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::{AllLanguageSettings, LanguageSettings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use settings::Settings;
  34use smallvec::SmallVec;
  35use smol::future::yield_now;
  36use std::{
  37    any::type_name,
  38    borrow::Cow,
  39    cell::{Cell, OnceCell, Ref, RefCell},
  40    cmp, fmt,
  41    future::Future,
  42    io,
  43    iter::{self, FromIterator},
  44    mem,
  45    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  46    rc::Rc,
  47    str,
  48    sync::{Arc, OnceLock},
  49    time::Duration,
  50};
  51use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  52use text::{
  53    BufferId, Edit, LineIndent, TextSummary,
  54    locator::Locator,
  55    subscription::{Subscription, Topic},
  56};
  57use theme::SyntaxTheme;
  58use util::post_inc;
  59use ztracing::instrument;
  60
  61pub use self::path_key::{PathExcerptInsertResult, PathKey};
  62
  63pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  64
  65pub fn excerpt_context_lines(cx: &App) -> u32 {
  66    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  67}
  68
  69#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  70pub struct ExcerptId(u32);
  71
  72/// One or more [`Buffers`](Buffer) being edited in a single view.
  73///
  74/// See <https://zed.dev/features#multi-buffers>
  75pub struct MultiBuffer {
  76    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  77    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  78    snapshot: RefCell<MultiBufferSnapshot>,
  79    /// Contains the state of the buffers being edited
  80    buffers: BTreeMap<BufferId, BufferState>,
  81    /// Mapping from path keys to their excerpts.
  82    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  83    /// Mapping from excerpt IDs to their path key.
  84    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  85    /// Mapping from buffer IDs to their diff states
  86    diffs: HashMap<BufferId, DiffState>,
  87    subscriptions: Topic<MultiBufferOffset>,
  88    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  89    singleton: bool,
  90    /// The history of the multi-buffer.
  91    history: History,
  92    /// The explicit title of the multi-buffer.
  93    /// If `None`, it will be derived from the underlying path or content.
  94    title: Option<String>,
  95    /// The writing capability of the multi-buffer.
  96    capability: Capability,
  97    buffer_changed_since_sync: Rc<Cell<bool>>,
  98}
  99
 100#[derive(Clone, Debug, PartialEq, Eq)]
 101pub enum Event {
 102    ExcerptsAdded {
 103        buffer: Entity<Buffer>,
 104        predecessor: ExcerptId,
 105        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 106    },
 107    ExcerptsRemoved {
 108        ids: Vec<ExcerptId>,
 109        /// Contains only buffer IDs for which all excerpts have been removed.
 110        /// Buffers that still have remaining excerpts are never included.
 111        removed_buffer_ids: Vec<BufferId>,
 112    },
 113    ExcerptsExpanded {
 114        ids: Vec<ExcerptId>,
 115    },
 116    ExcerptsEdited {
 117        excerpt_ids: Vec<ExcerptId>,
 118        buffer_ids: Vec<BufferId>,
 119    },
 120    DiffHunksToggled,
 121    Edited {
 122        edited_buffer: Option<Entity<Buffer>>,
 123        is_local: bool,
 124    },
 125    TransactionUndone {
 126        transaction_id: TransactionId,
 127    },
 128    Reloaded,
 129    LanguageChanged(BufferId, bool),
 130    Reparsed(BufferId),
 131    Saved,
 132    FileHandleChanged,
 133    DirtyChanged,
 134    DiagnosticsUpdated,
 135    BufferDiffChanged,
 136}
 137
 138/// A diff hunk, representing a range of consequent lines in a multibuffer.
 139#[derive(Debug, Clone, PartialEq, Eq)]
 140pub struct MultiBufferDiffHunk {
 141    /// The row range in the multibuffer where this diff hunk appears.
 142    pub row_range: Range<MultiBufferRow>,
 143    /// The buffer ID that this hunk belongs to.
 144    pub buffer_id: BufferId,
 145    /// The range of the underlying buffer that this hunk corresponds to.
 146    pub buffer_range: Range<text::Anchor>,
 147    /// The excerpt that contains the diff hunk.
 148    pub excerpt_id: ExcerptId,
 149    /// The range within the buffer's diff base that this hunk corresponds to.
 150    pub diff_base_byte_range: Range<BufferOffset>,
 151    /// The status of this hunk (added/modified/deleted and secondary status).
 152    pub status: DiffHunkStatus,
 153    /// The word diffs for this hunk.
 154    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 155}
 156
 157impl MultiBufferDiffHunk {
 158    pub fn status(&self) -> DiffHunkStatus {
 159        self.status
 160    }
 161
 162    pub fn is_created_file(&self) -> bool {
 163        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 164            && self.buffer_range.start.is_min()
 165            && self.buffer_range.end.is_max()
 166    }
 167
 168    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 169        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 170        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 171        start..end
 172    }
 173}
 174
 175pub type MultiBufferPoint = Point;
 176type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 177type ExcerptPoint = ExcerptDimension<Point>;
 178
 179#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 180#[serde(transparent)]
 181pub struct MultiBufferRow(pub u32);
 182
 183impl MultiBufferRow {
 184    pub const MIN: Self = Self(0);
 185    pub const MAX: Self = Self(u32::MAX);
 186}
 187
 188impl ops::Add<usize> for MultiBufferRow {
 189    type Output = Self;
 190
 191    fn add(self, rhs: usize) -> Self::Output {
 192        MultiBufferRow(self.0 + rhs as u32)
 193    }
 194}
 195
 196pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 197    type TextDimension: TextDimension;
 198    fn from_summary(summary: &MBTextSummary) -> Self;
 199
 200    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 201
 202    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 203}
 204
 205// todo(lw): MultiBufferPoint
 206impl MultiBufferDimension for Point {
 207    type TextDimension = Point;
 208    fn from_summary(summary: &MBTextSummary) -> Self {
 209        summary.lines
 210    }
 211
 212    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 213        *self += *other;
 214    }
 215
 216    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 217        *self += summary.lines;
 218    }
 219}
 220
 221// todo(lw): MultiBufferPointUtf16
 222impl MultiBufferDimension for PointUtf16 {
 223    type TextDimension = PointUtf16;
 224    fn from_summary(summary: &MBTextSummary) -> Self {
 225        summary.lines_utf16()
 226    }
 227
 228    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 229        *self += *other;
 230    }
 231
 232    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 233        *self += summary.lines_utf16();
 234    }
 235}
 236
 237#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 238pub struct MultiBufferOffset(pub usize);
 239
 240impl fmt::Display for MultiBufferOffset {
 241    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 242        write!(f, "{}", self.0)
 243    }
 244}
 245
 246impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 247    type Sampler = MultiBufferOffsetUniformSampler;
 248}
 249
 250pub struct MultiBufferOffsetUniformSampler {
 251    sampler: rand::distr::uniform::UniformUsize,
 252}
 253
 254impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 255    type X = MultiBufferOffset;
 256
 257    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 258    where
 259        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 260        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 261    {
 262        let low = *low_b.borrow();
 263        let high = *high_b.borrow();
 264        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 265        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 266    }
 267
 268    #[inline] // if the range is constant, this helps LLVM to do the
 269    // calculations at compile-time.
 270    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 271    where
 272        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 273        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 274    {
 275        let low = *low_b.borrow();
 276        let high = *high_b.borrow();
 277        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 278        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 279    }
 280
 281    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 282        MultiBufferOffset(self.sampler.sample(rng))
 283    }
 284}
 285impl MultiBufferDimension for MultiBufferOffset {
 286    type TextDimension = usize;
 287    fn from_summary(summary: &MBTextSummary) -> Self {
 288        summary.len
 289    }
 290
 291    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 292        self.0 += *other;
 293    }
 294
 295    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 296        *self += summary.len;
 297    }
 298}
 299impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 300    type TextDimension = OffsetUtf16;
 301    fn from_summary(summary: &MBTextSummary) -> Self {
 302        MultiBufferOffsetUtf16(summary.len_utf16)
 303    }
 304
 305    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 306        self.0 += *other;
 307    }
 308
 309    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 310        self.0 += summary.len_utf16;
 311    }
 312}
 313
 314#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 315pub struct BufferOffset(pub usize);
 316
 317impl TextDimension for BufferOffset {
 318    fn from_text_summary(summary: &TextSummary) -> Self {
 319        BufferOffset(usize::from_text_summary(summary))
 320    }
 321    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 322        BufferOffset(usize::from_chunk(chunk))
 323    }
 324    fn add_assign(&mut self, other: &Self) {
 325        TextDimension::add_assign(&mut self.0, &other.0);
 326    }
 327}
 328impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 329    fn zero(cx: ()) -> Self {
 330        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 331    }
 332
 333    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 334        usize::add_summary(&mut self.0, summary, cx);
 335    }
 336}
 337
 338impl Sub for BufferOffset {
 339    type Output = usize;
 340
 341    fn sub(self, other: BufferOffset) -> Self::Output {
 342        self.0 - other.0
 343    }
 344}
 345
 346impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 347    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 348        self.0 += other.key;
 349    }
 350}
 351
 352impl language::ToPoint for BufferOffset {
 353    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 354        self.0.to_point(snapshot)
 355    }
 356}
 357
 358impl language::ToPointUtf16 for BufferOffset {
 359    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 360        self.0.to_point_utf16(snapshot)
 361    }
 362}
 363
 364impl language::ToOffset for BufferOffset {
 365    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 366        self.0.to_offset(snapshot)
 367    }
 368}
 369
 370impl language::ToOffsetUtf16 for BufferOffset {
 371    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 372        self.0.to_offset_utf16(snapshot)
 373    }
 374}
 375
 376#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 377pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 378
 379impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 380    type Output = MultiBufferOffsetUtf16;
 381
 382    fn add(self, rhs: usize) -> Self::Output {
 383        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 384    }
 385}
 386
 387impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 388    type Output = Self;
 389
 390    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 391        MultiBufferOffsetUtf16(self.0 + rhs)
 392    }
 393}
 394
 395impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 396    fn add_assign(&mut self, rhs: OffsetUtf16) {
 397        self.0 += rhs;
 398    }
 399}
 400
 401impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 402    fn add_assign(&mut self, rhs: usize) {
 403        self.0.0 += rhs;
 404    }
 405}
 406
 407impl Sub for MultiBufferOffsetUtf16 {
 408    type Output = OffsetUtf16;
 409
 410    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 411        self.0 - other.0
 412    }
 413}
 414
 415impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 416    type Output = MultiBufferOffsetUtf16;
 417
 418    fn sub(self, other: OffsetUtf16) -> Self::Output {
 419        MultiBufferOffsetUtf16(self.0 - other)
 420    }
 421}
 422
 423#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 424pub struct BufferOffsetUtf16(pub OffsetUtf16);
 425
 426impl MultiBufferOffset {
 427    const ZERO: Self = Self(0);
 428    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 429        self.0.saturating_sub(other.0)
 430    }
 431    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 432        MultiBufferOffset(self.0.saturating_sub(other))
 433    }
 434}
 435
 436impl ops::Sub for MultiBufferOffset {
 437    type Output = usize;
 438
 439    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 440        self.0 - other.0
 441    }
 442}
 443
 444impl ops::Sub<usize> for MultiBufferOffset {
 445    type Output = Self;
 446
 447    fn sub(self, other: usize) -> Self::Output {
 448        MultiBufferOffset(self.0 - other)
 449    }
 450}
 451
 452impl ops::SubAssign<usize> for MultiBufferOffset {
 453    fn sub_assign(&mut self, other: usize) {
 454        self.0 -= other;
 455    }
 456}
 457
 458impl ops::Add<usize> for BufferOffset {
 459    type Output = Self;
 460
 461    fn add(self, rhs: usize) -> Self::Output {
 462        BufferOffset(self.0 + rhs)
 463    }
 464}
 465
 466impl ops::AddAssign<usize> for BufferOffset {
 467    fn add_assign(&mut self, other: usize) {
 468        self.0 += other;
 469    }
 470}
 471
 472impl ops::Add<usize> for MultiBufferOffset {
 473    type Output = Self;
 474
 475    fn add(self, rhs: usize) -> Self::Output {
 476        MultiBufferOffset(self.0 + rhs)
 477    }
 478}
 479
 480impl ops::AddAssign<usize> for MultiBufferOffset {
 481    fn add_assign(&mut self, other: usize) {
 482        self.0 += other;
 483    }
 484}
 485
 486impl ops::Add<isize> for MultiBufferOffset {
 487    type Output = Self;
 488
 489    fn add(self, rhs: isize) -> Self::Output {
 490        MultiBufferOffset((self.0 as isize + rhs) as usize)
 491    }
 492}
 493
 494impl ops::Add for MultiBufferOffset {
 495    type Output = Self;
 496
 497    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 498        MultiBufferOffset(self.0 + rhs.0)
 499    }
 500}
 501
 502impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 503    fn add_assign(&mut self, other: MultiBufferOffset) {
 504        self.0 += other.0;
 505    }
 506}
 507
 508pub trait ToOffset: 'static + fmt::Debug {
 509    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 510    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 511}
 512
 513pub trait ToPoint: 'static + fmt::Debug {
 514    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 515    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 516}
 517
 518struct BufferState {
 519    buffer: Entity<Buffer>,
 520    last_version: RefCell<clock::Global>,
 521    last_non_text_state_update_count: Cell<usize>,
 522    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 523    excerpts: Vec<Locator>,
 524    _subscriptions: [gpui::Subscription; 2],
 525}
 526
 527struct DiffState {
 528    diff: Entity<BufferDiff>,
 529    main_buffer: Option<Entity<language::Buffer>>,
 530    _subscription: gpui::Subscription,
 531}
 532
 533impl DiffState {
 534    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 535        DiffStateSnapshot {
 536            diff: self.diff.read(cx).snapshot(cx),
 537            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 538        }
 539    }
 540}
 541
 542#[derive(Clone)]
 543struct DiffStateSnapshot {
 544    diff: BufferDiffSnapshot,
 545    main_buffer: Option<language::BufferSnapshot>,
 546}
 547
 548impl std::ops::Deref for DiffStateSnapshot {
 549    type Target = BufferDiffSnapshot;
 550
 551    fn deref(&self) -> &Self::Target {
 552        &self.diff
 553    }
 554}
 555
 556impl DiffState {
 557    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 558        DiffState {
 559            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 560                BufferDiffEvent::DiffChanged(DiffChanged {
 561                    changed_range,
 562                    base_text_changed_range: _,
 563                    extended_range,
 564                }) => {
 565                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 566                    let range = if use_extended {
 567                        extended_range.clone()
 568                    } else {
 569                        changed_range.clone()
 570                    };
 571                    if let Some(range) = range {
 572                        this.buffer_diff_changed(diff, range, cx)
 573                    }
 574                    cx.emit(Event::BufferDiffChanged);
 575                }
 576                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 577                _ => {}
 578            }),
 579            diff,
 580            main_buffer: None,
 581        }
 582    }
 583
 584    fn new_inverted(
 585        diff: Entity<BufferDiff>,
 586        main_buffer: Entity<language::Buffer>,
 587        cx: &mut Context<MultiBuffer>,
 588    ) -> Self {
 589        let weak_main_buffer = main_buffer.downgrade();
 590        DiffState {
 591            _subscription: cx.subscribe(&diff, {
 592                move |this, diff, event, cx| {
 593                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 594                        return;
 595                    };
 596                    match event {
 597                        BufferDiffEvent::DiffChanged(DiffChanged {
 598                            changed_range: _,
 599                            base_text_changed_range,
 600                            extended_range: _,
 601                        }) => {
 602                            this.inverted_buffer_diff_changed(
 603                                diff,
 604                                main_buffer,
 605                                base_text_changed_range.clone(),
 606                                cx,
 607                            );
 608                            cx.emit(Event::BufferDiffChanged);
 609                        }
 610                        BufferDiffEvent::LanguageChanged => {
 611                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 612                        }
 613                        _ => {}
 614                    }
 615                }
 616            }),
 617            diff,
 618            main_buffer: Some(main_buffer),
 619        }
 620    }
 621}
 622
 623/// The contents of a [`MultiBuffer`] at a single point in time.
 624#[derive(Clone, Default)]
 625pub struct MultiBufferSnapshot {
 626    excerpts: SumTree<Excerpt>,
 627    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 628    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 629    diff_transforms: SumTree<DiffTransform>,
 630    excerpt_ids: SumTree<ExcerptIdMapping>,
 631    replaced_excerpts: Arc<HashMap<ExcerptId, ExcerptId>>,
 632    non_text_state_update_count: usize,
 633    edit_count: usize,
 634    is_dirty: bool,
 635    has_deleted_file: bool,
 636    has_conflict: bool,
 637    has_inverted_diff: bool,
 638    singleton: bool,
 639    trailing_excerpt_update_count: usize,
 640    all_diff_hunks_expanded: bool,
 641    show_deleted_hunks: bool,
 642    use_extended_diff_range: bool,
 643    show_headers: bool,
 644}
 645
 646// follower: None
 647// - BufferContent(Some)
 648// - BufferContent(None)
 649// - DeletedHunk
 650//
 651// follower: Some
 652// - BufferContent(Some)
 653// - BufferContent(None)
 654
 655#[derive(Debug, Clone)]
 656enum DiffTransform {
 657    // RealText
 658    BufferContent {
 659        summary: MBTextSummary,
 660        // modified_hunk_info
 661        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 662    },
 663    // ExpandedHunkText
 664    DeletedHunk {
 665        summary: TextSummary,
 666        buffer_id: BufferId,
 667        hunk_info: DiffTransformHunkInfo,
 668        base_text_byte_range: Range<usize>,
 669        has_trailing_newline: bool,
 670    },
 671}
 672
 673#[derive(Clone, Copy, Debug)]
 674struct DiffTransformHunkInfo {
 675    excerpt_id: ExcerptId,
 676    hunk_start_anchor: text::Anchor,
 677    hunk_secondary_status: DiffHunkSecondaryStatus,
 678    is_logically_deleted: bool,
 679}
 680
 681impl Eq for DiffTransformHunkInfo {}
 682
 683impl PartialEq for DiffTransformHunkInfo {
 684    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 685        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 686    }
 687}
 688
 689impl std::hash::Hash for DiffTransformHunkInfo {
 690    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 691        self.excerpt_id.hash(state);
 692        self.hunk_start_anchor.hash(state);
 693    }
 694}
 695
 696#[derive(Clone)]
 697pub struct ExcerptInfo {
 698    pub id: ExcerptId,
 699    pub buffer: Arc<BufferSnapshot>,
 700    pub buffer_id: BufferId,
 701    pub range: ExcerptRange<text::Anchor>,
 702    pub end_row: MultiBufferRow,
 703}
 704
 705impl std::fmt::Debug for ExcerptInfo {
 706    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 707        f.debug_struct(type_name::<Self>())
 708            .field("id", &self.id)
 709            .field("buffer_id", &self.buffer_id)
 710            .field("path", &self.buffer.file().map(|f| f.path()))
 711            .field("range", &self.range)
 712            .finish()
 713    }
 714}
 715
 716/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 717#[derive(Debug)]
 718pub struct ExcerptBoundary {
 719    pub prev: Option<ExcerptInfo>,
 720    pub next: ExcerptInfo,
 721    /// The row in the `MultiBuffer` where the boundary is located
 722    pub row: MultiBufferRow,
 723}
 724
 725impl ExcerptBoundary {
 726    pub fn starts_new_buffer(&self) -> bool {
 727        match (self.prev.as_ref(), &self.next) {
 728            (None, _) => true,
 729            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 730        }
 731    }
 732}
 733
 734#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 735pub struct ExpandInfo {
 736    pub direction: ExpandExcerptDirection,
 737    pub excerpt_id: ExcerptId,
 738}
 739
 740#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 741pub struct RowInfo {
 742    pub buffer_id: Option<BufferId>,
 743    pub buffer_row: Option<u32>,
 744    pub multibuffer_row: Option<MultiBufferRow>,
 745    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 746    pub expand_info: Option<ExpandInfo>,
 747    pub wrapped_buffer_row: Option<u32>,
 748}
 749
 750/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 751#[derive(Clone)]
 752struct Excerpt {
 753    /// The unique identifier for this excerpt
 754    id: ExcerptId,
 755    /// The location of the excerpt in the [`MultiBuffer`]
 756    locator: Locator,
 757    /// The buffer being excerpted
 758    buffer_id: BufferId,
 759    /// A snapshot of the buffer being excerpted
 760    buffer: Arc<BufferSnapshot>,
 761    /// The range of the buffer to be shown in the excerpt
 762    range: ExcerptRange<text::Anchor>,
 763    /// The last row in the excerpted slice of the buffer
 764    max_buffer_row: BufferRow,
 765    /// A summary of the text in the excerpt
 766    text_summary: TextSummary,
 767    has_trailing_newline: bool,
 768}
 769
 770/// A public view into an `Excerpt` in a [`MultiBuffer`].
 771///
 772/// Contains methods for getting the [`Buffer`] of the excerpt,
 773/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 774#[derive(Clone)]
 775pub struct MultiBufferExcerpt<'a> {
 776    excerpt: &'a Excerpt,
 777    diff_transforms:
 778        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 779    /// The offset in the multibuffer considering diff transforms.
 780    offset: MultiBufferOffset,
 781    /// The offset in the multibuffer without diff transforms.
 782    excerpt_offset: ExcerptOffset,
 783    buffer_offset: BufferOffset,
 784}
 785
 786#[derive(Clone, Debug)]
 787struct ExcerptIdMapping {
 788    id: ExcerptId,
 789    locator: Locator,
 790}
 791
 792/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 793/// These ranges are relative to the buffer itself
 794#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 795pub struct ExcerptRange<T> {
 796    /// The full range of text to be shown in the excerpt.
 797    pub context: Range<T>,
 798    /// The primary range of text to be highlighted in the excerpt.
 799    /// In a multi-buffer search, this would be the text that matched the search
 800    pub primary: Range<T>,
 801}
 802
 803impl<T: Clone> ExcerptRange<T> {
 804    pub fn new(context: Range<T>) -> Self {
 805        Self {
 806            context: context.clone(),
 807            primary: context,
 808        }
 809    }
 810}
 811
 812#[derive(Clone, Debug, Default)]
 813pub struct ExcerptSummary {
 814    excerpt_id: ExcerptId,
 815    /// The location of the last [`Excerpt`] being summarized
 816    excerpt_locator: Locator,
 817    widest_line_number: u32,
 818    text: MBTextSummary,
 819    count: usize,
 820}
 821
 822#[derive(Debug, Clone)]
 823pub struct DiffTransformSummary {
 824    input: MBTextSummary,
 825    output: MBTextSummary,
 826}
 827
 828/// Summary of a string of text.
 829#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 830pub struct MBTextSummary {
 831    /// Length in bytes.
 832    pub len: MultiBufferOffset,
 833    /// Length in UTF-8.
 834    pub chars: usize,
 835    /// Length in UTF-16 code units
 836    pub len_utf16: OffsetUtf16,
 837    /// A point representing the number of lines and the length of the last line.
 838    ///
 839    /// In other words, it marks the point after the last byte in the text, (if
 840    /// EOF was a character, this would be its position).
 841    pub lines: Point,
 842    /// How many `char`s are in the first line
 843    pub first_line_chars: u32,
 844    /// How many `char`s are in the last line
 845    pub last_line_chars: u32,
 846    /// How many UTF-16 code units are in the last line
 847    pub last_line_len_utf16: u32,
 848    /// The row idx of the longest row
 849    pub longest_row: u32,
 850    /// How many `char`s are in the longest row
 851    pub longest_row_chars: u32,
 852}
 853
 854impl From<TextSummary> for MBTextSummary {
 855    fn from(summary: TextSummary) -> Self {
 856        MBTextSummary {
 857            len: MultiBufferOffset(summary.len),
 858            chars: summary.chars,
 859            len_utf16: summary.len_utf16,
 860            lines: summary.lines,
 861            first_line_chars: summary.first_line_chars,
 862            last_line_chars: summary.last_line_chars,
 863            last_line_len_utf16: summary.last_line_len_utf16,
 864            longest_row: summary.longest_row,
 865            longest_row_chars: summary.longest_row_chars,
 866        }
 867    }
 868}
 869
 870impl From<MBTextSummary> for TextSummary {
 871    fn from(summary: MBTextSummary) -> Self {
 872        TextSummary {
 873            len: summary.len.0,
 874            chars: summary.chars,
 875            len_utf16: summary.len_utf16,
 876            lines: summary.lines,
 877            first_line_chars: summary.first_line_chars,
 878            last_line_chars: summary.last_line_chars,
 879            last_line_len_utf16: summary.last_line_len_utf16,
 880            longest_row: summary.longest_row,
 881            longest_row_chars: summary.longest_row_chars,
 882        }
 883    }
 884}
 885
 886impl From<&str> for MBTextSummary {
 887    fn from(text: &str) -> Self {
 888        MBTextSummary::from(TextSummary::from(text))
 889    }
 890}
 891
 892impl MultiBufferDimension for MBTextSummary {
 893    type TextDimension = TextSummary;
 894
 895    fn from_summary(summary: &MBTextSummary) -> Self {
 896        *summary
 897    }
 898
 899    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 900        *self += *summary;
 901    }
 902
 903    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 904        *self += *summary;
 905    }
 906}
 907
 908impl AddAssign for MBTextSummary {
 909    fn add_assign(&mut self, other: MBTextSummary) {
 910        let joined_chars = self.last_line_chars + other.first_line_chars;
 911        if joined_chars > self.longest_row_chars {
 912            self.longest_row = self.lines.row;
 913            self.longest_row_chars = joined_chars;
 914        }
 915        if other.longest_row_chars > self.longest_row_chars {
 916            self.longest_row = self.lines.row + other.longest_row;
 917            self.longest_row_chars = other.longest_row_chars;
 918        }
 919
 920        if self.lines.row == 0 {
 921            self.first_line_chars += other.first_line_chars;
 922        }
 923
 924        if other.lines.row == 0 {
 925            self.last_line_chars += other.first_line_chars;
 926            self.last_line_len_utf16 += other.last_line_len_utf16;
 927        } else {
 928            self.last_line_chars = other.last_line_chars;
 929            self.last_line_len_utf16 = other.last_line_len_utf16;
 930        }
 931
 932        self.chars += other.chars;
 933        self.len += other.len;
 934        self.len_utf16 += other.len_utf16;
 935        self.lines += other.lines;
 936    }
 937}
 938
 939impl AddAssign<TextSummary> for MBTextSummary {
 940    fn add_assign(&mut self, other: TextSummary) {
 941        *self += MBTextSummary::from(other);
 942    }
 943}
 944
 945impl MBTextSummary {
 946    pub fn lines_utf16(&self) -> PointUtf16 {
 947        PointUtf16 {
 948            row: self.lines.row,
 949            column: self.last_line_len_utf16,
 950        }
 951    }
 952}
 953
 954impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 955where
 956    K: MultiBufferDimension,
 957    V: MultiBufferDimension,
 958{
 959    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 960
 961    fn from_summary(summary: &MBTextSummary) -> Self {
 962        Self {
 963            key: K::from_summary(summary),
 964            value: Some(V::from_summary(summary)),
 965        }
 966    }
 967
 968    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 969        self.key.add_text_dim(&summary.key);
 970        if let Some(value) = &mut self.value {
 971            if let Some(other_value) = summary.value.as_ref() {
 972                value.add_text_dim(other_value);
 973            }
 974        }
 975    }
 976
 977    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 978        self.key.add_mb_text_summary(summary);
 979        if let Some(value) = &mut self.value {
 980            value.add_mb_text_summary(summary);
 981        }
 982    }
 983}
 984
 985#[derive(Clone)]
 986pub struct MultiBufferRows<'a> {
 987    point: Point,
 988    is_empty: bool,
 989    is_singleton: bool,
 990    cursor: MultiBufferCursor<'a, Point, Point>,
 991}
 992
 993pub struct MultiBufferChunks<'a> {
 994    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 995    diff_transforms:
 996        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 997    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 998    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 999    buffer_chunk: Option<Chunk<'a>>,
1000    range: Range<MultiBufferOffset>,
1001    excerpt_offset_range: Range<ExcerptOffset>,
1002    excerpt_chunks: Option<ExcerptChunks<'a>>,
1003    language_aware: bool,
1004}
1005
1006pub struct ReversedMultiBufferChunks<'a> {
1007    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1008    current_chunks: Option<rope::Chunks<'a>>,
1009    start: MultiBufferOffset,
1010    offset: MultiBufferOffset,
1011}
1012
1013pub struct MultiBufferBytes<'a> {
1014    range: Range<MultiBufferOffset>,
1015    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1016    excerpt_bytes: Option<text::Bytes<'a>>,
1017    has_trailing_newline: bool,
1018    chunk: &'a [u8],
1019}
1020
1021pub struct ReversedMultiBufferBytes<'a> {
1022    range: Range<MultiBufferOffset>,
1023    chunks: ReversedMultiBufferChunks<'a>,
1024    chunk: &'a [u8],
1025}
1026
1027#[derive(Clone)]
1028struct DiffTransforms<MBD> {
1029    output_dimension: OutputDimension<MBD>,
1030    excerpt_dimension: ExcerptDimension<MBD>,
1031}
1032
1033impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1034    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1035        Self {
1036            output_dimension: OutputDimension::zero(cx),
1037            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1038                cx,
1039            ),
1040        }
1041    }
1042
1043    fn add_summary(
1044        &mut self,
1045        summary: &'a DiffTransformSummary,
1046        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1047    ) {
1048        self.output_dimension.add_summary(summary, cx);
1049        self.excerpt_dimension.add_summary(summary, cx);
1050    }
1051}
1052
1053#[derive(Clone)]
1054struct MultiBufferCursor<'a, MBD, BD> {
1055    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1056    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1057    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1058    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1059}
1060
1061#[derive(Clone)]
1062struct MultiBufferRegion<'a, MBD, BD> {
1063    buffer: &'a BufferSnapshot,
1064    is_main_buffer: bool,
1065    diff_hunk_status: Option<DiffHunkStatus>,
1066    excerpt: &'a Excerpt,
1067    buffer_range: Range<BD>,
1068    range: Range<MBD>,
1069    has_trailing_newline: bool,
1070}
1071
1072struct ExcerptChunks<'a> {
1073    excerpt_id: ExcerptId,
1074    content_chunks: BufferChunks<'a>,
1075    has_footer: bool,
1076}
1077
1078#[derive(Debug)]
1079struct BufferEdit {
1080    range: Range<BufferOffset>,
1081    new_text: Arc<str>,
1082    is_insertion: bool,
1083    original_indent_column: Option<u32>,
1084    excerpt_id: ExcerptId,
1085}
1086
1087#[derive(Clone, Copy, Debug, PartialEq)]
1088enum DiffChangeKind {
1089    BufferEdited,
1090    DiffUpdated { base_changed: bool },
1091    ExpandOrCollapseHunks { expand: bool },
1092}
1093
1094#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1095pub enum ExpandExcerptDirection {
1096    Up,
1097    Down,
1098    UpAndDown,
1099}
1100
1101impl ExpandExcerptDirection {
1102    pub fn should_expand_up(&self) -> bool {
1103        match self {
1104            ExpandExcerptDirection::Up => true,
1105            ExpandExcerptDirection::Down => false,
1106            ExpandExcerptDirection::UpAndDown => true,
1107        }
1108    }
1109
1110    pub fn should_expand_down(&self) -> bool {
1111        match self {
1112            ExpandExcerptDirection::Up => false,
1113            ExpandExcerptDirection::Down => true,
1114            ExpandExcerptDirection::UpAndDown => true,
1115        }
1116    }
1117}
1118
1119#[derive(Clone, Debug, PartialEq)]
1120pub struct IndentGuide {
1121    pub buffer_id: BufferId,
1122    pub start_row: MultiBufferRow,
1123    pub end_row: MultiBufferRow,
1124    pub depth: u32,
1125    pub tab_size: u32,
1126    pub settings: IndentGuideSettings,
1127}
1128
1129impl IndentGuide {
1130    pub fn indent_level(&self) -> u32 {
1131        self.depth * self.tab_size
1132    }
1133}
1134
1135impl MultiBuffer {
1136    pub fn new(capability: Capability) -> Self {
1137        Self::new_(
1138            capability,
1139            MultiBufferSnapshot {
1140                show_headers: true,
1141                show_deleted_hunks: true,
1142                ..MultiBufferSnapshot::default()
1143            },
1144        )
1145    }
1146
1147    pub fn without_headers(capability: Capability) -> Self {
1148        Self::new_(
1149            capability,
1150            MultiBufferSnapshot {
1151                show_deleted_hunks: true,
1152                ..MultiBufferSnapshot::default()
1153            },
1154        )
1155    }
1156
1157    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1158        let mut this = Self::new_(
1159            buffer.read(cx).capability(),
1160            MultiBufferSnapshot {
1161                singleton: true,
1162                show_deleted_hunks: true,
1163                ..MultiBufferSnapshot::default()
1164            },
1165        );
1166        this.singleton = true;
1167        this.set_excerpts_for_path(
1168            PathKey::sorted(0),
1169            buffer.clone(),
1170            [Point::zero()..buffer.read(cx).max_point()],
1171            0,
1172            cx,
1173        );
1174        this
1175    }
1176
1177    #[inline]
1178    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1179        Self {
1180            snapshot: RefCell::new(snapshot),
1181            buffers: Default::default(),
1182            diffs: HashMap::default(),
1183            subscriptions: Topic::default(),
1184            singleton: false,
1185            capability,
1186            title: None,
1187            excerpts_by_path: Default::default(),
1188            paths_by_excerpt: Default::default(),
1189            buffer_changed_since_sync: Default::default(),
1190            history: History::default(),
1191        }
1192    }
1193
1194    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1195        let mut buffers = BTreeMap::default();
1196        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1197        for (buffer_id, buffer_state) in self.buffers.iter() {
1198            buffer_state.buffer.update(new_cx, |buffer, _| {
1199                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1200            });
1201            buffers.insert(
1202                *buffer_id,
1203                BufferState {
1204                    buffer: buffer_state.buffer.clone(),
1205                    last_version: buffer_state.last_version.clone(),
1206                    last_non_text_state_update_count: buffer_state
1207                        .last_non_text_state_update_count
1208                        .clone(),
1209                    excerpts: buffer_state.excerpts.clone(),
1210                    _subscriptions: [
1211                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1212                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1213                    ],
1214                },
1215            );
1216        }
1217        let mut diff_bases = HashMap::default();
1218        for (buffer_id, diff) in self.diffs.iter() {
1219            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1220        }
1221        Self {
1222            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1223            buffers,
1224            excerpts_by_path: Default::default(),
1225            paths_by_excerpt: Default::default(),
1226            diffs: diff_bases,
1227            subscriptions: Default::default(),
1228            singleton: self.singleton,
1229            capability: self.capability,
1230            history: self.history.clone(),
1231            title: self.title.clone(),
1232            buffer_changed_since_sync,
1233        }
1234    }
1235
1236    pub fn set_group_interval(&mut self, group_interval: Duration) {
1237        self.history.set_group_interval(group_interval);
1238    }
1239
1240    pub fn with_title(mut self, title: String) -> Self {
1241        self.title = Some(title);
1242        self
1243    }
1244
1245    pub fn read_only(&self) -> bool {
1246        !self.capability.editable()
1247    }
1248
1249    pub fn capability(&self) -> Capability {
1250        self.capability
1251    }
1252
1253    /// Returns an up-to-date snapshot of the MultiBuffer.
1254    #[ztracing::instrument(skip_all)]
1255    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1256        self.sync(cx);
1257        self.snapshot.borrow().clone()
1258    }
1259
1260    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1261        self.sync(cx);
1262        self.snapshot.borrow()
1263    }
1264
1265    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1266        if self.singleton {
1267            Some(self.buffers.values().next().unwrap().buffer.clone())
1268        } else {
1269            None
1270        }
1271    }
1272
1273    pub fn is_singleton(&self) -> bool {
1274        self.singleton
1275    }
1276
1277    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1278        self.subscriptions.subscribe()
1279    }
1280
1281    pub fn is_dirty(&self, cx: &App) -> bool {
1282        self.read(cx).is_dirty()
1283    }
1284
1285    pub fn has_deleted_file(&self, cx: &App) -> bool {
1286        self.read(cx).has_deleted_file()
1287    }
1288
1289    pub fn has_conflict(&self, cx: &App) -> bool {
1290        self.read(cx).has_conflict()
1291    }
1292
1293    // The `is_empty` signature doesn't match what clippy expects
1294    #[allow(clippy::len_without_is_empty)]
1295    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1296        self.read(cx).len()
1297    }
1298
1299    pub fn is_empty(&self) -> bool {
1300        self.buffers.is_empty()
1301    }
1302
1303    pub fn edit<I, S, T>(
1304        &mut self,
1305        edits: I,
1306        autoindent_mode: Option<AutoindentMode>,
1307        cx: &mut Context<Self>,
1308    ) where
1309        I: IntoIterator<Item = (Range<S>, T)>,
1310        S: ToOffset,
1311        T: Into<Arc<str>>,
1312    {
1313        self.edit_internal(edits, autoindent_mode, true, cx);
1314    }
1315
1316    pub fn edit_non_coalesce<I, S, T>(
1317        &mut self,
1318        edits: I,
1319        autoindent_mode: Option<AutoindentMode>,
1320        cx: &mut Context<Self>,
1321    ) where
1322        I: IntoIterator<Item = (Range<S>, T)>,
1323        S: ToOffset,
1324        T: Into<Arc<str>>,
1325    {
1326        self.edit_internal(edits, autoindent_mode, false, cx);
1327    }
1328
1329    fn edit_internal<I, S, T>(
1330        &mut self,
1331        edits: I,
1332        autoindent_mode: Option<AutoindentMode>,
1333        coalesce_adjacent: bool,
1334        cx: &mut Context<Self>,
1335    ) where
1336        I: IntoIterator<Item = (Range<S>, T)>,
1337        S: ToOffset,
1338        T: Into<Arc<str>>,
1339    {
1340        if self.read_only() || self.buffers.is_empty() {
1341            return;
1342        }
1343        self.sync_mut(cx);
1344        let edits = edits
1345            .into_iter()
1346            .map(|(range, new_text)| {
1347                let mut range = range.start.to_offset(self.snapshot.get_mut())
1348                    ..range.end.to_offset(self.snapshot.get_mut());
1349                if range.start > range.end {
1350                    mem::swap(&mut range.start, &mut range.end);
1351                }
1352                (range, new_text.into())
1353            })
1354            .collect::<Vec<_>>();
1355
1356        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1357
1358        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1359        fn edit_internal(
1360            this: &mut MultiBuffer,
1361            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1362            mut autoindent_mode: Option<AutoindentMode>,
1363            coalesce_adjacent: bool,
1364            cx: &mut Context<MultiBuffer>,
1365        ) {
1366            let original_indent_columns = match &mut autoindent_mode {
1367                Some(AutoindentMode::Block {
1368                    original_indent_columns,
1369                }) => mem::take(original_indent_columns),
1370                _ => Default::default(),
1371            };
1372
1373            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1374                edits,
1375                this.snapshot.get_mut(),
1376                &original_indent_columns,
1377            );
1378
1379            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1380            for (buffer_id, mut edits) in buffer_edits {
1381                buffer_ids.push(buffer_id);
1382                edits.sort_by_key(|edit| edit.range.start);
1383                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1384                    let mut edits = edits.into_iter().peekable();
1385                    let mut insertions = Vec::new();
1386                    let mut original_indent_columns = Vec::new();
1387                    let mut deletions = Vec::new();
1388                    let empty_str: Arc<str> = Arc::default();
1389                    while let Some(BufferEdit {
1390                        mut range,
1391                        mut new_text,
1392                        mut is_insertion,
1393                        original_indent_column,
1394                        excerpt_id,
1395                    }) = edits.next()
1396                    {
1397                        while let Some(BufferEdit {
1398                            range: next_range,
1399                            is_insertion: next_is_insertion,
1400                            new_text: next_new_text,
1401                            excerpt_id: next_excerpt_id,
1402                            ..
1403                        }) = edits.peek()
1404                        {
1405                            let should_coalesce = if coalesce_adjacent {
1406                                range.end >= next_range.start
1407                            } else {
1408                                range.end > next_range.start
1409                            };
1410
1411                            if should_coalesce {
1412                                range.end = cmp::max(next_range.end, range.end);
1413                                is_insertion |= *next_is_insertion;
1414                                if excerpt_id == *next_excerpt_id {
1415                                    new_text = format!("{new_text}{next_new_text}").into();
1416                                }
1417                                edits.next();
1418                            } else {
1419                                break;
1420                            }
1421                        }
1422
1423                        if is_insertion {
1424                            original_indent_columns.push(original_indent_column);
1425                            insertions.push((
1426                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1427                                new_text.clone(),
1428                            ));
1429                        } else if !range.is_empty() {
1430                            deletions.push((
1431                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1432                                empty_str.clone(),
1433                            ));
1434                        }
1435                    }
1436
1437                    let deletion_autoindent_mode =
1438                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1439                            Some(AutoindentMode::Block {
1440                                original_indent_columns: Default::default(),
1441                            })
1442                        } else {
1443                            autoindent_mode.clone()
1444                        };
1445                    let insertion_autoindent_mode =
1446                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1447                            Some(AutoindentMode::Block {
1448                                original_indent_columns,
1449                            })
1450                        } else {
1451                            autoindent_mode.clone()
1452                        };
1453
1454                    if coalesce_adjacent {
1455                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1456                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1457                    } else {
1458                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1459                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1460                    }
1461                })
1462            }
1463
1464            cx.emit(Event::ExcerptsEdited {
1465                excerpt_ids: edited_excerpt_ids,
1466                buffer_ids,
1467            });
1468        }
1469    }
1470
1471    fn convert_edits_to_buffer_edits(
1472        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1473        snapshot: &MultiBufferSnapshot,
1474        original_indent_columns: &[Option<u32>],
1475    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1476        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1477        let mut edited_excerpt_ids = Vec::new();
1478        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1479        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1480            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1481
1482            cursor.seek(&range.start);
1483            let mut start_region = cursor.region().expect("start offset out of bounds");
1484            if !start_region.is_main_buffer {
1485                cursor.next();
1486                if let Some(region) = cursor.region() {
1487                    start_region = region;
1488                } else {
1489                    continue;
1490                }
1491            }
1492
1493            if range.end < start_region.range.start {
1494                continue;
1495            }
1496
1497            let start_region = start_region.clone();
1498            if range.end > start_region.range.end {
1499                cursor.seek_forward(&range.end);
1500            }
1501            let mut end_region = cursor.region().expect("end offset out of bounds");
1502            if !end_region.is_main_buffer {
1503                cursor.prev();
1504                if let Some(region) = cursor.region() {
1505                    end_region = region;
1506                } else {
1507                    continue;
1508                }
1509            }
1510
1511            if range.start > end_region.range.end {
1512                continue;
1513            }
1514
1515            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1516            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1517            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1518                .min(start_region.buffer_range.end);
1519            let buffer_end =
1520                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1521
1522            if start_region.excerpt.id == end_region.excerpt.id {
1523                if start_region.buffer.capability == Capability::ReadWrite
1524                    && start_region.is_main_buffer
1525                {
1526                    edited_excerpt_ids.push(start_region.excerpt.id);
1527                    buffer_edits
1528                        .entry(start_region.buffer.remote_id())
1529                        .or_default()
1530                        .push(BufferEdit {
1531                            range: buffer_start..buffer_end,
1532                            new_text,
1533                            is_insertion: true,
1534                            original_indent_column,
1535                            excerpt_id: start_region.excerpt.id,
1536                        });
1537                }
1538            } else {
1539                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1540                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1541                if start_region.buffer.capability == Capability::ReadWrite
1542                    && start_region.is_main_buffer
1543                {
1544                    edited_excerpt_ids.push(start_region.excerpt.id);
1545                    buffer_edits
1546                        .entry(start_region.buffer.remote_id())
1547                        .or_default()
1548                        .push(BufferEdit {
1549                            range: start_excerpt_range,
1550                            new_text: new_text.clone(),
1551                            is_insertion: true,
1552                            original_indent_column,
1553                            excerpt_id: start_region.excerpt.id,
1554                        });
1555                }
1556                let excerpt_id = end_region.excerpt.id;
1557                if end_region.buffer.capability == Capability::ReadWrite
1558                    && end_region.is_main_buffer
1559                {
1560                    edited_excerpt_ids.push(excerpt_id);
1561                    buffer_edits
1562                        .entry(end_region.buffer.remote_id())
1563                        .or_default()
1564                        .push(BufferEdit {
1565                            range: end_excerpt_range,
1566                            new_text: new_text.clone(),
1567                            is_insertion: false,
1568                            original_indent_column,
1569                            excerpt_id,
1570                        });
1571                }
1572
1573                cursor.seek(&range.start);
1574                cursor.next_excerpt();
1575                while let Some(region) = cursor.region() {
1576                    if region.excerpt.id == excerpt_id {
1577                        break;
1578                    }
1579                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1580                        edited_excerpt_ids.push(region.excerpt.id);
1581                        buffer_edits
1582                            .entry(region.buffer.remote_id())
1583                            .or_default()
1584                            .push(BufferEdit {
1585                                range: region.buffer_range.clone(),
1586                                new_text: new_text.clone(),
1587                                is_insertion: false,
1588                                original_indent_column,
1589                                excerpt_id: region.excerpt.id,
1590                            });
1591                    }
1592                    cursor.next_excerpt();
1593                }
1594            }
1595        }
1596        (buffer_edits, edited_excerpt_ids)
1597    }
1598
1599    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1600    where
1601        I: IntoIterator<Item = Range<S>>,
1602        S: ToOffset,
1603    {
1604        if self.read_only() || self.buffers.is_empty() {
1605            return;
1606        }
1607        self.sync_mut(cx);
1608        let empty = Arc::<str>::from("");
1609        let edits = ranges
1610            .into_iter()
1611            .map(|range| {
1612                let mut range = range.start.to_offset(self.snapshot.get_mut())
1613                    ..range.end.to_offset(&self.snapshot.get_mut());
1614                if range.start > range.end {
1615                    mem::swap(&mut range.start, &mut range.end);
1616                }
1617                (range, empty.clone())
1618            })
1619            .collect::<Vec<_>>();
1620
1621        return autoindent_ranges_internal(self, edits, cx);
1622
1623        fn autoindent_ranges_internal(
1624            this: &mut MultiBuffer,
1625            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1626            cx: &mut Context<MultiBuffer>,
1627        ) {
1628            let (buffer_edits, edited_excerpt_ids) =
1629                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1630
1631            let mut buffer_ids = Vec::new();
1632            for (buffer_id, mut edits) in buffer_edits {
1633                buffer_ids.push(buffer_id);
1634                edits.sort_unstable_by_key(|edit| edit.range.start);
1635
1636                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1637                for edit in edits {
1638                    if let Some(last_range) = ranges.last_mut()
1639                        && edit.range.start <= last_range.end
1640                    {
1641                        last_range.end = last_range.end.max(edit.range.end);
1642                        continue;
1643                    }
1644                    ranges.push(edit.range);
1645                }
1646
1647                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1648                    buffer.autoindent_ranges(ranges, cx);
1649                })
1650            }
1651
1652            cx.emit(Event::ExcerptsEdited {
1653                excerpt_ids: edited_excerpt_ids,
1654                buffer_ids,
1655            });
1656        }
1657    }
1658
1659    pub fn set_active_selections(
1660        &self,
1661        selections: &[Selection<Anchor>],
1662        line_mode: bool,
1663        cursor_shape: CursorShape,
1664        cx: &mut Context<Self>,
1665    ) {
1666        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1667            Default::default();
1668        let snapshot = self.read(cx);
1669        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1670        for selection in selections {
1671            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1672            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1673
1674            cursor.seek(&Some(start_locator), Bias::Left);
1675            while let Some(excerpt) = cursor.item()
1676                && excerpt.locator <= *end_locator
1677            {
1678                let mut start = excerpt.range.context.start;
1679                let mut end = excerpt.range.context.end;
1680                if excerpt.id == selection.start.excerpt_id {
1681                    start = selection.start.text_anchor;
1682                }
1683                if excerpt.id == selection.end.excerpt_id {
1684                    end = selection.end.text_anchor;
1685                }
1686                selections_by_buffer
1687                    .entry(excerpt.buffer_id)
1688                    .or_default()
1689                    .push(Selection {
1690                        id: selection.id,
1691                        start,
1692                        end,
1693                        reversed: selection.reversed,
1694                        goal: selection.goal,
1695                    });
1696
1697                cursor.next();
1698            }
1699        }
1700
1701        for (buffer_id, buffer_state) in self.buffers.iter() {
1702            if !selections_by_buffer.contains_key(buffer_id) {
1703                buffer_state
1704                    .buffer
1705                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1706            }
1707        }
1708
1709        for (buffer_id, mut selections) in selections_by_buffer {
1710            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1711                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1712                let mut selections = selections.into_iter().peekable();
1713                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1714                    let mut selection = selections.next()?;
1715                    while let Some(next_selection) = selections.peek() {
1716                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1717                            let next_selection = selections.next().unwrap();
1718                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1719                                selection.end = next_selection.end;
1720                            }
1721                        } else {
1722                            break;
1723                        }
1724                    }
1725                    Some(selection)
1726                }));
1727                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1728            });
1729        }
1730    }
1731
1732    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1733        for buffer in self.buffers.values() {
1734            buffer
1735                .buffer
1736                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1737        }
1738    }
1739
1740    #[instrument(skip_all)]
1741    fn merge_excerpt_ranges<'a>(
1742        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1743    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1744        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1745        let mut counts: Vec<usize> = Vec::new();
1746        for range in expanded_ranges {
1747            if let Some(last_range) = merged_ranges.last_mut() {
1748                assert!(
1749                    last_range.context.start <= range.context.start,
1750                    "ranges must be sorted: {last_range:?} <= {range:?}"
1751                );
1752                if last_range.context.end >= range.context.start
1753                    || last_range.context.end.row + 1 == range.context.start.row
1754                {
1755                    last_range.context.end = range.context.end.max(last_range.context.end);
1756                    *counts.last_mut().unwrap() += 1;
1757                    continue;
1758                }
1759            }
1760            merged_ranges.push(range.clone());
1761            counts.push(1);
1762        }
1763        (merged_ranges, counts)
1764    }
1765
1766    pub fn insert_excerpts_after<O>(
1767        &mut self,
1768        prev_excerpt_id: ExcerptId,
1769        buffer: Entity<Buffer>,
1770        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1771        cx: &mut Context<Self>,
1772    ) -> Vec<ExcerptId>
1773    where
1774        O: text::ToOffset,
1775    {
1776        let mut ids = Vec::new();
1777        let mut next_excerpt_id =
1778            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1779                last_entry.id.0 + 1
1780            } else {
1781                1
1782            };
1783        self.insert_excerpts_with_ids_after(
1784            prev_excerpt_id,
1785            buffer,
1786            ranges.into_iter().map(|range| {
1787                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1788                ids.push(id);
1789                (id, range)
1790            }),
1791            cx,
1792        );
1793        ids
1794    }
1795
1796    pub fn insert_excerpts_with_ids_after<O>(
1797        &mut self,
1798        prev_excerpt_id: ExcerptId,
1799        buffer: Entity<Buffer>,
1800        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1801        cx: &mut Context<Self>,
1802    ) where
1803        O: text::ToOffset,
1804    {
1805        assert_eq!(self.history.transaction_depth(), 0);
1806        let mut ranges = ranges.into_iter().peekable();
1807        if ranges.peek().is_none() {
1808            return Default::default();
1809        }
1810
1811        self.sync_mut(cx);
1812
1813        let buffer_snapshot = buffer.read(cx).snapshot();
1814        let buffer_id = buffer_snapshot.remote_id();
1815
1816        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1817            self.buffer_changed_since_sync.replace(true);
1818            buffer.update(cx, |buffer, _| {
1819                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1820            });
1821            BufferState {
1822                last_version: RefCell::new(buffer_snapshot.version().clone()),
1823                last_non_text_state_update_count: Cell::new(
1824                    buffer_snapshot.non_text_state_update_count(),
1825                ),
1826                excerpts: Default::default(),
1827                _subscriptions: [
1828                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1829                    cx.subscribe(&buffer, Self::on_buffer_event),
1830                ],
1831                buffer: buffer.clone(),
1832            }
1833        });
1834
1835        let mut snapshot = self.snapshot.get_mut();
1836
1837        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1838        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1839        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1840        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1841        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1842
1843        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1844        new_excerpts.update_last(
1845            |excerpt| {
1846                excerpt.has_trailing_newline = true;
1847            },
1848            (),
1849        );
1850
1851        let next_locator = if let Some(excerpt) = cursor.item() {
1852            excerpt.locator.clone()
1853        } else {
1854            Locator::max()
1855        };
1856
1857        let mut excerpts = Vec::new();
1858        let buffer_snapshot = Arc::new(buffer_snapshot);
1859        while let Some((id, range)) = ranges.next() {
1860            let locator = Locator::between(&prev_locator, &next_locator);
1861            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1862                buffer_state.excerpts.insert(ix, locator.clone());
1863            }
1864            let range = ExcerptRange {
1865                context: buffer_snapshot.anchor_before(&range.context.start)
1866                    ..buffer_snapshot.anchor_after(&range.context.end),
1867                primary: buffer_snapshot.anchor_before(&range.primary.start)
1868                    ..buffer_snapshot.anchor_after(&range.primary.end),
1869            };
1870            excerpts.push((id, range.clone()));
1871            let excerpt = Excerpt::new(
1872                id,
1873                locator.clone(),
1874                buffer_id,
1875                buffer_snapshot.clone(),
1876                range,
1877                ranges.peek().is_some() || cursor.item().is_some(),
1878            );
1879            new_excerpts.push(excerpt, ());
1880            prev_locator = locator.clone();
1881
1882            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1883                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1884            }
1885            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1886        }
1887        snapshot
1888            .buffer_locators
1889            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1890
1891        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1892
1893        let suffix = cursor.suffix();
1894        let changed_trailing_excerpt = suffix.is_empty();
1895        new_excerpts.append(suffix, ());
1896        drop(cursor);
1897        snapshot.excerpts = new_excerpts;
1898        snapshot.excerpt_ids = new_excerpt_ids;
1899        if changed_trailing_excerpt {
1900            snapshot.trailing_excerpt_update_count += 1;
1901        }
1902
1903        let edits = Self::sync_diff_transforms(
1904            &mut snapshot,
1905            vec![Edit {
1906                old: edit_start..edit_start,
1907                new: edit_start..edit_end,
1908            }],
1909            DiffChangeKind::BufferEdited,
1910        );
1911        if !edits.is_empty() {
1912            self.subscriptions.publish(edits);
1913        }
1914
1915        cx.emit(Event::Edited {
1916            edited_buffer: None,
1917            is_local: true,
1918        });
1919        cx.emit(Event::ExcerptsAdded {
1920            buffer,
1921            predecessor: prev_excerpt_id,
1922            excerpts,
1923        });
1924        cx.notify();
1925    }
1926
1927    pub fn clear(&mut self, cx: &mut Context<Self>) {
1928        self.sync_mut(cx);
1929        let ids = self.excerpt_ids();
1930        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1931        self.excerpts_by_path.clear();
1932        self.paths_by_excerpt.clear();
1933        let MultiBufferSnapshot {
1934            excerpts,
1935            buffer_locators,
1936            diffs: _,
1937            diff_transforms: _,
1938            non_text_state_update_count: _,
1939            edit_count: _,
1940            is_dirty,
1941            has_deleted_file,
1942            has_conflict,
1943            has_inverted_diff,
1944            singleton: _,
1945            excerpt_ids: _,
1946            replaced_excerpts,
1947            trailing_excerpt_update_count,
1948            all_diff_hunks_expanded: _,
1949            show_deleted_hunks: _,
1950            use_extended_diff_range: _,
1951            show_headers: _,
1952        } = self.snapshot.get_mut();
1953        buffer_locators.clear();
1954        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1955        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1956        *excerpts = Default::default();
1957        *trailing_excerpt_update_count += 1;
1958        *is_dirty = false;
1959        *has_deleted_file = false;
1960        *has_conflict = false;
1961        *has_inverted_diff = false;
1962        match Arc::get_mut(replaced_excerpts) {
1963            Some(replaced_excerpts) => replaced_excerpts.clear(),
1964            None => *replaced_excerpts = Default::default(),
1965        }
1966
1967        let edits = Self::sync_diff_transforms(
1968            self.snapshot.get_mut(),
1969            vec![Edit {
1970                old: start..prev_len,
1971                new: start..start,
1972            }],
1973            DiffChangeKind::BufferEdited,
1974        );
1975        if !edits.is_empty() {
1976            self.subscriptions.publish(edits);
1977        }
1978        cx.emit(Event::Edited {
1979            edited_buffer: None,
1980            is_local: true,
1981        });
1982        cx.emit(Event::ExcerptsRemoved {
1983            ids,
1984            removed_buffer_ids,
1985        });
1986        cx.notify();
1987    }
1988
1989    #[ztracing::instrument(skip_all)]
1990    pub fn excerpts_for_buffer(
1991        &self,
1992        buffer_id: BufferId,
1993        cx: &App,
1994    ) -> Vec<(ExcerptId, Arc<BufferSnapshot>, ExcerptRange<text::Anchor>)> {
1995        let mut excerpts = Vec::new();
1996        let snapshot = self.read(cx);
1997        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1998        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1999            for locator in &**locators {
2000                cursor.seek_forward(&Some(locator), Bias::Left);
2001                if let Some(excerpt) = cursor.item()
2002                    && excerpt.locator == *locator
2003                {
2004                    excerpts.push((excerpt.id, excerpt.buffer.clone(), excerpt.range.clone()));
2005                }
2006            }
2007        }
2008
2009        excerpts
2010    }
2011
2012    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2013        let snapshot = self.read(cx);
2014        let mut excerpts = snapshot
2015            .excerpts
2016            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2017        let mut diff_transforms = snapshot
2018            .diff_transforms
2019            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2020        diff_transforms.next();
2021        let locators = snapshot
2022            .buffer_locators
2023            .get(&buffer_id)
2024            .into_iter()
2025            .flat_map(|v| &**v);
2026        let mut result = Vec::new();
2027        for locator in locators {
2028            excerpts.seek_forward(&Some(locator), Bias::Left);
2029            if let Some(excerpt) = excerpts.item()
2030                && excerpt.locator == *locator
2031            {
2032                let excerpt_start = excerpts.start().1;
2033                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2034
2035                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2036                let overshoot = excerpt_start - diff_transforms.start().0;
2037                let start = diff_transforms.start().1 + overshoot;
2038
2039                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2040                let overshoot = excerpt_end - diff_transforms.start().0;
2041                let end = diff_transforms.start().1 + overshoot;
2042
2043                result.push(start.0..end.0)
2044            }
2045        }
2046        result
2047    }
2048
2049    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2050        self.snapshot
2051            .borrow()
2052            .excerpts
2053            .iter()
2054            .map(|entry| entry.buffer_id)
2055            .collect()
2056    }
2057
2058    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2059        let snapshot = self.snapshot.borrow();
2060        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2061        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2062        ids
2063    }
2064
2065    pub fn excerpt_containing(
2066        &self,
2067        position: impl ToOffset,
2068        cx: &App,
2069    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2070        let snapshot = self.read(cx);
2071        let offset = position.to_offset(&snapshot);
2072
2073        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2074        cursor.seek(&offset);
2075        cursor
2076            .excerpt()
2077            .or_else(|| snapshot.excerpts.last())
2078            .map(|excerpt| {
2079                (
2080                    excerpt.id,
2081                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2082                    excerpt.range.context.clone(),
2083                )
2084            })
2085    }
2086
2087    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2088        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2089            self.buffer(buffer_id)
2090        } else {
2091            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2092            Some(buffer)
2093        }
2094    }
2095
2096    // If point is at the end of the buffer, the last excerpt is returned
2097    pub fn point_to_buffer_offset<T: ToOffset>(
2098        &self,
2099        point: T,
2100        cx: &App,
2101    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2102        let snapshot = self.read(cx);
2103        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2104        Some((
2105            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2106            offset,
2107        ))
2108    }
2109
2110    // If point is at the end of the buffer, the last excerpt is returned
2111    pub fn point_to_buffer_point<T: ToPoint>(
2112        &self,
2113        point: T,
2114        cx: &App,
2115    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2116        let snapshot = self.read(cx);
2117        let (buffer, point, is_main_buffer) =
2118            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2119        Some((
2120            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2121            point,
2122            is_main_buffer,
2123        ))
2124    }
2125
2126    pub fn buffer_point_to_anchor(
2127        &self,
2128        // todo(lw): We shouldn't need this?
2129        buffer: &Entity<Buffer>,
2130        point: Point,
2131        cx: &App,
2132    ) -> Option<Anchor> {
2133        let mut found = None;
2134        let snapshot = buffer.read(cx).snapshot();
2135        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2136            let start = range.context.start.to_point(&snapshot);
2137            let end = range.context.end.to_point(&snapshot);
2138            if start <= point && point < end {
2139                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2140                break;
2141            }
2142            if point < start {
2143                found = Some((start, excerpt_id));
2144            }
2145            if point > end {
2146                found = Some((end, excerpt_id));
2147            }
2148        }
2149
2150        found.map(|(point, excerpt_id)| {
2151            let text_anchor = snapshot.anchor_after(point);
2152            Anchor::in_buffer(excerpt_id, text_anchor)
2153        })
2154    }
2155
2156    pub fn buffer_anchor_to_anchor(
2157        &self,
2158        // todo(lw): We shouldn't need this?
2159        buffer: &Entity<Buffer>,
2160        anchor: text::Anchor,
2161        cx: &App,
2162    ) -> Option<Anchor> {
2163        let snapshot = buffer.read(cx).snapshot();
2164        for (excerpt_id, _, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2165            if range.context.start.cmp(&anchor, &snapshot).is_le()
2166                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2167            {
2168                return Some(Anchor::in_buffer(excerpt_id, anchor));
2169            }
2170        }
2171
2172        None
2173    }
2174
2175    pub fn merge_excerpts(
2176        &mut self,
2177        excerpt_ids: &[ExcerptId],
2178        cx: &mut Context<Self>,
2179    ) -> ExcerptId {
2180        debug_assert!(!excerpt_ids.is_empty());
2181        if excerpt_ids.len() == 1 {
2182            return excerpt_ids[0];
2183        }
2184
2185        let snapshot = self.snapshot(cx);
2186
2187        let first_range = snapshot
2188            .context_range_for_excerpt(excerpt_ids[0])
2189            .expect("first excerpt must exist");
2190        let last_range = snapshot
2191            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2192            .expect("last excerpt must exist");
2193
2194        let union_range = first_range.start..last_range.end;
2195
2196        drop(snapshot);
2197
2198        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2199        let removed = &excerpt_ids[1..];
2200        for &excerpt_id in removed {
2201            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2202                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2203                    excerpt_list.retain(|id| *id != excerpt_id);
2204                    if excerpt_list.is_empty() {
2205                        let path = path.clone();
2206                        self.excerpts_by_path.remove(&path);
2207                    }
2208                }
2209            }
2210        }
2211        self.remove_excerpts(removed.iter().copied(), cx);
2212
2213        excerpt_ids[0]
2214    }
2215
2216    pub fn remove_excerpts(
2217        &mut self,
2218        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2219        cx: &mut Context<Self>,
2220    ) {
2221        self.sync_mut(cx);
2222        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2223        if ids.is_empty() {
2224            return;
2225        }
2226        self.buffer_changed_since_sync.replace(true);
2227
2228        let mut snapshot = self.snapshot.get_mut();
2229        let mut new_excerpts = SumTree::default();
2230        let mut cursor = snapshot
2231            .excerpts
2232            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2233        let mut edits = Vec::new();
2234        let mut excerpt_ids = ids.iter().copied().peekable();
2235        let mut removed_buffer_ids = Vec::new();
2236        let mut removed_excerpts_for_buffers = HashSet::default();
2237
2238        while let Some(excerpt_id) = excerpt_ids.next() {
2239            self.paths_by_excerpt.remove(&excerpt_id);
2240            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2241            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2242            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2243
2244            if let Some(mut excerpt) = cursor.item() {
2245                if excerpt.id != excerpt_id {
2246                    continue;
2247                }
2248                let mut old_start = cursor.start().1;
2249
2250                // Skip over the removed excerpt.
2251                'remove_excerpts: loop {
2252                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2253                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2254                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2255                        if buffer_state.excerpts.is_empty() {
2256                            log::debug!(
2257                                "removing buffer and diff for buffer {}",
2258                                excerpt.buffer_id
2259                            );
2260                            self.buffers.remove(&excerpt.buffer_id);
2261                            removed_buffer_ids.push(excerpt.buffer_id);
2262                        }
2263                    }
2264                    cursor.next();
2265
2266                    // Skip over any subsequent excerpts that are also removed.
2267                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2268                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2269                        if let Some(next_excerpt) = cursor.item()
2270                            && next_excerpt.locator == *next_locator
2271                        {
2272                            excerpt_ids.next();
2273                            excerpt = next_excerpt;
2274                            continue 'remove_excerpts;
2275                        }
2276                    }
2277
2278                    break;
2279                }
2280
2281                // When removing the last excerpt, remove the trailing newline from
2282                // the previous excerpt.
2283                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2284                    old_start -= 1;
2285                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2286                }
2287
2288                // Push an edit for the removal of this run of excerpts.
2289                let old_end = cursor.start().1;
2290                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2291                edits.push(Edit {
2292                    old: old_start..old_end,
2293                    new: new_start..new_start,
2294                });
2295            }
2296        }
2297        let suffix = cursor.suffix();
2298        let changed_trailing_excerpt = suffix.is_empty();
2299        new_excerpts.append(suffix, ());
2300        drop(cursor);
2301        for buffer_id in removed_excerpts_for_buffers {
2302            match self.buffers.get(&buffer_id) {
2303                Some(buffer_state) => {
2304                    snapshot
2305                        .buffer_locators
2306                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2307                }
2308                None => {
2309                    snapshot.buffer_locators.remove(&buffer_id);
2310                }
2311            }
2312        }
2313        snapshot.excerpts = new_excerpts;
2314        for buffer_id in &removed_buffer_ids {
2315            self.diffs.remove(buffer_id);
2316            snapshot.diffs.remove(buffer_id);
2317        }
2318
2319        // Recalculate has_inverted_diff after removing diffs
2320        if !removed_buffer_ids.is_empty() {
2321            snapshot.has_inverted_diff = snapshot
2322                .diffs
2323                .iter()
2324                .any(|(_, diff)| diff.main_buffer.is_some());
2325        }
2326
2327        if changed_trailing_excerpt {
2328            snapshot.trailing_excerpt_update_count += 1;
2329        }
2330
2331        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2332        if !edits.is_empty() {
2333            self.subscriptions.publish(edits);
2334        }
2335        cx.emit(Event::Edited {
2336            edited_buffer: None,
2337            is_local: true,
2338        });
2339        cx.emit(Event::ExcerptsRemoved {
2340            ids,
2341            removed_buffer_ids,
2342        });
2343        cx.notify();
2344    }
2345
2346    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2347        &self,
2348        anchors: Anchors,
2349        cx: &mut Context<Self>,
2350    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2351        let mut error = None;
2352        let mut futures = Vec::new();
2353        for anchor in anchors {
2354            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2355                if let Some(buffer) = self.buffers.get(&buffer_id) {
2356                    buffer.buffer.update(cx, |buffer, _| {
2357                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2358                    });
2359                } else {
2360                    error = Some(anyhow!(
2361                        "buffer {buffer_id} is not part of this multi-buffer"
2362                    ));
2363                    break;
2364                }
2365            }
2366        }
2367        async move {
2368            if let Some(error) = error {
2369                Err(error)?;
2370            }
2371            for future in futures {
2372                future.await?;
2373            }
2374            Ok(())
2375        }
2376    }
2377
2378    pub fn text_anchor_for_position<T: ToOffset>(
2379        &self,
2380        position: T,
2381        cx: &App,
2382    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2383        let snapshot = self.read(cx);
2384        let anchor = snapshot.anchor_before(position);
2385        let buffer = self
2386            .buffers
2387            .get(&anchor.text_anchor.buffer_id?)?
2388            .buffer
2389            .clone();
2390        Some((buffer, anchor.text_anchor))
2391    }
2392
2393    fn on_buffer_event(
2394        &mut self,
2395        buffer: Entity<Buffer>,
2396        event: &language::BufferEvent,
2397        cx: &mut Context<Self>,
2398    ) {
2399        use language::BufferEvent;
2400        let buffer_id = buffer.read(cx).remote_id();
2401        cx.emit(match event {
2402            &BufferEvent::Edited { is_local } => Event::Edited {
2403                edited_buffer: Some(buffer),
2404                is_local,
2405            },
2406            BufferEvent::DirtyChanged => Event::DirtyChanged,
2407            BufferEvent::Saved => Event::Saved,
2408            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2409            BufferEvent::Reloaded => Event::Reloaded,
2410            BufferEvent::LanguageChanged(has_language) => {
2411                Event::LanguageChanged(buffer_id, *has_language)
2412            }
2413            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2414            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2415            BufferEvent::CapabilityChanged => {
2416                self.capability = buffer.read(cx).capability();
2417                return;
2418            }
2419            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2420        });
2421    }
2422
2423    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2424        let diff = diff.read(cx);
2425        let buffer_id = diff.buffer_id;
2426        let diff = DiffStateSnapshot {
2427            diff: diff.snapshot(cx),
2428            main_buffer: None,
2429        };
2430        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2431    }
2432
2433    fn inverted_buffer_diff_language_changed(
2434        &mut self,
2435        diff: Entity<BufferDiff>,
2436        main_buffer: Entity<language::Buffer>,
2437        cx: &mut Context<Self>,
2438    ) {
2439        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2440        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2441        let diff = diff.read(cx);
2442        let diff = DiffStateSnapshot {
2443            diff: diff.snapshot(cx),
2444            main_buffer: Some(main_buffer_snapshot),
2445        };
2446        self.snapshot
2447            .get_mut()
2448            .diffs
2449            .insert(base_text_buffer_id, diff);
2450    }
2451
2452    fn buffer_diff_changed(
2453        &mut self,
2454        diff: Entity<BufferDiff>,
2455        range: Range<text::Anchor>,
2456        cx: &mut Context<Self>,
2457    ) {
2458        self.sync_mut(cx);
2459
2460        let diff = diff.read(cx);
2461        let buffer_id = diff.buffer_id;
2462
2463        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2464            return;
2465        };
2466        let new_diff = DiffStateSnapshot {
2467            diff: diff.snapshot(cx),
2468            main_buffer: None,
2469        };
2470        let mut snapshot = self.snapshot.get_mut();
2471        let base_text_changed = snapshot
2472            .diffs
2473            .get(&buffer_id)
2474            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2475        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2476
2477        let buffer = buffer_state.buffer.read(cx);
2478        let diff_change_range = range.to_offset(buffer);
2479
2480        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2481        let edits = Self::sync_diff_transforms(
2482            &mut snapshot,
2483            excerpt_edits,
2484            DiffChangeKind::DiffUpdated {
2485                base_changed: base_text_changed,
2486            },
2487        );
2488        if !edits.is_empty() {
2489            self.subscriptions.publish(edits);
2490        }
2491        cx.emit(Event::Edited {
2492            edited_buffer: None,
2493            is_local: true,
2494        });
2495    }
2496
2497    fn inverted_buffer_diff_changed(
2498        &mut self,
2499        diff: Entity<BufferDiff>,
2500        main_buffer: Entity<language::Buffer>,
2501        diff_change_range: Option<Range<usize>>,
2502        cx: &mut Context<Self>,
2503    ) {
2504        self.sync_mut(cx);
2505
2506        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2507        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2508            return;
2509        };
2510
2511        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2512        let diff = diff.read(cx);
2513        let new_diff = DiffStateSnapshot {
2514            diff: diff.snapshot(cx),
2515            main_buffer: Some(main_buffer_snapshot),
2516        };
2517        let mut snapshot = self.snapshot.get_mut();
2518        snapshot
2519            .diffs
2520            .insert_or_replace(base_text_buffer_id, new_diff);
2521
2522        let Some(diff_change_range) = diff_change_range else {
2523            return;
2524        };
2525
2526        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2527        let edits = Self::sync_diff_transforms(
2528            &mut snapshot,
2529            excerpt_edits,
2530            DiffChangeKind::DiffUpdated {
2531                // We don't read this field for inverted diffs.
2532                base_changed: false,
2533            },
2534        );
2535        if !edits.is_empty() {
2536            self.subscriptions.publish(edits);
2537        }
2538        cx.emit(Event::Edited {
2539            edited_buffer: None,
2540            is_local: true,
2541        });
2542    }
2543
2544    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2545        self.buffers.values().map(|state| state.buffer.clone())
2546    }
2547
2548    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2549        self.all_buffers_iter().collect()
2550    }
2551
2552    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2553        self.buffers.keys().copied()
2554    }
2555
2556    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2557        self.all_buffer_ids_iter().collect()
2558    }
2559
2560    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2561        self.buffers
2562            .get(&buffer_id)
2563            .map(|state| state.buffer.clone())
2564    }
2565
2566    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2567        self.point_to_buffer_offset(point, cx)
2568            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2569    }
2570
2571    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2572        let buffer_id = self
2573            .snapshot
2574            .borrow()
2575            .excerpts
2576            .first()
2577            .map(|excerpt| excerpt.buffer.remote_id());
2578        buffer_id
2579            .and_then(|buffer_id| self.buffer(buffer_id))
2580            .map(|buffer| LanguageSettings::for_buffer(&buffer.read(cx), cx))
2581            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2582    }
2583
2584    pub fn language_settings_at<'a, T: ToOffset>(
2585        &'a self,
2586        point: T,
2587        cx: &'a App,
2588    ) -> Cow<'a, LanguageSettings> {
2589        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2590            LanguageSettings::for_buffer_at(buffer.read(cx), offset, cx)
2591        } else {
2592            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
2593        }
2594    }
2595
2596    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2597        self.buffers.values().for_each(|state| f(&state.buffer))
2598    }
2599
2600    pub fn explicit_title(&self) -> Option<&str> {
2601        self.title.as_deref()
2602    }
2603
2604    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2605        if let Some(title) = self.title.as_ref() {
2606            return title.into();
2607        }
2608
2609        if let Some(buffer) = self.as_singleton() {
2610            let buffer = buffer.read(cx);
2611
2612            if let Some(file) = buffer.file() {
2613                return file.file_name(cx).into();
2614            }
2615
2616            if let Some(title) = self.buffer_content_title(buffer) {
2617                return title;
2618            }
2619        };
2620
2621        "untitled".into()
2622    }
2623
2624    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2625        let mut is_leading_whitespace = true;
2626        let mut count = 0;
2627        let mut prev_was_space = false;
2628        let mut title = String::new();
2629
2630        for ch in buffer.snapshot().chars() {
2631            if is_leading_whitespace && ch.is_whitespace() {
2632                continue;
2633            }
2634
2635            is_leading_whitespace = false;
2636
2637            if ch == '\n' || count >= 40 {
2638                break;
2639            }
2640
2641            if ch.is_whitespace() {
2642                if !prev_was_space {
2643                    title.push(' ');
2644                    count += 1;
2645                    prev_was_space = true;
2646                }
2647            } else {
2648                title.push(ch);
2649                count += 1;
2650                prev_was_space = false;
2651            }
2652        }
2653
2654        let title = title.trim_end().to_string();
2655
2656        if title.is_empty() {
2657            return None;
2658        }
2659
2660        Some(title.into())
2661    }
2662
2663    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2664        self.title = Some(title);
2665        cx.notify();
2666    }
2667
2668    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2669    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2670        for buffer_state in self.buffers.values() {
2671            buffer_state
2672                .buffer
2673                .update(cx, |buffer, _cx| buffer.refresh_preview());
2674        }
2675    }
2676
2677    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2678    pub fn preserve_preview(&self, cx: &App) -> bool {
2679        self.buffers
2680            .values()
2681            .all(|state| state.buffer.read(cx).preserve_preview())
2682    }
2683
2684    #[cfg(any(test, feature = "test-support"))]
2685    pub fn is_parsing(&self, cx: &App) -> bool {
2686        self.as_singleton().unwrap().read(cx).is_parsing()
2687    }
2688
2689    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2690        let buffer_id = diff.read(cx).buffer_id;
2691
2692        if let Some(existing_diff) = self.diff_for(buffer_id)
2693            && diff.entity_id() == existing_diff.entity_id()
2694        {
2695            return;
2696        }
2697
2698        self.buffer_diff_changed(
2699            diff.clone(),
2700            text::Anchor::min_max_range_for_buffer(buffer_id),
2701            cx,
2702        );
2703        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2704    }
2705
2706    pub fn add_inverted_diff(
2707        &mut self,
2708        diff: Entity<BufferDiff>,
2709        main_buffer: Entity<language::Buffer>,
2710        cx: &mut Context<Self>,
2711    ) {
2712        let snapshot = diff.read(cx).base_text(cx);
2713        let base_text_buffer_id = snapshot.remote_id();
2714        let diff_change_range = 0..snapshot.len();
2715        self.snapshot.get_mut().has_inverted_diff = true;
2716        self.inverted_buffer_diff_changed(
2717            diff.clone(),
2718            main_buffer.clone(),
2719            Some(diff_change_range),
2720            cx,
2721        );
2722        self.diffs.insert(
2723            base_text_buffer_id,
2724            DiffState::new_inverted(diff, main_buffer, cx),
2725        );
2726    }
2727
2728    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2729        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2730    }
2731
2732    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2733        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2734    }
2735
2736    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2737        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2738    }
2739
2740    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2741        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2742        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2743    }
2744
2745    pub fn all_diff_hunks_expanded(&self) -> bool {
2746        self.snapshot.borrow().all_diff_hunks_expanded
2747    }
2748
2749    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2750        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2751        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2752    }
2753
2754    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2755        self.snapshot.get_mut().show_deleted_hunks = show;
2756
2757        self.sync_mut(cx);
2758
2759        let old_len = self.snapshot.borrow().len();
2760
2761        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2762        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2763
2764        let new_len = self.snapshot.borrow().len();
2765
2766        self.subscriptions.publish(vec![Edit {
2767            old: MultiBufferOffset(0)..old_len,
2768            new: MultiBufferOffset(0)..new_len,
2769        }]);
2770
2771        cx.emit(Event::DiffHunksToggled);
2772        cx.emit(Event::Edited {
2773            edited_buffer: None,
2774            is_local: true,
2775        });
2776    }
2777
2778    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2779        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2780    }
2781
2782    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2783        self.read(cx)
2784            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2785            .nth(1)
2786            .is_some()
2787    }
2788
2789    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2790        let snapshot = self.read(cx);
2791        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2792        let offset_range = range.to_offset(&snapshot);
2793        cursor.seek(&offset_range.start, Bias::Left);
2794        while let Some(item) = cursor.item() {
2795            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2796                break;
2797            }
2798            if item.hunk_info().is_some() {
2799                return true;
2800            }
2801            cursor.next();
2802        }
2803        false
2804    }
2805
2806    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2807        let snapshot = self.read(cx);
2808        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2809        for range in ranges {
2810            let range = range.to_point(&snapshot);
2811            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2812            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2813                .min(snapshot.len());
2814            cursor.seek(&start, Bias::Right);
2815            while let Some(item) = cursor.item() {
2816                if *cursor.start() >= end {
2817                    break;
2818                }
2819                if item.hunk_info().is_some() {
2820                    return true;
2821                }
2822                cursor.next();
2823            }
2824        }
2825        false
2826    }
2827
2828    pub fn expand_or_collapse_diff_hunks_inner(
2829        &mut self,
2830        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2831        expand: bool,
2832        cx: &mut Context<Self>,
2833    ) -> Vec<Edit<MultiBufferOffset>> {
2834        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2835            return Vec::new();
2836        }
2837        self.sync_mut(cx);
2838        let mut snapshot = self.snapshot.get_mut();
2839        let mut excerpt_edits = Vec::new();
2840        let mut last_hunk_row = None;
2841        for (range, end_excerpt_id) in ranges {
2842            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2843                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2844                    continue;
2845                }
2846                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2847                    continue;
2848                }
2849                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2850                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2851                let start = snapshot.excerpt_offset_for_anchor(&start);
2852                let end = snapshot.excerpt_offset_for_anchor(&end);
2853                last_hunk_row = Some(diff_hunk.row_range.start);
2854                excerpt_edits.push(text::Edit {
2855                    old: start..end,
2856                    new: start..end,
2857                });
2858            }
2859        }
2860
2861        Self::sync_diff_transforms(
2862            &mut snapshot,
2863            excerpt_edits,
2864            DiffChangeKind::ExpandOrCollapseHunks { expand },
2865        )
2866    }
2867
2868    pub fn expand_or_collapse_diff_hunks(
2869        &mut self,
2870        ranges: Vec<Range<Anchor>>,
2871        expand: bool,
2872        cx: &mut Context<Self>,
2873    ) {
2874        let snapshot = self.snapshot.borrow().clone();
2875        let ranges = ranges.iter().map(move |range| {
2876            let end_excerpt_id = range.end.excerpt_id;
2877            let range = range.to_point(&snapshot);
2878            let mut peek_end = range.end;
2879            if range.end.row < snapshot.max_row().0 {
2880                peek_end = Point::new(range.end.row + 1, 0);
2881            };
2882            (range.start..peek_end, end_excerpt_id)
2883        });
2884        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2885        if !edits.is_empty() {
2886            self.subscriptions.publish(edits);
2887        }
2888        cx.emit(Event::DiffHunksToggled);
2889        cx.emit(Event::Edited {
2890            edited_buffer: None,
2891            is_local: true,
2892        });
2893    }
2894
2895    pub fn resize_excerpt(
2896        &mut self,
2897        id: ExcerptId,
2898        range: Range<text::Anchor>,
2899        cx: &mut Context<Self>,
2900    ) {
2901        self.sync_mut(cx);
2902
2903        let mut snapshot = self.snapshot.get_mut();
2904        let locator = snapshot.excerpt_locator_for_id(id);
2905        let mut new_excerpts = SumTree::default();
2906        let mut cursor = snapshot
2907            .excerpts
2908            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2909        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2910
2911        let prefix = cursor.slice(&Some(locator), Bias::Left);
2912        new_excerpts.append(prefix, ());
2913
2914        let mut excerpt = cursor.item().unwrap().clone();
2915        let old_text_len = excerpt.text_summary.len;
2916
2917        excerpt.range.context.start = range.start;
2918        excerpt.range.context.end = range.end;
2919        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2920
2921        excerpt.text_summary = excerpt
2922            .buffer
2923            .text_summary_for_range(excerpt.range.context.clone());
2924
2925        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2926        let old_start_offset = cursor.start().1;
2927        let new_text_len = excerpt.text_summary.len;
2928        let edit = Edit {
2929            old: old_start_offset..old_start_offset + old_text_len,
2930            new: new_start_offset..new_start_offset + new_text_len,
2931        };
2932
2933        if let Some(last_edit) = edits.last_mut() {
2934            if last_edit.old.end == edit.old.start {
2935                last_edit.old.end = edit.old.end;
2936                last_edit.new.end = edit.new.end;
2937            } else {
2938                edits.push(edit);
2939            }
2940        } else {
2941            edits.push(edit);
2942        }
2943
2944        new_excerpts.push(excerpt, ());
2945
2946        cursor.next();
2947
2948        new_excerpts.append(cursor.suffix(), ());
2949
2950        drop(cursor);
2951        snapshot.excerpts = new_excerpts;
2952
2953        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2954        if !edits.is_empty() {
2955            self.subscriptions.publish(edits);
2956        }
2957        cx.emit(Event::Edited {
2958            edited_buffer: None,
2959            is_local: true,
2960        });
2961        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2962        cx.notify();
2963    }
2964
2965    pub fn expand_excerpts(
2966        &mut self,
2967        ids: impl IntoIterator<Item = ExcerptId>,
2968        line_count: u32,
2969        direction: ExpandExcerptDirection,
2970        cx: &mut Context<Self>,
2971    ) {
2972        if line_count == 0 {
2973            return;
2974        }
2975        self.sync_mut(cx);
2976        if !self.excerpts_by_path.is_empty() {
2977            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2978            return;
2979        }
2980        let mut snapshot = self.snapshot.get_mut();
2981
2982        let ids = ids.into_iter().collect::<Vec<_>>();
2983        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2984        let mut new_excerpts = SumTree::default();
2985        let mut cursor = snapshot
2986            .excerpts
2987            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2988        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2989
2990        for locator in &locators {
2991            let prefix = cursor.slice(&Some(locator), Bias::Left);
2992            new_excerpts.append(prefix, ());
2993
2994            let mut excerpt = cursor.item().unwrap().clone();
2995            let old_text_len = excerpt.text_summary.len;
2996
2997            let up_line_count = if direction.should_expand_up() {
2998                line_count
2999            } else {
3000                0
3001            };
3002
3003            let start_row = excerpt
3004                .range
3005                .context
3006                .start
3007                .to_point(&excerpt.buffer)
3008                .row
3009                .saturating_sub(up_line_count);
3010            let start_point = Point::new(start_row, 0);
3011            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3012
3013            let down_line_count = if direction.should_expand_down() {
3014                line_count
3015            } else {
3016                0
3017            };
3018
3019            let mut end_point = excerpt.buffer.clip_point(
3020                excerpt.range.context.end.to_point(&excerpt.buffer)
3021                    + Point::new(down_line_count, 0),
3022                Bias::Left,
3023            );
3024            end_point.column = excerpt.buffer.line_len(end_point.row);
3025            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3026            excerpt.max_buffer_row = end_point.row;
3027
3028            excerpt.text_summary = excerpt
3029                .buffer
3030                .text_summary_for_range(excerpt.range.context.clone());
3031
3032            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3033            let old_start_offset = cursor.start().1;
3034            let new_text_len = excerpt.text_summary.len;
3035            let edit = Edit {
3036                old: old_start_offset..old_start_offset + old_text_len,
3037                new: new_start_offset..new_start_offset + new_text_len,
3038            };
3039
3040            if let Some(last_edit) = edits.last_mut() {
3041                if last_edit.old.end == edit.old.start {
3042                    last_edit.old.end = edit.old.end;
3043                    last_edit.new.end = edit.new.end;
3044                } else {
3045                    edits.push(edit);
3046                }
3047            } else {
3048                edits.push(edit);
3049            }
3050
3051            new_excerpts.push(excerpt, ());
3052
3053            cursor.next();
3054        }
3055
3056        new_excerpts.append(cursor.suffix(), ());
3057
3058        drop(cursor);
3059        snapshot.excerpts = new_excerpts;
3060
3061        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3062        if !edits.is_empty() {
3063            self.subscriptions.publish(edits);
3064        }
3065        cx.emit(Event::Edited {
3066            edited_buffer: None,
3067            is_local: true,
3068        });
3069        cx.emit(Event::ExcerptsExpanded { ids });
3070        cx.notify();
3071    }
3072
3073    #[ztracing::instrument(skip_all)]
3074    fn sync(&self, cx: &App) {
3075        let changed = self.buffer_changed_since_sync.replace(false);
3076        if !changed {
3077            return;
3078        }
3079        let edits = Self::sync_from_buffer_changes(
3080            &mut self.snapshot.borrow_mut(),
3081            &self.buffers,
3082            &self.diffs,
3083            cx,
3084        );
3085        if !edits.is_empty() {
3086            self.subscriptions.publish(edits);
3087        }
3088    }
3089
3090    fn sync_mut(&mut self, cx: &App) {
3091        let changed = self.buffer_changed_since_sync.replace(false);
3092        if !changed {
3093            return;
3094        }
3095        let edits =
3096            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3097
3098        if !edits.is_empty() {
3099            self.subscriptions.publish(edits);
3100        }
3101    }
3102
3103    fn sync_from_buffer_changes(
3104        snapshot: &mut MultiBufferSnapshot,
3105        buffers: &BTreeMap<BufferId, BufferState>,
3106        diffs: &HashMap<BufferId, DiffState>,
3107        cx: &App,
3108    ) -> Vec<Edit<MultiBufferOffset>> {
3109        let MultiBufferSnapshot {
3110            excerpts,
3111            buffer_locators: _,
3112            diffs: buffer_diff,
3113            diff_transforms: _,
3114            non_text_state_update_count,
3115            edit_count,
3116            is_dirty,
3117            has_deleted_file,
3118            has_conflict,
3119            has_inverted_diff: _,
3120            singleton: _,
3121            excerpt_ids: _,
3122            replaced_excerpts: _,
3123            trailing_excerpt_update_count: _,
3124            all_diff_hunks_expanded: _,
3125            show_deleted_hunks: _,
3126            use_extended_diff_range: _,
3127            show_headers: _,
3128        } = snapshot;
3129        *is_dirty = false;
3130        *has_deleted_file = false;
3131        *has_conflict = false;
3132
3133        if !diffs.is_empty() {
3134            let mut diffs_to_add = Vec::new();
3135            for (id, diff) in diffs {
3136                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3137                // and use the diff hunk base text ranges to compute diff transforms.
3138                // Those base text ranges are usize, so make sure if the base text changed
3139                // we also update the diff snapshot so that we don't use stale offsets
3140                if buffer_diff.get(id).is_none_or(|existing_diff| {
3141                    if existing_diff.main_buffer.is_none() {
3142                        return false;
3143                    }
3144                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3145                    base_text.remote_id() != existing_diff.base_text().remote_id()
3146                        || base_text
3147                            .version()
3148                            .changed_since(existing_diff.base_text().version())
3149                }) {
3150                    if diffs_to_add.capacity() == 0 {
3151                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3152                        // meaning re-allocations will be fairly expensive
3153                        diffs_to_add.reserve(diffs.len());
3154                    }
3155                    diffs_to_add.push((*id, diff.snapshot(cx)));
3156                }
3157            }
3158            buffer_diff.extend(diffs_to_add);
3159        }
3160
3161        let mut excerpts_to_edit = Vec::new();
3162        let mut non_text_state_updated = false;
3163        let mut edited = false;
3164        for buffer_state in buffers.values() {
3165            let buffer = buffer_state.buffer.read(cx);
3166            let version = buffer.version();
3167            let non_text_state_update_count = buffer.non_text_state_update_count();
3168
3169            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3170            let buffer_non_text_state_updated =
3171                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3172            if buffer_edited || buffer_non_text_state_updated {
3173                *buffer_state.last_version.borrow_mut() = version;
3174                buffer_state
3175                    .last_non_text_state_update_count
3176                    .set(non_text_state_update_count);
3177                excerpts_to_edit.extend(
3178                    buffer_state
3179                        .excerpts
3180                        .iter()
3181                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3182                );
3183            }
3184
3185            edited |= buffer_edited;
3186            non_text_state_updated |= buffer_non_text_state_updated;
3187            *is_dirty |= buffer.is_dirty();
3188            *has_deleted_file |= buffer
3189                .file()
3190                .is_some_and(|file| file.disk_state().is_deleted());
3191            *has_conflict |= buffer.has_conflict();
3192        }
3193        if edited {
3194            *edit_count += 1;
3195        }
3196        if non_text_state_updated {
3197            *non_text_state_update_count += 1;
3198        }
3199
3200        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3201
3202        let mut edits = Vec::new();
3203        let mut new_excerpts = SumTree::default();
3204        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3205
3206        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3207            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3208            let old_excerpt = cursor.item().unwrap();
3209            let buffer = buffer.read(cx);
3210            let buffer_id = buffer.remote_id();
3211            let mut new_excerpt;
3212            if buffer_edited {
3213                edits.extend(
3214                    buffer
3215                        .edits_since_in_range::<usize>(
3216                            old_excerpt.buffer.version(),
3217                            old_excerpt.range.context.clone(),
3218                        )
3219                        .map(|edit| {
3220                            let excerpt_old_start = cursor.start().1;
3221                            let excerpt_new_start =
3222                                ExcerptDimension(new_excerpts.summary().text.len);
3223                            let old_start = excerpt_old_start + edit.old.start;
3224                            let old_end = excerpt_old_start + edit.old.end;
3225                            let new_start = excerpt_new_start + edit.new.start;
3226                            let new_end = excerpt_new_start + edit.new.end;
3227                            Edit {
3228                                old: old_start..old_end,
3229                                new: new_start..new_end,
3230                            }
3231                        }),
3232                );
3233
3234                new_excerpt = Excerpt::new(
3235                    old_excerpt.id,
3236                    locator.clone(),
3237                    buffer_id,
3238                    Arc::new(buffer.snapshot()),
3239                    old_excerpt.range.clone(),
3240                    old_excerpt.has_trailing_newline,
3241                );
3242            } else {
3243                new_excerpt = old_excerpt.clone();
3244                new_excerpt.buffer = Arc::new(buffer.snapshot());
3245            }
3246
3247            new_excerpts.push(new_excerpt, ());
3248            cursor.next();
3249        }
3250        new_excerpts.append(cursor.suffix(), ());
3251
3252        drop(cursor);
3253        *excerpts = new_excerpts;
3254
3255        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3256    }
3257
3258    fn sync_diff_transforms(
3259        snapshot: &mut MultiBufferSnapshot,
3260        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3261        change_kind: DiffChangeKind,
3262    ) -> Vec<Edit<MultiBufferOffset>> {
3263        if excerpt_edits.is_empty() {
3264            return vec![];
3265        }
3266
3267        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3268        let mut old_diff_transforms = snapshot
3269            .diff_transforms
3270            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3271        let mut new_diff_transforms = SumTree::default();
3272        let mut old_expanded_hunks = HashSet::default();
3273        let mut output_edits = Vec::new();
3274        let mut output_delta = 0_isize;
3275        let mut at_transform_boundary = true;
3276        let mut end_of_current_insert = None;
3277
3278        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3279        while let Some(edit) = excerpt_edits.next() {
3280            excerpts.seek_forward(&edit.new.start, Bias::Right);
3281            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3282                excerpts.prev();
3283            }
3284
3285            // Keep any transforms that are before the edit.
3286            if at_transform_boundary {
3287                at_transform_boundary = false;
3288                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3289                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3290                if let Some(transform) = old_diff_transforms.item()
3291                    && old_diff_transforms.end().0 == edit.old.start
3292                    && old_diff_transforms.start().0 < edit.old.start
3293                {
3294                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3295                    old_diff_transforms.next();
3296                }
3297            }
3298
3299            // Compute the start of the edit in output coordinates.
3300            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3301            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3302            let edit_new_start =
3303                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3304
3305            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3306                &edit,
3307                &mut excerpts,
3308                &mut old_diff_transforms,
3309                &mut new_diff_transforms,
3310                &mut end_of_current_insert,
3311                &mut old_expanded_hunks,
3312                snapshot,
3313                change_kind,
3314            );
3315
3316            // Compute the end of the edit in output coordinates.
3317            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3318            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3319            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3320            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3321            let output_edit = Edit {
3322                old: edit_old_start..edit_old_end,
3323                new: edit_new_start..edit_new_end,
3324            };
3325
3326            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3327            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3328            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3329                output_edits.push(output_edit);
3330            }
3331
3332            // If this is the last edit that intersects the current diff transform,
3333            // then recreate the content up to the end of this transform, to prepare
3334            // for reusing additional slices of the old transforms.
3335            if excerpt_edits
3336                .peek()
3337                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3338            {
3339                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3340                    && match old_diff_transforms.item() {
3341                        Some(DiffTransform::BufferContent {
3342                            inserted_hunk_info: Some(hunk),
3343                            ..
3344                        }) => excerpts.item().is_some_and(|excerpt| {
3345                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3346                                && diff.main_buffer.is_some()
3347                            {
3348                                return true;
3349                            }
3350                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3351                        }),
3352                        _ => true,
3353                    };
3354
3355                let mut excerpt_offset = edit.new.end;
3356                if !keep_next_old_transform {
3357                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3358                    old_diff_transforms.next();
3359                }
3360
3361                old_expanded_hunks.clear();
3362                Self::push_buffer_content_transform(
3363                    snapshot,
3364                    &mut new_diff_transforms,
3365                    excerpt_offset,
3366                    end_of_current_insert,
3367                );
3368                at_transform_boundary = true;
3369            }
3370        }
3371
3372        // Keep any transforms that are after the last edit.
3373        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3374
3375        // Ensure there's always at least one buffer content transform.
3376        if new_diff_transforms.is_empty() {
3377            new_diff_transforms.push(
3378                DiffTransform::BufferContent {
3379                    summary: Default::default(),
3380                    inserted_hunk_info: None,
3381                },
3382                (),
3383            );
3384        }
3385
3386        drop(old_diff_transforms);
3387        drop(excerpts);
3388        snapshot.diff_transforms = new_diff_transforms;
3389        snapshot.edit_count += 1;
3390
3391        #[cfg(any(test, feature = "test-support"))]
3392        snapshot.check_invariants();
3393        output_edits
3394    }
3395
3396    fn recompute_diff_transforms_for_edit(
3397        edit: &Edit<ExcerptOffset>,
3398        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3399        old_diff_transforms: &mut Cursor<
3400            DiffTransform,
3401            Dimensions<ExcerptOffset, MultiBufferOffset>,
3402        >,
3403        new_diff_transforms: &mut SumTree<DiffTransform>,
3404        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3405        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3406        snapshot: &MultiBufferSnapshot,
3407        change_kind: DiffChangeKind,
3408    ) -> bool {
3409        log::trace!(
3410            "recomputing diff transform for edit {:?} => {:?}",
3411            edit.old.start..edit.old.end,
3412            edit.new.start..edit.new.end
3413        );
3414
3415        // Record which hunks were previously expanded.
3416        while let Some(item) = old_diff_transforms.item() {
3417            if let Some(hunk_info) = item.hunk_info() {
3418                log::trace!(
3419                    "previously expanded hunk at {:?}",
3420                    old_diff_transforms.start()
3421                );
3422                old_expanded_hunks.insert(hunk_info);
3423            }
3424            if old_diff_transforms.end().0 > edit.old.end {
3425                break;
3426            }
3427            old_diff_transforms.next();
3428        }
3429
3430        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3431        // For inverted diffs, hunks are always shown, so we can't skip this.
3432        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3433        if old_expanded_hunks.is_empty()
3434            && change_kind == DiffChangeKind::BufferEdited
3435            && !all_diff_hunks_expanded
3436            && !snapshot.has_inverted_diff
3437        {
3438            return false;
3439        }
3440
3441        // Visit each excerpt that intersects the edit.
3442        let mut did_expand_hunks = false;
3443        while let Some(excerpt) = excerpts.item() {
3444            // Recompute the expanded hunks in the portion of the excerpt that
3445            // intersects the edit.
3446            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3447                let buffer = &excerpt.buffer;
3448                let excerpt_start = *excerpts.start();
3449                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3450                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3451                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3452                let edit_buffer_start =
3453                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3454                let edit_buffer_end =
3455                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3456                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3457
3458                if let Some(main_buffer) = &diff.main_buffer {
3459                    for hunk in diff.hunks_intersecting_base_text_range(
3460                        edit_buffer_start..edit_buffer_end,
3461                        main_buffer,
3462                    ) {
3463                        did_expand_hunks = true;
3464                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3465                        if hunk_buffer_range.start < excerpt_buffer_start {
3466                            log::trace!("skipping hunk that starts before excerpt");
3467                            continue;
3468                        }
3469                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3470                        let hunk_excerpt_start = excerpt_start
3471                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3472                        let hunk_excerpt_end = excerpt_end
3473                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3474                        Self::push_buffer_content_transform(
3475                            snapshot,
3476                            new_diff_transforms,
3477                            hunk_excerpt_start,
3478                            *end_of_current_insert,
3479                        );
3480                        if !hunk_buffer_range.is_empty() {
3481                            let hunk_info = DiffTransformHunkInfo {
3482                                excerpt_id: excerpt.id,
3483                                hunk_start_anchor: hunk.buffer_range.start,
3484                                hunk_secondary_status: hunk.secondary_status,
3485                                is_logically_deleted: true,
3486                            };
3487                            *end_of_current_insert =
3488                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3489                        }
3490                    }
3491                } else {
3492                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3493                        ..buffer.anchor_after(edit_buffer_end);
3494                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3495                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3496                            continue;
3497                        }
3498
3499                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3500                        if hunk_buffer_range.start < excerpt_buffer_start {
3501                            log::trace!("skipping hunk that starts before excerpt");
3502                            continue;
3503                        }
3504
3505                        let hunk_info = DiffTransformHunkInfo {
3506                            excerpt_id: excerpt.id,
3507                            hunk_start_anchor: hunk.buffer_range.start,
3508                            hunk_secondary_status: hunk.secondary_status,
3509                            is_logically_deleted: false,
3510                        };
3511
3512                        let hunk_excerpt_start = excerpt_start
3513                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3514                        let hunk_excerpt_end = excerpt_end
3515                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3516
3517                        Self::push_buffer_content_transform(
3518                            snapshot,
3519                            new_diff_transforms,
3520                            hunk_excerpt_start,
3521                            *end_of_current_insert,
3522                        );
3523
3524                        // For every existing hunk, determine if it was previously expanded
3525                        // and if it should currently be expanded.
3526                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3527                        let should_expand_hunk = match &change_kind {
3528                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3529                                was_previously_expanded || all_diff_hunks_expanded
3530                            }
3531                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3532                                let intersects = hunk_buffer_range.is_empty()
3533                                    || hunk_buffer_range.end > edit_buffer_start;
3534                                if *expand {
3535                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3536                                } else {
3537                                    !intersects
3538                                        && (was_previously_expanded || all_diff_hunks_expanded)
3539                                }
3540                            }
3541                            _ => was_previously_expanded || all_diff_hunks_expanded,
3542                        };
3543
3544                        if should_expand_hunk {
3545                            did_expand_hunks = true;
3546                            log::trace!(
3547                                "expanding hunk {:?}, excerpt:{:?}",
3548                                hunk_excerpt_start..hunk_excerpt_end,
3549                                excerpt.id
3550                            );
3551
3552                            if !hunk.diff_base_byte_range.is_empty()
3553                                && hunk_buffer_range.start >= edit_buffer_start
3554                                && hunk_buffer_range.start <= excerpt_buffer_end
3555                                && snapshot.show_deleted_hunks
3556                            {
3557                                let base_text = diff.base_text();
3558                                let mut text_cursor =
3559                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3560                                let mut base_text_summary = text_cursor
3561                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3562
3563                                let mut has_trailing_newline = false;
3564                                if base_text_summary.last_line_chars > 0 {
3565                                    base_text_summary += TextSummary::newline();
3566                                    has_trailing_newline = true;
3567                                }
3568
3569                                new_diff_transforms.push(
3570                                    DiffTransform::DeletedHunk {
3571                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3572                                        summary: base_text_summary,
3573                                        buffer_id: excerpt.buffer_id,
3574                                        hunk_info,
3575                                        has_trailing_newline,
3576                                    },
3577                                    (),
3578                                );
3579                            }
3580
3581                            if !hunk_buffer_range.is_empty() {
3582                                *end_of_current_insert =
3583                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3584                            }
3585                        }
3586                    }
3587                }
3588            }
3589
3590            if excerpts.end() <= edit.new.end {
3591                excerpts.next();
3592            } else {
3593                break;
3594            }
3595        }
3596
3597        did_expand_hunks || !old_expanded_hunks.is_empty()
3598    }
3599
3600    fn append_diff_transforms(
3601        new_transforms: &mut SumTree<DiffTransform>,
3602        subtree: SumTree<DiffTransform>,
3603    ) {
3604        if let Some(DiffTransform::BufferContent {
3605            inserted_hunk_info,
3606            summary,
3607        }) = subtree.first()
3608            && Self::extend_last_buffer_content_transform(
3609                new_transforms,
3610                *inserted_hunk_info,
3611                *summary,
3612            )
3613        {
3614            let mut cursor = subtree.cursor::<()>(());
3615            cursor.next();
3616            cursor.next();
3617            new_transforms.append(cursor.suffix(), ());
3618            return;
3619        }
3620        new_transforms.append(subtree, ());
3621    }
3622
3623    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3624        if let DiffTransform::BufferContent {
3625            inserted_hunk_info: inserted_hunk_anchor,
3626            summary,
3627        } = transform
3628            && Self::extend_last_buffer_content_transform(
3629                new_transforms,
3630                inserted_hunk_anchor,
3631                summary,
3632            )
3633        {
3634            return;
3635        }
3636        new_transforms.push(transform, ());
3637    }
3638
3639    fn push_buffer_content_transform(
3640        old_snapshot: &MultiBufferSnapshot,
3641        new_transforms: &mut SumTree<DiffTransform>,
3642        end_offset: ExcerptOffset,
3643        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3644    ) {
3645        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3646            (end_offset.min(insertion_end_offset), Some(hunk_info))
3647        });
3648        let unchanged_region = [(end_offset, None)];
3649
3650        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3651        {
3652            let start_offset = new_transforms.summary().excerpt_len();
3653            if end_offset <= start_offset {
3654                continue;
3655            }
3656            let summary_to_add = old_snapshot
3657                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3658
3659            if !Self::extend_last_buffer_content_transform(
3660                new_transforms,
3661                inserted_hunk_info,
3662                summary_to_add,
3663            ) {
3664                new_transforms.push(
3665                    DiffTransform::BufferContent {
3666                        summary: summary_to_add,
3667                        inserted_hunk_info,
3668                    },
3669                    (),
3670                )
3671            }
3672        }
3673    }
3674
3675    fn extend_last_buffer_content_transform(
3676        new_transforms: &mut SumTree<DiffTransform>,
3677        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3678        summary_to_add: MBTextSummary,
3679    ) -> bool {
3680        let mut did_extend = false;
3681        new_transforms.update_last(
3682            |last_transform| {
3683                if let DiffTransform::BufferContent {
3684                    summary,
3685                    inserted_hunk_info: inserted_hunk_anchor,
3686                } = last_transform
3687                    && *inserted_hunk_anchor == new_inserted_hunk_info
3688                {
3689                    *summary += summary_to_add;
3690                    did_extend = true;
3691                }
3692            },
3693            (),
3694        );
3695        did_extend
3696    }
3697
3698    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3699        let snapshot = self.snapshot(cx);
3700        let excerpt_id = range.end.excerpt_id;
3701        let point_range = range.to_point(&snapshot);
3702        let expand = !self.single_hunk_is_expanded(range, cx);
3703        let edits =
3704            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3705        if !edits.is_empty() {
3706            self.subscriptions.publish(edits);
3707        }
3708        cx.emit(Event::DiffHunksToggled);
3709        cx.emit(Event::Edited {
3710            edited_buffer: None,
3711            is_local: true,
3712        });
3713    }
3714}
3715
3716fn build_excerpt_ranges(
3717    ranges: impl IntoIterator<Item = Range<Point>>,
3718    context_line_count: u32,
3719    buffer_snapshot: &BufferSnapshot,
3720) -> Vec<ExcerptRange<Point>> {
3721    ranges
3722        .into_iter()
3723        .map(|range| {
3724            let start_row = range.start.row.saturating_sub(context_line_count);
3725            let start = Point::new(start_row, 0);
3726            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3727            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3728            ExcerptRange {
3729                context: start..end,
3730                primary: range,
3731            }
3732        })
3733        .collect()
3734}
3735
3736#[cfg(any(test, feature = "test-support"))]
3737impl MultiBuffer {
3738    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3739        let buffer = cx.new(|cx| Buffer::local(text, cx));
3740        cx.new(|cx| Self::singleton(buffer, cx))
3741    }
3742
3743    pub fn build_multi<const COUNT: usize>(
3744        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3745        cx: &mut gpui::App,
3746    ) -> Entity<Self> {
3747        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3748        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3749            let buffer = cx.new(|cx| Buffer::local(text, cx));
3750            let snapshot = buffer.read(cx).snapshot();
3751            let excerpt_ranges = ranges
3752                .into_iter()
3753                .map(ExcerptRange::new)
3754                .collect::<Vec<_>>();
3755            multi.update(cx, |multi, cx| {
3756                multi.set_excerpt_ranges_for_path(
3757                    PathKey::sorted(ix as u64),
3758                    buffer,
3759                    &snapshot,
3760                    excerpt_ranges,
3761                    cx,
3762                )
3763            });
3764        }
3765
3766        multi
3767    }
3768
3769    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3770        cx.new(|cx| Self::singleton(buffer, cx))
3771    }
3772
3773    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3774        cx.new(|cx| {
3775            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3776            let mutation_count = rng.random_range(1..=5);
3777            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3778            multibuffer
3779        })
3780    }
3781
3782    pub fn randomly_edit(
3783        &mut self,
3784        rng: &mut impl rand::Rng,
3785        edit_count: usize,
3786        cx: &mut Context<Self>,
3787    ) {
3788        use util::RandomCharIter;
3789
3790        let snapshot = self.read(cx);
3791        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3792        let mut last_end = None;
3793        for _ in 0..edit_count {
3794            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3795                break;
3796            }
3797
3798            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3799            let end =
3800                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3801            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3802            last_end = Some(end);
3803
3804            let mut range = start..end;
3805            if rng.random_bool(0.2) {
3806                mem::swap(&mut range.start, &mut range.end);
3807            }
3808
3809            let new_text_len = rng.random_range(0..10);
3810            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3811
3812            edits.push((range, new_text.into()));
3813        }
3814        log::info!("mutating multi-buffer with {:?}", edits);
3815        drop(snapshot);
3816
3817        self.edit(edits, None, cx);
3818    }
3819
3820    pub fn randomly_edit_excerpts(
3821        &mut self,
3822        rng: &mut impl rand::Rng,
3823        mutation_count: usize,
3824        cx: &mut Context<Self>,
3825    ) {
3826        use rand::prelude::*;
3827        use std::env;
3828        use util::RandomCharIter;
3829
3830        let max_excerpts = env::var("MAX_EXCERPTS")
3831            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3832            .unwrap_or(5);
3833
3834        let mut buffers = Vec::new();
3835        for _ in 0..mutation_count {
3836            if rng.random_bool(0.05) {
3837                log::info!("Clearing multi-buffer");
3838                self.clear(cx);
3839                continue;
3840            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3841                let ids = self.excerpt_ids();
3842                let mut excerpts = HashSet::default();
3843                for _ in 0..rng.random_range(0..ids.len()) {
3844                    excerpts.extend(ids.choose(rng).copied());
3845                }
3846
3847                let line_count = rng.random_range(0..5);
3848
3849                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3850
3851                self.expand_excerpts(
3852                    excerpts.iter().cloned(),
3853                    line_count,
3854                    ExpandExcerptDirection::UpAndDown,
3855                    cx,
3856                );
3857                continue;
3858            }
3859
3860            let excerpt_ids = self.excerpt_ids();
3861            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3862                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3863                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3864                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3865                    let buffer = buffers.last().unwrap().read(cx);
3866                    log::info!(
3867                        "Creating new buffer {} with text: {:?}",
3868                        buffer.remote_id(),
3869                        buffer.text()
3870                    );
3871                    buffers.last().unwrap().clone()
3872                } else {
3873                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3874                };
3875
3876                let buffer = buffer_handle.read(cx);
3877                let buffer_text = buffer.text();
3878                let ranges = (0..rng.random_range(0..5))
3879                    .map(|_| {
3880                        let end_ix =
3881                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3882                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3883                        ExcerptRange::new(start_ix..end_ix)
3884                    })
3885                    .collect::<Vec<_>>();
3886                log::info!(
3887                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3888                    buffer_handle.read(cx).remote_id(),
3889                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3890                    ranges
3891                        .iter()
3892                        .map(|r| &buffer_text[r.context.clone()])
3893                        .collect::<Vec<_>>()
3894                );
3895
3896                let excerpt_id =
3897                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3898                log::info!("Inserted with ids: {:?}", excerpt_id);
3899            } else {
3900                let remove_count = rng.random_range(1..=excerpt_ids.len());
3901                let mut excerpts_to_remove = excerpt_ids
3902                    .choose_multiple(rng, remove_count)
3903                    .cloned()
3904                    .collect::<Vec<_>>();
3905                let snapshot = self.snapshot.borrow();
3906                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3907                drop(snapshot);
3908                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3909                self.remove_excerpts(excerpts_to_remove, cx);
3910            }
3911        }
3912    }
3913
3914    pub fn randomly_mutate(
3915        &mut self,
3916        rng: &mut impl rand::Rng,
3917        mutation_count: usize,
3918        cx: &mut Context<Self>,
3919    ) {
3920        use rand::prelude::*;
3921
3922        if rng.random_bool(0.7) || self.singleton {
3923            let buffer = self
3924                .buffers
3925                .values()
3926                .choose(rng)
3927                .map(|state| state.buffer.clone());
3928
3929            if let Some(buffer) = buffer {
3930                buffer.update(cx, |buffer, cx| {
3931                    if rng.random() {
3932                        buffer.randomly_edit(rng, mutation_count, cx);
3933                    } else {
3934                        buffer.randomly_undo_redo(rng, cx);
3935                    }
3936                });
3937            } else {
3938                self.randomly_edit(rng, mutation_count, cx);
3939            }
3940        } else {
3941            self.randomly_edit_excerpts(rng, mutation_count, cx);
3942        }
3943
3944        self.check_invariants(cx);
3945    }
3946
3947    fn check_invariants(&self, cx: &App) {
3948        self.read(cx).check_invariants();
3949    }
3950}
3951
3952impl EventEmitter<Event> for MultiBuffer {}
3953
3954impl MultiBufferSnapshot {
3955    pub fn text(&self) -> String {
3956        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3957            .map(|chunk| chunk.text)
3958            .collect()
3959    }
3960
3961    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3962        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3963            .flat_map(|c| c.chars().rev())
3964    }
3965
3966    fn reversed_chunks_in_range(
3967        &self,
3968        range: Range<MultiBufferOffset>,
3969    ) -> ReversedMultiBufferChunks<'_> {
3970        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3971        cursor.seek(&range.end);
3972        let current_chunks = cursor.region().as_ref().map(|region| {
3973            let start_overshoot = range.start.saturating_sub(region.range.start);
3974            let end_overshoot = range.end - region.range.start;
3975            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3976            let start = region.buffer_range.start + start_overshoot;
3977            region.buffer.reversed_chunks_in_range(start..end)
3978        });
3979        ReversedMultiBufferChunks {
3980            cursor,
3981            current_chunks,
3982            start: range.start,
3983            offset: range.end,
3984        }
3985    }
3986
3987    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3988        let offset = position.to_offset(self);
3989        self.text_for_range(offset..self.len())
3990            .flat_map(|chunk| chunk.chars())
3991    }
3992
3993    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3994        self.chunks(range, false).map(|chunk| chunk.text)
3995    }
3996
3997    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3998        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3999            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
4000    }
4001
4002    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
4003    where
4004        T: ToOffset,
4005    {
4006        let position = position.to_offset(self);
4007        position == self.clip_offset(position, Bias::Left)
4008            && self
4009                .bytes_in_range(position..self.len())
4010                .flatten()
4011                .copied()
4012                .take(needle.len())
4013                .eq(needle.bytes())
4014    }
4015
4016    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4017        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4018    }
4019
4020    pub fn diff_hunks_in_range<T: ToPoint>(
4021        &self,
4022        range: Range<T>,
4023    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4024        let query_range = range.start.to_point(self)..range.end.to_point(self);
4025        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4026            let diff = self.diffs.get(&buffer.remote_id())?;
4027            let iter = if let Some(main_buffer) = &diff.main_buffer {
4028                let buffer_start = buffer.point_to_offset(buffer_range.start);
4029                let buffer_end = buffer.point_to_offset(buffer_range.end);
4030                itertools::Either::Left(
4031                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4032                        .map(move |hunk| (hunk, buffer, true)),
4033                )
4034            } else {
4035                let buffer_start = buffer.anchor_before(buffer_range.start);
4036                let buffer_end = buffer.anchor_after(buffer_range.end);
4037                itertools::Either::Right(
4038                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4039                        .map(move |hunk| (hunk, buffer, false)),
4040                )
4041            };
4042            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4043                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4044                    return None;
4045                }
4046                let range = if is_inverted {
4047                    hunk.diff_base_byte_range.to_point(&buffer)
4048                } else {
4049                    hunk.range.clone()
4050                };
4051                Some((range, (hunk, is_inverted)))
4052            }))
4053        })
4054        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4055            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4056            {
4057                return None;
4058            }
4059            let end_row = if range.end.column == 0 {
4060                range.end.row
4061            } else {
4062                range.end.row + 1
4063            };
4064
4065            let word_diffs =
4066                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4067                    .then(|| {
4068                        let mut word_diffs = Vec::new();
4069
4070                        if self.show_deleted_hunks || is_inverted {
4071                            let hunk_start_offset = if is_inverted {
4072                                Anchor::in_buffer(
4073                                    excerpt.id,
4074                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4075                                )
4076                                .to_offset(self)
4077                            } else {
4078                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4079                                    .to_offset(self)
4080                            };
4081
4082                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4083                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4084                            }));
4085                        }
4086
4087                        if !is_inverted {
4088                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4089                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4090                            }));
4091                        }
4092                        word_diffs
4093                    })
4094                    .unwrap_or_default();
4095
4096            let buffer_range = if is_inverted {
4097                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4098                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4099            } else {
4100                hunk.buffer_range.clone()
4101            };
4102            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4103                DiffHunkStatusKind::Deleted
4104            } else if hunk.diff_base_byte_range.is_empty() {
4105                DiffHunkStatusKind::Added
4106            } else {
4107                DiffHunkStatusKind::Modified
4108            };
4109            Some(MultiBufferDiffHunk {
4110                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4111                buffer_id: excerpt.buffer_id,
4112                excerpt_id: excerpt.id,
4113                buffer_range,
4114                word_diffs,
4115                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4116                    ..BufferOffset(hunk.diff_base_byte_range.end),
4117                status: DiffHunkStatus {
4118                    kind: status_kind,
4119                    secondary: hunk.secondary_status,
4120                },
4121            })
4122        })
4123    }
4124
4125    fn excerpts_for_range<T: ToOffset>(
4126        &self,
4127        range: Range<T>,
4128    ) -> impl Iterator<Item = &Excerpt> + '_ {
4129        let range = range.start.to_offset(self)..range.end.to_offset(self);
4130        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4131        cursor.seek(&range.start);
4132        std::iter::from_fn(move || {
4133            let region = cursor.region()?;
4134            if region.range.start > range.end
4135                || region.range.start == range.end && region.range.start > range.start
4136            {
4137                return None;
4138            }
4139            let excerpt = region.excerpt;
4140            cursor.next_excerpt_forwards();
4141            Some(excerpt)
4142        })
4143    }
4144
4145    pub fn excerpt_ids_for_range<T: ToOffset>(
4146        &self,
4147        range: Range<T>,
4148    ) -> impl Iterator<Item = ExcerptId> + '_ {
4149        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4150    }
4151
4152    pub fn buffer_ids_for_range<T: ToOffset>(
4153        &self,
4154        range: Range<T>,
4155    ) -> impl Iterator<Item = BufferId> + '_ {
4156        self.excerpts_for_range(range)
4157            .map(|excerpt| excerpt.buffer_id)
4158    }
4159
4160    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4161    ///
4162    /// The passed in anchors must be ordered.
4163    pub fn text_anchors_to_visible_anchors(
4164        &self,
4165        anchors: impl IntoIterator<Item = text::Anchor>,
4166    ) -> Vec<Option<Anchor>> {
4167        let anchors = anchors.into_iter();
4168        let mut result = Vec::with_capacity(anchors.size_hint().0);
4169        let mut anchors = anchors.peekable();
4170        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4171        'anchors: while let Some(anchor) = anchors.peek() {
4172            let Some(buffer_id) = anchor.buffer_id else {
4173                anchors.next();
4174                result.push(None);
4175                continue 'anchors;
4176            };
4177            let mut same_buffer_anchors =
4178                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4179
4180            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4181                let Some(mut next) = same_buffer_anchors.next() else {
4182                    continue 'anchors;
4183                };
4184                'excerpts: for locator in locators.iter() {
4185                    if cursor.seek_forward(&Some(locator), Bias::Left)
4186                        && let Some(excerpt) = cursor.item()
4187                    {
4188                        loop {
4189                            // anchor is before the first excerpt
4190                            if excerpt
4191                                .range
4192                                .context
4193                                .start
4194                                .cmp(&next, &excerpt.buffer)
4195                                .is_gt()
4196                            {
4197                                // so we skip it and try the next anchor
4198                                result.push(None);
4199                                match same_buffer_anchors.next() {
4200                                    Some(anchor) => next = anchor,
4201                                    None => continue 'anchors,
4202                                }
4203                            // anchor is within the excerpt
4204                            } else if excerpt
4205                                .range
4206                                .context
4207                                .end
4208                                .cmp(&next, &excerpt.buffer)
4209                                .is_ge()
4210                            {
4211                                // record it and all following anchors that are within
4212                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4213                                result.extend(
4214                                    same_buffer_anchors
4215                                        .peeking_take_while(|a| {
4216                                            excerpt
4217                                                .range
4218                                                .context
4219                                                .end
4220                                                .cmp(a, &excerpt.buffer)
4221                                                .is_ge()
4222                                        })
4223                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4224                                );
4225                                match same_buffer_anchors.next() {
4226                                    Some(anchor) => next = anchor,
4227                                    None => continue 'anchors,
4228                                }
4229                            // anchor is after the excerpt, try the next one
4230                            } else {
4231                                continue 'excerpts;
4232                            }
4233                        }
4234                    }
4235                }
4236                // account for `next`
4237                result.push(None);
4238            }
4239            result.extend(same_buffer_anchors.map(|_| None));
4240        }
4241
4242        result
4243    }
4244
4245    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4246        &self,
4247        ranges: impl Iterator<Item = Range<T>>,
4248    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4249        ranges.flat_map(|range| {
4250            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4251                .into_iter()
4252        })
4253    }
4254
4255    pub fn range_to_buffer_ranges<R, T>(
4256        &self,
4257        range: R,
4258    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4259    where
4260        R: RangeBounds<T>,
4261        T: ToOffset,
4262    {
4263        self.range_to_buffer_ranges_with_context(range)
4264            .into_iter()
4265            .map(|(buffer, range, id, _context)| (buffer, range, id))
4266            .collect()
4267    }
4268
4269    pub fn range_to_buffer_ranges_with_context<R, T>(
4270        &self,
4271        range: R,
4272    ) -> Vec<(
4273        &BufferSnapshot,
4274        Range<BufferOffset>,
4275        ExcerptId,
4276        Range<text::Anchor>,
4277    )>
4278    where
4279        R: RangeBounds<T>,
4280        T: ToOffset,
4281    {
4282        let start = match range.start_bound() {
4283            Bound::Included(start) => start.to_offset(self),
4284            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4285            Bound::Unbounded => MultiBufferOffset::ZERO,
4286        };
4287        let end_bound = match range.end_bound() {
4288            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4289            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4290            Bound::Unbounded => Bound::Unbounded,
4291        };
4292        let bounds = (Bound::Included(start), end_bound);
4293
4294        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4295        cursor.seek(&start);
4296
4297        let mut result: Vec<(
4298            &BufferSnapshot,
4299            Range<BufferOffset>,
4300            ExcerptId,
4301            Range<text::Anchor>,
4302        )> = Vec::new();
4303        while let Some(region) = cursor.region() {
4304            let dominated_by_end_bound = match end_bound {
4305                Bound::Included(end) => region.range.start > end,
4306                Bound::Excluded(end) => region.range.start >= end,
4307                Bound::Unbounded => false,
4308            };
4309            if dominated_by_end_bound {
4310                break;
4311            }
4312            if region.is_main_buffer {
4313                let start_overshoot = start.saturating_sub(region.range.start);
4314                let end_offset = match end_bound {
4315                    Bound::Included(end) | Bound::Excluded(end) => end,
4316                    Bound::Unbounded => region.range.end,
4317                };
4318                let end_overshoot = end_offset.saturating_sub(region.range.start);
4319                let start = region
4320                    .buffer_range
4321                    .end
4322                    .min(region.buffer_range.start + start_overshoot);
4323                let end = region
4324                    .buffer_range
4325                    .end
4326                    .min(region.buffer_range.start + end_overshoot);
4327                let context = region.excerpt.range.context.clone();
4328                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4329                    *excerpt_id == region.excerpt.id && prev_range.end == start
4330                }) {
4331                    prev.1.end = end;
4332                } else {
4333                    result.push((region.buffer, start..end, region.excerpt.id, context));
4334                }
4335            }
4336            cursor.next();
4337        }
4338
4339        if let Some(excerpt) = cursor.excerpt() {
4340            let dominated_by_prev_excerpt =
4341                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4342            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4343                let excerpt_position = self.len();
4344                if bounds.contains(&excerpt_position) {
4345                    let buffer_offset =
4346                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4347                    let context = excerpt.range.context.clone();
4348                    result.push((
4349                        &excerpt.buffer,
4350                        buffer_offset..buffer_offset,
4351                        excerpt.id,
4352                        context,
4353                    ));
4354                }
4355            }
4356        }
4357
4358        result
4359    }
4360
4361    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4362        &self,
4363        range: Range<T>,
4364    ) -> impl Iterator<
4365        Item = (
4366            &BufferSnapshot,
4367            Range<BufferOffset>,
4368            ExcerptId,
4369            Option<Anchor>,
4370        ),
4371    > + '_ {
4372        let start = range.start.to_offset(self);
4373        let end = range.end.to_offset(self);
4374
4375        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4376        cursor.seek(&start);
4377
4378        std::iter::from_fn(move || {
4379            let region = cursor.region()?;
4380            if region.range.start > end {
4381                return None;
4382            }
4383            let start_overshoot = start.saturating_sub(region.range.start);
4384            let end_overshoot = end.saturating_sub(region.range.start);
4385            let start = region
4386                .buffer_range
4387                .end
4388                .min(region.buffer_range.start + start_overshoot);
4389            let end = region
4390                .buffer_range
4391                .end
4392                .min(region.buffer_range.start + end_overshoot);
4393
4394            let region_excerpt_id = region.excerpt.id;
4395            let deleted_hunk_anchor = if region.is_main_buffer {
4396                None
4397            } else {
4398                Some(self.anchor_before(region.range.start))
4399            };
4400            let result = (
4401                region.buffer,
4402                start..end,
4403                region_excerpt_id,
4404                deleted_hunk_anchor,
4405            );
4406            cursor.next();
4407            Some(result)
4408        })
4409    }
4410
4411    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4412    /// coordinates.
4413    ///
4414    /// The given callback will be called for every excerpt intersecting the given range. It will
4415    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4416    /// The callback should return an iterator of metadata items from that buffer, each paired
4417    /// with a buffer range.
4418    ///
4419    /// The returned iterator yields each of these metadata items, paired with its range in
4420    /// multi-buffer coordinates.
4421    fn lift_buffer_metadata<'a, MBD, M, I>(
4422        &'a self,
4423        query_range: Range<MBD>,
4424        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4425    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4426    where
4427        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4428        MBD: MultiBufferDimension
4429            + Ord
4430            + Sub<Output = MBD::TextDimension>
4431            + ops::Add<MBD::TextDimension, Output = MBD>
4432            + ops::AddAssign<MBD::TextDimension>,
4433        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4434            + ops::Add<Output = MBD::TextDimension>
4435            + AddAssign<MBD::TextDimension>
4436            + Ord,
4437    {
4438        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4439        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4440
4441        // Find the excerpt and buffer offset where the given range ends.
4442        cursor.seek(&query_range.end);
4443        let mut range_end = None;
4444        while let Some(region) = cursor.region() {
4445            if region.is_main_buffer {
4446                let mut buffer_end = region.buffer_range.start;
4447                let overshoot = if query_range.end > region.range.start {
4448                    query_range.end - region.range.start
4449                } else {
4450                    <MBD::TextDimension>::default()
4451                };
4452                buffer_end = buffer_end + overshoot;
4453                range_end = Some((region.excerpt.id, buffer_end));
4454                break;
4455            }
4456            cursor.next();
4457        }
4458
4459        cursor.seek(&query_range.start);
4460
4461        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4462            && region.range.start > MBD::default()
4463        {
4464            cursor.prev()
4465        } else if let Some(region) = cursor.region()
4466            && region.is_main_buffer
4467            && region.diff_hunk_status.is_some()
4468        {
4469            cursor.prev();
4470            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4471                cursor.next();
4472            }
4473        }
4474
4475        iter::from_fn(move || {
4476            loop {
4477                let excerpt = cursor.excerpt()?;
4478
4479                // If we have already retrieved metadata for this excerpt, continue to use it.
4480                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4481                    .as_mut()
4482                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4483                {
4484                    Some(metadata)
4485                }
4486                // Otherwise, compute the intersection of the input range with the excerpt's range,
4487                // and retrieve the metadata for the resulting range.
4488                else {
4489                    let region = cursor.region()?;
4490                    let mut buffer_start;
4491                    if region.is_main_buffer {
4492                        buffer_start = region.buffer_range.start;
4493                        if query_range.start > region.range.start {
4494                            let overshoot = query_range.start - region.range.start;
4495                            buffer_start = buffer_start + overshoot;
4496                        }
4497                        buffer_start = buffer_start.min(region.buffer_range.end);
4498                    } else {
4499                        buffer_start = cursor.main_buffer_position()?;
4500                    };
4501                    let mut buffer_end = excerpt
4502                        .range
4503                        .context
4504                        .end
4505                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4506                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4507                        && excerpt.id == end_excerpt_id
4508                    {
4509                        buffer_end = buffer_end.min(end_buffer_offset);
4510                    }
4511
4512                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4513                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4514                    })
4515                };
4516
4517                // Visit each metadata item.
4518                if let Some((metadata_buffer_range, metadata)) =
4519                    metadata_iter.and_then(Iterator::next)
4520                {
4521                    // Find the multibuffer regions that contain the start and end of
4522                    // the metadata item's range.
4523                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4524                        while let Some(region) = cursor.region() {
4525                            if (region.is_main_buffer
4526                                && (region.buffer_range.end >= metadata_buffer_range.start
4527                                    || cursor.is_at_end_of_excerpt()))
4528                                || (!region.is_main_buffer
4529                                    && region.buffer_range.start == metadata_buffer_range.start)
4530                            {
4531                                break;
4532                            }
4533                            cursor.next();
4534                        }
4535                    }
4536                    let start_region = cursor.region()?.clone();
4537                    while let Some(region) = cursor.region() {
4538                        if region.is_main_buffer
4539                            && (region.buffer_range.end > metadata_buffer_range.end
4540                                || cursor.is_at_end_of_excerpt())
4541                        {
4542                            break;
4543                        }
4544                        cursor.next();
4545                    }
4546                    let end_region = cursor.region();
4547
4548                    // Convert the metadata item's range into multibuffer coordinates.
4549                    let mut start_position = start_region.range.start;
4550                    let region_buffer_start = start_region.buffer_range.start;
4551                    if start_region.is_main_buffer
4552                        && metadata_buffer_range.start > region_buffer_start
4553                    {
4554                        start_position =
4555                            start_position + (metadata_buffer_range.start - region_buffer_start);
4556                        start_position = start_position.min(start_region.range.end);
4557                    }
4558
4559                    let mut end_position = self.max_position();
4560                    if let Some(end_region) = &end_region {
4561                        end_position = end_region.range.start;
4562                        debug_assert!(end_region.is_main_buffer);
4563                        let region_buffer_start = end_region.buffer_range.start;
4564                        if metadata_buffer_range.end > region_buffer_start {
4565                            end_position =
4566                                end_position + (metadata_buffer_range.end - region_buffer_start);
4567                        }
4568                        end_position = end_position.min(end_region.range.end);
4569                    }
4570
4571                    if start_position <= query_range.end && end_position >= query_range.start {
4572                        return Some((start_position..end_position, metadata, excerpt));
4573                    }
4574                }
4575                // When there are no more metadata items for this excerpt, move to the next excerpt.
4576                else {
4577                    current_excerpt_metadata.take();
4578                    if let Some((end_excerpt_id, _)) = range_end
4579                        && excerpt.id == end_excerpt_id
4580                    {
4581                        return None;
4582                    }
4583                    cursor.next_excerpt_forwards();
4584                }
4585            }
4586        })
4587    }
4588
4589    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4590        let offset = position.to_offset(self);
4591
4592        let mut cursor = self
4593            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4594            );
4595        cursor.seek(&DimensionPair {
4596            key: offset,
4597            value: None,
4598        });
4599        cursor.seek_to_start_of_current_excerpt();
4600        let excerpt = cursor.excerpt()?;
4601
4602        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4603        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4604        let current_position = self
4605            .anchor_before(offset)
4606            .text_anchor
4607            .to_offset(&excerpt.buffer);
4608
4609        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4610            if let Some(main_buffer) = &diff.main_buffer {
4611                for hunk in diff
4612                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4613                {
4614                    if hunk.diff_base_byte_range.end >= current_position {
4615                        continue;
4616                    }
4617                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4618                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4619                    return Some(MultiBufferRow(start.row));
4620                }
4621            } else {
4622                let excerpt_end = excerpt
4623                    .buffer
4624                    .anchor_before(excerpt_end.min(current_position));
4625                for hunk in diff.hunks_intersecting_range_rev(
4626                    excerpt.range.context.start..excerpt_end,
4627                    &excerpt.buffer,
4628                ) {
4629                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4630                    if hunk_end >= current_position {
4631                        continue;
4632                    }
4633                    let start =
4634                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4635                    return Some(MultiBufferRow(start.row));
4636                }
4637            }
4638        }
4639
4640        loop {
4641            cursor.prev_excerpt();
4642            let excerpt = cursor.excerpt()?;
4643
4644            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4645                continue;
4646            };
4647            if let Some(main_buffer) = &diff.main_buffer {
4648                let Some(hunk) = diff
4649                    .hunks_intersecting_base_text_range_rev(
4650                        excerpt.range.context.to_offset(&excerpt.buffer),
4651                        main_buffer,
4652                    )
4653                    .next()
4654                else {
4655                    continue;
4656                };
4657                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4658                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4659                return Some(MultiBufferRow(start.row));
4660            } else {
4661                let Some(hunk) = diff
4662                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4663                    .next()
4664                else {
4665                    continue;
4666                };
4667                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4668                return Some(MultiBufferRow(start.row));
4669            }
4670        }
4671    }
4672
4673    pub fn has_diff_hunks(&self) -> bool {
4674        self.diffs.values().any(|diff| !diff.is_empty())
4675    }
4676
4677    pub fn is_inside_word<T: ToOffset>(
4678        &self,
4679        position: T,
4680        scope_context: Option<CharScopeContext>,
4681    ) -> bool {
4682        let position = position.to_offset(self);
4683        let classifier = self
4684            .char_classifier_at(position)
4685            .scope_context(scope_context);
4686        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4687        let prev_char_kind = self
4688            .reversed_chars_at(position)
4689            .next()
4690            .map(|c| classifier.kind(c));
4691        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4692    }
4693
4694    pub fn surrounding_word<T: ToOffset>(
4695        &self,
4696        start: T,
4697        scope_context: Option<CharScopeContext>,
4698    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4699        let mut start = start.to_offset(self);
4700        let mut end = start;
4701        let mut next_chars = self.chars_at(start).peekable();
4702        let mut prev_chars = self.reversed_chars_at(start).peekable();
4703
4704        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4705
4706        let word_kind = cmp::max(
4707            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4708            next_chars.peek().copied().map(|c| classifier.kind(c)),
4709        );
4710
4711        for ch in prev_chars {
4712            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4713                start -= ch.len_utf8();
4714            } else {
4715                break;
4716            }
4717        }
4718
4719        for ch in next_chars {
4720            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4721                end += ch.len_utf8();
4722            } else {
4723                break;
4724            }
4725        }
4726
4727        (start..end, word_kind)
4728    }
4729
4730    pub fn char_kind_before<T: ToOffset>(
4731        &self,
4732        start: T,
4733        scope_context: Option<CharScopeContext>,
4734    ) -> Option<CharKind> {
4735        let start = start.to_offset(self);
4736        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4737        self.reversed_chars_at(start)
4738            .next()
4739            .map(|ch| classifier.kind(ch))
4740    }
4741
4742    pub fn is_singleton(&self) -> bool {
4743        self.singleton
4744    }
4745
4746    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4747        if self.singleton {
4748            self.excerpts
4749                .iter()
4750                .next()
4751                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4752        } else {
4753            None
4754        }
4755    }
4756
4757    pub fn len(&self) -> MultiBufferOffset {
4758        self.diff_transforms.summary().output.len
4759    }
4760
4761    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4762        MBD::from_summary(&self.text_summary())
4763    }
4764
4765    pub fn is_empty(&self) -> bool {
4766        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4767    }
4768
4769    pub fn widest_line_number(&self) -> u32 {
4770        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4771        self.excerpts.summary().widest_line_number + 1
4772    }
4773
4774    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4775        let range = range.start.to_offset(self)..range.end.to_offset(self);
4776        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4777        excerpts.seek(&range.start);
4778
4779        let mut chunk;
4780        let mut has_trailing_newline;
4781        let excerpt_bytes;
4782        if let Some(region) = excerpts.region() {
4783            let mut bytes = region.buffer.bytes_in_range(
4784                region.buffer_range.start + (range.start - region.range.start)
4785                    ..(region.buffer_range.start + (range.end - region.range.start))
4786                        .min(region.buffer_range.end),
4787            );
4788            chunk = bytes.next().unwrap_or(&[][..]);
4789            excerpt_bytes = Some(bytes);
4790            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4791            if chunk.is_empty() && has_trailing_newline {
4792                chunk = b"\n";
4793                has_trailing_newline = false;
4794            }
4795        } else {
4796            chunk = &[][..];
4797            excerpt_bytes = None;
4798            has_trailing_newline = false;
4799        };
4800
4801        MultiBufferBytes {
4802            range,
4803            cursor: excerpts,
4804            excerpt_bytes,
4805            has_trailing_newline,
4806            chunk,
4807        }
4808    }
4809
4810    pub fn reversed_bytes_in_range<T: ToOffset>(
4811        &self,
4812        range: Range<T>,
4813    ) -> ReversedMultiBufferBytes<'_> {
4814        let range = range.start.to_offset(self)..range.end.to_offset(self);
4815        let mut chunks = self.reversed_chunks_in_range(range.clone());
4816        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4817        ReversedMultiBufferBytes {
4818            range,
4819            chunks,
4820            chunk,
4821        }
4822    }
4823
4824    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4825        let mut cursor = self.cursor::<Point, Point>();
4826        cursor.seek(&Point::new(start_row.0, 0));
4827        let mut result = MultiBufferRows {
4828            point: Point::new(0, 0),
4829            is_empty: self.excerpts.is_empty(),
4830            is_singleton: self.is_singleton(),
4831            cursor,
4832        };
4833        result.seek(start_row);
4834        result
4835    }
4836
4837    pub fn chunks<T: ToOffset>(
4838        &self,
4839        range: Range<T>,
4840        language_aware: bool,
4841    ) -> MultiBufferChunks<'_> {
4842        let mut chunks = MultiBufferChunks {
4843            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4844                ..ExcerptDimension(MultiBufferOffset::ZERO),
4845            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4846            excerpts: self.excerpts.cursor(()),
4847            diff_transforms: self.diff_transforms.cursor(()),
4848            diffs: &self.diffs,
4849            diff_base_chunks: None,
4850            excerpt_chunks: None,
4851            buffer_chunk: None,
4852            language_aware,
4853        };
4854        let range = range.start.to_offset(self)..range.end.to_offset(self);
4855        chunks.seek(range);
4856        chunks
4857    }
4858
4859    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4860        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4861    }
4862
4863    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4864        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4865    }
4866
4867    pub fn clip_offset_utf16(
4868        &self,
4869        offset: MultiBufferOffsetUtf16,
4870        bias: Bias,
4871    ) -> MultiBufferOffsetUtf16 {
4872        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4873    }
4874
4875    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4876        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4877            buffer.clip_point_utf16(Unclipped(point), bias)
4878        })
4879    }
4880
4881    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4882        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4883    }
4884
4885    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4886        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4887    }
4888
4889    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4890        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4891    }
4892
4893    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4894        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4895    }
4896
4897    #[instrument(skip_all)]
4898    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4899        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4900    }
4901
4902    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4903        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4904    }
4905
4906    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4907        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4908    }
4909
4910    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4911        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4912    }
4913
4914    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4915        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4916    }
4917
4918    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4919        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4920    }
4921
4922    fn clip_dimension<MBD, BD>(
4923        &self,
4924        position: MBD,
4925        bias: Bias,
4926        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4927    ) -> MBD
4928    where
4929        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4930        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4931    {
4932        let mut cursor = self.cursor::<MBD, BD>();
4933        cursor.seek(&position);
4934        if let Some(region) = cursor.region() {
4935            if position >= region.range.end {
4936                return region.range.end;
4937            }
4938            let overshoot = position - region.range.start;
4939            let mut buffer_position = region.buffer_range.start;
4940            buffer_position += overshoot;
4941            let clipped_buffer_position =
4942                clip_buffer_position(region.buffer, buffer_position, bias);
4943            let mut position = region.range.start;
4944            position += clipped_buffer_position - region.buffer_range.start;
4945            position
4946        } else {
4947            self.max_position()
4948        }
4949    }
4950
4951    #[instrument(skip_all)]
4952    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4953        &self,
4954        key: MBR1,
4955        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4956    ) -> MBR2
4957    where
4958        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4959        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4960        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4961        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4962    {
4963        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4964        cursor.seek(&DimensionPair { key, value: None });
4965        if let Some(region) = cursor.region() {
4966            if key >= region.range.end.key {
4967                return region.range.end.value.unwrap();
4968            }
4969            let start_key = region.range.start.key;
4970            let start_value = region.range.start.value.unwrap();
4971            let buffer_start_key = region.buffer_range.start.key;
4972            let buffer_start_value = region.buffer_range.start.value.unwrap();
4973            let mut buffer_key = buffer_start_key;
4974            buffer_key += key - start_key;
4975            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4976            let mut result = start_value;
4977            result += buffer_value - buffer_start_value;
4978            result
4979        } else {
4980            self.max_position()
4981        }
4982    }
4983
4984    pub fn point_to_buffer_offset<T: ToOffset>(
4985        &self,
4986        point: T,
4987    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4988        let offset = point.to_offset(self);
4989        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4990        cursor.seek(&offset);
4991        let region = cursor.region()?;
4992        let overshoot = offset - region.range.start;
4993        let buffer_offset = region.buffer_range.start + overshoot;
4994        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4995            && region.has_trailing_newline
4996            && !region.is_main_buffer
4997        {
4998            let main_buffer_position = cursor.main_buffer_position()?;
4999            let buffer_snapshot = &cursor.excerpt()?.buffer;
5000            return Some((buffer_snapshot, main_buffer_position));
5001        } else if buffer_offset > BufferOffset(region.buffer.len()) {
5002            return None;
5003        }
5004        Some((region.buffer, buffer_offset))
5005    }
5006
5007    pub fn point_to_buffer_point(
5008        &self,
5009        point: Point,
5010    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5011        let mut cursor = self.cursor::<Point, Point>();
5012        cursor.seek(&point);
5013        let region = cursor.region()?;
5014        let overshoot = point - region.range.start;
5015        let buffer_point = region.buffer_range.start + overshoot;
5016        let excerpt = cursor.excerpt()?;
5017        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5018            && region.has_trailing_newline
5019            && !region.is_main_buffer
5020        {
5021            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5022        } else if buffer_point > region.buffer.max_point() {
5023            return None;
5024        }
5025        Some((region.buffer, buffer_point, excerpt.id))
5026    }
5027
5028    pub fn suggested_indents(
5029        &self,
5030        rows: impl IntoIterator<Item = u32>,
5031        cx: &App,
5032    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5033        let mut result = BTreeMap::new();
5034        self.suggested_indents_callback(
5035            rows,
5036            &mut |row, indent| {
5037                result.insert(row, indent);
5038                ControlFlow::Continue(())
5039            },
5040            cx,
5041        );
5042        result
5043    }
5044
5045    // move this to be a generator once those are a thing
5046    pub fn suggested_indents_callback(
5047        &self,
5048        rows: impl IntoIterator<Item = u32>,
5049        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5050        cx: &App,
5051    ) {
5052        let mut rows_for_excerpt = Vec::new();
5053        let mut cursor = self.cursor::<Point, Point>();
5054        let mut rows = rows.into_iter().peekable();
5055        let mut prev_row = u32::MAX;
5056        let mut prev_language_indent_size = IndentSize::default();
5057
5058        while let Some(row) = rows.next() {
5059            cursor.seek(&Point::new(row, 0));
5060            let Some(region) = cursor.region() else {
5061                continue;
5062            };
5063
5064            // Retrieve the language and indent size once for each disjoint region being indented.
5065            let single_indent_size = if row.saturating_sub(1) == prev_row {
5066                prev_language_indent_size
5067            } else {
5068                region
5069                    .buffer
5070                    .language_indent_size_at(Point::new(row, 0), cx)
5071            };
5072            prev_language_indent_size = single_indent_size;
5073            prev_row = row;
5074
5075            let start_buffer_row = region.buffer_range.start.row;
5076            let start_multibuffer_row = region.range.start.row;
5077            let end_multibuffer_row = region.range.end.row;
5078
5079            rows_for_excerpt.push(row);
5080            while let Some(next_row) = rows.peek().copied() {
5081                if end_multibuffer_row > next_row {
5082                    rows_for_excerpt.push(next_row);
5083                    rows.next();
5084                } else {
5085                    break;
5086                }
5087            }
5088
5089            let buffer_rows = rows_for_excerpt
5090                .drain(..)
5091                .map(|row| start_buffer_row + row - start_multibuffer_row);
5092            let buffer_indents = region
5093                .buffer
5094                .suggested_indents(buffer_rows, single_indent_size);
5095            for (row, indent) in buffer_indents {
5096                if cb(
5097                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5098                    indent,
5099                )
5100                .is_break()
5101                {
5102                    return;
5103                }
5104            }
5105        }
5106    }
5107
5108    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5109        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5110            let mut size = buffer.indent_size_for_line(range.start.row);
5111            size.len = size
5112                .len
5113                .min(range.end.column)
5114                .saturating_sub(range.start.column);
5115            size
5116        } else {
5117            IndentSize::spaces(0)
5118        }
5119    }
5120
5121    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5122        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5123            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5124        } else {
5125            LineIndent::spaces(0)
5126        }
5127    }
5128
5129    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5130        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5131
5132        if self.language_settings(cx).extend_comment_on_newline
5133            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5134        {
5135            let delimiters = language_scope.line_comment_prefixes();
5136            for delimiter in delimiters {
5137                if *self
5138                    .chars_at(Point::new(row.0, indent.len() as u32))
5139                    .take(delimiter.chars().count())
5140                    .collect::<String>()
5141                    .as_str()
5142                    == **delimiter
5143                {
5144                    indent.push_str(delimiter);
5145                    break;
5146                }
5147            }
5148        }
5149
5150        indent
5151    }
5152
5153    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5154    where
5155        T: ToOffset,
5156    {
5157        for char in self.reversed_chars_at(position) {
5158            if !char.is_whitespace() {
5159                return false;
5160            }
5161            if char == '\n' {
5162                return true;
5163            }
5164        }
5165        true
5166    }
5167
5168    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5169        while row.0 > 0 {
5170            row.0 -= 1;
5171            if !self.is_line_blank(row) {
5172                return Some(row);
5173            }
5174        }
5175        None
5176    }
5177
5178    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5179        if let Some((_, range)) = self.buffer_line_for_row(row) {
5180            range.end.column - range.start.column
5181        } else {
5182            0
5183        }
5184    }
5185
5186    pub fn buffer_line_for_row(
5187        &self,
5188        row: MultiBufferRow,
5189    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5190        let mut cursor = self.cursor::<Point, Point>();
5191        let point = Point::new(row.0, 0);
5192        cursor.seek(&point);
5193        let region = cursor.region()?;
5194        let overshoot = point.min(region.range.end) - region.range.start;
5195        let buffer_point = region.buffer_range.start + overshoot;
5196        if buffer_point.row > region.buffer_range.end.row {
5197            return None;
5198        }
5199        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5200        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5201            .min(region.buffer_range.end);
5202        Some((region.buffer, line_start..line_end))
5203    }
5204
5205    pub fn max_point(&self) -> Point {
5206        self.text_summary().lines
5207    }
5208
5209    pub fn max_row(&self) -> MultiBufferRow {
5210        MultiBufferRow(self.text_summary().lines.row)
5211    }
5212
5213    pub fn text_summary(&self) -> MBTextSummary {
5214        self.diff_transforms.summary().output
5215    }
5216
5217    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5218    where
5219        MBD: MultiBufferDimension + AddAssign,
5220        O: ToOffset,
5221    {
5222        let range = range.start.to_offset(self)..range.end.to_offset(self);
5223        let mut cursor = self
5224            .diff_transforms
5225            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5226        cursor.seek(&range.start, Bias::Right);
5227
5228        let Some(first_transform) = cursor.item() else {
5229            return MBD::from_summary(&MBTextSummary::default());
5230        };
5231
5232        let diff_transform_start = cursor.start().0;
5233        let diff_transform_end = cursor.end().0;
5234        let diff_start = range.start;
5235        let start_overshoot = diff_start - diff_transform_start;
5236        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5237
5238        let mut result = match first_transform {
5239            DiffTransform::BufferContent { .. } => {
5240                let excerpt_start = cursor.start().1 + start_overshoot;
5241                let excerpt_end = cursor.start().1 + end_overshoot;
5242                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5243            }
5244            DiffTransform::DeletedHunk {
5245                buffer_id,
5246                base_text_byte_range,
5247                has_trailing_newline,
5248                ..
5249            } => {
5250                let buffer_start = base_text_byte_range.start + start_overshoot;
5251                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5252                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5253                    panic!("{:?} is in non-existent deleted hunk", range.start)
5254                };
5255
5256                let include_trailing_newline =
5257                    *has_trailing_newline && range.end >= diff_transform_end;
5258                if include_trailing_newline {
5259                    buffer_end -= 1;
5260                }
5261
5262                let mut summary = base_text
5263                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5264
5265                if include_trailing_newline {
5266                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5267                        &TextSummary::newline(),
5268                    ))
5269                }
5270
5271                let mut result = MBD::default();
5272                result.add_text_dim(&summary);
5273                result
5274            }
5275        };
5276        if range.end < diff_transform_end {
5277            return result;
5278        }
5279
5280        cursor.next();
5281        result.add_mb_text_summary(
5282            &cursor
5283                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5284                .0,
5285        );
5286
5287        let Some(last_transform) = cursor.item() else {
5288            return result;
5289        };
5290
5291        let overshoot = range.end - cursor.start().0;
5292        let suffix = match last_transform {
5293            DiffTransform::BufferContent { .. } => {
5294                let end = cursor.start().1 + overshoot;
5295                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5296            }
5297            DiffTransform::DeletedHunk {
5298                base_text_byte_range,
5299                buffer_id,
5300                has_trailing_newline,
5301                ..
5302            } => {
5303                let buffer_end = base_text_byte_range.start + overshoot;
5304                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5305                    panic!("{:?} is in non-existent deleted hunk", range.end)
5306                };
5307
5308                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5309                    base_text_byte_range.start..buffer_end,
5310                );
5311                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5312                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5313                        &TextSummary::from("\n"),
5314                    ))
5315                }
5316
5317                let mut result = MBD::default();
5318                result.add_text_dim(&suffix);
5319                result
5320            }
5321        };
5322
5323        result += suffix;
5324        result
5325    }
5326
5327    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5328    where
5329        MBD: MultiBufferDimension + AddAssign,
5330    {
5331        let mut summary = MBD::default();
5332        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5333        cursor.seek(&range.start, Bias::Right);
5334        if let Some(excerpt) = cursor.item() {
5335            let mut end_before_newline = cursor.end();
5336            if excerpt.has_trailing_newline {
5337                end_before_newline -= 1;
5338            }
5339
5340            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5341            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5342            let end_in_excerpt =
5343                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5344            summary.add_text_dim(
5345                &excerpt
5346                    .buffer
5347                    .text_summary_for_range::<MBD::TextDimension, _>(
5348                        start_in_excerpt..end_in_excerpt,
5349                    ),
5350            );
5351
5352            if range.end > end_before_newline {
5353                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5354            }
5355
5356            cursor.next();
5357        }
5358
5359        if range.end > *cursor.start() {
5360            summary += cursor
5361                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5362                .0;
5363            if let Some(excerpt) = cursor.item() {
5364                range.end = cmp::max(*cursor.start(), range.end);
5365
5366                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5367                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5368                summary.add_text_dim(
5369                    &excerpt
5370                        .buffer
5371                        .text_summary_for_range::<MBD::TextDimension, _>(
5372                            excerpt_start..end_in_excerpt,
5373                        ),
5374                );
5375            }
5376        }
5377
5378        summary
5379    }
5380
5381    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5382    where
5383        MBD: MultiBufferDimension
5384            + Ord
5385            + Sub<Output = MBD::TextDimension>
5386            + Sub<MBD::TextDimension, Output = MBD>
5387            + AddAssign<MBD::TextDimension>
5388            + Add<MBD::TextDimension, Output = MBD>,
5389        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5390    {
5391        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5392        let locator = self.excerpt_locator_for_id(excerpt_id);
5393        let (start, _, mut item) = self
5394            .excerpts
5395            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5396        let mut start = MBD::from_summary(&start.text);
5397        if item.is_none() && excerpt_id == ExcerptId::max() {
5398            item = self.excerpts.last();
5399            if let Some(last_summary) = self.excerpts.last_summary() {
5400                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5401            }
5402        }
5403
5404        let excerpt_start_position = ExcerptDimension(start);
5405        if self.diff_transforms.is_empty() {
5406            if let Some(excerpt) = item {
5407                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5408                    return excerpt_start_position.0;
5409                }
5410                let excerpt_buffer_start = excerpt
5411                    .range
5412                    .context
5413                    .start
5414                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5415                let excerpt_buffer_end = excerpt
5416                    .range
5417                    .context
5418                    .end
5419                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5420                let buffer_summary = anchor
5421                    .text_anchor
5422                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5423                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5424                let mut position = excerpt_start_position;
5425                if summary > excerpt_buffer_start {
5426                    position += summary - excerpt_buffer_start;
5427                }
5428
5429                position.0
5430            } else {
5431                excerpt_start_position.0
5432            }
5433        } else {
5434            let mut diff_transforms_cursor = self
5435                .diff_transforms
5436                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5437            diff_transforms_cursor.next();
5438
5439            if let Some(excerpt) = item {
5440                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5441                    return self.resolve_summary_for_min_or_max_anchor(
5442                        &Anchor::min(),
5443                        excerpt_start_position,
5444                        &mut diff_transforms_cursor,
5445                    );
5446                }
5447                let excerpt_buffer_start = excerpt
5448                    .range
5449                    .context
5450                    .start
5451                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5452                let excerpt_buffer_end = excerpt
5453                    .range
5454                    .context
5455                    .end
5456                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5457                let buffer_summary = anchor
5458                    .text_anchor
5459                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5460                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5461                let mut position = excerpt_start_position;
5462                if summary > excerpt_buffer_start {
5463                    position += summary - excerpt_buffer_start;
5464                }
5465
5466                if diff_transforms_cursor.start().0 < position {
5467                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5468                }
5469                self.resolve_summary_for_anchor(
5470                    &anchor,
5471                    position,
5472                    &mut diff_transforms_cursor,
5473                    &excerpt.buffer,
5474                )
5475            } else {
5476                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5477                self.resolve_summary_for_min_or_max_anchor(
5478                    &Anchor::max(),
5479                    excerpt_start_position,
5480                    &mut diff_transforms_cursor,
5481                )
5482            }
5483        }
5484    }
5485
5486    /// Maps an anchor's excerpt-space position to its output-space position by
5487    /// walking the diff transforms. The cursor is shared across consecutive
5488    /// calls, so it may already be partway through the transform list.
5489    fn resolve_summary_for_anchor<MBD>(
5490        &self,
5491        anchor: &Anchor,
5492        excerpt_position: ExcerptDimension<MBD>,
5493        diff_transforms: &mut Cursor<
5494            DiffTransform,
5495            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5496        >,
5497        excerpt_buffer: &text::BufferSnapshot,
5498    ) -> MBD
5499    where
5500        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5501    {
5502        loop {
5503            let transform_end_position = diff_transforms.end().0;
5504            let item = diff_transforms.item();
5505            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5506
5507            // A right-biased anchor at a transform boundary belongs to the
5508            // *next* transform, so advance past the current one.
5509            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5510                diff_transforms.next();
5511                continue;
5512            }
5513
5514            let mut position = diff_transforms.start().1;
5515            match item {
5516                Some(DiffTransform::DeletedHunk {
5517                    buffer_id,
5518                    base_text_byte_range,
5519                    hunk_info,
5520                    ..
5521                }) => {
5522                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5523                        && let Some(base_text) =
5524                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5525                        && diff_base_anchor.is_valid(&base_text)
5526                    {
5527                        // The anchor carries a diff-base position — resolve it
5528                        // to a location inside the deleted hunk.
5529                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5530                        if base_text_offset >= base_text_byte_range.start
5531                            && base_text_offset <= base_text_byte_range.end
5532                        {
5533                            let position_in_hunk = base_text
5534                                .text_summary_for_range::<MBD::TextDimension, _>(
5535                                    base_text_byte_range.start..base_text_offset,
5536                                );
5537                            position.0.add_text_dim(&position_in_hunk);
5538                        } else if at_transform_end {
5539                            // diff_base offset falls outside this hunk's range;
5540                            // advance to see if the next transform is a better fit.
5541                            diff_transforms.next();
5542                            continue;
5543                        }
5544                    } else if at_transform_end
5545                        && anchor
5546                            .text_anchor
5547                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5548                            .is_gt()
5549                    {
5550                        // The anchor has no (valid) diff-base position, so it
5551                        // belongs in the buffer content, not in the deleted
5552                        // hunk. However, after an edit deletes the text between
5553                        // the hunk boundary and this anchor, both resolve to
5554                        // the same excerpt_position—landing us here on the
5555                        // DeletedHunk left behind by the shared cursor. Use the
5556                        // CRDT ordering to detect that the anchor is strictly
5557                        // *past* the hunk boundary and skip to the following
5558                        // BufferContent.
5559                        diff_transforms.next();
5560                        continue;
5561                    }
5562                }
5563                _ => {
5564                    // On a BufferContent (or no transform). If the anchor
5565                    // carries a diff_base_anchor it needs a DeletedHunk, so
5566                    // advance to find one.
5567                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5568                        diff_transforms.next();
5569                        continue;
5570                    }
5571                    let overshoot = excerpt_position - diff_transforms.start().0;
5572                    position += overshoot;
5573                }
5574            }
5575
5576            return position.0;
5577        }
5578    }
5579
5580    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5581    fn resolve_summary_for_min_or_max_anchor<MBD>(
5582        &self,
5583        anchor: &Anchor,
5584        excerpt_position: ExcerptDimension<MBD>,
5585        diff_transforms: &mut Cursor<
5586            DiffTransform,
5587            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5588        >,
5589    ) -> MBD
5590    where
5591        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5592    {
5593        loop {
5594            let transform_end_position = diff_transforms.end().0;
5595            let item = diff_transforms.item();
5596            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5597
5598            // A right-biased anchor at a transform boundary belongs to the
5599            // *next* transform, so advance past the current one.
5600            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5601                diff_transforms.next();
5602                continue;
5603            }
5604
5605            let mut position = diff_transforms.start().1;
5606            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5607                let overshoot = excerpt_position - diff_transforms.start().0;
5608                position += overshoot;
5609            }
5610
5611            return position.0;
5612        }
5613    }
5614
5615    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5616        let mut cursor = self
5617            .excerpts
5618            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5619        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5620
5621        cursor.seek(&Some(locator), Bias::Left);
5622        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5623            cursor.prev();
5624        }
5625
5626        let mut position = cursor.start().1;
5627        if let Some(excerpt) = cursor.item()
5628            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5629        {
5630            let excerpt_buffer_start = excerpt
5631                .buffer
5632                .offset_for_anchor(&excerpt.range.context.start);
5633            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5634            let buffer_position = cmp::min(
5635                excerpt_buffer_end,
5636                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5637            );
5638            if buffer_position > excerpt_buffer_start {
5639                position += buffer_position - excerpt_buffer_start;
5640            }
5641        }
5642        position
5643    }
5644
5645    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5646        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5647            excerpt_id = *replacement;
5648        }
5649        excerpt_id
5650    }
5651
5652    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5653    where
5654        MBD: MultiBufferDimension
5655            + Ord
5656            + Sub<Output = MBD::TextDimension>
5657            + AddAssign<MBD::TextDimension>,
5658        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5659        I: 'a + IntoIterator<Item = &'a Anchor>,
5660    {
5661        let mut anchors = anchors.into_iter().peekable();
5662        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5663        let mut diff_transforms_cursor = self
5664            .diff_transforms
5665            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5666        diff_transforms_cursor.next();
5667
5668        let mut summaries = Vec::new();
5669        while let Some(anchor) = anchors.peek() {
5670            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5671
5672            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5673                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5674            });
5675
5676            let locator = self.excerpt_locator_for_id(excerpt_id);
5677            cursor.seek_forward(locator, Bias::Left);
5678            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5679                cursor.prev();
5680            }
5681
5682            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5683            if let Some(excerpt) = cursor.item() {
5684                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5685                    let position = self.resolve_summary_for_min_or_max_anchor(
5686                        &Anchor::min(),
5687                        excerpt_start_position,
5688                        &mut diff_transforms_cursor,
5689                    );
5690                    summaries.extend(excerpt_anchors.map(|_| position));
5691                    continue;
5692                }
5693                let excerpt_buffer_start = excerpt
5694                    .range
5695                    .context
5696                    .start
5697                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5698                let excerpt_buffer_end = excerpt
5699                    .range
5700                    .context
5701                    .end
5702                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5703                for (buffer_summary, anchor) in excerpt
5704                    .buffer
5705                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5706                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5707                    )
5708                {
5709                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5710                    let mut position = excerpt_start_position;
5711                    if summary > excerpt_buffer_start {
5712                        position += summary - excerpt_buffer_start;
5713                    }
5714
5715                    if diff_transforms_cursor.start().0 < position {
5716                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5717                    }
5718
5719                    summaries.push(self.resolve_summary_for_anchor(
5720                        anchor,
5721                        position,
5722                        &mut diff_transforms_cursor,
5723                        &excerpt.buffer,
5724                    ));
5725                }
5726            } else {
5727                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5728                let position = self.resolve_summary_for_min_or_max_anchor(
5729                    &Anchor::max(),
5730                    excerpt_start_position,
5731                    &mut diff_transforms_cursor,
5732                );
5733                summaries.extend(excerpt_anchors.map(|_| position));
5734            }
5735        }
5736
5737        summaries
5738    }
5739
5740    pub fn dimensions_from_points<'a, MBD>(
5741        &'a self,
5742        points: impl 'a + IntoIterator<Item = Point>,
5743    ) -> impl 'a + Iterator<Item = MBD>
5744    where
5745        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5746    {
5747        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5748        cursor.seek(&DimensionPair {
5749            key: Point::default(),
5750            value: None,
5751        });
5752        let mut points = points.into_iter();
5753        iter::from_fn(move || {
5754            let point = points.next()?;
5755
5756            cursor.seek_forward(&DimensionPair {
5757                key: point,
5758                value: None,
5759            });
5760
5761            if let Some(region) = cursor.region() {
5762                let overshoot = point - region.range.start.key;
5763                let buffer_point = region.buffer_range.start + overshoot;
5764                let mut position = region.range.start.value.unwrap();
5765                position.add_text_dim(
5766                    &region
5767                        .buffer
5768                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5769                );
5770                if point == region.range.end.key && region.has_trailing_newline {
5771                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5772                }
5773                Some(position)
5774            } else {
5775                Some(MBD::from_summary(&self.text_summary()))
5776            }
5777        })
5778    }
5779
5780    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5781    where
5782        I: 'a + IntoIterator<Item = &'a Anchor>,
5783    {
5784        let mut anchors = anchors.into_iter().enumerate().peekable();
5785        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5786        cursor.next();
5787
5788        let mut result = Vec::new();
5789
5790        while let Some((_, anchor)) = anchors.peek() {
5791            let old_excerpt_id = anchor.excerpt_id;
5792
5793            // Find the location where this anchor's excerpt should be.
5794            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5795            cursor.seek_forward(&Some(old_locator), Bias::Left);
5796
5797            let next_excerpt = cursor.item();
5798            let prev_excerpt = cursor.prev_item();
5799
5800            // Process all of the anchors for this excerpt.
5801            while let Some((anchor_ix, &anchor)) =
5802                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5803            {
5804                let mut anchor = anchor;
5805
5806                // Leave min and max anchors unchanged if invalid or
5807                // if the old excerpt still exists at this location
5808                let mut kept_position = next_excerpt
5809                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5810                    || old_excerpt_id == ExcerptId::max()
5811                    || old_excerpt_id == ExcerptId::min();
5812
5813                // If the old excerpt no longer exists at this location, then attempt to
5814                // find an equivalent position for this anchor in an adjacent excerpt.
5815                if !kept_position {
5816                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5817                        if excerpt.contains(&anchor) {
5818                            anchor.excerpt_id = excerpt.id;
5819                            kept_position = true;
5820                            break;
5821                        }
5822                    }
5823                }
5824
5825                // If there's no adjacent excerpt that contains the anchor's position,
5826                // then report that the anchor has lost its position.
5827                if !kept_position {
5828                    anchor = if let Some(excerpt) = next_excerpt {
5829                        let mut text_anchor = excerpt
5830                            .range
5831                            .context
5832                            .start
5833                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5834                        if text_anchor
5835                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5836                            .is_gt()
5837                        {
5838                            text_anchor = excerpt.range.context.end;
5839                        }
5840                        Anchor::in_buffer(excerpt.id, text_anchor)
5841                    } else if let Some(excerpt) = prev_excerpt {
5842                        let mut text_anchor = excerpt
5843                            .range
5844                            .context
5845                            .end
5846                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5847                        if text_anchor
5848                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5849                            .is_lt()
5850                        {
5851                            text_anchor = excerpt.range.context.start;
5852                        }
5853                        Anchor::in_buffer(excerpt.id, text_anchor)
5854                    } else if anchor.text_anchor.bias == Bias::Left {
5855                        Anchor::min()
5856                    } else {
5857                        Anchor::max()
5858                    };
5859                }
5860
5861                result.push((anchor_ix, anchor, kept_position));
5862            }
5863        }
5864        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5865        result
5866    }
5867
5868    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5869        self.anchor_at(position, Bias::Left)
5870    }
5871
5872    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5873        self.anchor_at(position, Bias::Right)
5874    }
5875
5876    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5877        let offset = position.to_offset(self);
5878
5879        // Find the given position in the diff transforms. Determine the corresponding
5880        // offset in the excerpts, and whether the position is within a deleted hunk.
5881        let mut diff_transforms = self
5882            .diff_transforms
5883            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5884        diff_transforms.seek(&offset, Bias::Right);
5885
5886        if offset == diff_transforms.start().0
5887            && bias == Bias::Left
5888            && let Some(prev_item) = diff_transforms.prev_item()
5889            && let DiffTransform::DeletedHunk { .. } = prev_item
5890        {
5891            diff_transforms.prev();
5892        }
5893        let offset_in_transform = offset - diff_transforms.start().0;
5894        let mut excerpt_offset = diff_transforms.start().1;
5895        let mut diff_base_anchor = None;
5896        if let Some(DiffTransform::DeletedHunk {
5897            buffer_id,
5898            base_text_byte_range,
5899            has_trailing_newline,
5900            ..
5901        }) = diff_transforms.item()
5902        {
5903            let diff = self.diffs.get(buffer_id).expect("missing diff");
5904            if offset_in_transform > base_text_byte_range.len() {
5905                debug_assert!(*has_trailing_newline);
5906                bias = Bias::Right;
5907            } else {
5908                diff_base_anchor = Some(
5909                    diff.base_text()
5910                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5911                );
5912                bias = Bias::Left;
5913            }
5914        } else {
5915            excerpt_offset += MultiBufferOffset(offset_in_transform);
5916        };
5917
5918        let mut excerpts = self
5919            .excerpts
5920            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5921        excerpts.seek(&excerpt_offset, Bias::Right);
5922        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5923            excerpts.prev();
5924        }
5925        if let Some(excerpt) = excerpts.item() {
5926            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5927            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5928                overshoot -= 1;
5929                bias = Bias::Right;
5930            }
5931
5932            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5933            let text_anchor =
5934                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5935            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5936            match diff_base_anchor {
5937                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5938                None => anchor,
5939            }
5940        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5941        {
5942            Anchor::min()
5943        } else {
5944            Anchor::max()
5945        }
5946    }
5947
5948    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5949    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5950        let (excerpt, buffer, _) = self.as_singleton()?;
5951        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5952            Some(Anchor::in_buffer(excerpt, text_anchor))
5953        } else {
5954            None
5955        }
5956    }
5957
5958    /// Returns an anchor for the given excerpt and text anchor,
5959    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5960    pub fn anchor_range_in_excerpt(
5961        &self,
5962        excerpt_id: ExcerptId,
5963        text_anchor: Range<text::Anchor>,
5964    ) -> Option<Range<Anchor>> {
5965        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5966
5967        Some(
5968            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5969                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5970        )
5971    }
5972
5973    /// Returns an anchor for the given excerpt and text anchor,
5974    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5975    pub fn anchor_in_excerpt(
5976        &self,
5977        excerpt_id: ExcerptId,
5978        text_anchor: text::Anchor,
5979    ) -> Option<Anchor> {
5980        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5981        Self::anchor_in_excerpt_(excerpt, text_anchor)
5982    }
5983
5984    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5985    pub fn anchors_in_excerpt(
5986        &self,
5987        excerpt_id: ExcerptId,
5988        text_anchors: impl IntoIterator<Item = text::Anchor>,
5989    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5990        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5991        Some(
5992            text_anchors
5993                .into_iter()
5994                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5995        )
5996    }
5997
5998    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5999        match text_anchor.buffer_id {
6000            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
6001            Some(_) => return None,
6002            None if text_anchor.is_max() || text_anchor.is_min() => {
6003                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
6004            }
6005            None => return None,
6006        }
6007
6008        let context = &excerpt.range.context;
6009        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6010            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6011        {
6012            return None;
6013        }
6014
6015        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6016    }
6017
6018    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6019        Some(self.excerpt(excerpt_id)?.range.context.clone())
6020    }
6021
6022    pub fn excerpt_range_for_excerpt(
6023        &self,
6024        excerpt_id: ExcerptId,
6025    ) -> Option<ExcerptRange<text::Anchor>> {
6026        Some(self.excerpt(excerpt_id)?.range.clone())
6027    }
6028
6029    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6030        if anchor.is_min() || anchor.is_max() {
6031            // todo(lw): should be `!self.is_empty()`
6032            true
6033        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6034            excerpt.buffer.can_resolve(&anchor.text_anchor)
6035        } else {
6036            false
6037        }
6038    }
6039
6040    pub fn excerpts(
6041        &self,
6042    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6043        self.excerpts
6044            .iter()
6045            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6046    }
6047
6048    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6049    where
6050        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6051        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6052    {
6053        let excerpts = self.excerpts.cursor(());
6054        let diff_transforms = self.diff_transforms.cursor(());
6055        MultiBufferCursor {
6056            excerpts,
6057            diff_transforms,
6058            diffs: &self.diffs,
6059            cached_region: OnceCell::new(),
6060        }
6061    }
6062
6063    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6064        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6065        let mut excerpts = self
6066            .excerpts
6067            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6068        excerpts.seek(&Some(start_locator), Bias::Left);
6069        excerpts.prev();
6070
6071        let mut diff_transforms = self
6072            .diff_transforms
6073            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6074        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6075        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6076            diff_transforms.next();
6077        }
6078
6079        let excerpt = excerpts.item()?;
6080        Some(MultiBufferExcerpt {
6081            excerpt,
6082            offset: diff_transforms.start().output_dimension.0,
6083            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6084            excerpt_offset: excerpts.start().1,
6085            diff_transforms,
6086        })
6087    }
6088
6089    pub fn excerpt_boundaries_in_range<R, T>(
6090        &self,
6091        range: R,
6092    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6093    where
6094        R: RangeBounds<T>,
6095        T: ToOffset,
6096    {
6097        let start_offset;
6098        let start = match range.start_bound() {
6099            Bound::Included(start) => {
6100                start_offset = start.to_offset(self);
6101                Bound::Included(start_offset)
6102            }
6103            Bound::Excluded(_) => {
6104                panic!("not supported")
6105            }
6106            Bound::Unbounded => {
6107                start_offset = MultiBufferOffset::ZERO;
6108                Bound::Unbounded
6109            }
6110        };
6111        let end = match range.end_bound() {
6112            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6113            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6114            Bound::Unbounded => Bound::Unbounded,
6115        };
6116        let bounds = (start, end);
6117        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6118        cursor.seek(&DimensionPair {
6119            key: start_offset,
6120            value: None,
6121        });
6122
6123        if cursor
6124            .fetch_excerpt_with_range()
6125            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6126        {
6127            cursor.prev_excerpt();
6128        } else {
6129            cursor.seek_to_start_of_current_excerpt();
6130        }
6131        let mut prev_region = cursor
6132            .fetch_excerpt_with_range()
6133            .map(|(excerpt, _)| excerpt);
6134
6135        cursor.next_excerpt_forwards();
6136
6137        iter::from_fn(move || {
6138            loop {
6139                if self.singleton {
6140                    return None;
6141                }
6142
6143                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6144                cursor.next_excerpt_forwards();
6145                if !bounds.contains(&next_range.start.key) {
6146                    prev_region = Some(next_excerpt);
6147                    continue;
6148                }
6149
6150                let next_region_start = next_range.start.value.unwrap();
6151                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6152                    range.start.value.unwrap()
6153                } else {
6154                    self.max_point()
6155                };
6156
6157                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6158                    id: region.id,
6159                    buffer: region.buffer.clone(),
6160                    buffer_id: region.buffer_id,
6161                    range: region.range.clone(),
6162                    end_row: MultiBufferRow(next_region_start.row),
6163                });
6164
6165                let next = ExcerptInfo {
6166                    id: next_excerpt.id,
6167                    buffer: next_excerpt.buffer.clone(),
6168                    buffer_id: next_excerpt.buffer_id,
6169                    range: next_excerpt.range.clone(),
6170                    end_row: if next_excerpt.has_trailing_newline {
6171                        MultiBufferRow(next_region_end.row - 1)
6172                    } else {
6173                        MultiBufferRow(next_region_end.row)
6174                    },
6175                };
6176
6177                let row = MultiBufferRow(next_region_start.row);
6178
6179                prev_region = Some(next_excerpt);
6180
6181                return Some(ExcerptBoundary { row, prev, next });
6182            }
6183        })
6184    }
6185
6186    pub fn edit_count(&self) -> usize {
6187        self.edit_count
6188    }
6189
6190    pub fn non_text_state_update_count(&self) -> usize {
6191        self.non_text_state_update_count
6192    }
6193
6194    /// Returns the smallest enclosing bracket ranges containing the given range or
6195    /// None if no brackets contain range or the range is not contained in a single
6196    /// excerpt
6197    ///
6198    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6199    #[ztracing::instrument(skip_all)]
6200    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6201        &self,
6202        range: Range<T>,
6203        range_filter: Option<
6204            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6205        >,
6206    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6207        let range = range.start.to_offset(self)..range.end.to_offset(self);
6208        let mut excerpt = self.excerpt_containing(range.clone())?;
6209        let buffer = excerpt.buffer();
6210        let excerpt_buffer_range = excerpt.buffer_range();
6211
6212        // Filter to ranges contained in the excerpt
6213        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6214            excerpt_buffer_range.contains(&BufferOffset(open.start))
6215                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6216                && range_filter.is_none_or(|filter| {
6217                    filter(
6218                        buffer,
6219                        BufferOffset(open.start)..BufferOffset(close.end),
6220                        BufferOffset(close.start)..BufferOffset(close.end),
6221                    )
6222                })
6223        };
6224
6225        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6226            excerpt.map_range_to_buffer(range),
6227            Some(&range_filter),
6228        )?;
6229
6230        Some((
6231            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6232            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6233        ))
6234    }
6235
6236    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6237    /// not contained in a single excerpt
6238    pub fn enclosing_bracket_ranges<T: ToOffset>(
6239        &self,
6240        range: Range<T>,
6241    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6242    {
6243        let range = range.start.to_offset(self)..range.end.to_offset(self);
6244        let mut excerpt = self.excerpt_containing(range.clone())?;
6245
6246        Some(
6247            excerpt
6248                .buffer()
6249                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6250                .filter_map(move |pair| {
6251                    let open_range =
6252                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6253                    let close_range =
6254                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6255                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6256                        Some((
6257                            excerpt.map_range_from_buffer(open_range),
6258                            excerpt.map_range_from_buffer(close_range),
6259                        ))
6260                    } else {
6261                        None
6262                    }
6263                }),
6264        )
6265    }
6266
6267    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6268    /// not contained in a single excerpt
6269    pub fn text_object_ranges<T: ToOffset>(
6270        &self,
6271        range: Range<T>,
6272        options: TreeSitterOptions,
6273    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6274        let range = range.start.to_offset(self)..range.end.to_offset(self);
6275        self.excerpt_containing(range.clone())
6276            .map(|mut excerpt| {
6277                excerpt
6278                    .buffer()
6279                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6280                    .filter_map(move |(range, text_object)| {
6281                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6282                        if excerpt.contains_buffer_range(range.clone()) {
6283                            Some((excerpt.map_range_from_buffer(range), text_object))
6284                        } else {
6285                            None
6286                        }
6287                    })
6288            })
6289            .into_iter()
6290            .flatten()
6291    }
6292
6293    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6294    /// not contained in a single excerpt
6295    pub fn bracket_ranges<T: ToOffset>(
6296        &self,
6297        range: Range<T>,
6298    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6299    {
6300        let range = range.start.to_offset(self)..range.end.to_offset(self);
6301        let mut excerpt = self.excerpt_containing(range.clone())?;
6302        Some(
6303            excerpt
6304                .buffer()
6305                .bracket_ranges(excerpt.map_range_to_buffer(range))
6306                .filter_map(move |pair| {
6307                    let open_range =
6308                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6309                    let close_range =
6310                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6311                    excerpt
6312                        .contains_buffer_range(open_range.start..close_range.end)
6313                        .then(|| BracketMatch {
6314                            open_range: excerpt.map_range_from_buffer(open_range),
6315                            close_range: excerpt.map_range_from_buffer(close_range),
6316                            color_index: pair.color_index,
6317                            newline_only: pair.newline_only,
6318                            syntax_layer_depth: pair.syntax_layer_depth,
6319                        })
6320                })
6321                .map(BracketMatch::bracket_ranges),
6322        )
6323    }
6324
6325    pub fn redacted_ranges<'a, T: ToOffset>(
6326        &'a self,
6327        range: Range<T>,
6328        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6329    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6330        let range = range.start.to_offset(self)..range.end.to_offset(self);
6331        self.lift_buffer_metadata(range, move |buffer, range| {
6332            if redaction_enabled(buffer.file()) {
6333                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6334            } else {
6335                None
6336            }
6337        })
6338        .map(|(range, _, _)| range)
6339    }
6340
6341    pub fn runnable_ranges(
6342        &self,
6343        range: Range<Anchor>,
6344    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6345        let range = range.start.to_offset(self)..range.end.to_offset(self);
6346        self.lift_buffer_metadata(range, move |buffer, range| {
6347            Some(
6348                buffer
6349                    .runnable_ranges(range.clone())
6350                    .filter(move |runnable| {
6351                        runnable.run_range.start >= range.start
6352                            && runnable.run_range.end < range.end
6353                    })
6354                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6355            )
6356        })
6357        .map(|(run_range, runnable, _)| (run_range, runnable))
6358    }
6359
6360    pub fn line_indents(
6361        &self,
6362        start_row: MultiBufferRow,
6363        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6364    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6365        let max_point = self.max_point();
6366        let mut cursor = self.cursor::<Point, Point>();
6367        cursor.seek(&Point::new(start_row.0, 0));
6368        iter::from_fn(move || {
6369            let mut region = cursor.region()?;
6370            while !buffer_filter(&region.excerpt.buffer) {
6371                cursor.next();
6372                region = cursor.region()?;
6373            }
6374            let region = cursor.region()?;
6375            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6376            let buffer_start_row =
6377                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6378
6379            let buffer_end_row = if region.is_main_buffer
6380                && (region.has_trailing_newline || region.range.end == max_point)
6381            {
6382                region.buffer_range.end.row
6383            } else {
6384                region.buffer_range.end.row.saturating_sub(1)
6385            };
6386
6387            let line_indents = region
6388                .buffer
6389                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6390            let region_buffer_row = region.buffer_range.start.row;
6391            let region_row = region.range.start.row;
6392            let region_buffer = &region.excerpt.buffer;
6393            cursor.next();
6394            Some(line_indents.map(move |(buffer_row, indent)| {
6395                let row = region_row + (buffer_row - region_buffer_row);
6396                (MultiBufferRow(row), indent, region_buffer.as_ref())
6397            }))
6398        })
6399        .flatten()
6400    }
6401
6402    pub fn reversed_line_indents(
6403        &self,
6404        end_row: MultiBufferRow,
6405        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6406    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6407        let max_point = self.max_point();
6408        let mut cursor = self.cursor::<Point, Point>();
6409        cursor.seek(&Point::new(end_row.0, 0));
6410        iter::from_fn(move || {
6411            let mut region = cursor.region()?;
6412            while !buffer_filter(&region.excerpt.buffer) {
6413                cursor.prev();
6414                region = cursor.region()?;
6415            }
6416            let region = cursor.region()?;
6417
6418            let buffer_start_row = region.buffer_range.start.row;
6419            let buffer_end_row = if region.is_main_buffer
6420                && (region.has_trailing_newline || region.range.end == max_point)
6421            {
6422                region.buffer_range.end.row + 1
6423            } else {
6424                region.buffer_range.end.row
6425            };
6426
6427            let overshoot = end_row.0 - region.range.start.row;
6428            let buffer_end_row =
6429                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6430
6431            let line_indents = region
6432                .buffer
6433                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6434            let region_buffer_row = region.buffer_range.start.row;
6435            let region_row = region.range.start.row;
6436            let region_buffer = &region.excerpt.buffer;
6437            cursor.prev();
6438            Some(line_indents.map(move |(buffer_row, indent)| {
6439                let row = region_row + (buffer_row - region_buffer_row);
6440                (MultiBufferRow(row), indent, region_buffer.as_ref())
6441            }))
6442        })
6443        .flatten()
6444    }
6445
6446    pub async fn enclosing_indent(
6447        &self,
6448        mut target_row: MultiBufferRow,
6449    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6450        let max_row = MultiBufferRow(self.max_point().row);
6451        if target_row >= max_row {
6452            return None;
6453        }
6454
6455        let mut target_indent = self.line_indent_for_row(target_row);
6456
6457        // If the current row is at the start of an indented block, we want to return this
6458        // block as the enclosing indent.
6459        if !target_indent.is_line_empty() && target_row < max_row {
6460            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6461            if !next_line_indent.is_line_empty()
6462                && target_indent.raw_len() < next_line_indent.raw_len()
6463            {
6464                target_indent = next_line_indent;
6465                target_row.0 += 1;
6466            }
6467        }
6468
6469        const SEARCH_ROW_LIMIT: u32 = 25000;
6470        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6471        const YIELD_INTERVAL: u32 = 100;
6472
6473        let mut accessed_row_counter = 0;
6474
6475        // If there is a blank line at the current row, search for the next non indented lines
6476        if target_indent.is_line_empty() {
6477            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6478            let end =
6479                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6480
6481            let mut non_empty_line_above = None;
6482            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6483                if row < start {
6484                    break;
6485                }
6486                accessed_row_counter += 1;
6487                if accessed_row_counter == YIELD_INTERVAL {
6488                    accessed_row_counter = 0;
6489                    yield_now().await;
6490                }
6491                if !indent.is_line_empty() {
6492                    non_empty_line_above = Some((row, indent));
6493                    break;
6494                }
6495            }
6496
6497            let mut non_empty_line_below = None;
6498            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6499                if row > end {
6500                    break;
6501                }
6502                accessed_row_counter += 1;
6503                if accessed_row_counter == YIELD_INTERVAL {
6504                    accessed_row_counter = 0;
6505                    yield_now().await;
6506                }
6507                if !indent.is_line_empty() {
6508                    non_empty_line_below = Some((row, indent));
6509                    break;
6510                }
6511            }
6512
6513            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6514                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6515                    if above_indent.raw_len() >= below_indent.raw_len() {
6516                        (above_row, above_indent)
6517                    } else {
6518                        (below_row, below_indent)
6519                    }
6520                }
6521                (Some(above), None) => above,
6522                (None, Some(below)) => below,
6523                _ => return None,
6524            };
6525
6526            target_indent = indent;
6527            target_row = row;
6528        }
6529
6530        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6531        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6532
6533        let mut start_indent = None;
6534        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6535            if row < start {
6536                break;
6537            }
6538            accessed_row_counter += 1;
6539            if accessed_row_counter == YIELD_INTERVAL {
6540                accessed_row_counter = 0;
6541                yield_now().await;
6542            }
6543            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6544                start_indent = Some((row, indent));
6545                break;
6546            }
6547        }
6548        let (start_row, start_indent_size) = start_indent?;
6549
6550        let mut end_indent = (end, None);
6551        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6552            if row > end {
6553                break;
6554            }
6555            accessed_row_counter += 1;
6556            if accessed_row_counter == YIELD_INTERVAL {
6557                accessed_row_counter = 0;
6558                yield_now().await;
6559            }
6560            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6561                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6562                break;
6563            }
6564        }
6565        let (end_row, end_indent_size) = end_indent;
6566
6567        let indent = if let Some(end_indent_size) = end_indent_size {
6568            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6569                start_indent_size
6570            } else {
6571                end_indent_size
6572            }
6573        } else {
6574            start_indent_size
6575        };
6576
6577        Some((start_row..end_row, indent))
6578    }
6579
6580    pub fn indent_guides_in_range<T: ToPoint>(
6581        &self,
6582        range: Range<T>,
6583        ignore_disabled_for_language: bool,
6584        cx: &App,
6585    ) -> impl Iterator<Item = IndentGuide> {
6586        let range = range.start.to_point(self)..range.end.to_point(self);
6587        let start_row = MultiBufferRow(range.start.row);
6588        let end_row = MultiBufferRow(range.end.row);
6589
6590        let mut row_indents = self.line_indents(start_row, |buffer| {
6591            let settings = LanguageSettings::for_buffer_snapshot(buffer, None, cx);
6592            settings.indent_guides.enabled || ignore_disabled_for_language
6593        });
6594
6595        let mut result = Vec::new();
6596        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6597
6598        let mut prev_settings = None;
6599        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6600            if first_row > end_row {
6601                break;
6602            }
6603            let current_depth = indent_stack.len() as u32;
6604
6605            // Avoid retrieving the language settings repeatedly for every buffer row.
6606            if let Some((prev_buffer_id, _)) = &prev_settings
6607                && prev_buffer_id != &buffer.remote_id()
6608            {
6609                prev_settings.take();
6610            }
6611            let settings = &prev_settings
6612                .get_or_insert_with(|| {
6613                    (
6614                        buffer.remote_id(),
6615                        LanguageSettings::for_buffer_snapshot(buffer, None, cx),
6616                    )
6617                })
6618                .1;
6619            let tab_size = settings.tab_size.get();
6620
6621            // When encountering empty, continue until found useful line indent
6622            // then add to the indent stack with the depth found
6623            let mut found_indent = false;
6624            let mut last_row = first_row;
6625            if line_indent.is_line_blank() {
6626                while !found_indent {
6627                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6628                        break;
6629                    };
6630                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6631                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6632                        break;
6633                    }
6634
6635                    if new_line_indent.is_line_blank() {
6636                        continue;
6637                    }
6638                    last_row = target_row.min(end_row);
6639                    line_indent = new_line_indent;
6640                    found_indent = true;
6641                    break;
6642                }
6643            } else {
6644                found_indent = true
6645            }
6646
6647            let depth = if found_indent {
6648                line_indent.len(tab_size) / tab_size
6649            } else {
6650                0
6651            };
6652
6653            match depth.cmp(&current_depth) {
6654                cmp::Ordering::Less => {
6655                    for _ in 0..(current_depth - depth) {
6656                        let mut indent = indent_stack.pop().unwrap();
6657                        if last_row != first_row {
6658                            // In this case, we landed on an empty row, had to seek forward,
6659                            // and discovered that the indent we where on is ending.
6660                            // This means that the last display row must
6661                            // be on line that ends this indent range, so we
6662                            // should display the range up to the first non-empty line
6663                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6664                        }
6665
6666                        result.push(indent)
6667                    }
6668                }
6669                cmp::Ordering::Greater => {
6670                    for next_depth in current_depth..depth {
6671                        indent_stack.push(IndentGuide {
6672                            buffer_id: buffer.remote_id(),
6673                            start_row: first_row,
6674                            end_row: last_row,
6675                            depth: next_depth,
6676                            tab_size,
6677                            settings: settings.indent_guides.clone(),
6678                        });
6679                    }
6680                }
6681                _ => {}
6682            }
6683
6684            for indent in indent_stack.iter_mut() {
6685                indent.end_row = last_row;
6686            }
6687        }
6688
6689        result.extend(indent_stack);
6690        result.into_iter()
6691    }
6692
6693    pub fn trailing_excerpt_update_count(&self) -> usize {
6694        self.trailing_excerpt_update_count
6695    }
6696
6697    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6698        self.point_to_buffer_offset(point)
6699            .and_then(|(buffer, _)| buffer.file())
6700    }
6701
6702    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6703        self.point_to_buffer_offset(offset)
6704            .and_then(|(buffer, offset)| buffer.language_at(offset))
6705    }
6706
6707    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6708        self.excerpts
6709            .first()
6710            .map(|excerpt| &excerpt.buffer)
6711            .map(|buffer| LanguageSettings::for_buffer_snapshot(buffer, None, cx))
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        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6721            buffer.settings_at(offset, cx)
6722        } else {
6723            Cow::Borrowed(&AllLanguageSettings::get_global(cx).defaults)
6724        }
6725    }
6726
6727    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6728        self.point_to_buffer_offset(point)
6729            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6730    }
6731
6732    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6733        self.point_to_buffer_offset(point)
6734            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6735            .unwrap_or_default()
6736    }
6737
6738    pub fn language_indent_size_at<T: ToOffset>(
6739        &self,
6740        position: T,
6741        cx: &App,
6742    ) -> Option<IndentSize> {
6743        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6744        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6745    }
6746
6747    pub fn is_dirty(&self) -> bool {
6748        self.is_dirty
6749    }
6750
6751    pub fn has_deleted_file(&self) -> bool {
6752        self.has_deleted_file
6753    }
6754
6755    pub fn has_conflict(&self) -> bool {
6756        self.has_conflict
6757    }
6758
6759    pub fn has_diagnostics(&self) -> bool {
6760        self.excerpts
6761            .iter()
6762            .any(|excerpt| excerpt.buffer.has_diagnostics())
6763    }
6764
6765    pub fn diagnostic_group(
6766        &self,
6767        buffer_id: BufferId,
6768        group_id: usize,
6769    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6770        self.lift_buffer_metadata::<Point, _, _>(
6771            Point::zero()..self.max_point(),
6772            move |buffer, range| {
6773                if buffer.remote_id() != buffer_id {
6774                    return None;
6775                };
6776                Some(
6777                    buffer
6778                        .diagnostics_in_range(range, false)
6779                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6780                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6781                )
6782            },
6783        )
6784        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6785    }
6786
6787    pub fn diagnostics_in_range<'a, MBD>(
6788        &'a self,
6789        range: Range<MBD>,
6790    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6791    where
6792        MBD::TextDimension: 'a
6793            + text::ToOffset
6794            + text::FromAnchor
6795            + Sub<Output = MBD::TextDimension>
6796            + fmt::Debug
6797            + ops::Add<Output = MBD::TextDimension>
6798            + ops::AddAssign
6799            + Ord,
6800        MBD: MultiBufferDimension
6801            + Ord
6802            + Sub<Output = MBD::TextDimension>
6803            + ops::Add<MBD::TextDimension, Output = MBD>
6804            + ops::AddAssign<MBD::TextDimension>
6805            + 'a,
6806    {
6807        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6808            Some(
6809                buffer
6810                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6811                    .map(|entry| (entry.range, entry.diagnostic)),
6812            )
6813        })
6814        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6815    }
6816
6817    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6818        &'a self,
6819        range: Range<MBD>,
6820    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6821    where
6822        MBD: MultiBufferDimension
6823            + Ord
6824            + Sub<Output = MBD::TextDimension>
6825            + ops::Add<MBD::TextDimension, Output = MBD>
6826            + ops::AddAssign<MBD::TextDimension>,
6827        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6828            + ops::Add<Output = MBD::TextDimension>
6829            + text::ToOffset
6830            + text::FromAnchor
6831            + AddAssign<MBD::TextDimension>
6832            + Ord,
6833    {
6834        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6835            Some(
6836                buffer
6837                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6838                    .map(|entry| (entry.range, entry.diagnostic)),
6839            )
6840        })
6841        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6842    }
6843
6844    pub fn syntax_ancestor<T: ToOffset>(
6845        &self,
6846        range: Range<T>,
6847    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6848        let range = range.start.to_offset(self)..range.end.to_offset(self);
6849        let mut excerpt = self.excerpt_containing(range.clone())?;
6850        let node = excerpt
6851            .buffer()
6852            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6853        let node_range = node.byte_range();
6854        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6855        if !excerpt.contains_buffer_range(node_range.clone()) {
6856            return None;
6857        };
6858        Some((node, excerpt.map_range_from_buffer(node_range)))
6859    }
6860
6861    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6862        let (excerpt_id, _, buffer) = self.as_singleton()?;
6863        let outline = buffer.outline(theme);
6864        Some(Outline::new(
6865            outline
6866                .items
6867                .into_iter()
6868                .flat_map(|item| {
6869                    Some(OutlineItem {
6870                        depth: item.depth,
6871                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6872                        source_range_for_text: self
6873                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6874                        text: item.text,
6875                        highlight_ranges: item.highlight_ranges,
6876                        name_ranges: item.name_ranges,
6877                        body_range: item.body_range.and_then(|body_range| {
6878                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6879                        }),
6880                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6881                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6882                        }),
6883                    })
6884                })
6885                .collect(),
6886        ))
6887    }
6888
6889    pub fn symbols_containing<T: ToOffset>(
6890        &self,
6891        offset: T,
6892        theme: Option<&SyntaxTheme>,
6893    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6894        let anchor = self.anchor_before(offset);
6895        let excerpt @ &Excerpt {
6896            id: excerpt_id,
6897            buffer_id,
6898            ref buffer,
6899            ..
6900        } = self.excerpt(anchor.excerpt_id)?;
6901        if cfg!(debug_assertions) {
6902            match anchor.text_anchor.buffer_id {
6903                // we clearly are hitting this according to sentry, but in what situations can this occur?
6904                Some(anchor_buffer_id) => {
6905                    assert_eq!(
6906                        anchor_buffer_id, buffer_id,
6907                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6908                    )
6909                }
6910                None => assert!(anchor.is_max()),
6911            }
6912        };
6913        Some((
6914            buffer_id,
6915            buffer
6916                .symbols_containing(anchor.text_anchor, theme)
6917                .into_iter()
6918                .flat_map(|item| {
6919                    Some(OutlineItem {
6920                        depth: item.depth,
6921                        source_range_for_text: Anchor::range_in_buffer(
6922                            excerpt_id,
6923                            item.source_range_for_text,
6924                        ),
6925                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6926                        text: item.text,
6927                        highlight_ranges: item.highlight_ranges,
6928                        name_ranges: item.name_ranges,
6929                        body_range: item
6930                            .body_range
6931                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6932                        annotation_range: item
6933                            .annotation_range
6934                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6935                    })
6936                })
6937                .collect(),
6938        ))
6939    }
6940
6941    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6942        self.try_excerpt_locator_for_id(id)
6943            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6944    }
6945
6946    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6947        if id == ExcerptId::min() {
6948            Some(Locator::min_ref())
6949        } else if id == ExcerptId::max() {
6950            Some(Locator::max_ref())
6951        } else {
6952            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6953            if let Some(entry) = item
6954                && entry.id == id
6955            {
6956                return Some(&entry.locator);
6957            }
6958            None
6959        }
6960    }
6961
6962    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6963    fn excerpt_locators_for_ids(
6964        &self,
6965        ids: impl IntoIterator<Item = ExcerptId>,
6966    ) -> SmallVec<[Locator; 1]> {
6967        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6968        sorted_ids.sort_unstable();
6969        sorted_ids.dedup();
6970        let mut locators = SmallVec::new();
6971
6972        while sorted_ids.last() == Some(&ExcerptId::max()) {
6973            sorted_ids.pop();
6974            locators.push(Locator::max());
6975        }
6976
6977        let mut sorted_ids = sorted_ids.into_iter().peekable();
6978        locators.extend(
6979            sorted_ids
6980                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6981                .map(|_| Locator::min()),
6982        );
6983
6984        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6985        for id in sorted_ids {
6986            if cursor.seek_forward(&id, Bias::Left) {
6987                locators.push(cursor.item().unwrap().locator.clone());
6988            } else {
6989                panic!("invalid excerpt id {:?}", id);
6990            }
6991        }
6992
6993        locators.sort_unstable();
6994        locators
6995    }
6996
6997    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6998        Some(self.excerpt(excerpt_id)?.buffer_id)
6999    }
7000
7001    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7002        Some(&self.excerpt(excerpt_id)?.buffer)
7003    }
7004
7005    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7006        let mut cursor = self
7007            .excerpts
7008            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7009        let locator = self.excerpt_locator_for_id(excerpt_id);
7010        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7011        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7012            sought_exact = true;
7013            cursor.prev();
7014        } else if excerpt_id == ExcerptId::min() {
7015            sought_exact = true;
7016        }
7017        if sought_exact {
7018            let start = cursor.start().1;
7019            let end = cursor.end().1;
7020            let mut diff_transforms = self
7021                .diff_transforms
7022                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7023            diff_transforms.seek(&start, Bias::Left);
7024            let overshoot = start - diff_transforms.start().0;
7025            let start = diff_transforms.start().1 + overshoot;
7026            diff_transforms.seek(&end, Bias::Right);
7027            let overshoot = end - diff_transforms.start().0;
7028            let end = diff_transforms.start().1 + overshoot;
7029            Some(start.0..end.0)
7030        } else {
7031            None
7032        }
7033    }
7034
7035    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7036    /// to have the latest excerpt id for the one passed in and will also remap
7037    /// `ExcerptId::max()` to the corresponding excertp ID.
7038    ///
7039    /// Callers of this function should generally use the resulting excerpt's `id` field
7040    /// afterwards.
7041    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7042        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7043        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7044        let (_, _, item) =
7045            self.excerpts
7046                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7047        if let Some(excerpt) = item
7048            && excerpt.id == excerpt_id
7049        {
7050            return Some(excerpt);
7051        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7052            return self.excerpts.last();
7053        }
7054        None
7055    }
7056
7057    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7058    pub fn excerpt_containing<T: ToOffset>(
7059        &self,
7060        range: Range<T>,
7061    ) -> Option<MultiBufferExcerpt<'_>> {
7062        let range = range.start.to_offset(self)..range.end.to_offset(self);
7063        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7064        cursor.seek(&range.start);
7065
7066        let start_excerpt = cursor.excerpt()?;
7067        if range.end != range.start {
7068            cursor.seek_forward(&range.end);
7069            if cursor.excerpt()?.id != start_excerpt.id {
7070                return None;
7071            }
7072        }
7073
7074        cursor.seek_to_start_of_current_excerpt();
7075        let region = cursor.region()?;
7076        let offset = region.range.start;
7077        let buffer_offset = start_excerpt.buffer_start_offset();
7078        let excerpt_offset = *cursor.excerpts.start();
7079        Some(MultiBufferExcerpt {
7080            diff_transforms: cursor.diff_transforms,
7081            excerpt: start_excerpt,
7082            offset,
7083            buffer_offset,
7084            excerpt_offset,
7085        })
7086    }
7087
7088    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7089        if let Some(id) = anchor.text_anchor.buffer_id {
7090            return Some(id);
7091        }
7092        let excerpt = self.excerpt_containing(anchor..anchor)?;
7093        Some(excerpt.buffer_id())
7094    }
7095
7096    pub fn selections_in_range<'a>(
7097        &'a self,
7098        range: &'a Range<Anchor>,
7099        include_local: bool,
7100    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7101        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7102        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7103        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7104        cursor.seek(start_locator, Bias::Left);
7105        cursor
7106            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7107            .flat_map(move |excerpt| {
7108                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7109                if excerpt.id == range.start.excerpt_id {
7110                    query_range.start = range.start.text_anchor;
7111                }
7112                if excerpt.id == range.end.excerpt_id {
7113                    query_range.end = range.end.text_anchor;
7114                }
7115
7116                excerpt
7117                    .buffer
7118                    .selections_in_range(query_range, include_local)
7119                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7120                        selections.map(move |selection| {
7121                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7122                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7123                            if range.start.cmp(&start, self).is_gt() {
7124                                start = range.start;
7125                            }
7126                            if range.end.cmp(&end, self).is_lt() {
7127                                end = range.end;
7128                            }
7129
7130                            (
7131                                replica_id,
7132                                line_mode,
7133                                cursor_shape,
7134                                Selection {
7135                                    id: selection.id,
7136                                    start,
7137                                    end,
7138                                    reversed: selection.reversed,
7139                                    goal: selection.goal,
7140                                },
7141                            )
7142                        })
7143                    })
7144            })
7145    }
7146
7147    pub fn show_headers(&self) -> bool {
7148        self.show_headers
7149    }
7150
7151    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7152        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7153    }
7154
7155    pub fn all_diff_hunks_expanded(&self) -> bool {
7156        self.all_diff_hunks_expanded
7157    }
7158
7159    /// Visually annotates a position or range with the `Debug` representation of a value. The
7160    /// callsite of this function is used as a key - previous annotations will be removed.
7161    #[cfg(debug_assertions)]
7162    #[track_caller]
7163    pub fn debug<V, R>(&self, ranges: &R, value: V)
7164    where
7165        R: debug::ToMultiBufferDebugRanges,
7166        V: std::fmt::Debug,
7167    {
7168        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7169    }
7170
7171    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7172    /// debug annotations with the same key will be removed. The key is also used to determine the
7173    /// annotation's color.
7174    #[cfg(debug_assertions)]
7175    #[track_caller]
7176    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7177    where
7178        K: std::hash::Hash + 'static,
7179        R: debug::ToMultiBufferDebugRanges,
7180        V: std::fmt::Debug,
7181    {
7182        let text_ranges = ranges
7183            .to_multi_buffer_debug_ranges(self)
7184            .into_iter()
7185            .flat_map(|range| {
7186                self.range_to_buffer_ranges(range.start..=range.end)
7187                    .into_iter()
7188                    .map(|(buffer, range, _excerpt_id)| {
7189                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7190                    })
7191            })
7192            .collect();
7193        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7194            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7195        });
7196    }
7197
7198    fn excerpt_edits_for_diff_change(
7199        &self,
7200        buffer_state: &BufferState,
7201        diff_change_range: Range<usize>,
7202    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7203        let mut excerpt_edits = Vec::new();
7204        for locator in &buffer_state.excerpts {
7205            let mut cursor = self
7206                .excerpts
7207                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7208            cursor.seek_forward(&Some(locator), Bias::Left);
7209            if let Some(excerpt) = cursor.item()
7210                && excerpt.locator == *locator
7211            {
7212                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7213                if diff_change_range.end < excerpt_buffer_range.start
7214                    || diff_change_range.start > excerpt_buffer_range.end
7215                {
7216                    continue;
7217                }
7218                let excerpt_start = cursor.start().1;
7219                let excerpt_len = excerpt.text_summary.len;
7220                let diff_change_start_in_excerpt = diff_change_range
7221                    .start
7222                    .saturating_sub(excerpt_buffer_range.start);
7223                let diff_change_end_in_excerpt = diff_change_range
7224                    .end
7225                    .saturating_sub(excerpt_buffer_range.start);
7226                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7227                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7228                excerpt_edits.push(Edit {
7229                    old: edit_start..edit_end,
7230                    new: edit_start..edit_end,
7231                });
7232            }
7233        }
7234        excerpt_edits
7235    }
7236}
7237
7238#[cfg(any(test, feature = "test-support"))]
7239impl MultiBufferSnapshot {
7240    pub fn random_byte_range(
7241        &self,
7242        start_offset: MultiBufferOffset,
7243        rng: &mut impl rand::Rng,
7244    ) -> Range<MultiBufferOffset> {
7245        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7246        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7247        start..end
7248    }
7249
7250    #[cfg(any(test, feature = "test-support"))]
7251    fn check_invariants(&self) {
7252        let excerpts = self.excerpts.items(());
7253        let excerpt_ids = self.excerpt_ids.items(());
7254
7255        for (ix, excerpt) in excerpts.iter().enumerate() {
7256            if ix == 0 {
7257                if excerpt.locator <= Locator::min() {
7258                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7259                }
7260            } else if excerpt.locator <= excerpts[ix - 1].locator {
7261                panic!("excerpts are out-of-order: {:?}", excerpts);
7262            }
7263        }
7264
7265        for (ix, entry) in excerpt_ids.iter().enumerate() {
7266            if ix == 0 {
7267                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7268                    panic!("invalid first excerpt id {:?}", entry.id);
7269                }
7270            } else if entry.id <= excerpt_ids[ix - 1].id {
7271                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7272            }
7273        }
7274
7275        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7276            panic!(
7277                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7278                self.excerpts.summary().text,
7279                self.diff_transforms.summary().input,
7280                self.diff_transforms.items(()),
7281            );
7282        }
7283
7284        let mut prev_transform: Option<&DiffTransform> = None;
7285        for item in self.diff_transforms.iter() {
7286            if let DiffTransform::BufferContent {
7287                summary,
7288                inserted_hunk_info,
7289            } = item
7290            {
7291                if let Some(DiffTransform::BufferContent {
7292                    inserted_hunk_info: prev_inserted_hunk_info,
7293                    ..
7294                }) = prev_transform
7295                    && *inserted_hunk_info == *prev_inserted_hunk_info
7296                {
7297                    panic!(
7298                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7299                        self.diff_transforms.items(())
7300                    );
7301                }
7302                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7303                    panic!("empty buffer content transform");
7304                }
7305            }
7306            prev_transform = Some(item);
7307        }
7308    }
7309}
7310
7311impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7312where
7313    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7314    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7315{
7316    #[instrument(skip_all)]
7317    fn seek(&mut self, position: &MBD) {
7318        let position = OutputDimension(*position);
7319        self.cached_region.take();
7320        self.diff_transforms.seek(&position, Bias::Right);
7321        if self.diff_transforms.item().is_none()
7322            && self.diff_transforms.start().output_dimension == position
7323        {
7324            self.diff_transforms.prev();
7325        }
7326
7327        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7328        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7329            let overshoot = position - self.diff_transforms.start().output_dimension;
7330            excerpt_position += overshoot;
7331        }
7332
7333        self.excerpts.seek(&excerpt_position, Bias::Right);
7334        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7335            self.excerpts.prev();
7336        }
7337    }
7338
7339    fn seek_forward(&mut self, position: &MBD) {
7340        let position = OutputDimension(*position);
7341        self.cached_region.take();
7342        self.diff_transforms.seek_forward(&position, Bias::Right);
7343        if self.diff_transforms.item().is_none()
7344            && self.diff_transforms.start().output_dimension == position
7345        {
7346            self.diff_transforms.prev();
7347        }
7348
7349        let overshoot = position - self.diff_transforms.start().output_dimension;
7350        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7351        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7352            excerpt_position += overshoot;
7353        }
7354
7355        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7356        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7357            self.excerpts.prev();
7358        }
7359    }
7360
7361    fn next_excerpt(&mut self) {
7362        self.excerpts.next();
7363        self.seek_to_start_of_current_excerpt();
7364    }
7365
7366    fn prev_excerpt(&mut self) {
7367        self.excerpts.prev();
7368        self.seek_to_start_of_current_excerpt();
7369    }
7370
7371    fn seek_to_start_of_current_excerpt(&mut self) {
7372        self.cached_region.take();
7373
7374        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7375            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7376            && self.diff_transforms.next_item().is_some()
7377        {
7378            self.diff_transforms.next();
7379        }
7380    }
7381
7382    fn next_excerpt_forwards(&mut self) {
7383        self.excerpts.next();
7384        self.seek_to_start_of_current_excerpt_forward();
7385    }
7386
7387    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7388        self.cached_region.take();
7389
7390        if self
7391            .diff_transforms
7392            .seek_forward(self.excerpts.start(), Bias::Left)
7393            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7394            && self.diff_transforms.next_item().is_some()
7395        {
7396            self.diff_transforms.next();
7397        }
7398    }
7399
7400    fn next(&mut self) {
7401        self.cached_region.take();
7402        match self
7403            .diff_transforms
7404            .end()
7405            .excerpt_dimension
7406            .cmp(&self.excerpts.end())
7407        {
7408            cmp::Ordering::Less => self.diff_transforms.next(),
7409            cmp::Ordering::Greater => self.excerpts.next(),
7410            cmp::Ordering::Equal => {
7411                self.diff_transforms.next();
7412                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7413                    || self.diff_transforms.item().is_none()
7414                {
7415                    self.excerpts.next();
7416                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7417                    self.diff_transforms.item()
7418                    && self
7419                        .excerpts
7420                        .item()
7421                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7422                {
7423                    self.excerpts.next();
7424                }
7425            }
7426        }
7427    }
7428
7429    fn prev(&mut self) {
7430        self.cached_region.take();
7431        match self
7432            .diff_transforms
7433            .start()
7434            .excerpt_dimension
7435            .cmp(self.excerpts.start())
7436        {
7437            cmp::Ordering::Less => self.excerpts.prev(),
7438            cmp::Ordering::Greater => self.diff_transforms.prev(),
7439            cmp::Ordering::Equal => {
7440                self.diff_transforms.prev();
7441                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7442                    || self.diff_transforms.item().is_none()
7443                {
7444                    self.excerpts.prev();
7445                }
7446            }
7447        }
7448    }
7449
7450    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7451        self.cached_region
7452            .get_or_init(|| self.build_region())
7453            .as_ref()
7454    }
7455
7456    fn is_at_start_of_excerpt(&mut self) -> bool {
7457        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7458            return false;
7459        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7460            return true;
7461        }
7462
7463        self.diff_transforms.prev();
7464        let prev_transform = self.diff_transforms.item();
7465        self.diff_transforms.next();
7466
7467        prev_transform.is_none_or(|next_transform| {
7468            matches!(next_transform, DiffTransform::BufferContent { .. })
7469        })
7470    }
7471
7472    fn is_at_end_of_excerpt(&self) -> bool {
7473        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7474            return false;
7475        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7476            || self.diff_transforms.item().is_none()
7477        {
7478            return true;
7479        }
7480
7481        let next_transform = self.diff_transforms.next_item();
7482        next_transform.is_none_or(|next_transform| match next_transform {
7483            DiffTransform::BufferContent { .. } => true,
7484            DiffTransform::DeletedHunk { hunk_info, .. } => self
7485                .excerpts
7486                .item()
7487                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7488        })
7489    }
7490
7491    fn main_buffer_position(&self) -> Option<BD> {
7492        let excerpt = self.excerpts.item()?;
7493        let buffer = &excerpt.buffer;
7494        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7495        let mut buffer_start = buffer_context_start;
7496        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7497        buffer_start += overshoot;
7498        Some(buffer_start)
7499    }
7500
7501    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7502        let excerpt = self.excerpts.item()?;
7503        match self.diff_transforms.item()? {
7504            DiffTransform::DeletedHunk {
7505                buffer_id,
7506                base_text_byte_range,
7507                has_trailing_newline,
7508                hunk_info,
7509                ..
7510            } => {
7511                let diff = self.diffs.get(buffer_id)?;
7512                let buffer = diff.base_text();
7513                let mut rope_cursor = buffer.as_rope().cursor(0);
7514                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7515                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7516                let mut buffer_end = buffer_start;
7517                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7518                let start = self.diff_transforms.start().output_dimension.0;
7519                let end = self.diff_transforms.end().output_dimension.0;
7520                Some(MultiBufferRegion {
7521                    buffer,
7522                    excerpt,
7523                    has_trailing_newline: *has_trailing_newline,
7524                    is_main_buffer: false,
7525                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7526                        hunk_info.hunk_secondary_status,
7527                    )),
7528                    buffer_range: buffer_start..buffer_end,
7529                    range: start..end,
7530                })
7531            }
7532            DiffTransform::BufferContent {
7533                inserted_hunk_info, ..
7534            } => {
7535                let buffer = &excerpt.buffer;
7536                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7537
7538                let mut start = self.diff_transforms.start().output_dimension.0;
7539                let mut buffer_start = buffer_context_start;
7540                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7541                    let overshoot =
7542                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7543                    start += overshoot;
7544                } else {
7545                    let overshoot =
7546                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7547                    buffer_start += overshoot;
7548                }
7549
7550                let mut end;
7551                let mut buffer_end;
7552                let has_trailing_newline;
7553                let transform_end = self.diff_transforms.end();
7554                if transform_end.excerpt_dimension < self.excerpts.end() {
7555                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7556                    end = transform_end.output_dimension.0;
7557                    buffer_end = buffer_context_start;
7558                    buffer_end += overshoot;
7559                    has_trailing_newline = false;
7560                } else {
7561                    let overshoot =
7562                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7563                    end = self.diff_transforms.start().output_dimension.0;
7564                    end += overshoot;
7565                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7566                    has_trailing_newline = excerpt.has_trailing_newline;
7567                };
7568
7569                let diff_hunk_status = inserted_hunk_info.map(|info| {
7570                    if info.is_logically_deleted {
7571                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7572                    } else {
7573                        DiffHunkStatus::added(info.hunk_secondary_status)
7574                    }
7575                });
7576
7577                Some(MultiBufferRegion {
7578                    buffer,
7579                    excerpt,
7580                    has_trailing_newline,
7581                    is_main_buffer: true,
7582                    diff_hunk_status,
7583                    buffer_range: buffer_start..buffer_end,
7584                    range: start..end,
7585                })
7586            }
7587        }
7588    }
7589
7590    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7591        let excerpt = self.excerpts.item()?;
7592        match self.diff_transforms.item()? {
7593            &DiffTransform::DeletedHunk { .. } => {
7594                let start = self.diff_transforms.start().output_dimension.0;
7595                let end = self.diff_transforms.end().output_dimension.0;
7596                Some((excerpt, start..end))
7597            }
7598            DiffTransform::BufferContent { .. } => {
7599                let mut start = self.diff_transforms.start().output_dimension.0;
7600                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7601                    let overshoot =
7602                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7603                    start += overshoot;
7604                }
7605
7606                let mut end;
7607                let transform_end = self.diff_transforms.end();
7608                if transform_end.excerpt_dimension < self.excerpts.end() {
7609                    end = transform_end.output_dimension.0;
7610                } else {
7611                    let overshoot =
7612                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7613                    end = self.diff_transforms.start().output_dimension.0;
7614                    end += overshoot;
7615                };
7616
7617                Some((excerpt, start..end))
7618            }
7619        }
7620    }
7621
7622    fn excerpt(&self) -> Option<&'a Excerpt> {
7623        self.excerpts.item()
7624    }
7625}
7626
7627impl Excerpt {
7628    fn new(
7629        id: ExcerptId,
7630        locator: Locator,
7631        buffer_id: BufferId,
7632        buffer: Arc<BufferSnapshot>,
7633        range: ExcerptRange<text::Anchor>,
7634        has_trailing_newline: bool,
7635    ) -> Self {
7636        Excerpt {
7637            id,
7638            locator,
7639            max_buffer_row: range.context.end.to_point(&buffer).row,
7640            text_summary: buffer
7641                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7642            buffer_id,
7643            buffer,
7644            range,
7645            has_trailing_newline,
7646        }
7647    }
7648
7649    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7650        let content_start = self.range.context.start.to_offset(&self.buffer);
7651        let chunks_start = content_start + range.start;
7652        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7653
7654        let has_footer = self.has_trailing_newline
7655            && range.start <= self.text_summary.len
7656            && range.end > self.text_summary.len;
7657
7658        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7659
7660        ExcerptChunks {
7661            excerpt_id: self.id,
7662            content_chunks,
7663            has_footer,
7664        }
7665    }
7666
7667    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7668        let content_start = self.range.context.start.to_offset(&self.buffer);
7669        let chunks_start = content_start + range.start;
7670        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7671        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7672        excerpt_chunks.has_footer = self.has_trailing_newline
7673            && range.start <= self.text_summary.len
7674            && range.end > self.text_summary.len;
7675    }
7676
7677    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7678        if text_anchor
7679            .cmp(&self.range.context.start, &self.buffer)
7680            .is_lt()
7681        {
7682            self.range.context.start
7683        } else if text_anchor
7684            .cmp(&self.range.context.end, &self.buffer)
7685            .is_gt()
7686        {
7687            self.range.context.end
7688        } else {
7689            text_anchor
7690        }
7691    }
7692
7693    fn contains(&self, anchor: &Anchor) -> bool {
7694        (anchor.text_anchor.buffer_id == None
7695            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7696            && self
7697                .range
7698                .context
7699                .start
7700                .cmp(&anchor.text_anchor, &self.buffer)
7701                .is_le()
7702            && self
7703                .range
7704                .context
7705                .end
7706                .cmp(&anchor.text_anchor, &self.buffer)
7707                .is_ge()
7708    }
7709
7710    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7711    fn buffer_start_offset(&self) -> BufferOffset {
7712        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7713    }
7714
7715    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7716    fn buffer_end_offset(&self) -> BufferOffset {
7717        self.buffer_start_offset() + self.text_summary.len
7718    }
7719}
7720
7721impl<'a> MultiBufferExcerpt<'a> {
7722    pub fn id(&self) -> ExcerptId {
7723        self.excerpt.id
7724    }
7725
7726    pub fn buffer_id(&self) -> BufferId {
7727        self.excerpt.buffer_id
7728    }
7729
7730    pub fn start_anchor(&self) -> Anchor {
7731        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7732    }
7733
7734    pub fn end_anchor(&self) -> Anchor {
7735        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7736    }
7737
7738    pub fn buffer(&self) -> &'a BufferSnapshot {
7739        &self.excerpt.buffer
7740    }
7741
7742    pub fn buffer_range(&self) -> Range<BufferOffset> {
7743        self.buffer_offset
7744            ..BufferOffset(
7745                self.excerpt
7746                    .range
7747                    .context
7748                    .end
7749                    .to_offset(&self.excerpt.buffer.text),
7750            )
7751    }
7752
7753    pub fn start_offset(&self) -> MultiBufferOffset {
7754        self.offset
7755    }
7756
7757    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7758    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7759        self.map_range_to_buffer(offset..offset).start
7760    }
7761
7762    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7763    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7764        self.diff_transforms
7765            .seek(&OutputDimension(range.start), Bias::Right);
7766        let start = self.map_offset_to_buffer_internal(range.start);
7767        let end = if range.end > range.start {
7768            self.diff_transforms
7769                .seek_forward(&OutputDimension(range.end), Bias::Right);
7770            self.map_offset_to_buffer_internal(range.end)
7771        } else {
7772            start
7773        };
7774        start..end
7775    }
7776
7777    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7778        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7779        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7780            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7781        };
7782        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7783        self.buffer_offset + offset_in_excerpt
7784    }
7785
7786    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7787    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7788        self.map_range_from_buffer(buffer_offset..buffer_offset)
7789            .start
7790    }
7791
7792    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7793    pub fn map_range_from_buffer(
7794        &mut self,
7795        buffer_range: Range<BufferOffset>,
7796    ) -> Range<MultiBufferOffset> {
7797        if buffer_range.start < self.buffer_offset {
7798            log::warn!(
7799                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7800            );
7801            return self.offset..self.offset;
7802        }
7803        let overshoot = buffer_range.start - self.buffer_offset;
7804        let excerpt_offset = self.excerpt_offset + overshoot;
7805        let excerpt_seek_dim = excerpt_offset;
7806        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7807        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7808            log::warn!(
7809                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7810            );
7811            return self.offset..self.offset;
7812        }
7813        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7814        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7815
7816        let end = if buffer_range.start < buffer_range.end {
7817            let overshoot = buffer_range.end - self.buffer_offset;
7818            let excerpt_offset = self.excerpt_offset + overshoot;
7819            let excerpt_seek_dim = excerpt_offset;
7820            self.diff_transforms
7821                .seek_forward(&excerpt_seek_dim, Bias::Right);
7822            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7823            // todo(lw): Clamp end to the excerpt boundaries
7824            self.diff_transforms.start().output_dimension.0 + overshoot
7825        } else {
7826            start
7827        };
7828
7829        start..end
7830    }
7831
7832    /// Returns true if the entirety of the given range is in the buffer's excerpt
7833    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7834        range.start >= self.excerpt.buffer_start_offset()
7835            && range.end <= self.excerpt.buffer_end_offset()
7836    }
7837
7838    /// Returns true if any part of the given range is in the buffer's excerpt
7839    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7840        range.start <= self.excerpt.buffer_end_offset()
7841            && range.end >= self.excerpt.buffer_start_offset()
7842    }
7843
7844    pub fn max_buffer_row(&self) -> u32 {
7845        self.excerpt.max_buffer_row
7846    }
7847}
7848
7849impl ExcerptId {
7850    pub fn min() -> Self {
7851        Self(0)
7852    }
7853
7854    pub fn max() -> Self {
7855        Self(u32::MAX)
7856    }
7857
7858    pub fn to_proto(self) -> u64 {
7859        self.0 as _
7860    }
7861
7862    pub fn from_proto(proto: u64) -> Self {
7863        Self(proto as _)
7864    }
7865
7866    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7867        let a = snapshot.excerpt_locator_for_id(*self);
7868        let b = snapshot.excerpt_locator_for_id(*other);
7869        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7870    }
7871}
7872
7873impl From<ExcerptId> for usize {
7874    fn from(val: ExcerptId) -> Self {
7875        val.0 as usize
7876    }
7877}
7878
7879impl fmt::Debug for Excerpt {
7880    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7881        f.debug_struct("Excerpt")
7882            .field("id", &self.id)
7883            .field("locator", &self.locator)
7884            .field("buffer_id", &self.buffer_id)
7885            .field("range", &self.range)
7886            .field("text_summary", &self.text_summary)
7887            .field("has_trailing_newline", &self.has_trailing_newline)
7888            .finish()
7889    }
7890}
7891
7892impl sum_tree::Item for Excerpt {
7893    type Summary = ExcerptSummary;
7894
7895    fn summary(&self, _cx: ()) -> Self::Summary {
7896        let mut text = self.text_summary;
7897        if self.has_trailing_newline {
7898            text += TextSummary::from("\n");
7899        }
7900        ExcerptSummary {
7901            excerpt_id: self.id,
7902            excerpt_locator: self.locator.clone(),
7903            widest_line_number: self.max_buffer_row,
7904            text: text.into(),
7905            count: 1,
7906        }
7907    }
7908}
7909
7910impl sum_tree::Item for ExcerptIdMapping {
7911    type Summary = ExcerptId;
7912
7913    fn summary(&self, _cx: ()) -> Self::Summary {
7914        self.id
7915    }
7916}
7917
7918impl sum_tree::KeyedItem for ExcerptIdMapping {
7919    type Key = ExcerptId;
7920
7921    fn key(&self) -> Self::Key {
7922        self.id
7923    }
7924}
7925
7926impl DiffTransform {
7927    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7928        match self {
7929            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7930            DiffTransform::BufferContent {
7931                inserted_hunk_info, ..
7932            } => *inserted_hunk_info,
7933        }
7934    }
7935}
7936
7937impl sum_tree::Item for DiffTransform {
7938    type Summary = DiffTransformSummary;
7939
7940    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7941        match self {
7942            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7943                input: *summary,
7944                output: *summary,
7945            },
7946            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7947                input: MBTextSummary::default(),
7948                output: summary.into(),
7949            },
7950        }
7951    }
7952}
7953
7954impl DiffTransformSummary {
7955    fn excerpt_len(&self) -> ExcerptOffset {
7956        ExcerptDimension(self.input.len)
7957    }
7958}
7959
7960impl sum_tree::ContextLessSummary for DiffTransformSummary {
7961    fn zero() -> Self {
7962        DiffTransformSummary {
7963            input: MBTextSummary::default(),
7964            output: MBTextSummary::default(),
7965        }
7966    }
7967
7968    fn add_summary(&mut self, other: &Self) {
7969        self.input += other.input;
7970        self.output += other.output;
7971    }
7972}
7973
7974impl sum_tree::ContextLessSummary for ExcerptId {
7975    fn zero() -> Self {
7976        Self(0)
7977    }
7978
7979    fn add_summary(&mut self, summary: &Self) {
7980        *self = cmp::max(*self, *summary);
7981    }
7982}
7983
7984impl sum_tree::ContextLessSummary for ExcerptSummary {
7985    fn zero() -> Self {
7986        Self::default()
7987    }
7988
7989    fn add_summary(&mut self, summary: &Self) {
7990        debug_assert!(
7991            summary.excerpt_locator > self.excerpt_locator
7992                || self.excerpt_locator == Locator::min(),
7993            "Excerpt locators must be in ascending order: {:?} > {:?}",
7994            summary.excerpt_locator,
7995            self.excerpt_locator
7996        );
7997        self.excerpt_locator = summary.excerpt_locator.clone();
7998        self.text += summary.text;
7999        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
8000        self.count += summary.count;
8001    }
8002}
8003
8004impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8005    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8006        Ord::cmp(&Some(self), cursor_location)
8007    }
8008}
8009
8010impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8011    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8012        Ord::cmp(self, &cursor_location.excerpt_locator)
8013    }
8014}
8015
8016impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8017where
8018    MBD: MultiBufferDimension + Default,
8019{
8020    fn zero(_: ()) -> Self {
8021        ExcerptDimension(MBD::default())
8022    }
8023
8024    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8025        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8026    }
8027}
8028
8029impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8030    fn zero(_cx: ()) -> Self {
8031        Default::default()
8032    }
8033
8034    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8035        *self = Some(&summary.excerpt_locator);
8036    }
8037}
8038
8039impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8040    fn zero(_cx: ()) -> Self {
8041        Default::default()
8042    }
8043
8044    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8045        *self = Some(summary.excerpt_id);
8046    }
8047}
8048
8049#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8050struct OutputDimension<T>(T);
8051
8052impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8053    fn eq(&self, other: &T) -> bool {
8054        self.0 == *other
8055    }
8056}
8057
8058impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8059    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8060        self.0.partial_cmp(other)
8061    }
8062}
8063
8064impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8065where
8066    T: ops::Sub<U, Output = R>,
8067{
8068    type Output = R;
8069
8070    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8071        self.0 - other.0
8072    }
8073}
8074
8075impl<R, T, U> ops::Add<U> for OutputDimension<T>
8076where
8077    T: ops::Add<U, Output = R>,
8078{
8079    type Output = OutputDimension<R>;
8080
8081    fn add(self, other: U) -> Self::Output {
8082        OutputDimension(self.0 + other)
8083    }
8084}
8085
8086impl<T, U> AddAssign<U> for OutputDimension<T>
8087where
8088    T: AddAssign<U>,
8089{
8090    fn add_assign(&mut self, other: U) {
8091        self.0 += other;
8092    }
8093}
8094
8095impl<T, U> SubAssign<U> for OutputDimension<T>
8096where
8097    T: SubAssign<U>,
8098{
8099    fn sub_assign(&mut self, other: U) {
8100        self.0 -= other;
8101    }
8102}
8103
8104#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8105struct ExcerptDimension<T>(T);
8106
8107impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8108    fn eq(&self, other: &T) -> bool {
8109        self.0 == *other
8110    }
8111}
8112
8113impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8114    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8115        self.0.partial_cmp(other)
8116    }
8117}
8118
8119impl ExcerptOffset {
8120    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8121        self.0.saturating_sub(other.0)
8122    }
8123}
8124
8125impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8126where
8127    T: ops::Sub<U, Output = R>,
8128{
8129    type Output = R;
8130
8131    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8132        self.0 - other.0
8133    }
8134}
8135
8136impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8137where
8138    T: ops::Add<U, Output = R>,
8139{
8140    type Output = ExcerptDimension<R>;
8141
8142    fn add(self, other: U) -> Self::Output {
8143        ExcerptDimension(self.0 + other)
8144    }
8145}
8146
8147impl<T, U> AddAssign<U> for ExcerptDimension<T>
8148where
8149    T: AddAssign<U>,
8150{
8151    fn add_assign(&mut self, other: U) {
8152        self.0 += other;
8153    }
8154}
8155
8156impl<T, U> SubAssign<U> for ExcerptDimension<T>
8157where
8158    T: SubAssign<U>,
8159{
8160    fn sub_assign(&mut self, other: U) {
8161        self.0 -= other;
8162    }
8163}
8164
8165impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8166    fn zero(_: ()) -> Self {
8167        MultiBufferOffset::ZERO
8168    }
8169
8170    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8171        *self += summary.output.len;
8172    }
8173}
8174
8175impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8176    for ExcerptDimension<MBD>
8177where
8178    MBD: MultiBufferDimension + Ord,
8179{
8180    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8181        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8182    }
8183}
8184
8185impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8186    for ExcerptDimension<MBD>
8187where
8188    MBD: MultiBufferDimension + Ord,
8189{
8190    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8191        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8192    }
8193}
8194
8195impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8196    for ExcerptDimension<MBD>
8197{
8198    fn zero(_: ()) -> Self {
8199        ExcerptDimension(MBD::default())
8200    }
8201
8202    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8203        self.0.add_mb_text_summary(&summary.input)
8204    }
8205}
8206
8207impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8208    for OutputDimension<MBD>
8209where
8210    MBD: MultiBufferDimension + Ord,
8211{
8212    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8213        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8214    }
8215}
8216
8217impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8218    for OutputDimension<MBD>
8219{
8220    fn zero(_: ()) -> Self {
8221        OutputDimension(MBD::default())
8222    }
8223
8224    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8225        self.0.add_mb_text_summary(&summary.output)
8226    }
8227}
8228
8229impl MultiBufferRows<'_> {
8230    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8231        self.point = Point::new(row, 0);
8232        self.cursor.seek(&self.point);
8233    }
8234}
8235
8236impl Iterator for MultiBufferRows<'_> {
8237    type Item = RowInfo;
8238
8239    fn next(&mut self) -> Option<Self::Item> {
8240        if self.is_empty && self.point.row == 0 {
8241            self.point += Point::new(1, 0);
8242            return Some(RowInfo {
8243                buffer_id: None,
8244                buffer_row: Some(0),
8245                multibuffer_row: Some(MultiBufferRow(0)),
8246                diff_status: None,
8247                expand_info: None,
8248                wrapped_buffer_row: None,
8249            });
8250        }
8251
8252        let mut region = self.cursor.region()?.clone();
8253        while self.point >= region.range.end {
8254            self.cursor.next();
8255            if let Some(next_region) = self.cursor.region() {
8256                region = next_region.clone();
8257            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8258                let multibuffer_row = MultiBufferRow(self.point.row);
8259                let last_excerpt = self
8260                    .cursor
8261                    .excerpts
8262                    .item()
8263                    .or(self.cursor.excerpts.prev_item())?;
8264                let last_row = last_excerpt
8265                    .range
8266                    .context
8267                    .end
8268                    .to_point(&last_excerpt.buffer)
8269                    .row;
8270
8271                let first_row = last_excerpt
8272                    .range
8273                    .context
8274                    .start
8275                    .to_point(&last_excerpt.buffer)
8276                    .row;
8277
8278                let expand_info = if self.is_singleton {
8279                    None
8280                } else {
8281                    let needs_expand_up = first_row == last_row
8282                        && last_row > 0
8283                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8284                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8285
8286                    if needs_expand_up && needs_expand_down {
8287                        Some(ExpandExcerptDirection::UpAndDown)
8288                    } else if needs_expand_up {
8289                        Some(ExpandExcerptDirection::Up)
8290                    } else if needs_expand_down {
8291                        Some(ExpandExcerptDirection::Down)
8292                    } else {
8293                        None
8294                    }
8295                    .map(|direction| ExpandInfo {
8296                        direction,
8297                        excerpt_id: last_excerpt.id,
8298                    })
8299                };
8300                self.point += Point::new(1, 0);
8301                return Some(RowInfo {
8302                    buffer_id: Some(last_excerpt.buffer_id),
8303                    buffer_row: Some(last_row),
8304                    multibuffer_row: Some(multibuffer_row),
8305                    diff_status: None,
8306                    wrapped_buffer_row: None,
8307                    expand_info,
8308                });
8309            } else {
8310                return None;
8311            };
8312        }
8313
8314        let overshoot = self.point - region.range.start;
8315        let buffer_point = region.buffer_range.start + overshoot;
8316        let expand_info = if self.is_singleton {
8317            None
8318        } else {
8319            let needs_expand_up = self.point.row == region.range.start.row
8320                && self.cursor.is_at_start_of_excerpt()
8321                && buffer_point.row > 0;
8322            let needs_expand_down = (region.excerpt.has_trailing_newline
8323                && self.point.row + 1 == region.range.end.row
8324                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8325                && self.cursor.is_at_end_of_excerpt()
8326                && buffer_point.row < region.buffer.max_point().row;
8327
8328            if needs_expand_up && needs_expand_down {
8329                Some(ExpandExcerptDirection::UpAndDown)
8330            } else if needs_expand_up {
8331                Some(ExpandExcerptDirection::Up)
8332            } else if needs_expand_down {
8333                Some(ExpandExcerptDirection::Down)
8334            } else {
8335                None
8336            }
8337            .map(|direction| ExpandInfo {
8338                direction,
8339                excerpt_id: region.excerpt.id,
8340            })
8341        };
8342
8343        let result = Some(RowInfo {
8344            buffer_id: Some(region.buffer.remote_id()),
8345            buffer_row: Some(buffer_point.row),
8346            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8347            diff_status: region
8348                .diff_hunk_status
8349                .filter(|_| self.point < region.range.end),
8350            expand_info,
8351            wrapped_buffer_row: None,
8352        });
8353        self.point += Point::new(1, 0);
8354        result
8355    }
8356}
8357
8358impl<'a> MultiBufferChunks<'a> {
8359    pub fn offset(&self) -> MultiBufferOffset {
8360        self.range.start
8361    }
8362
8363    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8364        self.diff_transforms.seek(&range.end, Bias::Right);
8365        let mut excerpt_end = self.diff_transforms.start().1;
8366        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8367            let overshoot = range.end - self.diff_transforms.start().0;
8368            excerpt_end += overshoot;
8369        }
8370
8371        self.diff_transforms.seek(&range.start, Bias::Right);
8372        let mut excerpt_start = self.diff_transforms.start().1;
8373        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8374            let overshoot = range.start - self.diff_transforms.start().0;
8375            excerpt_start += overshoot;
8376        }
8377
8378        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8379        self.buffer_chunk.take();
8380        self.range = range;
8381    }
8382
8383    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8384        self.excerpt_offset_range = new_range.clone();
8385        self.excerpts.seek(&new_range.start, Bias::Right);
8386        if let Some(excerpt) = self.excerpts.item() {
8387            let excerpt_start = *self.excerpts.start();
8388            if let Some(excerpt_chunks) = self
8389                .excerpt_chunks
8390                .as_mut()
8391                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8392            {
8393                excerpt.seek_chunks(
8394                    excerpt_chunks,
8395                    (self.excerpt_offset_range.start - excerpt_start)
8396                        ..(self.excerpt_offset_range.end - excerpt_start),
8397                );
8398            } else {
8399                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8400                    (self.excerpt_offset_range.start - excerpt_start)
8401                        ..(self.excerpt_offset_range.end - excerpt_start),
8402                    self.language_aware,
8403                ));
8404            }
8405        } else {
8406            self.excerpt_chunks = None;
8407        }
8408    }
8409
8410    #[ztracing::instrument(skip_all)]
8411    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8412        loop {
8413            if self.excerpt_offset_range.is_empty() {
8414                return None;
8415            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8416                self.excerpt_offset_range.start += chunk.text.len();
8417                return Some(chunk);
8418            } else {
8419                self.excerpts.next();
8420                let excerpt = self.excerpts.item()?;
8421                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8422                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8423                    self.language_aware,
8424                ));
8425            }
8426        }
8427    }
8428}
8429
8430impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8431    type Item = &'a str;
8432
8433    fn next(&mut self) -> Option<Self::Item> {
8434        let mut region = self.cursor.region()?;
8435        if self.offset == region.range.start {
8436            self.cursor.prev();
8437            region = self.cursor.region()?;
8438            let start_overshoot = self.start.saturating_sub(region.range.start);
8439            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8440                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8441            ));
8442        }
8443
8444        if self.offset == region.range.end && region.has_trailing_newline {
8445            self.offset -= 1;
8446            Some("\n")
8447        } else {
8448            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8449            self.offset -= chunk.len();
8450            Some(chunk)
8451        }
8452    }
8453}
8454
8455impl<'a> Iterator for MultiBufferChunks<'a> {
8456    type Item = Chunk<'a>;
8457
8458    #[ztracing::instrument(skip_all)]
8459    fn next(&mut self) -> Option<Chunk<'a>> {
8460        if self.range.start >= self.range.end {
8461            return None;
8462        }
8463        if self.range.start == self.diff_transforms.end().0 {
8464            self.diff_transforms.next();
8465        }
8466
8467        let diff_transform_start = self.diff_transforms.start().0;
8468        let diff_transform_end = self.diff_transforms.end().0;
8469        debug_assert!(
8470            self.range.start < diff_transform_end,
8471            "{:?} < {:?} of ({1:?}..{2:?})",
8472            self.range.start,
8473            diff_transform_end,
8474            diff_transform_start
8475        );
8476
8477        let diff_transform = self.diff_transforms.item()?;
8478        match diff_transform {
8479            DiffTransform::BufferContent { .. } => {
8480                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8481                    chunk
8482                } else {
8483                    let chunk = self.next_excerpt_chunk().unwrap();
8484                    self.buffer_chunk.insert(chunk)
8485                };
8486
8487                let chunk_end = self.range.start + chunk.text.len();
8488                let diff_transform_end = diff_transform_end.min(self.range.end);
8489
8490                if diff_transform_end < chunk_end {
8491                    let split_idx = diff_transform_end - self.range.start;
8492                    let (before, after) = chunk.text.split_at(split_idx);
8493                    self.range.start = diff_transform_end;
8494                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8495                    let chars = chunk.chars & mask;
8496                    let tabs = chunk.tabs & mask;
8497                    let newlines = chunk.newlines & mask;
8498
8499                    chunk.text = after;
8500                    chunk.chars = chunk.chars >> split_idx;
8501                    chunk.tabs = chunk.tabs >> split_idx;
8502                    chunk.newlines = chunk.newlines >> split_idx;
8503
8504                    Some(Chunk {
8505                        text: before,
8506                        chars,
8507                        tabs,
8508                        newlines,
8509                        ..chunk.clone()
8510                    })
8511                } else {
8512                    self.range.start = chunk_end;
8513                    self.buffer_chunk.take()
8514                }
8515            }
8516            DiffTransform::DeletedHunk {
8517                buffer_id,
8518                base_text_byte_range,
8519                has_trailing_newline,
8520                ..
8521            } => {
8522                let base_text_start =
8523                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8524                let base_text_end =
8525                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8526                let base_text_end = base_text_end.min(base_text_byte_range.end);
8527
8528                let mut chunks = if let Some((_, mut chunks)) = self
8529                    .diff_base_chunks
8530                    .take()
8531                    .filter(|(id, _)| id == buffer_id)
8532                {
8533                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8534                    {
8535                        chunks.seek(base_text_start..base_text_end);
8536                    }
8537                    chunks
8538                } else {
8539                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8540                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8541                };
8542
8543                let chunk = if let Some(chunk) = chunks.next() {
8544                    self.range.start += chunk.text.len();
8545                    self.diff_base_chunks = Some((*buffer_id, chunks));
8546                    chunk
8547                } else {
8548                    debug_assert!(has_trailing_newline);
8549                    self.range.start += "\n".len();
8550                    Chunk {
8551                        text: "\n",
8552                        chars: 1u128,
8553                        newlines: 1u128,
8554                        ..Default::default()
8555                    }
8556                };
8557                Some(chunk)
8558            }
8559        }
8560    }
8561}
8562
8563impl MultiBufferBytes<'_> {
8564    fn consume(&mut self, len: usize) {
8565        self.range.start += len;
8566        self.chunk = &self.chunk[len..];
8567
8568        if !self.range.is_empty() && self.chunk.is_empty() {
8569            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8570                self.chunk = chunk;
8571            } else if self.has_trailing_newline {
8572                self.has_trailing_newline = false;
8573                self.chunk = b"\n";
8574            } else {
8575                self.cursor.next();
8576                if let Some(region) = self.cursor.region() {
8577                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8578                        region.buffer_range.start
8579                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8580                                .min(region.buffer_range.end),
8581                    );
8582                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8583                    self.excerpt_bytes = Some(excerpt_bytes);
8584                    self.has_trailing_newline =
8585                        region.has_trailing_newline && self.range.end >= region.range.end;
8586                    if self.chunk.is_empty() && self.has_trailing_newline {
8587                        self.has_trailing_newline = false;
8588                        self.chunk = b"\n";
8589                    }
8590                }
8591            }
8592        }
8593    }
8594}
8595
8596impl<'a> Iterator for MultiBufferBytes<'a> {
8597    type Item = &'a [u8];
8598
8599    fn next(&mut self) -> Option<Self::Item> {
8600        let chunk = self.chunk;
8601        if chunk.is_empty() {
8602            None
8603        } else {
8604            self.consume(chunk.len());
8605            Some(chunk)
8606        }
8607    }
8608}
8609
8610impl io::Read for MultiBufferBytes<'_> {
8611    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8612        let len = cmp::min(buf.len(), self.chunk.len());
8613        buf[..len].copy_from_slice(&self.chunk[..len]);
8614        if len > 0 {
8615            self.consume(len);
8616        }
8617        Ok(len)
8618    }
8619}
8620
8621impl io::Read for ReversedMultiBufferBytes<'_> {
8622    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8623        let len = cmp::min(buf.len(), self.chunk.len());
8624        buf[..len].copy_from_slice(&self.chunk[..len]);
8625        buf[..len].reverse();
8626        if len > 0 {
8627            self.range.end -= len;
8628            self.chunk = &self.chunk[..self.chunk.len() - len];
8629            if !self.range.is_empty()
8630                && self.chunk.is_empty()
8631                && let Some(chunk) = self.chunks.next()
8632            {
8633                self.chunk = chunk.as_bytes();
8634            }
8635        }
8636        Ok(len)
8637    }
8638}
8639
8640impl<'a> Iterator for ExcerptChunks<'a> {
8641    type Item = Chunk<'a>;
8642
8643    fn next(&mut self) -> Option<Self::Item> {
8644        if let Some(chunk) = self.content_chunks.next() {
8645            return Some(chunk);
8646        }
8647
8648        if self.has_footer {
8649            let text = "\n";
8650            let chars = 0b1;
8651            let newlines = 0b1;
8652            self.has_footer = false;
8653            return Some(Chunk {
8654                text,
8655                chars,
8656                newlines,
8657                ..Default::default()
8658            });
8659        }
8660
8661        None
8662    }
8663}
8664
8665impl ToOffset for Point {
8666    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8667        snapshot.point_to_offset(*self)
8668    }
8669    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8670        snapshot.point_to_offset_utf16(*self)
8671    }
8672}
8673
8674impl ToOffset for MultiBufferOffset {
8675    #[track_caller]
8676    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8677        assert!(
8678            *self <= snapshot.len(),
8679            "offset {} is greater than the snapshot.len() {}",
8680            self.0,
8681            snapshot.len().0,
8682        );
8683        *self
8684    }
8685    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8686        snapshot.offset_to_offset_utf16(*self)
8687    }
8688}
8689
8690impl ToOffset for MultiBufferOffsetUtf16 {
8691    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8692        snapshot.offset_utf16_to_offset(*self)
8693    }
8694
8695    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8696        *self
8697    }
8698}
8699
8700impl ToOffset for PointUtf16 {
8701    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8702        snapshot.point_utf16_to_offset(*self)
8703    }
8704    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8705        snapshot.point_utf16_to_offset_utf16(*self)
8706    }
8707}
8708
8709impl ToPoint for MultiBufferOffset {
8710    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8711        snapshot.offset_to_point(*self)
8712    }
8713    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8714        snapshot.offset_to_point_utf16(*self)
8715    }
8716}
8717
8718impl ToPoint for Point {
8719    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8720        *self
8721    }
8722    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8723        snapshot.point_to_point_utf16(*self)
8724    }
8725}
8726
8727impl ToPoint for PointUtf16 {
8728    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8729        snapshot.point_utf16_to_point(*self)
8730    }
8731    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8732        *self
8733    }
8734}
8735
8736impl From<ExcerptId> for EntityId {
8737    fn from(id: ExcerptId) -> Self {
8738        EntityId::from(id.0 as u64)
8739    }
8740}
8741
8742#[cfg(debug_assertions)]
8743pub mod debug {
8744    use super::*;
8745
8746    pub trait ToMultiBufferDebugRanges {
8747        fn to_multi_buffer_debug_ranges(
8748            &self,
8749            snapshot: &MultiBufferSnapshot,
8750        ) -> Vec<Range<MultiBufferOffset>>;
8751    }
8752
8753    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8754        fn to_multi_buffer_debug_ranges(
8755            &self,
8756            snapshot: &MultiBufferSnapshot,
8757        ) -> Vec<Range<MultiBufferOffset>> {
8758            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8759        }
8760    }
8761
8762    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8763        fn to_multi_buffer_debug_ranges(
8764            &self,
8765            snapshot: &MultiBufferSnapshot,
8766        ) -> Vec<Range<MultiBufferOffset>> {
8767            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8768                .to_multi_buffer_debug_ranges(snapshot)
8769        }
8770    }
8771
8772    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8773        fn to_multi_buffer_debug_ranges(
8774            &self,
8775            snapshot: &MultiBufferSnapshot,
8776        ) -> Vec<Range<MultiBufferOffset>> {
8777            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8778        }
8779    }
8780
8781    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8782        fn to_multi_buffer_debug_ranges(
8783            &self,
8784            snapshot: &MultiBufferSnapshot,
8785        ) -> Vec<Range<MultiBufferOffset>> {
8786            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8787        }
8788    }
8789
8790    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8791        fn to_multi_buffer_debug_ranges(
8792            &self,
8793            snapshot: &MultiBufferSnapshot,
8794        ) -> Vec<Range<MultiBufferOffset>> {
8795            self.iter()
8796                .map(|item| {
8797                    let offset = item.to_offset(snapshot);
8798                    offset..offset
8799                })
8800                .collect()
8801        }
8802    }
8803
8804    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8805        fn to_multi_buffer_debug_ranges(
8806            &self,
8807            snapshot: &MultiBufferSnapshot,
8808        ) -> Vec<Range<MultiBufferOffset>> {
8809            self.iter()
8810                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8811                .collect()
8812        }
8813    }
8814}