multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    main_buffer: Option<Entity<language::Buffer>>,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    main_buffer: Option<language::BufferSnapshot>,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            main_buffer: None,
 577        }
 578    }
 579
 580    fn new_inverted(
 581        diff: Entity<BufferDiff>,
 582        main_buffer: Entity<language::Buffer>,
 583        cx: &mut Context<MultiBuffer>,
 584    ) -> Self {
 585        let weak_main_buffer = main_buffer.downgrade();
 586        DiffState {
 587            _subscription: cx.subscribe(&diff, {
 588                move |this, diff, event, cx| {
 589                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 590                        return;
 591                    };
 592                    match event {
 593                        BufferDiffEvent::DiffChanged(DiffChanged {
 594                            changed_range: _,
 595                            base_text_changed_range,
 596                            extended_range: _,
 597                        }) => {
 598                            if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 599                                this.inverted_buffer_diff_changed(
 600                                    diff,
 601                                    main_buffer,
 602                                    base_text_changed_range,
 603                                    cx,
 604                                )
 605                            }
 606                            cx.emit(Event::BufferDiffChanged);
 607                        }
 608                        BufferDiffEvent::LanguageChanged => {
 609                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 610                        }
 611                        _ => {}
 612                    }
 613                }
 614            }),
 615            diff,
 616            main_buffer: Some(main_buffer),
 617        }
 618    }
 619}
 620
 621/// The contents of a [`MultiBuffer`] at a single point in time.
 622#[derive(Clone, Default)]
 623pub struct MultiBufferSnapshot {
 624    excerpts: SumTree<Excerpt>,
 625    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 626    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 627    diff_transforms: SumTree<DiffTransform>,
 628    excerpt_ids: SumTree<ExcerptIdMapping>,
 629    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 630    non_text_state_update_count: usize,
 631    edit_count: usize,
 632    is_dirty: bool,
 633    has_deleted_file: bool,
 634    has_conflict: bool,
 635    has_inverted_diff: bool,
 636    singleton: bool,
 637    trailing_excerpt_update_count: usize,
 638    all_diff_hunks_expanded: bool,
 639    show_deleted_hunks: bool,
 640    use_extended_diff_range: bool,
 641    show_headers: bool,
 642}
 643
 644// follower: None
 645// - BufferContent(Some)
 646// - BufferContent(None)
 647// - DeletedHunk
 648//
 649// follower: Some
 650// - BufferContent(Some)
 651// - BufferContent(None)
 652
 653#[derive(Debug, Clone)]
 654enum DiffTransform {
 655    // RealText
 656    BufferContent {
 657        summary: MBTextSummary,
 658        // modified_hunk_info
 659        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 660    },
 661    // ExpandedHunkText
 662    DeletedHunk {
 663        summary: TextSummary,
 664        buffer_id: BufferId,
 665        hunk_info: DiffTransformHunkInfo,
 666        base_text_byte_range: Range<usize>,
 667        has_trailing_newline: bool,
 668    },
 669}
 670
 671#[derive(Clone, Copy, Debug)]
 672struct DiffTransformHunkInfo {
 673    excerpt_id: ExcerptId,
 674    hunk_start_anchor: text::Anchor,
 675    hunk_secondary_status: DiffHunkSecondaryStatus,
 676    is_logically_deleted: bool,
 677}
 678
 679impl Eq for DiffTransformHunkInfo {}
 680
 681impl PartialEq for DiffTransformHunkInfo {
 682    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 683        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 684    }
 685}
 686
 687impl std::hash::Hash for DiffTransformHunkInfo {
 688    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 689        self.excerpt_id.hash(state);
 690        self.hunk_start_anchor.hash(state);
 691    }
 692}
 693
 694#[derive(Clone)]
 695pub struct ExcerptInfo {
 696    pub id: ExcerptId,
 697    pub buffer: Arc<BufferSnapshot>,
 698    pub buffer_id: BufferId,
 699    pub range: ExcerptRange<text::Anchor>,
 700    pub end_row: MultiBufferRow,
 701}
 702
 703impl std::fmt::Debug for ExcerptInfo {
 704    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 705        f.debug_struct(type_name::<Self>())
 706            .field("id", &self.id)
 707            .field("buffer_id", &self.buffer_id)
 708            .field("path", &self.buffer.file().map(|f| f.path()))
 709            .field("range", &self.range)
 710            .finish()
 711    }
 712}
 713
 714/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 715#[derive(Debug)]
 716pub struct ExcerptBoundary {
 717    pub prev: Option<ExcerptInfo>,
 718    pub next: ExcerptInfo,
 719    /// The row in the `MultiBuffer` where the boundary is located
 720    pub row: MultiBufferRow,
 721}
 722
 723impl ExcerptBoundary {
 724    pub fn starts_new_buffer(&self) -> bool {
 725        match (self.prev.as_ref(), &self.next) {
 726            (None, _) => true,
 727            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 728        }
 729    }
 730}
 731
 732#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 733pub struct ExpandInfo {
 734    pub direction: ExpandExcerptDirection,
 735    pub excerpt_id: ExcerptId,
 736}
 737
 738#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 739pub struct RowInfo {
 740    pub buffer_id: Option<BufferId>,
 741    pub buffer_row: Option<u32>,
 742    pub multibuffer_row: Option<MultiBufferRow>,
 743    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 744    pub expand_info: Option<ExpandInfo>,
 745    pub wrapped_buffer_row: Option<u32>,
 746}
 747
 748/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 749#[derive(Clone)]
 750struct Excerpt {
 751    /// The unique identifier for this excerpt
 752    id: ExcerptId,
 753    /// The location of the excerpt in the [`MultiBuffer`]
 754    locator: Locator,
 755    /// The buffer being excerpted
 756    buffer_id: BufferId,
 757    /// A snapshot of the buffer being excerpted
 758    buffer: Arc<BufferSnapshot>,
 759    /// The range of the buffer to be shown in the excerpt
 760    range: ExcerptRange<text::Anchor>,
 761    /// The last row in the excerpted slice of the buffer
 762    max_buffer_row: BufferRow,
 763    /// A summary of the text in the excerpt
 764    text_summary: TextSummary,
 765    has_trailing_newline: bool,
 766}
 767
 768/// A public view into an `Excerpt` in a [`MultiBuffer`].
 769///
 770/// Contains methods for getting the [`Buffer`] of the excerpt,
 771/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 772#[derive(Clone)]
 773pub struct MultiBufferExcerpt<'a> {
 774    excerpt: &'a Excerpt,
 775    diff_transforms:
 776        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 777    /// The offset in the multibuffer considering diff transforms.
 778    offset: MultiBufferOffset,
 779    /// The offset in the multibuffer without diff transforms.
 780    excerpt_offset: ExcerptOffset,
 781    buffer_offset: BufferOffset,
 782}
 783
 784#[derive(Clone, Debug)]
 785struct ExcerptIdMapping {
 786    id: ExcerptId,
 787    locator: Locator,
 788}
 789
 790/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 791/// These ranges are relative to the buffer itself
 792#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 793pub struct ExcerptRange<T> {
 794    /// The full range of text to be shown in the excerpt.
 795    pub context: Range<T>,
 796    /// The primary range of text to be highlighted in the excerpt.
 797    /// In a multi-buffer search, this would be the text that matched the search
 798    pub primary: Range<T>,
 799}
 800
 801impl<T: Clone> ExcerptRange<T> {
 802    pub fn new(context: Range<T>) -> Self {
 803        Self {
 804            context: context.clone(),
 805            primary: context,
 806        }
 807    }
 808}
 809
 810#[derive(Clone, Debug, Default)]
 811pub struct ExcerptSummary {
 812    excerpt_id: ExcerptId,
 813    /// The location of the last [`Excerpt`] being summarized
 814    excerpt_locator: Locator,
 815    widest_line_number: u32,
 816    text: MBTextSummary,
 817    count: usize,
 818}
 819
 820#[derive(Debug, Clone)]
 821pub struct DiffTransformSummary {
 822    input: MBTextSummary,
 823    output: MBTextSummary,
 824}
 825
 826/// Summary of a string of text.
 827#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 828pub struct MBTextSummary {
 829    /// Length in bytes.
 830    pub len: MultiBufferOffset,
 831    /// Length in UTF-8.
 832    pub chars: usize,
 833    /// Length in UTF-16 code units
 834    pub len_utf16: OffsetUtf16,
 835    /// A point representing the number of lines and the length of the last line.
 836    ///
 837    /// In other words, it marks the point after the last byte in the text, (if
 838    /// EOF was a character, this would be its position).
 839    pub lines: Point,
 840    /// How many `char`s are in the first line
 841    pub first_line_chars: u32,
 842    /// How many `char`s are in the last line
 843    pub last_line_chars: u32,
 844    /// How many UTF-16 code units are in the last line
 845    pub last_line_len_utf16: u32,
 846    /// The row idx of the longest row
 847    pub longest_row: u32,
 848    /// How many `char`s are in the longest row
 849    pub longest_row_chars: u32,
 850}
 851
 852impl From<TextSummary> for MBTextSummary {
 853    fn from(summary: TextSummary) -> Self {
 854        MBTextSummary {
 855            len: MultiBufferOffset(summary.len),
 856            chars: summary.chars,
 857            len_utf16: summary.len_utf16,
 858            lines: summary.lines,
 859            first_line_chars: summary.first_line_chars,
 860            last_line_chars: summary.last_line_chars,
 861            last_line_len_utf16: summary.last_line_len_utf16,
 862            longest_row: summary.longest_row,
 863            longest_row_chars: summary.longest_row_chars,
 864        }
 865    }
 866}
 867
 868impl From<MBTextSummary> for TextSummary {
 869    fn from(summary: MBTextSummary) -> Self {
 870        TextSummary {
 871            len: summary.len.0,
 872            chars: summary.chars,
 873            len_utf16: summary.len_utf16,
 874            lines: summary.lines,
 875            first_line_chars: summary.first_line_chars,
 876            last_line_chars: summary.last_line_chars,
 877            last_line_len_utf16: summary.last_line_len_utf16,
 878            longest_row: summary.longest_row,
 879            longest_row_chars: summary.longest_row_chars,
 880        }
 881    }
 882}
 883
 884impl From<&str> for MBTextSummary {
 885    fn from(text: &str) -> Self {
 886        MBTextSummary::from(TextSummary::from(text))
 887    }
 888}
 889
 890impl MultiBufferDimension for MBTextSummary {
 891    type TextDimension = TextSummary;
 892
 893    fn from_summary(summary: &MBTextSummary) -> Self {
 894        *summary
 895    }
 896
 897    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 898        *self += *summary;
 899    }
 900
 901    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 902        *self += *summary;
 903    }
 904}
 905
 906impl AddAssign for MBTextSummary {
 907    fn add_assign(&mut self, other: MBTextSummary) {
 908        let joined_chars = self.last_line_chars + other.first_line_chars;
 909        if joined_chars > self.longest_row_chars {
 910            self.longest_row = self.lines.row;
 911            self.longest_row_chars = joined_chars;
 912        }
 913        if other.longest_row_chars > self.longest_row_chars {
 914            self.longest_row = self.lines.row + other.longest_row;
 915            self.longest_row_chars = other.longest_row_chars;
 916        }
 917
 918        if self.lines.row == 0 {
 919            self.first_line_chars += other.first_line_chars;
 920        }
 921
 922        if other.lines.row == 0 {
 923            self.last_line_chars += other.first_line_chars;
 924            self.last_line_len_utf16 += other.last_line_len_utf16;
 925        } else {
 926            self.last_line_chars = other.last_line_chars;
 927            self.last_line_len_utf16 = other.last_line_len_utf16;
 928        }
 929
 930        self.chars += other.chars;
 931        self.len += other.len;
 932        self.len_utf16 += other.len_utf16;
 933        self.lines += other.lines;
 934    }
 935}
 936
 937impl AddAssign<TextSummary> for MBTextSummary {
 938    fn add_assign(&mut self, other: TextSummary) {
 939        *self += MBTextSummary::from(other);
 940    }
 941}
 942
 943impl MBTextSummary {
 944    pub fn lines_utf16(&self) -> PointUtf16 {
 945        PointUtf16 {
 946            row: self.lines.row,
 947            column: self.last_line_len_utf16,
 948        }
 949    }
 950}
 951
 952impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 953where
 954    K: MultiBufferDimension,
 955    V: MultiBufferDimension,
 956{
 957    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 958
 959    fn from_summary(summary: &MBTextSummary) -> Self {
 960        Self {
 961            key: K::from_summary(summary),
 962            value: Some(V::from_summary(summary)),
 963        }
 964    }
 965
 966    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 967        self.key.add_text_dim(&summary.key);
 968        if let Some(value) = &mut self.value {
 969            if let Some(other_value) = summary.value.as_ref() {
 970                value.add_text_dim(other_value);
 971            }
 972        }
 973    }
 974
 975    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 976        self.key.add_mb_text_summary(summary);
 977        if let Some(value) = &mut self.value {
 978            value.add_mb_text_summary(summary);
 979        }
 980    }
 981}
 982
 983#[derive(Clone)]
 984pub struct MultiBufferRows<'a> {
 985    point: Point,
 986    is_empty: bool,
 987    is_singleton: bool,
 988    cursor: MultiBufferCursor<'a, Point, Point>,
 989}
 990
 991pub struct MultiBufferChunks<'a> {
 992    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 993    diff_transforms:
 994        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 995    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 996    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 997    buffer_chunk: Option<Chunk<'a>>,
 998    range: Range<MultiBufferOffset>,
 999    excerpt_offset_range: Range<ExcerptOffset>,
1000    excerpt_chunks: Option<ExcerptChunks<'a>>,
1001    language_aware: bool,
1002}
1003
1004pub struct ReversedMultiBufferChunks<'a> {
1005    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1006    current_chunks: Option<rope::Chunks<'a>>,
1007    start: MultiBufferOffset,
1008    offset: MultiBufferOffset,
1009}
1010
1011pub struct MultiBufferBytes<'a> {
1012    range: Range<MultiBufferOffset>,
1013    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1014    excerpt_bytes: Option<text::Bytes<'a>>,
1015    has_trailing_newline: bool,
1016    chunk: &'a [u8],
1017}
1018
1019pub struct ReversedMultiBufferBytes<'a> {
1020    range: Range<MultiBufferOffset>,
1021    chunks: ReversedMultiBufferChunks<'a>,
1022    chunk: &'a [u8],
1023}
1024
1025#[derive(Clone)]
1026struct DiffTransforms<MBD> {
1027    output_dimension: OutputDimension<MBD>,
1028    excerpt_dimension: ExcerptDimension<MBD>,
1029}
1030
1031impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1032    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1033        Self {
1034            output_dimension: OutputDimension::zero(cx),
1035            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1036                cx,
1037            ),
1038        }
1039    }
1040
1041    fn add_summary(
1042        &mut self,
1043        summary: &'a DiffTransformSummary,
1044        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1045    ) {
1046        self.output_dimension.add_summary(summary, cx);
1047        self.excerpt_dimension.add_summary(summary, cx);
1048    }
1049}
1050
1051#[derive(Clone)]
1052struct MultiBufferCursor<'a, MBD, BD> {
1053    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1054    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1055    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1056    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1057}
1058
1059#[derive(Clone)]
1060struct MultiBufferRegion<'a, MBD, BD> {
1061    buffer: &'a BufferSnapshot,
1062    is_main_buffer: bool,
1063    diff_hunk_status: Option<DiffHunkStatus>,
1064    excerpt: &'a Excerpt,
1065    buffer_range: Range<BD>,
1066    range: Range<MBD>,
1067    has_trailing_newline: bool,
1068}
1069
1070struct ExcerptChunks<'a> {
1071    excerpt_id: ExcerptId,
1072    content_chunks: BufferChunks<'a>,
1073    has_footer: bool,
1074}
1075
1076#[derive(Debug)]
1077struct BufferEdit {
1078    range: Range<BufferOffset>,
1079    new_text: Arc<str>,
1080    is_insertion: bool,
1081    original_indent_column: Option<u32>,
1082    excerpt_id: ExcerptId,
1083}
1084
1085#[derive(Clone, Copy, Debug, PartialEq)]
1086enum DiffChangeKind {
1087    BufferEdited,
1088    DiffUpdated { base_changed: bool },
1089    ExpandOrCollapseHunks { expand: bool },
1090}
1091
1092#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1093pub enum ExpandExcerptDirection {
1094    Up,
1095    Down,
1096    UpAndDown,
1097}
1098
1099impl ExpandExcerptDirection {
1100    pub fn should_expand_up(&self) -> bool {
1101        match self {
1102            ExpandExcerptDirection::Up => true,
1103            ExpandExcerptDirection::Down => false,
1104            ExpandExcerptDirection::UpAndDown => true,
1105        }
1106    }
1107
1108    pub fn should_expand_down(&self) -> bool {
1109        match self {
1110            ExpandExcerptDirection::Up => false,
1111            ExpandExcerptDirection::Down => true,
1112            ExpandExcerptDirection::UpAndDown => true,
1113        }
1114    }
1115}
1116
1117#[derive(Clone, Debug, PartialEq)]
1118pub struct IndentGuide {
1119    pub buffer_id: BufferId,
1120    pub start_row: MultiBufferRow,
1121    pub end_row: MultiBufferRow,
1122    pub depth: u32,
1123    pub tab_size: u32,
1124    pub settings: IndentGuideSettings,
1125}
1126
1127impl IndentGuide {
1128    pub fn indent_level(&self) -> u32 {
1129        self.depth * self.tab_size
1130    }
1131}
1132
1133impl MultiBuffer {
1134    pub fn new(capability: Capability) -> Self {
1135        Self::new_(
1136            capability,
1137            MultiBufferSnapshot {
1138                show_headers: true,
1139                show_deleted_hunks: true,
1140                ..MultiBufferSnapshot::default()
1141            },
1142        )
1143    }
1144
1145    pub fn without_headers(capability: Capability) -> Self {
1146        Self::new_(
1147            capability,
1148            MultiBufferSnapshot {
1149                show_deleted_hunks: true,
1150                ..MultiBufferSnapshot::default()
1151            },
1152        )
1153    }
1154
1155    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1156        let mut this = Self::new_(
1157            buffer.read(cx).capability(),
1158            MultiBufferSnapshot {
1159                singleton: true,
1160                show_deleted_hunks: true,
1161                ..MultiBufferSnapshot::default()
1162            },
1163        );
1164        this.singleton = true;
1165        let buffer_id = buffer.read(cx).remote_id();
1166        this.push_excerpts(
1167            buffer,
1168            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1169                buffer_id,
1170            ))],
1171            cx,
1172        );
1173        this
1174    }
1175
1176    #[inline]
1177    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1178        Self {
1179            snapshot: RefCell::new(snapshot),
1180            buffers: Default::default(),
1181            diffs: HashMap::default(),
1182            subscriptions: Topic::default(),
1183            singleton: false,
1184            capability,
1185            title: None,
1186            excerpts_by_path: Default::default(),
1187            paths_by_excerpt: Default::default(),
1188            buffer_changed_since_sync: Default::default(),
1189            history: History::default(),
1190        }
1191    }
1192
1193    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1194        let mut buffers = BTreeMap::default();
1195        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1196        for (buffer_id, buffer_state) in self.buffers.iter() {
1197            buffer_state.buffer.update(new_cx, |buffer, _| {
1198                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1199            });
1200            buffers.insert(
1201                *buffer_id,
1202                BufferState {
1203                    buffer: buffer_state.buffer.clone(),
1204                    last_version: buffer_state.last_version.clone(),
1205                    last_non_text_state_update_count: buffer_state
1206                        .last_non_text_state_update_count
1207                        .clone(),
1208                    excerpts: buffer_state.excerpts.clone(),
1209                    _subscriptions: [
1210                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1211                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1212                    ],
1213                },
1214            );
1215        }
1216        let mut diff_bases = HashMap::default();
1217        for (buffer_id, diff) in self.diffs.iter() {
1218            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1219        }
1220        Self {
1221            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1222            buffers,
1223            excerpts_by_path: Default::default(),
1224            paths_by_excerpt: Default::default(),
1225            diffs: diff_bases,
1226            subscriptions: Default::default(),
1227            singleton: self.singleton,
1228            capability: self.capability,
1229            history: self.history.clone(),
1230            title: self.title.clone(),
1231            buffer_changed_since_sync,
1232        }
1233    }
1234
1235    pub fn set_group_interval(&mut self, group_interval: Duration) {
1236        self.history.set_group_interval(group_interval);
1237    }
1238
1239    pub fn with_title(mut self, title: String) -> Self {
1240        self.title = Some(title);
1241        self
1242    }
1243
1244    pub fn read_only(&self) -> bool {
1245        !self.capability.editable()
1246    }
1247
1248    pub fn capability(&self) -> Capability {
1249        self.capability
1250    }
1251
1252    /// Returns an up-to-date snapshot of the MultiBuffer.
1253    #[ztracing::instrument(skip_all)]
1254    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1255        self.sync(cx);
1256        self.snapshot.borrow().clone()
1257    }
1258
1259    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1260        self.sync(cx);
1261        self.snapshot.borrow()
1262    }
1263
1264    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1265        if self.singleton {
1266            Some(self.buffers.values().next().unwrap().buffer.clone())
1267        } else {
1268            None
1269        }
1270    }
1271
1272    pub fn is_singleton(&self) -> bool {
1273        self.singleton
1274    }
1275
1276    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1277        self.subscriptions.subscribe()
1278    }
1279
1280    pub fn is_dirty(&self, cx: &App) -> bool {
1281        self.read(cx).is_dirty()
1282    }
1283
1284    pub fn has_deleted_file(&self, cx: &App) -> bool {
1285        self.read(cx).has_deleted_file()
1286    }
1287
1288    pub fn has_conflict(&self, cx: &App) -> bool {
1289        self.read(cx).has_conflict()
1290    }
1291
1292    // The `is_empty` signature doesn't match what clippy expects
1293    #[allow(clippy::len_without_is_empty)]
1294    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1295        self.read(cx).len()
1296    }
1297
1298    pub fn is_empty(&self) -> bool {
1299        self.buffers.is_empty()
1300    }
1301
1302    pub fn edit<I, S, T>(
1303        &mut self,
1304        edits: I,
1305        autoindent_mode: Option<AutoindentMode>,
1306        cx: &mut Context<Self>,
1307    ) where
1308        I: IntoIterator<Item = (Range<S>, T)>,
1309        S: ToOffset,
1310        T: Into<Arc<str>>,
1311    {
1312        self.edit_internal(edits, autoindent_mode, true, cx);
1313    }
1314
1315    pub fn edit_non_coalesce<I, S, T>(
1316        &mut self,
1317        edits: I,
1318        autoindent_mode: Option<AutoindentMode>,
1319        cx: &mut Context<Self>,
1320    ) where
1321        I: IntoIterator<Item = (Range<S>, T)>,
1322        S: ToOffset,
1323        T: Into<Arc<str>>,
1324    {
1325        self.edit_internal(edits, autoindent_mode, false, cx);
1326    }
1327
1328    fn edit_internal<I, S, T>(
1329        &mut self,
1330        edits: I,
1331        autoindent_mode: Option<AutoindentMode>,
1332        coalesce_adjacent: bool,
1333        cx: &mut Context<Self>,
1334    ) where
1335        I: IntoIterator<Item = (Range<S>, T)>,
1336        S: ToOffset,
1337        T: Into<Arc<str>>,
1338    {
1339        if self.read_only() || self.buffers.is_empty() {
1340            return;
1341        }
1342        self.sync_mut(cx);
1343        let edits = edits
1344            .into_iter()
1345            .map(|(range, new_text)| {
1346                let mut range = range.start.to_offset(self.snapshot.get_mut())
1347                    ..range.end.to_offset(self.snapshot.get_mut());
1348                if range.start > range.end {
1349                    mem::swap(&mut range.start, &mut range.end);
1350                }
1351                (range, new_text.into())
1352            })
1353            .collect::<Vec<_>>();
1354
1355        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1356
1357        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1358        fn edit_internal(
1359            this: &mut MultiBuffer,
1360            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1361            mut autoindent_mode: Option<AutoindentMode>,
1362            coalesce_adjacent: bool,
1363            cx: &mut Context<MultiBuffer>,
1364        ) {
1365            let original_indent_columns = match &mut autoindent_mode {
1366                Some(AutoindentMode::Block {
1367                    original_indent_columns,
1368                }) => mem::take(original_indent_columns),
1369                _ => Default::default(),
1370            };
1371
1372            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1373                edits,
1374                this.snapshot.get_mut(),
1375                &original_indent_columns,
1376            );
1377
1378            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1379            for (buffer_id, mut edits) in buffer_edits {
1380                buffer_ids.push(buffer_id);
1381                edits.sort_by_key(|edit| edit.range.start);
1382                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1383                    let mut edits = edits.into_iter().peekable();
1384                    let mut insertions = Vec::new();
1385                    let mut original_indent_columns = Vec::new();
1386                    let mut deletions = Vec::new();
1387                    let empty_str: Arc<str> = Arc::default();
1388                    while let Some(BufferEdit {
1389                        mut range,
1390                        mut new_text,
1391                        mut is_insertion,
1392                        original_indent_column,
1393                        excerpt_id,
1394                    }) = edits.next()
1395                    {
1396                        while let Some(BufferEdit {
1397                            range: next_range,
1398                            is_insertion: next_is_insertion,
1399                            new_text: next_new_text,
1400                            excerpt_id: next_excerpt_id,
1401                            ..
1402                        }) = edits.peek()
1403                        {
1404                            let should_coalesce = if coalesce_adjacent {
1405                                range.end >= next_range.start
1406                            } else {
1407                                range.end > next_range.start
1408                            };
1409
1410                            if should_coalesce {
1411                                range.end = cmp::max(next_range.end, range.end);
1412                                is_insertion |= *next_is_insertion;
1413                                if excerpt_id == *next_excerpt_id {
1414                                    new_text = format!("{new_text}{next_new_text}").into();
1415                                }
1416                                edits.next();
1417                            } else {
1418                                break;
1419                            }
1420                        }
1421
1422                        if is_insertion {
1423                            original_indent_columns.push(original_indent_column);
1424                            insertions.push((
1425                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1426                                new_text.clone(),
1427                            ));
1428                        } else if !range.is_empty() {
1429                            deletions.push((
1430                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1431                                empty_str.clone(),
1432                            ));
1433                        }
1434                    }
1435
1436                    let deletion_autoindent_mode =
1437                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1438                            Some(AutoindentMode::Block {
1439                                original_indent_columns: Default::default(),
1440                            })
1441                        } else {
1442                            autoindent_mode.clone()
1443                        };
1444                    let insertion_autoindent_mode =
1445                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1446                            Some(AutoindentMode::Block {
1447                                original_indent_columns,
1448                            })
1449                        } else {
1450                            autoindent_mode.clone()
1451                        };
1452
1453                    if coalesce_adjacent {
1454                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1455                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1456                    } else {
1457                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1458                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1459                    }
1460                })
1461            }
1462
1463            cx.emit(Event::ExcerptsEdited {
1464                excerpt_ids: edited_excerpt_ids,
1465                buffer_ids,
1466            });
1467        }
1468    }
1469
1470    fn convert_edits_to_buffer_edits(
1471        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1472        snapshot: &MultiBufferSnapshot,
1473        original_indent_columns: &[Option<u32>],
1474    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1475        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1476        let mut edited_excerpt_ids = Vec::new();
1477        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1478        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1479            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1480
1481            cursor.seek(&range.start);
1482            let mut start_region = cursor.region().expect("start offset out of bounds");
1483            if !start_region.is_main_buffer {
1484                cursor.next();
1485                if let Some(region) = cursor.region() {
1486                    start_region = region;
1487                } else {
1488                    continue;
1489                }
1490            }
1491
1492            if range.end < start_region.range.start {
1493                continue;
1494            }
1495
1496            let start_region = start_region.clone();
1497            if range.end > start_region.range.end {
1498                cursor.seek_forward(&range.end);
1499            }
1500            let mut end_region = cursor.region().expect("end offset out of bounds");
1501            if !end_region.is_main_buffer {
1502                cursor.prev();
1503                if let Some(region) = cursor.region() {
1504                    end_region = region;
1505                } else {
1506                    continue;
1507                }
1508            }
1509
1510            if range.start > end_region.range.end {
1511                continue;
1512            }
1513
1514            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1515            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1516            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1517                .min(start_region.buffer_range.end);
1518            let buffer_end =
1519                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1520
1521            if start_region.excerpt.id == end_region.excerpt.id {
1522                if start_region.buffer.capability == Capability::ReadWrite
1523                    && start_region.is_main_buffer
1524                {
1525                    edited_excerpt_ids.push(start_region.excerpt.id);
1526                    buffer_edits
1527                        .entry(start_region.buffer.remote_id())
1528                        .or_default()
1529                        .push(BufferEdit {
1530                            range: buffer_start..buffer_end,
1531                            new_text,
1532                            is_insertion: true,
1533                            original_indent_column,
1534                            excerpt_id: start_region.excerpt.id,
1535                        });
1536                }
1537            } else {
1538                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1539                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1540                if start_region.buffer.capability == Capability::ReadWrite
1541                    && start_region.is_main_buffer
1542                {
1543                    edited_excerpt_ids.push(start_region.excerpt.id);
1544                    buffer_edits
1545                        .entry(start_region.buffer.remote_id())
1546                        .or_default()
1547                        .push(BufferEdit {
1548                            range: start_excerpt_range,
1549                            new_text: new_text.clone(),
1550                            is_insertion: true,
1551                            original_indent_column,
1552                            excerpt_id: start_region.excerpt.id,
1553                        });
1554                }
1555                let excerpt_id = end_region.excerpt.id;
1556                if end_region.buffer.capability == Capability::ReadWrite
1557                    && end_region.is_main_buffer
1558                {
1559                    edited_excerpt_ids.push(excerpt_id);
1560                    buffer_edits
1561                        .entry(end_region.buffer.remote_id())
1562                        .or_default()
1563                        .push(BufferEdit {
1564                            range: end_excerpt_range,
1565                            new_text: new_text.clone(),
1566                            is_insertion: false,
1567                            original_indent_column,
1568                            excerpt_id,
1569                        });
1570                }
1571
1572                cursor.seek(&range.start);
1573                cursor.next_excerpt();
1574                while let Some(region) = cursor.region() {
1575                    if region.excerpt.id == excerpt_id {
1576                        break;
1577                    }
1578                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1579                        edited_excerpt_ids.push(region.excerpt.id);
1580                        buffer_edits
1581                            .entry(region.buffer.remote_id())
1582                            .or_default()
1583                            .push(BufferEdit {
1584                                range: region.buffer_range.clone(),
1585                                new_text: new_text.clone(),
1586                                is_insertion: false,
1587                                original_indent_column,
1588                                excerpt_id: region.excerpt.id,
1589                            });
1590                    }
1591                    cursor.next_excerpt();
1592                }
1593            }
1594        }
1595        (buffer_edits, edited_excerpt_ids)
1596    }
1597
1598    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1599    where
1600        I: IntoIterator<Item = Range<S>>,
1601        S: ToOffset,
1602    {
1603        if self.read_only() || self.buffers.is_empty() {
1604            return;
1605        }
1606        self.sync_mut(cx);
1607        let empty = Arc::<str>::from("");
1608        let edits = ranges
1609            .into_iter()
1610            .map(|range| {
1611                let mut range = range.start.to_offset(self.snapshot.get_mut())
1612                    ..range.end.to_offset(&self.snapshot.get_mut());
1613                if range.start > range.end {
1614                    mem::swap(&mut range.start, &mut range.end);
1615                }
1616                (range, empty.clone())
1617            })
1618            .collect::<Vec<_>>();
1619
1620        return autoindent_ranges_internal(self, edits, cx);
1621
1622        fn autoindent_ranges_internal(
1623            this: &mut MultiBuffer,
1624            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1625            cx: &mut Context<MultiBuffer>,
1626        ) {
1627            let (buffer_edits, edited_excerpt_ids) =
1628                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1629
1630            let mut buffer_ids = Vec::new();
1631            for (buffer_id, mut edits) in buffer_edits {
1632                buffer_ids.push(buffer_id);
1633                edits.sort_unstable_by_key(|edit| edit.range.start);
1634
1635                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1636                for edit in edits {
1637                    if let Some(last_range) = ranges.last_mut()
1638                        && edit.range.start <= last_range.end
1639                    {
1640                        last_range.end = last_range.end.max(edit.range.end);
1641                        continue;
1642                    }
1643                    ranges.push(edit.range);
1644                }
1645
1646                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1647                    buffer.autoindent_ranges(ranges, cx);
1648                })
1649            }
1650
1651            cx.emit(Event::ExcerptsEdited {
1652                excerpt_ids: edited_excerpt_ids,
1653                buffer_ids,
1654            });
1655        }
1656    }
1657
1658    pub fn set_active_selections(
1659        &self,
1660        selections: &[Selection<Anchor>],
1661        line_mode: bool,
1662        cursor_shape: CursorShape,
1663        cx: &mut Context<Self>,
1664    ) {
1665        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1666            Default::default();
1667        let snapshot = self.read(cx);
1668        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1669        for selection in selections {
1670            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1671            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1672
1673            cursor.seek(&Some(start_locator), Bias::Left);
1674            while let Some(excerpt) = cursor.item()
1675                && excerpt.locator <= *end_locator
1676            {
1677                let mut start = excerpt.range.context.start;
1678                let mut end = excerpt.range.context.end;
1679                if excerpt.id == selection.start.excerpt_id {
1680                    start = selection.start.text_anchor;
1681                }
1682                if excerpt.id == selection.end.excerpt_id {
1683                    end = selection.end.text_anchor;
1684                }
1685                selections_by_buffer
1686                    .entry(excerpt.buffer_id)
1687                    .or_default()
1688                    .push(Selection {
1689                        id: selection.id,
1690                        start,
1691                        end,
1692                        reversed: selection.reversed,
1693                        goal: selection.goal,
1694                    });
1695
1696                cursor.next();
1697            }
1698        }
1699
1700        for (buffer_id, buffer_state) in self.buffers.iter() {
1701            if !selections_by_buffer.contains_key(buffer_id) {
1702                buffer_state
1703                    .buffer
1704                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1705            }
1706        }
1707
1708        for (buffer_id, mut selections) in selections_by_buffer {
1709            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1710                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1711                let mut selections = selections.into_iter().peekable();
1712                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1713                    let mut selection = selections.next()?;
1714                    while let Some(next_selection) = selections.peek() {
1715                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1716                            let next_selection = selections.next().unwrap();
1717                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1718                                selection.end = next_selection.end;
1719                            }
1720                        } else {
1721                            break;
1722                        }
1723                    }
1724                    Some(selection)
1725                }));
1726                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1727            });
1728        }
1729    }
1730
1731    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1732        for buffer in self.buffers.values() {
1733            buffer
1734                .buffer
1735                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1736        }
1737    }
1738
1739    pub fn push_excerpts<O>(
1740        &mut self,
1741        buffer: Entity<Buffer>,
1742        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1743        cx: &mut Context<Self>,
1744    ) -> Vec<ExcerptId>
1745    where
1746        O: text::ToOffset,
1747    {
1748        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1749    }
1750
1751    #[instrument(skip_all)]
1752    fn merge_excerpt_ranges<'a>(
1753        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1754    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1755        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1756        let mut counts: Vec<usize> = Vec::new();
1757        for range in expanded_ranges {
1758            if let Some(last_range) = merged_ranges.last_mut() {
1759                assert!(
1760                    last_range.context.start <= range.context.start,
1761                    "ranges must be sorted: {last_range:?} <= {range:?}"
1762                );
1763                if last_range.context.end >= range.context.start
1764                    || last_range.context.end.row + 1 == range.context.start.row
1765                {
1766                    last_range.context.end = range.context.end.max(last_range.context.end);
1767                    *counts.last_mut().unwrap() += 1;
1768                    continue;
1769                }
1770            }
1771            merged_ranges.push(range.clone());
1772            counts.push(1);
1773        }
1774        (merged_ranges, counts)
1775    }
1776
1777    pub fn insert_excerpts_after<O>(
1778        &mut self,
1779        prev_excerpt_id: ExcerptId,
1780        buffer: Entity<Buffer>,
1781        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1782        cx: &mut Context<Self>,
1783    ) -> Vec<ExcerptId>
1784    where
1785        O: text::ToOffset,
1786    {
1787        let mut ids = Vec::new();
1788        let mut next_excerpt_id =
1789            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1790                last_entry.id.0 + 1
1791            } else {
1792                1
1793            };
1794        self.insert_excerpts_with_ids_after(
1795            prev_excerpt_id,
1796            buffer,
1797            ranges.into_iter().map(|range| {
1798                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1799                ids.push(id);
1800                (id, range)
1801            }),
1802            cx,
1803        );
1804        ids
1805    }
1806
1807    pub fn insert_excerpts_with_ids_after<O>(
1808        &mut self,
1809        prev_excerpt_id: ExcerptId,
1810        buffer: Entity<Buffer>,
1811        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1812        cx: &mut Context<Self>,
1813    ) where
1814        O: text::ToOffset,
1815    {
1816        assert_eq!(self.history.transaction_depth(), 0);
1817        let mut ranges = ranges.into_iter().peekable();
1818        if ranges.peek().is_none() {
1819            return Default::default();
1820        }
1821
1822        self.sync_mut(cx);
1823
1824        let buffer_snapshot = buffer.read(cx).snapshot();
1825        let buffer_id = buffer_snapshot.remote_id();
1826
1827        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1828            self.buffer_changed_since_sync.replace(true);
1829            buffer.update(cx, |buffer, _| {
1830                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1831            });
1832            BufferState {
1833                last_version: RefCell::new(buffer_snapshot.version().clone()),
1834                last_non_text_state_update_count: Cell::new(
1835                    buffer_snapshot.non_text_state_update_count(),
1836                ),
1837                excerpts: Default::default(),
1838                _subscriptions: [
1839                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1840                    cx.subscribe(&buffer, Self::on_buffer_event),
1841                ],
1842                buffer: buffer.clone(),
1843            }
1844        });
1845
1846        let mut snapshot = self.snapshot.get_mut();
1847
1848        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1849        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1850        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1851        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1852        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1853
1854        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1855        new_excerpts.update_last(
1856            |excerpt| {
1857                excerpt.has_trailing_newline = true;
1858            },
1859            (),
1860        );
1861
1862        let next_locator = if let Some(excerpt) = cursor.item() {
1863            excerpt.locator.clone()
1864        } else {
1865            Locator::max()
1866        };
1867
1868        let mut excerpts = Vec::new();
1869        let buffer_snapshot = Arc::new(buffer_snapshot);
1870        while let Some((id, range)) = ranges.next() {
1871            let locator = Locator::between(&prev_locator, &next_locator);
1872            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1873                buffer_state.excerpts.insert(ix, locator.clone());
1874            }
1875            let range = ExcerptRange {
1876                context: buffer_snapshot.anchor_before(&range.context.start)
1877                    ..buffer_snapshot.anchor_after(&range.context.end),
1878                primary: buffer_snapshot.anchor_before(&range.primary.start)
1879                    ..buffer_snapshot.anchor_after(&range.primary.end),
1880            };
1881            excerpts.push((id, range.clone()));
1882            let excerpt = Excerpt::new(
1883                id,
1884                locator.clone(),
1885                buffer_id,
1886                buffer_snapshot.clone(),
1887                range,
1888                ranges.peek().is_some() || cursor.item().is_some(),
1889            );
1890            new_excerpts.push(excerpt, ());
1891            prev_locator = locator.clone();
1892
1893            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1894                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1895            }
1896            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1897        }
1898        snapshot
1899            .buffer_locators
1900            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1901
1902        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1903
1904        let suffix = cursor.suffix();
1905        let changed_trailing_excerpt = suffix.is_empty();
1906        new_excerpts.append(suffix, ());
1907        drop(cursor);
1908        snapshot.excerpts = new_excerpts;
1909        snapshot.excerpt_ids = new_excerpt_ids;
1910        if changed_trailing_excerpt {
1911            snapshot.trailing_excerpt_update_count += 1;
1912        }
1913
1914        let edits = Self::sync_diff_transforms(
1915            &mut snapshot,
1916            vec![Edit {
1917                old: edit_start..edit_start,
1918                new: edit_start..edit_end,
1919            }],
1920            DiffChangeKind::BufferEdited,
1921        );
1922        if !edits.is_empty() {
1923            self.subscriptions.publish(edits);
1924        }
1925
1926        cx.emit(Event::Edited {
1927            edited_buffer: None,
1928        });
1929        cx.emit(Event::ExcerptsAdded {
1930            buffer,
1931            predecessor: prev_excerpt_id,
1932            excerpts,
1933        });
1934        cx.notify();
1935    }
1936
1937    pub fn clear(&mut self, cx: &mut Context<Self>) {
1938        self.sync_mut(cx);
1939        let ids = self.excerpt_ids();
1940        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1941        self.excerpts_by_path.clear();
1942        self.paths_by_excerpt.clear();
1943        let MultiBufferSnapshot {
1944            excerpts,
1945            buffer_locators,
1946            diffs: _,
1947            diff_transforms: _,
1948            non_text_state_update_count: _,
1949            edit_count: _,
1950            is_dirty,
1951            has_deleted_file,
1952            has_conflict,
1953            has_inverted_diff,
1954            singleton: _,
1955            excerpt_ids: _,
1956            replaced_excerpts,
1957            trailing_excerpt_update_count,
1958            all_diff_hunks_expanded: _,
1959            show_deleted_hunks: _,
1960            use_extended_diff_range: _,
1961            show_headers: _,
1962        } = self.snapshot.get_mut();
1963        buffer_locators.clear();
1964        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1965        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1966        *excerpts = Default::default();
1967        *trailing_excerpt_update_count += 1;
1968        *is_dirty = false;
1969        *has_deleted_file = false;
1970        *has_conflict = false;
1971        *has_inverted_diff = false;
1972        replaced_excerpts.clear();
1973
1974        let edits = Self::sync_diff_transforms(
1975            self.snapshot.get_mut(),
1976            vec![Edit {
1977                old: start..prev_len,
1978                new: start..start,
1979            }],
1980            DiffChangeKind::BufferEdited,
1981        );
1982        if !edits.is_empty() {
1983            self.subscriptions.publish(edits);
1984        }
1985        cx.emit(Event::Edited {
1986            edited_buffer: None,
1987        });
1988        cx.emit(Event::ExcerptsRemoved {
1989            ids,
1990            removed_buffer_ids,
1991        });
1992        cx.notify();
1993    }
1994
1995    #[ztracing::instrument(skip_all)]
1996    pub fn excerpts_for_buffer(
1997        &self,
1998        buffer_id: BufferId,
1999        cx: &App,
2000    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2001        let mut excerpts = Vec::new();
2002        let snapshot = self.read(cx);
2003        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
2004        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
2005            for locator in &**locators {
2006                cursor.seek_forward(&Some(locator), Bias::Left);
2007                if let Some(excerpt) = cursor.item()
2008                    && excerpt.locator == *locator
2009                {
2010                    excerpts.push((excerpt.id, excerpt.range.clone()));
2011                }
2012            }
2013        }
2014
2015        excerpts
2016    }
2017
2018    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2019        let snapshot = self.read(cx);
2020        let mut excerpts = snapshot
2021            .excerpts
2022            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2023        let mut diff_transforms = snapshot
2024            .diff_transforms
2025            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2026        diff_transforms.next();
2027        let locators = snapshot
2028            .buffer_locators
2029            .get(&buffer_id)
2030            .into_iter()
2031            .flat_map(|v| &**v);
2032        let mut result = Vec::new();
2033        for locator in locators {
2034            excerpts.seek_forward(&Some(locator), Bias::Left);
2035            if let Some(excerpt) = excerpts.item()
2036                && excerpt.locator == *locator
2037            {
2038                let excerpt_start = excerpts.start().1;
2039                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2040
2041                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2042                let overshoot = excerpt_start - diff_transforms.start().0;
2043                let start = diff_transforms.start().1 + overshoot;
2044
2045                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2046                let overshoot = excerpt_end - diff_transforms.start().0;
2047                let end = diff_transforms.start().1 + overshoot;
2048
2049                result.push(start.0..end.0)
2050            }
2051        }
2052        result
2053    }
2054
2055    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2056        self.snapshot
2057            .borrow()
2058            .excerpts
2059            .iter()
2060            .map(|entry| entry.buffer_id)
2061            .collect()
2062    }
2063
2064    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2065        let snapshot = self.snapshot.borrow();
2066        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2067        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2068        ids
2069    }
2070
2071    pub fn excerpt_containing(
2072        &self,
2073        position: impl ToOffset,
2074        cx: &App,
2075    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2076        let snapshot = self.read(cx);
2077        let offset = position.to_offset(&snapshot);
2078
2079        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2080        cursor.seek(&offset);
2081        cursor
2082            .excerpt()
2083            .or_else(|| snapshot.excerpts.last())
2084            .map(|excerpt| {
2085                (
2086                    excerpt.id,
2087                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2088                    excerpt.range.context.clone(),
2089                )
2090            })
2091    }
2092
2093    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2094        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2095            self.buffer(buffer_id)
2096        } else {
2097            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2098            Some(buffer)
2099        }
2100    }
2101
2102    // If point is at the end of the buffer, the last excerpt is returned
2103    pub fn point_to_buffer_offset<T: ToOffset>(
2104        &self,
2105        point: T,
2106        cx: &App,
2107    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2108        let snapshot = self.read(cx);
2109        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2110        Some((
2111            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2112            offset,
2113        ))
2114    }
2115
2116    // If point is at the end of the buffer, the last excerpt is returned
2117    pub fn point_to_buffer_point<T: ToPoint>(
2118        &self,
2119        point: T,
2120        cx: &App,
2121    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2122        let snapshot = self.read(cx);
2123        let (buffer, point, is_main_buffer) =
2124            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2125        Some((
2126            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2127            point,
2128            is_main_buffer,
2129        ))
2130    }
2131
2132    pub fn buffer_point_to_anchor(
2133        &self,
2134        // todo(lw): We shouldn't need this?
2135        buffer: &Entity<Buffer>,
2136        point: Point,
2137        cx: &App,
2138    ) -> Option<Anchor> {
2139        let mut found = None;
2140        let snapshot = buffer.read(cx).snapshot();
2141        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2142            let start = range.context.start.to_point(&snapshot);
2143            let end = range.context.end.to_point(&snapshot);
2144            if start <= point && point < end {
2145                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2146                break;
2147            }
2148            if point < start {
2149                found = Some((start, excerpt_id));
2150            }
2151            if point > end {
2152                found = Some((end, excerpt_id));
2153            }
2154        }
2155
2156        found.map(|(point, excerpt_id)| {
2157            let text_anchor = snapshot.anchor_after(point);
2158            Anchor::in_buffer(excerpt_id, text_anchor)
2159        })
2160    }
2161
2162    pub fn buffer_anchor_to_anchor(
2163        &self,
2164        // todo(lw): We shouldn't need this?
2165        buffer: &Entity<Buffer>,
2166        anchor: text::Anchor,
2167        cx: &App,
2168    ) -> Option<Anchor> {
2169        let snapshot = buffer.read(cx).snapshot();
2170        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2171            if range.context.start.cmp(&anchor, &snapshot).is_le()
2172                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2173            {
2174                return Some(Anchor::in_buffer(excerpt_id, anchor));
2175            }
2176        }
2177
2178        None
2179    }
2180
2181    pub fn merge_excerpts(
2182        &mut self,
2183        excerpt_ids: &[ExcerptId],
2184        cx: &mut Context<Self>,
2185    ) -> ExcerptId {
2186        debug_assert!(!excerpt_ids.is_empty());
2187        if excerpt_ids.len() == 1 {
2188            return excerpt_ids[0];
2189        }
2190
2191        let snapshot = self.snapshot(cx);
2192
2193        let first_range = snapshot
2194            .context_range_for_excerpt(excerpt_ids[0])
2195            .expect("first excerpt must exist");
2196        let last_range = snapshot
2197            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2198            .expect("last excerpt must exist");
2199
2200        let union_range = first_range.start..last_range.end;
2201
2202        drop(snapshot);
2203
2204        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2205        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2206
2207        excerpt_ids[0]
2208    }
2209
2210    pub fn remove_excerpts(
2211        &mut self,
2212        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2213        cx: &mut Context<Self>,
2214    ) {
2215        self.sync_mut(cx);
2216        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2217        if ids.is_empty() {
2218            return;
2219        }
2220        self.buffer_changed_since_sync.replace(true);
2221
2222        let mut snapshot = self.snapshot.get_mut();
2223        let mut new_excerpts = SumTree::default();
2224        let mut cursor = snapshot
2225            .excerpts
2226            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2227        let mut edits = Vec::new();
2228        let mut excerpt_ids = ids.iter().copied().peekable();
2229        let mut removed_buffer_ids = Vec::new();
2230        let mut removed_excerpts_for_buffers = HashSet::default();
2231
2232        while let Some(excerpt_id) = excerpt_ids.next() {
2233            self.paths_by_excerpt.remove(&excerpt_id);
2234            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2235            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2236            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2237
2238            if let Some(mut excerpt) = cursor.item() {
2239                if excerpt.id != excerpt_id {
2240                    continue;
2241                }
2242                let mut old_start = cursor.start().1;
2243
2244                // Skip over the removed excerpt.
2245                'remove_excerpts: loop {
2246                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2247                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2248                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2249                        if buffer_state.excerpts.is_empty() {
2250                            log::debug!(
2251                                "removing buffer and diff for buffer {}",
2252                                excerpt.buffer_id
2253                            );
2254                            self.buffers.remove(&excerpt.buffer_id);
2255                            removed_buffer_ids.push(excerpt.buffer_id);
2256                        }
2257                    }
2258                    cursor.next();
2259
2260                    // Skip over any subsequent excerpts that are also removed.
2261                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2262                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2263                        if let Some(next_excerpt) = cursor.item()
2264                            && next_excerpt.locator == *next_locator
2265                        {
2266                            excerpt_ids.next();
2267                            excerpt = next_excerpt;
2268                            continue 'remove_excerpts;
2269                        }
2270                    }
2271
2272                    break;
2273                }
2274
2275                // When removing the last excerpt, remove the trailing newline from
2276                // the previous excerpt.
2277                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2278                    old_start -= 1;
2279                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2280                }
2281
2282                // Push an edit for the removal of this run of excerpts.
2283                let old_end = cursor.start().1;
2284                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2285                edits.push(Edit {
2286                    old: old_start..old_end,
2287                    new: new_start..new_start,
2288                });
2289            }
2290        }
2291        let suffix = cursor.suffix();
2292        let changed_trailing_excerpt = suffix.is_empty();
2293        new_excerpts.append(suffix, ());
2294        drop(cursor);
2295        for buffer_id in removed_excerpts_for_buffers {
2296            match self.buffers.get(&buffer_id) {
2297                Some(buffer_state) => {
2298                    snapshot
2299                        .buffer_locators
2300                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2301                }
2302                None => {
2303                    snapshot.buffer_locators.remove(&buffer_id);
2304                }
2305            }
2306        }
2307        snapshot.excerpts = new_excerpts;
2308        for buffer_id in &removed_buffer_ids {
2309            self.diffs.remove(buffer_id);
2310            snapshot.diffs.remove(buffer_id);
2311        }
2312
2313        // Recalculate has_inverted_diff after removing diffs
2314        if !removed_buffer_ids.is_empty() {
2315            snapshot.has_inverted_diff = snapshot
2316                .diffs
2317                .iter()
2318                .any(|(_, diff)| diff.main_buffer.is_some());
2319        }
2320
2321        if changed_trailing_excerpt {
2322            snapshot.trailing_excerpt_update_count += 1;
2323        }
2324
2325        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2326        if !edits.is_empty() {
2327            self.subscriptions.publish(edits);
2328        }
2329        cx.emit(Event::Edited {
2330            edited_buffer: None,
2331        });
2332        cx.emit(Event::ExcerptsRemoved {
2333            ids,
2334            removed_buffer_ids,
2335        });
2336        cx.notify();
2337    }
2338
2339    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2340        &self,
2341        anchors: Anchors,
2342        cx: &mut Context<Self>,
2343    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2344        let mut error = None;
2345        let mut futures = Vec::new();
2346        for anchor in anchors {
2347            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2348                if let Some(buffer) = self.buffers.get(&buffer_id) {
2349                    buffer.buffer.update(cx, |buffer, _| {
2350                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2351                    });
2352                } else {
2353                    error = Some(anyhow!(
2354                        "buffer {buffer_id} is not part of this multi-buffer"
2355                    ));
2356                    break;
2357                }
2358            }
2359        }
2360        async move {
2361            if let Some(error) = error {
2362                Err(error)?;
2363            }
2364            for future in futures {
2365                future.await?;
2366            }
2367            Ok(())
2368        }
2369    }
2370
2371    pub fn text_anchor_for_position<T: ToOffset>(
2372        &self,
2373        position: T,
2374        cx: &App,
2375    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2376        let snapshot = self.read(cx);
2377        let anchor = snapshot.anchor_before(position);
2378        let buffer = self
2379            .buffers
2380            .get(&anchor.text_anchor.buffer_id?)?
2381            .buffer
2382            .clone();
2383        Some((buffer, anchor.text_anchor))
2384    }
2385
2386    fn on_buffer_event(
2387        &mut self,
2388        buffer: Entity<Buffer>,
2389        event: &language::BufferEvent,
2390        cx: &mut Context<Self>,
2391    ) {
2392        use language::BufferEvent;
2393        let buffer_id = buffer.read(cx).remote_id();
2394        cx.emit(match event {
2395            BufferEvent::Edited => Event::Edited {
2396                edited_buffer: Some(buffer),
2397            },
2398            BufferEvent::DirtyChanged => Event::DirtyChanged,
2399            BufferEvent::Saved => Event::Saved,
2400            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2401            BufferEvent::Reloaded => Event::Reloaded,
2402            BufferEvent::LanguageChanged(has_language) => {
2403                Event::LanguageChanged(buffer_id, *has_language)
2404            }
2405            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2406            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2407            BufferEvent::CapabilityChanged => {
2408                self.capability = buffer.read(cx).capability();
2409                return;
2410            }
2411            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2412        });
2413    }
2414
2415    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2416        let diff = diff.read(cx);
2417        let buffer_id = diff.buffer_id;
2418        let diff = DiffStateSnapshot {
2419            diff: diff.snapshot(cx),
2420            main_buffer: None,
2421        };
2422        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2423    }
2424
2425    fn inverted_buffer_diff_language_changed(
2426        &mut self,
2427        diff: Entity<BufferDiff>,
2428        main_buffer: Entity<language::Buffer>,
2429        cx: &mut Context<Self>,
2430    ) {
2431        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2432        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2433        let diff = diff.read(cx);
2434        let diff = DiffStateSnapshot {
2435            diff: diff.snapshot(cx),
2436            main_buffer: Some(main_buffer_snapshot),
2437        };
2438        self.snapshot
2439            .get_mut()
2440            .diffs
2441            .insert(base_text_buffer_id, diff);
2442    }
2443
2444    fn buffer_diff_changed(
2445        &mut self,
2446        diff: Entity<BufferDiff>,
2447        range: Range<text::Anchor>,
2448        cx: &mut Context<Self>,
2449    ) {
2450        self.sync_mut(cx);
2451
2452        let diff = diff.read(cx);
2453        let buffer_id = diff.buffer_id;
2454
2455        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2456            return;
2457        };
2458        let new_diff = DiffStateSnapshot {
2459            diff: diff.snapshot(cx),
2460            main_buffer: None,
2461        };
2462        let mut snapshot = self.snapshot.get_mut();
2463        let base_text_changed = snapshot
2464            .diffs
2465            .get(&buffer_id)
2466            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2467        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2468
2469        let buffer = buffer_state.buffer.read(cx);
2470        let diff_change_range = range.to_offset(buffer);
2471
2472        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2473        let edits = Self::sync_diff_transforms(
2474            &mut snapshot,
2475            excerpt_edits,
2476            DiffChangeKind::DiffUpdated {
2477                base_changed: base_text_changed,
2478            },
2479        );
2480        if !edits.is_empty() {
2481            self.subscriptions.publish(edits);
2482        }
2483        cx.emit(Event::Edited {
2484            edited_buffer: None,
2485        });
2486    }
2487
2488    fn inverted_buffer_diff_changed(
2489        &mut self,
2490        diff: Entity<BufferDiff>,
2491        main_buffer: Entity<language::Buffer>,
2492        diff_change_range: Range<usize>,
2493        cx: &mut Context<Self>,
2494    ) {
2495        self.sync_mut(cx);
2496
2497        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2498        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2499            return;
2500        };
2501
2502        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2503        let diff = diff.read(cx);
2504        let new_diff = DiffStateSnapshot {
2505            diff: diff.snapshot(cx),
2506            main_buffer: Some(main_buffer_snapshot),
2507        };
2508        let mut snapshot = self.snapshot.get_mut();
2509        snapshot
2510            .diffs
2511            .insert_or_replace(base_text_buffer_id, new_diff);
2512
2513        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2514        let edits = Self::sync_diff_transforms(
2515            &mut snapshot,
2516            excerpt_edits,
2517            DiffChangeKind::DiffUpdated {
2518                // We don't read this field for inverted diffs.
2519                base_changed: false,
2520            },
2521        );
2522        if !edits.is_empty() {
2523            self.subscriptions.publish(edits);
2524        }
2525        cx.emit(Event::Edited {
2526            edited_buffer: None,
2527        });
2528    }
2529
2530    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2531        self.buffers.values().map(|state| state.buffer.clone())
2532    }
2533
2534    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2535        self.all_buffers_iter().collect()
2536    }
2537
2538    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2539        self.buffers.keys().copied()
2540    }
2541
2542    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2543        self.all_buffer_ids_iter().collect()
2544    }
2545
2546    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2547        self.buffers
2548            .get(&buffer_id)
2549            .map(|state| state.buffer.clone())
2550    }
2551
2552    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2553        self.point_to_buffer_offset(point, cx)
2554            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2555    }
2556
2557    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2558        let buffer_id = self
2559            .snapshot
2560            .borrow()
2561            .excerpts
2562            .first()
2563            .map(|excerpt| excerpt.buffer.remote_id());
2564        buffer_id
2565            .and_then(|buffer_id| self.buffer(buffer_id))
2566            .map(|buffer| {
2567                let buffer = buffer.read(cx);
2568                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2569            })
2570            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2571    }
2572
2573    pub fn language_settings_at<'a, T: ToOffset>(
2574        &'a self,
2575        point: T,
2576        cx: &'a App,
2577    ) -> Cow<'a, LanguageSettings> {
2578        let mut language = None;
2579        let mut file = None;
2580        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2581            let buffer = buffer.read(cx);
2582            language = buffer.language_at(offset);
2583            file = buffer.file();
2584        }
2585        language_settings(language.map(|l| l.name()), file, cx)
2586    }
2587
2588    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2589        self.buffers.values().for_each(|state| f(&state.buffer))
2590    }
2591
2592    pub fn explicit_title(&self) -> Option<&str> {
2593        self.title.as_deref()
2594    }
2595
2596    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2597        if let Some(title) = self.title.as_ref() {
2598            return title.into();
2599        }
2600
2601        if let Some(buffer) = self.as_singleton() {
2602            let buffer = buffer.read(cx);
2603
2604            if let Some(file) = buffer.file() {
2605                return file.file_name(cx).into();
2606            }
2607
2608            if let Some(title) = self.buffer_content_title(buffer) {
2609                return title;
2610            }
2611        };
2612
2613        "untitled".into()
2614    }
2615
2616    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2617        let mut is_leading_whitespace = true;
2618        let mut count = 0;
2619        let mut prev_was_space = false;
2620        let mut title = String::new();
2621
2622        for ch in buffer.snapshot().chars() {
2623            if is_leading_whitespace && ch.is_whitespace() {
2624                continue;
2625            }
2626
2627            is_leading_whitespace = false;
2628
2629            if ch == '\n' || count >= 40 {
2630                break;
2631            }
2632
2633            if ch.is_whitespace() {
2634                if !prev_was_space {
2635                    title.push(' ');
2636                    count += 1;
2637                    prev_was_space = true;
2638                }
2639            } else {
2640                title.push(ch);
2641                count += 1;
2642                prev_was_space = false;
2643            }
2644        }
2645
2646        let title = title.trim_end().to_string();
2647
2648        if title.is_empty() {
2649            return None;
2650        }
2651
2652        Some(title.into())
2653    }
2654
2655    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2656        self.title = Some(title);
2657        cx.notify();
2658    }
2659
2660    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2661    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2662        for buffer_state in self.buffers.values() {
2663            buffer_state
2664                .buffer
2665                .update(cx, |buffer, _cx| buffer.refresh_preview());
2666        }
2667    }
2668
2669    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2670    pub fn preserve_preview(&self, cx: &App) -> bool {
2671        self.buffers
2672            .values()
2673            .all(|state| state.buffer.read(cx).preserve_preview())
2674    }
2675
2676    #[cfg(any(test, feature = "test-support"))]
2677    pub fn is_parsing(&self, cx: &App) -> bool {
2678        self.as_singleton().unwrap().read(cx).is_parsing()
2679    }
2680
2681    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2682        let buffer_id = diff.read(cx).buffer_id;
2683
2684        if let Some(existing_diff) = self.diff_for(buffer_id)
2685            && diff.entity_id() == existing_diff.entity_id()
2686        {
2687            return;
2688        }
2689
2690        self.buffer_diff_changed(
2691            diff.clone(),
2692            text::Anchor::min_max_range_for_buffer(buffer_id),
2693            cx,
2694        );
2695        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2696    }
2697
2698    pub fn add_inverted_diff(
2699        &mut self,
2700        diff: Entity<BufferDiff>,
2701        main_buffer: Entity<language::Buffer>,
2702        cx: &mut Context<Self>,
2703    ) {
2704        let snapshot = diff.read(cx).base_text(cx);
2705        let base_text_buffer_id = snapshot.remote_id();
2706        let diff_change_range = 0..snapshot.len();
2707        self.snapshot.get_mut().has_inverted_diff = true;
2708        self.inverted_buffer_diff_changed(diff.clone(), main_buffer.clone(), diff_change_range, cx);
2709        self.diffs.insert(
2710            base_text_buffer_id,
2711            DiffState::new_inverted(diff, main_buffer, cx),
2712        );
2713    }
2714
2715    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2716        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2717    }
2718
2719    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2720        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2721    }
2722
2723    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2724        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2725    }
2726
2727    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2728        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2729        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2730    }
2731
2732    pub fn all_diff_hunks_expanded(&self) -> bool {
2733        self.snapshot.borrow().all_diff_hunks_expanded
2734    }
2735
2736    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2737        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2738        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2739    }
2740
2741    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2742        self.snapshot.get_mut().show_deleted_hunks = show;
2743
2744        self.sync_mut(cx);
2745
2746        let old_len = self.snapshot.borrow().len();
2747
2748        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2749        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2750
2751        let new_len = self.snapshot.borrow().len();
2752
2753        self.subscriptions.publish(vec![Edit {
2754            old: MultiBufferOffset(0)..old_len,
2755            new: MultiBufferOffset(0)..new_len,
2756        }]);
2757
2758        cx.emit(Event::DiffHunksToggled);
2759        cx.emit(Event::Edited {
2760            edited_buffer: None,
2761        });
2762    }
2763
2764    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2765        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2766    }
2767
2768    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2769        self.read(cx)
2770            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2771            .nth(1)
2772            .is_some()
2773    }
2774
2775    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2776        let snapshot = self.read(cx);
2777        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2778        let offset_range = range.to_offset(&snapshot);
2779        cursor.seek(&offset_range.start, Bias::Left);
2780        while let Some(item) = cursor.item() {
2781            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2782                break;
2783            }
2784            if item.hunk_info().is_some() {
2785                return true;
2786            }
2787            cursor.next();
2788        }
2789        false
2790    }
2791
2792    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2793        let snapshot = self.read(cx);
2794        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2795        for range in ranges {
2796            let range = range.to_point(&snapshot);
2797            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2798            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2799                .min(snapshot.len());
2800            cursor.seek(&start, Bias::Right);
2801            while let Some(item) = cursor.item() {
2802                if *cursor.start() >= end {
2803                    break;
2804                }
2805                if item.hunk_info().is_some() {
2806                    return true;
2807                }
2808                cursor.next();
2809            }
2810        }
2811        false
2812    }
2813
2814    pub fn expand_or_collapse_diff_hunks_inner(
2815        &mut self,
2816        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2817        expand: bool,
2818        cx: &mut Context<Self>,
2819    ) -> Vec<Edit<MultiBufferOffset>> {
2820        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2821            return Vec::new();
2822        }
2823        self.sync_mut(cx);
2824        let mut snapshot = self.snapshot.get_mut();
2825        let mut excerpt_edits = Vec::new();
2826        let mut last_hunk_row = None;
2827        for (range, end_excerpt_id) in ranges {
2828            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2829                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2830                    continue;
2831                }
2832                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2833                    continue;
2834                }
2835                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2836                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2837                let start = snapshot.excerpt_offset_for_anchor(&start);
2838                let end = snapshot.excerpt_offset_for_anchor(&end);
2839                last_hunk_row = Some(diff_hunk.row_range.start);
2840                excerpt_edits.push(text::Edit {
2841                    old: start..end,
2842                    new: start..end,
2843                });
2844            }
2845        }
2846
2847        Self::sync_diff_transforms(
2848            &mut snapshot,
2849            excerpt_edits,
2850            DiffChangeKind::ExpandOrCollapseHunks { expand },
2851        )
2852    }
2853
2854    pub fn expand_or_collapse_diff_hunks(
2855        &mut self,
2856        ranges: Vec<Range<Anchor>>,
2857        expand: bool,
2858        cx: &mut Context<Self>,
2859    ) {
2860        let snapshot = self.snapshot.borrow().clone();
2861        let ranges = ranges.iter().map(move |range| {
2862            let end_excerpt_id = range.end.excerpt_id;
2863            let range = range.to_point(&snapshot);
2864            let mut peek_end = range.end;
2865            if range.end.row < snapshot.max_row().0 {
2866                peek_end = Point::new(range.end.row + 1, 0);
2867            };
2868            (range.start..peek_end, end_excerpt_id)
2869        });
2870        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2871        if !edits.is_empty() {
2872            self.subscriptions.publish(edits);
2873        }
2874        cx.emit(Event::DiffHunksToggled);
2875        cx.emit(Event::Edited {
2876            edited_buffer: None,
2877        });
2878    }
2879
2880    pub fn resize_excerpt(
2881        &mut self,
2882        id: ExcerptId,
2883        range: Range<text::Anchor>,
2884        cx: &mut Context<Self>,
2885    ) {
2886        self.sync_mut(cx);
2887
2888        let mut snapshot = self.snapshot.get_mut();
2889        let locator = snapshot.excerpt_locator_for_id(id);
2890        let mut new_excerpts = SumTree::default();
2891        let mut cursor = snapshot
2892            .excerpts
2893            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2894        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2895
2896        let prefix = cursor.slice(&Some(locator), Bias::Left);
2897        new_excerpts.append(prefix, ());
2898
2899        let mut excerpt = cursor.item().unwrap().clone();
2900        let old_text_len = excerpt.text_summary.len;
2901
2902        excerpt.range.context.start = range.start;
2903        excerpt.range.context.end = range.end;
2904        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2905
2906        excerpt.text_summary = excerpt
2907            .buffer
2908            .text_summary_for_range(excerpt.range.context.clone());
2909
2910        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2911        let old_start_offset = cursor.start().1;
2912        let new_text_len = excerpt.text_summary.len;
2913        let edit = Edit {
2914            old: old_start_offset..old_start_offset + old_text_len,
2915            new: new_start_offset..new_start_offset + new_text_len,
2916        };
2917
2918        if let Some(last_edit) = edits.last_mut() {
2919            if last_edit.old.end == edit.old.start {
2920                last_edit.old.end = edit.old.end;
2921                last_edit.new.end = edit.new.end;
2922            } else {
2923                edits.push(edit);
2924            }
2925        } else {
2926            edits.push(edit);
2927        }
2928
2929        new_excerpts.push(excerpt, ());
2930
2931        cursor.next();
2932
2933        new_excerpts.append(cursor.suffix(), ());
2934
2935        drop(cursor);
2936        snapshot.excerpts = new_excerpts;
2937
2938        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2939        if !edits.is_empty() {
2940            self.subscriptions.publish(edits);
2941        }
2942        cx.emit(Event::Edited {
2943            edited_buffer: None,
2944        });
2945        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2946        cx.notify();
2947    }
2948
2949    pub fn expand_excerpts(
2950        &mut self,
2951        ids: impl IntoIterator<Item = ExcerptId>,
2952        line_count: u32,
2953        direction: ExpandExcerptDirection,
2954        cx: &mut Context<Self>,
2955    ) {
2956        if line_count == 0 {
2957            return;
2958        }
2959        self.sync_mut(cx);
2960        if !self.excerpts_by_path.is_empty() {
2961            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2962            return;
2963        }
2964        let mut snapshot = self.snapshot.get_mut();
2965
2966        let ids = ids.into_iter().collect::<Vec<_>>();
2967        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2968        let mut new_excerpts = SumTree::default();
2969        let mut cursor = snapshot
2970            .excerpts
2971            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2972        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2973
2974        for locator in &locators {
2975            let prefix = cursor.slice(&Some(locator), Bias::Left);
2976            new_excerpts.append(prefix, ());
2977
2978            let mut excerpt = cursor.item().unwrap().clone();
2979            let old_text_len = excerpt.text_summary.len;
2980
2981            let up_line_count = if direction.should_expand_up() {
2982                line_count
2983            } else {
2984                0
2985            };
2986
2987            let start_row = excerpt
2988                .range
2989                .context
2990                .start
2991                .to_point(&excerpt.buffer)
2992                .row
2993                .saturating_sub(up_line_count);
2994            let start_point = Point::new(start_row, 0);
2995            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2996
2997            let down_line_count = if direction.should_expand_down() {
2998                line_count
2999            } else {
3000                0
3001            };
3002
3003            let mut end_point = excerpt.buffer.clip_point(
3004                excerpt.range.context.end.to_point(&excerpt.buffer)
3005                    + Point::new(down_line_count, 0),
3006                Bias::Left,
3007            );
3008            end_point.column = excerpt.buffer.line_len(end_point.row);
3009            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3010            excerpt.max_buffer_row = end_point.row;
3011
3012            excerpt.text_summary = excerpt
3013                .buffer
3014                .text_summary_for_range(excerpt.range.context.clone());
3015
3016            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3017            let old_start_offset = cursor.start().1;
3018            let new_text_len = excerpt.text_summary.len;
3019            let edit = Edit {
3020                old: old_start_offset..old_start_offset + old_text_len,
3021                new: new_start_offset..new_start_offset + new_text_len,
3022            };
3023
3024            if let Some(last_edit) = edits.last_mut() {
3025                if last_edit.old.end == edit.old.start {
3026                    last_edit.old.end = edit.old.end;
3027                    last_edit.new.end = edit.new.end;
3028                } else {
3029                    edits.push(edit);
3030                }
3031            } else {
3032                edits.push(edit);
3033            }
3034
3035            new_excerpts.push(excerpt, ());
3036
3037            cursor.next();
3038        }
3039
3040        new_excerpts.append(cursor.suffix(), ());
3041
3042        drop(cursor);
3043        snapshot.excerpts = new_excerpts;
3044
3045        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3046        if !edits.is_empty() {
3047            self.subscriptions.publish(edits);
3048        }
3049        cx.emit(Event::Edited {
3050            edited_buffer: None,
3051        });
3052        cx.emit(Event::ExcerptsExpanded { ids });
3053        cx.notify();
3054    }
3055
3056    #[ztracing::instrument(skip_all)]
3057    fn sync(&self, cx: &App) {
3058        let changed = self.buffer_changed_since_sync.replace(false);
3059        if !changed {
3060            return;
3061        }
3062        let edits = Self::sync_from_buffer_changes(
3063            &mut self.snapshot.borrow_mut(),
3064            &self.buffers,
3065            &self.diffs,
3066            cx,
3067        );
3068        if !edits.is_empty() {
3069            self.subscriptions.publish(edits);
3070        }
3071    }
3072
3073    fn sync_mut(&mut self, cx: &App) {
3074        let changed = self.buffer_changed_since_sync.replace(false);
3075        if !changed {
3076            return;
3077        }
3078        let edits =
3079            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3080
3081        if !edits.is_empty() {
3082            self.subscriptions.publish(edits);
3083        }
3084    }
3085
3086    fn sync_from_buffer_changes(
3087        snapshot: &mut MultiBufferSnapshot,
3088        buffers: &BTreeMap<BufferId, BufferState>,
3089        diffs: &HashMap<BufferId, DiffState>,
3090        cx: &App,
3091    ) -> Vec<Edit<MultiBufferOffset>> {
3092        let MultiBufferSnapshot {
3093            excerpts,
3094            buffer_locators: _,
3095            diffs: buffer_diff,
3096            diff_transforms: _,
3097            non_text_state_update_count,
3098            edit_count,
3099            is_dirty,
3100            has_deleted_file,
3101            has_conflict,
3102            has_inverted_diff: _,
3103            singleton: _,
3104            excerpt_ids: _,
3105            replaced_excerpts: _,
3106            trailing_excerpt_update_count: _,
3107            all_diff_hunks_expanded: _,
3108            show_deleted_hunks: _,
3109            use_extended_diff_range: _,
3110            show_headers: _,
3111        } = snapshot;
3112        *is_dirty = false;
3113        *has_deleted_file = false;
3114        *has_conflict = false;
3115
3116        if !diffs.is_empty() {
3117            let mut diffs_to_add = Vec::new();
3118            for (id, diff) in diffs {
3119                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3120                // and use the diff hunk base text ranges to compute diff transforms.
3121                // Those base text ranges are usize, so make sure if the base text changed
3122                // we also update the diff snapshot so that we don't use stale offsets
3123                if buffer_diff.get(id).is_none_or(|existing_diff| {
3124                    if existing_diff.main_buffer.is_none() {
3125                        return false;
3126                    }
3127                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3128                    base_text.remote_id() != existing_diff.base_text().remote_id()
3129                        || base_text
3130                            .version()
3131                            .changed_since(existing_diff.base_text().version())
3132                }) {
3133                    if diffs_to_add.capacity() == 0 {
3134                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3135                        // meaning re-allocations will be fairly expensive
3136                        diffs_to_add.reserve(diffs.len());
3137                    }
3138                    diffs_to_add.push((*id, diff.snapshot(cx)));
3139                }
3140            }
3141            buffer_diff.extend(diffs_to_add);
3142        }
3143
3144        let mut excerpts_to_edit = Vec::new();
3145        let mut non_text_state_updated = false;
3146        let mut edited = false;
3147        for buffer_state in buffers.values() {
3148            let buffer = buffer_state.buffer.read(cx);
3149            let version = buffer.version();
3150            let non_text_state_update_count = buffer.non_text_state_update_count();
3151
3152            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3153            let buffer_non_text_state_updated =
3154                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3155            if buffer_edited || buffer_non_text_state_updated {
3156                *buffer_state.last_version.borrow_mut() = version;
3157                buffer_state
3158                    .last_non_text_state_update_count
3159                    .set(non_text_state_update_count);
3160                excerpts_to_edit.extend(
3161                    buffer_state
3162                        .excerpts
3163                        .iter()
3164                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3165                );
3166            }
3167
3168            edited |= buffer_edited;
3169            non_text_state_updated |= buffer_non_text_state_updated;
3170            *is_dirty |= buffer.is_dirty();
3171            *has_deleted_file |= buffer
3172                .file()
3173                .is_some_and(|file| file.disk_state().is_deleted());
3174            *has_conflict |= buffer.has_conflict();
3175        }
3176        if edited {
3177            *edit_count += 1;
3178        }
3179        if non_text_state_updated {
3180            *non_text_state_update_count += 1;
3181        }
3182
3183        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3184
3185        let mut edits = Vec::new();
3186        let mut new_excerpts = SumTree::default();
3187        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3188
3189        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3190            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3191            let old_excerpt = cursor.item().unwrap();
3192            let buffer = buffer.read(cx);
3193            let buffer_id = buffer.remote_id();
3194            let mut new_excerpt;
3195            if buffer_edited {
3196                edits.extend(
3197                    buffer
3198                        .edits_since_in_range::<usize>(
3199                            old_excerpt.buffer.version(),
3200                            old_excerpt.range.context.clone(),
3201                        )
3202                        .map(|edit| {
3203                            let excerpt_old_start = cursor.start().1;
3204                            let excerpt_new_start =
3205                                ExcerptDimension(new_excerpts.summary().text.len);
3206                            let old_start = excerpt_old_start + edit.old.start;
3207                            let old_end = excerpt_old_start + edit.old.end;
3208                            let new_start = excerpt_new_start + edit.new.start;
3209                            let new_end = excerpt_new_start + edit.new.end;
3210                            Edit {
3211                                old: old_start..old_end,
3212                                new: new_start..new_end,
3213                            }
3214                        }),
3215                );
3216
3217                new_excerpt = Excerpt::new(
3218                    old_excerpt.id,
3219                    locator.clone(),
3220                    buffer_id,
3221                    Arc::new(buffer.snapshot()),
3222                    old_excerpt.range.clone(),
3223                    old_excerpt.has_trailing_newline,
3224                );
3225            } else {
3226                new_excerpt = old_excerpt.clone();
3227                new_excerpt.buffer = Arc::new(buffer.snapshot());
3228            }
3229
3230            new_excerpts.push(new_excerpt, ());
3231            cursor.next();
3232        }
3233        new_excerpts.append(cursor.suffix(), ());
3234
3235        drop(cursor);
3236        *excerpts = new_excerpts;
3237
3238        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3239    }
3240
3241    fn sync_diff_transforms(
3242        snapshot: &mut MultiBufferSnapshot,
3243        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3244        change_kind: DiffChangeKind,
3245    ) -> Vec<Edit<MultiBufferOffset>> {
3246        if excerpt_edits.is_empty() {
3247            return vec![];
3248        }
3249
3250        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3251        let mut old_diff_transforms = snapshot
3252            .diff_transforms
3253            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3254        let mut new_diff_transforms = SumTree::default();
3255        let mut old_expanded_hunks = HashSet::default();
3256        let mut output_edits = Vec::new();
3257        let mut output_delta = 0_isize;
3258        let mut at_transform_boundary = true;
3259        let mut end_of_current_insert = None;
3260
3261        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3262        while let Some(edit) = excerpt_edits.next() {
3263            excerpts.seek_forward(&edit.new.start, Bias::Right);
3264            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3265                excerpts.prev();
3266            }
3267
3268            // Keep any transforms that are before the edit.
3269            if at_transform_boundary {
3270                at_transform_boundary = false;
3271                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3272                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3273                if let Some(transform) = old_diff_transforms.item()
3274                    && old_diff_transforms.end().0 == edit.old.start
3275                    && old_diff_transforms.start().0 < edit.old.start
3276                {
3277                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3278                    old_diff_transforms.next();
3279                }
3280            }
3281
3282            // Compute the start of the edit in output coordinates.
3283            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3284            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3285            let edit_new_start =
3286                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3287
3288            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3289                &edit,
3290                &mut excerpts,
3291                &mut old_diff_transforms,
3292                &mut new_diff_transforms,
3293                &mut end_of_current_insert,
3294                &mut old_expanded_hunks,
3295                snapshot,
3296                change_kind,
3297            );
3298
3299            // Compute the end of the edit in output coordinates.
3300            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3301            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3302            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3303            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3304            let output_edit = Edit {
3305                old: edit_old_start..edit_old_end,
3306                new: edit_new_start..edit_new_end,
3307            };
3308
3309            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3310            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3311            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3312                output_edits.push(output_edit);
3313            }
3314
3315            // If this is the last edit that intersects the current diff transform,
3316            // then recreate the content up to the end of this transform, to prepare
3317            // for reusing additional slices of the old transforms.
3318            if excerpt_edits
3319                .peek()
3320                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3321            {
3322                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3323                    && match old_diff_transforms.item() {
3324                        Some(DiffTransform::BufferContent {
3325                            inserted_hunk_info: Some(hunk),
3326                            ..
3327                        }) => excerpts.item().is_some_and(|excerpt| {
3328                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3329                                && diff.main_buffer.is_some()
3330                            {
3331                                return true;
3332                            }
3333                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3334                        }),
3335                        _ => true,
3336                    };
3337
3338                let mut excerpt_offset = edit.new.end;
3339                if !keep_next_old_transform {
3340                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3341                    old_diff_transforms.next();
3342                }
3343
3344                old_expanded_hunks.clear();
3345                Self::push_buffer_content_transform(
3346                    snapshot,
3347                    &mut new_diff_transforms,
3348                    excerpt_offset,
3349                    end_of_current_insert,
3350                );
3351                at_transform_boundary = true;
3352            }
3353        }
3354
3355        // Keep any transforms that are after the last edit.
3356        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3357
3358        // Ensure there's always at least one buffer content transform.
3359        if new_diff_transforms.is_empty() {
3360            new_diff_transforms.push(
3361                DiffTransform::BufferContent {
3362                    summary: Default::default(),
3363                    inserted_hunk_info: None,
3364                },
3365                (),
3366            );
3367        }
3368
3369        drop(old_diff_transforms);
3370        drop(excerpts);
3371        snapshot.diff_transforms = new_diff_transforms;
3372        snapshot.edit_count += 1;
3373
3374        #[cfg(any(test, feature = "test-support"))]
3375        snapshot.check_invariants();
3376        output_edits
3377    }
3378
3379    fn recompute_diff_transforms_for_edit(
3380        edit: &Edit<ExcerptOffset>,
3381        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3382        old_diff_transforms: &mut Cursor<
3383            DiffTransform,
3384            Dimensions<ExcerptOffset, MultiBufferOffset>,
3385        >,
3386        new_diff_transforms: &mut SumTree<DiffTransform>,
3387        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3388        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3389        snapshot: &MultiBufferSnapshot,
3390        change_kind: DiffChangeKind,
3391    ) -> bool {
3392        log::trace!(
3393            "recomputing diff transform for edit {:?} => {:?}",
3394            edit.old.start..edit.old.end,
3395            edit.new.start..edit.new.end
3396        );
3397
3398        // Record which hunks were previously expanded.
3399        while let Some(item) = old_diff_transforms.item() {
3400            if let Some(hunk_info) = item.hunk_info() {
3401                log::trace!(
3402                    "previously expanded hunk at {:?}",
3403                    old_diff_transforms.start()
3404                );
3405                old_expanded_hunks.insert(hunk_info);
3406            }
3407            if old_diff_transforms.end().0 > edit.old.end {
3408                break;
3409            }
3410            old_diff_transforms.next();
3411        }
3412
3413        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3414        // For inverted diffs, hunks are always shown, so we can't skip this.
3415        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3416        if old_expanded_hunks.is_empty()
3417            && change_kind == DiffChangeKind::BufferEdited
3418            && !all_diff_hunks_expanded
3419            && !snapshot.has_inverted_diff
3420        {
3421            return false;
3422        }
3423
3424        // Visit each excerpt that intersects the edit.
3425        let mut did_expand_hunks = false;
3426        while let Some(excerpt) = excerpts.item() {
3427            // Recompute the expanded hunks in the portion of the excerpt that
3428            // intersects the edit.
3429            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3430                let buffer = &excerpt.buffer;
3431                let excerpt_start = *excerpts.start();
3432                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3433                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3434                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3435                let edit_buffer_start =
3436                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3437                let edit_buffer_end =
3438                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3439                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3440
3441                if let Some(main_buffer) = &diff.main_buffer {
3442                    for hunk in diff.hunks_intersecting_base_text_range(
3443                        edit_buffer_start..edit_buffer_end,
3444                        main_buffer,
3445                    ) {
3446                        did_expand_hunks = true;
3447                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3448                        if hunk_buffer_range.start < excerpt_buffer_start {
3449                            log::trace!("skipping hunk that starts before excerpt");
3450                            continue;
3451                        }
3452                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3453                        let hunk_excerpt_start = excerpt_start
3454                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3455                        let hunk_excerpt_end = excerpt_end
3456                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3457                        Self::push_buffer_content_transform(
3458                            snapshot,
3459                            new_diff_transforms,
3460                            hunk_excerpt_start,
3461                            *end_of_current_insert,
3462                        );
3463                        if !hunk_buffer_range.is_empty() {
3464                            let hunk_info = DiffTransformHunkInfo {
3465                                excerpt_id: excerpt.id,
3466                                hunk_start_anchor: hunk.buffer_range.start,
3467                                hunk_secondary_status: hunk.secondary_status,
3468                                is_logically_deleted: true,
3469                            };
3470                            *end_of_current_insert =
3471                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3472                        }
3473                    }
3474                } else {
3475                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3476                        ..buffer.anchor_after(edit_buffer_end);
3477                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3478                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3479                            continue;
3480                        }
3481
3482                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3483                        if hunk_buffer_range.start < excerpt_buffer_start {
3484                            log::trace!("skipping hunk that starts before excerpt");
3485                            continue;
3486                        }
3487
3488                        let hunk_info = DiffTransformHunkInfo {
3489                            excerpt_id: excerpt.id,
3490                            hunk_start_anchor: hunk.buffer_range.start,
3491                            hunk_secondary_status: hunk.secondary_status,
3492                            is_logically_deleted: false,
3493                        };
3494
3495                        let hunk_excerpt_start = excerpt_start
3496                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3497                        let hunk_excerpt_end = excerpt_end
3498                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3499
3500                        Self::push_buffer_content_transform(
3501                            snapshot,
3502                            new_diff_transforms,
3503                            hunk_excerpt_start,
3504                            *end_of_current_insert,
3505                        );
3506
3507                        // For every existing hunk, determine if it was previously expanded
3508                        // and if it should currently be expanded.
3509                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3510                        let should_expand_hunk = match &change_kind {
3511                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3512                                was_previously_expanded || all_diff_hunks_expanded
3513                            }
3514                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3515                                let intersects = hunk_buffer_range.is_empty()
3516                                    || hunk_buffer_range.end > edit_buffer_start;
3517                                if *expand {
3518                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3519                                } else {
3520                                    !intersects
3521                                        && (was_previously_expanded || all_diff_hunks_expanded)
3522                                }
3523                            }
3524                            _ => was_previously_expanded || all_diff_hunks_expanded,
3525                        };
3526
3527                        if should_expand_hunk {
3528                            did_expand_hunks = true;
3529                            log::trace!(
3530                                "expanding hunk {:?}, excerpt:{:?}",
3531                                hunk_excerpt_start..hunk_excerpt_end,
3532                                excerpt.id
3533                            );
3534
3535                            if !hunk.diff_base_byte_range.is_empty()
3536                                && hunk_buffer_range.start >= edit_buffer_start
3537                                && hunk_buffer_range.start <= excerpt_buffer_end
3538                                && snapshot.show_deleted_hunks
3539                            {
3540                                let base_text = diff.base_text();
3541                                let mut text_cursor =
3542                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3543                                let mut base_text_summary = text_cursor
3544                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3545
3546                                let mut has_trailing_newline = false;
3547                                if base_text_summary.last_line_chars > 0 {
3548                                    base_text_summary += TextSummary::newline();
3549                                    has_trailing_newline = true;
3550                                }
3551
3552                                new_diff_transforms.push(
3553                                    DiffTransform::DeletedHunk {
3554                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3555                                        summary: base_text_summary,
3556                                        buffer_id: excerpt.buffer_id,
3557                                        hunk_info,
3558                                        has_trailing_newline,
3559                                    },
3560                                    (),
3561                                );
3562                            }
3563
3564                            if !hunk_buffer_range.is_empty() {
3565                                *end_of_current_insert =
3566                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3567                            }
3568                        }
3569                    }
3570                }
3571            }
3572
3573            if excerpts.end() <= edit.new.end {
3574                excerpts.next();
3575            } else {
3576                break;
3577            }
3578        }
3579
3580        did_expand_hunks || !old_expanded_hunks.is_empty()
3581    }
3582
3583    fn append_diff_transforms(
3584        new_transforms: &mut SumTree<DiffTransform>,
3585        subtree: SumTree<DiffTransform>,
3586    ) {
3587        if let Some(DiffTransform::BufferContent {
3588            inserted_hunk_info,
3589            summary,
3590        }) = subtree.first()
3591            && Self::extend_last_buffer_content_transform(
3592                new_transforms,
3593                *inserted_hunk_info,
3594                *summary,
3595            )
3596        {
3597            let mut cursor = subtree.cursor::<()>(());
3598            cursor.next();
3599            cursor.next();
3600            new_transforms.append(cursor.suffix(), ());
3601            return;
3602        }
3603        new_transforms.append(subtree, ());
3604    }
3605
3606    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3607        if let DiffTransform::BufferContent {
3608            inserted_hunk_info: inserted_hunk_anchor,
3609            summary,
3610        } = transform
3611            && Self::extend_last_buffer_content_transform(
3612                new_transforms,
3613                inserted_hunk_anchor,
3614                summary,
3615            )
3616        {
3617            return;
3618        }
3619        new_transforms.push(transform, ());
3620    }
3621
3622    fn push_buffer_content_transform(
3623        old_snapshot: &MultiBufferSnapshot,
3624        new_transforms: &mut SumTree<DiffTransform>,
3625        end_offset: ExcerptOffset,
3626        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3627    ) {
3628        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3629            (end_offset.min(insertion_end_offset), Some(hunk_info))
3630        });
3631        let unchanged_region = [(end_offset, None)];
3632
3633        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3634        {
3635            let start_offset = new_transforms.summary().excerpt_len();
3636            if end_offset <= start_offset {
3637                continue;
3638            }
3639            let summary_to_add = old_snapshot
3640                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3641
3642            if !Self::extend_last_buffer_content_transform(
3643                new_transforms,
3644                inserted_hunk_info,
3645                summary_to_add,
3646            ) {
3647                new_transforms.push(
3648                    DiffTransform::BufferContent {
3649                        summary: summary_to_add,
3650                        inserted_hunk_info,
3651                    },
3652                    (),
3653                )
3654            }
3655        }
3656    }
3657
3658    fn extend_last_buffer_content_transform(
3659        new_transforms: &mut SumTree<DiffTransform>,
3660        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3661        summary_to_add: MBTextSummary,
3662    ) -> bool {
3663        let mut did_extend = false;
3664        new_transforms.update_last(
3665            |last_transform| {
3666                if let DiffTransform::BufferContent {
3667                    summary,
3668                    inserted_hunk_info: inserted_hunk_anchor,
3669                } = last_transform
3670                    && *inserted_hunk_anchor == new_inserted_hunk_info
3671                {
3672                    *summary += summary_to_add;
3673                    did_extend = true;
3674                }
3675            },
3676            (),
3677        );
3678        did_extend
3679    }
3680
3681    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3682        let snapshot = self.snapshot(cx);
3683        let excerpt_id = range.end.excerpt_id;
3684        let point_range = range.to_point(&snapshot);
3685        let expand = !self.single_hunk_is_expanded(range, cx);
3686        let edits =
3687            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3688        if !edits.is_empty() {
3689            self.subscriptions.publish(edits);
3690        }
3691        cx.emit(Event::DiffHunksToggled);
3692        cx.emit(Event::Edited {
3693            edited_buffer: None,
3694        });
3695    }
3696}
3697
3698fn build_excerpt_ranges(
3699    ranges: impl IntoIterator<Item = Range<Point>>,
3700    context_line_count: u32,
3701    buffer_snapshot: &BufferSnapshot,
3702) -> Vec<ExcerptRange<Point>> {
3703    ranges
3704        .into_iter()
3705        .map(|range| {
3706            let start_row = range.start.row.saturating_sub(context_line_count);
3707            let start = Point::new(start_row, 0);
3708            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3709            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3710            ExcerptRange {
3711                context: start..end,
3712                primary: range,
3713            }
3714        })
3715        .collect()
3716}
3717
3718#[cfg(any(test, feature = "test-support"))]
3719impl MultiBuffer {
3720    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3721        let buffer = cx.new(|cx| Buffer::local(text, cx));
3722        cx.new(|cx| Self::singleton(buffer, cx))
3723    }
3724
3725    pub fn build_multi<const COUNT: usize>(
3726        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3727        cx: &mut gpui::App,
3728    ) -> Entity<Self> {
3729        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3730        for (text, ranges) in excerpts {
3731            let buffer = cx.new(|cx| Buffer::local(text, cx));
3732            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3733            multi.update(cx, |multi, cx| {
3734                multi.push_excerpts(buffer, excerpt_ranges, cx)
3735            });
3736        }
3737
3738        multi
3739    }
3740
3741    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3742        cx.new(|cx| Self::singleton(buffer, cx))
3743    }
3744
3745    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3746        cx.new(|cx| {
3747            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3748            let mutation_count = rng.random_range(1..=5);
3749            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3750            multibuffer
3751        })
3752    }
3753
3754    pub fn randomly_edit(
3755        &mut self,
3756        rng: &mut impl rand::Rng,
3757        edit_count: usize,
3758        cx: &mut Context<Self>,
3759    ) {
3760        use util::RandomCharIter;
3761
3762        let snapshot = self.read(cx);
3763        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3764        let mut last_end = None;
3765        for _ in 0..edit_count {
3766            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3767                break;
3768            }
3769
3770            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3771            let end =
3772                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3773            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3774            last_end = Some(end);
3775
3776            let mut range = start..end;
3777            if rng.random_bool(0.2) {
3778                mem::swap(&mut range.start, &mut range.end);
3779            }
3780
3781            let new_text_len = rng.random_range(0..10);
3782            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3783
3784            edits.push((range, new_text.into()));
3785        }
3786        log::info!("mutating multi-buffer with {:?}", edits);
3787        drop(snapshot);
3788
3789        self.edit(edits, None, cx);
3790    }
3791
3792    pub fn randomly_edit_excerpts(
3793        &mut self,
3794        rng: &mut impl rand::Rng,
3795        mutation_count: usize,
3796        cx: &mut Context<Self>,
3797    ) {
3798        use rand::prelude::*;
3799        use std::env;
3800        use util::RandomCharIter;
3801
3802        let max_excerpts = env::var("MAX_EXCERPTS")
3803            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3804            .unwrap_or(5);
3805
3806        let mut buffers = Vec::new();
3807        for _ in 0..mutation_count {
3808            if rng.random_bool(0.05) {
3809                log::info!("Clearing multi-buffer");
3810                self.clear(cx);
3811                continue;
3812            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3813                let ids = self.excerpt_ids();
3814                let mut excerpts = HashSet::default();
3815                for _ in 0..rng.random_range(0..ids.len()) {
3816                    excerpts.extend(ids.choose(rng).copied());
3817                }
3818
3819                let line_count = rng.random_range(0..5);
3820
3821                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3822
3823                self.expand_excerpts(
3824                    excerpts.iter().cloned(),
3825                    line_count,
3826                    ExpandExcerptDirection::UpAndDown,
3827                    cx,
3828                );
3829                continue;
3830            }
3831
3832            let excerpt_ids = self.excerpt_ids();
3833            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3834                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3835                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3836                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3837                    let buffer = buffers.last().unwrap().read(cx);
3838                    log::info!(
3839                        "Creating new buffer {} with text: {:?}",
3840                        buffer.remote_id(),
3841                        buffer.text()
3842                    );
3843                    buffers.last().unwrap().clone()
3844                } else {
3845                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3846                };
3847
3848                let buffer = buffer_handle.read(cx);
3849                let buffer_text = buffer.text();
3850                let ranges = (0..rng.random_range(0..5))
3851                    .map(|_| {
3852                        let end_ix =
3853                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3854                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3855                        ExcerptRange::new(start_ix..end_ix)
3856                    })
3857                    .collect::<Vec<_>>();
3858                log::info!(
3859                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3860                    buffer_handle.read(cx).remote_id(),
3861                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3862                    ranges
3863                        .iter()
3864                        .map(|r| &buffer_text[r.context.clone()])
3865                        .collect::<Vec<_>>()
3866                );
3867
3868                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3869                log::info!("Inserted with ids: {:?}", excerpt_id);
3870            } else {
3871                let remove_count = rng.random_range(1..=excerpt_ids.len());
3872                let mut excerpts_to_remove = excerpt_ids
3873                    .choose_multiple(rng, remove_count)
3874                    .cloned()
3875                    .collect::<Vec<_>>();
3876                let snapshot = self.snapshot.borrow();
3877                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3878                drop(snapshot);
3879                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3880                self.remove_excerpts(excerpts_to_remove, cx);
3881            }
3882        }
3883    }
3884
3885    pub fn randomly_mutate(
3886        &mut self,
3887        rng: &mut impl rand::Rng,
3888        mutation_count: usize,
3889        cx: &mut Context<Self>,
3890    ) {
3891        use rand::prelude::*;
3892
3893        if rng.random_bool(0.7) || self.singleton {
3894            let buffer = self
3895                .buffers
3896                .values()
3897                .choose(rng)
3898                .map(|state| state.buffer.clone());
3899
3900            if let Some(buffer) = buffer {
3901                buffer.update(cx, |buffer, cx| {
3902                    if rng.random() {
3903                        buffer.randomly_edit(rng, mutation_count, cx);
3904                    } else {
3905                        buffer.randomly_undo_redo(rng, cx);
3906                    }
3907                });
3908            } else {
3909                self.randomly_edit(rng, mutation_count, cx);
3910            }
3911        } else {
3912            self.randomly_edit_excerpts(rng, mutation_count, cx);
3913        }
3914
3915        self.check_invariants(cx);
3916    }
3917
3918    fn check_invariants(&self, cx: &App) {
3919        self.read(cx).check_invariants();
3920    }
3921}
3922
3923impl EventEmitter<Event> for MultiBuffer {}
3924
3925impl MultiBufferSnapshot {
3926    pub fn text(&self) -> String {
3927        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3928            .map(|chunk| chunk.text)
3929            .collect()
3930    }
3931
3932    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3933        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3934            .flat_map(|c| c.chars().rev())
3935    }
3936
3937    fn reversed_chunks_in_range(
3938        &self,
3939        range: Range<MultiBufferOffset>,
3940    ) -> ReversedMultiBufferChunks<'_> {
3941        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3942        cursor.seek(&range.end);
3943        let current_chunks = cursor.region().as_ref().map(|region| {
3944            let start_overshoot = range.start.saturating_sub(region.range.start);
3945            let end_overshoot = range.end - region.range.start;
3946            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3947            let start = region.buffer_range.start + start_overshoot;
3948            region.buffer.reversed_chunks_in_range(start..end)
3949        });
3950        ReversedMultiBufferChunks {
3951            cursor,
3952            current_chunks,
3953            start: range.start,
3954            offset: range.end,
3955        }
3956    }
3957
3958    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3959        let offset = position.to_offset(self);
3960        self.text_for_range(offset..self.len())
3961            .flat_map(|chunk| chunk.chars())
3962    }
3963
3964    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3965        self.chunks(range, false).map(|chunk| chunk.text)
3966    }
3967
3968    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3969        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3970            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3971    }
3972
3973    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3974    where
3975        T: ToOffset,
3976    {
3977        let position = position.to_offset(self);
3978        position == self.clip_offset(position, Bias::Left)
3979            && self
3980                .bytes_in_range(position..self.len())
3981                .flatten()
3982                .copied()
3983                .take(needle.len())
3984                .eq(needle.bytes())
3985    }
3986
3987    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3988        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3989    }
3990
3991    pub fn diff_hunks_in_range<T: ToPoint>(
3992        &self,
3993        range: Range<T>,
3994    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3995        let query_range = range.start.to_point(self)..range.end.to_point(self);
3996        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3997            let diff = self.diffs.get(&buffer.remote_id())?;
3998            let iter = if let Some(main_buffer) = &diff.main_buffer {
3999                let buffer_start = buffer.point_to_offset(buffer_range.start);
4000                let buffer_end = buffer.point_to_offset(buffer_range.end);
4001                itertools::Either::Left(
4002                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4003                        .map(move |hunk| (hunk, buffer, true)),
4004                )
4005            } else {
4006                let buffer_start = buffer.anchor_before(buffer_range.start);
4007                let buffer_end = buffer.anchor_after(buffer_range.end);
4008                itertools::Either::Right(
4009                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4010                        .map(move |hunk| (hunk, buffer, false)),
4011                )
4012            };
4013            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4014                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4015                    return None;
4016                }
4017                let range = if is_inverted {
4018                    hunk.diff_base_byte_range.to_point(&buffer)
4019                } else {
4020                    hunk.range.clone()
4021                };
4022                Some((range, (hunk, is_inverted)))
4023            }))
4024        })
4025        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4026            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4027            {
4028                return None;
4029            }
4030            let end_row = if range.end.column == 0 {
4031                range.end.row
4032            } else {
4033                range.end.row + 1
4034            };
4035
4036            let word_diffs =
4037                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4038                    .then(|| {
4039                        let mut word_diffs = Vec::new();
4040
4041                        if self.show_deleted_hunks || is_inverted {
4042                            let hunk_start_offset = if is_inverted {
4043                                Anchor::in_buffer(
4044                                    excerpt.id,
4045                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4046                                )
4047                                .to_offset(self)
4048                            } else {
4049                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4050                                    .to_offset(self)
4051                            };
4052
4053                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4054                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4055                            }));
4056                        }
4057
4058                        if !is_inverted {
4059                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4060                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4061                            }));
4062                        }
4063                        word_diffs
4064                    })
4065                    .unwrap_or_default();
4066
4067            let buffer_range = if is_inverted {
4068                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4069                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4070            } else {
4071                hunk.buffer_range.clone()
4072            };
4073            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4074                DiffHunkStatusKind::Deleted
4075            } else if hunk.diff_base_byte_range.is_empty() {
4076                DiffHunkStatusKind::Added
4077            } else {
4078                DiffHunkStatusKind::Modified
4079            };
4080            Some(MultiBufferDiffHunk {
4081                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4082                buffer_id: excerpt.buffer_id,
4083                excerpt_id: excerpt.id,
4084                buffer_range,
4085                word_diffs,
4086                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4087                    ..BufferOffset(hunk.diff_base_byte_range.end),
4088                status: DiffHunkStatus {
4089                    kind: status_kind,
4090                    secondary: hunk.secondary_status,
4091                },
4092            })
4093        })
4094    }
4095
4096    fn excerpts_for_range<T: ToOffset>(
4097        &self,
4098        range: Range<T>,
4099    ) -> impl Iterator<Item = &Excerpt> + '_ {
4100        let range = range.start.to_offset(self)..range.end.to_offset(self);
4101        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4102        cursor.seek(&range.start);
4103        std::iter::from_fn(move || {
4104            let region = cursor.region()?;
4105            if region.range.start > range.end
4106                || region.range.start == range.end && region.range.start > range.start
4107            {
4108                return None;
4109            }
4110            let excerpt = region.excerpt;
4111            cursor.next_excerpt_forwards();
4112            Some(excerpt)
4113        })
4114    }
4115
4116    pub fn excerpt_ids_for_range<T: ToOffset>(
4117        &self,
4118        range: Range<T>,
4119    ) -> impl Iterator<Item = ExcerptId> + '_ {
4120        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4121    }
4122
4123    pub fn buffer_ids_for_range<T: ToOffset>(
4124        &self,
4125        range: Range<T>,
4126    ) -> impl Iterator<Item = BufferId> + '_ {
4127        self.excerpts_for_range(range)
4128            .map(|excerpt| excerpt.buffer_id)
4129    }
4130
4131    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4132    ///
4133    /// The passed in anchors must be ordered.
4134    pub fn text_anchors_to_visible_anchors(
4135        &self,
4136        anchors: impl IntoIterator<Item = text::Anchor>,
4137    ) -> Vec<Option<Anchor>> {
4138        let anchors = anchors.into_iter();
4139        let mut result = Vec::with_capacity(anchors.size_hint().0);
4140        let mut anchors = anchors.peekable();
4141        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4142        'anchors: while let Some(anchor) = anchors.peek() {
4143            let Some(buffer_id) = anchor.buffer_id else {
4144                anchors.next();
4145                result.push(None);
4146                continue 'anchors;
4147            };
4148            let mut same_buffer_anchors =
4149                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4150
4151            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4152                let Some(mut next) = same_buffer_anchors.next() else {
4153                    continue 'anchors;
4154                };
4155                'excerpts: for locator in locators.iter() {
4156                    if cursor.seek_forward(&Some(locator), Bias::Left)
4157                        && let Some(excerpt) = cursor.item()
4158                    {
4159                        loop {
4160                            // anchor is before the first excerpt
4161                            if excerpt
4162                                .range
4163                                .context
4164                                .start
4165                                .cmp(&next, &excerpt.buffer)
4166                                .is_gt()
4167                            {
4168                                // so we skip it and try the next anchor
4169                                result.push(None);
4170                                match same_buffer_anchors.next() {
4171                                    Some(anchor) => next = anchor,
4172                                    None => continue 'anchors,
4173                                }
4174                            // anchor is within the excerpt
4175                            } else if excerpt
4176                                .range
4177                                .context
4178                                .end
4179                                .cmp(&next, &excerpt.buffer)
4180                                .is_ge()
4181                            {
4182                                // record it and all following anchors that are within
4183                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4184                                result.extend(
4185                                    same_buffer_anchors
4186                                        .peeking_take_while(|a| {
4187                                            excerpt
4188                                                .range
4189                                                .context
4190                                                .end
4191                                                .cmp(a, &excerpt.buffer)
4192                                                .is_ge()
4193                                        })
4194                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4195                                );
4196                                match same_buffer_anchors.next() {
4197                                    Some(anchor) => next = anchor,
4198                                    None => continue 'anchors,
4199                                }
4200                            // anchor is after the excerpt, try the next one
4201                            } else {
4202                                continue 'excerpts;
4203                            }
4204                        }
4205                    }
4206                }
4207                // account for `next`
4208                result.push(None);
4209            }
4210            result.extend(same_buffer_anchors.map(|_| None));
4211        }
4212
4213        result
4214    }
4215
4216    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4217        &self,
4218        ranges: impl Iterator<Item = Range<T>>,
4219    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4220        ranges.flat_map(|range| {
4221            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4222                .into_iter()
4223        })
4224    }
4225
4226    pub fn range_to_buffer_ranges<R, T>(
4227        &self,
4228        range: R,
4229    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4230    where
4231        R: RangeBounds<T>,
4232        T: ToOffset,
4233    {
4234        self.range_to_buffer_ranges_with_context(range)
4235            .into_iter()
4236            .map(|(buffer, range, id, _context)| (buffer, range, id))
4237            .collect()
4238    }
4239
4240    pub fn range_to_buffer_ranges_with_context<R, T>(
4241        &self,
4242        range: R,
4243    ) -> Vec<(
4244        &BufferSnapshot,
4245        Range<BufferOffset>,
4246        ExcerptId,
4247        Range<text::Anchor>,
4248    )>
4249    where
4250        R: RangeBounds<T>,
4251        T: ToOffset,
4252    {
4253        let start = match range.start_bound() {
4254            Bound::Included(start) => start.to_offset(self),
4255            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4256            Bound::Unbounded => MultiBufferOffset::ZERO,
4257        };
4258        let end_bound = match range.end_bound() {
4259            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4260            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4261            Bound::Unbounded => Bound::Unbounded,
4262        };
4263        let bounds = (Bound::Included(start), end_bound);
4264
4265        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4266        cursor.seek(&start);
4267
4268        let mut result: Vec<(
4269            &BufferSnapshot,
4270            Range<BufferOffset>,
4271            ExcerptId,
4272            Range<text::Anchor>,
4273        )> = Vec::new();
4274        while let Some(region) = cursor.region() {
4275            let dominated_by_end_bound = match end_bound {
4276                Bound::Included(end) => region.range.start > end,
4277                Bound::Excluded(end) => region.range.start >= end,
4278                Bound::Unbounded => false,
4279            };
4280            if dominated_by_end_bound {
4281                break;
4282            }
4283            if region.is_main_buffer {
4284                let start_overshoot = start.saturating_sub(region.range.start);
4285                let end_offset = match end_bound {
4286                    Bound::Included(end) | Bound::Excluded(end) => end,
4287                    Bound::Unbounded => region.range.end,
4288                };
4289                let end_overshoot = end_offset.saturating_sub(region.range.start);
4290                let start = region
4291                    .buffer_range
4292                    .end
4293                    .min(region.buffer_range.start + start_overshoot);
4294                let end = region
4295                    .buffer_range
4296                    .end
4297                    .min(region.buffer_range.start + end_overshoot);
4298                let context = region.excerpt.range.context.clone();
4299                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4300                    *excerpt_id == region.excerpt.id && prev_range.end == start
4301                }) {
4302                    prev.1.end = end;
4303                } else {
4304                    result.push((region.buffer, start..end, region.excerpt.id, context));
4305                }
4306            }
4307            cursor.next();
4308        }
4309
4310        if let Some(excerpt) = cursor.excerpt() {
4311            let dominated_by_prev_excerpt =
4312                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4313            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4314                let excerpt_position = self.len();
4315                if bounds.contains(&excerpt_position) {
4316                    let buffer_offset =
4317                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4318                    let context = excerpt.range.context.clone();
4319                    result.push((
4320                        &excerpt.buffer,
4321                        buffer_offset..buffer_offset,
4322                        excerpt.id,
4323                        context,
4324                    ));
4325                }
4326            }
4327        }
4328
4329        result
4330    }
4331
4332    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4333        &self,
4334        range: Range<T>,
4335    ) -> impl Iterator<
4336        Item = (
4337            &BufferSnapshot,
4338            Range<BufferOffset>,
4339            ExcerptId,
4340            Option<Anchor>,
4341        ),
4342    > + '_ {
4343        let start = range.start.to_offset(self);
4344        let end = range.end.to_offset(self);
4345
4346        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4347        cursor.seek(&start);
4348
4349        std::iter::from_fn(move || {
4350            let region = cursor.region()?;
4351            if region.range.start > end {
4352                return None;
4353            }
4354            let start_overshoot = start.saturating_sub(region.range.start);
4355            let end_overshoot = end.saturating_sub(region.range.start);
4356            let start = region
4357                .buffer_range
4358                .end
4359                .min(region.buffer_range.start + start_overshoot);
4360            let end = region
4361                .buffer_range
4362                .end
4363                .min(region.buffer_range.start + end_overshoot);
4364
4365            let region_excerpt_id = region.excerpt.id;
4366            let deleted_hunk_anchor = if region.is_main_buffer {
4367                None
4368            } else {
4369                Some(self.anchor_before(region.range.start))
4370            };
4371            let result = (
4372                region.buffer,
4373                start..end,
4374                region_excerpt_id,
4375                deleted_hunk_anchor,
4376            );
4377            cursor.next();
4378            Some(result)
4379        })
4380    }
4381
4382    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4383    /// coordinates.
4384    ///
4385    /// The given callback will be called for every excerpt intersecting the given range. It will
4386    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4387    /// The callback should return an iterator of metadata items from that buffer, each paired
4388    /// with a buffer range.
4389    ///
4390    /// The returned iterator yields each of these metadata items, paired with its range in
4391    /// multi-buffer coordinates.
4392    fn lift_buffer_metadata<'a, MBD, M, I>(
4393        &'a self,
4394        query_range: Range<MBD>,
4395        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4396    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4397    where
4398        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4399        MBD: MultiBufferDimension
4400            + Ord
4401            + Sub<Output = MBD::TextDimension>
4402            + ops::Add<MBD::TextDimension, Output = MBD>
4403            + ops::AddAssign<MBD::TextDimension>,
4404        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4405            + ops::Add<Output = MBD::TextDimension>
4406            + AddAssign<MBD::TextDimension>
4407            + Ord,
4408    {
4409        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4410        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4411
4412        // Find the excerpt and buffer offset where the given range ends.
4413        cursor.seek(&query_range.end);
4414        let mut range_end = None;
4415        while let Some(region) = cursor.region() {
4416            if region.is_main_buffer {
4417                let mut buffer_end = region.buffer_range.start;
4418                let overshoot = if query_range.end > region.range.start {
4419                    query_range.end - region.range.start
4420                } else {
4421                    <MBD::TextDimension>::default()
4422                };
4423                buffer_end = buffer_end + overshoot;
4424                range_end = Some((region.excerpt.id, buffer_end));
4425                break;
4426            }
4427            cursor.next();
4428        }
4429
4430        cursor.seek(&query_range.start);
4431
4432        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4433            && region.range.start > MBD::default()
4434        {
4435            cursor.prev()
4436        } else if let Some(region) = cursor.region()
4437            && region.is_main_buffer
4438            && region.diff_hunk_status.is_some()
4439        {
4440            cursor.prev();
4441            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4442                cursor.next();
4443            }
4444        }
4445
4446        iter::from_fn(move || {
4447            loop {
4448                let excerpt = cursor.excerpt()?;
4449
4450                // If we have already retrieved metadata for this excerpt, continue to use it.
4451                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4452                    .as_mut()
4453                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4454                {
4455                    Some(metadata)
4456                }
4457                // Otherwise, compute the intersection of the input range with the excerpt's range,
4458                // and retrieve the metadata for the resulting range.
4459                else {
4460                    let region = cursor.region()?;
4461                    let mut buffer_start;
4462                    if region.is_main_buffer {
4463                        buffer_start = region.buffer_range.start;
4464                        if query_range.start > region.range.start {
4465                            let overshoot = query_range.start - region.range.start;
4466                            buffer_start = buffer_start + overshoot;
4467                        }
4468                        buffer_start = buffer_start.min(region.buffer_range.end);
4469                    } else {
4470                        buffer_start = cursor.main_buffer_position()?;
4471                    };
4472                    let mut buffer_end = excerpt
4473                        .range
4474                        .context
4475                        .end
4476                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4477                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4478                        && excerpt.id == end_excerpt_id
4479                    {
4480                        buffer_end = buffer_end.min(end_buffer_offset);
4481                    }
4482
4483                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4484                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4485                    })
4486                };
4487
4488                // Visit each metadata item.
4489                if let Some((metadata_buffer_range, metadata)) =
4490                    metadata_iter.and_then(Iterator::next)
4491                {
4492                    // Find the multibuffer regions that contain the start and end of
4493                    // the metadata item's range.
4494                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4495                        while let Some(region) = cursor.region() {
4496                            if (region.is_main_buffer
4497                                && (region.buffer_range.end >= metadata_buffer_range.start
4498                                    || cursor.is_at_end_of_excerpt()))
4499                                || (!region.is_main_buffer
4500                                    && region.buffer_range.start == metadata_buffer_range.start)
4501                            {
4502                                break;
4503                            }
4504                            cursor.next();
4505                        }
4506                    }
4507                    let start_region = cursor.region()?.clone();
4508                    while let Some(region) = cursor.region() {
4509                        if region.is_main_buffer
4510                            && (region.buffer_range.end > metadata_buffer_range.end
4511                                || cursor.is_at_end_of_excerpt())
4512                        {
4513                            break;
4514                        }
4515                        cursor.next();
4516                    }
4517                    let end_region = cursor.region();
4518
4519                    // Convert the metadata item's range into multibuffer coordinates.
4520                    let mut start_position = start_region.range.start;
4521                    let region_buffer_start = start_region.buffer_range.start;
4522                    if start_region.is_main_buffer
4523                        && metadata_buffer_range.start > region_buffer_start
4524                    {
4525                        start_position =
4526                            start_position + (metadata_buffer_range.start - region_buffer_start);
4527                        start_position = start_position.min(start_region.range.end);
4528                    }
4529
4530                    let mut end_position = self.max_position();
4531                    if let Some(end_region) = &end_region {
4532                        end_position = end_region.range.start;
4533                        debug_assert!(end_region.is_main_buffer);
4534                        let region_buffer_start = end_region.buffer_range.start;
4535                        if metadata_buffer_range.end > region_buffer_start {
4536                            end_position =
4537                                end_position + (metadata_buffer_range.end - region_buffer_start);
4538                        }
4539                        end_position = end_position.min(end_region.range.end);
4540                    }
4541
4542                    if start_position <= query_range.end && end_position >= query_range.start {
4543                        return Some((start_position..end_position, metadata, excerpt));
4544                    }
4545                }
4546                // When there are no more metadata items for this excerpt, move to the next excerpt.
4547                else {
4548                    current_excerpt_metadata.take();
4549                    if let Some((end_excerpt_id, _)) = range_end
4550                        && excerpt.id == end_excerpt_id
4551                    {
4552                        return None;
4553                    }
4554                    cursor.next_excerpt_forwards();
4555                }
4556            }
4557        })
4558    }
4559
4560    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4561        let offset = position.to_offset(self);
4562
4563        let mut cursor = self
4564            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4565            );
4566        cursor.seek(&DimensionPair {
4567            key: offset,
4568            value: None,
4569        });
4570        cursor.seek_to_start_of_current_excerpt();
4571        let excerpt = cursor.excerpt()?;
4572
4573        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4574        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4575        let current_position = self
4576            .anchor_before(offset)
4577            .text_anchor
4578            .to_offset(&excerpt.buffer);
4579
4580        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4581            if let Some(main_buffer) = &diff.main_buffer {
4582                for hunk in diff
4583                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4584                {
4585                    if hunk.diff_base_byte_range.end >= current_position {
4586                        continue;
4587                    }
4588                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4589                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4590                    return Some(MultiBufferRow(start.row));
4591                }
4592            } else {
4593                let excerpt_end = excerpt
4594                    .buffer
4595                    .anchor_before(excerpt_end.min(current_position));
4596                for hunk in diff.hunks_intersecting_range_rev(
4597                    excerpt.range.context.start..excerpt_end,
4598                    &excerpt.buffer,
4599                ) {
4600                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4601                    if hunk_end >= current_position {
4602                        continue;
4603                    }
4604                    let start =
4605                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4606                    return Some(MultiBufferRow(start.row));
4607                }
4608            }
4609        }
4610
4611        loop {
4612            cursor.prev_excerpt();
4613            let excerpt = cursor.excerpt()?;
4614
4615            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4616                continue;
4617            };
4618            if let Some(main_buffer) = &diff.main_buffer {
4619                let Some(hunk) = diff
4620                    .hunks_intersecting_base_text_range_rev(
4621                        excerpt.range.context.to_offset(&excerpt.buffer),
4622                        main_buffer,
4623                    )
4624                    .next()
4625                else {
4626                    continue;
4627                };
4628                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4629                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4630                return Some(MultiBufferRow(start.row));
4631            } else {
4632                let Some(hunk) = diff
4633                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4634                    .next()
4635                else {
4636                    continue;
4637                };
4638                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4639                return Some(MultiBufferRow(start.row));
4640            }
4641        }
4642    }
4643
4644    pub fn has_diff_hunks(&self) -> bool {
4645        self.diffs.values().any(|diff| !diff.is_empty())
4646    }
4647
4648    pub fn is_inside_word<T: ToOffset>(
4649        &self,
4650        position: T,
4651        scope_context: Option<CharScopeContext>,
4652    ) -> bool {
4653        let position = position.to_offset(self);
4654        let classifier = self
4655            .char_classifier_at(position)
4656            .scope_context(scope_context);
4657        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4658        let prev_char_kind = self
4659            .reversed_chars_at(position)
4660            .next()
4661            .map(|c| classifier.kind(c));
4662        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4663    }
4664
4665    pub fn surrounding_word<T: ToOffset>(
4666        &self,
4667        start: T,
4668        scope_context: Option<CharScopeContext>,
4669    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4670        let mut start = start.to_offset(self);
4671        let mut end = start;
4672        let mut next_chars = self.chars_at(start).peekable();
4673        let mut prev_chars = self.reversed_chars_at(start).peekable();
4674
4675        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4676
4677        let word_kind = cmp::max(
4678            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4679            next_chars.peek().copied().map(|c| classifier.kind(c)),
4680        );
4681
4682        for ch in prev_chars {
4683            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4684                start -= ch.len_utf8();
4685            } else {
4686                break;
4687            }
4688        }
4689
4690        for ch in next_chars {
4691            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4692                end += ch.len_utf8();
4693            } else {
4694                break;
4695            }
4696        }
4697
4698        (start..end, word_kind)
4699    }
4700
4701    pub fn char_kind_before<T: ToOffset>(
4702        &self,
4703        start: T,
4704        scope_context: Option<CharScopeContext>,
4705    ) -> Option<CharKind> {
4706        let start = start.to_offset(self);
4707        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4708        self.reversed_chars_at(start)
4709            .next()
4710            .map(|ch| classifier.kind(ch))
4711    }
4712
4713    pub fn is_singleton(&self) -> bool {
4714        self.singleton
4715    }
4716
4717    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4718        if self.singleton {
4719            self.excerpts
4720                .iter()
4721                .next()
4722                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4723        } else {
4724            None
4725        }
4726    }
4727
4728    pub fn len(&self) -> MultiBufferOffset {
4729        self.diff_transforms.summary().output.len
4730    }
4731
4732    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4733        MBD::from_summary(&self.text_summary())
4734    }
4735
4736    pub fn is_empty(&self) -> bool {
4737        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4738    }
4739
4740    pub fn widest_line_number(&self) -> u32 {
4741        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4742        self.excerpts.summary().widest_line_number + 1
4743    }
4744
4745    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4746        let range = range.start.to_offset(self)..range.end.to_offset(self);
4747        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4748        excerpts.seek(&range.start);
4749
4750        let mut chunk;
4751        let mut has_trailing_newline;
4752        let excerpt_bytes;
4753        if let Some(region) = excerpts.region() {
4754            let mut bytes = region.buffer.bytes_in_range(
4755                region.buffer_range.start + (range.start - region.range.start)
4756                    ..(region.buffer_range.start + (range.end - region.range.start))
4757                        .min(region.buffer_range.end),
4758            );
4759            chunk = bytes.next().unwrap_or(&[][..]);
4760            excerpt_bytes = Some(bytes);
4761            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4762            if chunk.is_empty() && has_trailing_newline {
4763                chunk = b"\n";
4764                has_trailing_newline = false;
4765            }
4766        } else {
4767            chunk = &[][..];
4768            excerpt_bytes = None;
4769            has_trailing_newline = false;
4770        };
4771
4772        MultiBufferBytes {
4773            range,
4774            cursor: excerpts,
4775            excerpt_bytes,
4776            has_trailing_newline,
4777            chunk,
4778        }
4779    }
4780
4781    pub fn reversed_bytes_in_range<T: ToOffset>(
4782        &self,
4783        range: Range<T>,
4784    ) -> ReversedMultiBufferBytes<'_> {
4785        let range = range.start.to_offset(self)..range.end.to_offset(self);
4786        let mut chunks = self.reversed_chunks_in_range(range.clone());
4787        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4788        ReversedMultiBufferBytes {
4789            range,
4790            chunks,
4791            chunk,
4792        }
4793    }
4794
4795    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4796        let mut cursor = self.cursor::<Point, Point>();
4797        cursor.seek(&Point::new(start_row.0, 0));
4798        let mut result = MultiBufferRows {
4799            point: Point::new(0, 0),
4800            is_empty: self.excerpts.is_empty(),
4801            is_singleton: self.is_singleton(),
4802            cursor,
4803        };
4804        result.seek(start_row);
4805        result
4806    }
4807
4808    pub fn chunks<T: ToOffset>(
4809        &self,
4810        range: Range<T>,
4811        language_aware: bool,
4812    ) -> MultiBufferChunks<'_> {
4813        let mut chunks = MultiBufferChunks {
4814            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4815                ..ExcerptDimension(MultiBufferOffset::ZERO),
4816            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4817            excerpts: self.excerpts.cursor(()),
4818            diff_transforms: self.diff_transforms.cursor(()),
4819            diffs: &self.diffs,
4820            diff_base_chunks: None,
4821            excerpt_chunks: None,
4822            buffer_chunk: None,
4823            language_aware,
4824        };
4825        let range = range.start.to_offset(self)..range.end.to_offset(self);
4826        chunks.seek(range);
4827        chunks
4828    }
4829
4830    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4831        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4832    }
4833
4834    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4835        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4836    }
4837
4838    pub fn clip_offset_utf16(
4839        &self,
4840        offset: MultiBufferOffsetUtf16,
4841        bias: Bias,
4842    ) -> MultiBufferOffsetUtf16 {
4843        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4844    }
4845
4846    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4847        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4848            buffer.clip_point_utf16(Unclipped(point), bias)
4849        })
4850    }
4851
4852    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4853        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4854    }
4855
4856    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4857        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4858    }
4859
4860    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4861        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4862    }
4863
4864    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4865        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4866    }
4867
4868    #[instrument(skip_all)]
4869    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4870        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4871    }
4872
4873    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4874        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4875    }
4876
4877    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4878        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4879    }
4880
4881    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4882        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4883    }
4884
4885    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4886        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4887    }
4888
4889    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4890        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4891    }
4892
4893    fn clip_dimension<MBD, BD>(
4894        &self,
4895        position: MBD,
4896        bias: Bias,
4897        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4898    ) -> MBD
4899    where
4900        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4901        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4902    {
4903        let mut cursor = self.cursor::<MBD, BD>();
4904        cursor.seek(&position);
4905        if let Some(region) = cursor.region() {
4906            if position >= region.range.end {
4907                return region.range.end;
4908            }
4909            let overshoot = position - region.range.start;
4910            let mut buffer_position = region.buffer_range.start;
4911            buffer_position += overshoot;
4912            let clipped_buffer_position =
4913                clip_buffer_position(region.buffer, buffer_position, bias);
4914            let mut position = region.range.start;
4915            position += clipped_buffer_position - region.buffer_range.start;
4916            position
4917        } else {
4918            self.max_position()
4919        }
4920    }
4921
4922    #[instrument(skip_all)]
4923    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4924        &self,
4925        key: MBR1,
4926        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4927    ) -> MBR2
4928    where
4929        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4930        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4931        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4932        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4933    {
4934        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4935        cursor.seek(&DimensionPair { key, value: None });
4936        if let Some(region) = cursor.region() {
4937            if key >= region.range.end.key {
4938                return region.range.end.value.unwrap();
4939            }
4940            let start_key = region.range.start.key;
4941            let start_value = region.range.start.value.unwrap();
4942            let buffer_start_key = region.buffer_range.start.key;
4943            let buffer_start_value = region.buffer_range.start.value.unwrap();
4944            let mut buffer_key = buffer_start_key;
4945            buffer_key += key - start_key;
4946            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4947            let mut result = start_value;
4948            result += buffer_value - buffer_start_value;
4949            result
4950        } else {
4951            self.max_position()
4952        }
4953    }
4954
4955    pub fn point_to_buffer_offset<T: ToOffset>(
4956        &self,
4957        point: T,
4958    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4959        let offset = point.to_offset(self);
4960        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4961        cursor.seek(&offset);
4962        let region = cursor.region()?;
4963        let overshoot = offset - region.range.start;
4964        let buffer_offset = region.buffer_range.start + overshoot;
4965        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4966            && region.has_trailing_newline
4967            && !region.is_main_buffer
4968        {
4969            let main_buffer_position = cursor.main_buffer_position()?;
4970            let buffer_snapshot = &cursor.excerpt()?.buffer;
4971            return Some((buffer_snapshot, main_buffer_position));
4972        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4973            return None;
4974        }
4975        Some((region.buffer, buffer_offset))
4976    }
4977
4978    pub fn point_to_buffer_point(
4979        &self,
4980        point: Point,
4981    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4982        let mut cursor = self.cursor::<Point, Point>();
4983        cursor.seek(&point);
4984        let region = cursor.region()?;
4985        let overshoot = point - region.range.start;
4986        let buffer_point = region.buffer_range.start + overshoot;
4987        let excerpt = cursor.excerpt()?;
4988        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4989            && region.has_trailing_newline
4990            && !region.is_main_buffer
4991        {
4992            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4993        } else if buffer_point > region.buffer.max_point() {
4994            return None;
4995        }
4996        Some((region.buffer, buffer_point, excerpt.id))
4997    }
4998
4999    pub fn suggested_indents(
5000        &self,
5001        rows: impl IntoIterator<Item = u32>,
5002        cx: &App,
5003    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5004        let mut result = BTreeMap::new();
5005        self.suggested_indents_callback(
5006            rows,
5007            &mut |row, indent| {
5008                result.insert(row, indent);
5009                ControlFlow::Continue(())
5010            },
5011            cx,
5012        );
5013        result
5014    }
5015
5016    // move this to be a generator once those are a thing
5017    pub fn suggested_indents_callback(
5018        &self,
5019        rows: impl IntoIterator<Item = u32>,
5020        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5021        cx: &App,
5022    ) {
5023        let mut rows_for_excerpt = Vec::new();
5024        let mut cursor = self.cursor::<Point, Point>();
5025        let mut rows = rows.into_iter().peekable();
5026        let mut prev_row = u32::MAX;
5027        let mut prev_language_indent_size = IndentSize::default();
5028
5029        while let Some(row) = rows.next() {
5030            cursor.seek(&Point::new(row, 0));
5031            let Some(region) = cursor.region() else {
5032                continue;
5033            };
5034
5035            // Retrieve the language and indent size once for each disjoint region being indented.
5036            let single_indent_size = if row.saturating_sub(1) == prev_row {
5037                prev_language_indent_size
5038            } else {
5039                region
5040                    .buffer
5041                    .language_indent_size_at(Point::new(row, 0), cx)
5042            };
5043            prev_language_indent_size = single_indent_size;
5044            prev_row = row;
5045
5046            let start_buffer_row = region.buffer_range.start.row;
5047            let start_multibuffer_row = region.range.start.row;
5048            let end_multibuffer_row = region.range.end.row;
5049
5050            rows_for_excerpt.push(row);
5051            while let Some(next_row) = rows.peek().copied() {
5052                if end_multibuffer_row > next_row {
5053                    rows_for_excerpt.push(next_row);
5054                    rows.next();
5055                } else {
5056                    break;
5057                }
5058            }
5059
5060            let buffer_rows = rows_for_excerpt
5061                .drain(..)
5062                .map(|row| start_buffer_row + row - start_multibuffer_row);
5063            let buffer_indents = region
5064                .buffer
5065                .suggested_indents(buffer_rows, single_indent_size);
5066            for (row, indent) in buffer_indents {
5067                if cb(
5068                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5069                    indent,
5070                )
5071                .is_break()
5072                {
5073                    return;
5074                }
5075            }
5076        }
5077    }
5078
5079    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5080        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5081            let mut size = buffer.indent_size_for_line(range.start.row);
5082            size.len = size
5083                .len
5084                .min(range.end.column)
5085                .saturating_sub(range.start.column);
5086            size
5087        } else {
5088            IndentSize::spaces(0)
5089        }
5090    }
5091
5092    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5093        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5094            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5095        } else {
5096            LineIndent::spaces(0)
5097        }
5098    }
5099
5100    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5101        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5102
5103        if self.language_settings(cx).extend_comment_on_newline
5104            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5105        {
5106            let delimiters = language_scope.line_comment_prefixes();
5107            for delimiter in delimiters {
5108                if *self
5109                    .chars_at(Point::new(row.0, indent.len() as u32))
5110                    .take(delimiter.chars().count())
5111                    .collect::<String>()
5112                    .as_str()
5113                    == **delimiter
5114                {
5115                    indent.push_str(delimiter);
5116                    break;
5117                }
5118            }
5119        }
5120
5121        indent
5122    }
5123
5124    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5125    where
5126        T: ToOffset,
5127    {
5128        for char in self.reversed_chars_at(position) {
5129            if !char.is_whitespace() {
5130                return false;
5131            }
5132            if char == '\n' {
5133                return true;
5134            }
5135        }
5136        true
5137    }
5138
5139    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5140        while row.0 > 0 {
5141            row.0 -= 1;
5142            if !self.is_line_blank(row) {
5143                return Some(row);
5144            }
5145        }
5146        None
5147    }
5148
5149    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5150        if let Some((_, range)) = self.buffer_line_for_row(row) {
5151            range.end.column - range.start.column
5152        } else {
5153            0
5154        }
5155    }
5156
5157    pub fn buffer_line_for_row(
5158        &self,
5159        row: MultiBufferRow,
5160    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5161        let mut cursor = self.cursor::<Point, Point>();
5162        let point = Point::new(row.0, 0);
5163        cursor.seek(&point);
5164        let region = cursor.region()?;
5165        let overshoot = point.min(region.range.end) - region.range.start;
5166        let buffer_point = region.buffer_range.start + overshoot;
5167        if buffer_point.row > region.buffer_range.end.row {
5168            return None;
5169        }
5170        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5171        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5172            .min(region.buffer_range.end);
5173        Some((region.buffer, line_start..line_end))
5174    }
5175
5176    pub fn max_point(&self) -> Point {
5177        self.text_summary().lines
5178    }
5179
5180    pub fn max_row(&self) -> MultiBufferRow {
5181        MultiBufferRow(self.text_summary().lines.row)
5182    }
5183
5184    pub fn text_summary(&self) -> MBTextSummary {
5185        self.diff_transforms.summary().output
5186    }
5187
5188    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5189    where
5190        MBD: MultiBufferDimension + AddAssign,
5191        O: ToOffset,
5192    {
5193        let range = range.start.to_offset(self)..range.end.to_offset(self);
5194        let mut cursor = self
5195            .diff_transforms
5196            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5197        cursor.seek(&range.start, Bias::Right);
5198
5199        let Some(first_transform) = cursor.item() else {
5200            return MBD::from_summary(&MBTextSummary::default());
5201        };
5202
5203        let diff_transform_start = cursor.start().0;
5204        let diff_transform_end = cursor.end().0;
5205        let diff_start = range.start;
5206        let start_overshoot = diff_start - diff_transform_start;
5207        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5208
5209        let mut result = match first_transform {
5210            DiffTransform::BufferContent { .. } => {
5211                let excerpt_start = cursor.start().1 + start_overshoot;
5212                let excerpt_end = cursor.start().1 + end_overshoot;
5213                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5214            }
5215            DiffTransform::DeletedHunk {
5216                buffer_id,
5217                base_text_byte_range,
5218                has_trailing_newline,
5219                ..
5220            } => {
5221                let buffer_start = base_text_byte_range.start + start_overshoot;
5222                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5223                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5224                    panic!("{:?} is in non-existent deleted hunk", range.start)
5225                };
5226
5227                let include_trailing_newline =
5228                    *has_trailing_newline && range.end >= diff_transform_end;
5229                if include_trailing_newline {
5230                    buffer_end -= 1;
5231                }
5232
5233                let mut summary = base_text
5234                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5235
5236                if include_trailing_newline {
5237                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5238                        &TextSummary::newline(),
5239                    ))
5240                }
5241
5242                let mut result = MBD::default();
5243                result.add_text_dim(&summary);
5244                result
5245            }
5246        };
5247        if range.end < diff_transform_end {
5248            return result;
5249        }
5250
5251        cursor.next();
5252        result.add_mb_text_summary(
5253            &cursor
5254                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5255                .0,
5256        );
5257
5258        let Some(last_transform) = cursor.item() else {
5259            return result;
5260        };
5261
5262        let overshoot = range.end - cursor.start().0;
5263        let suffix = match last_transform {
5264            DiffTransform::BufferContent { .. } => {
5265                let end = cursor.start().1 + overshoot;
5266                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5267            }
5268            DiffTransform::DeletedHunk {
5269                base_text_byte_range,
5270                buffer_id,
5271                has_trailing_newline,
5272                ..
5273            } => {
5274                let buffer_end = base_text_byte_range.start + overshoot;
5275                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5276                    panic!("{:?} is in non-existent deleted hunk", range.end)
5277                };
5278
5279                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5280                    base_text_byte_range.start..buffer_end,
5281                );
5282                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5283                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5284                        &TextSummary::from("\n"),
5285                    ))
5286                }
5287
5288                let mut result = MBD::default();
5289                result.add_text_dim(&suffix);
5290                result
5291            }
5292        };
5293
5294        result += suffix;
5295        result
5296    }
5297
5298    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5299    where
5300        MBD: MultiBufferDimension + AddAssign,
5301    {
5302        let mut summary = MBD::default();
5303        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5304        cursor.seek(&range.start, Bias::Right);
5305        if let Some(excerpt) = cursor.item() {
5306            let mut end_before_newline = cursor.end();
5307            if excerpt.has_trailing_newline {
5308                end_before_newline -= 1;
5309            }
5310
5311            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5312            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5313            let end_in_excerpt =
5314                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5315            summary.add_text_dim(
5316                &excerpt
5317                    .buffer
5318                    .text_summary_for_range::<MBD::TextDimension, _>(
5319                        start_in_excerpt..end_in_excerpt,
5320                    ),
5321            );
5322
5323            if range.end > end_before_newline {
5324                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5325            }
5326
5327            cursor.next();
5328        }
5329
5330        if range.end > *cursor.start() {
5331            summary += cursor
5332                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5333                .0;
5334            if let Some(excerpt) = cursor.item() {
5335                range.end = cmp::max(*cursor.start(), range.end);
5336
5337                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5338                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5339                summary.add_text_dim(
5340                    &excerpt
5341                        .buffer
5342                        .text_summary_for_range::<MBD::TextDimension, _>(
5343                            excerpt_start..end_in_excerpt,
5344                        ),
5345                );
5346            }
5347        }
5348
5349        summary
5350    }
5351
5352    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5353    where
5354        MBD: MultiBufferDimension
5355            + Ord
5356            + Sub<Output = MBD::TextDimension>
5357            + Sub<MBD::TextDimension, Output = MBD>
5358            + AddAssign<MBD::TextDimension>
5359            + Add<MBD::TextDimension, Output = MBD>,
5360        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5361    {
5362        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5363        let locator = self.excerpt_locator_for_id(excerpt_id);
5364        let (start, _, mut item) = self
5365            .excerpts
5366            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5367        let mut start = MBD::from_summary(&start.text);
5368        if item.is_none() && excerpt_id == ExcerptId::max() {
5369            item = self.excerpts.last();
5370            if let Some(last_summary) = self.excerpts.last_summary() {
5371                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5372            }
5373        }
5374
5375        if self.diff_transforms.is_empty() {
5376            let excerpt_start_position = ExcerptDimension(start);
5377            if let Some(excerpt) = item {
5378                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5379                    return excerpt_start_position.0;
5380                }
5381                let excerpt_buffer_start = excerpt
5382                    .range
5383                    .context
5384                    .start
5385                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5386                let excerpt_buffer_end = excerpt
5387                    .range
5388                    .context
5389                    .end
5390                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5391                let buffer_summary = anchor
5392                    .text_anchor
5393                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5394                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5395                let mut position = excerpt_start_position;
5396                if summary > excerpt_buffer_start {
5397                    position += summary - excerpt_buffer_start;
5398                }
5399
5400                position.0
5401            } else {
5402                excerpt_start_position.0
5403            }
5404        } else {
5405            let mut diff_transforms_cursor = self
5406                .diff_transforms
5407                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5408            diff_transforms_cursor.next();
5409
5410            let excerpt_start_position = ExcerptDimension(start);
5411            if let Some(excerpt) = item {
5412                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5413                    return self.resolve_summary_for_anchor(
5414                        &Anchor::min(),
5415                        excerpt_start_position,
5416                        &mut diff_transforms_cursor,
5417                    );
5418                }
5419                let excerpt_buffer_start = excerpt
5420                    .range
5421                    .context
5422                    .start
5423                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5424                let excerpt_buffer_end = excerpt
5425                    .range
5426                    .context
5427                    .end
5428                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5429                let buffer_summary = anchor
5430                    .text_anchor
5431                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5432                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5433                let mut position = excerpt_start_position;
5434                if summary > excerpt_buffer_start {
5435                    position += summary - excerpt_buffer_start;
5436                }
5437
5438                if diff_transforms_cursor.start().0 < position {
5439                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5440                }
5441                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5442            } else {
5443                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5444                self.resolve_summary_for_anchor(
5445                    &Anchor::max(),
5446                    excerpt_start_position,
5447                    &mut diff_transforms_cursor,
5448                )
5449            }
5450        }
5451    }
5452
5453    fn resolve_summary_for_anchor<MBD>(
5454        &self,
5455        anchor: &Anchor,
5456        excerpt_position: ExcerptDimension<MBD>,
5457        diff_transforms: &mut Cursor<
5458            DiffTransform,
5459            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5460        >,
5461    ) -> MBD
5462    where
5463        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5464    {
5465        loop {
5466            let transform_end_position = diff_transforms.end().0;
5467            let at_transform_end =
5468                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5469            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5470                diff_transforms.next();
5471                continue;
5472            }
5473
5474            let mut position = diff_transforms.start().1;
5475            match diff_transforms.item() {
5476                Some(DiffTransform::DeletedHunk {
5477                    buffer_id,
5478                    base_text_byte_range,
5479                    ..
5480                }) => {
5481                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5482                        && let Some(base_text) =
5483                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5484                        && diff_base_anchor.is_valid(&base_text)
5485                    {
5486                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5487                        if base_text_offset >= base_text_byte_range.start
5488                            && base_text_offset <= base_text_byte_range.end
5489                        {
5490                            let position_in_hunk = base_text
5491                                .text_summary_for_range::<MBD::TextDimension, _>(
5492                                    base_text_byte_range.start..base_text_offset,
5493                                );
5494                            position.0.add_text_dim(&position_in_hunk);
5495                        } else if at_transform_end {
5496                            diff_transforms.next();
5497                            continue;
5498                        }
5499                    }
5500                }
5501                _ => {
5502                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5503                        diff_transforms.next();
5504                        continue;
5505                    }
5506                    let overshoot = excerpt_position - diff_transforms.start().0;
5507                    position += overshoot;
5508                }
5509            }
5510
5511            return position.0;
5512        }
5513    }
5514
5515    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5516        let mut cursor = self
5517            .excerpts
5518            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5519        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5520
5521        cursor.seek(&Some(locator), Bias::Left);
5522        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5523            cursor.prev();
5524        }
5525
5526        let mut position = cursor.start().1;
5527        if let Some(excerpt) = cursor.item()
5528            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5529        {
5530            let excerpt_buffer_start = excerpt
5531                .buffer
5532                .offset_for_anchor(&excerpt.range.context.start);
5533            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5534            let buffer_position = cmp::min(
5535                excerpt_buffer_end,
5536                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5537            );
5538            if buffer_position > excerpt_buffer_start {
5539                position += buffer_position - excerpt_buffer_start;
5540            }
5541        }
5542        position
5543    }
5544
5545    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5546        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5547            excerpt_id = *replacement;
5548        }
5549        excerpt_id
5550    }
5551
5552    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5553    where
5554        MBD: MultiBufferDimension
5555            + Ord
5556            + Sub<Output = MBD::TextDimension>
5557            + AddAssign<MBD::TextDimension>,
5558        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5559        I: 'a + IntoIterator<Item = &'a Anchor>,
5560    {
5561        let mut anchors = anchors.into_iter().peekable();
5562        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5563        let mut diff_transforms_cursor = self
5564            .diff_transforms
5565            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5566        diff_transforms_cursor.next();
5567
5568        let mut summaries = Vec::new();
5569        while let Some(anchor) = anchors.peek() {
5570            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5571
5572            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5573                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5574            });
5575
5576            let locator = self.excerpt_locator_for_id(excerpt_id);
5577            cursor.seek_forward(locator, Bias::Left);
5578            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5579                cursor.prev();
5580            }
5581
5582            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5583            if let Some(excerpt) = cursor.item() {
5584                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5585                    let position = self.resolve_summary_for_anchor(
5586                        &Anchor::min(),
5587                        excerpt_start_position,
5588                        &mut diff_transforms_cursor,
5589                    );
5590                    summaries.extend(excerpt_anchors.map(|_| position));
5591                    continue;
5592                }
5593                let excerpt_buffer_start = excerpt
5594                    .range
5595                    .context
5596                    .start
5597                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5598                let excerpt_buffer_end = excerpt
5599                    .range
5600                    .context
5601                    .end
5602                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5603                for (buffer_summary, anchor) in excerpt
5604                    .buffer
5605                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5606                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5607                    )
5608                {
5609                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5610                    let mut position = excerpt_start_position;
5611                    if summary > excerpt_buffer_start {
5612                        position += summary - excerpt_buffer_start;
5613                    }
5614
5615                    if diff_transforms_cursor.start().0 < position {
5616                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5617                    }
5618
5619                    summaries.push(self.resolve_summary_for_anchor(
5620                        anchor,
5621                        position,
5622                        &mut diff_transforms_cursor,
5623                    ));
5624                }
5625            } else {
5626                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5627                let position = self.resolve_summary_for_anchor(
5628                    &Anchor::max(),
5629                    excerpt_start_position,
5630                    &mut diff_transforms_cursor,
5631                );
5632                summaries.extend(excerpt_anchors.map(|_| position));
5633            }
5634        }
5635
5636        summaries
5637    }
5638
5639    pub fn dimensions_from_points<'a, MBD>(
5640        &'a self,
5641        points: impl 'a + IntoIterator<Item = Point>,
5642    ) -> impl 'a + Iterator<Item = MBD>
5643    where
5644        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5645    {
5646        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5647        cursor.seek(&DimensionPair {
5648            key: Point::default(),
5649            value: None,
5650        });
5651        let mut points = points.into_iter();
5652        iter::from_fn(move || {
5653            let point = points.next()?;
5654
5655            cursor.seek_forward(&DimensionPair {
5656                key: point,
5657                value: None,
5658            });
5659
5660            if let Some(region) = cursor.region() {
5661                let overshoot = point - region.range.start.key;
5662                let buffer_point = region.buffer_range.start + overshoot;
5663                let mut position = region.range.start.value.unwrap();
5664                position.add_text_dim(
5665                    &region
5666                        .buffer
5667                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5668                );
5669                if point == region.range.end.key && region.has_trailing_newline {
5670                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5671                }
5672                Some(position)
5673            } else {
5674                Some(MBD::from_summary(&self.text_summary()))
5675            }
5676        })
5677    }
5678
5679    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5680    where
5681        I: 'a + IntoIterator<Item = &'a Anchor>,
5682    {
5683        let mut anchors = anchors.into_iter().enumerate().peekable();
5684        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5685        cursor.next();
5686
5687        let mut result = Vec::new();
5688
5689        while let Some((_, anchor)) = anchors.peek() {
5690            let old_excerpt_id = anchor.excerpt_id;
5691
5692            // Find the location where this anchor's excerpt should be.
5693            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5694            cursor.seek_forward(&Some(old_locator), Bias::Left);
5695
5696            let next_excerpt = cursor.item();
5697            let prev_excerpt = cursor.prev_item();
5698
5699            // Process all of the anchors for this excerpt.
5700            while let Some((anchor_ix, &anchor)) =
5701                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5702            {
5703                let mut anchor = anchor;
5704
5705                // Leave min and max anchors unchanged if invalid or
5706                // if the old excerpt still exists at this location
5707                let mut kept_position = next_excerpt
5708                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5709                    || old_excerpt_id == ExcerptId::max()
5710                    || old_excerpt_id == ExcerptId::min();
5711
5712                // If the old excerpt no longer exists at this location, then attempt to
5713                // find an equivalent position for this anchor in an adjacent excerpt.
5714                if !kept_position {
5715                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5716                        if excerpt.contains(&anchor) {
5717                            anchor.excerpt_id = excerpt.id;
5718                            kept_position = true;
5719                            break;
5720                        }
5721                    }
5722                }
5723
5724                // If there's no adjacent excerpt that contains the anchor's position,
5725                // then report that the anchor has lost its position.
5726                if !kept_position {
5727                    anchor = if let Some(excerpt) = next_excerpt {
5728                        let mut text_anchor = excerpt
5729                            .range
5730                            .context
5731                            .start
5732                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5733                        if text_anchor
5734                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5735                            .is_gt()
5736                        {
5737                            text_anchor = excerpt.range.context.end;
5738                        }
5739                        Anchor::in_buffer(excerpt.id, text_anchor)
5740                    } else if let Some(excerpt) = prev_excerpt {
5741                        let mut text_anchor = excerpt
5742                            .range
5743                            .context
5744                            .end
5745                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5746                        if text_anchor
5747                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5748                            .is_lt()
5749                        {
5750                            text_anchor = excerpt.range.context.start;
5751                        }
5752                        Anchor::in_buffer(excerpt.id, text_anchor)
5753                    } else if anchor.text_anchor.bias == Bias::Left {
5754                        Anchor::min()
5755                    } else {
5756                        Anchor::max()
5757                    };
5758                }
5759
5760                result.push((anchor_ix, anchor, kept_position));
5761            }
5762        }
5763        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5764        result
5765    }
5766
5767    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5768        self.anchor_at(position, Bias::Left)
5769    }
5770
5771    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5772        self.anchor_at(position, Bias::Right)
5773    }
5774
5775    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5776        let offset = position.to_offset(self);
5777
5778        // Find the given position in the diff transforms. Determine the corresponding
5779        // offset in the excerpts, and whether the position is within a deleted hunk.
5780        let mut diff_transforms = self
5781            .diff_transforms
5782            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5783        diff_transforms.seek(&offset, Bias::Right);
5784
5785        if offset == diff_transforms.start().0
5786            && bias == Bias::Left
5787            && let Some(prev_item) = diff_transforms.prev_item()
5788            && let DiffTransform::DeletedHunk { .. } = prev_item
5789        {
5790            diff_transforms.prev();
5791        }
5792        let offset_in_transform = offset - diff_transforms.start().0;
5793        let mut excerpt_offset = diff_transforms.start().1;
5794        let mut diff_base_anchor = None;
5795        if let Some(DiffTransform::DeletedHunk {
5796            buffer_id,
5797            base_text_byte_range,
5798            has_trailing_newline,
5799            ..
5800        }) = diff_transforms.item()
5801        {
5802            let diff = self.diffs.get(buffer_id).expect("missing diff");
5803            if offset_in_transform > base_text_byte_range.len() {
5804                debug_assert!(*has_trailing_newline);
5805                bias = Bias::Right;
5806            } else {
5807                diff_base_anchor = Some(
5808                    diff.base_text()
5809                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5810                );
5811                bias = Bias::Left;
5812            }
5813        } else {
5814            excerpt_offset += MultiBufferOffset(offset_in_transform);
5815        };
5816
5817        let mut excerpts = self
5818            .excerpts
5819            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5820        excerpts.seek(&excerpt_offset, Bias::Right);
5821        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5822            excerpts.prev();
5823        }
5824        if let Some(excerpt) = excerpts.item() {
5825            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5826            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5827                overshoot -= 1;
5828                bias = Bias::Right;
5829            }
5830
5831            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5832            let text_anchor =
5833                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5834            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5835            match diff_base_anchor {
5836                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5837                None => anchor,
5838            }
5839        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5840        {
5841            Anchor::min()
5842        } else {
5843            Anchor::max()
5844        }
5845    }
5846
5847    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5848    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5849        let (excerpt, buffer, _) = self.as_singleton()?;
5850        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5851            Some(Anchor::in_buffer(excerpt, text_anchor))
5852        } else {
5853            None
5854        }
5855    }
5856
5857    /// Returns an anchor for the given excerpt and text anchor,
5858    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5859    pub fn anchor_range_in_excerpt(
5860        &self,
5861        excerpt_id: ExcerptId,
5862        text_anchor: Range<text::Anchor>,
5863    ) -> Option<Range<Anchor>> {
5864        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5865
5866        Some(
5867            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5868                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5869        )
5870    }
5871
5872    /// Returns an anchor for the given excerpt and text anchor,
5873    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5874    pub fn anchor_in_excerpt(
5875        &self,
5876        excerpt_id: ExcerptId,
5877        text_anchor: text::Anchor,
5878    ) -> Option<Anchor> {
5879        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5880        Self::anchor_in_excerpt_(excerpt, text_anchor)
5881    }
5882
5883    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5884    pub fn anchors_in_excerpt(
5885        &self,
5886        excerpt_id: ExcerptId,
5887        text_anchors: impl IntoIterator<Item = text::Anchor>,
5888    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5889        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5890        Some(
5891            text_anchors
5892                .into_iter()
5893                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5894        )
5895    }
5896
5897    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5898        match text_anchor.buffer_id {
5899            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5900            Some(_) => return None,
5901            None if text_anchor.is_max() || text_anchor.is_min() => {
5902                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5903            }
5904            None => return None,
5905        }
5906
5907        let context = &excerpt.range.context;
5908        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5909            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5910        {
5911            return None;
5912        }
5913
5914        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5915    }
5916
5917    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5918        Some(self.excerpt(excerpt_id)?.range.context.clone())
5919    }
5920
5921    pub fn excerpt_range_for_excerpt(
5922        &self,
5923        excerpt_id: ExcerptId,
5924    ) -> Option<ExcerptRange<text::Anchor>> {
5925        Some(self.excerpt(excerpt_id)?.range.clone())
5926    }
5927
5928    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5929        if anchor.is_min() || anchor.is_max() {
5930            // todo(lw): should be `!self.is_empty()`
5931            true
5932        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5933            excerpt.buffer.can_resolve(&anchor.text_anchor)
5934        } else {
5935            false
5936        }
5937    }
5938
5939    pub fn excerpts(
5940        &self,
5941    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5942        self.excerpts
5943            .iter()
5944            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5945    }
5946
5947    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5948    where
5949        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5950        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5951    {
5952        let excerpts = self.excerpts.cursor(());
5953        let diff_transforms = self.diff_transforms.cursor(());
5954        MultiBufferCursor {
5955            excerpts,
5956            diff_transforms,
5957            diffs: &self.diffs,
5958            cached_region: OnceCell::new(),
5959        }
5960    }
5961
5962    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5963        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5964        let mut excerpts = self
5965            .excerpts
5966            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5967        excerpts.seek(&Some(start_locator), Bias::Left);
5968        excerpts.prev();
5969
5970        let mut diff_transforms = self
5971            .diff_transforms
5972            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5973        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5974        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5975            diff_transforms.next();
5976        }
5977
5978        let excerpt = excerpts.item()?;
5979        Some(MultiBufferExcerpt {
5980            excerpt,
5981            offset: diff_transforms.start().output_dimension.0,
5982            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5983            excerpt_offset: excerpts.start().1,
5984            diff_transforms,
5985        })
5986    }
5987
5988    pub fn excerpt_boundaries_in_range<R, T>(
5989        &self,
5990        range: R,
5991    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5992    where
5993        R: RangeBounds<T>,
5994        T: ToOffset,
5995    {
5996        let start_offset;
5997        let start = match range.start_bound() {
5998            Bound::Included(start) => {
5999                start_offset = start.to_offset(self);
6000                Bound::Included(start_offset)
6001            }
6002            Bound::Excluded(_) => {
6003                panic!("not supported")
6004            }
6005            Bound::Unbounded => {
6006                start_offset = MultiBufferOffset::ZERO;
6007                Bound::Unbounded
6008            }
6009        };
6010        let end = match range.end_bound() {
6011            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6012            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6013            Bound::Unbounded => Bound::Unbounded,
6014        };
6015        let bounds = (start, end);
6016        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6017        cursor.seek(&DimensionPair {
6018            key: start_offset,
6019            value: None,
6020        });
6021
6022        if cursor
6023            .fetch_excerpt_with_range()
6024            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6025        {
6026            cursor.prev_excerpt();
6027        } else {
6028            cursor.seek_to_start_of_current_excerpt();
6029        }
6030        let mut prev_region = cursor
6031            .fetch_excerpt_with_range()
6032            .map(|(excerpt, _)| excerpt);
6033
6034        cursor.next_excerpt_forwards();
6035
6036        iter::from_fn(move || {
6037            loop {
6038                if self.singleton {
6039                    return None;
6040                }
6041
6042                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6043                cursor.next_excerpt_forwards();
6044                if !bounds.contains(&next_range.start.key) {
6045                    prev_region = Some(next_excerpt);
6046                    continue;
6047                }
6048
6049                let next_region_start = next_range.start.value.unwrap();
6050                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6051                    range.start.value.unwrap()
6052                } else {
6053                    self.max_point()
6054                };
6055
6056                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6057                    id: region.id,
6058                    buffer: region.buffer.clone(),
6059                    buffer_id: region.buffer_id,
6060                    range: region.range.clone(),
6061                    end_row: MultiBufferRow(next_region_start.row),
6062                });
6063
6064                let next = ExcerptInfo {
6065                    id: next_excerpt.id,
6066                    buffer: next_excerpt.buffer.clone(),
6067                    buffer_id: next_excerpt.buffer_id,
6068                    range: next_excerpt.range.clone(),
6069                    end_row: if next_excerpt.has_trailing_newline {
6070                        MultiBufferRow(next_region_end.row - 1)
6071                    } else {
6072                        MultiBufferRow(next_region_end.row)
6073                    },
6074                };
6075
6076                let row = MultiBufferRow(next_region_start.row);
6077
6078                prev_region = Some(next_excerpt);
6079
6080                return Some(ExcerptBoundary { row, prev, next });
6081            }
6082        })
6083    }
6084
6085    pub fn edit_count(&self) -> usize {
6086        self.edit_count
6087    }
6088
6089    pub fn non_text_state_update_count(&self) -> usize {
6090        self.non_text_state_update_count
6091    }
6092
6093    /// Returns the smallest enclosing bracket ranges containing the given range or
6094    /// None if no brackets contain range or the range is not contained in a single
6095    /// excerpt
6096    ///
6097    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6098    #[ztracing::instrument(skip_all)]
6099    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6100        &self,
6101        range: Range<T>,
6102        range_filter: Option<
6103            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6104        >,
6105    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6106        let range = range.start.to_offset(self)..range.end.to_offset(self);
6107        let mut excerpt = self.excerpt_containing(range.clone())?;
6108        let buffer = excerpt.buffer();
6109        let excerpt_buffer_range = excerpt.buffer_range();
6110
6111        // Filter to ranges contained in the excerpt
6112        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6113            excerpt_buffer_range.contains(&BufferOffset(open.start))
6114                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6115                && range_filter.is_none_or(|filter| {
6116                    filter(
6117                        buffer,
6118                        BufferOffset(open.start)..BufferOffset(close.end),
6119                        BufferOffset(close.start)..BufferOffset(close.end),
6120                    )
6121                })
6122        };
6123
6124        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6125            excerpt.map_range_to_buffer(range),
6126            Some(&range_filter),
6127        )?;
6128
6129        Some((
6130            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6131            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6132        ))
6133    }
6134
6135    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6136    /// not contained in a single excerpt
6137    pub fn enclosing_bracket_ranges<T: ToOffset>(
6138        &self,
6139        range: Range<T>,
6140    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6141    {
6142        let range = range.start.to_offset(self)..range.end.to_offset(self);
6143        let mut excerpt = self.excerpt_containing(range.clone())?;
6144
6145        Some(
6146            excerpt
6147                .buffer()
6148                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6149                .filter_map(move |pair| {
6150                    let open_range =
6151                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6152                    let close_range =
6153                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6154                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6155                        Some((
6156                            excerpt.map_range_from_buffer(open_range),
6157                            excerpt.map_range_from_buffer(close_range),
6158                        ))
6159                    } else {
6160                        None
6161                    }
6162                }),
6163        )
6164    }
6165
6166    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6167    /// not contained in a single excerpt
6168    pub fn text_object_ranges<T: ToOffset>(
6169        &self,
6170        range: Range<T>,
6171        options: TreeSitterOptions,
6172    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6173        let range = range.start.to_offset(self)..range.end.to_offset(self);
6174        self.excerpt_containing(range.clone())
6175            .map(|mut excerpt| {
6176                excerpt
6177                    .buffer()
6178                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6179                    .filter_map(move |(range, text_object)| {
6180                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6181                        if excerpt.contains_buffer_range(range.clone()) {
6182                            Some((excerpt.map_range_from_buffer(range), text_object))
6183                        } else {
6184                            None
6185                        }
6186                    })
6187            })
6188            .into_iter()
6189            .flatten()
6190    }
6191
6192    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6193    /// not contained in a single excerpt
6194    pub fn bracket_ranges<T: ToOffset>(
6195        &self,
6196        range: Range<T>,
6197    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6198    {
6199        let range = range.start.to_offset(self)..range.end.to_offset(self);
6200        let mut excerpt = self.excerpt_containing(range.clone())?;
6201        Some(
6202            excerpt
6203                .buffer()
6204                .bracket_ranges(excerpt.map_range_to_buffer(range))
6205                .filter_map(move |pair| {
6206                    let open_range =
6207                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6208                    let close_range =
6209                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6210                    excerpt
6211                        .contains_buffer_range(open_range.start..close_range.end)
6212                        .then(|| BracketMatch {
6213                            open_range: excerpt.map_range_from_buffer(open_range),
6214                            close_range: excerpt.map_range_from_buffer(close_range),
6215                            color_index: pair.color_index,
6216                            newline_only: pair.newline_only,
6217                            syntax_layer_depth: pair.syntax_layer_depth,
6218                        })
6219                })
6220                .map(BracketMatch::bracket_ranges),
6221        )
6222    }
6223
6224    pub fn redacted_ranges<'a, T: ToOffset>(
6225        &'a self,
6226        range: Range<T>,
6227        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6228    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6229        let range = range.start.to_offset(self)..range.end.to_offset(self);
6230        self.lift_buffer_metadata(range, move |buffer, range| {
6231            if redaction_enabled(buffer.file()) {
6232                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6233            } else {
6234                None
6235            }
6236        })
6237        .map(|(range, _, _)| range)
6238    }
6239
6240    pub fn runnable_ranges(
6241        &self,
6242        range: Range<Anchor>,
6243    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6244        let range = range.start.to_offset(self)..range.end.to_offset(self);
6245        self.lift_buffer_metadata(range, move |buffer, range| {
6246            Some(
6247                buffer
6248                    .runnable_ranges(range.clone())
6249                    .filter(move |runnable| {
6250                        runnable.run_range.start >= range.start
6251                            && runnable.run_range.end < range.end
6252                    })
6253                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6254            )
6255        })
6256        .map(|(run_range, runnable, _)| (run_range, runnable))
6257    }
6258
6259    pub fn line_indents(
6260        &self,
6261        start_row: MultiBufferRow,
6262        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6263    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6264        let max_point = self.max_point();
6265        let mut cursor = self.cursor::<Point, Point>();
6266        cursor.seek(&Point::new(start_row.0, 0));
6267        iter::from_fn(move || {
6268            let mut region = cursor.region()?;
6269            while !buffer_filter(&region.excerpt.buffer) {
6270                cursor.next();
6271                region = cursor.region()?;
6272            }
6273            let region = cursor.region()?;
6274            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6275            let buffer_start_row =
6276                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6277
6278            let buffer_end_row = if region.is_main_buffer
6279                && (region.has_trailing_newline || region.range.end == max_point)
6280            {
6281                region.buffer_range.end.row
6282            } else {
6283                region.buffer_range.end.row.saturating_sub(1)
6284            };
6285
6286            let line_indents = region
6287                .buffer
6288                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6289            let region_buffer_row = region.buffer_range.start.row;
6290            let region_row = region.range.start.row;
6291            let region_buffer = &region.excerpt.buffer;
6292            cursor.next();
6293            Some(line_indents.map(move |(buffer_row, indent)| {
6294                let row = region_row + (buffer_row - region_buffer_row);
6295                (MultiBufferRow(row), indent, region_buffer.as_ref())
6296            }))
6297        })
6298        .flatten()
6299    }
6300
6301    pub fn reversed_line_indents(
6302        &self,
6303        end_row: MultiBufferRow,
6304        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6305    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6306        let max_point = self.max_point();
6307        let mut cursor = self.cursor::<Point, Point>();
6308        cursor.seek(&Point::new(end_row.0, 0));
6309        iter::from_fn(move || {
6310            let mut region = cursor.region()?;
6311            while !buffer_filter(&region.excerpt.buffer) {
6312                cursor.prev();
6313                region = cursor.region()?;
6314            }
6315            let region = cursor.region()?;
6316
6317            let buffer_start_row = region.buffer_range.start.row;
6318            let buffer_end_row = if region.is_main_buffer
6319                && (region.has_trailing_newline || region.range.end == max_point)
6320            {
6321                region.buffer_range.end.row + 1
6322            } else {
6323                region.buffer_range.end.row
6324            };
6325
6326            let overshoot = end_row.0 - region.range.start.row;
6327            let buffer_end_row =
6328                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6329
6330            let line_indents = region
6331                .buffer
6332                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6333            let region_buffer_row = region.buffer_range.start.row;
6334            let region_row = region.range.start.row;
6335            let region_buffer = &region.excerpt.buffer;
6336            cursor.prev();
6337            Some(line_indents.map(move |(buffer_row, indent)| {
6338                let row = region_row + (buffer_row - region_buffer_row);
6339                (MultiBufferRow(row), indent, region_buffer.as_ref())
6340            }))
6341        })
6342        .flatten()
6343    }
6344
6345    pub async fn enclosing_indent(
6346        &self,
6347        mut target_row: MultiBufferRow,
6348    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6349        let max_row = MultiBufferRow(self.max_point().row);
6350        if target_row >= max_row {
6351            return None;
6352        }
6353
6354        let mut target_indent = self.line_indent_for_row(target_row);
6355
6356        // If the current row is at the start of an indented block, we want to return this
6357        // block as the enclosing indent.
6358        if !target_indent.is_line_empty() && target_row < max_row {
6359            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6360            if !next_line_indent.is_line_empty()
6361                && target_indent.raw_len() < next_line_indent.raw_len()
6362            {
6363                target_indent = next_line_indent;
6364                target_row.0 += 1;
6365            }
6366        }
6367
6368        const SEARCH_ROW_LIMIT: u32 = 25000;
6369        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6370        const YIELD_INTERVAL: u32 = 100;
6371
6372        let mut accessed_row_counter = 0;
6373
6374        // If there is a blank line at the current row, search for the next non indented lines
6375        if target_indent.is_line_empty() {
6376            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6377            let end =
6378                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6379
6380            let mut non_empty_line_above = None;
6381            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6382                if row < start {
6383                    break;
6384                }
6385                accessed_row_counter += 1;
6386                if accessed_row_counter == YIELD_INTERVAL {
6387                    accessed_row_counter = 0;
6388                    yield_now().await;
6389                }
6390                if !indent.is_line_empty() {
6391                    non_empty_line_above = Some((row, indent));
6392                    break;
6393                }
6394            }
6395
6396            let mut non_empty_line_below = None;
6397            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6398                if row > end {
6399                    break;
6400                }
6401                accessed_row_counter += 1;
6402                if accessed_row_counter == YIELD_INTERVAL {
6403                    accessed_row_counter = 0;
6404                    yield_now().await;
6405                }
6406                if !indent.is_line_empty() {
6407                    non_empty_line_below = Some((row, indent));
6408                    break;
6409                }
6410            }
6411
6412            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6413                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6414                    if above_indent.raw_len() >= below_indent.raw_len() {
6415                        (above_row, above_indent)
6416                    } else {
6417                        (below_row, below_indent)
6418                    }
6419                }
6420                (Some(above), None) => above,
6421                (None, Some(below)) => below,
6422                _ => return None,
6423            };
6424
6425            target_indent = indent;
6426            target_row = row;
6427        }
6428
6429        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6430        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6431
6432        let mut start_indent = None;
6433        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6434            if row < start {
6435                break;
6436            }
6437            accessed_row_counter += 1;
6438            if accessed_row_counter == YIELD_INTERVAL {
6439                accessed_row_counter = 0;
6440                yield_now().await;
6441            }
6442            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6443                start_indent = Some((row, indent));
6444                break;
6445            }
6446        }
6447        let (start_row, start_indent_size) = start_indent?;
6448
6449        let mut end_indent = (end, None);
6450        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6451            if row > end {
6452                break;
6453            }
6454            accessed_row_counter += 1;
6455            if accessed_row_counter == YIELD_INTERVAL {
6456                accessed_row_counter = 0;
6457                yield_now().await;
6458            }
6459            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6460                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6461                break;
6462            }
6463        }
6464        let (end_row, end_indent_size) = end_indent;
6465
6466        let indent = if let Some(end_indent_size) = end_indent_size {
6467            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6468                start_indent_size
6469            } else {
6470                end_indent_size
6471            }
6472        } else {
6473            start_indent_size
6474        };
6475
6476        Some((start_row..end_row, indent))
6477    }
6478
6479    pub fn indent_guides_in_range<T: ToPoint>(
6480        &self,
6481        range: Range<T>,
6482        ignore_disabled_for_language: bool,
6483        cx: &App,
6484    ) -> impl Iterator<Item = IndentGuide> {
6485        let range = range.start.to_point(self)..range.end.to_point(self);
6486        let start_row = MultiBufferRow(range.start.row);
6487        let end_row = MultiBufferRow(range.end.row);
6488
6489        let mut row_indents = self.line_indents(start_row, |buffer| {
6490            let settings =
6491                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6492            settings.indent_guides.enabled || ignore_disabled_for_language
6493        });
6494
6495        let mut result = Vec::new();
6496        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6497
6498        let mut prev_settings = None;
6499        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6500            if first_row > end_row {
6501                break;
6502            }
6503            let current_depth = indent_stack.len() as u32;
6504
6505            // Avoid retrieving the language settings repeatedly for every buffer row.
6506            if let Some((prev_buffer_id, _)) = &prev_settings
6507                && prev_buffer_id != &buffer.remote_id()
6508            {
6509                prev_settings.take();
6510            }
6511            let settings = &prev_settings
6512                .get_or_insert_with(|| {
6513                    (
6514                        buffer.remote_id(),
6515                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6516                    )
6517                })
6518                .1;
6519            let tab_size = settings.tab_size.get();
6520
6521            // When encountering empty, continue until found useful line indent
6522            // then add to the indent stack with the depth found
6523            let mut found_indent = false;
6524            let mut last_row = first_row;
6525            if line_indent.is_line_blank() {
6526                while !found_indent {
6527                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6528                        break;
6529                    };
6530                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6531                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6532                        break;
6533                    }
6534
6535                    if new_line_indent.is_line_blank() {
6536                        continue;
6537                    }
6538                    last_row = target_row.min(end_row);
6539                    line_indent = new_line_indent;
6540                    found_indent = true;
6541                    break;
6542                }
6543            } else {
6544                found_indent = true
6545            }
6546
6547            let depth = if found_indent {
6548                line_indent.len(tab_size) / tab_size
6549            } else {
6550                0
6551            };
6552
6553            match depth.cmp(&current_depth) {
6554                cmp::Ordering::Less => {
6555                    for _ in 0..(current_depth - depth) {
6556                        let mut indent = indent_stack.pop().unwrap();
6557                        if last_row != first_row {
6558                            // In this case, we landed on an empty row, had to seek forward,
6559                            // and discovered that the indent we where on is ending.
6560                            // This means that the last display row must
6561                            // be on line that ends this indent range, so we
6562                            // should display the range up to the first non-empty line
6563                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6564                        }
6565
6566                        result.push(indent)
6567                    }
6568                }
6569                cmp::Ordering::Greater => {
6570                    for next_depth in current_depth..depth {
6571                        indent_stack.push(IndentGuide {
6572                            buffer_id: buffer.remote_id(),
6573                            start_row: first_row,
6574                            end_row: last_row,
6575                            depth: next_depth,
6576                            tab_size,
6577                            settings: settings.indent_guides.clone(),
6578                        });
6579                    }
6580                }
6581                _ => {}
6582            }
6583
6584            for indent in indent_stack.iter_mut() {
6585                indent.end_row = last_row;
6586            }
6587        }
6588
6589        result.extend(indent_stack);
6590        result.into_iter()
6591    }
6592
6593    pub fn trailing_excerpt_update_count(&self) -> usize {
6594        self.trailing_excerpt_update_count
6595    }
6596
6597    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6598        self.point_to_buffer_offset(point)
6599            .and_then(|(buffer, _)| buffer.file())
6600    }
6601
6602    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6603        self.point_to_buffer_offset(offset)
6604            .and_then(|(buffer, offset)| buffer.language_at(offset))
6605    }
6606
6607    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6608        self.excerpts
6609            .first()
6610            .map(|excerpt| &excerpt.buffer)
6611            .map(|buffer| {
6612                language_settings(
6613                    buffer.language().map(|language| language.name()),
6614                    buffer.file(),
6615                    cx,
6616                )
6617            })
6618            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6619    }
6620
6621    pub fn language_settings_at<'a, T: ToOffset>(
6622        &'a self,
6623        point: T,
6624        cx: &'a App,
6625    ) -> Cow<'a, LanguageSettings> {
6626        let mut language = None;
6627        let mut file = None;
6628        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6629            language = buffer.language_at(offset);
6630            file = buffer.file();
6631        }
6632        language_settings(language.map(|l| l.name()), file, cx)
6633    }
6634
6635    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6636        self.point_to_buffer_offset(point)
6637            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6638    }
6639
6640    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6641        self.point_to_buffer_offset(point)
6642            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6643            .unwrap_or_default()
6644    }
6645
6646    pub fn language_indent_size_at<T: ToOffset>(
6647        &self,
6648        position: T,
6649        cx: &App,
6650    ) -> Option<IndentSize> {
6651        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6652        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6653    }
6654
6655    pub fn is_dirty(&self) -> bool {
6656        self.is_dirty
6657    }
6658
6659    pub fn has_deleted_file(&self) -> bool {
6660        self.has_deleted_file
6661    }
6662
6663    pub fn has_conflict(&self) -> bool {
6664        self.has_conflict
6665    }
6666
6667    pub fn has_diagnostics(&self) -> bool {
6668        self.excerpts
6669            .iter()
6670            .any(|excerpt| excerpt.buffer.has_diagnostics())
6671    }
6672
6673    pub fn diagnostic_group(
6674        &self,
6675        buffer_id: BufferId,
6676        group_id: usize,
6677    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6678        self.lift_buffer_metadata::<Point, _, _>(
6679            Point::zero()..self.max_point(),
6680            move |buffer, range| {
6681                if buffer.remote_id() != buffer_id {
6682                    return None;
6683                };
6684                Some(
6685                    buffer
6686                        .diagnostics_in_range(range, false)
6687                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6688                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6689                )
6690            },
6691        )
6692        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6693    }
6694
6695    pub fn diagnostics_in_range<'a, MBD>(
6696        &'a self,
6697        range: Range<MBD>,
6698    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6699    where
6700        MBD::TextDimension: 'a
6701            + text::ToOffset
6702            + text::FromAnchor
6703            + Sub<Output = MBD::TextDimension>
6704            + fmt::Debug
6705            + ops::Add<Output = MBD::TextDimension>
6706            + ops::AddAssign
6707            + Ord,
6708        MBD: MultiBufferDimension
6709            + Ord
6710            + Sub<Output = MBD::TextDimension>
6711            + ops::Add<MBD::TextDimension, Output = MBD>
6712            + ops::AddAssign<MBD::TextDimension>
6713            + 'a,
6714    {
6715        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6716            Some(
6717                buffer
6718                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6719                    .map(|entry| (entry.range, entry.diagnostic)),
6720            )
6721        })
6722        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6723    }
6724
6725    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6726        &'a self,
6727        range: Range<MBD>,
6728    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6729    where
6730        MBD: MultiBufferDimension
6731            + Ord
6732            + Sub<Output = MBD::TextDimension>
6733            + ops::Add<MBD::TextDimension, Output = MBD>
6734            + ops::AddAssign<MBD::TextDimension>,
6735        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6736            + ops::Add<Output = MBD::TextDimension>
6737            + text::ToOffset
6738            + text::FromAnchor
6739            + AddAssign<MBD::TextDimension>
6740            + Ord,
6741    {
6742        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6743            Some(
6744                buffer
6745                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6746                    .map(|entry| (entry.range, entry.diagnostic)),
6747            )
6748        })
6749        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6750    }
6751
6752    pub fn syntax_ancestor<T: ToOffset>(
6753        &self,
6754        range: Range<T>,
6755    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6756        let range = range.start.to_offset(self)..range.end.to_offset(self);
6757        let mut excerpt = self.excerpt_containing(range.clone())?;
6758        let node = excerpt
6759            .buffer()
6760            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6761        let node_range = node.byte_range();
6762        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6763        if !excerpt.contains_buffer_range(node_range.clone()) {
6764            return None;
6765        };
6766        Some((node, excerpt.map_range_from_buffer(node_range)))
6767    }
6768
6769    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6770        let (excerpt_id, _, buffer) = self.as_singleton()?;
6771        let outline = buffer.outline(theme);
6772        Some(Outline::new(
6773            outline
6774                .items
6775                .into_iter()
6776                .flat_map(|item| {
6777                    Some(OutlineItem {
6778                        depth: item.depth,
6779                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6780                        source_range_for_text: self
6781                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6782                        text: item.text,
6783                        highlight_ranges: item.highlight_ranges,
6784                        name_ranges: item.name_ranges,
6785                        body_range: item.body_range.and_then(|body_range| {
6786                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6787                        }),
6788                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6789                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6790                        }),
6791                    })
6792                })
6793                .collect(),
6794        ))
6795    }
6796
6797    pub fn symbols_containing<T: ToOffset>(
6798        &self,
6799        offset: T,
6800        theme: Option<&SyntaxTheme>,
6801    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6802        let anchor = self.anchor_before(offset);
6803        let excerpt @ &Excerpt {
6804            id: excerpt_id,
6805            buffer_id,
6806            ref buffer,
6807            ..
6808        } = self.excerpt(anchor.excerpt_id)?;
6809        if cfg!(debug_assertions) {
6810            match anchor.text_anchor.buffer_id {
6811                // we clearly are hitting this according to sentry, but in what situations can this occur?
6812                Some(anchor_buffer_id) => {
6813                    assert_eq!(
6814                        anchor_buffer_id, buffer_id,
6815                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6816                    )
6817                }
6818                None => assert!(anchor.is_max()),
6819            }
6820        };
6821        Some((
6822            buffer_id,
6823            buffer
6824                .symbols_containing(anchor.text_anchor, theme)
6825                .into_iter()
6826                .flat_map(|item| {
6827                    Some(OutlineItem {
6828                        depth: item.depth,
6829                        source_range_for_text: Anchor::range_in_buffer(
6830                            excerpt_id,
6831                            item.source_range_for_text,
6832                        ),
6833                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6834                        text: item.text,
6835                        highlight_ranges: item.highlight_ranges,
6836                        name_ranges: item.name_ranges,
6837                        body_range: item
6838                            .body_range
6839                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6840                        annotation_range: item
6841                            .annotation_range
6842                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6843                    })
6844                })
6845                .collect(),
6846        ))
6847    }
6848
6849    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6850        self.try_excerpt_locator_for_id(id)
6851            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6852    }
6853
6854    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6855        if id == ExcerptId::min() {
6856            Some(Locator::min_ref())
6857        } else if id == ExcerptId::max() {
6858            Some(Locator::max_ref())
6859        } else {
6860            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6861            if let Some(entry) = item
6862                && entry.id == id
6863            {
6864                return Some(&entry.locator);
6865            }
6866            None
6867        }
6868    }
6869
6870    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6871    fn excerpt_locators_for_ids(
6872        &self,
6873        ids: impl IntoIterator<Item = ExcerptId>,
6874    ) -> SmallVec<[Locator; 1]> {
6875        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6876        sorted_ids.sort_unstable();
6877        sorted_ids.dedup();
6878        let mut locators = SmallVec::new();
6879
6880        while sorted_ids.last() == Some(&ExcerptId::max()) {
6881            sorted_ids.pop();
6882            locators.push(Locator::max());
6883        }
6884
6885        let mut sorted_ids = sorted_ids.into_iter().peekable();
6886        locators.extend(
6887            sorted_ids
6888                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6889                .map(|_| Locator::min()),
6890        );
6891
6892        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6893        for id in sorted_ids {
6894            if cursor.seek_forward(&id, Bias::Left) {
6895                locators.push(cursor.item().unwrap().locator.clone());
6896            } else {
6897                panic!("invalid excerpt id {:?}", id);
6898            }
6899        }
6900
6901        locators.sort_unstable();
6902        locators
6903    }
6904
6905    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6906        Some(self.excerpt(excerpt_id)?.buffer_id)
6907    }
6908
6909    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6910        Some(&self.excerpt(excerpt_id)?.buffer)
6911    }
6912
6913    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6914        let mut cursor = self
6915            .excerpts
6916            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6917        let locator = self.excerpt_locator_for_id(excerpt_id);
6918        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6919        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6920            sought_exact = true;
6921            cursor.prev();
6922        } else if excerpt_id == ExcerptId::min() {
6923            sought_exact = true;
6924        }
6925        if sought_exact {
6926            let start = cursor.start().1;
6927            let end = cursor.end().1;
6928            let mut diff_transforms = self
6929                .diff_transforms
6930                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6931            diff_transforms.seek(&start, Bias::Left);
6932            let overshoot = start - diff_transforms.start().0;
6933            let start = diff_transforms.start().1 + overshoot;
6934            diff_transforms.seek(&end, Bias::Right);
6935            let overshoot = end - diff_transforms.start().0;
6936            let end = diff_transforms.start().1 + overshoot;
6937            Some(start.0..end.0)
6938        } else {
6939            None
6940        }
6941    }
6942
6943    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6944    /// to have the latest excerpt id for the one passed in and will also remap
6945    /// `ExcerptId::max()` to the corresponding excertp ID.
6946    ///
6947    /// Callers of this function should generally use the resulting excerpt's `id` field
6948    /// afterwards.
6949    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6950        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6951        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6952        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
6953        cursor.seek(&Some(locator), Bias::Left);
6954        if let Some(excerpt) = cursor.item()
6955            && excerpt.id == excerpt_id
6956        {
6957            return Some(excerpt);
6958        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6959            cursor.prev();
6960            return cursor.item();
6961        }
6962        None
6963    }
6964
6965    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6966    pub fn excerpt_containing<T: ToOffset>(
6967        &self,
6968        range: Range<T>,
6969    ) -> Option<MultiBufferExcerpt<'_>> {
6970        let range = range.start.to_offset(self)..range.end.to_offset(self);
6971        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6972        cursor.seek(&range.start);
6973
6974        let start_excerpt = cursor.excerpt()?;
6975        if range.end != range.start {
6976            cursor.seek_forward(&range.end);
6977            if cursor.excerpt()?.id != start_excerpt.id {
6978                return None;
6979            }
6980        }
6981
6982        cursor.seek_to_start_of_current_excerpt();
6983        let region = cursor.region()?;
6984        let offset = region.range.start;
6985        let buffer_offset = start_excerpt.buffer_start_offset();
6986        let excerpt_offset = *cursor.excerpts.start();
6987        Some(MultiBufferExcerpt {
6988            diff_transforms: cursor.diff_transforms,
6989            excerpt: start_excerpt,
6990            offset,
6991            buffer_offset,
6992            excerpt_offset,
6993        })
6994    }
6995
6996    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6997        if let Some(id) = anchor.text_anchor.buffer_id {
6998            return Some(id);
6999        }
7000        let excerpt = self.excerpt_containing(anchor..anchor)?;
7001        Some(excerpt.buffer_id())
7002    }
7003
7004    pub fn selections_in_range<'a>(
7005        &'a self,
7006        range: &'a Range<Anchor>,
7007        include_local: bool,
7008    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7009        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7010        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7011        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7012        cursor.seek(start_locator, Bias::Left);
7013        cursor
7014            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7015            .flat_map(move |excerpt| {
7016                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7017                if excerpt.id == range.start.excerpt_id {
7018                    query_range.start = range.start.text_anchor;
7019                }
7020                if excerpt.id == range.end.excerpt_id {
7021                    query_range.end = range.end.text_anchor;
7022                }
7023
7024                excerpt
7025                    .buffer
7026                    .selections_in_range(query_range, include_local)
7027                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7028                        selections.map(move |selection| {
7029                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7030                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7031                            if range.start.cmp(&start, self).is_gt() {
7032                                start = range.start;
7033                            }
7034                            if range.end.cmp(&end, self).is_lt() {
7035                                end = range.end;
7036                            }
7037
7038                            (
7039                                replica_id,
7040                                line_mode,
7041                                cursor_shape,
7042                                Selection {
7043                                    id: selection.id,
7044                                    start,
7045                                    end,
7046                                    reversed: selection.reversed,
7047                                    goal: selection.goal,
7048                                },
7049                            )
7050                        })
7051                    })
7052            })
7053    }
7054
7055    pub fn show_headers(&self) -> bool {
7056        self.show_headers
7057    }
7058
7059    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7060        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7061    }
7062
7063    pub fn all_diff_hunks_expanded(&self) -> bool {
7064        self.all_diff_hunks_expanded
7065    }
7066
7067    /// Visually annotates a position or range with the `Debug` representation of a value. The
7068    /// callsite of this function is used as a key - previous annotations will be removed.
7069    #[cfg(debug_assertions)]
7070    #[track_caller]
7071    pub fn debug<V, R>(&self, ranges: &R, value: V)
7072    where
7073        R: debug::ToMultiBufferDebugRanges,
7074        V: std::fmt::Debug,
7075    {
7076        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7077    }
7078
7079    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7080    /// debug annotations with the same key will be removed. The key is also used to determine the
7081    /// annotation's color.
7082    #[cfg(debug_assertions)]
7083    #[track_caller]
7084    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7085    where
7086        K: std::hash::Hash + 'static,
7087        R: debug::ToMultiBufferDebugRanges,
7088        V: std::fmt::Debug,
7089    {
7090        let text_ranges = ranges
7091            .to_multi_buffer_debug_ranges(self)
7092            .into_iter()
7093            .flat_map(|range| {
7094                self.range_to_buffer_ranges(range.start..=range.end)
7095                    .into_iter()
7096                    .map(|(buffer, range, _excerpt_id)| {
7097                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7098                    })
7099            })
7100            .collect();
7101        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7102            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7103        });
7104    }
7105
7106    fn excerpt_edits_for_diff_change(
7107        &self,
7108        buffer_state: &BufferState,
7109        diff_change_range: Range<usize>,
7110    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7111        let mut excerpt_edits = Vec::new();
7112        for locator in &buffer_state.excerpts {
7113            let mut cursor = self
7114                .excerpts
7115                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7116            cursor.seek_forward(&Some(locator), Bias::Left);
7117            if let Some(excerpt) = cursor.item()
7118                && excerpt.locator == *locator
7119            {
7120                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7121                if diff_change_range.end < excerpt_buffer_range.start
7122                    || diff_change_range.start > excerpt_buffer_range.end
7123                {
7124                    continue;
7125                }
7126                let excerpt_start = cursor.start().1;
7127                let excerpt_len = excerpt.text_summary.len;
7128                let diff_change_start_in_excerpt = diff_change_range
7129                    .start
7130                    .saturating_sub(excerpt_buffer_range.start);
7131                let diff_change_end_in_excerpt = diff_change_range
7132                    .end
7133                    .saturating_sub(excerpt_buffer_range.start);
7134                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7135                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7136                excerpt_edits.push(Edit {
7137                    old: edit_start..edit_end,
7138                    new: edit_start..edit_end,
7139                });
7140            }
7141        }
7142        excerpt_edits
7143    }
7144}
7145
7146#[cfg(any(test, feature = "test-support"))]
7147impl MultiBufferSnapshot {
7148    pub fn random_byte_range(
7149        &self,
7150        start_offset: MultiBufferOffset,
7151        rng: &mut impl rand::Rng,
7152    ) -> Range<MultiBufferOffset> {
7153        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7154        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7155        start..end
7156    }
7157
7158    #[cfg(any(test, feature = "test-support"))]
7159    fn check_invariants(&self) {
7160        let excerpts = self.excerpts.items(());
7161        let excerpt_ids = self.excerpt_ids.items(());
7162
7163        for (ix, excerpt) in excerpts.iter().enumerate() {
7164            if ix == 0 {
7165                if excerpt.locator <= Locator::min() {
7166                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7167                }
7168            } else if excerpt.locator <= excerpts[ix - 1].locator {
7169                panic!("excerpts are out-of-order: {:?}", excerpts);
7170            }
7171        }
7172
7173        for (ix, entry) in excerpt_ids.iter().enumerate() {
7174            if ix == 0 {
7175                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7176                    panic!("invalid first excerpt id {:?}", entry.id);
7177                }
7178            } else if entry.id <= excerpt_ids[ix - 1].id {
7179                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7180            }
7181        }
7182
7183        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7184            panic!(
7185                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7186                self.excerpts.summary().text,
7187                self.diff_transforms.summary().input,
7188                self.diff_transforms.items(()),
7189            );
7190        }
7191
7192        let mut prev_transform: Option<&DiffTransform> = None;
7193        for item in self.diff_transforms.iter() {
7194            if let DiffTransform::BufferContent {
7195                summary,
7196                inserted_hunk_info,
7197            } = item
7198            {
7199                if let Some(DiffTransform::BufferContent {
7200                    inserted_hunk_info: prev_inserted_hunk_info,
7201                    ..
7202                }) = prev_transform
7203                    && *inserted_hunk_info == *prev_inserted_hunk_info
7204                {
7205                    panic!(
7206                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7207                        self.diff_transforms.items(())
7208                    );
7209                }
7210                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7211                    panic!("empty buffer content transform");
7212                }
7213            }
7214            prev_transform = Some(item);
7215        }
7216    }
7217}
7218
7219impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7220where
7221    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7222    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7223{
7224    #[instrument(skip_all)]
7225    fn seek(&mut self, position: &MBD) {
7226        let position = OutputDimension(*position);
7227        self.cached_region.take();
7228        self.diff_transforms.seek(&position, Bias::Right);
7229        if self.diff_transforms.item().is_none()
7230            && self.diff_transforms.start().output_dimension == position
7231        {
7232            self.diff_transforms.prev();
7233        }
7234
7235        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7236        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7237            let overshoot = position - self.diff_transforms.start().output_dimension;
7238            excerpt_position += overshoot;
7239        }
7240
7241        self.excerpts.seek(&excerpt_position, Bias::Right);
7242        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7243            self.excerpts.prev();
7244        }
7245    }
7246
7247    fn seek_forward(&mut self, position: &MBD) {
7248        let position = OutputDimension(*position);
7249        self.cached_region.take();
7250        self.diff_transforms.seek_forward(&position, Bias::Right);
7251        if self.diff_transforms.item().is_none()
7252            && self.diff_transforms.start().output_dimension == position
7253        {
7254            self.diff_transforms.prev();
7255        }
7256
7257        let overshoot = position - self.diff_transforms.start().output_dimension;
7258        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7259        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7260            excerpt_position += overshoot;
7261        }
7262
7263        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7264        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7265            self.excerpts.prev();
7266        }
7267    }
7268
7269    fn next_excerpt(&mut self) {
7270        self.excerpts.next();
7271        self.seek_to_start_of_current_excerpt();
7272    }
7273
7274    fn prev_excerpt(&mut self) {
7275        self.excerpts.prev();
7276        self.seek_to_start_of_current_excerpt();
7277    }
7278
7279    fn seek_to_start_of_current_excerpt(&mut self) {
7280        self.cached_region.take();
7281
7282        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7283            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7284            && self.diff_transforms.next_item().is_some()
7285        {
7286            self.diff_transforms.next();
7287        }
7288    }
7289
7290    fn next_excerpt_forwards(&mut self) {
7291        self.excerpts.next();
7292        self.seek_to_start_of_current_excerpt_forward();
7293    }
7294
7295    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7296        self.cached_region.take();
7297
7298        if self
7299            .diff_transforms
7300            .seek_forward(self.excerpts.start(), Bias::Left)
7301            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7302            && self.diff_transforms.next_item().is_some()
7303        {
7304            self.diff_transforms.next();
7305        }
7306    }
7307
7308    fn next(&mut self) {
7309        self.cached_region.take();
7310        match self
7311            .diff_transforms
7312            .end()
7313            .excerpt_dimension
7314            .cmp(&self.excerpts.end())
7315        {
7316            cmp::Ordering::Less => self.diff_transforms.next(),
7317            cmp::Ordering::Greater => self.excerpts.next(),
7318            cmp::Ordering::Equal => {
7319                self.diff_transforms.next();
7320                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7321                    || self.diff_transforms.item().is_none()
7322                {
7323                    self.excerpts.next();
7324                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7325                    self.diff_transforms.item()
7326                    && self
7327                        .excerpts
7328                        .item()
7329                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7330                {
7331                    self.excerpts.next();
7332                }
7333            }
7334        }
7335    }
7336
7337    fn prev(&mut self) {
7338        self.cached_region.take();
7339        match self
7340            .diff_transforms
7341            .start()
7342            .excerpt_dimension
7343            .cmp(self.excerpts.start())
7344        {
7345            cmp::Ordering::Less => self.excerpts.prev(),
7346            cmp::Ordering::Greater => self.diff_transforms.prev(),
7347            cmp::Ordering::Equal => {
7348                self.diff_transforms.prev();
7349                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7350                    || self.diff_transforms.item().is_none()
7351                {
7352                    self.excerpts.prev();
7353                }
7354            }
7355        }
7356    }
7357
7358    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7359        self.cached_region
7360            .get_or_init(|| self.build_region())
7361            .as_ref()
7362    }
7363
7364    fn is_at_start_of_excerpt(&mut self) -> bool {
7365        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7366            return false;
7367        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7368            return true;
7369        }
7370
7371        self.diff_transforms.prev();
7372        let prev_transform = self.diff_transforms.item();
7373        self.diff_transforms.next();
7374
7375        prev_transform.is_none_or(|next_transform| {
7376            matches!(next_transform, DiffTransform::BufferContent { .. })
7377        })
7378    }
7379
7380    fn is_at_end_of_excerpt(&self) -> bool {
7381        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7382            return false;
7383        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7384            || self.diff_transforms.item().is_none()
7385        {
7386            return true;
7387        }
7388
7389        let next_transform = self.diff_transforms.next_item();
7390        next_transform.is_none_or(|next_transform| match next_transform {
7391            DiffTransform::BufferContent { .. } => true,
7392            DiffTransform::DeletedHunk { hunk_info, .. } => self
7393                .excerpts
7394                .item()
7395                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7396        })
7397    }
7398
7399    fn main_buffer_position(&self) -> Option<BD> {
7400        let excerpt = self.excerpts.item()?;
7401        let buffer = &excerpt.buffer;
7402        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7403        let mut buffer_start = buffer_context_start;
7404        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7405        buffer_start += overshoot;
7406        Some(buffer_start)
7407    }
7408
7409    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7410        let excerpt = self.excerpts.item()?;
7411        match self.diff_transforms.item()? {
7412            DiffTransform::DeletedHunk {
7413                buffer_id,
7414                base_text_byte_range,
7415                has_trailing_newline,
7416                hunk_info,
7417                ..
7418            } => {
7419                let diff = self.diffs.get(buffer_id)?;
7420                let buffer = diff.base_text();
7421                let mut rope_cursor = buffer.as_rope().cursor(0);
7422                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7423                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7424                let mut buffer_end = buffer_start;
7425                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7426                let start = self.diff_transforms.start().output_dimension.0;
7427                let end = self.diff_transforms.end().output_dimension.0;
7428                Some(MultiBufferRegion {
7429                    buffer,
7430                    excerpt,
7431                    has_trailing_newline: *has_trailing_newline,
7432                    is_main_buffer: false,
7433                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7434                        hunk_info.hunk_secondary_status,
7435                    )),
7436                    buffer_range: buffer_start..buffer_end,
7437                    range: start..end,
7438                })
7439            }
7440            DiffTransform::BufferContent {
7441                inserted_hunk_info, ..
7442            } => {
7443                let buffer = &excerpt.buffer;
7444                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7445
7446                let mut start = self.diff_transforms.start().output_dimension.0;
7447                let mut buffer_start = buffer_context_start;
7448                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7449                    let overshoot =
7450                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7451                    start += overshoot;
7452                } else {
7453                    let overshoot =
7454                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7455                    buffer_start += overshoot;
7456                }
7457
7458                let mut end;
7459                let mut buffer_end;
7460                let has_trailing_newline;
7461                let transform_end = self.diff_transforms.end();
7462                if transform_end.excerpt_dimension < self.excerpts.end() {
7463                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7464                    end = transform_end.output_dimension.0;
7465                    buffer_end = buffer_context_start;
7466                    buffer_end += overshoot;
7467                    has_trailing_newline = false;
7468                } else {
7469                    let overshoot =
7470                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7471                    end = self.diff_transforms.start().output_dimension.0;
7472                    end += overshoot;
7473                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7474                    has_trailing_newline = excerpt.has_trailing_newline;
7475                };
7476
7477                let diff_hunk_status = inserted_hunk_info.map(|info| {
7478                    if info.is_logically_deleted {
7479                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7480                    } else {
7481                        DiffHunkStatus::added(info.hunk_secondary_status)
7482                    }
7483                });
7484
7485                Some(MultiBufferRegion {
7486                    buffer,
7487                    excerpt,
7488                    has_trailing_newline,
7489                    is_main_buffer: true,
7490                    diff_hunk_status,
7491                    buffer_range: buffer_start..buffer_end,
7492                    range: start..end,
7493                })
7494            }
7495        }
7496    }
7497
7498    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7499        let excerpt = self.excerpts.item()?;
7500        match self.diff_transforms.item()? {
7501            &DiffTransform::DeletedHunk { .. } => {
7502                let start = self.diff_transforms.start().output_dimension.0;
7503                let end = self.diff_transforms.end().output_dimension.0;
7504                Some((excerpt, start..end))
7505            }
7506            DiffTransform::BufferContent { .. } => {
7507                let mut start = self.diff_transforms.start().output_dimension.0;
7508                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7509                    let overshoot =
7510                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7511                    start += overshoot;
7512                }
7513
7514                let mut end;
7515                let transform_end = self.diff_transforms.end();
7516                if transform_end.excerpt_dimension < self.excerpts.end() {
7517                    end = transform_end.output_dimension.0;
7518                } else {
7519                    let overshoot =
7520                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7521                    end = self.diff_transforms.start().output_dimension.0;
7522                    end += overshoot;
7523                };
7524
7525                Some((excerpt, start..end))
7526            }
7527        }
7528    }
7529
7530    fn excerpt(&self) -> Option<&'a Excerpt> {
7531        self.excerpts.item()
7532    }
7533}
7534
7535impl Excerpt {
7536    fn new(
7537        id: ExcerptId,
7538        locator: Locator,
7539        buffer_id: BufferId,
7540        buffer: Arc<BufferSnapshot>,
7541        range: ExcerptRange<text::Anchor>,
7542        has_trailing_newline: bool,
7543    ) -> Self {
7544        Excerpt {
7545            id,
7546            locator,
7547            max_buffer_row: range.context.end.to_point(&buffer).row,
7548            text_summary: buffer
7549                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7550            buffer_id,
7551            buffer,
7552            range,
7553            has_trailing_newline,
7554        }
7555    }
7556
7557    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7558        let content_start = self.range.context.start.to_offset(&self.buffer);
7559        let chunks_start = content_start + range.start;
7560        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7561
7562        let has_footer = self.has_trailing_newline
7563            && range.start <= self.text_summary.len
7564            && range.end > self.text_summary.len;
7565
7566        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7567
7568        ExcerptChunks {
7569            excerpt_id: self.id,
7570            content_chunks,
7571            has_footer,
7572        }
7573    }
7574
7575    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7576        let content_start = self.range.context.start.to_offset(&self.buffer);
7577        let chunks_start = content_start + range.start;
7578        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7579        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7580        excerpt_chunks.has_footer = self.has_trailing_newline
7581            && range.start <= self.text_summary.len
7582            && range.end > self.text_summary.len;
7583    }
7584
7585    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7586        if text_anchor
7587            .cmp(&self.range.context.start, &self.buffer)
7588            .is_lt()
7589        {
7590            self.range.context.start
7591        } else if text_anchor
7592            .cmp(&self.range.context.end, &self.buffer)
7593            .is_gt()
7594        {
7595            self.range.context.end
7596        } else {
7597            text_anchor
7598        }
7599    }
7600
7601    fn contains(&self, anchor: &Anchor) -> bool {
7602        (anchor.text_anchor.buffer_id == None
7603            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7604            && self
7605                .range
7606                .context
7607                .start
7608                .cmp(&anchor.text_anchor, &self.buffer)
7609                .is_le()
7610            && self
7611                .range
7612                .context
7613                .end
7614                .cmp(&anchor.text_anchor, &self.buffer)
7615                .is_ge()
7616    }
7617
7618    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7619    fn buffer_start_offset(&self) -> BufferOffset {
7620        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7621    }
7622
7623    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7624    fn buffer_end_offset(&self) -> BufferOffset {
7625        self.buffer_start_offset() + self.text_summary.len
7626    }
7627}
7628
7629impl<'a> MultiBufferExcerpt<'a> {
7630    pub fn id(&self) -> ExcerptId {
7631        self.excerpt.id
7632    }
7633
7634    pub fn buffer_id(&self) -> BufferId {
7635        self.excerpt.buffer_id
7636    }
7637
7638    pub fn start_anchor(&self) -> Anchor {
7639        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7640    }
7641
7642    pub fn end_anchor(&self) -> Anchor {
7643        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7644    }
7645
7646    pub fn buffer(&self) -> &'a BufferSnapshot {
7647        &self.excerpt.buffer
7648    }
7649
7650    pub fn buffer_range(&self) -> Range<BufferOffset> {
7651        self.buffer_offset
7652            ..BufferOffset(
7653                self.excerpt
7654                    .range
7655                    .context
7656                    .end
7657                    .to_offset(&self.excerpt.buffer.text),
7658            )
7659    }
7660
7661    pub fn start_offset(&self) -> MultiBufferOffset {
7662        self.offset
7663    }
7664
7665    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7666    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7667        self.map_range_to_buffer(offset..offset).start
7668    }
7669
7670    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7671    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7672        self.diff_transforms
7673            .seek(&OutputDimension(range.start), Bias::Right);
7674        let start = self.map_offset_to_buffer_internal(range.start);
7675        let end = if range.end > range.start {
7676            self.diff_transforms
7677                .seek_forward(&OutputDimension(range.end), Bias::Right);
7678            self.map_offset_to_buffer_internal(range.end)
7679        } else {
7680            start
7681        };
7682        start..end
7683    }
7684
7685    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7686        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7687        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7688            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7689        };
7690        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7691        self.buffer_offset + offset_in_excerpt
7692    }
7693
7694    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7695    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7696        self.map_range_from_buffer(buffer_offset..buffer_offset)
7697            .start
7698    }
7699
7700    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7701    pub fn map_range_from_buffer(
7702        &mut self,
7703        buffer_range: Range<BufferOffset>,
7704    ) -> Range<MultiBufferOffset> {
7705        if buffer_range.start < self.buffer_offset {
7706            log::warn!(
7707                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7708            );
7709            return self.offset..self.offset;
7710        }
7711        let overshoot = buffer_range.start - self.buffer_offset;
7712        let excerpt_offset = self.excerpt_offset + overshoot;
7713        let excerpt_seek_dim = excerpt_offset;
7714        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7715        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7716            log::warn!(
7717                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7718            );
7719            return self.offset..self.offset;
7720        }
7721        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7722        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7723
7724        let end = if buffer_range.start < buffer_range.end {
7725            let overshoot = buffer_range.end - self.buffer_offset;
7726            let excerpt_offset = self.excerpt_offset + overshoot;
7727            let excerpt_seek_dim = excerpt_offset;
7728            self.diff_transforms
7729                .seek_forward(&excerpt_seek_dim, Bias::Right);
7730            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7731            // todo(lw): Clamp end to the excerpt boundaries
7732            self.diff_transforms.start().output_dimension.0 + overshoot
7733        } else {
7734            start
7735        };
7736
7737        start..end
7738    }
7739
7740    /// Returns true if the entirety of the given range is in the buffer's excerpt
7741    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7742        range.start >= self.excerpt.buffer_start_offset()
7743            && range.end <= self.excerpt.buffer_end_offset()
7744    }
7745
7746    /// Returns true if any part of the given range is in the buffer's excerpt
7747    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7748        range.start <= self.excerpt.buffer_end_offset()
7749            && range.end >= self.excerpt.buffer_start_offset()
7750    }
7751
7752    pub fn max_buffer_row(&self) -> u32 {
7753        self.excerpt.max_buffer_row
7754    }
7755}
7756
7757impl ExcerptId {
7758    pub fn min() -> Self {
7759        Self(0)
7760    }
7761
7762    pub fn max() -> Self {
7763        Self(u32::MAX)
7764    }
7765
7766    pub fn to_proto(self) -> u64 {
7767        self.0 as _
7768    }
7769
7770    pub fn from_proto(proto: u64) -> Self {
7771        Self(proto as _)
7772    }
7773
7774    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7775        let a = snapshot.excerpt_locator_for_id(*self);
7776        let b = snapshot.excerpt_locator_for_id(*other);
7777        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7778    }
7779}
7780
7781impl From<ExcerptId> for usize {
7782    fn from(val: ExcerptId) -> Self {
7783        val.0 as usize
7784    }
7785}
7786
7787impl fmt::Debug for Excerpt {
7788    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7789        f.debug_struct("Excerpt")
7790            .field("id", &self.id)
7791            .field("locator", &self.locator)
7792            .field("buffer_id", &self.buffer_id)
7793            .field("range", &self.range)
7794            .field("text_summary", &self.text_summary)
7795            .field("has_trailing_newline", &self.has_trailing_newline)
7796            .finish()
7797    }
7798}
7799
7800impl sum_tree::Item for Excerpt {
7801    type Summary = ExcerptSummary;
7802
7803    fn summary(&self, _cx: ()) -> Self::Summary {
7804        let mut text = self.text_summary;
7805        if self.has_trailing_newline {
7806            text += TextSummary::from("\n");
7807        }
7808        ExcerptSummary {
7809            excerpt_id: self.id,
7810            excerpt_locator: self.locator.clone(),
7811            widest_line_number: self.max_buffer_row,
7812            text: text.into(),
7813            count: 1,
7814        }
7815    }
7816}
7817
7818impl sum_tree::Item for ExcerptIdMapping {
7819    type Summary = ExcerptId;
7820
7821    fn summary(&self, _cx: ()) -> Self::Summary {
7822        self.id
7823    }
7824}
7825
7826impl sum_tree::KeyedItem for ExcerptIdMapping {
7827    type Key = ExcerptId;
7828
7829    fn key(&self) -> Self::Key {
7830        self.id
7831    }
7832}
7833
7834impl DiffTransform {
7835    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7836        match self {
7837            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7838            DiffTransform::BufferContent {
7839                inserted_hunk_info, ..
7840            } => *inserted_hunk_info,
7841        }
7842    }
7843}
7844
7845impl sum_tree::Item for DiffTransform {
7846    type Summary = DiffTransformSummary;
7847
7848    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7849        match self {
7850            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7851                input: *summary,
7852                output: *summary,
7853            },
7854            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7855                input: MBTextSummary::default(),
7856                output: summary.into(),
7857            },
7858        }
7859    }
7860}
7861
7862impl DiffTransformSummary {
7863    fn excerpt_len(&self) -> ExcerptOffset {
7864        ExcerptDimension(self.input.len)
7865    }
7866}
7867
7868impl sum_tree::ContextLessSummary for DiffTransformSummary {
7869    fn zero() -> Self {
7870        DiffTransformSummary {
7871            input: MBTextSummary::default(),
7872            output: MBTextSummary::default(),
7873        }
7874    }
7875
7876    fn add_summary(&mut self, other: &Self) {
7877        self.input += other.input;
7878        self.output += other.output;
7879    }
7880}
7881
7882impl sum_tree::ContextLessSummary for ExcerptId {
7883    fn zero() -> Self {
7884        Self(0)
7885    }
7886
7887    fn add_summary(&mut self, summary: &Self) {
7888        *self = cmp::max(*self, *summary);
7889    }
7890}
7891
7892impl sum_tree::ContextLessSummary for ExcerptSummary {
7893    fn zero() -> Self {
7894        Self::default()
7895    }
7896
7897    fn add_summary(&mut self, summary: &Self) {
7898        debug_assert!(
7899            summary.excerpt_locator > self.excerpt_locator
7900                || self.excerpt_locator == Locator::min(),
7901            "Excerpt locators must be in ascending order: {:?} > {:?}",
7902            summary.excerpt_locator,
7903            self.excerpt_locator
7904        );
7905        self.excerpt_locator = summary.excerpt_locator.clone();
7906        self.text += summary.text;
7907        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7908        self.count += summary.count;
7909    }
7910}
7911
7912impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7913    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7914        Ord::cmp(&Some(self), cursor_location)
7915    }
7916}
7917
7918impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7919    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7920        Ord::cmp(self, &cursor_location.excerpt_locator)
7921    }
7922}
7923
7924impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7925where
7926    MBD: MultiBufferDimension + Default,
7927{
7928    fn zero(_: ()) -> Self {
7929        ExcerptDimension(MBD::default())
7930    }
7931
7932    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7933        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7934    }
7935}
7936
7937impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7938    fn zero(_cx: ()) -> Self {
7939        Default::default()
7940    }
7941
7942    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7943        *self = Some(&summary.excerpt_locator);
7944    }
7945}
7946
7947impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7948    fn zero(_cx: ()) -> Self {
7949        Default::default()
7950    }
7951
7952    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7953        *self = Some(summary.excerpt_id);
7954    }
7955}
7956
7957#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7958struct OutputDimension<T>(T);
7959
7960impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7961    fn eq(&self, other: &T) -> bool {
7962        self.0 == *other
7963    }
7964}
7965
7966impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7967    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7968        self.0.partial_cmp(other)
7969    }
7970}
7971
7972impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7973where
7974    T: ops::Sub<U, Output = R>,
7975{
7976    type Output = R;
7977
7978    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7979        self.0 - other.0
7980    }
7981}
7982
7983impl<R, T, U> ops::Add<U> for OutputDimension<T>
7984where
7985    T: ops::Add<U, Output = R>,
7986{
7987    type Output = OutputDimension<R>;
7988
7989    fn add(self, other: U) -> Self::Output {
7990        OutputDimension(self.0 + other)
7991    }
7992}
7993
7994impl<T, U> AddAssign<U> for OutputDimension<T>
7995where
7996    T: AddAssign<U>,
7997{
7998    fn add_assign(&mut self, other: U) {
7999        self.0 += other;
8000    }
8001}
8002
8003impl<T, U> SubAssign<U> for OutputDimension<T>
8004where
8005    T: SubAssign<U>,
8006{
8007    fn sub_assign(&mut self, other: U) {
8008        self.0 -= other;
8009    }
8010}
8011
8012#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8013struct ExcerptDimension<T>(T);
8014
8015impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8016    fn eq(&self, other: &T) -> bool {
8017        self.0 == *other
8018    }
8019}
8020
8021impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8022    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8023        self.0.partial_cmp(other)
8024    }
8025}
8026
8027impl ExcerptOffset {
8028    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8029        self.0.saturating_sub(other.0)
8030    }
8031}
8032
8033impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8034where
8035    T: ops::Sub<U, Output = R>,
8036{
8037    type Output = R;
8038
8039    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8040        self.0 - other.0
8041    }
8042}
8043
8044impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8045where
8046    T: ops::Add<U, Output = R>,
8047{
8048    type Output = ExcerptDimension<R>;
8049
8050    fn add(self, other: U) -> Self::Output {
8051        ExcerptDimension(self.0 + other)
8052    }
8053}
8054
8055impl<T, U> AddAssign<U> for ExcerptDimension<T>
8056where
8057    T: AddAssign<U>,
8058{
8059    fn add_assign(&mut self, other: U) {
8060        self.0 += other;
8061    }
8062}
8063
8064impl<T, U> SubAssign<U> for ExcerptDimension<T>
8065where
8066    T: SubAssign<U>,
8067{
8068    fn sub_assign(&mut self, other: U) {
8069        self.0 -= other;
8070    }
8071}
8072
8073impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8074    fn zero(_: ()) -> Self {
8075        MultiBufferOffset::ZERO
8076    }
8077
8078    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8079        *self += summary.output.len;
8080    }
8081}
8082
8083impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8084    for ExcerptDimension<MBD>
8085where
8086    MBD: MultiBufferDimension + Ord,
8087{
8088    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8089        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8090    }
8091}
8092
8093impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8094    for ExcerptDimension<MBD>
8095where
8096    MBD: MultiBufferDimension + Ord,
8097{
8098    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8099        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8100    }
8101}
8102
8103impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8104    for ExcerptDimension<MBD>
8105{
8106    fn zero(_: ()) -> Self {
8107        ExcerptDimension(MBD::default())
8108    }
8109
8110    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8111        self.0.add_mb_text_summary(&summary.input)
8112    }
8113}
8114
8115impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8116    for OutputDimension<MBD>
8117where
8118    MBD: MultiBufferDimension + Ord,
8119{
8120    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8121        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8122    }
8123}
8124
8125impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8126    for OutputDimension<MBD>
8127{
8128    fn zero(_: ()) -> Self {
8129        OutputDimension(MBD::default())
8130    }
8131
8132    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8133        self.0.add_mb_text_summary(&summary.output)
8134    }
8135}
8136
8137impl MultiBufferRows<'_> {
8138    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8139        self.point = Point::new(row, 0);
8140        self.cursor.seek(&self.point);
8141    }
8142}
8143
8144impl Iterator for MultiBufferRows<'_> {
8145    type Item = RowInfo;
8146
8147    fn next(&mut self) -> Option<Self::Item> {
8148        if self.is_empty && self.point.row == 0 {
8149            self.point += Point::new(1, 0);
8150            return Some(RowInfo {
8151                buffer_id: None,
8152                buffer_row: Some(0),
8153                multibuffer_row: Some(MultiBufferRow(0)),
8154                diff_status: None,
8155                expand_info: None,
8156                wrapped_buffer_row: None,
8157            });
8158        }
8159
8160        let mut region = self.cursor.region()?.clone();
8161        while self.point >= region.range.end {
8162            self.cursor.next();
8163            if let Some(next_region) = self.cursor.region() {
8164                region = next_region.clone();
8165            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8166                let multibuffer_row = MultiBufferRow(self.point.row);
8167                let last_excerpt = self
8168                    .cursor
8169                    .excerpts
8170                    .item()
8171                    .or(self.cursor.excerpts.prev_item())?;
8172                let last_row = last_excerpt
8173                    .range
8174                    .context
8175                    .end
8176                    .to_point(&last_excerpt.buffer)
8177                    .row;
8178
8179                let first_row = last_excerpt
8180                    .range
8181                    .context
8182                    .start
8183                    .to_point(&last_excerpt.buffer)
8184                    .row;
8185
8186                let expand_info = if self.is_singleton {
8187                    None
8188                } else {
8189                    let needs_expand_up = first_row == last_row
8190                        && last_row > 0
8191                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8192                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8193
8194                    if needs_expand_up && needs_expand_down {
8195                        Some(ExpandExcerptDirection::UpAndDown)
8196                    } else if needs_expand_up {
8197                        Some(ExpandExcerptDirection::Up)
8198                    } else if needs_expand_down {
8199                        Some(ExpandExcerptDirection::Down)
8200                    } else {
8201                        None
8202                    }
8203                    .map(|direction| ExpandInfo {
8204                        direction,
8205                        excerpt_id: last_excerpt.id,
8206                    })
8207                };
8208                self.point += Point::new(1, 0);
8209                return Some(RowInfo {
8210                    buffer_id: Some(last_excerpt.buffer_id),
8211                    buffer_row: Some(last_row),
8212                    multibuffer_row: Some(multibuffer_row),
8213                    diff_status: None,
8214                    wrapped_buffer_row: None,
8215                    expand_info,
8216                });
8217            } else {
8218                return None;
8219            };
8220        }
8221
8222        let overshoot = self.point - region.range.start;
8223        let buffer_point = region.buffer_range.start + overshoot;
8224        let expand_info = if self.is_singleton {
8225            None
8226        } else {
8227            let needs_expand_up = self.point.row == region.range.start.row
8228                && self.cursor.is_at_start_of_excerpt()
8229                && buffer_point.row > 0;
8230            let needs_expand_down = (region.excerpt.has_trailing_newline
8231                && self.point.row + 1 == region.range.end.row
8232                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8233                && self.cursor.is_at_end_of_excerpt()
8234                && buffer_point.row < region.buffer.max_point().row;
8235
8236            if needs_expand_up && needs_expand_down {
8237                Some(ExpandExcerptDirection::UpAndDown)
8238            } else if needs_expand_up {
8239                Some(ExpandExcerptDirection::Up)
8240            } else if needs_expand_down {
8241                Some(ExpandExcerptDirection::Down)
8242            } else {
8243                None
8244            }
8245            .map(|direction| ExpandInfo {
8246                direction,
8247                excerpt_id: region.excerpt.id,
8248            })
8249        };
8250
8251        let result = Some(RowInfo {
8252            buffer_id: Some(region.buffer.remote_id()),
8253            buffer_row: Some(buffer_point.row),
8254            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8255            diff_status: region
8256                .diff_hunk_status
8257                .filter(|_| self.point < region.range.end),
8258            expand_info,
8259            wrapped_buffer_row: None,
8260        });
8261        self.point += Point::new(1, 0);
8262        result
8263    }
8264}
8265
8266impl<'a> MultiBufferChunks<'a> {
8267    pub fn offset(&self) -> MultiBufferOffset {
8268        self.range.start
8269    }
8270
8271    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8272        self.diff_transforms.seek(&range.end, Bias::Right);
8273        let mut excerpt_end = self.diff_transforms.start().1;
8274        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8275            let overshoot = range.end - self.diff_transforms.start().0;
8276            excerpt_end += overshoot;
8277        }
8278
8279        self.diff_transforms.seek(&range.start, Bias::Right);
8280        let mut excerpt_start = self.diff_transforms.start().1;
8281        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8282            let overshoot = range.start - self.diff_transforms.start().0;
8283            excerpt_start += overshoot;
8284        }
8285
8286        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8287        self.buffer_chunk.take();
8288        self.range = range;
8289    }
8290
8291    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8292        self.excerpt_offset_range = new_range.clone();
8293        self.excerpts.seek(&new_range.start, Bias::Right);
8294        if let Some(excerpt) = self.excerpts.item() {
8295            let excerpt_start = *self.excerpts.start();
8296            if let Some(excerpt_chunks) = self
8297                .excerpt_chunks
8298                .as_mut()
8299                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8300            {
8301                excerpt.seek_chunks(
8302                    excerpt_chunks,
8303                    (self.excerpt_offset_range.start - excerpt_start)
8304                        ..(self.excerpt_offset_range.end - excerpt_start),
8305                );
8306            } else {
8307                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8308                    (self.excerpt_offset_range.start - excerpt_start)
8309                        ..(self.excerpt_offset_range.end - excerpt_start),
8310                    self.language_aware,
8311                ));
8312            }
8313        } else {
8314            self.excerpt_chunks = None;
8315        }
8316    }
8317
8318    #[ztracing::instrument(skip_all)]
8319    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8320        loop {
8321            if self.excerpt_offset_range.is_empty() {
8322                return None;
8323            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8324                self.excerpt_offset_range.start += chunk.text.len();
8325                return Some(chunk);
8326            } else {
8327                self.excerpts.next();
8328                let excerpt = self.excerpts.item()?;
8329                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8330                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8331                    self.language_aware,
8332                ));
8333            }
8334        }
8335    }
8336}
8337
8338impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8339    type Item = &'a str;
8340
8341    fn next(&mut self) -> Option<Self::Item> {
8342        let mut region = self.cursor.region()?;
8343        if self.offset == region.range.start {
8344            self.cursor.prev();
8345            region = self.cursor.region()?;
8346            let start_overshoot = self.start.saturating_sub(region.range.start);
8347            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8348                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8349            ));
8350        }
8351
8352        if self.offset == region.range.end && region.has_trailing_newline {
8353            self.offset -= 1;
8354            Some("\n")
8355        } else {
8356            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8357            self.offset -= chunk.len();
8358            Some(chunk)
8359        }
8360    }
8361}
8362
8363impl<'a> Iterator for MultiBufferChunks<'a> {
8364    type Item = Chunk<'a>;
8365
8366    #[ztracing::instrument(skip_all)]
8367    fn next(&mut self) -> Option<Chunk<'a>> {
8368        if self.range.start >= self.range.end {
8369            return None;
8370        }
8371        if self.range.start == self.diff_transforms.end().0 {
8372            self.diff_transforms.next();
8373        }
8374
8375        let diff_transform_start = self.diff_transforms.start().0;
8376        let diff_transform_end = self.diff_transforms.end().0;
8377        debug_assert!(
8378            self.range.start < diff_transform_end,
8379            "{:?} < {:?} of ({1:?}..{2:?})",
8380            self.range.start,
8381            diff_transform_end,
8382            diff_transform_start
8383        );
8384
8385        let diff_transform = self.diff_transforms.item()?;
8386        match diff_transform {
8387            DiffTransform::BufferContent { .. } => {
8388                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8389                    chunk
8390                } else {
8391                    let chunk = self.next_excerpt_chunk().unwrap();
8392                    self.buffer_chunk.insert(chunk)
8393                };
8394
8395                let chunk_end = self.range.start + chunk.text.len();
8396                let diff_transform_end = diff_transform_end.min(self.range.end);
8397
8398                if diff_transform_end < chunk_end {
8399                    let split_idx = diff_transform_end - self.range.start;
8400                    let (before, after) = chunk.text.split_at(split_idx);
8401                    self.range.start = diff_transform_end;
8402                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8403                    let chars = chunk.chars & mask;
8404                    let tabs = chunk.tabs & mask;
8405                    let newlines = chunk.newlines & mask;
8406
8407                    chunk.text = after;
8408                    chunk.chars = chunk.chars >> split_idx;
8409                    chunk.tabs = chunk.tabs >> split_idx;
8410                    chunk.newlines = chunk.newlines >> split_idx;
8411
8412                    Some(Chunk {
8413                        text: before,
8414                        chars,
8415                        tabs,
8416                        newlines,
8417                        ..chunk.clone()
8418                    })
8419                } else {
8420                    self.range.start = chunk_end;
8421                    self.buffer_chunk.take()
8422                }
8423            }
8424            DiffTransform::DeletedHunk {
8425                buffer_id,
8426                base_text_byte_range,
8427                has_trailing_newline,
8428                ..
8429            } => {
8430                let base_text_start =
8431                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8432                let base_text_end =
8433                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8434                let base_text_end = base_text_end.min(base_text_byte_range.end);
8435
8436                let mut chunks = if let Some((_, mut chunks)) = self
8437                    .diff_base_chunks
8438                    .take()
8439                    .filter(|(id, _)| id == buffer_id)
8440                {
8441                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8442                    {
8443                        chunks.seek(base_text_start..base_text_end);
8444                    }
8445                    chunks
8446                } else {
8447                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8448                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8449                };
8450
8451                let chunk = if let Some(chunk) = chunks.next() {
8452                    self.range.start += chunk.text.len();
8453                    self.diff_base_chunks = Some((*buffer_id, chunks));
8454                    chunk
8455                } else {
8456                    debug_assert!(has_trailing_newline);
8457                    self.range.start += "\n".len();
8458                    Chunk {
8459                        text: "\n",
8460                        chars: 1u128,
8461                        newlines: 1u128,
8462                        ..Default::default()
8463                    }
8464                };
8465                Some(chunk)
8466            }
8467        }
8468    }
8469}
8470
8471impl MultiBufferBytes<'_> {
8472    fn consume(&mut self, len: usize) {
8473        self.range.start += len;
8474        self.chunk = &self.chunk[len..];
8475
8476        if !self.range.is_empty() && self.chunk.is_empty() {
8477            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8478                self.chunk = chunk;
8479            } else if self.has_trailing_newline {
8480                self.has_trailing_newline = false;
8481                self.chunk = b"\n";
8482            } else {
8483                self.cursor.next();
8484                if let Some(region) = self.cursor.region() {
8485                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8486                        region.buffer_range.start
8487                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8488                                .min(region.buffer_range.end),
8489                    );
8490                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8491                    self.excerpt_bytes = Some(excerpt_bytes);
8492                    self.has_trailing_newline =
8493                        region.has_trailing_newline && self.range.end >= region.range.end;
8494                    if self.chunk.is_empty() && self.has_trailing_newline {
8495                        self.has_trailing_newline = false;
8496                        self.chunk = b"\n";
8497                    }
8498                }
8499            }
8500        }
8501    }
8502}
8503
8504impl<'a> Iterator for MultiBufferBytes<'a> {
8505    type Item = &'a [u8];
8506
8507    fn next(&mut self) -> Option<Self::Item> {
8508        let chunk = self.chunk;
8509        if chunk.is_empty() {
8510            None
8511        } else {
8512            self.consume(chunk.len());
8513            Some(chunk)
8514        }
8515    }
8516}
8517
8518impl io::Read for MultiBufferBytes<'_> {
8519    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8520        let len = cmp::min(buf.len(), self.chunk.len());
8521        buf[..len].copy_from_slice(&self.chunk[..len]);
8522        if len > 0 {
8523            self.consume(len);
8524        }
8525        Ok(len)
8526    }
8527}
8528
8529impl io::Read for ReversedMultiBufferBytes<'_> {
8530    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8531        let len = cmp::min(buf.len(), self.chunk.len());
8532        buf[..len].copy_from_slice(&self.chunk[..len]);
8533        buf[..len].reverse();
8534        if len > 0 {
8535            self.range.end -= len;
8536            self.chunk = &self.chunk[..self.chunk.len() - len];
8537            if !self.range.is_empty()
8538                && self.chunk.is_empty()
8539                && let Some(chunk) = self.chunks.next()
8540            {
8541                self.chunk = chunk.as_bytes();
8542            }
8543        }
8544        Ok(len)
8545    }
8546}
8547
8548impl<'a> Iterator for ExcerptChunks<'a> {
8549    type Item = Chunk<'a>;
8550
8551    fn next(&mut self) -> Option<Self::Item> {
8552        if let Some(chunk) = self.content_chunks.next() {
8553            return Some(chunk);
8554        }
8555
8556        if self.has_footer {
8557            let text = "\n";
8558            let chars = 0b1;
8559            let newlines = 0b1;
8560            self.has_footer = false;
8561            return Some(Chunk {
8562                text,
8563                chars,
8564                newlines,
8565                ..Default::default()
8566            });
8567        }
8568
8569        None
8570    }
8571}
8572
8573impl ToOffset for Point {
8574    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8575        snapshot.point_to_offset(*self)
8576    }
8577    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8578        snapshot.point_to_offset_utf16(*self)
8579    }
8580}
8581
8582impl ToOffset for MultiBufferOffset {
8583    #[track_caller]
8584    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8585        assert!(
8586            *self <= snapshot.len(),
8587            "offset {} is greater than the snapshot.len() {}",
8588            self.0,
8589            snapshot.len().0,
8590        );
8591        *self
8592    }
8593    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8594        snapshot.offset_to_offset_utf16(*self)
8595    }
8596}
8597
8598impl ToOffset for MultiBufferOffsetUtf16 {
8599    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8600        snapshot.offset_utf16_to_offset(*self)
8601    }
8602
8603    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8604        *self
8605    }
8606}
8607
8608impl ToOffset for PointUtf16 {
8609    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8610        snapshot.point_utf16_to_offset(*self)
8611    }
8612    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8613        snapshot.point_utf16_to_offset_utf16(*self)
8614    }
8615}
8616
8617impl ToPoint for MultiBufferOffset {
8618    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8619        snapshot.offset_to_point(*self)
8620    }
8621    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8622        snapshot.offset_to_point_utf16(*self)
8623    }
8624}
8625
8626impl ToPoint for Point {
8627    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8628        *self
8629    }
8630    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8631        snapshot.point_to_point_utf16(*self)
8632    }
8633}
8634
8635impl ToPoint for PointUtf16 {
8636    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8637        snapshot.point_utf16_to_point(*self)
8638    }
8639    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8640        *self
8641    }
8642}
8643
8644impl From<ExcerptId> for EntityId {
8645    fn from(id: ExcerptId) -> Self {
8646        EntityId::from(id.0 as u64)
8647    }
8648}
8649
8650#[cfg(debug_assertions)]
8651pub mod debug {
8652    use super::*;
8653
8654    pub trait ToMultiBufferDebugRanges {
8655        fn to_multi_buffer_debug_ranges(
8656            &self,
8657            snapshot: &MultiBufferSnapshot,
8658        ) -> Vec<Range<MultiBufferOffset>>;
8659    }
8660
8661    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8662        fn to_multi_buffer_debug_ranges(
8663            &self,
8664            snapshot: &MultiBufferSnapshot,
8665        ) -> Vec<Range<MultiBufferOffset>> {
8666            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8667        }
8668    }
8669
8670    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8671        fn to_multi_buffer_debug_ranges(
8672            &self,
8673            snapshot: &MultiBufferSnapshot,
8674        ) -> Vec<Range<MultiBufferOffset>> {
8675            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8676                .to_multi_buffer_debug_ranges(snapshot)
8677        }
8678    }
8679
8680    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8681        fn to_multi_buffer_debug_ranges(
8682            &self,
8683            snapshot: &MultiBufferSnapshot,
8684        ) -> Vec<Range<MultiBufferOffset>> {
8685            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8686        }
8687    }
8688
8689    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8690        fn to_multi_buffer_debug_ranges(
8691            &self,
8692            snapshot: &MultiBufferSnapshot,
8693        ) -> Vec<Range<MultiBufferOffset>> {
8694            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8695        }
8696    }
8697
8698    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8699        fn to_multi_buffer_debug_ranges(
8700            &self,
8701            snapshot: &MultiBufferSnapshot,
8702        ) -> Vec<Range<MultiBufferOffset>> {
8703            self.iter()
8704                .map(|item| {
8705                    let offset = item.to_offset(snapshot);
8706                    offset..offset
8707                })
8708                .collect()
8709        }
8710    }
8711
8712    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8713        fn to_multi_buffer_debug_ranges(
8714            &self,
8715            snapshot: &MultiBufferSnapshot,
8716        ) -> Vec<Range<MultiBufferOffset>> {
8717            self.iter()
8718                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8719                .collect()
8720        }
8721    }
8722}