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::{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    rc::Rc,
  43    str,
  44    sync::Arc,
  45    time::{Duration, Instant},
  46};
  47use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  48use text::{
  49    locator::Locator,
  50    subscription::{Subscription, Topic},
  51    BufferId, Edit, LineIndent, TextSummary,
  52};
  53use theme::SyntaxTheme;
  54use util::post_inc;
  55
  56const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  57
  58#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  59pub struct ExcerptId(usize);
  60
  61/// One or more [`Buffers`](Buffer) being edited in a single view.
  62///
  63/// See <https://zed.dev/features#multi-buffers>
  64pub struct MultiBuffer {
  65    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  66    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  67    snapshot: RefCell<MultiBufferSnapshot>,
  68    /// Contains the state of the buffers being edited
  69    buffers: RefCell<HashMap<BufferId, BufferState>>,
  70    // only used by consumers using `set_excerpts_for_buffer`
  71    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  72    diffs: HashMap<BufferId, DiffState>,
  73    // all_diff_hunks_expanded: bool,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    history: History,
  78    title: Option<String>,
  79    capability: Capability,
  80    buffer_changed_since_sync: Rc<Cell<bool>>,
  81}
  82
  83#[derive(Clone, Debug, PartialEq, Eq)]
  84pub enum MultiOrSingleBufferOffsetRange {
  85    Single(Range<usize>),
  86    Multi(Range<usize>),
  87}
  88
  89#[derive(Clone, Debug, PartialEq, Eq)]
  90pub enum Event {
  91    ExcerptsAdded {
  92        buffer: Entity<Buffer>,
  93        predecessor: ExcerptId,
  94        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  95    },
  96    ExcerptsRemoved {
  97        ids: Vec<ExcerptId>,
  98    },
  99    ExcerptsExpanded {
 100        ids: Vec<ExcerptId>,
 101    },
 102    ExcerptsEdited {
 103        excerpt_ids: Vec<ExcerptId>,
 104        buffer_ids: Vec<BufferId>,
 105    },
 106    DiffHunksToggled,
 107    Edited {
 108        singleton_buffer_edited: bool,
 109        edited_buffer: Option<Entity<Buffer>>,
 110    },
 111    TransactionUndone {
 112        transaction_id: TransactionId,
 113    },
 114    Reloaded,
 115    ReloadNeeded,
 116
 117    LanguageChanged(BufferId),
 118    CapabilityChanged,
 119    Reparsed(BufferId),
 120    Saved,
 121    FileHandleChanged,
 122    Closed,
 123    Discarded,
 124    DirtyChanged,
 125    DiagnosticsUpdated,
 126    BufferDiffChanged,
 127}
 128
 129/// A diff hunk, representing a range of consequent lines in a multibuffer.
 130#[derive(Debug, Clone, PartialEq, Eq)]
 131pub struct MultiBufferDiffHunk {
 132    /// The row range in the multibuffer where this diff hunk appears.
 133    pub row_range: Range<MultiBufferRow>,
 134    /// The buffer ID that this hunk belongs to.
 135    pub buffer_id: BufferId,
 136    /// The range of the underlying buffer that this hunk corresponds to.
 137    pub buffer_range: Range<text::Anchor>,
 138    /// The excerpt that contains the diff hunk.
 139    pub excerpt_id: ExcerptId,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<usize>,
 142    /// Whether or not this hunk also appears in the 'secondary diff'.
 143    pub secondary_status: DiffHunkSecondaryStatus,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (0..0)
 163            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 164    }
 165}
 166
 167#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 168pub struct PathKey {
 169    namespace: &'static str,
 170    path: Arc<Path>,
 171}
 172
 173impl PathKey {
 174    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 175        Self { namespace, path }
 176    }
 177
 178    pub fn path(&self) -> &Arc<Path> {
 179        &self.path
 180    }
 181}
 182
 183pub type MultiBufferPoint = Point;
 184type ExcerptOffset = TypedOffset<Excerpt>;
 185type ExcerptPoint = TypedPoint<Excerpt>;
 186
 187#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 188#[serde(transparent)]
 189pub struct MultiBufferRow(pub u32);
 190
 191impl MultiBufferRow {
 192    pub const MIN: Self = Self(0);
 193    pub const MAX: Self = Self(u32::MAX);
 194}
 195
 196impl std::ops::Add<usize> for MultiBufferRow {
 197    type Output = Self;
 198
 199    fn add(self, rhs: usize) -> Self::Output {
 200        MultiBufferRow(self.0 + rhs as u32)
 201    }
 202}
 203
 204#[derive(Clone)]
 205struct History {
 206    next_transaction_id: TransactionId,
 207    undo_stack: Vec<Transaction>,
 208    redo_stack: Vec<Transaction>,
 209    transaction_depth: usize,
 210    group_interval: Duration,
 211}
 212
 213#[derive(Clone)]
 214struct Transaction {
 215    id: TransactionId,
 216    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 217    first_edit_at: Instant,
 218    last_edit_at: Instant,
 219    suppress_grouping: bool,
 220}
 221
 222pub trait ToOffset: 'static + fmt::Debug {
 223    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 224}
 225
 226pub trait ToOffsetUtf16: 'static + fmt::Debug {
 227    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 228}
 229
 230pub trait ToPoint: 'static + fmt::Debug {
 231    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 232}
 233
 234pub trait ToPointUtf16: 'static + fmt::Debug {
 235    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 236}
 237
 238struct BufferState {
 239    buffer: Entity<Buffer>,
 240    last_version: clock::Global,
 241    last_non_text_state_update_count: usize,
 242    excerpts: Vec<Locator>,
 243    _subscriptions: [gpui::Subscription; 2],
 244}
 245
 246struct DiffState {
 247    diff: Entity<BufferDiff>,
 248    _subscription: gpui::Subscription,
 249}
 250
 251impl DiffState {
 252    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 253        DiffState {
 254            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 255                BufferDiffEvent::DiffChanged { changed_range } => {
 256                    if let Some(changed_range) = changed_range.clone() {
 257                        this.buffer_diff_changed(diff, changed_range, cx)
 258                    }
 259                    cx.emit(Event::BufferDiffChanged);
 260                }
 261                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 262                _ => {}
 263            }),
 264            diff,
 265        }
 266    }
 267}
 268
 269/// The contents of a [`MultiBuffer`] at a single point in time.
 270#[derive(Clone, Default)]
 271pub struct MultiBufferSnapshot {
 272    singleton: bool,
 273    excerpts: SumTree<Excerpt>,
 274    excerpt_ids: SumTree<ExcerptIdMapping>,
 275    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 276    diff_transforms: SumTree<DiffTransform>,
 277    trailing_excerpt_update_count: usize,
 278    all_diff_hunks_expanded: bool,
 279    non_text_state_update_count: usize,
 280    edit_count: usize,
 281    is_dirty: bool,
 282    has_deleted_file: bool,
 283    has_conflict: bool,
 284    show_headers: bool,
 285}
 286
 287#[derive(Debug, Clone)]
 288enum DiffTransform {
 289    BufferContent {
 290        summary: TextSummary,
 291        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 292    },
 293    DeletedHunk {
 294        summary: TextSummary,
 295        buffer_id: BufferId,
 296        hunk_info: DiffTransformHunkInfo,
 297        base_text_byte_range: Range<usize>,
 298        has_trailing_newline: bool,
 299    },
 300}
 301
 302#[derive(Clone, Copy, Debug)]
 303struct DiffTransformHunkInfo {
 304    excerpt_id: ExcerptId,
 305    hunk_start_anchor: text::Anchor,
 306    hunk_secondary_status: DiffHunkSecondaryStatus,
 307}
 308
 309impl Eq for DiffTransformHunkInfo {}
 310
 311impl PartialEq for DiffTransformHunkInfo {
 312    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 313        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 314    }
 315}
 316
 317impl std::hash::Hash for DiffTransformHunkInfo {
 318    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 319        self.excerpt_id.hash(state);
 320        self.hunk_start_anchor.hash(state);
 321    }
 322}
 323
 324#[derive(Clone)]
 325pub struct ExcerptInfo {
 326    pub id: ExcerptId,
 327    pub buffer: BufferSnapshot,
 328    pub buffer_id: BufferId,
 329    pub range: ExcerptRange<text::Anchor>,
 330    pub end_row: MultiBufferRow,
 331}
 332
 333impl std::fmt::Debug for ExcerptInfo {
 334    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 335        f.debug_struct(type_name::<Self>())
 336            .field("id", &self.id)
 337            .field("buffer_id", &self.buffer_id)
 338            .field("path", &self.buffer.file().map(|f| f.path()))
 339            .field("range", &self.range)
 340            .finish()
 341    }
 342}
 343
 344/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 345#[derive(Debug)]
 346pub struct ExcerptBoundary {
 347    pub prev: Option<ExcerptInfo>,
 348    pub next: Option<ExcerptInfo>,
 349    /// The row in the `MultiBuffer` where the boundary is located
 350    pub row: MultiBufferRow,
 351}
 352
 353impl ExcerptBoundary {
 354    pub fn starts_new_buffer(&self) -> bool {
 355        match (self.prev.as_ref(), self.next.as_ref()) {
 356            (None, _) => true,
 357            (Some(_), None) => false,
 358            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 359        }
 360    }
 361}
 362
 363#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 364pub struct RowInfo {
 365    pub buffer_id: Option<BufferId>,
 366    pub buffer_row: Option<u32>,
 367    pub multibuffer_row: Option<MultiBufferRow>,
 368    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 369}
 370
 371/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 372#[derive(Clone)]
 373struct Excerpt {
 374    /// The unique identifier for this excerpt
 375    id: ExcerptId,
 376    /// The location of the excerpt in the [`MultiBuffer`]
 377    locator: Locator,
 378    /// The buffer being excerpted
 379    buffer_id: BufferId,
 380    /// A snapshot of the buffer being excerpted
 381    buffer: BufferSnapshot,
 382    /// The range of the buffer to be shown in the excerpt
 383    range: ExcerptRange<text::Anchor>,
 384    /// The last row in the excerpted slice of the buffer
 385    max_buffer_row: BufferRow,
 386    /// A summary of the text in the excerpt
 387    text_summary: TextSummary,
 388    has_trailing_newline: bool,
 389}
 390
 391/// A public view into an `Excerpt` in a [`MultiBuffer`].
 392///
 393/// Contains methods for getting the [`Buffer`] of the excerpt,
 394/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 395#[derive(Clone)]
 396pub struct MultiBufferExcerpt<'a> {
 397    excerpt: &'a Excerpt,
 398    diff_transforms:
 399        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 400    offset: usize,
 401    excerpt_offset: ExcerptDimension<usize>,
 402    buffer_offset: usize,
 403}
 404
 405#[derive(Clone, Debug)]
 406struct ExcerptIdMapping {
 407    id: ExcerptId,
 408    locator: Locator,
 409}
 410
 411/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 412/// These ranges are relative to the buffer itself
 413#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 414pub struct ExcerptRange<T> {
 415    /// The full range of text to be shown in the excerpt.
 416    pub context: Range<T>,
 417    /// The primary range of text to be highlighted in the excerpt.
 418    /// In a multi-buffer search, this would be the text that matched the search
 419    pub primary: Option<Range<T>>,
 420}
 421
 422#[derive(Clone, Debug, Default)]
 423pub struct ExcerptSummary {
 424    excerpt_id: ExcerptId,
 425    /// The location of the last [`Excerpt`] being summarized
 426    excerpt_locator: Locator,
 427    widest_line_number: u32,
 428    text: TextSummary,
 429}
 430
 431#[derive(Debug, Clone)]
 432pub struct DiffTransformSummary {
 433    input: TextSummary,
 434    output: TextSummary,
 435}
 436
 437#[derive(Clone)]
 438pub struct MultiBufferRows<'a> {
 439    point: Point,
 440    is_empty: bool,
 441    cursor: MultiBufferCursor<'a, Point>,
 442}
 443
 444pub struct MultiBufferChunks<'a> {
 445    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 446    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 447    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 448    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 449    buffer_chunk: Option<Chunk<'a>>,
 450    range: Range<usize>,
 451    excerpt_offset_range: Range<ExcerptOffset>,
 452    excerpt_chunks: Option<ExcerptChunks<'a>>,
 453    language_aware: bool,
 454}
 455
 456pub struct ReversedMultiBufferChunks<'a> {
 457    cursor: MultiBufferCursor<'a, usize>,
 458    current_chunks: Option<rope::Chunks<'a>>,
 459    start: usize,
 460    offset: usize,
 461}
 462
 463pub struct MultiBufferBytes<'a> {
 464    range: Range<usize>,
 465    cursor: MultiBufferCursor<'a, usize>,
 466    excerpt_bytes: Option<text::Bytes<'a>>,
 467    has_trailing_newline: bool,
 468    chunk: &'a [u8],
 469}
 470
 471pub struct ReversedMultiBufferBytes<'a> {
 472    range: Range<usize>,
 473    chunks: ReversedMultiBufferChunks<'a>,
 474    chunk: &'a [u8],
 475}
 476
 477#[derive(Clone)]
 478struct MultiBufferCursor<'a, D: TextDimension> {
 479    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 480    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 481    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 482    cached_region: Option<MultiBufferRegion<'a, D>>,
 483}
 484
 485#[derive(Clone)]
 486struct MultiBufferRegion<'a, D: TextDimension> {
 487    buffer: &'a BufferSnapshot,
 488    is_main_buffer: bool,
 489    diff_hunk_status: Option<DiffHunkStatus>,
 490    excerpt: &'a Excerpt,
 491    buffer_range: Range<D>,
 492    range: Range<D>,
 493    has_trailing_newline: bool,
 494}
 495
 496struct ExcerptChunks<'a> {
 497    excerpt_id: ExcerptId,
 498    content_chunks: BufferChunks<'a>,
 499    footer_height: usize,
 500}
 501
 502#[derive(Debug)]
 503struct BufferEdit {
 504    range: Range<usize>,
 505    new_text: Arc<str>,
 506    is_insertion: bool,
 507    original_indent_column: Option<u32>,
 508    excerpt_id: ExcerptId,
 509}
 510
 511#[derive(Clone, Copy, Debug, PartialEq)]
 512enum DiffChangeKind {
 513    BufferEdited,
 514    DiffUpdated { base_changed: bool },
 515    ExpandOrCollapseHunks { expand: bool },
 516}
 517
 518#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 519pub enum ExpandExcerptDirection {
 520    Up,
 521    Down,
 522    UpAndDown,
 523}
 524
 525impl ExpandExcerptDirection {
 526    pub fn should_expand_up(&self) -> bool {
 527        match self {
 528            ExpandExcerptDirection::Up => true,
 529            ExpandExcerptDirection::Down => false,
 530            ExpandExcerptDirection::UpAndDown => true,
 531        }
 532    }
 533
 534    pub fn should_expand_down(&self) -> bool {
 535        match self {
 536            ExpandExcerptDirection::Up => false,
 537            ExpandExcerptDirection::Down => true,
 538            ExpandExcerptDirection::UpAndDown => true,
 539        }
 540    }
 541}
 542
 543#[derive(Clone, Debug, PartialEq)]
 544pub struct IndentGuide {
 545    pub buffer_id: BufferId,
 546    pub start_row: MultiBufferRow,
 547    pub end_row: MultiBufferRow,
 548    pub depth: u32,
 549    pub tab_size: u32,
 550    pub settings: IndentGuideSettings,
 551}
 552
 553impl IndentGuide {
 554    pub fn indent_level(&self) -> u32 {
 555        self.depth * self.tab_size
 556    }
 557}
 558
 559impl MultiBuffer {
 560    pub fn new(capability: Capability) -> Self {
 561        Self {
 562            snapshot: RefCell::new(MultiBufferSnapshot {
 563                show_headers: true,
 564                ..MultiBufferSnapshot::default()
 565            }),
 566            buffers: RefCell::default(),
 567            diffs: HashMap::default(),
 568            subscriptions: Topic::default(),
 569            singleton: false,
 570            capability,
 571            title: None,
 572            buffers_by_path: Default::default(),
 573            buffer_changed_since_sync: Default::default(),
 574            history: History {
 575                next_transaction_id: clock::Lamport::default(),
 576                undo_stack: Vec::new(),
 577                redo_stack: Vec::new(),
 578                transaction_depth: 0,
 579                group_interval: Duration::from_millis(300),
 580            },
 581        }
 582    }
 583
 584    pub fn without_headers(capability: Capability) -> Self {
 585        Self {
 586            snapshot: Default::default(),
 587            buffers: Default::default(),
 588            buffers_by_path: Default::default(),
 589            diffs: HashMap::default(),
 590            subscriptions: Default::default(),
 591            singleton: false,
 592            capability,
 593            buffer_changed_since_sync: Default::default(),
 594            history: History {
 595                next_transaction_id: Default::default(),
 596                undo_stack: Default::default(),
 597                redo_stack: Default::default(),
 598                transaction_depth: 0,
 599                group_interval: Duration::from_millis(300),
 600            },
 601            title: Default::default(),
 602        }
 603    }
 604
 605    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 606        let mut buffers = HashMap::default();
 607        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 608        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 609            buffer_state.buffer.update(new_cx, |buffer, _| {
 610                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 611            });
 612            buffers.insert(
 613                *buffer_id,
 614                BufferState {
 615                    buffer: buffer_state.buffer.clone(),
 616                    last_version: buffer_state.last_version.clone(),
 617                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 618                    excerpts: buffer_state.excerpts.clone(),
 619                    _subscriptions: [
 620                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 621                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 622                    ],
 623                },
 624            );
 625        }
 626        let mut diff_bases = HashMap::default();
 627        for (buffer_id, diff) in self.diffs.iter() {
 628            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 629        }
 630        Self {
 631            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 632            buffers: RefCell::new(buffers),
 633            buffers_by_path: Default::default(),
 634            diffs: diff_bases,
 635            subscriptions: Default::default(),
 636            singleton: self.singleton,
 637            capability: self.capability,
 638            history: self.history.clone(),
 639            title: self.title.clone(),
 640            buffer_changed_since_sync,
 641        }
 642    }
 643
 644    pub fn with_title(mut self, title: String) -> Self {
 645        self.title = Some(title);
 646        self
 647    }
 648
 649    pub fn read_only(&self) -> bool {
 650        self.capability == Capability::ReadOnly
 651    }
 652
 653    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 654        let mut this = Self::new(buffer.read(cx).capability());
 655        this.singleton = true;
 656        this.push_excerpts(
 657            buffer,
 658            [ExcerptRange {
 659                context: text::Anchor::MIN..text::Anchor::MAX,
 660                primary: None,
 661            }],
 662            cx,
 663        );
 664        this.snapshot.borrow_mut().singleton = true;
 665        this
 666    }
 667
 668    /// Returns an up-to-date snapshot of the MultiBuffer.
 669    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 670        self.sync(cx);
 671        self.snapshot.borrow().clone()
 672    }
 673
 674    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 675        self.sync(cx);
 676        self.snapshot.borrow()
 677    }
 678
 679    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 680        if self.singleton {
 681            return Some(
 682                self.buffers
 683                    .borrow()
 684                    .values()
 685                    .next()
 686                    .unwrap()
 687                    .buffer
 688                    .clone(),
 689            );
 690        } else {
 691            None
 692        }
 693    }
 694
 695    pub fn is_singleton(&self) -> bool {
 696        self.singleton
 697    }
 698
 699    pub fn subscribe(&mut self) -> Subscription {
 700        self.subscriptions.subscribe()
 701    }
 702
 703    pub fn is_dirty(&self, cx: &App) -> bool {
 704        self.read(cx).is_dirty()
 705    }
 706
 707    pub fn has_deleted_file(&self, cx: &App) -> bool {
 708        self.read(cx).has_deleted_file()
 709    }
 710
 711    pub fn has_conflict(&self, cx: &App) -> bool {
 712        self.read(cx).has_conflict()
 713    }
 714
 715    // The `is_empty` signature doesn't match what clippy expects
 716    #[allow(clippy::len_without_is_empty)]
 717    pub fn len(&self, cx: &App) -> usize {
 718        self.read(cx).len()
 719    }
 720
 721    pub fn is_empty(&self) -> bool {
 722        self.buffers.borrow().is_empty()
 723    }
 724
 725    pub fn symbols_containing<T: ToOffset>(
 726        &self,
 727        offset: T,
 728        theme: Option<&SyntaxTheme>,
 729        cx: &App,
 730    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 731        self.read(cx).symbols_containing(offset, theme)
 732    }
 733
 734    pub fn edit<I, S, T>(
 735        &self,
 736        edits: I,
 737        autoindent_mode: Option<AutoindentMode>,
 738        cx: &mut Context<Self>,
 739    ) where
 740        I: IntoIterator<Item = (Range<S>, T)>,
 741        S: ToOffset,
 742        T: Into<Arc<str>>,
 743    {
 744        let snapshot = self.read(cx);
 745        let edits = edits
 746            .into_iter()
 747            .map(|(range, new_text)| {
 748                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 749                if range.start > range.end {
 750                    mem::swap(&mut range.start, &mut range.end);
 751                }
 752                (range, new_text.into())
 753            })
 754            .collect::<Vec<_>>();
 755
 756        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 757
 758        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 759        fn edit_internal(
 760            this: &MultiBuffer,
 761            snapshot: Ref<MultiBufferSnapshot>,
 762            edits: Vec<(Range<usize>, Arc<str>)>,
 763            mut autoindent_mode: Option<AutoindentMode>,
 764            cx: &mut Context<MultiBuffer>,
 765        ) {
 766            if this.read_only() || this.buffers.borrow().is_empty() {
 767                return;
 768            }
 769
 770            let original_indent_columns = match &mut autoindent_mode {
 771                Some(AutoindentMode::Block {
 772                    original_indent_columns,
 773                }) => mem::take(original_indent_columns),
 774                _ => Default::default(),
 775            };
 776
 777            let (buffer_edits, edited_excerpt_ids) =
 778                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 779            drop(snapshot);
 780
 781            let mut buffer_ids = Vec::new();
 782            for (buffer_id, mut edits) in buffer_edits {
 783                buffer_ids.push(buffer_id);
 784                edits.sort_by_key(|edit| edit.range.start);
 785                this.buffers.borrow()[&buffer_id]
 786                    .buffer
 787                    .update(cx, |buffer, cx| {
 788                        let mut edits = edits.into_iter().peekable();
 789                        let mut insertions = Vec::new();
 790                        let mut original_indent_columns = Vec::new();
 791                        let mut deletions = Vec::new();
 792                        let empty_str: Arc<str> = Arc::default();
 793                        while let Some(BufferEdit {
 794                            mut range,
 795                            mut new_text,
 796                            mut is_insertion,
 797                            original_indent_column,
 798                            excerpt_id,
 799                        }) = edits.next()
 800                        {
 801                            while let Some(BufferEdit {
 802                                range: next_range,
 803                                is_insertion: next_is_insertion,
 804                                new_text: next_new_text,
 805                                excerpt_id: next_excerpt_id,
 806                                ..
 807                            }) = edits.peek()
 808                            {
 809                                if range.end >= next_range.start {
 810                                    range.end = cmp::max(next_range.end, range.end);
 811                                    is_insertion |= *next_is_insertion;
 812                                    if excerpt_id == *next_excerpt_id {
 813                                        new_text = format!("{new_text}{next_new_text}").into();
 814                                    }
 815                                    edits.next();
 816                                } else {
 817                                    break;
 818                                }
 819                            }
 820
 821                            if is_insertion {
 822                                original_indent_columns.push(original_indent_column);
 823                                insertions.push((
 824                                    buffer.anchor_before(range.start)
 825                                        ..buffer.anchor_before(range.end),
 826                                    new_text.clone(),
 827                                ));
 828                            } else if !range.is_empty() {
 829                                deletions.push((
 830                                    buffer.anchor_before(range.start)
 831                                        ..buffer.anchor_before(range.end),
 832                                    empty_str.clone(),
 833                                ));
 834                            }
 835                        }
 836
 837                        let deletion_autoindent_mode =
 838                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 839                                Some(AutoindentMode::Block {
 840                                    original_indent_columns: Default::default(),
 841                                })
 842                            } else {
 843                                autoindent_mode.clone()
 844                            };
 845                        let insertion_autoindent_mode =
 846                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 847                                Some(AutoindentMode::Block {
 848                                    original_indent_columns,
 849                                })
 850                            } else {
 851                                autoindent_mode.clone()
 852                            };
 853
 854                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 855                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 856                    })
 857            }
 858
 859            cx.emit(Event::ExcerptsEdited {
 860                excerpt_ids: edited_excerpt_ids,
 861                buffer_ids,
 862            });
 863        }
 864    }
 865
 866    fn convert_edits_to_buffer_edits(
 867        &self,
 868        edits: Vec<(Range<usize>, Arc<str>)>,
 869        snapshot: &MultiBufferSnapshot,
 870        original_indent_columns: &[Option<u32>],
 871    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 872        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 873        let mut edited_excerpt_ids = Vec::new();
 874        let mut cursor = snapshot.cursor::<usize>();
 875        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 876            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 877
 878            cursor.seek(&range.start);
 879            let mut start_region = cursor.region().expect("start offset out of bounds");
 880            if !start_region.is_main_buffer {
 881                cursor.next();
 882                if let Some(region) = cursor.region() {
 883                    start_region = region;
 884                } else {
 885                    continue;
 886                }
 887            }
 888
 889            if range.end < start_region.range.start {
 890                continue;
 891            }
 892
 893            if range.end > start_region.range.end {
 894                cursor.seek_forward(&range.end);
 895            }
 896            let mut end_region = cursor.region().expect("end offset out of bounds");
 897            if !end_region.is_main_buffer {
 898                cursor.prev();
 899                if let Some(region) = cursor.region() {
 900                    end_region = region;
 901                } else {
 902                    continue;
 903                }
 904            }
 905
 906            if range.start > end_region.range.end {
 907                continue;
 908            }
 909
 910            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 911            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 912            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 913                .min(start_region.buffer_range.end);
 914            let buffer_end =
 915                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 916
 917            if start_region.excerpt.id == end_region.excerpt.id {
 918                if start_region.is_main_buffer {
 919                    edited_excerpt_ids.push(start_region.excerpt.id);
 920                    buffer_edits
 921                        .entry(start_region.buffer.remote_id())
 922                        .or_default()
 923                        .push(BufferEdit {
 924                            range: buffer_start..buffer_end,
 925                            new_text,
 926                            is_insertion: true,
 927                            original_indent_column,
 928                            excerpt_id: start_region.excerpt.id,
 929                        });
 930                }
 931            } else {
 932                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 933                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 934                if start_region.is_main_buffer {
 935                    edited_excerpt_ids.push(start_region.excerpt.id);
 936                    buffer_edits
 937                        .entry(start_region.buffer.remote_id())
 938                        .or_default()
 939                        .push(BufferEdit {
 940                            range: start_excerpt_range,
 941                            new_text: new_text.clone(),
 942                            is_insertion: true,
 943                            original_indent_column,
 944                            excerpt_id: start_region.excerpt.id,
 945                        });
 946                }
 947                if end_region.is_main_buffer {
 948                    edited_excerpt_ids.push(end_region.excerpt.id);
 949                    buffer_edits
 950                        .entry(end_region.buffer.remote_id())
 951                        .or_default()
 952                        .push(BufferEdit {
 953                            range: end_excerpt_range,
 954                            new_text: new_text.clone(),
 955                            is_insertion: false,
 956                            original_indent_column,
 957                            excerpt_id: end_region.excerpt.id,
 958                        });
 959                }
 960
 961                cursor.seek(&range.start);
 962                cursor.next_excerpt();
 963                while let Some(region) = cursor.region() {
 964                    if region.excerpt.id == end_region.excerpt.id {
 965                        break;
 966                    }
 967                    if region.is_main_buffer {
 968                        edited_excerpt_ids.push(region.excerpt.id);
 969                        buffer_edits
 970                            .entry(region.buffer.remote_id())
 971                            .or_default()
 972                            .push(BufferEdit {
 973                                range: region.buffer_range,
 974                                new_text: new_text.clone(),
 975                                is_insertion: false,
 976                                original_indent_column,
 977                                excerpt_id: region.excerpt.id,
 978                            });
 979                    }
 980                    cursor.next_excerpt();
 981                }
 982            }
 983        }
 984        (buffer_edits, edited_excerpt_ids)
 985    }
 986
 987    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 988    where
 989        I: IntoIterator<Item = Range<S>>,
 990        S: ToOffset,
 991    {
 992        let snapshot = self.read(cx);
 993        let empty = Arc::<str>::from("");
 994        let edits = ranges
 995            .into_iter()
 996            .map(|range| {
 997                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 998                if range.start > range.end {
 999                    mem::swap(&mut range.start, &mut range.end);
1000                }
1001                (range, empty.clone())
1002            })
1003            .collect::<Vec<_>>();
1004
1005        return autoindent_ranges_internal(self, snapshot, edits, cx);
1006
1007        fn autoindent_ranges_internal(
1008            this: &MultiBuffer,
1009            snapshot: Ref<MultiBufferSnapshot>,
1010            edits: Vec<(Range<usize>, Arc<str>)>,
1011            cx: &mut Context<MultiBuffer>,
1012        ) {
1013            if this.read_only() || this.buffers.borrow().is_empty() {
1014                return;
1015            }
1016
1017            let (buffer_edits, edited_excerpt_ids) =
1018                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1019            drop(snapshot);
1020
1021            let mut buffer_ids = Vec::new();
1022            for (buffer_id, mut edits) in buffer_edits {
1023                buffer_ids.push(buffer_id);
1024                edits.sort_unstable_by_key(|edit| edit.range.start);
1025
1026                let mut ranges: Vec<Range<usize>> = Vec::new();
1027                for edit in edits {
1028                    if let Some(last_range) = ranges.last_mut() {
1029                        if edit.range.start <= last_range.end {
1030                            last_range.end = last_range.end.max(edit.range.end);
1031                            continue;
1032                        }
1033                    }
1034                    ranges.push(edit.range);
1035                }
1036
1037                this.buffers.borrow()[&buffer_id]
1038                    .buffer
1039                    .update(cx, |buffer, cx| {
1040                        buffer.autoindent_ranges(ranges, cx);
1041                    })
1042            }
1043
1044            cx.emit(Event::ExcerptsEdited {
1045                excerpt_ids: edited_excerpt_ids,
1046                buffer_ids,
1047            });
1048        }
1049    }
1050
1051    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1052    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1053    // Panics if the given position is invalid.
1054    pub fn insert_empty_line(
1055        &mut self,
1056        position: impl ToPoint,
1057        space_above: bool,
1058        space_below: bool,
1059        cx: &mut Context<Self>,
1060    ) -> Point {
1061        let multibuffer_point = position.to_point(&self.read(cx));
1062        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1063        self.start_transaction(cx);
1064        let empty_line_start = buffer.update(cx, |buffer, cx| {
1065            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1066        });
1067        self.end_transaction(cx);
1068        multibuffer_point + (empty_line_start - buffer_point)
1069    }
1070
1071    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1072        self.start_transaction_at(Instant::now(), cx)
1073    }
1074
1075    pub fn start_transaction_at(
1076        &mut self,
1077        now: Instant,
1078        cx: &mut Context<Self>,
1079    ) -> Option<TransactionId> {
1080        if let Some(buffer) = self.as_singleton() {
1081            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1082        }
1083
1084        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1085            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1086        }
1087        self.history.start_transaction(now)
1088    }
1089
1090    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1091        self.end_transaction_at(Instant::now(), cx)
1092    }
1093
1094    pub fn end_transaction_at(
1095        &mut self,
1096        now: Instant,
1097        cx: &mut Context<Self>,
1098    ) -> Option<TransactionId> {
1099        if let Some(buffer) = self.as_singleton() {
1100            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1101        }
1102
1103        let mut buffer_transactions = HashMap::default();
1104        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1105            if let Some(transaction_id) =
1106                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1107            {
1108                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1109            }
1110        }
1111
1112        if self.history.end_transaction(now, buffer_transactions) {
1113            let transaction_id = self.history.group().unwrap();
1114            Some(transaction_id)
1115        } else {
1116            None
1117        }
1118    }
1119
1120    pub fn edited_ranges_for_transaction<D>(
1121        &self,
1122        transaction_id: TransactionId,
1123        cx: &App,
1124    ) -> Vec<Range<D>>
1125    where
1126        D: TextDimension + Ord + Sub<D, Output = D>,
1127    {
1128        let Some(transaction) = self.history.transaction(transaction_id) else {
1129            return Vec::new();
1130        };
1131
1132        let mut ranges = Vec::new();
1133        let snapshot = self.read(cx);
1134        let buffers = self.buffers.borrow();
1135        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1136
1137        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1138            let Some(buffer_state) = buffers.get(buffer_id) else {
1139                continue;
1140            };
1141
1142            let buffer = buffer_state.buffer.read(cx);
1143            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1144                for excerpt_id in &buffer_state.excerpts {
1145                    cursor.seek(excerpt_id, Bias::Left, &());
1146                    if let Some(excerpt) = cursor.item() {
1147                        if excerpt.locator == *excerpt_id {
1148                            let excerpt_buffer_start =
1149                                excerpt.range.context.start.summary::<D>(buffer);
1150                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1151                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1152                            if excerpt_range.contains(&range.start)
1153                                && excerpt_range.contains(&range.end)
1154                            {
1155                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1156
1157                                let mut start = excerpt_start;
1158                                start.add_assign(&(range.start - excerpt_buffer_start));
1159                                let mut end = excerpt_start;
1160                                end.add_assign(&(range.end - excerpt_buffer_start));
1161
1162                                ranges.push(start..end);
1163                                break;
1164                            }
1165                        }
1166                    }
1167                }
1168            }
1169        }
1170
1171        ranges.sort_by_key(|range| range.start);
1172        ranges
1173    }
1174
1175    pub fn merge_transactions(
1176        &mut self,
1177        transaction: TransactionId,
1178        destination: TransactionId,
1179        cx: &mut Context<Self>,
1180    ) {
1181        if let Some(buffer) = self.as_singleton() {
1182            buffer.update(cx, |buffer, _| {
1183                buffer.merge_transactions(transaction, destination)
1184            });
1185        } else if let Some(transaction) = self.history.forget(transaction) {
1186            if let Some(destination) = self.history.transaction_mut(destination) {
1187                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1188                    if let Some(destination_buffer_transaction_id) =
1189                        destination.buffer_transactions.get(&buffer_id)
1190                    {
1191                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1192                            state.buffer.update(cx, |buffer, _| {
1193                                buffer.merge_transactions(
1194                                    buffer_transaction_id,
1195                                    *destination_buffer_transaction_id,
1196                                )
1197                            });
1198                        }
1199                    } else {
1200                        destination
1201                            .buffer_transactions
1202                            .insert(buffer_id, buffer_transaction_id);
1203                    }
1204                }
1205            }
1206        }
1207    }
1208
1209    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1210        self.history.finalize_last_transaction();
1211        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1212            buffer.update(cx, |buffer, _| {
1213                buffer.finalize_last_transaction();
1214            });
1215        }
1216    }
1217
1218    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1219    where
1220        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1221    {
1222        self.history
1223            .push_transaction(buffer_transactions, Instant::now(), cx);
1224        self.history.finalize_last_transaction();
1225    }
1226
1227    pub fn group_until_transaction(
1228        &mut self,
1229        transaction_id: TransactionId,
1230        cx: &mut Context<Self>,
1231    ) {
1232        if let Some(buffer) = self.as_singleton() {
1233            buffer.update(cx, |buffer, _| {
1234                buffer.group_until_transaction(transaction_id)
1235            });
1236        } else {
1237            self.history.group_until(transaction_id);
1238        }
1239    }
1240
1241    pub fn set_active_selections(
1242        &self,
1243        selections: &[Selection<Anchor>],
1244        line_mode: bool,
1245        cursor_shape: CursorShape,
1246        cx: &mut Context<Self>,
1247    ) {
1248        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1249            Default::default();
1250        let snapshot = self.read(cx);
1251        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1252        for selection in selections {
1253            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1254            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1255
1256            cursor.seek(&Some(start_locator), Bias::Left, &());
1257            while let Some(excerpt) = cursor.item() {
1258                if excerpt.locator > *end_locator {
1259                    break;
1260                }
1261
1262                let mut start = excerpt.range.context.start;
1263                let mut end = excerpt.range.context.end;
1264                if excerpt.id == selection.start.excerpt_id {
1265                    start = selection.start.text_anchor;
1266                }
1267                if excerpt.id == selection.end.excerpt_id {
1268                    end = selection.end.text_anchor;
1269                }
1270                selections_by_buffer
1271                    .entry(excerpt.buffer_id)
1272                    .or_default()
1273                    .push(Selection {
1274                        id: selection.id,
1275                        start,
1276                        end,
1277                        reversed: selection.reversed,
1278                        goal: selection.goal,
1279                    });
1280
1281                cursor.next(&());
1282            }
1283        }
1284
1285        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1286            if !selections_by_buffer.contains_key(buffer_id) {
1287                buffer_state
1288                    .buffer
1289                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1290            }
1291        }
1292
1293        for (buffer_id, mut selections) in selections_by_buffer {
1294            self.buffers.borrow()[&buffer_id]
1295                .buffer
1296                .update(cx, |buffer, cx| {
1297                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1298                    let mut selections = selections.into_iter().peekable();
1299                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1300                        let mut selection = selections.next()?;
1301                        while let Some(next_selection) = selections.peek() {
1302                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1303                                let next_selection = selections.next().unwrap();
1304                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1305                                    selection.end = next_selection.end;
1306                                }
1307                            } else {
1308                                break;
1309                            }
1310                        }
1311                        Some(selection)
1312                    }));
1313                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1314                });
1315        }
1316    }
1317
1318    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1319        for buffer in self.buffers.borrow().values() {
1320            buffer
1321                .buffer
1322                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1323        }
1324    }
1325
1326    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1327        let mut transaction_id = None;
1328        if let Some(buffer) = self.as_singleton() {
1329            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1330        } else {
1331            while let Some(transaction) = self.history.pop_undo() {
1332                let mut undone = false;
1333                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1334                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1335                        undone |= buffer.update(cx, |buffer, cx| {
1336                            let undo_to = *buffer_transaction_id;
1337                            if let Some(entry) = buffer.peek_undo_stack() {
1338                                *buffer_transaction_id = entry.transaction_id();
1339                            }
1340                            buffer.undo_to_transaction(undo_to, cx)
1341                        });
1342                    }
1343                }
1344
1345                if undone {
1346                    transaction_id = Some(transaction.id);
1347                    break;
1348                }
1349            }
1350        }
1351
1352        if let Some(transaction_id) = transaction_id {
1353            cx.emit(Event::TransactionUndone { transaction_id });
1354        }
1355
1356        transaction_id
1357    }
1358
1359    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1360        if let Some(buffer) = self.as_singleton() {
1361            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1362        }
1363
1364        while let Some(transaction) = self.history.pop_redo() {
1365            let mut redone = false;
1366            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1367                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1368                    redone |= buffer.update(cx, |buffer, cx| {
1369                        let redo_to = *buffer_transaction_id;
1370                        if let Some(entry) = buffer.peek_redo_stack() {
1371                            *buffer_transaction_id = entry.transaction_id();
1372                        }
1373                        buffer.redo_to_transaction(redo_to, cx)
1374                    });
1375                }
1376            }
1377
1378            if redone {
1379                return Some(transaction.id);
1380            }
1381        }
1382
1383        None
1384    }
1385
1386    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1387        if let Some(buffer) = self.as_singleton() {
1388            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1389        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1390            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1391                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1392                    buffer.update(cx, |buffer, cx| {
1393                        buffer.undo_transaction(*transaction_id, cx)
1394                    });
1395                }
1396            }
1397        }
1398    }
1399
1400    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1401        if let Some(buffer) = self.as_singleton() {
1402            buffer.update(cx, |buffer, _| {
1403                buffer.forget_transaction(transaction_id);
1404            });
1405        } else if let Some(transaction) = self.history.forget(transaction_id) {
1406            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1407                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1408                    state.buffer.update(cx, |buffer, _| {
1409                        buffer.forget_transaction(buffer_transaction_id);
1410                    });
1411                }
1412            }
1413        }
1414    }
1415
1416    pub fn push_excerpts<O>(
1417        &mut self,
1418        buffer: Entity<Buffer>,
1419        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1420        cx: &mut Context<Self>,
1421    ) -> Vec<ExcerptId>
1422    where
1423        O: text::ToOffset,
1424    {
1425        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1426    }
1427
1428    pub fn push_excerpts_with_context_lines<O>(
1429        &mut self,
1430        buffer: Entity<Buffer>,
1431        ranges: Vec<Range<O>>,
1432        context_line_count: u32,
1433        cx: &mut Context<Self>,
1434    ) -> Vec<Range<Anchor>>
1435    where
1436        O: text::ToPoint + text::ToOffset,
1437    {
1438        let buffer_id = buffer.read(cx).remote_id();
1439        let buffer_snapshot = buffer.read(cx).snapshot();
1440        let (excerpt_ranges, range_counts) =
1441            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1442
1443        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1444
1445        let mut anchor_ranges = Vec::new();
1446        let mut ranges = ranges.into_iter();
1447        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1448            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1449                let start = Anchor {
1450                    buffer_id: Some(buffer_id),
1451                    excerpt_id,
1452                    text_anchor: buffer_snapshot.anchor_after(range.start),
1453                    diff_base_anchor: None,
1454                };
1455                let end = Anchor {
1456                    buffer_id: Some(buffer_id),
1457                    excerpt_id,
1458                    text_anchor: buffer_snapshot.anchor_after(range.end),
1459                    diff_base_anchor: None,
1460                };
1461                start..end
1462            }))
1463        }
1464        anchor_ranges
1465    }
1466
1467    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1468        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1469        let snapshot = self.snapshot(cx);
1470        let excerpt = snapshot.excerpt(*excerpt_id)?;
1471        Some(Anchor::in_buffer(
1472            *excerpt_id,
1473            excerpt.buffer_id,
1474            excerpt.range.context.start,
1475        ))
1476    }
1477
1478    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1479        self.buffers_by_path.keys()
1480    }
1481
1482    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1483    pub fn set_excerpts_for_path(
1484        &mut self,
1485        path: PathKey,
1486        buffer: Entity<Buffer>,
1487        ranges: Vec<Range<Point>>,
1488        context_line_count: u32,
1489        cx: &mut Context<Self>,
1490    ) -> bool {
1491        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1492
1493        let mut insert_after = self
1494            .buffers_by_path
1495            .range(..path.clone())
1496            .next_back()
1497            .map(|(_, value)| *value.last().unwrap())
1498            .unwrap_or(ExcerptId::min());
1499        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1500
1501        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1502
1503        let mut new_iter = new.into_iter().peekable();
1504        let mut existing_iter = existing.into_iter().peekable();
1505
1506        let mut new_excerpt_ids = Vec::new();
1507        let mut to_remove = Vec::new();
1508        let mut to_insert = Vec::new();
1509        let mut added_a_new_excerpt = false;
1510        let snapshot = self.snapshot(cx);
1511
1512        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1513        excerpts_cursor.next(&());
1514
1515        loop {
1516            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1517                (Some(new), Some(existing)) => (new, existing),
1518                (None, None) => break,
1519                (None, Some(_)) => {
1520                    to_remove.push(existing_iter.next().unwrap());
1521                    continue;
1522                }
1523                (Some(_), None) => {
1524                    added_a_new_excerpt = true;
1525                    to_insert.push(new_iter.next().unwrap());
1526                    continue;
1527                }
1528            };
1529            let locator = snapshot.excerpt_locator_for_id(*existing);
1530            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1531            let existing_excerpt = excerpts_cursor.item().unwrap();
1532            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1533                to_remove.push(existing_iter.next().unwrap());
1534                to_insert.push(new_iter.next().unwrap());
1535                continue;
1536            }
1537
1538            let existing_start = existing_excerpt
1539                .range
1540                .context
1541                .start
1542                .to_point(&buffer_snapshot);
1543            let existing_end = existing_excerpt
1544                .range
1545                .context
1546                .end
1547                .to_point(&buffer_snapshot);
1548
1549            if existing_end < new.context.start {
1550                to_remove.push(existing_iter.next().unwrap());
1551                continue;
1552            } else if existing_start > new.context.end {
1553                to_insert.push(new_iter.next().unwrap());
1554                continue;
1555            }
1556
1557            // maybe merge overlapping excerpts?
1558            // it's hard to distinguish between a manually expanded excerpt, and one that
1559            // got smaller because of a missing diff.
1560            if existing_start == new.context.start && existing_end == new.context.end {
1561                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1562                    insert_after,
1563                    buffer.clone(),
1564                    mem::take(&mut to_insert),
1565                    cx,
1566                ));
1567                insert_after = existing_iter.next().unwrap();
1568                new_excerpt_ids.push(insert_after);
1569                new_iter.next();
1570            } else {
1571                to_remove.push(existing_iter.next().unwrap());
1572                to_insert.push(new_iter.next().unwrap());
1573            }
1574        }
1575
1576        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1577            insert_after,
1578            buffer,
1579            to_insert,
1580            cx,
1581        ));
1582        self.remove_excerpts(to_remove, cx);
1583        if new_excerpt_ids.is_empty() {
1584            self.buffers_by_path.remove(&path);
1585        } else {
1586            self.buffers_by_path.insert(path, new_excerpt_ids);
1587        }
1588
1589        added_a_new_excerpt
1590    }
1591
1592    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1593        self.buffers_by_path.keys().cloned()
1594    }
1595
1596    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1597        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1598            self.remove_excerpts(to_remove, cx)
1599        }
1600    }
1601
1602    pub fn push_multiple_excerpts_with_context_lines(
1603        &self,
1604        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1605        context_line_count: u32,
1606        cx: &mut Context<Self>,
1607    ) -> Task<Vec<Range<Anchor>>> {
1608        use futures::StreamExt;
1609
1610        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1611
1612        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1613
1614        for (buffer, ranges) in buffers_with_ranges {
1615            let (buffer_id, buffer_snapshot) =
1616                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1617
1618            buffer_ids.push(buffer_id);
1619
1620            cx.background_spawn({
1621                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1622
1623                async move {
1624                    let (excerpt_ranges, counts) =
1625                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1626                    excerpt_ranges_tx
1627                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1628                        .await
1629                        .ok();
1630                }
1631            })
1632            .detach()
1633        }
1634
1635        cx.spawn(move |this, mut cx| async move {
1636            let mut results_by_buffer_id = HashMap::default();
1637            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1638                excerpt_ranges_rx.next().await
1639            {
1640                results_by_buffer_id
1641                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1642            }
1643
1644            let mut multi_buffer_ranges = Vec::default();
1645            'outer: for buffer_id in buffer_ids {
1646                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1647                    results_by_buffer_id.remove(&buffer_id)
1648                else {
1649                    continue;
1650                };
1651
1652                let mut ranges = ranges.into_iter();
1653                let mut range_counts = range_counts.into_iter();
1654                for excerpt_ranges in excerpt_ranges.chunks(100) {
1655                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1656                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1657                    }) {
1658                        Ok(excerpt_ids) => excerpt_ids,
1659                        Err(_) => continue 'outer,
1660                    };
1661
1662                    for (excerpt_id, range_count) in
1663                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1664                    {
1665                        for range in ranges.by_ref().take(range_count) {
1666                            let start = Anchor {
1667                                buffer_id: Some(buffer_id),
1668                                excerpt_id,
1669                                text_anchor: range.start,
1670                                diff_base_anchor: None,
1671                            };
1672                            let end = Anchor {
1673                                buffer_id: Some(buffer_id),
1674                                excerpt_id,
1675                                text_anchor: range.end,
1676                                diff_base_anchor: None,
1677                            };
1678                            multi_buffer_ranges.push(start..end);
1679                        }
1680                    }
1681                }
1682            }
1683
1684            multi_buffer_ranges
1685        })
1686    }
1687
1688    pub fn insert_excerpts_after<O>(
1689        &mut self,
1690        prev_excerpt_id: ExcerptId,
1691        buffer: Entity<Buffer>,
1692        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1693        cx: &mut Context<Self>,
1694    ) -> Vec<ExcerptId>
1695    where
1696        O: text::ToOffset,
1697    {
1698        let mut ids = Vec::new();
1699        let mut next_excerpt_id =
1700            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1701                last_entry.id.0 + 1
1702            } else {
1703                1
1704            };
1705        self.insert_excerpts_with_ids_after(
1706            prev_excerpt_id,
1707            buffer,
1708            ranges.into_iter().map(|range| {
1709                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1710                ids.push(id);
1711                (id, range)
1712            }),
1713            cx,
1714        );
1715        ids
1716    }
1717
1718    pub fn insert_excerpts_with_ids_after<O>(
1719        &mut self,
1720        prev_excerpt_id: ExcerptId,
1721        buffer: Entity<Buffer>,
1722        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1723        cx: &mut Context<Self>,
1724    ) where
1725        O: text::ToOffset,
1726    {
1727        assert_eq!(self.history.transaction_depth, 0);
1728        let mut ranges = ranges.into_iter().peekable();
1729        if ranges.peek().is_none() {
1730            return Default::default();
1731        }
1732
1733        self.sync(cx);
1734
1735        let buffer_snapshot = buffer.read(cx).snapshot();
1736        let buffer_id = buffer_snapshot.remote_id();
1737
1738        let mut buffers = self.buffers.borrow_mut();
1739        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1740            self.buffer_changed_since_sync.replace(true);
1741            buffer.update(cx, |buffer, _| {
1742                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1743            });
1744            BufferState {
1745                last_version: buffer_snapshot.version().clone(),
1746                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1747                excerpts: Default::default(),
1748                _subscriptions: [
1749                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1750                    cx.subscribe(&buffer, Self::on_buffer_event),
1751                ],
1752                buffer: buffer.clone(),
1753            }
1754        });
1755
1756        let mut snapshot = self.snapshot.borrow_mut();
1757
1758        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1759        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1760        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1761        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1762        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1763
1764        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1765        new_excerpts.update_last(
1766            |excerpt| {
1767                excerpt.has_trailing_newline = true;
1768            },
1769            &(),
1770        );
1771
1772        let next_locator = if let Some(excerpt) = cursor.item() {
1773            excerpt.locator.clone()
1774        } else {
1775            Locator::max()
1776        };
1777
1778        let mut excerpts = Vec::new();
1779        while let Some((id, range)) = ranges.next() {
1780            let locator = Locator::between(&prev_locator, &next_locator);
1781            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1782                buffer_state.excerpts.insert(ix, locator.clone());
1783            }
1784            let range = ExcerptRange {
1785                context: buffer_snapshot.anchor_before(&range.context.start)
1786                    ..buffer_snapshot.anchor_after(&range.context.end),
1787                primary: range.primary.map(|primary| {
1788                    buffer_snapshot.anchor_before(&primary.start)
1789                        ..buffer_snapshot.anchor_after(&primary.end)
1790                }),
1791            };
1792            excerpts.push((id, range.clone()));
1793            let excerpt = Excerpt::new(
1794                id,
1795                locator.clone(),
1796                buffer_id,
1797                buffer_snapshot.clone(),
1798                range,
1799                ranges.peek().is_some() || cursor.item().is_some(),
1800            );
1801            new_excerpts.push(excerpt, &());
1802            prev_locator = locator.clone();
1803
1804            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1805                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1806            }
1807            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1808        }
1809
1810        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1811
1812        let suffix = cursor.suffix(&());
1813        let changed_trailing_excerpt = suffix.is_empty();
1814        new_excerpts.append(suffix, &());
1815        drop(cursor);
1816        snapshot.excerpts = new_excerpts;
1817        snapshot.excerpt_ids = new_excerpt_ids;
1818        if changed_trailing_excerpt {
1819            snapshot.trailing_excerpt_update_count += 1;
1820        }
1821
1822        self.sync_diff_transforms(
1823            &mut snapshot,
1824            vec![Edit {
1825                old: edit_start..edit_start,
1826                new: edit_start..edit_end,
1827            }],
1828            DiffChangeKind::BufferEdited,
1829        );
1830        cx.emit(Event::Edited {
1831            singleton_buffer_edited: false,
1832            edited_buffer: None,
1833        });
1834        cx.emit(Event::ExcerptsAdded {
1835            buffer,
1836            predecessor: prev_excerpt_id,
1837            excerpts,
1838        });
1839        cx.notify();
1840    }
1841
1842    pub fn clear(&mut self, cx: &mut Context<Self>) {
1843        self.sync(cx);
1844        let ids = self.excerpt_ids();
1845        self.buffers.borrow_mut().clear();
1846        let mut snapshot = self.snapshot.borrow_mut();
1847        let start = ExcerptOffset::new(0);
1848        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1849        snapshot.excerpts = Default::default();
1850        snapshot.trailing_excerpt_update_count += 1;
1851        snapshot.is_dirty = false;
1852        snapshot.has_deleted_file = false;
1853        snapshot.has_conflict = false;
1854
1855        self.sync_diff_transforms(
1856            &mut snapshot,
1857            vec![Edit {
1858                old: start..prev_len,
1859                new: start..start,
1860            }],
1861            DiffChangeKind::BufferEdited,
1862        );
1863        cx.emit(Event::Edited {
1864            singleton_buffer_edited: false,
1865            edited_buffer: None,
1866        });
1867        cx.emit(Event::ExcerptsRemoved { ids });
1868        cx.notify();
1869    }
1870
1871    pub fn excerpts_for_buffer(
1872        &self,
1873        buffer_id: BufferId,
1874        cx: &App,
1875    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1876        let mut excerpts = Vec::new();
1877        let snapshot = self.read(cx);
1878        let buffers = self.buffers.borrow();
1879        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1880        for locator in buffers
1881            .get(&buffer_id)
1882            .map(|state| &state.excerpts)
1883            .into_iter()
1884            .flatten()
1885        {
1886            cursor.seek_forward(&Some(locator), Bias::Left, &());
1887            if let Some(excerpt) = cursor.item() {
1888                if excerpt.locator == *locator {
1889                    excerpts.push((excerpt.id, excerpt.range.clone()));
1890                }
1891            }
1892        }
1893
1894        excerpts
1895    }
1896
1897    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1898        let snapshot = self.read(cx);
1899        let buffers = self.buffers.borrow();
1900        let mut excerpts = snapshot
1901            .excerpts
1902            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1903        let mut diff_transforms = snapshot
1904            .diff_transforms
1905            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1906        diff_transforms.next(&());
1907        let locators = buffers
1908            .get(&buffer_id)
1909            .into_iter()
1910            .flat_map(|state| &state.excerpts);
1911        let mut result = Vec::new();
1912        for locator in locators {
1913            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1914            if let Some(excerpt) = excerpts.item() {
1915                if excerpt.locator == *locator {
1916                    let excerpt_start = excerpts.start().1.clone();
1917                    let excerpt_end =
1918                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1919
1920                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1921                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1922                    let start = diff_transforms.start().1 .0 + overshoot;
1923
1924                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1925                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1926                    let end = diff_transforms.start().1 .0 + overshoot;
1927
1928                    result.push(start..end)
1929                }
1930            }
1931        }
1932        result
1933    }
1934
1935    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1936        self.snapshot
1937            .borrow()
1938            .excerpts
1939            .iter()
1940            .map(|entry| entry.buffer_id)
1941            .collect()
1942    }
1943
1944    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1945        self.snapshot
1946            .borrow()
1947            .excerpts
1948            .iter()
1949            .map(|entry| entry.id)
1950            .collect()
1951    }
1952
1953    pub fn excerpt_containing(
1954        &self,
1955        position: impl ToOffset,
1956        cx: &App,
1957    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1958        let snapshot = self.read(cx);
1959        let offset = position.to_offset(&snapshot);
1960
1961        let mut cursor = snapshot.cursor::<usize>();
1962        cursor.seek(&offset);
1963        cursor
1964            .excerpt()
1965            .or_else(|| snapshot.excerpts.last())
1966            .map(|excerpt| {
1967                (
1968                    excerpt.id,
1969                    self.buffers
1970                        .borrow()
1971                        .get(&excerpt.buffer_id)
1972                        .unwrap()
1973                        .buffer
1974                        .clone(),
1975                    excerpt.range.context.clone(),
1976                )
1977            })
1978    }
1979
1980    // If point is at the end of the buffer, the last excerpt is returned
1981    pub fn point_to_buffer_offset<T: ToOffset>(
1982        &self,
1983        point: T,
1984        cx: &App,
1985    ) -> Option<(Entity<Buffer>, usize)> {
1986        let snapshot = self.read(cx);
1987        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1988        Some((
1989            self.buffers
1990                .borrow()
1991                .get(&buffer.remote_id())?
1992                .buffer
1993                .clone(),
1994            offset,
1995        ))
1996    }
1997
1998    // If point is at the end of the buffer, the last excerpt is returned
1999    pub fn point_to_buffer_point<T: ToPoint>(
2000        &self,
2001        point: T,
2002        cx: &App,
2003    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2004        let snapshot = self.read(cx);
2005        let (buffer, point, is_main_buffer) =
2006            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2007        Some((
2008            self.buffers
2009                .borrow()
2010                .get(&buffer.remote_id())?
2011                .buffer
2012                .clone(),
2013            point,
2014            is_main_buffer,
2015        ))
2016    }
2017
2018    pub fn buffer_point_to_anchor(
2019        &self,
2020        buffer: &Entity<Buffer>,
2021        point: Point,
2022        cx: &App,
2023    ) -> Option<Anchor> {
2024        let mut found = None;
2025        let snapshot = buffer.read(cx).snapshot();
2026        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2027            let start = range.context.start.to_point(&snapshot);
2028            let end = range.context.end.to_point(&snapshot);
2029            if start <= point && point < end {
2030                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2031                break;
2032            }
2033            if point < start {
2034                found = Some((start, excerpt_id));
2035            }
2036            if point > end {
2037                found = Some((end, excerpt_id));
2038            }
2039        }
2040
2041        found.map(|(point, excerpt_id)| {
2042            let text_anchor = snapshot.anchor_after(point);
2043            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2044        })
2045    }
2046
2047    pub fn remove_excerpts(
2048        &mut self,
2049        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2050        cx: &mut Context<Self>,
2051    ) {
2052        self.sync(cx);
2053        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2054        if ids.is_empty() {
2055            return;
2056        }
2057
2058        let mut buffers = self.buffers.borrow_mut();
2059        let mut snapshot = self.snapshot.borrow_mut();
2060        let mut new_excerpts = SumTree::default();
2061        let mut cursor = snapshot
2062            .excerpts
2063            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2064        let mut edits = Vec::new();
2065        let mut excerpt_ids = ids.iter().copied().peekable();
2066        let mut removed_buffer_ids = Vec::new();
2067
2068        while let Some(excerpt_id) = excerpt_ids.next() {
2069            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2070            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2071            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2072
2073            if let Some(mut excerpt) = cursor.item() {
2074                if excerpt.id != excerpt_id {
2075                    continue;
2076                }
2077                let mut old_start = cursor.start().1;
2078
2079                // Skip over the removed excerpt.
2080                'remove_excerpts: loop {
2081                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2082                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2083                        if buffer_state.excerpts.is_empty() {
2084                            log::debug!(
2085                                "removing buffer and diff for buffer {}",
2086                                excerpt.buffer_id
2087                            );
2088                            buffers.remove(&excerpt.buffer_id);
2089                            removed_buffer_ids.push(excerpt.buffer_id);
2090                        }
2091                    }
2092                    cursor.next(&());
2093
2094                    // Skip over any subsequent excerpts that are also removed.
2095                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2096                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2097                        if let Some(next_excerpt) = cursor.item() {
2098                            if next_excerpt.locator == *next_locator {
2099                                excerpt_ids.next();
2100                                excerpt = next_excerpt;
2101                                continue 'remove_excerpts;
2102                            }
2103                        }
2104                    }
2105
2106                    break;
2107                }
2108
2109                // When removing the last excerpt, remove the trailing newline from
2110                // the previous excerpt.
2111                if cursor.item().is_none() && old_start.value > 0 {
2112                    old_start.value -= 1;
2113                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2114                }
2115
2116                // Push an edit for the removal of this run of excerpts.
2117                let old_end = cursor.start().1;
2118                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2119                edits.push(Edit {
2120                    old: old_start..old_end,
2121                    new: new_start..new_start,
2122                });
2123            }
2124        }
2125        let suffix = cursor.suffix(&());
2126        let changed_trailing_excerpt = suffix.is_empty();
2127        new_excerpts.append(suffix, &());
2128        drop(cursor);
2129        snapshot.excerpts = new_excerpts;
2130        for buffer_id in removed_buffer_ids {
2131            self.diffs.remove(&buffer_id);
2132            snapshot.diffs.remove(&buffer_id);
2133        }
2134
2135        if changed_trailing_excerpt {
2136            snapshot.trailing_excerpt_update_count += 1;
2137        }
2138
2139        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2140        self.buffer_changed_since_sync.replace(true);
2141        cx.emit(Event::Edited {
2142            singleton_buffer_edited: false,
2143            edited_buffer: None,
2144        });
2145        cx.emit(Event::ExcerptsRemoved { ids });
2146        cx.notify();
2147    }
2148
2149    pub fn wait_for_anchors<'a>(
2150        &self,
2151        anchors: impl 'a + Iterator<Item = Anchor>,
2152        cx: &mut Context<Self>,
2153    ) -> impl 'static + Future<Output = Result<()>> {
2154        let borrow = self.buffers.borrow();
2155        let mut error = None;
2156        let mut futures = Vec::new();
2157        for anchor in anchors {
2158            if let Some(buffer_id) = anchor.buffer_id {
2159                if let Some(buffer) = borrow.get(&buffer_id) {
2160                    buffer.buffer.update(cx, |buffer, _| {
2161                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2162                    });
2163                } else {
2164                    error = Some(anyhow!(
2165                        "buffer {buffer_id} is not part of this multi-buffer"
2166                    ));
2167                    break;
2168                }
2169            }
2170        }
2171        async move {
2172            if let Some(error) = error {
2173                Err(error)?;
2174            }
2175            for future in futures {
2176                future.await?;
2177            }
2178            Ok(())
2179        }
2180    }
2181
2182    pub fn text_anchor_for_position<T: ToOffset>(
2183        &self,
2184        position: T,
2185        cx: &App,
2186    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2187        let snapshot = self.read(cx);
2188        let anchor = snapshot.anchor_before(position);
2189        let buffer = self
2190            .buffers
2191            .borrow()
2192            .get(&anchor.buffer_id?)?
2193            .buffer
2194            .clone();
2195        Some((buffer, anchor.text_anchor))
2196    }
2197
2198    fn on_buffer_event(
2199        &mut self,
2200        buffer: Entity<Buffer>,
2201        event: &language::BufferEvent,
2202        cx: &mut Context<Self>,
2203    ) {
2204        cx.emit(match event {
2205            language::BufferEvent::Edited => Event::Edited {
2206                singleton_buffer_edited: true,
2207                edited_buffer: Some(buffer.clone()),
2208            },
2209            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2210            language::BufferEvent::Saved => Event::Saved,
2211            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2212            language::BufferEvent::Reloaded => Event::Reloaded,
2213            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2214            language::BufferEvent::LanguageChanged => {
2215                Event::LanguageChanged(buffer.read(cx).remote_id())
2216            }
2217            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2218            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2219            language::BufferEvent::Closed => Event::Closed,
2220            language::BufferEvent::Discarded => Event::Discarded,
2221            language::BufferEvent::CapabilityChanged => {
2222                self.capability = buffer.read(cx).capability();
2223                Event::CapabilityChanged
2224            }
2225            language::BufferEvent::Operation { .. } => return,
2226        });
2227    }
2228
2229    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2230        self.sync(cx);
2231        let mut snapshot = self.snapshot.borrow_mut();
2232        let diff = diff.read(cx);
2233        let buffer_id = diff.buffer_id;
2234        let diff = diff.snapshot(cx);
2235        snapshot.diffs.insert(buffer_id, diff);
2236    }
2237
2238    fn buffer_diff_changed(
2239        &mut self,
2240        diff: Entity<BufferDiff>,
2241        range: Range<text::Anchor>,
2242        cx: &mut Context<Self>,
2243    ) {
2244        self.sync(cx);
2245        self.buffer_changed_since_sync.replace(true);
2246
2247        let diff = diff.read(cx);
2248        let buffer_id = diff.buffer_id;
2249        let buffers = self.buffers.borrow();
2250        let Some(buffer_state) = buffers.get(&buffer_id) else {
2251            return;
2252        };
2253
2254        let buffer = buffer_state.buffer.read(cx);
2255        let diff_change_range = range.to_offset(buffer);
2256
2257        let new_diff = diff.snapshot(cx);
2258        let mut snapshot = self.snapshot.borrow_mut();
2259        let base_text_changed = snapshot
2260            .diffs
2261            .get(&buffer_id)
2262            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2263
2264        snapshot.diffs.insert(buffer_id, new_diff);
2265
2266        let mut excerpt_edits = Vec::new();
2267        for locator in &buffer_state.excerpts {
2268            let mut cursor = snapshot
2269                .excerpts
2270                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2271            cursor.seek_forward(&Some(locator), Bias::Left, &());
2272            if let Some(excerpt) = cursor.item() {
2273                if excerpt.locator == *locator {
2274                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2275                    if diff_change_range.end < excerpt_buffer_range.start
2276                        || diff_change_range.start > excerpt_buffer_range.end
2277                    {
2278                        continue;
2279                    }
2280                    let excerpt_start = cursor.start().1;
2281                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2282                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2283                        diff_change_range
2284                            .start
2285                            .saturating_sub(excerpt_buffer_range.start),
2286                    );
2287                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2288                        diff_change_range
2289                            .end
2290                            .saturating_sub(excerpt_buffer_range.start),
2291                    );
2292                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2293                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2294                    excerpt_edits.push(Edit {
2295                        old: edit_start..edit_end,
2296                        new: edit_start..edit_end,
2297                    });
2298                }
2299            }
2300        }
2301
2302        self.sync_diff_transforms(
2303            &mut snapshot,
2304            excerpt_edits,
2305            DiffChangeKind::DiffUpdated {
2306                base_changed: base_text_changed,
2307            },
2308        );
2309        cx.emit(Event::Edited {
2310            singleton_buffer_edited: false,
2311            edited_buffer: None,
2312        });
2313    }
2314
2315    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2316        self.buffers
2317            .borrow()
2318            .values()
2319            .map(|state| state.buffer.clone())
2320            .collect()
2321    }
2322
2323    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2324        self.buffers
2325            .borrow()
2326            .get(&buffer_id)
2327            .map(|state| state.buffer.clone())
2328    }
2329
2330    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2331        self.point_to_buffer_offset(point, cx)
2332            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2333    }
2334
2335    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2336        let buffer_id = self
2337            .snapshot
2338            .borrow()
2339            .excerpts
2340            .first()
2341            .map(|excerpt| excerpt.buffer.remote_id());
2342        buffer_id
2343            .and_then(|buffer_id| self.buffer(buffer_id))
2344            .map(|buffer| {
2345                let buffer = buffer.read(cx);
2346                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2347            })
2348            .unwrap_or_else(move || self.language_settings_at(0, cx))
2349    }
2350
2351    pub fn language_settings_at<'a, T: ToOffset>(
2352        &'a self,
2353        point: T,
2354        cx: &'a App,
2355    ) -> Cow<'a, LanguageSettings> {
2356        let mut language = None;
2357        let mut file = None;
2358        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2359            let buffer = buffer.read(cx);
2360            language = buffer.language_at(offset);
2361            file = buffer.file();
2362        }
2363        language_settings(language.map(|l| l.name()), file, cx)
2364    }
2365
2366    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2367        self.buffers
2368            .borrow()
2369            .values()
2370            .for_each(|state| f(&state.buffer))
2371    }
2372
2373    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2374        if let Some(title) = self.title.as_ref() {
2375            return title.into();
2376        }
2377
2378        if let Some(buffer) = self.as_singleton() {
2379            if let Some(file) = buffer.read(cx).file() {
2380                return file.file_name(cx).to_string_lossy();
2381            }
2382        }
2383
2384        "untitled".into()
2385    }
2386
2387    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2388        self.title = Some(title);
2389        cx.notify();
2390    }
2391
2392    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2393    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2394        for buffer_state in self.buffers.borrow().values() {
2395            buffer_state
2396                .buffer
2397                .update(cx, |buffer, _cx| buffer.refresh_preview());
2398        }
2399    }
2400
2401    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2402    pub fn preserve_preview(&self, cx: &App) -> bool {
2403        self.buffers
2404            .borrow()
2405            .values()
2406            .all(|state| state.buffer.read(cx).preserve_preview())
2407    }
2408
2409    #[cfg(any(test, feature = "test-support"))]
2410    pub fn is_parsing(&self, cx: &App) -> bool {
2411        self.as_singleton().unwrap().read(cx).is_parsing()
2412    }
2413
2414    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2415        let buffer_id = diff.read(cx).buffer_id;
2416        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2417        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2418    }
2419
2420    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2421        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2422    }
2423
2424    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2425        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2426    }
2427
2428    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2429        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2430    }
2431
2432    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2433        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2434        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2435    }
2436
2437    pub fn all_diff_hunks_expanded(&self) -> bool {
2438        self.snapshot.borrow().all_diff_hunks_expanded
2439    }
2440
2441    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2442        self.read(cx)
2443            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2444            .nth(1)
2445            .is_some()
2446    }
2447
2448    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2449        let snapshot = self.read(cx);
2450        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2451        let offset_range = range.to_offset(&snapshot);
2452        cursor.seek(&offset_range.start, Bias::Left, &());
2453        while let Some(item) = cursor.item() {
2454            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2455                break;
2456            }
2457            if item.hunk_info().is_some() {
2458                return true;
2459            }
2460            cursor.next(&());
2461        }
2462        false
2463    }
2464
2465    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2466        let snapshot = self.read(cx);
2467        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2468        for range in ranges {
2469            let range = range.to_point(&snapshot);
2470            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2471            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2472            let start = start.saturating_sub(1);
2473            let end = snapshot.len().min(end + 1);
2474            cursor.seek(&start, Bias::Right, &());
2475            while let Some(item) = cursor.item() {
2476                if *cursor.start() >= end {
2477                    break;
2478                }
2479                if item.hunk_info().is_some() {
2480                    return true;
2481                }
2482                cursor.next(&());
2483            }
2484        }
2485        false
2486    }
2487
2488    pub fn expand_or_collapse_diff_hunks_inner(
2489        &mut self,
2490        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2491        expand: bool,
2492        cx: &mut Context<Self>,
2493    ) {
2494        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2495            return;
2496        }
2497        self.sync(cx);
2498        let mut snapshot = self.snapshot.borrow_mut();
2499        let mut excerpt_edits = Vec::new();
2500        for (range, end_excerpt_id) in ranges {
2501            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2502                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2503                    continue;
2504                }
2505                let start = Anchor::in_buffer(
2506                    diff_hunk.excerpt_id,
2507                    diff_hunk.buffer_id,
2508                    diff_hunk.buffer_range.start,
2509                );
2510                let end = Anchor::in_buffer(
2511                    diff_hunk.excerpt_id,
2512                    diff_hunk.buffer_id,
2513                    diff_hunk.buffer_range.end,
2514                );
2515                let start = snapshot.excerpt_offset_for_anchor(&start);
2516                let end = snapshot.excerpt_offset_for_anchor(&end);
2517                excerpt_edits.push(text::Edit {
2518                    old: start..end,
2519                    new: start..end,
2520                });
2521            }
2522        }
2523
2524        self.sync_diff_transforms(
2525            &mut snapshot,
2526            excerpt_edits,
2527            DiffChangeKind::ExpandOrCollapseHunks { expand },
2528        );
2529        cx.emit(Event::DiffHunksToggled);
2530        cx.emit(Event::Edited {
2531            singleton_buffer_edited: false,
2532            edited_buffer: None,
2533        });
2534    }
2535
2536    pub fn expand_or_collapse_diff_hunks(
2537        &mut self,
2538        ranges: Vec<Range<Anchor>>,
2539        expand: bool,
2540        cx: &mut Context<Self>,
2541    ) {
2542        let snapshot = self.snapshot.borrow().clone();
2543        let ranges = ranges.iter().map(move |range| {
2544            let end_excerpt_id = range.end.excerpt_id;
2545            let range = range.to_point(&snapshot);
2546            let mut peek_end = range.end;
2547            if range.end.row < snapshot.max_row().0 {
2548                peek_end = Point::new(range.end.row + 1, 0);
2549            };
2550            (range.start..peek_end, end_excerpt_id)
2551        });
2552        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2553    }
2554
2555    pub fn resize_excerpt(
2556        &mut self,
2557        id: ExcerptId,
2558        range: Range<text::Anchor>,
2559        cx: &mut Context<Self>,
2560    ) {
2561        self.sync(cx);
2562
2563        let mut snapshot = self.snapshot.borrow_mut();
2564        let locator = snapshot.excerpt_locator_for_id(id);
2565        let mut new_excerpts = SumTree::default();
2566        let mut cursor = snapshot
2567            .excerpts
2568            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2569        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2570
2571        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2572        new_excerpts.append(prefix, &());
2573
2574        let mut excerpt = cursor.item().unwrap().clone();
2575        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2576
2577        excerpt.range.context.start = range.start;
2578        excerpt.range.context.end = range.end;
2579        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2580
2581        excerpt.text_summary = excerpt
2582            .buffer
2583            .text_summary_for_range(excerpt.range.context.clone());
2584
2585        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2586        let old_start_offset = cursor.start().1;
2587        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2588        let edit = Edit {
2589            old: old_start_offset..old_start_offset + old_text_len,
2590            new: new_start_offset..new_start_offset + new_text_len,
2591        };
2592
2593        if let Some(last_edit) = edits.last_mut() {
2594            if last_edit.old.end == edit.old.start {
2595                last_edit.old.end = edit.old.end;
2596                last_edit.new.end = edit.new.end;
2597            } else {
2598                edits.push(edit);
2599            }
2600        } else {
2601            edits.push(edit);
2602        }
2603
2604        new_excerpts.push(excerpt, &());
2605
2606        cursor.next(&());
2607
2608        new_excerpts.append(cursor.suffix(&()), &());
2609
2610        drop(cursor);
2611        snapshot.excerpts = new_excerpts;
2612
2613        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2614        cx.emit(Event::Edited {
2615            singleton_buffer_edited: false,
2616            edited_buffer: None,
2617        });
2618        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2619        cx.notify();
2620    }
2621
2622    pub fn expand_excerpts(
2623        &mut self,
2624        ids: impl IntoIterator<Item = ExcerptId>,
2625        line_count: u32,
2626        direction: ExpandExcerptDirection,
2627        cx: &mut Context<Self>,
2628    ) {
2629        if line_count == 0 {
2630            return;
2631        }
2632        self.sync(cx);
2633        let mut snapshot = self.snapshot.borrow_mut();
2634
2635        let ids = ids.into_iter().collect::<Vec<_>>();
2636        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2637        let mut new_excerpts = SumTree::default();
2638        let mut cursor = snapshot
2639            .excerpts
2640            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2641        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2642
2643        for locator in &locators {
2644            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2645            new_excerpts.append(prefix, &());
2646
2647            let mut excerpt = cursor.item().unwrap().clone();
2648            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2649
2650            let up_line_count = if direction.should_expand_up() {
2651                line_count
2652            } else {
2653                0
2654            };
2655
2656            let start_row = excerpt
2657                .range
2658                .context
2659                .start
2660                .to_point(&excerpt.buffer)
2661                .row
2662                .saturating_sub(up_line_count);
2663            let start_point = Point::new(start_row, 0);
2664            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2665
2666            let down_line_count = if direction.should_expand_down() {
2667                line_count
2668            } else {
2669                0
2670            };
2671
2672            let mut end_point = excerpt.buffer.clip_point(
2673                excerpt.range.context.end.to_point(&excerpt.buffer)
2674                    + Point::new(down_line_count, 0),
2675                Bias::Left,
2676            );
2677            end_point.column = excerpt.buffer.line_len(end_point.row);
2678            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2679            excerpt.max_buffer_row = end_point.row;
2680
2681            excerpt.text_summary = excerpt
2682                .buffer
2683                .text_summary_for_range(excerpt.range.context.clone());
2684
2685            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2686            let old_start_offset = cursor.start().1;
2687            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2688            let edit = Edit {
2689                old: old_start_offset..old_start_offset + old_text_len,
2690                new: new_start_offset..new_start_offset + new_text_len,
2691            };
2692
2693            if let Some(last_edit) = edits.last_mut() {
2694                if last_edit.old.end == edit.old.start {
2695                    last_edit.old.end = edit.old.end;
2696                    last_edit.new.end = edit.new.end;
2697                } else {
2698                    edits.push(edit);
2699                }
2700            } else {
2701                edits.push(edit);
2702            }
2703
2704            new_excerpts.push(excerpt, &());
2705
2706            cursor.next(&());
2707        }
2708
2709        new_excerpts.append(cursor.suffix(&()), &());
2710
2711        drop(cursor);
2712        snapshot.excerpts = new_excerpts;
2713
2714        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2715        cx.emit(Event::Edited {
2716            singleton_buffer_edited: false,
2717            edited_buffer: None,
2718        });
2719        cx.emit(Event::ExcerptsExpanded { ids });
2720        cx.notify();
2721    }
2722
2723    fn sync(&self, cx: &App) {
2724        let changed = self.buffer_changed_since_sync.replace(false);
2725        if !changed {
2726            return;
2727        }
2728
2729        let mut snapshot = self.snapshot.borrow_mut();
2730        let mut excerpts_to_edit = Vec::new();
2731        let mut non_text_state_updated = false;
2732        let mut is_dirty = false;
2733        let mut has_deleted_file = false;
2734        let mut has_conflict = false;
2735        let mut edited = false;
2736        let mut buffers = self.buffers.borrow_mut();
2737        for buffer_state in buffers.values_mut() {
2738            let buffer = buffer_state.buffer.read(cx);
2739            let version = buffer.version();
2740            let non_text_state_update_count = buffer.non_text_state_update_count();
2741
2742            let buffer_edited = version.changed_since(&buffer_state.last_version);
2743            let buffer_non_text_state_updated =
2744                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2745            if buffer_edited || buffer_non_text_state_updated {
2746                buffer_state.last_version = version;
2747                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2748                excerpts_to_edit.extend(
2749                    buffer_state
2750                        .excerpts
2751                        .iter()
2752                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2753                );
2754            }
2755
2756            edited |= buffer_edited;
2757            non_text_state_updated |= buffer_non_text_state_updated;
2758            is_dirty |= buffer.is_dirty();
2759            has_deleted_file |= buffer
2760                .file()
2761                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2762            has_conflict |= buffer.has_conflict();
2763        }
2764        if edited {
2765            snapshot.edit_count += 1;
2766        }
2767        if non_text_state_updated {
2768            snapshot.non_text_state_update_count += 1;
2769        }
2770        snapshot.is_dirty = is_dirty;
2771        snapshot.has_deleted_file = has_deleted_file;
2772        snapshot.has_conflict = has_conflict;
2773
2774        for (id, diff) in self.diffs.iter() {
2775            if snapshot.diffs.get(&id).is_none() {
2776                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2777            }
2778        }
2779
2780        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2781
2782        let mut edits = Vec::new();
2783        let mut new_excerpts = SumTree::default();
2784        let mut cursor = snapshot
2785            .excerpts
2786            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2787
2788        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2789            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2790            let old_excerpt = cursor.item().unwrap();
2791            let buffer = buffer.read(cx);
2792            let buffer_id = buffer.remote_id();
2793
2794            let mut new_excerpt;
2795            if buffer_edited {
2796                edits.extend(
2797                    buffer
2798                        .edits_since_in_range::<usize>(
2799                            old_excerpt.buffer.version(),
2800                            old_excerpt.range.context.clone(),
2801                        )
2802                        .map(|edit| {
2803                            let excerpt_old_start = cursor.start().1;
2804                            let excerpt_new_start =
2805                                ExcerptOffset::new(new_excerpts.summary().text.len);
2806                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2807                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2808                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2809                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2810                            Edit {
2811                                old: old_start..old_end,
2812                                new: new_start..new_end,
2813                            }
2814                        }),
2815                );
2816
2817                new_excerpt = Excerpt::new(
2818                    old_excerpt.id,
2819                    locator.clone(),
2820                    buffer_id,
2821                    buffer.snapshot(),
2822                    old_excerpt.range.clone(),
2823                    old_excerpt.has_trailing_newline,
2824                );
2825            } else {
2826                new_excerpt = old_excerpt.clone();
2827                new_excerpt.buffer = buffer.snapshot();
2828            }
2829
2830            new_excerpts.push(new_excerpt, &());
2831            cursor.next(&());
2832        }
2833        new_excerpts.append(cursor.suffix(&()), &());
2834
2835        drop(cursor);
2836        snapshot.excerpts = new_excerpts;
2837
2838        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2839    }
2840
2841    fn sync_diff_transforms(
2842        &self,
2843        snapshot: &mut MultiBufferSnapshot,
2844        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2845        change_kind: DiffChangeKind,
2846    ) {
2847        if excerpt_edits.is_empty() {
2848            return;
2849        }
2850
2851        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2852        let mut old_diff_transforms = snapshot
2853            .diff_transforms
2854            .cursor::<(ExcerptOffset, usize)>(&());
2855        let mut new_diff_transforms = SumTree::default();
2856        let mut old_expanded_hunks = HashSet::default();
2857        let mut output_edits = Vec::new();
2858        let mut output_delta = 0_isize;
2859        let mut at_transform_boundary = true;
2860        let mut end_of_current_insert = None;
2861
2862        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2863        while let Some(edit) = excerpt_edits.next() {
2864            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2865            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2866                excerpts.prev(&());
2867            }
2868
2869            // Keep any transforms that are before the edit.
2870            if at_transform_boundary {
2871                at_transform_boundary = false;
2872                let transforms_before_edit =
2873                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2874                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2875                if let Some(transform) = old_diff_transforms.item() {
2876                    if old_diff_transforms.end(&()).0 == edit.old.start
2877                        && old_diff_transforms.start().0 < edit.old.start
2878                    {
2879                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2880                        old_diff_transforms.next(&());
2881                    }
2882                }
2883            }
2884
2885            // Compute the start of the edit in output coordinates.
2886            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2887            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2888            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2889
2890            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2891                &edit,
2892                &mut excerpts,
2893                &mut old_diff_transforms,
2894                &mut new_diff_transforms,
2895                &mut end_of_current_insert,
2896                &mut old_expanded_hunks,
2897                &snapshot,
2898                change_kind,
2899            );
2900
2901            // Compute the end of the edit in output coordinates.
2902            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2903            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2904            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2905            let edit_new_end =
2906                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2907            let output_edit = Edit {
2908                old: edit_old_start..edit_old_end,
2909                new: edit_new_start..edit_new_end,
2910            };
2911
2912            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2913            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2914            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2915                output_edits.push(output_edit);
2916            }
2917
2918            // If this is the last edit that intersects the current diff transform,
2919            // then recreate the content up to the end of this transform, to prepare
2920            // for reusing additional slices of the old transforms.
2921            if excerpt_edits.peek().map_or(true, |next_edit| {
2922                next_edit.old.start >= old_diff_transforms.end(&()).0
2923            }) {
2924                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2925                    && match old_diff_transforms.item() {
2926                        Some(DiffTransform::BufferContent {
2927                            inserted_hunk_info: Some(hunk),
2928                            ..
2929                        }) => excerpts.item().is_some_and(|excerpt| {
2930                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2931                        }),
2932                        _ => true,
2933                    };
2934
2935                let mut excerpt_offset = edit.new.end;
2936                if !keep_next_old_transform {
2937                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2938                    old_diff_transforms.next(&());
2939                }
2940
2941                old_expanded_hunks.clear();
2942                self.push_buffer_content_transform(
2943                    &snapshot,
2944                    &mut new_diff_transforms,
2945                    excerpt_offset,
2946                    end_of_current_insert,
2947                );
2948                at_transform_boundary = true;
2949            }
2950        }
2951
2952        // Keep any transforms that are after the last edit.
2953        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2954
2955        // Ensure there's always at least one buffer content transform.
2956        if new_diff_transforms.is_empty() {
2957            new_diff_transforms.push(
2958                DiffTransform::BufferContent {
2959                    summary: Default::default(),
2960                    inserted_hunk_info: None,
2961                },
2962                &(),
2963            );
2964        }
2965
2966        self.subscriptions.publish(output_edits);
2967        drop(old_diff_transforms);
2968        drop(excerpts);
2969        snapshot.diff_transforms = new_diff_transforms;
2970        snapshot.edit_count += 1;
2971
2972        #[cfg(any(test, feature = "test-support"))]
2973        snapshot.check_invariants();
2974    }
2975
2976    #[allow(clippy::too_many_arguments)]
2977    fn recompute_diff_transforms_for_edit(
2978        &self,
2979        edit: &Edit<TypedOffset<Excerpt>>,
2980        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2981        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2982        new_diff_transforms: &mut SumTree<DiffTransform>,
2983        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2984        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2985        snapshot: &MultiBufferSnapshot,
2986        change_kind: DiffChangeKind,
2987    ) -> bool {
2988        log::trace!(
2989            "recomputing diff transform for edit {:?} => {:?}",
2990            edit.old.start.value..edit.old.end.value,
2991            edit.new.start.value..edit.new.end.value
2992        );
2993
2994        // Record which hunks were previously expanded.
2995        while let Some(item) = old_diff_transforms.item() {
2996            if let Some(hunk_info) = item.hunk_info() {
2997                log::trace!(
2998                    "previously expanded hunk at {}",
2999                    old_diff_transforms.start().0
3000                );
3001                old_expanded_hunks.insert(hunk_info);
3002            }
3003            if old_diff_transforms.end(&()).0 > edit.old.end {
3004                break;
3005            }
3006            old_diff_transforms.next(&());
3007        }
3008
3009        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3010        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3011        if old_expanded_hunks.is_empty()
3012            && change_kind == DiffChangeKind::BufferEdited
3013            && !all_diff_hunks_expanded
3014        {
3015            return false;
3016        }
3017
3018        // Visit each excerpt that intersects the edit.
3019        let mut did_expand_hunks = false;
3020        while let Some(excerpt) = excerpts.item() {
3021            // Recompute the expanded hunks in the portion of the excerpt that
3022            // intersects the edit.
3023            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3024                let buffer = &excerpt.buffer;
3025                let excerpt_start = *excerpts.start();
3026                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3027                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3028                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3029                let edit_buffer_start =
3030                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3031                let edit_buffer_end =
3032                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3033                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3034                let edit_anchor_range =
3035                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3036
3037                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3038                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3039                        continue;
3040                    }
3041
3042                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3043                    if hunk_buffer_range.start < excerpt_buffer_start {
3044                        log::trace!("skipping hunk that starts before excerpt");
3045                        continue;
3046                    }
3047
3048                    let hunk_info = DiffTransformHunkInfo {
3049                        excerpt_id: excerpt.id,
3050                        hunk_start_anchor: hunk.buffer_range.start,
3051                        hunk_secondary_status: hunk.secondary_status,
3052                    };
3053
3054                    let hunk_excerpt_start = excerpt_start
3055                        + ExcerptOffset::new(
3056                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3057                        );
3058                    let hunk_excerpt_end = excerpt_end.min(
3059                        excerpt_start
3060                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3061                    );
3062
3063                    self.push_buffer_content_transform(
3064                        snapshot,
3065                        new_diff_transforms,
3066                        hunk_excerpt_start,
3067                        *end_of_current_insert,
3068                    );
3069
3070                    // For every existing hunk, determine if it was previously expanded
3071                    // and if it should currently be expanded.
3072                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3073                    let should_expand_hunk = match &change_kind {
3074                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3075                            was_previously_expanded || all_diff_hunks_expanded
3076                        }
3077                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3078                            let intersects = hunk_buffer_range.is_empty()
3079                                || hunk_buffer_range.end > edit_buffer_start;
3080                            if *expand {
3081                                intersects || was_previously_expanded || all_diff_hunks_expanded
3082                            } else {
3083                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3084                            }
3085                        }
3086                        _ => was_previously_expanded || all_diff_hunks_expanded,
3087                    };
3088
3089                    if should_expand_hunk {
3090                        did_expand_hunks = true;
3091                        log::trace!(
3092                            "expanding hunk {:?}, excerpt:{:?}",
3093                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3094                            excerpt.id
3095                        );
3096
3097                        if !hunk.diff_base_byte_range.is_empty()
3098                            && hunk_buffer_range.start >= edit_buffer_start
3099                            && hunk_buffer_range.start <= excerpt_buffer_end
3100                        {
3101                            let base_text = diff.base_text();
3102                            let mut text_cursor =
3103                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3104                            let mut base_text_summary =
3105                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3106
3107                            let mut has_trailing_newline = false;
3108                            if base_text_summary.last_line_chars > 0 {
3109                                base_text_summary += TextSummary::newline();
3110                                has_trailing_newline = true;
3111                            }
3112
3113                            new_diff_transforms.push(
3114                                DiffTransform::DeletedHunk {
3115                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3116                                    summary: base_text_summary,
3117                                    buffer_id: excerpt.buffer_id,
3118                                    hunk_info,
3119                                    has_trailing_newline,
3120                                },
3121                                &(),
3122                            );
3123                        }
3124
3125                        if !hunk_buffer_range.is_empty() {
3126                            *end_of_current_insert =
3127                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3128                        }
3129                    }
3130                }
3131            }
3132
3133            if excerpts.end(&()) <= edit.new.end {
3134                excerpts.next(&());
3135            } else {
3136                break;
3137            }
3138        }
3139
3140        did_expand_hunks || !old_expanded_hunks.is_empty()
3141    }
3142
3143    fn append_diff_transforms(
3144        &self,
3145        new_transforms: &mut SumTree<DiffTransform>,
3146        subtree: SumTree<DiffTransform>,
3147    ) {
3148        if let Some(DiffTransform::BufferContent {
3149            inserted_hunk_info,
3150            summary,
3151        }) = subtree.first()
3152        {
3153            if self.extend_last_buffer_content_transform(
3154                new_transforms,
3155                *inserted_hunk_info,
3156                *summary,
3157            ) {
3158                let mut cursor = subtree.cursor::<()>(&());
3159                cursor.next(&());
3160                cursor.next(&());
3161                new_transforms.append(cursor.suffix(&()), &());
3162                return;
3163            }
3164        }
3165        new_transforms.append(subtree, &());
3166    }
3167
3168    fn push_diff_transform(
3169        &self,
3170        new_transforms: &mut SumTree<DiffTransform>,
3171        transform: DiffTransform,
3172    ) {
3173        if let DiffTransform::BufferContent {
3174            inserted_hunk_info: inserted_hunk_anchor,
3175            summary,
3176        } = transform
3177        {
3178            if self.extend_last_buffer_content_transform(
3179                new_transforms,
3180                inserted_hunk_anchor,
3181                summary,
3182            ) {
3183                return;
3184            }
3185        }
3186        new_transforms.push(transform, &());
3187    }
3188
3189    fn push_buffer_content_transform(
3190        &self,
3191        old_snapshot: &MultiBufferSnapshot,
3192        new_transforms: &mut SumTree<DiffTransform>,
3193        end_offset: ExcerptOffset,
3194        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3195    ) {
3196        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3197            (end_offset.min(insertion_end_offset), Some(hunk_info))
3198        });
3199        let unchanged_region = [(end_offset, None)];
3200
3201        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3202        {
3203            let start_offset = new_transforms.summary().excerpt_len();
3204            if end_offset <= start_offset {
3205                continue;
3206            }
3207            let summary_to_add = old_snapshot
3208                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3209
3210            if !self.extend_last_buffer_content_transform(
3211                new_transforms,
3212                inserted_hunk_info,
3213                summary_to_add,
3214            ) {
3215                new_transforms.push(
3216                    DiffTransform::BufferContent {
3217                        summary: summary_to_add,
3218                        inserted_hunk_info,
3219                    },
3220                    &(),
3221                )
3222            }
3223        }
3224    }
3225
3226    fn extend_last_buffer_content_transform(
3227        &self,
3228        new_transforms: &mut SumTree<DiffTransform>,
3229        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3230        summary_to_add: TextSummary,
3231    ) -> bool {
3232        let mut did_extend = false;
3233        new_transforms.update_last(
3234            |last_transform| {
3235                if let DiffTransform::BufferContent {
3236                    summary,
3237                    inserted_hunk_info: inserted_hunk_anchor,
3238                } = last_transform
3239                {
3240                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3241                        *summary += summary_to_add;
3242                        did_extend = true;
3243                    }
3244                }
3245            },
3246            &(),
3247        );
3248        did_extend
3249    }
3250}
3251
3252#[cfg(any(test, feature = "test-support"))]
3253impl MultiBuffer {
3254    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3255        let buffer = cx.new(|cx| Buffer::local(text, cx));
3256        cx.new(|cx| Self::singleton(buffer, cx))
3257    }
3258
3259    pub fn build_multi<const COUNT: usize>(
3260        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3261        cx: &mut gpui::App,
3262    ) -> Entity<Self> {
3263        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3264        for (text, ranges) in excerpts {
3265            let buffer = cx.new(|cx| Buffer::local(text, cx));
3266            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3267                context: range,
3268                primary: None,
3269            });
3270            multi.update(cx, |multi, cx| {
3271                multi.push_excerpts(buffer, excerpt_ranges, cx)
3272            });
3273        }
3274
3275        multi
3276    }
3277
3278    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3279        cx.new(|cx| Self::singleton(buffer, cx))
3280    }
3281
3282    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3283        cx.new(|cx| {
3284            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3285            let mutation_count = rng.gen_range(1..=5);
3286            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3287            multibuffer
3288        })
3289    }
3290
3291    pub fn randomly_edit(
3292        &mut self,
3293        rng: &mut impl rand::Rng,
3294        edit_count: usize,
3295        cx: &mut Context<Self>,
3296    ) {
3297        use util::RandomCharIter;
3298
3299        let snapshot = self.read(cx);
3300        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3301        let mut last_end = None;
3302        for _ in 0..edit_count {
3303            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3304                break;
3305            }
3306
3307            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3308            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3309            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3310            last_end = Some(end);
3311
3312            let mut range = start..end;
3313            if rng.gen_bool(0.2) {
3314                mem::swap(&mut range.start, &mut range.end);
3315            }
3316
3317            let new_text_len = rng.gen_range(0..10);
3318            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3319
3320            edits.push((range, new_text.into()));
3321        }
3322        log::info!("mutating multi-buffer with {:?}", edits);
3323        drop(snapshot);
3324
3325        self.edit(edits, None, cx);
3326    }
3327
3328    pub fn randomly_edit_excerpts(
3329        &mut self,
3330        rng: &mut impl rand::Rng,
3331        mutation_count: usize,
3332        cx: &mut Context<Self>,
3333    ) {
3334        use rand::prelude::*;
3335        use std::env;
3336        use util::RandomCharIter;
3337
3338        let max_excerpts = env::var("MAX_EXCERPTS")
3339            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3340            .unwrap_or(5);
3341
3342        let mut buffers = Vec::new();
3343        for _ in 0..mutation_count {
3344            if rng.gen_bool(0.05) {
3345                log::info!("Clearing multi-buffer");
3346                self.clear(cx);
3347                continue;
3348            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3349                let ids = self.excerpt_ids();
3350                let mut excerpts = HashSet::default();
3351                for _ in 0..rng.gen_range(0..ids.len()) {
3352                    excerpts.extend(ids.choose(rng).copied());
3353                }
3354
3355                let line_count = rng.gen_range(0..5);
3356
3357                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3358
3359                self.expand_excerpts(
3360                    excerpts.iter().cloned(),
3361                    line_count,
3362                    ExpandExcerptDirection::UpAndDown,
3363                    cx,
3364                );
3365                continue;
3366            }
3367
3368            let excerpt_ids = self.excerpt_ids();
3369            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3370                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3371                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3372                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3373                    let buffer = buffers.last().unwrap().read(cx);
3374                    log::info!(
3375                        "Creating new buffer {} with text: {:?}",
3376                        buffer.remote_id(),
3377                        buffer.text()
3378                    );
3379                    buffers.last().unwrap().clone()
3380                } else {
3381                    self.buffers
3382                        .borrow()
3383                        .values()
3384                        .choose(rng)
3385                        .unwrap()
3386                        .buffer
3387                        .clone()
3388                };
3389
3390                let buffer = buffer_handle.read(cx);
3391                let buffer_text = buffer.text();
3392                let ranges = (0..rng.gen_range(0..5))
3393                    .map(|_| {
3394                        let end_ix =
3395                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3396                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3397                        ExcerptRange {
3398                            context: start_ix..end_ix,
3399                            primary: None,
3400                        }
3401                    })
3402                    .collect::<Vec<_>>();
3403                log::info!(
3404                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3405                    buffer_handle.read(cx).remote_id(),
3406                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3407                    ranges
3408                        .iter()
3409                        .map(|r| &buffer_text[r.context.clone()])
3410                        .collect::<Vec<_>>()
3411                );
3412
3413                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3414                log::info!("Inserted with ids: {:?}", excerpt_id);
3415            } else {
3416                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3417                let mut excerpts_to_remove = excerpt_ids
3418                    .choose_multiple(rng, remove_count)
3419                    .cloned()
3420                    .collect::<Vec<_>>();
3421                let snapshot = self.snapshot.borrow();
3422                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3423                drop(snapshot);
3424                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3425                self.remove_excerpts(excerpts_to_remove, cx);
3426            }
3427        }
3428    }
3429
3430    pub fn randomly_mutate(
3431        &mut self,
3432        rng: &mut impl rand::Rng,
3433        mutation_count: usize,
3434        cx: &mut Context<Self>,
3435    ) {
3436        use rand::prelude::*;
3437
3438        if rng.gen_bool(0.7) || self.singleton {
3439            let buffer = self
3440                .buffers
3441                .borrow()
3442                .values()
3443                .choose(rng)
3444                .map(|state| state.buffer.clone());
3445
3446            if let Some(buffer) = buffer {
3447                buffer.update(cx, |buffer, cx| {
3448                    if rng.gen() {
3449                        buffer.randomly_edit(rng, mutation_count, cx);
3450                    } else {
3451                        buffer.randomly_undo_redo(rng, cx);
3452                    }
3453                });
3454            } else {
3455                self.randomly_edit(rng, mutation_count, cx);
3456            }
3457        } else {
3458            self.randomly_edit_excerpts(rng, mutation_count, cx);
3459        }
3460
3461        self.check_invariants(cx);
3462    }
3463
3464    fn check_invariants(&self, cx: &App) {
3465        self.read(cx).check_invariants();
3466    }
3467}
3468
3469impl EventEmitter<Event> for MultiBuffer {}
3470
3471impl MultiBufferSnapshot {
3472    pub fn text(&self) -> String {
3473        self.chunks(0..self.len(), false)
3474            .map(|chunk| chunk.text)
3475            .collect()
3476    }
3477
3478    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3479        self.reversed_chunks_in_range(0..position.to_offset(self))
3480            .flat_map(|c| c.chars().rev())
3481    }
3482
3483    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3484        let mut cursor = self.cursor::<usize>();
3485        cursor.seek(&range.end);
3486        let current_chunks = cursor.region().as_ref().map(|region| {
3487            let start_overshoot = range.start.saturating_sub(region.range.start);
3488            let end_overshoot = range.end - region.range.start;
3489            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3490            let start = region.buffer_range.start + start_overshoot;
3491            region.buffer.reversed_chunks_in_range(start..end)
3492        });
3493        ReversedMultiBufferChunks {
3494            cursor,
3495            current_chunks,
3496            start: range.start,
3497            offset: range.end,
3498        }
3499    }
3500
3501    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3502        let offset = position.to_offset(self);
3503        self.text_for_range(offset..self.len())
3504            .flat_map(|chunk| chunk.chars())
3505    }
3506
3507    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3508        self.chunks(range, false).map(|chunk| chunk.text)
3509    }
3510
3511    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3512        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3513            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3514    }
3515
3516    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3517    where
3518        T: ToOffset,
3519    {
3520        let position = position.to_offset(self);
3521        position == self.clip_offset(position, Bias::Left)
3522            && self
3523                .bytes_in_range(position..self.len())
3524                .flatten()
3525                .copied()
3526                .take(needle.len())
3527                .eq(needle.bytes())
3528    }
3529
3530    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3531        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3532    }
3533
3534    pub fn diff_hunks_in_range<T: ToPoint>(
3535        &self,
3536        range: Range<T>,
3537    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3538        let query_range = range.start.to_point(self)..range.end.to_point(self);
3539        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3540            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3541                log::debug!("no diff found for {:?}", buffer.remote_id());
3542                return None;
3543            };
3544            let buffer_start = buffer.anchor_before(buffer_range.start);
3545            let buffer_end = buffer.anchor_after(buffer_range.end);
3546            Some(
3547                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3548                    .filter_map(|hunk| {
3549                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3550                            return None;
3551                        }
3552                        Some((hunk.range.clone(), hunk))
3553                    }),
3554            )
3555        })
3556        .filter_map(move |(range, hunk, excerpt)| {
3557            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3558            {
3559                return None;
3560            }
3561            let end_row = if range.end.column == 0 {
3562                range.end.row
3563            } else {
3564                range.end.row + 1
3565            };
3566            Some(MultiBufferDiffHunk {
3567                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3568                buffer_id: excerpt.buffer_id,
3569                excerpt_id: excerpt.id,
3570                buffer_range: hunk.buffer_range.clone(),
3571                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3572                secondary_status: hunk.secondary_status,
3573            })
3574        })
3575    }
3576
3577    pub fn excerpt_ids_for_range<T: ToOffset>(
3578        &self,
3579        range: Range<T>,
3580    ) -> impl Iterator<Item = ExcerptId> + '_ {
3581        let range = range.start.to_offset(self)..range.end.to_offset(self);
3582        let mut cursor = self.cursor::<usize>();
3583        cursor.seek(&range.start);
3584        std::iter::from_fn(move || {
3585            let region = cursor.region()?;
3586            if region.range.start >= range.end {
3587                return None;
3588            }
3589            cursor.next_excerpt();
3590            Some(region.excerpt.id)
3591        })
3592    }
3593
3594    pub fn buffer_ids_for_range<T: ToOffset>(
3595        &self,
3596        range: Range<T>,
3597    ) -> impl Iterator<Item = BufferId> + '_ {
3598        let range = range.start.to_offset(self)..range.end.to_offset(self);
3599        let mut cursor = self.cursor::<usize>();
3600        cursor.seek(&range.start);
3601        std::iter::from_fn(move || {
3602            let region = cursor.region()?;
3603            if region.range.start > range.end
3604                || region.range.start == range.end && region.range.start > range.start
3605            {
3606                return None;
3607            }
3608            cursor.next_excerpt();
3609            Some(region.excerpt.buffer_id)
3610        })
3611    }
3612
3613    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3614        &self,
3615        ranges: impl Iterator<Item = Range<T>>,
3616    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3617        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3618    }
3619
3620    pub fn range_to_buffer_ranges<T: ToOffset>(
3621        &self,
3622        range: Range<T>,
3623    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
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        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3631        while let Some(region) = cursor.region() {
3632            if region.range.start > end {
3633                break;
3634            }
3635            if region.is_main_buffer {
3636                let start_overshoot = start.saturating_sub(region.range.start);
3637                let end_overshoot = end.saturating_sub(region.range.start);
3638                let start = region
3639                    .buffer_range
3640                    .end
3641                    .min(region.buffer_range.start + start_overshoot);
3642                let end = region
3643                    .buffer_range
3644                    .end
3645                    .min(region.buffer_range.start + end_overshoot);
3646                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3647                    *excerpt_id == region.excerpt.id && prev_range.end == start
3648                }) {
3649                    prev.1.end = end;
3650                } else {
3651                    result.push((region.buffer, start..end, region.excerpt.id));
3652                }
3653            }
3654            cursor.next();
3655        }
3656        result
3657    }
3658
3659    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3660        &self,
3661        range: Range<T>,
3662    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3663        let start = range.start.to_offset(&self);
3664        let end = range.end.to_offset(&self);
3665
3666        let mut cursor = self.cursor::<usize>();
3667        cursor.seek(&start);
3668
3669        std::iter::from_fn(move || {
3670            let region = cursor.region()?;
3671            if region.range.start > end {
3672                return None;
3673            }
3674            let start_overshoot = start.saturating_sub(region.range.start);
3675            let end_overshoot = end.saturating_sub(region.range.start);
3676            let start = region
3677                .buffer_range
3678                .end
3679                .min(region.buffer_range.start + start_overshoot);
3680            let end = region
3681                .buffer_range
3682                .end
3683                .min(region.buffer_range.start + end_overshoot);
3684
3685            let region_excerpt_id = region.excerpt.id;
3686            let deleted_hunk_anchor = if region.is_main_buffer {
3687                None
3688            } else {
3689                Some(self.anchor_before(region.range.start))
3690            };
3691            let result = (
3692                region.buffer,
3693                start..end,
3694                region_excerpt_id,
3695                deleted_hunk_anchor,
3696            );
3697            cursor.next();
3698            Some(result)
3699        })
3700    }
3701
3702    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3703    /// coordinates.
3704    ///
3705    /// The given callback will be called for every excerpt intersecting the given range. It will
3706    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3707    /// The callback should return an iterator of metadata items from that buffer, each paired
3708    /// with a buffer range.
3709    ///
3710    /// The returned iterator yields each of these metadata items, paired with its range in
3711    /// multi-buffer coordinates.
3712    fn lift_buffer_metadata<'a, D, M, I>(
3713        &'a self,
3714        query_range: Range<D>,
3715        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3716    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3717    where
3718        I: Iterator<Item = (Range<D>, M)> + 'a,
3719        D: TextDimension + Ord + Sub<D, Output = D>,
3720    {
3721        let max_position = D::from_text_summary(&self.text_summary());
3722        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3723        let mut cursor = self.cursor::<D>();
3724
3725        // Find the excerpt and buffer offset where the given range ends.
3726        cursor.seek(&query_range.end);
3727        let mut range_end = None;
3728        while let Some(region) = cursor.region() {
3729            if region.is_main_buffer {
3730                let mut buffer_end = region.buffer_range.start;
3731                let overshoot = if query_range.end > region.range.start {
3732                    query_range.end - region.range.start
3733                } else {
3734                    D::default()
3735                };
3736                buffer_end.add_assign(&overshoot);
3737                range_end = Some((region.excerpt.id, buffer_end));
3738                break;
3739            }
3740            cursor.next();
3741        }
3742
3743        cursor.seek(&query_range.start);
3744
3745        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3746            if region.range.start > D::zero(&()) {
3747                cursor.prev()
3748            }
3749        }
3750
3751        iter::from_fn(move || loop {
3752            let excerpt = cursor.excerpt()?;
3753
3754            // If we have already retrieved metadata for this excerpt, continue to use it.
3755            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3756                .as_mut()
3757                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3758            {
3759                Some(metadata)
3760            }
3761            // Otherwise, compute the intersection of the input range with the excerpt's range,
3762            // and retrieve the metadata for the resulting range.
3763            else {
3764                let region = cursor.region()?;
3765                let mut buffer_start;
3766                if region.is_main_buffer {
3767                    buffer_start = region.buffer_range.start;
3768                    if query_range.start > region.range.start {
3769                        let overshoot = query_range.start - region.range.start;
3770                        buffer_start.add_assign(&overshoot);
3771                    }
3772                    buffer_start = buffer_start.min(region.buffer_range.end);
3773                } else {
3774                    buffer_start = cursor.main_buffer_position()?;
3775                };
3776                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3777                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3778                    if excerpt.id == end_excerpt_id {
3779                        buffer_end = buffer_end.min(end_buffer_offset);
3780                    }
3781                }
3782
3783                if let Some(iterator) =
3784                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3785                {
3786                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3787                } else {
3788                    None
3789                }
3790            };
3791
3792            // Visit each metadata item.
3793            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3794            {
3795                // Find the multibuffer regions that contain the start and end of
3796                // the metadata item's range.
3797                if metadata_buffer_range.start > D::default() {
3798                    while let Some(region) = cursor.region() {
3799                        if region.is_main_buffer
3800                            && (region.buffer_range.end >= metadata_buffer_range.start
3801                                || cursor.is_at_end_of_excerpt())
3802                        {
3803                            break;
3804                        }
3805                        cursor.next();
3806                    }
3807                }
3808                let start_region = cursor.region()?;
3809                while let Some(region) = cursor.region() {
3810                    if region.is_main_buffer
3811                        && (region.buffer_range.end > metadata_buffer_range.end
3812                            || cursor.is_at_end_of_excerpt())
3813                    {
3814                        break;
3815                    }
3816                    cursor.next();
3817                }
3818                let end_region = cursor.region();
3819
3820                // Convert the metadata item's range into multibuffer coordinates.
3821                let mut start_position = start_region.range.start;
3822                let region_buffer_start = start_region.buffer_range.start;
3823                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3824                {
3825                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3826                    start_position = start_position.min(start_region.range.end);
3827                }
3828
3829                let mut end_position = max_position;
3830                if let Some(end_region) = &end_region {
3831                    end_position = end_region.range.start;
3832                    debug_assert!(end_region.is_main_buffer);
3833                    let region_buffer_start = end_region.buffer_range.start;
3834                    if metadata_buffer_range.end > region_buffer_start {
3835                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3836                    }
3837                    end_position = end_position.min(end_region.range.end);
3838                }
3839
3840                if start_position <= query_range.end && end_position >= query_range.start {
3841                    return Some((start_position..end_position, metadata, excerpt));
3842                }
3843            }
3844            // When there are no more metadata items for this excerpt, move to the next excerpt.
3845            else {
3846                current_excerpt_metadata.take();
3847                if let Some((end_excerpt_id, _)) = range_end {
3848                    if excerpt.id == end_excerpt_id {
3849                        return None;
3850                    }
3851                }
3852                cursor.next_excerpt();
3853            }
3854        })
3855    }
3856
3857    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3858        let offset = position.to_offset(self);
3859
3860        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3861        cursor.seek(&DimensionPair {
3862            key: offset,
3863            value: None,
3864        });
3865        cursor.seek_to_start_of_current_excerpt();
3866        let excerpt = cursor.excerpt()?;
3867
3868        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3869        let current_position = self
3870            .anchor_before(offset)
3871            .text_anchor
3872            .to_offset(&excerpt.buffer);
3873        let excerpt_end = excerpt
3874            .buffer
3875            .anchor_before(excerpt_end.min(current_position));
3876
3877        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3878            for hunk in diff.hunks_intersecting_range_rev(
3879                excerpt.range.context.start..excerpt_end,
3880                &excerpt.buffer,
3881            ) {
3882                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3883                if hunk_end >= current_position {
3884                    continue;
3885                }
3886                let start =
3887                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3888                        .to_point(&self);
3889                return Some(MultiBufferRow(start.row));
3890            }
3891        }
3892
3893        loop {
3894            cursor.prev_excerpt();
3895            let excerpt = cursor.excerpt()?;
3896
3897            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3898                continue;
3899            };
3900            let mut hunks =
3901                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3902            let Some(hunk) = hunks.next() else {
3903                continue;
3904            };
3905            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3906                .to_point(&self);
3907            return Some(MultiBufferRow(start.row));
3908        }
3909    }
3910
3911    pub fn has_diff_hunks(&self) -> bool {
3912        self.diffs.values().any(|diff| !diff.is_empty())
3913    }
3914
3915    pub fn surrounding_word<T: ToOffset>(
3916        &self,
3917        start: T,
3918        for_completion: bool,
3919    ) -> (Range<usize>, Option<CharKind>) {
3920        let mut start = start.to_offset(self);
3921        let mut end = start;
3922        let mut next_chars = self.chars_at(start).peekable();
3923        let mut prev_chars = self.reversed_chars_at(start).peekable();
3924
3925        let classifier = self
3926            .char_classifier_at(start)
3927            .for_completion(for_completion);
3928
3929        let word_kind = cmp::max(
3930            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3931            next_chars.peek().copied().map(|c| classifier.kind(c)),
3932        );
3933
3934        for ch in prev_chars {
3935            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3936                start -= ch.len_utf8();
3937            } else {
3938                break;
3939            }
3940        }
3941
3942        for ch in next_chars {
3943            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3944                end += ch.len_utf8();
3945            } else {
3946                break;
3947            }
3948        }
3949
3950        (start..end, word_kind)
3951    }
3952
3953    pub fn is_singleton(&self) -> bool {
3954        self.singleton
3955    }
3956
3957    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3958        if self.singleton {
3959            self.excerpts
3960                .iter()
3961                .next()
3962                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3963        } else {
3964            None
3965        }
3966    }
3967
3968    pub fn len(&self) -> usize {
3969        self.diff_transforms.summary().output.len
3970    }
3971
3972    pub fn is_empty(&self) -> bool {
3973        self.excerpts.summary().text.len == 0
3974    }
3975
3976    pub fn widest_line_number(&self) -> u32 {
3977        self.excerpts.summary().widest_line_number + 1
3978    }
3979
3980    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3981        let range = range.start.to_offset(self)..range.end.to_offset(self);
3982        let mut excerpts = self.cursor::<usize>();
3983        excerpts.seek(&range.start);
3984
3985        let mut chunk;
3986        let mut has_trailing_newline;
3987        let excerpt_bytes;
3988        if let Some(region) = excerpts.region() {
3989            let mut bytes = region.buffer.bytes_in_range(
3990                region.buffer_range.start + range.start - region.range.start
3991                    ..(region.buffer_range.start + range.end - region.range.start)
3992                        .min(region.buffer_range.end),
3993            );
3994            chunk = bytes.next().unwrap_or(&[][..]);
3995            excerpt_bytes = Some(bytes);
3996            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3997            if chunk.is_empty() && has_trailing_newline {
3998                chunk = b"\n";
3999                has_trailing_newline = false;
4000            }
4001        } else {
4002            chunk = &[][..];
4003            excerpt_bytes = None;
4004            has_trailing_newline = false;
4005        };
4006
4007        MultiBufferBytes {
4008            range,
4009            cursor: excerpts,
4010            excerpt_bytes,
4011            has_trailing_newline,
4012            chunk,
4013        }
4014    }
4015
4016    pub fn reversed_bytes_in_range<T: ToOffset>(
4017        &self,
4018        range: Range<T>,
4019    ) -> ReversedMultiBufferBytes {
4020        let range = range.start.to_offset(self)..range.end.to_offset(self);
4021        let mut chunks = self.reversed_chunks_in_range(range.clone());
4022        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4023        ReversedMultiBufferBytes {
4024            range,
4025            chunks,
4026            chunk,
4027        }
4028    }
4029
4030    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4031        let mut cursor = self.cursor::<Point>();
4032        cursor.seek(&Point::new(start_row.0, 0));
4033        let mut result = MultiBufferRows {
4034            point: Point::new(0, 0),
4035            is_empty: self.excerpts.is_empty(),
4036            cursor,
4037        };
4038        result.seek(start_row);
4039        result
4040    }
4041
4042    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4043        let mut chunks = MultiBufferChunks {
4044            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4045            range: 0..0,
4046            excerpts: self.excerpts.cursor(&()),
4047            diff_transforms: self.diff_transforms.cursor(&()),
4048            diffs: &self.diffs,
4049            diff_base_chunks: None,
4050            excerpt_chunks: None,
4051            buffer_chunk: None,
4052            language_aware,
4053        };
4054        let range = range.start.to_offset(self)..range.end.to_offset(self);
4055        chunks.seek(range);
4056        chunks
4057    }
4058
4059    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4060        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4061    }
4062
4063    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4064        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4065    }
4066
4067    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4068        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4069    }
4070
4071    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4072        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4073            buffer.clip_point_utf16(Unclipped(point), bias)
4074        })
4075    }
4076
4077    pub fn offset_to_point(&self, offset: usize) -> Point {
4078        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4079    }
4080
4081    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4082        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4083    }
4084
4085    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4086        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4087    }
4088
4089    pub fn point_to_offset(&self, point: Point) -> usize {
4090        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4091    }
4092
4093    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4094        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4095    }
4096
4097    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4098        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4099    }
4100
4101    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4102        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4103    }
4104
4105    fn clip_dimension<D>(
4106        &self,
4107        position: D,
4108        bias: Bias,
4109        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4110    ) -> D
4111    where
4112        D: TextDimension + Ord + Sub<D, Output = D>,
4113    {
4114        let mut cursor = self.cursor();
4115        cursor.seek(&position);
4116        if let Some(region) = cursor.region() {
4117            if position >= region.range.end {
4118                return region.range.end;
4119            }
4120            let overshoot = position - region.range.start;
4121            let mut buffer_position = region.buffer_range.start;
4122            buffer_position.add_assign(&overshoot);
4123            let clipped_buffer_position =
4124                clip_buffer_position(&region.buffer, buffer_position, bias);
4125            let mut position = region.range.start;
4126            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4127            position
4128        } else {
4129            D::from_text_summary(&self.text_summary())
4130        }
4131    }
4132
4133    fn convert_dimension<D1, D2>(
4134        &self,
4135        key: D1,
4136        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4137    ) -> D2
4138    where
4139        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4140        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4141    {
4142        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4143        cursor.seek(&DimensionPair { key, value: None });
4144        if let Some(region) = cursor.region() {
4145            if key >= region.range.end.key {
4146                return region.range.end.value.unwrap();
4147            }
4148            let start_key = region.range.start.key;
4149            let start_value = region.range.start.value.unwrap();
4150            let buffer_start_key = region.buffer_range.start.key;
4151            let buffer_start_value = region.buffer_range.start.value.unwrap();
4152            let mut buffer_key = buffer_start_key;
4153            buffer_key.add_assign(&(key - start_key));
4154            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4155            let mut result = start_value;
4156            result.add_assign(&(buffer_value - buffer_start_value));
4157            result
4158        } else {
4159            D2::from_text_summary(&self.text_summary())
4160        }
4161    }
4162
4163    pub fn point_to_buffer_offset<T: ToOffset>(
4164        &self,
4165        point: T,
4166    ) -> Option<(&BufferSnapshot, usize)> {
4167        let offset = point.to_offset(self);
4168        let mut cursor = self.cursor::<usize>();
4169        cursor.seek(&offset);
4170        let region = cursor.region()?;
4171        let overshoot = offset - region.range.start;
4172        let buffer_offset = region.buffer_range.start + overshoot;
4173        if buffer_offset == region.buffer.len() + 1
4174            && region.has_trailing_newline
4175            && !region.is_main_buffer
4176        {
4177            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4178        } else if buffer_offset > region.buffer.len() {
4179            return None;
4180        }
4181        Some((region.buffer, buffer_offset))
4182    }
4183
4184    pub fn point_to_buffer_point(
4185        &self,
4186        point: Point,
4187    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4188        let mut cursor = self.cursor::<Point>();
4189        cursor.seek(&point);
4190        let region = cursor.region()?;
4191        let overshoot = point - region.range.start;
4192        let buffer_point = region.buffer_range.start + overshoot;
4193        let excerpt = cursor.excerpt()?;
4194        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4195            && region.has_trailing_newline
4196            && !region.is_main_buffer
4197        {
4198            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4199        } else if buffer_point > region.buffer.max_point() {
4200            return None;
4201        }
4202        Some((region.buffer, buffer_point, excerpt.id))
4203    }
4204
4205    pub fn suggested_indents(
4206        &self,
4207        rows: impl IntoIterator<Item = u32>,
4208        cx: &App,
4209    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4210        let mut result = BTreeMap::new();
4211
4212        let mut rows_for_excerpt = Vec::new();
4213        let mut cursor = self.cursor::<Point>();
4214        let mut rows = rows.into_iter().peekable();
4215        let mut prev_row = u32::MAX;
4216        let mut prev_language_indent_size = IndentSize::default();
4217
4218        while let Some(row) = rows.next() {
4219            cursor.seek(&Point::new(row, 0));
4220            let Some(region) = cursor.region() else {
4221                continue;
4222            };
4223
4224            // Retrieve the language and indent size once for each disjoint region being indented.
4225            let single_indent_size = if row.saturating_sub(1) == prev_row {
4226                prev_language_indent_size
4227            } else {
4228                region
4229                    .buffer
4230                    .language_indent_size_at(Point::new(row, 0), cx)
4231            };
4232            prev_language_indent_size = single_indent_size;
4233            prev_row = row;
4234
4235            let start_buffer_row = region.buffer_range.start.row;
4236            let start_multibuffer_row = region.range.start.row;
4237            let end_multibuffer_row = region.range.end.row;
4238
4239            rows_for_excerpt.push(row);
4240            while let Some(next_row) = rows.peek().copied() {
4241                if end_multibuffer_row > next_row {
4242                    rows_for_excerpt.push(next_row);
4243                    rows.next();
4244                } else {
4245                    break;
4246                }
4247            }
4248
4249            let buffer_rows = rows_for_excerpt
4250                .drain(..)
4251                .map(|row| start_buffer_row + row - start_multibuffer_row);
4252            let buffer_indents = region
4253                .buffer
4254                .suggested_indents(buffer_rows, single_indent_size);
4255            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4256                (
4257                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4258                    indent,
4259                )
4260            });
4261            result.extend(multibuffer_indents);
4262        }
4263
4264        result
4265    }
4266
4267    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4268        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4269            let mut size = buffer.indent_size_for_line(range.start.row);
4270            size.len = size
4271                .len
4272                .min(range.end.column)
4273                .saturating_sub(range.start.column);
4274            size
4275        } else {
4276            IndentSize::spaces(0)
4277        }
4278    }
4279
4280    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4281        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4282            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4283        } else {
4284            LineIndent::spaces(0)
4285        }
4286    }
4287
4288    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4289        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4290
4291        if self.language_settings(cx).extend_comment_on_newline {
4292            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4293                let delimiters = language_scope.line_comment_prefixes();
4294                for delimiter in delimiters {
4295                    if *self
4296                        .chars_at(Point::new(row.0, indent.len() as u32))
4297                        .take(delimiter.chars().count())
4298                        .collect::<String>()
4299                        .as_str()
4300                        == **delimiter
4301                    {
4302                        indent.push_str(&delimiter);
4303                        break;
4304                    }
4305                }
4306            }
4307        }
4308
4309        indent
4310    }
4311
4312    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4313    where
4314        T: ToOffset,
4315    {
4316        for char in self.reversed_chars_at(position) {
4317            if !char.is_whitespace() {
4318                return false;
4319            }
4320            if char == '\n' {
4321                return true;
4322            }
4323        }
4324        return true;
4325    }
4326
4327    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4328        while row.0 > 0 {
4329            row.0 -= 1;
4330            if !self.is_line_blank(row) {
4331                return Some(row);
4332            }
4333        }
4334        None
4335    }
4336
4337    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4338        if let Some((_, range)) = self.buffer_line_for_row(row) {
4339            range.end.column - range.start.column
4340        } else {
4341            0
4342        }
4343    }
4344
4345    pub fn buffer_line_for_row(
4346        &self,
4347        row: MultiBufferRow,
4348    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4349        let mut cursor = self.cursor::<Point>();
4350        let point = Point::new(row.0, 0);
4351        cursor.seek(&point);
4352        let region = cursor.region()?;
4353        let overshoot = point.min(region.range.end) - region.range.start;
4354        let buffer_point = region.buffer_range.start + overshoot;
4355        if buffer_point.row > region.buffer_range.end.row {
4356            return None;
4357        }
4358        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4359        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4360            .min(region.buffer_range.end);
4361        Some((region.buffer, line_start..line_end))
4362    }
4363
4364    pub fn max_point(&self) -> Point {
4365        self.text_summary().lines
4366    }
4367
4368    pub fn max_row(&self) -> MultiBufferRow {
4369        MultiBufferRow(self.text_summary().lines.row)
4370    }
4371
4372    pub fn text_summary(&self) -> TextSummary {
4373        self.diff_transforms.summary().output
4374    }
4375
4376    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4377    where
4378        D: TextDimension,
4379        O: ToOffset,
4380    {
4381        let range = range.start.to_offset(self)..range.end.to_offset(self);
4382        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4383        cursor.seek(&range.start, Bias::Right, &());
4384
4385        let Some(first_transform) = cursor.item() else {
4386            return D::from_text_summary(&TextSummary::default());
4387        };
4388
4389        let diff_transform_start = cursor.start().0;
4390        let diff_transform_end = cursor.end(&()).0;
4391        let diff_start = range.start;
4392        let start_overshoot = diff_start - diff_transform_start;
4393        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4394
4395        let mut result = match first_transform {
4396            DiffTransform::BufferContent { .. } => {
4397                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4398                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4399                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4400            }
4401            DiffTransform::DeletedHunk {
4402                buffer_id,
4403                base_text_byte_range,
4404                has_trailing_newline,
4405                ..
4406            } => {
4407                let buffer_start = base_text_byte_range.start + start_overshoot;
4408                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4409                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4410                    panic!("{:?} is in non-existent deleted hunk", range.start)
4411                };
4412
4413                let include_trailing_newline =
4414                    *has_trailing_newline && range.end >= diff_transform_end;
4415                if include_trailing_newline {
4416                    buffer_end -= 1;
4417                }
4418
4419                let mut summary =
4420                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4421
4422                if include_trailing_newline {
4423                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4424                }
4425
4426                summary
4427            }
4428        };
4429        if range.end < diff_transform_end {
4430            return result;
4431        }
4432
4433        cursor.next(&());
4434        result.add_assign(&D::from_text_summary(&cursor.summary(
4435            &range.end,
4436            Bias::Right,
4437            &(),
4438        )));
4439
4440        let Some(last_transform) = cursor.item() else {
4441            return result;
4442        };
4443
4444        let overshoot = range.end - cursor.start().0;
4445        let suffix = match last_transform {
4446            DiffTransform::BufferContent { .. } => {
4447                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4448                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4449            }
4450            DiffTransform::DeletedHunk {
4451                base_text_byte_range,
4452                buffer_id,
4453                has_trailing_newline,
4454                ..
4455            } => {
4456                let buffer_end = base_text_byte_range.start + overshoot;
4457                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4458                    panic!("{:?} is in non-existent deleted hunk", range.end)
4459                };
4460
4461                let mut suffix = base_text
4462                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4463                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4464                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4465                }
4466                suffix
4467            }
4468        };
4469
4470        result.add_assign(&suffix);
4471        result
4472    }
4473
4474    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4475    where
4476        D: TextDimension,
4477    {
4478        // let mut range = range.start..range.end;
4479        let mut summary = D::zero(&());
4480        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4481        cursor.seek(&range.start, Bias::Right, &());
4482        if let Some(excerpt) = cursor.item() {
4483            let mut end_before_newline = cursor.end(&());
4484            if excerpt.has_trailing_newline {
4485                end_before_newline -= ExcerptOffset::new(1);
4486            }
4487
4488            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4489            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4490            let end_in_excerpt =
4491                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4492            summary.add_assign(
4493                &excerpt
4494                    .buffer
4495                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4496            );
4497
4498            if range.end > end_before_newline {
4499                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4500            }
4501
4502            cursor.next(&());
4503        }
4504
4505        if range.end > *cursor.start() {
4506            summary.add_assign(
4507                &cursor
4508                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4509                    .0,
4510            );
4511            if let Some(excerpt) = cursor.item() {
4512                range.end = cmp::max(*cursor.start(), range.end);
4513
4514                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4515                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4516                summary.add_assign(
4517                    &excerpt
4518                        .buffer
4519                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4520                );
4521            }
4522        }
4523
4524        summary
4525    }
4526
4527    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4528    where
4529        D: TextDimension + Ord + Sub<D, Output = D>,
4530    {
4531        self.summaries_for_anchors([anchor])[0]
4532    }
4533
4534    fn resolve_summary_for_anchor<D>(
4535        &self,
4536        anchor: &Anchor,
4537        excerpt_position: D,
4538        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4539    ) -> D
4540    where
4541        D: TextDimension + Ord + Sub<D, Output = D>,
4542    {
4543        loop {
4544            let transform_end_position = diff_transforms.end(&()).0 .0;
4545            let at_transform_end =
4546                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4547            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4548                diff_transforms.next(&());
4549                continue;
4550            }
4551
4552            let mut position = diff_transforms.start().1 .0;
4553            match diff_transforms.item() {
4554                Some(DiffTransform::DeletedHunk {
4555                    buffer_id,
4556                    base_text_byte_range,
4557                    ..
4558                }) => {
4559                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4560                        if let Some(base_text) =
4561                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4562                        {
4563                            if base_text.can_resolve(&diff_base_anchor) {
4564                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4565                                if base_text_offset >= base_text_byte_range.start
4566                                    && base_text_offset <= base_text_byte_range.end
4567                                {
4568                                    let position_in_hunk = base_text
4569                                        .text_summary_for_range::<D, _>(
4570                                            base_text_byte_range.start..base_text_offset,
4571                                        );
4572                                    position.add_assign(&position_in_hunk);
4573                                } else if at_transform_end {
4574                                    diff_transforms.next(&());
4575                                    continue;
4576                                }
4577                            }
4578                        }
4579                    }
4580                }
4581                _ => {
4582                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4583                        diff_transforms.next(&());
4584                        continue;
4585                    }
4586                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4587                    position.add_assign(&overshoot);
4588                }
4589            }
4590
4591            return position;
4592        }
4593    }
4594
4595    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4596        let mut cursor = self
4597            .excerpts
4598            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4599        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4600
4601        cursor.seek(&Some(locator), Bias::Left, &());
4602        if cursor.item().is_none() {
4603            cursor.next(&());
4604        }
4605
4606        let mut position = cursor.start().1;
4607        if let Some(excerpt) = cursor.item() {
4608            if excerpt.id == anchor.excerpt_id {
4609                let excerpt_buffer_start = excerpt
4610                    .buffer
4611                    .offset_for_anchor(&excerpt.range.context.start);
4612                let excerpt_buffer_end =
4613                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4614                let buffer_position = cmp::min(
4615                    excerpt_buffer_end,
4616                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4617                );
4618                if buffer_position > excerpt_buffer_start {
4619                    position.value += buffer_position - excerpt_buffer_start;
4620                }
4621            }
4622        }
4623        position
4624    }
4625
4626    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4627    where
4628        D: TextDimension + Ord + Sub<D, Output = D>,
4629        I: 'a + IntoIterator<Item = &'a Anchor>,
4630    {
4631        let mut anchors = anchors.into_iter().peekable();
4632        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4633        let mut diff_transforms_cursor = self
4634            .diff_transforms
4635            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4636        diff_transforms_cursor.next(&());
4637
4638        let mut summaries = Vec::new();
4639        while let Some(anchor) = anchors.peek() {
4640            let excerpt_id = anchor.excerpt_id;
4641            let excerpt_anchors = iter::from_fn(|| {
4642                let anchor = anchors.peek()?;
4643                if anchor.excerpt_id == excerpt_id {
4644                    Some(anchors.next().unwrap())
4645                } else {
4646                    None
4647                }
4648            });
4649
4650            let locator = self.excerpt_locator_for_id(excerpt_id);
4651            cursor.seek_forward(locator, Bias::Left, &());
4652            if cursor.item().is_none() {
4653                cursor.next(&());
4654            }
4655
4656            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4657            if let Some(excerpt) = cursor.item() {
4658                if excerpt.id != excerpt_id {
4659                    let position = self.resolve_summary_for_anchor(
4660                        &Anchor::min(),
4661                        excerpt_start_position,
4662                        &mut diff_transforms_cursor,
4663                    );
4664                    summaries.extend(excerpt_anchors.map(|_| position));
4665                    continue;
4666                }
4667                let excerpt_buffer_start =
4668                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4669                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4670                for (buffer_summary, anchor) in excerpt
4671                    .buffer
4672                    .summaries_for_anchors_with_payload::<D, _, _>(
4673                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4674                    )
4675                {
4676                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4677                    let mut position = excerpt_start_position;
4678                    if summary > excerpt_buffer_start {
4679                        position.add_assign(&(summary - excerpt_buffer_start));
4680                    }
4681
4682                    if position > diff_transforms_cursor.start().0 .0 {
4683                        diff_transforms_cursor.seek_forward(
4684                            &ExcerptDimension(position),
4685                            Bias::Left,
4686                            &(),
4687                        );
4688                    }
4689
4690                    summaries.push(self.resolve_summary_for_anchor(
4691                        anchor,
4692                        position,
4693                        &mut diff_transforms_cursor,
4694                    ));
4695                }
4696            } else {
4697                diff_transforms_cursor.seek_forward(
4698                    &ExcerptDimension(excerpt_start_position),
4699                    Bias::Left,
4700                    &(),
4701                );
4702                let position = self.resolve_summary_for_anchor(
4703                    &Anchor::max(),
4704                    excerpt_start_position,
4705                    &mut diff_transforms_cursor,
4706                );
4707                summaries.extend(excerpt_anchors.map(|_| position));
4708            }
4709        }
4710
4711        summaries
4712    }
4713
4714    pub fn dimensions_from_points<'a, D>(
4715        &'a self,
4716        points: impl 'a + IntoIterator<Item = Point>,
4717    ) -> impl 'a + Iterator<Item = D>
4718    where
4719        D: TextDimension + Sub<D, Output = D>,
4720    {
4721        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4722        cursor.seek(&DimensionPair {
4723            key: Point::default(),
4724            value: None,
4725        });
4726        let mut points = points.into_iter();
4727        iter::from_fn(move || {
4728            let point = points.next()?;
4729
4730            cursor.seek_forward(&DimensionPair {
4731                key: point,
4732                value: None,
4733            });
4734
4735            if let Some(region) = cursor.region() {
4736                let overshoot = point - region.range.start.key;
4737                let buffer_point = region.buffer_range.start.key + overshoot;
4738                let mut position = region.range.start.value.unwrap();
4739                position.add_assign(
4740                    &region
4741                        .buffer
4742                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4743                );
4744                if point == region.range.end.key && region.has_trailing_newline {
4745                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4746                }
4747                return Some(position);
4748            } else {
4749                return Some(D::from_text_summary(&self.text_summary()));
4750            }
4751        })
4752    }
4753
4754    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4755    where
4756        I: 'a + IntoIterator<Item = &'a Anchor>,
4757    {
4758        let mut anchors = anchors.into_iter().enumerate().peekable();
4759        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4760        cursor.next(&());
4761
4762        let mut result = Vec::new();
4763
4764        while let Some((_, anchor)) = anchors.peek() {
4765            let old_excerpt_id = anchor.excerpt_id;
4766
4767            // Find the location where this anchor's excerpt should be.
4768            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4769            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4770
4771            if cursor.item().is_none() {
4772                cursor.next(&());
4773            }
4774
4775            let next_excerpt = cursor.item();
4776            let prev_excerpt = cursor.prev_item();
4777
4778            // Process all of the anchors for this excerpt.
4779            while let Some((_, anchor)) = anchors.peek() {
4780                if anchor.excerpt_id != old_excerpt_id {
4781                    break;
4782                }
4783                let (anchor_ix, anchor) = anchors.next().unwrap();
4784                let mut anchor = *anchor;
4785
4786                // Leave min and max anchors unchanged if invalid or
4787                // if the old excerpt still exists at this location
4788                let mut kept_position = next_excerpt
4789                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4790                    || old_excerpt_id == ExcerptId::max()
4791                    || old_excerpt_id == ExcerptId::min();
4792
4793                // If the old excerpt no longer exists at this location, then attempt to
4794                // find an equivalent position for this anchor in an adjacent excerpt.
4795                if !kept_position {
4796                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4797                        if excerpt.contains(&anchor) {
4798                            anchor.excerpt_id = excerpt.id;
4799                            kept_position = true;
4800                            break;
4801                        }
4802                    }
4803                }
4804
4805                // If there's no adjacent excerpt that contains the anchor's position,
4806                // then report that the anchor has lost its position.
4807                if !kept_position {
4808                    anchor = if let Some(excerpt) = next_excerpt {
4809                        let mut text_anchor = excerpt
4810                            .range
4811                            .context
4812                            .start
4813                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4814                        if text_anchor
4815                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4816                            .is_gt()
4817                        {
4818                            text_anchor = excerpt.range.context.end;
4819                        }
4820                        Anchor {
4821                            buffer_id: Some(excerpt.buffer_id),
4822                            excerpt_id: excerpt.id,
4823                            text_anchor,
4824                            diff_base_anchor: None,
4825                        }
4826                    } else if let Some(excerpt) = prev_excerpt {
4827                        let mut text_anchor = excerpt
4828                            .range
4829                            .context
4830                            .end
4831                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4832                        if text_anchor
4833                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4834                            .is_lt()
4835                        {
4836                            text_anchor = excerpt.range.context.start;
4837                        }
4838                        Anchor {
4839                            buffer_id: Some(excerpt.buffer_id),
4840                            excerpt_id: excerpt.id,
4841                            text_anchor,
4842                            diff_base_anchor: None,
4843                        }
4844                    } else if anchor.text_anchor.bias == Bias::Left {
4845                        Anchor::min()
4846                    } else {
4847                        Anchor::max()
4848                    };
4849                }
4850
4851                result.push((anchor_ix, anchor, kept_position));
4852            }
4853        }
4854        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4855        result
4856    }
4857
4858    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4859        self.anchor_at(position, Bias::Left)
4860    }
4861
4862    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4863        self.anchor_at(position, Bias::Right)
4864    }
4865
4866    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4867        let offset = position.to_offset(self);
4868
4869        // Find the given position in the diff transforms. Determine the corresponding
4870        // offset in the excerpts, and whether the position is within a deleted hunk.
4871        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4872        diff_transforms.seek(&offset, Bias::Right, &());
4873
4874        if offset == diff_transforms.start().0 && bias == Bias::Left {
4875            if let Some(prev_item) = diff_transforms.prev_item() {
4876                match prev_item {
4877                    DiffTransform::DeletedHunk { .. } => {
4878                        diff_transforms.prev(&());
4879                    }
4880                    _ => {}
4881                }
4882            }
4883        }
4884        let offset_in_transform = offset - diff_transforms.start().0;
4885        let mut excerpt_offset = diff_transforms.start().1;
4886        let mut diff_base_anchor = None;
4887        if let Some(DiffTransform::DeletedHunk {
4888            buffer_id,
4889            base_text_byte_range,
4890            has_trailing_newline,
4891            ..
4892        }) = diff_transforms.item()
4893        {
4894            let diff = self.diffs.get(buffer_id).expect("missing diff");
4895            if offset_in_transform > base_text_byte_range.len() {
4896                debug_assert!(*has_trailing_newline);
4897                bias = Bias::Right;
4898            } else {
4899                diff_base_anchor = Some(
4900                    diff.base_text()
4901                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4902                );
4903                bias = Bias::Left;
4904            }
4905        } else {
4906            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4907        };
4908
4909        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4910            return Anchor {
4911                buffer_id: Some(buffer_id),
4912                excerpt_id: *excerpt_id,
4913                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4914                diff_base_anchor,
4915            };
4916        }
4917
4918        let mut excerpts = self
4919            .excerpts
4920            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4921        excerpts.seek(&excerpt_offset, Bias::Right, &());
4922        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4923            excerpts.prev(&());
4924        }
4925        if let Some(excerpt) = excerpts.item() {
4926            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4927            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4928                overshoot -= 1;
4929                bias = Bias::Right;
4930            }
4931
4932            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4933            let text_anchor =
4934                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4935            Anchor {
4936                buffer_id: Some(excerpt.buffer_id),
4937                excerpt_id: excerpt.id,
4938                text_anchor,
4939                diff_base_anchor,
4940            }
4941        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4942            Anchor::min()
4943        } else {
4944            Anchor::max()
4945        }
4946    }
4947
4948    /// Returns an anchor for the given excerpt and text anchor,
4949    /// returns None if the excerpt_id is no longer valid.
4950    pub fn anchor_in_excerpt(
4951        &self,
4952        excerpt_id: ExcerptId,
4953        text_anchor: text::Anchor,
4954    ) -> Option<Anchor> {
4955        let locator = self.excerpt_locator_for_id(excerpt_id);
4956        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4957        cursor.seek(locator, Bias::Left, &());
4958        if let Some(excerpt) = cursor.item() {
4959            if excerpt.id == excerpt_id {
4960                let text_anchor = excerpt.clip_anchor(text_anchor);
4961                drop(cursor);
4962                return Some(Anchor {
4963                    buffer_id: Some(excerpt.buffer_id),
4964                    excerpt_id,
4965                    text_anchor,
4966                    diff_base_anchor: None,
4967                });
4968            }
4969        }
4970        None
4971    }
4972
4973    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4974        Some(self.excerpt(excerpt_id)?.range.context.clone())
4975    }
4976
4977    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4978        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4979            true
4980        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4981            excerpt.buffer.can_resolve(&anchor.text_anchor)
4982        } else {
4983            false
4984        }
4985    }
4986
4987    pub fn excerpts(
4988        &self,
4989    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4990        self.excerpts
4991            .iter()
4992            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4993    }
4994
4995    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4996        let excerpts = self.excerpts.cursor(&());
4997        let diff_transforms = self.diff_transforms.cursor(&());
4998        MultiBufferCursor {
4999            excerpts,
5000            diff_transforms,
5001            diffs: &self.diffs,
5002            cached_region: None,
5003        }
5004    }
5005
5006    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5007        let start_locator = self.excerpt_locator_for_id(id);
5008        let mut excerpts = self
5009            .excerpts
5010            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5011        excerpts.seek(&Some(start_locator), Bias::Left, &());
5012        excerpts.prev(&());
5013
5014        let mut diff_transforms = self
5015            .diff_transforms
5016            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5017        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5018        if diff_transforms.end(&()).1 < excerpts.start().1 {
5019            diff_transforms.next(&());
5020        }
5021
5022        let excerpt = excerpts.item()?;
5023        Some(MultiBufferExcerpt {
5024            excerpt,
5025            offset: diff_transforms.start().0 .0,
5026            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5027            excerpt_offset: excerpts.start().1.clone(),
5028            diff_transforms,
5029        })
5030    }
5031
5032    pub fn excerpt_boundaries_in_range<R, T>(
5033        &self,
5034        range: R,
5035    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5036    where
5037        R: RangeBounds<T>,
5038        T: ToOffset,
5039    {
5040        let start_offset;
5041        let start = match range.start_bound() {
5042            Bound::Included(start) => {
5043                start_offset = start.to_offset(self);
5044                Bound::Included(start_offset)
5045            }
5046            Bound::Excluded(_) => {
5047                panic!("not supported")
5048            }
5049            Bound::Unbounded => {
5050                start_offset = 0;
5051                Bound::Unbounded
5052            }
5053        };
5054        let end = match range.end_bound() {
5055            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5056            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5057            Bound::Unbounded => Bound::Unbounded,
5058        };
5059        let bounds = (start, end);
5060
5061        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5062        cursor.seek(&DimensionPair {
5063            key: start_offset,
5064            value: None,
5065        });
5066
5067        if cursor
5068            .region()
5069            .is_some_and(|region| bounds.contains(&region.range.start.key))
5070        {
5071            cursor.prev_excerpt();
5072        } else {
5073            cursor.seek_to_start_of_current_excerpt();
5074        }
5075        let mut prev_region = cursor.region();
5076
5077        cursor.next_excerpt();
5078
5079        let mut visited_end = false;
5080        iter::from_fn(move || loop {
5081            if self.singleton {
5082                return None;
5083            }
5084
5085            let next_region = cursor.region();
5086            cursor.next_excerpt();
5087
5088            let next_region_start = if let Some(region) = &next_region {
5089                if !bounds.contains(&region.range.start.key) {
5090                    prev_region = next_region;
5091                    continue;
5092                }
5093                region.range.start.value.unwrap()
5094            } else {
5095                if !bounds.contains(&self.len()) {
5096                    return None;
5097                }
5098                self.max_point()
5099            };
5100            let next_region_end = if let Some(region) = cursor.region() {
5101                region.range.start.value.unwrap()
5102            } else {
5103                self.max_point()
5104            };
5105
5106            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5107                id: region.excerpt.id,
5108                buffer: region.excerpt.buffer.clone(),
5109                buffer_id: region.excerpt.buffer_id,
5110                range: region.excerpt.range.clone(),
5111                end_row: MultiBufferRow(next_region_start.row),
5112            });
5113
5114            let next = next_region.as_ref().map(|region| ExcerptInfo {
5115                id: region.excerpt.id,
5116                buffer: region.excerpt.buffer.clone(),
5117                buffer_id: region.excerpt.buffer_id,
5118                range: region.excerpt.range.clone(),
5119                end_row: if region.excerpt.has_trailing_newline {
5120                    MultiBufferRow(next_region_end.row - 1)
5121                } else {
5122                    MultiBufferRow(next_region_end.row)
5123                },
5124            });
5125
5126            if next.is_none() {
5127                if visited_end {
5128                    return None;
5129                } else {
5130                    visited_end = true;
5131                }
5132            }
5133
5134            let row = MultiBufferRow(next_region_start.row);
5135
5136            prev_region = next_region;
5137
5138            return Some(ExcerptBoundary { row, prev, next });
5139        })
5140    }
5141
5142    pub fn edit_count(&self) -> usize {
5143        self.edit_count
5144    }
5145
5146    pub fn non_text_state_update_count(&self) -> usize {
5147        self.non_text_state_update_count
5148    }
5149
5150    /// Returns the smallest enclosing bracket ranges containing the given range or
5151    /// None if no brackets contain range or the range is not contained in a single
5152    /// excerpt
5153    ///
5154    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5155    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5156        &self,
5157        range: Range<T>,
5158        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5159    ) -> Option<(Range<usize>, Range<usize>)> {
5160        let range = range.start.to_offset(self)..range.end.to_offset(self);
5161        let mut excerpt = self.excerpt_containing(range.clone())?;
5162        let buffer = excerpt.buffer();
5163        let excerpt_buffer_range = excerpt.buffer_range();
5164
5165        // Filter to ranges contained in the excerpt
5166        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5167            excerpt_buffer_range.contains(&open.start)
5168                && excerpt_buffer_range.contains(&close.end)
5169                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5170        };
5171
5172        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5173            excerpt.map_range_to_buffer(range),
5174            Some(&range_filter),
5175        )?;
5176
5177        Some((
5178            excerpt.map_range_from_buffer(open),
5179            excerpt.map_range_from_buffer(close),
5180        ))
5181    }
5182
5183    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5184    /// not contained in a single excerpt
5185    pub fn enclosing_bracket_ranges<T: ToOffset>(
5186        &self,
5187        range: Range<T>,
5188    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5189        let range = range.start.to_offset(self)..range.end.to_offset(self);
5190        let mut excerpt = self.excerpt_containing(range.clone())?;
5191
5192        Some(
5193            excerpt
5194                .buffer()
5195                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5196                .filter_map(move |pair| {
5197                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5198                        Some((
5199                            excerpt.map_range_from_buffer(pair.open_range),
5200                            excerpt.map_range_from_buffer(pair.close_range),
5201                        ))
5202                    } else {
5203                        None
5204                    }
5205                }),
5206        )
5207    }
5208
5209    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5210    /// not contained in a single excerpt
5211    pub fn text_object_ranges<T: ToOffset>(
5212        &self,
5213        range: Range<T>,
5214        options: TreeSitterOptions,
5215    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5216        let range = range.start.to_offset(self)..range.end.to_offset(self);
5217        self.excerpt_containing(range.clone())
5218            .map(|mut excerpt| {
5219                excerpt
5220                    .buffer()
5221                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5222                    .filter_map(move |(range, text_object)| {
5223                        if excerpt.contains_buffer_range(range.clone()) {
5224                            Some((excerpt.map_range_from_buffer(range), text_object))
5225                        } else {
5226                            None
5227                        }
5228                    })
5229            })
5230            .into_iter()
5231            .flatten()
5232    }
5233
5234    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5235    /// not contained in a single excerpt
5236    pub fn bracket_ranges<T: ToOffset>(
5237        &self,
5238        range: Range<T>,
5239    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5240        let range = range.start.to_offset(self)..range.end.to_offset(self);
5241        let mut excerpt = self.excerpt_containing(range.clone())?;
5242
5243        Some(
5244            excerpt
5245                .buffer()
5246                .bracket_ranges(excerpt.map_range_to_buffer(range))
5247                .filter_map(move |pair| {
5248                    let buffer_range = pair.open_range.start..pair.close_range.end;
5249                    if excerpt.contains_buffer_range(buffer_range) {
5250                        Some((
5251                            excerpt.map_range_from_buffer(pair.open_range),
5252                            excerpt.map_range_from_buffer(pair.close_range),
5253                        ))
5254                    } else {
5255                        None
5256                    }
5257                }),
5258        )
5259    }
5260
5261    pub fn redacted_ranges<'a, T: ToOffset>(
5262        &'a self,
5263        range: Range<T>,
5264        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5265    ) -> impl Iterator<Item = Range<usize>> + 'a {
5266        let range = range.start.to_offset(self)..range.end.to_offset(self);
5267        self.lift_buffer_metadata(range, move |buffer, range| {
5268            if redaction_enabled(buffer.file()) {
5269                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5270            } else {
5271                None
5272            }
5273        })
5274        .map(|(range, _, _)| range)
5275    }
5276
5277    pub fn runnable_ranges(
5278        &self,
5279        range: Range<Anchor>,
5280    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5281        let range = range.start.to_offset(self)..range.end.to_offset(self);
5282        self.lift_buffer_metadata(range, move |buffer, range| {
5283            Some(
5284                buffer
5285                    .runnable_ranges(range.clone())
5286                    .filter(move |runnable| {
5287                        runnable.run_range.start >= range.start
5288                            && runnable.run_range.end < range.end
5289                    })
5290                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5291            )
5292        })
5293        .map(|(run_range, runnable, _)| language::RunnableRange {
5294            run_range,
5295            ..runnable
5296        })
5297    }
5298
5299    pub fn line_indents(
5300        &self,
5301        start_row: MultiBufferRow,
5302        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5303    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5304        let max_point = self.max_point();
5305        let mut cursor = self.cursor::<Point>();
5306        cursor.seek(&Point::new(start_row.0, 0));
5307        iter::from_fn(move || {
5308            let mut region = cursor.region()?;
5309            while !buffer_filter(&region.excerpt.buffer) {
5310                cursor.next();
5311                region = cursor.region()?;
5312            }
5313            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5314            let buffer_start_row =
5315                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5316
5317            let buffer_end_row = if region.is_main_buffer
5318                && (region.has_trailing_newline || region.range.end == max_point)
5319            {
5320                region.buffer_range.end.row
5321            } else {
5322                region.buffer_range.end.row.saturating_sub(1)
5323            };
5324
5325            let line_indents = region
5326                .buffer
5327                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5328            cursor.next();
5329            return Some(line_indents.map(move |(buffer_row, indent)| {
5330                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5331                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5332            }));
5333        })
5334        .flatten()
5335    }
5336
5337    pub fn reversed_line_indents(
5338        &self,
5339        end_row: MultiBufferRow,
5340        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5341    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5342        let max_point = self.max_point();
5343        let mut cursor = self.cursor::<Point>();
5344        cursor.seek(&Point::new(end_row.0, 0));
5345        iter::from_fn(move || {
5346            let mut region = cursor.region()?;
5347            while !buffer_filter(&region.excerpt.buffer) {
5348                cursor.prev();
5349                region = cursor.region()?;
5350            }
5351
5352            let buffer_start_row = region.buffer_range.start.row;
5353            let buffer_end_row = if region.is_main_buffer
5354                && (region.has_trailing_newline || region.range.end == max_point)
5355            {
5356                region.buffer_range.end.row + 1
5357            } else {
5358                region.buffer_range.end.row
5359            };
5360
5361            let overshoot = end_row.0 - region.range.start.row;
5362            let buffer_end_row =
5363                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5364
5365            let line_indents = region
5366                .buffer
5367                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5368            cursor.prev();
5369            return Some(line_indents.map(move |(buffer_row, indent)| {
5370                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5371                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5372            }));
5373        })
5374        .flatten()
5375    }
5376
5377    pub async fn enclosing_indent(
5378        &self,
5379        mut target_row: MultiBufferRow,
5380    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5381        let max_row = MultiBufferRow(self.max_point().row);
5382        if target_row >= max_row {
5383            return None;
5384        }
5385
5386        let mut target_indent = self.line_indent_for_row(target_row);
5387
5388        // If the current row is at the start of an indented block, we want to return this
5389        // block as the enclosing indent.
5390        if !target_indent.is_line_empty() && target_row < max_row {
5391            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5392            if !next_line_indent.is_line_empty()
5393                && target_indent.raw_len() < next_line_indent.raw_len()
5394            {
5395                target_indent = next_line_indent;
5396                target_row.0 += 1;
5397            }
5398        }
5399
5400        const SEARCH_ROW_LIMIT: u32 = 25000;
5401        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5402        const YIELD_INTERVAL: u32 = 100;
5403
5404        let mut accessed_row_counter = 0;
5405
5406        // If there is a blank line at the current row, search for the next non indented lines
5407        if target_indent.is_line_empty() {
5408            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5409            let end =
5410                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5411
5412            let mut non_empty_line_above = None;
5413            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5414                if row < start {
5415                    break;
5416                }
5417                accessed_row_counter += 1;
5418                if accessed_row_counter == YIELD_INTERVAL {
5419                    accessed_row_counter = 0;
5420                    yield_now().await;
5421                }
5422                if !indent.is_line_empty() {
5423                    non_empty_line_above = Some((row, indent));
5424                    break;
5425                }
5426            }
5427
5428            let mut non_empty_line_below = None;
5429            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5430                if row > end {
5431                    break;
5432                }
5433                accessed_row_counter += 1;
5434                if accessed_row_counter == YIELD_INTERVAL {
5435                    accessed_row_counter = 0;
5436                    yield_now().await;
5437                }
5438                if !indent.is_line_empty() {
5439                    non_empty_line_below = Some((row, indent));
5440                    break;
5441                }
5442            }
5443
5444            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5445                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5446                    if above_indent.raw_len() >= below_indent.raw_len() {
5447                        (above_row, above_indent)
5448                    } else {
5449                        (below_row, below_indent)
5450                    }
5451                }
5452                (Some(above), None) => above,
5453                (None, Some(below)) => below,
5454                _ => return None,
5455            };
5456
5457            target_indent = indent;
5458            target_row = row;
5459        }
5460
5461        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5462        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5463
5464        let mut start_indent = None;
5465        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5466            if row < start {
5467                break;
5468            }
5469            accessed_row_counter += 1;
5470            if accessed_row_counter == YIELD_INTERVAL {
5471                accessed_row_counter = 0;
5472                yield_now().await;
5473            }
5474            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5475                start_indent = Some((row, indent));
5476                break;
5477            }
5478        }
5479        let (start_row, start_indent_size) = start_indent?;
5480
5481        let mut end_indent = (end, None);
5482        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5483            if row > end {
5484                break;
5485            }
5486            accessed_row_counter += 1;
5487            if accessed_row_counter == YIELD_INTERVAL {
5488                accessed_row_counter = 0;
5489                yield_now().await;
5490            }
5491            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5492                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5493                break;
5494            }
5495        }
5496        let (end_row, end_indent_size) = end_indent;
5497
5498        let indent = if let Some(end_indent_size) = end_indent_size {
5499            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5500                start_indent_size
5501            } else {
5502                end_indent_size
5503            }
5504        } else {
5505            start_indent_size
5506        };
5507
5508        Some((start_row..end_row, indent))
5509    }
5510
5511    pub fn indent_guides_in_range<T: ToPoint>(
5512        &self,
5513        range: Range<T>,
5514        ignore_disabled_for_language: bool,
5515        cx: &App,
5516    ) -> impl Iterator<Item = IndentGuide> {
5517        let range = range.start.to_point(self)..range.end.to_point(self);
5518        let start_row = MultiBufferRow(range.start.row);
5519        let end_row = MultiBufferRow(range.end.row);
5520
5521        let mut row_indents = self.line_indents(start_row, |buffer| {
5522            let settings =
5523                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5524            settings.indent_guides.enabled || ignore_disabled_for_language
5525        });
5526
5527        let mut result = Vec::new();
5528        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5529
5530        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5531            if first_row > end_row {
5532                break;
5533            }
5534            let current_depth = indent_stack.len() as u32;
5535
5536            let settings =
5537                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5538            let tab_size = settings.tab_size.get() as u32;
5539
5540            // When encountering empty, continue until found useful line indent
5541            // then add to the indent stack with the depth found
5542            let mut found_indent = false;
5543            let mut last_row = first_row;
5544            if line_indent.is_line_empty() {
5545                while !found_indent {
5546                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5547                        break;
5548                    };
5549                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5550                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5551                        break;
5552                    }
5553
5554                    if new_line_indent.is_line_empty() {
5555                        continue;
5556                    }
5557                    last_row = target_row.min(end_row);
5558                    line_indent = new_line_indent;
5559                    found_indent = true;
5560                    break;
5561                }
5562            } else {
5563                found_indent = true
5564            }
5565
5566            let depth = if found_indent {
5567                line_indent.len(tab_size) / tab_size
5568                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5569            } else {
5570                current_depth
5571            };
5572
5573            match depth.cmp(&current_depth) {
5574                cmp::Ordering::Less => {
5575                    for _ in 0..(current_depth - depth) {
5576                        let mut indent = indent_stack.pop().unwrap();
5577                        if last_row != first_row {
5578                            // In this case, we landed on an empty row, had to seek forward,
5579                            // and discovered that the indent we where on is ending.
5580                            // This means that the last display row must
5581                            // be on line that ends this indent range, so we
5582                            // should display the range up to the first non-empty line
5583                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5584                        }
5585
5586                        result.push(indent)
5587                    }
5588                }
5589                cmp::Ordering::Greater => {
5590                    for next_depth in current_depth..depth {
5591                        indent_stack.push(IndentGuide {
5592                            buffer_id: buffer.remote_id(),
5593                            start_row: first_row,
5594                            end_row: last_row,
5595                            depth: next_depth,
5596                            tab_size,
5597                            settings: settings.indent_guides,
5598                        });
5599                    }
5600                }
5601                _ => {}
5602            }
5603
5604            for indent in indent_stack.iter_mut() {
5605                indent.end_row = last_row;
5606            }
5607        }
5608
5609        result.extend(indent_stack);
5610        result.into_iter()
5611    }
5612
5613    pub fn trailing_excerpt_update_count(&self) -> usize {
5614        self.trailing_excerpt_update_count
5615    }
5616
5617    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5618        self.point_to_buffer_offset(point)
5619            .and_then(|(buffer, _)| buffer.file())
5620    }
5621
5622    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5623        self.point_to_buffer_offset(point)
5624            .and_then(|(buffer, offset)| buffer.language_at(offset))
5625    }
5626
5627    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5628        self.excerpts
5629            .first()
5630            .map(|excerpt| &excerpt.buffer)
5631            .map(|buffer| {
5632                language_settings(
5633                    buffer.language().map(|language| language.name()),
5634                    buffer.file(),
5635                    cx,
5636                )
5637            })
5638            .unwrap_or_else(move || self.language_settings_at(0, cx))
5639    }
5640
5641    pub fn language_settings_at<'a, T: ToOffset>(
5642        &'a self,
5643        point: T,
5644        cx: &'a App,
5645    ) -> Cow<'a, LanguageSettings> {
5646        let mut language = None;
5647        let mut file = None;
5648        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5649            language = buffer.language_at(offset);
5650            file = buffer.file();
5651        }
5652        language_settings(language.map(|l| l.name()), file, cx)
5653    }
5654
5655    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5656        self.point_to_buffer_offset(point)
5657            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5658    }
5659
5660    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5661        self.point_to_buffer_offset(point)
5662            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5663            .unwrap_or_default()
5664    }
5665
5666    pub fn language_indent_size_at<T: ToOffset>(
5667        &self,
5668        position: T,
5669        cx: &App,
5670    ) -> Option<IndentSize> {
5671        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5672        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5673    }
5674
5675    pub fn is_dirty(&self) -> bool {
5676        self.is_dirty
5677    }
5678
5679    pub fn has_deleted_file(&self) -> bool {
5680        self.has_deleted_file
5681    }
5682
5683    pub fn has_conflict(&self) -> bool {
5684        self.has_conflict
5685    }
5686
5687    pub fn has_diagnostics(&self) -> bool {
5688        self.excerpts
5689            .iter()
5690            .any(|excerpt| excerpt.buffer.has_diagnostics())
5691    }
5692
5693    pub fn diagnostic_group(
5694        &self,
5695        buffer_id: BufferId,
5696        group_id: usize,
5697    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5698        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5699            if buffer.remote_id() != buffer_id {
5700                return None;
5701            };
5702            Some(
5703                buffer
5704                    .diagnostic_group(group_id)
5705                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5706            )
5707        })
5708        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5709    }
5710
5711    pub fn diagnostics_in_range<'a, T>(
5712        &'a self,
5713        range: Range<T>,
5714    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5715    where
5716        T: 'a
5717            + text::ToOffset
5718            + text::FromAnchor
5719            + TextDimension
5720            + Ord
5721            + Sub<T, Output = T>
5722            + fmt::Debug,
5723    {
5724        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5725            Some(
5726                buffer
5727                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5728                    .map(|entry| (entry.range, entry.diagnostic)),
5729            )
5730        })
5731        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5732    }
5733
5734    pub fn syntax_ancestor<T: ToOffset>(
5735        &self,
5736        range: Range<T>,
5737    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5738        let range = range.start.to_offset(self)..range.end.to_offset(self);
5739        let mut excerpt = self.excerpt_containing(range.clone())?;
5740        let node = excerpt
5741            .buffer()
5742            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5743        let node_range = node.byte_range();
5744        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5745            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5746        } else {
5747            MultiOrSingleBufferOffsetRange::Single(node_range)
5748        };
5749        Some((node, range))
5750    }
5751
5752    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5753        let (excerpt_id, _, buffer) = self.as_singleton()?;
5754        let outline = buffer.outline(theme)?;
5755        Some(Outline::new(
5756            outline
5757                .items
5758                .into_iter()
5759                .flat_map(|item| {
5760                    Some(OutlineItem {
5761                        depth: item.depth,
5762                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5763                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5764                        text: item.text,
5765                        highlight_ranges: item.highlight_ranges,
5766                        name_ranges: item.name_ranges,
5767                        body_range: item.body_range.and_then(|body_range| {
5768                            Some(
5769                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5770                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5771                            )
5772                        }),
5773                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5774                            Some(
5775                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5776                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5777                            )
5778                        }),
5779                    })
5780                })
5781                .collect(),
5782        ))
5783    }
5784
5785    pub fn symbols_containing<T: ToOffset>(
5786        &self,
5787        offset: T,
5788        theme: Option<&SyntaxTheme>,
5789    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5790        let anchor = self.anchor_before(offset);
5791        let excerpt_id = anchor.excerpt_id;
5792        let excerpt = self.excerpt(excerpt_id)?;
5793        Some((
5794            excerpt.buffer_id,
5795            excerpt
5796                .buffer
5797                .symbols_containing(anchor.text_anchor, theme)
5798                .into_iter()
5799                .flatten()
5800                .flat_map(|item| {
5801                    Some(OutlineItem {
5802                        depth: item.depth,
5803                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5804                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5805                        text: item.text,
5806                        highlight_ranges: item.highlight_ranges,
5807                        name_ranges: item.name_ranges,
5808                        body_range: item.body_range.and_then(|body_range| {
5809                            Some(
5810                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5811                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5812                            )
5813                        }),
5814                        annotation_range: item.annotation_range.and_then(|body_range| {
5815                            Some(
5816                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5817                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5818                            )
5819                        }),
5820                    })
5821                })
5822                .collect(),
5823        ))
5824    }
5825
5826    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5827        if id == ExcerptId::min() {
5828            Locator::min_ref()
5829        } else if id == ExcerptId::max() {
5830            Locator::max_ref()
5831        } else {
5832            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5833            cursor.seek(&id, Bias::Left, &());
5834            if let Some(entry) = cursor.item() {
5835                if entry.id == id {
5836                    return &entry.locator;
5837                }
5838            }
5839            panic!("invalid excerpt id {:?}", id)
5840        }
5841    }
5842
5843    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5844    fn excerpt_locators_for_ids(
5845        &self,
5846        ids: impl IntoIterator<Item = ExcerptId>,
5847    ) -> SmallVec<[Locator; 1]> {
5848        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5849        sorted_ids.sort_unstable();
5850        let mut locators = SmallVec::new();
5851
5852        while sorted_ids.last() == Some(&ExcerptId::max()) {
5853            sorted_ids.pop();
5854            if let Some(mapping) = self.excerpt_ids.last() {
5855                locators.push(mapping.locator.clone());
5856            }
5857        }
5858
5859        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5860        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5861            sorted_ids.next();
5862            if let Some(mapping) = self.excerpt_ids.first() {
5863                locators.push(mapping.locator.clone());
5864            }
5865        }
5866
5867        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5868        for id in sorted_ids {
5869            if cursor.seek_forward(&id, Bias::Left, &()) {
5870                locators.push(cursor.item().unwrap().locator.clone());
5871            } else {
5872                panic!("invalid excerpt id {:?}", id);
5873            }
5874        }
5875
5876        locators.sort_unstable();
5877        locators
5878    }
5879
5880    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5881        Some(self.excerpt(excerpt_id)?.buffer_id)
5882    }
5883
5884    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5885        Some(&self.excerpt(excerpt_id)?.buffer)
5886    }
5887
5888    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5889        let mut cursor = self
5890            .excerpts
5891            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5892        let locator = self.excerpt_locator_for_id(excerpt_id);
5893        if cursor.seek(&Some(locator), Bias::Left, &()) {
5894            let start = cursor.start().1.clone();
5895            let end = cursor.end(&()).1;
5896            let mut diff_transforms = self
5897                .diff_transforms
5898                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5899            diff_transforms.seek(&start, Bias::Left, &());
5900            let overshoot = start.0 - diff_transforms.start().0 .0;
5901            let start = diff_transforms.start().1 .0 + overshoot;
5902            diff_transforms.seek(&end, Bias::Right, &());
5903            let overshoot = end.0 - diff_transforms.start().0 .0;
5904            let end = diff_transforms.start().1 .0 + overshoot;
5905            Some(start..end)
5906        } else {
5907            None
5908        }
5909    }
5910
5911    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5912        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5913        let locator = self.excerpt_locator_for_id(excerpt_id);
5914        if cursor.seek(&Some(locator), Bias::Left, &()) {
5915            if let Some(excerpt) = cursor.item() {
5916                return Some(excerpt.range.context.clone());
5917            }
5918        }
5919        None
5920    }
5921
5922    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5923        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5924        let locator = self.excerpt_locator_for_id(excerpt_id);
5925        cursor.seek(&Some(locator), Bias::Left, &());
5926        if let Some(excerpt) = cursor.item() {
5927            if excerpt.id == excerpt_id {
5928                return Some(excerpt);
5929            }
5930        }
5931        None
5932    }
5933
5934    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5935    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5936        let range = range.start.to_offset(self)..range.end.to_offset(self);
5937        let mut cursor = self.cursor::<usize>();
5938        cursor.seek(&range.start);
5939
5940        let start_excerpt = cursor.excerpt()?;
5941        if range.end != range.start {
5942            cursor.seek_forward(&range.end);
5943            if cursor.excerpt()?.id != start_excerpt.id {
5944                return None;
5945            }
5946        }
5947
5948        cursor.seek_to_start_of_current_excerpt();
5949        let region = cursor.region()?;
5950        let offset = region.range.start;
5951        let buffer_offset = region.buffer_range.start;
5952        let excerpt_offset = cursor.excerpts.start().clone();
5953        Some(MultiBufferExcerpt {
5954            diff_transforms: cursor.diff_transforms,
5955            excerpt: start_excerpt,
5956            offset,
5957            buffer_offset,
5958            excerpt_offset,
5959        })
5960    }
5961
5962    pub fn selections_in_range<'a>(
5963        &'a self,
5964        range: &'a Range<Anchor>,
5965        include_local: bool,
5966    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5967        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5968        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5969        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5970        cursor.seek(start_locator, Bias::Left, &());
5971        cursor
5972            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5973            .flat_map(move |excerpt| {
5974                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5975                if excerpt.id == range.start.excerpt_id {
5976                    query_range.start = range.start.text_anchor;
5977                }
5978                if excerpt.id == range.end.excerpt_id {
5979                    query_range.end = range.end.text_anchor;
5980                }
5981
5982                excerpt
5983                    .buffer
5984                    .selections_in_range(query_range, include_local)
5985                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5986                        selections.map(move |selection| {
5987                            let mut start = Anchor {
5988                                buffer_id: Some(excerpt.buffer_id),
5989                                excerpt_id: excerpt.id,
5990                                text_anchor: selection.start,
5991                                diff_base_anchor: None,
5992                            };
5993                            let mut end = Anchor {
5994                                buffer_id: Some(excerpt.buffer_id),
5995                                excerpt_id: excerpt.id,
5996                                text_anchor: selection.end,
5997                                diff_base_anchor: None,
5998                            };
5999                            if range.start.cmp(&start, self).is_gt() {
6000                                start = range.start;
6001                            }
6002                            if range.end.cmp(&end, self).is_lt() {
6003                                end = range.end;
6004                            }
6005
6006                            (
6007                                replica_id,
6008                                line_mode,
6009                                cursor_shape,
6010                                Selection {
6011                                    id: selection.id,
6012                                    start,
6013                                    end,
6014                                    reversed: selection.reversed,
6015                                    goal: selection.goal,
6016                                },
6017                            )
6018                        })
6019                    })
6020            })
6021    }
6022
6023    pub fn show_headers(&self) -> bool {
6024        self.show_headers
6025    }
6026
6027    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6028        self.diffs.get(&buffer_id)
6029    }
6030}
6031
6032#[cfg(any(test, feature = "test-support"))]
6033impl MultiBufferSnapshot {
6034    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6035        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6036        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6037        start..end
6038    }
6039
6040    #[cfg(any(test, feature = "test-support"))]
6041    fn check_invariants(&self) {
6042        let excerpts = self.excerpts.items(&());
6043        let excerpt_ids = self.excerpt_ids.items(&());
6044
6045        for (ix, excerpt) in excerpts.iter().enumerate() {
6046            if ix == 0 {
6047                if excerpt.locator <= Locator::min() {
6048                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6049                }
6050            } else if excerpt.locator <= excerpts[ix - 1].locator {
6051                panic!("excerpts are out-of-order: {:?}", excerpts);
6052            }
6053        }
6054
6055        for (ix, entry) in excerpt_ids.iter().enumerate() {
6056            if ix == 0 {
6057                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6058                    panic!("invalid first excerpt id {:?}", entry.id);
6059                }
6060            } else if entry.id <= excerpt_ids[ix - 1].id {
6061                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6062            }
6063        }
6064
6065        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6066            panic!(
6067                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6068                self.excerpts.summary().text.len,
6069                self.diff_transforms.summary().input,
6070                self.diff_transforms.items(&()),
6071            );
6072        }
6073
6074        let mut prev_transform: Option<&DiffTransform> = None;
6075        for item in self.diff_transforms.iter() {
6076            if let DiffTransform::BufferContent {
6077                summary,
6078                inserted_hunk_info,
6079            } = item
6080            {
6081                if let Some(DiffTransform::BufferContent {
6082                    inserted_hunk_info: prev_inserted_hunk_info,
6083                    ..
6084                }) = prev_transform
6085                {
6086                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6087                        panic!(
6088                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6089                            self.diff_transforms.items(&()));
6090                    }
6091                }
6092                if summary.len == 0 && !self.is_empty() {
6093                    panic!("empty buffer content transform");
6094                }
6095            }
6096            prev_transform = Some(item);
6097        }
6098    }
6099}
6100
6101impl<'a, D> MultiBufferCursor<'a, D>
6102where
6103    D: TextDimension + Ord + Sub<D, Output = D>,
6104{
6105    fn seek(&mut self, position: &D) {
6106        self.cached_region.take();
6107        self.diff_transforms
6108            .seek(&OutputDimension(*position), Bias::Right, &());
6109        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6110            self.diff_transforms.prev(&());
6111        }
6112
6113        let mut excerpt_position = self.diff_transforms.start().1 .0;
6114        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6115            let overshoot = *position - self.diff_transforms.start().0 .0;
6116            excerpt_position.add_assign(&overshoot);
6117        }
6118
6119        self.excerpts
6120            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6121        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6122            self.excerpts.prev(&());
6123        }
6124    }
6125
6126    fn seek_forward(&mut self, position: &D) {
6127        self.cached_region.take();
6128        self.diff_transforms
6129            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6130        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6131            self.diff_transforms.prev(&());
6132        }
6133
6134        let overshoot = *position - self.diff_transforms.start().0 .0;
6135        let mut excerpt_position = self.diff_transforms.start().1 .0;
6136        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6137            excerpt_position.add_assign(&overshoot);
6138        }
6139
6140        self.excerpts
6141            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6142        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6143            self.excerpts.prev(&());
6144        }
6145    }
6146
6147    fn next_excerpt(&mut self) {
6148        self.excerpts.next(&());
6149        self.seek_to_start_of_current_excerpt();
6150    }
6151
6152    fn prev_excerpt(&mut self) {
6153        self.excerpts.prev(&());
6154        self.seek_to_start_of_current_excerpt();
6155    }
6156
6157    fn seek_to_start_of_current_excerpt(&mut self) {
6158        self.cached_region.take();
6159        self.diff_transforms
6160            .seek(self.excerpts.start(), Bias::Left, &());
6161        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6162            && self.diff_transforms.start().1 < *self.excerpts.start()
6163            && self.diff_transforms.next_item().is_some()
6164        {
6165            self.diff_transforms.next(&());
6166        }
6167    }
6168
6169    fn next(&mut self) {
6170        self.cached_region.take();
6171        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6172            cmp::Ordering::Less => self.diff_transforms.next(&()),
6173            cmp::Ordering::Greater => self.excerpts.next(&()),
6174            cmp::Ordering::Equal => {
6175                self.diff_transforms.next(&());
6176                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6177                    || self.diff_transforms.item().is_none()
6178                {
6179                    self.excerpts.next(&());
6180                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6181                    self.diff_transforms.item()
6182                {
6183                    if self
6184                        .excerpts
6185                        .item()
6186                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6187                    {
6188                        self.excerpts.next(&());
6189                    }
6190                }
6191            }
6192        }
6193    }
6194
6195    fn prev(&mut self) {
6196        self.cached_region.take();
6197        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6198            cmp::Ordering::Less => self.excerpts.prev(&()),
6199            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6200            cmp::Ordering::Equal => {
6201                self.diff_transforms.prev(&());
6202                if self.diff_transforms.start().1 < *self.excerpts.start()
6203                    || self.diff_transforms.item().is_none()
6204                {
6205                    self.excerpts.prev(&());
6206                }
6207            }
6208        }
6209    }
6210
6211    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6212        if self.cached_region.is_none() {
6213            self.cached_region = self.build_region();
6214        }
6215        self.cached_region.clone()
6216    }
6217
6218    fn is_at_end_of_excerpt(&mut self) -> bool {
6219        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6220            return false;
6221        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6222            || self.diff_transforms.item().is_none()
6223        {
6224            return true;
6225        }
6226
6227        let next_transform = self.diff_transforms.next_item();
6228        next_transform.map_or(true, |next_transform| match next_transform {
6229            DiffTransform::BufferContent { .. } => true,
6230            DiffTransform::DeletedHunk { hunk_info, .. } => self
6231                .excerpts
6232                .item()
6233                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6234        })
6235    }
6236
6237    fn main_buffer_position(&self) -> Option<D> {
6238        let excerpt = self.excerpts.item()?;
6239        let buffer = &excerpt.buffer;
6240        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6241        let mut buffer_start = buffer_context_start;
6242        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6243        buffer_start.add_assign(&overshoot);
6244        Some(buffer_start)
6245    }
6246
6247    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6248        let excerpt = self.excerpts.item()?;
6249        match self.diff_transforms.item()? {
6250            DiffTransform::DeletedHunk {
6251                buffer_id,
6252                base_text_byte_range,
6253                has_trailing_newline,
6254                hunk_info,
6255                ..
6256            } => {
6257                let diff = self.diffs.get(&buffer_id)?;
6258                let buffer = diff.base_text();
6259                let mut rope_cursor = buffer.as_rope().cursor(0);
6260                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6261                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6262                let mut buffer_end = buffer_start;
6263                buffer_end.add_assign(&buffer_range_len);
6264                let start = self.diff_transforms.start().0 .0;
6265                let end = self.diff_transforms.end(&()).0 .0;
6266                return Some(MultiBufferRegion {
6267                    buffer,
6268                    excerpt,
6269                    has_trailing_newline: *has_trailing_newline,
6270                    is_main_buffer: false,
6271                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6272                        hunk_info.hunk_secondary_status,
6273                    )),
6274                    buffer_range: buffer_start..buffer_end,
6275                    range: start..end,
6276                });
6277            }
6278            DiffTransform::BufferContent {
6279                inserted_hunk_info, ..
6280            } => {
6281                let buffer = &excerpt.buffer;
6282                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6283
6284                let mut start = self.diff_transforms.start().0 .0;
6285                let mut buffer_start = buffer_context_start;
6286                if self.diff_transforms.start().1 < *self.excerpts.start() {
6287                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6288                    start.add_assign(&overshoot);
6289                } else {
6290                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6291                    buffer_start.add_assign(&overshoot);
6292                }
6293
6294                let mut end;
6295                let mut buffer_end;
6296                let has_trailing_newline;
6297                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6298                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6299                    end = self.diff_transforms.end(&()).0 .0;
6300                    buffer_end = buffer_context_start;
6301                    buffer_end.add_assign(&overshoot);
6302                    has_trailing_newline = false;
6303                } else {
6304                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6305                    end = self.diff_transforms.start().0 .0;
6306                    end.add_assign(&overshoot);
6307                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6308                    has_trailing_newline = excerpt.has_trailing_newline;
6309                };
6310
6311                Some(MultiBufferRegion {
6312                    buffer,
6313                    excerpt,
6314                    has_trailing_newline,
6315                    is_main_buffer: true,
6316                    diff_hunk_status: inserted_hunk_info
6317                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6318                    buffer_range: buffer_start..buffer_end,
6319                    range: start..end,
6320                })
6321            }
6322        }
6323    }
6324
6325    fn excerpt(&self) -> Option<&'a Excerpt> {
6326        self.excerpts.item()
6327    }
6328}
6329
6330impl History {
6331    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6332        self.transaction_depth += 1;
6333        if self.transaction_depth == 1 {
6334            let id = self.next_transaction_id.tick();
6335            self.undo_stack.push(Transaction {
6336                id,
6337                buffer_transactions: Default::default(),
6338                first_edit_at: now,
6339                last_edit_at: now,
6340                suppress_grouping: false,
6341            });
6342            Some(id)
6343        } else {
6344            None
6345        }
6346    }
6347
6348    fn end_transaction(
6349        &mut self,
6350        now: Instant,
6351        buffer_transactions: HashMap<BufferId, TransactionId>,
6352    ) -> bool {
6353        assert_ne!(self.transaction_depth, 0);
6354        self.transaction_depth -= 1;
6355        if self.transaction_depth == 0 {
6356            if buffer_transactions.is_empty() {
6357                self.undo_stack.pop();
6358                false
6359            } else {
6360                self.redo_stack.clear();
6361                let transaction = self.undo_stack.last_mut().unwrap();
6362                transaction.last_edit_at = now;
6363                for (buffer_id, transaction_id) in buffer_transactions {
6364                    transaction
6365                        .buffer_transactions
6366                        .entry(buffer_id)
6367                        .or_insert(transaction_id);
6368                }
6369                true
6370            }
6371        } else {
6372            false
6373        }
6374    }
6375
6376    fn push_transaction<'a, T>(
6377        &mut self,
6378        buffer_transactions: T,
6379        now: Instant,
6380        cx: &Context<MultiBuffer>,
6381    ) where
6382        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6383    {
6384        assert_eq!(self.transaction_depth, 0);
6385        let transaction = Transaction {
6386            id: self.next_transaction_id.tick(),
6387            buffer_transactions: buffer_transactions
6388                .into_iter()
6389                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6390                .collect(),
6391            first_edit_at: now,
6392            last_edit_at: now,
6393            suppress_grouping: false,
6394        };
6395        if !transaction.buffer_transactions.is_empty() {
6396            self.undo_stack.push(transaction);
6397            self.redo_stack.clear();
6398        }
6399    }
6400
6401    fn finalize_last_transaction(&mut self) {
6402        if let Some(transaction) = self.undo_stack.last_mut() {
6403            transaction.suppress_grouping = true;
6404        }
6405    }
6406
6407    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6408        if let Some(ix) = self
6409            .undo_stack
6410            .iter()
6411            .rposition(|transaction| transaction.id == transaction_id)
6412        {
6413            Some(self.undo_stack.remove(ix))
6414        } else if let Some(ix) = self
6415            .redo_stack
6416            .iter()
6417            .rposition(|transaction| transaction.id == transaction_id)
6418        {
6419            Some(self.redo_stack.remove(ix))
6420        } else {
6421            None
6422        }
6423    }
6424
6425    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6426        self.undo_stack
6427            .iter()
6428            .find(|transaction| transaction.id == transaction_id)
6429            .or_else(|| {
6430                self.redo_stack
6431                    .iter()
6432                    .find(|transaction| transaction.id == transaction_id)
6433            })
6434    }
6435
6436    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6437        self.undo_stack
6438            .iter_mut()
6439            .find(|transaction| transaction.id == transaction_id)
6440            .or_else(|| {
6441                self.redo_stack
6442                    .iter_mut()
6443                    .find(|transaction| transaction.id == transaction_id)
6444            })
6445    }
6446
6447    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6448        assert_eq!(self.transaction_depth, 0);
6449        if let Some(transaction) = self.undo_stack.pop() {
6450            self.redo_stack.push(transaction);
6451            self.redo_stack.last_mut()
6452        } else {
6453            None
6454        }
6455    }
6456
6457    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6458        assert_eq!(self.transaction_depth, 0);
6459        if let Some(transaction) = self.redo_stack.pop() {
6460            self.undo_stack.push(transaction);
6461            self.undo_stack.last_mut()
6462        } else {
6463            None
6464        }
6465    }
6466
6467    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6468        let ix = self
6469            .undo_stack
6470            .iter()
6471            .rposition(|transaction| transaction.id == transaction_id)?;
6472        let transaction = self.undo_stack.remove(ix);
6473        self.redo_stack.push(transaction);
6474        self.redo_stack.last()
6475    }
6476
6477    fn group(&mut self) -> Option<TransactionId> {
6478        let mut count = 0;
6479        let mut transactions = self.undo_stack.iter();
6480        if let Some(mut transaction) = transactions.next_back() {
6481            while let Some(prev_transaction) = transactions.next_back() {
6482                if !prev_transaction.suppress_grouping
6483                    && transaction.first_edit_at - prev_transaction.last_edit_at
6484                        <= self.group_interval
6485                {
6486                    transaction = prev_transaction;
6487                    count += 1;
6488                } else {
6489                    break;
6490                }
6491            }
6492        }
6493        self.group_trailing(count)
6494    }
6495
6496    fn group_until(&mut self, transaction_id: TransactionId) {
6497        let mut count = 0;
6498        for transaction in self.undo_stack.iter().rev() {
6499            if transaction.id == transaction_id {
6500                self.group_trailing(count);
6501                break;
6502            } else if transaction.suppress_grouping {
6503                break;
6504            } else {
6505                count += 1;
6506            }
6507        }
6508    }
6509
6510    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6511        let new_len = self.undo_stack.len() - n;
6512        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6513        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6514            if let Some(transaction) = transactions_to_merge.last() {
6515                last_transaction.last_edit_at = transaction.last_edit_at;
6516            }
6517            for to_merge in transactions_to_merge {
6518                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6519                    last_transaction
6520                        .buffer_transactions
6521                        .entry(*buffer_id)
6522                        .or_insert(*transaction_id);
6523                }
6524            }
6525        }
6526
6527        self.undo_stack.truncate(new_len);
6528        self.undo_stack.last().map(|t| t.id)
6529    }
6530}
6531
6532impl Excerpt {
6533    fn new(
6534        id: ExcerptId,
6535        locator: Locator,
6536        buffer_id: BufferId,
6537        buffer: BufferSnapshot,
6538        range: ExcerptRange<text::Anchor>,
6539        has_trailing_newline: bool,
6540    ) -> Self {
6541        Excerpt {
6542            id,
6543            locator,
6544            max_buffer_row: range.context.end.to_point(&buffer).row,
6545            text_summary: buffer
6546                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6547            buffer_id,
6548            buffer,
6549            range,
6550            has_trailing_newline,
6551        }
6552    }
6553
6554    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6555        let content_start = self.range.context.start.to_offset(&self.buffer);
6556        let chunks_start = content_start + range.start;
6557        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6558
6559        let footer_height = if self.has_trailing_newline
6560            && range.start <= self.text_summary.len
6561            && range.end > self.text_summary.len
6562        {
6563            1
6564        } else {
6565            0
6566        };
6567
6568        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6569
6570        ExcerptChunks {
6571            excerpt_id: self.id,
6572            content_chunks,
6573            footer_height,
6574        }
6575    }
6576
6577    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6578        let content_start = self.range.context.start.to_offset(&self.buffer);
6579        let chunks_start = content_start + range.start;
6580        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6581        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6582        excerpt_chunks.footer_height = if self.has_trailing_newline
6583            && range.start <= self.text_summary.len
6584            && range.end > self.text_summary.len
6585        {
6586            1
6587        } else {
6588            0
6589        };
6590    }
6591
6592    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6593        if text_anchor
6594            .cmp(&self.range.context.start, &self.buffer)
6595            .is_lt()
6596        {
6597            self.range.context.start
6598        } else if text_anchor
6599            .cmp(&self.range.context.end, &self.buffer)
6600            .is_gt()
6601        {
6602            self.range.context.end
6603        } else {
6604            text_anchor
6605        }
6606    }
6607
6608    fn contains(&self, anchor: &Anchor) -> bool {
6609        Some(self.buffer_id) == anchor.buffer_id
6610            && self
6611                .range
6612                .context
6613                .start
6614                .cmp(&anchor.text_anchor, &self.buffer)
6615                .is_le()
6616            && self
6617                .range
6618                .context
6619                .end
6620                .cmp(&anchor.text_anchor, &self.buffer)
6621                .is_ge()
6622    }
6623
6624    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6625    fn buffer_start_offset(&self) -> usize {
6626        self.range.context.start.to_offset(&self.buffer)
6627    }
6628
6629    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6630    fn buffer_end_offset(&self) -> usize {
6631        self.buffer_start_offset() + self.text_summary.len
6632    }
6633}
6634
6635impl<'a> MultiBufferExcerpt<'a> {
6636    pub fn id(&self) -> ExcerptId {
6637        self.excerpt.id
6638    }
6639
6640    pub fn buffer_id(&self) -> BufferId {
6641        self.excerpt.buffer_id
6642    }
6643
6644    pub fn start_anchor(&self) -> Anchor {
6645        Anchor {
6646            buffer_id: Some(self.excerpt.buffer_id),
6647            excerpt_id: self.excerpt.id,
6648            text_anchor: self.excerpt.range.context.start,
6649            diff_base_anchor: None,
6650        }
6651    }
6652
6653    pub fn end_anchor(&self) -> Anchor {
6654        Anchor {
6655            buffer_id: Some(self.excerpt.buffer_id),
6656            excerpt_id: self.excerpt.id,
6657            text_anchor: self.excerpt.range.context.end,
6658            diff_base_anchor: None,
6659        }
6660    }
6661
6662    pub fn buffer(&self) -> &'a BufferSnapshot {
6663        &self.excerpt.buffer
6664    }
6665
6666    pub fn buffer_range(&self) -> Range<usize> {
6667        self.buffer_offset
6668            ..self
6669                .excerpt
6670                .range
6671                .context
6672                .end
6673                .to_offset(&self.excerpt.buffer.text)
6674    }
6675
6676    pub fn start_offset(&self) -> usize {
6677        self.offset
6678    }
6679
6680    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6681    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6682        self.map_range_to_buffer(offset..offset).start
6683    }
6684
6685    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6686    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6687        self.diff_transforms
6688            .seek(&OutputDimension(range.start), Bias::Right, &());
6689        let start = self.map_offset_to_buffer_internal(range.start);
6690        let end = if range.end > range.start {
6691            self.diff_transforms
6692                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6693            self.map_offset_to_buffer_internal(range.end)
6694        } else {
6695            start
6696        };
6697        start..end
6698    }
6699
6700    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6701        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6702        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6703            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6704        };
6705        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6706        self.buffer_offset + offset_in_excerpt
6707    }
6708
6709    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6710    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6711        self.map_range_from_buffer(buffer_offset..buffer_offset)
6712            .start
6713    }
6714
6715    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6716    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6717        if buffer_range.start < self.buffer_offset {
6718            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6719            return buffer_range;
6720        }
6721        let overshoot = buffer_range.start - self.buffer_offset;
6722        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6723        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6724        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6725            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6726            return buffer_range;
6727        }
6728        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6729        let start = self.diff_transforms.start().0 .0 + overshoot;
6730
6731        let end = if buffer_range.end > buffer_range.start {
6732            let overshoot = buffer_range.end - self.buffer_offset;
6733            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6734            self.diff_transforms
6735                .seek_forward(&excerpt_offset, Bias::Right, &());
6736            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6737            self.diff_transforms.start().0 .0 + overshoot
6738        } else {
6739            start
6740        };
6741
6742        start..end
6743    }
6744
6745    /// Returns true if the entirety of the given range is in the buffer's excerpt
6746    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6747        range.start >= self.excerpt.buffer_start_offset()
6748            && range.end <= self.excerpt.buffer_end_offset()
6749    }
6750
6751    pub fn max_buffer_row(&self) -> u32 {
6752        self.excerpt.max_buffer_row
6753    }
6754}
6755
6756impl ExcerptId {
6757    pub fn min() -> Self {
6758        Self(0)
6759    }
6760
6761    pub fn max() -> Self {
6762        Self(usize::MAX)
6763    }
6764
6765    pub fn to_proto(&self) -> u64 {
6766        self.0 as _
6767    }
6768
6769    pub fn from_proto(proto: u64) -> Self {
6770        Self(proto as _)
6771    }
6772
6773    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6774        let a = snapshot.excerpt_locator_for_id(*self);
6775        let b = snapshot.excerpt_locator_for_id(*other);
6776        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6777    }
6778}
6779
6780impl From<ExcerptId> for usize {
6781    fn from(val: ExcerptId) -> Self {
6782        val.0
6783    }
6784}
6785
6786impl fmt::Debug for Excerpt {
6787    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6788        f.debug_struct("Excerpt")
6789            .field("id", &self.id)
6790            .field("locator", &self.locator)
6791            .field("buffer_id", &self.buffer_id)
6792            .field("range", &self.range)
6793            .field("text_summary", &self.text_summary)
6794            .field("has_trailing_newline", &self.has_trailing_newline)
6795            .finish()
6796    }
6797}
6798
6799impl sum_tree::Item for Excerpt {
6800    type Summary = ExcerptSummary;
6801
6802    fn summary(&self, _cx: &()) -> Self::Summary {
6803        let mut text = self.text_summary;
6804        if self.has_trailing_newline {
6805            text += TextSummary::from("\n");
6806        }
6807        ExcerptSummary {
6808            excerpt_id: self.id,
6809            excerpt_locator: self.locator.clone(),
6810            widest_line_number: self.max_buffer_row,
6811            text,
6812        }
6813    }
6814}
6815
6816impl sum_tree::Item for ExcerptIdMapping {
6817    type Summary = ExcerptId;
6818
6819    fn summary(&self, _cx: &()) -> Self::Summary {
6820        self.id
6821    }
6822}
6823
6824impl sum_tree::KeyedItem for ExcerptIdMapping {
6825    type Key = ExcerptId;
6826
6827    fn key(&self) -> Self::Key {
6828        self.id
6829    }
6830}
6831
6832impl DiffTransform {
6833    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6834        match self {
6835            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6836            DiffTransform::BufferContent {
6837                inserted_hunk_info, ..
6838            } => *inserted_hunk_info,
6839        }
6840    }
6841}
6842
6843impl sum_tree::Item for DiffTransform {
6844    type Summary = DiffTransformSummary;
6845
6846    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6847        match self {
6848            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6849                input: *summary,
6850                output: *summary,
6851            },
6852            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6853                input: TextSummary::default(),
6854                output: *summary,
6855            },
6856        }
6857    }
6858}
6859
6860impl DiffTransformSummary {
6861    fn excerpt_len(&self) -> ExcerptOffset {
6862        ExcerptOffset::new(self.input.len)
6863    }
6864}
6865
6866impl sum_tree::Summary for DiffTransformSummary {
6867    type Context = ();
6868
6869    fn zero(_: &Self::Context) -> Self {
6870        DiffTransformSummary {
6871            input: TextSummary::default(),
6872            output: TextSummary::default(),
6873        }
6874    }
6875
6876    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6877        self.input += &summary.input;
6878        self.output += &summary.output;
6879    }
6880}
6881
6882impl sum_tree::Summary for ExcerptId {
6883    type Context = ();
6884
6885    fn zero(_cx: &()) -> Self {
6886        Default::default()
6887    }
6888
6889    fn add_summary(&mut self, other: &Self, _: &()) {
6890        *self = *other;
6891    }
6892}
6893
6894impl sum_tree::Summary for ExcerptSummary {
6895    type Context = ();
6896
6897    fn zero(_cx: &()) -> Self {
6898        Default::default()
6899    }
6900
6901    fn add_summary(&mut self, summary: &Self, _: &()) {
6902        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6903        self.excerpt_locator = summary.excerpt_locator.clone();
6904        self.text.add_summary(&summary.text, &());
6905        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6906    }
6907}
6908
6909impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6910    fn zero(_cx: &()) -> Self {
6911        Default::default()
6912    }
6913
6914    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6915        self.value += summary.text.len;
6916    }
6917}
6918
6919impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6920    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6921        Ord::cmp(&self.value, &cursor_location.text.len)
6922    }
6923}
6924
6925impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6926    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6927        Ord::cmp(&Some(self), cursor_location)
6928    }
6929}
6930
6931impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6932    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6933        Ord::cmp(self, &cursor_location.excerpt_locator)
6934    }
6935}
6936
6937impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6938    fn zero(_cx: &()) -> Self {
6939        Default::default()
6940    }
6941
6942    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6943        self.value += summary.text.lines;
6944    }
6945}
6946
6947impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6948    for ExcerptDimension<D>
6949{
6950    fn zero(_: &()) -> Self {
6951        ExcerptDimension(D::default())
6952    }
6953
6954    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6955        self.0.add_assign(&D::from_text_summary(&summary.text))
6956    }
6957}
6958
6959impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6960    fn zero(_cx: &()) -> Self {
6961        Default::default()
6962    }
6963
6964    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6965        *self = Some(&summary.excerpt_locator);
6966    }
6967}
6968
6969impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6970    fn zero(_cx: &()) -> Self {
6971        Default::default()
6972    }
6973
6974    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6975        *self = Some(summary.excerpt_id);
6976    }
6977}
6978
6979#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6980struct ExcerptDimension<T>(T);
6981
6982#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6983struct OutputDimension<T>(T);
6984
6985impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6986    fn zero(_: &()) -> Self {
6987        ExcerptOffset::new(0)
6988    }
6989
6990    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6991        self.value += summary.input.len;
6992    }
6993}
6994
6995impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6996    fn zero(_: &()) -> Self {
6997        ExcerptPoint::new(0, 0)
6998    }
6999
7000    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7001        self.value += summary.input.lines;
7002    }
7003}
7004
7005impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7006    for ExcerptDimension<D>
7007{
7008    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7009        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7010    }
7011}
7012
7013impl<D: TextDimension + Ord>
7014    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7015    for ExcerptDimension<D>
7016{
7017    fn cmp(
7018        &self,
7019        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7020        _: &(),
7021    ) -> cmp::Ordering {
7022        Ord::cmp(&self.0, &cursor_location.1 .0)
7023    }
7024}
7025
7026impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7027    fn zero(_: &()) -> Self {
7028        ExcerptDimension(D::default())
7029    }
7030
7031    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7032        self.0.add_assign(&D::from_text_summary(&summary.input))
7033    }
7034}
7035
7036impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7037    fn zero(_: &()) -> Self {
7038        OutputDimension(D::default())
7039    }
7040
7041    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7042        self.0.add_assign(&D::from_text_summary(&summary.output))
7043    }
7044}
7045
7046impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7047    fn zero(_: &()) -> Self {
7048        TextSummary::default()
7049    }
7050
7051    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7052        *self += summary.output
7053    }
7054}
7055
7056impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7057    fn zero(_: &()) -> Self {
7058        0
7059    }
7060
7061    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7062        *self += summary.output.len
7063    }
7064}
7065
7066impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7067    fn zero(_: &()) -> Self {
7068        Point::new(0, 0)
7069    }
7070
7071    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7072        *self += summary.output.lines
7073    }
7074}
7075
7076impl MultiBufferRows<'_> {
7077    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7078        self.point = Point::new(row, 0);
7079        self.cursor.seek(&self.point);
7080    }
7081}
7082
7083impl Iterator for MultiBufferRows<'_> {
7084    type Item = RowInfo;
7085
7086    fn next(&mut self) -> Option<Self::Item> {
7087        if self.is_empty && self.point.row == 0 {
7088            self.point += Point::new(1, 0);
7089            return Some(RowInfo {
7090                buffer_id: None,
7091                buffer_row: Some(0),
7092                multibuffer_row: Some(MultiBufferRow(0)),
7093                diff_status: None,
7094            });
7095        }
7096
7097        let mut region = self.cursor.region()?;
7098        while self.point >= region.range.end {
7099            self.cursor.next();
7100            if let Some(next_region) = self.cursor.region() {
7101                region = next_region;
7102            } else {
7103                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7104                    let multibuffer_row = MultiBufferRow(self.point.row);
7105                    self.point += Point::new(1, 0);
7106                    let last_excerpt = self
7107                        .cursor
7108                        .excerpts
7109                        .item()
7110                        .or(self.cursor.excerpts.prev_item())?;
7111                    let last_row = last_excerpt
7112                        .range
7113                        .context
7114                        .end
7115                        .to_point(&last_excerpt.buffer)
7116                        .row;
7117                    return Some(RowInfo {
7118                        buffer_id: Some(last_excerpt.buffer_id),
7119                        buffer_row: Some(last_row),
7120                        multibuffer_row: Some(multibuffer_row),
7121                        diff_status: None,
7122                    });
7123                } else {
7124                    return None;
7125                }
7126            };
7127        }
7128
7129        let overshoot = self.point - region.range.start;
7130        let buffer_point = region.buffer_range.start + overshoot;
7131        let result = Some(RowInfo {
7132            buffer_id: Some(region.buffer.remote_id()),
7133            buffer_row: Some(buffer_point.row),
7134            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7135            diff_status: region
7136                .diff_hunk_status
7137                .filter(|_| self.point < region.range.end),
7138        });
7139        self.point += Point::new(1, 0);
7140        result
7141    }
7142}
7143
7144impl<'a> MultiBufferChunks<'a> {
7145    pub fn offset(&self) -> usize {
7146        self.range.start
7147    }
7148
7149    pub fn seek(&mut self, range: Range<usize>) {
7150        self.diff_transforms.seek(&range.end, Bias::Right, &());
7151        let mut excerpt_end = self.diff_transforms.start().1;
7152        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7153            let overshoot = range.end - self.diff_transforms.start().0;
7154            excerpt_end.value += overshoot;
7155        }
7156
7157        self.diff_transforms.seek(&range.start, Bias::Right, &());
7158        let mut excerpt_start = self.diff_transforms.start().1;
7159        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7160            let overshoot = range.start - self.diff_transforms.start().0;
7161            excerpt_start.value += overshoot;
7162        }
7163
7164        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7165        self.buffer_chunk.take();
7166        self.range = range;
7167    }
7168
7169    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7170        self.excerpt_offset_range = new_range.clone();
7171        self.excerpts.seek(&new_range.start, Bias::Right, &());
7172        if let Some(excerpt) = self.excerpts.item() {
7173            let excerpt_start = *self.excerpts.start();
7174            if let Some(excerpt_chunks) = self
7175                .excerpt_chunks
7176                .as_mut()
7177                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7178            {
7179                excerpt.seek_chunks(
7180                    excerpt_chunks,
7181                    (self.excerpt_offset_range.start - excerpt_start).value
7182                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7183                );
7184            } else {
7185                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7186                    (self.excerpt_offset_range.start - excerpt_start).value
7187                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7188                    self.language_aware,
7189                ));
7190            }
7191        } else {
7192            self.excerpt_chunks = None;
7193        }
7194    }
7195
7196    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7197        loop {
7198            if self.excerpt_offset_range.is_empty() {
7199                return None;
7200            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7201                self.excerpt_offset_range.start.value += chunk.text.len();
7202                return Some(chunk);
7203            } else {
7204                self.excerpts.next(&());
7205                let excerpt = self.excerpts.item()?;
7206                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7207                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7208                    self.language_aware,
7209                ));
7210            }
7211        }
7212    }
7213}
7214
7215impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7216    type Item = &'a str;
7217
7218    fn next(&mut self) -> Option<Self::Item> {
7219        let mut region = self.cursor.region()?;
7220        if self.offset == region.range.start {
7221            self.cursor.prev();
7222            region = self.cursor.region()?;
7223            let start_overshoot = self.start.saturating_sub(region.range.start);
7224            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7225                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7226            ));
7227        }
7228
7229        if self.offset == region.range.end && region.has_trailing_newline {
7230            self.offset -= 1;
7231            Some("\n")
7232        } else {
7233            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7234            self.offset -= chunk.len();
7235            Some(chunk)
7236        }
7237    }
7238}
7239
7240impl<'a> Iterator for MultiBufferChunks<'a> {
7241    type Item = Chunk<'a>;
7242
7243    fn next(&mut self) -> Option<Chunk<'a>> {
7244        if self.range.start >= self.range.end {
7245            return None;
7246        }
7247        if self.range.start == self.diff_transforms.end(&()).0 {
7248            self.diff_transforms.next(&());
7249        }
7250
7251        let diff_transform_start = self.diff_transforms.start().0;
7252        let diff_transform_end = self.diff_transforms.end(&()).0;
7253        debug_assert!(self.range.start < diff_transform_end);
7254
7255        let diff_transform = self.diff_transforms.item()?;
7256        match diff_transform {
7257            DiffTransform::BufferContent { .. } => {
7258                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7259                    chunk
7260                } else {
7261                    let chunk = self.next_excerpt_chunk().unwrap();
7262                    self.buffer_chunk.insert(chunk)
7263                };
7264
7265                let chunk_end = self.range.start + chunk.text.len();
7266                let diff_transform_end = diff_transform_end.min(self.range.end);
7267
7268                if diff_transform_end < chunk_end {
7269                    let (before, after) =
7270                        chunk.text.split_at(diff_transform_end - self.range.start);
7271                    self.range.start = diff_transform_end;
7272                    chunk.text = after;
7273                    Some(Chunk {
7274                        text: before,
7275                        ..chunk.clone()
7276                    })
7277                } else {
7278                    self.range.start = chunk_end;
7279                    self.buffer_chunk.take()
7280                }
7281            }
7282            DiffTransform::DeletedHunk {
7283                buffer_id,
7284                base_text_byte_range,
7285                has_trailing_newline,
7286                ..
7287            } => {
7288                let base_text_start =
7289                    base_text_byte_range.start + self.range.start - diff_transform_start;
7290                let base_text_end =
7291                    base_text_byte_range.start + self.range.end - diff_transform_start;
7292                let base_text_end = base_text_end.min(base_text_byte_range.end);
7293
7294                let mut chunks = if let Some((_, mut chunks)) = self
7295                    .diff_base_chunks
7296                    .take()
7297                    .filter(|(id, _)| id == buffer_id)
7298                {
7299                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7300                    {
7301                        chunks.seek(base_text_start..base_text_end);
7302                    }
7303                    chunks
7304                } else {
7305                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7306                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7307                };
7308
7309                let chunk = if let Some(chunk) = chunks.next() {
7310                    self.range.start += chunk.text.len();
7311                    self.diff_base_chunks = Some((*buffer_id, chunks));
7312                    chunk
7313                } else {
7314                    debug_assert!(has_trailing_newline);
7315                    self.range.start += "\n".len();
7316                    Chunk {
7317                        text: "\n",
7318                        ..Default::default()
7319                    }
7320                };
7321                Some(chunk)
7322            }
7323        }
7324    }
7325}
7326
7327impl MultiBufferBytes<'_> {
7328    fn consume(&mut self, len: usize) {
7329        self.range.start += len;
7330        self.chunk = &self.chunk[len..];
7331
7332        if !self.range.is_empty() && self.chunk.is_empty() {
7333            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7334                self.chunk = chunk;
7335            } else if self.has_trailing_newline {
7336                self.has_trailing_newline = false;
7337                self.chunk = b"\n";
7338            } else {
7339                self.cursor.next();
7340                if let Some(region) = self.cursor.region() {
7341                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7342                        region.buffer_range.start
7343                            ..(region.buffer_range.start + self.range.end - region.range.start)
7344                                .min(region.buffer_range.end),
7345                    );
7346                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7347                    self.excerpt_bytes = Some(excerpt_bytes);
7348                    self.has_trailing_newline =
7349                        region.has_trailing_newline && self.range.end >= region.range.end;
7350                    if self.chunk.is_empty() && self.has_trailing_newline {
7351                        self.has_trailing_newline = false;
7352                        self.chunk = b"\n";
7353                    }
7354                }
7355            }
7356        }
7357    }
7358}
7359
7360impl<'a> Iterator for MultiBufferBytes<'a> {
7361    type Item = &'a [u8];
7362
7363    fn next(&mut self) -> Option<Self::Item> {
7364        let chunk = self.chunk;
7365        if chunk.is_empty() {
7366            None
7367        } else {
7368            self.consume(chunk.len());
7369            Some(chunk)
7370        }
7371    }
7372}
7373
7374impl io::Read for MultiBufferBytes<'_> {
7375    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7376        let len = cmp::min(buf.len(), self.chunk.len());
7377        buf[..len].copy_from_slice(&self.chunk[..len]);
7378        if len > 0 {
7379            self.consume(len);
7380        }
7381        Ok(len)
7382    }
7383}
7384
7385impl io::Read for ReversedMultiBufferBytes<'_> {
7386    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7387        let len = cmp::min(buf.len(), self.chunk.len());
7388        buf[..len].copy_from_slice(&self.chunk[..len]);
7389        buf[..len].reverse();
7390        if len > 0 {
7391            self.range.end -= len;
7392            self.chunk = &self.chunk[..self.chunk.len() - len];
7393            if !self.range.is_empty() && self.chunk.is_empty() {
7394                if let Some(chunk) = self.chunks.next() {
7395                    self.chunk = chunk.as_bytes();
7396                }
7397            }
7398        }
7399        Ok(len)
7400    }
7401}
7402
7403impl<'a> Iterator for ExcerptChunks<'a> {
7404    type Item = Chunk<'a>;
7405
7406    fn next(&mut self) -> Option<Self::Item> {
7407        if let Some(chunk) = self.content_chunks.next() {
7408            return Some(chunk);
7409        }
7410
7411        if self.footer_height > 0 {
7412            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7413            self.footer_height = 0;
7414            return Some(Chunk {
7415                text,
7416                ..Default::default()
7417            });
7418        }
7419
7420        None
7421    }
7422}
7423
7424impl ToOffset for Point {
7425    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7426        snapshot.point_to_offset(*self)
7427    }
7428}
7429
7430impl ToOffset for usize {
7431    #[track_caller]
7432    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7433        assert!(*self <= snapshot.len(), "offset is out of range");
7434        *self
7435    }
7436}
7437
7438impl ToOffset for OffsetUtf16 {
7439    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7440        snapshot.offset_utf16_to_offset(*self)
7441    }
7442}
7443
7444impl ToOffset for PointUtf16 {
7445    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7446        snapshot.point_utf16_to_offset(*self)
7447    }
7448}
7449
7450impl ToOffsetUtf16 for OffsetUtf16 {
7451    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7452        *self
7453    }
7454}
7455
7456impl ToOffsetUtf16 for usize {
7457    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7458        snapshot.offset_to_offset_utf16(*self)
7459    }
7460}
7461
7462impl ToPoint for usize {
7463    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7464        snapshot.offset_to_point(*self)
7465    }
7466}
7467
7468impl ToPoint for Point {
7469    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7470        *self
7471    }
7472}
7473
7474impl ToPointUtf16 for usize {
7475    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7476        snapshot.offset_to_point_utf16(*self)
7477    }
7478}
7479
7480impl ToPointUtf16 for Point {
7481    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7482        snapshot.point_to_point_utf16(*self)
7483    }
7484}
7485
7486impl ToPointUtf16 for PointUtf16 {
7487    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7488        *self
7489    }
7490}
7491
7492impl From<ExcerptId> for EntityId {
7493    fn from(id: ExcerptId) -> Self {
7494        EntityId::from(id.0 as u64)
7495    }
7496}
7497
7498pub fn build_excerpt_ranges<T>(
7499    buffer: &BufferSnapshot,
7500    ranges: &[Range<T>],
7501    context_line_count: u32,
7502) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7503where
7504    T: text::ToPoint,
7505{
7506    let max_point = buffer.max_point();
7507    let mut range_counts = Vec::new();
7508    let mut excerpt_ranges = Vec::new();
7509    let mut range_iter = ranges
7510        .iter()
7511        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7512        .peekable();
7513    while let Some(range) = range_iter.next() {
7514        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7515        let row = (range.end.row + context_line_count).min(max_point.row);
7516        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7517
7518        let mut ranges_in_excerpt = 1;
7519
7520        while let Some(next_range) = range_iter.peek() {
7521            if next_range.start.row <= excerpt_end.row + context_line_count {
7522                let row = (next_range.end.row + context_line_count).min(max_point.row);
7523                excerpt_end = Point::new(row, buffer.line_len(row));
7524
7525                ranges_in_excerpt += 1;
7526                range_iter.next();
7527            } else {
7528                break;
7529            }
7530        }
7531
7532        excerpt_ranges.push(ExcerptRange {
7533            context: excerpt_start..excerpt_end,
7534            primary: Some(range),
7535        });
7536        range_counts.push(ranges_in_excerpt);
7537    }
7538
7539    (excerpt_ranges, range_counts)
7540}