125}
1126
1127impl IndentGuide {
1128    pub fn indent_level(&self) -> u32 {
1129        self.depth * self.tab_size
1130    }
1131}
1132
1133impl MultiBuffer {
1134    pub fn new(capability: Capability) -> Self {
1135        Self::new_(
1136            capability,
1137            MultiBufferSnapshot {
1138                show_headers: true,
1139                show_deleted_hunks: true,
1140                ..MultiBufferSnapshot::default()
1141            },
1142        )
1143    }
1144
1145    pub fn without_headers(capability: Capability) -> Self {
1146        Self::new_(
1147            capability,
1148            MultiBufferSnapshot {
1149                show_deleted_hunks: true,
1150                ..MultiBufferSnapshot::default()
1151            },
1152        )
1153    }
1154
1155    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1156        let mut this = Self::new_(
1157            buffer.read(cx).capability(),
1158            MultiBufferSnapshot {
1159                singleton: true,
1160                show_deleted_hunks: true,
1161                ..MultiBufferSnapshot::default()
1162            },
1163        );
1164        this.singleton = true;
1165        this.set_excerpts_for_path(
1166            PathKey::sorted(0),
1167            buffer.clone(),
1168            [Point::zero()..buffer.read(cx).max_point()],
1169            0,
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    #[instrument(skip_all)]
1739    fn merge_excerpt_ranges<'a>(
1740        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1741    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1742        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1743        let mut counts: Vec<usize> = Vec::new();
1744        for range in expanded_ranges {
1745            if let Some(last_range) = merged_ranges.last_mut() {
1746                assert!(
1747                    last_range.context.start <= range.context.start,
1748                    "ranges must be sorted: {last_range:?} <= {range:?}"
1749                );
1750                if last_range.context.end >= range.context.start
1751                    || last_range.context.end.row + 1 == range.context.start.row
1752                {
1753                    last_range.context.end = range.context.end.max(last_range.context.end);
1754                    *counts.last_mut().unwrap() += 1;
1755                    continue;
1756                }
1757            }
1758            merged_ranges.push(range.clone());
1759            counts.push(1);
1760        }
1761        (merged_ranges, counts)
1762    }
1763
1764    pub fn insert_excerpts_after<O>(
1765        &mut self,
1766        prev_excerpt_id: ExcerptId,
1767        buffer: Entity<Buffer>,
1768        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1769        cx: &mut Context<Self>,
1770    ) -> Vec<ExcerptId>
1771    where
1772        O: text::ToOffset,
1773    {
1774        let mut ids = Vec::new();
1775        let mut next_excerpt_id =
1776            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1777                last_entry.id.0 + 1
1778            } else {
1779                1
1780            };
1781        self.insert_excerpts_with_ids_after(
1782            prev_excerpt_id,
1783            buffer,
1784            ranges.into_iter().map(|range| {
1785                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1786                ids.push(id);
1787                (id, range)
1788            }),
1789            cx,
1790        );
1791        ids
1792    }
1793
1794    pub fn insert_excerpts_with_ids_after<O>(
1795        &mut self,
1796        prev_excerpt_id: ExcerptId,
1797        buffer: Entity<Buffer>,
1798        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1799        cx: &mut Context<Self>,
1800    ) where
1801        O: text::ToOffset,
1802    {
1803        assert_eq!(self.history.transaction_depth(), 0);
1804        let mut ranges = ranges.into_iter().peekable();
1805        if ranges.peek().is_none() {
1806            return Default::default();
1807        }
1808
1809        self.sync_mut(cx);
1810
1811        let buffer_snapshot = buffer.read(cx).snapshot();
1812        let buffer_id = buffer_snapshot.remote_id();
1813
1814        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1815            self.buffer_changed_since_sync.replace(true);
1816            buffer.update(cx, |buffer, _| {
1817                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1818            });
1819            BufferState {
1820                last_version: RefCell::new(buffer_snapshot.version().clone()),
1821                last_non_text_state_update_count: Cell::new(
1822                    buffer_snapshot.non_text_state_update_count(),
1823                ),
1824                excerpts: Default::default(),
1825                _subscriptions: [
1826                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1827                    cx.subscribe(&buffer, Self::on_buffer_event),
1828                ],
1829                buffer: buffer.clone(),
1830            }
1831        });
1832
1833        let mut snapshot = self.snapshot.get_mut();
1834
1835        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1836        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1837        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1838        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1839        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1840
1841        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1842        new_excerpts.update_last(
1843            |excerpt| {
1844                excerpt.has_trailing_newline = true;
1845            },
1846            (),
1847        );
1848
1849        let next_locator = if let Some(excerpt) = cursor.item() {
1850            excerpt.locator.clone()
1851        } else {
1852            Locator::max()
1853        };
1854
1855        let mut excerpts = Vec::new();
1856        let buffer_snapshot = Arc::new(buffer_snapshot);
1857        while let Some((id, range)) = ranges.next() {
1858            let locator = Locator::between(&prev_locator, &next_locator);
1859            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1860                buffer_state.excerpts.insert(ix, locator.clone());
1861            }
1862            let range = ExcerptRange {
1863                context: buffer_snapshot.anchor_before(&range.context.start)
1864                    ..buffer_snapshot.anchor_after(&range.context.end),
1865                primary: buffer_snapshot.anchor_before(&range.primary.start)
1866                    ..buffer_snapshot.anchor_after(&range.primary.end),
1867            };
1868            excerpts.push((id, range.clone()));
1869            let excerpt = Excerpt::new(
1870                id,
1871                locator.clone(),
1872                buffer_id,
1873                buffer_snapshot.clone(),
1874                range,
1875                ranges.peek().is_some() || cursor.item().is_some(),
1876            );
1877            new_excerpts.push(excerpt, ());
1878            prev_locator = locator.clone();
1879
1880            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1881                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1882            }
1883            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1884        }
1885        snapshot
1886            .buffer_locators
1887            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1888
1889        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1890
1891        let suffix = cursor.suffix();
1892        let changed_trailing_excerpt = suffix.is_empty();
1893        new_excerpts.append(suffix, ());
1894        drop(cursor);
1895        snapshot.excerpts = new_excerpts;
1896        snapshot.excerpt_ids = new_excerpt_ids;
1897        if changed_trailing_excerpt {
1898            snapshot.trailing_excerpt_update_count += 1;
1899        }
1900
1901        let edits = Self::sync_diff_transforms(
1902            &mut snapshot,
1903            vec![Edit {
1904                old: edit_start..edit_start,
1905                new: edit_start..edit_end,
1906            }],
1907            DiffChangeKind::BufferEdited,
1908        );
1909        if !edits.is_empty() {
1910            self.subscriptions.publish(edits);
1911        }
1912
1913        cx.emit(Event::Edited {
1914            edited_buffer: None,
1915        });
1916        cx.emit(Event::ExcerptsAdded {
1917            buffer,
1918            predecessor: prev_excerpt_id,
1919            excerpts,
1920        });
1921        cx.notify();
1922    }
1923
1924    pub fn clear(&mut self, cx: &mut Context<Self>) {
1925        self.sync_mut(cx);
1926        let ids = self.excerpt_ids();
1927        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1928        self.excerpts_by_path.clear();
1929        self.paths_by_excerpt.clear();
1930        let MultiBufferSnapshot {
1931            excerpts,
1932            buffer_locators,
1933            diffs: _,
1934            diff_transforms: _,
1935            non_text_state_update_count: _,
1936            edit_count: _,
1937            is_dirty,
1938            has_deleted_file,
1939            has_conflict,
1940            has_inverted_diff,
1941            singleton: _,
1942            excerpt_ids: _,
1943            replaced_excerpts,
1944            trailing_excerpt_update_count,
1945            all_diff_hunks_expanded: _,
1946            show_deleted_hunks: _,
1947            use_extended_diff_range: _,
1948            show_headers: _,
1949        } = self.snapshot.get_mut();
1950        buffer_locators.clear();
1951        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1952        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1953        *excerpts = Default::default();
1954        *trailing_excerpt_update_count += 1;
1955        *is_dirty = false;
1956        *has_deleted_file = false;
1957        *has_conflict = false;
1958        *has_inverted_diff = false;
1959        match Arc::get_mut(replaced_excerpts) {
1960            Some(replaced_excerpts) => replaced_excerpts.clear(),
1961            None => *replaced_excerpts = Default::default(),
1962        }
1963
1964        let edits = Self::sync_diff_transforms(
1965            self.snapshot.get_mut(),
1966            vec![Edit {
1967                old: start..prev_len,
1968                new: start..start,
1969            }],
1970            DiffChangeKind::BufferEdited,
1971        );
1972        if !edits.is_empty() {
1973            self.subscriptions.publish(edits);
1974        }
1975        cx.emit(Event::Edited {
1976            edited_buffer: None,
1977        });
1978        cx.emit(Event::ExcerptsRemoved {
1979            ids,
1980            removed_buffer_ids,
1981        });
1982        cx.notify();
1983    }
1984
1985    #[ztracing::instrument(skip_all)]
1986    pub fn excerpts_for_buffer(
1987        &self,
1988        buffer_id: BufferId,
1989        cx: &App,
1990    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1991        let mut excerpts = Vec::new();
1992        let snapshot = self.read(cx);
1993        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1994        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1995            for locator in &**locators {
1996                cursor.seek_forward(&Some(locator), Bias::Left);
1997                if let Some(excerpt) = cursor.item()
1998                    && excerpt.locator == *locator
1999                {
2000                    excerpts.push((excerpt.id, excerpt.range.clone()));
2001                }
2002            }
2003        }
2004
2005        excerpts
2006    }
2007
2008    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2009        let snapshot = self.read(cx);
2010        let mut excerpts = snapshot
2011            .excerpts
2012            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2013        let mut diff_transforms = snapshot
2014            .diff_transforms
2015            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2016        diff_transforms.next();
2017        let locators = snapshot
2018            .buffer_locators
2019            .get(&buffer_id)
2020            .into_iter()
2021            .flat_map(|v| &**v);
2022        let mut result = Vec::new();
2023        for locator in locators {
2024            excerpts.seek_forward(&Some(locator), Bias::Left);
2025            if let Some(excerpt) = excerpts.item()
2026                && excerpt.locator == *locator
2027            {
2028                let excerpt_start = excerpts.start().1;
2029                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2030
2031                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2032                let overshoot = excerpt_start - diff_transforms.start().0;
2033                let start = diff_transforms.start().1 + overshoot;
2034
2035                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2036                let overshoot = excerpt_end - diff_transforms.start().0;
2037                let end = diff_transforms.start().1 + overshoot;
2038
2039                result.push(start.0..end.0)
2040            }
2041        }
2042        result
2043    }
2044
2045    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2046        self.snapshot
2047            .borrow()
2048            .excerpts
2049            .iter()
2050            .map(|entry| entry.buffer_id)
2051            .collect()
2052    }
2053
2054    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2055        let snapshot = self.snapshot.borrow();
2056        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2057        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2058        ids
2059    }
2060
2061    pub fn excerpt_containing(
2062        &self,
2063        position: impl ToOffset,
2064        cx: &App,
2065    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2066        let snapshot = self.read(cx);
2067        let offset = position.to_offset(&snapshot);
2068
2069        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2070        cursor.seek(&offset);
2071        cursor
2072            .excerpt()
2073            .or_else(|| snapshot.excerpts.last())
2074            .map(|excerpt| {
2075                (
2076                    excerpt.id,
2077                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2078                    excerpt.range.context.clone(),
2079                )
2080            })
2081    }
2082
2083    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2084        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2085            self.buffer(buffer_id)
2086        } else {
2087            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2088            Some(buffer)
2089        }
2090    }
2091
2092    // If point is at the end of the buffer, the last excerpt is returned
2093    pub fn point_to_buffer_offset<T: ToOffset>(
2094        &self,
2095        point: T,
2096        cx: &App,
2097    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2098        let snapshot = self.read(cx);
2099        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2100        Some((
2101            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2102            offset,
2103        ))
2104    }
2105
2106    // If point is at the end of the buffer, the last excerpt is returned
2107    pub fn point_to_buffer_point<T: ToPoint>(
2108        &self,
2109        point: T,
2110        cx: &App,
2111    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2112        let snapshot = self.read(cx);
2113        let (buffer, point, is_main_buffer) =
2114            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2115        Some((
2116            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2117            point,
2118            is_main_buffer,
2119        ))
2120    }
2121
2122    pub fn buffer_point_to_anchor(
2123        &self,
2124        // todo(lw): We shouldn't need this?
2125        buffer: &Entity<Buffer>,
2126        point: Point,
2127        cx: &App,
2128    ) -> Option<Anchor> {
2129        let mut found = None;
2130        let snapshot = buffer.read(cx).snapshot();
2131        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2132            let start = range.context.start.to_point(&snapshot);
2133            let end = range.context.end.to_point(&snapshot);
2134            if start <= point && point < end {
2135                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2136                break;
2137            }
2138            if point < start {
2139                found = Some((start, excerpt_id));
2140            }
2141            if point > end {
2142                found = Some((end, excerpt_id));
2143            }
2144        }
2145
2146        found.map(|(point, excerpt_id)| {
2147            let text_anchor = snapshot.anchor_after(point);
2148            Anchor::in_buffer(excerpt_id, text_anchor)
2149        })
2150    }
2151
2152    pub fn buffer_anchor_to_anchor(
2153        &self,
2154        // todo(lw): We shouldn't need this?
2155        buffer: &Entity<Buffer>,
2156        anchor: text::Anchor,
2157        cx: &App,
2158    ) -> Option<Anchor> {
2159        let snapshot = buffer.read(cx).snapshot();
2160        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2161            if range.context.start.cmp(&anchor, &snapshot).is_le()
2162                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2163            {
2164                return Some(Anchor::in_buffer(excerpt_id, anchor));
2165            }
2166        }
2167
2168        None
2169    }
2170
2171    pub fn merge_excerpts(
2172        &mut self,
2173        excerpt_ids: &[ExcerptId],
2174        cx: &mut Context<Self>,
2175    ) -> ExcerptId {
2176        debug_assert!(!excerpt_ids.is_empty());
2177        if excerpt_ids.len() == 1 {
2178            return excerpt_ids[0];
2179        }
2180
2181        let snapshot = self.snapshot(cx);
2182
2183        let first_range = snapshot
2184            .context_range_for_excerpt(excerpt_ids[0])
2185            .expect("first excerpt must exist");
2186        let last_range = snapshot
2187            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2188            .expect("last excerpt must exist");
2189
2190        let union_range = first_range.start..last_range.end;
2191
2192        drop(snapshot);
2193
2194        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2195        let removed = &excerpt_ids[1..];
2196        for &excerpt_id in removed {
2197            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2198                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2199                    excerpt_list.retain(|id| *id != excerpt_id);
2200                    if excerpt_list.is_empty() {
2201                        let path = path.clone();
2202                        self.excerpts_by_path.remove(&path);
2203                    }
2204                }
2205            }
2206        }
2207        self.remove_excerpts(removed.iter().copied(), cx);
2208
2209        excerpt_ids[0]
2210    }
2211
2212    pub fn remove_excerpts(
2213        &mut self,
2214        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2215        cx: &mut Context<Self>,
2216    ) {
2217        self.sync_mut(cx);
2218        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2219        if ids.is_empty() {
2220            return;
2221        }
2222        self.buffer_changed_since_sync.replace(true);
2223
2224        let mut snapshot = self.snapshot.get_mut();
2225        let mut new_excerpts = SumTree::default();
2226        let mut cursor = snapshot
2227            .excerpts
2228            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2229        let mut edits = Vec::new();
2230        let mut excerpt_ids = ids.iter().copied().peekable();
2231        let mut removed_buffer_ids = Vec::new();
2232        let mut removed_excerpts_for_buffers = HashSet::default();
2233
2234        while let Some(excerpt_id) = excerpt_ids.next() {
2235            self.paths_by_excerpt.remove(&excerpt_id);
2236            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2237            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2238            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2239
2240            if let Some(mut excerpt) = cursor.item() {
2241                if excerpt.id != excerpt_id {
2242                    continue;
2243                }
2244                let mut old_start = cursor.start().1;
2245
2246                // Skip over the removed excerpt.
2247                'remove_excerpts: loop {
2248                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2249                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2250                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2251                        if buffer_state.excerpts.is_empty() {
2252                            log::debug!(
2253                                "removing buffer and diff for buffer {}",
2254                                excerpt.buffer_id
2255                            );
2256                            self.buffers.remove(&excerpt.buffer_id);
2257                            removed_buffer_ids.push(excerpt.buffer_id);
2258                        }
2259                    }
2260                    cursor.next();
2261
2262                    // Skip over any subsequent excerpts that are also removed.
2263                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2264                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2265                        if let Some(next_excerpt) = cursor.item()
2266                            && next_excerpt.locator == *next_locator
2267                        {
2268                            excerpt_ids.next();
2269                            excerpt = next_excerpt;
2270                            continue 'remove_excerpts;
2271                        }
2272                    }
2273
2274                    break;
2275                }
2276
2277                // When removing the last excerpt, remove the trailing newline from
2278                // the previous excerpt.
2279                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2280                    old_start -= 1;
2281                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2282                }
2283
2284                // Push an edit for the removal of this run of excerpts.
2285                let old_end = cursor.start().1;
2286                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2287                edits.push(Edit {
2288                    old: old_start..old_end,
2289                    new: new_start..new_start,
2290                });
2291            }
2292        }
2293        let suffix = cursor.suffix();
2294        let changed_trailing_excerpt = suffix.is_empty();
2295        new_excerpts.append(suffix, ());
2296        drop(cursor);
2297        for buffer_id in removed_excerpts_for_buffers {
2298            match self.buffers.get(&buffer_id) {
2299                Some(buffer_state) => {
2300                    snapshot
2301                        .buffer_locators
2302                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2303                }
2304                None => {
2305                    snapshot.buffer_locators.remove(&buffer_id);
2306                }
2307            }
2308        }
2309        snapshot.excerpts = new_excerpts;
2310        for buffer_id in &removed_buffer_ids {
2311            self.diffs.remove(buffer_id);
2312            snapshot.diffs.remove(buffer_id);
2313        }
2314
2315        // Recalculate has_inverted_diff after removing diffs
2316        if !removed_buffer_ids.is_empty() {
2317            snapshot.has_inverted_diff = snapshot
2318                .diffs
2319                .iter()
2320                .any(|(_, diff)| diff.main_buffer.is_some());
2321        }
2322
2323        if changed_trailing_excerpt {
2324            snapshot.trailing_excerpt_update_count += 1;
2325        }
2326
2327        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2328        if !edits.is_empty() {
2329            self.subscriptions.publish(edits);
2330        }
2331        cx.emit(Event::Edited {
2332            edited_buffer: None,
2333        });
2334        cx.emit(Event::ExcerptsRemoved {
2335            ids,
2336            removed_buffer_ids,
2337        });
2338        cx.notify();
2339    }
2340
2341    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2342        &self,
2343        anchors: Anchors,
2344        cx: &mut Context<Self>,
2345    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2346        let mut error = None;
2347        let mut futures = Vec::new();
2348        for anchor in anchors {
2349            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2350                if let Some(buffer) = self.buffers.get(&buffer_id) {
2351                    buffer.buffer.update(cx, |buffer, _| {
2352                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2353                    });
2354                } else {
2355                    error = Some(anyhow!(
2356                        "buffer {buffer_id} is not part of this multi-buffer"
2357                    ));
2358                    break;
2359                }
2360            }
2361        }
2362        async move {
2363            if let Some(error) = error {
2364                Err(error)?;
2365            }
2366            for future in futures {
2367                future.await?;
2368            }
2369            Ok(())
2370        }
2371    }
2372
2373    pub fn text_anchor_for_position<T: ToOffset>(
2374        &self,
2375        position: T,
2376        cx: &App,
2377    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2378        let snapshot = self.read(cx);
2379        let anchor = snapshot.anchor_before(position);
2380        let buffer = self
2381            .buffers
2382            .get(&anchor.text_anchor.buffer_id?)?
2383            .buffer
2384            .clone();
2385        Some((buffer, anchor.text_anchor))
2386    }
2387
2388    fn on_buffer_event(
2389        &mut self,
2390        buffer: Entity<Buffer>,
2391        event: &language::BufferEvent,
2392        cx: &mut Context<Self>,
2393    ) {
2394        use language::BufferEvent;
2395        let buffer_id = buffer.read(cx).remote_id();
2396        cx.emit(match event {
2397            BufferEvent::Edited => Event::Edited {
2398                edited_buffer: Some(buffer),
2399            },
2400            BufferEvent::DirtyChanged => Event::DirtyChanged,
2401            BufferEvent::Saved => Event::Saved,
2402            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2403            BufferEvent::Reloaded => Event::Reloaded,
2404            BufferEvent::LanguageChanged(has_language) => {
2405                Event::LanguageChanged(buffer_id, *has_language)
2406            }
2407            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2408            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2409            BufferEvent::CapabilityChanged => {
2410                self.capability = buffer.read(cx).capability();
2411                return;
2412            }
2413            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2414        });
2415    }
2416
2417    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2418        let diff = diff.read(cx);
2419        let buffer_id = diff.buffer_id;
2420        let diff = DiffStateSnapshot {
2421            diff: diff.snapshot(cx),
2422            main_buffer: None,
2423        };
2424        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2425    }
2426
2427    fn inverted_buffer_diff_language_changed(
2428        &mut self,
2429        diff: Entity<BufferDiff>,
2430        main_buffer: Entity<language::Buffer>,
2431        cx: &mut Context<Self>,
2432    ) {
2433        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2434        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2435        let diff = diff.read(cx);
2436        let diff = DiffStateSnapshot {
2437            diff: diff.snapshot(cx),
2438            main_buffer: Some(main_buffer_snapshot),
2439        };
2440        self.snapshot
2441            .get_mut()
2442            .diffs
2443            .insert(base_text_buffer_id, diff);
2444    }
2445
2446    fn buffer_diff_changed(
2447        &mut self,
2448        diff: Entity<BufferDiff>,
2449        range: Range<text::Anchor>,
2450        cx: &mut Context<Self>,
2451    ) {
2452        self.sync_mut(cx);
2453
2454        let diff = diff.read(cx);
2455        let buffer_id = diff.buffer_id;
2456
2457        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2458            return;
2459        };
2460        let new_diff = DiffStateSnapshot {
2461            diff: diff.snapshot(cx),
2462            main_buffer: None,
2463        };
2464        let mut snapshot = self.snapshot.get_mut();
2465        let base_text_changed = snapshot
2466            .diffs
2467            .get(&buffer_id)
2468            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2469        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2470
2471        let buffer = buffer_state.buffer.read(cx);
2472        let diff_change_range = range.to_offset(buffer);
2473
2474        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2475        let edits = Self::sync_diff_transforms(
2476            &mut snapshot,
2477            excerpt_edits,
2478            DiffChangeKind::DiffUpdated {
2479                base_changed: base_text_changed,
2480            },
2481        );
2482        if !edits.is_empty() {
2483            self.subscriptions.publish(edits);
2484        }
2485        cx.emit(Event::Edited {
2486            edited_buffer: None,
2487        });
2488    }
2489
2490    fn inverted_buffer_diff_changed(
2491        &mut self,
2492        diff: Entity<BufferDiff>,
2493        main_buffer: Entity<language::Buffer>,
2494        diff_change_range: Option<Range<usize>>,
2495        cx: &mut Context<Self>,
2496    ) {
2497        self.sync_mut(cx);
2498
2499        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2500        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2501            return;
2502        };
2503
2504        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2505        let diff = diff.read(cx);
2506        let new_diff = DiffStateSnapshot {
2507            diff: diff.snapshot(cx),
2508            main_buffer: Some(main_buffer_snapshot),
2509        };
2510        let mut snapshot = self.snapshot.get_mut();
2511        snapshot
2512            .diffs
2513            .insert_or_replace(base_text_buffer_id, new_diff);
2514
2515        let Some(diff_change_range) = diff_change_range else {
2516            return;
2517        };
2518
2519        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2520        let edits = Self::sync_diff_transforms(
2521            &mut snapshot,
2522            excerpt_edits,
2523            DiffChangeKind::DiffUpdated {
2524                // We don't read this field for inverted diffs.
2525                base_changed: false,
2526            },
2527        );
2528        if !edits.is_empty() {
2529            self.subscriptions.publish(edits);
2530        }
2531        cx.emit(Event::Edited {
2532            edited_buffer: None,
2533        });
2534    }
2535
2536    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2537        self.buffers.values().map(|state| state.buffer.clone())
2538    }
2539
2540    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2541        self.all_buffers_iter().collect()
2542    }
2543
2544    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2545        self.buffers.keys().copied()
2546    }
2547
2548    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2549        self.all_buffer_ids_iter().collect()
2550    }
2551
2552    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2553        self.buffers
2554            .get(&buffer_id)
2555            .map(|state| state.buffer.clone())
2556    }
2557
2558    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2559        self.point_to_buffer_offset(point, cx)
2560            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2561    }
2562
2563    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2564        let buffer_id = self
2565            .snapshot
2566            .borrow()
2567            .excerpts
2568            .first()
2569            .map(|excerpt| excerpt.buffer.remote_id());
2570        buffer_id
2571            .and_then(|buffer_id| self.buffer(buffer_id))
2572            .map(|buffer| {
2573                let buffer = buffer.read(cx);
2574                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2575            })
2576            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2577    }
2578
2579    pub fn language_settings_at<'a, T: ToOffset>(
2580        &'a self,
2581        point: T,
2582        cx: &'a App,
2583    ) -> Cow<'a, LanguageSettings> {
2584        let mut language = None;
2585        let mut file = None;
2586        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2587            let buffer = buffer.read(cx);
2588            language = buffer.language_at(offset);
2589            file = buffer.file();
2590        }
2591        language_settings(language.map(|l| l.name()), file, cx)
2592    }
2593
2594    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2595        self.buffers.values().for_each(|state| f(&state.buffer))
2596    }
2597
2598    pub fn explicit_title(&self) -> Option<&str> {
2599        self.title.as_deref()
2600    }
2601
2602    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2603        if let Some(title) = self.title.as_ref() {
2604            return title.into();
2605        }
2606
2607        if let Some(buffer) = self.as_singleton() {
2608            let buffer = buffer.read(cx);
2609
2610            if let Some(file) = buffer.file() {
2611                return file.file_name(cx).into();
2612            }
2613
2614            if let Some(title) = self.buffer_content_title(buffer) {
2615                return title;
2616            }
2617        };
2618
2619        "untitled".into()
2620    }
2621
2622    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2623        let mut is_leading_whitespace = true;
2624        let mut count = 0;
2625        let mut prev_was_space = false;
2626        let mut title = String::new();
2627
2628        for ch in buffer.snapshot().chars() {
2629            if is_leading_whitespace && ch.is_whitespace() {
2630                continue;
2631            }
2632
2633            is_leading_whitespace = false;
2634
2635            if ch == '\n' || count >= 40 {
2636                break;
2637            }
2638
2639            if ch.is_whitespace() {
2640                if !prev_was_space {
2641                    title.push(' ');
2642                    count += 1;
2643                    prev_was_space = true;
2644                }
2645            } else {
2646                title.push(ch);
2647                count += 1;
2648                prev_was_space = false;
2649            }
2650        }
2651
2652        let title = title.trim_end().to_string();
2653
2654        if title.is_empty() {
2655            return None;
2656        }
2657
2658        Some(title.into())
2659    }
2660
2661    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2662        self.title = Some(title);
2663        cx.notify();
2664    }
2665
2666    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2667    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2668        for buffer_state in self.buffers.values() {
2669            buffer_state
2670                .buffer
2671                .update(cx, |buffer, _cx| buffer.refresh_preview());
2672        }
2673    }
2674
2675    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2676    pub fn preserve_preview(&self, cx: &App) -> bool {
2677        self.buffers
2678            .values()
2679            .all(|state| state.buffer.read(cx).preserve_preview())
2680    }
2681
2682    #[cfg(any(test, feature = "test-support"))]
2683    pub fn is_parsing(&self, cx: &App) -> bool {
2684        self.as_singleton().unwrap().read(cx).is_parsing()
2685    }
2686
2687    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2688        let buffer_id = diff.read(cx).buffer_id;
2689
2690        if let Some(existing_diff) = self.diff_for(buffer_id)
2691            && diff.entity_id() == existing_diff.entity_id()
2692        {
2693            return;
2694        }
2695
2696        self.buffer_diff_changed(
2697            diff.clone(),
2698            text::Anchor::min_max_range_for_buffer(buffer_id),
2699            cx,
2700        );
2701        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2702    }
2703
2704    pub fn add_inverted_diff(
2705        &mut self,
2706        diff: Entity<BufferDiff>,
2707        main_buffer: Entity<language::Buffer>,
2708        cx: &mut Context<Self>,
2709    ) {
2710        let snapshot = diff.read(cx).base_text(cx);
2711        let base_text_buffer_id = snapshot.remote_id();
2712        let diff_change_range = 0..snapshot.len();
2713        self.snapshot.get_mut().has_inverted_diff = true;
2714        self.inverted_buffer_diff_changed(
2715            diff.clone(),
2716            main_buffer.clone(),
2717            Some(diff_change_range),
2718            cx,
2719        );
2720        self.diffs.insert(
2721            base_text_buffer_id,
2722            DiffState::new_inverted(diff, main_buffer, cx),
2723        );
2724    }
2725
2726    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2727        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2728    }
2729
2730    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2731        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2732    }
2733
2734    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2735        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2736    }
2737
2738    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2739        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2740        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2741    }
2742
2743    pub fn all_diff_hunks_expanded(&self) -> bool {
2744        self.snapshot.borrow().all_diff_hunks_expanded
2745    }
2746
2747    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2748        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2749        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2750    }
2751
2752    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2753        self.snapshot.get_mut().show_deleted_hunks = show;
2754
2755        self.sync_mut(cx);
2756
2757        let old_len = self.snapshot.borrow().len();
2758
2759        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2760        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2761
2762        let new_len = self.snapshot.borrow().len();
2763
2764        self.subscriptions.publish(vec![Edit {
2765            old: MultiBufferOffset(0)..old_len,
2766            new: MultiBufferOffset(0)..new_len,
2767        }]);
2768
2769        cx.emit(Event::DiffHunksToggled);
2770        cx.emit(Event::Edited {
2771            edited_buffer: None,
2772        });
2773    }
2774
2775    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2776        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2777    }
2778
2779    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2780        self.read(cx)
2781            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2782            .nth(1)
2783            .is_some()
2784    }
2785
2786    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2787        let snapshot = self.read(cx);
2788        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2789        let offset_range = range.to_offset(&snapshot);
2790        cursor.seek(&offset_range.start, Bias::Left);
2791        while let Some(item) = cursor.item() {
2792            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2793                break;
2794            }
2795            if item.hunk_info().is_some() {
2796                return true;
2797            }
2798            cursor.next();
2799        }
2800        false
2801    }
2802
2803    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2804        let snapshot = self.read(cx);
2805        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2806        for range in ranges {
2807            let range = range.to_point(&snapshot);
2808            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2809            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2810                .min(snapshot.len());
2811            cursor.seek(&start, Bias::Right);
2812            while let Some(item) = cursor.item() {
2813                if *cursor.start() >= end {
2814                    break;
2815                }
2816                if item.hunk_info().is_some() {
2817                    return true;
2818                }
2819                cursor.next();
2820            }
2821        }
2822        false
2823    }
2824
2825    pub fn expand_or_collapse_diff_hunks_inner(
2826        &mut self,
2827        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2828        expand: bool,
2829        cx: &mut Context<Self>,
2830    ) -> Vec<Edit<MultiBufferOffset>> {
2831        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2832            return Vec::new();
2833        }
2834        self.sync_mut(cx);
2835        let mut snapshot = self.snapshot.get_mut();
2836        let mut excerpt_edits = Vec::new();
2837        let mut last_hunk_row = None;
2838        for (range, end_excerpt_id) in ranges {
2839            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2840                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2841                    continue;
2842                }
2843                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2844                    continue;
2845                }
2846                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2847                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2848                let start = snapshot.excerpt_offset_for_anchor(&start);
2849                let end = snapshot.excerpt_offset_for_anchor(&end);
2850                last_hunk_row = Some(diff_hunk.row_range.start);
2851                excerpt_edits.push(text::Edit {
2852                    old: start..end,
2853                    new: start..end,
2854                });
2855            }
2856        }
2857
2858        Self::sync_diff_transforms(
2859            &mut snapshot,
2860            excerpt_edits,
2861            DiffChangeKind::ExpandOrCollapseHunks { expand },
2862        )
2863    }
2864
2865    pub fn expand_or_collapse_diff_hunks(
2866        &mut self,
2867        ranges: Vec<Range<Anchor>>,
2868        expand: bool,
2869        cx: &mut Context<Self>,
2870    ) {
2871        let snapshot = self.snapshot.borrow().clone();
2872        let ranges = ranges.iter().map(move |range| {
2873            let end_excerpt_id = range.end.excerpt_id;
2874            let range = range.to_point(&snapshot);
2875            let mut peek_end = range.end;
2876            if range.end.row < snapshot.max_row().0 {
2877                peek_end = Point::new(range.end.row + 1, 0);
2878            };
2879            (range.start..peek_end, end_excerpt_id)
2880        });
2881        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2882        if !edits.is_empty() {
2883            self.subscriptions.publish(edits);
2884        }
2885        cx.emit(Event::DiffHunksToggled);
2886        cx.emit(Event::Edited {
2887            edited_buffer: None,
2888        });
2889    }
2890
2891    pub fn resize_excerpt(
2892        &mut self,
2893        id: ExcerptId,
2894        range: Range<text::Anchor>,
2895        cx: &mut Context<Self>,
2896    ) {
2897        self.sync_mut(cx);
2898
2899        let mut snapshot = self.snapshot.get_mut();
2900        let locator = snapshot.excerpt_locator_for_id(id);
2901        let mut new_excerpts = SumTree::default();
2902        let mut cursor = snapshot
2903            .excerpts
2904            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2905        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2906
2907        let prefix = cursor.slice(&Some(locator), Bias::Left);
2908        new_excerpts.append(prefix, ());
2909
2910        let mut excerpt = cursor.item().unwrap().clone();
2911        let old_text_len = excerpt.text_summary.len;
2912
2913        excerpt.range.context.start = range.start;
2914        excerpt.range.context.end = range.end;
2915        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2916
2917        excerpt.text_summary = excerpt
2918            .buffer
2919            .text_summary_for_range(excerpt.range.context.clone());
2920
2921        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2922        let old_start_offset = cursor.start().1;
2923        let new_text_len = excerpt.text_summary.len;
2924        let edit = Edit {
2925            old: old_start_offset..old_start_offset + old_text_len,
2926            new: new_start_offset..new_start_offset + new_text_len,
2927        };
2928
2929        if let Some(last_edit) = edits.last_mut() {
2930            if last_edit.old.end == edit.old.start {
2931                last_edit.old.end = edit.old.end;
2932                last_edit.new.end = edit.new.end;
2933            } else {
2934                edits.push(edit);
2935            }
2936        } else {
2937            edits.push(edit);
2938        }
2939
2940        new_excerpts.push(excerpt, ());
2941
2942        cursor.next();
2943
2944        new_excerpts.append(cursor.suffix(), ());
2945
2946        drop(cursor);
2947        snapshot.excerpts = new_excerpts;
2948
2949        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2950        if !edits.is_empty() {
2951            self.subscriptions.publish(edits);
2952        }
2953        cx.emit(Event::Edited {
2954            edited_buffer: None,
2955        });
2956        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2957        cx.notify();
2958    }
2959
2960    pub fn expand_excerpts(
2961        &mut self,
2962        ids: impl IntoIterator<Item = ExcerptId>,
2963        line_count: u32,
2964        direction: ExpandExcerptDirection,
2965        cx: &mut Context<Self>,
2966    ) {
2967        if line_count == 0 {
2968            return;
2969        }
2970        self.sync_mut(cx);
2971        if !self.excerpts_by_path.is_empty() {
2972            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2973            return;
2974        }
2975        let mut snapshot = self.snapshot.get_mut();
2976
2977        let ids = ids.into_iter().collect::<Vec<_>>();
2978        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2979        let mut new_excerpts = SumTree::default();
2980        let mut cursor = snapshot
2981            .excerpts
2982            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2983        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2984
2985        for locator in &locators {
2986            let prefix = cursor.slice(&Some(locator), Bias::Left);
2987            new_excerpts.append(prefix, ());
2988
2989            let mut excerpt = cursor.item().unwrap().clone();
2990            let old_text_len = excerpt.text_summary.len;
2991
2992            let up_line_count = if direction.should_expand_up() {
2993                line_count
2994            } else {
2995                0
2996            };
2997
2998            let start_row = excerpt
2999                .range
3000                .context
3001                .start
3002                .to_point(&excerpt.buffer)
3003                .row
3004                .saturating_sub(up_line_count);
3005            let start_point = Point::new(start_row, 0);
3006            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3007
3008            let down_line_count = if direction.should_expand_down() {
3009                line_count
3010            } else {
3011                0
3012            };
3013
3014            let mut end_point = excerpt.buffer.clip_point(
3015                excerpt.range.context.end.to_point(&excerpt.buffer)
3016                    + Point::new(down_line_count, 0),
3017                Bias::Left,
3018            );
3019            end_point.column = excerpt.buffer.line_len(end_point.row);
3020            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3021            excerpt.max_buffer_row = end_point.row;
3022
3023            excerpt.text_summary = excerpt
3024                .buffer
3025                .text_summary_for_range(excerpt.range.context.clone());
3026
3027            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3028            let old_start_offset = cursor.start().1;
3029            let new_text_len = excerpt.text_summary.len;
3030            let edit = Edit {
3031                old: old_start_offset..old_start_offset + old_text_len,
3032                new: new_start_offset..new_start_offset + new_text_len,
3033            };
3034
3035            if let Some(last_edit) = edits.last_mut() {
3036                if last_edit.old.end == edit.old.start {
3037                    last_edit.old.end = edit.old.end;
3038                    last_edit.new.end = edit.new.end;
3039                } else {
3040                    edits.push(edit);
3041                }
3042            } else {
3043                edits.push(edit);
3044            }
3045
3046            new_excerpts.push(excerpt, ());
3047
3048            cursor.next();
3049        }
3050
3051        new_excerpts.append(cursor.suffix(), ());
3052
3053        drop(cursor);
3054        snapshot.excerpts = new_excerpts;
3055
3056        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3057        if !edits.is_empty() {
3058            self.subscriptions.publish(edits);
3059        }
3060        cx.emit(Event::Edited {
3061            edited_buffer: None,
3062        });
3063        cx.emit(Event::ExcerptsExpanded { ids });
3064        cx.notify();
3065    }
3066
3067    #[ztracing::instrument(skip_all)]
3068    fn sync(&self, cx: &App) {
3069        let changed = self.buffer_changed_since_sync.replace(false);
3070        if !changed {
3071            return;
3072        }
3073        let edits = Self::sync_from_buffer_changes(
3074            &mut self.snapshot.borrow_mut(),
3075            &self.buffers,
3076            &self.diffs,
3077            cx,
3078        );
3079        if !edits.is_empty() {
3080            self.subscriptions.publish(edits);
3081        }
3082    }
3083
3084    fn sync_mut(&mut self, cx: &App) {
3085        let changed = self.buffer_changed_since_sync.replace(false);
3086        if !changed {
3087            return;
3088        }
3089        let edits =
3090            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3091
3092        if !edits.is_empty() {
3093            self.subscriptions.publish(edits);
3094        }
3095    }
3096
3097    fn sync_from_buffer_changes(
3098        snapshot: &mut MultiBufferSnapshot,
3099        buffers: &BTreeMap<BufferId, BufferState>,
3100        diffs: &HashMap<BufferId, DiffState>,
3101        cx: &App,
3102    ) -> Vec<Edit<MultiBufferOffset>> {
3103        let MultiBufferSnapshot {
3104            excerpts,
3105            buffer_locators: _,
3106            diffs: buffer_diff,
3107            diff_transforms: _,
3108            non_text_state_update_count,
3109            edit_count,
3110            is_dirty,
3111            has_deleted_file,
3112            has_conflict,
3113            has_inverted_diff: _,
3114            singleton: _,
3115            excerpt_ids: _,
3116            replaced_excerpts: _,
3117            trailing_excerpt_update_count: _,
3118            all_diff_hunks_expanded: _,
3119            show_deleted_hunks: _,
3120            use_extended_diff_range: _,
3121            show_headers: _,
3122        } = snapshot;
3123        *is_dirty = false;
3124        *has_deleted_file = false;
3125        *has_conflict = false;
3126
3127        if !diffs.is_empty() {
3128            let mut diffs_to_add = Vec::new();
3129            for (id, diff) in diffs {
3130                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3131                // and use the diff hunk base text ranges to compute diff transforms.
3132                // Those base text ranges are usize, so make sure if the base text changed
3133                // we also update the diff snapshot so that we don't use stale offsets
3134                if buffer_diff.get(id).is_none_or(|existing_diff| {
3135                    if existing_diff.main_buffer.is_none() {
3136                        return false;
3137                    }
3138                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3139                    base_text.remote_id() != existing_diff.base_text().remote_id()
3140                        || base_text
3141                            .version()
3142                            .changed_since(existing_diff.base_text().version())
3143                }) {
3144                    if diffs_to_add.capacity() == 0 {
3145                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3146                        // meaning re-allocations will be fairly expensive
3147                        diffs_to_add.reserve(diffs.len());
3148                    }
3149                    diffs_to_add.push((*id, diff.snapshot(cx)));
3150                }
3151            }
3152            buffer_diff.extend(diffs_to_add);
3153        }
3154
3155        let mut excerpts_to_edit = Vec::new();
3156        let mut non_text_state_updated = false;
3157        let mut edited = false;
3158        for buffer_state in buffers.values() {
3159            let buffer = buffer_state.buffer.read(cx);
3160            let version = buffer.version();
3161            let non_text_state_update_count = buffer.non_text_state_update_count();
3162
3163            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3164            let buffer_non_text_state_updated =
3165                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3166            if buffer_edited || buffer_non_text_state_updated {
3167                *buffer_state.last_version.borrow_mut() = version;
3168                buffer_state
3169                    .last_non_text_state_update_count
3170                    .set(non_text_state_update_count);
3171                excerpts_to_edit.extend(
3172                    buffer_state
3173                        .excerpts
3174                        .iter()
3175                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3176                );
3177            }
3178
3179            edited |= buffer_edited;
3180            non_text_state_updated |= buffer_non_text_state_updated;
3181            *is_dirty |= buffer.is_dirty();
3182            *has_deleted_file |= buffer
3183                .file()
3184                .is_some_and(|file| file.disk_state().is_deleted());
3185            *has_conflict |= buffer.has_conflict();
3186        }
3187        if edited {
3188            *edit_count += 1;
3189        }
3190        if non_text_state_updated {
3191            *non_text_state_update_count += 1;
3192        }
3193
3194        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3195
3196        let mut edits = Vec::new();
3197        let mut new_excerpts = SumTree::default();
3198        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3199
3200        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3201            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3202            let old_excerpt = cursor.item().unwrap();
3203            let buffer = buffer.read(cx);
3204            let buffer_id = buffer.remote_id();
3205            let mut new_excerpt;
3206            if buffer_edited {
3207                edits.extend(
3208                    buffer
3209                        .edits_since_in_range::<usize>(
3210                            old_excerpt.buffer.version(),
3211                            old_excerpt.range.context.clone(),
3212                        )
3213                        .map(|edit| {
3214                            let excerpt_old_start = cursor.start().1;
3215                            let excerpt_new_start =
3216                                ExcerptDimension(new_excerpts.summary().text.len);
3217                            let old_start = excerpt_old_start + edit.old.start;
3218                            let old_end = excerpt_old_start + edit.old.end;
3219                            let new_start = excerpt_new_start + edit.new.start;
3220                            let new_end = excerpt_new_start + edit.new.end;
3221                            Edit {
3222                                old: old_start..old_end,
3223                                new: new_start..new_end,
3224                            }
3225                        }),
3226                );
3227
3228                new_excerpt = Excerpt::new(
3229                    old_excerpt.id,
3230                    locator.clone(),
3231                    buffer_id,
3232                    Arc::new(buffer.snapshot()),
3233                    old_excerpt.range.clone(),
3234                    old_excerpt.has_trailing_newline,
3235                );
3236            } else {
3237                new_excerpt = old_excerpt.clone();
3238                new_excerpt.buffer = Arc::new(buffer.snapshot());
3239            }
3240
3241            new_excerpts.push(new_excerpt, ());
3242            cursor.next();
3243        }
3244        new_excerpts.append(cursor.suffix(), ());
3245
3246        drop(cursor);
3247        *excerpts = new_excerpts;
3248
3249        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3250    }
3251
3252    fn sync_diff_transforms(
3253        snapshot: &mut MultiBufferSnapshot,
3254        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3255        change_kind: DiffChangeKind,
3256    ) -> Vec<Edit<MultiBufferOffset>> {
3257        if excerpt_edits.is_empty() {
3258            return vec![];
3259        }
3260
3261        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3262        let mut old_diff_transforms = snapshot
3263            .diff_transforms
3264            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3265        let mut new_diff_transforms = SumTree::default();
3266        let mut old_expanded_hunks = HashSet::default();
3267        let mut output_edits = Vec::new();
3268        let mut output_delta = 0_isize;
3269        let mut at_transform_boundary = true;
3270        let mut end_of_current_insert = None;
3271
3272        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3273        while let Some(edit) = excerpt_edits.next() {
3274            excerpts.seek_forward(&edit.new.start, Bias::Right);
3275            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3276                excerpts.prev();
3277            }
3278
3279            // Keep any transforms that are before the edit.
3280            if at_transform_boundary {
3281                at_transform_boundary = false;
3282                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3283                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3284                if let Some(transform) = old_diff_transforms.item()
3285                    && old_diff_transforms.end().0 == edit.old.start
3286                    && old_diff_transforms.start().0 < edit.old.start
3287                {
3288                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3289                    old_diff_transforms.next();
3290                }
3291            }
3292
3293            // Compute the start of the edit in output coordinates.
3294            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3295            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3296            let edit_new_start =
3297                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3298
3299            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3300                &edit,
3301                &mut excerpts,
3302                &mut old_diff_transforms,
3303                &mut new_diff_transforms,
3304                &mut end_of_current_insert,
3305                &mut old_expanded_hunks,
3306                snapshot,
3307                change_kind,
3308            );
3309
3310            // Compute the end of the edit in output coordinates.
3311            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3312            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3313            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3314            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3315            let output_edit = Edit {
3316                old: edit_old_start..edit_old_end,
3317                new: edit_new_start..edit_new_end,
3318            };
3319
3320            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3321            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3322            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3323                output_edits.push(output_edit);
3324            }
3325
3326            // If this is the last edit that intersects the current diff transform,
3327            // then recreate the content up to the end of this transform, to prepare
3328            // for reusing additional slices of the old transforms.
3329            if excerpt_edits
3330                .peek()
3331                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3332            {
3333                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3334                    && match old_diff_transforms.item() {
3335                        Some(DiffTransform::BufferContent {
3336                            inserted_hunk_info: Some(hunk),
3337                            ..
3338                        }) => excerpts.item().is_some_and(|excerpt| {
3339                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3340                                && diff.main_buffer.is_some()
3341                            {
3342                                return true;
3343                            }
3344                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3345                        }),
3346                        _ => true,
3347                    };
3348
3349                let mut excerpt_offset = edit.new.end;
3350                if !keep_next_old_transform {
3351                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3352                    old_diff_transforms.next();
3353                }
3354
3355                old_expanded_hunks.clear();
3356                Self::push_buffer_content_transform(
3357                    snapshot,
3358                    &mut new_diff_transforms,
3359                    excerpt_offset,
3360                    end_of_current_insert,
3361                );
3362                at_transform_boundary = true;
3363            }
3364        }
3365
3366        // Keep any transforms that are after the last edit.
3367        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3368
3369        // Ensure there's always at least one buffer content transform.
3370        if new_diff_transforms.is_empty() {
3371            new_diff_transforms.push(
3372                DiffTransform::BufferContent {
3373                    summary: Default::default(),
3374                    inserted_hunk_info: None,
3375                },
3376                (),
3377            );
3378        }
3379
3380        drop(old_diff_transforms);
3381        drop(excerpts);
3382        snapshot.diff_transforms = new_diff_transforms;
3383        snapshot.edit_count += 1;
3384
3385        #[cfg(any(test, feature = "test-support"))]
3386        snapshot.check_invariants();
3387        output_edits
3388    }
3389
3390    fn recompute_diff_transforms_for_edit(
3391        edit: &Edit<ExcerptOffset>,
3392        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3393        old_diff_transforms: &mut Cursor<
3394            DiffTransform,
3395            Dimensions<ExcerptOffset, MultiBufferOffset>,
3396        >,
3397        new_diff_transforms: &mut SumTree<DiffTransform>,
3398        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3399        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3400        snapshot: &MultiBufferSnapshot,
3401        change_kind: DiffChangeKind,
3402    ) -> bool {
3403        log::trace!(
3404            "recomputing diff transform for edit {:?} => {:?}",
3405            edit.old.start..edit.old.end,
3406            edit.new.start..edit.new.end
3407        );
3408
3409        // Record which hunks were previously expanded.
3410        while let Some(item) = old_diff_transforms.item() {
3411            if let Some(hunk_info) = item.hunk_info() {
3412                log::trace!(
3413                    "previously expanded hunk at {:?}",
3414                    old_diff_transforms.start()
3415                );
3416                old_expanded_hunks.insert(hunk_info);
3417            }
3418            if old_diff_transforms.end().0 > edit.old.end {
3419                break;
3420            }
3421            old_diff_transforms.next();
3422        }
3423
3424        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3425        // For inverted diffs, hunks are always shown, so we can't skip this.
3426        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3427        if old_expanded_hunks.is_empty()
3428            && change_kind == DiffChangeKind::BufferEdited
3429            && !all_diff_hunks_expanded
3430            && !snapshot.has_inverted_diff
3431        {
3432            return false;
3433        }
3434
3435        // Visit each excerpt that intersects the edit.
3436        let mut did_expand_hunks = false;
3437        while let Some(excerpt) = excerpts.item() {
3438            // Recompute the expanded hunks in the portion of the excerpt that
3439            // intersects the edit.
3440            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3441                let buffer = &excerpt.buffer;
3442                let excerpt_start = *excerpts.start();
3443                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3444                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3445                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3446                let edit_buffer_start =
3447                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3448                let edit_buffer_end =
3449                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3450                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3451
3452                if let Some(main_buffer) = &diff.main_buffer {
3453                    for hunk in diff.hunks_intersecting_base_text_range(
3454                        edit_buffer_start..edit_buffer_end,
3455                        main_buffer,
3456                    ) {
3457                        did_expand_hunks = true;
3458                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3459                        if hunk_buffer_range.start < excerpt_buffer_start {
3460                            log::trace!("skipping hunk that starts before excerpt");
3461                            continue;
3462                        }
3463                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3464                        let hunk_excerpt_start = excerpt_start
3465                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3466                        let hunk_excerpt_end = excerpt_end
3467                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3468                        Self::push_buffer_content_transform(
3469                            snapshot,
3470                            new_diff_transforms,
3471                            hunk_excerpt_start,
3472                            *end_of_current_insert,
3473                        );
3474                        if !hunk_buffer_range.is_empty() {
3475                            let hunk_info = DiffTransformHunkInfo {
3476                                excerpt_id: excerpt.id,
3477                                hunk_start_anchor: hunk.buffer_range.start,
3478                                hunk_secondary_status: hunk.secondary_status,
3479                                is_logically_deleted: true,
3480                            };
3481                            *end_of_current_insert =
3482                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3483                        }
3484                    }
3485                } else {
3486                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3487                        ..buffer.anchor_after(edit_buffer_end);
3488                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3489                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3490                            continue;
3491                        }
3492
3493                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3494                        if hunk_buffer_range.start < excerpt_buffer_start {
3495                            log::trace!("skipping hunk that starts before excerpt");
3496                            continue;
3497                        }
3498
3499                        let hunk_info = DiffTransformHunkInfo {
3500                            excerpt_id: excerpt.id,
3501                            hunk_start_anchor: hunk.buffer_range.start,
3502                            hunk_secondary_status: hunk.secondary_status,
3503                            is_logically_deleted: false,
3504                        };
3505
3506                        let hunk_excerpt_start = excerpt_start
3507                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3508                        let hunk_excerpt_end = excerpt_end
3509                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3510
3511                        Self::push_buffer_content_transform(
3512                            snapshot,
3513                            new_diff_transforms,
3514                            hunk_excerpt_start,
3515                            *end_of_current_insert,
3516                        );
3517
3518                        // For every existing hunk, determine if it was previously expanded
3519                        // and if it should currently be expanded.
3520                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3521                        let should_expand_hunk = match &change_kind {
3522                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3523                                was_previously_expanded || all_diff_hunks_expanded
3524                            }
3525                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3526                                let intersects = hunk_buffer_range.is_empty()
3527                                    || hunk_buffer_range.end > edit_buffer_start;
3528                                if *expand {
3529                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3530                                } else {
3531                                    !intersects
3532                                        && (was_previously_expanded || all_diff_hunks_expanded)
3533                                }
3534                            }
3535                            _ => was_previously_expanded || all_diff_hunks_expanded,
3536                        };
3537
3538                        if should_expand_hunk {
3539                            did_expand_hunks = true;
3540                            log::trace!(
3541                                "expanding hunk {:?}, excerpt:{:?}",
3542                                hunk_excerpt_start..hunk_excerpt_end,
3543                                excerpt.id
3544                            );
3545
3546                            if !hunk.diff_base_byte_range.is_empty()
3547                                && hunk_buffer_range.start >= edit_buffer_start
3548                                && hunk_buffer_range.start <= excerpt_buffer_end
3549                                && snapshot.show_deleted_hunks
3550                            {
3551                                let base_text = diff.base_text();
3552                                let mut text_cursor =
3553                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3554                                let mut base_text_summary = text_cursor
3555                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3556
3557                                let mut has_trailing_newline = false;
3558                                if base_text_summary.last_line_chars > 0 {
3559                                    base_text_summary += TextSummary::newline();
3560                                    has_trailing_newline = true;
3561                                }
3562
3563                                new_diff_transforms.push(
3564                                    DiffTransform::DeletedHunk {
3565                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3566                                        summary: base_text_summary,
3567                                        buffer_id: excerpt.buffer_id,
3568                                        hunk_info,
3569                                        has_trailing_newline,
3570                                    },
3571                                    (),
3572                                );
3573                            }
3574
3575                            if !hunk_buffer_range.is_empty() {
3576                                *end_of_current_insert =
3577                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3578                            }
3579                        }
3580                    }
3581                }
3582            }
3583
3584            if excerpts.end() <= edit.new.end {
3585                excerpts.next();
3586            } else {
3587                break;
3588            }
3589        }
3590
3591        did_expand_hunks || !old_expanded_hunks.is_empty()
3592    }
3593
3594    fn append_diff_transforms(
3595        new_transforms: &mut SumTree<DiffTransform>,
3596        subtree: SumTree<DiffTransform>,
3597    ) {
3598        if let Some(DiffTransform::BufferContent {
3599            inserted_hunk_info,
3600            summary,
3601        }) = subtree.first()
3602            && Self::extend_last_buffer_content_transform(
3603                new_transforms,
3604                *inserted_hunk_info,
3605                *summary,
3606            )
3607        {
3608            let mut cursor = subtree.cursor::<()>(());
3609            cursor.next();
3610            cursor.next();
3611            new_transforms.append(cursor.suffix(), ());
3612            return;
3613        }
3614        new_transforms.append(subtree, ());
3615    }
3616
3617    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3618        if let DiffTransform::BufferContent {
3619            inserted_hunk_info: inserted_hunk_anchor,
3620            summary,
3621        } = transform
3622            && Self::extend_last_buffer_content_transform(
3623                new_transforms,
3624                inserted_hunk_anchor,
3625                summary,
3626            )
3627        {
3628            return;
3629        }
3630        new_transforms.push(transform, ());
3631    }
3632
3633    fn push_buffer_content_transform(
3634        old_snapshot: &MultiBufferSnapshot,
3635        new_transforms: &mut SumTree<DiffTransform>,
3636        end_offset: ExcerptOffset,
3637        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3638    ) {
3639        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3640            (end_offset.min(insertion_end_offset), Some(hunk_info))
3641        });
3642        let unchanged_region = [(end_offset, None)];
3643
3644        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3645        {
3646            let start_offset = new_transforms.summary().excerpt_len();
3647            if end_offset <= start_offset {
3648                continue;
3649            }
3650            let summary_to_add = old_snapshot
3651                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3652
3653            if !Self::extend_last_buffer_content_transform(
3654                new_transforms,
3655                inserted_hunk_info,
3656                summary_to_add,
3657            ) {
3658                new_transforms.push(
3659                    DiffTransform::BufferContent {
3660                        summary: summary_to_add,
3661                        inserted_hunk_info,
3662                    },
3663                    (),
3664                )
3665            }
3666        }
3667    }
3668
3669    fn extend_last_buffer_content_transform(
3670        new_transforms: &mut SumTree<DiffTransform>,
3671        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3672        summary_to_add: MBTextSummary,
3673    ) -> bool {
3674        let mut did_extend = false;
3675        new_transforms.update_last(
3676            |last_transform| {
3677                if let DiffTransform::BufferContent {
3678                    summary,
3679                    inserted_hunk_info: inserted_hunk_anchor,
3680                } = last_transform
3681                    && *inserted_hunk_anchor == new_inserted_hunk_info
3682                {
3683                    *summary += summary_to_add;
3684                    did_extend = true;
3685                }
3686            },
3687            (),
3688        );
3689        did_extend
3690    }
3691
3692    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3693        let snapshot = self.snapshot(cx);
3694        let excerpt_id = range.end.excerpt_id;
3695        let point_range = range.to_point(&snapshot);
3696        let expand = !self.single_hunk_is_expanded(range, cx);
3697        let edits =
3698            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3699        if !edits.is_empty() {
3700            self.subscriptions.publish(edits);
3701        }
3702        cx.emit(Event::DiffHunksToggled);
3703        cx.emit(Event::Edited {
3704            edited_buffer: None,
3705        });
3706    }
3707}
3708
3709fn build_excerpt_ranges(
3710    ranges: impl IntoIterator<Item = Range<Point>>,
3711    context_line_count: u32,
3712    buffer_snapshot: &BufferSnapshot,
3713) -> Vec<ExcerptRange<Point>> {
3714    ranges
3715        .into_iter()
3716        .map(|range| {
3717            let start_row = range.start.row.saturating_sub(context_line_count);
3718            let start = Point::new(start_row, 0);
3719            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3720            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3721            ExcerptRange {
3722                context: start..end,
3723                primary: range,
3724            }
3725        })
3726        .collect()
3727}
3728
3729#[cfg(any(test, feature = "test-support"))]
3730impl MultiBuffer {
3731    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3732        let buffer = cx.new(|cx| Buffer::local(text, cx));
3733        cx.new(|cx| Self::singleton(buffer, cx))
3734    }
3735
3736    pub fn build_multi<const COUNT: usize>(
3737        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3738        cx: &mut gpui::App,
3739    ) -> Entity<Self> {
3740        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3741        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3742            let buffer = cx.new(|cx| Buffer::local(text, cx));
3743            let snapshot = buffer.read(cx).snapshot();
3744            let excerpt_ranges = ranges
3745                .into_iter()
3746                .map(ExcerptRange::new)
3747                .collect::<Vec<_>>();
3748            multi.update(cx, |multi, cx| {
3749                multi.set_excerpt_ranges_for_path(
3750                    PathKey::sorted(ix as u64),
3751                    buffer,
3752                    &snapshot,
3753                    excerpt_ranges,
3754                    cx,
3755                )
3756            });
3757        }
3758
3759        multi
3760    }
3761
3762    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3763        cx.new(|cx| Self::singleton(buffer, cx))
3764    }
3765
3766    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3767        cx.new(|cx| {
3768            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3769            let mutation_count = rng.random_range(1..=5);
3770            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3771            multibuffer
3772        })
3773    }
3774
3775    pub fn randomly_edit(
3776        &mut self,
3777        rng: &mut impl rand::Rng,
3778        edit_count: usize,
3779        cx: &mut Context<Self>,
3780    ) {
3781        use util::RandomCharIter;
3782
3783        let snapshot = self.read(cx);
3784        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3785        let mut last_end = None;
3786        for _ in 0..edit_count {
3787            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3788                break;
3789            }
3790
3791            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3792            let end =
3793                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3794            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3795            last_end = Some(end);
3796
3797            let mut range = start..end;
3798            if rng.random_bool(0.2) {
3799                mem::swap(&mut range.start, &mut range.end);
3800            }
3801
3802            let new_text_len = rng.random_range(0..10);
3803            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3804
3805            edits.push((range, new_text.into()));
3806        }
3807        log::info!("mutating multi-buffer with {:?}", edits);
3808        drop(snapshot);
3809
3810        self.edit(edits, None, cx);
3811    }
3812
3813    pub fn randomly_edit_excerpts(
3814        &mut self,
3815        rng: &mut impl rand::Rng,
3816        mutation_count: usize,
3817        cx: &mut Context<Self>,
3818    ) {
3819        use rand::prelude::*;
3820        use std::env;
3821        use util::RandomCharIter;
3822
3823        let max_excerpts = env::var("MAX_EXCERPTS")
3824            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3825            .unwrap_or(5);
3826
3827        let mut buffers = Vec::new();
3828        for _ in 0..mutation_count {
3829            if rng.random_bool(0.05) {
3830                log::info!("Clearing multi-buffer");
3831                self.clear(cx);
3832                continue;
3833            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3834                let ids = self.excerpt_ids();
3835                let mut excerpts = HashSet::default();
3836                for _ in 0..rng.random_range(0..ids.len()) {
3837                    excerpts.extend(ids.choose(rng).copied());
3838                }
3839
3840                let line_count = rng.random_range(0..5);
3841
3842                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3843
3844                self.expand_excerpts(
3845                    excerpts.iter().cloned(),
3846                    line_count,
3847                    ExpandExcerptDirection::UpAndDown,
3848                    cx,
3849                );
3850                continue;
3851            }
3852
3853            let excerpt_ids = self.excerpt_ids();
3854            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3855                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3856                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3857                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3858                    let buffer = buffers.last().unwrap().read(cx);
3859                    log::info!(
3860                        "Creating new buffer {} with text: {:?}",
3861                        buffer.remote_id(),
3862                        buffer.text()
3863                    );
3864                    buffers.last().unwrap().clone()
3865                } else {
3866                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3867                };
3868
3869                let buffer = buffer_handle.read(cx);
3870                let buffer_text = buffer.text();
3871                let ranges = (0..rng.random_range(0..5))
3872                    .map(|_| {
3873                        let end_ix =
3874                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3875                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3876                        ExcerptRange::new(start_ix..end_ix)
3877                    })
3878                    .collect::<Vec<_>>();
3879                log::info!(
3880                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3881                    buffer_handle.read(cx).remote_id(),
3882                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3883                    ranges
3884                        .iter()
3885                        .map(|r| &buffer_text[r.context.clone()])
3886                        .collect::<Vec<_>>()
3887                );
3888
3889                let excerpt_id =
3890                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3891                log::info!("Inserted with ids: {:?}", excerpt_id);
3892            } else {
3893                let remove_count = rng.random_range(1..=excerpt_ids.len());
3894                let mut excerpts_to_remove = excerpt_ids
3895                    .choose_multiple(rng, remove_count)
3896                    .cloned()
3897                    .collect::<Vec<_>>();
3898                let snapshot = self.snapshot.borrow();
3899                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3900                drop(snapshot);
3901                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3902                self.remove_excerpts(excerpts_to_remove, cx);
3903            }
3904        }
3905    }
3906
3907    pub fn randomly_mutate(
3908        &mut self,
3909        rng: &mut impl rand::Rng,
3910        mutation_count: usize,
3911        cx: &mut Context<Self>,
3912    ) {
3913        use rand::prelude::*;
3914
3915        if rng.random_bool(0.7) || self.singleton {
3916            let buffer = self
3917                .buffers
3918                .values()
3919                .choose(rng)
3920                .map(|state| state.buffer.clone());
3921
3922            if let Some(buffer) = buffer {
3923                buffer.update(cx, |buffer, cx| {
3924                    if rng.random() {
3925                        buffer.randomly_edit(rng, mutation_count, cx);
3926                    } else {
3927                        buffer.randomly_undo_redo(rng, cx);
3928                    }
3929                });
3930            } else {
3931                self.randomly_edit(rng, mutation_count, cx);
3932            }
3933        } else {
3934            self.randomly_edit_excerpts(rng, mutation_count, cx);
3935        }
3936
3937        self.check_invariants(cx);
3938    }
3939
3940    fn check_invariants(&self, cx: &App) {
3941        self.read(cx).check_invariants();
3942    }
3943}
3944
3945impl EventEmitter<Event> for MultiBuffer {}
3946
3947impl MultiBufferSnapshot {
3948    pub fn text(&self) -> String {
3949        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3950            .map(|chunk| chunk.text)
3951            .collect()
3952    }
3953
3954    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3955        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3956            .flat_map(|c| c.chars().rev())
3957    }
3958
3959    fn reversed_chunks_in_range(
3960        &self,
3961        range: Range<MultiBufferOffset>,
3962    ) -> ReversedMultiBufferChunks<'_> {
3963        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3964        cursor.seek(&range.end);
3965        let current_chunks = cursor.region().as_ref().map(|region| {
3966            let start_overshoot = range.start.saturating_sub(region.range.start);
3967            let end_overshoot = range.end - region.range.start;
3968            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3969            let start = region.buffer_range.start + start_overshoot;
3970            region.buffer.reversed_chunks_in_range(start..end)
3971        });
3972        ReversedMultiBufferChunks {
3973            cursor,
3974            current_chunks,
3975            start: range.start,
3976            offset: range.end,
3977        }
3978    }
3979
3980    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3981        let offset = position.to_offset(self);
3982        self.text_for_range(offset..self.len())
3983            .flat_map(|chunk| chunk.chars())
3984    }
3985
3986    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3987        self.chunks(range, false).map(|chunk| chunk.text)
3988    }
3989
3990    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3991        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3992            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3993    }
3994
3995    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3996    where
3997        T: ToOffset,
3998    {
3999        let position = position.to_offset(self);
4000        position == self.clip_offset(position, Bias::Left)
4001            && self
4002                .bytes_in_range(position..self.len())
4003                .flatten()
4004                .copied()
4005                .take(needle.len())
4006                .eq(needle.bytes())
4007    }
4008
4009    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4010        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4011    }
4012
4013    pub fn diff_hunks_in_range<T: ToPoint>(
4014        &self,
4015        range: Range<T>,
4016    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4017        let query_range = range.start.to_point(self)..range.end.to_point(self);
4018        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4019            let diff = self.diffs.get(&buffer.remote_id())?;
4020            let iter = if let Some(main_buffer) = &diff.main_buffer {
4021                let buffer_start = buffer.point_to_offset(buffer_range.start);
4022                let buffer_end = buffer.point_to_offset(buffer_range.end);
4023                itertools::Either::Left(
4024                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4025                        .map(move |hunk| (hunk, buffer, true)),
4026                )
4027            } else {
4028                let buffer_start = buffer.anchor_before(buffer_range.start);
4029                let buffer_end = buffer.anchor_after(buffer_range.end);
4030                itertools::Either::Right(
4031                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4032                        .map(move |hunk| (hunk, buffer, false)),
4033                )
4034            };
4035            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4036                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4037                    return None;
4038                }
4039                let range = if is_inverted {
4040                    hunk.diff_base_byte_range.to_point(&buffer)
4041                } else {
4042                    hunk.range.clone()
4043                };
4044                Some((range, (hunk, is_inverted)))
4045            }))
4046        })
4047        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4048            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4049            {
4050                return None;
4051            }
4052            let end_row = if range.end.column == 0 {
4053                range.end.row
4054            } else {
4055                range.end.row + 1
4056            };
4057
4058            let word_diffs =
4059                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4060                    .then(|| {
4061                        let mut word_diffs = Vec::new();
4062
4063                        if self.show_deleted_hunks || is_inverted {
4064                            let hunk_start_offset = if is_inverted {
4065                                Anchor::in_buffer(
4066                                    excerpt.id,
4067                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4068                                )
4069                                .to_offset(self)
4070                            } else {
4071                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4072                                    .to_offset(self)
4073                            };
4074
4075                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4076                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4077                            }));
4078                        }
4079
4080                        if !is_inverted {
4081                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4082                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4083                            }));
4084                        }
4085                        word_diffs
4086                    })
4087                    .unwrap_or_default();
4088
4089            let buffer_range = if is_inverted {
4090                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4091                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4092            } else {
4093                hunk.buffer_range.clone()
4094            };
4095            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4096                DiffHunkStatusKind::Deleted
4097            } else if hunk.diff_base_byte_range.is_empty() {
4098                DiffHunkStatusKind::Added
4099            } else {
4100                DiffHunkStatusKind::Modified
4101            };
4102            Some(MultiBufferDiffHunk {
4103                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4104                buffer_id: excerpt.buffer_id,
4105                excerpt_id: excerpt.id,
4106                buffer_range,
4107                word_diffs,
4108                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4109                    ..BufferOffset(hunk.diff_base_byte_range.end),
4110                status: DiffHunkStatus {
4111                    kind: status_kind,
4112                    secondary: hunk.secondary_status,
4113                },
4114            })
4115        })
4116    }
4117
4118    fn excerpts_for_range<T: ToOffset>(
4119        &self,
4120        range: Range<T>,
4121    ) -> impl Iterator<Item = &Excerpt> + '_ {
4122        let range = range.start.to_offset(self)..range.end.to_offset(self);
4123        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4124        cursor.seek(&range.start);
4125        std::iter::from_fn(move || {
4126            let region = cursor.region()?;
4127            if region.range.start > range.end
4128                || region.range.start == range.end && region.range.start > range.start
4129            {
4130                return None;
4131            }
4132            let excerpt = region.excerpt;
4133            cursor.next_excerpt_forwards();
4134            Some(excerpt)
4135        })
4136    }
4137
4138    pub fn excerpt_ids_for_range<T: ToOffset>(
4139        &self,
4140        range: Range<T>,
4141    ) -> impl Iterator<Item = ExcerptId> + '_ {
4142        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4143    }
4144
4145    pub fn buffer_ids_for_range<T: ToOffset>(
4146        &self,
4147        range: Range<T>,
4148    ) -> impl Iterator<Item = BufferId> + '_ {
4149        self.excerpts_for_range(range)
4150            .map(|excerpt| excerpt.buffer_id)
4151    }
4152
4153    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4154    ///
4155    /// The passed in anchors must be ordered.
4156    pub fn text_anchors_to_visible_anchors(
4157        &self,
4158        anchors: impl IntoIterator<Item = text::Anchor>,
4159    ) -> Vec<Option<Anchor>> {
4160        let anchors = anchors.into_iter();
4161        let mut result = Vec::with_capacity(anchors.size_hint().0);
4162        let mut anchors = anchors.peekable();
4163        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4164        'anchors: while let Some(anchor) = anchors.peek() {
4165            let Some(buffer_id) = anchor.buffer_id else {
4166                anchors.next();
4167                result.push(None);
4168                continue 'anchors;
4169            };
4170            let mut same_buffer_anchors =
4171                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4172
4173            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4174                let Some(mut next) = same_buffer_anchors.next() else {
4175                    continue 'anchors;
4176                };
4177                'excerpts: for locator in locators.iter() {
4178                    if cursor.seek_forward(&Some(locator), Bias::Left)
4179                        && let Some(excerpt) = cursor.item()
4180                    {
4181                        loop {
4182                            // anchor is before the first excerpt
4183                            if excerpt
4184                                .range
4185                                .context
4186                                .start
4187                                .cmp(&next, &excerpt.buffer)
4188                                .is_gt()
4189                            {
4190                                // so we skip it and try the next anchor
4191                                result.push(None);
4192                                match same_buffer_anchors.next() {
4193                                    Some(anchor) => next = anchor,
4194                                    None => continue 'anchors,
4195                                }
4196                            // anchor is within the excerpt
4197                            } else if excerpt
4198                                .range
4199                                .context
4200                                .end
4201                                .cmp(&next, &excerpt.buffer)
4202                                .is_ge()
4203                            {
4204                                // record it and all following anchors that are within
4205                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4206                                result.extend(
4207                                    same_buffer_anchors
4208                                        .peeking_take_while(|a| {
4209                                            excerpt
4210                                                .range
4211                                                .context
4212                                                .end
4213                                                .cmp(a, &excerpt.buffer)
4214                                                .is_ge()
4215                                        })
4216                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4217                                );
4218                                match same_buffer_anchors.next() {
4219                                    Some(anchor) => next = anchor,
4220                                    None => continue 'anchors,
4221                                }
4222                            // anchor is after the excerpt, try the next one
4223                            } else {
4224                                continue 'excerpts;
4225                            }
4226                        }
4227                    }
4228                }
4229                // account for `next`
4230                result.push(None);
4231            }
4232            result.extend(same_buffer_anchors.map(|_| None));
4233        }
4234
4235        result
4236    }
4237
4238    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4239        &self,
4240        ranges: impl Iterator<Item = Range<T>>,
4241    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4242        ranges.flat_map(|range| {
4243            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4244                .into_iter()
4245        })
4246    }
4247
4248    pub fn range_to_buffer_ranges<R, T>(
4249        &self,
4250        range: R,
4251    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4252    where
4253        R: RangeBounds<T>,
4254        T: ToOffset,
4255    {
4256        self.range_to_buffer_ranges_with_context(range)
4257            .into_iter()
4258            .map(|(buffer, range, id, _context)| (buffer, range, id))
4259            .collect()
4260    }
4261
4262    pub fn range_to_buffer_ranges_with_context<R, T>(
4263        &self,
4264        range: R,
4265    ) -> Vec<(
4266        &BufferSnapshot,
4267        Range<BufferOffset>,
4268        ExcerptId,
4269        Range<text::Anchor>,
4270    )>
4271    where
4272        R: RangeBounds<T>,
4273        T: ToOffset,
4274    {
4275        let start = match range.start_bound() {
4276            Bound::Included(start) => start.to_offset(self),
4277            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4278            Bound::Unbounded => MultiBufferOffset::ZERO,
4279        };
4280        let end_bound = match range.end_bound() {
4281            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4282            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4283            Bound::Unbounded => Bound::Unbounded,
4284        };
4285        let bounds = (Bound::Included(start), end_bound);
4286
4287        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4288        cursor.seek(&start);
4289
4290        let mut result: Vec<(
4291            &BufferSnapshot,
4292            Range<BufferOffset>,
4293            ExcerptId,
4294            Range<text::Anchor>,
4295        )> = Vec::new();
4296        while let Some(region) = cursor.region() {
4297            let dominated_by_end_bound = match end_bound {
4298                Bound::Included(end) => region.range.start > end,
4299                Bound::Excluded(end) => region.range.start >= end,
4300                Bound::Unbounded => false,
4301            };
4302            if dominated_by_end_bound {
4303                break;
4304            }
4305            if region.is_main_buffer {
4306                let start_overshoot = start.saturating_sub(region.range.start);
4307                let end_offset = match end_bound {
4308                    Bound::Included(end) | Bound::Excluded(end) => end,
4309                    Bound::Unbounded => region.range.end,
4310                };
4311                let end_overshoot = end_offset.saturating_sub(region.range.start);
4312                let start = region
4313                    .buffer_range
4314                    .end
4315                    .min(region.buffer_range.start + start_overshoot);
4316                let end = region
4317                    .buffer_range
4318                    .end
4319                    .min(region.buffer_range.start + end_overshoot);
4320                let context = region.excerpt.range.context.clone();
4321                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4322                    *excerpt_id == region.excerpt.id && prev_range.end == start
4323                }) {
4324                    prev.1.end = end;
4325                } else {
4326                    result.push((region.buffer, start..end, region.excerpt.id, context));
4327                }
4328            }
4329            cursor.next();
4330        }
4331
4332        if let Some(excerpt) = cursor.excerpt() {
4333            let dominated_by_prev_excerpt =
4334                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4335            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4336                let excerpt_position = self.len();
4337                if bounds.contains(&excerpt_position) {
4338                    let buffer_offset =
4339                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4340                    let context = excerpt.range.context.clone();
4341                    result.push((
4342                        &excerpt.buffer,
4343                        buffer_offset..buffer_offset,
4344                        excerpt.id,
4345                        context,
4346                    ));
4347                }
4348            }
4349        }
4350
4351        result
4352    }
4353
4354    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4355        &self,
4356        range: Range<T>,
4357    ) -> impl Iterator<
4358        Item = (
4359            &BufferSnapshot,
4360            Range<BufferOffset>,
4361            ExcerptId,
4362            Option<Anchor>,
4363        ),
4364    > + '_ {
4365        let start = range.start.to_offset(self);
4366        let end = range.end.to_offset(self);
4367
4368        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4369        cursor.seek(&start);
4370
4371        std::iter::from_fn(move || {
4372            let region = cursor.region()?;
4373            if region.range.start > end {
4374                return None;
4375            }
4376            let start_overshoot = start.saturating_sub(region.range.start);
4377            let end_overshoot = end.saturating_sub(region.range.start);
4378            let start = region
4379                .buffer_range
4380                .end
4381                .min(region.buffer_range.start + start_overshoot);
4382            let end = region
4383                .buffer_range
4384                .end
4385                .min(region.buffer_range.start + end_overshoot);
4386
4387            let region_excerpt_id = region.excerpt.id;
4388            let deleted_hunk_anchor = if region.is_main_buffer {
4389                None
4390            } else {
4391                Some(self.anchor_before(region.range.start))
4392            };
4393            let result = (
4394                region.buffer,
4395                start..end,
4396                region_excerpt_id,
4397                deleted_hunk_anchor,
4398            );
4399            cursor.next();
4400            Some(result)
4401        })
4402    }
4403
4404    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4405    /// coordinates.
4406    ///
4407    /// The given callback will be called for every excerpt intersecting the given range. It will
4408    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4409    /// The callback should return an iterator of metadata items from that buffer, each paired
4410    /// with a buffer range.
4411    ///
4412    /// The returned iterator yields each of these metadata items, paired with its range in
4413    /// multi-buffer coordinates.
4414    fn lift_buffer_metadata<'a, MBD, M, I>(
4415        &'a self,
4416        query_range: Range<MBD>,
4417        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4418    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4419    where
4420        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4421        MBD: MultiBufferDimension
4422            + Ord
4423            + Sub<Output = MBD::TextDimension>
4424            + ops::Add<MBD::TextDimension, Output = MBD>
4425            + ops::AddAssign<MBD::TextDimension>,
4426        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4427            + ops::Add<Output = MBD::TextDimension>
4428            + AddAssign<MBD::TextDimension>
4429            + Ord,
4430    {
4431        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4432        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4433
4434        // Find the excerpt and buffer offset where the given range ends.
4435        cursor.seek(&query_range.end);
4436        let mut range_end = None;
4437        while let Some(region) = cursor.region() {
4438            if region.is_main_buffer {
4439                let mut buffer_end = region.buffer_range.start;
4440                let overshoot = if query_range.end > region.range.start {
4441                    query_range.end - region.range.start
4442                } else {
4443                    <MBD::TextDimension>::default()
4444                };
4445                buffer_end = buffer_end + overshoot;
4446                range_end = Some((region.excerpt.id, buffer_end));
4447                break;
4448            }
4449            cursor.next();
4450        }
4451
4452        cursor.seek(&query_range.start);
4453
4454        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4455            && region.range.start > MBD::default()
4456        {
4457            cursor.prev()
4458        } else if let Some(region) = cursor.region()
4459            && region.is_main_buffer
4460            && region.diff_hunk_status.is_some()
4461        {
4462            cursor.prev();
4463            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4464                cursor.next();
4465            }
4466        }
4467
4468        iter::from_fn(move || {
4469            loop {
4470                let excerpt = cursor.excerpt()?;
4471
4472                // If we have already retrieved metadata for this excerpt, continue to use it.
4473                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4474                    .as_mut()
4475                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4476                {
4477                    Some(metadata)
4478                }
4479                // Otherwise, compute the intersection of the input range with the excerpt's range,
4480                // and retrieve the metadata for the resulting range.
4481                else {
4482                    let region = cursor.region()?;
4483                    let mut buffer_start;
4484                    if region.is_main_buffer {
4485                        buffer_start = region.buffer_range.start;
4486                        if query_range.start > region.range.start {
4487                            let overshoot = query_range.start - region.range.start;
4488                            buffer_start = buffer_start + overshoot;
4489                        }
4490                        buffer_start = buffer_start.min(region.buffer_range.end);
4491                    } else {
4492                        buffer_start = cursor.main_buffer_position()?;
4493                    };
4494                    let mut buffer_end = excerpt
4495                        .range
4496                        .context
4497                        .end
4498                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4499                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4500                        && excerpt.id == end_excerpt_id
4501                    {
4502                        buffer_end = buffer_end.min(end_buffer_offset);
4503                    }
4504
4505                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4506                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4507                    })
4508                };
4509
4510                // Visit each metadata item.
4511                if let Some((metadata_buffer_range, metadata)) =
4512                    metadata_iter.and_then(Iterator::next)
4513                {
4514                    // Find the multibuffer regions that contain the start and end of
4515                    // the metadata item's range.
4516                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4517                        while let Some(region) = cursor.region() {
4518                            if (region.is_main_buffer
4519                                && (region.buffer_range.end >= metadata_buffer_range.start
4520                                    || cursor.is_at_end_of_excerpt()))
4521                                || (!region.is_main_buffer
4522                                    && region.buffer_range.start == metadata_buffer_range.start)
4523                            {
4524                                break;
4525                            }
4526                            cursor.next();
4527                        }
4528                    }
4529                    let start_region = cursor.region()?.clone();
4530                    while let Some(region) = cursor.region() {
4531                        if region.is_main_buffer
4532                            && (region.buffer_range.end > metadata_buffer_range.end
4533                                || cursor.is_at_end_of_excerpt())
4534                        {
4535                            break;
4536                        }
4537                        cursor.next();
4538                    }
4539                    let end_region = cursor.region();
4540
4541                    // Convert the metadata item's range into multibuffer coordinates.
4542                    let mut start_position = start_region.range.start;
4543                    let region_buffer_start = start_region.buffer_range.start;
4544                    if start_region.is_main_buffer
4545                        && metadata_buffer_range.start > region_buffer_start
4546                    {
4547                        start_position =
4548                            start_position + (metadata_buffer_range.start - region_buffer_start);
4549                        start_position = start_position.min(start_region.range.end);
4550                    }
4551
4552                    let mut end_position = self.max_position();
4553                    if let Some(end_region) = &end_region {
4554                        end_position = end_region.range.start;
4555                        debug_assert!(end_region.is_main_buffer);
4556                        let region_buffer_start = end_region.buffer_range.start;
4557                        if metadata_buffer_range.end > region_buffer_start {
4558                            end_position =
4559                                end_position + (metadata_buffer_range.end - region_buffer_start);
4560                        }
4561                        end_position = end_position.min(end_region.range.end);
4562                    }
4563
4564                    if start_position <= query_range.end && end_position >= query_range.start {
4565                        return Some((start_position..end_position, metadata, excerpt));
4566                    }
4567                }
4568                // When there are no more metadata items for this excerpt, move to the next excerpt.
4569                else {
4570                    current_excerpt_metadata.take();
4571                    if let Some((end_excerpt_id, _)) = range_end
4572                        && excerpt.id == end_excerpt_id
4573                    {
4574                        return None;
4575                    }
4576                    cursor.next_excerpt_forwards();
4577                }
4578            }
4579        })
4580    }
4581
4582    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4583        let offset = position.to_offset(self);
4584
4585        let mut cursor = self
4586            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4587            );
4588        cursor.seek(&DimensionPair {
4589            key: offset,
4590            value: None,
4591        });
4592        cursor.seek_to_start_of_current_excerpt();
4593        let excerpt = cursor.excerpt()?;
4594
4595        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4596        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4597        let current_position = self
4598            .anchor_before(offset)
4599            .text_anchor
4600            .to_offset(&excerpt.buffer);
4601
4602        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4603            if let Some(main_buffer) = &diff.main_buffer {
4604                for hunk in diff
4605                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4606                {
4607                    if hunk.diff_base_byte_range.end >= current_position {
4608                        continue;
4609                    }
4610                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4611                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4612                    return Some(MultiBufferRow(start.row));
4613                }
4614            } else {
4615                let excerpt_end = excerpt
4616                    .buffer
4617                    .anchor_before(excerpt_end.min(current_position));
4618                for hunk in diff.hunks_intersecting_range_rev(
4619                    excerpt.range.context.start..excerpt_end,
4620                    &excerpt.buffer,
4621                ) {
4622                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4623                    if hunk_end >= current_position {
4624                        continue;
4625                    }
4626                    let start =
4627                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4628                    return Some(MultiBufferRow(start.row));
4629                }
4630            }
4631        }
4632
4633        loop {
4634            cursor.prev_excerpt();
4635            let excerpt = cursor.excerpt()?;
4636
4637            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4638                continue;
4639            };
4640            if let Some(main_buffer) = &diff.main_buffer {
4641                let Some(hunk) = diff
4642                    .hunks_intersecting_base_text_range_rev(
4643                        excerpt.range.context.to_offset(&excerpt.buffer),
4644                        main_buffer,
4645                    )
4646                    .next()
4647                else {
4648                    continue;
4649                };
4650                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4651                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4652                return Some(MultiBufferRow(start.row));
4653            } else {
4654                let Some(hunk) = diff
4655                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4656                    .next()
4657                else {
4658                    continue;
4659                };
4660                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4661                return Some(MultiBufferRow(start.row));
4662            }
4663        }
4664    }
4665
4666    pub fn has_diff_hunks(&self) -> bool {
4667        self.diffs.values().any(|diff| !diff.is_empty())
4668    }
4669
4670    pub fn is_inside_word<T: ToOffset>(
4671        &self,
4672        position: T,
4673        scope_context: Option<CharScopeContext>,
4674    ) -> bool {
4675        let position = position.to_offset(self);
4676        let classifier = self
4677            .char_classifier_at(position)
4678            .scope_context(scope_context);
4679        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4680        let prev_char_kind = self
4681            .reversed_chars_at(position)
4682            .next()
4683            .map(|c| classifier.kind(c));
4684        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4685    }
4686
4687    pub fn surrounding_word<T: ToOffset>(
4688        &self,
4689        start: T,
4690        scope_context: Option<CharScopeContext>,
4691    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4692        let mut start = start.to_offset(self);
4693        let mut end = start;
4694        let mut next_chars = self.chars_at(start).peekable();
4695        let mut prev_chars = self.reversed_chars_at(start).peekable();
4696
4697        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4698
4699        let word_kind = cmp::max(
4700            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4701            next_chars.peek().copied().map(|c| classifier.kind(c)),
4702        );
4703
4704        for ch in prev_chars {
4705            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4706                start -= ch.len_utf8();
4707            } else {
4708                break;
4709            }
4710        }
4711
4712        for ch in next_chars {
4713            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4714                end += ch.len_utf8();
4715            } else {
4716                break;
4717            }
4718        }
4719
4720        (start..end, word_kind)
4721    }
4722
4723    pub fn char_kind_before<T: ToOffset>(
4724        &self,
4725        start: T,
4726        scope_context: Option<CharScopeContext>,
4727    ) -> Option<CharKind> {
4728        let start = start.to_offset(self);
4729        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4730        self.reversed_chars_at(start)
4731            .next()
4732            .map(|ch| classifier.kind(ch))
4733    }
4734
4735    pub fn is_singleton(&self) -> bool {
4736        self.singleton
4737    }
4738
4739    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4740        if self.singleton {
4741            self.excerpts
4742                .iter()
4743                .next()
4744                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4745        } else {
4746            None
4747        }
4748    }
4749
4750    pub fn len(&self) -> MultiBufferOffset {
4751        self.diff_transforms.summary().output.len
4752    }
4753
4754    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4755        MBD::from_summary(&self.text_summary())
4756    }
4757
4758    pub fn is_empty(&self) -> bool {
4759        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4760    }
4761
4762    pub fn widest_line_number(&self) -> u32 {
4763        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4764        self.excerpts.summary().widest_line_number + 1
4765    }
4766
4767    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4768        let range = range.start.to_offset(self)..range.end.to_offset(self);
4769        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4770        excerpts.seek(&range.start);
4771
4772        let mut chunk;
4773        let mut has_trailing_newline;
4774        let excerpt_bytes;
4775        if let Some(region) = excerpts.region() {
4776            let mut bytes = region.buffer.bytes_in_range(
4777                region.buffer_range.start + (range.start - region.range.start)
4778                    ..(region.buffer_range.start + (range.end - region.range.start))
4779                        .min(region.buffer_range.end),
4780            );
4781            chunk = bytes.next().unwrap_or(&[][..]);
4782            excerpt_bytes = Some(bytes);
4783            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4784            if chunk.is_empty() && has_trailing_newline {
4785                chunk = b"\n";
4786                has_trailing_newline = false;
4787            }
4788        } else {
4789            chunk = &[][..];
4790            excerpt_bytes = None;
4791            has_trailing_newline = false;
4792        };
4793
4794        MultiBufferBytes {
4795            range,
4796            cursor: excerpts,
4797            excerpt_bytes,
4798            has_trailing_newline,
4799            chunk,
4800        }
4801    }
4802
4803    pub fn reversed_bytes_in_range<T: ToOffset>(
4804        &self,
4805        range: Range<T>,
4806    ) -> ReversedMultiBufferBytes<'_> {
4807        let range = range.start.to_offset(self)..range.end.to_offset(self);
4808        let mut chunks = self.reversed_chunks_in_range(range.clone());
4809        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4810        ReversedMultiBufferBytes {
4811            range,
4812            chunks,
4813            chunk,
4814        }
4815    }
4816
4817    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4818        let mut cursor = self.cursor::<Point, Point>();
4819        cursor.seek(&Point::new(start_row.0, 0));
4820        let mut result = MultiBufferRows {
4821            point: Point::new(0, 0),
4822            is_empty: self.excerpts.is_empty(),
4823            is_singleton: self.is_singleton(),
4824            cursor,
4825        };
4826        result.seek(start_row);
4827        result
4828    }
4829
4830    pub fn chunks<T: ToOffset>(
4831        &self,
4832        range: Range<T>,
4833        language_aware: bool,
4834    ) -> MultiBufferChunks<'_> {
4835        let mut chunks = MultiBufferChunks {
4836            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4837                ..ExcerptDimension(MultiBufferOffset::ZERO),
4838            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4839            excerpts: self.excerpts.cursor(()),
4840            diff_transforms: self.diff_transforms.cursor(()),
4841            diffs: &self.diffs,
4842            diff_base_chunks: None,
4843            excerpt_chunks: None,
4844            buffer_chunk: None,
4845            language_aware,
4846        };
4847        let range = range.start.to_offset(self)..range.end.to_offset(self);
4848        chunks.seek(range);
4849        chunks
4850    }
4851
4852    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4853        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4854    }
4855
4856    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4857        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4858    }
4859
4860    pub fn clip_offset_utf16(
4861        &self,
4862        offset: MultiBufferOffsetUtf16,
4863        bias: Bias,
4864    ) -> MultiBufferOffsetUtf16 {
4865        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4866    }
4867
4868    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4869        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4870            buffer.clip_point_utf16(Unclipped(point), bias)
4871        })
4872    }
4873
4874    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4875        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4876    }
4877
4878    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4879        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4880    }
4881
4882    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4883        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4884    }
4885
4886    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4887        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4888    }
4889
4890    #[instrument(skip_all)]
4891    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4892        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4893    }
4894
4895    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4896        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4897    }
4898
4899    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4900        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4901    }
4902
4903    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4904        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4905    }
4906
4907    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4908        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4909    }
4910
4911    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4912        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4913    }
4914
4915    fn clip_dimension<MBD, BD>(
4916        &self,
4917        position: MBD,
4918        bias: Bias,
4919        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4920    ) -> MBD
4921    where
4922        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4923        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4924    {
4925        let mut cursor = self.cursor::<MBD, BD>();
4926        cursor.seek(&position);
4927        if let Some(region) = cursor.region() {
4928            if position >= region.range.end {
4929                return region.range.end;
4930            }
4931            let overshoot = position - region.range.start;
4932            let mut buffer_position = region.buffer_range.start;
4933            buffer_position += overshoot;
4934            let clipped_buffer_position =
4935                clip_buffer_position(region.buffer, buffer_position, bias);
4936            let mut position = region.range.start;
4937            position += clipped_buffer_position - region.buffer_range.start;
4938            position
4939        } else {
4940            self.max_position()
4941        }
4942    }
4943
4944    #[instrument(skip_all)]
4945    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4946        &self,
4947        key: MBR1,
4948        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4949    ) -> MBR2
4950    where
4951        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4952        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4953        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4954        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4955    {
4956        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4957        cursor.seek(&DimensionPair { key, value: None });
4958        if let Some(region) = cursor.region() {
4959            if key >= region.range.end.key {
4960                return region.range.end.value.unwrap();
4961            }
4962            let start_key = region.range.start.key;
4963            let start_value = region.range.start.value.unwrap();
4964            let buffer_start_key = region.buffer_range.start.key;
4965            let buffer_start_value = region.buffer_range.start.value.unwrap();
4966            let mut buffer_key = buffer_start_key;
4967            buffer_key += key - start_key;
4968            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4969            let mut result = start_value;
4970            result += buffer_value - buffer_start_value;
4971            result
4972        } else {
4973            self.max_position()
4974        }
4975    }
4976
4977    pub fn point_to_buffer_offset<T: ToOffset>(
4978        &self,
4979        point: T,
4980    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4981        let offset = point.to_offset(self);
4982        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4983        cursor.seek(&offset);
4984        let region = cursor.region()?;
4985        let overshoot = offset - region.range.start;
4986        let buffer_offset = region.buffer_range.start + overshoot;
4987        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4988            && region.has_trailing_newline
4989            && !region.is_main_buffer
4990        {
4991            let main_buffer_position = cursor.main_buffer_position()?;
4992            let buffer_snapshot = &cursor.excerpt()?.buffer;
4993            return Some((buffer_snapshot, main_buffer_position));
4994        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4995            return None;
4996        }
4997        Some((region.buffer, buffer_offset))
4998    }
4999
5000    pub fn point_to_buffer_point(
5001        &self,
5002        point: Point,
5003    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5004        let mut cursor = self.cursor::<Point, Point>();
5005        cursor.seek(&point);
5006        let region = cursor.region()?;
5007        let overshoot = point - region.range.start;
5008        let buffer_point = region.buffer_range.start + overshoot;
5009        let excerpt = cursor.excerpt()?;
5010        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5011            && region.has_trailing_newline
5012            && !region.is_main_buffer
5013        {
5014            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5015        } else if buffer_point > region.buffer.max_point() {
5016            return None;
5017        }
5018        Some((region.buffer, buffer_point, excerpt.id))
5019    }
5020
5021    pub fn suggested_indents(
5022        &self,
5023        rows: impl IntoIterator<Item = u32>,
5024        cx: &App,
5025    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5026        let mut result = BTreeMap::new();
5027        self.suggested_indents_callback(
5028            rows,
5029            &mut |row, indent| {
5030                result.insert(row, indent);
5031                ControlFlow::Continue(())
5032            },
5033            cx,
5034        );
5035        result
5036    }
5037
5038    // move this to be a generator once those are a thing
5039    pub fn suggested_indents_callback(
5040        &self,
5041        rows: impl IntoIterator<Item = u32>,
5042        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5043        cx: &App,
5044    ) {
5045        let mut rows_for_excerpt = Vec::new();
5046        let mut cursor = self.cursor::<Point, Point>();
5047        let mut rows = rows.into_iter().peekable();
5048        let mut prev_row = u32::MAX;
5049        let mut prev_language_indent_size = IndentSize::default();
5050
5051        while let Some(row) = rows.next() {
5052            cursor.seek(&Point::new(row, 0));
5053            let Some(region) = cursor.region() else {
5054                continue;
5055            };
5056
5057            // Retrieve the language and indent size once for each disjoint region being indented.
5058            let single_indent_size = if row.saturating_sub(1) == prev_row {
5059                prev_language_indent_size
5060            } else {
5061                region
5062                    .buffer
5063                    .language_indent_size_at(Point::new(row, 0), cx)
5064            };
5065            prev_language_indent_size = single_indent_size;
5066            prev_row = row;
5067
5068            let start_buffer_row = region.buffer_range.start.row;
5069            let start_multibuffer_row = region.range.start.row;
5070            let end_multibuffer_row = region.range.end.row;
5071
5072            rows_for_excerpt.push(row);
5073            while let Some(next_row) = rows.peek().copied() {
5074                if end_multibuffer_row > next_row {
5075                    rows_for_excerpt.push(next_row);
5076                    rows.next();
5077                } else {
5078                    break;
5079                }
5080            }
5081
5082            let buffer_rows = rows_for_excerpt
5083                .drain(..)
5084                .map(|row| start_buffer_row + row - start_multibuffer_row);
5085            let buffer_indents = region
5086                .buffer
5087                .suggested_indents(buffer_rows, single_indent_size);
5088            for (row, indent) in buffer_indents {
5089                if cb(
5090                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5091                    indent,
5092                )
5093                .is_break()
5094                {
5095                    return;
5096                }
5097            }
5098        }
5099    }
5100
5101    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5102        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5103            let mut size = buffer.indent_size_for_line(range.start.row);
5104            size.len = size
5105                .len
5106                .min(range.end.column)
5107                .saturating_sub(range.start.column);
5108            size
5109        } else {
5110            IndentSize::spaces(0)
5111        }
5112    }
5113
5114    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5115        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5116            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5117        } else {
5118            LineIndent::spaces(0)
5119        }
5120    }
5121
5122    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5123        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5124
5125        if self.language_settings(cx).extend_comment_on_newline
5126            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5127        {
5128            let delimiters = language_scope.line_comment_prefixes();
5129            for delimiter in delimiters {
5130                if *self
5131                    .chars_at(Point::new(row.0, indent.len() as u32))
5132                    .take(delimiter.chars().count())
5133                    .collect::<String>()
5134                    .as_str()
5135                    == **delimiter
5136                {
5137                    indent.push_str(delimiter);
5138                    break;
5139                }
5140            }
5141        }
5142
5143        indent
5144    }
5145
5146    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5147    where
5148        T: ToOffset,
5149    {
5150        for char in self.reversed_chars_at(position) {
5151            if !char.is_whitespace() {
5152                return false;
5153            }
5154            if char == '\n' {
5155                return true;
5156            }
5157        }
5158        true
5159    }
5160
5161    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5162        while row.0 > 0 {
5163            row.0 -= 1;
5164            if !self.is_line_blank(row) {
5165                return Some(row);
5166            }
5167        }
5168        None
5169    }
5170
5171    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5172        if let Some((_, range)) = self.buffer_line_for_row(row) {
5173            range.end.column - range.start.column
5174        } else {
5175            0
5176        }
5177    }
5178
5179    pub fn buffer_line_for_row(
5180        &self,
5181        row: MultiBufferRow,
5182    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5183        let mut cursor = self.cursor::<Point, Point>();
5184        let point = Point::new(row.0, 0);
5185        cursor.seek(&point);
5186        let region = cursor.region()?;
5187        let overshoot = point.min(region.range.end) - region.range.start;
5188        let buffer_point = region.buffer_range.start + overshoot;
5189        if buffer_point.row > region.buffer_range.end.row {
5190            return None;
5191        }
5192        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5193        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5194            .min(region.buffer_range.end);
5195        Some((region.buffer, line_start..line_end))
5196    }
5197
5198    pub fn max_point(&self) -> Point {
5199        self.text_summary().lines
5200    }
5201
5202    pub fn max_row(&self) -> MultiBufferRow {
5203        MultiBufferRow(self.text_summary().lines.row)
5204    }
5205
5206    pub fn text_summary(&self) -> MBTextSummary {
5207        self.diff_transforms.summary().output
5208    }
5209
5210    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5211    where
5212        MBD: MultiBufferDimension + AddAssign,
5213        O: ToOffset,
5214    {
5215        let range = range.start.to_offset(self)..range.end.to_offset(self);
5216        let mut cursor = self
5217            .diff_transforms
5218            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5219        cursor.seek(&range.start, Bias::Right);
5220
5221        let Some(first_transform) = cursor.item() else {
5222            return MBD::from_summary(&MBTextSummary::default());
5223        };
5224
5225        let diff_transform_start = cursor.start().0;
5226        let diff_transform_end = cursor.end().0;
5227        let diff_start = range.start;
5228        let start_overshoot = diff_start - diff_transform_start;
5229        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5230
5231        let mut result = match first_transform {
5232            DiffTransform::BufferContent { .. } => {
5233                let excerpt_start = cursor.start().1 + start_overshoot;
5234                let excerpt_end = cursor.start().1 + end_overshoot;
5235                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5236            }
5237            DiffTransform::DeletedHunk {
5238                buffer_id,
5239                base_text_byte_range,
5240                has_trailing_newline,
5241                ..
5242            } => {
5243                let buffer_start = base_text_byte_range.start + start_overshoot;
5244                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5245                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5246                    panic!("{:?} is in non-existent deleted hunk", range.start)
5247                };
5248
5249                let include_trailing_newline =
5250                    *has_trailing_newline && range.end >= diff_transform_end;
5251                if include_trailing_newline {
5252                    buffer_end -= 1;
5253                }
5254
5255                let mut summary = base_text
5256                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5257
5258                if include_trailing_newline {
5259                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5260                        &TextSummary::newline(),
5261                    ))
5262                }
5263
5264                let mut result = MBD::default();
5265                result.add_text_dim(&summary);
5266                result
5267            }
5268        };
5269        if range.end < diff_transform_end {
5270            return result;
5271        }
5272
5273        cursor.next();
5274        result.add_mb_text_summary(
5275            &cursor
5276                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5277                .0,
5278        );
5279
5280        let Some(last_transform) = cursor.item() else {
5281            return result;
5282        };
5283
5284        let overshoot = range.end - cursor.start().0;
5285        let suffix = match last_transform {
5286            DiffTransform::BufferContent { .. } => {
5287                let end = cursor.start().1 + overshoot;
5288                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5289            }
5290            DiffTransform::DeletedHunk {
5291                base_text_byte_range,
5292                buffer_id,
5293                has_trailing_newline,
5294                ..
5295            } => {
5296                let buffer_end = base_text_byte_range.start + overshoot;
5297                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5298                    panic!("{:?} is in non-existent deleted hunk", range.end)
5299                };
5300
5301                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5302                    base_text_byte_range.start..buffer_end,
5303                );
5304                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5305                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5306                        &TextSummary::from("\n"),
5307                    ))
5308                }
5309
5310                let mut result = MBD::default();
5311                result.add_text_dim(&suffix);
5312                result
5313            }
5314        };
5315
5316        result += suffix;
5317        result
5318    }
5319
5320    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5321    where
5322        MBD: MultiBufferDimension + AddAssign,
5323    {
5324        let mut summary = MBD::default();
5325        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5326        cursor.seek(&range.start, Bias::Right);
5327        if let Some(excerpt) = cursor.item() {
5328            let mut end_before_newline = cursor.end();
5329            if excerpt.has_trailing_newline {
5330                end_before_newline -= 1;
5331            }
5332
5333            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5334            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5335            let end_in_excerpt =
5336                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5337            summary.add_text_dim(
5338                &excerpt
5339                    .buffer
5340                    .text_summary_for_range::<MBD::TextDimension, _>(
5341                        start_in_excerpt..end_in_excerpt,
5342                    ),
5343            );
5344
5345            if range.end > end_before_newline {
5346                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5347            }
5348
5349            cursor.next();
5350        }
5351
5352        if range.end > *cursor.start() {
5353            summary += cursor
5354                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5355                .0;
5356            if let Some(excerpt) = cursor.item() {
5357                range.end = cmp::max(*cursor.start(), range.end);
5358
5359                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5360                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5361                summary.add_text_dim(
5362                    &excerpt
5363                        .buffer
5364                        .text_summary_for_range::<MBD::TextDimension, _>(
5365                            excerpt_start..end_in_excerpt,
5366                        ),
5367                );
5368            }
5369        }
5370
5371        summary
5372    }
5373
5374    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5375    where
5376        MBD: MultiBufferDimension
5377            + Ord
5378            + Sub<Output = MBD::TextDimension>
5379            + Sub<MBD::TextDimension, Output = MBD>
5380            + AddAssign<MBD::TextDimension>
5381            + Add<MBD::TextDimension, Output = MBD>,
5382        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5383    {
5384        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5385        let locator = self.excerpt_locator_for_id(excerpt_id);
5386        let (start, _, mut item) = self
5387            .excerpts
5388            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5389        let mut start = MBD::from_summary(&start.text);
5390        if item.is_none() && excerpt_id == ExcerptId::max() {
5391            item = self.excerpts.last();
5392            if let Some(last_summary) = self.excerpts.last_summary() {
5393                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5394            }
5395        }
5396
5397        let excerpt_start_position = ExcerptDimension(start);
5398        if self.diff_transforms.is_empty() {
5399            if let Some(excerpt) = item {
5400                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5401                    return excerpt_start_position.0;
5402                }
5403                let excerpt_buffer_start = excerpt
5404                    .range
5405                    .context
5406                    .start
5407                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5408                let excerpt_buffer_end = excerpt
5409                    .range
5410                    .context
5411                    .end
5412                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5413                let buffer_summary = anchor
5414                    .text_anchor
5415                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5416                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5417                let mut position = excerpt_start_position;
5418                if summary > excerpt_buffer_start {
5419                    position += summary - excerpt_buffer_start;
5420                }
5421
5422                position.0
5423            } else {
5424                excerpt_start_position.0
5425            }
5426        } else {
5427            let mut diff_transforms_cursor = self
5428                .diff_transforms
5429                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5430            diff_transforms_cursor.next();
5431
5432            if let Some(excerpt) = item {
5433                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5434                    return self.resolve_summary_for_min_or_max_anchor(
5435                        &Anchor::min(),
5436                        excerpt_start_position,
5437                        &mut diff_transforms_cursor,
5438                    );
5439                }
5440                let excerpt_buffer_start = excerpt
5441                    .range
5442                    .context
5443                    .start
5444                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5445                let excerpt_buffer_end = excerpt
5446                    .range
5447                    .context
5448                    .end
5449                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5450                let buffer_summary = anchor
5451                    .text_anchor
5452                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5453                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5454                let mut position = excerpt_start_position;
5455                if summary > excerpt_buffer_start {
5456                    position += summary - excerpt_buffer_start;
5457                }
5458
5459                if diff_transforms_cursor.start().0 < position {
5460                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5461                }
5462                self.resolve_summary_for_anchor(
5463                    &anchor,
5464                    position,
5465                    &mut diff_transforms_cursor,
5466                    &excerpt.buffer,
5467                )
5468            } else {
5469                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5470                self.resolve_summary_for_min_or_max_anchor(
5471                    &Anchor::max(),
5472                    excerpt_start_position,
5473                    &mut diff_transforms_cursor,
5474                )
5475            }
5476        }
5477    }
5478
5479    /// Maps an anchor's excerpt-space position to its output-space position by
5480    /// walking the diff transforms. The cursor is shared across consecutive
5481    /// calls, so it may already be partway through the transform list.
5482    fn resolve_summary_for_anchor<MBD>(
5483        &self,
5484        anchor: &Anchor,
5485        excerpt_position: ExcerptDimension<MBD>,
5486        diff_transforms: &mut Cursor<
5487            DiffTransform,
5488            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5489        >,
5490        excerpt_buffer: &text::BufferSnapshot,
5491    ) -> MBD
5492    where
5493        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5494    {
5495        loop {
5496            let transform_end_position = diff_transforms.end().0;
5497            let item = diff_transforms.item();
5498            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5499
5500            // A right-biased anchor at a transform boundary belongs to the
5501            // *next* transform, so advance past the current one.
5502            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5503                diff_transforms.next();
5504                continue;
5505            }
5506
5507            let mut position = diff_transforms.start().1;
5508            match item {
5509                Some(DiffTransform::DeletedHunk {
5510                    buffer_id,
5511                    base_text_byte_range,
5512                    hunk_info,
5513                    ..
5514                }) => {
5515                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5516                        && let Some(base_text) =
5517                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5518                        && diff_base_anchor.is_valid(&base_text)
5519                    {
5520                        // The anchor carries a diff-base position — resolve it
5521                        // to a location inside the deleted hunk.
5522                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5523                        if base_text_offset >= base_text_byte_range.start
5524                            && base_text_offset <= base_text_byte_range.end
5525                        {
5526                            let position_in_hunk = base_text
5527                                .text_summary_for_range::<MBD::TextDimension, _>(
5528                                    base_text_byte_range.start..base_text_offset,
5529                                );
5530                            position.0.add_text_dim(&position_in_hunk);
5531                        } else if at_transform_end {
5532                            // diff_base offset falls outside this hunk's range;
5533                            // advance to see if the next transform is a better fit.
5534                            diff_transforms.next();
5535                            continue;
5536                        }
5537                    } else if at_transform_end
5538                        && anchor
5539                            .text_anchor
5540                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5541                            .is_gt()
5542                    {
5543                        // The anchor has no (valid) diff-base position, so it
5544                        // belongs in the buffer content, not in the deleted
5545                        // hunk. However, after an edit deletes the text between
5546                        // the hunk boundary and this anchor, both resolve to
5547                        // the same excerpt_position—landing us here on the
5548                        // DeletedHunk left behind by the shared cursor. Use the
5549                        // CRDT ordering to detect that the anchor is strictly
5550                        // *past* the hunk boundary and skip to the following
5551                        // BufferContent.
5552                        diff_transforms.next();
5553                        continue;
5554                    }
5555                }
5556                _ => {
5557                    // On a BufferContent (or no transform). If the anchor
5558                    // carries a diff_base_anchor it needs a DeletedHunk, so
5559                    // advance to find one.
5560                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5561                        diff_transforms.next();
5562                        continue;
5563                    }
5564                    let overshoot = excerpt_position - diff_transforms.start().0;
5565                    position += overshoot;
5566                }
5567            }
5568
5569            return position.0;
5570        }
5571    }
5572
5573    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5574    fn resolve_summary_for_min_or_max_anchor<MBD>(
5575        &self,
5576        anchor: &Anchor,
5577        excerpt_position: ExcerptDimension<MBD>,
5578        diff_transforms: &mut Cursor<
5579            DiffTransform,
5580            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5581        >,
5582    ) -> MBD
5583    where
5584        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5585    {
5586        loop {
5587            let transform_end_position = diff_transforms.end().0;
5588            let item = diff_transforms.item();
5589            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5590
5591            // A right-biased anchor at a transform boundary belongs to the
5592            // *next* transform, so advance past the current one.
5593            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5594                diff_transforms.next();
5595                continue;
5596            }
5597
5598            let mut position = diff_transforms.start().1;
5599            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5600                let overshoot = excerpt_position - diff_transforms.start().0;
5601                position += overshoot;
5602            }
5603
5604            return position.0;
5605        }
5606    }
5607
5608    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5609        let mut cursor = self
5610            .excerpts
5611            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5612        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5613
5614        cursor.seek(&Some(locator), Bias::Left);
5615        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5616            cursor.prev();
5617        }
5618
5619        let mut position = cursor.start().1;
5620        if let Some(excerpt) = cursor.item()
5621            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5622        {
5623            let excerpt_buffer_start = excerpt
5624                .buffer
5625                .offset_for_anchor(&excerpt.range.context.start);
5626            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5627            let buffer_position = cmp::min(
5628                excerpt_buffer_end,
5629                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5630            );
5631            if buffer_position > excerpt_buffer_start {
5632                position += buffer_position - excerpt_buffer_start;
5633            }
5634        }
5635        position
5636    }
5637
5638    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5639        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5640            excerpt_id = *replacement;
5641        }
5642        excerpt_id
5643    }
5644
5645    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5646    where
5647        MBD: MultiBufferDimension
5648            + Ord
5649            + Sub<Output = MBD::TextDimension>
5650            + AddAssign<MBD::TextDimension>,
5651        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5652        I: 'a + IntoIterator<Item = &'a Anchor>,
5653    {
5654        let mut anchors = anchors.into_iter().peekable();
5655        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5656        let mut diff_transforms_cursor = self
5657            .diff_transforms
5658            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5659        diff_transforms_cursor.next();
5660
5661        let mut summaries = Vec::new();
5662        while let Some(anchor) = anchors.peek() {
5663            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5664
5665            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5666                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5667            });
5668
5669            let locator = self.excerpt_locator_for_id(excerpt_id);
5670            cursor.seek_forward(locator, Bias::Left);
5671            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5672                cursor.prev();
5673            }
5674
5675            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5676            if let Some(excerpt) = cursor.item() {
5677                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5678                    let position = self.resolve_summary_for_min_or_max_anchor(
5679                        &Anchor::min(),
5680                        excerpt_start_position,
5681                        &mut diff_transforms_cursor,
5682                    );
5683                    summaries.extend(excerpt_anchors.map(|_| position));
5684                    continue;
5685                }
5686                let excerpt_buffer_start = excerpt
5687                    .range
5688                    .context
5689                    .start
5690                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5691                let excerpt_buffer_end = excerpt
5692                    .range
5693                    .context
5694                    .end
5695                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5696                for (buffer_summary, anchor) in excerpt
5697                    .buffer
5698                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5699                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5700                    )
5701                {
5702                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5703                    let mut position = excerpt_start_position;
5704                    if summary > excerpt_buffer_start {
5705                        position += summary - excerpt_buffer_start;
5706                    }
5707
5708                    if diff_transforms_cursor.start().0 < position {
5709                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5710                    }
5711
5712                    summaries.push(self.resolve_summary_for_anchor(
5713                        anchor,
5714                        position,
5715                        &mut diff_transforms_cursor,
5716                        &excerpt.buffer,
5717                    ));
5718                }
5719            } else {
5720                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5721                let position = self.resolve_summary_for_min_or_max_anchor(
5722                    &Anchor::max(),
5723                    excerpt_start_position,
5724                    &mut diff_transforms_cursor,
5725                );
5726                summaries.extend(excerpt_anchors.map(|_| position));
5727            }
5728        }
5729
5730        summaries
5731    }
5732
5733    pub fn dimensions_from_points<'a, MBD>(
5734        &'a self,
5735        points: impl 'a + IntoIterator<Item = Point>,
5736    ) -> impl 'a + Iterator<Item = MBD>
5737    where
5738        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5739    {
5740        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5741        cursor.seek(&DimensionPair {
5742            key: Point::default(),
5743            value: None,
5744        });
5745        let mut points = points.into_iter();
5746        iter::from_fn(move || {
5747            let point = points.next()?;
5748
5749            cursor.seek_forward(&DimensionPair {
5750                key: point,
5751                value: None,
5752            });
5753
5754            if let Some(region) = cursor.region() {
5755                let overshoot = point - region.range.start.key;
5756                let buffer_point = region.buffer_range.start + overshoot;
5757                let mut position = region.range.start.value.unwrap();
5758                position.add_text_dim(
5759                    &region
5760                        .buffer
5761                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5762                );
5763                if point == region.range.end.key && region.has_trailing_newline {
5764                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5765                }
5766                Some(position)
5767            } else {
5768                Some(MBD::from_summary(&self.text_summary()))
5769            }
5770        })
5771    }
5772
5773    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5774    where
5775        I: 'a + IntoIterator<Item = &'a Anchor>,
5776    {
5777        let mut anchors = anchors.into_iter().enumerate().peekable();
5778        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5779        cursor.next();
5780
5781        let mut result = Vec::new();
5782
5783        while let Some((_, anchor)) = anchors.peek() {
5784            let old_excerpt_id = anchor.excerpt_id;
5785
5786            // Find the location where this anchor's excerpt should be.
5787            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5788            cursor.seek_forward(&Some(old_locator), Bias::Left);
5789
5790            let next_excerpt = cursor.item();
5791            let prev_excerpt = cursor.prev_item();
5792
5793            // Process all of the anchors for this excerpt.
5794            while let Some((anchor_ix, &anchor)) =
5795                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5796            {
5797                let mut anchor = anchor;
5798
5799                // Leave min and max anchors unchanged if invalid or
5800                // if the old excerpt still exists at this location
5801                let mut kept_position = next_excerpt
5802                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5803                    || old_excerpt_id == ExcerptId::max()
5804                    || old_excerpt_id == ExcerptId::min();
5805
5806                // If the old excerpt no longer exists at this location, then attempt to
5807                // find an equivalent position for this anchor in an adjacent excerpt.
5808                if !kept_position {
5809                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5810                        if excerpt.contains(&anchor) {
5811                            anchor.excerpt_id = excerpt.id;
5812                            kept_position = true;
5813                            break;
5814                        }
5815                    }
5816                }
5817
5818                // If there's no adjacent excerpt that contains the anchor's position,
5819                // then report that the anchor has lost its position.
5820                if !kept_position {
5821                    anchor = if let Some(excerpt) = next_excerpt {
5822                        let mut text_anchor = excerpt
5823                            .range
5824                            .context
5825                            .start
5826                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5827                        if text_anchor
5828                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5829                            .is_gt()
5830                        {
5831                            text_anchor = excerpt.range.context.end;
5832                        }
5833                        Anchor::in_buffer(excerpt.id, text_anchor)
5834                    } else if let Some(excerpt) = prev_excerpt {
5835                        let mut text_anchor = excerpt
5836                            .range
5837                            .context
5838                            .end
5839                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5840                        if text_anchor
5841                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5842                            .is_lt()
5843                        {
5844                            text_anchor = excerpt.range.context.start;
5845                        }
5846                        Anchor::in_buffer(excerpt.id, text_anchor)
5847                    } else if anchor.text_anchor.bias == Bias::Left {
5848                        Anchor::min()
5849                    } else {
5850                        Anchor::max()
5851                    };
5852                }
5853
5854                result.push((anchor_ix, anchor, kept_position));
5855            }
5856        }
5857        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5858        result
5859    }
5860
5861    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5862        self.anchor_at(position, Bias::Left)
5863    }
5864
5865    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5866        self.anchor_at(position, Bias::Right)
5867    }
5868
5869    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5870        let offset = position.to_offset(self);
5871
5872        // Find the given position in the diff transforms. Determine the corresponding
5873        // offset in the excerpts, and whether the position is within a deleted hunk.
5874        let mut diff_transforms = self
5875            .diff_transforms
5876            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5877        diff_transforms.seek(&offset, Bias::Right);
5878
5879        if offset == diff_transforms.start().0
5880            && bias == Bias::Left
5881            && let Some(prev_item) = diff_transforms.prev_item()
5882            && let DiffTransform::DeletedHunk { .. } = prev_item
5883        {
5884            diff_transforms.prev();
5885        }
5886        let offset_in_transform = offset - diff_transforms.start().0;
5887        let mut excerpt_offset = diff_transforms.start().1;
5888        let mut diff_base_anchor = None;
5889        if let Some(DiffTransform::DeletedHunk {
5890            buffer_id,
5891            base_text_byte_range,
5892            has_trailing_newline,
5893            ..
5894        }) = diff_transforms.item()
5895        {
5896            let diff = self.diffs.get(buffer_id).expect("missing diff");
5897            if offset_in_transform > base_text_byte_range.len() {
5898                debug_assert!(*has_trailing_newline);
5899                bias = Bias::Right;
5900            } else {
5901                diff_base_anchor = Some(
5902                    diff.base_text()
5903                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5904                );
5905                bias = Bias::Left;
5906            }
5907        } else {
5908            excerpt_offset += MultiBufferOffset(offset_in_transform);
5909        };
5910
5911        let mut excerpts = self
5912            .excerpts
5913            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5914        excerpts.seek(&excerpt_offset, Bias::Right);
5915        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5916            excerpts.prev();
5917        }
5918        if let Some(excerpt) = excerpts.item() {
5919            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5920            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5921                overshoot -= 1;
5922                bias = Bias::Right;
5923            }
5924
5925            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5926            let text_anchor =
5927                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5928            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5929            match diff_base_anchor {
5930                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5931                None => anchor,
5932            }
5933        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5934        {
5935            Anchor::min()
5936        } else {
5937            Anchor::max()
5938        }
5939    }
5940
5941    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5942    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5943        let (excerpt, buffer, _) = self.as_singleton()?;
5944        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5945            Some(Anchor::in_buffer(excerpt, text_anchor))
5946        } else {
5947            None
5948        }
5949    }
5950
5951    /// Returns an anchor for the given excerpt and text anchor,
5952    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5953    pub fn anchor_range_in_excerpt(
5954        &self,
5955        excerpt_id: ExcerptId,
5956        text_anchor: Range<text::Anchor>,
5957    ) -> Option<Range<Anchor>> {
5958        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5959
5960        Some(
5961            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5962                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5963        )
5964    }
5965
5966    /// Returns an anchor for the given excerpt and text anchor,
5967    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5968    pub fn anchor_in_excerpt(
5969        &self,
5970        excerpt_id: ExcerptId,
5971        text_anchor: text::Anchor,
5972    ) -> Option<Anchor> {
5973        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5974        Self::anchor_in_excerpt_(excerpt, text_anchor)
5975    }
5976
5977    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5978    pub fn anchors_in_excerpt(
5979        &self,
5980        excerpt_id: ExcerptId,
5981        text_anchors: impl IntoIterator<Item = text::Anchor>,
5982    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5983        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5984        Some(
5985            text_anchors
5986                .into_iter()
5987                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5988        )
5989    }
5990
5991    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5992        match text_anchor.buffer_id {
5993            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5994            Some(_) => return None,
5995            None if text_anchor.is_max() || text_anchor.is_min() => {
5996                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5997            }
5998            None => return None,
5999        }
6000
6001        let context = &excerpt.range.context;
6002        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6003            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6004        {
6005            return None;
6006        }
6007
6008        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6009    }
6010
6011    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6012        Some(self.excerpt(excerpt_id)?.range.context.clone())
6013    }
6014
6015    pub fn excerpt_range_for_excerpt(
6016        &self,
6017        excerpt_id: ExcerptId,
6018    ) -> Option<ExcerptRange<text::Anchor>> {
6019        Some(self.excerpt(excerpt_id)?.range.clone())
6020    }
6021
6022    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6023        if anchor.is_min() || anchor.is_max() {
6024            // todo(lw): should be `!self.is_empty()`
6025            true
6026        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6027            excerpt.buffer.can_resolve(&anchor.text_anchor)
6028        } else {
6029            false
6030        }
6031    }
6032
6033    pub fn excerpts(
6034        &self,
6035    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6036        self.excerpts
6037            .iter()
6038            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6039    }
6040
6041    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6042    where
6043        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6044        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6045    {
6046        let excerpts = self.excerpts.cursor(());
6047        let diff_transforms = self.diff_transforms.cursor(());
6048        MultiBufferCursor {
6049            excerpts,
6050            diff_transforms,
6051            diffs: &self.diffs,
6052            cached_region: OnceCell::new(),
6053        }
6054    }
6055
6056    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6057        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6058        let mut excerpts = self
6059            .excerpts
6060            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6061        excerpts.seek(&Some(start_locator), Bias::Left);
6062        excerpts.prev();
6063
6064        let mut diff_transforms = self
6065            .diff_transforms
6066            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6067        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6068        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6069            diff_transforms.next();
6070        }
6071
6072        let excerpt = excerpts.item()?;
6073        Some(MultiBufferExcerpt {
6074            excerpt,
6075            offset: diff_transforms.start().output_dimension.0,
6076            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6077            excerpt_offset: excerpts.start().1,
6078            diff_transforms,
6079        })
6080    }
6081
6082    pub fn excerpt_boundaries_in_range<R, T>(
6083        &self,
6084        range: R,
6085    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6086    where
6087        R: RangeBounds<T>,
6088        T: ToOffset,
6089    {
6090        let start_offset;
6091        let start = match range.start_bound() {
6092            Bound::Included(start) => {
6093                start_offset = start.to_offset(self);
6094                Bound::Included(start_offset)
6095            }
6096            Bound::Excluded(_) => {
6097                panic!("not supported")
6098            }
6099            Bound::Unbounded => {
6100                start_offset = MultiBufferOffset::ZERO;
6101                Bound::Unbounded
6102            }
6103        };
6104        let end = match range.end_bound() {
6105            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6106            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6107            Bound::Unbounded => Bound::Unbounded,
6108        };
6109        let bounds = (start, end);
6110        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6111        cursor.seek(&DimensionPair {
6112            key: start_offset,
6113            value: None,
6114        });
6115
6116        if cursor
6117            .fetch_excerpt_with_range()
6118            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6119        {
6120            cursor.prev_excerpt();
6121        } else {
6122            cursor.seek_to_start_of_current_excerpt();
6123        }
6124        let mut prev_region = cursor
6125            .fetch_excerpt_with_range()
6126            .map(|(excerpt, _)| excerpt);
6127
6128        cursor.next_excerpt_forwards();
6129
6130        iter::from_fn(move || {
6131            loop {
6132                if self.singleton {
6133                    return None;
6134                }
6135
6136                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6137                cursor.next_excerpt_forwards();
6138                if !bounds.contains(&next_range.start.key) {
6139                    prev_region = Some(next_excerpt);
6140                    continue;
6141                }
6142
6143                let next_region_start = next_range.start.value.unwrap();
6144                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6145                    range.start.value.unwrap()
6146                } else {
6147                    self.max_point()
6148                };
6149
6150                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6151                    id: region.id,
6152                    buffer: region.buffer.clone(),
6153                    buffer_id: region.buffer_id,
6154                    range: region.range.clone(),
6155                    end_row: MultiBufferRow(next_region_start.row),
6156                });
6157
6158                let next = ExcerptInfo {
6159                    id: next_excerpt.id,
6160                    buffer: next_excerpt.buffer.clone(),
6161                    buffer_id: next_excerpt.buffer_id,
6162                    range: next_excerpt.range.clone(),
6163                    end_row: if next_excerpt.has_trailing_newline {
6164                        MultiBufferRow(next_region_end.row - 1)
6165                    } else {
6166                        MultiBufferRow(next_region_end.row)
6167                    },
6168                };
6169
6170                let row = MultiBufferRow(next_region_start.row);
6171
6172                prev_region = Some(next_excerpt);
6173
6174                return Some(ExcerptBoundary { row, prev, next });
6175            }
6176        })
6177    }
6178
6179    pub fn edit_count(&self) -> usize {
6180        self.edit_count
6181    }
6182
6183    pub fn non_text_state_update_count(&self) -> usize {
6184        self.non_text_state_update_count
6185    }
6186
6187    /// Returns the smallest enclosing bracket ranges containing the given range or
6188    /// None if no brackets contain range or the range is not contained in a single
6189    /// excerpt
6190    ///
6191    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6192    #[ztracing::instrument(skip_all)]
6193    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6194        &self,
6195        range: Range<T>,
6196        range_filter: Option<
6197            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6198        >,
6199    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6200        let range = range.start.to_offset(self)..range.end.to_offset(self);
6201        let mut excerpt = self.excerpt_containing(range.clone())?;
6202        let buffer = excerpt.buffer();
6203        let excerpt_buffer_range = excerpt.buffer_range();
6204
6205        // Filter to ranges contained in the excerpt
6206        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6207            excerpt_buffer_range.contains(&BufferOffset(open.start))
6208                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6209                && range_filter.is_none_or(|filter| {
6210                    filter(
6211                        buffer,
6212                        BufferOffset(open.start)..BufferOffset(close.end),
6213                        BufferOffset(close.start)..BufferOffset(close.end),
6214                    )
6215                })
6216        };
6217
6218        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6219            excerpt.map_range_to_buffer(range),
6220            Some(&range_filter),
6221        )?;
6222
6223        Some((
6224            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6225            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6226        ))
6227    }
6228
6229    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6230    /// not contained in a single excerpt
6231    pub fn enclosing_bracket_ranges<T: ToOffset>(
6232        &self,
6233        range: Range<T>,
6234    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6235    {
6236        let range = range.start.to_offset(self)..range.end.to_offset(self);
6237        let mut excerpt = self.excerpt_containing(range.clone())?;
6238
6239        Some(
6240            excerpt
6241                .buffer()
6242                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6243                .filter_map(move |pair| {
6244                    let open_range =
6245                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6246                    let close_range =
6247                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6248                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6249                        Some((
6250                            excerpt.map_range_from_buffer(open_range),
6251                            excerpt.map_range_from_buffer(close_range),
6252                        ))
6253                    } else {
6254                        None
6255                    }
6256                }),
6257        )
6258    }
6259
6260    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6261    /// not contained in a single excerpt
6262    pub fn text_object_ranges<T: ToOffset>(
6263        &self,
6264        range: Range<T>,
6265        options: TreeSitterOptions,
6266    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6267        let range = range.start.to_offset(self)..range.end.to_offset(self);
6268        self.excerpt_containing(range.clone())
6269            .map(|mut excerpt| {
6270                excerpt
6271                    .buffer()
6272                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6273                    .filter_map(move |(range, text_object)| {
6274                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6275                        if excerpt.contains_buffer_range(range.clone()) {
6276                            Some((excerpt.map_range_from_buffer(range), text_object))
6277                        } else {
6278                            None
6279                        }
6280                    })
6281            })
6282            .into_iter()
6283            .flatten()
6284    }
6285
6286    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6287    /// not contained in a single excerpt
6288    pub fn bracket_ranges<T: ToOffset>(
6289        &self,
6290        range: Range<T>,
6291    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6292    {
6293        let range = range.start.to_offset(self)..range.end.to_offset(self);
6294        let mut excerpt = self.excerpt_containing(range.clone())?;
6295        Some(
6296            excerpt
6297                .buffer()
6298                .bracket_ranges(excerpt.map_range_to_buffer(range))
6299                .filter_map(move |pair| {
6300                    let open_range =
6301                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6302                    let close_range =
6303                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6304                    excerpt
6305                        .contains_buffer_range(open_range.start..close_range.end)
6306                        .then(|| BracketMatch {
6307                            open_range: excerpt.map_range_from_buffer(open_range),
6308                            close_range: excerpt.map_range_from_buffer(close_range),
6309                            color_index: pair.color_index,
6310                            newline_only: pair.newline_only,
6311                            syntax_layer_depth: pair.syntax_layer_depth,
6312                        })
6313                })
6314                .map(BracketMatch::bracket_ranges),
6315        )
6316    }
6317
6318    pub fn redacted_ranges<'a, T: ToOffset>(
6319        &'a self,
6320        range: Range<T>,
6321        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6322    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6323        let range = range.start.to_offset(self)..range.end.to_offset(self);
6324        self.lift_buffer_metadata(range, move |buffer, range| {
6325            if redaction_enabled(buffer.file()) {
6326                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6327            } else {
6328                None
6329            }
6330        })
6331        .map(|(range, _, _)| range)
6332    }
6333
6334    pub fn runnable_ranges(
6335        &self,
6336        range: Range<Anchor>,
6337    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6338        let range = range.start.to_offset(self)..range.end.to_offset(self);
6339        self.lift_buffer_metadata(range, move |buffer, range| {
6340            Some(
6341                buffer
6342                    .runnable_ranges(range.clone())
6343                    .filter(move |runnable| {
6344                        runnable.run_range.start >= range.start
6345                            && runnable.run_range.end < range.end
6346                    })
6347                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6348            )
6349        })
6350        .map(|(run_range, runnable, _)| (run_range, runnable))
6351    }
6352
6353    pub fn line_indents(
6354        &self,
6355        start_row: MultiBufferRow,
6356        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6357    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6358        let max_point = self.max_point();
6359        let mut cursor = self.cursor::<Point, Point>();
6360        cursor.seek(&Point::new(start_row.0, 0));
6361        iter::from_fn(move || {
6362            let mut region = cursor.region()?;
6363            while !buffer_filter(&region.excerpt.buffer) {
6364                cursor.next();
6365                region = cursor.region()?;
6366            }
6367            let region = cursor.region()?;
6368            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6369            let buffer_start_row =
6370                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6371
6372            let buffer_end_row = if region.is_main_buffer
6373                && (region.has_trailing_newline || region.range.end == max_point)
6374            {
6375                region.buffer_range.end.row
6376            } else {
6377                region.buffer_range.end.row.saturating_sub(1)
6378            };
6379
6380            let line_indents = region
6381                .buffer
6382                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6383            let region_buffer_row = region.buffer_range.start.row;
6384            let region_row = region.range.start.row;
6385            let region_buffer = &region.excerpt.buffer;
6386            cursor.next();
6387            Some(line_indents.map(move |(buffer_row, indent)| {
6388                let row = region_row + (buffer_row - region_buffer_row);
6389                (MultiBufferRow(row), indent, region_buffer.as_ref())
6390            }))
6391        })
6392        .flatten()
6393    }
6394
6395    pub fn reversed_line_indents(
6396        &self,
6397        end_row: MultiBufferRow,
6398        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6399    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6400        let max_point = self.max_point();
6401        let mut cursor = self.cursor::<Point, Point>();
6402        cursor.seek(&Point::new(end_row.0, 0));
6403        iter::from_fn(move || {
6404            let mut region = cursor.region()?;
6405            while !buffer_filter(&region.excerpt.buffer) {
6406                cursor.prev();
6407                region = cursor.region()?;
6408            }
6409            let region = cursor.region()?;
6410
6411            let buffer_start_row = region.buffer_range.start.row;
6412            let buffer_end_row = if region.is_main_buffer
6413                && (region.has_trailing_newline || region.range.end == max_point)
6414            {
6415                region.buffer_range.end.row + 1
6416            } else {
6417                region.buffer_range.end.row
6418            };
6419
6420            let overshoot = end_row.0 - region.range.start.row;
6421            let buffer_end_row =
6422                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6423
6424            let line_indents = region
6425                .buffer
6426                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6427            let region_buffer_row = region.buffer_range.start.row;
6428            let region_row = region.range.start.row;
6429            let region_buffer = &region.excerpt.buffer;
6430            cursor.prev();
6431            Some(line_indents.map(move |(buffer_row, indent)| {
6432                let row = region_row + (buffer_row - region_buffer_row);
6433                (MultiBufferRow(row), indent, region_buffer.as_ref())
6434            }))
6435        })
6436        .flatten()
6437    }
6438
6439    pub async fn enclosing_indent(
6440        &self,
6441        mut target_row: MultiBufferRow,
6442    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6443        let max_row = MultiBufferRow(self.max_point().row);
6444        if target_row >= max_row {
6445            return None;
6446        }
6447
6448        let mut target_indent = self.line_indent_for_row(target_row);
6449
6450        // If the current row is at the start of an indented block, we want to return this
6451        // block as the enclosing indent.
6452        if !target_indent.is_line_empty() && target_row < max_row {
6453            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6454            if !next_line_indent.is_line_empty()
6455                && target_indent.raw_len() < next_line_indent.raw_len()
6456            {
6457                target_indent = next_line_indent;
6458                target_row.0 += 1;
6459            }
6460        }
6461
6462        const SEARCH_ROW_LIMIT: u32 = 25000;
6463        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6464        const YIELD_INTERVAL: u32 = 100;
6465
6466        let mut accessed_row_counter = 0;
6467
6468        // If there is a blank line at the current row, search for the next non indented lines
6469        if target_indent.is_line_empty() {
6470            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6471            let end =
6472                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6473
6474            let mut non_empty_line_above = None;
6475            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6476                if row < start {
6477                    break;
6478                }
6479                accessed_row_counter += 1;
6480                if accessed_row_counter == YIELD_INTERVAL {
6481                    accessed_row_counter = 0;
6482                    yield_now().await;
6483                }
6484                if !indent.is_line_empty() {
6485                    non_empty_line_above = Some((row, indent));
6486                    break;
6487                }
6488            }
6489
6490            let mut non_empty_line_below = None;
6491            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6492                if row > end {
6493                    break;
6494                }
6495                accessed_row_counter += 1;
6496                if accessed_row_counter == YIELD_INTERVAL {
6497                    accessed_row_counter = 0;
6498                    yield_now().await;
6499                }
6500                if !indent.is_line_empty() {
6501                    non_empty_line_below = Some((row, indent));
6502                    break;
6503                }
6504            }
6505
6506            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6507                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6508                    if above_indent.raw_len() >= below_indent.raw_len() {
6509                        (above_row, above_indent)
6510                    } else {
6511                        (below_row, below_indent)
6512                    }
6513                }
6514                (Some(above), None) => above,
6515                (None, Some(below)) => below,
6516                _ => return None,
6517            };
6518
6519            target_indent = indent;
6520            target_row = row;
6521        }
6522
6523        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6524        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6525
6526        let mut start_indent = None;
6527        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6528            if row < start {
6529                break;
6530            }
6531            accessed_row_counter += 1;
6532            if accessed_row_counter == YIELD_INTERVAL {
6533                accessed_row_counter = 0;
6534                yield_now().await;
6535            }
6536            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6537                start_indent = Some((row, indent));
6538                break;
6539            }
6540        }
6541        let (start_row, start_indent_size) = start_indent?;
6542
6543        let mut end_indent = (end, None);
6544        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6545            if row > end {
6546                break;
6547            }
6548            accessed_row_counter += 1;
6549            if accessed_row_counter == YIELD_INTERVAL {
6550                accessed_row_counter = 0;
6551                yield_now().await;
6552            }
6553            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6554                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6555                break;
6556            }
6557        }
6558        let (end_row, end_indent_size) = end_indent;
6559
6560        let indent = if let Some(end_indent_size) = end_indent_size {
6561            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6562                start_indent_size
6563            } else {
6564                end_indent_size
6565            }
6566        } else {
6567            start_indent_size
6568        };
6569
6570        Some((start_row..end_row, indent))
6571    }
6572
6573    pub fn indent_guides_in_range<T: ToPoint>(
6574        &self,
6575        range: Range<T>,
6576        ignore_disabled_for_language: bool,
6577        cx: &App,
6578    ) -> impl Iterator<Item = IndentGuide> {
6579        let range = range.start.to_point(self)..range.end.to_point(self);
6580        let start_row = MultiBufferRow(range.start.row);
6581        let end_row = MultiBufferRow(range.end.row);
6582
6583        let mut row_indents = self.line_indents(start_row, |buffer| {
6584            let settings =
6585                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6586            settings.indent_guides.enabled || ignore_disabled_for_language
6587        });
6588
6589        let mut result = Vec::new();
6590        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6591
6592        let mut prev_settings = None;
6593        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6594            if first_row > end_row {
6595                break;
6596            }
6597            let current_depth = indent_stack.len() as u32;
6598
6599            // Avoid retrieving the language settings repeatedly for every buffer row.
6600            if let Some((prev_buffer_id, _)) = &prev_settings
6601                && prev_buffer_id != &buffer.remote_id()
6602            {
6603                prev_settings.take();
6604            }
6605            let settings = &prev_settings
6606                .get_or_insert_with(|| {
6607                    (
6608                        buffer.remote_id(),
6609                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6610                    )
6611                })
6612                .1;
6613            let tab_size = settings.tab_size.get();
6614
6615            // When encountering empty, continue until found useful line indent
6616            // then add to the indent stack with the depth found
6617            let mut found_indent = false;
6618            let mut last_row = first_row;
6619            if line_indent.is_line_blank() {
6620                while !found_indent {
6621                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6622                        break;
6623                    };
6624                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6625                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6626                        break;
6627                    }
6628
6629                    if new_line_indent.is_line_blank() {
6630                        continue;
6631                    }
6632                    last_row = target_row.min(end_row);
6633                    line_indent = new_line_indent;
6634                    found_indent = true;
6635                    break;
6636                }
6637            } else {
6638                found_indent = true
6639            }
6640
6641            let depth = if found_indent {
6642                line_indent.len(tab_size) / tab_size
6643            } else {
6644                0
6645            };
6646
6647            match depth.cmp(&current_depth) {
6648                cmp::Ordering::Less => {
6649                    for _ in 0..(current_depth - depth) {
6650                        let mut indent = indent_stack.pop().unwrap();
6651                        if last_row != first_row {
6652                            // In this case, we landed on an empty row, had to seek forward,
6653                            // and discovered that the indent we where on is ending.
6654                            // This means that the last display row must
6655                            // be on line that ends this indent range, so we
6656                            // should display the range up to the first non-empty line
6657                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6658                        }
6659
6660                        result.push(indent)
6661                    }
6662                }
6663                cmp::Ordering::Greater => {
6664                    for next_depth in current_depth..depth {
6665                        indent_stack.push(IndentGuide {
6666                            buffer_id: buffer.remote_id(),
6667                            start_row: first_row,
6668                            end_row: last_row,
6669                            depth: next_depth,
6670                            tab_size,
6671                            settings: settings.indent_guides.clone(),
6672                        });
6673                    }
6674                }
6675                _ => {}
6676            }
6677
6678            for indent in indent_stack.iter_mut() {
6679                indent.end_row = last_row;
6680            }
6681        }
6682
6683        result.extend(indent_stack);
6684        result.into_iter()
6685    }
6686
6687    pub fn trailing_excerpt_update_count(&self) -> usize {
6688        self.trailing_excerpt_update_count
6689    }
6690
6691    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6692        self.point_to_buffer_offset(point)
6693            .and_then(|(buffer, _)| buffer.file())
6694    }
6695
6696    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6697        self.point_to_buffer_offset(offset)
6698            .and_then(|(buffer, offset)| buffer.language_at(offset))
6699    }
6700
6701    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6702        self.excerpts
6703            .first()
6704            .map(|excerpt| &excerpt.buffer)
6705            .map(|buffer| {
6706                language_settings(
6707                    buffer.language().map(|language| language.name()),
6708                    buffer.file(),
6709                    cx,
6710                )
6711            })
6712            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6713    }
6714
6715    pub fn language_settings_at<'a, T: ToOffset>(
6716        &'a self,
6717        point: T,
6718        cx: &'a App,
6719    ) -> Cow<'a, LanguageSettings> {
6720        let mut language = None;
6721        let mut file = None;
6722        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6723            language = buffer.language_at(offset);
6724            file = buffer.file();
6725        }
6726        language_settings(language.map(|l| l.name()), file, cx)
6727    }
6728
6729    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6730        self.point_to_buffer_offset(point)
6731            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6732    }
6733
6734    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6735        self.point_to_buffer_offset(point)
6736            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6737            .unwrap_or_default()
6738    }
6739
6740    pub fn language_indent_size_at<T: ToOffset>(
6741        &self,
6742        position: T,
6743        cx: &App,
6744    ) -> Option<IndentSize> {
6745        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6746        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6747    }
6748
6749    pub fn is_dirty(&self) -> bool {
6750        self.is_dirty
6751    }
6752
6753    pub fn has_deleted_file(&self) -> bool {
6754        self.has_deleted_file
6755    }
6756
6757    pub fn has_conflict(&self) -> bool {
6758        self.has_conflict
6759    }
6760
6761    pub fn has_diagnostics(&self) -> bool {
6762        self.excerpts
6763            .iter()
6764            .any(|excerpt| excerpt.buffer.has_diagnostics())
6765    }
6766
6767    pub fn diagnostic_group(
6768        &self,
6769        buffer_id: BufferId,
6770        group_id: usize,
6771    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6772        self.lift_buffer_metadata::<Point, _, _>(
6773            Point::zero()..self.max_point(),
6774            move |buffer, range| {
6775                if buffer.remote_id() != buffer_id {
6776                    return None;
6777                };
6778                Some(
6779                    buffer
6780                        .diagnostics_in_range(range, false)
6781                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6782                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6783                )
6784            },
6785        )
6786        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6787    }
6788
6789    pub fn diagnostics_in_range<'a, MBD>(
6790        &'a self,
6791        range: Range<MBD>,
6792    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6793    where
6794        MBD::TextDimension: 'a
6795            + text::ToOffset
6796            + text::FromAnchor
6797            + Sub<Output = MBD::TextDimension>
6798            + fmt::Debug
6799            + ops::Add<Output = MBD::TextDimension>
6800            + ops::AddAssign
6801            + Ord,
6802        MBD: MultiBufferDimension
6803            + Ord
6804            + Sub<Output = MBD::TextDimension>
6805            + ops::Add<MBD::TextDimension, Output = MBD>
6806            + ops::AddAssign<MBD::TextDimension>
6807            + 'a,
6808    {
6809        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6810            Some(
6811                buffer
6812                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6813                    .map(|entry| (entry.range, entry.diagnostic)),
6814            )
6815        })
6816        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6817    }
6818
6819    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6820        &'a self,
6821        range: Range<MBD>,
6822    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6823    where
6824        MBD: MultiBufferDimension
6825            + Ord
6826            + Sub<Output = MBD::TextDimension>
6827            + ops::Add<MBD::TextDimension, Output = MBD>
6828            + ops::AddAssign<MBD::TextDimension>,
6829        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6830            + ops::Add<Output = MBD::TextDimension>
6831            + text::ToOffset
6832            + text::FromAnchor
6833            + AddAssign<MBD::TextDimension>
6834            + Ord,
6835    {
6836        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6837            Some(
6838                buffer
6839                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6840                    .map(|entry| (entry.range, entry.diagnostic)),
6841            )
6842        })
6843        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6844    }
6845
6846    pub fn syntax_ancestor<T: ToOffset>(
6847        &self,
6848        range: Range<T>,
6849    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6850        let range = range.start.to_offset(self)..range.end.to_offset(self);
6851        let mut excerpt = self.excerpt_containing(range.clone())?;
6852        let node = excerpt
6853            .buffer()
6854            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6855        let node_range = node.byte_range();
6856        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6857        if !excerpt.contains_buffer_range(node_range.clone()) {
6858            return None;
6859        };
6860        Some((node, excerpt.map_range_from_buffer(node_range)))
6861    }
6862
6863    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6864        let (excerpt_id, _, buffer) = self.as_singleton()?;
6865        let outline = buffer.outline(theme);
6866        Some(Outline::new(
6867            outline
6868                .items
6869                .into_iter()
6870                .flat_map(|item| {
6871                    Some(OutlineItem {
6872                        depth: item.depth,
6873                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6874                        source_range_for_text: self
6875                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6876                        text: item.text,
6877                        highlight_ranges: item.highlight_ranges,
6878                        name_ranges: item.name_ranges,
6879                        body_range: item.body_range.and_then(|body_range| {
6880                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6881                        }),
6882                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6883                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6884                        }),
6885                    })
6886                })
6887                .collect(),
6888        ))
6889    }
6890
6891    pub fn symbols_containing<T: ToOffset>(
6892        &self,
6893        offset: T,
6894        theme: Option<&SyntaxTheme>,
6895    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6896        let anchor = self.anchor_before(offset);
6897        let excerpt @ &Excerpt {
6898            id: excerpt_id,
6899            buffer_id,
6900            ref buffer,
6901            ..
6902        } = self.excerpt(anchor.excerpt_id)?;
6903        if cfg!(debug_assertions) {
6904            match anchor.text_anchor.buffer_id {
6905                // we clearly are hitting this according to sentry, but in what situations can this occur?
6906                Some(anchor_buffer_id) => {
6907                    assert_eq!(
6908                        anchor_buffer_id, buffer_id,
6909                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6910                    )
6911                }
6912                None => assert!(anchor.is_max()),
6913            }
6914        };
6915        Some((
6916            buffer_id,
6917            buffer
6918                .symbols_containing(anchor.text_anchor, theme)
6919                .into_iter()
6920                .flat_map(|item| {
6921                    Some(OutlineItem {
6922                        depth: item.depth,
6923                        source_range_for_text: Anchor::range_in_buffer(
6924                            excerpt_id,
6925                            item.source_range_for_text,
6926                        ),
6927                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6928                        text: item.text,
6929                        highlight_ranges: item.highlight_ranges,
6930                        name_ranges: item.name_ranges,
6931                        body_range: item
6932                            .body_range
6933                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6934                        annotation_range: item
6935                            .annotation_range
6936                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6937                    })
6938                })
6939                .collect(),
6940        ))
6941    }
6942
6943    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6944        self.try_excerpt_locator_for_id(id)
6945            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6946    }
6947
6948    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6949        if id == ExcerptId::min() {
6950            Some(Locator::min_ref())
6951        } else if id == ExcerptId::max() {
6952            Some(Locator::max_ref())
6953        } else {
6954            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6955            if let Some(entry) = item
6956                && entry.id == id
6957            {
6958                return Some(&entry.locator);
6959            }
6960            None
6961        }
6962    }
6963
6964    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6965    fn excerpt_locators_for_ids(
6966        &self,
6967        ids: impl IntoIterator<Item = ExcerptId>,
6968    ) -> SmallVec<[Locator; 1]> {
6969        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6970        sorted_ids.sort_unstable();
6971        sorted_ids.dedup();
6972        let mut locators = SmallVec::new();
6973
6974        while sorted_ids.last() == Some(&ExcerptId::max()) {
6975            sorted_ids.pop();
6976            locators.push(Locator::max());
6977        }
6978
6979        let mut sorted_ids = sorted_ids.into_iter().peekable();
6980        locators.extend(
6981            sorted_ids
6982                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6983                .map(|_| Locator::min()),
6984        );
6985
6986        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6987        for id in sorted_ids {
6988            if cursor.seek_forward(&id, Bias::Left) {
6989                locators.push(cursor.item().unwrap().locator.clone());
6990            } else {
6991                panic!("invalid excerpt id {:?}", id);
6992            }
6993        }
6994
6995        locators.sort_unstable();
6996        locators
6997    }
6998
6999    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
7000        Some(self.excerpt(excerpt_id)?.buffer_id)
7001    }
7002
7003    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7004        Some(&self.excerpt(excerpt_id)?.buffer)
7005    }
7006
7007    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7008        let mut cursor = self
7009            .excerpts
7010            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7011        let locator = self.excerpt_locator_for_id(excerpt_id);
7012        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7013        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7014            sought_exact = true;
7015            cursor.prev();
7016        } else if excerpt_id == ExcerptId::min() {
7017            sought_exact = true;
7018        }
7019        if sought_exact {
7020            let start = cursor.start().1;
7021            let end = cursor.end().1;
7022            let mut diff_transforms = self
7023                .diff_transforms
7024                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7025            diff_transforms.seek(&start, Bias::Left);
7026            let overshoot = start - diff_transforms.start().0;
7027            let start = diff_transforms.start().1 + overshoot;
7028            diff_transforms.seek(&end, Bias::Right);
7029            let overshoot = end - diff_transforms.start().0;
7030            let end = diff_transforms.start().1 + overshoot;
7031            Some(start.0..end.0)
7032        } else {
7033            None
7034        }
7035    }
7036
7037    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7038    /// to have the latest excerpt id for the one passed in and will also remap
7039    /// `ExcerptId::max()` to the corresponding excertp ID.
7040    ///
7041    /// Callers of this function should generally use the resulting excerpt's `id` field
7042    /// afterwards.
7043    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7044        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7045        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7046        let (_, _, item) =
7047            self.excerpts
7048                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7049        if let Some(excerpt) = item
7050            && excerpt.id == excerpt_id
7051        {
7052            return Some(excerpt);
7053        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7054            return self.excerpts.last();
7055        }
7056        None
7057    }
7058
7059    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7060    pub fn excerpt_containing<T: ToOffset>(
7061        &self,
7062        range: Range<T>,
7063    ) -> Option<MultiBufferExcerpt<'_>> {
7064        let range = range.start.to_offset(self)..range.end.to_offset(self);
7065        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7066        cursor.seek(&range.start);
7067
7068        let start_excerpt = cursor.excerpt()?;
7069        if range.end != range.start {
7070            cursor.seek_forward(&range.end);
7071            if cursor.excerpt()?.id != start_excerpt.id {
7072                return None;
7073            }
7074        }
7075
7076        cursor.seek_to_start_of_current_excerpt();
7077        let region = cursor.region()?;
7078        let offset = region.range.start;
7079        let buffer_offset = start_excerpt.buffer_start_offset();
7080        let excerpt_offset = *cursor.excerpts.start();
7081        Some(MultiBufferExcerpt {
7082            diff_transforms: cursor.diff_transforms,
7083            excerpt: start_excerpt,
7084            offset,
7085            buffer_offset,
7086            excerpt_offset,
7087        })
7088    }
7089
7090    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7091        if let Some(id) = anchor.text_anchor.buffer_id {
7092            return Some(id);
7093        }
7094        let excerpt = self.excerpt_containing(anchor..anchor)?;
7095        Some(excerpt.buffer_id())
7096    }
7097
7098    pub fn selections_in_range<'a>(
7099        &'a self,
7100        range: &'a Range<Anchor>,
7101        include_local: bool,
7102    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7103        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7104        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7105        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7106        cursor.seek(start_locator, Bias::Left);
7107        cursor
7108            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7109            .flat_map(move |excerpt| {
7110                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7111                if excerpt.id == range.start.excerpt_id {
7112                    query_range.start = range.start.text_anchor;
7113                }
7114                if excerpt.id == range.end.excerpt_id {
7115                    query_range.end = range.end.text_anchor;
7116                }
7117
7118                excerpt
7119                    .buffer
7120                    .selections_in_range(query_range, include_local)
7121                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7122                        selections.map(move |selection| {
7123                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7124                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7125                            if range.start.cmp(&start, self).is_gt() {
7126                                start = range.start;
7127                            }
7128                            if range.end.cmp(&end, self).is_lt() {
7129                                end = range.end;
7130                            }
7131
7132                            (
7133                                replica_id,
7134                                line_mode,
7135                                cursor_shape,
7136                                Selection {
7137                                    id: selection.id,
7138                                    start,
7139                                    end,
7140                                    reversed: selection.reversed,
7141                                    goal: selection.goal,
7142                                },
7143                            )
7144                        })
7145                    })
7146            })
7147    }
7148
7149    pub fn show_headers(&self) -> bool {
7150        self.show_headers
7151    }
7152
7153    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7154        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7155    }
7156
7157    pub fn all_diff_hunks_expanded(&self) -> bool {
7158        self.all_diff_hunks_expanded
7159    }
7160
7161    /// Visually annotates a position or range with the `Debug` representation of a value. The
7162    /// callsite of this function is used as a key - previous annotations will be removed.
7163    #[cfg(debug_assertions)]
7164    #[track_caller]
7165    pub fn debug<V, R>(&self, ranges: &R, value: V)
7166    where
7167        R: debug::ToMultiBufferDebugRanges,
7168        V: std::fmt::Debug,
7169    {
7170        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7171    }
7172
7173    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7174    /// debug annotations with the same key will be removed. The key is also used to determine the
7175    /// annotation's color.
7176    #[cfg(debug_assertions)]
7177    #[track_caller]
7178    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7179    where
7180        K: std::hash::Hash + 'static,
7181        R: debug::ToMultiBufferDebugRanges,
7182        V: std::fmt::Debug,
7183    {
7184        let text_ranges = ranges
7185            .to_multi_buffer_debug_ranges(self)
7186            .into_iter()
7187            .flat_map(|range| {
7188                self.range_to_buffer_ranges(range.start..=range.end)
7189                    .into_iter()
7190                    .map(|(buffer, range, _excerpt_id)| {
7191                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7192                    })
7193            })
7194            .collect();
7195        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7196            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7197        });
7198    }
7199
7200    fn excerpt_edits_for_diff_change(
7201        &self,
7202        buffer_state: &BufferState,
7203        diff_change_range: Range<usize>,
7204    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7205        let mut excerpt_edits = Vec::new();
7206        for locator in &buffer_state.excerpts {
7207            let mut cursor = self
7208                .excerpts
7209                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7210            cursor.seek_forward(&Some(locator), Bias::Left);
7211            if let Some(excerpt) = cursor.item()
7212                && excerpt.locator == *locator
7213            {
7214                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7215                if diff_change_range.end < excerpt_buffer_range.start
7216                    || diff_change_range.start > excerpt_buffer_range.end
7217                {
7218                    continue;
7219                }
7220                let excerpt_start = cursor.start().1;
7221                let excerpt_len = excerpt.text_summary.len;
7222                let diff_change_start_in_excerpt = diff_change_range
7223                    .start
7224                    .saturating_sub(excerpt_buffer_range.start);
7225                let diff_change_end_in_excerpt = diff_change_range
7226                    .end
7227                    .saturating_sub(excerpt_buffer_range.start);
7228                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7229                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7230                excerpt_edits.push(Edit {
7231                    old: edit_start..edit_end,
7232                    new: edit_start..edit_end,
7233                });
7234            }
7235        }
7236        excerpt_edits
7237    }
7238}
7239
7240#[cfg(any(test, feature = "test-support"))]
7241impl MultiBufferSnapshot {
7242    pub fn random_byte_range(
7243        &self,
7244        start_offset: MultiBufferOffset,
7245        rng: &mut impl rand::Rng,
7246    ) -> Range<MultiBufferOffset> {
7247        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7248        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7249        start..end
7250    }
7251
7252    #[cfg(any(test, feature = "test-support"))]
7253    fn check_invariants(&self) {
7254        let excerpts = self.excerpts.items(());
7255        let excerpt_ids = self.excerpt_ids.items(());
7256
7257        for (ix, excerpt) in excerpts.iter().enumerate() {
7258            if ix == 0 {
7259                if excerpt.locator <= Locator::min() {
7260                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7261                }
7262            } else if excerpt.locator <= excerpts[ix - 1].locator {
7263                panic!("excerpts are out-of-order: {:?}", excerpts);
7264            }
7265        }
7266
7267        for (ix, entry) in excerpt_ids.iter().enumerate() {
7268            if ix == 0 {
7269                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7270                    panic!("invalid first excerpt id {:?}", entry.id);
7271                }
7272            } else if entry.id <= excerpt_ids[ix - 1].id {
7273                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7274            }
7275        }
7276
7277        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7278            panic!(
7279                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7280                self.excerpts.summary().text,
7281                self.diff_transforms.summary().input,
7282                self.diff_transforms.items(()),
7283            );
7284        }
7285
7286        let mut prev_transform: Option<&DiffTransform> = None;
7287        for item in self.diff_transforms.iter() {
7288            if let DiffTransform::BufferContent {
7289                summary,
7290                inserted_hunk_info,
7291            } = item
7292            {
7293                if let Some(DiffTransform::BufferContent {
7294                    inserted_hunk_info: prev_inserted_hunk_info,
7295                    ..
7296                }) = prev_transform
7297                    && *inserted_hunk_info == *prev_inserted_hunk_info
7298                {
7299                    panic!(
7300                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7301                        self.diff_transforms.items(())
7302                    );
7303                }
7304                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7305                    panic!("empty buffer content transform");
7306                }
7307            }
7308            prev_transform = Some(item);
7309        }
7310    }
7311}
7312
7313impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7314where
7315    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7316    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7317{
7318    #[instrument(skip_all)]
7319    fn seek(&mut self, position: &MBD) {
7320        let position = OutputDimension(*position);
7321        self.cached_region.take();
7322        self.diff_transforms.seek(&position, Bias::Right);
7323        if self.diff_transforms.item().is_none()
7324            && self.diff_transforms.start().output_dimension == position
7325        {
7326            self.diff_transforms.prev();
7327        }
7328
7329        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7330        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7331            let overshoot = position - self.diff_transforms.start().output_dimension;
7332            excerpt_position += overshoot;
7333        }
7334
7335        self.excerpts.seek(&excerpt_position, Bias::Right);
7336        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7337            self.excerpts.prev();
7338        }
7339    }
7340
7341    fn seek_forward(&mut self, position: &MBD) {
7342        let position = OutputDimension(*position);
7343        self.cached_region.take();
7344        self.diff_transforms.seek_forward(&position, Bias::Right);
7345        if self.diff_transforms.item().is_none()
7346            && self.diff_transforms.start().output_dimension == position
7347        {
7348            self.diff_transforms.prev();
7349        }
7350
7351        let overshoot = position - self.diff_transforms.start().output_dimension;
7352        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7353        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7354            excerpt_position += overshoot;
7355        }
7356
7357        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7358        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7359            self.excerpts.prev();
7360        }
7361    }
7362
7363    fn next_excerpt(&mut self) {
7364        self.excerpts.next();
7365        self.seek_to_start_of_current_excerpt();
7366    }
7367
7368    fn prev_excerpt(&mut self) {
7369        self.excerpts.prev();
7370        self.seek_to_start_of_current_excerpt();
7371    }
7372
7373    fn seek_to_start_of_current_excerpt(&mut self) {
7374        self.cached_region.take();
7375
7376        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7377            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7378            && self.diff_transforms.next_item().is_some()
7379        {
7380            self.diff_transforms.next();
7381        }
7382    }
7383
7384    fn next_excerpt_forwards(&mut self) {
7385        self.excerpts.next();
7386        self.seek_to_start_of_current_excerpt_forward();
7387    }
7388
7389    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7390        self.cached_region.take();
7391
7392        if self
7393            .diff_transforms
7394            .seek_forward(self.excerpts.start(), Bias::Left)
7395            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7396            && self.diff_transforms.next_item().is_some()
7397        {
7398            self.diff_transforms.next();
7399        }
7400    }
7401
7402    fn next(&mut self) {
7403        self.cached_region.take();
7404        match self
7405            .diff_transforms
7406            .end()
7407            .excerpt_dimension
7408            .cmp(&self.excerpts.end())
7409        {
7410            cmp::Ordering::Less => self.diff_transforms.next(),
7411            cmp::Ordering::Greater => self.excerpts.next(),
7412            cmp::Ordering::Equal => {
7413                self.diff_transforms.next();
7414                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7415                    || self.diff_transforms.item().is_none()
7416                {
7417                    self.excerpts.next();
7418                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7419                    self.diff_transforms.item()
7420                    && self
7421                        .excerpts
7422                        .item()
7423                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7424                {
7425                    self.excerpts.next();
7426                }
7427            }
7428        }
7429    }
7430
7431    fn prev(&mut self) {
7432        self.cached_region.take();
7433        match self
7434            .diff_transforms
7435            .start()
7436            .excerpt_dimension
7437            .cmp(self.excerpts.start())
7438        {
7439            cmp::Ordering::Less => self.excerpts.prev(),
7440            cmp::Ordering::Greater => self.diff_transforms.prev(),
7441            cmp::Ordering::Equal => {
7442                self.diff_transforms.prev();
7443                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7444                    || self.diff_transforms.item().is_none()
7445                {
7446                    self.excerpts.prev();
7447                }
7448            }
7449        }
7450    }
7451
7452    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7453        self.cached_region
7454            .get_or_init(|| self.build_region())
7455            .as_ref()
7456    }
7457
7458    fn is_at_start_of_excerpt(&mut self) -> bool {
7459        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7460            return false;
7461        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7462            return true;
7463        }
7464
7465        self.diff_transforms.prev();
7466        let prev_transform = self.diff_transforms.item();
7467        self.diff_transforms.next();
7468
7469        prev_transform.is_none_or(|next_transform| {
7470            matches!(next_transform, DiffTransform::BufferContent { .. })
7471        })
7472    }
7473
7474    fn is_at_end_of_excerpt(&self) -> bool {
7475        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7476            return false;
7477        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7478            || self.diff_transforms.item().is_none()
7479        {
7480            return true;
7481        }
7482
7483        let next_transform = self.diff_transforms.next_item();
7484        next_transform.is_none_or(|next_transform| match next_transform {
7485            DiffTransform::BufferContent { .. } => true,
7486            DiffTransform::DeletedHunk { hunk_info, .. } => self
7487                .excerpts
7488                .item()
7489                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7490        })
7491    }
7492
7493    fn main_buffer_position(&self) -> Option<BD> {
7494        let excerpt = self.excerpts.item()?;
7495        let buffer = &excerpt.buffer;
7496        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7497        let mut buffer_start = buffer_context_start;
7498        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7499        buffer_start += overshoot;
7500        Some(buffer_start)
7501    }
7502
7503    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7504        let excerpt = self.excerpts.item()?;
7505        match self.diff_transforms.item()? {
7506            DiffTransform::DeletedHunk {
7507                buffer_id,
7508                base_text_byte_range,
7509                has_trailing_newline,
7510                hunk_info,
7511                ..
7512            } => {
7513                let diff = self.diffs.get(buffer_id)?;
7514                let buffer = diff.base_text();
7515                let mut rope_cursor = buffer.as_rope().cursor(0);
7516                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7517                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7518                let mut buffer_end = buffer_start;
7519                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7520                let start = self.diff_transforms.start().output_dimension.0;
7521                let end = self.diff_transforms.end().output_dimension.0;
7522                Some(MultiBufferRegion {
7523                    buffer,
7524                    excerpt,
7525                    has_trailing_newline: *has_trailing_newline,
7526                    is_main_buffer: false,
7527                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7528                        hunk_info.hunk_secondary_status,
7529                    )),
7530                    buffer_range: buffer_start..buffer_end,
7531                    range: start..end,
7532                })
7533            }
7534            DiffTransform::BufferContent {
7535                inserted_hunk_info, ..
7536            } => {
7537                let buffer = &excerpt.buffer;
7538                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7539
7540                let mut start = self.diff_transforms.start().output_dimension.0;
7541                let mut buffer_start = buffer_context_start;
7542                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7543                    let overshoot =
7544                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7545                    start += overshoot;
7546                } else {
7547                    let overshoot =
7548                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7549                    buffer_start += overshoot;
7550                }
7551
7552                let mut end;
7553                let mut buffer_end;
7554                let has_trailing_newline;
7555                let transform_end = self.diff_transforms.end();
7556                if transform_end.excerpt_dimension < self.excerpts.end() {
7557                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7558                    end = transform_end.output_dimension.0;
7559                    buffer_end = buffer_context_start;
7560                    buffer_end += overshoot;
7561                    has_trailing_newline = false;
7562                } else {
7563                    let overshoot =
7564                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7565                    end = self.diff_transforms.start().output_dimension.0;
7566                    end += overshoot;
7567                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7568                    has_trailing_newline = excerpt.has_trailing_newline;
7569                };
7570
7571                let diff_hunk_status = inserted_hunk_info.map(|info| {
7572                    if info.is_logically_deleted {
7573                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7574                    } else {
7575                        DiffHunkStatus::added(info.hunk_secondary_status)
7576                    }
7577                });
7578
7579                Some(MultiBufferRegion {
7580                    buffer,
7581                    excerpt,
7582                    has_trailing_newline,
7583                    is_main_buffer: true,
7584                    diff_hunk_status,
7585                    buffer_range: buffer_start..buffer_end,
7586                    range: start..end,
7587                })
7588            }
7589        }
7590    }
7591
7592    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7593        let excerpt = self.excerpts.item()?;
7594        match self.diff_transforms.item()? {
7595            &DiffTransform::DeletedHunk { .. } => {
7596                let start = self.diff_transforms.start().output_dimension.0;
7597                let end = self.diff_transforms.end().output_dimension.0;
7598                Some((excerpt, start..end))
7599            }
7600            DiffTransform::BufferContent { .. } => {
7601                let mut start = self.diff_transforms.start().output_dimension.0;
7602                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7603                    let overshoot =
7604                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7605                    start += overshoot;
7606                }
7607
7608                let mut end;
7609                let transform_end = self.diff_transforms.end();
7610                if transform_end.excerpt_dimension < self.excerpts.end() {
7611                    end = transform_end.output_dimension.0;
7612                } else {
7613                    let overshoot =
7614                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7615                    end = self.diff_transforms.start().output_dimension.0;
7616                    end += overshoot;
7617                };
7618
7619                Some((excerpt, start..end))
7620            }
7621        }
7622    }
7623
7624    fn excerpt(&self) -> Option<&'a Excerpt> {
7625        self.excerpts.item()
7626    }
7627}
7628
7629impl Excerpt {
7630    fn new(
7631        id: ExcerptId,
7632        locator: Locator,
7633        buffer_id: BufferId,
7634        buffer: Arc<BufferSnapshot>,
7635        range: ExcerptRange<text::Anchor>,
7636        has_trailing_newline: bool,
7637    ) -> Self {
7638        Excerpt {
7639            id,
7640            locator,
7641            max_buffer_row: range.context.end.to_point(&buffer).row,
7642            text_summary: buffer
7643                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7644            buffer_id,
7645            buffer,
7646            range,
7647            has_trailing_newline,
7648        }
7649    }
7650
7651    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7652        let content_start = self.range.context.start.to_offset(&self.buffer);
7653        let chunks_start = content_start + range.start;
7654        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7655
7656        let has_footer = self.has_trailing_newline
7657            && range.start <= self.text_summary.len
7658            && range.end > self.text_summary.len;
7659
7660        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7661
7662        ExcerptChunks {
7663            excerpt_id: self.id,
7664            content_chunks,
7665            has_footer,
7666        }
7667    }
7668
7669    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7670        let content_start = self.range.context.start.to_offset(&self.buffer);
7671        let chunks_start = content_start + range.start;
7672        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7673        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7674        excerpt_chunks.has_footer = self.has_trailing_newline
7675            && range.start <= self.text_summary.len
7676            && range.end > self.text_summary.len;
7677    }
7678
7679    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7680        if text_anchor
7681            .cmp(&self.range.context.start, &self.buffer)
7682            .is_lt()
7683        {
7684            self.range.context.start
7685        } else if text_anchor
7686            .cmp(&self.range.context.end, &self.buffer)
7687            .is_gt()
7688        {
7689            self.range.context.end
7690        } else {
7691            text_anchor
7692        }
7693    }
7694
7695    fn contains(&self, anchor: &Anchor) -> bool {
7696        (anchor.text_anchor.buffer_id == None
7697            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7698            && self
7699                .range
7700                .context
7701                .start
7702                .cmp(&anchor.text_anchor, &self.buffer)
7703                .is_le()
7704            && self
7705                .range
7706                .context
7707                .end
7708                .cmp(&anchor.text_anchor, &self.buffer)
7709                .is_ge()
7710    }
7711
7712    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7713    fn buffer_start_offset(&self) -> BufferOffset {
7714        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7715    }
7716
7717    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7718    fn buffer_end_offset(&self) -> BufferOffset {
7719        self.buffer_start_offset() + self.text_summary.len
7720    }
7721}
7722
7723impl<'a> MultiBufferExcerpt<'a> {
7724    pub fn id(&self) -> ExcerptId {
7725        self.excerpt.id
7726    }
7727
7728    pub fn buffer_id(&self) -> BufferId {
7729        self.excerpt.buffer_id
7730    }
7731
7732    pub fn start_anchor(&self) -> Anchor {
7733        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7734    }
7735
7736    pub fn end_anchor(&self) -> Anchor {
7737        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7738    }
7739
7740    pub fn buffer(&self) -> &'a BufferSnapshot {
7741        &self.excerpt.buffer
7742    }
7743
7744    pub fn buffer_range(&self) -> Range<BufferOffset> {
7745        self.buffer_offset
7746            ..BufferOffset(
7747                self.excerpt
7748                    .range
7749                    .context
7750                    .end
7751                    .to_offset(&self.excerpt.buffer.text),
7752            )
7753    }
7754
7755    pub fn start_offset(&self) -> MultiBufferOffset {
7756        self.offset
7757    }
7758
7759    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7760    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7761        self.map_range_to_buffer(offset..offset).start
7762    }
7763
7764    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7765    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7766        self.diff_transforms
7767            .seek(&OutputDimension(range.start), Bias::Right);
7768        let start = self.map_offset_to_buffer_internal(range.start);
7769        let end = if range.end > range.start {
7770            self.diff_transforms
7771                .seek_forward(&OutputDimension(range.end), Bias::Right);
7772            self.map_offset_to_buffer_internal(range.end)
7773        } else {
7774            start
7775        };
7776        start..end
7777    }
7778
7779    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7780        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7781        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7782            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7783        };
7784        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7785        self.buffer_offset + offset_in_excerpt
7786    }
7787
7788    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7789    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7790        self.map_range_from_buffer(buffer_offset..buffer_offset)
7791            .start
7792    }
7793
7794    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7795    pub fn map_range_from_buffer(
7796        &mut self,
7797        buffer_range: Range<BufferOffset>,
7798    ) -> Range<MultiBufferOffset> {
7799        if buffer_range.start < self.buffer_offset {
7800            log::warn!(
7801                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7802            );
7803            return self.offset..self.offset;
7804        }
7805        let overshoot = buffer_range.start - self.buffer_offset;
7806        let excerpt_offset = self.excerpt_offset + overshoot;
7807        let excerpt_seek_dim = excerpt_offset;
7808        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7809        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7810            log::warn!(
7811                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7812            );
7813            return self.offset..self.offset;
7814        }
7815        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7816        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7817
7818        let end = if buffer_range.start < buffer_range.end {
7819            let overshoot = buffer_range.end - self.buffer_offset;
7820            let excerpt_offset = self.excerpt_offset + overshoot;
7821            let excerpt_seek_dim = excerpt_offset;
7822            self.diff_transforms
7823                .seek_forward(&excerpt_seek_dim, Bias::Right);
7824            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7825            // todo(lw): Clamp end to the excerpt boundaries
7826            self.diff_transforms.start().output_dimension.0 + overshoot
7827        } else {
7828            start
7829        };
7830
7831        start..end
7832    }
7833
7834    /// Returns true if the entirety of the given range is in the buffer's excerpt
7835    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7836        range.start >= self.excerpt.buffer_start_offset()
7837            && range.end <= self.excerpt.buffer_end_offset()
7838    }
7839
7840    /// Returns true if any part of the given range is in the buffer's excerpt
7841    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7842        range.start <= self.excerpt.buffer_end_offset()
7843            && range.end >= self.excerpt.buffer_start_offset()
7844    }
7845
7846    pub fn max_buffer_row(&self) -> u32 {
7847        self.excerpt.max_buffer_row
7848    }
7849}
7850
7851impl ExcerptId {
7852    pub fn min() -> Self {
7853        Self(0)
7854    }
7855
7856    pub fn max() -> Self {
7857        Self(u32::MAX)
7858    }
7859
7860    pub fn to_proto(self) -> u64 {
7861        self.0 as _
7862    }
7863
7864    pub fn from_proto(proto: u64) -> Self {
7865        Self(proto as _)
7866    }
7867
7868    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7869        let a = snapshot.excerpt_locator_for_id(*self);
7870        let b = snapshot.excerpt_locator_for_id(*other);
7871        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7872    }
7873}
7874
7875impl From<ExcerptId> for usize {
7876    fn from(val: ExcerptId) -> Self {
7877        val.0 as usize
7878    }
7879}
7880
7881impl fmt::Debug for Excerpt {
7882    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7883        f.debug_struct("Excerpt")
7884            .field("id", &self.id)
7885            .field("locator", &self.locator)
7886            .field("buffer_id", &self.buffer_id)
7887            .field("range", &self.range)
7888            .field("text_summary", &self.text_summary)
7889            .field("has_trailing_newline", &self.has_trailing_newline)
7890            .finish()
7891    }
7892}
7893
7894impl sum_tree::Item for Excerpt {
7895    type Summary = ExcerptSummary;
7896
7897    fn summary(&self, _cx: ()) -> Self::Summary {
7898        let mut text = self.text_summary;
7899        if self.has_trailing_newline {
7900            text += TextSummary::from("\n");
7901        }
7902        ExcerptSummary {
7903            excerpt_id: self.id,
7904            excerpt_locator: self.locator.clone(),
7905            widest_line_number: self.max_buffer_row,
7906            text: text.into(),
7907            count: 1,
7908        }
7909    }
7910}
7911
7912impl sum_tree::Item for ExcerptIdMapping {
7913    type Summary = ExcerptId;
7914
7915    fn summary(&self, _cx: ()) -> Self::Summary {
7916        self.id
7917    }
7918}
7919
7920impl sum_tree::KeyedItem for ExcerptIdMapping {
7921    type Key = ExcerptId;
7922
7923    fn key(&self) -> Self::Key {
7924        self.id
7925    }
7926}
7927
7928impl DiffTransform {
7929    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7930        match self {
7931            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7932            DiffTransform::BufferContent {
7933                inserted_hunk_info, ..
7934            } => *inserted_hunk_info,
7935        }
7936    }
7937}
7938
7939impl sum_tree::Item for DiffTransform {
7940    type Summary = DiffTransformSummary;
7941
7942    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7943        match self {
7944            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7945                input: *summary,
7946                output: *summary,
7947            },
7948            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7949                input: MBTextSummary::default(),
7950                output: summary.into(),
7951            },
7952        }
7953    }
7954}
7955
7956impl DiffTransformSummary {
7957    fn excerpt_len(&self) -> ExcerptOffset {
7958        ExcerptDimension(self.input.len)
7959    }
7960}
7961
7962impl sum_tree::ContextLessSummary for DiffTransformSummary {
7963    fn zero() -> Self {
7964        DiffTransformSummary {
7965            input: MBTextSummary::default(),
7966            output: MBTextSummary::default(),
7967        }
7968    }
7969
7970    fn add_summary(&mut self, other: &Self) {
7971        self.input += other.input;
7972        self.output += other.output;
7973    }
7974}
7975
7976impl sum_tree::ContextLessSummary for ExcerptId {
7977    fn zero() -> Self {
7978        Self(0)
7979    }
7980
7981    fn add_summary(&mut self, summary: &Self) {
7982        *self = cmp::max(*self, *summary);
7983    }
7984}
7985
7986impl sum_tree::ContextLessSummary for ExcerptSummary {
7987    fn zero() -> Self {
7988        Self::default()
7989    }
7990
7991    fn add_summary(&mut self, summary: &Self) {
7992        debug_assert!(
7993            summary.excerpt_locator > self.excerpt_locator
7994                || self.excerpt_locator == Locator::min(),
7995            "Excerpt locators must be in ascending order: {:?} > {:?}",
7996            summary.excerpt_locator,
7997            self.excerpt_locator
7998        );
7999        self.excerpt_locator = summary.excerpt_locator.clone();
8000        self.text += summary.text;
8001        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
8002        self.count += summary.count;
8003    }
8004}
8005
8006impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8007    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8008        Ord::cmp(&Some(self), cursor_location)
8009    }
8010}
8011
8012impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8013    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8014        Ord::cmp(self, &cursor_location.excerpt_locator)
8015    }
8016}
8017
8018impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8019where
8020    MBD: MultiBufferDimension + Default,
8021{
8022    fn zero(_: ()) -> Self {
8023        ExcerptDimension(MBD::default())
8024    }
8025
8026    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8027        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8028    }
8029}
8030
8031impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8032    fn zero(_cx: ()) -> Self {
8033        Default::default()
8034    }
8035
8036    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8037        *self = Some(&summary.excerpt_locator);
8038    }
8039}
8040
8041impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8042    fn zero(_cx: ()) -> Self {
8043        Default::default()
8044    }
8045
8046    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8047        *self = Some(summary.excerpt_id);
8048    }
8049}
8050
8051#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8052struct OutputDimension<T>(T);
8053
8054impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8055    fn eq(&self, other: &T) -> bool {
8056        self.0 == *other
8057    }
8058}
8059
8060impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8061    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8062        self.0.partial_cmp(other)
8063    }
8064}
8065
8066impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8067where
8068    T: ops::Sub<U, Output = R>,
8069{
8070    type Output = R;
8071
8072    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8073        self.0 - other.0
8074    }
8075}
8076
8077impl<R, T, U> ops::Add<U> for OutputDimension<T>
8078where
8079    T: ops::Add<U, Output = R>,
8080{
8081    type Output = OutputDimension<R>;
8082
8083    fn add(self, other: U) -> Self::Output {
8084        OutputDimension(self.0 + other)
8085    }
8086}
8087
8088impl<T, U> AddAssign<U> for OutputDimension<T>
8089where
8090    T: AddAssign<U>,
8091{
8092    fn add_assign(&mut self, other: U) {
8093        self.0 += other;
8094    }
8095}
8096
8097impl<T, U> SubAssign<U> for OutputDimension<T>
8098where
8099    T: SubAssign<U>,
8100{
8101    fn sub_assign(&mut self, other: U) {
8102        self.0 -= other;
8103    }
8104}
8105
8106#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8107struct ExcerptDimension<T>(T);
8108
8109impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8110    fn eq(&self, other: &T) -> bool {
8111        self.0 == *other
8112    }
8113}
8114
8115impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8116    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8117        self.0.partial_cmp(other)
8118    }
8119}
8120
8121impl ExcerptOffset {
8122    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8123        self.0.saturating_sub(other.0)
8124    }
8125}
8126
8127impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8128where
8129    T: ops::Sub<U, Output = R>,
8130{
8131    type Output = R;
8132
8133    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8134        self.0 - other.0
8135    }
8136}
8137
8138impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8139where
8140    T: ops::Add<U, Output = R>,
8141{
8142    type Output = ExcerptDimension<R>;
8143
8144    fn add(self, other: U) -> Self::Output {
8145        ExcerptDimension(self.0 + other)
8146    }
8147}
8148
8149impl<T, U> AddAssign<U> for ExcerptDimension<T>
8150where
8151    T: AddAssign<U>,
8152{
8153    fn add_assign(&mut self, other: U) {
8154        self.0 += other;
8155    }
8156}
8157
8158impl<T, U> SubAssign<U> for ExcerptDimension<T>
8159where
8160    T: SubAssign<U>,
8161{
8162    fn sub_assign(&mut self, other: U) {
8163        self.0 -= other;
8164    }
8165}
8166
8167impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8168    fn zero(_: ()) -> Self {
8169        MultiBufferOffset::ZERO
8170    }
8171
8172    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8173        *self += summary.output.len;
8174    }
8175}
8176
8177impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8178    for ExcerptDimension<MBD>
8179where
8180    MBD: MultiBufferDimension + Ord,
8181{
8182    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8183        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8184    }
8185}
8186
8187impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8188    for ExcerptDimension<MBD>
8189where
8190    MBD: MultiBufferDimension + Ord,
8191{
8192    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8193        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8194    }
8195}
8196
8197impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8198    for ExcerptDimension<MBD>
8199{
8200    fn zero(_: ()) -> Self {
8201        ExcerptDimension(MBD::default())
8202    }
8203
8204    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8205        self.0.add_mb_text_summary(&summary.input)
8206    }
8207}
8208
8209impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8210    for OutputDimension<MBD>
8211where
8212    MBD: MultiBufferDimension + Ord,
8213{
8214    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8215        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8216    }
8217}
8218
8219impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8220    for OutputDimension<MBD>
8221{
8222    fn zero(_: ()) -> Self {
8223        OutputDimension(MBD::default())
8224    }
8225
8226    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8227        self.0.add_mb_text_summary(&summary.output)
8228    }
8229}
8230
8231impl MultiBufferRows<'_> {
8232    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8233        self.point = Point::new(row, 0);
8234        self.cursor.seek(&self.point);
8235    }
8236}
8237
8238impl Iterator for MultiBufferRows<'_> {
8239    type Item = RowInfo;
8240
8241    fn next(&mut self) -> Option<Self::Item> {
8242        if self.is_empty && self.point.row == 0 {
8243            self.point += Point::new(1, 0);
8244            return Some(RowInfo {
8245                buffer_id: None,
8246                buffer_row: Some(0),
8247                multibuffer_row: Some(MultiBufferRow(0)),
8248                diff_status: None,
8249                expand_info: None,
8250                wrapped_buffer_row: None,
8251            });
8252        }
8253
8254        let mut region = self.cursor.region()?.clone();
8255        while self.point >= region.range.end {
8256            self.cursor.next();
8257            if let Some(next_region) = self.cursor.region() {
8258                region = next_region.clone();
8259            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8260                let multibuffer_row = MultiBufferRow(self.point.row);
8261                let last_excerpt = self
8262                    .cursor
8263                    .excerpts
8264                    .item()
8265                    .or(self.cursor.excerpts.prev_item())?;
8266                let last_row = last_excerpt
8267                    .range
8268                    .context
8269                    .end
8270                    .to_point(&last_excerpt.buffer)
8271                    .row;
8272
8273                let first_row = last_excerpt
8274                    .range
8275                    .context
8276                    .start
8277                    .to_point(&last_excerpt.buffer)
8278                    .row;
8279
8280                let expand_info = if self.is_singleton {
8281                    None
8282                } else {
8283                    let needs_expand_up = first_row == last_row
8284                        && last_row > 0
8285                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8286                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8287
8288                    if needs_expand_up && needs_expand_down {
8289                        Some(ExpandExcerptDirection::UpAndDown)
8290                    } else if needs_expand_up {
8291                        Some(ExpandExcerptDirection::Up)
8292                    } else if needs_expand_down {
8293                        Some(ExpandExcerptDirection::Down)
8294                    } else {
8295                        None
8296                    }
8297                    .map(|direction| ExpandInfo {
8298                        direction,
8299                        excerpt_id: last_excerpt.id,
8300                    })
8301                };
8302                self.point += Point::new(1, 0);
8303                return Some(RowInfo {
8304                    buffer_id: Some(last_excerpt.buffer_id),
8305                    buffer_row: Some(last_row),
8306                    multibuffer_row: Some(multibuffer_row),
8307                    diff_status: None,
8308                    wrapped_buffer_row: None,
8309                    expand_info,
8310                });
8311            } else {
8312                return None;
8313            };
8314        }
8315
8316        let overshoot = self.point - region.range.start;
8317        let buffer_point = region.buffer_range.start + overshoot;
8318        let expand_info = if self.is_singleton {
8319            None
8320        } else {
8321            let needs_expand_up = self.point.row == region.range.start.row
8322                && self.cursor.is_at_start_of_excerpt()
8323                && buffer_point.row > 0;
8324            let needs_expand_down = (region.excerpt.has_trailing_newline
8325                && self.point.row + 1 == region.range.end.row
8326                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8327                && self.cursor.is_at_end_of_excerpt()
8328                && buffer_point.row < region.buffer.max_point().row;
8329
8330            if needs_expand_up && needs_expand_down {
8331                Some(ExpandExcerptDirection::UpAndDown)
8332            } else if needs_expand_up {
8333                Some(ExpandExcerptDirection::Up)
8334            } else if needs_expand_down {
8335                Some(ExpandExcerptDirection::Down)
8336            } else {
8337                None
8338            }
8339            .map(|direction| ExpandInfo {
8340                direction,
8341                excerpt_id: region.excerpt.id,
8342            })
8343        };
8344
8345        let result = Some(RowInfo {
8346            buffer_id: Some(region.buffer.remote_id()),
8347            buffer_row: Some(buffer_point.row),
8348            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8349            diff_status: region
8350                .diff_hunk_status
8351                .filter(|_| self.point < region.range.end),
8352            expand_info,
8353            wrapped_buffer_row: None,
8354        });
8355        self.point += Point::new(1, 0);
8356        result
8357    }
8358}
8359
8360impl<'a> MultiBufferChunks<'a> {
8361    pub fn offset(&self) -> MultiBufferOffset {
8362        self.range.start
8363    }
8364
8365    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8366        self.diff_transforms.seek(&range.end, Bias::Right);
8367        let mut excerpt_end = self.diff_transforms.start().1;
8368        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8369            let overshoot = range.end - self.diff_transforms.start().0;
8370            excerpt_end += overshoot;
8371        }
8372
8373        self.diff_transforms.seek(&range.start, Bias::Right);
8374        let mut excerpt_start = self.diff_transforms.start().1;
8375        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8376            let overshoot = range.start - self.diff_transforms.start().0;
8377            excerpt_start += overshoot;
8378        }
8379
8380        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8381        self.buffer_chunk.take();
8382        self.range = range;
8383    }
8384
8385    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8386        self.excerpt_offset_range = new_range.clone();
8387        self.excerpts.seek(&new_range.start, Bias::Right);
8388        if let Some(excerpt) = self.excerpts.item() {
8389            let excerpt_start = *self.excerpts.start();
8390            if let Some(excerpt_chunks) = self
8391                .excerpt_chunks
8392                .as_mut()
8393                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8394            {
8395                excerpt.seek_chunks(
8396                    excerpt_chunks,
8397                    (self.excerpt_offset_range.start - excerpt_start)
8398                        ..(self.excerpt_offset_range.end - excerpt_start),
8399                );
8400            } else {
8401                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8402                    (self.excerpt_offset_range.start - excerpt_start)
8403                        ..(self.excerpt_offset_range.end - excerpt_start),
8404                    self.language_aware,
8405                ));
8406            }
8407        } else {
8408            self.excerpt_chunks = None;
8409        }
8410    }
8411
8412    #[ztracing::instrument(skip_all)]
8413    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8414        loop {
8415            if self.excerpt_offset_range.is_empty() {
8416                return None;
8417            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8418                self.excerpt_offset_range.start += chunk.text.len();
8419                return Some(chunk);
8420            } else {
8421                self.excerpts.next();
8422                let excerpt = self.excerpts.item()?;
8423                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8424                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8425                    self.language_aware,
8426                ));
8427            }
8428        }
8429    }
8430}
8431
8432impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8433    type Item = &'a str;
8434
8435    fn next(&mut self) -> Option<Self::Item> {
8436        let mut region = self.cursor.region()?;
8437        if self.offset == region.range.start {
8438            self.cursor.prev();
8439            region = self.cursor.region()?;
8440            let start_overshoot = self.start.saturating_sub(region.range.start);
8441            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8442                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8443            ));
8444        }
8445
8446        if self.offset == region.range.end && region.has_trailing_newline {
8447            self.offset -= 1;
8448            Some("\n")
8449        } else {
8450            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8451            self.offset -= chunk.len();
8452            Some(chunk)
8453        }
8454    }
8455}
8456
8457impl<'a> Iterator for MultiBufferChunks<'a> {
8458    type Item = Chunk<'a>;
8459
8460    #[ztracing::instrument(skip_all)]
8461    fn next(&mut self) -> Option<Chunk<'a>> {
8462        if self.range.start >= self.range.end {
8463            return None;
8464        }
8465        if self.range.start == self.diff_transforms.end().0 {
8466            self.diff_transforms.next();
8467        }
8468
8469        let diff_transform_start = self.diff_transforms.start().0;
8470        let diff_transform_end = self.diff_transforms.end().0;
8471        debug_assert!(
8472            self.range.start < diff_transform_end,
8473            "{:?} < {:?} of ({1:?}..{2:?})",
8474            self.range.start,
8475            diff_transform_end,
8476            diff_transform_start
8477        );
8478
8479        let diff_transform = self.diff_transforms.item()?;
8480        match diff_transform {
8481            DiffTransform::BufferContent { .. } => {
8482                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8483                    chunk
8484                } else {
8485                    let chunk = self.next_excerpt_chunk().unwrap();
8486                    self.buffer_chunk.insert(chunk)
8487                };
8488
8489                let chunk_end = self.range.start + chunk.text.len();
8490                let diff_transform_end = diff_transform_end.min(self.range.end);
8491
8492                if diff_transform_end < chunk_end {
8493                    let split_idx = diff_transform_end - self.range.start;
8494                    let (before, after) = chunk.text.split_at(split_idx);
8495                    self.range.start = diff_transform_end;
8496                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8497                    let chars = chunk.chars & mask;
8498                    let tabs = chunk.tabs & mask;
8499                    let newlines = chunk.newlines & mask;
8500
8501                    chunk.text = after;
8502                    chunk.chars = chunk.chars >> split_idx;
8503                    chunk.tabs = chunk.tabs >> split_idx;
8504                    chunk.newlines = chunk.newlines >> split_idx;
8505
8506                    Some(Chunk {
8507                        text: before,
8508                        chars,
8509                        tabs,
8510                        newlines,
8511                        ..chunk.clone()
8512                    })
8513                } else {
8514                    self.range.start = chunk_end;
8515                    self.buffer_chunk.take()
8516                }
8517            }
8518            DiffTransform::DeletedHunk {
8519                buffer_id,
8520                base_text_byte_range,
8521                has_trailing_newline,
8522                ..
8523            } => {
8524                let base_text_start =
8525                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8526                let base_text_end =
8527                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8528                let base_text_end = base_text_end.min(base_text_byte_range.end);
8529
8530                let mut chunks = if let Some((_, mut chunks)) = self
8531                    .diff_base_chunks
8532                    .take()
8533                    .filter(|(id, _)| id == buffer_id)
8534                {
8535                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8536                    {
8537                        chunks.seek(base_text_start..base_text_end);
8538                    }
8539                    chunks
8540                } else {
8541                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8542                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8543                };
8544
8545                let chunk = if let Some(chunk) = chunks.next() {
8546                    self.range.start += chunk.text.len();
8547                    self.diff_base_chunks = Some((*buffer_id, chunks));
8548                    chunk
8549                } else {
8550                    debug_assert!(has_trailing_newline);
8551                    self.range.start += "\n".len();
8552                    Chunk {
8553                        text: "\n",
8554                        chars: 1u128,
8555                        newlines: 1u128,
8556                        ..Default::default()
8557                    }
8558                };
8559                Some(chunk)
8560            }
8561        }
8562    }
8563}
8564
8565impl MultiBufferBytes<'_> {
8566    fn consume(&mut self, len: usize) {
8567        self.range.start += len;
8568        self.chunk = &self.chunk[len..];
8569
8570        if !self.range.is_empty() && self.chunk.is_empty() {
8571            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8572                self.chunk = chunk;
8573            } else if self.has_trailing_newline {
8574                self.has_trailing_newline = false;
8575                self.chunk = b"\n";
8576            } else {
8577                self.cursor.next();
8578                if let Some(region) = self.cursor.region() {
8579                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8580                        region.buffer_range.start
8581                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8582                                .min(region.buffer_range.end),
8583                    );
8584                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8585                    self.excerpt_bytes = Some(excerpt_bytes);
8586                    self.has_trailing_newline =
8587                        region.has_trailing_newline && self.range.end >= region.range.end;
8588                    if self.chunk.is_empty() && self.has_trailing_newline {
8589                        self.has_trailing_newline = false;
8590                        self.chunk = b"\n";
8591                    }
8592                }
8593            }
8594        }
8595    }
8596}
8597
8598impl<'a> Iterator for MultiBufferBytes<'a> {
8599    type Item = &'a [u8];
8600
8601    fn next(&mut self) -> Option<Self::Item> {
8602        let chunk = self.chunk;
8603        if chunk.is_empty() {
8604            None
8605        } else {
8606            self.consume(chunk.len());
8607            Some(chunk)
8608        }
8609    }
8610}
8611
8612impl io::Read for MultiBufferBytes<'_> {
8613    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8614        let len = cmp::min(buf.len(), self.chunk.len());
8615        buf[..len].copy_from_slice(&self.chunk[..len]);
8616        if len > 0 {
8617            self.consume(len);
8618        }
8619        Ok(len)
8620    }
8621}
8622
8623impl io::Read for ReversedMultiBufferBytes<'_> {
8624    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8625        let len = cmp::min(buf.len(), self.chunk.len());
8626        buf[..len].copy_from_slice(&self.chunk[..len]);
8627        buf[..len].reverse();
8628        if len > 0 {
8629            self.range.end -= len;
8630            self.chunk = &self.chunk[..self.chunk.len() - len];
8631            if !self.range.is_empty()
8632                && self.chunk.is_empty()
8633                && let Some(chunk) = self.chunks.next()
8634            {
8635                self.chunk = chunk.as_bytes();
8636            }
8637        }
8638        Ok(len)
8639    }
8640}
8641
8642impl<'a> Iterator for ExcerptChunks<'a> {
8643    type Item = Chunk<'a>;
8644
8645    fn next(&mut self) -> Option<Self::Item> {
8646        if let Some(chunk) = self.content_chunks.next() {
8647            return Some(chunk);
8648        }
8649
8650        if self.has_footer {
8651            let text = "\n";
8652            let chars = 0b1;
8653            let newlines = 0b1;
8654            self.has_footer = false;
8655            return Some(Chunk {
8656                text,
8657                chars,
8658                newlines,
8659                ..Default::default()
8660            });
8661        }
8662
8663        None
8664    }
8665}
8666
8667impl ToOffset for Point {
8668    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8669        snapshot.point_to_offset(*self)
8670    }
8671    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8672        snapshot.point_to_offset_utf16(*self)
8673    }
8674}
8675
8676impl ToOffset for MultiBufferOffset {
8677    #[track_caller]
8678    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8679        assert!(
8680            *self <= snapshot.len(),
8681            "offset {} is greater than the snapshot.len() {}",
8682            self.0,
8683            snapshot.len().0,
8684        );
8685        *self
8686    }
8687    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8688        snapshot.offset_to_offset_utf16(*self)
8689    }
8690}
8691
8692impl ToOffset for MultiBufferOffsetUtf16 {
8693    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8694        snapshot.offset_utf16_to_offset(*self)
8695    }
8696
8697    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8698        *self
8699    }
8700}
8701
8702impl ToOffset for PointUtf16 {
8703    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8704        snapshot.point_utf16_to_offset(*self)
8705    }
8706    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8707        snapshot.point_utf16_to_offset_utf16(*self)
8708    }
8709}
8710
8711impl ToPoint for MultiBufferOffset {
8712    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8713        snapshot.offset_to_point(*self)
8714    }
8715    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8716        snapshot.offset_to_point_utf16(*self)
8717    }
8718}
8719
8720impl ToPoint for Point {
8721    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8722        *self
8723    }
8724    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8725        snapshot.point_to_point_utf16(*self)
8726    }
8727}
8728
8729impl ToPoint for PointUtf16 {
8730    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8731        snapshot.point_utf16_to_point(*self)
8732    }
8733    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8734        *self
8735    }
8736}
8737
8738impl From<ExcerptId> for EntityId {
8739    fn from(id: ExcerptId) -> Self {
8740        EntityId::from(id.0 as u64)
8741    }
8742}
8743
8744#[cfg(debug_assertions)]
8745pub mod debug {
8746    use super::*;
8747
8748    pub trait ToMultiBufferDebugRanges {
8749        fn to_multi_buffer_debug_ranges(
8750            &self,
8751            snapshot: &MultiBufferSnapshot,
8752        ) -> Vec<Range<MultiBufferOffset>>;
8753    }
8754
8755    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8756        fn to_multi_buffer_debug_ranges(
8757            &self,
8758            snapshot: &MultiBufferSnapshot,
8759        ) -> Vec<Range<MultiBufferOffset>> {
8760            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8761        }
8762    }
8763
8764    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8765        fn to_multi_buffer_debug_ranges(
8766            &self,
8767            snapshot: &MultiBufferSnapshot,
8768        ) -> Vec<Range<MultiBufferOffset>> {
8769            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8770                .to_multi_buffer_debug_ranges(snapshot)
8771        }
8772    }
8773
8774    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8775        fn to_multi_buffer_debug_ranges(
8776            &self,
8777            snapshot: &MultiBufferSnapshot,
8778        ) -> Vec<Range<MultiBufferOffset>> {
8779            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8780        }
8781    }
8782
8783    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8784        fn to_multi_buffer_debug_ranges(
8785            &self,
8786            snapshot: &MultiBufferSnapshot,
8787        ) -> Vec<Range<MultiBufferOffset>> {
8788            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8789        }
8790    }
8791
8792    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8793        fn to_multi_buffer_debug_ranges(
8794            &self,
8795            snapshot: &MultiBufferSnapshot,
8796        ) -> Vec<Range<MultiBufferOffset>> {
8797            self.iter()
8798                .map(|item| {
8799                    let offset = item.to_offset(snapshot);
8800                    offset..offset
8801                })
8802                .collect()
8803        }
8804    }
8805
8806    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8807        fn to_multi_buffer_debug_ranges(
8808            &self,
8809            snapshot: &MultiBufferSnapshot,
8810        ) -> Vec<Range<MultiBufferOffset>> {
8811            self.iter()
8812                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8813                .collect()
8814        }
8815    }
8816}