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                            this.inverted_buffer_diff_changed(
 599                                diff,
 600                                main_buffer,
 601                                base_text_changed_range.clone(),
 602                                cx,
 603                            );
 604                            cx.emit(Event::BufferDiffChanged);
 605                        }
 606                        BufferDiffEvent::LanguageChanged => {
 607                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 608                        }
 609                        _ => {}
 610                    }
 611                }
 612            }),
 613            diff,
 614            main_buffer: Some(main_buffer),
 615        }
 616    }
 617}
 618
 619/// The contents of a [`MultiBuffer`] at a single point in time.
 620#[derive(Clone, Default)]
 621pub struct MultiBufferSnapshot {
 622    excerpts: SumTree<Excerpt>,
 623    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 624    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 625    diff_transforms: SumTree<DiffTransform>,
 626    excerpt_ids: SumTree<ExcerptIdMapping>,
 627    replaced_excerpts: Arc<HashMap<ExcerptId, ExcerptId>>,
 628    non_text_state_update_count: usize,
 629    edit_count: usize,
 630    is_dirty: bool,
 631    has_deleted_file: bool,
 632    has_conflict: bool,
 633    has_inverted_diff: bool,
 634    singleton: bool,
 635    trailing_excerpt_update_count: usize,
 636    all_diff_hunks_expanded: bool,
 637    show_deleted_hunks: bool,
 638    use_extended_diff_range: bool,
 639    show_headers: bool,
 640}
 641
 642// follower: None
 643// - BufferContent(Some)
 644// - BufferContent(None)
 645// - DeletedHunk
 646//
 647// follower: Some
 648// - BufferContent(Some)
 649// - BufferContent(None)
 650
 651#[derive(Debug, Clone)]
 652enum DiffTransform {
 653    // RealText
 654    BufferContent {
 655        summary: MBTextSummary,
 656        // modified_hunk_info
 657        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 658    },
 659    // ExpandedHunkText
 660    DeletedHunk {
 661        summary: TextSummary,
 662        buffer_id: BufferId,
 663        hunk_info: DiffTransformHunkInfo,
 664        base_text_byte_range: Range<usize>,
 665        has_trailing_newline: bool,
 666    },
 667}
 668
 669#[derive(Clone, Copy, Debug)]
 670struct DiffTransformHunkInfo {
 671    excerpt_id: ExcerptId,
 672    hunk_start_anchor: text::Anchor,
 673    hunk_secondary_status: DiffHunkSecondaryStatus,
 674    is_logically_deleted: bool,
 675}
 676
 677impl Eq for DiffTransformHunkInfo {}
 678
 679impl PartialEq for DiffTransformHunkInfo {
 680    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 681        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 682    }
 683}
 684
 685impl std::hash::Hash for DiffTransformHunkInfo {
 686    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 687        self.excerpt_id.hash(state);
 688        self.hunk_start_anchor.hash(state);
 689    }
 690}
 691
 692#[derive(Clone)]
 693pub struct ExcerptInfo {
 694    pub id: ExcerptId,
 695    pub buffer: Arc<BufferSnapshot>,
 696    pub buffer_id: BufferId,
 697    pub range: ExcerptRange<text::Anchor>,
 698    pub end_row: MultiBufferRow,
 699}
 700
 701impl std::fmt::Debug for ExcerptInfo {
 702    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 703        f.debug_struct(type_name::<Self>())
 704            .field("id", &self.id)
 705            .field("buffer_id", &self.buffer_id)
 706            .field("path", &self.buffer.file().map(|f| f.path()))
 707            .field("range", &self.range)
 708            .finish()
 709    }
 710}
 711
 712/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 713#[derive(Debug)]
 714pub struct ExcerptBoundary {
 715    pub prev: Option<ExcerptInfo>,
 716    pub next: ExcerptInfo,
 717    /// The row in the `MultiBuffer` where the boundary is located
 718    pub row: MultiBufferRow,
 719}
 720
 721impl ExcerptBoundary {
 722    pub fn starts_new_buffer(&self) -> bool {
 723        match (self.prev.as_ref(), &self.next) {
 724            (None, _) => true,
 725            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 726        }
 727    }
 728}
 729
 730#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 731pub struct ExpandInfo {
 732    pub direction: ExpandExcerptDirection,
 733    pub excerpt_id: ExcerptId,
 734}
 735
 736#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 737pub struct RowInfo {
 738    pub buffer_id: Option<BufferId>,
 739    pub buffer_row: Option<u32>,
 740    pub multibuffer_row: Option<MultiBufferRow>,
 741    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 742    pub expand_info: Option<ExpandInfo>,
 743    pub wrapped_buffer_row: Option<u32>,
 744}
 745
 746/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 747#[derive(Clone)]
 748struct Excerpt {
 749    /// The unique identifier for this excerpt
 750    id: ExcerptId,
 751    /// The location of the excerpt in the [`MultiBuffer`]
 752    locator: Locator,
 753    /// The buffer being excerpted
 754    buffer_id: BufferId,
 755    /// A snapshot of the buffer being excerpted
 756    buffer: Arc<BufferSnapshot>,
 757    /// The range of the buffer to be shown in the excerpt
 758    range: ExcerptRange<text::Anchor>,
 759    /// The last row in the excerpted slice of the buffer
 760    max_buffer_row: BufferRow,
 761    /// A summary of the text in the excerpt
 762    text_summary: TextSummary,
 763    has_trailing_newline: bool,
 764}
 765
 766/// A public view into an `Excerpt` in a [`MultiBuffer`].
 767///
 768/// Contains methods for getting the [`Buffer`] of the excerpt,
 769/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 770#[derive(Clone)]
 771pub struct MultiBufferExcerpt<'a> {
 772    excerpt: &'a Excerpt,
 773    diff_transforms:
 774        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 775    /// The offset in the multibuffer considering diff transforms.
 776    offset: MultiBufferOffset,
 777    /// The offset in the multibuffer without diff transforms.
 778    excerpt_offset: ExcerptOffset,
 779    buffer_offset: BufferOffset,
 780}
 781
 782#[derive(Clone, Debug)]
 783struct ExcerptIdMapping {
 784    id: ExcerptId,
 785    locator: Locator,
 786}
 787
 788/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 789/// These ranges are relative to the buffer itself
 790#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 791pub struct ExcerptRange<T> {
 792    /// The full range of text to be shown in the excerpt.
 793    pub context: Range<T>,
 794    /// The primary range of text to be highlighted in the excerpt.
 795    /// In a multi-buffer search, this would be the text that matched the search
 796    pub primary: Range<T>,
 797}
 798
 799impl<T: Clone> ExcerptRange<T> {
 800    pub fn new(context: Range<T>) -> Self {
 801        Self {
 802            context: context.clone(),
 803            primary: context,
 804        }
 805    }
 806}
 807
 808#[derive(Clone, Debug, Default)]
 809pub struct ExcerptSummary {
 810    excerpt_id: ExcerptId,
 811    /// The location of the last [`Excerpt`] being summarized
 812    excerpt_locator: Locator,
 813    widest_line_number: u32,
 814    text: MBTextSummary,
 815    count: usize,
 816}
 817
 818#[derive(Debug, Clone)]
 819pub struct DiffTransformSummary {
 820    input: MBTextSummary,
 821    output: MBTextSummary,
 822}
 823
 824/// Summary of a string of text.
 825#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 826pub struct MBTextSummary {
 827    /// Length in bytes.
 828    pub len: MultiBufferOffset,
 829    /// Length in UTF-8.
 830    pub chars: usize,
 831    /// Length in UTF-16 code units
 832    pub len_utf16: OffsetUtf16,
 833    /// A point representing the number of lines and the length of the last line.
 834    ///
 835    /// In other words, it marks the point after the last byte in the text, (if
 836    /// EOF was a character, this would be its position).
 837    pub lines: Point,
 838    /// How many `char`s are in the first line
 839    pub first_line_chars: u32,
 840    /// How many `char`s are in the last line
 841    pub last_line_chars: u32,
 842    /// How many UTF-16 code units are in the last line
 843    pub last_line_len_utf16: u32,
 844    /// The row idx of the longest row
 845    pub longest_row: u32,
 846    /// How many `char`s are in the longest row
 847    pub longest_row_chars: u32,
 848}
 849
 850impl From<TextSummary> for MBTextSummary {
 851    fn from(summary: TextSummary) -> Self {
 852        MBTextSummary {
 853            len: MultiBufferOffset(summary.len),
 854            chars: summary.chars,
 855            len_utf16: summary.len_utf16,
 856            lines: summary.lines,
 857            first_line_chars: summary.first_line_chars,
 858            last_line_chars: summary.last_line_chars,
 859            last_line_len_utf16: summary.last_line_len_utf16,
 860            longest_row: summary.longest_row,
 861            longest_row_chars: summary.longest_row_chars,
 862        }
 863    }
 864}
 865
 866impl From<MBTextSummary> for TextSummary {
 867    fn from(summary: MBTextSummary) -> Self {
 868        TextSummary {
 869            len: summary.len.0,
 870            chars: summary.chars,
 871            len_utf16: summary.len_utf16,
 872            lines: summary.lines,
 873            first_line_chars: summary.first_line_chars,
 874            last_line_chars: summary.last_line_chars,
 875            last_line_len_utf16: summary.last_line_len_utf16,
 876            longest_row: summary.longest_row,
 877            longest_row_chars: summary.longest_row_chars,
 878        }
 879    }
 880}
 881
 882impl From<&str> for MBTextSummary {
 883    fn from(text: &str) -> Self {
 884        MBTextSummary::from(TextSummary::from(text))
 885    }
 886}
 887
 888impl MultiBufferDimension for MBTextSummary {
 889    type TextDimension = TextSummary;
 890
 891    fn from_summary(summary: &MBTextSummary) -> Self {
 892        *summary
 893    }
 894
 895    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 896        *self += *summary;
 897    }
 898
 899    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 900        *self += *summary;
 901    }
 902}
 903
 904impl AddAssign for MBTextSummary {
 905    fn add_assign(&mut self, other: MBTextSummary) {
 906        let joined_chars = self.last_line_chars + other.first_line_chars;
 907        if joined_chars > self.longest_row_chars {
 908            self.longest_row = self.lines.row;
 909            self.longest_row_chars = joined_chars;
 910        }
 911        if other.longest_row_chars > self.longest_row_chars {
 912            self.longest_row = self.lines.row + other.longest_row;
 913            self.longest_row_chars = other.longest_row_chars;
 914        }
 915
 916        if self.lines.row == 0 {
 917            self.first_line_chars += other.first_line_chars;
 918        }
 919
 920        if other.lines.row == 0 {
 921            self.last_line_chars += other.first_line_chars;
 922            self.last_line_len_utf16 += other.last_line_len_utf16;
 923        } else {
 924            self.last_line_chars = other.last_line_chars;
 925            self.last_line_len_utf16 = other.last_line_len_utf16;
 926        }
 927
 928        self.chars += other.chars;
 929        self.len += other.len;
 930        self.len_utf16 += other.len_utf16;
 931        self.lines += other.lines;
 932    }
 933}
 934
 935impl AddAssign<TextSummary> for MBTextSummary {
 936    fn add_assign(&mut self, other: TextSummary) {
 937        *self += MBTextSummary::from(other);
 938    }
 939}
 940
 941impl MBTextSummary {
 942    pub fn lines_utf16(&self) -> PointUtf16 {
 943        PointUtf16 {
 944            row: self.lines.row,
 945            column: self.last_line_len_utf16,
 946        }
 947    }
 948}
 949
 950impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 951where
 952    K: MultiBufferDimension,
 953    V: MultiBufferDimension,
 954{
 955    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 956
 957    fn from_summary(summary: &MBTextSummary) -> Self {
 958        Self {
 959            key: K::from_summary(summary),
 960            value: Some(V::from_summary(summary)),
 961        }
 962    }
 963
 964    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 965        self.key.add_text_dim(&summary.key);
 966        if let Some(value) = &mut self.value {
 967            if let Some(other_value) = summary.value.as_ref() {
 968                value.add_text_dim(other_value);
 969            }
 970        }
 971    }
 972
 973    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 974        self.key.add_mb_text_summary(summary);
 975        if let Some(value) = &mut self.value {
 976            value.add_mb_text_summary(summary);
 977        }
 978    }
 979}
 980
 981#[derive(Clone)]
 982pub struct MultiBufferRows<'a> {
 983    point: Point,
 984    is_empty: bool,
 985    is_singleton: bool,
 986    cursor: MultiBufferCursor<'a, Point, Point>,
 987}
 988
 989pub struct MultiBufferChunks<'a> {
 990    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 991    diff_transforms:
 992        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 993    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 994    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 995    buffer_chunk: Option<Chunk<'a>>,
 996    range: Range<MultiBufferOffset>,
 997    excerpt_offset_range: Range<ExcerptOffset>,
 998    excerpt_chunks: Option<ExcerptChunks<'a>>,
 999    language_aware: bool,
1000}
1001
1002pub struct ReversedMultiBufferChunks<'a> {
1003    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1004    current_chunks: Option<rope::Chunks<'a>>,
1005    start: MultiBufferOffset,
1006    offset: MultiBufferOffset,
1007}
1008
1009pub struct MultiBufferBytes<'a> {
1010    range: Range<MultiBufferOffset>,
1011    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1012    excerpt_bytes: Option<text::Bytes<'a>>,
1013    has_trailing_newline: bool,
1014    chunk: &'a [u8],
1015}
1016
1017pub struct ReversedMultiBufferBytes<'a> {
1018    range: Range<MultiBufferOffset>,
1019    chunks: ReversedMultiBufferChunks<'a>,
1020    chunk: &'a [u8],
1021}
1022
1023#[derive(Clone)]
1024struct DiffTransforms<MBD> {
1025    output_dimension: OutputDimension<MBD>,
1026    excerpt_dimension: ExcerptDimension<MBD>,
1027}
1028
1029impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1030    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1031        Self {
1032            output_dimension: OutputDimension::zero(cx),
1033            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1034                cx,
1035            ),
1036        }
1037    }
1038
1039    fn add_summary(
1040        &mut self,
1041        summary: &'a DiffTransformSummary,
1042        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1043    ) {
1044        self.output_dimension.add_summary(summary, cx);
1045        self.excerpt_dimension.add_summary(summary, cx);
1046    }
1047}
1048
1049#[derive(Clone)]
1050struct MultiBufferCursor<'a, MBD, BD> {
1051    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1052    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1053    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1054    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1055}
1056
1057#[derive(Clone)]
1058struct MultiBufferRegion<'a, MBD, BD> {
1059    buffer: &'a BufferSnapshot,
1060    is_main_buffer: bool,
1061    diff_hunk_status: Option<DiffHunkStatus>,
1062    excerpt: &'a Excerpt,
1063    buffer_range: Range<BD>,
1064    range: Range<MBD>,
1065    has_trailing_newline: bool,
1066}
1067
1068struct ExcerptChunks<'a> {
1069    excerpt_id: ExcerptId,
1070    content_chunks: BufferChunks<'a>,
1071    has_footer: bool,
1072}
1073
1074#[derive(Debug)]
1075struct BufferEdit {
1076    range: Range<BufferOffset>,
1077    new_text: Arc<str>,
1078    is_insertion: bool,
1079    original_indent_column: Option<u32>,
1080    excerpt_id: ExcerptId,
1081}
1082
1083#[derive(Clone, Copy, Debug, PartialEq)]
1084enum DiffChangeKind {
1085    BufferEdited,
1086    DiffUpdated { base_changed: bool },
1087    ExpandOrCollapseHunks { expand: bool },
1088}
1089
1090#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1091pub enum ExpandExcerptDirection {
1092    Up,
1093    Down,
1094    UpAndDown,
1095}
1096
1097impl ExpandExcerptDirection {
1098    pub fn should_expand_up(&self) -> bool {
1099        match self {
1100            ExpandExcerptDirection::Up => true,
1101            ExpandExcerptDirection::Down => false,
1102            ExpandExcerptDirection::UpAndDown => true,
1103        }
1104    }
1105
1106    pub fn should_expand_down(&self) -> bool {
1107        match self {
1108            ExpandExcerptDirection::Up => false,
1109            ExpandExcerptDirection::Down => true,
1110            ExpandExcerptDirection::UpAndDown => true,
1111        }
1112    }
1113}
1114
1115#[derive(Clone, Debug, PartialEq)]
1116pub struct IndentGuide {
1117    pub buffer_id: BufferId,
1118    pub start_row: MultiBufferRow,
1119    pub end_row: MultiBufferRow,
1120    pub depth: u32,
1121    pub tab_size: u32,
1122    pub settings: IndentGuideSettings,
1123}
1124
1125impl IndentGuide {
1126    pub fn indent_level(&self) -> u32 {
1127        self.depth * self.tab_size
1128    }
1129}
1130
1131impl MultiBuffer {
1132    pub fn new(capability: Capability) -> Self {
1133        Self::new_(
1134            capability,
1135            MultiBufferSnapshot {
1136                show_headers: true,
1137                show_deleted_hunks: true,
1138                ..MultiBufferSnapshot::default()
1139            },
1140        )
1141    }
1142
1143    pub fn without_headers(capability: Capability) -> Self {
1144        Self::new_(
1145            capability,
1146            MultiBufferSnapshot {
1147                show_deleted_hunks: true,
1148                ..MultiBufferSnapshot::default()
1149            },
1150        )
1151    }
1152
1153    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1154        let mut this = Self::new_(
1155            buffer.read(cx).capability(),
1156            MultiBufferSnapshot {
1157                singleton: true,
1158                show_deleted_hunks: true,
1159                ..MultiBufferSnapshot::default()
1160            },
1161        );
1162        this.singleton = true;
1163        this.set_excerpts_for_path(
1164            PathKey::sorted(0),
1165            buffer.clone(),
1166            [Point::zero()..buffer.read(cx).max_point()],
1167            0,
1168            cx,
1169        );
1170        this
1171    }
1172
1173    #[inline]
1174    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1175        Self {
1176            snapshot: RefCell::new(snapshot),
1177            buffers: Default::default(),
1178            diffs: HashMap::default(),
1179            subscriptions: Topic::default(),
1180            singleton: false,
1181            capability,
1182            title: None,
1183            excerpts_by_path: Default::default(),
1184            paths_by_excerpt: Default::default(),
1185            buffer_changed_since_sync: Default::default(),
1186            history: History::default(),
1187        }
1188    }
1189
1190    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1191        let mut buffers = BTreeMap::default();
1192        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1193        for (buffer_id, buffer_state) in self.buffers.iter() {
1194            buffer_state.buffer.update(new_cx, |buffer, _| {
1195                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1196            });
1197            buffers.insert(
1198                *buffer_id,
1199                BufferState {
1200                    buffer: buffer_state.buffer.clone(),
1201                    last_version: buffer_state.last_version.clone(),
1202                    last_non_text_state_update_count: buffer_state
1203                        .last_non_text_state_update_count
1204                        .clone(),
1205                    excerpts: buffer_state.excerpts.clone(),
1206                    _subscriptions: [
1207                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1208                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1209                    ],
1210                },
1211            );
1212        }
1213        let mut diff_bases = HashMap::default();
1214        for (buffer_id, diff) in self.diffs.iter() {
1215            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1216        }
1217        Self {
1218            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1219            buffers,
1220            excerpts_by_path: Default::default(),
1221            paths_by_excerpt: Default::default(),
1222            diffs: diff_bases,
1223            subscriptions: Default::default(),
1224            singleton: self.singleton,
1225            capability: self.capability,
1226            history: self.history.clone(),
1227            title: self.title.clone(),
1228            buffer_changed_since_sync,
1229        }
1230    }
1231
1232    pub fn set_group_interval(&mut self, group_interval: Duration) {
1233        self.history.set_group_interval(group_interval);
1234    }
1235
1236    pub fn with_title(mut self, title: String) -> Self {
1237        self.title = Some(title);
1238        self
1239    }
1240
1241    pub fn read_only(&self) -> bool {
1242        !self.capability.editable()
1243    }
1244
1245    pub fn capability(&self) -> Capability {
1246        self.capability
1247    }
1248
1249    /// Returns an up-to-date snapshot of the MultiBuffer.
1250    #[ztracing::instrument(skip_all)]
1251    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1252        self.sync(cx);
1253        self.snapshot.borrow().clone()
1254    }
1255
1256    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1257        self.sync(cx);
1258        self.snapshot.borrow()
1259    }
1260
1261    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1262        if self.singleton {
1263            Some(self.buffers.values().next().unwrap().buffer.clone())
1264        } else {
1265            None
1266        }
1267    }
1268
1269    pub fn is_singleton(&self) -> bool {
1270        self.singleton
1271    }
1272
1273    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1274        self.subscriptions.subscribe()
1275    }
1276
1277    pub fn is_dirty(&self, cx: &App) -> bool {
1278        self.read(cx).is_dirty()
1279    }
1280
1281    pub fn has_deleted_file(&self, cx: &App) -> bool {
1282        self.read(cx).has_deleted_file()
1283    }
1284
1285    pub fn has_conflict(&self, cx: &App) -> bool {
1286        self.read(cx).has_conflict()
1287    }
1288
1289    // The `is_empty` signature doesn't match what clippy expects
1290    #[allow(clippy::len_without_is_empty)]
1291    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1292        self.read(cx).len()
1293    }
1294
1295    pub fn is_empty(&self) -> bool {
1296        self.buffers.is_empty()
1297    }
1298
1299    pub fn edit<I, S, T>(
1300        &mut self,
1301        edits: I,
1302        autoindent_mode: Option<AutoindentMode>,
1303        cx: &mut Context<Self>,
1304    ) where
1305        I: IntoIterator<Item = (Range<S>, T)>,
1306        S: ToOffset,
1307        T: Into<Arc<str>>,
1308    {
1309        self.edit_internal(edits, autoindent_mode, true, cx);
1310    }
1311
1312    pub fn edit_non_coalesce<I, S, T>(
1313        &mut self,
1314        edits: I,
1315        autoindent_mode: Option<AutoindentMode>,
1316        cx: &mut Context<Self>,
1317    ) where
1318        I: IntoIterator<Item = (Range<S>, T)>,
1319        S: ToOffset,
1320        T: Into<Arc<str>>,
1321    {
1322        self.edit_internal(edits, autoindent_mode, false, cx);
1323    }
1324
1325    fn edit_internal<I, S, T>(
1326        &mut self,
1327        edits: I,
1328        autoindent_mode: Option<AutoindentMode>,
1329        coalesce_adjacent: bool,
1330        cx: &mut Context<Self>,
1331    ) where
1332        I: IntoIterator<Item = (Range<S>, T)>,
1333        S: ToOffset,
1334        T: Into<Arc<str>>,
1335    {
1336        if self.read_only() || self.buffers.is_empty() {
1337            return;
1338        }
1339        self.sync_mut(cx);
1340        let edits = edits
1341            .into_iter()
1342            .map(|(range, new_text)| {
1343                let mut range = range.start.to_offset(self.snapshot.get_mut())
1344                    ..range.end.to_offset(self.snapshot.get_mut());
1345                if range.start > range.end {
1346                    mem::swap(&mut range.start, &mut range.end);
1347                }
1348                (range, new_text.into())
1349            })
1350            .collect::<Vec<_>>();
1351
1352        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1353
1354        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1355        fn edit_internal(
1356            this: &mut MultiBuffer,
1357            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1358            mut autoindent_mode: Option<AutoindentMode>,
1359            coalesce_adjacent: bool,
1360            cx: &mut Context<MultiBuffer>,
1361        ) {
1362            let original_indent_columns = match &mut autoindent_mode {
1363                Some(AutoindentMode::Block {
1364                    original_indent_columns,
1365                }) => mem::take(original_indent_columns),
1366                _ => Default::default(),
1367            };
1368
1369            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1370                edits,
1371                this.snapshot.get_mut(),
1372                &original_indent_columns,
1373            );
1374
1375            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1376            for (buffer_id, mut edits) in buffer_edits {
1377                buffer_ids.push(buffer_id);
1378                edits.sort_by_key(|edit| edit.range.start);
1379                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1380                    let mut edits = edits.into_iter().peekable();
1381                    let mut insertions = Vec::new();
1382                    let mut original_indent_columns = Vec::new();
1383                    let mut deletions = Vec::new();
1384                    let empty_str: Arc<str> = Arc::default();
1385                    while let Some(BufferEdit {
1386                        mut range,
1387                        mut new_text,
1388                        mut is_insertion,
1389                        original_indent_column,
1390                        excerpt_id,
1391                    }) = edits.next()
1392                    {
1393                        while let Some(BufferEdit {
1394                            range: next_range,
1395                            is_insertion: next_is_insertion,
1396                            new_text: next_new_text,
1397                            excerpt_id: next_excerpt_id,
1398                            ..
1399                        }) = edits.peek()
1400                        {
1401                            let should_coalesce = if coalesce_adjacent {
1402                                range.end >= next_range.start
1403                            } else {
1404                                range.end > next_range.start
1405                            };
1406
1407                            if should_coalesce {
1408                                range.end = cmp::max(next_range.end, range.end);
1409                                is_insertion |= *next_is_insertion;
1410                                if excerpt_id == *next_excerpt_id {
1411                                    new_text = format!("{new_text}{next_new_text}").into();
1412                                }
1413                                edits.next();
1414                            } else {
1415                                break;
1416                            }
1417                        }
1418
1419                        if is_insertion {
1420                            original_indent_columns.push(original_indent_column);
1421                            insertions.push((
1422                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1423                                new_text.clone(),
1424                            ));
1425                        } else if !range.is_empty() {
1426                            deletions.push((
1427                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1428                                empty_str.clone(),
1429                            ));
1430                        }
1431                    }
1432
1433                    let deletion_autoindent_mode =
1434                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1435                            Some(AutoindentMode::Block {
1436                                original_indent_columns: Default::default(),
1437                            })
1438                        } else {
1439                            autoindent_mode.clone()
1440                        };
1441                    let insertion_autoindent_mode =
1442                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1443                            Some(AutoindentMode::Block {
1444                                original_indent_columns,
1445                            })
1446                        } else {
1447                            autoindent_mode.clone()
1448                        };
1449
1450                    if coalesce_adjacent {
1451                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1452                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1453                    } else {
1454                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1455                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1456                    }
1457                })
1458            }
1459
1460            cx.emit(Event::ExcerptsEdited {
1461                excerpt_ids: edited_excerpt_ids,
1462                buffer_ids,
1463            });
1464        }
1465    }
1466
1467    fn convert_edits_to_buffer_edits(
1468        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1469        snapshot: &MultiBufferSnapshot,
1470        original_indent_columns: &[Option<u32>],
1471    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1472        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1473        let mut edited_excerpt_ids = Vec::new();
1474        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1475        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1476            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1477
1478            cursor.seek(&range.start);
1479            let mut start_region = cursor.region().expect("start offset out of bounds");
1480            if !start_region.is_main_buffer {
1481                cursor.next();
1482                if let Some(region) = cursor.region() {
1483                    start_region = region;
1484                } else {
1485                    continue;
1486                }
1487            }
1488
1489            if range.end < start_region.range.start {
1490                continue;
1491            }
1492
1493            let start_region = start_region.clone();
1494            if range.end > start_region.range.end {
1495                cursor.seek_forward(&range.end);
1496            }
1497            let mut end_region = cursor.region().expect("end offset out of bounds");
1498            if !end_region.is_main_buffer {
1499                cursor.prev();
1500                if let Some(region) = cursor.region() {
1501                    end_region = region;
1502                } else {
1503                    continue;
1504                }
1505            }
1506
1507            if range.start > end_region.range.end {
1508                continue;
1509            }
1510
1511            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1512            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1513            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1514                .min(start_region.buffer_range.end);
1515            let buffer_end =
1516                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1517
1518            if start_region.excerpt.id == end_region.excerpt.id {
1519                if start_region.buffer.capability == Capability::ReadWrite
1520                    && start_region.is_main_buffer
1521                {
1522                    edited_excerpt_ids.push(start_region.excerpt.id);
1523                    buffer_edits
1524                        .entry(start_region.buffer.remote_id())
1525                        .or_default()
1526                        .push(BufferEdit {
1527                            range: buffer_start..buffer_end,
1528                            new_text,
1529                            is_insertion: true,
1530                            original_indent_column,
1531                            excerpt_id: start_region.excerpt.id,
1532                        });
1533                }
1534            } else {
1535                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1536                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1537                if start_region.buffer.capability == Capability::ReadWrite
1538                    && start_region.is_main_buffer
1539                {
1540                    edited_excerpt_ids.push(start_region.excerpt.id);
1541                    buffer_edits
1542                        .entry(start_region.buffer.remote_id())
1543                        .or_default()
1544                        .push(BufferEdit {
1545                            range: start_excerpt_range,
1546                            new_text: new_text.clone(),
1547                            is_insertion: true,
1548                            original_indent_column,
1549                            excerpt_id: start_region.excerpt.id,
1550                        });
1551                }
1552                let excerpt_id = end_region.excerpt.id;
1553                if end_region.buffer.capability == Capability::ReadWrite
1554                    && end_region.is_main_buffer
1555                {
1556                    edited_excerpt_ids.push(excerpt_id);
1557                    buffer_edits
1558                        .entry(end_region.buffer.remote_id())
1559                        .or_default()
1560                        .push(BufferEdit {
1561                            range: end_excerpt_range,
1562                            new_text: new_text.clone(),
1563                            is_insertion: false,
1564                            original_indent_column,
1565                            excerpt_id,
1566                        });
1567                }
1568
1569                cursor.seek(&range.start);
1570                cursor.next_excerpt();
1571                while let Some(region) = cursor.region() {
1572                    if region.excerpt.id == excerpt_id {
1573                        break;
1574                    }
1575                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1576                        edited_excerpt_ids.push(region.excerpt.id);
1577                        buffer_edits
1578                            .entry(region.buffer.remote_id())
1579                            .or_default()
1580                            .push(BufferEdit {
1581                                range: region.buffer_range.clone(),
1582                                new_text: new_text.clone(),
1583                                is_insertion: false,
1584                                original_indent_column,
1585                                excerpt_id: region.excerpt.id,
1586                            });
1587                    }
1588                    cursor.next_excerpt();
1589                }
1590            }
1591        }
1592        (buffer_edits, edited_excerpt_ids)
1593    }
1594
1595    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1596    where
1597        I: IntoIterator<Item = Range<S>>,
1598        S: ToOffset,
1599    {
1600        if self.read_only() || self.buffers.is_empty() {
1601            return;
1602        }
1603        self.sync_mut(cx);
1604        let empty = Arc::<str>::from("");
1605        let edits = ranges
1606            .into_iter()
1607            .map(|range| {
1608                let mut range = range.start.to_offset(self.snapshot.get_mut())
1609                    ..range.end.to_offset(&self.snapshot.get_mut());
1610                if range.start > range.end {
1611                    mem::swap(&mut range.start, &mut range.end);
1612                }
1613                (range, empty.clone())
1614            })
1615            .collect::<Vec<_>>();
1616
1617        return autoindent_ranges_internal(self, edits, cx);
1618
1619        fn autoindent_ranges_internal(
1620            this: &mut MultiBuffer,
1621            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1622            cx: &mut Context<MultiBuffer>,
1623        ) {
1624            let (buffer_edits, edited_excerpt_ids) =
1625                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1626
1627            let mut buffer_ids = Vec::new();
1628            for (buffer_id, mut edits) in buffer_edits {
1629                buffer_ids.push(buffer_id);
1630                edits.sort_unstable_by_key(|edit| edit.range.start);
1631
1632                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1633                for edit in edits {
1634                    if let Some(last_range) = ranges.last_mut()
1635                        && edit.range.start <= last_range.end
1636                    {
1637                        last_range.end = last_range.end.max(edit.range.end);
1638                        continue;
1639                    }
1640                    ranges.push(edit.range);
1641                }
1642
1643                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1644                    buffer.autoindent_ranges(ranges, cx);
1645                })
1646            }
1647
1648            cx.emit(Event::ExcerptsEdited {
1649                excerpt_ids: edited_excerpt_ids,
1650                buffer_ids,
1651            });
1652        }
1653    }
1654
1655    pub fn set_active_selections(
1656        &self,
1657        selections: &[Selection<Anchor>],
1658        line_mode: bool,
1659        cursor_shape: CursorShape,
1660        cx: &mut Context<Self>,
1661    ) {
1662        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1663            Default::default();
1664        let snapshot = self.read(cx);
1665        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1666        for selection in selections {
1667            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1668            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1669
1670            cursor.seek(&Some(start_locator), Bias::Left);
1671            while let Some(excerpt) = cursor.item()
1672                && excerpt.locator <= *end_locator
1673            {
1674                let mut start = excerpt.range.context.start;
1675                let mut end = excerpt.range.context.end;
1676                if excerpt.id == selection.start.excerpt_id {
1677                    start = selection.start.text_anchor;
1678                }
1679                if excerpt.id == selection.end.excerpt_id {
1680                    end = selection.end.text_anchor;
1681                }
1682                selections_by_buffer
1683                    .entry(excerpt.buffer_id)
1684                    .or_default()
1685                    .push(Selection {
1686                        id: selection.id,
1687                        start,
1688                        end,
1689                        reversed: selection.reversed,
1690                        goal: selection.goal,
1691                    });
1692
1693                cursor.next();
1694            }
1695        }
1696
1697        for (buffer_id, buffer_state) in self.buffers.iter() {
1698            if !selections_by_buffer.contains_key(buffer_id) {
1699                buffer_state
1700                    .buffer
1701                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1702            }
1703        }
1704
1705        for (buffer_id, mut selections) in selections_by_buffer {
1706            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1707                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1708                let mut selections = selections.into_iter().peekable();
1709                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1710                    let mut selection = selections.next()?;
1711                    while let Some(next_selection) = selections.peek() {
1712                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1713                            let next_selection = selections.next().unwrap();
1714                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1715                                selection.end = next_selection.end;
1716                            }
1717                        } else {
1718                            break;
1719                        }
1720                    }
1721                    Some(selection)
1722                }));
1723                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1724            });
1725        }
1726    }
1727
1728    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1729        for buffer in self.buffers.values() {
1730            buffer
1731                .buffer
1732                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1733        }
1734    }
1735
1736    #[instrument(skip_all)]
1737    fn merge_excerpt_ranges<'a>(
1738        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1739    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1740        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1741        let mut counts: Vec<usize> = Vec::new();
1742        for range in expanded_ranges {
1743            if let Some(last_range) = merged_ranges.last_mut() {
1744                assert!(
1745                    last_range.context.start <= range.context.start,
1746                    "ranges must be sorted: {last_range:?} <= {range:?}"
1747                );
1748                if last_range.context.end >= range.context.start
1749                    || last_range.context.end.row + 1 == range.context.start.row
1750                {
1751                    last_range.context.end = range.context.end.max(last_range.context.end);
1752                    *counts.last_mut().unwrap() += 1;
1753                    continue;
1754                }
1755            }
1756            merged_ranges.push(range.clone());
1757            counts.push(1);
1758        }
1759        (merged_ranges, counts)
1760    }
1761
1762    pub fn insert_excerpts_after<O>(
1763        &mut self,
1764        prev_excerpt_id: ExcerptId,
1765        buffer: Entity<Buffer>,
1766        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1767        cx: &mut Context<Self>,
1768    ) -> Vec<ExcerptId>
1769    where
1770        O: text::ToOffset,
1771    {
1772        let mut ids = Vec::new();
1773        let mut next_excerpt_id =
1774            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1775                last_entry.id.0 + 1
1776            } else {
1777                1
1778            };
1779        self.insert_excerpts_with_ids_after(
1780            prev_excerpt_id,
1781            buffer,
1782            ranges.into_iter().map(|range| {
1783                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1784                ids.push(id);
1785                (id, range)
1786            }),
1787            cx,
1788        );
1789        ids
1790    }
1791
1792    pub fn insert_excerpts_with_ids_after<O>(
1793        &mut self,
1794        prev_excerpt_id: ExcerptId,
1795        buffer: Entity<Buffer>,
1796        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1797        cx: &mut Context<Self>,
1798    ) where
1799        O: text::ToOffset,
1800    {
1801        assert_eq!(self.history.transaction_depth(), 0);
1802        let mut ranges = ranges.into_iter().peekable();
1803        if ranges.peek().is_none() {
1804            return Default::default();
1805        }
1806
1807        self.sync_mut(cx);
1808
1809        let buffer_snapshot = buffer.read(cx).snapshot();
1810        let buffer_id = buffer_snapshot.remote_id();
1811
1812        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1813            self.buffer_changed_since_sync.replace(true);
1814            buffer.update(cx, |buffer, _| {
1815                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1816            });
1817            BufferState {
1818                last_version: RefCell::new(buffer_snapshot.version().clone()),
1819                last_non_text_state_update_count: Cell::new(
1820                    buffer_snapshot.non_text_state_update_count(),
1821                ),
1822                excerpts: Default::default(),
1823                _subscriptions: [
1824                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1825                    cx.subscribe(&buffer, Self::on_buffer_event),
1826                ],
1827                buffer: buffer.clone(),
1828            }
1829        });
1830
1831        let mut snapshot = self.snapshot.get_mut();
1832
1833        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1834        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1835        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1836        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1837        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1838
1839        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1840        new_excerpts.update_last(
1841            |excerpt| {
1842                excerpt.has_trailing_newline = true;
1843            },
1844            (),
1845        );
1846
1847        let next_locator = if let Some(excerpt) = cursor.item() {
1848            excerpt.locator.clone()
1849        } else {
1850            Locator::max()
1851        };
1852
1853        let mut excerpts = Vec::new();
1854        let buffer_snapshot = Arc::new(buffer_snapshot);
1855        while let Some((id, range)) = ranges.next() {
1856            let locator = Locator::between(&prev_locator, &next_locator);
1857            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1858                buffer_state.excerpts.insert(ix, locator.clone());
1859            }
1860            let range = ExcerptRange {
1861                context: buffer_snapshot.anchor_before(&range.context.start)
1862                    ..buffer_snapshot.anchor_after(&range.context.end),
1863                primary: buffer_snapshot.anchor_before(&range.primary.start)
1864                    ..buffer_snapshot.anchor_after(&range.primary.end),
1865            };
1866            excerpts.push((id, range.clone()));
1867            let excerpt = Excerpt::new(
1868                id,
1869                locator.clone(),
1870                buffer_id,
1871                buffer_snapshot.clone(),
1872                range,
1873                ranges.peek().is_some() || cursor.item().is_some(),
1874            );
1875            new_excerpts.push(excerpt, ());
1876            prev_locator = locator.clone();
1877
1878            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1879                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1880            }
1881            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1882        }
1883        snapshot
1884            .buffer_locators
1885            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1886
1887        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1888
1889        let suffix = cursor.suffix();
1890        let changed_trailing_excerpt = suffix.is_empty();
1891        new_excerpts.append(suffix, ());
1892        drop(cursor);
1893        snapshot.excerpts = new_excerpts;
1894        snapshot.excerpt_ids = new_excerpt_ids;
1895        if changed_trailing_excerpt {
1896            snapshot.trailing_excerpt_update_count += 1;
1897        }
1898
1899        let edits = Self::sync_diff_transforms(
1900            &mut snapshot,
1901            vec![Edit {
1902                old: edit_start..edit_start,
1903                new: edit_start..edit_end,
1904            }],
1905            DiffChangeKind::BufferEdited,
1906        );
1907        if !edits.is_empty() {
1908            self.subscriptions.publish(edits);
1909        }
1910
1911        cx.emit(Event::Edited {
1912            edited_buffer: None,
1913        });
1914        cx.emit(Event::ExcerptsAdded {
1915            buffer,
1916            predecessor: prev_excerpt_id,
1917            excerpts,
1918        });
1919        cx.notify();
1920    }
1921
1922    pub fn clear(&mut self, cx: &mut Context<Self>) {
1923        self.sync_mut(cx);
1924        let ids = self.excerpt_ids();
1925        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1926        self.excerpts_by_path.clear();
1927        self.paths_by_excerpt.clear();
1928        let MultiBufferSnapshot {
1929            excerpts,
1930            buffer_locators,
1931            diffs: _,
1932            diff_transforms: _,
1933            non_text_state_update_count: _,
1934            edit_count: _,
1935            is_dirty,
1936            has_deleted_file,
1937            has_conflict,
1938            has_inverted_diff,
1939            singleton: _,
1940            excerpt_ids: _,
1941            replaced_excerpts,
1942            trailing_excerpt_update_count,
1943            all_diff_hunks_expanded: _,
1944            show_deleted_hunks: _,
1945            use_extended_diff_range: _,
1946            show_headers: _,
1947        } = self.snapshot.get_mut();
1948        buffer_locators.clear();
1949        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1950        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1951        *excerpts = Default::default();
1952        *trailing_excerpt_update_count += 1;
1953        *is_dirty = false;
1954        *has_deleted_file = false;
1955        *has_conflict = false;
1956        *has_inverted_diff = false;
1957        match Arc::get_mut(replaced_excerpts) {
1958            Some(replaced_excerpts) => replaced_excerpts.clear(),
1959            None => *replaced_excerpts = Default::default(),
1960        }
1961
1962        let edits = Self::sync_diff_transforms(
1963            self.snapshot.get_mut(),
1964            vec![Edit {
1965                old: start..prev_len,
1966                new: start..start,
1967            }],
1968            DiffChangeKind::BufferEdited,
1969        );
1970        if !edits.is_empty() {
1971            self.subscriptions.publish(edits);
1972        }
1973        cx.emit(Event::Edited {
1974            edited_buffer: None,
1975        });
1976        cx.emit(Event::ExcerptsRemoved {
1977            ids,
1978            removed_buffer_ids,
1979        });
1980        cx.notify();
1981    }
1982
1983    #[ztracing::instrument(skip_all)]
1984    pub fn excerpts_for_buffer(
1985        &self,
1986        buffer_id: BufferId,
1987        cx: &App,
1988    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1989        let mut excerpts = Vec::new();
1990        let snapshot = self.read(cx);
1991        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1992        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1993            for locator in &**locators {
1994                cursor.seek_forward(&Some(locator), Bias::Left);
1995                if let Some(excerpt) = cursor.item()
1996                    && excerpt.locator == *locator
1997                {
1998                    excerpts.push((excerpt.id, excerpt.range.clone()));
1999                }
2000            }
2001        }
2002
2003        excerpts
2004    }
2005
2006    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2007        let snapshot = self.read(cx);
2008        let mut excerpts = snapshot
2009            .excerpts
2010            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2011        let mut diff_transforms = snapshot
2012            .diff_transforms
2013            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2014        diff_transforms.next();
2015        let locators = snapshot
2016            .buffer_locators
2017            .get(&buffer_id)
2018            .into_iter()
2019            .flat_map(|v| &**v);
2020        let mut result = Vec::new();
2021        for locator in locators {
2022            excerpts.seek_forward(&Some(locator), Bias::Left);
2023            if let Some(excerpt) = excerpts.item()
2024                && excerpt.locator == *locator
2025            {
2026                let excerpt_start = excerpts.start().1;
2027                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2028
2029                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2030                let overshoot = excerpt_start - diff_transforms.start().0;
2031                let start = diff_transforms.start().1 + overshoot;
2032
2033                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2034                let overshoot = excerpt_end - diff_transforms.start().0;
2035                let end = diff_transforms.start().1 + overshoot;
2036
2037                result.push(start.0..end.0)
2038            }
2039        }
2040        result
2041    }
2042
2043    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2044        self.snapshot
2045            .borrow()
2046            .excerpts
2047            .iter()
2048            .map(|entry| entry.buffer_id)
2049            .collect()
2050    }
2051
2052    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2053        let snapshot = self.snapshot.borrow();
2054        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2055        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2056        ids
2057    }
2058
2059    pub fn excerpt_containing(
2060        &self,
2061        position: impl ToOffset,
2062        cx: &App,
2063    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2064        let snapshot = self.read(cx);
2065        let offset = position.to_offset(&snapshot);
2066
2067        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2068        cursor.seek(&offset);
2069        cursor
2070            .excerpt()
2071            .or_else(|| snapshot.excerpts.last())
2072            .map(|excerpt| {
2073                (
2074                    excerpt.id,
2075                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2076                    excerpt.range.context.clone(),
2077                )
2078            })
2079    }
2080
2081    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2082        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2083            self.buffer(buffer_id)
2084        } else {
2085            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2086            Some(buffer)
2087        }
2088    }
2089
2090    // If point is at the end of the buffer, the last excerpt is returned
2091    pub fn point_to_buffer_offset<T: ToOffset>(
2092        &self,
2093        point: T,
2094        cx: &App,
2095    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2096        let snapshot = self.read(cx);
2097        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2098        Some((
2099            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2100            offset,
2101        ))
2102    }
2103
2104    // If point is at the end of the buffer, the last excerpt is returned
2105    pub fn point_to_buffer_point<T: ToPoint>(
2106        &self,
2107        point: T,
2108        cx: &App,
2109    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2110        let snapshot = self.read(cx);
2111        let (buffer, point, is_main_buffer) =
2112            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2113        Some((
2114            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2115            point,
2116            is_main_buffer,
2117        ))
2118    }
2119
2120    pub fn buffer_point_to_anchor(
2121        &self,
2122        // todo(lw): We shouldn't need this?
2123        buffer: &Entity<Buffer>,
2124        point: Point,
2125        cx: &App,
2126    ) -> Option<Anchor> {
2127        let mut found = None;
2128        let snapshot = buffer.read(cx).snapshot();
2129        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2130            let start = range.context.start.to_point(&snapshot);
2131            let end = range.context.end.to_point(&snapshot);
2132            if start <= point && point < end {
2133                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2134                break;
2135            }
2136            if point < start {
2137                found = Some((start, excerpt_id));
2138            }
2139            if point > end {
2140                found = Some((end, excerpt_id));
2141            }
2142        }
2143
2144        found.map(|(point, excerpt_id)| {
2145            let text_anchor = snapshot.anchor_after(point);
2146            Anchor::in_buffer(excerpt_id, text_anchor)
2147        })
2148    }
2149
2150    pub fn buffer_anchor_to_anchor(
2151        &self,
2152        // todo(lw): We shouldn't need this?
2153        buffer: &Entity<Buffer>,
2154        anchor: text::Anchor,
2155        cx: &App,
2156    ) -> Option<Anchor> {
2157        let snapshot = buffer.read(cx).snapshot();
2158        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2159            if range.context.start.cmp(&anchor, &snapshot).is_le()
2160                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2161            {
2162                return Some(Anchor::in_buffer(excerpt_id, anchor));
2163            }
2164        }
2165
2166        None
2167    }
2168
2169    pub fn merge_excerpts(
2170        &mut self,
2171        excerpt_ids: &[ExcerptId],
2172        cx: &mut Context<Self>,
2173    ) -> ExcerptId {
2174        debug_assert!(!excerpt_ids.is_empty());
2175        if excerpt_ids.len() == 1 {
2176            return excerpt_ids[0];
2177        }
2178
2179        let snapshot = self.snapshot(cx);
2180
2181        let first_range = snapshot
2182            .context_range_for_excerpt(excerpt_ids[0])
2183            .expect("first excerpt must exist");
2184        let last_range = snapshot
2185            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2186            .expect("last excerpt must exist");
2187
2188        let union_range = first_range.start..last_range.end;
2189
2190        drop(snapshot);
2191
2192        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2193        let removed = &excerpt_ids[1..];
2194        for &excerpt_id in removed {
2195            if let Some(path) = self.paths_by_excerpt.get(&excerpt_id) {
2196                if let Some(excerpt_list) = self.excerpts_by_path.get_mut(path) {
2197                    excerpt_list.retain(|id| *id != excerpt_id);
2198                    if excerpt_list.is_empty() {
2199                        let path = path.clone();
2200                        self.excerpts_by_path.remove(&path);
2201                    }
2202                }
2203            }
2204        }
2205        self.remove_excerpts(removed.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: Option<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 Some(diff_change_range) = diff_change_range else {
2514            return;
2515        };
2516
2517        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2518        let edits = Self::sync_diff_transforms(
2519            &mut snapshot,
2520            excerpt_edits,
2521            DiffChangeKind::DiffUpdated {
2522                // We don't read this field for inverted diffs.
2523                base_changed: false,
2524            },
2525        );
2526        if !edits.is_empty() {
2527            self.subscriptions.publish(edits);
2528        }
2529        cx.emit(Event::Edited {
2530            edited_buffer: None,
2531        });
2532    }
2533
2534    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2535        self.buffers.values().map(|state| state.buffer.clone())
2536    }
2537
2538    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2539        self.all_buffers_iter().collect()
2540    }
2541
2542    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2543        self.buffers.keys().copied()
2544    }
2545
2546    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2547        self.all_buffer_ids_iter().collect()
2548    }
2549
2550    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2551        self.buffers
2552            .get(&buffer_id)
2553            .map(|state| state.buffer.clone())
2554    }
2555
2556    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2557        self.point_to_buffer_offset(point, cx)
2558            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2559    }
2560
2561    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2562        let buffer_id = self
2563            .snapshot
2564            .borrow()
2565            .excerpts
2566            .first()
2567            .map(|excerpt| excerpt.buffer.remote_id());
2568        buffer_id
2569            .and_then(|buffer_id| self.buffer(buffer_id))
2570            .map(|buffer| {
2571                let buffer = buffer.read(cx);
2572                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2573            })
2574            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2575    }
2576
2577    pub fn language_settings_at<'a, T: ToOffset>(
2578        &'a self,
2579        point: T,
2580        cx: &'a App,
2581    ) -> Cow<'a, LanguageSettings> {
2582        let mut language = None;
2583        let mut file = None;
2584        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2585            let buffer = buffer.read(cx);
2586            language = buffer.language_at(offset);
2587            file = buffer.file();
2588        }
2589        language_settings(language.map(|l| l.name()), file, cx)
2590    }
2591
2592    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2593        self.buffers.values().for_each(|state| f(&state.buffer))
2594    }
2595
2596    pub fn explicit_title(&self) -> Option<&str> {
2597        self.title.as_deref()
2598    }
2599
2600    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2601        if let Some(title) = self.title.as_ref() {
2602            return title.into();
2603        }
2604
2605        if let Some(buffer) = self.as_singleton() {
2606            let buffer = buffer.read(cx);
2607
2608            if let Some(file) = buffer.file() {
2609                return file.file_name(cx).into();
2610            }
2611
2612            if let Some(title) = self.buffer_content_title(buffer) {
2613                return title;
2614            }
2615        };
2616
2617        "untitled".into()
2618    }
2619
2620    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2621        let mut is_leading_whitespace = true;
2622        let mut count = 0;
2623        let mut prev_was_space = false;
2624        let mut title = String::new();
2625
2626        for ch in buffer.snapshot().chars() {
2627            if is_leading_whitespace && ch.is_whitespace() {
2628                continue;
2629            }
2630
2631            is_leading_whitespace = false;
2632
2633            if ch == '\n' || count >= 40 {
2634                break;
2635            }
2636
2637            if ch.is_whitespace() {
2638                if !prev_was_space {
2639                    title.push(' ');
2640                    count += 1;
2641                    prev_was_space = true;
2642                }
2643            } else {
2644                title.push(ch);
2645                count += 1;
2646                prev_was_space = false;
2647            }
2648        }
2649
2650        let title = title.trim_end().to_string();
2651
2652        if title.is_empty() {
2653            return None;
2654        }
2655
2656        Some(title.into())
2657    }
2658
2659    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2660        self.title = Some(title);
2661        cx.notify();
2662    }
2663
2664    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2665    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2666        for buffer_state in self.buffers.values() {
2667            buffer_state
2668                .buffer
2669                .update(cx, |buffer, _cx| buffer.refresh_preview());
2670        }
2671    }
2672
2673    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2674    pub fn preserve_preview(&self, cx: &App) -> bool {
2675        self.buffers
2676            .values()
2677            .all(|state| state.buffer.read(cx).preserve_preview())
2678    }
2679
2680    #[cfg(any(test, feature = "test-support"))]
2681    pub fn is_parsing(&self, cx: &App) -> bool {
2682        self.as_singleton().unwrap().read(cx).is_parsing()
2683    }
2684
2685    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2686        let buffer_id = diff.read(cx).buffer_id;
2687
2688        if let Some(existing_diff) = self.diff_for(buffer_id)
2689            && diff.entity_id() == existing_diff.entity_id()
2690        {
2691            return;
2692        }
2693
2694        self.buffer_diff_changed(
2695            diff.clone(),
2696            text::Anchor::min_max_range_for_buffer(buffer_id),
2697            cx,
2698        );
2699        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2700    }
2701
2702    pub fn add_inverted_diff(
2703        &mut self,
2704        diff: Entity<BufferDiff>,
2705        main_buffer: Entity<language::Buffer>,
2706        cx: &mut Context<Self>,
2707    ) {
2708        let snapshot = diff.read(cx).base_text(cx);
2709        let base_text_buffer_id = snapshot.remote_id();
2710        let diff_change_range = 0..snapshot.len();
2711        self.snapshot.get_mut().has_inverted_diff = true;
2712        self.inverted_buffer_diff_changed(
2713            diff.clone(),
2714            main_buffer.clone(),
2715            Some(diff_change_range),
2716            cx,
2717        );
2718        self.diffs.insert(
2719            base_text_buffer_id,
2720            DiffState::new_inverted(diff, main_buffer, cx),
2721        );
2722    }
2723
2724    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2725        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2726    }
2727
2728    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2729        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2730    }
2731
2732    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2733        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2734    }
2735
2736    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2737        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2738        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2739    }
2740
2741    pub fn all_diff_hunks_expanded(&self) -> bool {
2742        self.snapshot.borrow().all_diff_hunks_expanded
2743    }
2744
2745    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2746        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2747        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2748    }
2749
2750    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2751        self.snapshot.get_mut().show_deleted_hunks = show;
2752
2753        self.sync_mut(cx);
2754
2755        let old_len = self.snapshot.borrow().len();
2756
2757        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2758        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2759
2760        let new_len = self.snapshot.borrow().len();
2761
2762        self.subscriptions.publish(vec![Edit {
2763            old: MultiBufferOffset(0)..old_len,
2764            new: MultiBufferOffset(0)..new_len,
2765        }]);
2766
2767        cx.emit(Event::DiffHunksToggled);
2768        cx.emit(Event::Edited {
2769            edited_buffer: None,
2770        });
2771    }
2772
2773    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2774        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2775    }
2776
2777    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2778        self.read(cx)
2779            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2780            .nth(1)
2781            .is_some()
2782    }
2783
2784    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2785        let snapshot = self.read(cx);
2786        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2787        let offset_range = range.to_offset(&snapshot);
2788        cursor.seek(&offset_range.start, Bias::Left);
2789        while let Some(item) = cursor.item() {
2790            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2791                break;
2792            }
2793            if item.hunk_info().is_some() {
2794                return true;
2795            }
2796            cursor.next();
2797        }
2798        false
2799    }
2800
2801    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2802        let snapshot = self.read(cx);
2803        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2804        for range in ranges {
2805            let range = range.to_point(&snapshot);
2806            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2807            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2808                .min(snapshot.len());
2809            cursor.seek(&start, Bias::Right);
2810            while let Some(item) = cursor.item() {
2811                if *cursor.start() >= end {
2812                    break;
2813                }
2814                if item.hunk_info().is_some() {
2815                    return true;
2816                }
2817                cursor.next();
2818            }
2819        }
2820        false
2821    }
2822
2823    pub fn expand_or_collapse_diff_hunks_inner(
2824        &mut self,
2825        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2826        expand: bool,
2827        cx: &mut Context<Self>,
2828    ) -> Vec<Edit<MultiBufferOffset>> {
2829        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2830            return Vec::new();
2831        }
2832        self.sync_mut(cx);
2833        let mut snapshot = self.snapshot.get_mut();
2834        let mut excerpt_edits = Vec::new();
2835        let mut last_hunk_row = None;
2836        for (range, end_excerpt_id) in ranges {
2837            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2838                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2839                    continue;
2840                }
2841                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2842                    continue;
2843                }
2844                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2845                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2846                let start = snapshot.excerpt_offset_for_anchor(&start);
2847                let end = snapshot.excerpt_offset_for_anchor(&end);
2848                last_hunk_row = Some(diff_hunk.row_range.start);
2849                excerpt_edits.push(text::Edit {
2850                    old: start..end,
2851                    new: start..end,
2852                });
2853            }
2854        }
2855
2856        Self::sync_diff_transforms(
2857            &mut snapshot,
2858            excerpt_edits,
2859            DiffChangeKind::ExpandOrCollapseHunks { expand },
2860        )
2861    }
2862
2863    pub fn expand_or_collapse_diff_hunks(
2864        &mut self,
2865        ranges: Vec<Range<Anchor>>,
2866        expand: bool,
2867        cx: &mut Context<Self>,
2868    ) {
2869        let snapshot = self.snapshot.borrow().clone();
2870        let ranges = ranges.iter().map(move |range| {
2871            let end_excerpt_id = range.end.excerpt_id;
2872            let range = range.to_point(&snapshot);
2873            let mut peek_end = range.end;
2874            if range.end.row < snapshot.max_row().0 {
2875                peek_end = Point::new(range.end.row + 1, 0);
2876            };
2877            (range.start..peek_end, end_excerpt_id)
2878        });
2879        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2880        if !edits.is_empty() {
2881            self.subscriptions.publish(edits);
2882        }
2883        cx.emit(Event::DiffHunksToggled);
2884        cx.emit(Event::Edited {
2885            edited_buffer: None,
2886        });
2887    }
2888
2889    pub fn resize_excerpt(
2890        &mut self,
2891        id: ExcerptId,
2892        range: Range<text::Anchor>,
2893        cx: &mut Context<Self>,
2894    ) {
2895        self.sync_mut(cx);
2896
2897        let mut snapshot = self.snapshot.get_mut();
2898        let locator = snapshot.excerpt_locator_for_id(id);
2899        let mut new_excerpts = SumTree::default();
2900        let mut cursor = snapshot
2901            .excerpts
2902            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2903        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2904
2905        let prefix = cursor.slice(&Some(locator), Bias::Left);
2906        new_excerpts.append(prefix, ());
2907
2908        let mut excerpt = cursor.item().unwrap().clone();
2909        let old_text_len = excerpt.text_summary.len;
2910
2911        excerpt.range.context.start = range.start;
2912        excerpt.range.context.end = range.end;
2913        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2914
2915        excerpt.text_summary = excerpt
2916            .buffer
2917            .text_summary_for_range(excerpt.range.context.clone());
2918
2919        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2920        let old_start_offset = cursor.start().1;
2921        let new_text_len = excerpt.text_summary.len;
2922        let edit = Edit {
2923            old: old_start_offset..old_start_offset + old_text_len,
2924            new: new_start_offset..new_start_offset + new_text_len,
2925        };
2926
2927        if let Some(last_edit) = edits.last_mut() {
2928            if last_edit.old.end == edit.old.start {
2929                last_edit.old.end = edit.old.end;
2930                last_edit.new.end = edit.new.end;
2931            } else {
2932                edits.push(edit);
2933            }
2934        } else {
2935            edits.push(edit);
2936        }
2937
2938        new_excerpts.push(excerpt, ());
2939
2940        cursor.next();
2941
2942        new_excerpts.append(cursor.suffix(), ());
2943
2944        drop(cursor);
2945        snapshot.excerpts = new_excerpts;
2946
2947        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2948        if !edits.is_empty() {
2949            self.subscriptions.publish(edits);
2950        }
2951        cx.emit(Event::Edited {
2952            edited_buffer: None,
2953        });
2954        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2955        cx.notify();
2956    }
2957
2958    pub fn expand_excerpts(
2959        &mut self,
2960        ids: impl IntoIterator<Item = ExcerptId>,
2961        line_count: u32,
2962        direction: ExpandExcerptDirection,
2963        cx: &mut Context<Self>,
2964    ) {
2965        if line_count == 0 {
2966            return;
2967        }
2968        self.sync_mut(cx);
2969        if !self.excerpts_by_path.is_empty() {
2970            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2971            return;
2972        }
2973        let mut snapshot = self.snapshot.get_mut();
2974
2975        let ids = ids.into_iter().collect::<Vec<_>>();
2976        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2977        let mut new_excerpts = SumTree::default();
2978        let mut cursor = snapshot
2979            .excerpts
2980            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2981        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2982
2983        for locator in &locators {
2984            let prefix = cursor.slice(&Some(locator), Bias::Left);
2985            new_excerpts.append(prefix, ());
2986
2987            let mut excerpt = cursor.item().unwrap().clone();
2988            let old_text_len = excerpt.text_summary.len;
2989
2990            let up_line_count = if direction.should_expand_up() {
2991                line_count
2992            } else {
2993                0
2994            };
2995
2996            let start_row = excerpt
2997                .range
2998                .context
2999                .start
3000                .to_point(&excerpt.buffer)
3001                .row
3002                .saturating_sub(up_line_count);
3003            let start_point = Point::new(start_row, 0);
3004            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
3005
3006            let down_line_count = if direction.should_expand_down() {
3007                line_count
3008            } else {
3009                0
3010            };
3011
3012            let mut end_point = excerpt.buffer.clip_point(
3013                excerpt.range.context.end.to_point(&excerpt.buffer)
3014                    + Point::new(down_line_count, 0),
3015                Bias::Left,
3016            );
3017            end_point.column = excerpt.buffer.line_len(end_point.row);
3018            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
3019            excerpt.max_buffer_row = end_point.row;
3020
3021            excerpt.text_summary = excerpt
3022                .buffer
3023                .text_summary_for_range(excerpt.range.context.clone());
3024
3025            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
3026            let old_start_offset = cursor.start().1;
3027            let new_text_len = excerpt.text_summary.len;
3028            let edit = Edit {
3029                old: old_start_offset..old_start_offset + old_text_len,
3030                new: new_start_offset..new_start_offset + new_text_len,
3031            };
3032
3033            if let Some(last_edit) = edits.last_mut() {
3034                if last_edit.old.end == edit.old.start {
3035                    last_edit.old.end = edit.old.end;
3036                    last_edit.new.end = edit.new.end;
3037                } else {
3038                    edits.push(edit);
3039                }
3040            } else {
3041                edits.push(edit);
3042            }
3043
3044            new_excerpts.push(excerpt, ());
3045
3046            cursor.next();
3047        }
3048
3049        new_excerpts.append(cursor.suffix(), ());
3050
3051        drop(cursor);
3052        snapshot.excerpts = new_excerpts;
3053
3054        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3055        if !edits.is_empty() {
3056            self.subscriptions.publish(edits);
3057        }
3058        cx.emit(Event::Edited {
3059            edited_buffer: None,
3060        });
3061        cx.emit(Event::ExcerptsExpanded { ids });
3062        cx.notify();
3063    }
3064
3065    #[ztracing::instrument(skip_all)]
3066    fn sync(&self, cx: &App) {
3067        let changed = self.buffer_changed_since_sync.replace(false);
3068        if !changed {
3069            return;
3070        }
3071        let edits = Self::sync_from_buffer_changes(
3072            &mut self.snapshot.borrow_mut(),
3073            &self.buffers,
3074            &self.diffs,
3075            cx,
3076        );
3077        if !edits.is_empty() {
3078            self.subscriptions.publish(edits);
3079        }
3080    }
3081
3082    fn sync_mut(&mut self, cx: &App) {
3083        let changed = self.buffer_changed_since_sync.replace(false);
3084        if !changed {
3085            return;
3086        }
3087        let edits =
3088            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3089
3090        if !edits.is_empty() {
3091            self.subscriptions.publish(edits);
3092        }
3093    }
3094
3095    fn sync_from_buffer_changes(
3096        snapshot: &mut MultiBufferSnapshot,
3097        buffers: &BTreeMap<BufferId, BufferState>,
3098        diffs: &HashMap<BufferId, DiffState>,
3099        cx: &App,
3100    ) -> Vec<Edit<MultiBufferOffset>> {
3101        let MultiBufferSnapshot {
3102            excerpts,
3103            buffer_locators: _,
3104            diffs: buffer_diff,
3105            diff_transforms: _,
3106            non_text_state_update_count,
3107            edit_count,
3108            is_dirty,
3109            has_deleted_file,
3110            has_conflict,
3111            has_inverted_diff: _,
3112            singleton: _,
3113            excerpt_ids: _,
3114            replaced_excerpts: _,
3115            trailing_excerpt_update_count: _,
3116            all_diff_hunks_expanded: _,
3117            show_deleted_hunks: _,
3118            use_extended_diff_range: _,
3119            show_headers: _,
3120        } = snapshot;
3121        *is_dirty = false;
3122        *has_deleted_file = false;
3123        *has_conflict = false;
3124
3125        if !diffs.is_empty() {
3126            let mut diffs_to_add = Vec::new();
3127            for (id, diff) in diffs {
3128                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3129                // and use the diff hunk base text ranges to compute diff transforms.
3130                // Those base text ranges are usize, so make sure if the base text changed
3131                // we also update the diff snapshot so that we don't use stale offsets
3132                if buffer_diff.get(id).is_none_or(|existing_diff| {
3133                    if existing_diff.main_buffer.is_none() {
3134                        return false;
3135                    }
3136                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3137                    base_text.remote_id() != existing_diff.base_text().remote_id()
3138                        || base_text
3139                            .version()
3140                            .changed_since(existing_diff.base_text().version())
3141                }) {
3142                    if diffs_to_add.capacity() == 0 {
3143                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3144                        // meaning re-allocations will be fairly expensive
3145                        diffs_to_add.reserve(diffs.len());
3146                    }
3147                    diffs_to_add.push((*id, diff.snapshot(cx)));
3148                }
3149            }
3150            buffer_diff.extend(diffs_to_add);
3151        }
3152
3153        let mut excerpts_to_edit = Vec::new();
3154        let mut non_text_state_updated = false;
3155        let mut edited = false;
3156        for buffer_state in buffers.values() {
3157            let buffer = buffer_state.buffer.read(cx);
3158            let version = buffer.version();
3159            let non_text_state_update_count = buffer.non_text_state_update_count();
3160
3161            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3162            let buffer_non_text_state_updated =
3163                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3164            if buffer_edited || buffer_non_text_state_updated {
3165                *buffer_state.last_version.borrow_mut() = version;
3166                buffer_state
3167                    .last_non_text_state_update_count
3168                    .set(non_text_state_update_count);
3169                excerpts_to_edit.extend(
3170                    buffer_state
3171                        .excerpts
3172                        .iter()
3173                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3174                );
3175            }
3176
3177            edited |= buffer_edited;
3178            non_text_state_updated |= buffer_non_text_state_updated;
3179            *is_dirty |= buffer.is_dirty();
3180            *has_deleted_file |= buffer
3181                .file()
3182                .is_some_and(|file| file.disk_state().is_deleted());
3183            *has_conflict |= buffer.has_conflict();
3184        }
3185        if edited {
3186            *edit_count += 1;
3187        }
3188        if non_text_state_updated {
3189            *non_text_state_update_count += 1;
3190        }
3191
3192        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3193
3194        let mut edits = Vec::new();
3195        let mut new_excerpts = SumTree::default();
3196        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3197
3198        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3199            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3200            let old_excerpt = cursor.item().unwrap();
3201            let buffer = buffer.read(cx);
3202            let buffer_id = buffer.remote_id();
3203            let mut new_excerpt;
3204            if buffer_edited {
3205                edits.extend(
3206                    buffer
3207                        .edits_since_in_range::<usize>(
3208                            old_excerpt.buffer.version(),
3209                            old_excerpt.range.context.clone(),
3210                        )
3211                        .map(|edit| {
3212                            let excerpt_old_start = cursor.start().1;
3213                            let excerpt_new_start =
3214                                ExcerptDimension(new_excerpts.summary().text.len);
3215                            let old_start = excerpt_old_start + edit.old.start;
3216                            let old_end = excerpt_old_start + edit.old.end;
3217                            let new_start = excerpt_new_start + edit.new.start;
3218                            let new_end = excerpt_new_start + edit.new.end;
3219                            Edit {
3220                                old: old_start..old_end,
3221                                new: new_start..new_end,
3222                            }
3223                        }),
3224                );
3225
3226                new_excerpt = Excerpt::new(
3227                    old_excerpt.id,
3228                    locator.clone(),
3229                    buffer_id,
3230                    Arc::new(buffer.snapshot()),
3231                    old_excerpt.range.clone(),
3232                    old_excerpt.has_trailing_newline,
3233                );
3234            } else {
3235                new_excerpt = old_excerpt.clone();
3236                new_excerpt.buffer = Arc::new(buffer.snapshot());
3237            }
3238
3239            new_excerpts.push(new_excerpt, ());
3240            cursor.next();
3241        }
3242        new_excerpts.append(cursor.suffix(), ());
3243
3244        drop(cursor);
3245        *excerpts = new_excerpts;
3246
3247        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3248    }
3249
3250    fn sync_diff_transforms(
3251        snapshot: &mut MultiBufferSnapshot,
3252        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3253        change_kind: DiffChangeKind,
3254    ) -> Vec<Edit<MultiBufferOffset>> {
3255        if excerpt_edits.is_empty() {
3256            return vec![];
3257        }
3258
3259        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3260        let mut old_diff_transforms = snapshot
3261            .diff_transforms
3262            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3263        let mut new_diff_transforms = SumTree::default();
3264        let mut old_expanded_hunks = HashSet::default();
3265        let mut output_edits = Vec::new();
3266        let mut output_delta = 0_isize;
3267        let mut at_transform_boundary = true;
3268        let mut end_of_current_insert = None;
3269
3270        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3271        while let Some(edit) = excerpt_edits.next() {
3272            excerpts.seek_forward(&edit.new.start, Bias::Right);
3273            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3274                excerpts.prev();
3275            }
3276
3277            // Keep any transforms that are before the edit.
3278            if at_transform_boundary {
3279                at_transform_boundary = false;
3280                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3281                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3282                if let Some(transform) = old_diff_transforms.item()
3283                    && old_diff_transforms.end().0 == edit.old.start
3284                    && old_diff_transforms.start().0 < edit.old.start
3285                {
3286                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3287                    old_diff_transforms.next();
3288                }
3289            }
3290
3291            // Compute the start of the edit in output coordinates.
3292            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3293            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3294            let edit_new_start =
3295                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3296
3297            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3298                &edit,
3299                &mut excerpts,
3300                &mut old_diff_transforms,
3301                &mut new_diff_transforms,
3302                &mut end_of_current_insert,
3303                &mut old_expanded_hunks,
3304                snapshot,
3305                change_kind,
3306            );
3307
3308            // Compute the end of the edit in output coordinates.
3309            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3310            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3311            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3312            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3313            let output_edit = Edit {
3314                old: edit_old_start..edit_old_end,
3315                new: edit_new_start..edit_new_end,
3316            };
3317
3318            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3319            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3320            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3321                output_edits.push(output_edit);
3322            }
3323
3324            // If this is the last edit that intersects the current diff transform,
3325            // then recreate the content up to the end of this transform, to prepare
3326            // for reusing additional slices of the old transforms.
3327            if excerpt_edits
3328                .peek()
3329                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3330            {
3331                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3332                    && match old_diff_transforms.item() {
3333                        Some(DiffTransform::BufferContent {
3334                            inserted_hunk_info: Some(hunk),
3335                            ..
3336                        }) => excerpts.item().is_some_and(|excerpt| {
3337                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3338                                && diff.main_buffer.is_some()
3339                            {
3340                                return true;
3341                            }
3342                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3343                        }),
3344                        _ => true,
3345                    };
3346
3347                let mut excerpt_offset = edit.new.end;
3348                if !keep_next_old_transform {
3349                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3350                    old_diff_transforms.next();
3351                }
3352
3353                old_expanded_hunks.clear();
3354                Self::push_buffer_content_transform(
3355                    snapshot,
3356                    &mut new_diff_transforms,
3357                    excerpt_offset,
3358                    end_of_current_insert,
3359                );
3360                at_transform_boundary = true;
3361            }
3362        }
3363
3364        // Keep any transforms that are after the last edit.
3365        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3366
3367        // Ensure there's always at least one buffer content transform.
3368        if new_diff_transforms.is_empty() {
3369            new_diff_transforms.push(
3370                DiffTransform::BufferContent {
3371                    summary: Default::default(),
3372                    inserted_hunk_info: None,
3373                },
3374                (),
3375            );
3376        }
3377
3378        drop(old_diff_transforms);
3379        drop(excerpts);
3380        snapshot.diff_transforms = new_diff_transforms;
3381        snapshot.edit_count += 1;
3382
3383        #[cfg(any(test, feature = "test-support"))]
3384        snapshot.check_invariants();
3385        output_edits
3386    }
3387
3388    fn recompute_diff_transforms_for_edit(
3389        edit: &Edit<ExcerptOffset>,
3390        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3391        old_diff_transforms: &mut Cursor<
3392            DiffTransform,
3393            Dimensions<ExcerptOffset, MultiBufferOffset>,
3394        >,
3395        new_diff_transforms: &mut SumTree<DiffTransform>,
3396        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3397        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3398        snapshot: &MultiBufferSnapshot,
3399        change_kind: DiffChangeKind,
3400    ) -> bool {
3401        log::trace!(
3402            "recomputing diff transform for edit {:?} => {:?}",
3403            edit.old.start..edit.old.end,
3404            edit.new.start..edit.new.end
3405        );
3406
3407        // Record which hunks were previously expanded.
3408        while let Some(item) = old_diff_transforms.item() {
3409            if let Some(hunk_info) = item.hunk_info() {
3410                log::trace!(
3411                    "previously expanded hunk at {:?}",
3412                    old_diff_transforms.start()
3413                );
3414                old_expanded_hunks.insert(hunk_info);
3415            }
3416            if old_diff_transforms.end().0 > edit.old.end {
3417                break;
3418            }
3419            old_diff_transforms.next();
3420        }
3421
3422        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3423        // For inverted diffs, hunks are always shown, so we can't skip this.
3424        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3425        if old_expanded_hunks.is_empty()
3426            && change_kind == DiffChangeKind::BufferEdited
3427            && !all_diff_hunks_expanded
3428            && !snapshot.has_inverted_diff
3429        {
3430            return false;
3431        }
3432
3433        // Visit each excerpt that intersects the edit.
3434        let mut did_expand_hunks = false;
3435        while let Some(excerpt) = excerpts.item() {
3436            // Recompute the expanded hunks in the portion of the excerpt that
3437            // intersects the edit.
3438            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3439                let buffer = &excerpt.buffer;
3440                let excerpt_start = *excerpts.start();
3441                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3442                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3443                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3444                let edit_buffer_start =
3445                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3446                let edit_buffer_end =
3447                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3448                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3449
3450                if let Some(main_buffer) = &diff.main_buffer {
3451                    for hunk in diff.hunks_intersecting_base_text_range(
3452                        edit_buffer_start..edit_buffer_end,
3453                        main_buffer,
3454                    ) {
3455                        did_expand_hunks = true;
3456                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3457                        if hunk_buffer_range.start < excerpt_buffer_start {
3458                            log::trace!("skipping hunk that starts before excerpt");
3459                            continue;
3460                        }
3461                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3462                        let hunk_excerpt_start = excerpt_start
3463                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3464                        let hunk_excerpt_end = excerpt_end
3465                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3466                        Self::push_buffer_content_transform(
3467                            snapshot,
3468                            new_diff_transforms,
3469                            hunk_excerpt_start,
3470                            *end_of_current_insert,
3471                        );
3472                        if !hunk_buffer_range.is_empty() {
3473                            let hunk_info = DiffTransformHunkInfo {
3474                                excerpt_id: excerpt.id,
3475                                hunk_start_anchor: hunk.buffer_range.start,
3476                                hunk_secondary_status: hunk.secondary_status,
3477                                is_logically_deleted: true,
3478                            };
3479                            *end_of_current_insert =
3480                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3481                        }
3482                    }
3483                } else {
3484                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3485                        ..buffer.anchor_after(edit_buffer_end);
3486                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3487                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3488                            continue;
3489                        }
3490
3491                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3492                        if hunk_buffer_range.start < excerpt_buffer_start {
3493                            log::trace!("skipping hunk that starts before excerpt");
3494                            continue;
3495                        }
3496
3497                        let hunk_info = DiffTransformHunkInfo {
3498                            excerpt_id: excerpt.id,
3499                            hunk_start_anchor: hunk.buffer_range.start,
3500                            hunk_secondary_status: hunk.secondary_status,
3501                            is_logically_deleted: false,
3502                        };
3503
3504                        let hunk_excerpt_start = excerpt_start
3505                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3506                        let hunk_excerpt_end = excerpt_end
3507                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3508
3509                        Self::push_buffer_content_transform(
3510                            snapshot,
3511                            new_diff_transforms,
3512                            hunk_excerpt_start,
3513                            *end_of_current_insert,
3514                        );
3515
3516                        // For every existing hunk, determine if it was previously expanded
3517                        // and if it should currently be expanded.
3518                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3519                        let should_expand_hunk = match &change_kind {
3520                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3521                                was_previously_expanded || all_diff_hunks_expanded
3522                            }
3523                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3524                                let intersects = hunk_buffer_range.is_empty()
3525                                    || hunk_buffer_range.end > edit_buffer_start;
3526                                if *expand {
3527                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3528                                } else {
3529                                    !intersects
3530                                        && (was_previously_expanded || all_diff_hunks_expanded)
3531                                }
3532                            }
3533                            _ => was_previously_expanded || all_diff_hunks_expanded,
3534                        };
3535
3536                        if should_expand_hunk {
3537                            did_expand_hunks = true;
3538                            log::trace!(
3539                                "expanding hunk {:?}, excerpt:{:?}",
3540                                hunk_excerpt_start..hunk_excerpt_end,
3541                                excerpt.id
3542                            );
3543
3544                            if !hunk.diff_base_byte_range.is_empty()
3545                                && hunk_buffer_range.start >= edit_buffer_start
3546                                && hunk_buffer_range.start <= excerpt_buffer_end
3547                                && snapshot.show_deleted_hunks
3548                            {
3549                                let base_text = diff.base_text();
3550                                let mut text_cursor =
3551                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3552                                let mut base_text_summary = text_cursor
3553                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3554
3555                                let mut has_trailing_newline = false;
3556                                if base_text_summary.last_line_chars > 0 {
3557                                    base_text_summary += TextSummary::newline();
3558                                    has_trailing_newline = true;
3559                                }
3560
3561                                new_diff_transforms.push(
3562                                    DiffTransform::DeletedHunk {
3563                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3564                                        summary: base_text_summary,
3565                                        buffer_id: excerpt.buffer_id,
3566                                        hunk_info,
3567                                        has_trailing_newline,
3568                                    },
3569                                    (),
3570                                );
3571                            }
3572
3573                            if !hunk_buffer_range.is_empty() {
3574                                *end_of_current_insert =
3575                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3576                            }
3577                        }
3578                    }
3579                }
3580            }
3581
3582            if excerpts.end() <= edit.new.end {
3583                excerpts.next();
3584            } else {
3585                break;
3586            }
3587        }
3588
3589        did_expand_hunks || !old_expanded_hunks.is_empty()
3590    }
3591
3592    fn append_diff_transforms(
3593        new_transforms: &mut SumTree<DiffTransform>,
3594        subtree: SumTree<DiffTransform>,
3595    ) {
3596        if let Some(DiffTransform::BufferContent {
3597            inserted_hunk_info,
3598            summary,
3599        }) = subtree.first()
3600            && Self::extend_last_buffer_content_transform(
3601                new_transforms,
3602                *inserted_hunk_info,
3603                *summary,
3604            )
3605        {
3606            let mut cursor = subtree.cursor::<()>(());
3607            cursor.next();
3608            cursor.next();
3609            new_transforms.append(cursor.suffix(), ());
3610            return;
3611        }
3612        new_transforms.append(subtree, ());
3613    }
3614
3615    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3616        if let DiffTransform::BufferContent {
3617            inserted_hunk_info: inserted_hunk_anchor,
3618            summary,
3619        } = transform
3620            && Self::extend_last_buffer_content_transform(
3621                new_transforms,
3622                inserted_hunk_anchor,
3623                summary,
3624            )
3625        {
3626            return;
3627        }
3628        new_transforms.push(transform, ());
3629    }
3630
3631    fn push_buffer_content_transform(
3632        old_snapshot: &MultiBufferSnapshot,
3633        new_transforms: &mut SumTree<DiffTransform>,
3634        end_offset: ExcerptOffset,
3635        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3636    ) {
3637        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3638            (end_offset.min(insertion_end_offset), Some(hunk_info))
3639        });
3640        let unchanged_region = [(end_offset, None)];
3641
3642        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3643        {
3644            let start_offset = new_transforms.summary().excerpt_len();
3645            if end_offset <= start_offset {
3646                continue;
3647            }
3648            let summary_to_add = old_snapshot
3649                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3650
3651            if !Self::extend_last_buffer_content_transform(
3652                new_transforms,
3653                inserted_hunk_info,
3654                summary_to_add,
3655            ) {
3656                new_transforms.push(
3657                    DiffTransform::BufferContent {
3658                        summary: summary_to_add,
3659                        inserted_hunk_info,
3660                    },
3661                    (),
3662                )
3663            }
3664        }
3665    }
3666
3667    fn extend_last_buffer_content_transform(
3668        new_transforms: &mut SumTree<DiffTransform>,
3669        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3670        summary_to_add: MBTextSummary,
3671    ) -> bool {
3672        let mut did_extend = false;
3673        new_transforms.update_last(
3674            |last_transform| {
3675                if let DiffTransform::BufferContent {
3676                    summary,
3677                    inserted_hunk_info: inserted_hunk_anchor,
3678                } = last_transform
3679                    && *inserted_hunk_anchor == new_inserted_hunk_info
3680                {
3681                    *summary += summary_to_add;
3682                    did_extend = true;
3683                }
3684            },
3685            (),
3686        );
3687        did_extend
3688    }
3689
3690    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3691        let snapshot = self.snapshot(cx);
3692        let excerpt_id = range.end.excerpt_id;
3693        let point_range = range.to_point(&snapshot);
3694        let expand = !self.single_hunk_is_expanded(range, cx);
3695        let edits =
3696            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3697        if !edits.is_empty() {
3698            self.subscriptions.publish(edits);
3699        }
3700        cx.emit(Event::DiffHunksToggled);
3701        cx.emit(Event::Edited {
3702            edited_buffer: None,
3703        });
3704    }
3705}
3706
3707fn build_excerpt_ranges(
3708    ranges: impl IntoIterator<Item = Range<Point>>,
3709    context_line_count: u32,
3710    buffer_snapshot: &BufferSnapshot,
3711) -> Vec<ExcerptRange<Point>> {
3712    ranges
3713        .into_iter()
3714        .map(|range| {
3715            let start_row = range.start.row.saturating_sub(context_line_count);
3716            let start = Point::new(start_row, 0);
3717            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3718            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3719            ExcerptRange {
3720                context: start..end,
3721                primary: range,
3722            }
3723        })
3724        .collect()
3725}
3726
3727#[cfg(any(test, feature = "test-support"))]
3728impl MultiBuffer {
3729    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3730        let buffer = cx.new(|cx| Buffer::local(text, cx));
3731        cx.new(|cx| Self::singleton(buffer, cx))
3732    }
3733
3734    pub fn build_multi<const COUNT: usize>(
3735        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3736        cx: &mut gpui::App,
3737    ) -> Entity<Self> {
3738        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3739        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3740            let buffer = cx.new(|cx| Buffer::local(text, cx));
3741            let snapshot = buffer.read(cx).snapshot();
3742            let excerpt_ranges = ranges
3743                .into_iter()
3744                .map(ExcerptRange::new)
3745                .collect::<Vec<_>>();
3746            multi.update(cx, |multi, cx| {
3747                multi.set_excerpt_ranges_for_path(
3748                    PathKey::sorted(ix as u64),
3749                    buffer,
3750                    &snapshot,
3751                    excerpt_ranges,
3752                    cx,
3753                )
3754            });
3755        }
3756
3757        multi
3758    }
3759
3760    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3761        cx.new(|cx| Self::singleton(buffer, cx))
3762    }
3763
3764    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3765        cx.new(|cx| {
3766            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3767            let mutation_count = rng.random_range(1..=5);
3768            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3769            multibuffer
3770        })
3771    }
3772
3773    pub fn randomly_edit(
3774        &mut self,
3775        rng: &mut impl rand::Rng,
3776        edit_count: usize,
3777        cx: &mut Context<Self>,
3778    ) {
3779        use util::RandomCharIter;
3780
3781        let snapshot = self.read(cx);
3782        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3783        let mut last_end = None;
3784        for _ in 0..edit_count {
3785            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3786                break;
3787            }
3788
3789            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3790            let end =
3791                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3792            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3793            last_end = Some(end);
3794
3795            let mut range = start..end;
3796            if rng.random_bool(0.2) {
3797                mem::swap(&mut range.start, &mut range.end);
3798            }
3799
3800            let new_text_len = rng.random_range(0..10);
3801            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3802
3803            edits.push((range, new_text.into()));
3804        }
3805        log::info!("mutating multi-buffer with {:?}", edits);
3806        drop(snapshot);
3807
3808        self.edit(edits, None, cx);
3809    }
3810
3811    pub fn randomly_edit_excerpts(
3812        &mut self,
3813        rng: &mut impl rand::Rng,
3814        mutation_count: usize,
3815        cx: &mut Context<Self>,
3816    ) {
3817        use rand::prelude::*;
3818        use std::env;
3819        use util::RandomCharIter;
3820
3821        let max_excerpts = env::var("MAX_EXCERPTS")
3822            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3823            .unwrap_or(5);
3824
3825        let mut buffers = Vec::new();
3826        for _ in 0..mutation_count {
3827            if rng.random_bool(0.05) {
3828                log::info!("Clearing multi-buffer");
3829                self.clear(cx);
3830                continue;
3831            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3832                let ids = self.excerpt_ids();
3833                let mut excerpts = HashSet::default();
3834                for _ in 0..rng.random_range(0..ids.len()) {
3835                    excerpts.extend(ids.choose(rng).copied());
3836                }
3837
3838                let line_count = rng.random_range(0..5);
3839
3840                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3841
3842                self.expand_excerpts(
3843                    excerpts.iter().cloned(),
3844                    line_count,
3845                    ExpandExcerptDirection::UpAndDown,
3846                    cx,
3847                );
3848                continue;
3849            }
3850
3851            let excerpt_ids = self.excerpt_ids();
3852            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3853                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3854                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3855                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3856                    let buffer = buffers.last().unwrap().read(cx);
3857                    log::info!(
3858                        "Creating new buffer {} with text: {:?}",
3859                        buffer.remote_id(),
3860                        buffer.text()
3861                    );
3862                    buffers.last().unwrap().clone()
3863                } else {
3864                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3865                };
3866
3867                let buffer = buffer_handle.read(cx);
3868                let buffer_text = buffer.text();
3869                let ranges = (0..rng.random_range(0..5))
3870                    .map(|_| {
3871                        let end_ix =
3872                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3873                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3874                        ExcerptRange::new(start_ix..end_ix)
3875                    })
3876                    .collect::<Vec<_>>();
3877                log::info!(
3878                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3879                    buffer_handle.read(cx).remote_id(),
3880                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3881                    ranges
3882                        .iter()
3883                        .map(|r| &buffer_text[r.context.clone()])
3884                        .collect::<Vec<_>>()
3885                );
3886
3887                let excerpt_id =
3888                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3889                log::info!("Inserted with ids: {:?}", excerpt_id);
3890            } else {
3891                let remove_count = rng.random_range(1..=excerpt_ids.len());
3892                let mut excerpts_to_remove = excerpt_ids
3893                    .choose_multiple(rng, remove_count)
3894                    .cloned()
3895                    .collect::<Vec<_>>();
3896                let snapshot = self.snapshot.borrow();
3897                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3898                drop(snapshot);
3899                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3900                self.remove_excerpts(excerpts_to_remove, cx);
3901            }
3902        }
3903    }
3904
3905    pub fn randomly_mutate(
3906        &mut self,
3907        rng: &mut impl rand::Rng,
3908        mutation_count: usize,
3909        cx: &mut Context<Self>,
3910    ) {
3911        use rand::prelude::*;
3912
3913        if rng.random_bool(0.7) || self.singleton {
3914            let buffer = self
3915                .buffers
3916                .values()
3917                .choose(rng)
3918                .map(|state| state.buffer.clone());
3919
3920            if let Some(buffer) = buffer {
3921                buffer.update(cx, |buffer, cx| {
3922                    if rng.random() {
3923                        buffer.randomly_edit(rng, mutation_count, cx);
3924                    } else {
3925                        buffer.randomly_undo_redo(rng, cx);
3926                    }
3927                });
3928            } else {
3929                self.randomly_edit(rng, mutation_count, cx);
3930            }
3931        } else {
3932            self.randomly_edit_excerpts(rng, mutation_count, cx);
3933        }
3934
3935        self.check_invariants(cx);
3936    }
3937
3938    fn check_invariants(&self, cx: &App) {
3939        self.read(cx).check_invariants();
3940    }
3941}
3942
3943impl EventEmitter<Event> for MultiBuffer {}
3944
3945impl MultiBufferSnapshot {
3946    pub fn text(&self) -> String {
3947        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3948            .map(|chunk| chunk.text)
3949            .collect()
3950    }
3951
3952    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3953        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3954            .flat_map(|c| c.chars().rev())
3955    }
3956
3957    fn reversed_chunks_in_range(
3958        &self,
3959        range: Range<MultiBufferOffset>,
3960    ) -> ReversedMultiBufferChunks<'_> {
3961        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3962        cursor.seek(&range.end);
3963        let current_chunks = cursor.region().as_ref().map(|region| {
3964            let start_overshoot = range.start.saturating_sub(region.range.start);
3965            let end_overshoot = range.end - region.range.start;
3966            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3967            let start = region.buffer_range.start + start_overshoot;
3968            region.buffer.reversed_chunks_in_range(start..end)
3969        });
3970        ReversedMultiBufferChunks {
3971            cursor,
3972            current_chunks,
3973            start: range.start,
3974            offset: range.end,
3975        }
3976    }
3977
3978    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3979        let offset = position.to_offset(self);
3980        self.text_for_range(offset..self.len())
3981            .flat_map(|chunk| chunk.chars())
3982    }
3983
3984    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3985        self.chunks(range, false).map(|chunk| chunk.text)
3986    }
3987
3988    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3989        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3990            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3991    }
3992
3993    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3994    where
3995        T: ToOffset,
3996    {
3997        let position = position.to_offset(self);
3998        position == self.clip_offset(position, Bias::Left)
3999            && self
4000                .bytes_in_range(position..self.len())
4001                .flatten()
4002                .copied()
4003                .take(needle.len())
4004                .eq(needle.bytes())
4005    }
4006
4007    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4008        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
4009    }
4010
4011    pub fn diff_hunks_in_range<T: ToPoint>(
4012        &self,
4013        range: Range<T>,
4014    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
4015        let query_range = range.start.to_point(self)..range.end.to_point(self);
4016        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
4017            let diff = self.diffs.get(&buffer.remote_id())?;
4018            let iter = if let Some(main_buffer) = &diff.main_buffer {
4019                let buffer_start = buffer.point_to_offset(buffer_range.start);
4020                let buffer_end = buffer.point_to_offset(buffer_range.end);
4021                itertools::Either::Left(
4022                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
4023                        .map(move |hunk| (hunk, buffer, true)),
4024                )
4025            } else {
4026                let buffer_start = buffer.anchor_before(buffer_range.start);
4027                let buffer_end = buffer.anchor_after(buffer_range.end);
4028                itertools::Either::Right(
4029                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
4030                        .map(move |hunk| (hunk, buffer, false)),
4031                )
4032            };
4033            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
4034                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
4035                    return None;
4036                }
4037                let range = if is_inverted {
4038                    hunk.diff_base_byte_range.to_point(&buffer)
4039                } else {
4040                    hunk.range.clone()
4041                };
4042                Some((range, (hunk, is_inverted)))
4043            }))
4044        })
4045        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4046            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4047            {
4048                return None;
4049            }
4050            let end_row = if range.end.column == 0 {
4051                range.end.row
4052            } else {
4053                range.end.row + 1
4054            };
4055
4056            let word_diffs =
4057                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4058                    .then(|| {
4059                        let mut word_diffs = Vec::new();
4060
4061                        if self.show_deleted_hunks || is_inverted {
4062                            let hunk_start_offset = if is_inverted {
4063                                Anchor::in_buffer(
4064                                    excerpt.id,
4065                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4066                                )
4067                                .to_offset(self)
4068                            } else {
4069                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4070                                    .to_offset(self)
4071                            };
4072
4073                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4074                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4075                            }));
4076                        }
4077
4078                        if !is_inverted {
4079                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4080                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4081                            }));
4082                        }
4083                        word_diffs
4084                    })
4085                    .unwrap_or_default();
4086
4087            let buffer_range = if is_inverted {
4088                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4089                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4090            } else {
4091                hunk.buffer_range.clone()
4092            };
4093            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4094                DiffHunkStatusKind::Deleted
4095            } else if hunk.diff_base_byte_range.is_empty() {
4096                DiffHunkStatusKind::Added
4097            } else {
4098                DiffHunkStatusKind::Modified
4099            };
4100            Some(MultiBufferDiffHunk {
4101                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4102                buffer_id: excerpt.buffer_id,
4103                excerpt_id: excerpt.id,
4104                buffer_range,
4105                word_diffs,
4106                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4107                    ..BufferOffset(hunk.diff_base_byte_range.end),
4108                status: DiffHunkStatus {
4109                    kind: status_kind,
4110                    secondary: hunk.secondary_status,
4111                },
4112            })
4113        })
4114    }
4115
4116    fn excerpts_for_range<T: ToOffset>(
4117        &self,
4118        range: Range<T>,
4119    ) -> impl Iterator<Item = &Excerpt> + '_ {
4120        let range = range.start.to_offset(self)..range.end.to_offset(self);
4121        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4122        cursor.seek(&range.start);
4123        std::iter::from_fn(move || {
4124            let region = cursor.region()?;
4125            if region.range.start > range.end
4126                || region.range.start == range.end && region.range.start > range.start
4127            {
4128                return None;
4129            }
4130            let excerpt = region.excerpt;
4131            cursor.next_excerpt_forwards();
4132            Some(excerpt)
4133        })
4134    }
4135
4136    pub fn excerpt_ids_for_range<T: ToOffset>(
4137        &self,
4138        range: Range<T>,
4139    ) -> impl Iterator<Item = ExcerptId> + '_ {
4140        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4141    }
4142
4143    pub fn buffer_ids_for_range<T: ToOffset>(
4144        &self,
4145        range: Range<T>,
4146    ) -> impl Iterator<Item = BufferId> + '_ {
4147        self.excerpts_for_range(range)
4148            .map(|excerpt| excerpt.buffer_id)
4149    }
4150
4151    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4152    ///
4153    /// The passed in anchors must be ordered.
4154    pub fn text_anchors_to_visible_anchors(
4155        &self,
4156        anchors: impl IntoIterator<Item = text::Anchor>,
4157    ) -> Vec<Option<Anchor>> {
4158        let anchors = anchors.into_iter();
4159        let mut result = Vec::with_capacity(anchors.size_hint().0);
4160        let mut anchors = anchors.peekable();
4161        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4162        'anchors: while let Some(anchor) = anchors.peek() {
4163            let Some(buffer_id) = anchor.buffer_id else {
4164                anchors.next();
4165                result.push(None);
4166                continue 'anchors;
4167            };
4168            let mut same_buffer_anchors =
4169                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4170
4171            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4172                let Some(mut next) = same_buffer_anchors.next() else {
4173                    continue 'anchors;
4174                };
4175                'excerpts: for locator in locators.iter() {
4176                    if cursor.seek_forward(&Some(locator), Bias::Left)
4177                        && let Some(excerpt) = cursor.item()
4178                    {
4179                        loop {
4180                            // anchor is before the first excerpt
4181                            if excerpt
4182                                .range
4183                                .context
4184                                .start
4185                                .cmp(&next, &excerpt.buffer)
4186                                .is_gt()
4187                            {
4188                                // so we skip it and try the next anchor
4189                                result.push(None);
4190                                match same_buffer_anchors.next() {
4191                                    Some(anchor) => next = anchor,
4192                                    None => continue 'anchors,
4193                                }
4194                            // anchor is within the excerpt
4195                            } else if excerpt
4196                                .range
4197                                .context
4198                                .end
4199                                .cmp(&next, &excerpt.buffer)
4200                                .is_ge()
4201                            {
4202                                // record it and all following anchors that are within
4203                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4204                                result.extend(
4205                                    same_buffer_anchors
4206                                        .peeking_take_while(|a| {
4207                                            excerpt
4208                                                .range
4209                                                .context
4210                                                .end
4211                                                .cmp(a, &excerpt.buffer)
4212                                                .is_ge()
4213                                        })
4214                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4215                                );
4216                                match same_buffer_anchors.next() {
4217                                    Some(anchor) => next = anchor,
4218                                    None => continue 'anchors,
4219                                }
4220                            // anchor is after the excerpt, try the next one
4221                            } else {
4222                                continue 'excerpts;
4223                            }
4224                        }
4225                    }
4226                }
4227                // account for `next`
4228                result.push(None);
4229            }
4230            result.extend(same_buffer_anchors.map(|_| None));
4231        }
4232
4233        result
4234    }
4235
4236    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4237        &self,
4238        ranges: impl Iterator<Item = Range<T>>,
4239    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4240        ranges.flat_map(|range| {
4241            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4242                .into_iter()
4243        })
4244    }
4245
4246    pub fn range_to_buffer_ranges<R, T>(
4247        &self,
4248        range: R,
4249    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4250    where
4251        R: RangeBounds<T>,
4252        T: ToOffset,
4253    {
4254        self.range_to_buffer_ranges_with_context(range)
4255            .into_iter()
4256            .map(|(buffer, range, id, _context)| (buffer, range, id))
4257            .collect()
4258    }
4259
4260    pub fn range_to_buffer_ranges_with_context<R, T>(
4261        &self,
4262        range: R,
4263    ) -> Vec<(
4264        &BufferSnapshot,
4265        Range<BufferOffset>,
4266        ExcerptId,
4267        Range<text::Anchor>,
4268    )>
4269    where
4270        R: RangeBounds<T>,
4271        T: ToOffset,
4272    {
4273        let start = match range.start_bound() {
4274            Bound::Included(start) => start.to_offset(self),
4275            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4276            Bound::Unbounded => MultiBufferOffset::ZERO,
4277        };
4278        let end_bound = match range.end_bound() {
4279            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4280            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4281            Bound::Unbounded => Bound::Unbounded,
4282        };
4283        let bounds = (Bound::Included(start), end_bound);
4284
4285        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4286        cursor.seek(&start);
4287
4288        let mut result: Vec<(
4289            &BufferSnapshot,
4290            Range<BufferOffset>,
4291            ExcerptId,
4292            Range<text::Anchor>,
4293        )> = Vec::new();
4294        while let Some(region) = cursor.region() {
4295            let dominated_by_end_bound = match end_bound {
4296                Bound::Included(end) => region.range.start > end,
4297                Bound::Excluded(end) => region.range.start >= end,
4298                Bound::Unbounded => false,
4299            };
4300            if dominated_by_end_bound {
4301                break;
4302            }
4303            if region.is_main_buffer {
4304                let start_overshoot = start.saturating_sub(region.range.start);
4305                let end_offset = match end_bound {
4306                    Bound::Included(end) | Bound::Excluded(end) => end,
4307                    Bound::Unbounded => region.range.end,
4308                };
4309                let end_overshoot = end_offset.saturating_sub(region.range.start);
4310                let start = region
4311                    .buffer_range
4312                    .end
4313                    .min(region.buffer_range.start + start_overshoot);
4314                let end = region
4315                    .buffer_range
4316                    .end
4317                    .min(region.buffer_range.start + end_overshoot);
4318                let context = region.excerpt.range.context.clone();
4319                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4320                    *excerpt_id == region.excerpt.id && prev_range.end == start
4321                }) {
4322                    prev.1.end = end;
4323                } else {
4324                    result.push((region.buffer, start..end, region.excerpt.id, context));
4325                }
4326            }
4327            cursor.next();
4328        }
4329
4330        if let Some(excerpt) = cursor.excerpt() {
4331            let dominated_by_prev_excerpt =
4332                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4333            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4334                let excerpt_position = self.len();
4335                if bounds.contains(&excerpt_position) {
4336                    let buffer_offset =
4337                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4338                    let context = excerpt.range.context.clone();
4339                    result.push((
4340                        &excerpt.buffer,
4341                        buffer_offset..buffer_offset,
4342                        excerpt.id,
4343                        context,
4344                    ));
4345                }
4346            }
4347        }
4348
4349        result
4350    }
4351
4352    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4353        &self,
4354        range: Range<T>,
4355    ) -> impl Iterator<
4356        Item = (
4357            &BufferSnapshot,
4358            Range<BufferOffset>,
4359            ExcerptId,
4360            Option<Anchor>,
4361        ),
4362    > + '_ {
4363        let start = range.start.to_offset(self);
4364        let end = range.end.to_offset(self);
4365
4366        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4367        cursor.seek(&start);
4368
4369        std::iter::from_fn(move || {
4370            let region = cursor.region()?;
4371            if region.range.start > end {
4372                return None;
4373            }
4374            let start_overshoot = start.saturating_sub(region.range.start);
4375            let end_overshoot = end.saturating_sub(region.range.start);
4376            let start = region
4377                .buffer_range
4378                .end
4379                .min(region.buffer_range.start + start_overshoot);
4380            let end = region
4381                .buffer_range
4382                .end
4383                .min(region.buffer_range.start + end_overshoot);
4384
4385            let region_excerpt_id = region.excerpt.id;
4386            let deleted_hunk_anchor = if region.is_main_buffer {
4387                None
4388            } else {
4389                Some(self.anchor_before(region.range.start))
4390            };
4391            let result = (
4392                region.buffer,
4393                start..end,
4394                region_excerpt_id,
4395                deleted_hunk_anchor,
4396            );
4397            cursor.next();
4398            Some(result)
4399        })
4400    }
4401
4402    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4403    /// coordinates.
4404    ///
4405    /// The given callback will be called for every excerpt intersecting the given range. It will
4406    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4407    /// The callback should return an iterator of metadata items from that buffer, each paired
4408    /// with a buffer range.
4409    ///
4410    /// The returned iterator yields each of these metadata items, paired with its range in
4411    /// multi-buffer coordinates.
4412    fn lift_buffer_metadata<'a, MBD, M, I>(
4413        &'a self,
4414        query_range: Range<MBD>,
4415        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4416    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4417    where
4418        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4419        MBD: MultiBufferDimension
4420            + Ord
4421            + Sub<Output = MBD::TextDimension>
4422            + ops::Add<MBD::TextDimension, Output = MBD>
4423            + ops::AddAssign<MBD::TextDimension>,
4424        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4425            + ops::Add<Output = MBD::TextDimension>
4426            + AddAssign<MBD::TextDimension>
4427            + Ord,
4428    {
4429        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4430        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4431
4432        // Find the excerpt and buffer offset where the given range ends.
4433        cursor.seek(&query_range.end);
4434        let mut range_end = None;
4435        while let Some(region) = cursor.region() {
4436            if region.is_main_buffer {
4437                let mut buffer_end = region.buffer_range.start;
4438                let overshoot = if query_range.end > region.range.start {
4439                    query_range.end - region.range.start
4440                } else {
4441                    <MBD::TextDimension>::default()
4442                };
4443                buffer_end = buffer_end + overshoot;
4444                range_end = Some((region.excerpt.id, buffer_end));
4445                break;
4446            }
4447            cursor.next();
4448        }
4449
4450        cursor.seek(&query_range.start);
4451
4452        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4453            && region.range.start > MBD::default()
4454        {
4455            cursor.prev()
4456        } else if let Some(region) = cursor.region()
4457            && region.is_main_buffer
4458            && region.diff_hunk_status.is_some()
4459        {
4460            cursor.prev();
4461            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4462                cursor.next();
4463            }
4464        }
4465
4466        iter::from_fn(move || {
4467            loop {
4468                let excerpt = cursor.excerpt()?;
4469
4470                // If we have already retrieved metadata for this excerpt, continue to use it.
4471                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4472                    .as_mut()
4473                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4474                {
4475                    Some(metadata)
4476                }
4477                // Otherwise, compute the intersection of the input range with the excerpt's range,
4478                // and retrieve the metadata for the resulting range.
4479                else {
4480                    let region = cursor.region()?;
4481                    let mut buffer_start;
4482                    if region.is_main_buffer {
4483                        buffer_start = region.buffer_range.start;
4484                        if query_range.start > region.range.start {
4485                            let overshoot = query_range.start - region.range.start;
4486                            buffer_start = buffer_start + overshoot;
4487                        }
4488                        buffer_start = buffer_start.min(region.buffer_range.end);
4489                    } else {
4490                        buffer_start = cursor.main_buffer_position()?;
4491                    };
4492                    let mut buffer_end = excerpt
4493                        .range
4494                        .context
4495                        .end
4496                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4497                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4498                        && excerpt.id == end_excerpt_id
4499                    {
4500                        buffer_end = buffer_end.min(end_buffer_offset);
4501                    }
4502
4503                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4504                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4505                    })
4506                };
4507
4508                // Visit each metadata item.
4509                if let Some((metadata_buffer_range, metadata)) =
4510                    metadata_iter.and_then(Iterator::next)
4511                {
4512                    // Find the multibuffer regions that contain the start and end of
4513                    // the metadata item's range.
4514                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4515                        while let Some(region) = cursor.region() {
4516                            if (region.is_main_buffer
4517                                && (region.buffer_range.end >= metadata_buffer_range.start
4518                                    || cursor.is_at_end_of_excerpt()))
4519                                || (!region.is_main_buffer
4520                                    && region.buffer_range.start == metadata_buffer_range.start)
4521                            {
4522                                break;
4523                            }
4524                            cursor.next();
4525                        }
4526                    }
4527                    let start_region = cursor.region()?.clone();
4528                    while let Some(region) = cursor.region() {
4529                        if region.is_main_buffer
4530                            && (region.buffer_range.end > metadata_buffer_range.end
4531                                || cursor.is_at_end_of_excerpt())
4532                        {
4533                            break;
4534                        }
4535                        cursor.next();
4536                    }
4537                    let end_region = cursor.region();
4538
4539                    // Convert the metadata item's range into multibuffer coordinates.
4540                    let mut start_position = start_region.range.start;
4541                    let region_buffer_start = start_region.buffer_range.start;
4542                    if start_region.is_main_buffer
4543                        && metadata_buffer_range.start > region_buffer_start
4544                    {
4545                        start_position =
4546                            start_position + (metadata_buffer_range.start - region_buffer_start);
4547                        start_position = start_position.min(start_region.range.end);
4548                    }
4549
4550                    let mut end_position = self.max_position();
4551                    if let Some(end_region) = &end_region {
4552                        end_position = end_region.range.start;
4553                        debug_assert!(end_region.is_main_buffer);
4554                        let region_buffer_start = end_region.buffer_range.start;
4555                        if metadata_buffer_range.end > region_buffer_start {
4556                            end_position =
4557                                end_position + (metadata_buffer_range.end - region_buffer_start);
4558                        }
4559                        end_position = end_position.min(end_region.range.end);
4560                    }
4561
4562                    if start_position <= query_range.end && end_position >= query_range.start {
4563                        return Some((start_position..end_position, metadata, excerpt));
4564                    }
4565                }
4566                // When there are no more metadata items for this excerpt, move to the next excerpt.
4567                else {
4568                    current_excerpt_metadata.take();
4569                    if let Some((end_excerpt_id, _)) = range_end
4570                        && excerpt.id == end_excerpt_id
4571                    {
4572                        return None;
4573                    }
4574                    cursor.next_excerpt_forwards();
4575                }
4576            }
4577        })
4578    }
4579
4580    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4581        let offset = position.to_offset(self);
4582
4583        let mut cursor = self
4584            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4585            );
4586        cursor.seek(&DimensionPair {
4587            key: offset,
4588            value: None,
4589        });
4590        cursor.seek_to_start_of_current_excerpt();
4591        let excerpt = cursor.excerpt()?;
4592
4593        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4594        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4595        let current_position = self
4596            .anchor_before(offset)
4597            .text_anchor
4598            .to_offset(&excerpt.buffer);
4599
4600        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4601            if let Some(main_buffer) = &diff.main_buffer {
4602                for hunk in diff
4603                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4604                {
4605                    if hunk.diff_base_byte_range.end >= current_position {
4606                        continue;
4607                    }
4608                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4609                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4610                    return Some(MultiBufferRow(start.row));
4611                }
4612            } else {
4613                let excerpt_end = excerpt
4614                    .buffer
4615                    .anchor_before(excerpt_end.min(current_position));
4616                for hunk in diff.hunks_intersecting_range_rev(
4617                    excerpt.range.context.start..excerpt_end,
4618                    &excerpt.buffer,
4619                ) {
4620                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4621                    if hunk_end >= current_position {
4622                        continue;
4623                    }
4624                    let start =
4625                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4626                    return Some(MultiBufferRow(start.row));
4627                }
4628            }
4629        }
4630
4631        loop {
4632            cursor.prev_excerpt();
4633            let excerpt = cursor.excerpt()?;
4634
4635            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4636                continue;
4637            };
4638            if let Some(main_buffer) = &diff.main_buffer {
4639                let Some(hunk) = diff
4640                    .hunks_intersecting_base_text_range_rev(
4641                        excerpt.range.context.to_offset(&excerpt.buffer),
4642                        main_buffer,
4643                    )
4644                    .next()
4645                else {
4646                    continue;
4647                };
4648                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4649                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4650                return Some(MultiBufferRow(start.row));
4651            } else {
4652                let Some(hunk) = diff
4653                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4654                    .next()
4655                else {
4656                    continue;
4657                };
4658                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4659                return Some(MultiBufferRow(start.row));
4660            }
4661        }
4662    }
4663
4664    pub fn has_diff_hunks(&self) -> bool {
4665        self.diffs.values().any(|diff| !diff.is_empty())
4666    }
4667
4668    pub fn is_inside_word<T: ToOffset>(
4669        &self,
4670        position: T,
4671        scope_context: Option<CharScopeContext>,
4672    ) -> bool {
4673        let position = position.to_offset(self);
4674        let classifier = self
4675            .char_classifier_at(position)
4676            .scope_context(scope_context);
4677        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4678        let prev_char_kind = self
4679            .reversed_chars_at(position)
4680            .next()
4681            .map(|c| classifier.kind(c));
4682        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4683    }
4684
4685    pub fn surrounding_word<T: ToOffset>(
4686        &self,
4687        start: T,
4688        scope_context: Option<CharScopeContext>,
4689    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4690        let mut start = start.to_offset(self);
4691        let mut end = start;
4692        let mut next_chars = self.chars_at(start).peekable();
4693        let mut prev_chars = self.reversed_chars_at(start).peekable();
4694
4695        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4696
4697        let word_kind = cmp::max(
4698            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4699            next_chars.peek().copied().map(|c| classifier.kind(c)),
4700        );
4701
4702        for ch in prev_chars {
4703            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4704                start -= ch.len_utf8();
4705            } else {
4706                break;
4707            }
4708        }
4709
4710        for ch in next_chars {
4711            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4712                end += ch.len_utf8();
4713            } else {
4714                break;
4715            }
4716        }
4717
4718        (start..end, word_kind)
4719    }
4720
4721    pub fn char_kind_before<T: ToOffset>(
4722        &self,
4723        start: T,
4724        scope_context: Option<CharScopeContext>,
4725    ) -> Option<CharKind> {
4726        let start = start.to_offset(self);
4727        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4728        self.reversed_chars_at(start)
4729            .next()
4730            .map(|ch| classifier.kind(ch))
4731    }
4732
4733    pub fn is_singleton(&self) -> bool {
4734        self.singleton
4735    }
4736
4737    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4738        if self.singleton {
4739            self.excerpts
4740                .iter()
4741                .next()
4742                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4743        } else {
4744            None
4745        }
4746    }
4747
4748    pub fn len(&self) -> MultiBufferOffset {
4749        self.diff_transforms.summary().output.len
4750    }
4751
4752    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4753        MBD::from_summary(&self.text_summary())
4754    }
4755
4756    pub fn is_empty(&self) -> bool {
4757        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4758    }
4759
4760    pub fn widest_line_number(&self) -> u32 {
4761        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4762        self.excerpts.summary().widest_line_number + 1
4763    }
4764
4765    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4766        let range = range.start.to_offset(self)..range.end.to_offset(self);
4767        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4768        excerpts.seek(&range.start);
4769
4770        let mut chunk;
4771        let mut has_trailing_newline;
4772        let excerpt_bytes;
4773        if let Some(region) = excerpts.region() {
4774            let mut bytes = region.buffer.bytes_in_range(
4775                region.buffer_range.start + (range.start - region.range.start)
4776                    ..(region.buffer_range.start + (range.end - region.range.start))
4777                        .min(region.buffer_range.end),
4778            );
4779            chunk = bytes.next().unwrap_or(&[][..]);
4780            excerpt_bytes = Some(bytes);
4781            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4782            if chunk.is_empty() && has_trailing_newline {
4783                chunk = b"\n";
4784                has_trailing_newline = false;
4785            }
4786        } else {
4787            chunk = &[][..];
4788            excerpt_bytes = None;
4789            has_trailing_newline = false;
4790        };
4791
4792        MultiBufferBytes {
4793            range,
4794            cursor: excerpts,
4795            excerpt_bytes,
4796            has_trailing_newline,
4797            chunk,
4798        }
4799    }
4800
4801    pub fn reversed_bytes_in_range<T: ToOffset>(
4802        &self,
4803        range: Range<T>,
4804    ) -> ReversedMultiBufferBytes<'_> {
4805        let range = range.start.to_offset(self)..range.end.to_offset(self);
4806        let mut chunks = self.reversed_chunks_in_range(range.clone());
4807        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4808        ReversedMultiBufferBytes {
4809            range,
4810            chunks,
4811            chunk,
4812        }
4813    }
4814
4815    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4816        let mut cursor = self.cursor::<Point, Point>();
4817        cursor.seek(&Point::new(start_row.0, 0));
4818        let mut result = MultiBufferRows {
4819            point: Point::new(0, 0),
4820            is_empty: self.excerpts.is_empty(),
4821            is_singleton: self.is_singleton(),
4822            cursor,
4823        };
4824        result.seek(start_row);
4825        result
4826    }
4827
4828    pub fn chunks<T: ToOffset>(
4829        &self,
4830        range: Range<T>,
4831        language_aware: bool,
4832    ) -> MultiBufferChunks<'_> {
4833        let mut chunks = MultiBufferChunks {
4834            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4835                ..ExcerptDimension(MultiBufferOffset::ZERO),
4836            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4837            excerpts: self.excerpts.cursor(()),
4838            diff_transforms: self.diff_transforms.cursor(()),
4839            diffs: &self.diffs,
4840            diff_base_chunks: None,
4841            excerpt_chunks: None,
4842            buffer_chunk: None,
4843            language_aware,
4844        };
4845        let range = range.start.to_offset(self)..range.end.to_offset(self);
4846        chunks.seek(range);
4847        chunks
4848    }
4849
4850    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4851        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4852    }
4853
4854    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4855        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4856    }
4857
4858    pub fn clip_offset_utf16(
4859        &self,
4860        offset: MultiBufferOffsetUtf16,
4861        bias: Bias,
4862    ) -> MultiBufferOffsetUtf16 {
4863        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4864    }
4865
4866    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4867        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4868            buffer.clip_point_utf16(Unclipped(point), bias)
4869        })
4870    }
4871
4872    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4873        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4874    }
4875
4876    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4877        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4878    }
4879
4880    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4881        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4882    }
4883
4884    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4885        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4886    }
4887
4888    #[instrument(skip_all)]
4889    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4890        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4891    }
4892
4893    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4894        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4895    }
4896
4897    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4898        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4899    }
4900
4901    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4902        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4903    }
4904
4905    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4906        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4907    }
4908
4909    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4910        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4911    }
4912
4913    fn clip_dimension<MBD, BD>(
4914        &self,
4915        position: MBD,
4916        bias: Bias,
4917        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4918    ) -> MBD
4919    where
4920        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4921        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4922    {
4923        let mut cursor = self.cursor::<MBD, BD>();
4924        cursor.seek(&position);
4925        if let Some(region) = cursor.region() {
4926            if position >= region.range.end {
4927                return region.range.end;
4928            }
4929            let overshoot = position - region.range.start;
4930            let mut buffer_position = region.buffer_range.start;
4931            buffer_position += overshoot;
4932            let clipped_buffer_position =
4933                clip_buffer_position(region.buffer, buffer_position, bias);
4934            let mut position = region.range.start;
4935            position += clipped_buffer_position - region.buffer_range.start;
4936            position
4937        } else {
4938            self.max_position()
4939        }
4940    }
4941
4942    #[instrument(skip_all)]
4943    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4944        &self,
4945        key: MBR1,
4946        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4947    ) -> MBR2
4948    where
4949        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4950        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4951        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4952        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4953    {
4954        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4955        cursor.seek(&DimensionPair { key, value: None });
4956        if let Some(region) = cursor.region() {
4957            if key >= region.range.end.key {
4958                return region.range.end.value.unwrap();
4959            }
4960            let start_key = region.range.start.key;
4961            let start_value = region.range.start.value.unwrap();
4962            let buffer_start_key = region.buffer_range.start.key;
4963            let buffer_start_value = region.buffer_range.start.value.unwrap();
4964            let mut buffer_key = buffer_start_key;
4965            buffer_key += key - start_key;
4966            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4967            let mut result = start_value;
4968            result += buffer_value - buffer_start_value;
4969            result
4970        } else {
4971            self.max_position()
4972        }
4973    }
4974
4975    pub fn point_to_buffer_offset<T: ToOffset>(
4976        &self,
4977        point: T,
4978    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4979        let offset = point.to_offset(self);
4980        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4981        cursor.seek(&offset);
4982        let region = cursor.region()?;
4983        let overshoot = offset - region.range.start;
4984        let buffer_offset = region.buffer_range.start + overshoot;
4985        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4986            && region.has_trailing_newline
4987            && !region.is_main_buffer
4988        {
4989            let main_buffer_position = cursor.main_buffer_position()?;
4990            let buffer_snapshot = &cursor.excerpt()?.buffer;
4991            return Some((buffer_snapshot, main_buffer_position));
4992        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4993            return None;
4994        }
4995        Some((region.buffer, buffer_offset))
4996    }
4997
4998    pub fn point_to_buffer_point(
4999        &self,
5000        point: Point,
5001    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
5002        let mut cursor = self.cursor::<Point, Point>();
5003        cursor.seek(&point);
5004        let region = cursor.region()?;
5005        let overshoot = point - region.range.start;
5006        let buffer_point = region.buffer_range.start + overshoot;
5007        let excerpt = cursor.excerpt()?;
5008        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
5009            && region.has_trailing_newline
5010            && !region.is_main_buffer
5011        {
5012            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
5013        } else if buffer_point > region.buffer.max_point() {
5014            return None;
5015        }
5016        Some((region.buffer, buffer_point, excerpt.id))
5017    }
5018
5019    pub fn suggested_indents(
5020        &self,
5021        rows: impl IntoIterator<Item = u32>,
5022        cx: &App,
5023    ) -> BTreeMap<MultiBufferRow, IndentSize> {
5024        let mut result = BTreeMap::new();
5025        self.suggested_indents_callback(
5026            rows,
5027            &mut |row, indent| {
5028                result.insert(row, indent);
5029                ControlFlow::Continue(())
5030            },
5031            cx,
5032        );
5033        result
5034    }
5035
5036    // move this to be a generator once those are a thing
5037    pub fn suggested_indents_callback(
5038        &self,
5039        rows: impl IntoIterator<Item = u32>,
5040        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
5041        cx: &App,
5042    ) {
5043        let mut rows_for_excerpt = Vec::new();
5044        let mut cursor = self.cursor::<Point, Point>();
5045        let mut rows = rows.into_iter().peekable();
5046        let mut prev_row = u32::MAX;
5047        let mut prev_language_indent_size = IndentSize::default();
5048
5049        while let Some(row) = rows.next() {
5050            cursor.seek(&Point::new(row, 0));
5051            let Some(region) = cursor.region() else {
5052                continue;
5053            };
5054
5055            // Retrieve the language and indent size once for each disjoint region being indented.
5056            let single_indent_size = if row.saturating_sub(1) == prev_row {
5057                prev_language_indent_size
5058            } else {
5059                region
5060                    .buffer
5061                    .language_indent_size_at(Point::new(row, 0), cx)
5062            };
5063            prev_language_indent_size = single_indent_size;
5064            prev_row = row;
5065
5066            let start_buffer_row = region.buffer_range.start.row;
5067            let start_multibuffer_row = region.range.start.row;
5068            let end_multibuffer_row = region.range.end.row;
5069
5070            rows_for_excerpt.push(row);
5071            while let Some(next_row) = rows.peek().copied() {
5072                if end_multibuffer_row > next_row {
5073                    rows_for_excerpt.push(next_row);
5074                    rows.next();
5075                } else {
5076                    break;
5077                }
5078            }
5079
5080            let buffer_rows = rows_for_excerpt
5081                .drain(..)
5082                .map(|row| start_buffer_row + row - start_multibuffer_row);
5083            let buffer_indents = region
5084                .buffer
5085                .suggested_indents(buffer_rows, single_indent_size);
5086            for (row, indent) in buffer_indents {
5087                if cb(
5088                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5089                    indent,
5090                )
5091                .is_break()
5092                {
5093                    return;
5094                }
5095            }
5096        }
5097    }
5098
5099    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5100        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5101            let mut size = buffer.indent_size_for_line(range.start.row);
5102            size.len = size
5103                .len
5104                .min(range.end.column)
5105                .saturating_sub(range.start.column);
5106            size
5107        } else {
5108            IndentSize::spaces(0)
5109        }
5110    }
5111
5112    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5113        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5114            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5115        } else {
5116            LineIndent::spaces(0)
5117        }
5118    }
5119
5120    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5121        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5122
5123        if self.language_settings(cx).extend_comment_on_newline
5124            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5125        {
5126            let delimiters = language_scope.line_comment_prefixes();
5127            for delimiter in delimiters {
5128                if *self
5129                    .chars_at(Point::new(row.0, indent.len() as u32))
5130                    .take(delimiter.chars().count())
5131                    .collect::<String>()
5132                    .as_str()
5133                    == **delimiter
5134                {
5135                    indent.push_str(delimiter);
5136                    break;
5137                }
5138            }
5139        }
5140
5141        indent
5142    }
5143
5144    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5145    where
5146        T: ToOffset,
5147    {
5148        for char in self.reversed_chars_at(position) {
5149            if !char.is_whitespace() {
5150                return false;
5151            }
5152            if char == '\n' {
5153                return true;
5154            }
5155        }
5156        true
5157    }
5158
5159    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5160        while row.0 > 0 {
5161            row.0 -= 1;
5162            if !self.is_line_blank(row) {
5163                return Some(row);
5164            }
5165        }
5166        None
5167    }
5168
5169    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5170        if let Some((_, range)) = self.buffer_line_for_row(row) {
5171            range.end.column - range.start.column
5172        } else {
5173            0
5174        }
5175    }
5176
5177    pub fn buffer_line_for_row(
5178        &self,
5179        row: MultiBufferRow,
5180    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5181        let mut cursor = self.cursor::<Point, Point>();
5182        let point = Point::new(row.0, 0);
5183        cursor.seek(&point);
5184        let region = cursor.region()?;
5185        let overshoot = point.min(region.range.end) - region.range.start;
5186        let buffer_point = region.buffer_range.start + overshoot;
5187        if buffer_point.row > region.buffer_range.end.row {
5188            return None;
5189        }
5190        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5191        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5192            .min(region.buffer_range.end);
5193        Some((region.buffer, line_start..line_end))
5194    }
5195
5196    pub fn max_point(&self) -> Point {
5197        self.text_summary().lines
5198    }
5199
5200    pub fn max_row(&self) -> MultiBufferRow {
5201        MultiBufferRow(self.text_summary().lines.row)
5202    }
5203
5204    pub fn text_summary(&self) -> MBTextSummary {
5205        self.diff_transforms.summary().output
5206    }
5207
5208    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5209    where
5210        MBD: MultiBufferDimension + AddAssign,
5211        O: ToOffset,
5212    {
5213        let range = range.start.to_offset(self)..range.end.to_offset(self);
5214        let mut cursor = self
5215            .diff_transforms
5216            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5217        cursor.seek(&range.start, Bias::Right);
5218
5219        let Some(first_transform) = cursor.item() else {
5220            return MBD::from_summary(&MBTextSummary::default());
5221        };
5222
5223        let diff_transform_start = cursor.start().0;
5224        let diff_transform_end = cursor.end().0;
5225        let diff_start = range.start;
5226        let start_overshoot = diff_start - diff_transform_start;
5227        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5228
5229        let mut result = match first_transform {
5230            DiffTransform::BufferContent { .. } => {
5231                let excerpt_start = cursor.start().1 + start_overshoot;
5232                let excerpt_end = cursor.start().1 + end_overshoot;
5233                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5234            }
5235            DiffTransform::DeletedHunk {
5236                buffer_id,
5237                base_text_byte_range,
5238                has_trailing_newline,
5239                ..
5240            } => {
5241                let buffer_start = base_text_byte_range.start + start_overshoot;
5242                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5243                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5244                    panic!("{:?} is in non-existent deleted hunk", range.start)
5245                };
5246
5247                let include_trailing_newline =
5248                    *has_trailing_newline && range.end >= diff_transform_end;
5249                if include_trailing_newline {
5250                    buffer_end -= 1;
5251                }
5252
5253                let mut summary = base_text
5254                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5255
5256                if include_trailing_newline {
5257                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5258                        &TextSummary::newline(),
5259                    ))
5260                }
5261
5262                let mut result = MBD::default();
5263                result.add_text_dim(&summary);
5264                result
5265            }
5266        };
5267        if range.end < diff_transform_end {
5268            return result;
5269        }
5270
5271        cursor.next();
5272        result.add_mb_text_summary(
5273            &cursor
5274                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5275                .0,
5276        );
5277
5278        let Some(last_transform) = cursor.item() else {
5279            return result;
5280        };
5281
5282        let overshoot = range.end - cursor.start().0;
5283        let suffix = match last_transform {
5284            DiffTransform::BufferContent { .. } => {
5285                let end = cursor.start().1 + overshoot;
5286                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5287            }
5288            DiffTransform::DeletedHunk {
5289                base_text_byte_range,
5290                buffer_id,
5291                has_trailing_newline,
5292                ..
5293            } => {
5294                let buffer_end = base_text_byte_range.start + overshoot;
5295                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5296                    panic!("{:?} is in non-existent deleted hunk", range.end)
5297                };
5298
5299                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5300                    base_text_byte_range.start..buffer_end,
5301                );
5302                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5303                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5304                        &TextSummary::from("\n"),
5305                    ))
5306                }
5307
5308                let mut result = MBD::default();
5309                result.add_text_dim(&suffix);
5310                result
5311            }
5312        };
5313
5314        result += suffix;
5315        result
5316    }
5317
5318    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5319    where
5320        MBD: MultiBufferDimension + AddAssign,
5321    {
5322        let mut summary = MBD::default();
5323        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5324        cursor.seek(&range.start, Bias::Right);
5325        if let Some(excerpt) = cursor.item() {
5326            let mut end_before_newline = cursor.end();
5327            if excerpt.has_trailing_newline {
5328                end_before_newline -= 1;
5329            }
5330
5331            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5332            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5333            let end_in_excerpt =
5334                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5335            summary.add_text_dim(
5336                &excerpt
5337                    .buffer
5338                    .text_summary_for_range::<MBD::TextDimension, _>(
5339                        start_in_excerpt..end_in_excerpt,
5340                    ),
5341            );
5342
5343            if range.end > end_before_newline {
5344                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5345            }
5346
5347            cursor.next();
5348        }
5349
5350        if range.end > *cursor.start() {
5351            summary += cursor
5352                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5353                .0;
5354            if let Some(excerpt) = cursor.item() {
5355                range.end = cmp::max(*cursor.start(), range.end);
5356
5357                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5358                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5359                summary.add_text_dim(
5360                    &excerpt
5361                        .buffer
5362                        .text_summary_for_range::<MBD::TextDimension, _>(
5363                            excerpt_start..end_in_excerpt,
5364                        ),
5365                );
5366            }
5367        }
5368
5369        summary
5370    }
5371
5372    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5373    where
5374        MBD: MultiBufferDimension
5375            + Ord
5376            + Sub<Output = MBD::TextDimension>
5377            + Sub<MBD::TextDimension, Output = MBD>
5378            + AddAssign<MBD::TextDimension>
5379            + Add<MBD::TextDimension, Output = MBD>,
5380        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5381    {
5382        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5383        let locator = self.excerpt_locator_for_id(excerpt_id);
5384        let (start, _, mut item) = self
5385            .excerpts
5386            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5387        let mut start = MBD::from_summary(&start.text);
5388        if item.is_none() && excerpt_id == ExcerptId::max() {
5389            item = self.excerpts.last();
5390            if let Some(last_summary) = self.excerpts.last_summary() {
5391                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5392            }
5393        }
5394
5395        let excerpt_start_position = ExcerptDimension(start);
5396        if self.diff_transforms.is_empty() {
5397            if let Some(excerpt) = item {
5398                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5399                    return excerpt_start_position.0;
5400                }
5401                let excerpt_buffer_start = excerpt
5402                    .range
5403                    .context
5404                    .start
5405                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5406                let excerpt_buffer_end = excerpt
5407                    .range
5408                    .context
5409                    .end
5410                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5411                let buffer_summary = anchor
5412                    .text_anchor
5413                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5414                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5415                let mut position = excerpt_start_position;
5416                if summary > excerpt_buffer_start {
5417                    position += summary - excerpt_buffer_start;
5418                }
5419
5420                position.0
5421            } else {
5422                excerpt_start_position.0
5423            }
5424        } else {
5425            let mut diff_transforms_cursor = self
5426                .diff_transforms
5427                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5428            diff_transforms_cursor.next();
5429
5430            if let Some(excerpt) = item {
5431                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5432                    return self.resolve_summary_for_min_or_max_anchor(
5433                        &Anchor::min(),
5434                        excerpt_start_position,
5435                        &mut diff_transforms_cursor,
5436                    );
5437                }
5438                let excerpt_buffer_start = excerpt
5439                    .range
5440                    .context
5441                    .start
5442                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5443                let excerpt_buffer_end = excerpt
5444                    .range
5445                    .context
5446                    .end
5447                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5448                let buffer_summary = anchor
5449                    .text_anchor
5450                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5451                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5452                let mut position = excerpt_start_position;
5453                if summary > excerpt_buffer_start {
5454                    position += summary - excerpt_buffer_start;
5455                }
5456
5457                if diff_transforms_cursor.start().0 < position {
5458                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5459                }
5460                self.resolve_summary_for_anchor(
5461                    &anchor,
5462                    position,
5463                    &mut diff_transforms_cursor,
5464                    &excerpt.buffer,
5465                )
5466            } else {
5467                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5468                self.resolve_summary_for_min_or_max_anchor(
5469                    &Anchor::max(),
5470                    excerpt_start_position,
5471                    &mut diff_transforms_cursor,
5472                )
5473            }
5474        }
5475    }
5476
5477    /// Maps an anchor's excerpt-space position to its output-space position by
5478    /// walking the diff transforms. The cursor is shared across consecutive
5479    /// calls, so it may already be partway through the transform list.
5480    fn resolve_summary_for_anchor<MBD>(
5481        &self,
5482        anchor: &Anchor,
5483        excerpt_position: ExcerptDimension<MBD>,
5484        diff_transforms: &mut Cursor<
5485            DiffTransform,
5486            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5487        >,
5488        excerpt_buffer: &text::BufferSnapshot,
5489    ) -> MBD
5490    where
5491        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5492    {
5493        loop {
5494            let transform_end_position = diff_transforms.end().0;
5495            let item = diff_transforms.item();
5496            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5497
5498            // A right-biased anchor at a transform boundary belongs to the
5499            // *next* transform, so advance past the current one.
5500            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5501                diff_transforms.next();
5502                continue;
5503            }
5504
5505            let mut position = diff_transforms.start().1;
5506            match item {
5507                Some(DiffTransform::DeletedHunk {
5508                    buffer_id,
5509                    base_text_byte_range,
5510                    hunk_info,
5511                    ..
5512                }) => {
5513                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5514                        && let Some(base_text) =
5515                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5516                        && diff_base_anchor.is_valid(&base_text)
5517                    {
5518                        // The anchor carries a diff-base position — resolve it
5519                        // to a location inside the deleted hunk.
5520                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5521                        if base_text_offset >= base_text_byte_range.start
5522                            && base_text_offset <= base_text_byte_range.end
5523                        {
5524                            let position_in_hunk = base_text
5525                                .text_summary_for_range::<MBD::TextDimension, _>(
5526                                    base_text_byte_range.start..base_text_offset,
5527                                );
5528                            position.0.add_text_dim(&position_in_hunk);
5529                        } else if at_transform_end {
5530                            // diff_base offset falls outside this hunk's range;
5531                            // advance to see if the next transform is a better fit.
5532                            diff_transforms.next();
5533                            continue;
5534                        }
5535                    } else if at_transform_end
5536                        && anchor
5537                            .text_anchor
5538                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5539                            .is_gt()
5540                    {
5541                        // The anchor has no (valid) diff-base position, so it
5542                        // belongs in the buffer content, not in the deleted
5543                        // hunk. However, after an edit deletes the text between
5544                        // the hunk boundary and this anchor, both resolve to
5545                        // the same excerpt_position—landing us here on the
5546                        // DeletedHunk left behind by the shared cursor. Use the
5547                        // CRDT ordering to detect that the anchor is strictly
5548                        // *past* the hunk boundary and skip to the following
5549                        // BufferContent.
5550                        diff_transforms.next();
5551                        continue;
5552                    }
5553                }
5554                _ => {
5555                    // On a BufferContent (or no transform). If the anchor
5556                    // carries a diff_base_anchor it needs a DeletedHunk, so
5557                    // advance to find one.
5558                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5559                        diff_transforms.next();
5560                        continue;
5561                    }
5562                    let overshoot = excerpt_position - diff_transforms.start().0;
5563                    position += overshoot;
5564                }
5565            }
5566
5567            return position.0;
5568        }
5569    }
5570
5571    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5572    fn resolve_summary_for_min_or_max_anchor<MBD>(
5573        &self,
5574        anchor: &Anchor,
5575        excerpt_position: ExcerptDimension<MBD>,
5576        diff_transforms: &mut Cursor<
5577            DiffTransform,
5578            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5579        >,
5580    ) -> MBD
5581    where
5582        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5583    {
5584        loop {
5585            let transform_end_position = diff_transforms.end().0;
5586            let item = diff_transforms.item();
5587            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5588
5589            // A right-biased anchor at a transform boundary belongs to the
5590            // *next* transform, so advance past the current one.
5591            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5592                diff_transforms.next();
5593                continue;
5594            }
5595
5596            let mut position = diff_transforms.start().1;
5597            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5598                let overshoot = excerpt_position - diff_transforms.start().0;
5599                position += overshoot;
5600            }
5601
5602            return position.0;
5603        }
5604    }
5605
5606    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5607        let mut cursor = self
5608            .excerpts
5609            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5610        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5611
5612        cursor.seek(&Some(locator), Bias::Left);
5613        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5614            cursor.prev();
5615        }
5616
5617        let mut position = cursor.start().1;
5618        if let Some(excerpt) = cursor.item()
5619            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5620        {
5621            let excerpt_buffer_start = excerpt
5622                .buffer
5623                .offset_for_anchor(&excerpt.range.context.start);
5624            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5625            let buffer_position = cmp::min(
5626                excerpt_buffer_end,
5627                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5628            );
5629            if buffer_position > excerpt_buffer_start {
5630                position += buffer_position - excerpt_buffer_start;
5631            }
5632        }
5633        position
5634    }
5635
5636    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5637        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5638            excerpt_id = *replacement;
5639        }
5640        excerpt_id
5641    }
5642
5643    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5644    where
5645        MBD: MultiBufferDimension
5646            + Ord
5647            + Sub<Output = MBD::TextDimension>
5648            + AddAssign<MBD::TextDimension>,
5649        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5650        I: 'a + IntoIterator<Item = &'a Anchor>,
5651    {
5652        let mut anchors = anchors.into_iter().peekable();
5653        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5654        let mut diff_transforms_cursor = self
5655            .diff_transforms
5656            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5657        diff_transforms_cursor.next();
5658
5659        let mut summaries = Vec::new();
5660        while let Some(anchor) = anchors.peek() {
5661            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5662
5663            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5664                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5665            });
5666
5667            let locator = self.excerpt_locator_for_id(excerpt_id);
5668            cursor.seek_forward(locator, Bias::Left);
5669            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5670                cursor.prev();
5671            }
5672
5673            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5674            if let Some(excerpt) = cursor.item() {
5675                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5676                    let position = self.resolve_summary_for_min_or_max_anchor(
5677                        &Anchor::min(),
5678                        excerpt_start_position,
5679                        &mut diff_transforms_cursor,
5680                    );
5681                    summaries.extend(excerpt_anchors.map(|_| position));
5682                    continue;
5683                }
5684                let excerpt_buffer_start = excerpt
5685                    .range
5686                    .context
5687                    .start
5688                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5689                let excerpt_buffer_end = excerpt
5690                    .range
5691                    .context
5692                    .end
5693                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5694                for (buffer_summary, anchor) in excerpt
5695                    .buffer
5696                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5697                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5698                    )
5699                {
5700                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5701                    let mut position = excerpt_start_position;
5702                    if summary > excerpt_buffer_start {
5703                        position += summary - excerpt_buffer_start;
5704                    }
5705
5706                    if diff_transforms_cursor.start().0 < position {
5707                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5708                    }
5709
5710                    summaries.push(self.resolve_summary_for_anchor(
5711                        anchor,
5712                        position,
5713                        &mut diff_transforms_cursor,
5714                        &excerpt.buffer,
5715                    ));
5716                }
5717            } else {
5718                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5719                let position = self.resolve_summary_for_min_or_max_anchor(
5720                    &Anchor::max(),
5721                    excerpt_start_position,
5722                    &mut diff_transforms_cursor,
5723                );
5724                summaries.extend(excerpt_anchors.map(|_| position));
5725            }
5726        }
5727
5728        summaries
5729    }
5730
5731    pub fn dimensions_from_points<'a, MBD>(
5732        &'a self,
5733        points: impl 'a + IntoIterator<Item = Point>,
5734    ) -> impl 'a + Iterator<Item = MBD>
5735    where
5736        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5737    {
5738        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5739        cursor.seek(&DimensionPair {
5740            key: Point::default(),
5741            value: None,
5742        });
5743        let mut points = points.into_iter();
5744        iter::from_fn(move || {
5745            let point = points.next()?;
5746
5747            cursor.seek_forward(&DimensionPair {
5748                key: point,
5749                value: None,
5750            });
5751
5752            if let Some(region) = cursor.region() {
5753                let overshoot = point - region.range.start.key;
5754                let buffer_point = region.buffer_range.start + overshoot;
5755                let mut position = region.range.start.value.unwrap();
5756                position.add_text_dim(
5757                    &region
5758                        .buffer
5759                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5760                );
5761                if point == region.range.end.key && region.has_trailing_newline {
5762                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5763                }
5764                Some(position)
5765            } else {
5766                Some(MBD::from_summary(&self.text_summary()))
5767            }
5768        })
5769    }
5770
5771    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5772    where
5773        I: 'a + IntoIterator<Item = &'a Anchor>,
5774    {
5775        let mut anchors = anchors.into_iter().enumerate().peekable();
5776        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5777        cursor.next();
5778
5779        let mut result = Vec::new();
5780
5781        while let Some((_, anchor)) = anchors.peek() {
5782            let old_excerpt_id = anchor.excerpt_id;
5783
5784            // Find the location where this anchor's excerpt should be.
5785            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5786            cursor.seek_forward(&Some(old_locator), Bias::Left);
5787
5788            let next_excerpt = cursor.item();
5789            let prev_excerpt = cursor.prev_item();
5790
5791            // Process all of the anchors for this excerpt.
5792            while let Some((anchor_ix, &anchor)) =
5793                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5794            {
5795                let mut anchor = anchor;
5796
5797                // Leave min and max anchors unchanged if invalid or
5798                // if the old excerpt still exists at this location
5799                let mut kept_position = next_excerpt
5800                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5801                    || old_excerpt_id == ExcerptId::max()
5802                    || old_excerpt_id == ExcerptId::min();
5803
5804                // If the old excerpt no longer exists at this location, then attempt to
5805                // find an equivalent position for this anchor in an adjacent excerpt.
5806                if !kept_position {
5807                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5808                        if excerpt.contains(&anchor) {
5809                            anchor.excerpt_id = excerpt.id;
5810                            kept_position = true;
5811                            break;
5812                        }
5813                    }
5814                }
5815
5816                // If there's no adjacent excerpt that contains the anchor's position,
5817                // then report that the anchor has lost its position.
5818                if !kept_position {
5819                    anchor = if let Some(excerpt) = next_excerpt {
5820                        let mut text_anchor = excerpt
5821                            .range
5822                            .context
5823                            .start
5824                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5825                        if text_anchor
5826                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5827                            .is_gt()
5828                        {
5829                            text_anchor = excerpt.range.context.end;
5830                        }
5831                        Anchor::in_buffer(excerpt.id, text_anchor)
5832                    } else if let Some(excerpt) = prev_excerpt {
5833                        let mut text_anchor = excerpt
5834                            .range
5835                            .context
5836                            .end
5837                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5838                        if text_anchor
5839                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5840                            .is_lt()
5841                        {
5842                            text_anchor = excerpt.range.context.start;
5843                        }
5844                        Anchor::in_buffer(excerpt.id, text_anchor)
5845                    } else if anchor.text_anchor.bias == Bias::Left {
5846                        Anchor::min()
5847                    } else {
5848                        Anchor::max()
5849                    };
5850                }
5851
5852                result.push((anchor_ix, anchor, kept_position));
5853            }
5854        }
5855        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5856        result
5857    }
5858
5859    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5860        self.anchor_at(position, Bias::Left)
5861    }
5862
5863    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5864        self.anchor_at(position, Bias::Right)
5865    }
5866
5867    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5868        let offset = position.to_offset(self);
5869
5870        // Find the given position in the diff transforms. Determine the corresponding
5871        // offset in the excerpts, and whether the position is within a deleted hunk.
5872        let mut diff_transforms = self
5873            .diff_transforms
5874            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5875        diff_transforms.seek(&offset, Bias::Right);
5876
5877        if offset == diff_transforms.start().0
5878            && bias == Bias::Left
5879            && let Some(prev_item) = diff_transforms.prev_item()
5880            && let DiffTransform::DeletedHunk { .. } = prev_item
5881        {
5882            diff_transforms.prev();
5883        }
5884        let offset_in_transform = offset - diff_transforms.start().0;
5885        let mut excerpt_offset = diff_transforms.start().1;
5886        let mut diff_base_anchor = None;
5887        if let Some(DiffTransform::DeletedHunk {
5888            buffer_id,
5889            base_text_byte_range,
5890            has_trailing_newline,
5891            ..
5892        }) = diff_transforms.item()
5893        {
5894            let diff = self.diffs.get(buffer_id).expect("missing diff");
5895            if offset_in_transform > base_text_byte_range.len() {
5896                debug_assert!(*has_trailing_newline);
5897                bias = Bias::Right;
5898            } else {
5899                diff_base_anchor = Some(
5900                    diff.base_text()
5901                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5902                );
5903                bias = Bias::Left;
5904            }
5905        } else {
5906            excerpt_offset += MultiBufferOffset(offset_in_transform);
5907        };
5908
5909        let mut excerpts = self
5910            .excerpts
5911            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5912        excerpts.seek(&excerpt_offset, Bias::Right);
5913        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5914            excerpts.prev();
5915        }
5916        if let Some(excerpt) = excerpts.item() {
5917            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5918            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5919                overshoot -= 1;
5920                bias = Bias::Right;
5921            }
5922
5923            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5924            let text_anchor =
5925                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5926            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5927            match diff_base_anchor {
5928                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5929                None => anchor,
5930            }
5931        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5932        {
5933            Anchor::min()
5934        } else {
5935            Anchor::max()
5936        }
5937    }
5938
5939    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5940    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5941        let (excerpt, buffer, _) = self.as_singleton()?;
5942        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5943            Some(Anchor::in_buffer(excerpt, text_anchor))
5944        } else {
5945            None
5946        }
5947    }
5948
5949    /// Returns an anchor for the given excerpt and text anchor,
5950    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5951    pub fn anchor_range_in_excerpt(
5952        &self,
5953        excerpt_id: ExcerptId,
5954        text_anchor: Range<text::Anchor>,
5955    ) -> Option<Range<Anchor>> {
5956        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5957
5958        Some(
5959            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5960                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5961        )
5962    }
5963
5964    /// Returns an anchor for the given excerpt and text anchor,
5965    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5966    pub fn anchor_in_excerpt(
5967        &self,
5968        excerpt_id: ExcerptId,
5969        text_anchor: text::Anchor,
5970    ) -> Option<Anchor> {
5971        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5972        Self::anchor_in_excerpt_(excerpt, text_anchor)
5973    }
5974
5975    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5976    pub fn anchors_in_excerpt(
5977        &self,
5978        excerpt_id: ExcerptId,
5979        text_anchors: impl IntoIterator<Item = text::Anchor>,
5980    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5981        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5982        Some(
5983            text_anchors
5984                .into_iter()
5985                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5986        )
5987    }
5988
5989    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5990        match text_anchor.buffer_id {
5991            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5992            Some(_) => return None,
5993            None if text_anchor.is_max() || text_anchor.is_min() => {
5994                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5995            }
5996            None => return None,
5997        }
5998
5999        let context = &excerpt.range.context;
6000        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
6001            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
6002        {
6003            return None;
6004        }
6005
6006        Some(Anchor::in_buffer(excerpt.id, text_anchor))
6007    }
6008
6009    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6010        Some(self.excerpt(excerpt_id)?.range.context.clone())
6011    }
6012
6013    pub fn excerpt_range_for_excerpt(
6014        &self,
6015        excerpt_id: ExcerptId,
6016    ) -> Option<ExcerptRange<text::Anchor>> {
6017        Some(self.excerpt(excerpt_id)?.range.clone())
6018    }
6019
6020    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
6021        if anchor.is_min() || anchor.is_max() {
6022            // todo(lw): should be `!self.is_empty()`
6023            true
6024        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
6025            excerpt.buffer.can_resolve(&anchor.text_anchor)
6026        } else {
6027            false
6028        }
6029    }
6030
6031    pub fn excerpts(
6032        &self,
6033    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
6034        self.excerpts
6035            .iter()
6036            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
6037    }
6038
6039    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
6040    where
6041        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6042        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6043    {
6044        let excerpts = self.excerpts.cursor(());
6045        let diff_transforms = self.diff_transforms.cursor(());
6046        MultiBufferCursor {
6047            excerpts,
6048            diff_transforms,
6049            diffs: &self.diffs,
6050            cached_region: OnceCell::new(),
6051        }
6052    }
6053
6054    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6055        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6056        let mut excerpts = self
6057            .excerpts
6058            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6059        excerpts.seek(&Some(start_locator), Bias::Left);
6060        excerpts.prev();
6061
6062        let mut diff_transforms = self
6063            .diff_transforms
6064            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6065        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6066        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6067            diff_transforms.next();
6068        }
6069
6070        let excerpt = excerpts.item()?;
6071        Some(MultiBufferExcerpt {
6072            excerpt,
6073            offset: diff_transforms.start().output_dimension.0,
6074            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6075            excerpt_offset: excerpts.start().1,
6076            diff_transforms,
6077        })
6078    }
6079
6080    pub fn excerpt_boundaries_in_range<R, T>(
6081        &self,
6082        range: R,
6083    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6084    where
6085        R: RangeBounds<T>,
6086        T: ToOffset,
6087    {
6088        let start_offset;
6089        let start = match range.start_bound() {
6090            Bound::Included(start) => {
6091                start_offset = start.to_offset(self);
6092                Bound::Included(start_offset)
6093            }
6094            Bound::Excluded(_) => {
6095                panic!("not supported")
6096            }
6097            Bound::Unbounded => {
6098                start_offset = MultiBufferOffset::ZERO;
6099                Bound::Unbounded
6100            }
6101        };
6102        let end = match range.end_bound() {
6103            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6104            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6105            Bound::Unbounded => Bound::Unbounded,
6106        };
6107        let bounds = (start, end);
6108        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6109        cursor.seek(&DimensionPair {
6110            key: start_offset,
6111            value: None,
6112        });
6113
6114        if cursor
6115            .fetch_excerpt_with_range()
6116            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6117        {
6118            cursor.prev_excerpt();
6119        } else {
6120            cursor.seek_to_start_of_current_excerpt();
6121        }
6122        let mut prev_region = cursor
6123            .fetch_excerpt_with_range()
6124            .map(|(excerpt, _)| excerpt);
6125
6126        cursor.next_excerpt_forwards();
6127
6128        iter::from_fn(move || {
6129            loop {
6130                if self.singleton {
6131                    return None;
6132                }
6133
6134                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6135                cursor.next_excerpt_forwards();
6136                if !bounds.contains(&next_range.start.key) {
6137                    prev_region = Some(next_excerpt);
6138                    continue;
6139                }
6140
6141                let next_region_start = next_range.start.value.unwrap();
6142                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6143                    range.start.value.unwrap()
6144                } else {
6145                    self.max_point()
6146                };
6147
6148                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6149                    id: region.id,
6150                    buffer: region.buffer.clone(),
6151                    buffer_id: region.buffer_id,
6152                    range: region.range.clone(),
6153                    end_row: MultiBufferRow(next_region_start.row),
6154                });
6155
6156                let next = ExcerptInfo {
6157                    id: next_excerpt.id,
6158                    buffer: next_excerpt.buffer.clone(),
6159                    buffer_id: next_excerpt.buffer_id,
6160                    range: next_excerpt.range.clone(),
6161                    end_row: if next_excerpt.has_trailing_newline {
6162                        MultiBufferRow(next_region_end.row - 1)
6163                    } else {
6164                        MultiBufferRow(next_region_end.row)
6165                    },
6166                };
6167
6168                let row = MultiBufferRow(next_region_start.row);
6169
6170                prev_region = Some(next_excerpt);
6171
6172                return Some(ExcerptBoundary { row, prev, next });
6173            }
6174        })
6175    }
6176
6177    pub fn edit_count(&self) -> usize {
6178        self.edit_count
6179    }
6180
6181    pub fn non_text_state_update_count(&self) -> usize {
6182        self.non_text_state_update_count
6183    }
6184
6185    /// Returns the smallest enclosing bracket ranges containing the given range or
6186    /// None if no brackets contain range or the range is not contained in a single
6187    /// excerpt
6188    ///
6189    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6190    #[ztracing::instrument(skip_all)]
6191    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6192        &self,
6193        range: Range<T>,
6194        range_filter: Option<
6195            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6196        >,
6197    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6198        let range = range.start.to_offset(self)..range.end.to_offset(self);
6199        let mut excerpt = self.excerpt_containing(range.clone())?;
6200        let buffer = excerpt.buffer();
6201        let excerpt_buffer_range = excerpt.buffer_range();
6202
6203        // Filter to ranges contained in the excerpt
6204        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6205            excerpt_buffer_range.contains(&BufferOffset(open.start))
6206                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6207                && range_filter.is_none_or(|filter| {
6208                    filter(
6209                        buffer,
6210                        BufferOffset(open.start)..BufferOffset(close.end),
6211                        BufferOffset(close.start)..BufferOffset(close.end),
6212                    )
6213                })
6214        };
6215
6216        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6217            excerpt.map_range_to_buffer(range),
6218            Some(&range_filter),
6219        )?;
6220
6221        Some((
6222            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6223            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6224        ))
6225    }
6226
6227    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6228    /// not contained in a single excerpt
6229    pub fn enclosing_bracket_ranges<T: ToOffset>(
6230        &self,
6231        range: Range<T>,
6232    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6233    {
6234        let range = range.start.to_offset(self)..range.end.to_offset(self);
6235        let mut excerpt = self.excerpt_containing(range.clone())?;
6236
6237        Some(
6238            excerpt
6239                .buffer()
6240                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6241                .filter_map(move |pair| {
6242                    let open_range =
6243                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6244                    let close_range =
6245                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6246                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6247                        Some((
6248                            excerpt.map_range_from_buffer(open_range),
6249                            excerpt.map_range_from_buffer(close_range),
6250                        ))
6251                    } else {
6252                        None
6253                    }
6254                }),
6255        )
6256    }
6257
6258    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6259    /// not contained in a single excerpt
6260    pub fn text_object_ranges<T: ToOffset>(
6261        &self,
6262        range: Range<T>,
6263        options: TreeSitterOptions,
6264    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6265        let range = range.start.to_offset(self)..range.end.to_offset(self);
6266        self.excerpt_containing(range.clone())
6267            .map(|mut excerpt| {
6268                excerpt
6269                    .buffer()
6270                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6271                    .filter_map(move |(range, text_object)| {
6272                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6273                        if excerpt.contains_buffer_range(range.clone()) {
6274                            Some((excerpt.map_range_from_buffer(range), text_object))
6275                        } else {
6276                            None
6277                        }
6278                    })
6279            })
6280            .into_iter()
6281            .flatten()
6282    }
6283
6284    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6285    /// not contained in a single excerpt
6286    pub fn bracket_ranges<T: ToOffset>(
6287        &self,
6288        range: Range<T>,
6289    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6290    {
6291        let range = range.start.to_offset(self)..range.end.to_offset(self);
6292        let mut excerpt = self.excerpt_containing(range.clone())?;
6293        Some(
6294            excerpt
6295                .buffer()
6296                .bracket_ranges(excerpt.map_range_to_buffer(range))
6297                .filter_map(move |pair| {
6298                    let open_range =
6299                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6300                    let close_range =
6301                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6302                    excerpt
6303                        .contains_buffer_range(open_range.start..close_range.end)
6304                        .then(|| BracketMatch {
6305                            open_range: excerpt.map_range_from_buffer(open_range),
6306                            close_range: excerpt.map_range_from_buffer(close_range),
6307                            color_index: pair.color_index,
6308                            newline_only: pair.newline_only,
6309                            syntax_layer_depth: pair.syntax_layer_depth,
6310                        })
6311                })
6312                .map(BracketMatch::bracket_ranges),
6313        )
6314    }
6315
6316    pub fn redacted_ranges<'a, T: ToOffset>(
6317        &'a self,
6318        range: Range<T>,
6319        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6320    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6321        let range = range.start.to_offset(self)..range.end.to_offset(self);
6322        self.lift_buffer_metadata(range, move |buffer, range| {
6323            if redaction_enabled(buffer.file()) {
6324                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6325            } else {
6326                None
6327            }
6328        })
6329        .map(|(range, _, _)| range)
6330    }
6331
6332    pub fn runnable_ranges(
6333        &self,
6334        range: Range<Anchor>,
6335    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6336        let range = range.start.to_offset(self)..range.end.to_offset(self);
6337        self.lift_buffer_metadata(range, move |buffer, range| {
6338            Some(
6339                buffer
6340                    .runnable_ranges(range.clone())
6341                    .filter(move |runnable| {
6342                        runnable.run_range.start >= range.start
6343                            && runnable.run_range.end < range.end
6344                    })
6345                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6346            )
6347        })
6348        .map(|(run_range, runnable, _)| (run_range, runnable))
6349    }
6350
6351    pub fn line_indents(
6352        &self,
6353        start_row: MultiBufferRow,
6354        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6355    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6356        let max_point = self.max_point();
6357        let mut cursor = self.cursor::<Point, Point>();
6358        cursor.seek(&Point::new(start_row.0, 0));
6359        iter::from_fn(move || {
6360            let mut region = cursor.region()?;
6361            while !buffer_filter(&region.excerpt.buffer) {
6362                cursor.next();
6363                region = cursor.region()?;
6364            }
6365            let region = cursor.region()?;
6366            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6367            let buffer_start_row =
6368                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6369
6370            let buffer_end_row = if region.is_main_buffer
6371                && (region.has_trailing_newline || region.range.end == max_point)
6372            {
6373                region.buffer_range.end.row
6374            } else {
6375                region.buffer_range.end.row.saturating_sub(1)
6376            };
6377
6378            let line_indents = region
6379                .buffer
6380                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6381            let region_buffer_row = region.buffer_range.start.row;
6382            let region_row = region.range.start.row;
6383            let region_buffer = &region.excerpt.buffer;
6384            cursor.next();
6385            Some(line_indents.map(move |(buffer_row, indent)| {
6386                let row = region_row + (buffer_row - region_buffer_row);
6387                (MultiBufferRow(row), indent, region_buffer.as_ref())
6388            }))
6389        })
6390        .flatten()
6391    }
6392
6393    pub fn reversed_line_indents(
6394        &self,
6395        end_row: MultiBufferRow,
6396        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6397    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6398        let max_point = self.max_point();
6399        let mut cursor = self.cursor::<Point, Point>();
6400        cursor.seek(&Point::new(end_row.0, 0));
6401        iter::from_fn(move || {
6402            let mut region = cursor.region()?;
6403            while !buffer_filter(&region.excerpt.buffer) {
6404                cursor.prev();
6405                region = cursor.region()?;
6406            }
6407            let region = cursor.region()?;
6408
6409            let buffer_start_row = region.buffer_range.start.row;
6410            let buffer_end_row = if region.is_main_buffer
6411                && (region.has_trailing_newline || region.range.end == max_point)
6412            {
6413                region.buffer_range.end.row + 1
6414            } else {
6415                region.buffer_range.end.row
6416            };
6417
6418            let overshoot = end_row.0 - region.range.start.row;
6419            let buffer_end_row =
6420                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6421
6422            let line_indents = region
6423                .buffer
6424                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6425            let region_buffer_row = region.buffer_range.start.row;
6426            let region_row = region.range.start.row;
6427            let region_buffer = &region.excerpt.buffer;
6428            cursor.prev();
6429            Some(line_indents.map(move |(buffer_row, indent)| {
6430                let row = region_row + (buffer_row - region_buffer_row);
6431                (MultiBufferRow(row), indent, region_buffer.as_ref())
6432            }))
6433        })
6434        .flatten()
6435    }
6436
6437    pub async fn enclosing_indent(
6438        &self,
6439        mut target_row: MultiBufferRow,
6440    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6441        let max_row = MultiBufferRow(self.max_point().row);
6442        if target_row >= max_row {
6443            return None;
6444        }
6445
6446        let mut target_indent = self.line_indent_for_row(target_row);
6447
6448        // If the current row is at the start of an indented block, we want to return this
6449        // block as the enclosing indent.
6450        if !target_indent.is_line_empty() && target_row < max_row {
6451            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6452            if !next_line_indent.is_line_empty()
6453                && target_indent.raw_len() < next_line_indent.raw_len()
6454            {
6455                target_indent = next_line_indent;
6456                target_row.0 += 1;
6457            }
6458        }
6459
6460        const SEARCH_ROW_LIMIT: u32 = 25000;
6461        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6462        const YIELD_INTERVAL: u32 = 100;
6463
6464        let mut accessed_row_counter = 0;
6465
6466        // If there is a blank line at the current row, search for the next non indented lines
6467        if target_indent.is_line_empty() {
6468            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6469            let end =
6470                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6471
6472            let mut non_empty_line_above = None;
6473            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6474                if row < start {
6475                    break;
6476                }
6477                accessed_row_counter += 1;
6478                if accessed_row_counter == YIELD_INTERVAL {
6479                    accessed_row_counter = 0;
6480                    yield_now().await;
6481                }
6482                if !indent.is_line_empty() {
6483                    non_empty_line_above = Some((row, indent));
6484                    break;
6485                }
6486            }
6487
6488            let mut non_empty_line_below = None;
6489            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6490                if row > end {
6491                    break;
6492                }
6493                accessed_row_counter += 1;
6494                if accessed_row_counter == YIELD_INTERVAL {
6495                    accessed_row_counter = 0;
6496                    yield_now().await;
6497                }
6498                if !indent.is_line_empty() {
6499                    non_empty_line_below = Some((row, indent));
6500                    break;
6501                }
6502            }
6503
6504            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6505                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6506                    if above_indent.raw_len() >= below_indent.raw_len() {
6507                        (above_row, above_indent)
6508                    } else {
6509                        (below_row, below_indent)
6510                    }
6511                }
6512                (Some(above), None) => above,
6513                (None, Some(below)) => below,
6514                _ => return None,
6515            };
6516
6517            target_indent = indent;
6518            target_row = row;
6519        }
6520
6521        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6522        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6523
6524        let mut start_indent = None;
6525        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6526            if row < start {
6527                break;
6528            }
6529            accessed_row_counter += 1;
6530            if accessed_row_counter == YIELD_INTERVAL {
6531                accessed_row_counter = 0;
6532                yield_now().await;
6533            }
6534            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6535                start_indent = Some((row, indent));
6536                break;
6537            }
6538        }
6539        let (start_row, start_indent_size) = start_indent?;
6540
6541        let mut end_indent = (end, None);
6542        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6543            if row > end {
6544                break;
6545            }
6546            accessed_row_counter += 1;
6547            if accessed_row_counter == YIELD_INTERVAL {
6548                accessed_row_counter = 0;
6549                yield_now().await;
6550            }
6551            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6552                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6553                break;
6554            }
6555        }
6556        let (end_row, end_indent_size) = end_indent;
6557
6558        let indent = if let Some(end_indent_size) = end_indent_size {
6559            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6560                start_indent_size
6561            } else {
6562                end_indent_size
6563            }
6564        } else {
6565            start_indent_size
6566        };
6567
6568        Some((start_row..end_row, indent))
6569    }
6570
6571    pub fn indent_guides_in_range<T: ToPoint>(
6572        &self,
6573        range: Range<T>,
6574        ignore_disabled_for_language: bool,
6575        cx: &App,
6576    ) -> impl Iterator<Item = IndentGuide> {
6577        let range = range.start.to_point(self)..range.end.to_point(self);
6578        let start_row = MultiBufferRow(range.start.row);
6579        let end_row = MultiBufferRow(range.end.row);
6580
6581        let mut row_indents = self.line_indents(start_row, |buffer| {
6582            let settings =
6583                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6584            settings.indent_guides.enabled || ignore_disabled_for_language
6585        });
6586
6587        let mut result = Vec::new();
6588        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6589
6590        let mut prev_settings = None;
6591        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6592            if first_row > end_row {
6593                break;
6594            }
6595            let current_depth = indent_stack.len() as u32;
6596
6597            // Avoid retrieving the language settings repeatedly for every buffer row.
6598            if let Some((prev_buffer_id, _)) = &prev_settings
6599                && prev_buffer_id != &buffer.remote_id()
6600            {
6601                prev_settings.take();
6602            }
6603            let settings = &prev_settings
6604                .get_or_insert_with(|| {
6605                    (
6606                        buffer.remote_id(),
6607                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6608                    )
6609                })
6610                .1;
6611            let tab_size = settings.tab_size.get();
6612
6613            // When encountering empty, continue until found useful line indent
6614            // then add to the indent stack with the depth found
6615            let mut found_indent = false;
6616            let mut last_row = first_row;
6617            if line_indent.is_line_blank() {
6618                while !found_indent {
6619                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6620                        break;
6621                    };
6622                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6623                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6624                        break;
6625                    }
6626
6627                    if new_line_indent.is_line_blank() {
6628                        continue;
6629                    }
6630                    last_row = target_row.min(end_row);
6631                    line_indent = new_line_indent;
6632                    found_indent = true;
6633                    break;
6634                }
6635            } else {
6636                found_indent = true
6637            }
6638
6639            let depth = if found_indent {
6640                line_indent.len(tab_size) / tab_size
6641            } else {
6642                0
6643            };
6644
6645            match depth.cmp(&current_depth) {
6646                cmp::Ordering::Less => {
6647                    for _ in 0..(current_depth - depth) {
6648                        let mut indent = indent_stack.pop().unwrap();
6649                        if last_row != first_row {
6650                            // In this case, we landed on an empty row, had to seek forward,
6651                            // and discovered that the indent we where on is ending.
6652                            // This means that the last display row must
6653                            // be on line that ends this indent range, so we
6654                            // should display the range up to the first non-empty line
6655                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6656                        }
6657
6658                        result.push(indent)
6659                    }
6660                }
6661                cmp::Ordering::Greater => {
6662                    for next_depth in current_depth..depth {
6663                        indent_stack.push(IndentGuide {
6664                            buffer_id: buffer.remote_id(),
6665                            start_row: first_row,
6666                            end_row: last_row,
6667                            depth: next_depth,
6668                            tab_size,
6669                            settings: settings.indent_guides.clone(),
6670                        });
6671                    }
6672                }
6673                _ => {}
6674            }
6675
6676            for indent in indent_stack.iter_mut() {
6677                indent.end_row = last_row;
6678            }
6679        }
6680
6681        result.extend(indent_stack);
6682        result.into_iter()
6683    }
6684
6685    pub fn trailing_excerpt_update_count(&self) -> usize {
6686        self.trailing_excerpt_update_count
6687    }
6688
6689    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6690        self.point_to_buffer_offset(point)
6691            .and_then(|(buffer, _)| buffer.file())
6692    }
6693
6694    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6695        self.point_to_buffer_offset(offset)
6696            .and_then(|(buffer, offset)| buffer.language_at(offset))
6697    }
6698
6699    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6700        self.excerpts
6701            .first()
6702            .map(|excerpt| &excerpt.buffer)
6703            .map(|buffer| {
6704                language_settings(
6705                    buffer.language().map(|language| language.name()),
6706                    buffer.file(),
6707                    cx,
6708                )
6709            })
6710            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6711    }
6712
6713    pub fn language_settings_at<'a, T: ToOffset>(
6714        &'a self,
6715        point: T,
6716        cx: &'a App,
6717    ) -> Cow<'a, LanguageSettings> {
6718        let mut language = None;
6719        let mut file = None;
6720        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6721            language = buffer.language_at(offset);
6722            file = buffer.file();
6723        }
6724        language_settings(language.map(|l| l.name()), file, cx)
6725    }
6726
6727    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6728        self.point_to_buffer_offset(point)
6729            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6730    }
6731
6732    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6733        self.point_to_buffer_offset(point)
6734            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6735            .unwrap_or_default()
6736    }
6737
6738    pub fn language_indent_size_at<T: ToOffset>(
6739        &self,
6740        position: T,
6741        cx: &App,
6742    ) -> Option<IndentSize> {
6743        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6744        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6745    }
6746
6747    pub fn is_dirty(&self) -> bool {
6748        self.is_dirty
6749    }
6750
6751    pub fn has_deleted_file(&self) -> bool {
6752        self.has_deleted_file
6753    }
6754
6755    pub fn has_conflict(&self) -> bool {
6756        self.has_conflict
6757    }
6758
6759    pub fn has_diagnostics(&self) -> bool {
6760        self.excerpts
6761            .iter()
6762            .any(|excerpt| excerpt.buffer.has_diagnostics())
6763    }
6764
6765    pub fn diagnostic_group(
6766        &self,
6767        buffer_id: BufferId,
6768        group_id: usize,
6769    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6770        self.lift_buffer_metadata::<Point, _, _>(
6771            Point::zero()..self.max_point(),
6772            move |buffer, range| {
6773                if buffer.remote_id() != buffer_id {
6774                    return None;
6775                };
6776                Some(
6777                    buffer
6778                        .diagnostics_in_range(range, false)
6779                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6780                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6781                )
6782            },
6783        )
6784        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6785    }
6786
6787    pub fn diagnostics_in_range<'a, MBD>(
6788        &'a self,
6789        range: Range<MBD>,
6790    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6791    where
6792        MBD::TextDimension: 'a
6793            + text::ToOffset
6794            + text::FromAnchor
6795            + Sub<Output = MBD::TextDimension>
6796            + fmt::Debug
6797            + ops::Add<Output = MBD::TextDimension>
6798            + ops::AddAssign
6799            + Ord,
6800        MBD: MultiBufferDimension
6801            + Ord
6802            + Sub<Output = MBD::TextDimension>
6803            + ops::Add<MBD::TextDimension, Output = MBD>
6804            + ops::AddAssign<MBD::TextDimension>
6805            + 'a,
6806    {
6807        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6808            Some(
6809                buffer
6810                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6811                    .map(|entry| (entry.range, entry.diagnostic)),
6812            )
6813        })
6814        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6815    }
6816
6817    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6818        &'a self,
6819        range: Range<MBD>,
6820    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6821    where
6822        MBD: MultiBufferDimension
6823            + Ord
6824            + Sub<Output = MBD::TextDimension>
6825            + ops::Add<MBD::TextDimension, Output = MBD>
6826            + ops::AddAssign<MBD::TextDimension>,
6827        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6828            + ops::Add<Output = MBD::TextDimension>
6829            + text::ToOffset
6830            + text::FromAnchor
6831            + AddAssign<MBD::TextDimension>
6832            + Ord,
6833    {
6834        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6835            Some(
6836                buffer
6837                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6838                    .map(|entry| (entry.range, entry.diagnostic)),
6839            )
6840        })
6841        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6842    }
6843
6844    pub fn syntax_ancestor<T: ToOffset>(
6845        &self,
6846        range: Range<T>,
6847    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6848        let range = range.start.to_offset(self)..range.end.to_offset(self);
6849        let mut excerpt = self.excerpt_containing(range.clone())?;
6850        let node = excerpt
6851            .buffer()
6852            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6853        let node_range = node.byte_range();
6854        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6855        if !excerpt.contains_buffer_range(node_range.clone()) {
6856            return None;
6857        };
6858        Some((node, excerpt.map_range_from_buffer(node_range)))
6859    }
6860
6861    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6862        let (excerpt_id, _, buffer) = self.as_singleton()?;
6863        let outline = buffer.outline(theme);
6864        Some(Outline::new(
6865            outline
6866                .items
6867                .into_iter()
6868                .flat_map(|item| {
6869                    Some(OutlineItem {
6870                        depth: item.depth,
6871                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6872                        source_range_for_text: self
6873                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6874                        text: item.text,
6875                        highlight_ranges: item.highlight_ranges,
6876                        name_ranges: item.name_ranges,
6877                        body_range: item.body_range.and_then(|body_range| {
6878                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6879                        }),
6880                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6881                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6882                        }),
6883                    })
6884                })
6885                .collect(),
6886        ))
6887    }
6888
6889    pub fn symbols_containing<T: ToOffset>(
6890        &self,
6891        offset: T,
6892        theme: Option<&SyntaxTheme>,
6893    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6894        let anchor = self.anchor_before(offset);
6895        let excerpt @ &Excerpt {
6896            id: excerpt_id,
6897            buffer_id,
6898            ref buffer,
6899            ..
6900        } = self.excerpt(anchor.excerpt_id)?;
6901        if cfg!(debug_assertions) {
6902            match anchor.text_anchor.buffer_id {
6903                // we clearly are hitting this according to sentry, but in what situations can this occur?
6904                Some(anchor_buffer_id) => {
6905                    assert_eq!(
6906                        anchor_buffer_id, buffer_id,
6907                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6908                    )
6909                }
6910                None => assert!(anchor.is_max()),
6911            }
6912        };
6913        Some((
6914            buffer_id,
6915            buffer
6916                .symbols_containing(anchor.text_anchor, theme)
6917                .into_iter()
6918                .flat_map(|item| {
6919                    Some(OutlineItem {
6920                        depth: item.depth,
6921                        source_range_for_text: Anchor::range_in_buffer(
6922                            excerpt_id,
6923                            item.source_range_for_text,
6924                        ),
6925                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6926                        text: item.text,
6927                        highlight_ranges: item.highlight_ranges,
6928                        name_ranges: item.name_ranges,
6929                        body_range: item
6930                            .body_range
6931                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6932                        annotation_range: item
6933                            .annotation_range
6934                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6935                    })
6936                })
6937                .collect(),
6938        ))
6939    }
6940
6941    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6942        self.try_excerpt_locator_for_id(id)
6943            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6944    }
6945
6946    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6947        if id == ExcerptId::min() {
6948            Some(Locator::min_ref())
6949        } else if id == ExcerptId::max() {
6950            Some(Locator::max_ref())
6951        } else {
6952            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6953            if let Some(entry) = item
6954                && entry.id == id
6955            {
6956                return Some(&entry.locator);
6957            }
6958            None
6959        }
6960    }
6961
6962    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6963    fn excerpt_locators_for_ids(
6964        &self,
6965        ids: impl IntoIterator<Item = ExcerptId>,
6966    ) -> SmallVec<[Locator; 1]> {
6967        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6968        sorted_ids.sort_unstable();
6969        sorted_ids.dedup();
6970        let mut locators = SmallVec::new();
6971
6972        while sorted_ids.last() == Some(&ExcerptId::max()) {
6973            sorted_ids.pop();
6974            locators.push(Locator::max());
6975        }
6976
6977        let mut sorted_ids = sorted_ids.into_iter().peekable();
6978        locators.extend(
6979            sorted_ids
6980                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6981                .map(|_| Locator::min()),
6982        );
6983
6984        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6985        for id in sorted_ids {
6986            if cursor.seek_forward(&id, Bias::Left) {
6987                locators.push(cursor.item().unwrap().locator.clone());
6988            } else {
6989                panic!("invalid excerpt id {:?}", id);
6990            }
6991        }
6992
6993        locators.sort_unstable();
6994        locators
6995    }
6996
6997    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6998        Some(self.excerpt(excerpt_id)?.buffer_id)
6999    }
7000
7001    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
7002        Some(&self.excerpt(excerpt_id)?.buffer)
7003    }
7004
7005    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
7006        let mut cursor = self
7007            .excerpts
7008            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
7009        let locator = self.excerpt_locator_for_id(excerpt_id);
7010        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
7011        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7012            sought_exact = true;
7013            cursor.prev();
7014        } else if excerpt_id == ExcerptId::min() {
7015            sought_exact = true;
7016        }
7017        if sought_exact {
7018            let start = cursor.start().1;
7019            let end = cursor.end().1;
7020            let mut diff_transforms = self
7021                .diff_transforms
7022                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
7023            diff_transforms.seek(&start, Bias::Left);
7024            let overshoot = start - diff_transforms.start().0;
7025            let start = diff_transforms.start().1 + overshoot;
7026            diff_transforms.seek(&end, Bias::Right);
7027            let overshoot = end - diff_transforms.start().0;
7028            let end = diff_transforms.start().1 + overshoot;
7029            Some(start.0..end.0)
7030        } else {
7031            None
7032        }
7033    }
7034
7035    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
7036    /// to have the latest excerpt id for the one passed in and will also remap
7037    /// `ExcerptId::max()` to the corresponding excertp ID.
7038    ///
7039    /// Callers of this function should generally use the resulting excerpt's `id` field
7040    /// afterwards.
7041    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
7042        let excerpt_id = self.latest_excerpt_id(excerpt_id);
7043        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
7044        let (_, _, item) =
7045            self.excerpts
7046                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
7047        if let Some(excerpt) = item
7048            && excerpt.id == excerpt_id
7049        {
7050            return Some(excerpt);
7051        } else if item.is_none() && excerpt_id == ExcerptId::max() {
7052            return self.excerpts.last();
7053        }
7054        None
7055    }
7056
7057    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7058    pub fn excerpt_containing<T: ToOffset>(
7059        &self,
7060        range: Range<T>,
7061    ) -> Option<MultiBufferExcerpt<'_>> {
7062        let range = range.start.to_offset(self)..range.end.to_offset(self);
7063        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7064        cursor.seek(&range.start);
7065
7066        let start_excerpt = cursor.excerpt()?;
7067        if range.end != range.start {
7068            cursor.seek_forward(&range.end);
7069            if cursor.excerpt()?.id != start_excerpt.id {
7070                return None;
7071            }
7072        }
7073
7074        cursor.seek_to_start_of_current_excerpt();
7075        let region = cursor.region()?;
7076        let offset = region.range.start;
7077        let buffer_offset = start_excerpt.buffer_start_offset();
7078        let excerpt_offset = *cursor.excerpts.start();
7079        Some(MultiBufferExcerpt {
7080            diff_transforms: cursor.diff_transforms,
7081            excerpt: start_excerpt,
7082            offset,
7083            buffer_offset,
7084            excerpt_offset,
7085        })
7086    }
7087
7088    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7089        if let Some(id) = anchor.text_anchor.buffer_id {
7090            return Some(id);
7091        }
7092        let excerpt = self.excerpt_containing(anchor..anchor)?;
7093        Some(excerpt.buffer_id())
7094    }
7095
7096    pub fn selections_in_range<'a>(
7097        &'a self,
7098        range: &'a Range<Anchor>,
7099        include_local: bool,
7100    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7101        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7102        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7103        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7104        cursor.seek(start_locator, Bias::Left);
7105        cursor
7106            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7107            .flat_map(move |excerpt| {
7108                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7109                if excerpt.id == range.start.excerpt_id {
7110                    query_range.start = range.start.text_anchor;
7111                }
7112                if excerpt.id == range.end.excerpt_id {
7113                    query_range.end = range.end.text_anchor;
7114                }
7115
7116                excerpt
7117                    .buffer
7118                    .selections_in_range(query_range, include_local)
7119                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7120                        selections.map(move |selection| {
7121                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7122                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7123                            if range.start.cmp(&start, self).is_gt() {
7124                                start = range.start;
7125                            }
7126                            if range.end.cmp(&end, self).is_lt() {
7127                                end = range.end;
7128                            }
7129
7130                            (
7131                                replica_id,
7132                                line_mode,
7133                                cursor_shape,
7134                                Selection {
7135                                    id: selection.id,
7136                                    start,
7137                                    end,
7138                                    reversed: selection.reversed,
7139                                    goal: selection.goal,
7140                                },
7141                            )
7142                        })
7143                    })
7144            })
7145    }
7146
7147    pub fn show_headers(&self) -> bool {
7148        self.show_headers
7149    }
7150
7151    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7152        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7153    }
7154
7155    pub fn all_diff_hunks_expanded(&self) -> bool {
7156        self.all_diff_hunks_expanded
7157    }
7158
7159    /// Visually annotates a position or range with the `Debug` representation of a value. The
7160    /// callsite of this function is used as a key - previous annotations will be removed.
7161    #[cfg(debug_assertions)]
7162    #[track_caller]
7163    pub fn debug<V, R>(&self, ranges: &R, value: V)
7164    where
7165        R: debug::ToMultiBufferDebugRanges,
7166        V: std::fmt::Debug,
7167    {
7168        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7169    }
7170
7171    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7172    /// debug annotations with the same key will be removed. The key is also used to determine the
7173    /// annotation's color.
7174    #[cfg(debug_assertions)]
7175    #[track_caller]
7176    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7177    where
7178        K: std::hash::Hash + 'static,
7179        R: debug::ToMultiBufferDebugRanges,
7180        V: std::fmt::Debug,
7181    {
7182        let text_ranges = ranges
7183            .to_multi_buffer_debug_ranges(self)
7184            .into_iter()
7185            .flat_map(|range| {
7186                self.range_to_buffer_ranges(range.start..=range.end)
7187                    .into_iter()
7188                    .map(|(buffer, range, _excerpt_id)| {
7189                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7190                    })
7191            })
7192            .collect();
7193        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7194            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7195        });
7196    }
7197
7198    fn excerpt_edits_for_diff_change(
7199        &self,
7200        buffer_state: &BufferState,
7201        diff_change_range: Range<usize>,
7202    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7203        let mut excerpt_edits = Vec::new();
7204        for locator in &buffer_state.excerpts {
7205            let mut cursor = self
7206                .excerpts
7207                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7208            cursor.seek_forward(&Some(locator), Bias::Left);
7209            if let Some(excerpt) = cursor.item()
7210                && excerpt.locator == *locator
7211            {
7212                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7213                if diff_change_range.end < excerpt_buffer_range.start
7214                    || diff_change_range.start > excerpt_buffer_range.end
7215                {
7216                    continue;
7217                }
7218                let excerpt_start = cursor.start().1;
7219                let excerpt_len = excerpt.text_summary.len;
7220                let diff_change_start_in_excerpt = diff_change_range
7221                    .start
7222                    .saturating_sub(excerpt_buffer_range.start);
7223                let diff_change_end_in_excerpt = diff_change_range
7224                    .end
7225                    .saturating_sub(excerpt_buffer_range.start);
7226                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7227                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7228                excerpt_edits.push(Edit {
7229                    old: edit_start..edit_end,
7230                    new: edit_start..edit_end,
7231                });
7232            }
7233        }
7234        excerpt_edits
7235    }
7236}
7237
7238#[cfg(any(test, feature = "test-support"))]
7239impl MultiBufferSnapshot {
7240    pub fn random_byte_range(
7241        &self,
7242        start_offset: MultiBufferOffset,
7243        rng: &mut impl rand::Rng,
7244    ) -> Range<MultiBufferOffset> {
7245        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7246        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7247        start..end
7248    }
7249
7250    #[cfg(any(test, feature = "test-support"))]
7251    fn check_invariants(&self) {
7252        let excerpts = self.excerpts.items(());
7253        let excerpt_ids = self.excerpt_ids.items(());
7254
7255        for (ix, excerpt) in excerpts.iter().enumerate() {
7256            if ix == 0 {
7257                if excerpt.locator <= Locator::min() {
7258                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7259                }
7260            } else if excerpt.locator <= excerpts[ix - 1].locator {
7261                panic!("excerpts are out-of-order: {:?}", excerpts);
7262            }
7263        }
7264
7265        for (ix, entry) in excerpt_ids.iter().enumerate() {
7266            if ix == 0 {
7267                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7268                    panic!("invalid first excerpt id {:?}", entry.id);
7269                }
7270            } else if entry.id <= excerpt_ids[ix - 1].id {
7271                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7272            }
7273        }
7274
7275        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7276            panic!(
7277                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7278                self.excerpts.summary().text,
7279                self.diff_transforms.summary().input,
7280                self.diff_transforms.items(()),
7281            );
7282        }
7283
7284        let mut prev_transform: Option<&DiffTransform> = None;
7285        for item in self.diff_transforms.iter() {
7286            if let DiffTransform::BufferContent {
7287                summary,
7288                inserted_hunk_info,
7289            } = item
7290            {
7291                if let Some(DiffTransform::BufferContent {
7292                    inserted_hunk_info: prev_inserted_hunk_info,
7293                    ..
7294                }) = prev_transform
7295                    && *inserted_hunk_info == *prev_inserted_hunk_info
7296                {
7297                    panic!(
7298                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7299                        self.diff_transforms.items(())
7300                    );
7301                }
7302                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7303                    panic!("empty buffer content transform");
7304                }
7305            }
7306            prev_transform = Some(item);
7307        }
7308    }
7309}
7310
7311impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7312where
7313    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7314    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7315{
7316    #[instrument(skip_all)]
7317    fn seek(&mut self, position: &MBD) {
7318        let position = OutputDimension(*position);
7319        self.cached_region.take();
7320        self.diff_transforms.seek(&position, Bias::Right);
7321        if self.diff_transforms.item().is_none()
7322            && self.diff_transforms.start().output_dimension == position
7323        {
7324            self.diff_transforms.prev();
7325        }
7326
7327        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7328        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7329            let overshoot = position - self.diff_transforms.start().output_dimension;
7330            excerpt_position += overshoot;
7331        }
7332
7333        self.excerpts.seek(&excerpt_position, Bias::Right);
7334        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7335            self.excerpts.prev();
7336        }
7337    }
7338
7339    fn seek_forward(&mut self, position: &MBD) {
7340        let position = OutputDimension(*position);
7341        self.cached_region.take();
7342        self.diff_transforms.seek_forward(&position, Bias::Right);
7343        if self.diff_transforms.item().is_none()
7344            && self.diff_transforms.start().output_dimension == position
7345        {
7346            self.diff_transforms.prev();
7347        }
7348
7349        let overshoot = position - self.diff_transforms.start().output_dimension;
7350        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7351        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7352            excerpt_position += overshoot;
7353        }
7354
7355        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7356        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7357            self.excerpts.prev();
7358        }
7359    }
7360
7361    fn next_excerpt(&mut self) {
7362        self.excerpts.next();
7363        self.seek_to_start_of_current_excerpt();
7364    }
7365
7366    fn prev_excerpt(&mut self) {
7367        self.excerpts.prev();
7368        self.seek_to_start_of_current_excerpt();
7369    }
7370
7371    fn seek_to_start_of_current_excerpt(&mut self) {
7372        self.cached_region.take();
7373
7374        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7375            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7376            && self.diff_transforms.next_item().is_some()
7377        {
7378            self.diff_transforms.next();
7379        }
7380    }
7381
7382    fn next_excerpt_forwards(&mut self) {
7383        self.excerpts.next();
7384        self.seek_to_start_of_current_excerpt_forward();
7385    }
7386
7387    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7388        self.cached_region.take();
7389
7390        if self
7391            .diff_transforms
7392            .seek_forward(self.excerpts.start(), Bias::Left)
7393            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7394            && self.diff_transforms.next_item().is_some()
7395        {
7396            self.diff_transforms.next();
7397        }
7398    }
7399
7400    fn next(&mut self) {
7401        self.cached_region.take();
7402        match self
7403            .diff_transforms
7404            .end()
7405            .excerpt_dimension
7406            .cmp(&self.excerpts.end())
7407        {
7408            cmp::Ordering::Less => self.diff_transforms.next(),
7409            cmp::Ordering::Greater => self.excerpts.next(),
7410            cmp::Ordering::Equal => {
7411                self.diff_transforms.next();
7412                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7413                    || self.diff_transforms.item().is_none()
7414                {
7415                    self.excerpts.next();
7416                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7417                    self.diff_transforms.item()
7418                    && self
7419                        .excerpts
7420                        .item()
7421                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7422                {
7423                    self.excerpts.next();
7424                }
7425            }
7426        }
7427    }
7428
7429    fn prev(&mut self) {
7430        self.cached_region.take();
7431        match self
7432            .diff_transforms
7433            .start()
7434            .excerpt_dimension
7435            .cmp(self.excerpts.start())
7436        {
7437            cmp::Ordering::Less => self.excerpts.prev(),
7438            cmp::Ordering::Greater => self.diff_transforms.prev(),
7439            cmp::Ordering::Equal => {
7440                self.diff_transforms.prev();
7441                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7442                    || self.diff_transforms.item().is_none()
7443                {
7444                    self.excerpts.prev();
7445                }
7446            }
7447        }
7448    }
7449
7450    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7451        self.cached_region
7452            .get_or_init(|| self.build_region())
7453            .as_ref()
7454    }
7455
7456    fn is_at_start_of_excerpt(&mut self) -> bool {
7457        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7458            return false;
7459        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7460            return true;
7461        }
7462
7463        self.diff_transforms.prev();
7464        let prev_transform = self.diff_transforms.item();
7465        self.diff_transforms.next();
7466
7467        prev_transform.is_none_or(|next_transform| {
7468            matches!(next_transform, DiffTransform::BufferContent { .. })
7469        })
7470    }
7471
7472    fn is_at_end_of_excerpt(&self) -> bool {
7473        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7474            return false;
7475        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7476            || self.diff_transforms.item().is_none()
7477        {
7478            return true;
7479        }
7480
7481        let next_transform = self.diff_transforms.next_item();
7482        next_transform.is_none_or(|next_transform| match next_transform {
7483            DiffTransform::BufferContent { .. } => true,
7484            DiffTransform::DeletedHunk { hunk_info, .. } => self
7485                .excerpts
7486                .item()
7487                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7488        })
7489    }
7490
7491    fn main_buffer_position(&self) -> Option<BD> {
7492        let excerpt = self.excerpts.item()?;
7493        let buffer = &excerpt.buffer;
7494        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7495        let mut buffer_start = buffer_context_start;
7496        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7497        buffer_start += overshoot;
7498        Some(buffer_start)
7499    }
7500
7501    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7502        let excerpt = self.excerpts.item()?;
7503        match self.diff_transforms.item()? {
7504            DiffTransform::DeletedHunk {
7505                buffer_id,
7506                base_text_byte_range,
7507                has_trailing_newline,
7508                hunk_info,
7509                ..
7510            } => {
7511                let diff = self.diffs.get(buffer_id)?;
7512                let buffer = diff.base_text();
7513                let mut rope_cursor = buffer.as_rope().cursor(0);
7514                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7515                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7516                let mut buffer_end = buffer_start;
7517                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7518                let start = self.diff_transforms.start().output_dimension.0;
7519                let end = self.diff_transforms.end().output_dimension.0;
7520                Some(MultiBufferRegion {
7521                    buffer,
7522                    excerpt,
7523                    has_trailing_newline: *has_trailing_newline,
7524                    is_main_buffer: false,
7525                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7526                        hunk_info.hunk_secondary_status,
7527                    )),
7528                    buffer_range: buffer_start..buffer_end,
7529                    range: start..end,
7530                })
7531            }
7532            DiffTransform::BufferContent {
7533                inserted_hunk_info, ..
7534            } => {
7535                let buffer = &excerpt.buffer;
7536                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7537
7538                let mut start = self.diff_transforms.start().output_dimension.0;
7539                let mut buffer_start = buffer_context_start;
7540                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7541                    let overshoot =
7542                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7543                    start += overshoot;
7544                } else {
7545                    let overshoot =
7546                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7547                    buffer_start += overshoot;
7548                }
7549
7550                let mut end;
7551                let mut buffer_end;
7552                let has_trailing_newline;
7553                let transform_end = self.diff_transforms.end();
7554                if transform_end.excerpt_dimension < self.excerpts.end() {
7555                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7556                    end = transform_end.output_dimension.0;
7557                    buffer_end = buffer_context_start;
7558                    buffer_end += overshoot;
7559                    has_trailing_newline = false;
7560                } else {
7561                    let overshoot =
7562                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7563                    end = self.diff_transforms.start().output_dimension.0;
7564                    end += overshoot;
7565                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7566                    has_trailing_newline = excerpt.has_trailing_newline;
7567                };
7568
7569                let diff_hunk_status = inserted_hunk_info.map(|info| {
7570                    if info.is_logically_deleted {
7571                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7572                    } else {
7573                        DiffHunkStatus::added(info.hunk_secondary_status)
7574                    }
7575                });
7576
7577                Some(MultiBufferRegion {
7578                    buffer,
7579                    excerpt,
7580                    has_trailing_newline,
7581                    is_main_buffer: true,
7582                    diff_hunk_status,
7583                    buffer_range: buffer_start..buffer_end,
7584                    range: start..end,
7585                })
7586            }
7587        }
7588    }
7589
7590    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7591        let excerpt = self.excerpts.item()?;
7592        match self.diff_transforms.item()? {
7593            &DiffTransform::DeletedHunk { .. } => {
7594                let start = self.diff_transforms.start().output_dimension.0;
7595                let end = self.diff_transforms.end().output_dimension.0;
7596                Some((excerpt, start..end))
7597            }
7598            DiffTransform::BufferContent { .. } => {
7599                let mut start = self.diff_transforms.start().output_dimension.0;
7600                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7601                    let overshoot =
7602                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7603                    start += overshoot;
7604                }
7605
7606                let mut end;
7607                let transform_end = self.diff_transforms.end();
7608                if transform_end.excerpt_dimension < self.excerpts.end() {
7609                    end = transform_end.output_dimension.0;
7610                } else {
7611                    let overshoot =
7612                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7613                    end = self.diff_transforms.start().output_dimension.0;
7614                    end += overshoot;
7615                };
7616
7617                Some((excerpt, start..end))
7618            }
7619        }
7620    }
7621
7622    fn excerpt(&self) -> Option<&'a Excerpt> {
7623        self.excerpts.item()
7624    }
7625}
7626
7627impl Excerpt {
7628    fn new(
7629        id: ExcerptId,
7630        locator: Locator,
7631        buffer_id: BufferId,
7632        buffer: Arc<BufferSnapshot>,
7633        range: ExcerptRange<text::Anchor>,
7634        has_trailing_newline: bool,
7635    ) -> Self {
7636        Excerpt {
7637            id,
7638            locator,
7639            max_buffer_row: range.context.end.to_point(&buffer).row,
7640            text_summary: buffer
7641                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7642            buffer_id,
7643            buffer,
7644            range,
7645            has_trailing_newline,
7646        }
7647    }
7648
7649    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7650        let content_start = self.range.context.start.to_offset(&self.buffer);
7651        let chunks_start = content_start + range.start;
7652        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7653
7654        let has_footer = self.has_trailing_newline
7655            && range.start <= self.text_summary.len
7656            && range.end > self.text_summary.len;
7657
7658        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7659
7660        ExcerptChunks {
7661            excerpt_id: self.id,
7662            content_chunks,
7663            has_footer,
7664        }
7665    }
7666
7667    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7668        let content_start = self.range.context.start.to_offset(&self.buffer);
7669        let chunks_start = content_start + range.start;
7670        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7671        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7672        excerpt_chunks.has_footer = self.has_trailing_newline
7673            && range.start <= self.text_summary.len
7674            && range.end > self.text_summary.len;
7675    }
7676
7677    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7678        if text_anchor
7679            .cmp(&self.range.context.start, &self.buffer)
7680            .is_lt()
7681        {
7682            self.range.context.start
7683        } else if text_anchor
7684            .cmp(&self.range.context.end, &self.buffer)
7685            .is_gt()
7686        {
7687            self.range.context.end
7688        } else {
7689            text_anchor
7690        }
7691    }
7692
7693    fn contains(&self, anchor: &Anchor) -> bool {
7694        (anchor.text_anchor.buffer_id == None
7695            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7696            && self
7697                .range
7698                .context
7699                .start
7700                .cmp(&anchor.text_anchor, &self.buffer)
7701                .is_le()
7702            && self
7703                .range
7704                .context
7705                .end
7706                .cmp(&anchor.text_anchor, &self.buffer)
7707                .is_ge()
7708    }
7709
7710    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7711    fn buffer_start_offset(&self) -> BufferOffset {
7712        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7713    }
7714
7715    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7716    fn buffer_end_offset(&self) -> BufferOffset {
7717        self.buffer_start_offset() + self.text_summary.len
7718    }
7719}
7720
7721impl<'a> MultiBufferExcerpt<'a> {
7722    pub fn id(&self) -> ExcerptId {
7723        self.excerpt.id
7724    }
7725
7726    pub fn buffer_id(&self) -> BufferId {
7727        self.excerpt.buffer_id
7728    }
7729
7730    pub fn start_anchor(&self) -> Anchor {
7731        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7732    }
7733
7734    pub fn end_anchor(&self) -> Anchor {
7735        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7736    }
7737
7738    pub fn buffer(&self) -> &'a BufferSnapshot {
7739        &self.excerpt.buffer
7740    }
7741
7742    pub fn buffer_range(&self) -> Range<BufferOffset> {
7743        self.buffer_offset
7744            ..BufferOffset(
7745                self.excerpt
7746                    .range
7747                    .context
7748                    .end
7749                    .to_offset(&self.excerpt.buffer.text),
7750            )
7751    }
7752
7753    pub fn start_offset(&self) -> MultiBufferOffset {
7754        self.offset
7755    }
7756
7757    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7758    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7759        self.map_range_to_buffer(offset..offset).start
7760    }
7761
7762    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7763    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7764        self.diff_transforms
7765            .seek(&OutputDimension(range.start), Bias::Right);
7766        let start = self.map_offset_to_buffer_internal(range.start);
7767        let end = if range.end > range.start {
7768            self.diff_transforms
7769                .seek_forward(&OutputDimension(range.end), Bias::Right);
7770            self.map_offset_to_buffer_internal(range.end)
7771        } else {
7772            start
7773        };
7774        start..end
7775    }
7776
7777    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7778        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7779        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7780            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7781        };
7782        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7783        self.buffer_offset + offset_in_excerpt
7784    }
7785
7786    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7787    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7788        self.map_range_from_buffer(buffer_offset..buffer_offset)
7789            .start
7790    }
7791
7792    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7793    pub fn map_range_from_buffer(
7794        &mut self,
7795        buffer_range: Range<BufferOffset>,
7796    ) -> Range<MultiBufferOffset> {
7797        if buffer_range.start < self.buffer_offset {
7798            log::warn!(
7799                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7800            );
7801            return self.offset..self.offset;
7802        }
7803        let overshoot = buffer_range.start - self.buffer_offset;
7804        let excerpt_offset = self.excerpt_offset + overshoot;
7805        let excerpt_seek_dim = excerpt_offset;
7806        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7807        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7808            log::warn!(
7809                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7810            );
7811            return self.offset..self.offset;
7812        }
7813        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7814        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7815
7816        let end = if buffer_range.start < buffer_range.end {
7817            let overshoot = buffer_range.end - self.buffer_offset;
7818            let excerpt_offset = self.excerpt_offset + overshoot;
7819            let excerpt_seek_dim = excerpt_offset;
7820            self.diff_transforms
7821                .seek_forward(&excerpt_seek_dim, Bias::Right);
7822            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7823            // todo(lw): Clamp end to the excerpt boundaries
7824            self.diff_transforms.start().output_dimension.0 + overshoot
7825        } else {
7826            start
7827        };
7828
7829        start..end
7830    }
7831
7832    /// Returns true if the entirety of the given range is in the buffer's excerpt
7833    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7834        range.start >= self.excerpt.buffer_start_offset()
7835            && range.end <= self.excerpt.buffer_end_offset()
7836    }
7837
7838    /// Returns true if any part of the given range is in the buffer's excerpt
7839    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7840        range.start <= self.excerpt.buffer_end_offset()
7841            && range.end >= self.excerpt.buffer_start_offset()
7842    }
7843
7844    pub fn max_buffer_row(&self) -> u32 {
7845        self.excerpt.max_buffer_row
7846    }
7847}
7848
7849impl ExcerptId {
7850    pub fn min() -> Self {
7851        Self(0)
7852    }
7853
7854    pub fn max() -> Self {
7855        Self(u32::MAX)
7856    }
7857
7858    pub fn to_proto(self) -> u64 {
7859        self.0 as _
7860    }
7861
7862    pub fn from_proto(proto: u64) -> Self {
7863        Self(proto as _)
7864    }
7865
7866    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7867        let a = snapshot.excerpt_locator_for_id(*self);
7868        let b = snapshot.excerpt_locator_for_id(*other);
7869        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7870    }
7871}
7872
7873impl From<ExcerptId> for usize {
7874    fn from(val: ExcerptId) -> Self {
7875        val.0 as usize
7876    }
7877}
7878
7879impl fmt::Debug for Excerpt {
7880    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7881        f.debug_struct("Excerpt")
7882            .field("id", &self.id)
7883            .field("locator", &self.locator)
7884            .field("buffer_id", &self.buffer_id)
7885            .field("range", &self.range)
7886            .field("text_summary", &self.text_summary)
7887            .field("has_trailing_newline", &self.has_trailing_newline)
7888            .finish()
7889    }
7890}
7891
7892impl sum_tree::Item for Excerpt {
7893    type Summary = ExcerptSummary;
7894
7895    fn summary(&self, _cx: ()) -> Self::Summary {
7896        let mut text = self.text_summary;
7897        if self.has_trailing_newline {
7898            text += TextSummary::from("\n");
7899        }
7900        ExcerptSummary {
7901            excerpt_id: self.id,
7902            excerpt_locator: self.locator.clone(),
7903            widest_line_number: self.max_buffer_row,
7904            text: text.into(),
7905            count: 1,
7906        }
7907    }
7908}
7909
7910impl sum_tree::Item for ExcerptIdMapping {
7911    type Summary = ExcerptId;
7912
7913    fn summary(&self, _cx: ()) -> Self::Summary {
7914        self.id
7915    }
7916}
7917
7918impl sum_tree::KeyedItem for ExcerptIdMapping {
7919    type Key = ExcerptId;
7920
7921    fn key(&self) -> Self::Key {
7922        self.id
7923    }
7924}
7925
7926impl DiffTransform {
7927    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7928        match self {
7929            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7930            DiffTransform::BufferContent {
7931                inserted_hunk_info, ..
7932            } => *inserted_hunk_info,
7933        }
7934    }
7935}
7936
7937impl sum_tree::Item for DiffTransform {
7938    type Summary = DiffTransformSummary;
7939
7940    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7941        match self {
7942            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7943                input: *summary,
7944                output: *summary,
7945            },
7946            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7947                input: MBTextSummary::default(),
7948                output: summary.into(),
7949            },
7950        }
7951    }
7952}
7953
7954impl DiffTransformSummary {
7955    fn excerpt_len(&self) -> ExcerptOffset {
7956        ExcerptDimension(self.input.len)
7957    }
7958}
7959
7960impl sum_tree::ContextLessSummary for DiffTransformSummary {
7961    fn zero() -> Self {
7962        DiffTransformSummary {
7963            input: MBTextSummary::default(),
7964            output: MBTextSummary::default(),
7965        }
7966    }
7967
7968    fn add_summary(&mut self, other: &Self) {
7969        self.input += other.input;
7970        self.output += other.output;
7971    }
7972}
7973
7974impl sum_tree::ContextLessSummary for ExcerptId {
7975    fn zero() -> Self {
7976        Self(0)
7977    }
7978
7979    fn add_summary(&mut self, summary: &Self) {
7980        *self = cmp::max(*self, *summary);
7981    }
7982}
7983
7984impl sum_tree::ContextLessSummary for ExcerptSummary {
7985    fn zero() -> Self {
7986        Self::default()
7987    }
7988
7989    fn add_summary(&mut self, summary: &Self) {
7990        debug_assert!(
7991            summary.excerpt_locator > self.excerpt_locator
7992                || self.excerpt_locator == Locator::min(),
7993            "Excerpt locators must be in ascending order: {:?} > {:?}",
7994            summary.excerpt_locator,
7995            self.excerpt_locator
7996        );
7997        self.excerpt_locator = summary.excerpt_locator.clone();
7998        self.text += summary.text;
7999        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
8000        self.count += summary.count;
8001    }
8002}
8003
8004impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
8005    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
8006        Ord::cmp(&Some(self), cursor_location)
8007    }
8008}
8009
8010impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
8011    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
8012        Ord::cmp(self, &cursor_location.excerpt_locator)
8013    }
8014}
8015
8016impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
8017where
8018    MBD: MultiBufferDimension + Default,
8019{
8020    fn zero(_: ()) -> Self {
8021        ExcerptDimension(MBD::default())
8022    }
8023
8024    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8025        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
8026    }
8027}
8028
8029impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
8030    fn zero(_cx: ()) -> Self {
8031        Default::default()
8032    }
8033
8034    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8035        *self = Some(&summary.excerpt_locator);
8036    }
8037}
8038
8039impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
8040    fn zero(_cx: ()) -> Self {
8041        Default::default()
8042    }
8043
8044    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
8045        *self = Some(summary.excerpt_id);
8046    }
8047}
8048
8049#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8050struct OutputDimension<T>(T);
8051
8052impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8053    fn eq(&self, other: &T) -> bool {
8054        self.0 == *other
8055    }
8056}
8057
8058impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8059    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8060        self.0.partial_cmp(other)
8061    }
8062}
8063
8064impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8065where
8066    T: ops::Sub<U, Output = R>,
8067{
8068    type Output = R;
8069
8070    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8071        self.0 - other.0
8072    }
8073}
8074
8075impl<R, T, U> ops::Add<U> for OutputDimension<T>
8076where
8077    T: ops::Add<U, Output = R>,
8078{
8079    type Output = OutputDimension<R>;
8080
8081    fn add(self, other: U) -> Self::Output {
8082        OutputDimension(self.0 + other)
8083    }
8084}
8085
8086impl<T, U> AddAssign<U> for OutputDimension<T>
8087where
8088    T: AddAssign<U>,
8089{
8090    fn add_assign(&mut self, other: U) {
8091        self.0 += other;
8092    }
8093}
8094
8095impl<T, U> SubAssign<U> for OutputDimension<T>
8096where
8097    T: SubAssign<U>,
8098{
8099    fn sub_assign(&mut self, other: U) {
8100        self.0 -= other;
8101    }
8102}
8103
8104#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8105struct ExcerptDimension<T>(T);
8106
8107impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8108    fn eq(&self, other: &T) -> bool {
8109        self.0 == *other
8110    }
8111}
8112
8113impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8114    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8115        self.0.partial_cmp(other)
8116    }
8117}
8118
8119impl ExcerptOffset {
8120    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8121        self.0.saturating_sub(other.0)
8122    }
8123}
8124
8125impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8126where
8127    T: ops::Sub<U, Output = R>,
8128{
8129    type Output = R;
8130
8131    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8132        self.0 - other.0
8133    }
8134}
8135
8136impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8137where
8138    T: ops::Add<U, Output = R>,
8139{
8140    type Output = ExcerptDimension<R>;
8141
8142    fn add(self, other: U) -> Self::Output {
8143        ExcerptDimension(self.0 + other)
8144    }
8145}
8146
8147impl<T, U> AddAssign<U> for ExcerptDimension<T>
8148where
8149    T: AddAssign<U>,
8150{
8151    fn add_assign(&mut self, other: U) {
8152        self.0 += other;
8153    }
8154}
8155
8156impl<T, U> SubAssign<U> for ExcerptDimension<T>
8157where
8158    T: SubAssign<U>,
8159{
8160    fn sub_assign(&mut self, other: U) {
8161        self.0 -= other;
8162    }
8163}
8164
8165impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8166    fn zero(_: ()) -> Self {
8167        MultiBufferOffset::ZERO
8168    }
8169
8170    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8171        *self += summary.output.len;
8172    }
8173}
8174
8175impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8176    for ExcerptDimension<MBD>
8177where
8178    MBD: MultiBufferDimension + Ord,
8179{
8180    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8181        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8182    }
8183}
8184
8185impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8186    for ExcerptDimension<MBD>
8187where
8188    MBD: MultiBufferDimension + Ord,
8189{
8190    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8191        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8192    }
8193}
8194
8195impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8196    for ExcerptDimension<MBD>
8197{
8198    fn zero(_: ()) -> Self {
8199        ExcerptDimension(MBD::default())
8200    }
8201
8202    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8203        self.0.add_mb_text_summary(&summary.input)
8204    }
8205}
8206
8207impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8208    for OutputDimension<MBD>
8209where
8210    MBD: MultiBufferDimension + Ord,
8211{
8212    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8213        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8214    }
8215}
8216
8217impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8218    for OutputDimension<MBD>
8219{
8220    fn zero(_: ()) -> Self {
8221        OutputDimension(MBD::default())
8222    }
8223
8224    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8225        self.0.add_mb_text_summary(&summary.output)
8226    }
8227}
8228
8229impl MultiBufferRows<'_> {
8230    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8231        self.point = Point::new(row, 0);
8232        self.cursor.seek(&self.point);
8233    }
8234}
8235
8236impl Iterator for MultiBufferRows<'_> {
8237    type Item = RowInfo;
8238
8239    fn next(&mut self) -> Option<Self::Item> {
8240        if self.is_empty && self.point.row == 0 {
8241            self.point += Point::new(1, 0);
8242            return Some(RowInfo {
8243                buffer_id: None,
8244                buffer_row: Some(0),
8245                multibuffer_row: Some(MultiBufferRow(0)),
8246                diff_status: None,
8247                expand_info: None,
8248                wrapped_buffer_row: None,
8249            });
8250        }
8251
8252        let mut region = self.cursor.region()?.clone();
8253        while self.point >= region.range.end {
8254            self.cursor.next();
8255            if let Some(next_region) = self.cursor.region() {
8256                region = next_region.clone();
8257            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8258                let multibuffer_row = MultiBufferRow(self.point.row);
8259                let last_excerpt = self
8260                    .cursor
8261                    .excerpts
8262                    .item()
8263                    .or(self.cursor.excerpts.prev_item())?;
8264                let last_row = last_excerpt
8265                    .range
8266                    .context
8267                    .end
8268                    .to_point(&last_excerpt.buffer)
8269                    .row;
8270
8271                let first_row = last_excerpt
8272                    .range
8273                    .context
8274                    .start
8275                    .to_point(&last_excerpt.buffer)
8276                    .row;
8277
8278                let expand_info = if self.is_singleton {
8279                    None
8280                } else {
8281                    let needs_expand_up = first_row == last_row
8282                        && last_row > 0
8283                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8284                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8285
8286                    if needs_expand_up && needs_expand_down {
8287                        Some(ExpandExcerptDirection::UpAndDown)
8288                    } else if needs_expand_up {
8289                        Some(ExpandExcerptDirection::Up)
8290                    } else if needs_expand_down {
8291                        Some(ExpandExcerptDirection::Down)
8292                    } else {
8293                        None
8294                    }
8295                    .map(|direction| ExpandInfo {
8296                        direction,
8297                        excerpt_id: last_excerpt.id,
8298                    })
8299                };
8300                self.point += Point::new(1, 0);
8301                return Some(RowInfo {
8302                    buffer_id: Some(last_excerpt.buffer_id),
8303                    buffer_row: Some(last_row),
8304                    multibuffer_row: Some(multibuffer_row),
8305                    diff_status: None,
8306                    wrapped_buffer_row: None,
8307                    expand_info,
8308                });
8309            } else {
8310                return None;
8311            };
8312        }
8313
8314        let overshoot = self.point - region.range.start;
8315        let buffer_point = region.buffer_range.start + overshoot;
8316        let expand_info = if self.is_singleton {
8317            None
8318        } else {
8319            let needs_expand_up = self.point.row == region.range.start.row
8320                && self.cursor.is_at_start_of_excerpt()
8321                && buffer_point.row > 0;
8322            let needs_expand_down = (region.excerpt.has_trailing_newline
8323                && self.point.row + 1 == region.range.end.row
8324                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8325                && self.cursor.is_at_end_of_excerpt()
8326                && buffer_point.row < region.buffer.max_point().row;
8327
8328            if needs_expand_up && needs_expand_down {
8329                Some(ExpandExcerptDirection::UpAndDown)
8330            } else if needs_expand_up {
8331                Some(ExpandExcerptDirection::Up)
8332            } else if needs_expand_down {
8333                Some(ExpandExcerptDirection::Down)
8334            } else {
8335                None
8336            }
8337            .map(|direction| ExpandInfo {
8338                direction,
8339                excerpt_id: region.excerpt.id,
8340            })
8341        };
8342
8343        let result = Some(RowInfo {
8344            buffer_id: Some(region.buffer.remote_id()),
8345            buffer_row: Some(buffer_point.row),
8346            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8347            diff_status: region
8348                .diff_hunk_status
8349                .filter(|_| self.point < region.range.end),
8350            expand_info,
8351            wrapped_buffer_row: None,
8352        });
8353        self.point += Point::new(1, 0);
8354        result
8355    }
8356}
8357
8358impl<'a> MultiBufferChunks<'a> {
8359    pub fn offset(&self) -> MultiBufferOffset {
8360        self.range.start
8361    }
8362
8363    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8364        self.diff_transforms.seek(&range.end, Bias::Right);
8365        let mut excerpt_end = self.diff_transforms.start().1;
8366        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8367            let overshoot = range.end - self.diff_transforms.start().0;
8368            excerpt_end += overshoot;
8369        }
8370
8371        self.diff_transforms.seek(&range.start, Bias::Right);
8372        let mut excerpt_start = self.diff_transforms.start().1;
8373        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8374            let overshoot = range.start - self.diff_transforms.start().0;
8375            excerpt_start += overshoot;
8376        }
8377
8378        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8379        self.buffer_chunk.take();
8380        self.range = range;
8381    }
8382
8383    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8384        self.excerpt_offset_range = new_range.clone();
8385        self.excerpts.seek(&new_range.start, Bias::Right);
8386        if let Some(excerpt) = self.excerpts.item() {
8387            let excerpt_start = *self.excerpts.start();
8388            if let Some(excerpt_chunks) = self
8389                .excerpt_chunks
8390                .as_mut()
8391                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8392            {
8393                excerpt.seek_chunks(
8394                    excerpt_chunks,
8395                    (self.excerpt_offset_range.start - excerpt_start)
8396                        ..(self.excerpt_offset_range.end - excerpt_start),
8397                );
8398            } else {
8399                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8400                    (self.excerpt_offset_range.start - excerpt_start)
8401                        ..(self.excerpt_offset_range.end - excerpt_start),
8402                    self.language_aware,
8403                ));
8404            }
8405        } else {
8406            self.excerpt_chunks = None;
8407        }
8408    }
8409
8410    #[ztracing::instrument(skip_all)]
8411    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8412        loop {
8413            if self.excerpt_offset_range.is_empty() {
8414                return None;
8415            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8416                self.excerpt_offset_range.start += chunk.text.len();
8417                return Some(chunk);
8418            } else {
8419                self.excerpts.next();
8420                let excerpt = self.excerpts.item()?;
8421                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8422                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8423                    self.language_aware,
8424                ));
8425            }
8426        }
8427    }
8428}
8429
8430impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8431    type Item = &'a str;
8432
8433    fn next(&mut self) -> Option<Self::Item> {
8434        let mut region = self.cursor.region()?;
8435        if self.offset == region.range.start {
8436            self.cursor.prev();
8437            region = self.cursor.region()?;
8438            let start_overshoot = self.start.saturating_sub(region.range.start);
8439            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8440                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8441            ));
8442        }
8443
8444        if self.offset == region.range.end && region.has_trailing_newline {
8445            self.offset -= 1;
8446            Some("\n")
8447        } else {
8448            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8449            self.offset -= chunk.len();
8450            Some(chunk)
8451        }
8452    }
8453}
8454
8455impl<'a> Iterator for MultiBufferChunks<'a> {
8456    type Item = Chunk<'a>;
8457
8458    #[ztracing::instrument(skip_all)]
8459    fn next(&mut self) -> Option<Chunk<'a>> {
8460        if self.range.start >= self.range.end {
8461            return None;
8462        }
8463        if self.range.start == self.diff_transforms.end().0 {
8464            self.diff_transforms.next();
8465        }
8466
8467        let diff_transform_start = self.diff_transforms.start().0;
8468        let diff_transform_end = self.diff_transforms.end().0;
8469        debug_assert!(
8470            self.range.start < diff_transform_end,
8471            "{:?} < {:?} of ({1:?}..{2:?})",
8472            self.range.start,
8473            diff_transform_end,
8474            diff_transform_start
8475        );
8476
8477        let diff_transform = self.diff_transforms.item()?;
8478        match diff_transform {
8479            DiffTransform::BufferContent { .. } => {
8480                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8481                    chunk
8482                } else {
8483                    let chunk = self.next_excerpt_chunk().unwrap();
8484                    self.buffer_chunk.insert(chunk)
8485                };
8486
8487                let chunk_end = self.range.start + chunk.text.len();
8488                let diff_transform_end = diff_transform_end.min(self.range.end);
8489
8490                if diff_transform_end < chunk_end {
8491                    let split_idx = diff_transform_end - self.range.start;
8492                    let (before, after) = chunk.text.split_at(split_idx);
8493                    self.range.start = diff_transform_end;
8494                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8495                    let chars = chunk.chars & mask;
8496                    let tabs = chunk.tabs & mask;
8497                    let newlines = chunk.newlines & mask;
8498
8499                    chunk.text = after;
8500                    chunk.chars = chunk.chars >> split_idx;
8501                    chunk.tabs = chunk.tabs >> split_idx;
8502                    chunk.newlines = chunk.newlines >> split_idx;
8503
8504                    Some(Chunk {
8505                        text: before,
8506                        chars,
8507                        tabs,
8508                        newlines,
8509                        ..chunk.clone()
8510                    })
8511                } else {
8512                    self.range.start = chunk_end;
8513                    self.buffer_chunk.take()
8514                }
8515            }
8516            DiffTransform::DeletedHunk {
8517                buffer_id,
8518                base_text_byte_range,
8519                has_trailing_newline,
8520                ..
8521            } => {
8522                let base_text_start =
8523                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8524                let base_text_end =
8525                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8526                let base_text_end = base_text_end.min(base_text_byte_range.end);
8527
8528                let mut chunks = if let Some((_, mut chunks)) = self
8529                    .diff_base_chunks
8530                    .take()
8531                    .filter(|(id, _)| id == buffer_id)
8532                {
8533                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8534                    {
8535                        chunks.seek(base_text_start..base_text_end);
8536                    }
8537                    chunks
8538                } else {
8539                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8540                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8541                };
8542
8543                let chunk = if let Some(chunk) = chunks.next() {
8544                    self.range.start += chunk.text.len();
8545                    self.diff_base_chunks = Some((*buffer_id, chunks));
8546                    chunk
8547                } else {
8548                    debug_assert!(has_trailing_newline);
8549                    self.range.start += "\n".len();
8550                    Chunk {
8551                        text: "\n",
8552                        chars: 1u128,
8553                        newlines: 1u128,
8554                        ..Default::default()
8555                    }
8556                };
8557                Some(chunk)
8558            }
8559        }
8560    }
8561}
8562
8563impl MultiBufferBytes<'_> {
8564    fn consume(&mut self, len: usize) {
8565        self.range.start += len;
8566        self.chunk = &self.chunk[len..];
8567
8568        if !self.range.is_empty() && self.chunk.is_empty() {
8569            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8570                self.chunk = chunk;
8571            } else if self.has_trailing_newline {
8572                self.has_trailing_newline = false;
8573                self.chunk = b"\n";
8574            } else {
8575                self.cursor.next();
8576                if let Some(region) = self.cursor.region() {
8577                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8578                        region.buffer_range.start
8579                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8580                                .min(region.buffer_range.end),
8581                    );
8582                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8583                    self.excerpt_bytes = Some(excerpt_bytes);
8584                    self.has_trailing_newline =
8585                        region.has_trailing_newline && self.range.end >= region.range.end;
8586                    if self.chunk.is_empty() && self.has_trailing_newline {
8587                        self.has_trailing_newline = false;
8588                        self.chunk = b"\n";
8589                    }
8590                }
8591            }
8592        }
8593    }
8594}
8595
8596impl<'a> Iterator for MultiBufferBytes<'a> {
8597    type Item = &'a [u8];
8598
8599    fn next(&mut self) -> Option<Self::Item> {
8600        let chunk = self.chunk;
8601        if chunk.is_empty() {
8602            None
8603        } else {
8604            self.consume(chunk.len());
8605            Some(chunk)
8606        }
8607    }
8608}
8609
8610impl io::Read for MultiBufferBytes<'_> {
8611    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8612        let len = cmp::min(buf.len(), self.chunk.len());
8613        buf[..len].copy_from_slice(&self.chunk[..len]);
8614        if len > 0 {
8615            self.consume(len);
8616        }
8617        Ok(len)
8618    }
8619}
8620
8621impl io::Read for ReversedMultiBufferBytes<'_> {
8622    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8623        let len = cmp::min(buf.len(), self.chunk.len());
8624        buf[..len].copy_from_slice(&self.chunk[..len]);
8625        buf[..len].reverse();
8626        if len > 0 {
8627            self.range.end -= len;
8628            self.chunk = &self.chunk[..self.chunk.len() - len];
8629            if !self.range.is_empty()
8630                && self.chunk.is_empty()
8631                && let Some(chunk) = self.chunks.next()
8632            {
8633                self.chunk = chunk.as_bytes();
8634            }
8635        }
8636        Ok(len)
8637    }
8638}
8639
8640impl<'a> Iterator for ExcerptChunks<'a> {
8641    type Item = Chunk<'a>;
8642
8643    fn next(&mut self) -> Option<Self::Item> {
8644        if let Some(chunk) = self.content_chunks.next() {
8645            return Some(chunk);
8646        }
8647
8648        if self.has_footer {
8649            let text = "\n";
8650            let chars = 0b1;
8651            let newlines = 0b1;
8652            self.has_footer = false;
8653            return Some(Chunk {
8654                text,
8655                chars,
8656                newlines,
8657                ..Default::default()
8658            });
8659        }
8660
8661        None
8662    }
8663}
8664
8665impl ToOffset for Point {
8666    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8667        snapshot.point_to_offset(*self)
8668    }
8669    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8670        snapshot.point_to_offset_utf16(*self)
8671    }
8672}
8673
8674impl ToOffset for MultiBufferOffset {
8675    #[track_caller]
8676    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8677        assert!(
8678            *self <= snapshot.len(),
8679            "offset {} is greater than the snapshot.len() {}",
8680            self.0,
8681            snapshot.len().0,
8682        );
8683        *self
8684    }
8685    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8686        snapshot.offset_to_offset_utf16(*self)
8687    }
8688}
8689
8690impl ToOffset for MultiBufferOffsetUtf16 {
8691    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8692        snapshot.offset_utf16_to_offset(*self)
8693    }
8694
8695    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8696        *self
8697    }
8698}
8699
8700impl ToOffset for PointUtf16 {
8701    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8702        snapshot.point_utf16_to_offset(*self)
8703    }
8704    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8705        snapshot.point_utf16_to_offset_utf16(*self)
8706    }
8707}
8708
8709impl ToPoint for MultiBufferOffset {
8710    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8711        snapshot.offset_to_point(*self)
8712    }
8713    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8714        snapshot.offset_to_point_utf16(*self)
8715    }
8716}
8717
8718impl ToPoint for Point {
8719    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8720        *self
8721    }
8722    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8723        snapshot.point_to_point_utf16(*self)
8724    }
8725}
8726
8727impl ToPoint for PointUtf16 {
8728    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8729        snapshot.point_utf16_to_point(*self)
8730    }
8731    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8732        *self
8733    }
8734}
8735
8736impl From<ExcerptId> for EntityId {
8737    fn from(id: ExcerptId) -> Self {
8738        EntityId::from(id.0 as u64)
8739    }
8740}
8741
8742#[cfg(debug_assertions)]
8743pub mod debug {
8744    use super::*;
8745
8746    pub trait ToMultiBufferDebugRanges {
8747        fn to_multi_buffer_debug_ranges(
8748            &self,
8749            snapshot: &MultiBufferSnapshot,
8750        ) -> Vec<Range<MultiBufferOffset>>;
8751    }
8752
8753    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8754        fn to_multi_buffer_debug_ranges(
8755            &self,
8756            snapshot: &MultiBufferSnapshot,
8757        ) -> Vec<Range<MultiBufferOffset>> {
8758            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8759        }
8760    }
8761
8762    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8763        fn to_multi_buffer_debug_ranges(
8764            &self,
8765            snapshot: &MultiBufferSnapshot,
8766        ) -> Vec<Range<MultiBufferOffset>> {
8767            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8768                .to_multi_buffer_debug_ranges(snapshot)
8769        }
8770    }
8771
8772    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8773        fn to_multi_buffer_debug_ranges(
8774            &self,
8775            snapshot: &MultiBufferSnapshot,
8776        ) -> Vec<Range<MultiBufferOffset>> {
8777            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8778        }
8779    }
8780
8781    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8782        fn to_multi_buffer_debug_ranges(
8783            &self,
8784            snapshot: &MultiBufferSnapshot,
8785        ) -> Vec<Range<MultiBufferOffset>> {
8786            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8787        }
8788    }
8789
8790    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8791        fn to_multi_buffer_debug_ranges(
8792            &self,
8793            snapshot: &MultiBufferSnapshot,
8794        ) -> Vec<Range<MultiBufferOffset>> {
8795            self.iter()
8796                .map(|item| {
8797                    let offset = item.to_offset(snapshot);
8798                    offset..offset
8799                })
8800                .collect()
8801        }
8802    }
8803
8804    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8805        fn to_multi_buffer_debug_ranges(
8806            &self,
8807            snapshot: &MultiBufferSnapshot,
8808        ) -> Vec<Range<MultiBufferOffset>> {
8809            self.iter()
8810                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8811                .collect()
8812        }
8813    }
8814}