multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    // all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum MultiOrSingleBufferOffsetRange {
  83    Single(Range<usize>),
  84    Multi(Range<usize>),
  85}
  86
  87#[derive(Clone, Debug, PartialEq, Eq)]
  88pub enum Event {
  89    ExcerptsAdded {
  90        buffer: Entity<Buffer>,
  91        predecessor: ExcerptId,
  92        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  93    },
  94    ExcerptsRemoved {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsExpanded {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsEdited {
 101        excerpt_ids: Vec<ExcerptId>,
 102        buffer_ids: Vec<BufferId>,
 103    },
 104    DiffHunksToggled,
 105    Edited {
 106        singleton_buffer_edited: bool,
 107        edited_buffer: Option<Entity<Buffer>>,
 108    },
 109    TransactionUndone {
 110        transaction_id: TransactionId,
 111    },
 112    Reloaded,
 113    ReloadNeeded,
 114
 115    LanguageChanged(BufferId),
 116    CapabilityChanged,
 117    Reparsed(BufferId),
 118    Saved,
 119    FileHandleChanged,
 120    Closed,
 121    Discarded,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124}
 125
 126/// A diff hunk, representing a range of consequent lines in a multibuffer.
 127#[derive(Debug, Clone, PartialEq, Eq)]
 128pub struct MultiBufferDiffHunk {
 129    /// The row range in the multibuffer where this diff hunk appears.
 130    pub row_range: Range<MultiBufferRow>,
 131    /// The buffer ID that this hunk belongs to.
 132    pub buffer_id: BufferId,
 133    /// The range of the underlying buffer that this hunk corresponds to.
 134    pub buffer_range: Range<text::Anchor>,
 135    /// The excerpt that contains the diff hunk.
 136    pub excerpt_id: ExcerptId,
 137    /// The range within the buffer's diff base that this hunk corresponds to.
 138    pub diff_base_byte_range: Range<usize>,
 139    /// Whether or not this hunk also appears in the 'secondary diff'.
 140    pub secondary_status: DiffHunkSecondaryStatus,
 141}
 142
 143impl MultiBufferDiffHunk {
 144    pub fn status(&self) -> DiffHunkStatus {
 145        let kind = if self.buffer_range.start == self.buffer_range.end {
 146            DiffHunkStatusKind::Deleted
 147        } else if self.diff_base_byte_range.is_empty() {
 148            DiffHunkStatusKind::Added
 149        } else {
 150            DiffHunkStatusKind::Modified
 151        };
 152        DiffHunkStatus {
 153            kind,
 154            secondary: self.secondary_status,
 155        }
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (0..0)
 160            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 161    }
 162}
 163
 164#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 165pub struct PathKey {
 166    namespace: &'static str,
 167    path: Arc<Path>,
 168}
 169
 170impl PathKey {
 171    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 172        Self { namespace, path }
 173    }
 174
 175    pub fn path(&self) -> &Arc<Path> {
 176        &self.path
 177    }
 178}
 179
 180pub type MultiBufferPoint = Point;
 181type ExcerptOffset = TypedOffset<Excerpt>;
 182type ExcerptPoint = TypedPoint<Excerpt>;
 183
 184#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 185#[serde(transparent)]
 186pub struct MultiBufferRow(pub u32);
 187
 188impl MultiBufferRow {
 189    pub const MIN: Self = Self(0);
 190    pub const MAX: Self = Self(u32::MAX);
 191}
 192
 193impl std::ops::Add<usize> for MultiBufferRow {
 194    type Output = Self;
 195
 196    fn add(self, rhs: usize) -> Self::Output {
 197        MultiBufferRow(self.0 + rhs as u32)
 198    }
 199}
 200
 201#[derive(Clone)]
 202struct History {
 203    next_transaction_id: TransactionId,
 204    undo_stack: Vec<Transaction>,
 205    redo_stack: Vec<Transaction>,
 206    transaction_depth: usize,
 207    group_interval: Duration,
 208}
 209
 210#[derive(Clone)]
 211struct Transaction {
 212    id: TransactionId,
 213    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 214    first_edit_at: Instant,
 215    last_edit_at: Instant,
 216    suppress_grouping: bool,
 217}
 218
 219pub trait ToOffset: 'static + fmt::Debug {
 220    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 221}
 222
 223pub trait ToOffsetUtf16: 'static + fmt::Debug {
 224    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 225}
 226
 227pub trait ToPoint: 'static + fmt::Debug {
 228    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 229}
 230
 231pub trait ToPointUtf16: 'static + fmt::Debug {
 232    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 233}
 234
 235struct BufferState {
 236    buffer: Entity<Buffer>,
 237    last_version: clock::Global,
 238    last_non_text_state_update_count: usize,
 239    excerpts: Vec<Locator>,
 240    _subscriptions: [gpui::Subscription; 2],
 241}
 242
 243struct DiffState {
 244    diff: Entity<BufferDiff>,
 245    _subscription: gpui::Subscription,
 246}
 247
 248impl DiffState {
 249    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 250        DiffState {
 251            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 252                BufferDiffEvent::DiffChanged { changed_range } => {
 253                    if let Some(changed_range) = changed_range.clone() {
 254                        this.buffer_diff_changed(diff, changed_range, cx)
 255                    }
 256                }
 257                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 258                _ => {}
 259            }),
 260            diff,
 261        }
 262    }
 263}
 264
 265/// The contents of a [`MultiBuffer`] at a single point in time.
 266#[derive(Clone, Default)]
 267pub struct MultiBufferSnapshot {
 268    singleton: bool,
 269    excerpts: SumTree<Excerpt>,
 270    excerpt_ids: SumTree<ExcerptIdMapping>,
 271    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 272    diff_transforms: SumTree<DiffTransform>,
 273    trailing_excerpt_update_count: usize,
 274    all_diff_hunks_expanded: bool,
 275    non_text_state_update_count: usize,
 276    edit_count: usize,
 277    is_dirty: bool,
 278    has_deleted_file: bool,
 279    has_conflict: bool,
 280    show_headers: bool,
 281}
 282
 283#[derive(Debug, Clone)]
 284enum DiffTransform {
 285    BufferContent {
 286        summary: TextSummary,
 287        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 288    },
 289    DeletedHunk {
 290        summary: TextSummary,
 291        buffer_id: BufferId,
 292        hunk_info: DiffTransformHunkInfo,
 293        base_text_byte_range: Range<usize>,
 294        has_trailing_newline: bool,
 295    },
 296}
 297
 298#[derive(Clone, Copy, Debug)]
 299struct DiffTransformHunkInfo {
 300    excerpt_id: ExcerptId,
 301    hunk_start_anchor: text::Anchor,
 302    hunk_secondary_status: DiffHunkSecondaryStatus,
 303}
 304
 305impl Eq for DiffTransformHunkInfo {}
 306
 307impl PartialEq for DiffTransformHunkInfo {
 308    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 309        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 310    }
 311}
 312
 313impl std::hash::Hash for DiffTransformHunkInfo {
 314    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 315        self.excerpt_id.hash(state);
 316        self.hunk_start_anchor.hash(state);
 317    }
 318}
 319
 320#[derive(Clone)]
 321pub struct ExcerptInfo {
 322    pub id: ExcerptId,
 323    pub buffer: BufferSnapshot,
 324    pub buffer_id: BufferId,
 325    pub range: ExcerptRange<text::Anchor>,
 326    pub end_row: MultiBufferRow,
 327}
 328
 329impl std::fmt::Debug for ExcerptInfo {
 330    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 331        f.debug_struct(type_name::<Self>())
 332            .field("id", &self.id)
 333            .field("buffer_id", &self.buffer_id)
 334            .field("path", &self.buffer.file().map(|f| f.path()))
 335            .field("range", &self.range)
 336            .finish()
 337    }
 338}
 339
 340/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 341#[derive(Debug)]
 342pub struct ExcerptBoundary {
 343    pub prev: Option<ExcerptInfo>,
 344    pub next: Option<ExcerptInfo>,
 345    /// The row in the `MultiBuffer` where the boundary is located
 346    pub row: MultiBufferRow,
 347}
 348
 349impl ExcerptBoundary {
 350    pub fn starts_new_buffer(&self) -> bool {
 351        match (self.prev.as_ref(), self.next.as_ref()) {
 352            (None, _) => true,
 353            (Some(_), None) => false,
 354            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 355        }
 356    }
 357}
 358
 359#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 360pub struct RowInfo {
 361    pub buffer_id: Option<BufferId>,
 362    pub buffer_row: Option<u32>,
 363    pub multibuffer_row: Option<MultiBufferRow>,
 364    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 365}
 366
 367/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 368#[derive(Clone)]
 369struct Excerpt {
 370    /// The unique identifier for this excerpt
 371    id: ExcerptId,
 372    /// The location of the excerpt in the [`MultiBuffer`]
 373    locator: Locator,
 374    /// The buffer being excerpted
 375    buffer_id: BufferId,
 376    /// A snapshot of the buffer being excerpted
 377    buffer: BufferSnapshot,
 378    /// The range of the buffer to be shown in the excerpt
 379    range: ExcerptRange<text::Anchor>,
 380    /// The last row in the excerpted slice of the buffer
 381    max_buffer_row: BufferRow,
 382    /// A summary of the text in the excerpt
 383    text_summary: TextSummary,
 384    has_trailing_newline: bool,
 385}
 386
 387/// A public view into an `Excerpt` in a [`MultiBuffer`].
 388///
 389/// Contains methods for getting the [`Buffer`] of the excerpt,
 390/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 391#[derive(Clone)]
 392pub struct MultiBufferExcerpt<'a> {
 393    excerpt: &'a Excerpt,
 394    diff_transforms:
 395        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 396    offset: usize,
 397    excerpt_offset: ExcerptDimension<usize>,
 398    buffer_offset: usize,
 399}
 400
 401#[derive(Clone, Debug)]
 402struct ExcerptIdMapping {
 403    id: ExcerptId,
 404    locator: Locator,
 405}
 406
 407/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 408/// These ranges are relative to the buffer itself
 409#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 410pub struct ExcerptRange<T> {
 411    /// The full range of text to be shown in the excerpt.
 412    pub context: Range<T>,
 413    /// The primary range of text to be highlighted in the excerpt.
 414    /// In a multi-buffer search, this would be the text that matched the search
 415    pub primary: Option<Range<T>>,
 416}
 417
 418#[derive(Clone, Debug, Default)]
 419pub struct ExcerptSummary {
 420    excerpt_id: ExcerptId,
 421    /// The location of the last [`Excerpt`] being summarized
 422    excerpt_locator: Locator,
 423    widest_line_number: u32,
 424    text: TextSummary,
 425}
 426
 427#[derive(Debug, Clone)]
 428pub struct DiffTransformSummary {
 429    input: TextSummary,
 430    output: TextSummary,
 431}
 432
 433#[derive(Clone)]
 434pub struct MultiBufferRows<'a> {
 435    point: Point,
 436    is_empty: bool,
 437    cursor: MultiBufferCursor<'a, Point>,
 438}
 439
 440pub struct MultiBufferChunks<'a> {
 441    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 442    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 443    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 444    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 445    buffer_chunk: Option<Chunk<'a>>,
 446    range: Range<usize>,
 447    excerpt_offset_range: Range<ExcerptOffset>,
 448    excerpt_chunks: Option<ExcerptChunks<'a>>,
 449    language_aware: bool,
 450}
 451
 452pub struct ReversedMultiBufferChunks<'a> {
 453    cursor: MultiBufferCursor<'a, usize>,
 454    current_chunks: Option<rope::Chunks<'a>>,
 455    start: usize,
 456    offset: usize,
 457}
 458
 459pub struct MultiBufferBytes<'a> {
 460    range: Range<usize>,
 461    cursor: MultiBufferCursor<'a, usize>,
 462    excerpt_bytes: Option<text::Bytes<'a>>,
 463    has_trailing_newline: bool,
 464    chunk: &'a [u8],
 465}
 466
 467pub struct ReversedMultiBufferBytes<'a> {
 468    range: Range<usize>,
 469    chunks: ReversedMultiBufferChunks<'a>,
 470    chunk: &'a [u8],
 471}
 472
 473#[derive(Clone)]
 474struct MultiBufferCursor<'a, D: TextDimension> {
 475    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 476    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 477    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 478    cached_region: Option<MultiBufferRegion<'a, D>>,
 479}
 480
 481#[derive(Clone)]
 482struct MultiBufferRegion<'a, D: TextDimension> {
 483    buffer: &'a BufferSnapshot,
 484    is_main_buffer: bool,
 485    diff_hunk_status: Option<DiffHunkStatus>,
 486    excerpt: &'a Excerpt,
 487    buffer_range: Range<D>,
 488    range: Range<D>,
 489    has_trailing_newline: bool,
 490}
 491
 492struct ExcerptChunks<'a> {
 493    excerpt_id: ExcerptId,
 494    content_chunks: BufferChunks<'a>,
 495    footer_height: usize,
 496}
 497
 498#[derive(Debug)]
 499struct BufferEdit {
 500    range: Range<usize>,
 501    new_text: Arc<str>,
 502    is_insertion: bool,
 503    original_start_column: u32,
 504    excerpt_id: ExcerptId,
 505}
 506
 507#[derive(Clone, Copy, Debug, PartialEq)]
 508enum DiffChangeKind {
 509    BufferEdited,
 510    DiffUpdated { base_changed: bool },
 511    ExpandOrCollapseHunks { expand: bool },
 512}
 513
 514#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 515pub enum ExpandExcerptDirection {
 516    Up,
 517    Down,
 518    UpAndDown,
 519}
 520
 521impl ExpandExcerptDirection {
 522    pub fn should_expand_up(&self) -> bool {
 523        match self {
 524            ExpandExcerptDirection::Up => true,
 525            ExpandExcerptDirection::Down => false,
 526            ExpandExcerptDirection::UpAndDown => true,
 527        }
 528    }
 529
 530    pub fn should_expand_down(&self) -> bool {
 531        match self {
 532            ExpandExcerptDirection::Up => false,
 533            ExpandExcerptDirection::Down => true,
 534            ExpandExcerptDirection::UpAndDown => true,
 535        }
 536    }
 537}
 538
 539#[derive(Clone, Debug, PartialEq)]
 540pub struct IndentGuide {
 541    pub buffer_id: BufferId,
 542    pub start_row: MultiBufferRow,
 543    pub end_row: MultiBufferRow,
 544    pub depth: u32,
 545    pub tab_size: u32,
 546    pub settings: IndentGuideSettings,
 547}
 548
 549impl IndentGuide {
 550    pub fn indent_level(&self) -> u32 {
 551        self.depth * self.tab_size
 552    }
 553}
 554
 555impl MultiBuffer {
 556    pub fn new(capability: Capability) -> Self {
 557        Self {
 558            snapshot: RefCell::new(MultiBufferSnapshot {
 559                show_headers: true,
 560                ..MultiBufferSnapshot::default()
 561            }),
 562            buffers: RefCell::default(),
 563            diffs: HashMap::default(),
 564            subscriptions: Topic::default(),
 565            singleton: false,
 566            capability,
 567            title: None,
 568            buffers_by_path: Default::default(),
 569            history: History {
 570                next_transaction_id: clock::Lamport::default(),
 571                undo_stack: Vec::new(),
 572                redo_stack: Vec::new(),
 573                transaction_depth: 0,
 574                group_interval: Duration::from_millis(300),
 575            },
 576        }
 577    }
 578
 579    pub fn without_headers(capability: Capability) -> Self {
 580        Self {
 581            snapshot: Default::default(),
 582            buffers: Default::default(),
 583            buffers_by_path: Default::default(),
 584            diffs: HashMap::default(),
 585            subscriptions: Default::default(),
 586            singleton: false,
 587            capability,
 588            history: History {
 589                next_transaction_id: Default::default(),
 590                undo_stack: Default::default(),
 591                redo_stack: Default::default(),
 592                transaction_depth: 0,
 593                group_interval: Duration::from_millis(300),
 594            },
 595            title: Default::default(),
 596        }
 597    }
 598
 599    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 600        let mut buffers = HashMap::default();
 601        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 602            buffers.insert(
 603                *buffer_id,
 604                BufferState {
 605                    buffer: buffer_state.buffer.clone(),
 606                    last_version: buffer_state.last_version.clone(),
 607                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 608                    excerpts: buffer_state.excerpts.clone(),
 609                    _subscriptions: [
 610                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 611                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 612                    ],
 613                },
 614            );
 615        }
 616        let mut diff_bases = HashMap::default();
 617        for (buffer_id, diff) in self.diffs.iter() {
 618            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 619        }
 620        Self {
 621            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 622            buffers: RefCell::new(buffers),
 623            buffers_by_path: Default::default(),
 624            diffs: diff_bases,
 625            subscriptions: Default::default(),
 626            singleton: self.singleton,
 627            capability: self.capability,
 628            history: self.history.clone(),
 629            title: self.title.clone(),
 630        }
 631    }
 632
 633    pub fn with_title(mut self, title: String) -> Self {
 634        self.title = Some(title);
 635        self
 636    }
 637
 638    pub fn read_only(&self) -> bool {
 639        self.capability == Capability::ReadOnly
 640    }
 641
 642    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 643        let mut this = Self::new(buffer.read(cx).capability());
 644        this.singleton = true;
 645        this.push_excerpts(
 646            buffer,
 647            [ExcerptRange {
 648                context: text::Anchor::MIN..text::Anchor::MAX,
 649                primary: None,
 650            }],
 651            cx,
 652        );
 653        this.snapshot.borrow_mut().singleton = true;
 654        this
 655    }
 656
 657    /// Returns an up-to-date snapshot of the MultiBuffer.
 658    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 659        self.sync(cx);
 660        self.snapshot.borrow().clone()
 661    }
 662
 663    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 664        self.sync(cx);
 665        self.snapshot.borrow()
 666    }
 667
 668    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 669        if self.singleton {
 670            return Some(
 671                self.buffers
 672                    .borrow()
 673                    .values()
 674                    .next()
 675                    .unwrap()
 676                    .buffer
 677                    .clone(),
 678            );
 679        } else {
 680            None
 681        }
 682    }
 683
 684    pub fn is_singleton(&self) -> bool {
 685        self.singleton
 686    }
 687
 688    pub fn subscribe(&mut self) -> Subscription {
 689        self.subscriptions.subscribe()
 690    }
 691
 692    pub fn is_dirty(&self, cx: &App) -> bool {
 693        self.read(cx).is_dirty()
 694    }
 695
 696    pub fn has_deleted_file(&self, cx: &App) -> bool {
 697        self.read(cx).has_deleted_file()
 698    }
 699
 700    pub fn has_conflict(&self, cx: &App) -> bool {
 701        self.read(cx).has_conflict()
 702    }
 703
 704    // The `is_empty` signature doesn't match what clippy expects
 705    #[allow(clippy::len_without_is_empty)]
 706    pub fn len(&self, cx: &App) -> usize {
 707        self.read(cx).len()
 708    }
 709
 710    pub fn is_empty(&self) -> bool {
 711        self.buffers.borrow().is_empty()
 712    }
 713
 714    pub fn symbols_containing<T: ToOffset>(
 715        &self,
 716        offset: T,
 717        theme: Option<&SyntaxTheme>,
 718        cx: &App,
 719    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 720        self.read(cx).symbols_containing(offset, theme)
 721    }
 722
 723    pub fn edit<I, S, T>(
 724        &self,
 725        edits: I,
 726        autoindent_mode: Option<AutoindentMode>,
 727        cx: &mut Context<Self>,
 728    ) where
 729        I: IntoIterator<Item = (Range<S>, T)>,
 730        S: ToOffset,
 731        T: Into<Arc<str>>,
 732    {
 733        let snapshot = self.read(cx);
 734        let edits = edits
 735            .into_iter()
 736            .map(|(range, new_text)| {
 737                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 738                if range.start > range.end {
 739                    mem::swap(&mut range.start, &mut range.end);
 740                }
 741                (range, new_text.into())
 742            })
 743            .collect::<Vec<_>>();
 744
 745        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 746
 747        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 748        fn edit_internal(
 749            this: &MultiBuffer,
 750            snapshot: Ref<MultiBufferSnapshot>,
 751            edits: Vec<(Range<usize>, Arc<str>)>,
 752            mut autoindent_mode: Option<AutoindentMode>,
 753            cx: &mut Context<MultiBuffer>,
 754        ) {
 755            if this.read_only() || this.buffers.borrow().is_empty() {
 756                return;
 757            }
 758
 759            let original_start_columns = match &mut autoindent_mode {
 760                Some(AutoindentMode::Block {
 761                    original_start_columns,
 762                }) => mem::take(original_start_columns),
 763                _ => Default::default(),
 764            };
 765
 766            let (buffer_edits, edited_excerpt_ids) =
 767                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_columns);
 768            drop(snapshot);
 769
 770            let mut buffer_ids = Vec::new();
 771            for (buffer_id, mut edits) in buffer_edits {
 772                buffer_ids.push(buffer_id);
 773                edits.sort_by_key(|edit| edit.range.start);
 774                this.buffers.borrow()[&buffer_id]
 775                    .buffer
 776                    .update(cx, |buffer, cx| {
 777                        let mut edits = edits.into_iter().peekable();
 778                        let mut insertions = Vec::new();
 779                        let mut original_indent_columns = Vec::new();
 780                        let mut deletions = Vec::new();
 781                        let empty_str: Arc<str> = Arc::default();
 782                        while let Some(BufferEdit {
 783                            mut range,
 784                            mut new_text,
 785                            mut is_insertion,
 786                            original_start_column: original_indent_column,
 787                            excerpt_id,
 788                        }) = edits.next()
 789                        {
 790                            while let Some(BufferEdit {
 791                                range: next_range,
 792                                is_insertion: next_is_insertion,
 793                                new_text: next_new_text,
 794                                excerpt_id: next_excerpt_id,
 795                                ..
 796                            }) = edits.peek()
 797                            {
 798                                if range.end >= next_range.start {
 799                                    range.end = cmp::max(next_range.end, range.end);
 800                                    is_insertion |= *next_is_insertion;
 801                                    if excerpt_id == *next_excerpt_id {
 802                                        new_text = format!("{new_text}{next_new_text}").into();
 803                                    }
 804                                    edits.next();
 805                                } else {
 806                                    break;
 807                                }
 808                            }
 809
 810                            if is_insertion {
 811                                original_indent_columns.push(original_indent_column);
 812                                insertions.push((
 813                                    buffer.anchor_before(range.start)
 814                                        ..buffer.anchor_before(range.end),
 815                                    new_text.clone(),
 816                                ));
 817                            } else if !range.is_empty() {
 818                                deletions.push((
 819                                    buffer.anchor_before(range.start)
 820                                        ..buffer.anchor_before(range.end),
 821                                    empty_str.clone(),
 822                                ));
 823                            }
 824                        }
 825
 826                        let deletion_autoindent_mode =
 827                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 828                                Some(AutoindentMode::Block {
 829                                    original_start_columns: Default::default(),
 830                                })
 831                            } else {
 832                                autoindent_mode.clone()
 833                            };
 834                        let insertion_autoindent_mode =
 835                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 836                                Some(AutoindentMode::Block {
 837                                    original_start_columns: original_indent_columns,
 838                                })
 839                            } else {
 840                                autoindent_mode.clone()
 841                            };
 842
 843                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 844                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 845                    })
 846            }
 847
 848            cx.emit(Event::ExcerptsEdited {
 849                excerpt_ids: edited_excerpt_ids,
 850                buffer_ids,
 851            });
 852        }
 853    }
 854
 855    fn convert_edits_to_buffer_edits(
 856        &self,
 857        edits: Vec<(Range<usize>, Arc<str>)>,
 858        snapshot: &MultiBufferSnapshot,
 859        original_start_columns: &[u32],
 860    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 861        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 862        let mut edited_excerpt_ids = Vec::new();
 863        let mut cursor = snapshot.cursor::<usize>();
 864        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 865            let original_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 866
 867            cursor.seek(&range.start);
 868            let mut start_region = cursor.region().expect("start offset out of bounds");
 869            if !start_region.is_main_buffer {
 870                cursor.next();
 871                if let Some(region) = cursor.region() {
 872                    start_region = region;
 873                } else {
 874                    continue;
 875                }
 876            }
 877
 878            if range.end < start_region.range.start {
 879                continue;
 880            }
 881
 882            if range.end > start_region.range.end {
 883                cursor.seek_forward(&range.end);
 884            }
 885            let mut end_region = cursor.region().expect("end offset out of bounds");
 886            if !end_region.is_main_buffer {
 887                cursor.prev();
 888                if let Some(region) = cursor.region() {
 889                    end_region = region;
 890                } else {
 891                    continue;
 892                }
 893            }
 894
 895            if range.start > end_region.range.end {
 896                continue;
 897            }
 898
 899            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 900            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 901            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 902                .min(start_region.buffer_range.end);
 903            let buffer_end =
 904                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 905
 906            if start_region.excerpt.id == end_region.excerpt.id {
 907                if start_region.is_main_buffer {
 908                    edited_excerpt_ids.push(start_region.excerpt.id);
 909                    buffer_edits
 910                        .entry(start_region.buffer.remote_id())
 911                        .or_default()
 912                        .push(BufferEdit {
 913                            range: buffer_start..buffer_end,
 914                            new_text,
 915                            is_insertion: true,
 916                            original_start_column,
 917                            excerpt_id: start_region.excerpt.id,
 918                        });
 919                }
 920            } else {
 921                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 922                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 923                if start_region.is_main_buffer {
 924                    edited_excerpt_ids.push(start_region.excerpt.id);
 925                    buffer_edits
 926                        .entry(start_region.buffer.remote_id())
 927                        .or_default()
 928                        .push(BufferEdit {
 929                            range: start_excerpt_range,
 930                            new_text: new_text.clone(),
 931                            is_insertion: true,
 932                            original_start_column,
 933                            excerpt_id: start_region.excerpt.id,
 934                        });
 935                }
 936                if end_region.is_main_buffer {
 937                    edited_excerpt_ids.push(end_region.excerpt.id);
 938                    buffer_edits
 939                        .entry(end_region.buffer.remote_id())
 940                        .or_default()
 941                        .push(BufferEdit {
 942                            range: end_excerpt_range,
 943                            new_text: new_text.clone(),
 944                            is_insertion: false,
 945                            original_start_column,
 946                            excerpt_id: end_region.excerpt.id,
 947                        });
 948                }
 949
 950                cursor.seek(&range.start);
 951                cursor.next_excerpt();
 952                while let Some(region) = cursor.region() {
 953                    if region.excerpt.id == end_region.excerpt.id {
 954                        break;
 955                    }
 956                    if region.is_main_buffer {
 957                        edited_excerpt_ids.push(region.excerpt.id);
 958                        buffer_edits
 959                            .entry(region.buffer.remote_id())
 960                            .or_default()
 961                            .push(BufferEdit {
 962                                range: region.buffer_range,
 963                                new_text: new_text.clone(),
 964                                is_insertion: false,
 965                                original_start_column,
 966                                excerpt_id: region.excerpt.id,
 967                            });
 968                    }
 969                    cursor.next_excerpt();
 970                }
 971            }
 972        }
 973        (buffer_edits, edited_excerpt_ids)
 974    }
 975
 976    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 977    where
 978        I: IntoIterator<Item = Range<S>>,
 979        S: ToOffset,
 980    {
 981        let snapshot = self.read(cx);
 982        let empty = Arc::<str>::from("");
 983        let edits = ranges
 984            .into_iter()
 985            .map(|range| {
 986                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 987                if range.start > range.end {
 988                    mem::swap(&mut range.start, &mut range.end);
 989                }
 990                (range, empty.clone())
 991            })
 992            .collect::<Vec<_>>();
 993
 994        return autoindent_ranges_internal(self, snapshot, edits, cx);
 995
 996        fn autoindent_ranges_internal(
 997            this: &MultiBuffer,
 998            snapshot: Ref<MultiBufferSnapshot>,
 999            edits: Vec<(Range<usize>, Arc<str>)>,
1000            cx: &mut Context<MultiBuffer>,
1001        ) {
1002            if this.read_only() || this.buffers.borrow().is_empty() {
1003                return;
1004            }
1005
1006            let (buffer_edits, edited_excerpt_ids) =
1007                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1008            drop(snapshot);
1009
1010            let mut buffer_ids = Vec::new();
1011            for (buffer_id, mut edits) in buffer_edits {
1012                buffer_ids.push(buffer_id);
1013                edits.sort_unstable_by_key(|edit| edit.range.start);
1014
1015                let mut ranges: Vec<Range<usize>> = Vec::new();
1016                for edit in edits {
1017                    if let Some(last_range) = ranges.last_mut() {
1018                        if edit.range.start <= last_range.end {
1019                            last_range.end = last_range.end.max(edit.range.end);
1020                            continue;
1021                        }
1022                    }
1023                    ranges.push(edit.range);
1024                }
1025
1026                this.buffers.borrow()[&buffer_id]
1027                    .buffer
1028                    .update(cx, |buffer, cx| {
1029                        buffer.autoindent_ranges(ranges, cx);
1030                    })
1031            }
1032
1033            cx.emit(Event::ExcerptsEdited {
1034                excerpt_ids: edited_excerpt_ids,
1035                buffer_ids,
1036            });
1037        }
1038    }
1039
1040    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1041    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1042    // Panics if the given position is invalid.
1043    pub fn insert_empty_line(
1044        &mut self,
1045        position: impl ToPoint,
1046        space_above: bool,
1047        space_below: bool,
1048        cx: &mut Context<Self>,
1049    ) -> Point {
1050        let multibuffer_point = position.to_point(&self.read(cx));
1051        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1052        self.start_transaction(cx);
1053        let empty_line_start = buffer.update(cx, |buffer, cx| {
1054            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1055        });
1056        self.end_transaction(cx);
1057        multibuffer_point + (empty_line_start - buffer_point)
1058    }
1059
1060    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1061        self.start_transaction_at(Instant::now(), cx)
1062    }
1063
1064    pub fn start_transaction_at(
1065        &mut self,
1066        now: Instant,
1067        cx: &mut Context<Self>,
1068    ) -> Option<TransactionId> {
1069        if let Some(buffer) = self.as_singleton() {
1070            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1071        }
1072
1073        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1074            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1075        }
1076        self.history.start_transaction(now)
1077    }
1078
1079    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1080        self.end_transaction_at(Instant::now(), cx)
1081    }
1082
1083    pub fn end_transaction_at(
1084        &mut self,
1085        now: Instant,
1086        cx: &mut Context<Self>,
1087    ) -> Option<TransactionId> {
1088        if let Some(buffer) = self.as_singleton() {
1089            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1090        }
1091
1092        let mut buffer_transactions = HashMap::default();
1093        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1094            if let Some(transaction_id) =
1095                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1096            {
1097                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1098            }
1099        }
1100
1101        if self.history.end_transaction(now, buffer_transactions) {
1102            let transaction_id = self.history.group().unwrap();
1103            Some(transaction_id)
1104        } else {
1105            None
1106        }
1107    }
1108
1109    pub fn edited_ranges_for_transaction<D>(
1110        &self,
1111        transaction_id: TransactionId,
1112        cx: &App,
1113    ) -> Vec<Range<D>>
1114    where
1115        D: TextDimension + Ord + Sub<D, Output = D>,
1116    {
1117        let Some(transaction) = self.history.transaction(transaction_id) else {
1118            return Vec::new();
1119        };
1120
1121        let mut ranges = Vec::new();
1122        let snapshot = self.read(cx);
1123        let buffers = self.buffers.borrow();
1124        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1125
1126        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1127            let Some(buffer_state) = buffers.get(buffer_id) else {
1128                continue;
1129            };
1130
1131            let buffer = buffer_state.buffer.read(cx);
1132            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1133                for excerpt_id in &buffer_state.excerpts {
1134                    cursor.seek(excerpt_id, Bias::Left, &());
1135                    if let Some(excerpt) = cursor.item() {
1136                        if excerpt.locator == *excerpt_id {
1137                            let excerpt_buffer_start =
1138                                excerpt.range.context.start.summary::<D>(buffer);
1139                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1140                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1141                            if excerpt_range.contains(&range.start)
1142                                && excerpt_range.contains(&range.end)
1143                            {
1144                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1145
1146                                let mut start = excerpt_start;
1147                                start.add_assign(&(range.start - excerpt_buffer_start));
1148                                let mut end = excerpt_start;
1149                                end.add_assign(&(range.end - excerpt_buffer_start));
1150
1151                                ranges.push(start..end);
1152                                break;
1153                            }
1154                        }
1155                    }
1156                }
1157            }
1158        }
1159
1160        ranges.sort_by_key(|range| range.start);
1161        ranges
1162    }
1163
1164    pub fn merge_transactions(
1165        &mut self,
1166        transaction: TransactionId,
1167        destination: TransactionId,
1168        cx: &mut Context<Self>,
1169    ) {
1170        if let Some(buffer) = self.as_singleton() {
1171            buffer.update(cx, |buffer, _| {
1172                buffer.merge_transactions(transaction, destination)
1173            });
1174        } else if let Some(transaction) = self.history.forget(transaction) {
1175            if let Some(destination) = self.history.transaction_mut(destination) {
1176                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1177                    if let Some(destination_buffer_transaction_id) =
1178                        destination.buffer_transactions.get(&buffer_id)
1179                    {
1180                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1181                            state.buffer.update(cx, |buffer, _| {
1182                                buffer.merge_transactions(
1183                                    buffer_transaction_id,
1184                                    *destination_buffer_transaction_id,
1185                                )
1186                            });
1187                        }
1188                    } else {
1189                        destination
1190                            .buffer_transactions
1191                            .insert(buffer_id, buffer_transaction_id);
1192                    }
1193                }
1194            }
1195        }
1196    }
1197
1198    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1199        self.history.finalize_last_transaction();
1200        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1201            buffer.update(cx, |buffer, _| {
1202                buffer.finalize_last_transaction();
1203            });
1204        }
1205    }
1206
1207    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1208    where
1209        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1210    {
1211        self.history
1212            .push_transaction(buffer_transactions, Instant::now(), cx);
1213        self.history.finalize_last_transaction();
1214    }
1215
1216    pub fn group_until_transaction(
1217        &mut self,
1218        transaction_id: TransactionId,
1219        cx: &mut Context<Self>,
1220    ) {
1221        if let Some(buffer) = self.as_singleton() {
1222            buffer.update(cx, |buffer, _| {
1223                buffer.group_until_transaction(transaction_id)
1224            });
1225        } else {
1226            self.history.group_until(transaction_id);
1227        }
1228    }
1229
1230    pub fn set_active_selections(
1231        &self,
1232        selections: &[Selection<Anchor>],
1233        line_mode: bool,
1234        cursor_shape: CursorShape,
1235        cx: &mut Context<Self>,
1236    ) {
1237        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1238            Default::default();
1239        let snapshot = self.read(cx);
1240        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1241        for selection in selections {
1242            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1243            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1244
1245            cursor.seek(&Some(start_locator), Bias::Left, &());
1246            while let Some(excerpt) = cursor.item() {
1247                if excerpt.locator > *end_locator {
1248                    break;
1249                }
1250
1251                let mut start = excerpt.range.context.start;
1252                let mut end = excerpt.range.context.end;
1253                if excerpt.id == selection.start.excerpt_id {
1254                    start = selection.start.text_anchor;
1255                }
1256                if excerpt.id == selection.end.excerpt_id {
1257                    end = selection.end.text_anchor;
1258                }
1259                selections_by_buffer
1260                    .entry(excerpt.buffer_id)
1261                    .or_default()
1262                    .push(Selection {
1263                        id: selection.id,
1264                        start,
1265                        end,
1266                        reversed: selection.reversed,
1267                        goal: selection.goal,
1268                    });
1269
1270                cursor.next(&());
1271            }
1272        }
1273
1274        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1275            if !selections_by_buffer.contains_key(buffer_id) {
1276                buffer_state
1277                    .buffer
1278                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1279            }
1280        }
1281
1282        for (buffer_id, mut selections) in selections_by_buffer {
1283            self.buffers.borrow()[&buffer_id]
1284                .buffer
1285                .update(cx, |buffer, cx| {
1286                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1287                    let mut selections = selections.into_iter().peekable();
1288                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1289                        let mut selection = selections.next()?;
1290                        while let Some(next_selection) = selections.peek() {
1291                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1292                                let next_selection = selections.next().unwrap();
1293                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1294                                    selection.end = next_selection.end;
1295                                }
1296                            } else {
1297                                break;
1298                            }
1299                        }
1300                        Some(selection)
1301                    }));
1302                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1303                });
1304        }
1305    }
1306
1307    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1308        for buffer in self.buffers.borrow().values() {
1309            buffer
1310                .buffer
1311                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1312        }
1313    }
1314
1315    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1316        let mut transaction_id = None;
1317        if let Some(buffer) = self.as_singleton() {
1318            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1319        } else {
1320            while let Some(transaction) = self.history.pop_undo() {
1321                let mut undone = false;
1322                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1323                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1324                        undone |= buffer.update(cx, |buffer, cx| {
1325                            let undo_to = *buffer_transaction_id;
1326                            if let Some(entry) = buffer.peek_undo_stack() {
1327                                *buffer_transaction_id = entry.transaction_id();
1328                            }
1329                            buffer.undo_to_transaction(undo_to, cx)
1330                        });
1331                    }
1332                }
1333
1334                if undone {
1335                    transaction_id = Some(transaction.id);
1336                    break;
1337                }
1338            }
1339        }
1340
1341        if let Some(transaction_id) = transaction_id {
1342            cx.emit(Event::TransactionUndone { transaction_id });
1343        }
1344
1345        transaction_id
1346    }
1347
1348    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1349        if let Some(buffer) = self.as_singleton() {
1350            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1351        }
1352
1353        while let Some(transaction) = self.history.pop_redo() {
1354            let mut redone = false;
1355            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1356                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1357                    redone |= buffer.update(cx, |buffer, cx| {
1358                        let redo_to = *buffer_transaction_id;
1359                        if let Some(entry) = buffer.peek_redo_stack() {
1360                            *buffer_transaction_id = entry.transaction_id();
1361                        }
1362                        buffer.redo_to_transaction(redo_to, cx)
1363                    });
1364                }
1365            }
1366
1367            if redone {
1368                return Some(transaction.id);
1369            }
1370        }
1371
1372        None
1373    }
1374
1375    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1376        if let Some(buffer) = self.as_singleton() {
1377            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1378        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1379            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1380                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1381                    buffer.update(cx, |buffer, cx| {
1382                        buffer.undo_transaction(*transaction_id, cx)
1383                    });
1384                }
1385            }
1386        }
1387    }
1388
1389    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1390        if let Some(buffer) = self.as_singleton() {
1391            buffer.update(cx, |buffer, _| {
1392                buffer.forget_transaction(transaction_id);
1393            });
1394        } else if let Some(transaction) = self.history.forget(transaction_id) {
1395            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1396                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1397                    state.buffer.update(cx, |buffer, _| {
1398                        buffer.forget_transaction(buffer_transaction_id);
1399                    });
1400                }
1401            }
1402        }
1403    }
1404
1405    pub fn push_excerpts<O>(
1406        &mut self,
1407        buffer: Entity<Buffer>,
1408        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1409        cx: &mut Context<Self>,
1410    ) -> Vec<ExcerptId>
1411    where
1412        O: text::ToOffset,
1413    {
1414        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1415    }
1416
1417    pub fn push_excerpts_with_context_lines<O>(
1418        &mut self,
1419        buffer: Entity<Buffer>,
1420        ranges: Vec<Range<O>>,
1421        context_line_count: u32,
1422        cx: &mut Context<Self>,
1423    ) -> Vec<Range<Anchor>>
1424    where
1425        O: text::ToPoint + text::ToOffset,
1426    {
1427        let buffer_id = buffer.read(cx).remote_id();
1428        let buffer_snapshot = buffer.read(cx).snapshot();
1429        let (excerpt_ranges, range_counts) =
1430            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1431
1432        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1433
1434        let mut anchor_ranges = Vec::new();
1435        let mut ranges = ranges.into_iter();
1436        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1437            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1438                let start = Anchor {
1439                    buffer_id: Some(buffer_id),
1440                    excerpt_id,
1441                    text_anchor: buffer_snapshot.anchor_after(range.start),
1442                    diff_base_anchor: None,
1443                };
1444                let end = Anchor {
1445                    buffer_id: Some(buffer_id),
1446                    excerpt_id,
1447                    text_anchor: buffer_snapshot.anchor_after(range.end),
1448                    diff_base_anchor: None,
1449                };
1450                start..end
1451            }))
1452        }
1453        anchor_ranges
1454    }
1455
1456    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1457        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1458        let snapshot = self.snapshot(cx);
1459        let excerpt = snapshot.excerpt(*excerpt_id)?;
1460        Some(Anchor::in_buffer(
1461            *excerpt_id,
1462            excerpt.buffer_id,
1463            excerpt.range.context.start,
1464        ))
1465    }
1466
1467    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1468        self.buffers_by_path.keys()
1469    }
1470
1471    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1472    pub fn set_excerpts_for_path(
1473        &mut self,
1474        path: PathKey,
1475        buffer: Entity<Buffer>,
1476        ranges: Vec<Range<Point>>,
1477        context_line_count: u32,
1478        cx: &mut Context<Self>,
1479    ) -> bool {
1480        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1481
1482        let mut insert_after = self
1483            .buffers_by_path
1484            .range(..path.clone())
1485            .next_back()
1486            .map(|(_, value)| *value.last().unwrap())
1487            .unwrap_or(ExcerptId::min());
1488        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1489
1490        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1491
1492        let mut new_iter = new.into_iter().peekable();
1493        let mut existing_iter = existing.into_iter().peekable();
1494
1495        let mut new_excerpt_ids = Vec::new();
1496        let mut to_remove = Vec::new();
1497        let mut to_insert = Vec::new();
1498        let mut added_a_new_excerpt = false;
1499        let snapshot = self.snapshot(cx);
1500
1501        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1502        excerpts_cursor.next(&());
1503
1504        loop {
1505            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1506                (Some(new), Some(existing)) => (new, existing),
1507                (None, None) => break,
1508                (None, Some(_)) => {
1509                    to_remove.push(existing_iter.next().unwrap());
1510                    continue;
1511                }
1512                (Some(_), None) => {
1513                    added_a_new_excerpt = true;
1514                    to_insert.push(new_iter.next().unwrap());
1515                    continue;
1516                }
1517            };
1518            let locator = snapshot.excerpt_locator_for_id(*existing);
1519            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1520            let existing_excerpt = excerpts_cursor.item().unwrap();
1521            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1522                to_remove.push(existing_iter.next().unwrap());
1523                to_insert.push(new_iter.next().unwrap());
1524                continue;
1525            }
1526
1527            let existing_start = existing_excerpt
1528                .range
1529                .context
1530                .start
1531                .to_point(&buffer_snapshot);
1532            let existing_end = existing_excerpt
1533                .range
1534                .context
1535                .end
1536                .to_point(&buffer_snapshot);
1537
1538            if existing_end < new.context.start {
1539                to_remove.push(existing_iter.next().unwrap());
1540                continue;
1541            } else if existing_start > new.context.end {
1542                to_insert.push(new_iter.next().unwrap());
1543                continue;
1544            }
1545
1546            // maybe merge overlapping excerpts?
1547            // it's hard to distinguish between a manually expanded excerpt, and one that
1548            // got smaller because of a missing diff.
1549            if existing_start == new.context.start && existing_end == new.context.end {
1550                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1551                    insert_after,
1552                    buffer.clone(),
1553                    mem::take(&mut to_insert),
1554                    cx,
1555                ));
1556                insert_after = existing_iter.next().unwrap();
1557                new_excerpt_ids.push(insert_after);
1558                new_iter.next();
1559            } else {
1560                to_remove.push(existing_iter.next().unwrap());
1561                to_insert.push(new_iter.next().unwrap());
1562            }
1563        }
1564
1565        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1566            insert_after,
1567            buffer,
1568            to_insert,
1569            cx,
1570        ));
1571        self.remove_excerpts(to_remove, cx);
1572        if new_excerpt_ids.is_empty() {
1573            self.buffers_by_path.remove(&path);
1574        } else {
1575            self.buffers_by_path.insert(path, new_excerpt_ids);
1576        }
1577
1578        added_a_new_excerpt
1579    }
1580
1581    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1582        self.buffers_by_path.keys().cloned()
1583    }
1584
1585    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1586        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1587            self.remove_excerpts(to_remove, cx)
1588        }
1589    }
1590
1591    pub fn push_multiple_excerpts_with_context_lines(
1592        &self,
1593        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1594        context_line_count: u32,
1595        cx: &mut Context<Self>,
1596    ) -> Task<Vec<Range<Anchor>>> {
1597        use futures::StreamExt;
1598
1599        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1600
1601        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1602
1603        for (buffer, ranges) in buffers_with_ranges {
1604            let (buffer_id, buffer_snapshot) =
1605                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1606
1607            buffer_ids.push(buffer_id);
1608
1609            cx.background_spawn({
1610                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1611
1612                async move {
1613                    let (excerpt_ranges, counts) =
1614                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1615                    excerpt_ranges_tx
1616                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1617                        .await
1618                        .ok();
1619                }
1620            })
1621            .detach()
1622        }
1623
1624        cx.spawn(move |this, mut cx| async move {
1625            let mut results_by_buffer_id = HashMap::default();
1626            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1627                excerpt_ranges_rx.next().await
1628            {
1629                results_by_buffer_id
1630                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1631            }
1632
1633            let mut multi_buffer_ranges = Vec::default();
1634            'outer: for buffer_id in buffer_ids {
1635                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1636                    results_by_buffer_id.remove(&buffer_id)
1637                else {
1638                    continue;
1639                };
1640
1641                let mut ranges = ranges.into_iter();
1642                let mut range_counts = range_counts.into_iter();
1643                for excerpt_ranges in excerpt_ranges.chunks(100) {
1644                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1645                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1646                    }) {
1647                        Ok(excerpt_ids) => excerpt_ids,
1648                        Err(_) => continue 'outer,
1649                    };
1650
1651                    for (excerpt_id, range_count) in
1652                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1653                    {
1654                        for range in ranges.by_ref().take(range_count) {
1655                            let start = Anchor {
1656                                buffer_id: Some(buffer_id),
1657                                excerpt_id,
1658                                text_anchor: range.start,
1659                                diff_base_anchor: None,
1660                            };
1661                            let end = Anchor {
1662                                buffer_id: Some(buffer_id),
1663                                excerpt_id,
1664                                text_anchor: range.end,
1665                                diff_base_anchor: None,
1666                            };
1667                            multi_buffer_ranges.push(start..end);
1668                        }
1669                    }
1670                }
1671            }
1672
1673            multi_buffer_ranges
1674        })
1675    }
1676
1677    pub fn insert_excerpts_after<O>(
1678        &mut self,
1679        prev_excerpt_id: ExcerptId,
1680        buffer: Entity<Buffer>,
1681        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1682        cx: &mut Context<Self>,
1683    ) -> Vec<ExcerptId>
1684    where
1685        O: text::ToOffset,
1686    {
1687        let mut ids = Vec::new();
1688        let mut next_excerpt_id =
1689            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1690                last_entry.id.0 + 1
1691            } else {
1692                1
1693            };
1694        self.insert_excerpts_with_ids_after(
1695            prev_excerpt_id,
1696            buffer,
1697            ranges.into_iter().map(|range| {
1698                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1699                ids.push(id);
1700                (id, range)
1701            }),
1702            cx,
1703        );
1704        ids
1705    }
1706
1707    pub fn insert_excerpts_with_ids_after<O>(
1708        &mut self,
1709        prev_excerpt_id: ExcerptId,
1710        buffer: Entity<Buffer>,
1711        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1712        cx: &mut Context<Self>,
1713    ) where
1714        O: text::ToOffset,
1715    {
1716        assert_eq!(self.history.transaction_depth, 0);
1717        let mut ranges = ranges.into_iter().peekable();
1718        if ranges.peek().is_none() {
1719            return Default::default();
1720        }
1721
1722        self.sync(cx);
1723
1724        let buffer_id = buffer.read(cx).remote_id();
1725        let buffer_snapshot = buffer.read(cx).snapshot();
1726
1727        let mut buffers = self.buffers.borrow_mut();
1728        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1729            last_version: buffer_snapshot.version().clone(),
1730            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1731            excerpts: Default::default(),
1732            _subscriptions: [
1733                cx.observe(&buffer, |_, _, cx| cx.notify()),
1734                cx.subscribe(&buffer, Self::on_buffer_event),
1735            ],
1736            buffer: buffer.clone(),
1737        });
1738
1739        let mut snapshot = self.snapshot.borrow_mut();
1740
1741        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1742        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1743        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1744        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1745        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1746
1747        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1748        new_excerpts.update_last(
1749            |excerpt| {
1750                excerpt.has_trailing_newline = true;
1751            },
1752            &(),
1753        );
1754
1755        let next_locator = if let Some(excerpt) = cursor.item() {
1756            excerpt.locator.clone()
1757        } else {
1758            Locator::max()
1759        };
1760
1761        let mut excerpts = Vec::new();
1762        while let Some((id, range)) = ranges.next() {
1763            let locator = Locator::between(&prev_locator, &next_locator);
1764            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1765                buffer_state.excerpts.insert(ix, locator.clone());
1766            }
1767            let range = ExcerptRange {
1768                context: buffer_snapshot.anchor_before(&range.context.start)
1769                    ..buffer_snapshot.anchor_after(&range.context.end),
1770                primary: range.primary.map(|primary| {
1771                    buffer_snapshot.anchor_before(&primary.start)
1772                        ..buffer_snapshot.anchor_after(&primary.end)
1773                }),
1774            };
1775            excerpts.push((id, range.clone()));
1776            let excerpt = Excerpt::new(
1777                id,
1778                locator.clone(),
1779                buffer_id,
1780                buffer_snapshot.clone(),
1781                range,
1782                ranges.peek().is_some() || cursor.item().is_some(),
1783            );
1784            new_excerpts.push(excerpt, &());
1785            prev_locator = locator.clone();
1786
1787            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1788                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1789            }
1790            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1791        }
1792
1793        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1794
1795        let suffix = cursor.suffix(&());
1796        let changed_trailing_excerpt = suffix.is_empty();
1797        new_excerpts.append(suffix, &());
1798        drop(cursor);
1799        snapshot.excerpts = new_excerpts;
1800        snapshot.excerpt_ids = new_excerpt_ids;
1801        if changed_trailing_excerpt {
1802            snapshot.trailing_excerpt_update_count += 1;
1803        }
1804
1805        self.sync_diff_transforms(
1806            &mut snapshot,
1807            vec![Edit {
1808                old: edit_start..edit_start,
1809                new: edit_start..edit_end,
1810            }],
1811            DiffChangeKind::BufferEdited,
1812        );
1813        cx.emit(Event::Edited {
1814            singleton_buffer_edited: false,
1815            edited_buffer: None,
1816        });
1817        cx.emit(Event::ExcerptsAdded {
1818            buffer,
1819            predecessor: prev_excerpt_id,
1820            excerpts,
1821        });
1822        cx.notify();
1823    }
1824
1825    pub fn clear(&mut self, cx: &mut Context<Self>) {
1826        self.sync(cx);
1827        let ids = self.excerpt_ids();
1828        self.buffers.borrow_mut().clear();
1829        let mut snapshot = self.snapshot.borrow_mut();
1830        let start = ExcerptOffset::new(0);
1831        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1832        snapshot.excerpts = Default::default();
1833        snapshot.trailing_excerpt_update_count += 1;
1834        snapshot.is_dirty = false;
1835        snapshot.has_deleted_file = false;
1836        snapshot.has_conflict = false;
1837
1838        self.sync_diff_transforms(
1839            &mut snapshot,
1840            vec![Edit {
1841                old: start..prev_len,
1842                new: start..start,
1843            }],
1844            DiffChangeKind::BufferEdited,
1845        );
1846        cx.emit(Event::Edited {
1847            singleton_buffer_edited: false,
1848            edited_buffer: None,
1849        });
1850        cx.emit(Event::ExcerptsRemoved { ids });
1851        cx.notify();
1852    }
1853
1854    pub fn excerpts_for_buffer(
1855        &self,
1856        buffer_id: BufferId,
1857        cx: &App,
1858    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1859        let mut excerpts = Vec::new();
1860        let snapshot = self.read(cx);
1861        let buffers = self.buffers.borrow();
1862        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1863        for locator in buffers
1864            .get(&buffer_id)
1865            .map(|state| &state.excerpts)
1866            .into_iter()
1867            .flatten()
1868        {
1869            cursor.seek_forward(&Some(locator), Bias::Left, &());
1870            if let Some(excerpt) = cursor.item() {
1871                if excerpt.locator == *locator {
1872                    excerpts.push((excerpt.id, excerpt.range.clone()));
1873                }
1874            }
1875        }
1876
1877        excerpts
1878    }
1879
1880    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1881        let snapshot = self.read(cx);
1882        let buffers = self.buffers.borrow();
1883        let mut excerpts = snapshot
1884            .excerpts
1885            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1886        let mut diff_transforms = snapshot
1887            .diff_transforms
1888            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1889        diff_transforms.next(&());
1890        let locators = buffers
1891            .get(&buffer_id)
1892            .into_iter()
1893            .flat_map(|state| &state.excerpts);
1894        let mut result = Vec::new();
1895        for locator in locators {
1896            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1897            if let Some(excerpt) = excerpts.item() {
1898                if excerpt.locator == *locator {
1899                    let excerpt_start = excerpts.start().1.clone();
1900                    let excerpt_end =
1901                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1902
1903                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1904                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1905                    let start = diff_transforms.start().1 .0 + overshoot;
1906
1907                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1908                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1909                    let end = diff_transforms.start().1 .0 + overshoot;
1910
1911                    result.push(start..end)
1912                }
1913            }
1914        }
1915        result
1916    }
1917
1918    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1919        self.snapshot
1920            .borrow()
1921            .excerpts
1922            .iter()
1923            .map(|entry| entry.buffer_id)
1924            .collect()
1925    }
1926
1927    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1928        self.snapshot
1929            .borrow()
1930            .excerpts
1931            .iter()
1932            .map(|entry| entry.id)
1933            .collect()
1934    }
1935
1936    pub fn excerpt_containing(
1937        &self,
1938        position: impl ToOffset,
1939        cx: &App,
1940    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1941        let snapshot = self.read(cx);
1942        let offset = position.to_offset(&snapshot);
1943
1944        let mut cursor = snapshot.cursor::<usize>();
1945        cursor.seek(&offset);
1946        cursor
1947            .excerpt()
1948            .or_else(|| snapshot.excerpts.last())
1949            .map(|excerpt| {
1950                (
1951                    excerpt.id,
1952                    self.buffers
1953                        .borrow()
1954                        .get(&excerpt.buffer_id)
1955                        .unwrap()
1956                        .buffer
1957                        .clone(),
1958                    excerpt.range.context.clone(),
1959                )
1960            })
1961    }
1962
1963    // If point is at the end of the buffer, the last excerpt is returned
1964    pub fn point_to_buffer_offset<T: ToOffset>(
1965        &self,
1966        point: T,
1967        cx: &App,
1968    ) -> Option<(Entity<Buffer>, usize)> {
1969        let snapshot = self.read(cx);
1970        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1971        Some((
1972            self.buffers
1973                .borrow()
1974                .get(&buffer.remote_id())?
1975                .buffer
1976                .clone(),
1977            offset,
1978        ))
1979    }
1980
1981    // If point is at the end of the buffer, the last excerpt is returned
1982    pub fn point_to_buffer_point<T: ToPoint>(
1983        &self,
1984        point: T,
1985        cx: &App,
1986    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1987        let snapshot = self.read(cx);
1988        let point = point.to_point(&snapshot);
1989        let mut cursor = snapshot.cursor::<Point>();
1990        cursor.seek(&point);
1991
1992        cursor.region().and_then(|region| {
1993            if !region.is_main_buffer {
1994                return None;
1995            }
1996
1997            let overshoot = point - region.range.start;
1998            let buffer_point = region.buffer_range.start + overshoot;
1999            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
2000                .buffer
2001                .clone();
2002            Some((buffer, buffer_point, region.excerpt.id))
2003        })
2004    }
2005
2006    pub fn buffer_point_to_anchor(
2007        &self,
2008        buffer: &Entity<Buffer>,
2009        point: Point,
2010        cx: &App,
2011    ) -> Option<Anchor> {
2012        let mut found = None;
2013        let snapshot = buffer.read(cx).snapshot();
2014        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2015            let start = range.context.start.to_point(&snapshot);
2016            let end = range.context.end.to_point(&snapshot);
2017            if start <= point && point < end {
2018                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2019                break;
2020            }
2021            if point < start {
2022                found = Some((start, excerpt_id));
2023            }
2024            if point > end {
2025                found = Some((end, excerpt_id));
2026            }
2027        }
2028
2029        found.map(|(point, excerpt_id)| {
2030            let text_anchor = snapshot.anchor_after(point);
2031            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2032        })
2033    }
2034
2035    pub fn remove_excerpts(
2036        &mut self,
2037        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2038        cx: &mut Context<Self>,
2039    ) {
2040        self.sync(cx);
2041        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2042        if ids.is_empty() {
2043            return;
2044        }
2045
2046        let mut buffers = self.buffers.borrow_mut();
2047        let mut snapshot = self.snapshot.borrow_mut();
2048        let mut new_excerpts = SumTree::default();
2049        let mut cursor = snapshot
2050            .excerpts
2051            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2052        let mut edits = Vec::new();
2053        let mut excerpt_ids = ids.iter().copied().peekable();
2054        let mut removed_buffer_ids = Vec::new();
2055
2056        while let Some(excerpt_id) = excerpt_ids.next() {
2057            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2058            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2059            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2060
2061            if let Some(mut excerpt) = cursor.item() {
2062                if excerpt.id != excerpt_id {
2063                    continue;
2064                }
2065                let mut old_start = cursor.start().1;
2066
2067                // Skip over the removed excerpt.
2068                'remove_excerpts: loop {
2069                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2070                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2071                        if buffer_state.excerpts.is_empty() {
2072                            log::debug!(
2073                                "removing buffer and diff for buffer {}",
2074                                excerpt.buffer_id
2075                            );
2076                            buffers.remove(&excerpt.buffer_id);
2077                            removed_buffer_ids.push(excerpt.buffer_id);
2078                        }
2079                    }
2080                    cursor.next(&());
2081
2082                    // Skip over any subsequent excerpts that are also removed.
2083                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2084                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2085                        if let Some(next_excerpt) = cursor.item() {
2086                            if next_excerpt.locator == *next_locator {
2087                                excerpt_ids.next();
2088                                excerpt = next_excerpt;
2089                                continue 'remove_excerpts;
2090                            }
2091                        }
2092                    }
2093
2094                    break;
2095                }
2096
2097                // When removing the last excerpt, remove the trailing newline from
2098                // the previous excerpt.
2099                if cursor.item().is_none() && old_start.value > 0 {
2100                    old_start.value -= 1;
2101                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2102                }
2103
2104                // Push an edit for the removal of this run of excerpts.
2105                let old_end = cursor.start().1;
2106                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2107                edits.push(Edit {
2108                    old: old_start..old_end,
2109                    new: new_start..new_start,
2110                });
2111            }
2112        }
2113        let suffix = cursor.suffix(&());
2114        let changed_trailing_excerpt = suffix.is_empty();
2115        new_excerpts.append(suffix, &());
2116        drop(cursor);
2117        snapshot.excerpts = new_excerpts;
2118        for buffer_id in removed_buffer_ids {
2119            self.diffs.remove(&buffer_id);
2120            snapshot.diffs.remove(&buffer_id);
2121        }
2122
2123        if changed_trailing_excerpt {
2124            snapshot.trailing_excerpt_update_count += 1;
2125        }
2126
2127        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2128        cx.emit(Event::Edited {
2129            singleton_buffer_edited: false,
2130            edited_buffer: None,
2131        });
2132        cx.emit(Event::ExcerptsRemoved { ids });
2133        cx.notify();
2134    }
2135
2136    pub fn wait_for_anchors<'a>(
2137        &self,
2138        anchors: impl 'a + Iterator<Item = Anchor>,
2139        cx: &mut Context<Self>,
2140    ) -> impl 'static + Future<Output = Result<()>> {
2141        let borrow = self.buffers.borrow();
2142        let mut error = None;
2143        let mut futures = Vec::new();
2144        for anchor in anchors {
2145            if let Some(buffer_id) = anchor.buffer_id {
2146                if let Some(buffer) = borrow.get(&buffer_id) {
2147                    buffer.buffer.update(cx, |buffer, _| {
2148                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2149                    });
2150                } else {
2151                    error = Some(anyhow!(
2152                        "buffer {buffer_id} is not part of this multi-buffer"
2153                    ));
2154                    break;
2155                }
2156            }
2157        }
2158        async move {
2159            if let Some(error) = error {
2160                Err(error)?;
2161            }
2162            for future in futures {
2163                future.await?;
2164            }
2165            Ok(())
2166        }
2167    }
2168
2169    pub fn text_anchor_for_position<T: ToOffset>(
2170        &self,
2171        position: T,
2172        cx: &App,
2173    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2174        let snapshot = self.read(cx);
2175        let anchor = snapshot.anchor_before(position);
2176        let buffer = self
2177            .buffers
2178            .borrow()
2179            .get(&anchor.buffer_id?)?
2180            .buffer
2181            .clone();
2182        Some((buffer, anchor.text_anchor))
2183    }
2184
2185    fn on_buffer_event(
2186        &mut self,
2187        buffer: Entity<Buffer>,
2188        event: &language::BufferEvent,
2189        cx: &mut Context<Self>,
2190    ) {
2191        cx.emit(match event {
2192            language::BufferEvent::Edited => Event::Edited {
2193                singleton_buffer_edited: true,
2194                edited_buffer: Some(buffer.clone()),
2195            },
2196            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2197            language::BufferEvent::Saved => Event::Saved,
2198            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2199            language::BufferEvent::Reloaded => Event::Reloaded,
2200            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2201            language::BufferEvent::LanguageChanged => {
2202                Event::LanguageChanged(buffer.read(cx).remote_id())
2203            }
2204            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2205            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2206            language::BufferEvent::Closed => Event::Closed,
2207            language::BufferEvent::Discarded => Event::Discarded,
2208            language::BufferEvent::CapabilityChanged => {
2209                self.capability = buffer.read(cx).capability();
2210                Event::CapabilityChanged
2211            }
2212            language::BufferEvent::Operation { .. } => return,
2213        });
2214    }
2215
2216    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2217        self.sync(cx);
2218        let mut snapshot = self.snapshot.borrow_mut();
2219        let diff = diff.read(cx);
2220        let buffer_id = diff.buffer_id;
2221        let diff = diff.snapshot(cx);
2222        snapshot.diffs.insert(buffer_id, diff);
2223    }
2224
2225    fn buffer_diff_changed(
2226        &mut self,
2227        diff: Entity<BufferDiff>,
2228        range: Range<text::Anchor>,
2229        cx: &mut Context<Self>,
2230    ) {
2231        self.sync(cx);
2232
2233        let diff = diff.read(cx);
2234        let buffer_id = diff.buffer_id;
2235        let buffers = self.buffers.borrow();
2236        let Some(buffer_state) = buffers.get(&buffer_id) else {
2237            return;
2238        };
2239
2240        let buffer = buffer_state.buffer.read(cx);
2241        let diff_change_range = range.to_offset(buffer);
2242
2243        let new_diff = diff.snapshot(cx);
2244        let mut snapshot = self.snapshot.borrow_mut();
2245        let base_text_changed = snapshot
2246            .diffs
2247            .get(&buffer_id)
2248            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2249
2250        snapshot.diffs.insert(buffer_id, new_diff);
2251
2252        let mut excerpt_edits = Vec::new();
2253        for locator in &buffer_state.excerpts {
2254            let mut cursor = snapshot
2255                .excerpts
2256                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2257            cursor.seek_forward(&Some(locator), Bias::Left, &());
2258            if let Some(excerpt) = cursor.item() {
2259                if excerpt.locator == *locator {
2260                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2261                    if diff_change_range.end < excerpt_buffer_range.start
2262                        || diff_change_range.start > excerpt_buffer_range.end
2263                    {
2264                        continue;
2265                    }
2266                    let excerpt_start = cursor.start().1;
2267                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2268                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2269                        diff_change_range
2270                            .start
2271                            .saturating_sub(excerpt_buffer_range.start),
2272                    );
2273                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2274                        diff_change_range
2275                            .end
2276                            .saturating_sub(excerpt_buffer_range.start),
2277                    );
2278                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2279                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2280                    excerpt_edits.push(Edit {
2281                        old: edit_start..edit_end,
2282                        new: edit_start..edit_end,
2283                    });
2284                }
2285            }
2286        }
2287
2288        self.sync_diff_transforms(
2289            &mut snapshot,
2290            excerpt_edits,
2291            DiffChangeKind::DiffUpdated {
2292                base_changed: base_text_changed,
2293            },
2294        );
2295        cx.emit(Event::Edited {
2296            singleton_buffer_edited: false,
2297            edited_buffer: None,
2298        });
2299    }
2300
2301    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2302        self.buffers
2303            .borrow()
2304            .values()
2305            .map(|state| state.buffer.clone())
2306            .collect()
2307    }
2308
2309    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2310        self.buffers
2311            .borrow()
2312            .get(&buffer_id)
2313            .map(|state| state.buffer.clone())
2314    }
2315
2316    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2317        self.point_to_buffer_offset(point, cx)
2318            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2319    }
2320
2321    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2322        let mut language = None;
2323        let mut file = None;
2324        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2325            let buffer = buffer.read(cx);
2326            language = buffer.language_at(offset);
2327            file = buffer.file();
2328        }
2329        language_settings(language.map(|l| l.name()), file, cx)
2330    }
2331
2332    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2333        self.buffers
2334            .borrow()
2335            .values()
2336            .for_each(|state| f(&state.buffer))
2337    }
2338
2339    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2340        if let Some(title) = self.title.as_ref() {
2341            return title.into();
2342        }
2343
2344        if let Some(buffer) = self.as_singleton() {
2345            if let Some(file) = buffer.read(cx).file() {
2346                return file.file_name(cx).to_string_lossy();
2347            }
2348        }
2349
2350        "untitled".into()
2351    }
2352
2353    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2354        self.title = Some(title);
2355        cx.notify();
2356    }
2357
2358    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2359    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2360        for buffer_state in self.buffers.borrow().values() {
2361            buffer_state
2362                .buffer
2363                .update(cx, |buffer, _cx| buffer.refresh_preview());
2364        }
2365    }
2366
2367    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2368    pub fn preserve_preview(&self, cx: &App) -> bool {
2369        self.buffers
2370            .borrow()
2371            .values()
2372            .all(|state| state.buffer.read(cx).preserve_preview())
2373    }
2374
2375    #[cfg(any(test, feature = "test-support"))]
2376    pub fn is_parsing(&self, cx: &App) -> bool {
2377        self.as_singleton().unwrap().read(cx).is_parsing()
2378    }
2379
2380    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2381        let buffer_id = diff.read(cx).buffer_id;
2382        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2383        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2384    }
2385
2386    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2387        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2388    }
2389
2390    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2391        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2392    }
2393
2394    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2395        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2396    }
2397
2398    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2399        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2400        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2401    }
2402
2403    pub fn all_diff_hunks_expanded(&self) -> bool {
2404        self.snapshot.borrow().all_diff_hunks_expanded
2405    }
2406
2407    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2408        self.read(cx)
2409            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2410            .nth(1)
2411            .is_some()
2412    }
2413
2414    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2415        let snapshot = self.read(cx);
2416        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2417        let offset_range = range.to_offset(&snapshot);
2418        cursor.seek(&offset_range.start, Bias::Left, &());
2419        while let Some(item) = cursor.item() {
2420            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2421                break;
2422            }
2423            if item.hunk_info().is_some() {
2424                return true;
2425            }
2426            cursor.next(&());
2427        }
2428        false
2429    }
2430
2431    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2432        let snapshot = self.read(cx);
2433        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2434        for range in ranges {
2435            let range = range.to_point(&snapshot);
2436            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2437            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2438            let start = start.saturating_sub(1);
2439            let end = snapshot.len().min(end + 1);
2440            cursor.seek(&start, Bias::Right, &());
2441            while let Some(item) = cursor.item() {
2442                if *cursor.start() >= end {
2443                    break;
2444                }
2445                if item.hunk_info().is_some() {
2446                    return true;
2447                }
2448                cursor.next(&());
2449            }
2450        }
2451        false
2452    }
2453
2454    pub fn expand_or_collapse_diff_hunks_inner(
2455        &mut self,
2456        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2457        expand: bool,
2458        cx: &mut Context<Self>,
2459    ) {
2460        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2461            return;
2462        }
2463        self.sync(cx);
2464        let mut snapshot = self.snapshot.borrow_mut();
2465        let mut excerpt_edits = Vec::new();
2466        for (range, end_excerpt_id) in ranges {
2467            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2468                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2469                    continue;
2470                }
2471                let start = Anchor::in_buffer(
2472                    diff_hunk.excerpt_id,
2473                    diff_hunk.buffer_id,
2474                    diff_hunk.buffer_range.start,
2475                );
2476                let end = Anchor::in_buffer(
2477                    diff_hunk.excerpt_id,
2478                    diff_hunk.buffer_id,
2479                    diff_hunk.buffer_range.end,
2480                );
2481                let start = snapshot.excerpt_offset_for_anchor(&start);
2482                let end = snapshot.excerpt_offset_for_anchor(&end);
2483                excerpt_edits.push(text::Edit {
2484                    old: start..end,
2485                    new: start..end,
2486                });
2487            }
2488        }
2489
2490        self.sync_diff_transforms(
2491            &mut snapshot,
2492            excerpt_edits,
2493            DiffChangeKind::ExpandOrCollapseHunks { expand },
2494        );
2495        cx.emit(Event::DiffHunksToggled);
2496        cx.emit(Event::Edited {
2497            singleton_buffer_edited: false,
2498            edited_buffer: None,
2499        });
2500    }
2501
2502    pub fn expand_or_collapse_diff_hunks(
2503        &mut self,
2504        ranges: Vec<Range<Anchor>>,
2505        expand: bool,
2506        cx: &mut Context<Self>,
2507    ) {
2508        let snapshot = self.snapshot.borrow().clone();
2509        let ranges = ranges.iter().map(move |range| {
2510            let end_excerpt_id = range.end.excerpt_id;
2511            let range = range.to_point(&snapshot);
2512            let mut peek_end = range.end;
2513            if range.end.row < snapshot.max_row().0 {
2514                peek_end = Point::new(range.end.row + 1, 0);
2515            };
2516            (range.start..peek_end, end_excerpt_id)
2517        });
2518        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2519    }
2520
2521    pub fn resize_excerpt(
2522        &mut self,
2523        id: ExcerptId,
2524        range: Range<text::Anchor>,
2525        cx: &mut Context<Self>,
2526    ) {
2527        self.sync(cx);
2528
2529        let mut snapshot = self.snapshot.borrow_mut();
2530        let locator = snapshot.excerpt_locator_for_id(id);
2531        let mut new_excerpts = SumTree::default();
2532        let mut cursor = snapshot
2533            .excerpts
2534            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2535        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2536
2537        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2538        new_excerpts.append(prefix, &());
2539
2540        let mut excerpt = cursor.item().unwrap().clone();
2541        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2542
2543        excerpt.range.context.start = range.start;
2544        excerpt.range.context.end = range.end;
2545        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2546
2547        excerpt.text_summary = excerpt
2548            .buffer
2549            .text_summary_for_range(excerpt.range.context.clone());
2550
2551        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2552        let old_start_offset = cursor.start().1;
2553        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2554        let edit = Edit {
2555            old: old_start_offset..old_start_offset + old_text_len,
2556            new: new_start_offset..new_start_offset + new_text_len,
2557        };
2558
2559        if let Some(last_edit) = edits.last_mut() {
2560            if last_edit.old.end == edit.old.start {
2561                last_edit.old.end = edit.old.end;
2562                last_edit.new.end = edit.new.end;
2563            } else {
2564                edits.push(edit);
2565            }
2566        } else {
2567            edits.push(edit);
2568        }
2569
2570        new_excerpts.push(excerpt, &());
2571
2572        cursor.next(&());
2573
2574        new_excerpts.append(cursor.suffix(&()), &());
2575
2576        drop(cursor);
2577        snapshot.excerpts = new_excerpts;
2578
2579        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2580        cx.emit(Event::Edited {
2581            singleton_buffer_edited: false,
2582            edited_buffer: None,
2583        });
2584        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2585        cx.notify();
2586    }
2587
2588    pub fn expand_excerpts(
2589        &mut self,
2590        ids: impl IntoIterator<Item = ExcerptId>,
2591        line_count: u32,
2592        direction: ExpandExcerptDirection,
2593        cx: &mut Context<Self>,
2594    ) {
2595        if line_count == 0 {
2596            return;
2597        }
2598        self.sync(cx);
2599        let mut snapshot = self.snapshot.borrow_mut();
2600
2601        let ids = ids.into_iter().collect::<Vec<_>>();
2602        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2603        let mut new_excerpts = SumTree::default();
2604        let mut cursor = snapshot
2605            .excerpts
2606            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2607        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2608
2609        for locator in &locators {
2610            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2611            new_excerpts.append(prefix, &());
2612
2613            let mut excerpt = cursor.item().unwrap().clone();
2614            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2615
2616            let up_line_count = if direction.should_expand_up() {
2617                line_count
2618            } else {
2619                0
2620            };
2621
2622            let start_row = excerpt
2623                .range
2624                .context
2625                .start
2626                .to_point(&excerpt.buffer)
2627                .row
2628                .saturating_sub(up_line_count);
2629            let start_point = Point::new(start_row, 0);
2630            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2631
2632            let down_line_count = if direction.should_expand_down() {
2633                line_count
2634            } else {
2635                0
2636            };
2637
2638            let mut end_point = excerpt.buffer.clip_point(
2639                excerpt.range.context.end.to_point(&excerpt.buffer)
2640                    + Point::new(down_line_count, 0),
2641                Bias::Left,
2642            );
2643            end_point.column = excerpt.buffer.line_len(end_point.row);
2644            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2645            excerpt.max_buffer_row = end_point.row;
2646
2647            excerpt.text_summary = excerpt
2648                .buffer
2649                .text_summary_for_range(excerpt.range.context.clone());
2650
2651            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2652            let old_start_offset = cursor.start().1;
2653            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2654            let edit = Edit {
2655                old: old_start_offset..old_start_offset + old_text_len,
2656                new: new_start_offset..new_start_offset + new_text_len,
2657            };
2658
2659            if let Some(last_edit) = edits.last_mut() {
2660                if last_edit.old.end == edit.old.start {
2661                    last_edit.old.end = edit.old.end;
2662                    last_edit.new.end = edit.new.end;
2663                } else {
2664                    edits.push(edit);
2665                }
2666            } else {
2667                edits.push(edit);
2668            }
2669
2670            new_excerpts.push(excerpt, &());
2671
2672            cursor.next(&());
2673        }
2674
2675        new_excerpts.append(cursor.suffix(&()), &());
2676
2677        drop(cursor);
2678        snapshot.excerpts = new_excerpts;
2679
2680        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2681        cx.emit(Event::Edited {
2682            singleton_buffer_edited: false,
2683            edited_buffer: None,
2684        });
2685        cx.emit(Event::ExcerptsExpanded { ids });
2686        cx.notify();
2687    }
2688
2689    fn sync(&self, cx: &App) {
2690        let mut snapshot = self.snapshot.borrow_mut();
2691        let mut excerpts_to_edit = Vec::new();
2692        let mut non_text_state_updated = false;
2693        let mut is_dirty = false;
2694        let mut has_deleted_file = false;
2695        let mut has_conflict = false;
2696        let mut edited = false;
2697        let mut buffers = self.buffers.borrow_mut();
2698        for buffer_state in buffers.values_mut() {
2699            let buffer = buffer_state.buffer.read(cx);
2700            let version = buffer.version();
2701            let non_text_state_update_count = buffer.non_text_state_update_count();
2702
2703            let buffer_edited = version.changed_since(&buffer_state.last_version);
2704            let buffer_non_text_state_updated =
2705                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2706            if buffer_edited || buffer_non_text_state_updated {
2707                buffer_state.last_version = version;
2708                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2709                excerpts_to_edit.extend(
2710                    buffer_state
2711                        .excerpts
2712                        .iter()
2713                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2714                );
2715            }
2716
2717            edited |= buffer_edited;
2718            non_text_state_updated |= buffer_non_text_state_updated;
2719            is_dirty |= buffer.is_dirty();
2720            has_deleted_file |= buffer
2721                .file()
2722                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2723            has_conflict |= buffer.has_conflict();
2724        }
2725        if edited {
2726            snapshot.edit_count += 1;
2727        }
2728        if non_text_state_updated {
2729            snapshot.non_text_state_update_count += 1;
2730        }
2731        snapshot.is_dirty = is_dirty;
2732        snapshot.has_deleted_file = has_deleted_file;
2733        snapshot.has_conflict = has_conflict;
2734
2735        for (id, diff) in self.diffs.iter() {
2736            if snapshot.diffs.get(&id).is_none() {
2737                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2738            }
2739        }
2740
2741        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2742
2743        let mut edits = Vec::new();
2744        let mut new_excerpts = SumTree::default();
2745        let mut cursor = snapshot
2746            .excerpts
2747            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2748
2749        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2750            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2751            let old_excerpt = cursor.item().unwrap();
2752            let buffer = buffer.read(cx);
2753            let buffer_id = buffer.remote_id();
2754
2755            let mut new_excerpt;
2756            if buffer_edited {
2757                edits.extend(
2758                    buffer
2759                        .edits_since_in_range::<usize>(
2760                            old_excerpt.buffer.version(),
2761                            old_excerpt.range.context.clone(),
2762                        )
2763                        .map(|edit| {
2764                            let excerpt_old_start = cursor.start().1;
2765                            let excerpt_new_start =
2766                                ExcerptOffset::new(new_excerpts.summary().text.len);
2767                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2768                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2769                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2770                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2771                            Edit {
2772                                old: old_start..old_end,
2773                                new: new_start..new_end,
2774                            }
2775                        }),
2776                );
2777
2778                new_excerpt = Excerpt::new(
2779                    old_excerpt.id,
2780                    locator.clone(),
2781                    buffer_id,
2782                    buffer.snapshot(),
2783                    old_excerpt.range.clone(),
2784                    old_excerpt.has_trailing_newline,
2785                );
2786            } else {
2787                new_excerpt = old_excerpt.clone();
2788                new_excerpt.buffer = buffer.snapshot();
2789            }
2790
2791            new_excerpts.push(new_excerpt, &());
2792            cursor.next(&());
2793        }
2794        new_excerpts.append(cursor.suffix(&()), &());
2795
2796        drop(cursor);
2797        snapshot.excerpts = new_excerpts;
2798
2799        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2800    }
2801
2802    fn sync_diff_transforms(
2803        &self,
2804        snapshot: &mut MultiBufferSnapshot,
2805        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2806        change_kind: DiffChangeKind,
2807    ) {
2808        if excerpt_edits.is_empty() {
2809            return;
2810        }
2811
2812        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2813        let mut old_diff_transforms = snapshot
2814            .diff_transforms
2815            .cursor::<(ExcerptOffset, usize)>(&());
2816        let mut new_diff_transforms = SumTree::default();
2817        let mut old_expanded_hunks = HashSet::default();
2818        let mut output_edits = Vec::new();
2819        let mut output_delta = 0_isize;
2820        let mut at_transform_boundary = true;
2821        let mut end_of_current_insert = None;
2822
2823        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2824        while let Some(edit) = excerpt_edits.next() {
2825            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2826            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2827                excerpts.prev(&());
2828            }
2829
2830            // Keep any transforms that are before the edit.
2831            if at_transform_boundary {
2832                at_transform_boundary = false;
2833                let transforms_before_edit =
2834                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2835                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2836                if let Some(transform) = old_diff_transforms.item() {
2837                    if old_diff_transforms.end(&()).0 == edit.old.start
2838                        && old_diff_transforms.start().0 < edit.old.start
2839                    {
2840                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2841                        old_diff_transforms.next(&());
2842                    }
2843                }
2844            }
2845
2846            // Compute the start of the edit in output coordinates.
2847            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2848            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2849            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2850
2851            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2852                &edit,
2853                &mut excerpts,
2854                &mut old_diff_transforms,
2855                &mut new_diff_transforms,
2856                &mut end_of_current_insert,
2857                &mut old_expanded_hunks,
2858                &snapshot,
2859                change_kind,
2860            );
2861
2862            // Compute the end of the edit in output coordinates.
2863            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2864            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2865            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2866            let edit_new_end =
2867                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2868            let output_edit = Edit {
2869                old: edit_old_start..edit_old_end,
2870                new: edit_new_start..edit_new_end,
2871            };
2872
2873            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2874            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2875            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2876                output_edits.push(output_edit);
2877            }
2878
2879            // If this is the last edit that intersects the current diff transform,
2880            // then recreate the content up to the end of this transform, to prepare
2881            // for reusing additional slices of the old transforms.
2882            if excerpt_edits.peek().map_or(true, |next_edit| {
2883                next_edit.old.start >= old_diff_transforms.end(&()).0
2884            }) {
2885                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2886                    && match old_diff_transforms.item() {
2887                        Some(DiffTransform::BufferContent {
2888                            inserted_hunk_info: Some(hunk),
2889                            ..
2890                        }) => excerpts.item().is_some_and(|excerpt| {
2891                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2892                        }),
2893                        _ => true,
2894                    };
2895
2896                let mut excerpt_offset = edit.new.end;
2897                if !keep_next_old_transform {
2898                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2899                    old_diff_transforms.next(&());
2900                }
2901
2902                old_expanded_hunks.clear();
2903                self.push_buffer_content_transform(
2904                    &snapshot,
2905                    &mut new_diff_transforms,
2906                    excerpt_offset,
2907                    end_of_current_insert,
2908                );
2909                at_transform_boundary = true;
2910            }
2911        }
2912
2913        // Keep any transforms that are after the last edit.
2914        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2915
2916        // Ensure there's always at least one buffer content transform.
2917        if new_diff_transforms.is_empty() {
2918            new_diff_transforms.push(
2919                DiffTransform::BufferContent {
2920                    summary: Default::default(),
2921                    inserted_hunk_info: None,
2922                },
2923                &(),
2924            );
2925        }
2926
2927        self.subscriptions.publish(output_edits);
2928        drop(old_diff_transforms);
2929        drop(excerpts);
2930        snapshot.diff_transforms = new_diff_transforms;
2931        snapshot.edit_count += 1;
2932
2933        #[cfg(any(test, feature = "test-support"))]
2934        snapshot.check_invariants();
2935    }
2936
2937    #[allow(clippy::too_many_arguments)]
2938    fn recompute_diff_transforms_for_edit(
2939        &self,
2940        edit: &Edit<TypedOffset<Excerpt>>,
2941        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2942        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2943        new_diff_transforms: &mut SumTree<DiffTransform>,
2944        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2945        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2946        snapshot: &MultiBufferSnapshot,
2947        change_kind: DiffChangeKind,
2948    ) -> bool {
2949        log::trace!(
2950            "recomputing diff transform for edit {:?} => {:?}",
2951            edit.old.start.value..edit.old.end.value,
2952            edit.new.start.value..edit.new.end.value
2953        );
2954
2955        // Record which hunks were previously expanded.
2956        while let Some(item) = old_diff_transforms.item() {
2957            if let Some(hunk_info) = item.hunk_info() {
2958                log::trace!(
2959                    "previously expanded hunk at {}",
2960                    old_diff_transforms.start().0
2961                );
2962                old_expanded_hunks.insert(hunk_info);
2963            }
2964            if old_diff_transforms.end(&()).0 > edit.old.end {
2965                break;
2966            }
2967            old_diff_transforms.next(&());
2968        }
2969
2970        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2971        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2972        if old_expanded_hunks.is_empty()
2973            && change_kind == DiffChangeKind::BufferEdited
2974            && !all_diff_hunks_expanded
2975        {
2976            return false;
2977        }
2978
2979        // Visit each excerpt that intersects the edit.
2980        let mut did_expand_hunks = false;
2981        while let Some(excerpt) = excerpts.item() {
2982            // Recompute the expanded hunks in the portion of the excerpt that
2983            // intersects the edit.
2984            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2985                let buffer = &excerpt.buffer;
2986                let excerpt_start = *excerpts.start();
2987                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2988                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2989                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2990                let edit_buffer_start =
2991                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2992                let edit_buffer_end =
2993                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2994                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2995                let edit_anchor_range =
2996                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2997
2998                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2999                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3000                        continue;
3001                    }
3002
3003                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3004                    if hunk_buffer_range.start < excerpt_buffer_start {
3005                        log::trace!("skipping hunk that starts before excerpt");
3006                        continue;
3007                    }
3008
3009                    let hunk_info = DiffTransformHunkInfo {
3010                        excerpt_id: excerpt.id,
3011                        hunk_start_anchor: hunk.buffer_range.start,
3012                        hunk_secondary_status: hunk.secondary_status,
3013                    };
3014
3015                    let hunk_excerpt_start = excerpt_start
3016                        + ExcerptOffset::new(
3017                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3018                        );
3019                    let hunk_excerpt_end = excerpt_end.min(
3020                        excerpt_start
3021                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3022                    );
3023
3024                    self.push_buffer_content_transform(
3025                        snapshot,
3026                        new_diff_transforms,
3027                        hunk_excerpt_start,
3028                        *end_of_current_insert,
3029                    );
3030
3031                    // For every existing hunk, determine if it was previously expanded
3032                    // and if it should currently be expanded.
3033                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3034                    let should_expand_hunk = match &change_kind {
3035                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3036                            was_previously_expanded || all_diff_hunks_expanded
3037                        }
3038                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3039                            let intersects = hunk_buffer_range.is_empty()
3040                                || hunk_buffer_range.end > edit_buffer_start;
3041                            if *expand {
3042                                intersects || was_previously_expanded || all_diff_hunks_expanded
3043                            } else {
3044                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3045                            }
3046                        }
3047                        _ => was_previously_expanded || all_diff_hunks_expanded,
3048                    };
3049
3050                    if should_expand_hunk {
3051                        did_expand_hunks = true;
3052                        log::trace!(
3053                            "expanding hunk {:?}, excerpt:{:?}",
3054                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3055                            excerpt.id
3056                        );
3057
3058                        if !hunk.diff_base_byte_range.is_empty()
3059                            && hunk_buffer_range.start >= edit_buffer_start
3060                            && hunk_buffer_range.start <= excerpt_buffer_end
3061                        {
3062                            let base_text = diff.base_text();
3063                            let mut text_cursor =
3064                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3065                            let mut base_text_summary =
3066                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3067
3068                            let mut has_trailing_newline = false;
3069                            if base_text_summary.last_line_chars > 0 {
3070                                base_text_summary += TextSummary::newline();
3071                                has_trailing_newline = true;
3072                            }
3073
3074                            new_diff_transforms.push(
3075                                DiffTransform::DeletedHunk {
3076                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3077                                    summary: base_text_summary,
3078                                    buffer_id: excerpt.buffer_id,
3079                                    hunk_info,
3080                                    has_trailing_newline,
3081                                },
3082                                &(),
3083                            );
3084                        }
3085
3086                        if !hunk_buffer_range.is_empty() {
3087                            *end_of_current_insert =
3088                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3089                        }
3090                    }
3091                }
3092            }
3093
3094            if excerpts.end(&()) <= edit.new.end {
3095                excerpts.next(&());
3096            } else {
3097                break;
3098            }
3099        }
3100
3101        did_expand_hunks || !old_expanded_hunks.is_empty()
3102    }
3103
3104    fn append_diff_transforms(
3105        &self,
3106        new_transforms: &mut SumTree<DiffTransform>,
3107        subtree: SumTree<DiffTransform>,
3108    ) {
3109        if let Some(DiffTransform::BufferContent {
3110            inserted_hunk_info,
3111            summary,
3112        }) = subtree.first()
3113        {
3114            if self.extend_last_buffer_content_transform(
3115                new_transforms,
3116                *inserted_hunk_info,
3117                *summary,
3118            ) {
3119                let mut cursor = subtree.cursor::<()>(&());
3120                cursor.next(&());
3121                cursor.next(&());
3122                new_transforms.append(cursor.suffix(&()), &());
3123                return;
3124            }
3125        }
3126        new_transforms.append(subtree, &());
3127    }
3128
3129    fn push_diff_transform(
3130        &self,
3131        new_transforms: &mut SumTree<DiffTransform>,
3132        transform: DiffTransform,
3133    ) {
3134        if let DiffTransform::BufferContent {
3135            inserted_hunk_info: inserted_hunk_anchor,
3136            summary,
3137        } = transform
3138        {
3139            if self.extend_last_buffer_content_transform(
3140                new_transforms,
3141                inserted_hunk_anchor,
3142                summary,
3143            ) {
3144                return;
3145            }
3146        }
3147        new_transforms.push(transform, &());
3148    }
3149
3150    fn push_buffer_content_transform(
3151        &self,
3152        old_snapshot: &MultiBufferSnapshot,
3153        new_transforms: &mut SumTree<DiffTransform>,
3154        end_offset: ExcerptOffset,
3155        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3156    ) {
3157        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3158            (end_offset.min(insertion_end_offset), Some(hunk_info))
3159        });
3160        let unchanged_region = [(end_offset, None)];
3161
3162        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3163        {
3164            let start_offset = new_transforms.summary().excerpt_len();
3165            if end_offset <= start_offset {
3166                continue;
3167            }
3168            let summary_to_add = old_snapshot
3169                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3170
3171            if !self.extend_last_buffer_content_transform(
3172                new_transforms,
3173                inserted_hunk_info,
3174                summary_to_add,
3175            ) {
3176                new_transforms.push(
3177                    DiffTransform::BufferContent {
3178                        summary: summary_to_add,
3179                        inserted_hunk_info,
3180                    },
3181                    &(),
3182                )
3183            }
3184        }
3185    }
3186
3187    fn extend_last_buffer_content_transform(
3188        &self,
3189        new_transforms: &mut SumTree<DiffTransform>,
3190        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3191        summary_to_add: TextSummary,
3192    ) -> bool {
3193        let mut did_extend = false;
3194        new_transforms.update_last(
3195            |last_transform| {
3196                if let DiffTransform::BufferContent {
3197                    summary,
3198                    inserted_hunk_info: inserted_hunk_anchor,
3199                } = last_transform
3200                {
3201                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3202                        *summary += summary_to_add;
3203                        did_extend = true;
3204                    }
3205                }
3206            },
3207            &(),
3208        );
3209        did_extend
3210    }
3211}
3212
3213#[cfg(any(test, feature = "test-support"))]
3214impl MultiBuffer {
3215    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3216        let buffer = cx.new(|cx| Buffer::local(text, cx));
3217        cx.new(|cx| Self::singleton(buffer, cx))
3218    }
3219
3220    pub fn build_multi<const COUNT: usize>(
3221        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3222        cx: &mut gpui::App,
3223    ) -> Entity<Self> {
3224        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3225        for (text, ranges) in excerpts {
3226            let buffer = cx.new(|cx| Buffer::local(text, cx));
3227            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3228                context: range,
3229                primary: None,
3230            });
3231            multi.update(cx, |multi, cx| {
3232                multi.push_excerpts(buffer, excerpt_ranges, cx)
3233            });
3234        }
3235
3236        multi
3237    }
3238
3239    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3240        cx.new(|cx| Self::singleton(buffer, cx))
3241    }
3242
3243    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3244        cx.new(|cx| {
3245            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3246            let mutation_count = rng.gen_range(1..=5);
3247            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3248            multibuffer
3249        })
3250    }
3251
3252    pub fn randomly_edit(
3253        &mut self,
3254        rng: &mut impl rand::Rng,
3255        edit_count: usize,
3256        cx: &mut Context<Self>,
3257    ) {
3258        use util::RandomCharIter;
3259
3260        let snapshot = self.read(cx);
3261        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3262        let mut last_end = None;
3263        for _ in 0..edit_count {
3264            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3265                break;
3266            }
3267
3268            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3269            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3270            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3271            last_end = Some(end);
3272
3273            let mut range = start..end;
3274            if rng.gen_bool(0.2) {
3275                mem::swap(&mut range.start, &mut range.end);
3276            }
3277
3278            let new_text_len = rng.gen_range(0..10);
3279            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3280
3281            edits.push((range, new_text.into()));
3282        }
3283        log::info!("mutating multi-buffer with {:?}", edits);
3284        drop(snapshot);
3285
3286        self.edit(edits, None, cx);
3287    }
3288
3289    pub fn randomly_edit_excerpts(
3290        &mut self,
3291        rng: &mut impl rand::Rng,
3292        mutation_count: usize,
3293        cx: &mut Context<Self>,
3294    ) {
3295        use rand::prelude::*;
3296        use std::env;
3297        use util::RandomCharIter;
3298
3299        let max_excerpts = env::var("MAX_EXCERPTS")
3300            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3301            .unwrap_or(5);
3302
3303        let mut buffers = Vec::new();
3304        for _ in 0..mutation_count {
3305            if rng.gen_bool(0.05) {
3306                log::info!("Clearing multi-buffer");
3307                self.clear(cx);
3308                continue;
3309            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3310                let ids = self.excerpt_ids();
3311                let mut excerpts = HashSet::default();
3312                for _ in 0..rng.gen_range(0..ids.len()) {
3313                    excerpts.extend(ids.choose(rng).copied());
3314                }
3315
3316                let line_count = rng.gen_range(0..5);
3317
3318                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3319
3320                self.expand_excerpts(
3321                    excerpts.iter().cloned(),
3322                    line_count,
3323                    ExpandExcerptDirection::UpAndDown,
3324                    cx,
3325                );
3326                continue;
3327            }
3328
3329            let excerpt_ids = self.excerpt_ids();
3330            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3331                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3332                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3333                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3334                    let buffer = buffers.last().unwrap().read(cx);
3335                    log::info!(
3336                        "Creating new buffer {} with text: {:?}",
3337                        buffer.remote_id(),
3338                        buffer.text()
3339                    );
3340                    buffers.last().unwrap().clone()
3341                } else {
3342                    self.buffers
3343                        .borrow()
3344                        .values()
3345                        .choose(rng)
3346                        .unwrap()
3347                        .buffer
3348                        .clone()
3349                };
3350
3351                let buffer = buffer_handle.read(cx);
3352                let buffer_text = buffer.text();
3353                let ranges = (0..rng.gen_range(0..5))
3354                    .map(|_| {
3355                        let end_ix =
3356                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3357                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3358                        ExcerptRange {
3359                            context: start_ix..end_ix,
3360                            primary: None,
3361                        }
3362                    })
3363                    .collect::<Vec<_>>();
3364                log::info!(
3365                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3366                    buffer_handle.read(cx).remote_id(),
3367                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3368                    ranges
3369                        .iter()
3370                        .map(|r| &buffer_text[r.context.clone()])
3371                        .collect::<Vec<_>>()
3372                );
3373
3374                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3375                log::info!("Inserted with ids: {:?}", excerpt_id);
3376            } else {
3377                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3378                let mut excerpts_to_remove = excerpt_ids
3379                    .choose_multiple(rng, remove_count)
3380                    .cloned()
3381                    .collect::<Vec<_>>();
3382                let snapshot = self.snapshot.borrow();
3383                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3384                drop(snapshot);
3385                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3386                self.remove_excerpts(excerpts_to_remove, cx);
3387            }
3388        }
3389    }
3390
3391    pub fn randomly_mutate(
3392        &mut self,
3393        rng: &mut impl rand::Rng,
3394        mutation_count: usize,
3395        cx: &mut Context<Self>,
3396    ) {
3397        use rand::prelude::*;
3398
3399        if rng.gen_bool(0.7) || self.singleton {
3400            let buffer = self
3401                .buffers
3402                .borrow()
3403                .values()
3404                .choose(rng)
3405                .map(|state| state.buffer.clone());
3406
3407            if let Some(buffer) = buffer {
3408                buffer.update(cx, |buffer, cx| {
3409                    if rng.gen() {
3410                        buffer.randomly_edit(rng, mutation_count, cx);
3411                    } else {
3412                        buffer.randomly_undo_redo(rng, cx);
3413                    }
3414                });
3415            } else {
3416                self.randomly_edit(rng, mutation_count, cx);
3417            }
3418        } else {
3419            self.randomly_edit_excerpts(rng, mutation_count, cx);
3420        }
3421
3422        self.check_invariants(cx);
3423    }
3424
3425    fn check_invariants(&self, cx: &App) {
3426        self.read(cx).check_invariants();
3427    }
3428}
3429
3430impl EventEmitter<Event> for MultiBuffer {}
3431
3432impl MultiBufferSnapshot {
3433    pub fn text(&self) -> String {
3434        self.chunks(0..self.len(), false)
3435            .map(|chunk| chunk.text)
3436            .collect()
3437    }
3438
3439    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3440        self.reversed_chunks_in_range(0..position.to_offset(self))
3441            .flat_map(|c| c.chars().rev())
3442    }
3443
3444    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3445        let mut cursor = self.cursor::<usize>();
3446        cursor.seek(&range.end);
3447        let current_chunks = cursor.region().as_ref().map(|region| {
3448            let start_overshoot = range.start.saturating_sub(region.range.start);
3449            let end_overshoot = range.end - region.range.start;
3450            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3451            let start = region.buffer_range.start + start_overshoot;
3452            region.buffer.reversed_chunks_in_range(start..end)
3453        });
3454        ReversedMultiBufferChunks {
3455            cursor,
3456            current_chunks,
3457            start: range.start,
3458            offset: range.end,
3459        }
3460    }
3461
3462    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3463        let offset = position.to_offset(self);
3464        self.text_for_range(offset..self.len())
3465            .flat_map(|chunk| chunk.chars())
3466    }
3467
3468    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3469        self.chunks(range, false).map(|chunk| chunk.text)
3470    }
3471
3472    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3473        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3474            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3475    }
3476
3477    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3478    where
3479        T: ToOffset,
3480    {
3481        let position = position.to_offset(self);
3482        position == self.clip_offset(position, Bias::Left)
3483            && self
3484                .bytes_in_range(position..self.len())
3485                .flatten()
3486                .copied()
3487                .take(needle.len())
3488                .eq(needle.bytes())
3489    }
3490
3491    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3492        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3493    }
3494
3495    pub fn diff_hunks_in_range<T: ToPoint>(
3496        &self,
3497        range: Range<T>,
3498    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3499        let query_range = range.start.to_point(self)..range.end.to_point(self);
3500        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3501            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3502                log::debug!("no diff found for {:?}", buffer.remote_id());
3503                return None;
3504            };
3505            let buffer_start = buffer.anchor_before(buffer_range.start);
3506            let buffer_end = buffer.anchor_after(buffer_range.end);
3507            Some(
3508                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3509                    .filter_map(|hunk| {
3510                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3511                            return None;
3512                        }
3513                        Some((hunk.range.clone(), hunk))
3514                    }),
3515            )
3516        })
3517        .filter_map(move |(range, hunk, excerpt)| {
3518            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3519            {
3520                return None;
3521            }
3522            let end_row = if range.end.column == 0 {
3523                range.end.row
3524            } else {
3525                range.end.row + 1
3526            };
3527            Some(MultiBufferDiffHunk {
3528                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3529                buffer_id: excerpt.buffer_id,
3530                excerpt_id: excerpt.id,
3531                buffer_range: hunk.buffer_range.clone(),
3532                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3533                secondary_status: hunk.secondary_status,
3534            })
3535        })
3536    }
3537
3538    pub fn excerpt_ids_for_range<T: ToOffset>(
3539        &self,
3540        range: Range<T>,
3541    ) -> impl Iterator<Item = ExcerptId> + '_ {
3542        let range = range.start.to_offset(self)..range.end.to_offset(self);
3543        let mut cursor = self.cursor::<usize>();
3544        cursor.seek(&range.start);
3545        std::iter::from_fn(move || {
3546            let region = cursor.region()?;
3547            if region.range.start >= range.end {
3548                return None;
3549            }
3550            cursor.next_excerpt();
3551            Some(region.excerpt.id)
3552        })
3553    }
3554
3555    pub fn buffer_ids_for_range<T: ToOffset>(
3556        &self,
3557        range: Range<T>,
3558    ) -> impl Iterator<Item = BufferId> + '_ {
3559        let range = range.start.to_offset(self)..range.end.to_offset(self);
3560        let mut cursor = self.cursor::<usize>();
3561        cursor.seek(&range.start);
3562        std::iter::from_fn(move || {
3563            let region = cursor.region()?;
3564            if region.range.start > range.end
3565                || region.range.start == range.end && region.range.start > range.start
3566            {
3567                return None;
3568            }
3569            cursor.next_excerpt();
3570            Some(region.excerpt.buffer_id)
3571        })
3572    }
3573
3574    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3575        &self,
3576        ranges: impl Iterator<Item = Range<T>>,
3577    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3578        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3579    }
3580
3581    pub fn range_to_buffer_ranges<T: ToOffset>(
3582        &self,
3583        range: Range<T>,
3584    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3585        let start = range.start.to_offset(&self);
3586        let end = range.end.to_offset(&self);
3587
3588        let mut cursor = self.cursor::<usize>();
3589        cursor.seek(&start);
3590
3591        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3592        while let Some(region) = cursor.region() {
3593            if region.range.start > end {
3594                break;
3595            }
3596            if region.is_main_buffer {
3597                let start_overshoot = start.saturating_sub(region.range.start);
3598                let end_overshoot = end.saturating_sub(region.range.start);
3599                let start = region
3600                    .buffer_range
3601                    .end
3602                    .min(region.buffer_range.start + start_overshoot);
3603                let end = region
3604                    .buffer_range
3605                    .end
3606                    .min(region.buffer_range.start + end_overshoot);
3607                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3608                    *excerpt_id == region.excerpt.id && prev_range.end == start
3609                }) {
3610                    prev.1.end = end;
3611                } else {
3612                    result.push((region.buffer, start..end, region.excerpt.id));
3613                }
3614            }
3615            cursor.next();
3616        }
3617        result
3618    }
3619
3620    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3621        &self,
3622        range: Range<T>,
3623    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3624        let start = range.start.to_offset(&self);
3625        let end = range.end.to_offset(&self);
3626
3627        let mut cursor = self.cursor::<usize>();
3628        cursor.seek(&start);
3629
3630        std::iter::from_fn(move || {
3631            let region = cursor.region()?;
3632            if region.range.start > end {
3633                return None;
3634            }
3635            let start_overshoot = start.saturating_sub(region.range.start);
3636            let end_overshoot = end.saturating_sub(region.range.start);
3637            let start = region
3638                .buffer_range
3639                .end
3640                .min(region.buffer_range.start + start_overshoot);
3641            let end = region
3642                .buffer_range
3643                .end
3644                .min(region.buffer_range.start + end_overshoot);
3645
3646            let region_excerpt_id = region.excerpt.id;
3647            let deleted_hunk_anchor = if region.is_main_buffer {
3648                None
3649            } else {
3650                Some(self.anchor_before(region.range.start))
3651            };
3652            let result = (
3653                region.buffer,
3654                start..end,
3655                region_excerpt_id,
3656                deleted_hunk_anchor,
3657            );
3658            cursor.next();
3659            Some(result)
3660        })
3661    }
3662
3663    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3664    /// coordinates.
3665    ///
3666    /// The given callback will be called for every excerpt intersecting the given range. It will
3667    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3668    /// The callback should return an iterator of metadata items from that buffer, each paired
3669    /// with a buffer range.
3670    ///
3671    /// The returned iterator yields each of these metadata items, paired with its range in
3672    /// multi-buffer coordinates.
3673    fn lift_buffer_metadata<'a, D, M, I>(
3674        &'a self,
3675        query_range: Range<D>,
3676        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3677    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3678    where
3679        I: Iterator<Item = (Range<D>, M)> + 'a,
3680        D: TextDimension + Ord + Sub<D, Output = D>,
3681    {
3682        let max_position = D::from_text_summary(&self.text_summary());
3683        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3684        let mut cursor = self.cursor::<D>();
3685
3686        // Find the excerpt and buffer offset where the given range ends.
3687        cursor.seek(&query_range.end);
3688        let mut range_end = None;
3689        while let Some(region) = cursor.region() {
3690            if region.is_main_buffer {
3691                let mut buffer_end = region.buffer_range.start;
3692                let overshoot = if query_range.end > region.range.start {
3693                    query_range.end - region.range.start
3694                } else {
3695                    D::default()
3696                };
3697                buffer_end.add_assign(&overshoot);
3698                range_end = Some((region.excerpt.id, buffer_end));
3699                break;
3700            }
3701            cursor.next();
3702        }
3703
3704        cursor.seek(&query_range.start);
3705
3706        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3707            if region.range.start > D::zero(&()) {
3708                cursor.prev()
3709            }
3710        }
3711
3712        iter::from_fn(move || loop {
3713            let excerpt = cursor.excerpt()?;
3714
3715            // If we have already retrieved metadata for this excerpt, continue to use it.
3716            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3717                .as_mut()
3718                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3719            {
3720                Some(metadata)
3721            }
3722            // Otherwise, compute the intersection of the input range with the excerpt's range,
3723            // and retrieve the metadata for the resulting range.
3724            else {
3725                let region = cursor.region()?;
3726                let mut buffer_start;
3727                if region.is_main_buffer {
3728                    buffer_start = region.buffer_range.start;
3729                    if query_range.start > region.range.start {
3730                        let overshoot = query_range.start - region.range.start;
3731                        buffer_start.add_assign(&overshoot);
3732                    }
3733                    buffer_start = buffer_start.min(region.buffer_range.end);
3734                } else {
3735                    buffer_start = cursor.main_buffer_position()?;
3736                };
3737                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3738                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3739                    if excerpt.id == end_excerpt_id {
3740                        buffer_end = buffer_end.min(end_buffer_offset);
3741                    }
3742                }
3743
3744                if let Some(iterator) =
3745                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3746                {
3747                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3748                } else {
3749                    None
3750                }
3751            };
3752
3753            // Visit each metadata item.
3754            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3755            {
3756                // Find the multibuffer regions that contain the start and end of
3757                // the metadata item's range.
3758                if metadata_buffer_range.start > D::default() {
3759                    while let Some(region) = cursor.region() {
3760                        if region.is_main_buffer
3761                            && (region.buffer_range.end >= metadata_buffer_range.start
3762                                || cursor.is_at_end_of_excerpt())
3763                        {
3764                            break;
3765                        }
3766                        cursor.next();
3767                    }
3768                }
3769                let start_region = cursor.region()?;
3770                while let Some(region) = cursor.region() {
3771                    if region.is_main_buffer
3772                        && (region.buffer_range.end > metadata_buffer_range.end
3773                            || cursor.is_at_end_of_excerpt())
3774                    {
3775                        break;
3776                    }
3777                    cursor.next();
3778                }
3779                let end_region = cursor.region();
3780
3781                // Convert the metadata item's range into multibuffer coordinates.
3782                let mut start_position = start_region.range.start;
3783                let region_buffer_start = start_region.buffer_range.start;
3784                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3785                {
3786                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3787                    start_position = start_position.min(start_region.range.end);
3788                }
3789
3790                let mut end_position = max_position;
3791                if let Some(end_region) = &end_region {
3792                    end_position = end_region.range.start;
3793                    debug_assert!(end_region.is_main_buffer);
3794                    let region_buffer_start = end_region.buffer_range.start;
3795                    if metadata_buffer_range.end > region_buffer_start {
3796                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3797                    }
3798                    end_position = end_position.min(end_region.range.end);
3799                }
3800
3801                if start_position <= query_range.end && end_position >= query_range.start {
3802                    return Some((start_position..end_position, metadata, excerpt));
3803                }
3804            }
3805            // When there are no more metadata items for this excerpt, move to the next excerpt.
3806            else {
3807                current_excerpt_metadata.take();
3808                cursor.next_excerpt();
3809            }
3810        })
3811    }
3812
3813    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3814        let offset = position.to_offset(self);
3815
3816        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3817        cursor.seek(&DimensionPair {
3818            key: offset,
3819            value: None,
3820        });
3821        cursor.seek_to_start_of_current_excerpt();
3822        let excerpt = cursor.excerpt()?;
3823
3824        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3825        let current_position = self
3826            .anchor_before(offset)
3827            .text_anchor
3828            .to_offset(&excerpt.buffer);
3829        let excerpt_end = excerpt
3830            .buffer
3831            .anchor_before(excerpt_end.min(current_position));
3832
3833        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3834            for hunk in diff.hunks_intersecting_range_rev(
3835                excerpt.range.context.start..excerpt_end,
3836                &excerpt.buffer,
3837            ) {
3838                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3839                if hunk_end >= current_position {
3840                    continue;
3841                }
3842                let start =
3843                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3844                        .to_point(&self);
3845                return Some(MultiBufferRow(start.row));
3846            }
3847        }
3848
3849        loop {
3850            cursor.prev_excerpt();
3851            let excerpt = cursor.excerpt()?;
3852
3853            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3854                continue;
3855            };
3856            let mut hunks =
3857                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3858            let Some(hunk) = hunks.next() else {
3859                continue;
3860            };
3861            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3862                .to_point(&self);
3863            return Some(MultiBufferRow(start.row));
3864        }
3865    }
3866
3867    pub fn has_diff_hunks(&self) -> bool {
3868        self.diffs.values().any(|diff| !diff.is_empty())
3869    }
3870
3871    pub fn surrounding_word<T: ToOffset>(
3872        &self,
3873        start: T,
3874        for_completion: bool,
3875    ) -> (Range<usize>, Option<CharKind>) {
3876        let mut start = start.to_offset(self);
3877        let mut end = start;
3878        let mut next_chars = self.chars_at(start).peekable();
3879        let mut prev_chars = self.reversed_chars_at(start).peekable();
3880
3881        let classifier = self
3882            .char_classifier_at(start)
3883            .for_completion(for_completion);
3884
3885        let word_kind = cmp::max(
3886            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3887            next_chars.peek().copied().map(|c| classifier.kind(c)),
3888        );
3889
3890        for ch in prev_chars {
3891            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3892                start -= ch.len_utf8();
3893            } else {
3894                break;
3895            }
3896        }
3897
3898        for ch in next_chars {
3899            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3900                end += ch.len_utf8();
3901            } else {
3902                break;
3903            }
3904        }
3905
3906        (start..end, word_kind)
3907    }
3908
3909    pub fn is_singleton(&self) -> bool {
3910        self.singleton
3911    }
3912
3913    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3914        if self.singleton {
3915            self.excerpts
3916                .iter()
3917                .next()
3918                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3919        } else {
3920            None
3921        }
3922    }
3923
3924    pub fn len(&self) -> usize {
3925        self.diff_transforms.summary().output.len
3926    }
3927
3928    pub fn is_empty(&self) -> bool {
3929        self.excerpts.summary().text.len == 0
3930    }
3931
3932    pub fn widest_line_number(&self) -> u32 {
3933        self.excerpts.summary().widest_line_number + 1
3934    }
3935
3936    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3937        let range = range.start.to_offset(self)..range.end.to_offset(self);
3938        let mut excerpts = self.cursor::<usize>();
3939        excerpts.seek(&range.start);
3940
3941        let mut chunk;
3942        let mut has_trailing_newline;
3943        let excerpt_bytes;
3944        if let Some(region) = excerpts.region() {
3945            let mut bytes = region.buffer.bytes_in_range(
3946                region.buffer_range.start + range.start - region.range.start
3947                    ..(region.buffer_range.start + range.end - region.range.start)
3948                        .min(region.buffer_range.end),
3949            );
3950            chunk = bytes.next().unwrap_or(&[][..]);
3951            excerpt_bytes = Some(bytes);
3952            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3953            if chunk.is_empty() && has_trailing_newline {
3954                chunk = b"\n";
3955                has_trailing_newline = false;
3956            }
3957        } else {
3958            chunk = &[][..];
3959            excerpt_bytes = None;
3960            has_trailing_newline = false;
3961        };
3962
3963        MultiBufferBytes {
3964            range,
3965            cursor: excerpts,
3966            excerpt_bytes,
3967            has_trailing_newline,
3968            chunk,
3969        }
3970    }
3971
3972    pub fn reversed_bytes_in_range<T: ToOffset>(
3973        &self,
3974        range: Range<T>,
3975    ) -> ReversedMultiBufferBytes {
3976        let range = range.start.to_offset(self)..range.end.to_offset(self);
3977        let mut chunks = self.reversed_chunks_in_range(range.clone());
3978        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3979        ReversedMultiBufferBytes {
3980            range,
3981            chunks,
3982            chunk,
3983        }
3984    }
3985
3986    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3987        let mut cursor = self.cursor::<Point>();
3988        cursor.seek(&Point::new(start_row.0, 0));
3989        let mut result = MultiBufferRows {
3990            point: Point::new(0, 0),
3991            is_empty: self.excerpts.is_empty(),
3992            cursor,
3993        };
3994        result.seek(start_row);
3995        result
3996    }
3997
3998    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3999        let mut chunks = MultiBufferChunks {
4000            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4001            range: 0..0,
4002            excerpts: self.excerpts.cursor(&()),
4003            diff_transforms: self.diff_transforms.cursor(&()),
4004            diffs: &self.diffs,
4005            diff_base_chunks: None,
4006            excerpt_chunks: None,
4007            buffer_chunk: None,
4008            language_aware,
4009        };
4010        let range = range.start.to_offset(self)..range.end.to_offset(self);
4011        chunks.seek(range);
4012        chunks
4013    }
4014
4015    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4016        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4017    }
4018
4019    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4020        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4021    }
4022
4023    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4024        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4025    }
4026
4027    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4028        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4029            buffer.clip_point_utf16(Unclipped(point), bias)
4030        })
4031    }
4032
4033    pub fn offset_to_point(&self, offset: usize) -> Point {
4034        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4035    }
4036
4037    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4038        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4039    }
4040
4041    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4042        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4043    }
4044
4045    pub fn point_to_offset(&self, point: Point) -> usize {
4046        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4047    }
4048
4049    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4050        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4051    }
4052
4053    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4054        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4055    }
4056
4057    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4058        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4059    }
4060
4061    fn clip_dimension<D>(
4062        &self,
4063        position: D,
4064        bias: Bias,
4065        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4066    ) -> D
4067    where
4068        D: TextDimension + Ord + Sub<D, Output = D>,
4069    {
4070        let mut cursor = self.cursor();
4071        cursor.seek(&position);
4072        if let Some(region) = cursor.region() {
4073            if position >= region.range.end {
4074                return region.range.end;
4075            }
4076            let overshoot = position - region.range.start;
4077            let mut buffer_position = region.buffer_range.start;
4078            buffer_position.add_assign(&overshoot);
4079            let clipped_buffer_position =
4080                clip_buffer_position(&region.buffer, buffer_position, bias);
4081            let mut position = region.range.start;
4082            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4083            position
4084        } else {
4085            D::from_text_summary(&self.text_summary())
4086        }
4087    }
4088
4089    fn convert_dimension<D1, D2>(
4090        &self,
4091        key: D1,
4092        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4093    ) -> D2
4094    where
4095        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4096        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4097    {
4098        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4099        cursor.seek(&DimensionPair { key, value: None });
4100        if let Some(region) = cursor.region() {
4101            if key >= region.range.end.key {
4102                return region.range.end.value.unwrap();
4103            }
4104            let start_key = region.range.start.key;
4105            let start_value = region.range.start.value.unwrap();
4106            let buffer_start_key = region.buffer_range.start.key;
4107            let buffer_start_value = region.buffer_range.start.value.unwrap();
4108            let mut buffer_key = buffer_start_key;
4109            buffer_key.add_assign(&(key - start_key));
4110            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4111            let mut result = start_value;
4112            result.add_assign(&(buffer_value - buffer_start_value));
4113            result
4114        } else {
4115            D2::from_text_summary(&self.text_summary())
4116        }
4117    }
4118
4119    pub fn point_to_buffer_offset<T: ToOffset>(
4120        &self,
4121        point: T,
4122    ) -> Option<(&BufferSnapshot, usize)> {
4123        let offset = point.to_offset(self);
4124        let mut cursor = self.cursor::<usize>();
4125        cursor.seek(&offset);
4126        let region = cursor.region()?;
4127        let overshoot = offset - region.range.start;
4128        let buffer_offset = region.buffer_range.start + overshoot;
4129        Some((region.buffer, buffer_offset))
4130    }
4131
4132    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4133        let mut cursor = self.cursor::<Point>();
4134        cursor.seek(&point);
4135        let region = cursor.region()?;
4136        let overshoot = point - region.range.start;
4137        let buffer_offset = region.buffer_range.start + overshoot;
4138        Some((region.buffer, buffer_offset, region.is_main_buffer))
4139    }
4140
4141    pub fn suggested_indents(
4142        &self,
4143        rows: impl IntoIterator<Item = u32>,
4144        cx: &App,
4145    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4146        let mut result = BTreeMap::new();
4147
4148        let mut rows_for_excerpt = Vec::new();
4149        let mut cursor = self.cursor::<Point>();
4150        let mut rows = rows.into_iter().peekable();
4151        let mut prev_row = u32::MAX;
4152        let mut prev_language_indent_size = IndentSize::default();
4153
4154        while let Some(row) = rows.next() {
4155            cursor.seek(&Point::new(row, 0));
4156            let Some(region) = cursor.region() else {
4157                continue;
4158            };
4159
4160            // Retrieve the language and indent size once for each disjoint region being indented.
4161            let single_indent_size = if row.saturating_sub(1) == prev_row {
4162                prev_language_indent_size
4163            } else {
4164                region
4165                    .buffer
4166                    .language_indent_size_at(Point::new(row, 0), cx)
4167            };
4168            prev_language_indent_size = single_indent_size;
4169            prev_row = row;
4170
4171            let start_buffer_row = region.buffer_range.start.row;
4172            let start_multibuffer_row = region.range.start.row;
4173            let end_multibuffer_row = region.range.end.row;
4174
4175            rows_for_excerpt.push(row);
4176            while let Some(next_row) = rows.peek().copied() {
4177                if end_multibuffer_row > next_row {
4178                    rows_for_excerpt.push(next_row);
4179                    rows.next();
4180                } else {
4181                    break;
4182                }
4183            }
4184
4185            let buffer_rows = rows_for_excerpt
4186                .drain(..)
4187                .map(|row| start_buffer_row + row - start_multibuffer_row);
4188            let buffer_indents = region
4189                .buffer
4190                .suggested_indents(buffer_rows, single_indent_size);
4191            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4192                (
4193                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4194                    indent,
4195                )
4196            });
4197            result.extend(multibuffer_indents);
4198        }
4199
4200        result
4201    }
4202
4203    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4204        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4205            let mut size = buffer.indent_size_for_line(range.start.row);
4206            size.len = size
4207                .len
4208                .min(range.end.column)
4209                .saturating_sub(range.start.column);
4210            size
4211        } else {
4212            IndentSize::spaces(0)
4213        }
4214    }
4215
4216    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4217        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4218            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4219        } else {
4220            LineIndent::spaces(0)
4221        }
4222    }
4223
4224    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4225        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4226
4227        if self.settings_at(0, cx).extend_comment_on_newline {
4228            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4229                let delimiters = language_scope.line_comment_prefixes();
4230                for delimiter in delimiters {
4231                    if *self
4232                        .chars_at(Point::new(row.0, indent.len() as u32))
4233                        .take(delimiter.chars().count())
4234                        .collect::<String>()
4235                        .as_str()
4236                        == **delimiter
4237                    {
4238                        indent.push_str(&delimiter);
4239                        break;
4240                    }
4241                }
4242            }
4243        }
4244
4245        indent
4246    }
4247
4248    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4249    where
4250        T: ToOffset,
4251    {
4252        for char in self.reversed_chars_at(position) {
4253            if !char.is_whitespace() {
4254                return false;
4255            }
4256            if char == '\n' {
4257                return true;
4258            }
4259        }
4260        return true;
4261    }
4262
4263    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4264        while row.0 > 0 {
4265            row.0 -= 1;
4266            if !self.is_line_blank(row) {
4267                return Some(row);
4268            }
4269        }
4270        None
4271    }
4272
4273    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4274        if let Some((_, range)) = self.buffer_line_for_row(row) {
4275            range.end.column - range.start.column
4276        } else {
4277            0
4278        }
4279    }
4280
4281    pub fn buffer_line_for_row(
4282        &self,
4283        row: MultiBufferRow,
4284    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4285        let mut cursor = self.cursor::<Point>();
4286        let point = Point::new(row.0, 0);
4287        cursor.seek(&point);
4288        let region = cursor.region()?;
4289        let overshoot = point.min(region.range.end) - region.range.start;
4290        let buffer_point = region.buffer_range.start + overshoot;
4291        if buffer_point.row > region.buffer_range.end.row {
4292            return None;
4293        }
4294        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4295        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4296            .min(region.buffer_range.end);
4297        Some((region.buffer, line_start..line_end))
4298    }
4299
4300    pub fn max_point(&self) -> Point {
4301        self.text_summary().lines
4302    }
4303
4304    pub fn max_row(&self) -> MultiBufferRow {
4305        MultiBufferRow(self.text_summary().lines.row)
4306    }
4307
4308    pub fn text_summary(&self) -> TextSummary {
4309        self.diff_transforms.summary().output
4310    }
4311
4312    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4313    where
4314        D: TextDimension,
4315        O: ToOffset,
4316    {
4317        let range = range.start.to_offset(self)..range.end.to_offset(self);
4318        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4319        cursor.seek(&range.start, Bias::Right, &());
4320
4321        let Some(first_transform) = cursor.item() else {
4322            return D::from_text_summary(&TextSummary::default());
4323        };
4324
4325        let diff_transform_start = cursor.start().0;
4326        let diff_transform_end = cursor.end(&()).0;
4327        let diff_start = range.start;
4328        let start_overshoot = diff_start - diff_transform_start;
4329        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4330
4331        let mut result = match first_transform {
4332            DiffTransform::BufferContent { .. } => {
4333                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4334                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4335                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4336            }
4337            DiffTransform::DeletedHunk {
4338                buffer_id,
4339                base_text_byte_range,
4340                has_trailing_newline,
4341                ..
4342            } => {
4343                let buffer_start = base_text_byte_range.start + start_overshoot;
4344                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4345                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4346                    panic!("{:?} is in non-existent deleted hunk", range.start)
4347                };
4348
4349                let include_trailing_newline =
4350                    *has_trailing_newline && range.end >= diff_transform_end;
4351                if include_trailing_newline {
4352                    buffer_end -= 1;
4353                }
4354
4355                let mut summary =
4356                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4357
4358                if include_trailing_newline {
4359                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4360                }
4361
4362                summary
4363            }
4364        };
4365        if range.end < diff_transform_end {
4366            return result;
4367        }
4368
4369        cursor.next(&());
4370        result.add_assign(&D::from_text_summary(&cursor.summary(
4371            &range.end,
4372            Bias::Right,
4373            &(),
4374        )));
4375
4376        let Some(last_transform) = cursor.item() else {
4377            return result;
4378        };
4379
4380        let overshoot = range.end - cursor.start().0;
4381        let suffix = match last_transform {
4382            DiffTransform::BufferContent { .. } => {
4383                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4384                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4385            }
4386            DiffTransform::DeletedHunk {
4387                base_text_byte_range,
4388                buffer_id,
4389                has_trailing_newline,
4390                ..
4391            } => {
4392                let buffer_end = base_text_byte_range.start + overshoot;
4393                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4394                    panic!("{:?} is in non-existent deleted hunk", range.end)
4395                };
4396
4397                let mut suffix = base_text
4398                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4399                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4400                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4401                }
4402                suffix
4403            }
4404        };
4405
4406        result.add_assign(&suffix);
4407        result
4408    }
4409
4410    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4411    where
4412        D: TextDimension,
4413    {
4414        // let mut range = range.start..range.end;
4415        let mut summary = D::zero(&());
4416        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4417        cursor.seek(&range.start, Bias::Right, &());
4418        if let Some(excerpt) = cursor.item() {
4419            let mut end_before_newline = cursor.end(&());
4420            if excerpt.has_trailing_newline {
4421                end_before_newline -= ExcerptOffset::new(1);
4422            }
4423
4424            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4425            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4426            let end_in_excerpt =
4427                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4428            summary.add_assign(
4429                &excerpt
4430                    .buffer
4431                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4432            );
4433
4434            if range.end > end_before_newline {
4435                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4436            }
4437
4438            cursor.next(&());
4439        }
4440
4441        if range.end > *cursor.start() {
4442            summary.add_assign(
4443                &cursor
4444                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4445                    .0,
4446            );
4447            if let Some(excerpt) = cursor.item() {
4448                range.end = cmp::max(*cursor.start(), range.end);
4449
4450                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4451                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4452                summary.add_assign(
4453                    &excerpt
4454                        .buffer
4455                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4456                );
4457            }
4458        }
4459
4460        summary
4461    }
4462
4463    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4464    where
4465        D: TextDimension + Ord + Sub<D, Output = D>,
4466    {
4467        self.summaries_for_anchors([anchor])[0]
4468    }
4469
4470    fn resolve_summary_for_anchor<D>(
4471        &self,
4472        anchor: &Anchor,
4473        excerpt_position: D,
4474        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4475    ) -> D
4476    where
4477        D: TextDimension + Ord + Sub<D, Output = D>,
4478    {
4479        loop {
4480            let transform_end_position = diff_transforms.end(&()).0 .0;
4481            let at_transform_end =
4482                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4483            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4484                diff_transforms.next(&());
4485                continue;
4486            }
4487
4488            let mut position = diff_transforms.start().1 .0;
4489            match diff_transforms.item() {
4490                Some(DiffTransform::DeletedHunk {
4491                    buffer_id,
4492                    base_text_byte_range,
4493                    ..
4494                }) => {
4495                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4496                        if let Some(base_text) =
4497                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4498                        {
4499                            if base_text.can_resolve(&diff_base_anchor) {
4500                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4501                                if base_text_offset >= base_text_byte_range.start
4502                                    && base_text_offset <= base_text_byte_range.end
4503                                {
4504                                    let position_in_hunk = base_text
4505                                        .text_summary_for_range::<D, _>(
4506                                            base_text_byte_range.start..base_text_offset,
4507                                        );
4508                                    position.add_assign(&position_in_hunk);
4509                                } else if at_transform_end {
4510                                    diff_transforms.next(&());
4511                                    continue;
4512                                }
4513                            }
4514                        }
4515                    }
4516                }
4517                _ => {
4518                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4519                        diff_transforms.next(&());
4520                        continue;
4521                    }
4522                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4523                    position.add_assign(&overshoot);
4524                }
4525            }
4526
4527            return position;
4528        }
4529    }
4530
4531    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4532        let mut cursor = self
4533            .excerpts
4534            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4535        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4536
4537        cursor.seek(&Some(locator), Bias::Left, &());
4538        if cursor.item().is_none() {
4539            cursor.next(&());
4540        }
4541
4542        let mut position = cursor.start().1;
4543        if let Some(excerpt) = cursor.item() {
4544            if excerpt.id == anchor.excerpt_id {
4545                let excerpt_buffer_start = excerpt
4546                    .buffer
4547                    .offset_for_anchor(&excerpt.range.context.start);
4548                let excerpt_buffer_end =
4549                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4550                let buffer_position = cmp::min(
4551                    excerpt_buffer_end,
4552                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4553                );
4554                if buffer_position > excerpt_buffer_start {
4555                    position.value += buffer_position - excerpt_buffer_start;
4556                }
4557            }
4558        }
4559        position
4560    }
4561
4562    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4563    where
4564        D: TextDimension + Ord + Sub<D, Output = D>,
4565        I: 'a + IntoIterator<Item = &'a Anchor>,
4566    {
4567        let mut anchors = anchors.into_iter().peekable();
4568        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4569        let mut diff_transforms_cursor = self
4570            .diff_transforms
4571            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4572        diff_transforms_cursor.next(&());
4573
4574        let mut summaries = Vec::new();
4575        while let Some(anchor) = anchors.peek() {
4576            let excerpt_id = anchor.excerpt_id;
4577            let excerpt_anchors = iter::from_fn(|| {
4578                let anchor = anchors.peek()?;
4579                if anchor.excerpt_id == excerpt_id {
4580                    Some(anchors.next().unwrap())
4581                } else {
4582                    None
4583                }
4584            });
4585
4586            let locator = self.excerpt_locator_for_id(excerpt_id);
4587            cursor.seek_forward(locator, Bias::Left, &());
4588            if cursor.item().is_none() {
4589                cursor.next(&());
4590            }
4591
4592            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4593            if let Some(excerpt) = cursor.item() {
4594                if excerpt.id != excerpt_id {
4595                    let position = self.resolve_summary_for_anchor(
4596                        &Anchor::min(),
4597                        excerpt_start_position,
4598                        &mut diff_transforms_cursor,
4599                    );
4600                    summaries.extend(excerpt_anchors.map(|_| position));
4601                    continue;
4602                }
4603                let excerpt_buffer_start =
4604                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4605                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4606                for (buffer_summary, anchor) in excerpt
4607                    .buffer
4608                    .summaries_for_anchors_with_payload::<D, _, _>(
4609                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4610                    )
4611                {
4612                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4613                    let mut position = excerpt_start_position;
4614                    if summary > excerpt_buffer_start {
4615                        position.add_assign(&(summary - excerpt_buffer_start));
4616                    }
4617
4618                    if position > diff_transforms_cursor.start().0 .0 {
4619                        diff_transforms_cursor.seek_forward(
4620                            &ExcerptDimension(position),
4621                            Bias::Left,
4622                            &(),
4623                        );
4624                    }
4625
4626                    summaries.push(self.resolve_summary_for_anchor(
4627                        anchor,
4628                        position,
4629                        &mut diff_transforms_cursor,
4630                    ));
4631                }
4632            } else {
4633                diff_transforms_cursor.seek_forward(
4634                    &ExcerptDimension(excerpt_start_position),
4635                    Bias::Left,
4636                    &(),
4637                );
4638                let position = self.resolve_summary_for_anchor(
4639                    &Anchor::max(),
4640                    excerpt_start_position,
4641                    &mut diff_transforms_cursor,
4642                );
4643                summaries.extend(excerpt_anchors.map(|_| position));
4644            }
4645        }
4646
4647        summaries
4648    }
4649
4650    pub fn dimensions_from_points<'a, D>(
4651        &'a self,
4652        points: impl 'a + IntoIterator<Item = Point>,
4653    ) -> impl 'a + Iterator<Item = D>
4654    where
4655        D: TextDimension + Sub<D, Output = D>,
4656    {
4657        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4658        cursor.seek(&DimensionPair {
4659            key: Point::default(),
4660            value: None,
4661        });
4662        let mut points = points.into_iter();
4663        iter::from_fn(move || {
4664            let point = points.next()?;
4665
4666            cursor.seek_forward(&DimensionPair {
4667                key: point,
4668                value: None,
4669            });
4670
4671            if let Some(region) = cursor.region() {
4672                let overshoot = point - region.range.start.key;
4673                let buffer_point = region.buffer_range.start.key + overshoot;
4674                let mut position = region.range.start.value.unwrap();
4675                position.add_assign(
4676                    &region
4677                        .buffer
4678                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4679                );
4680                return Some(position);
4681            } else {
4682                return Some(D::from_text_summary(&self.text_summary()));
4683            }
4684        })
4685    }
4686
4687    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4688    where
4689        I: 'a + IntoIterator<Item = &'a Anchor>,
4690    {
4691        let mut anchors = anchors.into_iter().enumerate().peekable();
4692        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4693        cursor.next(&());
4694
4695        let mut result = Vec::new();
4696
4697        while let Some((_, anchor)) = anchors.peek() {
4698            let old_excerpt_id = anchor.excerpt_id;
4699
4700            // Find the location where this anchor's excerpt should be.
4701            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4702            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4703
4704            if cursor.item().is_none() {
4705                cursor.next(&());
4706            }
4707
4708            let next_excerpt = cursor.item();
4709            let prev_excerpt = cursor.prev_item();
4710
4711            // Process all of the anchors for this excerpt.
4712            while let Some((_, anchor)) = anchors.peek() {
4713                if anchor.excerpt_id != old_excerpt_id {
4714                    break;
4715                }
4716                let (anchor_ix, anchor) = anchors.next().unwrap();
4717                let mut anchor = *anchor;
4718
4719                // Leave min and max anchors unchanged if invalid or
4720                // if the old excerpt still exists at this location
4721                let mut kept_position = next_excerpt
4722                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4723                    || old_excerpt_id == ExcerptId::max()
4724                    || old_excerpt_id == ExcerptId::min();
4725
4726                // If the old excerpt no longer exists at this location, then attempt to
4727                // find an equivalent position for this anchor in an adjacent excerpt.
4728                if !kept_position {
4729                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4730                        if excerpt.contains(&anchor) {
4731                            anchor.excerpt_id = excerpt.id;
4732                            kept_position = true;
4733                            break;
4734                        }
4735                    }
4736                }
4737
4738                // If there's no adjacent excerpt that contains the anchor's position,
4739                // then report that the anchor has lost its position.
4740                if !kept_position {
4741                    anchor = if let Some(excerpt) = next_excerpt {
4742                        let mut text_anchor = excerpt
4743                            .range
4744                            .context
4745                            .start
4746                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4747                        if text_anchor
4748                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4749                            .is_gt()
4750                        {
4751                            text_anchor = excerpt.range.context.end;
4752                        }
4753                        Anchor {
4754                            buffer_id: Some(excerpt.buffer_id),
4755                            excerpt_id: excerpt.id,
4756                            text_anchor,
4757                            diff_base_anchor: None,
4758                        }
4759                    } else if let Some(excerpt) = prev_excerpt {
4760                        let mut text_anchor = excerpt
4761                            .range
4762                            .context
4763                            .end
4764                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4765                        if text_anchor
4766                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4767                            .is_lt()
4768                        {
4769                            text_anchor = excerpt.range.context.start;
4770                        }
4771                        Anchor {
4772                            buffer_id: Some(excerpt.buffer_id),
4773                            excerpt_id: excerpt.id,
4774                            text_anchor,
4775                            diff_base_anchor: None,
4776                        }
4777                    } else if anchor.text_anchor.bias == Bias::Left {
4778                        Anchor::min()
4779                    } else {
4780                        Anchor::max()
4781                    };
4782                }
4783
4784                result.push((anchor_ix, anchor, kept_position));
4785            }
4786        }
4787        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4788        result
4789    }
4790
4791    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4792        self.anchor_at(position, Bias::Left)
4793    }
4794
4795    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4796        self.anchor_at(position, Bias::Right)
4797    }
4798
4799    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4800        let offset = position.to_offset(self);
4801
4802        // Find the given position in the diff transforms. Determine the corresponding
4803        // offset in the excerpts, and whether the position is within a deleted hunk.
4804        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4805        diff_transforms.seek(&offset, Bias::Right, &());
4806
4807        if offset == diff_transforms.start().0 && bias == Bias::Left {
4808            if let Some(prev_item) = diff_transforms.prev_item() {
4809                match prev_item {
4810                    DiffTransform::DeletedHunk { .. } => {
4811                        diff_transforms.prev(&());
4812                    }
4813                    _ => {}
4814                }
4815            }
4816        }
4817        let offset_in_transform = offset - diff_transforms.start().0;
4818        let mut excerpt_offset = diff_transforms.start().1;
4819        let mut diff_base_anchor = None;
4820        if let Some(DiffTransform::DeletedHunk {
4821            buffer_id,
4822            base_text_byte_range,
4823            has_trailing_newline,
4824            ..
4825        }) = diff_transforms.item()
4826        {
4827            let diff = self.diffs.get(buffer_id).expect("missing diff");
4828            if offset_in_transform > base_text_byte_range.len() {
4829                debug_assert!(*has_trailing_newline);
4830                bias = Bias::Right;
4831            } else {
4832                diff_base_anchor = Some(
4833                    diff.base_text()
4834                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4835                );
4836                bias = Bias::Left;
4837            }
4838        } else {
4839            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4840        };
4841
4842        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4843            return Anchor {
4844                buffer_id: Some(buffer_id),
4845                excerpt_id: *excerpt_id,
4846                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4847                diff_base_anchor,
4848            };
4849        }
4850
4851        let mut excerpts = self
4852            .excerpts
4853            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4854        excerpts.seek(&excerpt_offset, Bias::Right, &());
4855        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4856            excerpts.prev(&());
4857        }
4858        if let Some(excerpt) = excerpts.item() {
4859            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4860            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4861                overshoot -= 1;
4862                bias = Bias::Right;
4863            }
4864
4865            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4866            let text_anchor =
4867                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4868            Anchor {
4869                buffer_id: Some(excerpt.buffer_id),
4870                excerpt_id: excerpt.id,
4871                text_anchor,
4872                diff_base_anchor,
4873            }
4874        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4875            Anchor::min()
4876        } else {
4877            Anchor::max()
4878        }
4879    }
4880
4881    /// Returns an anchor for the given excerpt and text anchor,
4882    /// returns None if the excerpt_id is no longer valid.
4883    pub fn anchor_in_excerpt(
4884        &self,
4885        excerpt_id: ExcerptId,
4886        text_anchor: text::Anchor,
4887    ) -> Option<Anchor> {
4888        let locator = self.excerpt_locator_for_id(excerpt_id);
4889        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4890        cursor.seek(locator, Bias::Left, &());
4891        if let Some(excerpt) = cursor.item() {
4892            if excerpt.id == excerpt_id {
4893                let text_anchor = excerpt.clip_anchor(text_anchor);
4894                drop(cursor);
4895                return Some(Anchor {
4896                    buffer_id: Some(excerpt.buffer_id),
4897                    excerpt_id,
4898                    text_anchor,
4899                    diff_base_anchor: None,
4900                });
4901            }
4902        }
4903        None
4904    }
4905
4906    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4907        Some(self.excerpt(excerpt_id)?.range.context.clone())
4908    }
4909
4910    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4911        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4912            true
4913        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4914            excerpt.buffer.can_resolve(&anchor.text_anchor)
4915        } else {
4916            false
4917        }
4918    }
4919
4920    pub fn excerpts(
4921        &self,
4922    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4923        self.excerpts
4924            .iter()
4925            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4926    }
4927
4928    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4929        let excerpts = self.excerpts.cursor(&());
4930        let diff_transforms = self.diff_transforms.cursor(&());
4931        MultiBufferCursor {
4932            excerpts,
4933            diff_transforms,
4934            diffs: &self.diffs,
4935            cached_region: None,
4936        }
4937    }
4938
4939    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4940        let start_locator = self.excerpt_locator_for_id(id);
4941        let mut excerpts = self
4942            .excerpts
4943            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4944        excerpts.seek(&Some(start_locator), Bias::Left, &());
4945        excerpts.prev(&());
4946
4947        let mut diff_transforms = self
4948            .diff_transforms
4949            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4950        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4951        if diff_transforms.end(&()).1 < excerpts.start().1 {
4952            diff_transforms.next(&());
4953        }
4954
4955        let excerpt = excerpts.item()?;
4956        Some(MultiBufferExcerpt {
4957            excerpt,
4958            offset: diff_transforms.start().0 .0,
4959            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4960            excerpt_offset: excerpts.start().1.clone(),
4961            diff_transforms,
4962        })
4963    }
4964
4965    pub fn excerpt_boundaries_in_range<R, T>(
4966        &self,
4967        range: R,
4968    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4969    where
4970        R: RangeBounds<T>,
4971        T: ToOffset,
4972    {
4973        let start_offset;
4974        let start = match range.start_bound() {
4975            Bound::Included(start) => {
4976                start_offset = start.to_offset(self);
4977                Bound::Included(start_offset)
4978            }
4979            Bound::Excluded(_) => {
4980                panic!("not supported")
4981            }
4982            Bound::Unbounded => {
4983                start_offset = 0;
4984                Bound::Unbounded
4985            }
4986        };
4987        let end = match range.end_bound() {
4988            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4989            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4990            Bound::Unbounded => Bound::Unbounded,
4991        };
4992        let bounds = (start, end);
4993
4994        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4995        cursor.seek(&DimensionPair {
4996            key: start_offset,
4997            value: None,
4998        });
4999
5000        if cursor
5001            .region()
5002            .is_some_and(|region| bounds.contains(&region.range.start.key))
5003        {
5004            cursor.prev_excerpt();
5005        } else {
5006            cursor.seek_to_start_of_current_excerpt();
5007        }
5008        let mut prev_region = cursor.region();
5009
5010        cursor.next_excerpt();
5011
5012        let mut visited_end = false;
5013        iter::from_fn(move || loop {
5014            if self.singleton {
5015                return None;
5016            }
5017
5018            let next_region = cursor.region();
5019            cursor.next_excerpt();
5020
5021            let next_region_start = if let Some(region) = &next_region {
5022                if !bounds.contains(&region.range.start.key) {
5023                    prev_region = next_region;
5024                    continue;
5025                }
5026                region.range.start.value.unwrap()
5027            } else {
5028                if !bounds.contains(&self.len()) {
5029                    return None;
5030                }
5031                self.max_point()
5032            };
5033            let next_region_end = if let Some(region) = cursor.region() {
5034                region.range.start.value.unwrap()
5035            } else {
5036                self.max_point()
5037            };
5038
5039            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5040                id: region.excerpt.id,
5041                buffer: region.excerpt.buffer.clone(),
5042                buffer_id: region.excerpt.buffer_id,
5043                range: region.excerpt.range.clone(),
5044                end_row: MultiBufferRow(next_region_start.row),
5045            });
5046
5047            let next = next_region.as_ref().map(|region| ExcerptInfo {
5048                id: region.excerpt.id,
5049                buffer: region.excerpt.buffer.clone(),
5050                buffer_id: region.excerpt.buffer_id,
5051                range: region.excerpt.range.clone(),
5052                end_row: if region.excerpt.has_trailing_newline {
5053                    MultiBufferRow(next_region_end.row - 1)
5054                } else {
5055                    MultiBufferRow(next_region_end.row)
5056                },
5057            });
5058
5059            if next.is_none() {
5060                if visited_end {
5061                    return None;
5062                } else {
5063                    visited_end = true;
5064                }
5065            }
5066
5067            let row = MultiBufferRow(next_region_start.row);
5068
5069            prev_region = next_region;
5070
5071            return Some(ExcerptBoundary { row, prev, next });
5072        })
5073    }
5074
5075    pub fn edit_count(&self) -> usize {
5076        self.edit_count
5077    }
5078
5079    pub fn non_text_state_update_count(&self) -> usize {
5080        self.non_text_state_update_count
5081    }
5082
5083    /// Returns the smallest enclosing bracket ranges containing the given range or
5084    /// None if no brackets contain range or the range is not contained in a single
5085    /// excerpt
5086    ///
5087    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5088    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5089        &self,
5090        range: Range<T>,
5091        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5092    ) -> Option<(Range<usize>, Range<usize>)> {
5093        let range = range.start.to_offset(self)..range.end.to_offset(self);
5094        let mut excerpt = self.excerpt_containing(range.clone())?;
5095        let buffer = excerpt.buffer();
5096        let excerpt_buffer_range = excerpt.buffer_range();
5097
5098        // Filter to ranges contained in the excerpt
5099        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5100            excerpt_buffer_range.contains(&open.start)
5101                && excerpt_buffer_range.contains(&close.end)
5102                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5103        };
5104
5105        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5106            excerpt.map_range_to_buffer(range),
5107            Some(&range_filter),
5108        )?;
5109
5110        Some((
5111            excerpt.map_range_from_buffer(open),
5112            excerpt.map_range_from_buffer(close),
5113        ))
5114    }
5115
5116    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5117    /// not contained in a single excerpt
5118    pub fn enclosing_bracket_ranges<T: ToOffset>(
5119        &self,
5120        range: Range<T>,
5121    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5122        let range = range.start.to_offset(self)..range.end.to_offset(self);
5123        let mut excerpt = self.excerpt_containing(range.clone())?;
5124
5125        Some(
5126            excerpt
5127                .buffer()
5128                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5129                .filter_map(move |pair| {
5130                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5131                        Some((
5132                            excerpt.map_range_from_buffer(pair.open_range),
5133                            excerpt.map_range_from_buffer(pair.close_range),
5134                        ))
5135                    } else {
5136                        None
5137                    }
5138                }),
5139        )
5140    }
5141
5142    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5143    /// not contained in a single excerpt
5144    pub fn text_object_ranges<T: ToOffset>(
5145        &self,
5146        range: Range<T>,
5147        options: TreeSitterOptions,
5148    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5149        let range = range.start.to_offset(self)..range.end.to_offset(self);
5150        self.excerpt_containing(range.clone())
5151            .map(|mut excerpt| {
5152                excerpt
5153                    .buffer()
5154                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5155                    .filter_map(move |(range, text_object)| {
5156                        if excerpt.contains_buffer_range(range.clone()) {
5157                            Some((excerpt.map_range_from_buffer(range), text_object))
5158                        } else {
5159                            None
5160                        }
5161                    })
5162            })
5163            .into_iter()
5164            .flatten()
5165    }
5166
5167    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5168    /// not contained in a single excerpt
5169    pub fn bracket_ranges<T: ToOffset>(
5170        &self,
5171        range: Range<T>,
5172    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5173        let range = range.start.to_offset(self)..range.end.to_offset(self);
5174        let mut excerpt = self.excerpt_containing(range.clone())?;
5175
5176        Some(
5177            excerpt
5178                .buffer()
5179                .bracket_ranges(excerpt.map_range_to_buffer(range))
5180                .filter_map(move |pair| {
5181                    let buffer_range = pair.open_range.start..pair.close_range.end;
5182                    if excerpt.contains_buffer_range(buffer_range) {
5183                        Some((
5184                            excerpt.map_range_from_buffer(pair.open_range),
5185                            excerpt.map_range_from_buffer(pair.close_range),
5186                        ))
5187                    } else {
5188                        None
5189                    }
5190                }),
5191        )
5192    }
5193
5194    pub fn redacted_ranges<'a, T: ToOffset>(
5195        &'a self,
5196        range: Range<T>,
5197        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5198    ) -> impl Iterator<Item = Range<usize>> + 'a {
5199        let range = range.start.to_offset(self)..range.end.to_offset(self);
5200        self.lift_buffer_metadata(range, move |buffer, range| {
5201            if redaction_enabled(buffer.file()) {
5202                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5203            } else {
5204                None
5205            }
5206        })
5207        .map(|(range, _, _)| range)
5208    }
5209
5210    pub fn runnable_ranges(
5211        &self,
5212        range: Range<Anchor>,
5213    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5214        let range = range.start.to_offset(self)..range.end.to_offset(self);
5215        self.lift_buffer_metadata(range, move |buffer, range| {
5216            Some(
5217                buffer
5218                    .runnable_ranges(range.clone())
5219                    .filter(move |runnable| {
5220                        runnable.run_range.start >= range.start
5221                            && runnable.run_range.end < range.end
5222                    })
5223                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5224            )
5225        })
5226        .map(|(run_range, runnable, _)| language::RunnableRange {
5227            run_range,
5228            ..runnable
5229        })
5230    }
5231
5232    pub fn line_indents(
5233        &self,
5234        start_row: MultiBufferRow,
5235        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5236    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5237        let max_point = self.max_point();
5238        let mut cursor = self.cursor::<Point>();
5239        cursor.seek(&Point::new(start_row.0, 0));
5240        iter::from_fn(move || {
5241            let mut region = cursor.region()?;
5242            while !buffer_filter(&region.excerpt.buffer) {
5243                cursor.next();
5244                region = cursor.region()?;
5245            }
5246            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5247            let buffer_start_row =
5248                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5249
5250            let buffer_end_row = if region.is_main_buffer
5251                && (region.has_trailing_newline || region.range.end == max_point)
5252            {
5253                region.buffer_range.end.row
5254            } else {
5255                region.buffer_range.end.row.saturating_sub(1)
5256            };
5257
5258            let line_indents = region
5259                .buffer
5260                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5261            cursor.next();
5262            return Some(line_indents.map(move |(buffer_row, indent)| {
5263                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5264                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5265            }));
5266        })
5267        .flatten()
5268    }
5269
5270    pub fn reversed_line_indents(
5271        &self,
5272        end_row: MultiBufferRow,
5273        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5274    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5275        let max_point = self.max_point();
5276        let mut cursor = self.cursor::<Point>();
5277        cursor.seek(&Point::new(end_row.0, 0));
5278        iter::from_fn(move || {
5279            let mut region = cursor.region()?;
5280            while !buffer_filter(&region.excerpt.buffer) {
5281                cursor.prev();
5282                region = cursor.region()?;
5283            }
5284
5285            let buffer_start_row = region.buffer_range.start.row;
5286            let buffer_end_row = if region.is_main_buffer
5287                && (region.has_trailing_newline || region.range.end == max_point)
5288            {
5289                region.buffer_range.end.row + 1
5290            } else {
5291                region.buffer_range.end.row
5292            };
5293
5294            let overshoot = end_row.0 - region.range.start.row;
5295            let buffer_end_row =
5296                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5297
5298            let line_indents = region
5299                .buffer
5300                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5301            cursor.prev();
5302            return Some(line_indents.map(move |(buffer_row, indent)| {
5303                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5304                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5305            }));
5306        })
5307        .flatten()
5308    }
5309
5310    pub async fn enclosing_indent(
5311        &self,
5312        mut target_row: MultiBufferRow,
5313    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5314        let max_row = MultiBufferRow(self.max_point().row);
5315        if target_row >= max_row {
5316            return None;
5317        }
5318
5319        let mut target_indent = self.line_indent_for_row(target_row);
5320
5321        // If the current row is at the start of an indented block, we want to return this
5322        // block as the enclosing indent.
5323        if !target_indent.is_line_empty() && target_row < max_row {
5324            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5325            if !next_line_indent.is_line_empty()
5326                && target_indent.raw_len() < next_line_indent.raw_len()
5327            {
5328                target_indent = next_line_indent;
5329                target_row.0 += 1;
5330            }
5331        }
5332
5333        const SEARCH_ROW_LIMIT: u32 = 25000;
5334        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5335        const YIELD_INTERVAL: u32 = 100;
5336
5337        let mut accessed_row_counter = 0;
5338
5339        // If there is a blank line at the current row, search for the next non indented lines
5340        if target_indent.is_line_empty() {
5341            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5342            let end =
5343                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5344
5345            let mut non_empty_line_above = None;
5346            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5347                if row < start {
5348                    break;
5349                }
5350                accessed_row_counter += 1;
5351                if accessed_row_counter == YIELD_INTERVAL {
5352                    accessed_row_counter = 0;
5353                    yield_now().await;
5354                }
5355                if !indent.is_line_empty() {
5356                    non_empty_line_above = Some((row, indent));
5357                    break;
5358                }
5359            }
5360
5361            let mut non_empty_line_below = None;
5362            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5363                if row > end {
5364                    break;
5365                }
5366                accessed_row_counter += 1;
5367                if accessed_row_counter == YIELD_INTERVAL {
5368                    accessed_row_counter = 0;
5369                    yield_now().await;
5370                }
5371                if !indent.is_line_empty() {
5372                    non_empty_line_below = Some((row, indent));
5373                    break;
5374                }
5375            }
5376
5377            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5378                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5379                    if above_indent.raw_len() >= below_indent.raw_len() {
5380                        (above_row, above_indent)
5381                    } else {
5382                        (below_row, below_indent)
5383                    }
5384                }
5385                (Some(above), None) => above,
5386                (None, Some(below)) => below,
5387                _ => return None,
5388            };
5389
5390            target_indent = indent;
5391            target_row = row;
5392        }
5393
5394        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5395        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5396
5397        let mut start_indent = None;
5398        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5399            if row < start {
5400                break;
5401            }
5402            accessed_row_counter += 1;
5403            if accessed_row_counter == YIELD_INTERVAL {
5404                accessed_row_counter = 0;
5405                yield_now().await;
5406            }
5407            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5408                start_indent = Some((row, indent));
5409                break;
5410            }
5411        }
5412        let (start_row, start_indent_size) = start_indent?;
5413
5414        let mut end_indent = (end, None);
5415        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5416            if row > end {
5417                break;
5418            }
5419            accessed_row_counter += 1;
5420            if accessed_row_counter == YIELD_INTERVAL {
5421                accessed_row_counter = 0;
5422                yield_now().await;
5423            }
5424            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5425                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5426                break;
5427            }
5428        }
5429        let (end_row, end_indent_size) = end_indent;
5430
5431        let indent = if let Some(end_indent_size) = end_indent_size {
5432            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5433                start_indent_size
5434            } else {
5435                end_indent_size
5436            }
5437        } else {
5438            start_indent_size
5439        };
5440
5441        Some((start_row..end_row, indent))
5442    }
5443
5444    pub fn indent_guides_in_range<T: ToPoint>(
5445        &self,
5446        range: Range<T>,
5447        ignore_disabled_for_language: bool,
5448        cx: &App,
5449    ) -> impl Iterator<Item = IndentGuide> {
5450        let range = range.start.to_point(self)..range.end.to_point(self);
5451        let start_row = MultiBufferRow(range.start.row);
5452        let end_row = MultiBufferRow(range.end.row);
5453
5454        let mut row_indents = self.line_indents(start_row, |buffer| {
5455            let settings =
5456                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5457            settings.indent_guides.enabled || ignore_disabled_for_language
5458        });
5459
5460        let mut result = Vec::new();
5461        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5462
5463        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5464            if first_row > end_row {
5465                break;
5466            }
5467            let current_depth = indent_stack.len() as u32;
5468
5469            let settings =
5470                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5471            let tab_size = settings.tab_size.get() as u32;
5472
5473            // When encountering empty, continue until found useful line indent
5474            // then add to the indent stack with the depth found
5475            let mut found_indent = false;
5476            let mut last_row = first_row;
5477            if line_indent.is_line_empty() {
5478                while !found_indent {
5479                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5480                        break;
5481                    };
5482                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5483                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5484                        break;
5485                    }
5486
5487                    if new_line_indent.is_line_empty() {
5488                        continue;
5489                    }
5490                    last_row = target_row.min(end_row);
5491                    line_indent = new_line_indent;
5492                    found_indent = true;
5493                    break;
5494                }
5495            } else {
5496                found_indent = true
5497            }
5498
5499            let depth = if found_indent {
5500                line_indent.len(tab_size) / tab_size
5501                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5502            } else {
5503                current_depth
5504            };
5505
5506            match depth.cmp(&current_depth) {
5507                cmp::Ordering::Less => {
5508                    for _ in 0..(current_depth - depth) {
5509                        let mut indent = indent_stack.pop().unwrap();
5510                        if last_row != first_row {
5511                            // In this case, we landed on an empty row, had to seek forward,
5512                            // and discovered that the indent we where on is ending.
5513                            // This means that the last display row must
5514                            // be on line that ends this indent range, so we
5515                            // should display the range up to the first non-empty line
5516                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5517                        }
5518
5519                        result.push(indent)
5520                    }
5521                }
5522                cmp::Ordering::Greater => {
5523                    for next_depth in current_depth..depth {
5524                        indent_stack.push(IndentGuide {
5525                            buffer_id: buffer.remote_id(),
5526                            start_row: first_row,
5527                            end_row: last_row,
5528                            depth: next_depth,
5529                            tab_size,
5530                            settings: settings.indent_guides,
5531                        });
5532                    }
5533                }
5534                _ => {}
5535            }
5536
5537            for indent in indent_stack.iter_mut() {
5538                indent.end_row = last_row;
5539            }
5540        }
5541
5542        result.extend(indent_stack);
5543        result.into_iter()
5544    }
5545
5546    pub fn trailing_excerpt_update_count(&self) -> usize {
5547        self.trailing_excerpt_update_count
5548    }
5549
5550    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5551        self.point_to_buffer_offset(point)
5552            .and_then(|(buffer, _)| buffer.file())
5553    }
5554
5555    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5556        self.point_to_buffer_offset(point)
5557            .and_then(|(buffer, offset)| buffer.language_at(offset))
5558    }
5559
5560    pub fn settings_at<'a, T: ToOffset>(
5561        &'a self,
5562        point: T,
5563        cx: &'a App,
5564    ) -> Cow<'a, LanguageSettings> {
5565        let mut language = None;
5566        let mut file = None;
5567        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5568            language = buffer.language_at(offset);
5569            file = buffer.file();
5570        }
5571        language_settings(language.map(|l| l.name()), file, cx)
5572    }
5573
5574    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5575        self.point_to_buffer_offset(point)
5576            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5577    }
5578
5579    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5580        self.point_to_buffer_offset(point)
5581            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5582            .unwrap_or_default()
5583    }
5584
5585    pub fn language_indent_size_at<T: ToOffset>(
5586        &self,
5587        position: T,
5588        cx: &App,
5589    ) -> Option<IndentSize> {
5590        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5591        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5592    }
5593
5594    pub fn is_dirty(&self) -> bool {
5595        self.is_dirty
5596    }
5597
5598    pub fn has_deleted_file(&self) -> bool {
5599        self.has_deleted_file
5600    }
5601
5602    pub fn has_conflict(&self) -> bool {
5603        self.has_conflict
5604    }
5605
5606    pub fn has_diagnostics(&self) -> bool {
5607        self.excerpts
5608            .iter()
5609            .any(|excerpt| excerpt.buffer.has_diagnostics())
5610    }
5611
5612    pub fn diagnostic_group(
5613        &self,
5614        buffer_id: BufferId,
5615        group_id: usize,
5616    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5617        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5618            if buffer.remote_id() != buffer_id {
5619                return None;
5620            };
5621            Some(
5622                buffer
5623                    .diagnostic_group(group_id)
5624                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5625            )
5626        })
5627        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5628    }
5629
5630    pub fn diagnostics_in_range<'a, T>(
5631        &'a self,
5632        range: Range<T>,
5633    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5634    where
5635        T: 'a
5636            + text::ToOffset
5637            + text::FromAnchor
5638            + TextDimension
5639            + Ord
5640            + Sub<T, Output = T>
5641            + fmt::Debug,
5642    {
5643        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5644            Some(
5645                buffer
5646                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5647                    .map(|entry| (entry.range, entry.diagnostic)),
5648            )
5649        })
5650        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5651    }
5652
5653    pub fn syntax_ancestor<T: ToOffset>(
5654        &self,
5655        range: Range<T>,
5656    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5657        let range = range.start.to_offset(self)..range.end.to_offset(self);
5658        let mut excerpt = self.excerpt_containing(range.clone())?;
5659        let node = excerpt
5660            .buffer()
5661            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5662        let node_range = node.byte_range();
5663        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5664            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5665        } else {
5666            MultiOrSingleBufferOffsetRange::Single(node_range)
5667        };
5668        Some((node, range))
5669    }
5670
5671    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5672        let (excerpt_id, _, buffer) = self.as_singleton()?;
5673        let outline = buffer.outline(theme)?;
5674        Some(Outline::new(
5675            outline
5676                .items
5677                .into_iter()
5678                .flat_map(|item| {
5679                    Some(OutlineItem {
5680                        depth: item.depth,
5681                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5682                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5683                        text: item.text,
5684                        highlight_ranges: item.highlight_ranges,
5685                        name_ranges: item.name_ranges,
5686                        body_range: item.body_range.and_then(|body_range| {
5687                            Some(
5688                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5689                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5690                            )
5691                        }),
5692                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5693                            Some(
5694                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5695                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5696                            )
5697                        }),
5698                    })
5699                })
5700                .collect(),
5701        ))
5702    }
5703
5704    pub fn symbols_containing<T: ToOffset>(
5705        &self,
5706        offset: T,
5707        theme: Option<&SyntaxTheme>,
5708    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5709        let anchor = self.anchor_before(offset);
5710        let excerpt_id = anchor.excerpt_id;
5711        let excerpt = self.excerpt(excerpt_id)?;
5712        Some((
5713            excerpt.buffer_id,
5714            excerpt
5715                .buffer
5716                .symbols_containing(anchor.text_anchor, theme)
5717                .into_iter()
5718                .flatten()
5719                .flat_map(|item| {
5720                    Some(OutlineItem {
5721                        depth: item.depth,
5722                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5723                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5724                        text: item.text,
5725                        highlight_ranges: item.highlight_ranges,
5726                        name_ranges: item.name_ranges,
5727                        body_range: item.body_range.and_then(|body_range| {
5728                            Some(
5729                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5730                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5731                            )
5732                        }),
5733                        annotation_range: item.annotation_range.and_then(|body_range| {
5734                            Some(
5735                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5736                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5737                            )
5738                        }),
5739                    })
5740                })
5741                .collect(),
5742        ))
5743    }
5744
5745    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5746        if id == ExcerptId::min() {
5747            Locator::min_ref()
5748        } else if id == ExcerptId::max() {
5749            Locator::max_ref()
5750        } else {
5751            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5752            cursor.seek(&id, Bias::Left, &());
5753            if let Some(entry) = cursor.item() {
5754                if entry.id == id {
5755                    return &entry.locator;
5756                }
5757            }
5758            panic!("invalid excerpt id {:?}", id)
5759        }
5760    }
5761
5762    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5763    fn excerpt_locators_for_ids(
5764        &self,
5765        ids: impl IntoIterator<Item = ExcerptId>,
5766    ) -> SmallVec<[Locator; 1]> {
5767        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5768        sorted_ids.sort_unstable();
5769        let mut locators = SmallVec::new();
5770
5771        while sorted_ids.last() == Some(&ExcerptId::max()) {
5772            sorted_ids.pop();
5773            if let Some(mapping) = self.excerpt_ids.last() {
5774                locators.push(mapping.locator.clone());
5775            }
5776        }
5777
5778        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5779        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5780            sorted_ids.next();
5781            if let Some(mapping) = self.excerpt_ids.first() {
5782                locators.push(mapping.locator.clone());
5783            }
5784        }
5785
5786        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5787        for id in sorted_ids {
5788            if cursor.seek_forward(&id, Bias::Left, &()) {
5789                locators.push(cursor.item().unwrap().locator.clone());
5790            } else {
5791                panic!("invalid excerpt id {:?}", id);
5792            }
5793        }
5794
5795        locators.sort_unstable();
5796        locators
5797    }
5798
5799    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5800        Some(self.excerpt(excerpt_id)?.buffer_id)
5801    }
5802
5803    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5804        Some(&self.excerpt(excerpt_id)?.buffer)
5805    }
5806
5807    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5808        let mut cursor = self
5809            .excerpts
5810            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5811        let locator = self.excerpt_locator_for_id(excerpt_id);
5812        if cursor.seek(&Some(locator), Bias::Left, &()) {
5813            let start = cursor.start().1.clone();
5814            let end = cursor.end(&()).1;
5815            let mut diff_transforms = self
5816                .diff_transforms
5817                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5818            diff_transforms.seek(&start, Bias::Left, &());
5819            let overshoot = start.0 - diff_transforms.start().0 .0;
5820            let start = diff_transforms.start().1 .0 + overshoot;
5821            diff_transforms.seek(&end, Bias::Right, &());
5822            let overshoot = end.0 - diff_transforms.start().0 .0;
5823            let end = diff_transforms.start().1 .0 + overshoot;
5824            Some(start..end)
5825        } else {
5826            None
5827        }
5828    }
5829
5830    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5831        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5832        let locator = self.excerpt_locator_for_id(excerpt_id);
5833        if cursor.seek(&Some(locator), Bias::Left, &()) {
5834            if let Some(excerpt) = cursor.item() {
5835                return Some(excerpt.range.context.clone());
5836            }
5837        }
5838        None
5839    }
5840
5841    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5842        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5843        let locator = self.excerpt_locator_for_id(excerpt_id);
5844        cursor.seek(&Some(locator), Bias::Left, &());
5845        if let Some(excerpt) = cursor.item() {
5846            if excerpt.id == excerpt_id {
5847                return Some(excerpt);
5848            }
5849        }
5850        None
5851    }
5852
5853    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5854    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5855        let range = range.start.to_offset(self)..range.end.to_offset(self);
5856        let mut cursor = self.cursor::<usize>();
5857        cursor.seek(&range.start);
5858
5859        let start_excerpt = cursor.excerpt()?;
5860        if range.end != range.start {
5861            cursor.seek_forward(&range.end);
5862            if cursor.excerpt()?.id != start_excerpt.id {
5863                return None;
5864            }
5865        }
5866
5867        cursor.seek_to_start_of_current_excerpt();
5868        let region = cursor.region()?;
5869        let offset = region.range.start;
5870        let buffer_offset = region.buffer_range.start;
5871        let excerpt_offset = cursor.excerpts.start().clone();
5872        Some(MultiBufferExcerpt {
5873            diff_transforms: cursor.diff_transforms,
5874            excerpt: start_excerpt,
5875            offset,
5876            buffer_offset,
5877            excerpt_offset,
5878        })
5879    }
5880
5881    pub fn selections_in_range<'a>(
5882        &'a self,
5883        range: &'a Range<Anchor>,
5884        include_local: bool,
5885    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5886        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5887        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5888        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5889        cursor.seek(start_locator, Bias::Left, &());
5890        cursor
5891            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5892            .flat_map(move |excerpt| {
5893                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5894                if excerpt.id == range.start.excerpt_id {
5895                    query_range.start = range.start.text_anchor;
5896                }
5897                if excerpt.id == range.end.excerpt_id {
5898                    query_range.end = range.end.text_anchor;
5899                }
5900
5901                excerpt
5902                    .buffer
5903                    .selections_in_range(query_range, include_local)
5904                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5905                        selections.map(move |selection| {
5906                            let mut start = Anchor {
5907                                buffer_id: Some(excerpt.buffer_id),
5908                                excerpt_id: excerpt.id,
5909                                text_anchor: selection.start,
5910                                diff_base_anchor: None,
5911                            };
5912                            let mut end = Anchor {
5913                                buffer_id: Some(excerpt.buffer_id),
5914                                excerpt_id: excerpt.id,
5915                                text_anchor: selection.end,
5916                                diff_base_anchor: None,
5917                            };
5918                            if range.start.cmp(&start, self).is_gt() {
5919                                start = range.start;
5920                            }
5921                            if range.end.cmp(&end, self).is_lt() {
5922                                end = range.end;
5923                            }
5924
5925                            (
5926                                replica_id,
5927                                line_mode,
5928                                cursor_shape,
5929                                Selection {
5930                                    id: selection.id,
5931                                    start,
5932                                    end,
5933                                    reversed: selection.reversed,
5934                                    goal: selection.goal,
5935                                },
5936                            )
5937                        })
5938                    })
5939            })
5940    }
5941
5942    pub fn show_headers(&self) -> bool {
5943        self.show_headers
5944    }
5945
5946    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5947        self.diffs.get(&buffer_id)
5948    }
5949}
5950
5951#[cfg(any(test, feature = "test-support"))]
5952impl MultiBufferSnapshot {
5953    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5954        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5955        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5956        start..end
5957    }
5958
5959    #[cfg(any(test, feature = "test-support"))]
5960    fn check_invariants(&self) {
5961        let excerpts = self.excerpts.items(&());
5962        let excerpt_ids = self.excerpt_ids.items(&());
5963
5964        for (ix, excerpt) in excerpts.iter().enumerate() {
5965            if ix == 0 {
5966                if excerpt.locator <= Locator::min() {
5967                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5968                }
5969            } else if excerpt.locator <= excerpts[ix - 1].locator {
5970                panic!("excerpts are out-of-order: {:?}", excerpts);
5971            }
5972        }
5973
5974        for (ix, entry) in excerpt_ids.iter().enumerate() {
5975            if ix == 0 {
5976                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5977                    panic!("invalid first excerpt id {:?}", entry.id);
5978                }
5979            } else if entry.id <= excerpt_ids[ix - 1].id {
5980                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5981            }
5982        }
5983
5984        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5985            panic!(
5986                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5987                self.excerpts.summary().text.len,
5988                self.diff_transforms.summary().input,
5989                self.diff_transforms.items(&()),
5990            );
5991        }
5992
5993        let mut prev_transform: Option<&DiffTransform> = None;
5994        for item in self.diff_transforms.iter() {
5995            if let DiffTransform::BufferContent {
5996                summary,
5997                inserted_hunk_info,
5998            } = item
5999            {
6000                if let Some(DiffTransform::BufferContent {
6001                    inserted_hunk_info: prev_inserted_hunk_info,
6002                    ..
6003                }) = prev_transform
6004                {
6005                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6006                        panic!(
6007                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6008                            self.diff_transforms.items(&()));
6009                    }
6010                }
6011                if summary.len == 0 && !self.is_empty() {
6012                    panic!("empty buffer content transform");
6013                }
6014            }
6015            prev_transform = Some(item);
6016        }
6017    }
6018}
6019
6020impl<'a, D> MultiBufferCursor<'a, D>
6021where
6022    D: TextDimension + Ord + Sub<D, Output = D>,
6023{
6024    fn seek(&mut self, position: &D) {
6025        self.cached_region.take();
6026        self.diff_transforms
6027            .seek(&OutputDimension(*position), Bias::Right, &());
6028        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6029            self.diff_transforms.prev(&());
6030        }
6031
6032        let mut excerpt_position = self.diff_transforms.start().1 .0;
6033        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6034            let overshoot = *position - self.diff_transforms.start().0 .0;
6035            excerpt_position.add_assign(&overshoot);
6036        }
6037
6038        self.excerpts
6039            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6040        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6041            self.excerpts.prev(&());
6042        }
6043    }
6044
6045    fn seek_forward(&mut self, position: &D) {
6046        self.cached_region.take();
6047        self.diff_transforms
6048            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6049        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6050            self.diff_transforms.prev(&());
6051        }
6052
6053        let overshoot = *position - self.diff_transforms.start().0 .0;
6054        let mut excerpt_position = self.diff_transforms.start().1 .0;
6055        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6056            excerpt_position.add_assign(&overshoot);
6057        }
6058
6059        self.excerpts
6060            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6061        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6062            self.excerpts.prev(&());
6063        }
6064    }
6065
6066    fn next_excerpt(&mut self) {
6067        self.excerpts.next(&());
6068        self.seek_to_start_of_current_excerpt();
6069    }
6070
6071    fn prev_excerpt(&mut self) {
6072        self.excerpts.prev(&());
6073        self.seek_to_start_of_current_excerpt();
6074    }
6075
6076    fn seek_to_start_of_current_excerpt(&mut self) {
6077        self.cached_region.take();
6078        self.diff_transforms
6079            .seek(self.excerpts.start(), Bias::Left, &());
6080        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6081            && self.diff_transforms.start().1 < *self.excerpts.start()
6082            && self.diff_transforms.next_item().is_some()
6083        {
6084            self.diff_transforms.next(&());
6085        }
6086    }
6087
6088    fn next(&mut self) {
6089        self.cached_region.take();
6090        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6091            cmp::Ordering::Less => self.diff_transforms.next(&()),
6092            cmp::Ordering::Greater => self.excerpts.next(&()),
6093            cmp::Ordering::Equal => {
6094                self.diff_transforms.next(&());
6095                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6096                    || self.diff_transforms.item().is_none()
6097                {
6098                    self.excerpts.next(&());
6099                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6100                    self.diff_transforms.item()
6101                {
6102                    if self
6103                        .excerpts
6104                        .item()
6105                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6106                    {
6107                        self.excerpts.next(&());
6108                    }
6109                }
6110            }
6111        }
6112    }
6113
6114    fn prev(&mut self) {
6115        self.cached_region.take();
6116        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6117            cmp::Ordering::Less => self.excerpts.prev(&()),
6118            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6119            cmp::Ordering::Equal => {
6120                self.diff_transforms.prev(&());
6121                if self.diff_transforms.start().1 < *self.excerpts.start()
6122                    || self.diff_transforms.item().is_none()
6123                {
6124                    self.excerpts.prev(&());
6125                }
6126            }
6127        }
6128    }
6129
6130    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6131        if self.cached_region.is_none() {
6132            self.cached_region = self.build_region();
6133        }
6134        self.cached_region.clone()
6135    }
6136
6137    fn is_at_end_of_excerpt(&mut self) -> bool {
6138        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6139            return false;
6140        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6141            || self.diff_transforms.item().is_none()
6142        {
6143            return true;
6144        }
6145
6146        let next_transform = self.diff_transforms.next_item();
6147        next_transform.map_or(true, |next_transform| match next_transform {
6148            DiffTransform::BufferContent { .. } => true,
6149            DiffTransform::DeletedHunk { hunk_info, .. } => self
6150                .excerpts
6151                .item()
6152                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6153        })
6154    }
6155
6156    fn main_buffer_position(&self) -> Option<D> {
6157        let excerpt = self.excerpts.item()?;
6158        let buffer = &excerpt.buffer;
6159        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6160        let mut buffer_start = buffer_context_start;
6161        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6162        buffer_start.add_assign(&overshoot);
6163        Some(buffer_start)
6164    }
6165
6166    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6167        let excerpt = self.excerpts.item()?;
6168        match self.diff_transforms.item()? {
6169            DiffTransform::DeletedHunk {
6170                buffer_id,
6171                base_text_byte_range,
6172                has_trailing_newline,
6173                hunk_info,
6174                ..
6175            } => {
6176                let diff = self.diffs.get(&buffer_id)?;
6177                let buffer = diff.base_text();
6178                let mut rope_cursor = buffer.as_rope().cursor(0);
6179                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6180                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6181                let mut buffer_end = buffer_start;
6182                buffer_end.add_assign(&buffer_range_len);
6183                let start = self.diff_transforms.start().0 .0;
6184                let end = self.diff_transforms.end(&()).0 .0;
6185                return Some(MultiBufferRegion {
6186                    buffer,
6187                    excerpt,
6188                    has_trailing_newline: *has_trailing_newline,
6189                    is_main_buffer: false,
6190                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6191                        hunk_info.hunk_secondary_status,
6192                    )),
6193                    buffer_range: buffer_start..buffer_end,
6194                    range: start..end,
6195                });
6196            }
6197            DiffTransform::BufferContent {
6198                inserted_hunk_info, ..
6199            } => {
6200                let buffer = &excerpt.buffer;
6201                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6202
6203                let mut start = self.diff_transforms.start().0 .0;
6204                let mut buffer_start = buffer_context_start;
6205                if self.diff_transforms.start().1 < *self.excerpts.start() {
6206                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6207                    start.add_assign(&overshoot);
6208                } else {
6209                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6210                    buffer_start.add_assign(&overshoot);
6211                }
6212
6213                let mut end;
6214                let mut buffer_end;
6215                let has_trailing_newline;
6216                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6217                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6218                    end = self.diff_transforms.end(&()).0 .0;
6219                    buffer_end = buffer_context_start;
6220                    buffer_end.add_assign(&overshoot);
6221                    has_trailing_newline = false;
6222                } else {
6223                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6224                    end = self.diff_transforms.start().0 .0;
6225                    end.add_assign(&overshoot);
6226                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6227                    has_trailing_newline = excerpt.has_trailing_newline;
6228                };
6229
6230                Some(MultiBufferRegion {
6231                    buffer,
6232                    excerpt,
6233                    has_trailing_newline,
6234                    is_main_buffer: true,
6235                    diff_hunk_status: inserted_hunk_info
6236                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6237                    buffer_range: buffer_start..buffer_end,
6238                    range: start..end,
6239                })
6240            }
6241        }
6242    }
6243
6244    fn excerpt(&self) -> Option<&'a Excerpt> {
6245        self.excerpts.item()
6246    }
6247}
6248
6249impl History {
6250    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6251        self.transaction_depth += 1;
6252        if self.transaction_depth == 1 {
6253            let id = self.next_transaction_id.tick();
6254            self.undo_stack.push(Transaction {
6255                id,
6256                buffer_transactions: Default::default(),
6257                first_edit_at: now,
6258                last_edit_at: now,
6259                suppress_grouping: false,
6260            });
6261            Some(id)
6262        } else {
6263            None
6264        }
6265    }
6266
6267    fn end_transaction(
6268        &mut self,
6269        now: Instant,
6270        buffer_transactions: HashMap<BufferId, TransactionId>,
6271    ) -> bool {
6272        assert_ne!(self.transaction_depth, 0);
6273        self.transaction_depth -= 1;
6274        if self.transaction_depth == 0 {
6275            if buffer_transactions.is_empty() {
6276                self.undo_stack.pop();
6277                false
6278            } else {
6279                self.redo_stack.clear();
6280                let transaction = self.undo_stack.last_mut().unwrap();
6281                transaction.last_edit_at = now;
6282                for (buffer_id, transaction_id) in buffer_transactions {
6283                    transaction
6284                        .buffer_transactions
6285                        .entry(buffer_id)
6286                        .or_insert(transaction_id);
6287                }
6288                true
6289            }
6290        } else {
6291            false
6292        }
6293    }
6294
6295    fn push_transaction<'a, T>(
6296        &mut self,
6297        buffer_transactions: T,
6298        now: Instant,
6299        cx: &Context<MultiBuffer>,
6300    ) where
6301        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6302    {
6303        assert_eq!(self.transaction_depth, 0);
6304        let transaction = Transaction {
6305            id: self.next_transaction_id.tick(),
6306            buffer_transactions: buffer_transactions
6307                .into_iter()
6308                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6309                .collect(),
6310            first_edit_at: now,
6311            last_edit_at: now,
6312            suppress_grouping: false,
6313        };
6314        if !transaction.buffer_transactions.is_empty() {
6315            self.undo_stack.push(transaction);
6316            self.redo_stack.clear();
6317        }
6318    }
6319
6320    fn finalize_last_transaction(&mut self) {
6321        if let Some(transaction) = self.undo_stack.last_mut() {
6322            transaction.suppress_grouping = true;
6323        }
6324    }
6325
6326    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6327        if let Some(ix) = self
6328            .undo_stack
6329            .iter()
6330            .rposition(|transaction| transaction.id == transaction_id)
6331        {
6332            Some(self.undo_stack.remove(ix))
6333        } else if let Some(ix) = self
6334            .redo_stack
6335            .iter()
6336            .rposition(|transaction| transaction.id == transaction_id)
6337        {
6338            Some(self.redo_stack.remove(ix))
6339        } else {
6340            None
6341        }
6342    }
6343
6344    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6345        self.undo_stack
6346            .iter()
6347            .find(|transaction| transaction.id == transaction_id)
6348            .or_else(|| {
6349                self.redo_stack
6350                    .iter()
6351                    .find(|transaction| transaction.id == transaction_id)
6352            })
6353    }
6354
6355    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6356        self.undo_stack
6357            .iter_mut()
6358            .find(|transaction| transaction.id == transaction_id)
6359            .or_else(|| {
6360                self.redo_stack
6361                    .iter_mut()
6362                    .find(|transaction| transaction.id == transaction_id)
6363            })
6364    }
6365
6366    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6367        assert_eq!(self.transaction_depth, 0);
6368        if let Some(transaction) = self.undo_stack.pop() {
6369            self.redo_stack.push(transaction);
6370            self.redo_stack.last_mut()
6371        } else {
6372            None
6373        }
6374    }
6375
6376    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6377        assert_eq!(self.transaction_depth, 0);
6378        if let Some(transaction) = self.redo_stack.pop() {
6379            self.undo_stack.push(transaction);
6380            self.undo_stack.last_mut()
6381        } else {
6382            None
6383        }
6384    }
6385
6386    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6387        let ix = self
6388            .undo_stack
6389            .iter()
6390            .rposition(|transaction| transaction.id == transaction_id)?;
6391        let transaction = self.undo_stack.remove(ix);
6392        self.redo_stack.push(transaction);
6393        self.redo_stack.last()
6394    }
6395
6396    fn group(&mut self) -> Option<TransactionId> {
6397        let mut count = 0;
6398        let mut transactions = self.undo_stack.iter();
6399        if let Some(mut transaction) = transactions.next_back() {
6400            while let Some(prev_transaction) = transactions.next_back() {
6401                if !prev_transaction.suppress_grouping
6402                    && transaction.first_edit_at - prev_transaction.last_edit_at
6403                        <= self.group_interval
6404                {
6405                    transaction = prev_transaction;
6406                    count += 1;
6407                } else {
6408                    break;
6409                }
6410            }
6411        }
6412        self.group_trailing(count)
6413    }
6414
6415    fn group_until(&mut self, transaction_id: TransactionId) {
6416        let mut count = 0;
6417        for transaction in self.undo_stack.iter().rev() {
6418            if transaction.id == transaction_id {
6419                self.group_trailing(count);
6420                break;
6421            } else if transaction.suppress_grouping {
6422                break;
6423            } else {
6424                count += 1;
6425            }
6426        }
6427    }
6428
6429    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6430        let new_len = self.undo_stack.len() - n;
6431        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6432        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6433            if let Some(transaction) = transactions_to_merge.last() {
6434                last_transaction.last_edit_at = transaction.last_edit_at;
6435            }
6436            for to_merge in transactions_to_merge {
6437                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6438                    last_transaction
6439                        .buffer_transactions
6440                        .entry(*buffer_id)
6441                        .or_insert(*transaction_id);
6442                }
6443            }
6444        }
6445
6446        self.undo_stack.truncate(new_len);
6447        self.undo_stack.last().map(|t| t.id)
6448    }
6449}
6450
6451impl Excerpt {
6452    fn new(
6453        id: ExcerptId,
6454        locator: Locator,
6455        buffer_id: BufferId,
6456        buffer: BufferSnapshot,
6457        range: ExcerptRange<text::Anchor>,
6458        has_trailing_newline: bool,
6459    ) -> Self {
6460        Excerpt {
6461            id,
6462            locator,
6463            max_buffer_row: range.context.end.to_point(&buffer).row,
6464            text_summary: buffer
6465                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6466            buffer_id,
6467            buffer,
6468            range,
6469            has_trailing_newline,
6470        }
6471    }
6472
6473    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6474        let content_start = self.range.context.start.to_offset(&self.buffer);
6475        let chunks_start = content_start + range.start;
6476        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6477
6478        let footer_height = if self.has_trailing_newline
6479            && range.start <= self.text_summary.len
6480            && range.end > self.text_summary.len
6481        {
6482            1
6483        } else {
6484            0
6485        };
6486
6487        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6488
6489        ExcerptChunks {
6490            excerpt_id: self.id,
6491            content_chunks,
6492            footer_height,
6493        }
6494    }
6495
6496    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6497        let content_start = self.range.context.start.to_offset(&self.buffer);
6498        let chunks_start = content_start + range.start;
6499        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6500        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6501        excerpt_chunks.footer_height = if self.has_trailing_newline
6502            && range.start <= self.text_summary.len
6503            && range.end > self.text_summary.len
6504        {
6505            1
6506        } else {
6507            0
6508        };
6509    }
6510
6511    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6512        if text_anchor
6513            .cmp(&self.range.context.start, &self.buffer)
6514            .is_lt()
6515        {
6516            self.range.context.start
6517        } else if text_anchor
6518            .cmp(&self.range.context.end, &self.buffer)
6519            .is_gt()
6520        {
6521            self.range.context.end
6522        } else {
6523            text_anchor
6524        }
6525    }
6526
6527    fn contains(&self, anchor: &Anchor) -> bool {
6528        Some(self.buffer_id) == anchor.buffer_id
6529            && self
6530                .range
6531                .context
6532                .start
6533                .cmp(&anchor.text_anchor, &self.buffer)
6534                .is_le()
6535            && self
6536                .range
6537                .context
6538                .end
6539                .cmp(&anchor.text_anchor, &self.buffer)
6540                .is_ge()
6541    }
6542
6543    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6544    fn buffer_start_offset(&self) -> usize {
6545        self.range.context.start.to_offset(&self.buffer)
6546    }
6547
6548    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6549    fn buffer_end_offset(&self) -> usize {
6550        self.buffer_start_offset() + self.text_summary.len
6551    }
6552}
6553
6554impl<'a> MultiBufferExcerpt<'a> {
6555    pub fn id(&self) -> ExcerptId {
6556        self.excerpt.id
6557    }
6558
6559    pub fn buffer_id(&self) -> BufferId {
6560        self.excerpt.buffer_id
6561    }
6562
6563    pub fn start_anchor(&self) -> Anchor {
6564        Anchor {
6565            buffer_id: Some(self.excerpt.buffer_id),
6566            excerpt_id: self.excerpt.id,
6567            text_anchor: self.excerpt.range.context.start,
6568            diff_base_anchor: None,
6569        }
6570    }
6571
6572    pub fn end_anchor(&self) -> Anchor {
6573        Anchor {
6574            buffer_id: Some(self.excerpt.buffer_id),
6575            excerpt_id: self.excerpt.id,
6576            text_anchor: self.excerpt.range.context.end,
6577            diff_base_anchor: None,
6578        }
6579    }
6580
6581    pub fn buffer(&self) -> &'a BufferSnapshot {
6582        &self.excerpt.buffer
6583    }
6584
6585    pub fn buffer_range(&self) -> Range<usize> {
6586        self.buffer_offset
6587            ..self
6588                .excerpt
6589                .range
6590                .context
6591                .end
6592                .to_offset(&self.excerpt.buffer.text)
6593    }
6594
6595    pub fn start_offset(&self) -> usize {
6596        self.offset
6597    }
6598
6599    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6600    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6601        self.map_range_to_buffer(offset..offset).start
6602    }
6603
6604    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6605    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6606        self.diff_transforms
6607            .seek(&OutputDimension(range.start), Bias::Right, &());
6608        let start = self.map_offset_to_buffer_internal(range.start);
6609        let end = if range.end > range.start {
6610            self.diff_transforms
6611                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6612            self.map_offset_to_buffer_internal(range.end)
6613        } else {
6614            start
6615        };
6616        start..end
6617    }
6618
6619    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6620        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6621        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6622            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6623        };
6624        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6625        self.buffer_offset + offset_in_excerpt
6626    }
6627
6628    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6629    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6630        self.map_range_from_buffer(buffer_offset..buffer_offset)
6631            .start
6632    }
6633
6634    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6635    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6636        if buffer_range.start < self.buffer_offset {
6637            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6638            return buffer_range;
6639        }
6640        let overshoot = buffer_range.start - self.buffer_offset;
6641        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6642        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6643        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6644            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6645            return buffer_range;
6646        }
6647        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6648        let start = self.diff_transforms.start().0 .0 + overshoot;
6649
6650        let end = if buffer_range.end > buffer_range.start {
6651            let overshoot = buffer_range.end - self.buffer_offset;
6652            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6653            self.diff_transforms
6654                .seek_forward(&excerpt_offset, Bias::Right, &());
6655            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6656            self.diff_transforms.start().0 .0 + overshoot
6657        } else {
6658            start
6659        };
6660
6661        start..end
6662    }
6663
6664    /// Returns true if the entirety of the given range is in the buffer's excerpt
6665    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6666        range.start >= self.excerpt.buffer_start_offset()
6667            && range.end <= self.excerpt.buffer_end_offset()
6668    }
6669
6670    pub fn max_buffer_row(&self) -> u32 {
6671        self.excerpt.max_buffer_row
6672    }
6673}
6674
6675impl ExcerptId {
6676    pub fn min() -> Self {
6677        Self(0)
6678    }
6679
6680    pub fn max() -> Self {
6681        Self(usize::MAX)
6682    }
6683
6684    pub fn to_proto(&self) -> u64 {
6685        self.0 as _
6686    }
6687
6688    pub fn from_proto(proto: u64) -> Self {
6689        Self(proto as _)
6690    }
6691
6692    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6693        let a = snapshot.excerpt_locator_for_id(*self);
6694        let b = snapshot.excerpt_locator_for_id(*other);
6695        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6696    }
6697}
6698
6699impl From<ExcerptId> for usize {
6700    fn from(val: ExcerptId) -> Self {
6701        val.0
6702    }
6703}
6704
6705impl fmt::Debug for Excerpt {
6706    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6707        f.debug_struct("Excerpt")
6708            .field("id", &self.id)
6709            .field("locator", &self.locator)
6710            .field("buffer_id", &self.buffer_id)
6711            .field("range", &self.range)
6712            .field("text_summary", &self.text_summary)
6713            .field("has_trailing_newline", &self.has_trailing_newline)
6714            .finish()
6715    }
6716}
6717
6718impl sum_tree::Item for Excerpt {
6719    type Summary = ExcerptSummary;
6720
6721    fn summary(&self, _cx: &()) -> Self::Summary {
6722        let mut text = self.text_summary;
6723        if self.has_trailing_newline {
6724            text += TextSummary::from("\n");
6725        }
6726        ExcerptSummary {
6727            excerpt_id: self.id,
6728            excerpt_locator: self.locator.clone(),
6729            widest_line_number: self.max_buffer_row,
6730            text,
6731        }
6732    }
6733}
6734
6735impl sum_tree::Item for ExcerptIdMapping {
6736    type Summary = ExcerptId;
6737
6738    fn summary(&self, _cx: &()) -> Self::Summary {
6739        self.id
6740    }
6741}
6742
6743impl sum_tree::KeyedItem for ExcerptIdMapping {
6744    type Key = ExcerptId;
6745
6746    fn key(&self) -> Self::Key {
6747        self.id
6748    }
6749}
6750
6751impl DiffTransform {
6752    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6753        match self {
6754            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6755            DiffTransform::BufferContent {
6756                inserted_hunk_info, ..
6757            } => *inserted_hunk_info,
6758        }
6759    }
6760}
6761
6762impl sum_tree::Item for DiffTransform {
6763    type Summary = DiffTransformSummary;
6764
6765    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6766        match self {
6767            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6768                input: *summary,
6769                output: *summary,
6770            },
6771            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6772                input: TextSummary::default(),
6773                output: *summary,
6774            },
6775        }
6776    }
6777}
6778
6779impl DiffTransformSummary {
6780    fn excerpt_len(&self) -> ExcerptOffset {
6781        ExcerptOffset::new(self.input.len)
6782    }
6783}
6784
6785impl sum_tree::Summary for DiffTransformSummary {
6786    type Context = ();
6787
6788    fn zero(_: &Self::Context) -> Self {
6789        DiffTransformSummary {
6790            input: TextSummary::default(),
6791            output: TextSummary::default(),
6792        }
6793    }
6794
6795    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6796        self.input += &summary.input;
6797        self.output += &summary.output;
6798    }
6799}
6800
6801impl sum_tree::Summary for ExcerptId {
6802    type Context = ();
6803
6804    fn zero(_cx: &()) -> Self {
6805        Default::default()
6806    }
6807
6808    fn add_summary(&mut self, other: &Self, _: &()) {
6809        *self = *other;
6810    }
6811}
6812
6813impl sum_tree::Summary for ExcerptSummary {
6814    type Context = ();
6815
6816    fn zero(_cx: &()) -> Self {
6817        Default::default()
6818    }
6819
6820    fn add_summary(&mut self, summary: &Self, _: &()) {
6821        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6822        self.excerpt_locator = summary.excerpt_locator.clone();
6823        self.text.add_summary(&summary.text, &());
6824        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6825    }
6826}
6827
6828impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6829    fn zero(_cx: &()) -> Self {
6830        Default::default()
6831    }
6832
6833    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6834        self.value += summary.text.len;
6835    }
6836}
6837
6838impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6839    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6840        Ord::cmp(&self.value, &cursor_location.text.len)
6841    }
6842}
6843
6844impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6845    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6846        Ord::cmp(&Some(self), cursor_location)
6847    }
6848}
6849
6850impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6851    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6852        Ord::cmp(self, &cursor_location.excerpt_locator)
6853    }
6854}
6855
6856impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6857    fn zero(_cx: &()) -> Self {
6858        Default::default()
6859    }
6860
6861    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6862        self.value += summary.text.lines;
6863    }
6864}
6865
6866impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6867    for ExcerptDimension<D>
6868{
6869    fn zero(_: &()) -> Self {
6870        ExcerptDimension(D::default())
6871    }
6872
6873    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6874        self.0.add_assign(&D::from_text_summary(&summary.text))
6875    }
6876}
6877
6878impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6879    fn zero(_cx: &()) -> Self {
6880        Default::default()
6881    }
6882
6883    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6884        *self = Some(&summary.excerpt_locator);
6885    }
6886}
6887
6888impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6889    fn zero(_cx: &()) -> Self {
6890        Default::default()
6891    }
6892
6893    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6894        *self = Some(summary.excerpt_id);
6895    }
6896}
6897
6898#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6899struct ExcerptDimension<T>(T);
6900
6901#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6902struct OutputDimension<T>(T);
6903
6904impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6905    fn zero(_: &()) -> Self {
6906        ExcerptOffset::new(0)
6907    }
6908
6909    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6910        self.value += summary.input.len;
6911    }
6912}
6913
6914impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6915    fn zero(_: &()) -> Self {
6916        ExcerptPoint::new(0, 0)
6917    }
6918
6919    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6920        self.value += summary.input.lines;
6921    }
6922}
6923
6924impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6925    for ExcerptDimension<D>
6926{
6927    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6928        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6929    }
6930}
6931
6932impl<D: TextDimension + Ord>
6933    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6934    for ExcerptDimension<D>
6935{
6936    fn cmp(
6937        &self,
6938        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6939        _: &(),
6940    ) -> cmp::Ordering {
6941        Ord::cmp(&self.0, &cursor_location.1 .0)
6942    }
6943}
6944
6945impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6946    fn zero(_: &()) -> Self {
6947        ExcerptDimension(D::default())
6948    }
6949
6950    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6951        self.0.add_assign(&D::from_text_summary(&summary.input))
6952    }
6953}
6954
6955impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6956    fn zero(_: &()) -> Self {
6957        OutputDimension(D::default())
6958    }
6959
6960    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6961        self.0.add_assign(&D::from_text_summary(&summary.output))
6962    }
6963}
6964
6965impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6966    fn zero(_: &()) -> Self {
6967        TextSummary::default()
6968    }
6969
6970    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6971        *self += summary.output
6972    }
6973}
6974
6975impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6976    fn zero(_: &()) -> Self {
6977        0
6978    }
6979
6980    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6981        *self += summary.output.len
6982    }
6983}
6984
6985impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6986    fn zero(_: &()) -> Self {
6987        Point::new(0, 0)
6988    }
6989
6990    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6991        *self += summary.output.lines
6992    }
6993}
6994
6995impl MultiBufferRows<'_> {
6996    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6997        self.point = Point::new(row, 0);
6998        self.cursor.seek(&self.point);
6999    }
7000}
7001
7002impl Iterator for MultiBufferRows<'_> {
7003    type Item = RowInfo;
7004
7005    fn next(&mut self) -> Option<Self::Item> {
7006        if self.is_empty && self.point.row == 0 {
7007            self.point += Point::new(1, 0);
7008            return Some(RowInfo {
7009                buffer_id: None,
7010                buffer_row: Some(0),
7011                multibuffer_row: Some(MultiBufferRow(0)),
7012                diff_status: None,
7013            });
7014        }
7015
7016        let mut region = self.cursor.region()?;
7017        while self.point >= region.range.end {
7018            self.cursor.next();
7019            if let Some(next_region) = self.cursor.region() {
7020                region = next_region;
7021            } else {
7022                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7023                    let multibuffer_row = MultiBufferRow(self.point.row);
7024                    self.point += Point::new(1, 0);
7025                    let last_excerpt = self
7026                        .cursor
7027                        .excerpts
7028                        .item()
7029                        .or(self.cursor.excerpts.prev_item())?;
7030                    let last_row = last_excerpt
7031                        .range
7032                        .context
7033                        .end
7034                        .to_point(&last_excerpt.buffer)
7035                        .row;
7036                    return Some(RowInfo {
7037                        buffer_id: Some(last_excerpt.buffer_id),
7038                        buffer_row: Some(last_row),
7039                        multibuffer_row: Some(multibuffer_row),
7040                        diff_status: None,
7041                    });
7042                } else {
7043                    return None;
7044                }
7045            };
7046        }
7047
7048        let overshoot = self.point - region.range.start;
7049        let buffer_point = region.buffer_range.start + overshoot;
7050        let result = Some(RowInfo {
7051            buffer_id: Some(region.buffer.remote_id()),
7052            buffer_row: Some(buffer_point.row),
7053            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7054            diff_status: region
7055                .diff_hunk_status
7056                .filter(|_| self.point < region.range.end),
7057        });
7058        self.point += Point::new(1, 0);
7059        result
7060    }
7061}
7062
7063impl<'a> MultiBufferChunks<'a> {
7064    pub fn offset(&self) -> usize {
7065        self.range.start
7066    }
7067
7068    pub fn seek(&mut self, range: Range<usize>) {
7069        self.diff_transforms.seek(&range.end, Bias::Right, &());
7070        let mut excerpt_end = self.diff_transforms.start().1;
7071        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7072            let overshoot = range.end - self.diff_transforms.start().0;
7073            excerpt_end.value += overshoot;
7074        }
7075
7076        self.diff_transforms.seek(&range.start, Bias::Right, &());
7077        let mut excerpt_start = self.diff_transforms.start().1;
7078        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7079            let overshoot = range.start - self.diff_transforms.start().0;
7080            excerpt_start.value += overshoot;
7081        }
7082
7083        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7084        self.buffer_chunk.take();
7085        self.range = range;
7086    }
7087
7088    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7089        self.excerpt_offset_range = new_range.clone();
7090        self.excerpts.seek(&new_range.start, Bias::Right, &());
7091        if let Some(excerpt) = self.excerpts.item() {
7092            let excerpt_start = *self.excerpts.start();
7093            if let Some(excerpt_chunks) = self
7094                .excerpt_chunks
7095                .as_mut()
7096                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7097            {
7098                excerpt.seek_chunks(
7099                    excerpt_chunks,
7100                    (self.excerpt_offset_range.start - excerpt_start).value
7101                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7102                );
7103            } else {
7104                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7105                    (self.excerpt_offset_range.start - excerpt_start).value
7106                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7107                    self.language_aware,
7108                ));
7109            }
7110        } else {
7111            self.excerpt_chunks = None;
7112        }
7113    }
7114
7115    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7116        loop {
7117            if self.excerpt_offset_range.is_empty() {
7118                return None;
7119            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7120                self.excerpt_offset_range.start.value += chunk.text.len();
7121                return Some(chunk);
7122            } else {
7123                self.excerpts.next(&());
7124                let excerpt = self.excerpts.item()?;
7125                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7126                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7127                    self.language_aware,
7128                ));
7129            }
7130        }
7131    }
7132}
7133
7134impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7135    type Item = &'a str;
7136
7137    fn next(&mut self) -> Option<Self::Item> {
7138        let mut region = self.cursor.region()?;
7139        if self.offset == region.range.start {
7140            self.cursor.prev();
7141            region = self.cursor.region()?;
7142            let start_overshoot = self.start.saturating_sub(region.range.start);
7143            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7144                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7145            ));
7146        }
7147
7148        if self.offset == region.range.end && region.has_trailing_newline {
7149            self.offset -= 1;
7150            Some("\n")
7151        } else {
7152            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7153            self.offset -= chunk.len();
7154            Some(chunk)
7155        }
7156    }
7157}
7158
7159impl<'a> Iterator for MultiBufferChunks<'a> {
7160    type Item = Chunk<'a>;
7161
7162    fn next(&mut self) -> Option<Chunk<'a>> {
7163        if self.range.start >= self.range.end {
7164            return None;
7165        }
7166        if self.range.start == self.diff_transforms.end(&()).0 {
7167            self.diff_transforms.next(&());
7168        }
7169
7170        let diff_transform_start = self.diff_transforms.start().0;
7171        let diff_transform_end = self.diff_transforms.end(&()).0;
7172        debug_assert!(self.range.start < diff_transform_end);
7173
7174        let diff_transform = self.diff_transforms.item()?;
7175        match diff_transform {
7176            DiffTransform::BufferContent { .. } => {
7177                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7178                    chunk
7179                } else {
7180                    let chunk = self.next_excerpt_chunk().unwrap();
7181                    self.buffer_chunk.insert(chunk)
7182                };
7183
7184                let chunk_end = self.range.start + chunk.text.len();
7185                let diff_transform_end = diff_transform_end.min(self.range.end);
7186
7187                if diff_transform_end < chunk_end {
7188                    let (before, after) =
7189                        chunk.text.split_at(diff_transform_end - self.range.start);
7190                    self.range.start = diff_transform_end;
7191                    chunk.text = after;
7192                    Some(Chunk {
7193                        text: before,
7194                        ..chunk.clone()
7195                    })
7196                } else {
7197                    self.range.start = chunk_end;
7198                    self.buffer_chunk.take()
7199                }
7200            }
7201            DiffTransform::DeletedHunk {
7202                buffer_id,
7203                base_text_byte_range,
7204                has_trailing_newline,
7205                ..
7206            } => {
7207                let base_text_start =
7208                    base_text_byte_range.start + self.range.start - diff_transform_start;
7209                let base_text_end =
7210                    base_text_byte_range.start + self.range.end - diff_transform_start;
7211                let base_text_end = base_text_end.min(base_text_byte_range.end);
7212
7213                let mut chunks = if let Some((_, mut chunks)) = self
7214                    .diff_base_chunks
7215                    .take()
7216                    .filter(|(id, _)| id == buffer_id)
7217                {
7218                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7219                    {
7220                        chunks.seek(base_text_start..base_text_end);
7221                    }
7222                    chunks
7223                } else {
7224                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7225                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7226                };
7227
7228                let chunk = if let Some(chunk) = chunks.next() {
7229                    self.range.start += chunk.text.len();
7230                    self.diff_base_chunks = Some((*buffer_id, chunks));
7231                    chunk
7232                } else {
7233                    debug_assert!(has_trailing_newline);
7234                    self.range.start += "\n".len();
7235                    Chunk {
7236                        text: "\n",
7237                        ..Default::default()
7238                    }
7239                };
7240                Some(chunk)
7241            }
7242        }
7243    }
7244}
7245
7246impl MultiBufferBytes<'_> {
7247    fn consume(&mut self, len: usize) {
7248        self.range.start += len;
7249        self.chunk = &self.chunk[len..];
7250
7251        if !self.range.is_empty() && self.chunk.is_empty() {
7252            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7253                self.chunk = chunk;
7254            } else if self.has_trailing_newline {
7255                self.has_trailing_newline = false;
7256                self.chunk = b"\n";
7257            } else {
7258                self.cursor.next();
7259                if let Some(region) = self.cursor.region() {
7260                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7261                        region.buffer_range.start
7262                            ..(region.buffer_range.start + self.range.end - region.range.start)
7263                                .min(region.buffer_range.end),
7264                    );
7265                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7266                    self.excerpt_bytes = Some(excerpt_bytes);
7267                    self.has_trailing_newline =
7268                        region.has_trailing_newline && self.range.end >= region.range.end;
7269                    if self.chunk.is_empty() && self.has_trailing_newline {
7270                        self.has_trailing_newline = false;
7271                        self.chunk = b"\n";
7272                    }
7273                }
7274            }
7275        }
7276    }
7277}
7278
7279impl<'a> Iterator for MultiBufferBytes<'a> {
7280    type Item = &'a [u8];
7281
7282    fn next(&mut self) -> Option<Self::Item> {
7283        let chunk = self.chunk;
7284        if chunk.is_empty() {
7285            None
7286        } else {
7287            self.consume(chunk.len());
7288            Some(chunk)
7289        }
7290    }
7291}
7292
7293impl io::Read for MultiBufferBytes<'_> {
7294    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7295        let len = cmp::min(buf.len(), self.chunk.len());
7296        buf[..len].copy_from_slice(&self.chunk[..len]);
7297        if len > 0 {
7298            self.consume(len);
7299        }
7300        Ok(len)
7301    }
7302}
7303
7304impl io::Read for ReversedMultiBufferBytes<'_> {
7305    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7306        let len = cmp::min(buf.len(), self.chunk.len());
7307        buf[..len].copy_from_slice(&self.chunk[..len]);
7308        buf[..len].reverse();
7309        if len > 0 {
7310            self.range.end -= len;
7311            self.chunk = &self.chunk[..self.chunk.len() - len];
7312            if !self.range.is_empty() && self.chunk.is_empty() {
7313                if let Some(chunk) = self.chunks.next() {
7314                    self.chunk = chunk.as_bytes();
7315                }
7316            }
7317        }
7318        Ok(len)
7319    }
7320}
7321
7322impl<'a> Iterator for ExcerptChunks<'a> {
7323    type Item = Chunk<'a>;
7324
7325    fn next(&mut self) -> Option<Self::Item> {
7326        if let Some(chunk) = self.content_chunks.next() {
7327            return Some(chunk);
7328        }
7329
7330        if self.footer_height > 0 {
7331            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7332            self.footer_height = 0;
7333            return Some(Chunk {
7334                text,
7335                ..Default::default()
7336            });
7337        }
7338
7339        None
7340    }
7341}
7342
7343impl ToOffset for Point {
7344    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7345        snapshot.point_to_offset(*self)
7346    }
7347}
7348
7349impl ToOffset for usize {
7350    #[track_caller]
7351    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7352        assert!(*self <= snapshot.len(), "offset is out of range");
7353        *self
7354    }
7355}
7356
7357impl ToOffset for OffsetUtf16 {
7358    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7359        snapshot.offset_utf16_to_offset(*self)
7360    }
7361}
7362
7363impl ToOffset for PointUtf16 {
7364    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7365        snapshot.point_utf16_to_offset(*self)
7366    }
7367}
7368
7369impl ToOffsetUtf16 for OffsetUtf16 {
7370    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7371        *self
7372    }
7373}
7374
7375impl ToOffsetUtf16 for usize {
7376    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7377        snapshot.offset_to_offset_utf16(*self)
7378    }
7379}
7380
7381impl ToPoint for usize {
7382    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7383        snapshot.offset_to_point(*self)
7384    }
7385}
7386
7387impl ToPoint for Point {
7388    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7389        *self
7390    }
7391}
7392
7393impl ToPointUtf16 for usize {
7394    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7395        snapshot.offset_to_point_utf16(*self)
7396    }
7397}
7398
7399impl ToPointUtf16 for Point {
7400    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7401        snapshot.point_to_point_utf16(*self)
7402    }
7403}
7404
7405impl ToPointUtf16 for PointUtf16 {
7406    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7407        *self
7408    }
7409}
7410
7411impl From<ExcerptId> for EntityId {
7412    fn from(id: ExcerptId) -> Self {
7413        EntityId::from(id.0 as u64)
7414    }
7415}
7416
7417pub fn build_excerpt_ranges<T>(
7418    buffer: &BufferSnapshot,
7419    ranges: &[Range<T>],
7420    context_line_count: u32,
7421) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7422where
7423    T: text::ToPoint,
7424{
7425    let max_point = buffer.max_point();
7426    let mut range_counts = Vec::new();
7427    let mut excerpt_ranges = Vec::new();
7428    let mut range_iter = ranges
7429        .iter()
7430        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7431        .peekable();
7432    while let Some(range) = range_iter.next() {
7433        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7434        let row = (range.end.row + context_line_count).min(max_point.row);
7435        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7436
7437        let mut ranges_in_excerpt = 1;
7438
7439        while let Some(next_range) = range_iter.peek() {
7440            if next_range.start.row <= excerpt_end.row + context_line_count {
7441                let row = (next_range.end.row + context_line_count).min(max_point.row);
7442                excerpt_end = Point::new(row, buffer.line_len(row));
7443
7444                ranges_in_excerpt += 1;
7445                range_iter.next();
7446            } else {
7447                break;
7448            }
7449        }
7450
7451        excerpt_ranges.push(ExcerptRange {
7452            context: excerpt_start..excerpt_end,
7453            primary: Some(range),
7454        });
7455        range_counts.push(ranges_in_excerpt);
7456    }
7457
7458    (excerpt_ranges, range_counts)
7459}