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