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