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