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_start_column: 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_start_columns = match &mut autoindent_mode {
 771                Some(AutoindentMode::Block {
 772                    original_start_columns,
 773                }) => mem::take(original_start_columns),
 774                _ => Default::default(),
 775            };
 776
 777            let (buffer_edits, edited_excerpt_ids) =
 778                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_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_start_column: 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_start_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_start_columns: 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_start_columns: &[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_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 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_start_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_start_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_start_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_start_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 point = point.to_point(&snapshot);
2006        let mut cursor = snapshot.cursor::<Point>();
2007        cursor.seek(&point);
2008
2009        cursor.region().and_then(|region| {
2010            if !region.is_main_buffer {
2011                return None;
2012            }
2013
2014            let overshoot = point - region.range.start;
2015            let buffer_point = region.buffer_range.start + overshoot;
2016            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
2017                .buffer
2018                .clone();
2019            Some((buffer, buffer_point, region.excerpt.id))
2020        })
2021    }
2022
2023    pub fn buffer_point_to_anchor(
2024        &self,
2025        buffer: &Entity<Buffer>,
2026        point: Point,
2027        cx: &App,
2028    ) -> Option<Anchor> {
2029        let mut found = None;
2030        let snapshot = buffer.read(cx).snapshot();
2031        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2032            let start = range.context.start.to_point(&snapshot);
2033            let end = range.context.end.to_point(&snapshot);
2034            if start <= point && point < end {
2035                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2036                break;
2037            }
2038            if point < start {
2039                found = Some((start, excerpt_id));
2040            }
2041            if point > end {
2042                found = Some((end, excerpt_id));
2043            }
2044        }
2045
2046        found.map(|(point, excerpt_id)| {
2047            let text_anchor = snapshot.anchor_after(point);
2048            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2049        })
2050    }
2051
2052    pub fn remove_excerpts(
2053        &mut self,
2054        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2055        cx: &mut Context<Self>,
2056    ) {
2057        self.sync(cx);
2058        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2059        if ids.is_empty() {
2060            return;
2061        }
2062
2063        let mut buffers = self.buffers.borrow_mut();
2064        let mut snapshot = self.snapshot.borrow_mut();
2065        let mut new_excerpts = SumTree::default();
2066        let mut cursor = snapshot
2067            .excerpts
2068            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2069        let mut edits = Vec::new();
2070        let mut excerpt_ids = ids.iter().copied().peekable();
2071        let mut removed_buffer_ids = Vec::new();
2072
2073        while let Some(excerpt_id) = excerpt_ids.next() {
2074            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2075            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2076            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2077
2078            if let Some(mut excerpt) = cursor.item() {
2079                if excerpt.id != excerpt_id {
2080                    continue;
2081                }
2082                let mut old_start = cursor.start().1;
2083
2084                // Skip over the removed excerpt.
2085                'remove_excerpts: loop {
2086                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2087                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2088                        if buffer_state.excerpts.is_empty() {
2089                            log::debug!(
2090                                "removing buffer and diff for buffer {}",
2091                                excerpt.buffer_id
2092                            );
2093                            buffers.remove(&excerpt.buffer_id);
2094                            removed_buffer_ids.push(excerpt.buffer_id);
2095                        }
2096                    }
2097                    cursor.next(&());
2098
2099                    // Skip over any subsequent excerpts that are also removed.
2100                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2101                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2102                        if let Some(next_excerpt) = cursor.item() {
2103                            if next_excerpt.locator == *next_locator {
2104                                excerpt_ids.next();
2105                                excerpt = next_excerpt;
2106                                continue 'remove_excerpts;
2107                            }
2108                        }
2109                    }
2110
2111                    break;
2112                }
2113
2114                // When removing the last excerpt, remove the trailing newline from
2115                // the previous excerpt.
2116                if cursor.item().is_none() && old_start.value > 0 {
2117                    old_start.value -= 1;
2118                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2119                }
2120
2121                // Push an edit for the removal of this run of excerpts.
2122                let old_end = cursor.start().1;
2123                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2124                edits.push(Edit {
2125                    old: old_start..old_end,
2126                    new: new_start..new_start,
2127                });
2128            }
2129        }
2130        let suffix = cursor.suffix(&());
2131        let changed_trailing_excerpt = suffix.is_empty();
2132        new_excerpts.append(suffix, &());
2133        drop(cursor);
2134        snapshot.excerpts = new_excerpts;
2135        for buffer_id in removed_buffer_ids {
2136            self.diffs.remove(&buffer_id);
2137            snapshot.diffs.remove(&buffer_id);
2138        }
2139
2140        if changed_trailing_excerpt {
2141            snapshot.trailing_excerpt_update_count += 1;
2142        }
2143
2144        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2145        cx.emit(Event::Edited {
2146            singleton_buffer_edited: false,
2147            edited_buffer: None,
2148        });
2149        cx.emit(Event::ExcerptsRemoved { ids });
2150        cx.notify();
2151    }
2152
2153    pub fn wait_for_anchors<'a>(
2154        &self,
2155        anchors: impl 'a + Iterator<Item = Anchor>,
2156        cx: &mut Context<Self>,
2157    ) -> impl 'static + Future<Output = Result<()>> {
2158        let borrow = self.buffers.borrow();
2159        let mut error = None;
2160        let mut futures = Vec::new();
2161        for anchor in anchors {
2162            if let Some(buffer_id) = anchor.buffer_id {
2163                if let Some(buffer) = borrow.get(&buffer_id) {
2164                    buffer.buffer.update(cx, |buffer, _| {
2165                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2166                    });
2167                } else {
2168                    error = Some(anyhow!(
2169                        "buffer {buffer_id} is not part of this multi-buffer"
2170                    ));
2171                    break;
2172                }
2173            }
2174        }
2175        async move {
2176            if let Some(error) = error {
2177                Err(error)?;
2178            }
2179            for future in futures {
2180                future.await?;
2181            }
2182            Ok(())
2183        }
2184    }
2185
2186    pub fn text_anchor_for_position<T: ToOffset>(
2187        &self,
2188        position: T,
2189        cx: &App,
2190    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2191        let snapshot = self.read(cx);
2192        let anchor = snapshot.anchor_before(position);
2193        let buffer = self
2194            .buffers
2195            .borrow()
2196            .get(&anchor.buffer_id?)?
2197            .buffer
2198            .clone();
2199        Some((buffer, anchor.text_anchor))
2200    }
2201
2202    fn on_buffer_event(
2203        &mut self,
2204        buffer: Entity<Buffer>,
2205        event: &language::BufferEvent,
2206        cx: &mut Context<Self>,
2207    ) {
2208        cx.emit(match event {
2209            language::BufferEvent::Edited => Event::Edited {
2210                singleton_buffer_edited: true,
2211                edited_buffer: Some(buffer.clone()),
2212            },
2213            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2214            language::BufferEvent::Saved => Event::Saved,
2215            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2216            language::BufferEvent::Reloaded => Event::Reloaded,
2217            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2218            language::BufferEvent::LanguageChanged => {
2219                Event::LanguageChanged(buffer.read(cx).remote_id())
2220            }
2221            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2222            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2223            language::BufferEvent::Closed => Event::Closed,
2224            language::BufferEvent::Discarded => Event::Discarded,
2225            language::BufferEvent::CapabilityChanged => {
2226                self.capability = buffer.read(cx).capability();
2227                Event::CapabilityChanged
2228            }
2229            language::BufferEvent::Operation { .. } => return,
2230        });
2231    }
2232
2233    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2234        self.sync(cx);
2235        let mut snapshot = self.snapshot.borrow_mut();
2236        let diff = diff.read(cx);
2237        let buffer_id = diff.buffer_id;
2238        let diff = diff.snapshot(cx);
2239        snapshot.diffs.insert(buffer_id, diff);
2240    }
2241
2242    fn buffer_diff_changed(
2243        &mut self,
2244        diff: Entity<BufferDiff>,
2245        range: Range<text::Anchor>,
2246        cx: &mut Context<Self>,
2247    ) {
2248        self.sync(cx);
2249        self.buffer_changed_since_sync.replace(true);
2250
2251        let diff = diff.read(cx);
2252        let buffer_id = diff.buffer_id;
2253        let buffers = self.buffers.borrow();
2254        let Some(buffer_state) = buffers.get(&buffer_id) else {
2255            return;
2256        };
2257
2258        let buffer = buffer_state.buffer.read(cx);
2259        let diff_change_range = range.to_offset(buffer);
2260
2261        let new_diff = diff.snapshot(cx);
2262        let mut snapshot = self.snapshot.borrow_mut();
2263        let base_text_changed = snapshot
2264            .diffs
2265            .get(&buffer_id)
2266            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2267
2268        snapshot.diffs.insert(buffer_id, new_diff);
2269
2270        let mut excerpt_edits = Vec::new();
2271        for locator in &buffer_state.excerpts {
2272            let mut cursor = snapshot
2273                .excerpts
2274                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2275            cursor.seek_forward(&Some(locator), Bias::Left, &());
2276            if let Some(excerpt) = cursor.item() {
2277                if excerpt.locator == *locator {
2278                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2279                    if diff_change_range.end < excerpt_buffer_range.start
2280                        || diff_change_range.start > excerpt_buffer_range.end
2281                    {
2282                        continue;
2283                    }
2284                    let excerpt_start = cursor.start().1;
2285                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2286                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2287                        diff_change_range
2288                            .start
2289                            .saturating_sub(excerpt_buffer_range.start),
2290                    );
2291                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2292                        diff_change_range
2293                            .end
2294                            .saturating_sub(excerpt_buffer_range.start),
2295                    );
2296                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2297                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2298                    excerpt_edits.push(Edit {
2299                        old: edit_start..edit_end,
2300                        new: edit_start..edit_end,
2301                    });
2302                }
2303            }
2304        }
2305
2306        self.sync_diff_transforms(
2307            &mut snapshot,
2308            excerpt_edits,
2309            DiffChangeKind::DiffUpdated {
2310                base_changed: base_text_changed,
2311            },
2312        );
2313        cx.emit(Event::Edited {
2314            singleton_buffer_edited: false,
2315            edited_buffer: None,
2316        });
2317    }
2318
2319    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2320        self.buffers
2321            .borrow()
2322            .values()
2323            .map(|state| state.buffer.clone())
2324            .collect()
2325    }
2326
2327    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2328        self.buffers
2329            .borrow()
2330            .get(&buffer_id)
2331            .map(|state| state.buffer.clone())
2332    }
2333
2334    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2335        self.point_to_buffer_offset(point, cx)
2336            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2337    }
2338
2339    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2340        let mut language = None;
2341        let mut file = None;
2342        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2343            let buffer = buffer.read(cx);
2344            language = buffer.language_at(offset);
2345            file = buffer.file();
2346        }
2347        language_settings(language.map(|l| l.name()), file, cx)
2348    }
2349
2350    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2351        self.buffers
2352            .borrow()
2353            .values()
2354            .for_each(|state| f(&state.buffer))
2355    }
2356
2357    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2358        if let Some(title) = self.title.as_ref() {
2359            return title.into();
2360        }
2361
2362        if let Some(buffer) = self.as_singleton() {
2363            if let Some(file) = buffer.read(cx).file() {
2364                return file.file_name(cx).to_string_lossy();
2365            }
2366        }
2367
2368        "untitled".into()
2369    }
2370
2371    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2372        self.title = Some(title);
2373        cx.notify();
2374    }
2375
2376    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2377    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2378        for buffer_state in self.buffers.borrow().values() {
2379            buffer_state
2380                .buffer
2381                .update(cx, |buffer, _cx| buffer.refresh_preview());
2382        }
2383    }
2384
2385    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2386    pub fn preserve_preview(&self, cx: &App) -> bool {
2387        self.buffers
2388            .borrow()
2389            .values()
2390            .all(|state| state.buffer.read(cx).preserve_preview())
2391    }
2392
2393    #[cfg(any(test, feature = "test-support"))]
2394    pub fn is_parsing(&self, cx: &App) -> bool {
2395        self.as_singleton().unwrap().read(cx).is_parsing()
2396    }
2397
2398    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2399        let buffer_id = diff.read(cx).buffer_id;
2400        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2401        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2402    }
2403
2404    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2405        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2406    }
2407
2408    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2409        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2410    }
2411
2412    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2413        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2414    }
2415
2416    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2417        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2418        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2419    }
2420
2421    pub fn all_diff_hunks_expanded(&self) -> bool {
2422        self.snapshot.borrow().all_diff_hunks_expanded
2423    }
2424
2425    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2426        self.read(cx)
2427            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2428            .nth(1)
2429            .is_some()
2430    }
2431
2432    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2433        let snapshot = self.read(cx);
2434        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2435        let offset_range = range.to_offset(&snapshot);
2436        cursor.seek(&offset_range.start, Bias::Left, &());
2437        while let Some(item) = cursor.item() {
2438            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2439                break;
2440            }
2441            if item.hunk_info().is_some() {
2442                return true;
2443            }
2444            cursor.next(&());
2445        }
2446        false
2447    }
2448
2449    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2450        let snapshot = self.read(cx);
2451        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2452        for range in ranges {
2453            let range = range.to_point(&snapshot);
2454            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2455            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2456            let start = start.saturating_sub(1);
2457            let end = snapshot.len().min(end + 1);
2458            cursor.seek(&start, Bias::Right, &());
2459            while let Some(item) = cursor.item() {
2460                if *cursor.start() >= end {
2461                    break;
2462                }
2463                if item.hunk_info().is_some() {
2464                    return true;
2465                }
2466                cursor.next(&());
2467            }
2468        }
2469        false
2470    }
2471
2472    pub fn expand_or_collapse_diff_hunks_inner(
2473        &mut self,
2474        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2475        expand: bool,
2476        cx: &mut Context<Self>,
2477    ) {
2478        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2479            return;
2480        }
2481        self.sync(cx);
2482        let mut snapshot = self.snapshot.borrow_mut();
2483        let mut excerpt_edits = Vec::new();
2484        for (range, end_excerpt_id) in ranges {
2485            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2486                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2487                    continue;
2488                }
2489                let start = Anchor::in_buffer(
2490                    diff_hunk.excerpt_id,
2491                    diff_hunk.buffer_id,
2492                    diff_hunk.buffer_range.start,
2493                );
2494                let end = Anchor::in_buffer(
2495                    diff_hunk.excerpt_id,
2496                    diff_hunk.buffer_id,
2497                    diff_hunk.buffer_range.end,
2498                );
2499                let start = snapshot.excerpt_offset_for_anchor(&start);
2500                let end = snapshot.excerpt_offset_for_anchor(&end);
2501                excerpt_edits.push(text::Edit {
2502                    old: start..end,
2503                    new: start..end,
2504                });
2505            }
2506        }
2507
2508        self.sync_diff_transforms(
2509            &mut snapshot,
2510            excerpt_edits,
2511            DiffChangeKind::ExpandOrCollapseHunks { expand },
2512        );
2513        cx.emit(Event::DiffHunksToggled);
2514        cx.emit(Event::Edited {
2515            singleton_buffer_edited: false,
2516            edited_buffer: None,
2517        });
2518    }
2519
2520    pub fn expand_or_collapse_diff_hunks(
2521        &mut self,
2522        ranges: Vec<Range<Anchor>>,
2523        expand: bool,
2524        cx: &mut Context<Self>,
2525    ) {
2526        let snapshot = self.snapshot.borrow().clone();
2527        let ranges = ranges.iter().map(move |range| {
2528            let end_excerpt_id = range.end.excerpt_id;
2529            let range = range.to_point(&snapshot);
2530            let mut peek_end = range.end;
2531            if range.end.row < snapshot.max_row().0 {
2532                peek_end = Point::new(range.end.row + 1, 0);
2533            };
2534            (range.start..peek_end, end_excerpt_id)
2535        });
2536        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2537    }
2538
2539    pub fn resize_excerpt(
2540        &mut self,
2541        id: ExcerptId,
2542        range: Range<text::Anchor>,
2543        cx: &mut Context<Self>,
2544    ) {
2545        self.sync(cx);
2546
2547        let mut snapshot = self.snapshot.borrow_mut();
2548        let locator = snapshot.excerpt_locator_for_id(id);
2549        let mut new_excerpts = SumTree::default();
2550        let mut cursor = snapshot
2551            .excerpts
2552            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2553        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2554
2555        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2556        new_excerpts.append(prefix, &());
2557
2558        let mut excerpt = cursor.item().unwrap().clone();
2559        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2560
2561        excerpt.range.context.start = range.start;
2562        excerpt.range.context.end = range.end;
2563        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2564
2565        excerpt.text_summary = excerpt
2566            .buffer
2567            .text_summary_for_range(excerpt.range.context.clone());
2568
2569        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2570        let old_start_offset = cursor.start().1;
2571        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2572        let edit = Edit {
2573            old: old_start_offset..old_start_offset + old_text_len,
2574            new: new_start_offset..new_start_offset + new_text_len,
2575        };
2576
2577        if let Some(last_edit) = edits.last_mut() {
2578            if last_edit.old.end == edit.old.start {
2579                last_edit.old.end = edit.old.end;
2580                last_edit.new.end = edit.new.end;
2581            } else {
2582                edits.push(edit);
2583            }
2584        } else {
2585            edits.push(edit);
2586        }
2587
2588        new_excerpts.push(excerpt, &());
2589
2590        cursor.next(&());
2591
2592        new_excerpts.append(cursor.suffix(&()), &());
2593
2594        drop(cursor);
2595        snapshot.excerpts = new_excerpts;
2596
2597        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2598        cx.emit(Event::Edited {
2599            singleton_buffer_edited: false,
2600            edited_buffer: None,
2601        });
2602        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2603        cx.notify();
2604    }
2605
2606    pub fn expand_excerpts(
2607        &mut self,
2608        ids: impl IntoIterator<Item = ExcerptId>,
2609        line_count: u32,
2610        direction: ExpandExcerptDirection,
2611        cx: &mut Context<Self>,
2612    ) {
2613        if line_count == 0 {
2614            return;
2615        }
2616        self.sync(cx);
2617        let mut snapshot = self.snapshot.borrow_mut();
2618
2619        let ids = ids.into_iter().collect::<Vec<_>>();
2620        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2621        let mut new_excerpts = SumTree::default();
2622        let mut cursor = snapshot
2623            .excerpts
2624            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2625        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2626
2627        for locator in &locators {
2628            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2629            new_excerpts.append(prefix, &());
2630
2631            let mut excerpt = cursor.item().unwrap().clone();
2632            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2633
2634            let up_line_count = if direction.should_expand_up() {
2635                line_count
2636            } else {
2637                0
2638            };
2639
2640            let start_row = excerpt
2641                .range
2642                .context
2643                .start
2644                .to_point(&excerpt.buffer)
2645                .row
2646                .saturating_sub(up_line_count);
2647            let start_point = Point::new(start_row, 0);
2648            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2649
2650            let down_line_count = if direction.should_expand_down() {
2651                line_count
2652            } else {
2653                0
2654            };
2655
2656            let mut end_point = excerpt.buffer.clip_point(
2657                excerpt.range.context.end.to_point(&excerpt.buffer)
2658                    + Point::new(down_line_count, 0),
2659                Bias::Left,
2660            );
2661            end_point.column = excerpt.buffer.line_len(end_point.row);
2662            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2663            excerpt.max_buffer_row = end_point.row;
2664
2665            excerpt.text_summary = excerpt
2666                .buffer
2667                .text_summary_for_range(excerpt.range.context.clone());
2668
2669            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2670            let old_start_offset = cursor.start().1;
2671            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2672            let edit = Edit {
2673                old: old_start_offset..old_start_offset + old_text_len,
2674                new: new_start_offset..new_start_offset + new_text_len,
2675            };
2676
2677            if let Some(last_edit) = edits.last_mut() {
2678                if last_edit.old.end == edit.old.start {
2679                    last_edit.old.end = edit.old.end;
2680                    last_edit.new.end = edit.new.end;
2681                } else {
2682                    edits.push(edit);
2683                }
2684            } else {
2685                edits.push(edit);
2686            }
2687
2688            new_excerpts.push(excerpt, &());
2689
2690            cursor.next(&());
2691        }
2692
2693        new_excerpts.append(cursor.suffix(&()), &());
2694
2695        drop(cursor);
2696        snapshot.excerpts = new_excerpts;
2697
2698        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2699        cx.emit(Event::Edited {
2700            singleton_buffer_edited: false,
2701            edited_buffer: None,
2702        });
2703        cx.emit(Event::ExcerptsExpanded { ids });
2704        cx.notify();
2705    }
2706
2707    fn sync(&self, cx: &App) {
2708        let changed = self.buffer_changed_since_sync.replace(false);
2709        if !changed {
2710            return;
2711        }
2712
2713        let mut snapshot = self.snapshot.borrow_mut();
2714        let mut excerpts_to_edit = Vec::new();
2715        let mut non_text_state_updated = false;
2716        let mut is_dirty = false;
2717        let mut has_deleted_file = false;
2718        let mut has_conflict = false;
2719        let mut edited = false;
2720        let mut buffers = self.buffers.borrow_mut();
2721        for buffer_state in buffers.values_mut() {
2722            let buffer = buffer_state.buffer.read(cx);
2723            let version = buffer.version();
2724            let non_text_state_update_count = buffer.non_text_state_update_count();
2725
2726            let buffer_edited = version.changed_since(&buffer_state.last_version);
2727            let buffer_non_text_state_updated =
2728                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2729            if buffer_edited || buffer_non_text_state_updated {
2730                buffer_state.last_version = version;
2731                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2732                excerpts_to_edit.extend(
2733                    buffer_state
2734                        .excerpts
2735                        .iter()
2736                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2737                );
2738            }
2739
2740            edited |= buffer_edited;
2741            non_text_state_updated |= buffer_non_text_state_updated;
2742            is_dirty |= buffer.is_dirty();
2743            has_deleted_file |= buffer
2744                .file()
2745                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2746            has_conflict |= buffer.has_conflict();
2747        }
2748        if edited {
2749            snapshot.edit_count += 1;
2750        }
2751        if non_text_state_updated {
2752            snapshot.non_text_state_update_count += 1;
2753        }
2754        snapshot.is_dirty = is_dirty;
2755        snapshot.has_deleted_file = has_deleted_file;
2756        snapshot.has_conflict = has_conflict;
2757
2758        for (id, diff) in self.diffs.iter() {
2759            if snapshot.diffs.get(&id).is_none() {
2760                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2761            }
2762        }
2763
2764        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2765
2766        let mut edits = Vec::new();
2767        let mut new_excerpts = SumTree::default();
2768        let mut cursor = snapshot
2769            .excerpts
2770            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2771
2772        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2773            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2774            let old_excerpt = cursor.item().unwrap();
2775            let buffer = buffer.read(cx);
2776            let buffer_id = buffer.remote_id();
2777
2778            let mut new_excerpt;
2779            if buffer_edited {
2780                edits.extend(
2781                    buffer
2782                        .edits_since_in_range::<usize>(
2783                            old_excerpt.buffer.version(),
2784                            old_excerpt.range.context.clone(),
2785                        )
2786                        .map(|edit| {
2787                            let excerpt_old_start = cursor.start().1;
2788                            let excerpt_new_start =
2789                                ExcerptOffset::new(new_excerpts.summary().text.len);
2790                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2791                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2792                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2793                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2794                            Edit {
2795                                old: old_start..old_end,
2796                                new: new_start..new_end,
2797                            }
2798                        }),
2799                );
2800
2801                new_excerpt = Excerpt::new(
2802                    old_excerpt.id,
2803                    locator.clone(),
2804                    buffer_id,
2805                    buffer.snapshot(),
2806                    old_excerpt.range.clone(),
2807                    old_excerpt.has_trailing_newline,
2808                );
2809            } else {
2810                new_excerpt = old_excerpt.clone();
2811                new_excerpt.buffer = buffer.snapshot();
2812            }
2813
2814            new_excerpts.push(new_excerpt, &());
2815            cursor.next(&());
2816        }
2817        new_excerpts.append(cursor.suffix(&()), &());
2818
2819        drop(cursor);
2820        snapshot.excerpts = new_excerpts;
2821
2822        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2823    }
2824
2825    fn sync_diff_transforms(
2826        &self,
2827        snapshot: &mut MultiBufferSnapshot,
2828        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2829        change_kind: DiffChangeKind,
2830    ) {
2831        if excerpt_edits.is_empty() {
2832            return;
2833        }
2834
2835        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2836        let mut old_diff_transforms = snapshot
2837            .diff_transforms
2838            .cursor::<(ExcerptOffset, usize)>(&());
2839        let mut new_diff_transforms = SumTree::default();
2840        let mut old_expanded_hunks = HashSet::default();
2841        let mut output_edits = Vec::new();
2842        let mut output_delta = 0_isize;
2843        let mut at_transform_boundary = true;
2844        let mut end_of_current_insert = None;
2845
2846        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2847        while let Some(edit) = excerpt_edits.next() {
2848            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2849            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2850                excerpts.prev(&());
2851            }
2852
2853            // Keep any transforms that are before the edit.
2854            if at_transform_boundary {
2855                at_transform_boundary = false;
2856                let transforms_before_edit =
2857                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2858                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2859                if let Some(transform) = old_diff_transforms.item() {
2860                    if old_diff_transforms.end(&()).0 == edit.old.start
2861                        && old_diff_transforms.start().0 < edit.old.start
2862                    {
2863                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2864                        old_diff_transforms.next(&());
2865                    }
2866                }
2867            }
2868
2869            // Compute the start of the edit in output coordinates.
2870            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2871            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2872            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2873
2874            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2875                &edit,
2876                &mut excerpts,
2877                &mut old_diff_transforms,
2878                &mut new_diff_transforms,
2879                &mut end_of_current_insert,
2880                &mut old_expanded_hunks,
2881                &snapshot,
2882                change_kind,
2883            );
2884
2885            // Compute the end of the edit in output coordinates.
2886            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2887            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2888            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2889            let edit_new_end =
2890                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2891            let output_edit = Edit {
2892                old: edit_old_start..edit_old_end,
2893                new: edit_new_start..edit_new_end,
2894            };
2895
2896            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2897            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2898            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2899                output_edits.push(output_edit);
2900            }
2901
2902            // If this is the last edit that intersects the current diff transform,
2903            // then recreate the content up to the end of this transform, to prepare
2904            // for reusing additional slices of the old transforms.
2905            if excerpt_edits.peek().map_or(true, |next_edit| {
2906                next_edit.old.start >= old_diff_transforms.end(&()).0
2907            }) {
2908                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2909                    && match old_diff_transforms.item() {
2910                        Some(DiffTransform::BufferContent {
2911                            inserted_hunk_info: Some(hunk),
2912                            ..
2913                        }) => excerpts.item().is_some_and(|excerpt| {
2914                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2915                        }),
2916                        _ => true,
2917                    };
2918
2919                let mut excerpt_offset = edit.new.end;
2920                if !keep_next_old_transform {
2921                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2922                    old_diff_transforms.next(&());
2923                }
2924
2925                old_expanded_hunks.clear();
2926                self.push_buffer_content_transform(
2927                    &snapshot,
2928                    &mut new_diff_transforms,
2929                    excerpt_offset,
2930                    end_of_current_insert,
2931                );
2932                at_transform_boundary = true;
2933            }
2934        }
2935
2936        // Keep any transforms that are after the last edit.
2937        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2938
2939        // Ensure there's always at least one buffer content transform.
2940        if new_diff_transforms.is_empty() {
2941            new_diff_transforms.push(
2942                DiffTransform::BufferContent {
2943                    summary: Default::default(),
2944                    inserted_hunk_info: None,
2945                },
2946                &(),
2947            );
2948        }
2949
2950        self.subscriptions.publish(output_edits);
2951        drop(old_diff_transforms);
2952        drop(excerpts);
2953        snapshot.diff_transforms = new_diff_transforms;
2954        snapshot.edit_count += 1;
2955
2956        #[cfg(any(test, feature = "test-support"))]
2957        snapshot.check_invariants();
2958    }
2959
2960    #[allow(clippy::too_many_arguments)]
2961    fn recompute_diff_transforms_for_edit(
2962        &self,
2963        edit: &Edit<TypedOffset<Excerpt>>,
2964        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2965        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2966        new_diff_transforms: &mut SumTree<DiffTransform>,
2967        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2968        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2969        snapshot: &MultiBufferSnapshot,
2970        change_kind: DiffChangeKind,
2971    ) -> bool {
2972        log::trace!(
2973            "recomputing diff transform for edit {:?} => {:?}",
2974            edit.old.start.value..edit.old.end.value,
2975            edit.new.start.value..edit.new.end.value
2976        );
2977
2978        // Record which hunks were previously expanded.
2979        while let Some(item) = old_diff_transforms.item() {
2980            if let Some(hunk_info) = item.hunk_info() {
2981                log::trace!(
2982                    "previously expanded hunk at {}",
2983                    old_diff_transforms.start().0
2984                );
2985                old_expanded_hunks.insert(hunk_info);
2986            }
2987            if old_diff_transforms.end(&()).0 > edit.old.end {
2988                break;
2989            }
2990            old_diff_transforms.next(&());
2991        }
2992
2993        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2994        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2995        if old_expanded_hunks.is_empty()
2996            && change_kind == DiffChangeKind::BufferEdited
2997            && !all_diff_hunks_expanded
2998        {
2999            return false;
3000        }
3001
3002        // Visit each excerpt that intersects the edit.
3003        let mut did_expand_hunks = false;
3004        while let Some(excerpt) = excerpts.item() {
3005            // Recompute the expanded hunks in the portion of the excerpt that
3006            // intersects the edit.
3007            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3008                let buffer = &excerpt.buffer;
3009                let excerpt_start = *excerpts.start();
3010                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3011                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3012                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3013                let edit_buffer_start =
3014                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3015                let edit_buffer_end =
3016                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3017                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3018                let edit_anchor_range =
3019                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3020
3021                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3022                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3023                        continue;
3024                    }
3025
3026                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3027                    if hunk_buffer_range.start < excerpt_buffer_start {
3028                        log::trace!("skipping hunk that starts before excerpt");
3029                        continue;
3030                    }
3031
3032                    let hunk_info = DiffTransformHunkInfo {
3033                        excerpt_id: excerpt.id,
3034                        hunk_start_anchor: hunk.buffer_range.start,
3035                        hunk_secondary_status: hunk.secondary_status,
3036                    };
3037
3038                    let hunk_excerpt_start = excerpt_start
3039                        + ExcerptOffset::new(
3040                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3041                        );
3042                    let hunk_excerpt_end = excerpt_end.min(
3043                        excerpt_start
3044                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3045                    );
3046
3047                    self.push_buffer_content_transform(
3048                        snapshot,
3049                        new_diff_transforms,
3050                        hunk_excerpt_start,
3051                        *end_of_current_insert,
3052                    );
3053
3054                    // For every existing hunk, determine if it was previously expanded
3055                    // and if it should currently be expanded.
3056                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3057                    let should_expand_hunk = match &change_kind {
3058                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3059                            was_previously_expanded || all_diff_hunks_expanded
3060                        }
3061                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3062                            let intersects = hunk_buffer_range.is_empty()
3063                                || hunk_buffer_range.end > edit_buffer_start;
3064                            if *expand {
3065                                intersects || was_previously_expanded || all_diff_hunks_expanded
3066                            } else {
3067                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3068                            }
3069                        }
3070                        _ => was_previously_expanded || all_diff_hunks_expanded,
3071                    };
3072
3073                    if should_expand_hunk {
3074                        did_expand_hunks = true;
3075                        log::trace!(
3076                            "expanding hunk {:?}, excerpt:{:?}",
3077                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3078                            excerpt.id
3079                        );
3080
3081                        if !hunk.diff_base_byte_range.is_empty()
3082                            && hunk_buffer_range.start >= edit_buffer_start
3083                            && hunk_buffer_range.start <= excerpt_buffer_end
3084                        {
3085                            let base_text = diff.base_text();
3086                            let mut text_cursor =
3087                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3088                            let mut base_text_summary =
3089                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3090
3091                            let mut has_trailing_newline = false;
3092                            if base_text_summary.last_line_chars > 0 {
3093                                base_text_summary += TextSummary::newline();
3094                                has_trailing_newline = true;
3095                            }
3096
3097                            new_diff_transforms.push(
3098                                DiffTransform::DeletedHunk {
3099                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3100                                    summary: base_text_summary,
3101                                    buffer_id: excerpt.buffer_id,
3102                                    hunk_info,
3103                                    has_trailing_newline,
3104                                },
3105                                &(),
3106                            );
3107                        }
3108
3109                        if !hunk_buffer_range.is_empty() {
3110                            *end_of_current_insert =
3111                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3112                        }
3113                    }
3114                }
3115            }
3116
3117            if excerpts.end(&()) <= edit.new.end {
3118                excerpts.next(&());
3119            } else {
3120                break;
3121            }
3122        }
3123
3124        did_expand_hunks || !old_expanded_hunks.is_empty()
3125    }
3126
3127    fn append_diff_transforms(
3128        &self,
3129        new_transforms: &mut SumTree<DiffTransform>,
3130        subtree: SumTree<DiffTransform>,
3131    ) {
3132        if let Some(DiffTransform::BufferContent {
3133            inserted_hunk_info,
3134            summary,
3135        }) = subtree.first()
3136        {
3137            if self.extend_last_buffer_content_transform(
3138                new_transforms,
3139                *inserted_hunk_info,
3140                *summary,
3141            ) {
3142                let mut cursor = subtree.cursor::<()>(&());
3143                cursor.next(&());
3144                cursor.next(&());
3145                new_transforms.append(cursor.suffix(&()), &());
3146                return;
3147            }
3148        }
3149        new_transforms.append(subtree, &());
3150    }
3151
3152    fn push_diff_transform(
3153        &self,
3154        new_transforms: &mut SumTree<DiffTransform>,
3155        transform: DiffTransform,
3156    ) {
3157        if let DiffTransform::BufferContent {
3158            inserted_hunk_info: inserted_hunk_anchor,
3159            summary,
3160        } = transform
3161        {
3162            if self.extend_last_buffer_content_transform(
3163                new_transforms,
3164                inserted_hunk_anchor,
3165                summary,
3166            ) {
3167                return;
3168            }
3169        }
3170        new_transforms.push(transform, &());
3171    }
3172
3173    fn push_buffer_content_transform(
3174        &self,
3175        old_snapshot: &MultiBufferSnapshot,
3176        new_transforms: &mut SumTree<DiffTransform>,
3177        end_offset: ExcerptOffset,
3178        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3179    ) {
3180        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3181            (end_offset.min(insertion_end_offset), Some(hunk_info))
3182        });
3183        let unchanged_region = [(end_offset, None)];
3184
3185        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3186        {
3187            let start_offset = new_transforms.summary().excerpt_len();
3188            if end_offset <= start_offset {
3189                continue;
3190            }
3191            let summary_to_add = old_snapshot
3192                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3193
3194            if !self.extend_last_buffer_content_transform(
3195                new_transforms,
3196                inserted_hunk_info,
3197                summary_to_add,
3198            ) {
3199                new_transforms.push(
3200                    DiffTransform::BufferContent {
3201                        summary: summary_to_add,
3202                        inserted_hunk_info,
3203                    },
3204                    &(),
3205                )
3206            }
3207        }
3208    }
3209
3210    fn extend_last_buffer_content_transform(
3211        &self,
3212        new_transforms: &mut SumTree<DiffTransform>,
3213        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3214        summary_to_add: TextSummary,
3215    ) -> bool {
3216        let mut did_extend = false;
3217        new_transforms.update_last(
3218            |last_transform| {
3219                if let DiffTransform::BufferContent {
3220                    summary,
3221                    inserted_hunk_info: inserted_hunk_anchor,
3222                } = last_transform
3223                {
3224                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3225                        *summary += summary_to_add;
3226                        did_extend = true;
3227                    }
3228                }
3229            },
3230            &(),
3231        );
3232        did_extend
3233    }
3234}
3235
3236#[cfg(any(test, feature = "test-support"))]
3237impl MultiBuffer {
3238    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3239        let buffer = cx.new(|cx| Buffer::local(text, cx));
3240        cx.new(|cx| Self::singleton(buffer, cx))
3241    }
3242
3243    pub fn build_multi<const COUNT: usize>(
3244        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3245        cx: &mut gpui::App,
3246    ) -> Entity<Self> {
3247        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3248        for (text, ranges) in excerpts {
3249            let buffer = cx.new(|cx| Buffer::local(text, cx));
3250            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3251                context: range,
3252                primary: None,
3253            });
3254            multi.update(cx, |multi, cx| {
3255                multi.push_excerpts(buffer, excerpt_ranges, cx)
3256            });
3257        }
3258
3259        multi
3260    }
3261
3262    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3263        cx.new(|cx| Self::singleton(buffer, cx))
3264    }
3265
3266    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3267        cx.new(|cx| {
3268            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3269            let mutation_count = rng.gen_range(1..=5);
3270            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3271            multibuffer
3272        })
3273    }
3274
3275    pub fn randomly_edit(
3276        &mut self,
3277        rng: &mut impl rand::Rng,
3278        edit_count: usize,
3279        cx: &mut Context<Self>,
3280    ) {
3281        use util::RandomCharIter;
3282
3283        let snapshot = self.read(cx);
3284        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3285        let mut last_end = None;
3286        for _ in 0..edit_count {
3287            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3288                break;
3289            }
3290
3291            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3292            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3293            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3294            last_end = Some(end);
3295
3296            let mut range = start..end;
3297            if rng.gen_bool(0.2) {
3298                mem::swap(&mut range.start, &mut range.end);
3299            }
3300
3301            let new_text_len = rng.gen_range(0..10);
3302            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3303
3304            edits.push((range, new_text.into()));
3305        }
3306        log::info!("mutating multi-buffer with {:?}", edits);
3307        drop(snapshot);
3308
3309        self.edit(edits, None, cx);
3310    }
3311
3312    pub fn randomly_edit_excerpts(
3313        &mut self,
3314        rng: &mut impl rand::Rng,
3315        mutation_count: usize,
3316        cx: &mut Context<Self>,
3317    ) {
3318        use rand::prelude::*;
3319        use std::env;
3320        use util::RandomCharIter;
3321
3322        let max_excerpts = env::var("MAX_EXCERPTS")
3323            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3324            .unwrap_or(5);
3325
3326        let mut buffers = Vec::new();
3327        for _ in 0..mutation_count {
3328            if rng.gen_bool(0.05) {
3329                log::info!("Clearing multi-buffer");
3330                self.clear(cx);
3331                continue;
3332            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3333                let ids = self.excerpt_ids();
3334                let mut excerpts = HashSet::default();
3335                for _ in 0..rng.gen_range(0..ids.len()) {
3336                    excerpts.extend(ids.choose(rng).copied());
3337                }
3338
3339                let line_count = rng.gen_range(0..5);
3340
3341                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3342
3343                self.expand_excerpts(
3344                    excerpts.iter().cloned(),
3345                    line_count,
3346                    ExpandExcerptDirection::UpAndDown,
3347                    cx,
3348                );
3349                continue;
3350            }
3351
3352            let excerpt_ids = self.excerpt_ids();
3353            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3354                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3355                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3356                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3357                    let buffer = buffers.last().unwrap().read(cx);
3358                    log::info!(
3359                        "Creating new buffer {} with text: {:?}",
3360                        buffer.remote_id(),
3361                        buffer.text()
3362                    );
3363                    buffers.last().unwrap().clone()
3364                } else {
3365                    self.buffers
3366                        .borrow()
3367                        .values()
3368                        .choose(rng)
3369                        .unwrap()
3370                        .buffer
3371                        .clone()
3372                };
3373
3374                let buffer = buffer_handle.read(cx);
3375                let buffer_text = buffer.text();
3376                let ranges = (0..rng.gen_range(0..5))
3377                    .map(|_| {
3378                        let end_ix =
3379                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3380                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3381                        ExcerptRange {
3382                            context: start_ix..end_ix,
3383                            primary: None,
3384                        }
3385                    })
3386                    .collect::<Vec<_>>();
3387                log::info!(
3388                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3389                    buffer_handle.read(cx).remote_id(),
3390                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3391                    ranges
3392                        .iter()
3393                        .map(|r| &buffer_text[r.context.clone()])
3394                        .collect::<Vec<_>>()
3395                );
3396
3397                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3398                log::info!("Inserted with ids: {:?}", excerpt_id);
3399            } else {
3400                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3401                let mut excerpts_to_remove = excerpt_ids
3402                    .choose_multiple(rng, remove_count)
3403                    .cloned()
3404                    .collect::<Vec<_>>();
3405                let snapshot = self.snapshot.borrow();
3406                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3407                drop(snapshot);
3408                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3409                self.remove_excerpts(excerpts_to_remove, cx);
3410            }
3411        }
3412    }
3413
3414    pub fn randomly_mutate(
3415        &mut self,
3416        rng: &mut impl rand::Rng,
3417        mutation_count: usize,
3418        cx: &mut Context<Self>,
3419    ) {
3420        use rand::prelude::*;
3421
3422        if rng.gen_bool(0.7) || self.singleton {
3423            let buffer = self
3424                .buffers
3425                .borrow()
3426                .values()
3427                .choose(rng)
3428                .map(|state| state.buffer.clone());
3429
3430            if let Some(buffer) = buffer {
3431                buffer.update(cx, |buffer, cx| {
3432                    if rng.gen() {
3433                        buffer.randomly_edit(rng, mutation_count, cx);
3434                    } else {
3435                        buffer.randomly_undo_redo(rng, cx);
3436                    }
3437                });
3438            } else {
3439                self.randomly_edit(rng, mutation_count, cx);
3440            }
3441        } else {
3442            self.randomly_edit_excerpts(rng, mutation_count, cx);
3443        }
3444
3445        self.check_invariants(cx);
3446    }
3447
3448    fn check_invariants(&self, cx: &App) {
3449        self.read(cx).check_invariants();
3450    }
3451}
3452
3453impl EventEmitter<Event> for MultiBuffer {}
3454
3455impl MultiBufferSnapshot {
3456    pub fn text(&self) -> String {
3457        self.chunks(0..self.len(), false)
3458            .map(|chunk| chunk.text)
3459            .collect()
3460    }
3461
3462    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3463        self.reversed_chunks_in_range(0..position.to_offset(self))
3464            .flat_map(|c| c.chars().rev())
3465    }
3466
3467    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3468        let mut cursor = self.cursor::<usize>();
3469        cursor.seek(&range.end);
3470        let current_chunks = cursor.region().as_ref().map(|region| {
3471            let start_overshoot = range.start.saturating_sub(region.range.start);
3472            let end_overshoot = range.end - region.range.start;
3473            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3474            let start = region.buffer_range.start + start_overshoot;
3475            region.buffer.reversed_chunks_in_range(start..end)
3476        });
3477        ReversedMultiBufferChunks {
3478            cursor,
3479            current_chunks,
3480            start: range.start,
3481            offset: range.end,
3482        }
3483    }
3484
3485    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3486        let offset = position.to_offset(self);
3487        self.text_for_range(offset..self.len())
3488            .flat_map(|chunk| chunk.chars())
3489    }
3490
3491    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3492        self.chunks(range, false).map(|chunk| chunk.text)
3493    }
3494
3495    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3496        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3497            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3498    }
3499
3500    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3501    where
3502        T: ToOffset,
3503    {
3504        let position = position.to_offset(self);
3505        position == self.clip_offset(position, Bias::Left)
3506            && self
3507                .bytes_in_range(position..self.len())
3508                .flatten()
3509                .copied()
3510                .take(needle.len())
3511                .eq(needle.bytes())
3512    }
3513
3514    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3515        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3516    }
3517
3518    pub fn diff_hunks_in_range<T: ToPoint>(
3519        &self,
3520        range: Range<T>,
3521    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3522        let query_range = range.start.to_point(self)..range.end.to_point(self);
3523        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3524            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3525                log::debug!("no diff found for {:?}", buffer.remote_id());
3526                return None;
3527            };
3528            let buffer_start = buffer.anchor_before(buffer_range.start);
3529            let buffer_end = buffer.anchor_after(buffer_range.end);
3530            Some(
3531                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3532                    .filter_map(|hunk| {
3533                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3534                            return None;
3535                        }
3536                        Some((hunk.range.clone(), hunk))
3537                    }),
3538            )
3539        })
3540        .filter_map(move |(range, hunk, excerpt)| {
3541            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3542            {
3543                return None;
3544            }
3545            let end_row = if range.end.column == 0 {
3546                range.end.row
3547            } else {
3548                range.end.row + 1
3549            };
3550            Some(MultiBufferDiffHunk {
3551                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3552                buffer_id: excerpt.buffer_id,
3553                excerpt_id: excerpt.id,
3554                buffer_range: hunk.buffer_range.clone(),
3555                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3556                secondary_status: hunk.secondary_status,
3557            })
3558        })
3559    }
3560
3561    pub fn excerpt_ids_for_range<T: ToOffset>(
3562        &self,
3563        range: Range<T>,
3564    ) -> impl Iterator<Item = ExcerptId> + '_ {
3565        let range = range.start.to_offset(self)..range.end.to_offset(self);
3566        let mut cursor = self.cursor::<usize>();
3567        cursor.seek(&range.start);
3568        std::iter::from_fn(move || {
3569            let region = cursor.region()?;
3570            if region.range.start >= range.end {
3571                return None;
3572            }
3573            cursor.next_excerpt();
3574            Some(region.excerpt.id)
3575        })
3576    }
3577
3578    pub fn buffer_ids_for_range<T: ToOffset>(
3579        &self,
3580        range: Range<T>,
3581    ) -> impl Iterator<Item = BufferId> + '_ {
3582        let range = range.start.to_offset(self)..range.end.to_offset(self);
3583        let mut cursor = self.cursor::<usize>();
3584        cursor.seek(&range.start);
3585        std::iter::from_fn(move || {
3586            let region = cursor.region()?;
3587            if region.range.start > range.end
3588                || region.range.start == range.end && region.range.start > range.start
3589            {
3590                return None;
3591            }
3592            cursor.next_excerpt();
3593            Some(region.excerpt.buffer_id)
3594        })
3595    }
3596
3597    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3598        &self,
3599        ranges: impl Iterator<Item = Range<T>>,
3600    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3601        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3602    }
3603
3604    pub fn range_to_buffer_ranges<T: ToOffset>(
3605        &self,
3606        range: Range<T>,
3607    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3608        let start = range.start.to_offset(&self);
3609        let end = range.end.to_offset(&self);
3610
3611        let mut cursor = self.cursor::<usize>();
3612        cursor.seek(&start);
3613
3614        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3615        while let Some(region) = cursor.region() {
3616            if region.range.start > end {
3617                break;
3618            }
3619            if region.is_main_buffer {
3620                let start_overshoot = start.saturating_sub(region.range.start);
3621                let end_overshoot = end.saturating_sub(region.range.start);
3622                let start = region
3623                    .buffer_range
3624                    .end
3625                    .min(region.buffer_range.start + start_overshoot);
3626                let end = region
3627                    .buffer_range
3628                    .end
3629                    .min(region.buffer_range.start + end_overshoot);
3630                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3631                    *excerpt_id == region.excerpt.id && prev_range.end == start
3632                }) {
3633                    prev.1.end = end;
3634                } else {
3635                    result.push((region.buffer, start..end, region.excerpt.id));
3636                }
3637            }
3638            cursor.next();
3639        }
3640        result
3641    }
3642
3643    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3644        &self,
3645        range: Range<T>,
3646    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3647        let start = range.start.to_offset(&self);
3648        let end = range.end.to_offset(&self);
3649
3650        let mut cursor = self.cursor::<usize>();
3651        cursor.seek(&start);
3652
3653        std::iter::from_fn(move || {
3654            let region = cursor.region()?;
3655            if region.range.start > end {
3656                return None;
3657            }
3658            let start_overshoot = start.saturating_sub(region.range.start);
3659            let end_overshoot = end.saturating_sub(region.range.start);
3660            let start = region
3661                .buffer_range
3662                .end
3663                .min(region.buffer_range.start + start_overshoot);
3664            let end = region
3665                .buffer_range
3666                .end
3667                .min(region.buffer_range.start + end_overshoot);
3668
3669            let region_excerpt_id = region.excerpt.id;
3670            let deleted_hunk_anchor = if region.is_main_buffer {
3671                None
3672            } else {
3673                Some(self.anchor_before(region.range.start))
3674            };
3675            let result = (
3676                region.buffer,
3677                start..end,
3678                region_excerpt_id,
3679                deleted_hunk_anchor,
3680            );
3681            cursor.next();
3682            Some(result)
3683        })
3684    }
3685
3686    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3687    /// coordinates.
3688    ///
3689    /// The given callback will be called for every excerpt intersecting the given range. It will
3690    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3691    /// The callback should return an iterator of metadata items from that buffer, each paired
3692    /// with a buffer range.
3693    ///
3694    /// The returned iterator yields each of these metadata items, paired with its range in
3695    /// multi-buffer coordinates.
3696    fn lift_buffer_metadata<'a, D, M, I>(
3697        &'a self,
3698        query_range: Range<D>,
3699        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3700    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3701    where
3702        I: Iterator<Item = (Range<D>, M)> + 'a,
3703        D: TextDimension + Ord + Sub<D, Output = D>,
3704    {
3705        let max_position = D::from_text_summary(&self.text_summary());
3706        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3707        let mut cursor = self.cursor::<D>();
3708
3709        // Find the excerpt and buffer offset where the given range ends.
3710        cursor.seek(&query_range.end);
3711        let mut range_end = None;
3712        while let Some(region) = cursor.region() {
3713            if region.is_main_buffer {
3714                let mut buffer_end = region.buffer_range.start;
3715                let overshoot = if query_range.end > region.range.start {
3716                    query_range.end - region.range.start
3717                } else {
3718                    D::default()
3719                };
3720                buffer_end.add_assign(&overshoot);
3721                range_end = Some((region.excerpt.id, buffer_end));
3722                break;
3723            }
3724            cursor.next();
3725        }
3726
3727        cursor.seek(&query_range.start);
3728
3729        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3730            if region.range.start > D::zero(&()) {
3731                cursor.prev()
3732            }
3733        }
3734
3735        iter::from_fn(move || loop {
3736            let excerpt = cursor.excerpt()?;
3737
3738            // If we have already retrieved metadata for this excerpt, continue to use it.
3739            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3740                .as_mut()
3741                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3742            {
3743                Some(metadata)
3744            }
3745            // Otherwise, compute the intersection of the input range with the excerpt's range,
3746            // and retrieve the metadata for the resulting range.
3747            else {
3748                let region = cursor.region()?;
3749                let mut buffer_start;
3750                if region.is_main_buffer {
3751                    buffer_start = region.buffer_range.start;
3752                    if query_range.start > region.range.start {
3753                        let overshoot = query_range.start - region.range.start;
3754                        buffer_start.add_assign(&overshoot);
3755                    }
3756                    buffer_start = buffer_start.min(region.buffer_range.end);
3757                } else {
3758                    buffer_start = cursor.main_buffer_position()?;
3759                };
3760                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3761                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3762                    if excerpt.id == end_excerpt_id {
3763                        buffer_end = buffer_end.min(end_buffer_offset);
3764                    }
3765                }
3766
3767                if let Some(iterator) =
3768                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3769                {
3770                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3771                } else {
3772                    None
3773                }
3774            };
3775
3776            // Visit each metadata item.
3777            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3778            {
3779                // Find the multibuffer regions that contain the start and end of
3780                // the metadata item's range.
3781                if metadata_buffer_range.start > D::default() {
3782                    while let Some(region) = cursor.region() {
3783                        if region.is_main_buffer
3784                            && (region.buffer_range.end >= metadata_buffer_range.start
3785                                || cursor.is_at_end_of_excerpt())
3786                        {
3787                            break;
3788                        }
3789                        cursor.next();
3790                    }
3791                }
3792                let start_region = cursor.region()?;
3793                while let Some(region) = cursor.region() {
3794                    if region.is_main_buffer
3795                        && (region.buffer_range.end > metadata_buffer_range.end
3796                            || cursor.is_at_end_of_excerpt())
3797                    {
3798                        break;
3799                    }
3800                    cursor.next();
3801                }
3802                let end_region = cursor.region();
3803
3804                // Convert the metadata item's range into multibuffer coordinates.
3805                let mut start_position = start_region.range.start;
3806                let region_buffer_start = start_region.buffer_range.start;
3807                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3808                {
3809                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3810                    start_position = start_position.min(start_region.range.end);
3811                }
3812
3813                let mut end_position = max_position;
3814                if let Some(end_region) = &end_region {
3815                    end_position = end_region.range.start;
3816                    debug_assert!(end_region.is_main_buffer);
3817                    let region_buffer_start = end_region.buffer_range.start;
3818                    if metadata_buffer_range.end > region_buffer_start {
3819                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3820                    }
3821                    end_position = end_position.min(end_region.range.end);
3822                }
3823
3824                if start_position <= query_range.end && end_position >= query_range.start {
3825                    return Some((start_position..end_position, metadata, excerpt));
3826                }
3827            }
3828            // When there are no more metadata items for this excerpt, move to the next excerpt.
3829            else {
3830                current_excerpt_metadata.take();
3831                if let Some((end_excerpt_id, _)) = range_end {
3832                    if excerpt.id == end_excerpt_id {
3833                        return None;
3834                    }
3835                }
3836                cursor.next_excerpt();
3837            }
3838        })
3839    }
3840
3841    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3842        let offset = position.to_offset(self);
3843
3844        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3845        cursor.seek(&DimensionPair {
3846            key: offset,
3847            value: None,
3848        });
3849        cursor.seek_to_start_of_current_excerpt();
3850        let excerpt = cursor.excerpt()?;
3851
3852        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3853        let current_position = self
3854            .anchor_before(offset)
3855            .text_anchor
3856            .to_offset(&excerpt.buffer);
3857        let excerpt_end = excerpt
3858            .buffer
3859            .anchor_before(excerpt_end.min(current_position));
3860
3861        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3862            for hunk in diff.hunks_intersecting_range_rev(
3863                excerpt.range.context.start..excerpt_end,
3864                &excerpt.buffer,
3865            ) {
3866                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3867                if hunk_end >= current_position {
3868                    continue;
3869                }
3870                let start =
3871                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3872                        .to_point(&self);
3873                return Some(MultiBufferRow(start.row));
3874            }
3875        }
3876
3877        loop {
3878            cursor.prev_excerpt();
3879            let excerpt = cursor.excerpt()?;
3880
3881            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3882                continue;
3883            };
3884            let mut hunks =
3885                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3886            let Some(hunk) = hunks.next() else {
3887                continue;
3888            };
3889            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3890                .to_point(&self);
3891            return Some(MultiBufferRow(start.row));
3892        }
3893    }
3894
3895    pub fn has_diff_hunks(&self) -> bool {
3896        self.diffs.values().any(|diff| !diff.is_empty())
3897    }
3898
3899    pub fn surrounding_word<T: ToOffset>(
3900        &self,
3901        start: T,
3902        for_completion: bool,
3903    ) -> (Range<usize>, Option<CharKind>) {
3904        let mut start = start.to_offset(self);
3905        let mut end = start;
3906        let mut next_chars = self.chars_at(start).peekable();
3907        let mut prev_chars = self.reversed_chars_at(start).peekable();
3908
3909        let classifier = self
3910            .char_classifier_at(start)
3911            .for_completion(for_completion);
3912
3913        let word_kind = cmp::max(
3914            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3915            next_chars.peek().copied().map(|c| classifier.kind(c)),
3916        );
3917
3918        for ch in prev_chars {
3919            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3920                start -= ch.len_utf8();
3921            } else {
3922                break;
3923            }
3924        }
3925
3926        for ch in next_chars {
3927            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3928                end += ch.len_utf8();
3929            } else {
3930                break;
3931            }
3932        }
3933
3934        (start..end, word_kind)
3935    }
3936
3937    pub fn is_singleton(&self) -> bool {
3938        self.singleton
3939    }
3940
3941    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3942        if self.singleton {
3943            self.excerpts
3944                .iter()
3945                .next()
3946                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3947        } else {
3948            None
3949        }
3950    }
3951
3952    pub fn len(&self) -> usize {
3953        self.diff_transforms.summary().output.len
3954    }
3955
3956    pub fn is_empty(&self) -> bool {
3957        self.excerpts.summary().text.len == 0
3958    }
3959
3960    pub fn widest_line_number(&self) -> u32 {
3961        self.excerpts.summary().widest_line_number + 1
3962    }
3963
3964    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3965        let range = range.start.to_offset(self)..range.end.to_offset(self);
3966        let mut excerpts = self.cursor::<usize>();
3967        excerpts.seek(&range.start);
3968
3969        let mut chunk;
3970        let mut has_trailing_newline;
3971        let excerpt_bytes;
3972        if let Some(region) = excerpts.region() {
3973            let mut bytes = region.buffer.bytes_in_range(
3974                region.buffer_range.start + range.start - region.range.start
3975                    ..(region.buffer_range.start + range.end - region.range.start)
3976                        .min(region.buffer_range.end),
3977            );
3978            chunk = bytes.next().unwrap_or(&[][..]);
3979            excerpt_bytes = Some(bytes);
3980            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3981            if chunk.is_empty() && has_trailing_newline {
3982                chunk = b"\n";
3983                has_trailing_newline = false;
3984            }
3985        } else {
3986            chunk = &[][..];
3987            excerpt_bytes = None;
3988            has_trailing_newline = false;
3989        };
3990
3991        MultiBufferBytes {
3992            range,
3993            cursor: excerpts,
3994            excerpt_bytes,
3995            has_trailing_newline,
3996            chunk,
3997        }
3998    }
3999
4000    pub fn reversed_bytes_in_range<T: ToOffset>(
4001        &self,
4002        range: Range<T>,
4003    ) -> ReversedMultiBufferBytes {
4004        let range = range.start.to_offset(self)..range.end.to_offset(self);
4005        let mut chunks = self.reversed_chunks_in_range(range.clone());
4006        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4007        ReversedMultiBufferBytes {
4008            range,
4009            chunks,
4010            chunk,
4011        }
4012    }
4013
4014    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4015        let mut cursor = self.cursor::<Point>();
4016        cursor.seek(&Point::new(start_row.0, 0));
4017        let mut result = MultiBufferRows {
4018            point: Point::new(0, 0),
4019            is_empty: self.excerpts.is_empty(),
4020            cursor,
4021        };
4022        result.seek(start_row);
4023        result
4024    }
4025
4026    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4027        let mut chunks = MultiBufferChunks {
4028            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4029            range: 0..0,
4030            excerpts: self.excerpts.cursor(&()),
4031            diff_transforms: self.diff_transforms.cursor(&()),
4032            diffs: &self.diffs,
4033            diff_base_chunks: None,
4034            excerpt_chunks: None,
4035            buffer_chunk: None,
4036            language_aware,
4037        };
4038        let range = range.start.to_offset(self)..range.end.to_offset(self);
4039        chunks.seek(range);
4040        chunks
4041    }
4042
4043    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4044        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4045    }
4046
4047    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4048        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4049    }
4050
4051    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4052        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4053    }
4054
4055    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4056        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4057            buffer.clip_point_utf16(Unclipped(point), bias)
4058        })
4059    }
4060
4061    pub fn offset_to_point(&self, offset: usize) -> Point {
4062        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4063    }
4064
4065    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4066        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4067    }
4068
4069    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4070        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4071    }
4072
4073    pub fn point_to_offset(&self, point: Point) -> usize {
4074        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4075    }
4076
4077    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4078        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4079    }
4080
4081    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4082        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4083    }
4084
4085    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4086        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4087    }
4088
4089    fn clip_dimension<D>(
4090        &self,
4091        position: D,
4092        bias: Bias,
4093        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4094    ) -> D
4095    where
4096        D: TextDimension + Ord + Sub<D, Output = D>,
4097    {
4098        let mut cursor = self.cursor();
4099        cursor.seek(&position);
4100        if let Some(region) = cursor.region() {
4101            if position >= region.range.end {
4102                return region.range.end;
4103            }
4104            let overshoot = position - region.range.start;
4105            let mut buffer_position = region.buffer_range.start;
4106            buffer_position.add_assign(&overshoot);
4107            let clipped_buffer_position =
4108                clip_buffer_position(&region.buffer, buffer_position, bias);
4109            let mut position = region.range.start;
4110            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4111            position
4112        } else {
4113            D::from_text_summary(&self.text_summary())
4114        }
4115    }
4116
4117    fn convert_dimension<D1, D2>(
4118        &self,
4119        key: D1,
4120        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4121    ) -> D2
4122    where
4123        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4124        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4125    {
4126        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4127        cursor.seek(&DimensionPair { key, value: None });
4128        if let Some(region) = cursor.region() {
4129            if key >= region.range.end.key {
4130                return region.range.end.value.unwrap();
4131            }
4132            let start_key = region.range.start.key;
4133            let start_value = region.range.start.value.unwrap();
4134            let buffer_start_key = region.buffer_range.start.key;
4135            let buffer_start_value = region.buffer_range.start.value.unwrap();
4136            let mut buffer_key = buffer_start_key;
4137            buffer_key.add_assign(&(key - start_key));
4138            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4139            let mut result = start_value;
4140            result.add_assign(&(buffer_value - buffer_start_value));
4141            result
4142        } else {
4143            D2::from_text_summary(&self.text_summary())
4144        }
4145    }
4146
4147    pub fn point_to_buffer_offset<T: ToOffset>(
4148        &self,
4149        point: T,
4150    ) -> Option<(&BufferSnapshot, usize)> {
4151        let offset = point.to_offset(self);
4152        let mut cursor = self.cursor::<usize>();
4153        cursor.seek(&offset);
4154        let region = cursor.region()?;
4155        let overshoot = offset - region.range.start;
4156        let buffer_offset = region.buffer_range.start + overshoot;
4157        Some((region.buffer, buffer_offset))
4158    }
4159
4160    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4161        let mut cursor = self.cursor::<Point>();
4162        cursor.seek(&point);
4163        let region = cursor.region()?;
4164        let overshoot = point - region.range.start;
4165        let buffer_offset = region.buffer_range.start + overshoot;
4166        Some((region.buffer, buffer_offset, region.is_main_buffer))
4167    }
4168
4169    pub fn suggested_indents(
4170        &self,
4171        rows: impl IntoIterator<Item = u32>,
4172        cx: &App,
4173    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4174        let mut result = BTreeMap::new();
4175
4176        let mut rows_for_excerpt = Vec::new();
4177        let mut cursor = self.cursor::<Point>();
4178        let mut rows = rows.into_iter().peekable();
4179        let mut prev_row = u32::MAX;
4180        let mut prev_language_indent_size = IndentSize::default();
4181
4182        while let Some(row) = rows.next() {
4183            cursor.seek(&Point::new(row, 0));
4184            let Some(region) = cursor.region() else {
4185                continue;
4186            };
4187
4188            // Retrieve the language and indent size once for each disjoint region being indented.
4189            let single_indent_size = if row.saturating_sub(1) == prev_row {
4190                prev_language_indent_size
4191            } else {
4192                region
4193                    .buffer
4194                    .language_indent_size_at(Point::new(row, 0), cx)
4195            };
4196            prev_language_indent_size = single_indent_size;
4197            prev_row = row;
4198
4199            let start_buffer_row = region.buffer_range.start.row;
4200            let start_multibuffer_row = region.range.start.row;
4201            let end_multibuffer_row = region.range.end.row;
4202
4203            rows_for_excerpt.push(row);
4204            while let Some(next_row) = rows.peek().copied() {
4205                if end_multibuffer_row > next_row {
4206                    rows_for_excerpt.push(next_row);
4207                    rows.next();
4208                } else {
4209                    break;
4210                }
4211            }
4212
4213            let buffer_rows = rows_for_excerpt
4214                .drain(..)
4215                .map(|row| start_buffer_row + row - start_multibuffer_row);
4216            let buffer_indents = region
4217                .buffer
4218                .suggested_indents(buffer_rows, single_indent_size);
4219            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4220                (
4221                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4222                    indent,
4223                )
4224            });
4225            result.extend(multibuffer_indents);
4226        }
4227
4228        result
4229    }
4230
4231    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4232        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4233            let mut size = buffer.indent_size_for_line(range.start.row);
4234            size.len = size
4235                .len
4236                .min(range.end.column)
4237                .saturating_sub(range.start.column);
4238            size
4239        } else {
4240            IndentSize::spaces(0)
4241        }
4242    }
4243
4244    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4245        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4246            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4247        } else {
4248            LineIndent::spaces(0)
4249        }
4250    }
4251
4252    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4253        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4254
4255        if self.settings_at(0, cx).extend_comment_on_newline {
4256            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4257                let delimiters = language_scope.line_comment_prefixes();
4258                for delimiter in delimiters {
4259                    if *self
4260                        .chars_at(Point::new(row.0, indent.len() as u32))
4261                        .take(delimiter.chars().count())
4262                        .collect::<String>()
4263                        .as_str()
4264                        == **delimiter
4265                    {
4266                        indent.push_str(&delimiter);
4267                        break;
4268                    }
4269                }
4270            }
4271        }
4272
4273        indent
4274    }
4275
4276    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4277    where
4278        T: ToOffset,
4279    {
4280        for char in self.reversed_chars_at(position) {
4281            if !char.is_whitespace() {
4282                return false;
4283            }
4284            if char == '\n' {
4285                return true;
4286            }
4287        }
4288        return true;
4289    }
4290
4291    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4292        while row.0 > 0 {
4293            row.0 -= 1;
4294            if !self.is_line_blank(row) {
4295                return Some(row);
4296            }
4297        }
4298        None
4299    }
4300
4301    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4302        if let Some((_, range)) = self.buffer_line_for_row(row) {
4303            range.end.column - range.start.column
4304        } else {
4305            0
4306        }
4307    }
4308
4309    pub fn buffer_line_for_row(
4310        &self,
4311        row: MultiBufferRow,
4312    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4313        let mut cursor = self.cursor::<Point>();
4314        let point = Point::new(row.0, 0);
4315        cursor.seek(&point);
4316        let region = cursor.region()?;
4317        let overshoot = point.min(region.range.end) - region.range.start;
4318        let buffer_point = region.buffer_range.start + overshoot;
4319        if buffer_point.row > region.buffer_range.end.row {
4320            return None;
4321        }
4322        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4323        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4324            .min(region.buffer_range.end);
4325        Some((region.buffer, line_start..line_end))
4326    }
4327
4328    pub fn max_point(&self) -> Point {
4329        self.text_summary().lines
4330    }
4331
4332    pub fn max_row(&self) -> MultiBufferRow {
4333        MultiBufferRow(self.text_summary().lines.row)
4334    }
4335
4336    pub fn text_summary(&self) -> TextSummary {
4337        self.diff_transforms.summary().output
4338    }
4339
4340    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4341    where
4342        D: TextDimension,
4343        O: ToOffset,
4344    {
4345        let range = range.start.to_offset(self)..range.end.to_offset(self);
4346        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4347        cursor.seek(&range.start, Bias::Right, &());
4348
4349        let Some(first_transform) = cursor.item() else {
4350            return D::from_text_summary(&TextSummary::default());
4351        };
4352
4353        let diff_transform_start = cursor.start().0;
4354        let diff_transform_end = cursor.end(&()).0;
4355        let diff_start = range.start;
4356        let start_overshoot = diff_start - diff_transform_start;
4357        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4358
4359        let mut result = match first_transform {
4360            DiffTransform::BufferContent { .. } => {
4361                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4362                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4363                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4364            }
4365            DiffTransform::DeletedHunk {
4366                buffer_id,
4367                base_text_byte_range,
4368                has_trailing_newline,
4369                ..
4370            } => {
4371                let buffer_start = base_text_byte_range.start + start_overshoot;
4372                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4373                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4374                    panic!("{:?} is in non-existent deleted hunk", range.start)
4375                };
4376
4377                let include_trailing_newline =
4378                    *has_trailing_newline && range.end >= diff_transform_end;
4379                if include_trailing_newline {
4380                    buffer_end -= 1;
4381                }
4382
4383                let mut summary =
4384                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4385
4386                if include_trailing_newline {
4387                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4388                }
4389
4390                summary
4391            }
4392        };
4393        if range.end < diff_transform_end {
4394            return result;
4395        }
4396
4397        cursor.next(&());
4398        result.add_assign(&D::from_text_summary(&cursor.summary(
4399            &range.end,
4400            Bias::Right,
4401            &(),
4402        )));
4403
4404        let Some(last_transform) = cursor.item() else {
4405            return result;
4406        };
4407
4408        let overshoot = range.end - cursor.start().0;
4409        let suffix = match last_transform {
4410            DiffTransform::BufferContent { .. } => {
4411                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4412                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4413            }
4414            DiffTransform::DeletedHunk {
4415                base_text_byte_range,
4416                buffer_id,
4417                has_trailing_newline,
4418                ..
4419            } => {
4420                let buffer_end = base_text_byte_range.start + overshoot;
4421                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4422                    panic!("{:?} is in non-existent deleted hunk", range.end)
4423                };
4424
4425                let mut suffix = base_text
4426                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4427                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4428                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4429                }
4430                suffix
4431            }
4432        };
4433
4434        result.add_assign(&suffix);
4435        result
4436    }
4437
4438    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4439    where
4440        D: TextDimension,
4441    {
4442        // let mut range = range.start..range.end;
4443        let mut summary = D::zero(&());
4444        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4445        cursor.seek(&range.start, Bias::Right, &());
4446        if let Some(excerpt) = cursor.item() {
4447            let mut end_before_newline = cursor.end(&());
4448            if excerpt.has_trailing_newline {
4449                end_before_newline -= ExcerptOffset::new(1);
4450            }
4451
4452            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4453            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4454            let end_in_excerpt =
4455                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4456            summary.add_assign(
4457                &excerpt
4458                    .buffer
4459                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4460            );
4461
4462            if range.end > end_before_newline {
4463                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4464            }
4465
4466            cursor.next(&());
4467        }
4468
4469        if range.end > *cursor.start() {
4470            summary.add_assign(
4471                &cursor
4472                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4473                    .0,
4474            );
4475            if let Some(excerpt) = cursor.item() {
4476                range.end = cmp::max(*cursor.start(), range.end);
4477
4478                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4479                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4480                summary.add_assign(
4481                    &excerpt
4482                        .buffer
4483                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4484                );
4485            }
4486        }
4487
4488        summary
4489    }
4490
4491    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4492    where
4493        D: TextDimension + Ord + Sub<D, Output = D>,
4494    {
4495        self.summaries_for_anchors([anchor])[0]
4496    }
4497
4498    fn resolve_summary_for_anchor<D>(
4499        &self,
4500        anchor: &Anchor,
4501        excerpt_position: D,
4502        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4503    ) -> D
4504    where
4505        D: TextDimension + Ord + Sub<D, Output = D>,
4506    {
4507        loop {
4508            let transform_end_position = diff_transforms.end(&()).0 .0;
4509            let at_transform_end =
4510                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4511            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4512                diff_transforms.next(&());
4513                continue;
4514            }
4515
4516            let mut position = diff_transforms.start().1 .0;
4517            match diff_transforms.item() {
4518                Some(DiffTransform::DeletedHunk {
4519                    buffer_id,
4520                    base_text_byte_range,
4521                    ..
4522                }) => {
4523                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4524                        if let Some(base_text) =
4525                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4526                        {
4527                            if base_text.can_resolve(&diff_base_anchor) {
4528                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4529                                if base_text_offset >= base_text_byte_range.start
4530                                    && base_text_offset <= base_text_byte_range.end
4531                                {
4532                                    let position_in_hunk = base_text
4533                                        .text_summary_for_range::<D, _>(
4534                                            base_text_byte_range.start..base_text_offset,
4535                                        );
4536                                    position.add_assign(&position_in_hunk);
4537                                } else if at_transform_end {
4538                                    diff_transforms.next(&());
4539                                    continue;
4540                                }
4541                            }
4542                        }
4543                    }
4544                }
4545                _ => {
4546                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4547                        diff_transforms.next(&());
4548                        continue;
4549                    }
4550                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4551                    position.add_assign(&overshoot);
4552                }
4553            }
4554
4555            return position;
4556        }
4557    }
4558
4559    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4560        let mut cursor = self
4561            .excerpts
4562            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4563        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4564
4565        cursor.seek(&Some(locator), Bias::Left, &());
4566        if cursor.item().is_none() {
4567            cursor.next(&());
4568        }
4569
4570        let mut position = cursor.start().1;
4571        if let Some(excerpt) = cursor.item() {
4572            if excerpt.id == anchor.excerpt_id {
4573                let excerpt_buffer_start = excerpt
4574                    .buffer
4575                    .offset_for_anchor(&excerpt.range.context.start);
4576                let excerpt_buffer_end =
4577                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4578                let buffer_position = cmp::min(
4579                    excerpt_buffer_end,
4580                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4581                );
4582                if buffer_position > excerpt_buffer_start {
4583                    position.value += buffer_position - excerpt_buffer_start;
4584                }
4585            }
4586        }
4587        position
4588    }
4589
4590    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4591    where
4592        D: TextDimension + Ord + Sub<D, Output = D>,
4593        I: 'a + IntoIterator<Item = &'a Anchor>,
4594    {
4595        let mut anchors = anchors.into_iter().peekable();
4596        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4597        let mut diff_transforms_cursor = self
4598            .diff_transforms
4599            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4600        diff_transforms_cursor.next(&());
4601
4602        let mut summaries = Vec::new();
4603        while let Some(anchor) = anchors.peek() {
4604            let excerpt_id = anchor.excerpt_id;
4605            let excerpt_anchors = iter::from_fn(|| {
4606                let anchor = anchors.peek()?;
4607                if anchor.excerpt_id == excerpt_id {
4608                    Some(anchors.next().unwrap())
4609                } else {
4610                    None
4611                }
4612            });
4613
4614            let locator = self.excerpt_locator_for_id(excerpt_id);
4615            cursor.seek_forward(locator, Bias::Left, &());
4616            if cursor.item().is_none() {
4617                cursor.next(&());
4618            }
4619
4620            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4621            if let Some(excerpt) = cursor.item() {
4622                if excerpt.id != excerpt_id {
4623                    let position = self.resolve_summary_for_anchor(
4624                        &Anchor::min(),
4625                        excerpt_start_position,
4626                        &mut diff_transforms_cursor,
4627                    );
4628                    summaries.extend(excerpt_anchors.map(|_| position));
4629                    continue;
4630                }
4631                let excerpt_buffer_start =
4632                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4633                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4634                for (buffer_summary, anchor) in excerpt
4635                    .buffer
4636                    .summaries_for_anchors_with_payload::<D, _, _>(
4637                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4638                    )
4639                {
4640                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4641                    let mut position = excerpt_start_position;
4642                    if summary > excerpt_buffer_start {
4643                        position.add_assign(&(summary - excerpt_buffer_start));
4644                    }
4645
4646                    if position > diff_transforms_cursor.start().0 .0 {
4647                        diff_transforms_cursor.seek_forward(
4648                            &ExcerptDimension(position),
4649                            Bias::Left,
4650                            &(),
4651                        );
4652                    }
4653
4654                    summaries.push(self.resolve_summary_for_anchor(
4655                        anchor,
4656                        position,
4657                        &mut diff_transforms_cursor,
4658                    ));
4659                }
4660            } else {
4661                diff_transforms_cursor.seek_forward(
4662                    &ExcerptDimension(excerpt_start_position),
4663                    Bias::Left,
4664                    &(),
4665                );
4666                let position = self.resolve_summary_for_anchor(
4667                    &Anchor::max(),
4668                    excerpt_start_position,
4669                    &mut diff_transforms_cursor,
4670                );
4671                summaries.extend(excerpt_anchors.map(|_| position));
4672            }
4673        }
4674
4675        summaries
4676    }
4677
4678    pub fn dimensions_from_points<'a, D>(
4679        &'a self,
4680        points: impl 'a + IntoIterator<Item = Point>,
4681    ) -> impl 'a + Iterator<Item = D>
4682    where
4683        D: TextDimension + Sub<D, Output = D>,
4684    {
4685        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4686        cursor.seek(&DimensionPair {
4687            key: Point::default(),
4688            value: None,
4689        });
4690        let mut points = points.into_iter();
4691        iter::from_fn(move || {
4692            let point = points.next()?;
4693
4694            cursor.seek_forward(&DimensionPair {
4695                key: point,
4696                value: None,
4697            });
4698
4699            if let Some(region) = cursor.region() {
4700                let overshoot = point - region.range.start.key;
4701                let buffer_point = region.buffer_range.start.key + overshoot;
4702                let mut position = region.range.start.value.unwrap();
4703                position.add_assign(
4704                    &region
4705                        .buffer
4706                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4707                );
4708                return Some(position);
4709            } else {
4710                return Some(D::from_text_summary(&self.text_summary()));
4711            }
4712        })
4713    }
4714
4715    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4716    where
4717        I: 'a + IntoIterator<Item = &'a Anchor>,
4718    {
4719        let mut anchors = anchors.into_iter().enumerate().peekable();
4720        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4721        cursor.next(&());
4722
4723        let mut result = Vec::new();
4724
4725        while let Some((_, anchor)) = anchors.peek() {
4726            let old_excerpt_id = anchor.excerpt_id;
4727
4728            // Find the location where this anchor's excerpt should be.
4729            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4730            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4731
4732            if cursor.item().is_none() {
4733                cursor.next(&());
4734            }
4735
4736            let next_excerpt = cursor.item();
4737            let prev_excerpt = cursor.prev_item();
4738
4739            // Process all of the anchors for this excerpt.
4740            while let Some((_, anchor)) = anchors.peek() {
4741                if anchor.excerpt_id != old_excerpt_id {
4742                    break;
4743                }
4744                let (anchor_ix, anchor) = anchors.next().unwrap();
4745                let mut anchor = *anchor;
4746
4747                // Leave min and max anchors unchanged if invalid or
4748                // if the old excerpt still exists at this location
4749                let mut kept_position = next_excerpt
4750                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4751                    || old_excerpt_id == ExcerptId::max()
4752                    || old_excerpt_id == ExcerptId::min();
4753
4754                // If the old excerpt no longer exists at this location, then attempt to
4755                // find an equivalent position for this anchor in an adjacent excerpt.
4756                if !kept_position {
4757                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4758                        if excerpt.contains(&anchor) {
4759                            anchor.excerpt_id = excerpt.id;
4760                            kept_position = true;
4761                            break;
4762                        }
4763                    }
4764                }
4765
4766                // If there's no adjacent excerpt that contains the anchor's position,
4767                // then report that the anchor has lost its position.
4768                if !kept_position {
4769                    anchor = if let Some(excerpt) = next_excerpt {
4770                        let mut text_anchor = excerpt
4771                            .range
4772                            .context
4773                            .start
4774                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4775                        if text_anchor
4776                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4777                            .is_gt()
4778                        {
4779                            text_anchor = excerpt.range.context.end;
4780                        }
4781                        Anchor {
4782                            buffer_id: Some(excerpt.buffer_id),
4783                            excerpt_id: excerpt.id,
4784                            text_anchor,
4785                            diff_base_anchor: None,
4786                        }
4787                    } else if let Some(excerpt) = prev_excerpt {
4788                        let mut text_anchor = excerpt
4789                            .range
4790                            .context
4791                            .end
4792                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4793                        if text_anchor
4794                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4795                            .is_lt()
4796                        {
4797                            text_anchor = excerpt.range.context.start;
4798                        }
4799                        Anchor {
4800                            buffer_id: Some(excerpt.buffer_id),
4801                            excerpt_id: excerpt.id,
4802                            text_anchor,
4803                            diff_base_anchor: None,
4804                        }
4805                    } else if anchor.text_anchor.bias == Bias::Left {
4806                        Anchor::min()
4807                    } else {
4808                        Anchor::max()
4809                    };
4810                }
4811
4812                result.push((anchor_ix, anchor, kept_position));
4813            }
4814        }
4815        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4816        result
4817    }
4818
4819    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4820        self.anchor_at(position, Bias::Left)
4821    }
4822
4823    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4824        self.anchor_at(position, Bias::Right)
4825    }
4826
4827    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4828        let offset = position.to_offset(self);
4829
4830        // Find the given position in the diff transforms. Determine the corresponding
4831        // offset in the excerpts, and whether the position is within a deleted hunk.
4832        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4833        diff_transforms.seek(&offset, Bias::Right, &());
4834
4835        if offset == diff_transforms.start().0 && bias == Bias::Left {
4836            if let Some(prev_item) = diff_transforms.prev_item() {
4837                match prev_item {
4838                    DiffTransform::DeletedHunk { .. } => {
4839                        diff_transforms.prev(&());
4840                    }
4841                    _ => {}
4842                }
4843            }
4844        }
4845        let offset_in_transform = offset - diff_transforms.start().0;
4846        let mut excerpt_offset = diff_transforms.start().1;
4847        let mut diff_base_anchor = None;
4848        if let Some(DiffTransform::DeletedHunk {
4849            buffer_id,
4850            base_text_byte_range,
4851            has_trailing_newline,
4852            ..
4853        }) = diff_transforms.item()
4854        {
4855            let diff = self.diffs.get(buffer_id).expect("missing diff");
4856            if offset_in_transform > base_text_byte_range.len() {
4857                debug_assert!(*has_trailing_newline);
4858                bias = Bias::Right;
4859            } else {
4860                diff_base_anchor = Some(
4861                    diff.base_text()
4862                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4863                );
4864                bias = Bias::Left;
4865            }
4866        } else {
4867            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4868        };
4869
4870        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4871            return Anchor {
4872                buffer_id: Some(buffer_id),
4873                excerpt_id: *excerpt_id,
4874                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4875                diff_base_anchor,
4876            };
4877        }
4878
4879        let mut excerpts = self
4880            .excerpts
4881            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4882        excerpts.seek(&excerpt_offset, Bias::Right, &());
4883        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4884            excerpts.prev(&());
4885        }
4886        if let Some(excerpt) = excerpts.item() {
4887            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4888            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4889                overshoot -= 1;
4890                bias = Bias::Right;
4891            }
4892
4893            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4894            let text_anchor =
4895                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4896            Anchor {
4897                buffer_id: Some(excerpt.buffer_id),
4898                excerpt_id: excerpt.id,
4899                text_anchor,
4900                diff_base_anchor,
4901            }
4902        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4903            Anchor::min()
4904        } else {
4905            Anchor::max()
4906        }
4907    }
4908
4909    /// Returns an anchor for the given excerpt and text anchor,
4910    /// returns None if the excerpt_id is no longer valid.
4911    pub fn anchor_in_excerpt(
4912        &self,
4913        excerpt_id: ExcerptId,
4914        text_anchor: text::Anchor,
4915    ) -> Option<Anchor> {
4916        let locator = self.excerpt_locator_for_id(excerpt_id);
4917        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4918        cursor.seek(locator, Bias::Left, &());
4919        if let Some(excerpt) = cursor.item() {
4920            if excerpt.id == excerpt_id {
4921                let text_anchor = excerpt.clip_anchor(text_anchor);
4922                drop(cursor);
4923                return Some(Anchor {
4924                    buffer_id: Some(excerpt.buffer_id),
4925                    excerpt_id,
4926                    text_anchor,
4927                    diff_base_anchor: None,
4928                });
4929            }
4930        }
4931        None
4932    }
4933
4934    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4935        Some(self.excerpt(excerpt_id)?.range.context.clone())
4936    }
4937
4938    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4939        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4940            true
4941        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4942            excerpt.buffer.can_resolve(&anchor.text_anchor)
4943        } else {
4944            false
4945        }
4946    }
4947
4948    pub fn excerpts(
4949        &self,
4950    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4951        self.excerpts
4952            .iter()
4953            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4954    }
4955
4956    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4957        let excerpts = self.excerpts.cursor(&());
4958        let diff_transforms = self.diff_transforms.cursor(&());
4959        MultiBufferCursor {
4960            excerpts,
4961            diff_transforms,
4962            diffs: &self.diffs,
4963            cached_region: None,
4964        }
4965    }
4966
4967    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4968        let start_locator = self.excerpt_locator_for_id(id);
4969        let mut excerpts = self
4970            .excerpts
4971            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4972        excerpts.seek(&Some(start_locator), Bias::Left, &());
4973        excerpts.prev(&());
4974
4975        let mut diff_transforms = self
4976            .diff_transforms
4977            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4978        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4979        if diff_transforms.end(&()).1 < excerpts.start().1 {
4980            diff_transforms.next(&());
4981        }
4982
4983        let excerpt = excerpts.item()?;
4984        Some(MultiBufferExcerpt {
4985            excerpt,
4986            offset: diff_transforms.start().0 .0,
4987            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4988            excerpt_offset: excerpts.start().1.clone(),
4989            diff_transforms,
4990        })
4991    }
4992
4993    pub fn excerpt_boundaries_in_range<R, T>(
4994        &self,
4995        range: R,
4996    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4997    where
4998        R: RangeBounds<T>,
4999        T: ToOffset,
5000    {
5001        let start_offset;
5002        let start = match range.start_bound() {
5003            Bound::Included(start) => {
5004                start_offset = start.to_offset(self);
5005                Bound::Included(start_offset)
5006            }
5007            Bound::Excluded(_) => {
5008                panic!("not supported")
5009            }
5010            Bound::Unbounded => {
5011                start_offset = 0;
5012                Bound::Unbounded
5013            }
5014        };
5015        let end = match range.end_bound() {
5016            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5017            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5018            Bound::Unbounded => Bound::Unbounded,
5019        };
5020        let bounds = (start, end);
5021
5022        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5023        cursor.seek(&DimensionPair {
5024            key: start_offset,
5025            value: None,
5026        });
5027
5028        if cursor
5029            .region()
5030            .is_some_and(|region| bounds.contains(&region.range.start.key))
5031        {
5032            cursor.prev_excerpt();
5033        } else {
5034            cursor.seek_to_start_of_current_excerpt();
5035        }
5036        let mut prev_region = cursor.region();
5037
5038        cursor.next_excerpt();
5039
5040        let mut visited_end = false;
5041        iter::from_fn(move || loop {
5042            if self.singleton {
5043                return None;
5044            }
5045
5046            let next_region = cursor.region();
5047            cursor.next_excerpt();
5048
5049            let next_region_start = if let Some(region) = &next_region {
5050                if !bounds.contains(&region.range.start.key) {
5051                    prev_region = next_region;
5052                    continue;
5053                }
5054                region.range.start.value.unwrap()
5055            } else {
5056                if !bounds.contains(&self.len()) {
5057                    return None;
5058                }
5059                self.max_point()
5060            };
5061            let next_region_end = if let Some(region) = cursor.region() {
5062                region.range.start.value.unwrap()
5063            } else {
5064                self.max_point()
5065            };
5066
5067            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5068                id: region.excerpt.id,
5069                buffer: region.excerpt.buffer.clone(),
5070                buffer_id: region.excerpt.buffer_id,
5071                range: region.excerpt.range.clone(),
5072                end_row: MultiBufferRow(next_region_start.row),
5073            });
5074
5075            let next = next_region.as_ref().map(|region| ExcerptInfo {
5076                id: region.excerpt.id,
5077                buffer: region.excerpt.buffer.clone(),
5078                buffer_id: region.excerpt.buffer_id,
5079                range: region.excerpt.range.clone(),
5080                end_row: if region.excerpt.has_trailing_newline {
5081                    MultiBufferRow(next_region_end.row - 1)
5082                } else {
5083                    MultiBufferRow(next_region_end.row)
5084                },
5085            });
5086
5087            if next.is_none() {
5088                if visited_end {
5089                    return None;
5090                } else {
5091                    visited_end = true;
5092                }
5093            }
5094
5095            let row = MultiBufferRow(next_region_start.row);
5096
5097            prev_region = next_region;
5098
5099            return Some(ExcerptBoundary { row, prev, next });
5100        })
5101    }
5102
5103    pub fn edit_count(&self) -> usize {
5104        self.edit_count
5105    }
5106
5107    pub fn non_text_state_update_count(&self) -> usize {
5108        self.non_text_state_update_count
5109    }
5110
5111    /// Returns the smallest enclosing bracket ranges containing the given range or
5112    /// None if no brackets contain range or the range is not contained in a single
5113    /// excerpt
5114    ///
5115    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5116    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5117        &self,
5118        range: Range<T>,
5119        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5120    ) -> Option<(Range<usize>, Range<usize>)> {
5121        let range = range.start.to_offset(self)..range.end.to_offset(self);
5122        let mut excerpt = self.excerpt_containing(range.clone())?;
5123        let buffer = excerpt.buffer();
5124        let excerpt_buffer_range = excerpt.buffer_range();
5125
5126        // Filter to ranges contained in the excerpt
5127        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5128            excerpt_buffer_range.contains(&open.start)
5129                && excerpt_buffer_range.contains(&close.end)
5130                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5131        };
5132
5133        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5134            excerpt.map_range_to_buffer(range),
5135            Some(&range_filter),
5136        )?;
5137
5138        Some((
5139            excerpt.map_range_from_buffer(open),
5140            excerpt.map_range_from_buffer(close),
5141        ))
5142    }
5143
5144    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5145    /// not contained in a single excerpt
5146    pub fn enclosing_bracket_ranges<T: ToOffset>(
5147        &self,
5148        range: Range<T>,
5149    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5150        let range = range.start.to_offset(self)..range.end.to_offset(self);
5151        let mut excerpt = self.excerpt_containing(range.clone())?;
5152
5153        Some(
5154            excerpt
5155                .buffer()
5156                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5157                .filter_map(move |pair| {
5158                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5159                        Some((
5160                            excerpt.map_range_from_buffer(pair.open_range),
5161                            excerpt.map_range_from_buffer(pair.close_range),
5162                        ))
5163                    } else {
5164                        None
5165                    }
5166                }),
5167        )
5168    }
5169
5170    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5171    /// not contained in a single excerpt
5172    pub fn text_object_ranges<T: ToOffset>(
5173        &self,
5174        range: Range<T>,
5175        options: TreeSitterOptions,
5176    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5177        let range = range.start.to_offset(self)..range.end.to_offset(self);
5178        self.excerpt_containing(range.clone())
5179            .map(|mut excerpt| {
5180                excerpt
5181                    .buffer()
5182                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5183                    .filter_map(move |(range, text_object)| {
5184                        if excerpt.contains_buffer_range(range.clone()) {
5185                            Some((excerpt.map_range_from_buffer(range), text_object))
5186                        } else {
5187                            None
5188                        }
5189                    })
5190            })
5191            .into_iter()
5192            .flatten()
5193    }
5194
5195    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5196    /// not contained in a single excerpt
5197    pub fn bracket_ranges<T: ToOffset>(
5198        &self,
5199        range: Range<T>,
5200    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5201        let range = range.start.to_offset(self)..range.end.to_offset(self);
5202        let mut excerpt = self.excerpt_containing(range.clone())?;
5203
5204        Some(
5205            excerpt
5206                .buffer()
5207                .bracket_ranges(excerpt.map_range_to_buffer(range))
5208                .filter_map(move |pair| {
5209                    let buffer_range = pair.open_range.start..pair.close_range.end;
5210                    if excerpt.contains_buffer_range(buffer_range) {
5211                        Some((
5212                            excerpt.map_range_from_buffer(pair.open_range),
5213                            excerpt.map_range_from_buffer(pair.close_range),
5214                        ))
5215                    } else {
5216                        None
5217                    }
5218                }),
5219        )
5220    }
5221
5222    pub fn redacted_ranges<'a, T: ToOffset>(
5223        &'a self,
5224        range: Range<T>,
5225        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5226    ) -> impl Iterator<Item = Range<usize>> + 'a {
5227        let range = range.start.to_offset(self)..range.end.to_offset(self);
5228        self.lift_buffer_metadata(range, move |buffer, range| {
5229            if redaction_enabled(buffer.file()) {
5230                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5231            } else {
5232                None
5233            }
5234        })
5235        .map(|(range, _, _)| range)
5236    }
5237
5238    pub fn runnable_ranges(
5239        &self,
5240        range: Range<Anchor>,
5241    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5242        let range = range.start.to_offset(self)..range.end.to_offset(self);
5243        self.lift_buffer_metadata(range, move |buffer, range| {
5244            Some(
5245                buffer
5246                    .runnable_ranges(range.clone())
5247                    .filter(move |runnable| {
5248                        runnable.run_range.start >= range.start
5249                            && runnable.run_range.end < range.end
5250                    })
5251                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5252            )
5253        })
5254        .map(|(run_range, runnable, _)| language::RunnableRange {
5255            run_range,
5256            ..runnable
5257        })
5258    }
5259
5260    pub fn line_indents(
5261        &self,
5262        start_row: MultiBufferRow,
5263        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5264    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5265        let max_point = self.max_point();
5266        let mut cursor = self.cursor::<Point>();
5267        cursor.seek(&Point::new(start_row.0, 0));
5268        iter::from_fn(move || {
5269            let mut region = cursor.region()?;
5270            while !buffer_filter(&region.excerpt.buffer) {
5271                cursor.next();
5272                region = cursor.region()?;
5273            }
5274            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5275            let buffer_start_row =
5276                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5277
5278            let buffer_end_row = if region.is_main_buffer
5279                && (region.has_trailing_newline || region.range.end == max_point)
5280            {
5281                region.buffer_range.end.row
5282            } else {
5283                region.buffer_range.end.row.saturating_sub(1)
5284            };
5285
5286            let line_indents = region
5287                .buffer
5288                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5289            cursor.next();
5290            return Some(line_indents.map(move |(buffer_row, indent)| {
5291                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5292                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5293            }));
5294        })
5295        .flatten()
5296    }
5297
5298    pub fn reversed_line_indents(
5299        &self,
5300        end_row: MultiBufferRow,
5301        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5302    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5303        let max_point = self.max_point();
5304        let mut cursor = self.cursor::<Point>();
5305        cursor.seek(&Point::new(end_row.0, 0));
5306        iter::from_fn(move || {
5307            let mut region = cursor.region()?;
5308            while !buffer_filter(&region.excerpt.buffer) {
5309                cursor.prev();
5310                region = cursor.region()?;
5311            }
5312
5313            let buffer_start_row = region.buffer_range.start.row;
5314            let buffer_end_row = if region.is_main_buffer
5315                && (region.has_trailing_newline || region.range.end == max_point)
5316            {
5317                region.buffer_range.end.row + 1
5318            } else {
5319                region.buffer_range.end.row
5320            };
5321
5322            let overshoot = end_row.0 - region.range.start.row;
5323            let buffer_end_row =
5324                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5325
5326            let line_indents = region
5327                .buffer
5328                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5329            cursor.prev();
5330            return Some(line_indents.map(move |(buffer_row, indent)| {
5331                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5332                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5333            }));
5334        })
5335        .flatten()
5336    }
5337
5338    pub async fn enclosing_indent(
5339        &self,
5340        mut target_row: MultiBufferRow,
5341    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5342        let max_row = MultiBufferRow(self.max_point().row);
5343        if target_row >= max_row {
5344            return None;
5345        }
5346
5347        let mut target_indent = self.line_indent_for_row(target_row);
5348
5349        // If the current row is at the start of an indented block, we want to return this
5350        // block as the enclosing indent.
5351        if !target_indent.is_line_empty() && target_row < max_row {
5352            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5353            if !next_line_indent.is_line_empty()
5354                && target_indent.raw_len() < next_line_indent.raw_len()
5355            {
5356                target_indent = next_line_indent;
5357                target_row.0 += 1;
5358            }
5359        }
5360
5361        const SEARCH_ROW_LIMIT: u32 = 25000;
5362        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5363        const YIELD_INTERVAL: u32 = 100;
5364
5365        let mut accessed_row_counter = 0;
5366
5367        // If there is a blank line at the current row, search for the next non indented lines
5368        if target_indent.is_line_empty() {
5369            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5370            let end =
5371                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5372
5373            let mut non_empty_line_above = None;
5374            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5375                if row < start {
5376                    break;
5377                }
5378                accessed_row_counter += 1;
5379                if accessed_row_counter == YIELD_INTERVAL {
5380                    accessed_row_counter = 0;
5381                    yield_now().await;
5382                }
5383                if !indent.is_line_empty() {
5384                    non_empty_line_above = Some((row, indent));
5385                    break;
5386                }
5387            }
5388
5389            let mut non_empty_line_below = None;
5390            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5391                if row > end {
5392                    break;
5393                }
5394                accessed_row_counter += 1;
5395                if accessed_row_counter == YIELD_INTERVAL {
5396                    accessed_row_counter = 0;
5397                    yield_now().await;
5398                }
5399                if !indent.is_line_empty() {
5400                    non_empty_line_below = Some((row, indent));
5401                    break;
5402                }
5403            }
5404
5405            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5406                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5407                    if above_indent.raw_len() >= below_indent.raw_len() {
5408                        (above_row, above_indent)
5409                    } else {
5410                        (below_row, below_indent)
5411                    }
5412                }
5413                (Some(above), None) => above,
5414                (None, Some(below)) => below,
5415                _ => return None,
5416            };
5417
5418            target_indent = indent;
5419            target_row = row;
5420        }
5421
5422        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5423        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5424
5425        let mut start_indent = None;
5426        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5427            if row < start {
5428                break;
5429            }
5430            accessed_row_counter += 1;
5431            if accessed_row_counter == YIELD_INTERVAL {
5432                accessed_row_counter = 0;
5433                yield_now().await;
5434            }
5435            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5436                start_indent = Some((row, indent));
5437                break;
5438            }
5439        }
5440        let (start_row, start_indent_size) = start_indent?;
5441
5442        let mut end_indent = (end, None);
5443        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5444            if row > end {
5445                break;
5446            }
5447            accessed_row_counter += 1;
5448            if accessed_row_counter == YIELD_INTERVAL {
5449                accessed_row_counter = 0;
5450                yield_now().await;
5451            }
5452            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5453                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5454                break;
5455            }
5456        }
5457        let (end_row, end_indent_size) = end_indent;
5458
5459        let indent = if let Some(end_indent_size) = end_indent_size {
5460            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5461                start_indent_size
5462            } else {
5463                end_indent_size
5464            }
5465        } else {
5466            start_indent_size
5467        };
5468
5469        Some((start_row..end_row, indent))
5470    }
5471
5472    pub fn indent_guides_in_range<T: ToPoint>(
5473        &self,
5474        range: Range<T>,
5475        ignore_disabled_for_language: bool,
5476        cx: &App,
5477    ) -> impl Iterator<Item = IndentGuide> {
5478        let range = range.start.to_point(self)..range.end.to_point(self);
5479        let start_row = MultiBufferRow(range.start.row);
5480        let end_row = MultiBufferRow(range.end.row);
5481
5482        let mut row_indents = self.line_indents(start_row, |buffer| {
5483            let settings =
5484                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5485            settings.indent_guides.enabled || ignore_disabled_for_language
5486        });
5487
5488        let mut result = Vec::new();
5489        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5490
5491        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5492            if first_row > end_row {
5493                break;
5494            }
5495            let current_depth = indent_stack.len() as u32;
5496
5497            let settings =
5498                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5499            let tab_size = settings.tab_size.get() as u32;
5500
5501            // When encountering empty, continue until found useful line indent
5502            // then add to the indent stack with the depth found
5503            let mut found_indent = false;
5504            let mut last_row = first_row;
5505            if line_indent.is_line_empty() {
5506                while !found_indent {
5507                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5508                        break;
5509                    };
5510                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5511                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5512                        break;
5513                    }
5514
5515                    if new_line_indent.is_line_empty() {
5516                        continue;
5517                    }
5518                    last_row = target_row.min(end_row);
5519                    line_indent = new_line_indent;
5520                    found_indent = true;
5521                    break;
5522                }
5523            } else {
5524                found_indent = true
5525            }
5526
5527            let depth = if found_indent {
5528                line_indent.len(tab_size) / tab_size
5529                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5530            } else {
5531                current_depth
5532            };
5533
5534            match depth.cmp(&current_depth) {
5535                cmp::Ordering::Less => {
5536                    for _ in 0..(current_depth - depth) {
5537                        let mut indent = indent_stack.pop().unwrap();
5538                        if last_row != first_row {
5539                            // In this case, we landed on an empty row, had to seek forward,
5540                            // and discovered that the indent we where on is ending.
5541                            // This means that the last display row must
5542                            // be on line that ends this indent range, so we
5543                            // should display the range up to the first non-empty line
5544                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5545                        }
5546
5547                        result.push(indent)
5548                    }
5549                }
5550                cmp::Ordering::Greater => {
5551                    for next_depth in current_depth..depth {
5552                        indent_stack.push(IndentGuide {
5553                            buffer_id: buffer.remote_id(),
5554                            start_row: first_row,
5555                            end_row: last_row,
5556                            depth: next_depth,
5557                            tab_size,
5558                            settings: settings.indent_guides,
5559                        });
5560                    }
5561                }
5562                _ => {}
5563            }
5564
5565            for indent in indent_stack.iter_mut() {
5566                indent.end_row = last_row;
5567            }
5568        }
5569
5570        result.extend(indent_stack);
5571        result.into_iter()
5572    }
5573
5574    pub fn trailing_excerpt_update_count(&self) -> usize {
5575        self.trailing_excerpt_update_count
5576    }
5577
5578    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5579        self.point_to_buffer_offset(point)
5580            .and_then(|(buffer, _)| buffer.file())
5581    }
5582
5583    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5584        self.point_to_buffer_offset(point)
5585            .and_then(|(buffer, offset)| buffer.language_at(offset))
5586    }
5587
5588    pub fn settings_at<'a, T: ToOffset>(
5589        &'a self,
5590        point: T,
5591        cx: &'a App,
5592    ) -> Cow<'a, LanguageSettings> {
5593        let mut language = None;
5594        let mut file = None;
5595        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5596            language = buffer.language_at(offset);
5597            file = buffer.file();
5598        }
5599        language_settings(language.map(|l| l.name()), file, cx)
5600    }
5601
5602    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5603        self.point_to_buffer_offset(point)
5604            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5605    }
5606
5607    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5608        self.point_to_buffer_offset(point)
5609            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5610            .unwrap_or_default()
5611    }
5612
5613    pub fn language_indent_size_at<T: ToOffset>(
5614        &self,
5615        position: T,
5616        cx: &App,
5617    ) -> Option<IndentSize> {
5618        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5619        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5620    }
5621
5622    pub fn is_dirty(&self) -> bool {
5623        self.is_dirty
5624    }
5625
5626    pub fn has_deleted_file(&self) -> bool {
5627        self.has_deleted_file
5628    }
5629
5630    pub fn has_conflict(&self) -> bool {
5631        self.has_conflict
5632    }
5633
5634    pub fn has_diagnostics(&self) -> bool {
5635        self.excerpts
5636            .iter()
5637            .any(|excerpt| excerpt.buffer.has_diagnostics())
5638    }
5639
5640    pub fn diagnostic_group(
5641        &self,
5642        buffer_id: BufferId,
5643        group_id: usize,
5644    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5645        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5646            if buffer.remote_id() != buffer_id {
5647                return None;
5648            };
5649            Some(
5650                buffer
5651                    .diagnostic_group(group_id)
5652                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5653            )
5654        })
5655        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5656    }
5657
5658    pub fn diagnostics_in_range<'a, T>(
5659        &'a self,
5660        range: Range<T>,
5661    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5662    where
5663        T: 'a
5664            + text::ToOffset
5665            + text::FromAnchor
5666            + TextDimension
5667            + Ord
5668            + Sub<T, Output = T>
5669            + fmt::Debug,
5670    {
5671        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5672            Some(
5673                buffer
5674                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5675                    .map(|entry| (entry.range, entry.diagnostic)),
5676            )
5677        })
5678        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5679    }
5680
5681    pub fn syntax_ancestor<T: ToOffset>(
5682        &self,
5683        range: Range<T>,
5684    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5685        let range = range.start.to_offset(self)..range.end.to_offset(self);
5686        let mut excerpt = self.excerpt_containing(range.clone())?;
5687        let node = excerpt
5688            .buffer()
5689            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5690        let node_range = node.byte_range();
5691        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5692            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5693        } else {
5694            MultiOrSingleBufferOffsetRange::Single(node_range)
5695        };
5696        Some((node, range))
5697    }
5698
5699    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5700        let (excerpt_id, _, buffer) = self.as_singleton()?;
5701        let outline = buffer.outline(theme)?;
5702        Some(Outline::new(
5703            outline
5704                .items
5705                .into_iter()
5706                .flat_map(|item| {
5707                    Some(OutlineItem {
5708                        depth: item.depth,
5709                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5710                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5711                        text: item.text,
5712                        highlight_ranges: item.highlight_ranges,
5713                        name_ranges: item.name_ranges,
5714                        body_range: item.body_range.and_then(|body_range| {
5715                            Some(
5716                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5717                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5718                            )
5719                        }),
5720                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5721                            Some(
5722                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5723                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5724                            )
5725                        }),
5726                    })
5727                })
5728                .collect(),
5729        ))
5730    }
5731
5732    pub fn symbols_containing<T: ToOffset>(
5733        &self,
5734        offset: T,
5735        theme: Option<&SyntaxTheme>,
5736    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5737        let anchor = self.anchor_before(offset);
5738        let excerpt_id = anchor.excerpt_id;
5739        let excerpt = self.excerpt(excerpt_id)?;
5740        Some((
5741            excerpt.buffer_id,
5742            excerpt
5743                .buffer
5744                .symbols_containing(anchor.text_anchor, theme)
5745                .into_iter()
5746                .flatten()
5747                .flat_map(|item| {
5748                    Some(OutlineItem {
5749                        depth: item.depth,
5750                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5751                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5752                        text: item.text,
5753                        highlight_ranges: item.highlight_ranges,
5754                        name_ranges: item.name_ranges,
5755                        body_range: item.body_range.and_then(|body_range| {
5756                            Some(
5757                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5758                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5759                            )
5760                        }),
5761                        annotation_range: item.annotation_range.and_then(|body_range| {
5762                            Some(
5763                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5764                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5765                            )
5766                        }),
5767                    })
5768                })
5769                .collect(),
5770        ))
5771    }
5772
5773    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5774        if id == ExcerptId::min() {
5775            Locator::min_ref()
5776        } else if id == ExcerptId::max() {
5777            Locator::max_ref()
5778        } else {
5779            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5780            cursor.seek(&id, Bias::Left, &());
5781            if let Some(entry) = cursor.item() {
5782                if entry.id == id {
5783                    return &entry.locator;
5784                }
5785            }
5786            panic!("invalid excerpt id {:?}", id)
5787        }
5788    }
5789
5790    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5791    fn excerpt_locators_for_ids(
5792        &self,
5793        ids: impl IntoIterator<Item = ExcerptId>,
5794    ) -> SmallVec<[Locator; 1]> {
5795        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5796        sorted_ids.sort_unstable();
5797        let mut locators = SmallVec::new();
5798
5799        while sorted_ids.last() == Some(&ExcerptId::max()) {
5800            sorted_ids.pop();
5801            if let Some(mapping) = self.excerpt_ids.last() {
5802                locators.push(mapping.locator.clone());
5803            }
5804        }
5805
5806        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5807        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5808            sorted_ids.next();
5809            if let Some(mapping) = self.excerpt_ids.first() {
5810                locators.push(mapping.locator.clone());
5811            }
5812        }
5813
5814        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5815        for id in sorted_ids {
5816            if cursor.seek_forward(&id, Bias::Left, &()) {
5817                locators.push(cursor.item().unwrap().locator.clone());
5818            } else {
5819                panic!("invalid excerpt id {:?}", id);
5820            }
5821        }
5822
5823        locators.sort_unstable();
5824        locators
5825    }
5826
5827    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5828        Some(self.excerpt(excerpt_id)?.buffer_id)
5829    }
5830
5831    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5832        Some(&self.excerpt(excerpt_id)?.buffer)
5833    }
5834
5835    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5836        let mut cursor = self
5837            .excerpts
5838            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5839        let locator = self.excerpt_locator_for_id(excerpt_id);
5840        if cursor.seek(&Some(locator), Bias::Left, &()) {
5841            let start = cursor.start().1.clone();
5842            let end = cursor.end(&()).1;
5843            let mut diff_transforms = self
5844                .diff_transforms
5845                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5846            diff_transforms.seek(&start, Bias::Left, &());
5847            let overshoot = start.0 - diff_transforms.start().0 .0;
5848            let start = diff_transforms.start().1 .0 + overshoot;
5849            diff_transforms.seek(&end, Bias::Right, &());
5850            let overshoot = end.0 - diff_transforms.start().0 .0;
5851            let end = diff_transforms.start().1 .0 + overshoot;
5852            Some(start..end)
5853        } else {
5854            None
5855        }
5856    }
5857
5858    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5859        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5860        let locator = self.excerpt_locator_for_id(excerpt_id);
5861        if cursor.seek(&Some(locator), Bias::Left, &()) {
5862            if let Some(excerpt) = cursor.item() {
5863                return Some(excerpt.range.context.clone());
5864            }
5865        }
5866        None
5867    }
5868
5869    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5870        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5871        let locator = self.excerpt_locator_for_id(excerpt_id);
5872        cursor.seek(&Some(locator), Bias::Left, &());
5873        if let Some(excerpt) = cursor.item() {
5874            if excerpt.id == excerpt_id {
5875                return Some(excerpt);
5876            }
5877        }
5878        None
5879    }
5880
5881    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5882    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5883        let range = range.start.to_offset(self)..range.end.to_offset(self);
5884        let mut cursor = self.cursor::<usize>();
5885        cursor.seek(&range.start);
5886
5887        let start_excerpt = cursor.excerpt()?;
5888        if range.end != range.start {
5889            cursor.seek_forward(&range.end);
5890            if cursor.excerpt()?.id != start_excerpt.id {
5891                return None;
5892            }
5893        }
5894
5895        cursor.seek_to_start_of_current_excerpt();
5896        let region = cursor.region()?;
5897        let offset = region.range.start;
5898        let buffer_offset = region.buffer_range.start;
5899        let excerpt_offset = cursor.excerpts.start().clone();
5900        Some(MultiBufferExcerpt {
5901            diff_transforms: cursor.diff_transforms,
5902            excerpt: start_excerpt,
5903            offset,
5904            buffer_offset,
5905            excerpt_offset,
5906        })
5907    }
5908
5909    pub fn selections_in_range<'a>(
5910        &'a self,
5911        range: &'a Range<Anchor>,
5912        include_local: bool,
5913    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5914        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5915        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5916        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5917        cursor.seek(start_locator, Bias::Left, &());
5918        cursor
5919            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5920            .flat_map(move |excerpt| {
5921                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5922                if excerpt.id == range.start.excerpt_id {
5923                    query_range.start = range.start.text_anchor;
5924                }
5925                if excerpt.id == range.end.excerpt_id {
5926                    query_range.end = range.end.text_anchor;
5927                }
5928
5929                excerpt
5930                    .buffer
5931                    .selections_in_range(query_range, include_local)
5932                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5933                        selections.map(move |selection| {
5934                            let mut start = Anchor {
5935                                buffer_id: Some(excerpt.buffer_id),
5936                                excerpt_id: excerpt.id,
5937                                text_anchor: selection.start,
5938                                diff_base_anchor: None,
5939                            };
5940                            let mut end = Anchor {
5941                                buffer_id: Some(excerpt.buffer_id),
5942                                excerpt_id: excerpt.id,
5943                                text_anchor: selection.end,
5944                                diff_base_anchor: None,
5945                            };
5946                            if range.start.cmp(&start, self).is_gt() {
5947                                start = range.start;
5948                            }
5949                            if range.end.cmp(&end, self).is_lt() {
5950                                end = range.end;
5951                            }
5952
5953                            (
5954                                replica_id,
5955                                line_mode,
5956                                cursor_shape,
5957                                Selection {
5958                                    id: selection.id,
5959                                    start,
5960                                    end,
5961                                    reversed: selection.reversed,
5962                                    goal: selection.goal,
5963                                },
5964                            )
5965                        })
5966                    })
5967            })
5968    }
5969
5970    pub fn show_headers(&self) -> bool {
5971        self.show_headers
5972    }
5973
5974    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5975        self.diffs.get(&buffer_id)
5976    }
5977}
5978
5979#[cfg(any(test, feature = "test-support"))]
5980impl MultiBufferSnapshot {
5981    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5982        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5983        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5984        start..end
5985    }
5986
5987    #[cfg(any(test, feature = "test-support"))]
5988    fn check_invariants(&self) {
5989        let excerpts = self.excerpts.items(&());
5990        let excerpt_ids = self.excerpt_ids.items(&());
5991
5992        for (ix, excerpt) in excerpts.iter().enumerate() {
5993            if ix == 0 {
5994                if excerpt.locator <= Locator::min() {
5995                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5996                }
5997            } else if excerpt.locator <= excerpts[ix - 1].locator {
5998                panic!("excerpts are out-of-order: {:?}", excerpts);
5999            }
6000        }
6001
6002        for (ix, entry) in excerpt_ids.iter().enumerate() {
6003            if ix == 0 {
6004                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6005                    panic!("invalid first excerpt id {:?}", entry.id);
6006                }
6007            } else if entry.id <= excerpt_ids[ix - 1].id {
6008                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6009            }
6010        }
6011
6012        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6013            panic!(
6014                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6015                self.excerpts.summary().text.len,
6016                self.diff_transforms.summary().input,
6017                self.diff_transforms.items(&()),
6018            );
6019        }
6020
6021        let mut prev_transform: Option<&DiffTransform> = None;
6022        for item in self.diff_transforms.iter() {
6023            if let DiffTransform::BufferContent {
6024                summary,
6025                inserted_hunk_info,
6026            } = item
6027            {
6028                if let Some(DiffTransform::BufferContent {
6029                    inserted_hunk_info: prev_inserted_hunk_info,
6030                    ..
6031                }) = prev_transform
6032                {
6033                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6034                        panic!(
6035                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6036                            self.diff_transforms.items(&()));
6037                    }
6038                }
6039                if summary.len == 0 && !self.is_empty() {
6040                    panic!("empty buffer content transform");
6041                }
6042            }
6043            prev_transform = Some(item);
6044        }
6045    }
6046}
6047
6048impl<'a, D> MultiBufferCursor<'a, D>
6049where
6050    D: TextDimension + Ord + Sub<D, Output = D>,
6051{
6052    fn seek(&mut self, position: &D) {
6053        self.cached_region.take();
6054        self.diff_transforms
6055            .seek(&OutputDimension(*position), Bias::Right, &());
6056        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6057            self.diff_transforms.prev(&());
6058        }
6059
6060        let mut excerpt_position = self.diff_transforms.start().1 .0;
6061        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6062            let overshoot = *position - self.diff_transforms.start().0 .0;
6063            excerpt_position.add_assign(&overshoot);
6064        }
6065
6066        self.excerpts
6067            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6068        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6069            self.excerpts.prev(&());
6070        }
6071    }
6072
6073    fn seek_forward(&mut self, position: &D) {
6074        self.cached_region.take();
6075        self.diff_transforms
6076            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6077        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6078            self.diff_transforms.prev(&());
6079        }
6080
6081        let overshoot = *position - self.diff_transforms.start().0 .0;
6082        let mut excerpt_position = self.diff_transforms.start().1 .0;
6083        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6084            excerpt_position.add_assign(&overshoot);
6085        }
6086
6087        self.excerpts
6088            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6089        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6090            self.excerpts.prev(&());
6091        }
6092    }
6093
6094    fn next_excerpt(&mut self) {
6095        self.excerpts.next(&());
6096        self.seek_to_start_of_current_excerpt();
6097    }
6098
6099    fn prev_excerpt(&mut self) {
6100        self.excerpts.prev(&());
6101        self.seek_to_start_of_current_excerpt();
6102    }
6103
6104    fn seek_to_start_of_current_excerpt(&mut self) {
6105        self.cached_region.take();
6106        self.diff_transforms
6107            .seek(self.excerpts.start(), Bias::Left, &());
6108        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6109            && self.diff_transforms.start().1 < *self.excerpts.start()
6110            && self.diff_transforms.next_item().is_some()
6111        {
6112            self.diff_transforms.next(&());
6113        }
6114    }
6115
6116    fn next(&mut self) {
6117        self.cached_region.take();
6118        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6119            cmp::Ordering::Less => self.diff_transforms.next(&()),
6120            cmp::Ordering::Greater => self.excerpts.next(&()),
6121            cmp::Ordering::Equal => {
6122                self.diff_transforms.next(&());
6123                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6124                    || self.diff_transforms.item().is_none()
6125                {
6126                    self.excerpts.next(&());
6127                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6128                    self.diff_transforms.item()
6129                {
6130                    if self
6131                        .excerpts
6132                        .item()
6133                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6134                    {
6135                        self.excerpts.next(&());
6136                    }
6137                }
6138            }
6139        }
6140    }
6141
6142    fn prev(&mut self) {
6143        self.cached_region.take();
6144        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6145            cmp::Ordering::Less => self.excerpts.prev(&()),
6146            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6147            cmp::Ordering::Equal => {
6148                self.diff_transforms.prev(&());
6149                if self.diff_transforms.start().1 < *self.excerpts.start()
6150                    || self.diff_transforms.item().is_none()
6151                {
6152                    self.excerpts.prev(&());
6153                }
6154            }
6155        }
6156    }
6157
6158    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6159        if self.cached_region.is_none() {
6160            self.cached_region = self.build_region();
6161        }
6162        self.cached_region.clone()
6163    }
6164
6165    fn is_at_end_of_excerpt(&mut self) -> bool {
6166        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6167            return false;
6168        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6169            || self.diff_transforms.item().is_none()
6170        {
6171            return true;
6172        }
6173
6174        let next_transform = self.diff_transforms.next_item();
6175        next_transform.map_or(true, |next_transform| match next_transform {
6176            DiffTransform::BufferContent { .. } => true,
6177            DiffTransform::DeletedHunk { hunk_info, .. } => self
6178                .excerpts
6179                .item()
6180                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6181        })
6182    }
6183
6184    fn main_buffer_position(&self) -> Option<D> {
6185        let excerpt = self.excerpts.item()?;
6186        let buffer = &excerpt.buffer;
6187        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6188        let mut buffer_start = buffer_context_start;
6189        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6190        buffer_start.add_assign(&overshoot);
6191        Some(buffer_start)
6192    }
6193
6194    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6195        let excerpt = self.excerpts.item()?;
6196        match self.diff_transforms.item()? {
6197            DiffTransform::DeletedHunk {
6198                buffer_id,
6199                base_text_byte_range,
6200                has_trailing_newline,
6201                hunk_info,
6202                ..
6203            } => {
6204                let diff = self.diffs.get(&buffer_id)?;
6205                let buffer = diff.base_text();
6206                let mut rope_cursor = buffer.as_rope().cursor(0);
6207                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6208                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6209                let mut buffer_end = buffer_start;
6210                buffer_end.add_assign(&buffer_range_len);
6211                let start = self.diff_transforms.start().0 .0;
6212                let end = self.diff_transforms.end(&()).0 .0;
6213                return Some(MultiBufferRegion {
6214                    buffer,
6215                    excerpt,
6216                    has_trailing_newline: *has_trailing_newline,
6217                    is_main_buffer: false,
6218                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6219                        hunk_info.hunk_secondary_status,
6220                    )),
6221                    buffer_range: buffer_start..buffer_end,
6222                    range: start..end,
6223                });
6224            }
6225            DiffTransform::BufferContent {
6226                inserted_hunk_info, ..
6227            } => {
6228                let buffer = &excerpt.buffer;
6229                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6230
6231                let mut start = self.diff_transforms.start().0 .0;
6232                let mut buffer_start = buffer_context_start;
6233                if self.diff_transforms.start().1 < *self.excerpts.start() {
6234                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6235                    start.add_assign(&overshoot);
6236                } else {
6237                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6238                    buffer_start.add_assign(&overshoot);
6239                }
6240
6241                let mut end;
6242                let mut buffer_end;
6243                let has_trailing_newline;
6244                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6245                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6246                    end = self.diff_transforms.end(&()).0 .0;
6247                    buffer_end = buffer_context_start;
6248                    buffer_end.add_assign(&overshoot);
6249                    has_trailing_newline = false;
6250                } else {
6251                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6252                    end = self.diff_transforms.start().0 .0;
6253                    end.add_assign(&overshoot);
6254                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6255                    has_trailing_newline = excerpt.has_trailing_newline;
6256                };
6257
6258                Some(MultiBufferRegion {
6259                    buffer,
6260                    excerpt,
6261                    has_trailing_newline,
6262                    is_main_buffer: true,
6263                    diff_hunk_status: inserted_hunk_info
6264                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6265                    buffer_range: buffer_start..buffer_end,
6266                    range: start..end,
6267                })
6268            }
6269        }
6270    }
6271
6272    fn excerpt(&self) -> Option<&'a Excerpt> {
6273        self.excerpts.item()
6274    }
6275}
6276
6277impl History {
6278    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6279        self.transaction_depth += 1;
6280        if self.transaction_depth == 1 {
6281            let id = self.next_transaction_id.tick();
6282            self.undo_stack.push(Transaction {
6283                id,
6284                buffer_transactions: Default::default(),
6285                first_edit_at: now,
6286                last_edit_at: now,
6287                suppress_grouping: false,
6288            });
6289            Some(id)
6290        } else {
6291            None
6292        }
6293    }
6294
6295    fn end_transaction(
6296        &mut self,
6297        now: Instant,
6298        buffer_transactions: HashMap<BufferId, TransactionId>,
6299    ) -> bool {
6300        assert_ne!(self.transaction_depth, 0);
6301        self.transaction_depth -= 1;
6302        if self.transaction_depth == 0 {
6303            if buffer_transactions.is_empty() {
6304                self.undo_stack.pop();
6305                false
6306            } else {
6307                self.redo_stack.clear();
6308                let transaction = self.undo_stack.last_mut().unwrap();
6309                transaction.last_edit_at = now;
6310                for (buffer_id, transaction_id) in buffer_transactions {
6311                    transaction
6312                        .buffer_transactions
6313                        .entry(buffer_id)
6314                        .or_insert(transaction_id);
6315                }
6316                true
6317            }
6318        } else {
6319            false
6320        }
6321    }
6322
6323    fn push_transaction<'a, T>(
6324        &mut self,
6325        buffer_transactions: T,
6326        now: Instant,
6327        cx: &Context<MultiBuffer>,
6328    ) where
6329        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6330    {
6331        assert_eq!(self.transaction_depth, 0);
6332        let transaction = Transaction {
6333            id: self.next_transaction_id.tick(),
6334            buffer_transactions: buffer_transactions
6335                .into_iter()
6336                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6337                .collect(),
6338            first_edit_at: now,
6339            last_edit_at: now,
6340            suppress_grouping: false,
6341        };
6342        if !transaction.buffer_transactions.is_empty() {
6343            self.undo_stack.push(transaction);
6344            self.redo_stack.clear();
6345        }
6346    }
6347
6348    fn finalize_last_transaction(&mut self) {
6349        if let Some(transaction) = self.undo_stack.last_mut() {
6350            transaction.suppress_grouping = true;
6351        }
6352    }
6353
6354    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6355        if let Some(ix) = self
6356            .undo_stack
6357            .iter()
6358            .rposition(|transaction| transaction.id == transaction_id)
6359        {
6360            Some(self.undo_stack.remove(ix))
6361        } else if let Some(ix) = self
6362            .redo_stack
6363            .iter()
6364            .rposition(|transaction| transaction.id == transaction_id)
6365        {
6366            Some(self.redo_stack.remove(ix))
6367        } else {
6368            None
6369        }
6370    }
6371
6372    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6373        self.undo_stack
6374            .iter()
6375            .find(|transaction| transaction.id == transaction_id)
6376            .or_else(|| {
6377                self.redo_stack
6378                    .iter()
6379                    .find(|transaction| transaction.id == transaction_id)
6380            })
6381    }
6382
6383    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6384        self.undo_stack
6385            .iter_mut()
6386            .find(|transaction| transaction.id == transaction_id)
6387            .or_else(|| {
6388                self.redo_stack
6389                    .iter_mut()
6390                    .find(|transaction| transaction.id == transaction_id)
6391            })
6392    }
6393
6394    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6395        assert_eq!(self.transaction_depth, 0);
6396        if let Some(transaction) = self.undo_stack.pop() {
6397            self.redo_stack.push(transaction);
6398            self.redo_stack.last_mut()
6399        } else {
6400            None
6401        }
6402    }
6403
6404    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6405        assert_eq!(self.transaction_depth, 0);
6406        if let Some(transaction) = self.redo_stack.pop() {
6407            self.undo_stack.push(transaction);
6408            self.undo_stack.last_mut()
6409        } else {
6410            None
6411        }
6412    }
6413
6414    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6415        let ix = self
6416            .undo_stack
6417            .iter()
6418            .rposition(|transaction| transaction.id == transaction_id)?;
6419        let transaction = self.undo_stack.remove(ix);
6420        self.redo_stack.push(transaction);
6421        self.redo_stack.last()
6422    }
6423
6424    fn group(&mut self) -> Option<TransactionId> {
6425        let mut count = 0;
6426        let mut transactions = self.undo_stack.iter();
6427        if let Some(mut transaction) = transactions.next_back() {
6428            while let Some(prev_transaction) = transactions.next_back() {
6429                if !prev_transaction.suppress_grouping
6430                    && transaction.first_edit_at - prev_transaction.last_edit_at
6431                        <= self.group_interval
6432                {
6433                    transaction = prev_transaction;
6434                    count += 1;
6435                } else {
6436                    break;
6437                }
6438            }
6439        }
6440        self.group_trailing(count)
6441    }
6442
6443    fn group_until(&mut self, transaction_id: TransactionId) {
6444        let mut count = 0;
6445        for transaction in self.undo_stack.iter().rev() {
6446            if transaction.id == transaction_id {
6447                self.group_trailing(count);
6448                break;
6449            } else if transaction.suppress_grouping {
6450                break;
6451            } else {
6452                count += 1;
6453            }
6454        }
6455    }
6456
6457    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6458        let new_len = self.undo_stack.len() - n;
6459        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6460        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6461            if let Some(transaction) = transactions_to_merge.last() {
6462                last_transaction.last_edit_at = transaction.last_edit_at;
6463            }
6464            for to_merge in transactions_to_merge {
6465                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6466                    last_transaction
6467                        .buffer_transactions
6468                        .entry(*buffer_id)
6469                        .or_insert(*transaction_id);
6470                }
6471            }
6472        }
6473
6474        self.undo_stack.truncate(new_len);
6475        self.undo_stack.last().map(|t| t.id)
6476    }
6477}
6478
6479impl Excerpt {
6480    fn new(
6481        id: ExcerptId,
6482        locator: Locator,
6483        buffer_id: BufferId,
6484        buffer: BufferSnapshot,
6485        range: ExcerptRange<text::Anchor>,
6486        has_trailing_newline: bool,
6487    ) -> Self {
6488        Excerpt {
6489            id,
6490            locator,
6491            max_buffer_row: range.context.end.to_point(&buffer).row,
6492            text_summary: buffer
6493                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6494            buffer_id,
6495            buffer,
6496            range,
6497            has_trailing_newline,
6498        }
6499    }
6500
6501    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6502        let content_start = self.range.context.start.to_offset(&self.buffer);
6503        let chunks_start = content_start + range.start;
6504        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6505
6506        let footer_height = if self.has_trailing_newline
6507            && range.start <= self.text_summary.len
6508            && range.end > self.text_summary.len
6509        {
6510            1
6511        } else {
6512            0
6513        };
6514
6515        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6516
6517        ExcerptChunks {
6518            excerpt_id: self.id,
6519            content_chunks,
6520            footer_height,
6521        }
6522    }
6523
6524    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6525        let content_start = self.range.context.start.to_offset(&self.buffer);
6526        let chunks_start = content_start + range.start;
6527        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6528        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6529        excerpt_chunks.footer_height = if self.has_trailing_newline
6530            && range.start <= self.text_summary.len
6531            && range.end > self.text_summary.len
6532        {
6533            1
6534        } else {
6535            0
6536        };
6537    }
6538
6539    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6540        if text_anchor
6541            .cmp(&self.range.context.start, &self.buffer)
6542            .is_lt()
6543        {
6544            self.range.context.start
6545        } else if text_anchor
6546            .cmp(&self.range.context.end, &self.buffer)
6547            .is_gt()
6548        {
6549            self.range.context.end
6550        } else {
6551            text_anchor
6552        }
6553    }
6554
6555    fn contains(&self, anchor: &Anchor) -> bool {
6556        Some(self.buffer_id) == anchor.buffer_id
6557            && self
6558                .range
6559                .context
6560                .start
6561                .cmp(&anchor.text_anchor, &self.buffer)
6562                .is_le()
6563            && self
6564                .range
6565                .context
6566                .end
6567                .cmp(&anchor.text_anchor, &self.buffer)
6568                .is_ge()
6569    }
6570
6571    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6572    fn buffer_start_offset(&self) -> usize {
6573        self.range.context.start.to_offset(&self.buffer)
6574    }
6575
6576    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6577    fn buffer_end_offset(&self) -> usize {
6578        self.buffer_start_offset() + self.text_summary.len
6579    }
6580}
6581
6582impl<'a> MultiBufferExcerpt<'a> {
6583    pub fn id(&self) -> ExcerptId {
6584        self.excerpt.id
6585    }
6586
6587    pub fn buffer_id(&self) -> BufferId {
6588        self.excerpt.buffer_id
6589    }
6590
6591    pub fn start_anchor(&self) -> Anchor {
6592        Anchor {
6593            buffer_id: Some(self.excerpt.buffer_id),
6594            excerpt_id: self.excerpt.id,
6595            text_anchor: self.excerpt.range.context.start,
6596            diff_base_anchor: None,
6597        }
6598    }
6599
6600    pub fn end_anchor(&self) -> Anchor {
6601        Anchor {
6602            buffer_id: Some(self.excerpt.buffer_id),
6603            excerpt_id: self.excerpt.id,
6604            text_anchor: self.excerpt.range.context.end,
6605            diff_base_anchor: None,
6606        }
6607    }
6608
6609    pub fn buffer(&self) -> &'a BufferSnapshot {
6610        &self.excerpt.buffer
6611    }
6612
6613    pub fn buffer_range(&self) -> Range<usize> {
6614        self.buffer_offset
6615            ..self
6616                .excerpt
6617                .range
6618                .context
6619                .end
6620                .to_offset(&self.excerpt.buffer.text)
6621    }
6622
6623    pub fn start_offset(&self) -> usize {
6624        self.offset
6625    }
6626
6627    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6628    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6629        self.map_range_to_buffer(offset..offset).start
6630    }
6631
6632    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6633    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6634        self.diff_transforms
6635            .seek(&OutputDimension(range.start), Bias::Right, &());
6636        let start = self.map_offset_to_buffer_internal(range.start);
6637        let end = if range.end > range.start {
6638            self.diff_transforms
6639                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6640            self.map_offset_to_buffer_internal(range.end)
6641        } else {
6642            start
6643        };
6644        start..end
6645    }
6646
6647    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6648        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6649        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6650            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6651        };
6652        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6653        self.buffer_offset + offset_in_excerpt
6654    }
6655
6656    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6657    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6658        self.map_range_from_buffer(buffer_offset..buffer_offset)
6659            .start
6660    }
6661
6662    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6663    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6664        if buffer_range.start < self.buffer_offset {
6665            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6666            return buffer_range;
6667        }
6668        let overshoot = buffer_range.start - self.buffer_offset;
6669        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6670        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6671        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6672            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6673            return buffer_range;
6674        }
6675        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6676        let start = self.diff_transforms.start().0 .0 + overshoot;
6677
6678        let end = if buffer_range.end > buffer_range.start {
6679            let overshoot = buffer_range.end - self.buffer_offset;
6680            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6681            self.diff_transforms
6682                .seek_forward(&excerpt_offset, Bias::Right, &());
6683            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6684            self.diff_transforms.start().0 .0 + overshoot
6685        } else {
6686            start
6687        };
6688
6689        start..end
6690    }
6691
6692    /// Returns true if the entirety of the given range is in the buffer's excerpt
6693    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6694        range.start >= self.excerpt.buffer_start_offset()
6695            && range.end <= self.excerpt.buffer_end_offset()
6696    }
6697
6698    pub fn max_buffer_row(&self) -> u32 {
6699        self.excerpt.max_buffer_row
6700    }
6701}
6702
6703impl ExcerptId {
6704    pub fn min() -> Self {
6705        Self(0)
6706    }
6707
6708    pub fn max() -> Self {
6709        Self(usize::MAX)
6710    }
6711
6712    pub fn to_proto(&self) -> u64 {
6713        self.0 as _
6714    }
6715
6716    pub fn from_proto(proto: u64) -> Self {
6717        Self(proto as _)
6718    }
6719
6720    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6721        let a = snapshot.excerpt_locator_for_id(*self);
6722        let b = snapshot.excerpt_locator_for_id(*other);
6723        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6724    }
6725}
6726
6727impl From<ExcerptId> for usize {
6728    fn from(val: ExcerptId) -> Self {
6729        val.0
6730    }
6731}
6732
6733impl fmt::Debug for Excerpt {
6734    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6735        f.debug_struct("Excerpt")
6736            .field("id", &self.id)
6737            .field("locator", &self.locator)
6738            .field("buffer_id", &self.buffer_id)
6739            .field("range", &self.range)
6740            .field("text_summary", &self.text_summary)
6741            .field("has_trailing_newline", &self.has_trailing_newline)
6742            .finish()
6743    }
6744}
6745
6746impl sum_tree::Item for Excerpt {
6747    type Summary = ExcerptSummary;
6748
6749    fn summary(&self, _cx: &()) -> Self::Summary {
6750        let mut text = self.text_summary;
6751        if self.has_trailing_newline {
6752            text += TextSummary::from("\n");
6753        }
6754        ExcerptSummary {
6755            excerpt_id: self.id,
6756            excerpt_locator: self.locator.clone(),
6757            widest_line_number: self.max_buffer_row,
6758            text,
6759        }
6760    }
6761}
6762
6763impl sum_tree::Item for ExcerptIdMapping {
6764    type Summary = ExcerptId;
6765
6766    fn summary(&self, _cx: &()) -> Self::Summary {
6767        self.id
6768    }
6769}
6770
6771impl sum_tree::KeyedItem for ExcerptIdMapping {
6772    type Key = ExcerptId;
6773
6774    fn key(&self) -> Self::Key {
6775        self.id
6776    }
6777}
6778
6779impl DiffTransform {
6780    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6781        match self {
6782            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6783            DiffTransform::BufferContent {
6784                inserted_hunk_info, ..
6785            } => *inserted_hunk_info,
6786        }
6787    }
6788}
6789
6790impl sum_tree::Item for DiffTransform {
6791    type Summary = DiffTransformSummary;
6792
6793    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6794        match self {
6795            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6796                input: *summary,
6797                output: *summary,
6798            },
6799            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6800                input: TextSummary::default(),
6801                output: *summary,
6802            },
6803        }
6804    }
6805}
6806
6807impl DiffTransformSummary {
6808    fn excerpt_len(&self) -> ExcerptOffset {
6809        ExcerptOffset::new(self.input.len)
6810    }
6811}
6812
6813impl sum_tree::Summary for DiffTransformSummary {
6814    type Context = ();
6815
6816    fn zero(_: &Self::Context) -> Self {
6817        DiffTransformSummary {
6818            input: TextSummary::default(),
6819            output: TextSummary::default(),
6820        }
6821    }
6822
6823    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6824        self.input += &summary.input;
6825        self.output += &summary.output;
6826    }
6827}
6828
6829impl sum_tree::Summary for ExcerptId {
6830    type Context = ();
6831
6832    fn zero(_cx: &()) -> Self {
6833        Default::default()
6834    }
6835
6836    fn add_summary(&mut self, other: &Self, _: &()) {
6837        *self = *other;
6838    }
6839}
6840
6841impl sum_tree::Summary for ExcerptSummary {
6842    type Context = ();
6843
6844    fn zero(_cx: &()) -> Self {
6845        Default::default()
6846    }
6847
6848    fn add_summary(&mut self, summary: &Self, _: &()) {
6849        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6850        self.excerpt_locator = summary.excerpt_locator.clone();
6851        self.text.add_summary(&summary.text, &());
6852        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6853    }
6854}
6855
6856impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6857    fn zero(_cx: &()) -> Self {
6858        Default::default()
6859    }
6860
6861    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6862        self.value += summary.text.len;
6863    }
6864}
6865
6866impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6867    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6868        Ord::cmp(&self.value, &cursor_location.text.len)
6869    }
6870}
6871
6872impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6873    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6874        Ord::cmp(&Some(self), cursor_location)
6875    }
6876}
6877
6878impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6879    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6880        Ord::cmp(self, &cursor_location.excerpt_locator)
6881    }
6882}
6883
6884impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6885    fn zero(_cx: &()) -> Self {
6886        Default::default()
6887    }
6888
6889    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6890        self.value += summary.text.lines;
6891    }
6892}
6893
6894impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6895    for ExcerptDimension<D>
6896{
6897    fn zero(_: &()) -> Self {
6898        ExcerptDimension(D::default())
6899    }
6900
6901    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6902        self.0.add_assign(&D::from_text_summary(&summary.text))
6903    }
6904}
6905
6906impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6907    fn zero(_cx: &()) -> Self {
6908        Default::default()
6909    }
6910
6911    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6912        *self = Some(&summary.excerpt_locator);
6913    }
6914}
6915
6916impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6917    fn zero(_cx: &()) -> Self {
6918        Default::default()
6919    }
6920
6921    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6922        *self = Some(summary.excerpt_id);
6923    }
6924}
6925
6926#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6927struct ExcerptDimension<T>(T);
6928
6929#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6930struct OutputDimension<T>(T);
6931
6932impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6933    fn zero(_: &()) -> Self {
6934        ExcerptOffset::new(0)
6935    }
6936
6937    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6938        self.value += summary.input.len;
6939    }
6940}
6941
6942impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6943    fn zero(_: &()) -> Self {
6944        ExcerptPoint::new(0, 0)
6945    }
6946
6947    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6948        self.value += summary.input.lines;
6949    }
6950}
6951
6952impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6953    for ExcerptDimension<D>
6954{
6955    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6956        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6957    }
6958}
6959
6960impl<D: TextDimension + Ord>
6961    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6962    for ExcerptDimension<D>
6963{
6964    fn cmp(
6965        &self,
6966        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6967        _: &(),
6968    ) -> cmp::Ordering {
6969        Ord::cmp(&self.0, &cursor_location.1 .0)
6970    }
6971}
6972
6973impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6974    fn zero(_: &()) -> Self {
6975        ExcerptDimension(D::default())
6976    }
6977
6978    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6979        self.0.add_assign(&D::from_text_summary(&summary.input))
6980    }
6981}
6982
6983impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6984    fn zero(_: &()) -> Self {
6985        OutputDimension(D::default())
6986    }
6987
6988    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6989        self.0.add_assign(&D::from_text_summary(&summary.output))
6990    }
6991}
6992
6993impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6994    fn zero(_: &()) -> Self {
6995        TextSummary::default()
6996    }
6997
6998    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6999        *self += summary.output
7000    }
7001}
7002
7003impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7004    fn zero(_: &()) -> Self {
7005        0
7006    }
7007
7008    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7009        *self += summary.output.len
7010    }
7011}
7012
7013impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7014    fn zero(_: &()) -> Self {
7015        Point::new(0, 0)
7016    }
7017
7018    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7019        *self += summary.output.lines
7020    }
7021}
7022
7023impl MultiBufferRows<'_> {
7024    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7025        self.point = Point::new(row, 0);
7026        self.cursor.seek(&self.point);
7027    }
7028}
7029
7030impl Iterator for MultiBufferRows<'_> {
7031    type Item = RowInfo;
7032
7033    fn next(&mut self) -> Option<Self::Item> {
7034        if self.is_empty && self.point.row == 0 {
7035            self.point += Point::new(1, 0);
7036            return Some(RowInfo {
7037                buffer_id: None,
7038                buffer_row: Some(0),
7039                multibuffer_row: Some(MultiBufferRow(0)),
7040                diff_status: None,
7041            });
7042        }
7043
7044        let mut region = self.cursor.region()?;
7045        while self.point >= region.range.end {
7046            self.cursor.next();
7047            if let Some(next_region) = self.cursor.region() {
7048                region = next_region;
7049            } else {
7050                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7051                    let multibuffer_row = MultiBufferRow(self.point.row);
7052                    self.point += Point::new(1, 0);
7053                    let last_excerpt = self
7054                        .cursor
7055                        .excerpts
7056                        .item()
7057                        .or(self.cursor.excerpts.prev_item())?;
7058                    let last_row = last_excerpt
7059                        .range
7060                        .context
7061                        .end
7062                        .to_point(&last_excerpt.buffer)
7063                        .row;
7064                    return Some(RowInfo {
7065                        buffer_id: Some(last_excerpt.buffer_id),
7066                        buffer_row: Some(last_row),
7067                        multibuffer_row: Some(multibuffer_row),
7068                        diff_status: None,
7069                    });
7070                } else {
7071                    return None;
7072                }
7073            };
7074        }
7075
7076        let overshoot = self.point - region.range.start;
7077        let buffer_point = region.buffer_range.start + overshoot;
7078        let result = Some(RowInfo {
7079            buffer_id: Some(region.buffer.remote_id()),
7080            buffer_row: Some(buffer_point.row),
7081            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7082            diff_status: region
7083                .diff_hunk_status
7084                .filter(|_| self.point < region.range.end),
7085        });
7086        self.point += Point::new(1, 0);
7087        result
7088    }
7089}
7090
7091impl<'a> MultiBufferChunks<'a> {
7092    pub fn offset(&self) -> usize {
7093        self.range.start
7094    }
7095
7096    pub fn seek(&mut self, range: Range<usize>) {
7097        self.diff_transforms.seek(&range.end, Bias::Right, &());
7098        let mut excerpt_end = self.diff_transforms.start().1;
7099        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7100            let overshoot = range.end - self.diff_transforms.start().0;
7101            excerpt_end.value += overshoot;
7102        }
7103
7104        self.diff_transforms.seek(&range.start, Bias::Right, &());
7105        let mut excerpt_start = self.diff_transforms.start().1;
7106        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7107            let overshoot = range.start - self.diff_transforms.start().0;
7108            excerpt_start.value += overshoot;
7109        }
7110
7111        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7112        self.buffer_chunk.take();
7113        self.range = range;
7114    }
7115
7116    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7117        self.excerpt_offset_range = new_range.clone();
7118        self.excerpts.seek(&new_range.start, Bias::Right, &());
7119        if let Some(excerpt) = self.excerpts.item() {
7120            let excerpt_start = *self.excerpts.start();
7121            if let Some(excerpt_chunks) = self
7122                .excerpt_chunks
7123                .as_mut()
7124                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7125            {
7126                excerpt.seek_chunks(
7127                    excerpt_chunks,
7128                    (self.excerpt_offset_range.start - excerpt_start).value
7129                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7130                );
7131            } else {
7132                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7133                    (self.excerpt_offset_range.start - excerpt_start).value
7134                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7135                    self.language_aware,
7136                ));
7137            }
7138        } else {
7139            self.excerpt_chunks = None;
7140        }
7141    }
7142
7143    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7144        loop {
7145            if self.excerpt_offset_range.is_empty() {
7146                return None;
7147            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7148                self.excerpt_offset_range.start.value += chunk.text.len();
7149                return Some(chunk);
7150            } else {
7151                self.excerpts.next(&());
7152                let excerpt = self.excerpts.item()?;
7153                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7154                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7155                    self.language_aware,
7156                ));
7157            }
7158        }
7159    }
7160}
7161
7162impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7163    type Item = &'a str;
7164
7165    fn next(&mut self) -> Option<Self::Item> {
7166        let mut region = self.cursor.region()?;
7167        if self.offset == region.range.start {
7168            self.cursor.prev();
7169            region = self.cursor.region()?;
7170            let start_overshoot = self.start.saturating_sub(region.range.start);
7171            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7172                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7173            ));
7174        }
7175
7176        if self.offset == region.range.end && region.has_trailing_newline {
7177            self.offset -= 1;
7178            Some("\n")
7179        } else {
7180            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7181            self.offset -= chunk.len();
7182            Some(chunk)
7183        }
7184    }
7185}
7186
7187impl<'a> Iterator for MultiBufferChunks<'a> {
7188    type Item = Chunk<'a>;
7189
7190    fn next(&mut self) -> Option<Chunk<'a>> {
7191        if self.range.start >= self.range.end {
7192            return None;
7193        }
7194        if self.range.start == self.diff_transforms.end(&()).0 {
7195            self.diff_transforms.next(&());
7196        }
7197
7198        let diff_transform_start = self.diff_transforms.start().0;
7199        let diff_transform_end = self.diff_transforms.end(&()).0;
7200        debug_assert!(self.range.start < diff_transform_end);
7201
7202        let diff_transform = self.diff_transforms.item()?;
7203        match diff_transform {
7204            DiffTransform::BufferContent { .. } => {
7205                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7206                    chunk
7207                } else {
7208                    let chunk = self.next_excerpt_chunk().unwrap();
7209                    self.buffer_chunk.insert(chunk)
7210                };
7211
7212                let chunk_end = self.range.start + chunk.text.len();
7213                let diff_transform_end = diff_transform_end.min(self.range.end);
7214
7215                if diff_transform_end < chunk_end {
7216                    let (before, after) =
7217                        chunk.text.split_at(diff_transform_end - self.range.start);
7218                    self.range.start = diff_transform_end;
7219                    chunk.text = after;
7220                    Some(Chunk {
7221                        text: before,
7222                        ..chunk.clone()
7223                    })
7224                } else {
7225                    self.range.start = chunk_end;
7226                    self.buffer_chunk.take()
7227                }
7228            }
7229            DiffTransform::DeletedHunk {
7230                buffer_id,
7231                base_text_byte_range,
7232                has_trailing_newline,
7233                ..
7234            } => {
7235                let base_text_start =
7236                    base_text_byte_range.start + self.range.start - diff_transform_start;
7237                let base_text_end =
7238                    base_text_byte_range.start + self.range.end - diff_transform_start;
7239                let base_text_end = base_text_end.min(base_text_byte_range.end);
7240
7241                let mut chunks = if let Some((_, mut chunks)) = self
7242                    .diff_base_chunks
7243                    .take()
7244                    .filter(|(id, _)| id == buffer_id)
7245                {
7246                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7247                    {
7248                        chunks.seek(base_text_start..base_text_end);
7249                    }
7250                    chunks
7251                } else {
7252                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7253                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7254                };
7255
7256                let chunk = if let Some(chunk) = chunks.next() {
7257                    self.range.start += chunk.text.len();
7258                    self.diff_base_chunks = Some((*buffer_id, chunks));
7259                    chunk
7260                } else {
7261                    debug_assert!(has_trailing_newline);
7262                    self.range.start += "\n".len();
7263                    Chunk {
7264                        text: "\n",
7265                        ..Default::default()
7266                    }
7267                };
7268                Some(chunk)
7269            }
7270        }
7271    }
7272}
7273
7274impl MultiBufferBytes<'_> {
7275    fn consume(&mut self, len: usize) {
7276        self.range.start += len;
7277        self.chunk = &self.chunk[len..];
7278
7279        if !self.range.is_empty() && self.chunk.is_empty() {
7280            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7281                self.chunk = chunk;
7282            } else if self.has_trailing_newline {
7283                self.has_trailing_newline = false;
7284                self.chunk = b"\n";
7285            } else {
7286                self.cursor.next();
7287                if let Some(region) = self.cursor.region() {
7288                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7289                        region.buffer_range.start
7290                            ..(region.buffer_range.start + self.range.end - region.range.start)
7291                                .min(region.buffer_range.end),
7292                    );
7293                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7294                    self.excerpt_bytes = Some(excerpt_bytes);
7295                    self.has_trailing_newline =
7296                        region.has_trailing_newline && self.range.end >= region.range.end;
7297                    if self.chunk.is_empty() && self.has_trailing_newline {
7298                        self.has_trailing_newline = false;
7299                        self.chunk = b"\n";
7300                    }
7301                }
7302            }
7303        }
7304    }
7305}
7306
7307impl<'a> Iterator for MultiBufferBytes<'a> {
7308    type Item = &'a [u8];
7309
7310    fn next(&mut self) -> Option<Self::Item> {
7311        let chunk = self.chunk;
7312        if chunk.is_empty() {
7313            None
7314        } else {
7315            self.consume(chunk.len());
7316            Some(chunk)
7317        }
7318    }
7319}
7320
7321impl io::Read for MultiBufferBytes<'_> {
7322    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7323        let len = cmp::min(buf.len(), self.chunk.len());
7324        buf[..len].copy_from_slice(&self.chunk[..len]);
7325        if len > 0 {
7326            self.consume(len);
7327        }
7328        Ok(len)
7329    }
7330}
7331
7332impl io::Read for ReversedMultiBufferBytes<'_> {
7333    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7334        let len = cmp::min(buf.len(), self.chunk.len());
7335        buf[..len].copy_from_slice(&self.chunk[..len]);
7336        buf[..len].reverse();
7337        if len > 0 {
7338            self.range.end -= len;
7339            self.chunk = &self.chunk[..self.chunk.len() - len];
7340            if !self.range.is_empty() && self.chunk.is_empty() {
7341                if let Some(chunk) = self.chunks.next() {
7342                    self.chunk = chunk.as_bytes();
7343                }
7344            }
7345        }
7346        Ok(len)
7347    }
7348}
7349
7350impl<'a> Iterator for ExcerptChunks<'a> {
7351    type Item = Chunk<'a>;
7352
7353    fn next(&mut self) -> Option<Self::Item> {
7354        if let Some(chunk) = self.content_chunks.next() {
7355            return Some(chunk);
7356        }
7357
7358        if self.footer_height > 0 {
7359            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7360            self.footer_height = 0;
7361            return Some(Chunk {
7362                text,
7363                ..Default::default()
7364            });
7365        }
7366
7367        None
7368    }
7369}
7370
7371impl ToOffset for Point {
7372    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7373        snapshot.point_to_offset(*self)
7374    }
7375}
7376
7377impl ToOffset for usize {
7378    #[track_caller]
7379    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7380        assert!(*self <= snapshot.len(), "offset is out of range");
7381        *self
7382    }
7383}
7384
7385impl ToOffset for OffsetUtf16 {
7386    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7387        snapshot.offset_utf16_to_offset(*self)
7388    }
7389}
7390
7391impl ToOffset for PointUtf16 {
7392    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7393        snapshot.point_utf16_to_offset(*self)
7394    }
7395}
7396
7397impl ToOffsetUtf16 for OffsetUtf16 {
7398    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7399        *self
7400    }
7401}
7402
7403impl ToOffsetUtf16 for usize {
7404    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7405        snapshot.offset_to_offset_utf16(*self)
7406    }
7407}
7408
7409impl ToPoint for usize {
7410    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7411        snapshot.offset_to_point(*self)
7412    }
7413}
7414
7415impl ToPoint for Point {
7416    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7417        *self
7418    }
7419}
7420
7421impl ToPointUtf16 for usize {
7422    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7423        snapshot.offset_to_point_utf16(*self)
7424    }
7425}
7426
7427impl ToPointUtf16 for Point {
7428    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7429        snapshot.point_to_point_utf16(*self)
7430    }
7431}
7432
7433impl ToPointUtf16 for PointUtf16 {
7434    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7435        *self
7436    }
7437}
7438
7439impl From<ExcerptId> for EntityId {
7440    fn from(id: ExcerptId) -> Self {
7441        EntityId::from(id.0 as u64)
7442    }
7443}
7444
7445pub fn build_excerpt_ranges<T>(
7446    buffer: &BufferSnapshot,
7447    ranges: &[Range<T>],
7448    context_line_count: u32,
7449) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7450where
7451    T: text::ToPoint,
7452{
7453    let max_point = buffer.max_point();
7454    let mut range_counts = Vec::new();
7455    let mut excerpt_ranges = Vec::new();
7456    let mut range_iter = ranges
7457        .iter()
7458        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7459        .peekable();
7460    while let Some(range) = range_iter.next() {
7461        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7462        let row = (range.end.row + context_line_count).min(max_point.row);
7463        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7464
7465        let mut ranges_in_excerpt = 1;
7466
7467        while let Some(next_range) = range_iter.peek() {
7468            if next_range.start.row <= excerpt_end.row + context_line_count {
7469                let row = (next_range.end.row + context_line_count).min(max_point.row);
7470                excerpt_end = Point::new(row, buffer.line_len(row));
7471
7472                ranges_in_excerpt += 1;
7473                range_iter.next();
7474            } else {
7475                break;
7476            }
7477        }
7478
7479        excerpt_ranges.push(ExcerptRange {
7480            context: excerpt_start..excerpt_end,
7481            primary: Some(range),
7482        });
7483        range_counts.push(ranges_in_excerpt);
7484    }
7485
7486    (excerpt_ranges, range_counts)
7487}